Title of Invention	MOTORCYCLE CLUTCH DEVICE
Abstract	The device includes a clutch housing 1, an output rotary member 2, a clutch part 3 having a plurality of clutch plates, a pressure plate 4, a diaphragm spring 5 having a disc-like pressing part 5a and a lever part 5b, and an elastic member 7 to generate drag torque. The elastic member 7 that generates drag torque is provided between the pressure plate 4 and the pressing part 5a of the diaphragm spring 5 and presses the pressure plate 4 with a load smaller than the pressing load of the diaphragm spring 5 when the power is interrupted in the clutch part 3.

Title of Invention

MOTORCYCLE CLUTCH DEVICE

Abstract

The device includes a clutch housing 1, an output rotary member 2, a clutch part 3 having a plurality of clutch plates, a pressure plate 4, a diaphragm spring 5 having a disc-like pressing part 5a and a lever part 5b, and an elastic member 7 to generate drag torque. The elastic member 7 that generates drag torque is provided between the pressure plate 4 and the pressing part 5a of the diaphragm spring 5 and presses the pressure plate 4 with a load smaller than the pressing load of the diaphragm spring 5 when the power is interrupted in the clutch part 3.

Full Text	[Title of Document] Specification [Title of the invention] Motorcycle Clutch Device [Technical field] [0001] The present invention is related to a clutch device, particularly to a motorcycle clutch device for transmitting power from an input member to an ou^ut member and interrupting the power transmission by the operation of a release mechanism. [Background art] [0002] Generally, motorcycles such as two-wheeled motor vehicles and ATVs employ a multi-plate clutch device for transmitting and interrupting the power from the engine to the transmission. The multi-plate clutch device includes a clutch housing connected to the engine crankshaft arrangement, an output rotary member connected to the transmission arrangemait, a clutch part for transmitting and interrupting the power therebetween, and a pressure plate for pressing the clutch part The clutch part includes a first plate and a second clutch plate located alternately, with the first clutch plate being engaged with the clutch housing and the second clutch plate being engaged with the output rotary member. [0003] By pressing the clutch plates against one another by way of a pressing member such as a spring via the pressure plate, the drive of the crankshaft is transmitted to the transmission. When the clutch is released to interrupt the power transmission, the operator grips the clutch lever to operate the release mechanism. The release mechanism releases the pressure of the pressing member to the clutch plates so that tiie power transmission between the first and second clutch plate is interrupted. Patent Document 1 Unexamined Patent Publication 2003-222159 [Disclosure of Invention] [Problems to be solved by the invention] [0004] In a vehicle such as a two-wheeled motor vehicle and so on employing the above-mentioned clutch device, the transmission generally employs a dog clutch system, in which it is difficult to shift gear from neutral to first while parking because the dog clutch system transmission does not include a synchronization mechanism. More specifically, when the vehicle parks with the lever in the neutral position, a train of output gears in the transmission does not rotate because the gears are coupled to the tires, while a train of input gears does not rotate because the clutch is disengaged in a power interrupting state so that in many cases the input gears and the output gears do not engage with each other when the driver tries to shift gear from neutral to first [0005] Therefore, in conventional devices of this type, various components are installed between a plurality of plates in the clutch part in order to generate drag torque in neutral and rotate the input gears of the transmission. [0006] However, a conventional device of this type has a complicated structure so that it is troublesome to assemble it and the cost is high. [0007] It is an object of the present invention to generate drag torque with a simple structure when the clutch is disengaged in order to make it easy to shift gear first neutral to first or others while parking. [Means for solving problems] [0008] According to a motorcycle clutch device of claim 1, the device transmits power from an input member to an output member and intermpts the power transmission by the operation of a release mechanism. The device includes a clutch housing, a rotary member, a clutch part, a pressure plate, a release member, a pressing member, and a pushing member to generate drag torque. The clutch housing is coupled to one of the input member and output member. The rotary member is provided within the clutch housing and coupled to the other of the input member and the output member. The clutch part includes at least one plate member to transmit and to interrupt power between the clutch housing and the rotary member. The pressure plate presses the plate member of the clutch part The pressing member includes a disc-like pressing part to press the pressure plate. The release member releases the pressing load of the pressing member to the pressure plate. The pushing member to generate drag torque is provided between the pressure plate and the pressing part of the pressing member. The pushing member pushes the pressure plate with a load less than the pressing load of the pressing member when the power is ratermpted in the clutch part. [0009] In this clutch device, the pressure force by the pressing member is applied to the clxitch part via the pressure plate so that the clutch part is engaged, i.e., in a power transmitting state. In this state, the power from the input member is input to the clutch housing, for example, and then transmitted to the rotary member via the clutch part, and finally output to the output member. Alternatively, in a case in which power from the input member is input to the rotary member, the power is transmitted to the clutch housing via the clutch part and output to the output member. When the clutch is released, i.e., in a power interrupting state, the release mechanism operates the pressing member so that the pressure force of the pressing part to the pressure plate is released. [0010] In this clutch device, the pushing member to generate drag torque pushes the pressure plate with a relatively small load when the clutch is disengaged. Consequently, the clutch part generates drag torque with this load so that the input gears rotate at a low speed in the transmission. As a result, it is easy to shift gears from neutral into other positions while parking. Furthermore, the structure is simple and the assembly is easy because the pushing member to generate drag torque is located between the disc-like pressing part of the pressing member and the pressure plate. [0011] According to a motorcycle clutch device of claim 2 depending on claim 1, the pressing member is a diaphragm spring having the pressing part at the radially outer portion, and a lever part at the radially inner portion to release the pressure force of the pressing part while amplifying power from the release mechanism with a lever ratio. [0012] In this device, the control force of the release mechanism is amplified by the lever ratio of the lever part and is applied to the pressing part so that it is possible to release the clutch with less control force by the lever ratio compared to the conventional clutch device. In addition, the structure of the pressing member is simplified. [0013] According to a motorcycle clutch device of claim 3 depending on claim 2, the diaphragm spring is constructed such that the pressing part has a radially outer portion pressing the pressure plate, and a radially inner portion supported by the rotary member. A radially inner portion of the lever part is adapted to be moved toward the pressure plate by the release mechanism. [0014] In this device, the release mechanism operates the radially inner portion of the lever part of diaphragm spring to move the radially outer portion of the pressing part away from the pressure plate. thereby releasing the pressure force of the pressing part to the pressure plate. [0015] Since the radially inner portion of the pressing part of the diaphragm spring is supported by the radially outer portion of the rotary member, the structure that supports the diaphragm spring is simplified and the axial lengh of the device is reduced In a typical clutch device for a motor vehicle of the type wherein the radially inner end of the diaphragm spring is driven toward the engine to release the clutch engagement, the radially inner portion of the pressing part of the diaphragm spring is supported by the clutch cover. In this clutch cover support structure, the support portion is a portion that extends radially inward from the radially outer portion of the clutch cover to surround circumferentially the outside of the diaphragm spring. In this structure, it is necessary to ensure a relatively large space in the axial direction to support the diaphragm spring. In the present invention, in contrast, as mentioned before, it is possible to support the diaphragm spring within a relatively small space in the axial direction because the radially outer portion of the rotary member supports the diaphragm spring. [0016] According to a motorcycle clutch device of claim 4 depending on claim 3, the pressure plate is formed to have a press protrusion protruding in the axial direction at a portion to be pressed by the pressing part The pushing member that generates drag torque has a radially outer portion supported by a radially inner portion of the press protrusion. Therefore, the pushing member for generating drag torque is held in a position with a simple structure since the pushing member that generates drag torque is supported by the press protrusion of the pressure plate. [0017] According to a motorcycle clutch device of claim 5 depending on claim 2, the diaphragm spring is constructed such that the pressing part has a radially outer portion supported by the rotary member and a radially inner portion pressing the pressure plate. A radially inner portion of the