Title of Invention	AN INTERNAL HUB TRANSMISSION FOR A BICYCLE''
Abstract	ABSTRACT 1005/MAS/98 AN INTERNAL HUB TRANSMISSION FOR A BICYCLE The present invention relates to an internal hub transmission for a bicycle comprising: a hub axle having an axle axis and a dropout attachment location for retaining the transmission to a dropout of a bicycle frame; a driver rotatably supported relative to the hub axle; an output member rotatably supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; wherein the operation mechanism comprises an elongated control rod having at least a portion that is completely surrounded by the hub axle; wherein the control rod terminates at an end face before a free end of the hub axle; an actuating mechanism mounted on the hub axle inboard of a free end of the hub axle between the dropout attachment location and the driver for moving the operation mechanism in the direction of the axle axis; and wherein the actuating mechanism extends through a radially outer surface of the hub axle at a location outside the output member and presses against the end face of the control rod in the direction of the axle axis.

Title of Invention

AN INTERNAL HUB TRANSMISSION FOR A BICYCLE''

Abstract

ABSTRACT 1005/MAS/98 AN INTERNAL HUB TRANSMISSION FOR A BICYCLE The present invention relates to an internal hub transmission for a bicycle comprising: a hub axle having an axle axis and a dropout attachment location for retaining the transmission to a dropout of a bicycle frame; a driver rotatably supported relative to the hub axle; an output member rotatably supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; wherein the operation mechanism comprises an elongated control rod having at least a portion that is completely surrounded by the hub axle; wherein the control rod terminates at an end face before a free end of the hub axle; an actuating mechanism mounted on the hub axle inboard of a free end of the hub axle between the dropout attachment location and the driver for moving the operation mechanism in the direction of the axle axis; and wherein the actuating mechanism extends through a radially outer surface of the hub axle at a location outside the output member and presses against the end face of the control rod in the direction of the axle axis.

