Title of Invention

"A CONTINUOUSLY VARIABLE TRANSMISSION OF MAIN SHAFT FOR AN ENGINE

Abstract

A continuously variable transmission of main shaft for an engine comprising: a drive face (29) rotatably supported by a transmission main shaft (21); and a centrifugal mechanism (51). a gear (25), rotatably supported by said transmission main shaft (21), for transmitting a drive force to said drive face (29); a driven face (30) rotatably supported by said transmission main shaft (21); cone holders (31, 56) movable along said transmission main shaft (21); double cone supporting shafts (37) supported by said cone holders (31, 56) placed so as to extend along a cone generating line centered on said transmission main shaft (21); and double cones (39),each having first and second cones (40), (41) sharing a bottom face and being rotatably supported by each of said double cone supporting shafts (37), wherein said first cone (40) is brought in contact with said drive face (29) and said second cone (41) is brought in contact with said driven face (30); characterized in that said drive face (29) and said gear (25) are contained in said cone holders (31, 56) placed so as to cover said transmission main shaft (21), and a tooth face of said gear (25) faces to a window (312) opened in said cone holders (31, 56).

Full Text

[Technical Field of the Invention] The present invention relates to a continuously variable transmission including double cones each having a first cone in contact with a drive face and a second cone in contact with a driven face, wherein a speed change ratio is changed by changing the contact positions between the first cone and the drive face and between the second cone and the driven face. [0002] [Related Art] Such a continuously variable transmission is known from, for example, Japanese Patent Publication No. Sho 47-447. [0003] [Problem to be Solved by the Invention] In the above-described related art continuously variable transmission, since a transmission main shaft extends outward from a casing for inputting a drive force for an engine, there occurs a disadvantage in enlarging the axial size of the continuously variable transmission* It may be considered to drive a driven gear provided at the axial center of the transmission main shaft by a drive gear i provided on a crank shaft. In this case, however, there occurs another disadvantage that the driven gear unnecessarily stirs oil stored in the bottom portion of the casing of the transmission and thereby a loss in power due to the stirring resistance is increased. [0004] To cope with such an inconvenience, it may be considered that the lower portion of the driven gear is covered with an oil preventive member for preventing unnecessary stirring of oil. In this case, however, there occurs another disadvantage in that the number of parts is increased by provision.of the oil preventive member. [0005] In view of the foregoing, the present invention has been made, and an object of the present invention is to provide a continuously variable transmission capable of preventing unnecessary stirring of oil by a transmission input gear without the need of provision of any special oil preventive member. [0006] [Means for Solving the Problem] To achieve the above object, according to an invention described in claim 1, there is provided a continuously variable transmission including: a drive face rotatably supported by a transmission main shaft; a transmission input gear rotatably supported by the transmission main shaft and transmitting a drive force to the drive face;'a driven face rotatably supported by the transmission main shaft; cone holders movable along the transmission main shaft; double cone supporting shafts supported by the cone holders in such a manner as to extend along a cone generating line centered on the transmission main shaft; and double cones, each including first and second cones sharing a bottom face and being rotatably supported by each of the double cone supporting shafts, wherein the first cone is brought in contact with the drive face and the second cone is brought in contact with the driven face;wherein the drive face and the transmission input gear are contained in the cone holders formed in such a manner as to cover the transmission main shaft, and a tooth face of the transmission input gear faces to a window opened in the cone holders. ' [0007] According to an invention described in claim -2, there is provided a continuously variable transmission according to claim 1, wherein the drive face and a i centrifugal mechanism are respectively disposed on one side and the other side of the transmission main shaft in the axial direction while putting the transmission input gear therebetween, and the cone holders are moved along the transmission main shaft by operation of the centrifugal mechanism. [0008] [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described 'with reference to the accompanying drawings. [Brief Description of the Drawings] [Fig. 1] A vertical sectional view of a power unit for a vehicle. [Fig. 2] An enlarged view of an essential