lever part is adated to be moved away from the pressure plate by the release mechanism. [0018] In the device, the release mechanism operates the radially inner portion of the lever part of diaphragm spring to move the radially inner portion of the pressing part away from the pressure plate, thereby releasing the pressure force of the pressing part to the pressure plate. [0019] According to a motorcycle clutch device of claim 6 depending on any of claims 1 to 5, the rotary member has a friction part facing the pressure plate at the radially outer portion. The clutch part includes a first clutch plate engaged with the clutch housing and a second clutch plate engaged with the rotary member. The first and second clutch plates are adapted to be clamped between the fiiction part of the rotary member and the pressure plate. [0020] In the device, the first and second clutch plates constituting the clutch part are clamped between the friction part of the rotary member and the pressure plate, and the power is transmitted through a driveline of the clutch housing, the first clutch plate, the second clutch plate, and the rotary member in this order. [0021] According to a motorcycle clutch device of claim 7 depending on any of claims 1 to 6, the pushing member that generates drag torque is an elastic member which is elastically deformable in the compression direction. [0022] According to a motorcycle clutch device of claim 8 depending on claim 7, the pushing member that generates drag torque is a compression coil spring. [Brief description of drawings] [0023] Fig. 1 is a cross sectional view of a motorcycle clutch device of the first embodiment of the present invention. Fig. 2 is a front view of a motorcycle clutch device of the first embodiment of the present invention. Fig. 3 is a view corresponding to Fig. 1 of the second embodiment of the present invention. Fig. 4 is a view of showing a modification of the first embodiment of present invention [Explanations of letters or numerals] [0024] 1.101 clutch housing 2.101 output rotary member 3.101 clutch part 4.101 pressure plate 4c press protrusion 5.101 diaphragm spring 5a, 105a pressing part 5b, 105b lever part 6.101 release member 7.101 urging member for generating drag torque 17,117 input shaft 19,119 support plate 25,26,125,126 clutch plate [Best mode for carrying out the invention] [0025] [First embodiment] A motorcycle clutch device shown in Figs. 1 and 2 transmits power from the crankshaft of the engine to the transmission and interrupts power by the operation of the release mechanism. The clutch device employs a push-type release mechanism wherein the clutch is disengaged by pushing the release bearing inward in the axial direction, and includes a clutch housing 1, an output rotary member 2, a clutch part 3 to transmit and to interrupt the power between the clutch housing 1 and the output rotary member 2, a pressure plate 4, a diaphragm spring 5, a release member 6, and an elastic member 7 to generate drag torque. [0026] The clutch housing 1 has a disc part 10 and a tubular part 11 extending axially outward (rightward in Fig. 1) from a radially outer end of the disc part 10. An input gear 13 is mounted on the disc part 10 via a plurality of annular mbber members 12. The input gear 13 is engaged with a driving gear (not shown) that is fixed to the crankshaft of the engine. It should be understood that the mbber members 12 are provided to absorb vibrations from the engine, and coil springs can replace them, for example. The tubular part 11 is formed with a plurality of concave portions dented outward in the radial direction on the inner circumference. The tubular part 11 is formed with circumferentially spaced cutouts extending in the axial direction. The cutouts serve to allow an inside lubricating oil to escape radially outward. [0027] The output rotary member 2 is located within the clutch housing 1. The output rotary member 2 has a disc shape and is formed with a spline 15 at its radially outer end and a spline bore 16 at its radially inner end The spline bore 16 at the radially inner end is engaged with the input shaft 17 of the transmissioa The radially outer portion of the output rotary member 2 is formed with a disc-like friction part 18 as a flange extending radially outward from the axially inner end In addition, the output rotary member 2 is formed with a plurality of support protrusions 2a spaced circumferentially at the radially outer end of an axially outer surface thereof Moreover, the output rotary member 2 is formed with a plurality of bosses 2b on the axially outer surface and radially inward of the support protrusions 2a, the bosses 2b extending in the axial direction and spaced in the circumferential direction. The boss 2b is formed with a faucet joint protrusion 2c at the radially inner end, the protrusion 2c further protruding in the axial directioa [0028] A support plate 19 is fixed to the bosses 2b of the output rotary member 2 by rivets 20 to support the di^hragm spring 5 on the output rotary member 2. The support plate 19 is an annular member having a radially inner end supported by the faucet joint protrusions 2c of the output rotary member 2. The radially outer portion of the support plate 19 is formed with an annular support protrusion 19a protruding inward in the axial direction, and the radially inner end is formed with, as clear from Fig. 2, a plurality of engagement slots 19b circumferentially spaced. A thrust plate 21 is disposed between a radially inner portion of the input gear 13 and a radially inner portion of the output rotary member 2. [0029] The clutch part 3 includes two first clutch plates 25 and one second clutch plate 26 having an annular shape and alternately stacked in the axial direction. The radially outer end of the first clutch plate 25 is formed with a plurality of engagement protrusions extending outward and engaged with the concave portions on the inner circumference of the tubular part 11 of clutch housing 1. The first clutch plate 25 has opposite surfaces to which friction facings are attached. The spline of the radially inner portion of the second clutch plate 26 is engaged with the spline 15 formed at the radially outer end of the output rotary member 2. [0030] The pressure plate 4 has an annular shape and is located on the outside of first clutch plate 25 farthest outward in the axial direction. The pressure plate 4 is formed with a spline bore 4a at the radially inner end, with the spline bore 4a being engaged with the outer spline 15 of the output rotary member 2. The pressure plate 4 is formed with an annular protrusion 4b axially extending at a radially outer portion of the axially outer surface, and a press protrusion 4c extending in the axial direction located radially inward of the annular protrusion 4b. The annular protrusion 4b extends outward in the axial direction past the press protrusion 4c. The diaphragm spring 5 is an annular plate member having a pressing part 5a as a disc spring at its radially outer portion and a lever part 5b at its radially inner portion to release the pressure of the pressing part 5a The lever part 5b is formed with a contact part 5c projecting outward in the axial direction at the radially inner end. The diaphragm spring 5 is located such that the radially outer portion of the diaphragm spring 5 is supported by the inner circumference of the annular protrusion 4b of the pressure plate 4. In the pressing part 5a of the diaphragm spring 5, the radially outer portion is supported by the press protrusion 4c of the pressure plate 4 and the radially inner portion is clamped and supported between the support protrusions 2a of the output rotary member 2 and the support protrusion 19a of the support plate 19. The diaphragm spring 5, as shown in Fig. 1, urges the pressure plate 4 inward in the axial direction with a predetemined pressure force by way of an urging force of the disc spring. Accordingly, the first and second clutch plates 25 and 26 of the clutch part 3 are clamped between the friction part 18 of the output rotaiy member 2 and the pressure plate 4, , [0032] The lever part 5b of the di^hragm spring 5 is made of a plurality of levers arranged radially. Formed between two circumferentially adjacent levers is a wide slit, and the boss 2b of the output rotary member 2 passes though the slit outward in the axial direction. As mentioned before, since the boss 2b of the output rotary member 2 passes through the slit of lever part 5b of the diaphragm spring 5, relative rotation is prohibited between the diaphragm spring 5 and the support plate 19 as well as the output rotary member 2. [0033] The release member 6 is an annular plate member and has a radially inner portion holding a release bearing 30, More specifically, the release member 6 is formed with a bearing support part 6a at the axially inner end on the inner circumference, with which an axially inner shoulder portion of an outer race of the release bearing 30 is engaged. Furthemore, an axially inner surface of the release member 6 is configured to press the contact part 5c of the diaphragm spring 5. The release member 6 is formed with a plurality of claws 6b extending radially outward at the radially outer portion, as shown in Fig. 2. The claws 6b are located equidistantly in the circumferential direction and are fitted into the engagement slots 19b of the support plate 19. [0034] Since the claws 6b of the release member 6 are engaged with the engagement slots 19b, the release member 6 is centered and relative rotation of the release member 6 relative to the diaphragm spring 5, the support plate 19 and the output rotary member 2 is prohibited. [0035] The elastic member 7 that generates drag torque is located between the pressure plate 4 and the pressing part 5a of the diaphragm spring 5. The elastic member 7 pushes the pressure plate 4 toward the clutch part 3 with a load less than the pressing load of the diaphragm spring 5 when the clutch is disengaged. The elastic member 7 is a plurality of resin members elastically deformable in the compression directioa A radially outer portion of each elastic member 7 is supported by the radially inner portion of the press protrusion 4c of the pressure plate 4 so that the elastic