Full Text	The present invention relates to an internal hub transmission for a bicycle, and more particularly to a bicycle internal shifter hub that can be mounted to the frame of the bicycle and that transmits the power from an input member to an output member at a specific selected gear ratio. Bicycles, particularly recreational bicycles referred to as city cruisers, are inexpensive and are easy to ride, and are thus widely used to commute to work or school or for shopping. With this type of recreational bicycle, an internal hub transmission is sometimes mounted at the rear wheel in order to ride at high speeds over flat terrain or to ride uphill with minimal exertion. An internal shifter hub generally comprises a hub axle that is fixed to the bicycle frame; a hub shell that is able to rotate around the hub axle a planet gear mechanism that is housed in the hub shell; a clutch mechanism for selecting a plurality of drive transmission paths with an interposed planet gear mechanism; and a bell crank for moving the clutch member. The clutch mechanism has a clutch member for switching the drive transmission path by moving in the axial direction, and a push rod that presses this clutch member. The bell crank is linked via a shift cable to a shift lever mounted to the handle bar, for example, in order to control shifts. With this internal shifter hub, operation of the shift lever winds and pulls the inner cable of the shift cable, causing the bell crank to push on the push rod, moving the clutch member in one axle direction, and performing a gear shift from a higher to a lower speed step. However, when the inner cable is slackened, the clutch member cannot be moved to the other side with the push rod atone. Therefore, the energizing force of a return spring or the like is utilized to move the clutch member in the other axial direction, and perform a gear shift from a lower to a higher speed step, for example. [0005] Problems Which the Invention is Intended to Solve With the conventional internal shifter hub described above, when the bicycle is pedaled and a large drive force is applied, a large amount of resistance is generated between the clutch member and the parts that make up the planet gear mechanism. Specifically, when a drive force is applied, frictional force increases in the engaged portions between the clutch member and the parts that make up the planet gear mechanism, and this makes it more difficult for the gears to be shifted by movement of the clutch.member. [ 0006 ] In order to prevent this, the clutch member must be pushed with enough force to overcome the frictional force when the inner cable is pulled and [the clutch' member is] pushed with the push rod, which means that more strength is required when the inner cable is wound. Also, the spring force of the return spring must be large enough to overcome the frictional force when the inner cable is slackened and the clutch member is returned by the return spring. If the spring force of the return spring is increased, however, then the push rod will have to be pushed at a force greater than this spring force, so greater force will be required when the inner cable is wound by the shift lever. [ 0007 ] Consequently, in order to allow the gears to be shifted in a state in which a drive force is applied during riding regardless of the direction of the shift, greater strength is needed to operate the shift lever. For this reason, in the case of an internal shifter hub, it is difficult to perform a gear shift with a light operating force in a state in which a drive force is applied during the pedaling of the bicycle. An object of the present invention is to allow a shift to be made in either direction and with a light operating force in an internal shifter hub, even when a drive force is applied during riding. [0008] Means Used to Solve the Above-Mentioned Problems The internal shifter hub pertaining to the first invention is a hub which can be mounted to the frame of the bicycle, with which the power from an input member is transmitted to an output member at the selected specific gear ratio, and which comprises a hub axle, a driver, a tubular follower, a planet gear mechanism, a first one-way clutch, second and third one-way clutches, a tubular clutch member, and a clutch control component. The hub axle can be fixed to the frame. The driver can be rotated around the hub axle and can be linked to the input member. The follower has a housing space in its interior, can be rotated around the hub axle, and can be linked to the output member. The planet gear mechanism is disposed inside the housing space of the follower, has a sun gear disposed coaxially with the hub axle, a planet gear that meshes with the sun gear, a gear frame that rotatably supports the planet gear and that can be rotated around the hub axle, and a ring gear that can be rotated around the hub axle and meshes on the outside with the planet gear, and transmits the power from the driver to the follower. The first one-way clutch is disposed between the ring gear and follower, can transmit power in only one direction, and can switch between a power transmission state and a power cut-off state in a power transmittable state. The second and third one-way clutches are respectively disposed between the driver and ring gear and between the gear frame and follower, and transmit power in only one direction. The clutch member is provided to the hub axle such that it can rotate and can move in the axial direction, switches the driver and gear frame between a linked state and a disengaged state by moving in the axial direction, and switches the first one-way clutch between a power transmission state and a power cut-off state. The clutch control component moves the clutch member in the axial direction, and engages with the clutch member so as to allow the rotational drive force of the clutch member to be converted into displacement in the axial direction. [ 0009 ] With this internal shifter hub, when the input member is rotated in one direction by disposing the clutch member in a downshift position that separates the driver and the gear frame with the clutch control component, and puts the first one-way clutch in a power cutoff state, the rotation thereof is transmitted to the ring gear via the driver and the second one-way clutch, and is outputted from the gear frame via the planet gear mechanism, reduced by (number of teeth on the ring gear) ■*■ (number of teeth on the sun gear + number of teeth on the ring gear). This reduced rotation is transmitted through the third one-way clutch from the gear frame to the follower, and the output member rotates at reduced speed in one direction. [ 0010 ] When the input member is rotated in one direction by disposing the clutch member in a direct drive position that separates the driver and the gear frame with the clutch control component, and puts the first one-way clutch in a power transmission state, the rotation is transmitted to the ring gear via the driver and the second one-way clutch, the rotation of the driver is directly transmitted to the follower via the first one-way clutch, and the output member is rotated at the same speed in one direction. £.0011 ] When the input member is rotated in one direction by disposing the clutch member in an upshift position that puts the driver and the gear frame in a direct-link state with the clutch control component, and puts the first one-way clutch in a power transmission state, the rotation thereof is transmitted to the gear frame via the driver and the clutch member, and is outputted from the ring gear via the planet gear mechanism, increased by (number of teeth on the sun gear + number of teeth on the ring gear) + (number of teeth on the ring gear). This increased rotation is transmitted through the first one-way clutch from the ring gear to the follower, and the output member rotates at increased speed in one direction. [ 0012 ]- Here, when the clutch member is moved from a downshift position to an upshift position via a direct drive position, even if rotation is transmitted to the clutch member, the clutch member will merely freewheel, and the rotational force will not be transmitted, so only a little strength is required to move the clutch member in this direction. Meanwhile, when the clutch member is moved from an upshift position to a direct drive position, friction between the clutch member and the gear frame makes it more difficult for the clutch member to separate from the gear frame, and when the clutch member is moved from a direct drive position to a downshift position, the drive force is applied to the first one-way clutch that links the gear frame to the hub shell, so it becomes more difficult to cut off the power. However, if the clutch control component is engaged with the clutch member, the rotational drive force of the clutch member is converted into displacement in the axial direction, an assist force is generated, and the clutch member makes use of the rotational drive force of the bicycle, facilitating movement in the axial direction. Accordingly, less strength is required to move the clutch member from an upshift position to a downshift position. Therefore, gear shifts can be performed in either direction with a light operating force even if a drive force is applied during riding. [ 0013 ] The bicycle internal shifter hub pertaining to the second invention is the hub defined in the first invention, wherein the clutch control component has a guide surface provided to the hub axle, a shift key for moving the clutch member in the axial direction by moving along the guide surface, and a pressing member that presses the shift key, and the clutch member is able to strike the shift key, and has a cam surface, which is inclined with respect to the axis of the hub axle, for converting rotational drive force into displacement in the axial direction by rotation in one direction when striking the shift key. [ 0014"] Here, when the shift key strikes the cam surface of the clutch member, the shift key rides up onto the cam surface as a result of the rotation of the clutch member in one direction, and the rotational drive force is converted into displacement in the axial direction of the clutch member. Accordingly, the rotational drive force can be converted into displacement in the axial direction with a simple construction. The bicycle internal shifter" hub pertaining to the third invention is the hub defined in the second invention, wherein a through-groove that goes through the axis of the hub axle and is twisted in a spiral to the opposite side from the one direction is formed in the hub axle, and the guide surface is part of the surface that forms the through-groove, and is provided such that it is inclined by a specific groove inclination angle with respect to the axis of the hub axle. [ 0015 ] In this case, since the guide surface of the through-groove is inclined with respect to the axis and is twisted in a spiral to the opposite side from the one direction, when the clutch member rotates in the one direction and the shift key rides up onto the cam surface, the shift key is pressed toward the guide surface by the cam surface along the entire length in the contact portion with the guide surface, and it is more difficult for the shift key to escape in the axial direction than for the clutch member. Furthermore, when an extremely large drive force is applied, the shift key, rather than the clutch member, will escape in the axial direction, so no shift will be performed in a state in which the drive force is extremely large, shifting shock will be reduced, and damage to the power transmission mechanism portion in the interior caused by excessive drive force will be prevented. [ 0016 ] The bicycle internal shifter hub pertaining to the fourth invention is the hub defined in the third invention, wherein the groove inclination angle is within a range of 10 to 50 degrees. If the groove inclination angle is less than 10 degrees, the shift key will tend to escape in the axial direction when pressed against the cam surface. If 50 degrees is exceeded, however, there will be a large amount of resistance when the shift key is pressed by the pressing member, and greater operating force will be needed to make a shift. [ 0017 ] The bicycle internal shifter hub pertaining to the fifth invention is the hub defined in the third or fourth invention, wherein the inclination angle of the clutch member with respect to the hub axle axis of the cam surface is greater than the groove inclination angle, and is between 20 and 70 degrees. Making the inclination angle of the cam surface greater than the groove inclination angle results in the angle of the guide surface at which the shift key actually moves being less than [that of] the cam surface when the shift key strikes the clutch member, so the shift key can move away from the cam surface. If the inclination angle is less than 20 degrees, the inclination will be too steep, and the rotational drive force cannot be converted efficiently into displacement in the axial direction, but if 70 degrees is exceeded, the slope will be too gentle, sufficient displacement in the axial direction will not be obtained, and even if the rotational drive force is converted into displacement in the axial direction, the clutch member will have difficulty separating from the gear frame, and it will be difficult to move the first one-way clutch from a power transmission state to a power cutoff state. [ 0018 ] The bicycle internal shifter hub pertaining to the sixth invention is the hub defined in the fourth or fifth invention, wherein the shift key has a triangular cross section and is disposed inside the through-groove such that the lengthwise direction thereof extends perpendicular to the hub axle. In this case, movement in the twisted through-groove is possible by means of a shift key with a simple shape, and movement in the through-groove can be restricted by frictional force. Specifically, when the cam surface strikes one of the triangular surfaces of the shift key, [the shift key] is pressed by the cam surface, the other surface comes into contact with the guide surface, and friction makes it difficult for the shift key to move in the axial direction. During the movement [of the shift key] produced by the pressing member, only one surface is in contact, and the other surface is not, so there is less resistance during movement. [ 0019 ] The bicycle internal shifter hub pertaining to the seventh invention is the hub defined in any of the second to sixth inventions, further comprising a first energizing member for energizing the clutch member to the gear frame side, a second energizing member for energizing the shift key to the clutch member side, and a third energizing member that is interposed between the shift key and clutch member, and is for energizing these two components in opposite directions by elastic force prior to the striking of the clutch member by the shift key when striking the two. [ 0020 ] Here, since the clutch member is energized to the gear frame side by the first energizing member, when the clutch member is linked to the gear frame during the movement of the clutch member to the upshift side, even if the two are not in the linked position, they can be reliably linked by rotation of the clutch member. Also, since the shift key is energized to the clutch member side by the second energizing member, the clutch member can be reliably moved to the downshift side when the clutch member moves to the downshift side. Furthermore, since the shift key and the clutch member are energized away from each other by the third energizing member, even if the shift key strikes the cam surface during a downshift, the shift key and the cam surface will separate from one another if the clutch member separates from the gear frame. Accordingly, the cam surface does not strike the shift key during riding, and no striking noise is generated. [ 0021 ] The bicycle internal shifter hub pertaining to the eighth invention is the hub defined in the seventh invention, wherein the third energizing member is a coil spring restricted to a specific overall length. In this case, the energizing force can be set for when the shift key strikes the clutch member. This means that when the separation resistance is not large, the gap between the shift key and the clutch member is the same as the set length of this energizing member, so the clutch member can be positioned more accurately. [ 0022 ] The bicycle internal shifter hub pertaining to the ninth invention is the hub defined in the seventh or eighth invention, wherein the pressing member presses the shift key to the gear frame side. In this case, in a state in which the shift key is not pressed, the clutch member is disposed in a downshift position, and as [the shift key] is pressed, it moves from a direct drive position to an upshift position. The bicycle internal shifter hub pertaining to the tenth invention is the hub defined in the ninth invention, wherein the pressing member is a rod-like member, and the energizing forces of the three energizing members are set such that the second energizing member is strongest, the third energizing member is weaker, and the first energizing member is weakest. In this case, when the pressing member is retracted to the opposite side from the pressing side, the energizing force of the second energizing member is greater than that of the other energizing members, so the clutch member can be moved by means of the second energizing member. Furthermore, since the energizing force of the third energizing member is greater than that of the first energizing member, the shift key will not readily strike the clutch member when the shift key is pressed by the pressing member so that the clutch member is moved to the upshift side by the first energizing member. [ 0023 ] The bicycle internal shifter hub pertaining to the eleventh invention is the hub defined in the ninth invention, wherein the pressing member has a rod-like controller of a specific length, an actuator mounted so as to allow relative motion in the axial direction at the distal end of the controller, and an energizing member that is interposed between the controller and actuator and that energizes the two in opposite directions, wherein the shift key is able to press the clutch member in both axial directions, and the energizing member is the first energizing member, and the energizing forces are set such that the first energizing member is strongest, the second energizing member is weaker, and the third energizing member is weakest. [ 0024 ] In this case, the shift key can be moved to the upshift side against the energizing force of the second energizing member because the energizing force of the first energizing member is greater than that of the second energizing member when the shift key is pressed by the pressing member so that the clutch member is moved from the downshift side to the upshift side. As a result, the shift key presses on the clutch member, and the clutch member moves to the upshift side. When the pressing member is retracted to the opposite side from the pressing side, the energizing force of the second energizing member is greater than that of the third energizing member, so the clutch member can be moved by means of the second energizing member. Furthermore, since the first energizing member, which has the greatest energizing force, is interposed in the pressing member, the number of coiis can be increased, and the spring constant can be reduced. As a result, the spring constant of the other energizing members can be further reduced, allowing a reduction in the operating force of the shift operation as a whole. Also, since the energizing force of the second energizing member is greater than that of the third energizing member, the shift key can be reliably made to strike the clutch member at the point when assist force is required during movement to the downshift side by the first energizing member. [ 0.025 ] The bicycle internal shifter hub pertaining to the twelfth invention is the hub defined in the seventh or eighth invention, wherein the pressing member presses the shift key to the clutch member side. In this case, in a state in which the shift key is not pressed, the clutch member is disposed in an upshift position, and moves from a direct drive position to a downshift position as it is pressed. The bicycle internal shifter hub pertaining to the thirteenth invention is the hub defined in the twelfth invention, wherein the pressing member has a rod-like controller of a specific length, an actuator mounted so as to allow relative motion in the axial direction at the distal end of the controller, and an energizing member that is interposed between the controller and actuator and that energizes the two in opposite directions, wherein the shift key is able to press the clutch member in both axial directions, and the energizing member is the second energizing member, and the energizing forces are set such that the second energizing member is strongest, the third energizing member is weaker, and the first energizing member is weakest. [ 0026 ] In this case, the shift key can move to the downshift side against the energizing force of the first energizing member because the energizing force of the second energizing member is greater than that of the first energizing member when the shift key is pressed by the pressing member so that the clutch member is moved from the upshift side to the downshift side. As a result, the shift key presses on the clutch member, and the clutch member moves to the downshift side. Also, since the energizing force of the second energizing member is greater than that of the third energizing member, the shift key can reliably strike the clutch member when an assist force is needed during movement to the downshift side. Meanwhile, when the pressing member is retracted to the opposite side from the pressing side and the clutch member is pressed by the first energizing member, the energizing force of the third energuing member is greater than that of the first energizing member, so the clutch member can be moved to the upshift side in a state in which the clutch member and the shift key are separated by the third energizing member. 10027'] Embodiments of the Invention Embodiment 1 Overall Structure: In Figure 1, the bicycle in which an embodiment of the present invention has been employed is a recreational bicycle, which comprises a frame 1 having a double-loop type of frame body 2 and a front fork 3, a handle component 4,'a drive component 5, a front wheel 6, a rear wheel 7 to which a three- speed internal shift hub 10 has been mounted, a front braking apparatus 8, and a gear shifter component 9 for operating the internal shift hub 10 close at hand. [ 0028 ] Various components including a saddle 11, the handle component 4, the front wheel 6, and the rear wheel 7 are attached to the frame 1. The handle component 4 has a handle stem 14 fixed to the upper portion of the front fork 3, and a handlebar 15 fixed to this handle stem 14. A brake lever 16, which constitutes part of the front brake apparatus 8, a grip 17, and the gear shifter component 9 are mounted at the right end of the handlebar 15. The gear shifter component 9 is mounted on the brake lever 16 on the inside of the brake lever 16, and is linked with an internal shifter hub 10 by means of a shift control cable 73 comprising an inner cable and an outer cable. The gear shifter component 9 has an ordinary structure having a winding lever for winding the inner cable, and a release lever that releases the winding operation of the winding lever and plays out the inner cable, and as such will not be described in detail herein. [ 0029 ] The drive component 5 has a gear crank 18 that is provided to the lower portion (bottom bracket portion) of the frame body 2, a chain 19 that goes around the gear crank 18, and the internal shifter hub 10. Structure of the Internal Shifter Hub The internal shifter hub 10 is a coaster brake-equipped hub with a three-stage structure including power transmission paths for downshifting, direct drive, and upshifting. As shown in Figure 2, this internal shifter hub 10 has a hub axle 2] fixed to the rear pawl 2a of the frame body 2 of the bicycle, a driver 22 disposed around the outer periphery at one end of the hub axle 21, a hub shell 23 disposed further around the outer periphery of the hub axle 21 and the driver 22, a planet gear mechanism 24, an operation mechanism 25 for selecting a power transmission path, a bell crank 26 for actuating the operation mechanism 25, and a coaster brake 27. [ 0030 ] As shown in Figures 2 and 3, the hub axle 21 is a rod-like member which has a larger diameter in its middle and a smaller diameter at both ends, and on which threads are formed at both ends. An operation hole 21a is formed in the axial portion of the hub axle 21 from the right end to the center in Figure 2. A through-groove 21b that goes through the axis is formed in the vicinity of the bottom of the operation hole 21a. The through-groove 21b goes through the axis of the hub axle 21 and is inclined by a specific groove inclination angle p (see Figure 5) with respect to the axis, and is formed in a twist to the side opposite the forward direction going from the right to the left in Figure 5. This through-groove 21b is formed by using an end drill of a specific diameter to form holes that go through the axis, and then feeding [the drill] toward the center in the axial direction while the hub axle 21 is slowly rotated in the forward direction. Therefore, this through-groove 21b is shaped as a continuous spiral in which the through-holes intersecting at both ends rotate gradually according to movement in the axial direction. This groove inclination angle \|3 should range from 10 to 50 degrees. [ 0031 ] One end of the driver 22 is rotatably supported on the hub axle 21 via balls 30 and a hub cone 31, and a hub cog 32 is fixed around the outer periphery at one end. A plurality of serration inner teeth 22a are formed in the axial direction around the inner periphery at the other end of the driver 22. The hub shell 23 is a tubular member, and a housing space 23a around the inner periphery thereof houses the driver 22 and the planet gear mechanism 24. The hub shell 23 is able to rotate around the hub axle 21 via balls 33 and 34 and a hub cone 35. Hubs 36 and 37 for supporting spokes 7a (see Figure 1) are fixed at both ends of the outer periphery of the hub shell 23. [0032] Structure of the Planet Gear Mechanism The planet gear mechanism 24 has a sun gear 40 formed coaxially and integrally with the hub axle 21, a gear frame 4.1 disposed around the outer periphery of the hub axle 21, three planet gears 42 (only one planet gear is shown in the figure) that mesh with the sun gear 40, and a ring gear 43. [ 0033 ] The gear frame 41 is a tubular member, and is rotatably supported on the hub axle 21. Three notches 41a are formed in the circumferential direction in the gear frame 41, and the planet gears 42 are rotatably supported by pins 44 in these various notches 41a. Serration inner teeth 41b are formed around the inner periphery at one end of the gear frame 41, and serration outer teeth 41c (Figure 1) are formed around the outer periphery at the other end. [ 0034 ] The ring gear 43 is formed in a nearly cylindrical shape, and extends from the planet gears 42 to the outer periphery of the driver 22. Inner teeth 43b are formed around the inner periphery at the other end of the ring gear 43. The planet gears 42 mesh with the sun gear 40 as mentioned above, but at the same time also mesh with the inner teeth 43b of the ring gear 43. A notch 43a is formed at one end of the ring gear 43, and a clutch pawl 53 that makes up part of a first one-way clutch 50 as shown in Figure 4 is swingably supported by a pin 54 in'this notch 43a. This clutch pawl 53 is energized in the standing direction by a torsion coil spring 55. The first one-way clutch 50 transmits only rotational drive force in the forward direction from the ring gear 24 [sic] to the hub shell 23. The clutch pawl 53 meshes with the ratchet teeth 23b formed on the inner peripheral surface of the hub shell 23 only when the ring gear 24 [sic] has rotated in the forward direction. Even when in a transmission-enabled state in which the ring gear 24 [sic] rotates in the forward direction, this first one-way clutch 50 is able to switch between a power transmission state in which the clutch pawl 53 meshes with the ratchet teeth 23b, and a transmission cutoff state of retraction from the ratchet teeth 23b, which is accomplished by the movement of the clutch member as discussed below. [ 0035 ] A second one-way clutch 51 that transmits rotational drive force only in the forward direction from the driver 22 to the ring gear 24 [sic] is arranged between the driver 22 and the ring gear 24 [sic], A third one-way clutch 52 that transmits rotational drive force only in the forward direction from the gear frame 41 to the hub shell 23 is arranged between the gear frame 41 and the hub shell 23. The third one-way clutch 52 has a tubular clutch case 56 in which serration inner teeth 56a are formed around the inner periphery at one end. These serration inner teeth 56a engage with the serration outer teeth 41c of the gear frame 41, and the clutch case 56 rotates integrally with the gear frame 41. These two one-way clutches 51 and 52 are unable to perform switching in a transmission-enabled state, unlike the First one-way clutch 50. [0036] Structure of the Operation Mechanism The operation mechanism 25 is used to select the power transmission path, and has a clutch member 45 and a clutch control component 46. The clutch member 45 switches the driver 22 and gear frame 41 between a linked state and a separated state, and also switches the first one-way clutch 50 between a power transmittable state and a power cutoff state. The clutch member 45 is positioned around the outer periphery of the hub axle 21 such that it can move and rotate in the axial direction. [ 003? J The clutch member 45 is a tubular member as shown in Figure 4, and has serration outer teeth 45a formed around the outer periphery at one end thereof. The serration outer teeth 45a are slidably engaged with the serration inner teeth 22a. A large diameter component 45b is formed at the other end of the clutch member 45, and serration outer teeth 45c are formed around the outer periphery thereof. The serration outer teeth 45c are able to engage with the serration inner teeth 41b formed on the gear frame 41. A Taper surface 45d is formed between the large diameter component 45b and one end. This taper surface 45d is provided in order to lower the clutch pawl 53 of the first one-way clutch 50 from its erected position (power transmission position) indicated by the solid line to its retracted position (power cutoff position) indicated by the two-dot chain line. When the clutch member 45 moves from the left to the downshift position on the right end, the clutch pawl 53 follows along the taper surface 45d, rides up onto the large diameter component 45b, and is lowered into a retracted attitude. [ 0038 ] As shown in Figure 3, two step components 45e and 45f are formed around the inner periphery of the clutch member 45 with spaces between them in the axial direction. As shown in Figure 4, a plurality of cam surfaces 47 are formed on the left step component 45f with spaces between them in the circumferential direction. As shown in Figure 5, the cam surfaces 47 have a flat surface 47a that is depressed at one end, a curved surface 47b that leads downstream in the forward direction A of the flat surface 47a, and an inclined surface 47c that leads upstream. The inclination angle a with respect to the axis of this inclined surface 47c should be greater than the groove inclination angle P of the through-groove 21b, and between 20 and 70 degrees. 'E-0039 ] The clutch control component 46 moves the clutch member 45 in the axial direction of the hub axle 21, and engages with the clutch member 45 to convert the rotational drive force of the clutch member 45 into displacement in the axial direction. The clutch control component 46 has a push rod 48 that moves in the axial direction through the operation hole 21a, and a shift key 49 that is pressed to the gear frame 41 side by the push rod 48, as shown in Figure 3. •4J-9040 }■ ■ As shown in Figure 6, the push rod 48 has an operator 65 of a specific length, an actuator 66 that is mounted on the distal end of the operator 65 such that the former can move in the axial direction, and a first coil spring 60 that is positioned between the operator 65 and the actuator 66. The operator 65 has a rod component 68 and a strike component 69 threaded onto the rod component 68. A threaded component 68a is formed on the base end of the rod component 68, and a large diameter component 68b is formed on the distal end. This threaded component 68a is threaded into the strike component 69. The large diameter component 68b is slidably mounted in a guide hole 66a formed in the interior of the actuator 66. The guide hole 66a has a smaller diameter on the actuator 66 side, which keeps the actuator 66 from coming out. The first coil spring 60 is inserted in a compressed state between the end surface of the actuator 66 and the end component of the strike component 69, and energizes the actuator 66 and the operator 65 away from each other, so that when the actuator 66 presses on the shift key 49, the clutch member 45 is energized to the gear frame 41 side. -t-QtWH,,, As shown in Figure 4, the shift key 49 is a rod-like member with a triangular cross section, and when pressed, moves through the through-groove 21b while turning in the opposite direction from the forward direction, that is, while twisting. The contact surface 49b of the shift key 49 onto the through-groove 21b is formed at an angle that follows the through-groove 21b. For example, when the groove inclination angle p of the through-groove 21b is 30 degrees, the angle of the contact surface 49b with respect to the axis is also about 30 degrees. The outward movement of the shift key 49 is restricted to within the clutch member 45 by a stop ring 63 mounted around the inner periphery at the other end of the clutch member 45. Therefore, [the shift key 49] cannot actually come out of the clutch member 45 as shown in Figure 4. As a result, the shift key 49 is pressed by the push rod 48 and moves the clutch member 45 to the left in Figure 3. [ 0042 }• The shift key 49 is able to strike the cam surfaces 47 inside the clutch member 45. If the clutch member 45 is rotated in the forward direction in a state in which the shift key 49 has struck the fiat component 47a of the cam surface 47, then the shift key 49 is pressed to the guide surface 21c side of the through-groove 21b by the inclined surface 47c of the cam surface 47, and its motion to the left in the axial direction is restricted, so the clutch.member 45 moves to the right in the axial direction. Specifically, the rotational drive force of the clutch member 45 is converted into displacement in the axial direction to assist shift control. £-9043 ]" A notch 49a is formed at both ends of the shift key 49, and in this notch 49a is stopped a second coil spring 61 that is stopped at one end on the hub axle 21. The shift key 49 is constantly energized to the clutch member 45 side by this second coil spring 61. A third coil spring 62 is interposed between the shift key 49 and the clutch member 45. The third coil spring 62 is restricted to a specific overall length by a restricting member (not shown), and when compressed, energizes the shift key 49 and the clutch member 45 away from each other before the former strikes the latter. As a result, the clutch member 45 remains at a constant distance from the shift key 49 during movement, and is accurately positioned. f-6©44^~ Here, the energizing forces of the first through third coil springs 60, 61, and 62 decrease in that order. Specifically, the spring forces decrease in that order. Here, if the spring force of the first coil spring 60 is less than that of the second coil spring 61, then even if the shift key 49 is pressed by the push rod 48, the first coil spring 60 will bend and the shift key 49 will not move. If the spring force of the second coil spring 61 is less than that of the third coil spring 62, then even if the shift key 49 is pressed by the second coil spring 61, the shift key 49 will not go into the cam surface 47, and shift control cannot be assisted. f-0Q45 ] The first coil spring 60 is positioned in a relatively large space between the operator 65 and the actuator 66 inside the operation hole 21a, so it is possible to increase the number of coils and thereby lower the spring constant and the spring force. Accordingly, the spring constants and spring forces of the second and third coil springs 61 and 62 can be further lowered, allowing a reduction in the force required to press the push rod 48 during an upshift, that is, the operating force of the winding lever in the shift control component 9. As a result, there is less tension on the inner cable, and the inner cable does not break as frequently. Structure of the Bell Crank The bell crank 26 is mounted at the axial end of the hub axle 21. The bell crank 26 comprises a support bracket 70 mounted at the axial end, and a link member 71 swingably supported by the support bracket 70. The outer casing 73a of a shift control cable 73 is stopped at this support bracket 70, and an inner cable 73b is stopped at the link member 71. The distal end of the link member 71 strikes the base end of the push rod 48. Here, pulling the inner cable 73b by means of the shift control component 9 swings the link member 71, presses the push rod 48, and executes an upshift. When the inner cable is slackened, the clutch member 45 is pressed by the second coil spring 61 via the shift key 49, and a downshift is executed. -£0047] Structure of the Coaster Brake As shown in Figure 1, the coaster brake 27 is mounted to the brake case 56. The coaster brake 27 comprises a brake roller 57 supported by the brake case 56, a cam surface 41d formed around the outer periphery at the other end of the gear frame 41, and a brake shoe 58 that exerts a braking action on the inner surface at the other end of the hub shell 23. The brake roller 57 is designed such that it is pushed outward in the radial direction by the cam surface 41d when the driver 22 rotates in the reverse direction. As a result, the brake shoe 58 comes into contact with and brakes the inner surface of the hub shell 23. ' [ 0048 ] " Brake lock tends to occur when the coaster brake 27 is installed. Brake lock is a phenomenon whereby, if the first one-way clutch 50 is in a power transmission state when the rider pedals backward to brake, the drive force will be transmitted in a state in which the brake is applied, and the brake cannot be released. A pawl cage 59 is mounted to the first one-way clutch 50 in this embodiment in order to prevent this phenomenon. ^0049^- The pawl cage 59 provides a specific angle of play between the ratchet teeth 23b of the hub shell 23 and the clutch pawl 53 of the first one-way clutch 50, and allows the brake to be released while the ring gear 43 rotates by this amount of play. Specifically, the pawl cage 59 either prevents the clutch pawl 53 from being erected at a specific angle, or, even if it is erected, allows it to be erected at a position where it ' Translator's note: "56" is referred to as a "clutch case" above; possible error. cannot stop the ratchet teeth 23b at the specific angle, and delays the time when the clutch pawl 53 is stopped by the ratchet teeth 23b during initial drive. [•0050-3- Shift Actuation Because of this planet gear mechanism 24 and one-way clutches 50 to 52, this internal shifter hub 10 has: a downshift power transmission path made up of the driver 22, the ring gear 43, the planet gear mechanism 24, the gear frame 41, and the hub shell 23; a direct drive power transmission path made up of the driver 22, the ring gear 43, and the hub shell 23, and an upshift power transmission path made up of the driver 22, the clutch member 45, the gear frame 41,' the planet gear mechanism 24,2 the ring gear 43, and the hub shell 23. [ 0051-j- Shifting is performed by operating the push rod 48 with the bell crank 26 via the shift control cable 73. Down shift-Upshift Actuation In the state shown in Figure 3, in which the push rod 48 is not pushed in, the clutch member 45 is disposed in the downshift position at the right end, and the rotation from the driver 22 is transmitted to the hub shell 23 after being reduced in speed via the downshift power transmission path. Specifically, the rotation inputted to the driver 22 is transmitted to the ring gear 43 via the second one-way clutch 51. At this point, the clutch pawl 53 of the first one-way clutch 50 is rotated by the clutch member 45 to the retracted attitude shown by the two-dot chain line in Figure 4, and the first one-way clutch 50 is in a power cutoff state. Accordingly, the rotation transmitted to the ring gear 43 is further transmitted to the hub shell 23 via the planet gear mechanism 24, the gear frame 41, and the third one-way clutch 52. In this case, the inputted rotation is reduced in speed according to the gear shift ratio determined by the numbers of teeth of the sun gear 40, the planet gears 42, and the ring gear 43. [-00-5 2-j Meanwhile, if the winding lever of the shift control component 9 is operated, the link member 71 of the bell crank 26 swings and pushes in the push rod 48 by one stage. As a result, since the spring force of the first coil spring 60 is greater Translator's note: "71" in the original; probable typo. " Translator's note: "54" in the original; probable typo. than the spring force of the second coil spring 61, the shift key 49 is pushed by the link member 71 via the push rod 48, guided into the through-groove 21b, and moved to the left in Figure 3 while rotating around the hub axle, and the clutch member 45 is also pushed via the stop ring 63, and moves to-the direct drive position. Once the clutch member 45 is disposed in the direct drive position shown in Figure 7, the clutch pawl 53 of the first one-way clutch 50, which had been put into a retracted attitude by the taper surface 45d, is returned to the erected attitude shown by the solid line in Figure 4 by the spring force of the torsion coil spring 55. In this state, the first one¬way clutch 50 is able to transmit only rotation in the forward direction from the ring gear 43 to the hub shell 23. Therefore, the rotation from the driver 22 is directly transmitted to the hub shell 23 through the direct drive power transmission path. Specifically, the rotation inputted to the driver 22 is transmitted to the ring gear 43 via the second one-way clutch 51, then is transmitted to the hub shell 23 via the first one¬way clutch 50, and the rotation of the driver 22 is transmitted directly to the hub shell 23 via the ring gear 43. At this point, the rotation is transmitted from the ring gear 43 to the gear frame 41 via the planet gear mechanism 24, and the gear frame 41 rotates at reduced speed, but since the rotation of the hub shell 23 is faster than that of the gear frame 41, there is no transmission of the rotation from the gear frame 41 to the hub shell 23 via the third one-way clutch 52. [-0053 ] When the winding lever is operated from the direct drive state and the push rod 48 is pushed in further, the shift key 49 moves further to the left, and the clutch member 45 also moves correspondingly to the upshift position. When the clutch member 45 is disposed in the upshift position shown in Figure 8, the serration outer teeth 45c of the clutch member 45 and the serration inner teeth 41b of the gear frame 41 mesh with each other. In this movement to the upshift position, when the serration outer teeth 45c and the serration inner teeth 41b are disposed in the positions where they mesh, the clutch member 45 moves directly to the upshift position to the left after the clutch member 45 strikes the gear frame 41, When, however, [these teeth] are disposed in positions where they do not mesh, the shift key 49 and the clutch member 45 temporarily halt their movement to the left at the point when the clutch member 45 strikes the gear frame 41. When this happens, the actuator 66 of the push rod 48 retracts, the first coil spring 60 is compressed, and the shift key 49 is pressed. When the clutch member 45 then rotates and the two sets of teeth 45c and 41b reach their meshing positions, the spring force of the first coil spring 60 moves the clutch member 45 via the shift key 49, and the two sets of teeth 45c and 41b mesh. fQQS4-}. in this state, the rotation transmitted to the driver 22 is transmitted to the hub shell 23 via the upshift transmission path. Specifically, it is transmitted from the driver 22, through the clutch member 45, and to the gear frame 41, and the rotation transmitted to the gear frame 41 is transmitted to the hub sheli 23 via the planet gear mechanism 24, the ring gear 43, and the first one-way clutch 50. In this case, the inputted rotation is increased in speed and outputted according to the gear shift ratio determined by the numbers of teeth of the sun gear 40, the planet gears 42, and the ring gear 43. There is an attempt at this point to transmit the rotation from the driver 22 toward the ring gear 43 via the second one-way clutch 51, but since the rotation of the ring gear 43 is faster than that of the driver 22, no rotation is transmitted from the second one-way clutch 51. [■0055'] Since rotation is transmitted directly between the driver 22 and the ring gear 43 during such a shift from the downshift side to the upshift side, it is best to move the clutch member 45, which has no force acting upon it. Accordingly, the spring force of the first coil spring 60 for pushing the clutch member 45 may be reduced, and furthermore, since the spring force of the second coil spring 61 is lower than this, shift operation can be performed with a light force. Upshift-Downshift Assist Actuation When the release lever of the shift control component 9 is operated at the upshift position shown in Figure 8, the energizing force of the first coil spring 60 is removed, and the second coil spring 61 presses on the shift key 49 and causes the push rod 48 to retract by one stage to the right. The shift key 49 then presses on the clutch member 45 via the third coil spring 62, and attempts to move the clutch member 45 to the direct drive position. When the rider is not pedaling and no drive force is being transmitted, the clutch member 45 separates from the gear frame 41, and the clutch member 45 moves to the direct drive position. If the rider is pedaling, however, since drive force is being transmitted from the clutch member 45 to the gear frame 41, frictional force may cause the serration inner teeth 41b and the serration outer teeth 45b to remain meshed. In a case such as this, the spring force of the second coil spring 61 alone will not move the clutch member 45 to the right in Figure 8. In a state such as this, when the shift key 49 strikes the flat surface 47a of the cam surface 47 of the clutch member 45 as shown in Figure 5, the shift key 49 is pressed to the guide surface 21c side over the entire length of the portion inserted in the through-groove 21b, and is prevented by frictional force from escaping in the axial direction. As a result, when the shift key 49 rides up on the inclined surface 47c, the clutch member 45 moves to the right. When the serration inner teeth 41b and the serration outer teeth 45c are then unmeshed, the clutch member 45 is pressed by the second coil spring 61 via the shift key 49 and moves to the direct drive position. Specifically, contact between the cam surface 47 of the clutch member 45 and the shift key 49 assists shifting by converting the rotational motion of the clutch member 45 into displacement in the axial direction. [-0057 f Here, the shift key 49 cannot readily escape to the left in the axial direction as mentioned above because it is pressed by the second coil spring 61, and the through-groove 21b is inclined and twisted in a spiral with respect to the axis. Therefore, the shift key 49 will not escape in the axial direction when the transmitted drive force is less than the energizing force of the second coil spring 61 and the frictional force between the shift key 49 and the guide surface 21c. However, when a drive force greater than these is applied, the shift key 49 may overcome the energizing force of the second coil spring 61 and the frictional force with the guide surface 21c and escape to the left in the axial direction without the clutch member 45 moving. The above-mentioned frictional force here can be set by means of the groove inclination angle fi. If this groove inclination angle (3 is set to high, then it will be difficult for the shift key 49 to move to the teft when the shift key 49 is pushed by the push rod 48. If the groove inclination angle (3 is set too low, however, the resistance will be smaller during pushing by the push rod 48, but the frictional force will also decrease. Therefore, this groove inclination angle p should be between 10 and 50 degrees. It is possible to adjust the drive force at the limit where the shift key 49 escapes during assist by adjusting this groove inclination angle p, the inclination angle a of the inclined surface 47c of the cam surface 47, and the spring force of the three coil springs 60 to 62. f 0058 i MeanwhiJe, even when a drive force Jarger than the set drive force is applied, and the shift key 49 escapes in the axial direction without the clutch member 45 moving, once the gear crank 18 reaches the vicinity of top dead center or bottom dead center and the drive force decreases, the clutch member 45 will be pressed by the assist force produced by the shift key 49, and will move to the right. Accordingly, a shift will not be performed when an extremely large drive force is applied, such as on a steep hill, which reduces shifting shock and helps prevent damage to the drive force transmission parts, such as the serration teeth and the one-way clutches. [■©9§9i When the clutch member 45 moves, the shift key 49 is separated from the cam surface 47 by the third coil spring 62. Accordingly, there will be no noise generated by contact with the shift key 49 even if the clutch member 45 is rotated. In the direct drive position shown in Figure 7, rotation is transmitted from the driver 22 to the hub she!! 23 via the direct drive transmission path, as discussed above. [-0060 } When the release lever is operated in a state in which the clutch member 45 is disposed in the direct drive position, the push rod 48 retracts further, and the shift key 49 presses on the clutch member 45. At this point the taper surface 45d of the clutch member 45 comes info contact with the clutch pawl 53 of the first one-way