member 7 is positioned in the radial direction. It is noted that the pressure force of the elastic member 7 is set to generate drag torque to such an extent that the engme does not stop when the clutch is disengaged to shift gears from neutral. [0036] Next, the operation will be described. [0037] As mentioned before, the pressing part 5a of the diaphragm spring 5, as shown in Fig, 1, urges the pressure plate 4 inward in the axial direction with a predetermined pressure force by way of an urging force of the disc spring. Accordingly, the first and second clutch plates 25 and 26 of the clutch part 3 are clamped between the fiiction part 18 of the output rotary member 2 and the pressure plate 4. In this state, the clutch is engaged so that the drive input from the crankshaft via the input gear 13 and the mbber members 12 is transmitted to the first clutch plates 25 via the clutch housing 1, then from the second clutch plate 26 to the output rotary member 2, and finally to the input shaft 17 of the transmission [0038] When the driver grips the clutch lever, the control force is transmitted to the release bearing 30 via clutch wires to move the release bearing 30 inward in the axial direction. The travel of the release bearing 30 is transmitted to lever part 5b of the diaphragm spring 5 via the release member 6 to move the radially inner portion of the lever part 5b inward in the axial direction. Then, the radially outer portion of the pressing part 5a pivots about the radially intermediate portion of diaphragm spring 5, that is, a portion supported by the support protrusions 2a and 19a, outward in the axial direction, and the radially outer portion of the pressing part 5a moves away from the press protrusion 4c of the pressure plate 4. Consequently, the pressure force toward the pressure plate 4 is released, and the clutch part 3 is disengaged. [0039] In this clutch disengagement state, the pressure force of the diaphragm spring 5 to the clutch part 3 is released. However, since the elastic member 7 that generates drag torque is provided between the diaphragm spring 5 and the pressure plate 4, a pressing load suflBcientiy smaller than the pressing load of the diaphragm spring 5 is applied to the pressure plate 4. Accordingly, the clutch part 3 generates drag torque in response to the pressing load of the elastic member 7 to generate drag torque. Consequently, the drag torque is transmitted to the input shaft 17 of the transmission so that the input gear is rotated at low speed. As a result, when shifting gears from neutral to first, for example, the input gears and the output gears in the transmission smoothly go into engagement, thereby making it easy to shift gears. [0040] In the aforementioned operation, when the clutch is released, the control force is lessened by the operation of the lever part 5b. More specifically, for example, if pressure force from the pressing part 5a of the diaphragm spring 5 is expressed as P, the release load R to be applied to the lever part 5b in order to release the pressure force P is expressed as follows: R=P(L1/U) LI: a distance from a fulcrum portion in the radially inner portion of the pressing part to a pressing point in the radially outer portion of the pressing part; L2: a distance from the fulcrum portion in the radially inner portion of the pressing part to a portion in the lever part contacting the release member. As a result, the release load is lessened by the lever ratio (L1/L2). Consequently, if the release load is set to one equivalent to that of the conventional device, the pressure load of the pressing part 5a can be increased by the lever ratio, while if the transmission capacity of the clutch is set to one equivalent to that of the conventional device, the number of the clutch plates can be decreased and as a result the clutch device is made more compact. [0041] By the engagement between the claws 6b of the release member 6 and the engagement slots 19b of the support plate 19 in this device, the release member 6 is centered, which means that the release member 6 is centered with a simple structure and the release operation is smoothly carried out In addition, according to a similar reason, since the release member 6 and the diaphragm spring 5 are prohibited from rotating relative to each other, wear at the contact portions between the di^hragm spring 5 and the release member 6 is restrained. Furthermore, since the support plate 19 is fixed to the output rotary member 2 though the slits of the lever part 5b of the diaphragm spring 5, relative rotation is prohibited between the diaphragm spring 5 and the output rotary member 2 as well as the support plate 19. As a result, wear at contact portions of the support protrusions 2a and 19a and the diaphragm spring 5 is restrained. [0042] Furthermore, since the radially outer portion of the diaphragm spring 5 is supported by the projection 4b of the pressure plate 4, the diaphragm spring 5 is precisely centered by a simple structure, thereby stabilizing spring characteristics. [0043] In addition, in this embodiment, although it is necessary to support the diaphragm spring 5 at fte radially intemiediate portion, i.e., the radially inner portion of the pressing part 5a, the radially outer portion of the output rotary member 2 supports the diaphragm spring 5 from radially inside so that it is possible to support the diaphragm spring 5 in a simplified manner and in a smaller space compared to a clutch cover support structure of a conventional vehicle clutch device. [Second embodiment ] Fig. 3 shows the second embodiment of the present invention. In the second embodiment, unlike the first embodiment, the clutch device employs a pull-type release mechanism wherein the clutch is disengaged by pulling the release bearing outward in the axial direction. The motorcycle clutch device has a basic structure similar to the first embodiment and includes a clutch housing 101, an output rotary member 102, a clutch part 103 to transmit and to interrupt the power between the clutch housing 101 and the output rotary member 102, a pressure plate 104, a diaphragm spring 105, a release member 106, and an elastic member 107 to generate drag torque. Explanation about the clutch housing 101 and the clutch part 103 will be omitted because the structures are almost the same, and other structures will be described. [0045] The output rotary member 102 has a disc shape and is formed with a spline 115 at its radially outer end and a spline bore 116 at its radially inner end. The spline bore 116 at the radially inner end is engaged with the input shaft 117 of the transmission. The output rotary member 102 is locked to the input shaft 117 by a nut 117a that is tightened to the tip of the input shaft 117 such that the output rotary member 102 cannot move in the axial direction. The radially outer portion of the output rotary member 102 is formed with a disc-like friction part 118 as a flange extending radially outward from the axially inner end. Furthermore, the output rotary member 102 is formed with a plurality of bosses 102a at the radially outer portion of the axially outer surface, the bosses 102a being located equidistantly in the circumferential direction and extending in the axial direction At the radially inner end of the boss 102a, a faucet joint protrusion 102b further extending in the axial direction is formed. [0046] A support plate 119 is fixed to axial surfaces of the bosses 102a of the output rotary member 102 by bolts 120 to support the dighragm spring 105 on the output rotary member 102. The support plate 119 is an annular member having a radially inner end supported by the faucet joint protrusions 102b of the output rotary member 102. The radially outer end of the support plate 119 is formed with an annular support protrusion 119a protruding inward in the axial directioa A thrust plate 121 is provided between a radially inner portion of the input gear 113 and a radially inner portion of the output rotary member 102. [0047] The pressure plate 104 has an annular shape and is located on the outside of the first clutch plate 125 farthest outward in the axial direction. The pressure plate 104 is formed with a plurality of teeth 104a projecting inward in the axial direction at the radially inner end, being engaged with the outer spline 115 of the output rotary member 102. The pressure plate 104 is formed with an annular projection 104b axially extending at a radially outer portion of the axially outer surface, and the annular projection 104b is formed with a plurality of slits 104c. The pressure plate 104 is formed with a press protrusion 104d extending in the axial direction located at the radially inner end of the axially outer surface. The annular projection 104b extends outward in the axial direction over the press protrusion 104d. [0048] The diaphragm spring 105 is an annular plate member having a pressing part 105a as a disc spring at its radially outer portion and a lever part 105b at its radially inner portion to release the pressure of the pressing part 105a. In addition, the pressing part 105a is formed with a plurality of engagement claws 105c at the radially outer end, and the lever part 105b is formed with a plurality of engagement inner teeth 105d at the radially inner end, with the engagement claws 105c being engaged with the slits 104c of the projection 104b of the pressure plate 104. In the pressing part 105a of the di^hragm spring 105, the radially outer portion is supported by the support protrusion 119a of the support plate 119 and the radially inner portion is in contact with the press protrusion 104d of the pressure plate 104. [0049] The diaphragm spring 105, as shown in Fig. 3, urges the pressure plate 104 inward in the axial direction with a predetermined pressure force by way of an urging force of the disc spring. Accordingly, the first and second clutch plates 125 and 126 of the clutch part 103 are clamped between the friction part 118 of the output rotary member 102 and the pressure plate 104. [0050] The lever part 105b of the diaphragm spring 105 is made of a plurality of levers arranged radially. Formed between circumferentially adjacent levers are wider slits, and bosses 102a of the output rotary member 102 pass