clutch 50 and attempts to lower the clutch pawl 53 from an erected attitude to a retracted attitude. However, because the clutch pawl 53 is transmitting power from the ring gear 43 to the hub shell 23, it is not readily lowered to a retracted attitude by the energizing force of the second coil spring 61 alone. Here again, when the shift key 49 strikes the cam surface 47 of the clutch member 45, an assist force is generated just as discussed above, the clutch member 45 is moved in the axial direction, and the clutch pawl 53 can be lowered. ["0061]" Here, since rotation is transmitted directly to the ring gear 43, without going through the clutch member 45, there is a reduction in the operating force required during shifting in an upshift operation from the downshift side to the upshift side. Furt! crmore, since the rotational force of the clutch member 45 is assisted by being converted into displacement in the axial direction in a downshift operation from the upshift side to the downshift side, the rider can make a shift with a light force while still pedaling, even when upshifting. [■ 0062] Embodiment 2 In the above Embodiment 1, a reduction in spring force was achieved during an upshift by installing the first coil spring 60 around the push rod, but the push rod 48a may instead be a rod-like member/ as shown in Figure 9. In this case, the first coil spring 60 is disposed in a compressed state between the clutch member 45 and the hub cone 31. The spring forces of the three coil springs 60 to 62 becomes increasingly smaller in the order of the second coil spring 61, the third coil spring 62, and the first 1 Translator's note: The first "rod" is phonetically rendered from the English in the original, whereas the second is written with the Chinese character for rod. The intended meaning here seems to be that the rod is by itself, with no spring attached. coil spring 60. Here, if the energizing force of the second coil spring 61 is less than that of the third coil spring 62, then even if the shift key 49 is pressed in the retraction of the push rod 48a to the downshift side, the shift key 49 will not strike the clutch member 45, and no assist force will be obtained. Also, if the energizing force of the third coil spring 62 is less than that of the first coil spring 60, then when the push rod 48a1 is retracted to the downshift side and the second coil spring 61 presses on the shift key 49, the third coil spring 62 will bend, only the shift key 49 will move, and the shift key 49 and the clutch member ,45 will not be able to move away from each other, so the clutch member 45 cannot be positioned. The shift key 49 moves the clutch member 45 only on the downshift side, and the two move independently on the upshift side. In other words, a stop ring is not provided to the clutch member 45. The overall length of the third coil spring 62 is restricted to a specific length by a restricting member (not shown), and the spacing between the clutch member 45 and the shift key 49 is always kept the same even when the two move independently. The rest of the structure is the same as in Embodiment 1, and will not be described here. [0063}- Down shift-Upshift Actuation In this Embodiment 2, in the state shown in Figure 9, in which the push rod 48a is not pushed in, the 45 is disposed at the downshift position on the right end, and the rotation from the driver 22 is transmitted to the hub shell 23 after being reduced in speed via the downshift power transmission path, just as in Embodiment 1. Specifically, the rotation inputted to the driver 22 is transmitted to the ring gear 43 via the second one-way clutch 51. j; 0064] Meanwhile, when the winding lever of the shift control component 9 is operated, the link member 71 of the bell crank 26 swings, and the push rod 48a is pushed in by one stage. As a result, the shift key 49 is pressed by the push rod 48a and moves to the left while rotating around the hub axle, and the clutch member 45, which is energized by the first coil spring 60, follows the shift key 49 and moves to the direct drive position. When the clutch member 45 is then disposed in the direct drive position, the clutch pawl 53 of the first one-way clutch 50, which had been put in a retracted attitude by the taper surface 45d, is returned to the erected attitude shown by the solid line in Figure 4 by the spring force of the torsion coil spring 55, and the 1 Translator's note: "48" in the original; probable typo. rotation from the driver 22 is directly transmitted to the hub shell 23 through the direct drive power transmission path, just as in Embodiment I. [0065} When winding lever is operated in the direct drive position and the push rod 48a is pushed in further, the shift key 49 moves further to the left, and the clutch member 45 follows this and also moves to the upshift position. When the clutch member 45 is disposed in the upshift position, the serration outer teeth 45c of the clutch member 45 and the serration inner teeth 41b of the gear frame 41 mesh with each other. In this movement to the upshift position, when the serration outer teeth 45c and the serration inner teeth 41b are disposed in the positions where they mesh, the clutch member 45 moves directly to the upshift position to the left after the clutch member 45 strikes the gear frame 41. When, however, [these teeth] are disposed in positions where they do not mesh, the clutch member 45 temporarily halts its movement to the left at the point when the clutch member 45 strikes the gear frame 41. However, since the clutch member 45 is pressed by the energizing force of the first coil spring 60, when the clutch member 45 rotates and the two sets of teeth 45c and 41b reach their meshing positions, the clutch member 45 moves and the two sets of teeth 45c and 41b mesh. In this state, the rotation transmitted to the driver 22 is transmitted to the hub shell 23 via the upshift transmission path just as in Embodiment 1. E-QQ66] Since rotation is transmitted directly between the driver 22 and the ring gear 43 during such a shift from the downshift side to the upshift side, it is best to move the clutch member 45, which has no force acting upon it. Accordingly, the spring force of the first coil spring 60 for pushing the clutch member 45 may be reduced, and shift operation can be performed with a light force. Upshift-Downshift Assist Actuation When the release lever of the shift control component 9 is operated at the upshift position, the shift key 49 is energized by the second coil spring 61, and the push rod 48a retracts by one stage to the left. The shift key 49 then presses on the clutch member 45 and attempts to move the clutch member 45 to the direct drive position. If the rider is pedaling, however, since drive force is being transmitted from the clutch member 45 to the gear frame 41, frictional force may cause the serration inner teeth 41b and the serration outer teeth 45b to remain meshed. In a case such as this, an assist force is generated and the clutch member 45 moved to the downshift side, just as in Embodiment 1 above. [•096?} Meanwhile, even when a drive force larger than the set drive force is applied, and the shift key 49 escapes in the axial direction without the clutch member 45 moving, once the gear crank 18 reaches the vicinity of top dead center or bottom dead center and the drive force decreases, the clutch member 45 will be pressed and moved by the assist force produced by the shift key 49. Accordingly, again in this Embodiment 2, a shift will not be performed when an extremely large drive force is applied, which reduces shifting shock and helps prevent damage to the drive force transmission parts, such as the serration teeth and the one-way clutches. J-QG6&}- When the clutch member 45 moves to the right, the shift key 49 is separated from the cam surface 47 by the third coil spring 62. Accordingly, there will be no noise generated by contact with the shift key 49 even if the clutch member 45 is rotated. When the clutch member 45 is then disposed in the direct drive position, rotation is transmitted via the direct drive transmission path. When the release lever is operated in a state in which the clutch member 45 is disposed in the direct drive position, the push rod 48a retracts further, and the shift key 49 presses on the clutch member 45. At this point the taper surface 45d of the clutch member 45 comes into contact with the clutch pawl 53 of the first one-way clutch 50 and attempts to lower the clutch pawl 53 from an erected attitude to a retracted attitude. However, because the clutch pawl 53 is transmitting power from the ring gear 43 to the hub shell 23, it is not readily lowered to a retracted attitude by the energizing force of the second coil spring 61 alone. Here again, when the shift key 49 strikes the cam surface 47 of the clutch member 45, an assist force can be generated and the clutch member 45 moved in the axial direction, just as discussed above. [-3669? The same merits as in Embodiment 1 are obtained here as well, and in addition, the structure of the push rod 48 is simplified. In this case, however, since the energizing force is largest for the second coil spring 61, which is located in a relatively narrow space, if sufficient bending is ensured, then it is difficult to reduce the spring constant of the second coil spring 61, and there is a sharp increase in the spring force during bending. Consequently, a greater operating force is required during upshifting than in Embodiment 1. r nmm Embodiment 3 In Embodiment 2 above, the clutch member was disposed in the downshift position in a state in which it was not pressed by the push rod, but in this Embodiment 3, the clutch member 45 is disposed in the upshift position, as shown in Figure 10. In this case, the second coil spring 61 is installed on the push rod 48. Also, the first coil spring 60 is disposed between the clutch member 45 and the hub cone 31. Also, the energizing forces of the three coil springs 60 to 62 becomes increasingly smaller in the order of the second coil spring 61, the third coil spring 62, and the first coil spring 60. The reason for setting the energizing forces of the springs in this way is the same as in Embodiment 2. [%005l^ As shown in figure 10, the operation hole 21a is formed along the axis from the left end (in Figure 10) of -the hub axle (the side on which the coaster brake is mounted) to the center. A bell crank (not shown) is mounted at the axial end on the left side of the hub axle 21. Because the push rod 48 strikes the triangular top of the shift key 49a, a notch surface 49b that strikes the push rod 48 is formed in the center of the shift key 49a. The first coil spring 60 is disposed in a compressed state between the clutch member 45 and the hub cone 31, just as in Embodiment 2, The rest of the structure is the same as in Embodiment 2, and will not be described here. [ 0072] Upshift-Downshift Assist Actuation In this Embodiment 3, in the state shown in Figure 10, in which the push rod 48 is not pushed in, when the winding lever of the shift control component 9 is operated in the upshift position, the shift key 49a is pressed by the push rod 48, and the clutch member 45 is moved to the downshift side against the energizing force of the first coil spring 60. At this point, when no drive force is being transmitted, the shift key 49a presses the clutch member 45 via the third coil spring 62, and the clutch member 45 is moved to the direct drive position. When a drive force is being transmitted, the shift key 49a strikes the cam surface 47 while bending the third coil spring 62 or the second coil spring 61, and moves the clutch member 45 by means of the above-mentioned assist force. When the movement is from the direct drive position to the downshift position, if a drive force has been transmitted and it is difficult for the clutch pawl 53 to assume a retracted attitude, then the clutch member 45 is moved by the assist force, the clutch pawl 53 is put into a retracted attitude, and the clutch member 45 is moved to the downshift position. E-QQ73-] Meanwhile, even when a drive force larger than the set drive force is applied, and the shift key 49a escapes in the axial direction without the clutch member 45 moving, once the gear crank 18 reaches the vicinity of top dead center or bottom dead center and the drive force decreases, the clutch member 45 will be pressed and moved by the assist force produced by the shift key 49a. Accordingly, again in this Embodiment 3, a shift will not be performed when an extremely large drive force is applied, which reduces shifting shock and helps prevent damage to the drive force transmission parts, such as the serration teeth and the one-way clutches. Downshift-Upshift Actuation When the release lever is operated in the downshift position, the clutch member 45 is pressed to the upshift side by the energizing force of the first coil spring 60, the push rod 48 moves, and the clutch member 45 moves to the direct drive position. When the clutch member 45 is then disposed in the direct drive position, the clutch pawl 53 of the first one-way clutch 50, which had been put in a retracted attitude by the taper surface 45d, is returned to the erected attitude shown by the solid line in Figure 4 by the spring force of the torsion coil spring 55, and the rotation from the driver 22 is directly transmitted to the hub shell 23 through the direct drive power transmission path, just as in Embodiments 1 and 2. ■{-0075}- When the release lever is operated in the direct drive position and the clutch member 45 is pressed to the upshift side by the energizing force of the first coil spring 60, the push rod 48 moves and the clutch member 45 moves to the upshift position. When the clutch member 45 is disposed in the upshift position, the serration outer teeth 45c of the clutch member 45 and the serration inner teeth 41b of the gear frame 41 mesh with each other. In this movement to the upshift position, when the serration outer teeth 45c and the serration inner teeth 41b are disposed in the positions where they mesh, the clutch member 45 moves directly to the upshift position to the left after the clutch member 45 strikes the gear frame 41. When, however, [these teeth] are disposed in positions where they do not mesh, the clutch member 45 temporarily halts its movement to the left at the point when the clutch member 45 strikes the gear frame 41. However, since the clutch member 45 is pressed by the energizing force of the first coil spring 60, when the clutch member 45 rotates and the two sets of teeth 45c and 41b reach their meshing positions, the clutch member 45 moves and the two sets of teeth 45c and 41b mesh. In this state, the rotation transmitted to the driver 22 is transmitted to the hub shell 23 via the upshift transmission path just as in Embodiments 1 and 2. [-69?6j Since rotation is transmitted directly between the driver 22 and the ring gear 43 during such a shift from the downshift side to the upshift side, it is best to move the clutch member 45, which has no force acting upon it. Accordingly, the spring force of the first coil spring 60 for pushing the clutch member 45 may be reduced. Furthermore, since the energizing force is largest for the second coil spring 61, which has plenty of housing space, the spring force can be reduced overall, and a shift can be performed with a light force in a state in which a drive force is applied during riding. Other Practical Examples (a) The push rod in Embodiment 3 may consist of a rod-like member as in Embodiment 2. In this case, since the shift key is restricted in its movement to the axial end side by the push rod, a through-groove may be formed along the axis. In an embodiment such as this, a shift can be made at any time since an assist force will be generated even if a large force is applied. However, the push rod will be subjected to a large force here, as will the inner cable. The shifting shock will also be considerable, so the power transmission parts will have to be made stronger. (b) In these embodiments, a pawl cage for preventing brake lock was provided since a coaster brake was installed, but no pawl cage is necessary if a coaster brake is not installed. (c) The mechanism for transmitting rotation is not limited to a planet gear mechanism, and may instead be a planet roller mechanism. Merits of the Invention As discussed above, with the internal shifter hub pertaining to the present invention, the engagement of the clutch member with the clutch control component in the movement of the clutch member to the downshift side converts the rotational drive force of the clutch member into displacement in the axial direction and generates an assist force, so movement of the clutch member is facilitated and the clutch member can be moved with a light force even during riding. The clutch member can also be moved with a light force because no power is transmitted to the clutch member during movement to the upshift side. Accordingly, shifts can be performed in both directions with a light operating force even in a state in which drive force is applied during riding. Accordingly, the present invention provides an internal hub transmission for a bicycle comprising: a hub axle having an axle axis and a dropout attachment location for retaining the transmission to a dropout of a bicycle frame; a driver rotatably supported relative to the hub axle; an output member rotatably supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; wherein the operation mechanism comprises an elongated control rod having at least a portion that is completely surrounded by the hub axle; wherein the control rod terminates at an end face before a free end of the hub axle; an actuating mechanism mounted on the hub axle inboard of a free end of the hub axle between the dropout attachment location and the driver for moving the operation mechanism in the direction of the axle axis; and wherein the actuating mechanism extends through a radially outer surface of the hub axle at a location outside the output member and presses against the end face of the control rod in the direction of the axle axis. With reference to the accompanying drawings, in which Figure 1 is a side view of a bicycle in which an embodiment of the present invention is employed; Figure 2 is a vertical cross section of the structure of the internal shifter hub thereof; Figure 3 is an enlarged detail view of the downshift position of this internal shifter hub; Figure 4 is an oblique detail view of the operation mechanism; Figure 5 is a schematic of the relation between the shift key and the cam surface; Figure 6 is a cross section of the lateral portion of the push rod; Figure 7 is a diagram corresponding to Figure 3 of the direct drive position of the internal shifter hub; Figure 8 is a diagram corresponding to Figure 3 of the upshift position of the internal shifter hub; Figure 9 is a diagram corresponding to Figure 3 of Embodiment 2; and Figure 10 is a diagram corresponding to Figure 3 of Embodiment 3. Key: 2 frame body 7 rear wheel 21 hub axle 21b through-groove 21c guide surface 22 driver 23 hub shell 24 planet gear mechanism 25 operation mechanism 32 hub cog 40 sun gear 41 gear frame 42 planet gear 43 ring gear 45 clutch member 47 cam surface 47c inclined surface 48 and 48a push rods 49 and 49a shift keys 50 to 52 first to third one-way clutches 60 to 62 first to third coil springs 65 operator 66 actuator WE CLAIM: 1. An internal hub transmission for a bicycle comprising: a hub axle having an axle axis and a dropout attachment location for retaining the transmission to a dropout of a bicycle frame; a driver rotatably supported relative to the hub axle; an output member rotatably supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; wherein the operation mechanism comprises an elongated control rod having at least a portion that is completely surrounded by the hub axle; wherein the control rod terminates at an end face before a free end of the hub axle; an actuating mechanism mounted on the hub axle inboard of a free end of the hub axle between the dropout attachment location and the driver for moving the operation mechanism in the direction of the axle axis; and wherein the actuating mechanism extends through a radially outer surface of the hub axle at a location outside the output member and presses against the end face of the control rod in the direction of the axle axis. 2. The internal hub transmission as claimed in claim 1 further comprising a biasing member for biasing the operation mechanism in one direction of the axle axis, and wherein the actuating mechanism moves the operation mechanism in an opposite direction of the axle axis. 3. The internal hub transmission as claimed in claim 1 wherein the hub axle includes a groove for exposing the operation mechanism, and wherein the actuating mechanism extends into the groove. 4. The internal hub transmission as claimed in claim 3 wherein the groove is disposed entirely inboard of the free end of the hub axle. 5. The internal hub transmission as claimed in claim 1 wherein the actuating mechanism is swingably mounted to the hub axle. 6. The internal hub transmission as claimed in claim 5 wherein the actuating mechanism comprises: a support member mounted to the hub axle; a link member swingably supported to the support member at an intermediate location of the link member. 7. The internal hub transmission as claimed in claim 6 wherein the link member includes: a first arm member extending from the intermediate portion for connecting to a control cable; and a second arm member extending from the intermediate portion for contacting the operation mechanism. 8. The internal hub transmission as claimed in claim 7 further comprising a link shaft pivotably supporting the intermediate portion of the link member to the support member. 9. The internal hub transmission as claimed in claim 6 wherein the support member includes a stop component for stopping an outer casing of a control cable. 10. The internal hub transmission as claimed in claim 6 wherein the support member defines an opening for exposing the free end of the hub axle. -32- 11. The internal hub transmission as claimed in claim 10 wherein the hub axle extends through the support member. 12. The internal hub transmission as claimed in claim I wherein the output member comprises a hub shell with a flange for supporting a plurality of spokes. 13. An internal hub transmission for a bicycle comprising: a hub axle having an axle axis for retaining the transmission to a bicycle frame; a driver rotatably supported relative to the hub axle; an output member rotatable supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; wherein the operation mechanism comprises an elongated control rod having at least a portion that is completely surrounded by the hub axle; wherein the control rod terminates at an end face before a free end of the hub axle; an actuating mechanism swingably mounted on the hub axle inboard of a free end of the hub axle for moving the operation mechanism in the direction of the axle axis; wherein the actuating mechanism extends through a radially outer surface of the hub axle at a location outside the output member and presses against the end face of the control rod in the direction of the axle axis; wherein the actuating mechanism comprises: a support member mounted to the hub axle; and a link member swingably supported to the support member at an intermediate location of the link member; wherein the hub axle comprises a groove for exposing the operation mechanism, and wherein the link member extends into the groove. 14. The internal hub transmission as claimed in claim 13 wherein the groove is disposed entirely inboard of the free end of the hub axle. 15. The internal hub transmission as claimed in claim 13 wherein the link member includes: a first arm member extending from the intermediate portion for connecting to a control cable; and a second arm member extending from the intermediate portion for contacting the operation mechanism. 16. The internal hub transmission as claimed in claim 15 further comprising a link shaft pivotably supporting the intermediate portion of the link member to the support member. 17. The internal hub transmission as claimed in claim 16 wherein the support member defines an opening for exposing the free end of the hub axle. 18. The interna] hub transmission as claimed in claim 17 wherein the hub axle extends through the support member. 19. The internal hub transmission as claimed in claim 18 further comprising a biasing member for biasing the operation mechanism in one direction of the axle axis, and wherein the second arm member moves the operation mechanism in an opposite direction of the axle axis. 20. The internal hub transmission as claimed in claim 19 further comprising a shift key that slides within a second groove formed in the hub axle in response to movement of the control rod in the direction of the axle axis. -id. 21. An internal hub transmission assembly for a bicycle comprising: a rear dropout of a bicycle frame; a hub axle retained to the rear dropout and having an axle axis; a driver rotatably supported relative to the hub axle; an output member rotatably supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; and an actuating mechanism mounted on the hub axle inboard of a free end of the hub axle between the rear dropout and the driver, wherein the actuating mechanism moves in the direction of the axle axis for moving the operation mechanism in the direction of the axle axis.

Full Text

The present invention relates to an internal hub transmission for a bicycle, and more particularly to a bicycle internal shifter hub that can be mounted to the frame of the bicycle and that transmits the power from an input member to an output member at a specific selected gear ratio.
Bicycles, particularly recreational bicycles referred to as city cruisers, are inexpensive and are easy to ride, and are thus widely used to commute to work or school or for shopping. With this type of recreational bicycle, an internal hub transmission is sometimes mounted at the rear wheel in order to ride at high speeds over flat terrain or to ride uphill with minimal exertion.
An internal shifter hub generally comprises a hub axle that is fixed to the bicycle frame; a hub shell that is able to rotate around the hub axle a planet gear mechanism that is housed in the hub shell; a clutch mechanism for selecting a plurality of drive transmission paths with an interposed planet gear mechanism; and a bell crank for moving the clutch member. The clutch mechanism has a clutch member for switching the drive transmission path by moving in the axial direction, and a push rod that presses this clutch member. The bell crank is linked via a shift cable to a shift lever mounted to the handle bar, for example, in order to control shifts.
With this internal shifter hub, operation of the shift lever winds and pulls the inner cable of the shift cable, causing the bell crank to push on the push rod, moving the clutch member in one axle direction, and performing a gear shift from a

higher to a lower speed step. However, when the inner cable is slackened, the clutch member cannot be moved to the other side with the push rod atone. Therefore, the energizing force of a return spring or the like is utilized to move the clutch member in the other axial direction, and perform a gear shift from a lower to a higher speed step, for example.
[0005]
Problems Which the Invention is Intended to Solve
With the conventional internal shifter hub described above, when the bicycle is pedaled and a large drive force is applied, a large amount of resistance is generated between the clutch member and the parts that make up the planet gear mechanism. Specifically, when a drive force is applied, frictional force increases in the engaged portions between the clutch member and the parts that make up the planet gear mechanism, and this makes it more difficult for the gears to be shifted by movement of the clutch.member.
[ 0006 ] In order to prevent this, the clutch member must be pushed with enough
force to overcome the frictional force when the inner cable is pulled and [the clutch' member is] pushed with the push rod, which means that more strength is required when the inner cable is wound. Also, the spring force of the return spring must be large enough to overcome the frictional force when the inner cable is slackened and the clutch member is returned by the return spring. If the spring force of the return spring is increased, however, then the push rod will have to be pushed at a force greater than this spring force, so greater force will be required when the inner cable is wound by the shift lever.
[ 0007 ] Consequently, in order to allow the gears to be shifted in a state in
which a drive force is applied during riding regardless of the direction of the shift, greater strength is needed to operate the shift lever. For this reason, in the case of an internal shifter hub, it is difficult to perform a gear shift with a light operating force in a state in which a drive force is applied during the pedaling of the bicycle.
An object of the present invention is to allow a shift to be made in either direction and with a light operating force in an internal shifter hub, even when a drive force is applied during riding.

[0008]
Means Used to Solve the Above-Mentioned Problems
The internal shifter hub pertaining to the first invention is a hub which can be mounted to the frame of the bicycle, with which the power from an input member is transmitted to an output member at the selected specific gear ratio, and which comprises a hub axle, a driver, a tubular follower, a planet gear mechanism, a first one-way clutch, second and third one-way clutches, a tubular clutch member, and a clutch control component. The hub axle can be fixed to the frame. The driver can be rotated around the hub axle and can be linked to the input member. The follower has a housing space in its interior, can be rotated around the hub axle, and can be linked to the output member. The planet gear mechanism is disposed inside the housing space of the follower, has a sun gear disposed coaxially with the hub axle, a planet gear that meshes with the sun gear, a gear frame that rotatably supports the planet gear and that can be rotated around the hub axle, and a ring gear that can be rotated around the hub axle and meshes on the outside with the planet gear, and transmits the power from the driver to the follower. The first one-way clutch is disposed between the ring gear and follower, can transmit power in only one direction, and can switch between a power transmission state and a power cut-off state in a power transmittable state. The second and third one-way clutches are respectively disposed between the driver and ring gear and between the gear frame and follower, and transmit power in only one direction. The clutch member is provided to the hub axle such that it can rotate and can move in the axial direction, switches the driver and gear frame between a linked state and a disengaged state by moving in the axial direction, and switches the first one-way clutch between a power transmission state and a power cut-off state. The clutch control component moves the clutch member in the axial direction, and engages with the clutch member so as to allow the rotational drive force of the clutch member to be converted into displacement in the axial direction.
[ 0009 ] With this internal shifter hub, when the input member is rotated in one
direction by disposing the clutch member in a downshift position that separates the driver and the gear frame with the clutch control component, and puts the first one-way clutch in a power cutoff state, the rotation thereof is transmitted to the ring gear via the driver and the second one-way clutch, and is outputted from the gear frame via the planet gear mechanism, reduced by (number of teeth on the ring gear) ■*■ (number of teeth on the sun gear + number of teeth on the ring gear). This reduced rotation is transmitted through the third one-way clutch from the gear frame to the follower, and the output member rotates at reduced speed in one direction.

[ 0010 ] When the input member is rotated in one direction by disposing the
clutch member in a direct drive position that separates the driver and the gear frame with the clutch control component, and puts the first one-way clutch in a power transmission state, the rotation is transmitted to the ring gear via the driver and the second one-way clutch, the rotation of the driver is directly transmitted to the follower via the first one-way clutch, and the output member is rotated at the same speed in one direction.
£.0011 ] When the input member is rotated in one direction by disposing the
clutch member in an upshift position that puts the driver and the gear frame in a direct-link state with the clutch control component, and puts the first one-way clutch in a power transmission state, the rotation thereof is transmitted to the gear frame via the driver and the clutch member, and is outputted from the ring gear via the planet gear mechanism, increased by (number of teeth on the sun gear + number of teeth on the ring gear) + (number of teeth on the ring gear). This increased rotation is transmitted through the first one-way clutch from the ring gear to the follower, and the output member rotates at increased speed in one direction.
[ 0012 ]- Here, when the clutch member is moved from a downshift position to an
upshift position via a direct drive position, even if rotation is transmitted to the clutch member, the clutch member will merely freewheel, and the rotational force will not be transmitted, so only a little strength is required to move the clutch member in this direction. Meanwhile, when the clutch member is moved from an upshift position to a direct drive position, friction between the clutch member and the gear frame makes it more difficult for the clutch member to separate from the gear frame, and when the clutch member is moved from a direct drive position to a downshift position, the drive force is applied to the first one-way clutch that links the gear frame to the hub shell, so it becomes more difficult to cut off the power. However, if the clutch control component is engaged with the clutch member, the rotational drive force of the clutch member is converted into displacement in the axial direction, an assist force is generated, and the clutch member makes use of the rotational drive force of the bicycle, facilitating movement in the axial direction. Accordingly, less strength is required to move the clutch member from an upshift position to a downshift position. Therefore, gear shifts can be performed in either direction with a light operating force even if a drive force is applied during riding.
[ 0013 ] The bicycle internal shifter hub pertaining to the second invention is the
hub defined in the first invention, wherein the clutch control component has a guide surface provided to the hub axle, a shift key for moving the clutch member in the axial

direction by moving along the guide surface, and a pressing member that presses the shift key, and the clutch member is able to strike the shift key, and has a cam surface, which is inclined with respect to the axis of the hub axle, for converting rotational drive force into displacement in the axial direction by rotation in one direction when striking the shift key.
[ 0014"] Here, when the shift key strikes the cam surface of the clutch member,
the shift key rides up onto the cam surface as a result of the rotation of the clutch member in one direction, and the rotational drive force is converted into displacement in the axial direction of the clutch member. Accordingly, the rotational drive force can be converted into displacement in the axial direction with a simple construction.
The bicycle internal shifter" hub pertaining to the third invention is the hub defined in the second invention, wherein a through-groove that goes through the axis of the hub axle and is twisted in a spiral to the opposite side from the one direction is formed in the hub axle, and the guide surface is part of the surface that forms the through-groove, and is provided such that it is inclined by a specific groove inclination angle with respect to the axis of the hub axle.
[ 0015 ] In this case, since the guide surface of the through-groove is inclined
with respect to the axis and is twisted in a spiral to the opposite side from the one direction, when the clutch member rotates in the one direction and the shift key rides up onto the cam surface, the shift key is pressed toward the guide surface by the cam surface along the entire length in the contact portion with the guide surface, and it is more difficult for the shift key to escape in the axial direction than for the clutch member. Furthermore, when an extremely large drive force is applied, the shift key, rather than the clutch member, will escape in the axial direction, so no shift will be performed in a state in which the drive force is extremely large, shifting shock will be reduced, and damage to the power transmission mechanism portion in the interior caused by excessive drive force will be prevented.
[ 0016 ] The bicycle internal shifter hub pertaining to the fourth invention is the
hub defined in the third invention, wherein the groove inclination angle is within a range of 10 to 50 degrees. If the groove inclination angle is less than 10 degrees, the shift key will tend to escape in the axial direction when pressed against the cam surface. If 50 degrees is exceeded, however, there will be a large amount of resistance when the shift key is pressed by the pressing member, and greater operating force will be needed to make a shift.
[ 0017 ] The bicycle internal shifter hub pertaining to the fifth invention is the
hub defined in the third or fourth invention, wherein the inclination angle of the clutch

member with respect to the hub axle axis of the cam surface is greater than the groove inclination angle, and is between 20 and 70 degrees. Making the inclination angle of the cam surface greater than the groove inclination angle results in the angle of the guide surface at which the shift key actually moves being less than [that of] the cam surface when the shift key strikes the clutch member, so the shift key can move away from the cam surface. If the inclination angle is less than 20 degrees, the inclination will be too steep, and the rotational drive force cannot be converted efficiently into displacement in the axial direction, but if 70 degrees is exceeded, the slope will be too gentle, sufficient displacement in the axial direction will not be obtained, and even if the rotational drive force is converted into displacement in the axial direction, the clutch member will have difficulty separating from the gear frame, and it will be difficult to move the first one-way clutch from a power transmission state to a power cutoff state.
[ 0018 ] The bicycle internal shifter hub pertaining to the sixth invention is the
hub defined in the fourth or fifth invention, wherein the shift key has a triangular cross
section and is disposed inside the through-groove such that the lengthwise direction
thereof extends perpendicular to the hub axle. In this case, movement in the twisted
through-groove is possible by means of a shift key with a simple shape, and movement
in the through-groove can be restricted by frictional force. Specifically, when the cam
surface strikes one of the triangular surfaces of the shift key, [the shift key] is pressed
by the cam surface, the other surface comes into contact with the guide surface, and
friction makes it difficult for the shift key to move in the axial direction. During the
movement [of the shift key] produced by the pressing member, only one surface is in
contact, and the other surface is not, so there is less resistance during movement.
[ 0019 ] The bicycle internal shifter hub pertaining to the seventh invention is the
hub defined in any of the second to sixth inventions, further comprising a first
energizing member for energizing the clutch member to the gear frame side, a second
energizing member for energizing the shift key to the clutch member side, and a third
energizing member that is interposed between the shift key and clutch member, and is
for energizing these two components in opposite directions by elastic force prior to the
striking of the clutch member by the shift key when striking the two.
[ 0020 ] Here, since the clutch member is energized to the gear frame side by the
first energizing member, when the clutch member is linked to the gear frame during the movement of the clutch member to the upshift side, even if the two are not in the linked position, they can be reliably linked by rotation of the clutch member. Also, since the shift key is energized to the clutch member side by the second energizing

member, the clutch member can be reliably moved to the downshift side when the clutch member moves to the downshift side. Furthermore, since the shift key and the clutch member are energized away from each other by the third energizing member, even if the shift key strikes the cam surface during a downshift, the shift key and the cam surface will separate from one another if the clutch member separates from the gear frame. Accordingly, the cam surface does not strike the shift key during riding, and no striking noise is generated.
[ 0021 ] The bicycle internal shifter hub pertaining to the eighth invention is the
hub defined in the seventh invention, wherein the third energizing member is a coil spring restricted to a specific overall length. In this case, the energizing force can be set for when the shift key strikes the clutch member. This means that when the separation resistance is not large, the gap between the shift key and the clutch member is the same as the set length of this energizing member, so the clutch member can be positioned more accurately.
[ 0022 ] The bicycle internal shifter hub pertaining to the ninth invention is the
hub defined in the seventh or eighth invention, wherein the pressing member presses the shift key to the gear frame side. In this case, in a state in which the shift key is not pressed, the clutch member is disposed in a downshift position, and as [the shift key] is pressed, it moves from a direct drive position to an upshift position.
The bicycle internal shifter hub pertaining to the tenth invention is the hub defined in the ninth invention, wherein the pressing member is a rod-like member, and the energizing forces of the three energizing members are set such that the second energizing member is strongest, the third energizing member is weaker, and the first energizing member is weakest. In this case, when the pressing member is retracted to the opposite side from the pressing side, the energizing force of the second energizing member is greater than that of the other energizing members, so the clutch member can be moved by means of the second energizing member. Furthermore, since the energizing force of the third energizing member is greater than that of the first energizing member, the shift key will not readily strike the clutch member when the shift key is pressed by the pressing member so that the clutch member is moved to the upshift side by the first energizing member.
[ 0023 ] The bicycle internal shifter hub pertaining to the eleventh invention is
the hub defined in the ninth invention, wherein the pressing member has a rod-like controller of a specific length, an actuator mounted so as to allow relative motion in the axial direction at the distal end of the controller, and an energizing member that is interposed between the controller and actuator and that energizes the two in opposite

directions, wherein the shift key is able to press the clutch member in both axial
directions, and the energizing member is the first energizing member, and the
energizing forces are set such that the first energizing member is strongest, the second
energizing member is weaker, and the third energizing member is weakest.
[ 0024 ] In this case, the shift key can be moved to the upshift side against the
energizing force of the second energizing member because the energizing force of the
first energizing member is greater than that of the second energizing member when the
shift key is pressed by the pressing member so that the clutch member is moved from
the downshift side to the upshift side. As a result, the shift key presses on the clutch
member, and the clutch member moves to the upshift side. When the pressing member
is retracted to the opposite side from the pressing side, the energizing force of the
second energizing member is greater than that of the third energizing member, so the
clutch member can be moved by means of the second energizing member.
Furthermore, since the first energizing member, which has the greatest energizing
force, is interposed in the pressing member, the number of coiis can be increased, and
the spring constant can be reduced. As a result, the spring constant of the other
energizing members can be further reduced, allowing a reduction in the operating force
of the shift operation as a whole. Also, since the energizing force of the second
energizing member is greater than that of the third energizing member, the shift key
can be reliably made to strike the clutch member at the point when assist force is
required during movement to the downshift side by the first energizing member.
[ 0.025 ] The bicycle internal shifter hub pertaining to the twelfth invention is the
hub defined in the seventh or eighth invention, wherein the pressing member presses the shift key to the clutch member side. In this case, in a state in which the shift key is not pressed, the clutch member is disposed in an upshift position, and moves from a direct drive position to a downshift position as it is pressed.
The bicycle internal shifter hub pertaining to the thirteenth invention is the hub defined in the twelfth invention, wherein the pressing member has a rod-like controller of a specific length, an actuator mounted so as to allow relative motion in the axial direction at the distal end of the controller, and an energizing member that is interposed between the controller and actuator and that energizes the two in opposite directions, wherein the shift key is able to press the clutch member in both axial directions, and the energizing member is the second energizing member, and the energizing forces are set such that the second energizing member is strongest, the third energizing member is weaker, and the first energizing member is weakest.