though the slits outward in the axial directioa [0051] The release member 106 is an annular member and has a radially inner portion holding a release bearing 130. More specifically, an outer race of the release bearing 130 is fitted into the inner circumference of the release member 106 and a stopper ring 131 is attached to the inner surface of the release bearing 130 outward of the outer race in the axial direction. An axially outer shoulder of the outer race is in contact with the stopper ring 131. The release member 106 is formed with engagement outer teeth 106a on the outer circumference, with which the inner teeth 105d formed at the radially inner end of the dighragm spring 105 are engaged. Furthermore, the release member 106 is formed with a contact part 106b projecting outward at the axially inner end on the outer circumference, and a stopper ring 132 is disposed with a distance outward of the contact part 106b in the axial direction, with the radially inner end of the lever part 105b of the diaphragm spring 105 being sandwiched between the contact part 106b and the stopper ring 132. The release bearing 130 is adapted to be moved outward in the axial direction by the operation of the clutch lever of the motorcycle not shown. [0052] The elastic member 107 that generates drag torque is located between the pressure plate 104 and the pressing part 105a of the diaphragm spring 105. The elastic member 107 pushes the pressure plate 104 toward the clutch part 103 with a load less than the pressing load of the diaphragm spring 105 when the clutch is disengaged. The elastic member 107 is a plurality of resin members elastically deformable in the compression direction, and each of the elastic members 107 is supported by the concave portions formed radially outward of the press protrusion 104d of the pressure plate 104 so that the elastic member 107 is positioned in the radial direction. [0053] Next, the operation will be described. [0054] As mentioned before, the pressing part 105a of the diaphragm spring 105, as shown in Fig. 3, urges the pressure plate 104 inward in the axial direction with a predetermined pressure force by way of an urging force of the disc spring. Accordingly, the first and second clutch plates 125 and 126 of the clutch part 103 are clamped between the fiiction part 118 of the output rotary member 102 and the pressure plate 104. In this state, the clutch is engaged so that the drive input from the crankshaft via the input gear 113 and the mbber members 112 is transmitted to the first clutch plates 125 via the clutch housing 101, then from the second clutch plate 126 to the output rotary member 102, and finally to the input shaft 117 of the transmission. [0055] When the driver grips the clutch lever, the control force is transmitted to the release bearing 130 via clutch wires to move the release bearing 130 outward in the axial direction. The travel of the release bearing 130 is transmitted to lever part 105b of the dighragm spring 105 via the release member 106 to move the radially inner portion of the lever part 105b outward in the axial direction. Then, the radially inner portion of the pressing part 105a pivots about the radially outer portion of diaphragm spring 105, i.e,, a portion supported by the support protrusion 119a of the support plate 119, outward in the axial direction, and the pressing part 105a moves away from the press protrusion 104d of the pressure plate 104. Consequently, the pressure force toward the pressure plate 104 is released, and the clutch part 103 is disengaged. [0056] Although the pressure force of the dighragm spring 105 to the clutch part 103 is released in the clutch release state mentioned before, since the elastic member 107 that generates drag torque is provided between the diaphragm spring 105 and the pressure plate 104, a pressing load sufficiently smaller than the pressing load of the diaphragm spring 105 is applied to the pressure plate 104. Accordingly, the clutch part 103 generates drag torque in response to the pressing load of the elastic member 107 that generates drag torque. Consequently, the drag torque allows the input gears to rotate at low speed As a result, when shifting gear from neutral to first, for example, the input gears and the output gears in the transmission smoothly go into engagement, thereby making it easy to shift gear. [0057] Similarly to the first embodiment, v^en the clutch is released, the control force is lessened by the operation of the lever part 105b. More specifically, for example, if pressure force from the diaphragm spring 105 is expressed as P, the release load R to be applied to the lever part 105b in order to release the pressure force P is expressed as follows: R=P(L3/L4) L3: a distance from a fulcrum portion in the radially outer portion of the pressing part to a pressing point in the radially inner portion of the pressing part; L4: a distance from a fialcrum portion in the radially outer portion of the pressing part to a portion in the lever part contacting the release member. In other words, the release load is lessened by the lever ratio (L3/L4), [0058] Since the inner teeth 105d at the tip of the lever part 105b and the outer teeth 106a of the release member 106 are engaged in this device in order to prohibit the relative rotation between the dighragm spring 105 and the release member 106, wear at the contact portions between the diaphragm spring 105 and the release member 106 is restrained. Furthermore, since the radially outer portion of the dighragm spring 105 is supported by the projection 104b of the pressure plate 104, the dighragm spring 105 is precisely centered with a simple structure, thereby stabilizing spring characteristics. Furthermore, since the claws 105c at the radially outer end of the diaphragm spring 105 are engaged with the slits 104c of the pressure plate 104, relative rotation between them is prohibited, thereby restraining wear at their contact portions. [0059] [Other embodiments] (a) Although the resin that is elastically deformable in the compression direction is used as an elastic member to generate drag torque in the above embodiment, a compression coil spring may be used. The structure of this embodiment is shown in Fig. 4. In the embodiment shown in Fig. 4, in place of the resin urging member 7 in the first embodiment, compression coil springs T are used and the pressure plate 4 is formed with protrusions 4d to support the coil springs T. Other components are the same as those of the first embodiment. [0060] (b) Although in the aforementioned embodiment the drive is input from the input gear and is output to the output rotary member, the present invention can be applied to another case wherein the driveline is reversed as well. In a motorcycle clutch device according to the present invention, drag torque is generated with a simple structure when the clutch is disengaged so that it is easy to shift gears from neutral to first while parking. [Title of Document] Claims 1. A motorcycle clutch device for transmitting power from an input member to an output member and interrupting power transmission by an operation of a release mechanism, comprising: a clutch housing being coupled to one of the input member and the output member; a rotary member being provided within the clutch housing and coupled to the other of the input member and the output member, a clutch part including at least one plate member to transmit and to interrupt power between the clutch housing and the rotary member, a pressure plate being configured to press the plate member of the clutch part; a pressing member including a disc-like pressing part to press the pressure plate; a release member being configured to release the pressing load of the pressing member to the pressure plate; and a pushing member being configured to generate drag torque provided between the pressure plate and the pressing part of the pressing member, the pushing member pushing the pressure plate with a load less than the pressing load of the pressing member when the power is interrupted in the clutch part 2. A motorcycle clutch device according to claim 1, wherein the pressing member is a diaphragm spring having the pressing part at the radially outer portion, and a lever part at the radially inner portion to release the pressure force of the pressing part while amplifying power from the release mechanism with a lever ratio. 3. A motorcycle clutch device according to claim 2, wherein the diaphragm spring is constructed such that the pressing part has a radially outer portion pressing the pressure plate and a radially inner portion supported by the rotary member, and a radially inner portion of the lever part is ad^ted to be moved tow^ard tiie pressure plate by the release mechanism. 4. A motorcycle clutch device according to claim 3, wherein the pressure plate is formed with a press protrusion protruding in the axial direction at a portion to be pressed by the pressing part, and the pushing member that generates drag torque has a radially outer portion supported by a radially inner portion of the press protrusion. 5. A motorcycle clutch device according to claim 2, wherein the diaphragm spring is constructed such that the pressing part has a radially outer portion supported by the rotary member and a radially inner portion pressing the pressure plate, and a radially inner portion of the lever part is adapted to be moved away from the pressure plate by the release mechanism. 6. A motorcycle clutch device according to any of claims 1 to 5, wherein the rotary member has a friction part facing the pressure plate at the radially outer portion, and the clutch part includes a first clutch plate engaged with the clutch housing and a second clutch plate engaged with the rotary member, and the first and second clutch plates being adapted to be clamped between the friction part of the rotary member and the pressure plate. 7. A motorcycle clutch device according to any of claims 1 to 6, wherein the pushing member that generates drag torque is an elastic member which is elastically deformable in the compression direction 8. A motorcycle clutch device according to claim 7, wherein the pushing member that generates drag torque is a compression coil spring.

Full Text

[Title of Document] Specification
[Title of the invention] Motorcycle Clutch Device [Technical field] [0001]
The present invention is related to a clutch device, particularly to a motorcycle clutch device for transmitting power from an input member to an ou^ut member and interrupting the power transmission by the operation of a release mechanism. [Background art] [0002]
Generally, motorcycles such as two-wheeled motor vehicles and ATVs employ a multi-plate clutch device for transmitting and interrupting the power from the engine to the transmission. The multi-plate clutch device includes a clutch housing connected to the engine crankshaft arrangement, an output rotary member connected to the transmission arrangemait, a clutch part for transmitting and interrupting the power therebetween, and a pressure plate for pressing the clutch part The clutch part includes a first plate and a second clutch plate located alternately, with the first clutch plate being engaged with the clutch housing and the second clutch plate being engaged with the output rotary member. [0003]
By pressing the clutch plates against one another by way of a pressing member such as a

spring via the pressure plate, the drive of the crankshaft is transmitted to the transmission. When the
clutch is released to interrupt the power transmission, the operator grips the clutch lever to operate the
release mechanism. The release mechanism releases the pressure of the pressing member to the
clutch plates so that tiie power transmission between the first and second clutch plate is interrupted.
Patent Document 1 Unexamined Patent Publication 2003-222159
[Disclosure of Invention]
[Problems to be solved by the invention]
[0004]
In a vehicle such as a two-wheeled motor vehicle and so on employing the above-mentioned clutch device, the transmission generally employs a dog clutch system, in which it is difficult to shift gear from neutral to first while parking because the dog clutch system transmission does not include a synchronization mechanism. More specifically, when the vehicle parks with the lever in the neutral position, a train of output gears in the transmission does not rotate because the gears are coupled to the tires, while a train of input gears does not rotate because the clutch is disengaged in a power interrupting state so that in many cases the input gears and the output gears do not engage with each other when the driver tries to shift gear from neutral to first [0005]
Therefore, in conventional devices of this type, various components are installed between a plurality of plates in the clutch part in order to generate drag torque in neutral and rotate the input gears

of the transmission. [0006]
However, a conventional device of this type has a complicated structure so that it is troublesome to assemble it and the cost is high. [0007]
It is an object of the present invention to generate drag torque with a simple structure when the clutch is disengaged in order to make it easy to shift gear first neutral to first or others while parking.
[Means for solving problems] [0008]
According to a motorcycle clutch device of claim 1, the device transmits power from an input member to an output member and intermpts the power transmission by the operation of a release mechanism. The device includes a clutch housing, a rotary member, a clutch part, a pressure plate, a release member, a pressing member, and a pushing member to generate drag torque. The clutch housing is coupled to one of the input member and output member. The rotary member is provided within the clutch housing and coupled to the other of the input member and the output member. The clutch part includes at least one plate member to transmit and to interrupt power between the clutch housing and the rotary member. The pressure plate presses the plate member of the clutch part The pressing member includes a disc-like pressing part to press the pressure plate. The release member

releases the pressing load of the pressing member to the pressure plate. The pushing member to generate drag torque is provided between the pressure plate and the pressing part of the pressing member. The pushing member pushes the pressure plate with a load less than the pressing load of the pressing member when the power is ratermpted in the clutch part. [0009]
In this clutch device, the pressure force by the pressing member is applied to the clxitch part
via the pressure plate so that the clutch part is engaged, i.e., in a power transmitting state. In this state,
the power from the input member is input to the clutch housing, for example, and then transmitted to
the rotary member via the clutch part, and finally output to the output member. Alternatively, in a
case in which power from the input member is input to the rotary member, the power is transmitted to
the clutch housing via the clutch part and output to the output member. When the clutch is
released, i.e., in a power interrupting state, the release mechanism operates the pressing member so that the pressure force of the pressing part to the pressure plate is released. [0010]
In this clutch device, the pushing member to generate drag torque pushes the pressure plate with a relatively small load when the clutch is disengaged. Consequently, the clutch part generates drag torque with this load so that the input gears rotate at a low speed in the transmission. As a result, it is easy to shift gears from neutral into other positions while parking. Furthermore, the structure is simple and the assembly is easy because the pushing member to generate drag torque is located

between the disc-like pressing part of the pressing member and the pressure plate. [0011]
According to a motorcycle clutch device of claim 2 depending on claim 1, the pressing member is a diaphragm spring having the pressing part at the radially outer portion, and a lever part at the radially inner portion to release the pressure force of the pressing part while amplifying power from the release mechanism with a lever ratio. [0012]
In this device, the control force of the release mechanism is amplified by the lever ratio of the lever part and is applied to the pressing part so that it is possible to release the clutch with less control force by the lever ratio compared to the conventional clutch device. In addition, the structure of the pressing member is simplified. [0013]
According to a motorcycle clutch device of claim 3 depending on claim 2, the diaphragm spring is constructed such that the pressing part has a radially outer portion pressing the pressure plate, and a radially inner portion supported by the rotary member. A radially inner portion of the lever part is adapted to be moved toward the pressure plate by the release mechanism. [0014]
In this device, the release mechanism operates the radially inner portion of the lever part of diaphragm spring to move the radially outer portion of the pressing part away from the pressure plate.

thereby releasing the pressure force of the pressing part to the pressure plate. [0015]
Since the radially inner portion of the pressing part of the diaphragm spring is supported by the radially outer portion of the rotary member, the structure that supports the diaphragm spring is simplified and the axial lengh of the device is reduced In a typical clutch device for a motor vehicle of the type wherein the radially inner end of the diaphragm spring is driven toward the engine to release the clutch engagement, the radially inner portion of the pressing part of the diaphragm spring is supported by the clutch cover. In this clutch cover support structure, the support portion is a portion that extends radially inward from the radially outer portion of the clutch cover to surround circumferentially the outside of the diaphragm spring. In this structure, it is necessary to ensure a relatively large space in the axial direction to support the diaphragm spring. In the present invention, in contrast, as mentioned before, it is possible to support the diaphragm spring within a relatively small space in the axial direction because the radially outer portion of the rotary member supports the diaphragm spring. [0016]
According to a motorcycle clutch device of claim 4 depending on claim 3, the pressure plate is formed to have a press protrusion protruding in the axial direction at a portion to be pressed by the pressing part The pushing member that generates drag torque has a radially outer portion supported by a radially inner portion of the press protrusion. Therefore, the pushing member for generating drag

torque is held in a position with a simple structure since the pushing member that generates drag torque
is supported by the press protrusion of the pressure plate.
[0017]
According to a motorcycle clutch device of claim 5 depending on claim 2, the diaphragm spring is constructed such that the pressing part has a radially outer portion supported by the rotary member and a radially inner portion pressing the pressure plate. A radially inner portion of the lever part is adated to be moved away from the pressure plate by the release mechanism. [0018]
In the device, the release mechanism operates the radially inner portion of the lever part of diaphragm spring to move the radially inner portion of the pressing part away from the pressure plate, thereby releasing the pressure force of the pressing part to the pressure plate. [0019]
According to a motorcycle clutch device of claim 6 depending on any of claims 1 to 5, the rotary member has a friction part facing the pressure plate at the radially outer portion. The clutch part includes a first clutch plate engaged with the clutch housing and a second clutch plate engaged with the rotary member. The first and second clutch plates are adapted to be clamped between the fiiction part of the rotary member and the pressure plate. [0020]
In the device, the first and second clutch plates constituting the clutch part are clamped

between the friction part of the rotary member and the pressure plate, and the power is transmitted through a driveline of the clutch housing, the first clutch plate, the second clutch plate, and the rotary member in this order. [0021]
According to a motorcycle clutch device of claim 7 depending on any of claims 1 to 6, the pushing member that generates drag torque is an elastic member which is elastically deformable in the compression direction. [0022]
According to a motorcycle clutch device of claim 8 depending on claim 7, the pushing member that generates drag torque is a compression coil spring. [Brief description of drawings] [0023]
Fig. 1 is a cross sectional view of a motorcycle clutch device of the first embodiment of the present invention.
Fig. 2 is a front view of a motorcycle clutch device of the first embodiment of the present invention.
Fig. 3 is a view corresponding to Fig. 1 of the second embodiment of the present invention.
Fig. 4 is a view of showing a modification of the first embodiment of present invention [Explanations of letters or numerals]