[ 0026 ] In this case, the shift key can move to the downshift side against the
energizing force of the first energizing member because the energizing force of the second energizing member is greater than that of the first energizing member when the shift key is pressed by the pressing member so that the clutch member is moved from the upshift side to the downshift side. As a result, the shift key presses on the clutch member, and the clutch member moves to the downshift side. Also, since the energizing force of the second energizing member is greater than that of the third energizing member, the shift key can reliably strike the clutch member when an assist force is needed during movement to the downshift side. Meanwhile, when the pressing member is retracted to the opposite side from the pressing side and the clutch member is pressed by the first energizing member, the energizing force of the third energuing member is greater than that of the first energizing member, so the clutch member can be moved to the upshift side in a state in which the clutch member and the shift key are separated by the third energizing member.
10027']
Embodiments of the Invention
Embodiment 1
Overall Structure: In Figure 1, the bicycle in which an embodiment of the
present invention has been employed is a recreational bicycle, which comprises a
frame 1 having a double-loop type of frame body 2 and a front fork 3, a handle
component 4,'a drive component 5, a front wheel 6, a rear wheel 7 to which a three-
speed internal shift hub 10 has been mounted, a front braking apparatus 8, and a gear
shifter component 9 for operating the internal shift hub 10 close at hand.
[ 0028 ] Various components including a saddle 11, the handle component 4, the
front wheel 6, and the rear wheel 7 are attached to the frame 1.
The handle component 4 has a handle stem 14 fixed to the upper portion of the front fork 3, and a handlebar 15 fixed to this handle stem 14. A brake lever 16, which constitutes part of the front brake apparatus 8, a grip 17, and the gear shifter component 9 are mounted at the right end of the handlebar 15. The gear shifter component 9 is mounted on the brake lever 16 on the inside of the brake lever 16, and is linked with an internal shifter hub 10 by means of a shift control cable 73 comprising an inner cable and an outer cable. The gear shifter component 9 has an ordinary structure having a winding lever for winding the inner cable, and a release lever that

releases the winding operation of the winding lever and plays out the inner cable, and as such will not be described in detail herein.
[ 0029 ] The drive component 5 has a gear crank 18 that is provided to the lower
portion (bottom bracket portion) of the frame body 2, a chain 19 that goes around the gear crank 18, and the internal shifter hub 10.
Structure of the Internal Shifter Hub
The internal shifter hub 10 is a coaster brake-equipped hub with a three-stage structure including power transmission paths for downshifting, direct drive, and upshifting. As shown in Figure 2, this internal shifter hub 10 has a hub axle 2] fixed to the rear pawl 2a of the frame body 2 of the bicycle, a driver 22 disposed around the outer periphery at one end of the hub axle 21, a hub shell 23 disposed further around the outer periphery of the hub axle 21 and the driver 22, a planet gear mechanism 24, an operation mechanism 25 for selecting a power transmission path, a bell crank 26 for actuating the operation mechanism 25, and a coaster brake 27.
[ 0030 ] As shown in Figures 2 and 3, the hub axle 21 is a rod-like member
which has a larger diameter in its middle and a smaller diameter at both ends, and on which threads are formed at both ends. An operation hole 21a is formed in the axial portion of the hub axle 21 from the right end to the center in Figure 2. A through-groove 21b that goes through the axis is formed in the vicinity of the bottom of the operation hole 21a. The through-groove 21b goes through the axis of the hub axle 21 and is inclined by a specific groove inclination angle p (see Figure 5) with respect to the axis, and is formed in a twist to the side opposite the forward direction going from the right to the left in Figure 5. This through-groove 21b is formed by using an end drill of a specific diameter to form holes that go through the axis, and then feeding [the drill] toward the center in the axial direction while the hub axle 21 is slowly rotated in the forward direction. Therefore, this through-groove 21b is shaped as a continuous spiral in which the through-holes intersecting at both ends rotate gradually according to movement in the axial direction. This groove inclination angle |3 should range from 10 to 50 degrees.
[ 0031 ] One end of the driver 22 is rotatably supported on the hub axle 21 via
balls 30 and a hub cone 31, and a hub cog 32 is fixed around the outer periphery at one end. A plurality of serration inner teeth 22a are formed in the axial direction around the inner periphery at the other end of the driver 22.
The hub shell 23 is a tubular member, and a housing space 23a around the inner periphery thereof houses the driver 22 and the planet gear mechanism 24. The hub

shell 23 is able to rotate around the hub axle 21 via balls 33 and 34 and a hub cone 35. Hubs 36 and 37 for supporting spokes 7a (see Figure 1) are fixed at both ends of the outer periphery of the hub shell 23.
[0032]
Structure of the Planet Gear Mechanism
The planet gear mechanism 24 has a sun gear 40 formed coaxially and integrally with the hub axle 21, a gear frame 4.1 disposed around the outer periphery of the hub axle 21, three planet gears 42 (only one planet gear is shown in the figure) that mesh with the sun gear 40, and a ring gear 43.
[ 0033 ] The gear frame 41 is a tubular member, and is rotatably supported on
the hub axle 21. Three notches 41a are formed in the circumferential direction in the gear frame 41, and the planet gears 42 are rotatably supported by pins 44 in these various notches 41a. Serration inner teeth 41b are formed around the inner periphery at one end of the gear frame 41, and serration outer teeth 41c (Figure 1) are formed around the outer periphery at the other end.
[ 0034 ] The ring gear 43 is formed in a nearly cylindrical shape, and extends
from the planet gears 42 to the outer periphery of the driver 22. Inner teeth 43b are formed around the inner periphery at the other end of the ring gear 43. The planet gears 42 mesh with the sun gear 40 as mentioned above, but at the same time also mesh with the inner teeth 43b of the ring gear 43.
A notch 43a is formed at one end of the ring gear 43, and a clutch pawl 53 that
makes up part of a first one-way clutch 50 as shown in Figure 4 is swingably supported
by a pin 54 in'this notch 43a. This clutch pawl 53 is energized in the standing
direction by a torsion coil spring 55. The first one-way clutch 50 transmits only
rotational drive force in the forward direction from the ring gear 24 [sic] to the hub
shell 23. The clutch pawl 53 meshes with the ratchet teeth 23b formed on the inner
peripheral surface of the hub shell 23 only when the ring gear 24 [sic] has rotated in the
forward direction. Even when in a transmission-enabled state in which the ring gear 24
[sic] rotates in the forward direction, this first one-way clutch 50 is able to switch
between a power transmission state in which the clutch pawl 53 meshes with the ratchet
teeth 23b, and a transmission cutoff state of retraction from the ratchet teeth 23b,
which is accomplished by the movement of the clutch member as discussed below.
[ 0035 ] A second one-way clutch 51 that transmits rotational drive force only in
the forward direction from the driver 22 to the ring gear 24 [sic] is arranged between the driver 22 and the ring gear 24 [sic], A third one-way clutch 52 that transmits

rotational drive force only in the forward direction from the gear frame 41 to the hub shell 23 is arranged between the gear frame 41 and the hub shell 23. The third one-way clutch 52 has a tubular clutch case 56 in which serration inner teeth 56a are formed around the inner periphery at one end. These serration inner teeth 56a engage with the serration outer teeth 41c of the gear frame 41, and the clutch case 56 rotates integrally with the gear frame 41. These two one-way clutches 51 and 52 are unable to perform switching in a transmission-enabled state, unlike the First one-way clutch 50.
[0036]
Structure of the Operation Mechanism
The operation mechanism 25 is used to select the power transmission path, and has a clutch member 45 and a clutch control component 46.
The clutch member 45 switches the driver 22 and gear frame 41 between a linked state and a separated state, and also switches the first one-way clutch 50 between a power transmittable state and a power cutoff state. The clutch member 45 is positioned around the outer periphery of the hub axle 21 such that it can move and rotate in the axial direction.
[ 003? J The clutch member 45 is a tubular member as shown in Figure 4, and
has serration outer teeth 45a formed around the outer periphery at one end thereof. The serration outer teeth 45a are slidably engaged with the serration inner teeth 22a. A large diameter component 45b is formed at the other end of the clutch member 45, and serration outer teeth 45c are formed around the outer periphery thereof. The serration outer teeth 45c are able to engage with the serration inner teeth 41b formed on the gear frame 41. A Taper surface 45d is formed between the large diameter component 45b and one end. This taper surface 45d is provided in order to lower the clutch pawl 53 of the first one-way clutch 50 from its erected position (power transmission position) indicated by the solid line to its retracted position (power cutoff position) indicated by the two-dot chain line. When the clutch member 45 moves from the left to the downshift position on the right end, the clutch pawl 53 follows along the taper surface 45d, rides up onto the large diameter component 45b, and is lowered into a retracted attitude.
[ 0038 ] As shown in Figure 3, two step components 45e and 45f are formed
around the inner periphery of the clutch member 45 with spaces between them in the axial direction. As shown in Figure 4, a plurality of cam surfaces 47 are formed on the left step component 45f with spaces between them in the circumferential direction. As shown in Figure 5, the cam surfaces 47 have a flat surface 47a that is depressed at one

end, a curved surface 47b that leads downstream in the forward direction A of the flat
surface 47a, and an inclined surface 47c that leads upstream. The inclination angle a
with respect to the axis of this inclined surface 47c should be greater than the groove
inclination angle P of the through-groove 21b, and between 20 and 70 degrees.
'E-0039 ] The clutch control component 46 moves the clutch member 45 in the
axial direction of the hub axle 21, and engages with the clutch member 45 to convert the rotational drive force of the clutch member 45 into displacement in the axial direction. The clutch control component 46 has a push rod 48 that moves in the axial direction through the operation hole 21a, and a shift key 49 that is pressed to the gear frame 41 side by the push rod 48, as shown in Figure 3.
•4J-9040 }■ ■ As shown in Figure 6, the push rod 48 has an operator 65 of a specific length, an actuator 66 that is mounted on the distal end of the operator 65 such that the former can move in the axial direction, and a first coil spring 60 that is positioned between the operator 65 and the actuator 66. The operator 65 has a rod component 68 and a strike component 69 threaded onto the rod component 68. A threaded component 68a is formed on the base end of the rod component 68, and a large diameter component 68b is formed on the distal end. This threaded component 68a is threaded into the strike component 69. The large diameter component 68b is slidably mounted in a guide hole 66a formed in the interior of the actuator 66. The guide hole 66a has a smaller diameter on the actuator 66 side, which keeps the actuator 66 from coming out. The first coil spring 60 is inserted in a compressed state between the end surface of the actuator 66 and the end component of the strike component 69, and energizes the actuator 66 and the operator 65 away from each other, so that when the actuator 66 presses on the shift key 49, the clutch member 45 is energized to the gear frame 41 side.
-t-QtWH,,, As shown in Figure 4, the shift key 49 is a rod-like member with a triangular cross section, and when pressed, moves through the through-groove 21b while turning in the opposite direction from the forward direction, that is, while twisting. The contact surface 49b of the shift key 49 onto the through-groove 21b is formed at an angle that follows the through-groove 21b. For example, when the groove inclination angle p of the through-groove 21b is 30 degrees, the angle of the contact surface 49b with respect to the axis is also about 30 degrees. The outward movement of the shift key 49 is restricted to within the clutch member 45 by a stop ring 63 mounted around the inner periphery at the other end of the clutch member 45. Therefore, [the shift key 49] cannot actually come out of the clutch member 45 as

shown in Figure 4. As a result, the shift key 49 is pressed by the push rod 48 and moves the clutch member 45 to the left in Figure 3.
[ 0042 }• The shift key 49 is able to strike the cam surfaces 47 inside the clutch
member 45. If the clutch member 45 is rotated in the forward direction in a state in
which the shift key 49 has struck the fiat component 47a of the cam surface 47, then
the shift key 49 is pressed to the guide surface 21c side of the through-groove 21b by
the inclined surface 47c of the cam surface 47, and its motion to the left in the axial
direction is restricted, so the clutch.member 45 moves to the right in the axial
direction. Specifically, the rotational drive force of the clutch member 45 is converted
into displacement in the axial direction to assist shift control.
£-9043 ]" A notch 49a is formed at both ends of the shift key 49, and in this
notch 49a is stopped a second coil spring 61 that is stopped at one end on the hub axle 21. The shift key 49 is constantly energized to the clutch member 45 side by this second coil spring 61. A third coil spring 62 is interposed between the shift key 49 and the clutch member 45. The third coil spring 62 is restricted to a specific overall length by a restricting member (not shown), and when compressed, energizes the shift key 49 and the clutch member 45 away from each other before the former strikes the latter. As a result, the clutch member 45 remains at a constant distance from the shift key 49 during movement, and is accurately positioned.
f-6©44^~ Here, the energizing forces of the first through third coil springs 60, 61, and 62 decrease in that order. Specifically, the spring forces decrease in that order. Here, if the spring force of the first coil spring 60 is less than that of the second coil spring 61, then even if the shift key 49 is pressed by the push rod 48, the first coil spring 60 will bend and the shift key 49 will not move. If the spring force of the second coil spring 61 is less than that of the third coil spring 62, then even if the shift key 49 is pressed by the second coil spring 61, the shift key 49 will not go into the cam surface 47, and shift control cannot be assisted.
f-0Q45 ] The first coil spring 60 is positioned in a relatively large space between
the operator 65 and the actuator 66 inside the operation hole 21a, so it is possible to increase the number of coils and thereby lower the spring constant and the spring force. Accordingly, the spring constants and spring forces of the second and third coil springs 61 and 62 can be further lowered, allowing a reduction in the force required to press the push rod 48 during an upshift, that is, the operating force of the winding lever in the shift control component 9. As a result, there is less tension on the inner cable, and the inner cable does not break as frequently.

Structure of the Bell Crank
The bell crank 26 is mounted at the axial end of the hub axle 21. The bell crank 26 comprises a support bracket 70 mounted at the axial end, and a link member 71 swingably supported by the support bracket 70. The outer casing 73a of a shift control cable 73 is stopped at this support bracket 70, and an inner cable 73b is stopped at the link member 71. The distal end of the link member 71 strikes the base end of the push rod 48. Here, pulling the inner cable 73b by means of the shift control component 9 swings the link member 71, presses the push rod 48, and executes an upshift. When the inner cable is slackened, the clutch member 45 is pressed by the second coil spring 61 via the shift key 49, and a downshift is executed.
-£0047]
Structure of the Coaster Brake
As shown in Figure 1, the coaster brake 27 is mounted to the brake case 56. The coaster brake 27 comprises a brake roller 57 supported by the brake case 56, a cam surface 41d formed around the outer periphery at the other end of the gear frame 41, and a brake shoe 58 that exerts a braking action on the inner surface at the other end of the hub shell 23. The brake roller 57 is designed such that it is pushed outward in the radial direction by the cam surface 41d when the driver 22 rotates in the reverse direction. As a result, the brake shoe 58 comes into contact with and brakes the inner surface of the hub shell 23.
' [ 0048 ] " Brake lock tends to occur when the coaster brake 27 is installed. Brake lock is a phenomenon whereby, if the first one-way clutch 50 is in a power transmission state when the rider pedals backward to brake, the drive force will be transmitted in a state in which the brake is applied, and the brake cannot be released. A pawl cage 59 is mounted to the first one-way clutch 50 in this embodiment in order to prevent this phenomenon.
^0049^- The pawl cage 59 provides a specific angle of play between the ratchet teeth 23b of the hub shell 23 and the clutch pawl 53 of the first one-way clutch 50, and allows the brake to be released while the ring gear 43 rotates by this amount of play. Specifically, the pawl cage 59 either prevents the clutch pawl 53 from being erected at a specific angle, or, even if it is erected, allows it to be erected at a position where it
' Translator's note: "56" is referred to as a "clutch case" above; possible error.