[0024]
1.101 clutch housing
2.101 output rotary member
3.101 clutch part
4.101 pressure plate 4c press protrusion
5.101 diaphragm spring 5a, 105a pressing part 5b, 105b lever part
6.101 release member
7.101 urging member for generating drag torque 17,117 input shaft
19,119 support plate 25,26,125,126 clutch plate [Best mode for carrying out the invention] [0025]
[First embodiment]
A motorcycle clutch device shown in Figs. 1 and 2 transmits power from the crankshaft of

the engine to the transmission and interrupts power by the operation of the release mechanism. The clutch device employs a push-type release mechanism wherein the clutch is disengaged by pushing the release bearing inward in the axial direction, and includes a clutch housing 1, an output rotary member 2, a clutch part 3 to transmit and to interrupt the power between the clutch housing 1 and the output rotary member 2, a pressure plate 4, a diaphragm spring 5, a release member 6, and an elastic member 7 to generate drag torque. [0026]
The clutch housing 1 has a disc part 10 and a tubular part 11 extending axially outward (rightward in Fig. 1) from a radially outer end of the disc part 10. An input gear 13 is mounted on the disc part 10 via a plurality of annular mbber members 12. The input gear 13 is engaged with a driving gear (not shown) that is fixed to the crankshaft of the engine. It should be understood that the mbber members 12 are provided to absorb vibrations from the engine, and coil springs can replace them, for example. The tubular part 11 is formed with a plurality of concave portions dented outward in the radial direction on the inner circumference. The tubular part 11 is formed with circumferentially spaced cutouts extending in the axial direction. The cutouts serve to allow an inside lubricating oil to escape radially outward. [0027]

The output rotary member 2 is located within the clutch housing 1. The output rotary member 2 has a disc shape and is formed with a spline 15 at its radially outer end and a spline bore 16 at its radially inner end The spline bore 16 at the radially inner end is engaged with the input shaft 17 of the transmissioa The radially outer portion of the output rotary member 2 is formed with a disc-like friction part 18 as a flange extending radially outward from the axially inner end In addition, the output rotary member 2 is formed with a plurality of support protrusions 2a spaced circumferentially at the radially outer end of an axially outer surface thereof Moreover, the output rotary member 2 is formed with a plurality of bosses 2b on the axially outer surface and radially inward of the support protrusions 2a, the bosses 2b extending in the axial direction and spaced in the circumferential direction. The boss 2b is formed with a faucet joint protrusion 2c at the radially inner end, the protrusion 2c further protruding in the axial directioa [0028]
A support plate 19 is fixed to the bosses 2b of the output rotary member 2 by rivets 20 to support the di^hragm spring 5 on the output rotary member 2. The support plate 19 is an annular member having a radially inner end supported by the faucet joint protrusions 2c of the output rotary member 2. The radially outer portion of the support plate 19 is formed with an annular support protrusion 19a protruding inward in the axial direction, and the radially inner end is formed with, as clear from Fig. 2, a plurality of engagement slots 19b circumferentially spaced. A thrust plate 21 is disposed between a radially inner portion of the input gear 13 and a radially inner portion of the output

rotary member 2.
[0029]

The clutch part 3 includes two first clutch plates 25 and one second clutch plate 26 having an annular shape and alternately stacked in the axial direction. The radially outer end of the first clutch plate 25 is formed with a plurality of engagement protrusions extending outward and engaged with the concave portions on the inner circumference of the tubular part 11 of clutch housing 1. The first clutch plate 25 has opposite surfaces to which friction facings are attached. The spline of the radially inner portion of the second clutch plate 26 is engaged with the spline 15 formed at the radially outer end of the output rotary member 2. [0030]
The pressure plate 4 has an annular shape and is located on the outside of first clutch plate 25 farthest outward in the axial direction. The pressure plate 4 is formed with a spline bore 4a at the radially inner end, with the spline bore 4a being engaged with the outer spline 15 of the output rotary member 2. The pressure plate 4 is formed with an annular protrusion 4b axially extending at a radially outer portion of the axially outer surface, and a press protrusion 4c extending in the axial direction located radially inward of the annular protrusion 4b. The annular protrusion 4b extends outward in the axial direction past the press protrusion 4c.

The diaphragm spring 5 is an annular plate member having a pressing part 5a as a disc spring at its radially outer portion and a lever part 5b at its radially inner portion to release the pressure of the pressing part 5a The lever part 5b is formed with a contact part 5c projecting outward in the axial direction at the radially inner end. The diaphragm spring 5 is located such that the radially outer portion of the diaphragm spring 5 is supported by the inner circumference of the annular protrusion 4b of the pressure plate 4. In the pressing part 5a of the diaphragm spring 5, the radially outer portion is supported by the press protrusion 4c of the pressure plate 4 and the radially inner portion is clamped and supported between the support protrusions 2a of the output rotary member 2 and the support protrusion 19a of the support plate 19. The diaphragm spring 5, as shown in Fig. 1, urges the pressure plate 4 inward in the axial direction with a predetemined pressure force by way of an urging force of the disc spring. Accordingly, the first and second clutch plates 25 and 26 of the clutch part 3 are clamped between the friction part 18 of the output rotaiy member 2 and the pressure plate 4, , [0032]
The lever part 5b of the di^hragm spring 5 is made of a plurality of levers arranged radially. Formed between two circumferentially adjacent levers is a wide slit, and the boss 2b of the output rotary member 2 passes though the slit outward in the axial direction. As mentioned before, since the boss 2b of the output rotary member 2 passes through the slit of lever part 5b of the diaphragm spring 5,

relative rotation is prohibited between the diaphragm spring 5 and the support plate 19 as well as the
output rotary member 2.
[0033]

The release member 6 is an annular plate member and has a radially inner portion holding a release bearing 30, More specifically, the release member 6 is formed with a bearing support part 6a at the axially inner end on the inner circumference, with which an axially inner shoulder portion of an outer race of the release bearing 30 is engaged. Furthemore, an axially inner surface of the release member 6 is configured to press the contact part 5c of the diaphragm spring 5. The release member 6 is formed with a plurality of claws 6b extending radially outward at the radially outer portion, as shown in Fig. 2. The claws 6b are located equidistantly in the circumferential direction and are fitted into the engagement slots 19b of the support plate 19. [0034]
Since the claws 6b of the release member 6 are engaged with the engagement slots 19b, the release member 6 is centered and relative rotation of the release member 6 relative to the diaphragm spring 5, the support plate 19 and the output rotary member 2 is prohibited. [0035]
The elastic member 7 that generates drag torque is located between the pressure plate 4 and

the pressing part 5a of the diaphragm spring 5. The elastic member 7 pushes the pressure plate 4 toward the clutch part 3 with a load less than the pressing load of the diaphragm spring 5 when the clutch is disengaged. The elastic member 7 is a plurality of resin members elastically deformable in the compression directioa A radially outer portion of each elastic member 7 is supported by the radially inner portion of the press protrusion 4c of the pressure plate 4 so that the elastic member 7 is positioned in the radial direction. It is noted that the pressure force of the elastic member 7 is set to generate drag torque to such an extent that the engme does not stop when the clutch is disengaged to shift gears from neutral. [0036]
Next, the operation will be described. [0037]
As mentioned before, the pressing part 5a of the diaphragm spring 5, as shown in Fig, 1, urges the pressure plate 4 inward in the axial direction with a predetermined pressure force by way of an urging force of the disc spring. Accordingly, the first and second clutch plates 25 and 26 of the clutch part 3 are clamped between the fiiction part 18 of the output rotary member 2 and the pressure plate 4. In this state, the clutch is engaged so that the drive input from the crankshaft via the input gear 13 and the mbber members 12 is transmitted to the first clutch plates 25 via the clutch housing 1, then from the second clutch plate 26 to the output rotary member 2, and finally to the input shaft 17 of

the transmission [0038]
When the driver grips the clutch lever, the control force is transmitted to the release bearing 30 via clutch wires to move the release bearing 30 inward in the axial direction. The travel of the release bearing 30 is transmitted to lever part 5b of the diaphragm spring 5 via the release member 6 to move the radially inner portion of the lever part 5b inward in the axial direction. Then, the radially outer portion of the pressing part 5a pivots about the radially intermediate portion of diaphragm spring 5, that is, a portion supported by the support protrusions 2a and 19a, outward in the axial direction, and the radially outer portion of the pressing part 5a moves away from the press protrusion 4c of the pressure plate 4. Consequently, the pressure force toward the pressure plate 4 is released, and the clutch part 3 is disengaged. [0039]
In this clutch disengagement state, the pressure force of the diaphragm spring 5 to the clutch part 3 is released. However, since the elastic member 7 that generates drag torque is provided between the diaphragm spring 5 and the pressure plate 4, a pressing load suflBcientiy smaller than the pressing load of the diaphragm spring 5 is applied to the pressure plate 4. Accordingly, the clutch part 3 generates drag torque in response to the pressing load of the elastic member 7 to generate drag torque. Consequently, the drag torque is transmitted to the input shaft 17 of the transmission so that the input gear is rotated at low speed. As a result, when shifting gears from neutral to first, for example, the

input gears and the output gears in the transmission smoothly go into engagement, thereby making it
easy to shift gears.
[0040]
In the aforementioned operation, when the clutch is released, the control force is lessened by the operation of the lever part 5b. More specifically, for example, if pressure force from the pressing part 5a of the diaphragm spring 5 is expressed as P, the release load R to be applied to the lever part 5b in order to release the pressure force P is expressed as follows:
R=P*(L1/U)
LI: a distance from a fulcrum portion in the radially inner portion of the pressing part to a pressing point in the radially outer portion of the pressing part;
L2: a distance from the fulcrum portion in the radially inner portion of the pressing part to a portion in the lever part contacting the release member.
As a result, the release load is lessened by the lever ratio (L1/L2). Consequently, if the release load is set to one equivalent to that of the conventional device, the pressure load of the pressing part 5a can be increased by the lever ratio, while if the transmission capacity of the clutch is set to one equivalent to that of the conventional device, the number of the clutch plates can be decreased and as a result the clutch device is made more compact. [0041]
By the engagement between the claws 6b of the release member 6 and the engagement slots

19b of the support plate 19 in this device, the release member 6 is centered, which means that the release member 6 is centered with a simple structure and the release operation is smoothly carried out In addition, according to a similar reason, since the release member 6 and the diaphragm spring 5 are prohibited from rotating relative to each other, wear at the contact portions between the di^hragm spring 5 and the release member 6 is restrained. Furthermore, since the support plate 19 is fixed to the output rotary member 2 though the slits of the lever part 5b of the diaphragm spring 5, relative rotation is prohibited between the diaphragm spring 5 and the output rotary member 2 as well as the support plate 19. As a result, wear at contact portions of the support protrusions 2a and 19a and the diaphragm spring 5 is restrained. [0042]
Furthermore, since the radially outer portion of the diaphragm spring 5 is supported by the projection 4b of the pressure plate 4, the diaphragm spring 5 is precisely centered by a simple structure, thereby stabilizing spring characteristics. [0043]
In addition, in this embodiment, although it is necessary to support the diaphragm spring 5 at fte radially intemiediate portion, i.e., the radially inner portion of the pressing part 5a, the radially outer portion of the output rotary member 2 supports the diaphragm spring 5 from radially inside so that it is possible to support the diaphragm spring 5 in a simplified manner and in a smaller space compared to a clutch cover support structure of a conventional vehicle clutch device.

[Second embodiment ]
Fig. 3 shows the second embodiment of the present invention. In the second embodiment, unlike the first embodiment, the clutch device employs a pull-type release mechanism wherein the clutch is disengaged by pulling the release bearing outward in the axial direction. The motorcycle clutch device has a basic structure similar to the first embodiment and includes a clutch housing 101, an output rotary member 102, a clutch part 103 to transmit and to interrupt the power between the clutch housing 101 and the output rotary member 102, a pressure plate 104, a diaphragm spring 105, a release member 106, and an elastic member 107 to generate drag torque. Explanation about the clutch housing 101 and the clutch part 103 will be omitted because the structures are almost the same, and other structures will be described. [0045]
The output rotary member 102 has a disc shape and is formed with a spline 115 at its radially outer end and a spline bore 116 at its radially inner end. The spline bore 116 at the radially inner end is engaged with the input shaft 117 of the transmission. The output rotary member 102 is locked to the input shaft 117 by a nut 117a that is tightened to the tip of the input shaft 117 such that the output rotary member 102 cannot move in the axial direction. The radially outer portion of the output rotary member 102 is formed with a disc-like friction part 118 as a flange extending radially outward from the

axially inner end. Furthermore, the output rotary member 102 is formed with a plurality of bosses 102a at the radially outer portion of the axially outer surface, the bosses 102a being located equidistantly in the circumferential direction and extending in the axial direction At the radially inner end of the boss 102a, a faucet joint protrusion 102b further extending in the axial direction is formed. [0046]
A support plate 119 is fixed to axial surfaces of the bosses 102a of the output rotary member 102 by bolts 120 to support the dighragm spring 105 on the output rotary member 102. The support plate 119 is an annular member having a radially inner end supported by the faucet joint protrusions 102b of the output rotary member 102. The radially outer end of the support plate 119 is formed with an annular support protrusion 119a protruding inward in the axial directioa A thrust plate 121 is provided between a radially inner portion of the input gear 113 and a radially inner portion of the output rotary member 102. [0047]
The pressure plate 104 has an annular shape and is located on the outside of the first clutch plate 125 farthest outward in the axial direction. The pressure plate 104 is formed with a plurality of teeth 104a projecting inward in the axial direction at the radially inner end, being engaged with the outer spline 115 of the output rotary member 102. The pressure plate 104 is formed with an annular projection 104b axially extending at a radially outer portion of the axially outer surface, and the annular

projection 104b is formed with a plurality of slits 104c. The pressure plate 104 is formed with a press
protrusion 104d extending in the axial direction located at the radially inner end of the axially outer
surface. The annular projection 104b extends outward in the axial direction over the press protrusion
104d.
[0048]

The diaphragm spring 105 is an annular plate member having a pressing part 105a as a disc spring at its radially outer portion and a lever part 105b at its radially inner portion to release the pressure of the pressing part 105a. In addition, the pressing part 105a is formed with a plurality of engagement claws 105c at the radially outer end, and the lever part 105b is formed with a plurality of engagement inner teeth 105d at the radially inner end, with the engagement claws 105c being engaged with the slits 104c of the projection 104b of the pressure plate 104. In the pressing part 105a of the di^hragm spring 105, the radially outer portion is supported by the support protrusion 119a of the support plate 119 and the radially inner portion is in contact with the press protrusion 104d of the pressure plate 104. [0049]
The diaphragm spring 105, as shown in Fig. 3, urges the pressure plate 104 inward in the axial direction with a predetermined pressure force by way of an urging force of the disc spring. Accordingly, the first and second clutch plates 125 and 126 of the clutch part 103 are clamped between

the friction part 118 of the output rotary member 102 and the pressure plate 104. [0050]
The lever part 105b of the diaphragm spring 105 is made of a plurality of levers arranged radially. Formed between circumferentially adjacent levers are wider slits, and bosses 102a of the output rotary member 102 pass though the slits outward in the axial directioa [0051]
The release member 106 is an annular member and has a radially inner portion holding a release bearing 130. More specifically, an outer race of the release bearing 130 is fitted into the inner circumference of the release member 106 and a stopper ring 131 is attached to the inner surface of the release bearing 130 outward of the outer race in the axial direction. An axially outer shoulder of the outer race is in contact with the stopper ring 131. The release member 106 is formed with engagement outer teeth 106a on the outer circumference, with which the inner teeth 105d formed at the radially inner end of the dighragm spring 105 are engaged. Furthermore, the release member 106 is formed with a contact part 106b projecting outward at the axially inner end on the outer circumference, and a stopper ring 132 is disposed with a distance outward of the contact part 106b in the axial direction, with the radially inner end of the lever part 105b of the diaphragm spring 105 being sandwiched between the contact part 106b and the stopper ring 132. The release bearing 130 is adapted to be moved outward in the axial direction by the operation of the clutch lever of the

motorcycle not shown.
[0052]