cannot stop the ratchet teeth 23b at the specific angle, and delays the time when the clutch pawl 53 is stopped by the ratchet teeth 23b during initial drive.
[•0050-3-
Shift Actuation
Because of this planet gear mechanism 24 and one-way clutches 50 to 52, this internal shifter hub 10 has:
a downshift power transmission path made up of the driver 22, the ring gear 43, the planet gear mechanism 24, the gear frame 41, and the hub shell 23;
a direct drive power transmission path made up of the driver 22, the ring gear 43, and the hub shell 23, and
an upshift power transmission path made up of the driver 22, the clutch member 45, the gear frame 41,' the planet gear mechanism 24,2 the ring gear 43, and the hub shell 23.
[ 0051-j- Shifting is performed by operating the push rod 48 with the bell crank 26
via the shift control cable 73.
Down shift-Upshift Actuation
In the state shown in Figure 3, in which the push rod 48 is not pushed in, the
clutch member 45 is disposed in the downshift position at the right end, and the
rotation from the driver 22 is transmitted to the hub shell 23 after being reduced in speed
via the downshift power transmission path. Specifically, the rotation inputted to the
driver 22 is transmitted to the ring gear 43 via the second one-way clutch 51. At this
point, the clutch pawl 53 of the first one-way clutch 50 is rotated by the clutch
member 45 to the retracted attitude shown by the two-dot chain line in Figure 4, and
the first one-way clutch 50 is in a power cutoff state. Accordingly, the rotation
transmitted to the ring gear 43 is further transmitted to the hub shell 23 via the planet
gear mechanism 24, the gear frame 41, and the third one-way clutch 52. In this case,
the inputted rotation is reduced in speed according to the gear shift ratio determined by
the numbers of teeth of the sun gear 40, the planet gears 42, and the ring gear 43.
[-00-5 2-j Meanwhile, if the winding lever of the shift control component 9 is
operated, the link member 71 of the bell crank 26 swings and pushes in the push rod 48 by one stage. As a result, since the spring force of the first coil spring 60 is greater
Translator's note: "71" in the original; probable typo. " Translator's note: "54" in the original; probable typo.

than the spring force of the second coil spring 61, the shift key 49 is pushed by the link member 71 via the push rod 48, guided into the through-groove 21b, and moved to the left in Figure 3 while rotating around the hub axle, and the clutch member 45 is also pushed via the stop ring 63, and moves to-the direct drive position. Once the clutch member 45 is disposed in the direct drive position shown in Figure 7, the clutch pawl 53 of the first one-way clutch 50, which had been put into a retracted attitude by the taper surface 45d, is returned to the erected attitude shown by the solid line in Figure 4 by the spring force of the torsion coil spring 55. In this state, the first one¬way clutch 50 is able to transmit only rotation in the forward direction from the ring gear 43 to the hub shell 23. Therefore, the rotation from the driver 22 is directly transmitted to the hub shell 23 through the direct drive power transmission path. Specifically, the rotation inputted to the driver 22 is transmitted to the ring gear 43 via the second one-way clutch 51, then is transmitted to the hub shell 23 via the first one¬way clutch 50, and the rotation of the driver 22 is transmitted directly to the hub shell 23 via the ring gear 43. At this point, the rotation is transmitted from the ring gear 43 to the gear frame 41 via the planet gear mechanism 24, and the gear frame 41 rotates at reduced speed, but since the rotation of the hub shell 23 is faster than that of the gear frame 41, there is no transmission of the rotation from the gear frame 41 to the hub shell 23 via the third one-way clutch 52.
[-0053 ] When the winding lever is operated from the direct drive state and the
push rod 48 is pushed in further, the shift key 49 moves further to the left, and the clutch member 45 also moves correspondingly to the upshift position. When the clutch member 45 is disposed in the upshift position shown in Figure 8, the serration outer teeth 45c of the clutch member 45 and the serration inner teeth 41b of the gear frame 41 mesh with each other. In this movement to the upshift position, when the serration outer teeth 45c and the serration inner teeth 41b are disposed in the positions where they mesh, the clutch member 45 moves directly to the upshift position to the left after the clutch member 45 strikes the gear frame 41, When, however, [these teeth] are disposed in positions where they do not mesh, the shift key 49 and the clutch member 45 temporarily halt their movement to the left at the point when the clutch member 45 strikes the gear frame 41. When this happens, the actuator 66 of the push rod 48 retracts, the first coil spring 60 is compressed, and the shift key 49 is pressed. When the clutch member 45 then rotates and the two sets of teeth 45c and 41b reach their meshing positions, the spring force of the first coil spring 60 moves the clutch member 45 via the shift key 49, and the two sets of teeth 45c and 41b mesh.

fQQS4-}. in this state, the rotation transmitted to the driver 22 is transmitted to the
hub shell 23 via the upshift transmission path. Specifically, it is transmitted from the driver 22, through the clutch member 45, and to the gear frame 41, and the rotation transmitted to the gear frame 41 is transmitted to the hub sheli 23 via the planet gear mechanism 24, the ring gear 43, and the first one-way clutch 50. In this case, the inputted rotation is increased in speed and outputted according to the gear shift ratio determined by the numbers of teeth of the sun gear 40, the planet gears 42, and the ring gear 43. There is an attempt at this point to transmit the rotation from the driver 22 toward the ring gear 43 via the second one-way clutch 51, but since the rotation of the ring gear 43 is faster than that of the driver 22, no rotation is transmitted from the second one-way clutch 51.
[■0055'] Since rotation is transmitted directly between the driver 22 and the ring
gear 43 during such a shift from the downshift side to the upshift side, it is best to move the clutch member 45, which has no force acting upon it. Accordingly, the spring force of the first coil spring 60 for pushing the clutch member 45 may be reduced, and furthermore, since the spring force of the second coil spring 61 is lower than this, shift operation can be performed with a light force.
Upshift-Downshift Assist Actuation
When the release lever of the shift control component 9 is operated at the upshift position shown in Figure 8, the energizing force of the first coil spring 60 is removed, and the second coil spring 61 presses on the shift key 49 and causes the push rod 48 to retract by one stage to the right. The shift key 49 then presses on the clutch member 45 via the third coil spring 62, and attempts to move the clutch member 45 to the direct drive position. When the rider is not pedaling and no drive force is being transmitted, the clutch member 45 separates from the gear frame 41, and the clutch member 45 moves to the direct drive position. If the rider is pedaling, however, since drive force is being transmitted from the clutch member 45 to the gear frame 41, frictional force may cause the serration inner teeth 41b and the serration outer teeth 45b to remain meshed. In a case such as this, the spring force of the second coil spring 61 alone will not move the clutch member 45 to the right in Figure 8. In a state such as this, when the shift key 49 strikes the flat surface 47a of the cam surface 47 of the clutch member 45 as shown in Figure 5, the shift key 49 is pressed to the guide surface 21c side over the entire length of the portion inserted in the through-groove 21b, and is prevented by frictional force from escaping in the axial direction.

As a result, when the shift key 49 rides up on the inclined surface 47c, the clutch member 45 moves to the right. When the serration inner teeth 41b and the serration outer teeth 45c are then unmeshed, the clutch member 45 is pressed by the second coil spring 61 via the shift key 49 and moves to the direct drive position. Specifically, contact between the cam surface 47 of the clutch member 45 and the shift key 49 assists shifting by converting the rotational motion of the clutch member 45 into displacement in the axial direction.
[-0057 f Here, the shift key 49 cannot readily escape to the left in the axial
direction as mentioned above because it is pressed by the second coil spring 61, and the through-groove 21b is inclined and twisted in a spiral with respect to the axis. Therefore, the shift key 49 will not escape in the axial direction when the transmitted drive force is less than the energizing force of the second coil spring 61 and the frictional force between the shift key 49 and the guide surface 21c. However, when a drive force greater than these is applied, the shift key 49 may overcome the energizing force of the second coil spring 61 and the frictional force with the guide surface 21c and escape to the left in the axial direction without the clutch member 45 moving. The above-mentioned frictional force here can be set by means of the groove inclination angle fi. If this groove inclination angle (3 is set to high, then it will be difficult for the shift key 49 to move to the teft when the shift key 49 is pushed by the push rod 48. If the groove inclination angle (3 is set too low, however, the resistance will be smaller during pushing by the push rod 48, but the frictional force will also decrease. Therefore, this groove inclination angle p should be between 10 and 50 degrees. It is possible to adjust the drive force at the limit where the shift key 49 escapes during assist by adjusting this groove inclination angle p, the inclination angle a of the inclined surface 47c of the cam surface 47, and the spring force of the three coil springs 60 to 62.
f 0058 i MeanwhiJe, even when a drive force Jarger than the set drive force is
applied, and the shift key 49 escapes in the axial direction without the clutch member 45 moving, once the gear crank 18 reaches the vicinity of top dead center or bottom dead center and the drive force decreases, the clutch member 45 will be pressed by the assist force produced by the shift key 49, and will move to the right. Accordingly, a shift will not be performed when an extremely large drive force is applied, such as on a steep hill, which reduces shifting shock and helps prevent damage to the drive force transmission parts, such as the serration teeth and the one-way clutches.

[■©9§9i When the clutch member 45 moves, the shift key 49 is separated from
the cam surface 47 by the third coil spring 62. Accordingly, there will be no noise
generated by contact with the shift key 49 even if the clutch member 45 is rotated. In
the direct drive position shown in Figure 7, rotation is transmitted from the driver 22 to
the hub she!! 23 via the direct drive transmission path, as discussed above.
[-0060 } When the release lever is operated in a state in which the clutch
member 45 is disposed in the direct drive position, the push rod 48 retracts further, and the shift key 49 presses on the clutch member 45. At this point the taper surface 45d of the clutch member 45 comes info contact with the clutch pawl 53 of the first one-way clutch 50 and attempts to lower the clutch pawl 53 from an erected attitude to a retracted attitude. However, because the clutch pawl 53 is transmitting power from the ring gear 43 to the hub shell 23, it is not readily lowered to a retracted attitude by the energizing force of the second coil spring 61 alone. Here again, when the shift key 49 strikes the cam surface 47 of the clutch member 45, an assist force is generated just as discussed above, the clutch member 45 is moved in the axial direction, and the clutch pawl 53 can be lowered.
["0061]" Here, since rotation is transmitted directly to the ring gear 43, without
going through the clutch member 45, there is a reduction in the operating force required during shifting in an upshift operation from the downshift side to the upshift side. Furt! crmore, since the rotational force of the clutch member 45 is assisted by being converted into displacement in the axial direction in a downshift operation from the upshift side to the downshift side, the rider can make a shift with a light force while still pedaling, even when upshifting.
[■ 0062] Embodiment 2
In the above Embodiment 1, a reduction in spring force was achieved during an upshift by installing the first coil spring 60 around the push rod, but the push rod 48a may instead be a rod-like member/ as shown in Figure 9. In this case, the first coil spring 60 is disposed in a compressed state between the clutch member 45 and the hub cone 31. The spring forces of the three coil springs 60 to 62 becomes increasingly smaller in the order of the second coil spring 61, the third coil spring 62, and the first
1 Translator's note: The first "rod" is phonetically rendered from the English in the original, whereas the second is written with the Chinese character for rod. The intended meaning here seems to be that the rod is by itself, with no spring attached.

coil spring 60. Here, if the energizing force of the second coil spring 61 is less than that of the third coil spring 62, then even if the shift key 49 is pressed in the retraction of the push rod 48a to the downshift side, the shift key 49 will not strike the clutch member 45, and no assist force will be obtained. Also, if the energizing force of the third coil spring 62 is less than that of the first coil spring 60, then when the push rod 48a1 is retracted to the downshift side and the second coil spring 61 presses on the shift key 49, the third coil spring 62 will bend, only the shift key 49 will move, and the shift key 49 and the clutch member ,45 will not be able to move away from each other, so the clutch member 45 cannot be positioned. The shift key 49 moves the clutch member 45 only on the downshift side, and the two move independently on the upshift side. In other words, a stop ring is not provided to the clutch member 45. The overall length of the third coil spring 62 is restricted to a specific length by a restricting member (not shown), and the spacing between the clutch member 45 and the shift key 49 is always kept the same even when the two move independently. The rest of the structure is the same as in Embodiment 1, and will not be described here.
[0063}-
Down shift-Upshift Actuation
In this Embodiment 2, in the state shown in Figure 9, in which the push rod 48a is not pushed in, the 45 is disposed at the downshift position on the right end, and the rotation from the driver 22 is transmitted to the hub shell 23 after being reduced in speed via the downshift power transmission path, just as in Embodiment 1. Specifically, the rotation inputted to the driver 22 is transmitted to the ring gear 43 via the second one-way clutch 51.
j; 0064] Meanwhile, when the winding lever of the shift control component 9 is
operated, the link member 71 of the bell crank 26 swings, and the push rod 48a is pushed in by one stage. As a result, the shift key 49 is pressed by the push rod 48a and moves to the left while rotating around the hub axle, and the clutch member 45, which is energized by the first coil spring 60, follows the shift key 49 and moves to the direct drive position. When the clutch member 45 is then disposed in the direct drive position, the clutch pawl 53 of the first one-way clutch 50, which had been put in a retracted attitude by the taper surface 45d, is returned to the erected attitude shown by the solid line in Figure 4 by the spring force of the torsion coil spring 55, and the
1 Translator's note: "48" in the original; probable typo.

rotation from the driver 22 is directly transmitted to the hub shell 23 through the direct drive power transmission path, just as in Embodiment I.
[0065} When winding lever is operated in the direct drive position and the push
rod 48a is pushed in further, the shift key 49 moves further to the left, and the clutch
member 45 follows this and also moves to the upshift position. When the clutch
member 45 is disposed in the upshift position, the serration outer teeth 45c of the clutch
member 45 and the serration inner teeth 41b of the gear frame 41 mesh with each
other. In this movement to the upshift position, when the serration outer teeth 45c and
the serration inner teeth 41b are disposed in the positions where they mesh, the clutch
member 45 moves directly to the upshift position to the left after the clutch member 45
strikes the gear frame 41. When, however, [these teeth] are disposed in positions
where they do not mesh, the clutch member 45 temporarily halts its movement to the
left at the point when the clutch member 45 strikes the gear frame 41. However, since
the clutch member 45 is pressed by the energizing force of the first coil spring 60,
when the clutch member 45 rotates and the two sets of teeth 45c and 41b reach their
meshing positions, the clutch member 45 moves and the two sets of teeth 45c and 41b
mesh. In this state, the rotation transmitted to the driver 22 is transmitted to the hub
shell 23 via the upshift transmission path just as in Embodiment 1.
E-QQ66] Since rotation is transmitted directly between the driver 22 and the ring
gear 43 during such a shift from the downshift side to the upshift side, it is best to move the clutch member 45, which has no force acting upon it. Accordingly, the spring force of the first coil spring 60 for pushing the clutch member 45 may be reduced, and shift operation can be performed with a light force.
Upshift-Downshift Assist Actuation
When the release lever of the shift control component 9 is operated at the upshift position, the shift key 49 is energized by the second coil spring 61, and the push rod 48a retracts by one stage to the left. The shift key 49 then presses on the clutch member 45 and attempts to move the clutch member 45 to the direct drive position. If the rider is pedaling, however, since drive force is being transmitted from the clutch member 45 to the gear frame 41, frictional force may cause the serration inner teeth 41b and the serration outer teeth 45b to remain meshed. In a case such as this, an assist force is generated and the clutch member 45 moved to the downshift side, just as in Embodiment 1 above.
[•096?} Meanwhile, even when a drive force larger than the set drive force is
applied, and the shift key 49 escapes in the axial direction without the clutch

member 45 moving, once the gear crank 18 reaches the vicinity of top dead center or
bottom dead center and the drive force decreases, the clutch member 45 will be pressed
and moved by the assist force produced by the shift key 49. Accordingly, again in this
Embodiment 2, a shift will not be performed when an extremely large drive force is
applied, which reduces shifting shock and helps prevent damage to the drive force
transmission parts, such as the serration teeth and the one-way clutches.
J-QG6&}- When the clutch member 45 moves to the right, the shift key 49 is
separated from the cam surface 47 by the third coil spring 62. Accordingly, there will be no noise generated by contact with the shift key 49 even if the clutch member 45 is rotated. When the clutch member 45 is then disposed in the direct drive position, rotation is transmitted via the direct drive transmission path.
When the release lever is operated in a state in which the clutch member 45 is
disposed in the direct drive position, the push rod 48a retracts further, and the shift
key 49 presses on the clutch member 45. At this point the taper surface 45d of the
clutch member 45 comes into contact with the clutch pawl 53 of the first one-way
clutch 50 and attempts to lower the clutch pawl 53 from an erected attitude to a
retracted attitude. However, because the clutch pawl 53 is transmitting power from the
ring gear 43 to the hub shell 23, it is not readily lowered to a retracted attitude by the
energizing force of the second coil spring 61 alone. Here again, when the shift key 49
strikes the cam surface 47 of the clutch member 45, an assist force can be generated
and the clutch member 45 moved in the axial direction, just as discussed above.
[-3669? The same merits as in Embodiment 1 are obtained here as well, and in
addition, the structure of the push rod 48 is simplified. In this case, however, since the energizing force is largest for the second coil spring 61, which is located in a relatively narrow space, if sufficient bending is ensured, then it is difficult to reduce the spring constant of the second coil spring 61, and there is a sharp increase in the spring force during bending. Consequently, a greater operating force is required during upshifting than in Embodiment 1.
r nmm
Embodiment 3
In Embodiment 2 above, the clutch member was disposed in the downshift position in a state in which it was not pressed by the push rod, but in this Embodiment 3, the clutch member 45 is disposed in the upshift position, as shown in Figure 10.