The elastic member 107 that generates drag torque is located between the pressure plate 104 and the pressing part 105a of the diaphragm spring 105. The elastic member 107 pushes the pressure plate 104 toward the clutch part 103 with a load less than the pressing load of the diaphragm spring 105 when the clutch is disengaged. The elastic member 107 is a plurality of resin members elastically deformable in the compression direction, and each of the elastic members 107 is supported by the concave portions formed radially outward of the press protrusion 104d of the pressure plate 104 so that the elastic member 107 is positioned in the radial direction. [0053]
Next, the operation will be described. [0054]
As mentioned before, the pressing part 105a of the diaphragm spring 105, as shown in Fig. 3, urges the pressure plate 104 inward in the axial direction with a predetermined pressure force by way of an urging force of the disc spring. Accordingly, the first and second clutch plates 125 and 126 of the clutch part 103 are clamped between the fiiction part 118 of the output rotary member 102 and the pressure plate 104. In this state, the clutch is engaged so that the drive input from the crankshaft via

the input gear 113 and the mbber members 112 is transmitted to the first clutch plates 125 via the clutch housing 101, then from the second clutch plate 126 to the output rotary member 102, and finally to the input shaft 117 of the transmission. [0055]
When the driver grips the clutch lever, the control force is transmitted to the release bearing 130 via clutch wires to move the release bearing 130 outward in the axial direction. The travel of the release bearing 130 is transmitted to lever part 105b of the dighragm spring 105 via the release member 106 to move the radially inner portion of the lever part 105b outward in the axial direction. Then, the radially inner portion of the pressing part 105a pivots about the radially outer portion of diaphragm spring 105, i.e,, a portion supported by the support protrusion 119a of the support plate 119, outward in the axial direction, and the pressing part 105a moves away from the press protrusion 104d of the pressure plate 104. Consequently, the pressure force toward the pressure plate 104 is released, and the clutch part 103 is disengaged. [0056]
Although the pressure force of the dighragm spring 105 to the clutch part 103 is released in the clutch release state mentioned before, since the elastic member 107 that generates drag torque is provided between the diaphragm spring 105 and the pressure plate 104, a pressing load sufficiently smaller than the pressing load of the diaphragm spring 105 is applied to the pressure plate 104. Accordingly, the clutch part 103 generates drag torque in response to the pressing load of the elastic

member 107 that generates drag torque. Consequently, the drag torque allows the input gears to rotate at low speed As a result, when shifting gear from neutral to first, for example, the input gears and the output gears in the transmission smoothly go into engagement, thereby making it easy to shift gear. [0057]
Similarly to the first embodiment, v^en the clutch is released, the control force is lessened by the operation of the lever part 105b. More specifically, for example, if pressure force from the diaphragm spring 105 is expressed as P, the release load R to be applied to the lever part 105b in order to release the pressure force P is expressed as follows:
R=P*(L3/L4)
L3: a distance from a fulcrum portion in the radially outer portion of the pressing part to a pressing point in the radially inner portion of the pressing part;
L4: a distance from a fialcrum portion in the radially outer portion of the pressing part to a portion in the lever part contacting the release member.
In other words, the release load is lessened by the lever ratio (L3/L4), [0058]
Since the inner teeth 105d at the tip of the lever part 105b and the outer teeth 106a of the release member 106 are engaged in this device in order to prohibit the relative rotation between the dighragm spring 105 and the release member 106, wear at the contact portions between the

diaphragm spring 105 and the release member 106 is restrained. Furthermore, since the radially outer portion of the dighragm spring 105 is supported by the projection 104b of the pressure plate 104, the dighragm spring 105 is precisely centered with a simple structure, thereby stabilizing spring characteristics. Furthermore, since the claws 105c at the radially outer end of the diaphragm spring 105 are engaged with the slits 104c of the pressure plate 104, relative rotation between them is prohibited, thereby restraining wear at their contact portions. [0059] [Other embodiments]
(a) Although the resin that is elastically deformable in the compression direction is used as an
elastic member to generate drag torque in the above embodiment, a compression coil spring may be
used. The structure of this embodiment is shown in Fig. 4. In the embodiment shown in Fig. 4, in
place of the resin urging member 7 in the first embodiment, compression coil springs T are used and
the pressure plate 4 is formed with protrusions 4d to support the coil springs T. Other components are
the same as those of the first embodiment.
[0060]
(b) Although in the aforementioned embodiment the drive is input from the input gear and is
output to the output rotary member, the present invention can be applied to another case wherein the
driveline is reversed as well.

In a motorcycle clutch device according to the present invention, drag torque is generated with a simple structure when the clutch is disengaged so that it is easy to shift gears from neutral to first while parking.

[Title of Document] Claims
1. A motorcycle clutch device for transmitting power from an input member to an output
member and interrupting power transmission by an operation of a release mechanism, comprising:
a clutch housing being coupled to one of the input member and the output member;
a rotary member being provided within the clutch housing and coupled to the other of the input member and the output member,
a clutch part including at least one plate member to transmit and to interrupt power between the clutch housing and the rotary member,
a pressure plate being configured to press the plate member of the clutch part;
a pressing member including a disc-like pressing part to press the pressure plate;
a release member being configured to release the pressing load of the pressing member to the pressure plate; and
a pushing member being configured to generate drag torque provided between the pressure plate and the pressing part of the pressing member, the pushing member pushing the pressure plate with a load less than the pressing load of the pressing member when the power is interrupted in the clutch part
2. A motorcycle clutch device according to claim 1, wherein the pressing member is a
diaphragm spring having the pressing part at the radially outer portion, and a lever part at the radially

inner portion to release the pressure force of the pressing part while amplifying power from the release mechanism with a lever ratio.
3. A motorcycle clutch device according to claim 2, wherein the diaphragm spring is
constructed such that the pressing part has a radially outer portion pressing the pressure plate and a
radially inner portion supported by the rotary member, and
a radially inner portion of the lever part is ad^ted to be moved tow^ard tiie pressure plate by the release mechanism.
4. A motorcycle clutch device according to claim 3, wherein the pressure plate is formed with
a press protrusion protruding in the axial direction at a portion to be pressed by the pressing part, and
the pushing member that generates drag torque has a radially outer portion supported by a radially inner portion of the press protrusion.
5. A motorcycle clutch device according to claim 2, wherein the diaphragm spring is
constructed such that the pressing part has a radially outer portion supported by the rotary member and
a radially inner portion pressing the pressure plate, and
a radially inner portion of the lever part is adapted to be moved away from the pressure plate by the release mechanism.

6. A motorcycle clutch device according to any of claims 1 to 5, wherein the rotary member
has a friction part facing the pressure plate at the radially outer portion, and
the clutch part includes a first clutch plate engaged with the clutch housing and a second clutch plate engaged with the rotary member, and the first and second clutch plates being adapted to be clamped between the friction part of the rotary member and the pressure plate.
7. A motorcycle clutch device according to any of claims 1 to 6, wherein the pushing member
that generates drag torque is an elastic member which is elastically deformable in the compression
direction
8. A motorcycle clutch device according to claim 7, wherein the pushing member that
generates drag torque is a compression coil spring.

Documents:

5716-CHENP-2007 AMENDED CLAIMS 14-10-2011.pdf

5716-CHENP-2007 CORRESPONDENCE OTHERS 17-06-2011.pdf

5716-CHENP-2007 FORM-3 14-10-2011.pdf

5716-CHENP-2007 OTHER PATENT DOCUMENT 14-10-2011.pdf

5716-CHENP-2007 POWER OF ATTORNEY 14-10-2011.pdf

5716-CHENP-2007 EXAMINATION REPORT REPLY RECEIVED 14-10-2011.pdf

5716-chenp-2007-abstract.pdf

5716-chenp-2007-claims.pdf

5716-chenp-2007-correspondnece-others.pdf

5716-chenp-2007-description(complete).pdf

5716-chenp-2007-drawings.pdf

5716-chenp-2007-form 1.pdf

5716-chenp-2007-form 18.pdf

5716-chenp-2007-form 3.pdf

5716-chenp-2007-form 5.pdf

5716-chenp-2007-pct.pdf

« Previous Patent

Next Patent »

Patent Number

250006

Indian Patent Application Number

5716/CHENP/2007

PG Journal Number

48/2011

Publication Date

02-Dec-2011

Grant Date

28-Nov-2011

Date of Filing

12-Dec-2007

Name of Patentee

EXEDY CORPORATION

Applicant Address

1-1, KIDAMOTOMIYA 1-CHOME, NEYAGAWA-SHI, OSAKA 572-8570, JAPAN.

Inventors:

#	Inventor's Name	Inventor's Address
1	YAMADA, TOSHIYUKI	C/O EXEDY CORPORATION, 1-1, KIDAMOTOMIYA 1-CHOME,, NEYAGAWA-SHI, OSAKA 572-8570, JAPAN.
2	IMANISHI, YOSHIO	C/O EXEDY CORPORATION, 1-1, KIDAMOTOMIYA 1-CHOME,, NEYAGAWA-SHI, OSAKA 572-8570, JAPAN.

PCT International Classification Number

F16D13/71

PCT International Application Number

PCT/JP2006/308952

PCT International Filing date

2006-04-28

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2005-139488	2005-05-12	Japan