In this case, the second coil spring 61 is installed on the push rod 48. Also, the first coil spring 60 is disposed between the clutch member 45 and the hub cone 31. Also, the energizing forces of the three coil springs 60 to 62 becomes increasingly smaller in the order of the second coil spring 61, the third coil spring 62, and the first coil spring 60. The reason for setting the energizing forces of the springs in this way is the same as in Embodiment 2.
[%005l^ As shown in figure 10, the operation hole 21a is formed along the axis
from the left end (in Figure 10) of -the hub axle (the side on which the coaster brake is mounted) to the center. A bell crank (not shown) is mounted at the axial end on the left side of the hub axle 21. Because the push rod 48 strikes the triangular top of the shift key 49a, a notch surface 49b that strikes the push rod 48 is formed in the center of the shift key 49a. The first coil spring 60 is disposed in a compressed state between the clutch member 45 and the hub cone 31, just as in Embodiment 2, The rest of the structure is the same as in Embodiment 2, and will not be described here. [ 0072] Upshift-Downshift Assist Actuation
In this Embodiment 3, in the state shown in Figure 10, in which the push rod 48 is not pushed in, when the winding lever of the shift control component 9 is operated in the upshift position, the shift key 49a is pressed by the push rod 48, and the clutch member 45 is moved to the downshift side against the energizing force of the first coil spring 60. At this point, when no drive force is being transmitted, the shift key 49a presses the clutch member 45 via the third coil spring 62, and the clutch member 45 is moved to the direct drive position. When a drive force is being transmitted, the shift key 49a strikes the cam surface 47 while bending the third coil spring 62 or the second coil spring 61, and moves the clutch member 45 by means of the above-mentioned assist force. When the movement is from the direct drive position to the downshift position, if a drive force has been transmitted and it is difficult for the clutch pawl 53 to assume a retracted attitude, then the clutch member 45 is moved by the assist force, the clutch pawl 53 is put into a retracted attitude, and the clutch member 45 is moved to the downshift position.
E-QQ73-] Meanwhile, even when a drive force larger than the set drive force is
applied, and the shift key 49a escapes in the axial direction without the clutch member 45 moving, once the gear crank 18 reaches the vicinity of top dead center or bottom dead center and the drive force decreases, the clutch member 45 will be pressed and moved by the assist force produced by the shift key 49a. Accordingly, again in this Embodiment 3, a shift will not be performed when an extremely large drive force

is applied, which reduces shifting shock and helps prevent damage to the drive force transmission parts, such as the serration teeth and the one-way clutches.

Downshift-Upshift Actuation
When the release lever is operated in the downshift position, the clutch member 45 is pressed to the upshift side by the energizing force of the first coil spring 60, the push rod 48 moves, and the clutch member 45 moves to the direct drive position. When the clutch member 45 is then disposed in the direct drive position, the clutch pawl 53 of the first one-way clutch 50, which had been put in a retracted attitude by the taper surface 45d, is returned to the erected attitude shown by the solid line in Figure 4 by the spring force of the torsion coil spring 55, and the rotation from the driver 22 is directly transmitted to the hub shell 23 through the direct drive power transmission path, just as in Embodiments 1 and 2.
■{-0075}- When the release lever is operated in the direct drive position and the
clutch member 45 is pressed to the upshift side by the energizing force of the first coil spring 60, the push rod 48 moves and the clutch member 45 moves to the upshift position. When the clutch member 45 is disposed in the upshift position, the serration outer teeth 45c of the clutch member 45 and the serration inner teeth 41b of the gear frame 41 mesh with each other. In this movement to the upshift position, when the serration outer teeth 45c and the serration inner teeth 41b are disposed in the positions where they mesh, the clutch member 45 moves directly to the upshift position to the left after the clutch member 45 strikes the gear frame 41. When, however, [these teeth] are disposed in positions where they do not mesh, the clutch member 45 temporarily halts its movement to the left at the point when the clutch member 45 strikes the gear frame 41. However, since the clutch member 45 is pressed by the energizing force of the first coil spring 60, when the clutch member 45 rotates and the two sets of teeth 45c and 41b reach their meshing positions, the clutch member 45 moves and the two sets of teeth 45c and 41b mesh. In this state, the rotation transmitted to the driver 22 is transmitted to the hub shell 23 via the upshift transmission path just as in Embodiments 1 and 2.
[-69?6j Since rotation is transmitted directly between the driver 22 and the ring
gear 43 during such a shift from the downshift side to the upshift side, it is best to move the clutch member 45, which has no force acting upon it. Accordingly, the spring force of the first coil spring 60 for pushing the clutch member 45 may be reduced. Furthermore, since the energizing force is largest for the second coil spring 61, which has plenty of housing space, the spring force can be reduced overall, and a shift can be performed with a light force in a state in which a drive force is applied during riding.

Other Practical Examples
(a) The push rod in Embodiment 3 may consist of a rod-like member as in Embodiment 2. In this case, since the shift key is restricted in its movement to the axial end side by the push rod, a through-groove may be formed along the axis. In an embodiment such as this, a shift can be made at any time since an assist force will be generated even if a large force is applied. However, the push rod will be subjected to a large force here, as will the inner cable. The shifting shock will also be considerable, so the power transmission parts will have to be made stronger.
(b) In these embodiments, a pawl cage for preventing brake lock was provided since a coaster brake was installed, but no pawl cage is necessary if a coaster brake is not installed.
(c) The mechanism for transmitting rotation is not limited to a planet gear mechanism, and may instead be a planet roller mechanism.
Merits of the Invention
As discussed above, with the internal shifter hub pertaining to the present invention, the engagement of the clutch member with the clutch control component in the movement of the clutch member to the downshift side converts the rotational drive force of the clutch member into displacement in the axial direction and generates an assist force, so movement of the clutch member is facilitated and the clutch member can be moved with a light force even during riding. The clutch member can also be moved with a light force because no power is transmitted to the clutch member during movement to the upshift side. Accordingly, shifts can be performed in both directions with a light operating force even in a state in which drive force is applied during riding.

Accordingly, the present invention provides an internal hub transmission for a bicycle comprising: a hub axle having an axle axis and a dropout attachment location for retaining the transmission to a dropout of a bicycle frame; a driver rotatably supported relative to the hub axle; an output member rotatably supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; wherein the operation mechanism comprises an elongated control rod having at least a portion that is completely surrounded by the hub axle; wherein the control rod terminates at an end face before a free end of the hub axle; an actuating mechanism mounted on the hub axle inboard of a free end of the hub axle between the dropout attachment location and the driver for moving the operation mechanism in the direction of the axle axis; and wherein the actuating mechanism extends through a radially outer surface of the hub axle at a location outside the output member and presses against the end face of the control rod in the direction of the axle axis.
With reference to the accompanying drawings, in which
Figure 1 is a side view of a bicycle in which an embodiment of the present invention is employed;
Figure 2 is a vertical cross section of the structure of the internal shifter hub thereof;
Figure 3 is an enlarged detail view of the downshift position of this internal shifter hub;
Figure 4 is an oblique detail view of the operation mechanism;

Figure 5 is a schematic of the relation between the shift key and the cam surface;
Figure 6 is a cross section of the lateral portion of the push rod;
Figure 7 is a diagram corresponding to Figure 3 of the direct drive position of the internal shifter hub;
Figure 8 is a diagram corresponding to Figure 3 of the upshift position of the internal shifter hub;
Figure 9 is a diagram corresponding to Figure 3 of Embodiment 2; and
Figure 10 is a diagram corresponding to Figure 3 of Embodiment 3.
Key:
2 frame body
7 rear wheel
21 hub axle
21b through-groove 21c guide surface
22 driver
23 hub shell
24 planet gear mechanism
25 operation mechanism 32 hub cog

40 sun gear
41 gear frame
42 planet gear
43 ring gear
45 clutch member
47 cam surface
47c inclined surface
48 and 48a push rods
49 and 49a shift keys
50 to 52 first to third one-way clutches 60 to 62 first to third coil springs

65 operator
66 actuator

WE CLAIM:
1. An internal hub transmission for a bicycle comprising: a hub axle having an axle axis and a dropout attachment location for retaining the transmission to a dropout of a bicycle frame; a driver rotatably supported relative to the hub axle; an output member rotatably supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; wherein the operation mechanism comprises an elongated control rod having at least a portion that is completely surrounded by the hub axle; wherein the control rod terminates at an end face before a free end of the hub axle; an actuating mechanism mounted on the hub axle inboard of a free end of the hub axle between the dropout attachment location and the driver for moving the operation mechanism in the direction of the axle axis; and wherein the actuating mechanism extends through a radially outer surface of the hub axle at a location outside the output member and presses against the end face of the control rod in the direction of the axle axis.
2. The internal hub transmission as claimed in claim 1 further comprising a biasing member for biasing the operation mechanism in one direction of the axle axis, and wherein the actuating mechanism moves the operation mechanism in an opposite direction of the axle axis.
3. The internal hub transmission as claimed in claim 1 wherein the hub axle includes a groove for exposing the operation mechanism, and wherein the actuating mechanism extends into the groove.

4. The internal hub transmission as claimed in claim 3 wherein the groove is disposed
entirely inboard of the free end of the hub axle.
5. The internal hub transmission as claimed in claim 1 wherein the actuating mechanism is swingably mounted to the hub axle.
6. The internal hub transmission as claimed in claim 5 wherein the actuating mechanism comprises: a support member mounted to the hub axle; a link member swingably supported to the support member at an intermediate location of the link member.
7. The internal hub transmission as claimed in claim 6 wherein the link member includes: a first arm member extending from the intermediate portion for connecting to a control cable; and a second arm member extending from the intermediate portion for contacting the operation mechanism.

8. The internal hub transmission as claimed in claim 7 further comprising a link shaft pivotably supporting the intermediate portion of the link member to the support member.
9. The internal hub transmission as claimed in claim 6 wherein the support member includes a stop component for stopping an outer casing of a control cable.
10. The internal hub transmission as claimed in claim 6 wherein the support member
defines an opening for exposing the free end of the hub axle.
-32-

11. The internal hub transmission as claimed in claim 10 wherein the hub axle extends through the support member.
12. The internal hub transmission as claimed in claim I wherein the output member comprises a hub shell with a flange for supporting a plurality of spokes.
13. An internal hub transmission for a bicycle comprising: a hub axle having an axle axis for retaining the transmission to a bicycle frame; a driver rotatably supported relative to the hub axle; an output member rotatable supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; wherein the operation mechanism comprises an elongated control rod having at least a portion that is completely surrounded by the hub axle; wherein the control rod terminates at an end face before a free end of the hub axle; an actuating mechanism swingably mounted on the hub axle inboard of a free end of the hub axle for moving the operation mechanism in the direction of the axle axis; wherein the actuating mechanism extends through a radially outer surface of the hub axle at a location outside the output member and presses against the end face of the control rod in the direction of the axle axis; wherein the actuating mechanism comprises: a support member mounted to the hub axle; and a link member swingably supported to the support member at an intermediate location of the link member; wherein the hub axle comprises a groove for exposing the operation mechanism, and wherein the link member extends into the groove.

14. The internal hub transmission as claimed in claim 13 wherein the groove is disposed entirely inboard of the free end of the hub axle.
15. The internal hub transmission as claimed in claim 13 wherein the link member includes: a first arm member extending from the intermediate portion for connecting to a control cable; and a second arm member extending from the intermediate portion for contacting the operation mechanism.
16. The internal hub transmission as claimed in claim 15 further comprising a link shaft pivotably supporting the intermediate portion of the link member to the support member.
17. The internal hub transmission as claimed in claim 16 wherein the support member defines an opening for exposing the free end of the hub axle.
18. The interna] hub transmission as claimed in claim 17 wherein the hub axle extends through the support member.
19. The internal hub transmission as claimed in claim 18 further comprising a biasing member for biasing the operation mechanism in one direction of the axle axis, and wherein the second arm member moves the operation mechanism in an opposite direction of the axle axis.
20. The internal hub transmission as claimed in claim 19 further comprising a shift key that slides within a second groove formed in the hub axle in response to movement of the control rod in the direction of the axle axis.
-id.

21. An internal hub transmission assembly for a bicycle comprising: a rear dropout of a bicycle frame; a hub axle retained to the rear dropout and having an axle axis; a driver rotatably supported relative to the hub axle; an output member rotatably supported relative to the hub axle; a power transmission mechanism disposed between the driver and the output member for communicating rotational force of the driver to the output member through a plurality of transmission paths; an operation mechanism disposed in the hub axle for movement in the direction of the axle axis to select among the plurality of transmission paths; and an actuating mechanism mounted on the hub axle inboard of a free end of the hub axle between the rear dropout and the driver, wherein the actuating mechanism moves in the direction of the axle axis for moving the operation mechanism in the direction of the axle axis.

Documents:

1005-mas-1998 abstract duplicate.pdf

1005-mas-1998 abstract.pdf

1005-mas-1998 claims duplicate.pdf

1005-mas-1998 claims.pdf

1005-mas-1998 correspondence-others.pdf

1005-mas-1998 correspondence-po.pdf

1005-mas-1998 description (complete) duplicate.pdf

1005-mas-1998 description (complete).pdf

1005-mas-1998 drawings.pdf

1005-mas-1998 form-19.pdf

1005-mas-1998 form-2.pdf

1005-mas-1998 form-26.pdf

1005-mas-1998 form-4.pdf

1005-mas-1998 form-6.pdf

1005-mas-1998 others.pdf

1005-mas-1998 petition.pdf

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Patent Number

196306

Indian Patent Application Number

1005/MAS/1998

PG Journal Number

30/2009

Publication Date

24-Jul-2009

Grant Date

Date of Filing

08-May-1998

Name of Patentee

SHIMANO INC,

Applicant Address

77 OIMATSU-CYO 3-CYO, SAKAI-SHI, OSAKA-590-77,

Inventors:

#	Inventor's Name	Inventor's Address
1	WATARU UCHIYAMA	601-4-1-103, OAZAYASHIDA, SHIMONOSEKI-SHI, YAMAGUCHI,

PCT International Classification Number

B62M11/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	H9-117996	1997-05-08	Japan