portion of Fig. l. [Fig. 3] A sectional view taken on line 3-3 of Fig. 2. [Fig. 4] . • A sectional view taken on line 4-4 of Fig. 2. Figs. 1 to 4 show' an embodiment of the present invention, wherein Fig. 1 is a vertical sectional view of a power unit for a vehicle; Fig. 2 is an enlarged view of an essential portion of Fig. 1; Fig. 3 is a sectional view taken on line 3-3 of Fig. 2; and Fig. 4 is a sectional view taken on line 4-4 of Fig. 2. " " [0010] A power unit P, which is to be mounted on a motorcycle, includes an engine E and a casing 1 containing a continuously variable transmission T (see Fig. 1). The casing 1 is divided into three parts, a center casing 2, a V left casing 3 connected to the left face of the center casing 2, and a right casing 4 connected to the right face of the center casing 2. A crank shaft 6 supported by the center casing 2 and the left casing 3 through a pair of ball bearings 5, 5 is connected through a connecting rod 9 to a piston 8 slidably fitted in a cylinder block 7 supported by the center casing 2 and the left casing 2. [0011] A power generator 10, provided at the left end of the crank shaft 6, is covered with a power generator cover 11 connected to the left face of the left casing 3. A drive gear 12 is relatively rotatably supported around the outer periphery of the right end of the crank shaft 6 extending in the right casing 4. The drive gear 12 can be connected to the crank shaft 6 by means of an automatic centrifugal clutch 13 provided at the right end of the crank shaft 6. [0012] : '- As can be seen from Figs. 1, 2, a transmission mainf shaft 21 of the continuously variable transmission T includes an inner side output shaft 22, and a sleeve-like input shaft 23 relatively rotatably fitted around the outer periphery of the output shaft 22 through a needle bearing 24. Both the ends of the output shaft 22 are hung between the left casing 3 and the right casing 4, A driven gear 25 meshing with the drive gear 12 is fixed on the input shaft 23. The driven gear 25 includes an inner gear half 26 |spline-connected to the input shaft 23, and an outer gear half 27 slightly, relatively rotatably connected to the inner gear half 26 through a plurality of rubber dampers 28 and meshing with the drive gear 12. When an engine torque transmitted from the drive gear 12 to the input shaft 23 through the driven gear 25 is changed, shock due to the change in the engine torque is reduced by deformation of the rubber dampers 28. [0013] A drive face 29 having an annular contact portion 29i facing radially outward is spline-connected around the outer periphery of the input shaft 23, and a driven face 30 having an annular contact portion 30j facing radially inward is relatively rotatably supported around the output shaft 22. [0014] A first cone holder 31 formed in an approximately conical shape is supported around the outer periphery of a boss portion 302 of the driven face 30 through a needle bearing 32 in such a manner as to be relatively rotatable and to be axially slidable. As can be seen from Figs. 1 to 3, a torque cam mechanism 33 for stopping rotation of the first cone holder 31 with respect to the casing 1 includes a pin 34 radially planted in the outer periphery of the first cone holder 31, a roller 36 rotatably supported by the pin 34 through a ball bearing 35, and a guide groove 4i formed in the .inner wall face of the right casing 4 for guiding the roller 36. The guide groove 4j is inclined by an angle a with respect to an axial line L of the transmission main shaft 21. [0015] A plurality of double cone supporting shafts 37 are provided in such a manner as to cross a plurality of windows 31i formed in the first cone holder 31. A double cone 39 is rotatably supported by each double cone supporting shaft 37 through needle bearings 38. The double cone supporting shafts 37 are disposed along a cone generating line centered on the axial line L of the transmission main shaft 21, and cross a gap between the contact portion 291 of the drive face 29 and the contact portion 30! of the driven face 30. Each double cone 39 includes a first cone 40 and a second cone 41 which have a common bottom face. The contact portion 29i of the drive face 29 is brought in contact with the first cone 40, while the contact portion 30i of the driven face 30 is brought in contact with the second cone 41. [0016] A window 33.2 is opened in the upper portion of the first cone holder 31 facing to the crank shaft 6. The tooth face of the driven gear 25 contained in the first cone holder 31 faces to the window 312, and the drive gear 12 meshes with the driven gear 25 through the window 312. [0017] A centrifugal mechanism 51 is provided on the right side of the driven gear 25 for changing the speed change ratio of the continuously variable transmission T by axially sliding the first cone holder 31 in accordance with a rotational speed of the input shaft 23. The centrifugal mechanism 51 includes a sleeve 52 fixed around the outer periphery of the input shaft 23, a cam member 54 slidably fitted around the outer periphery of the sleeve 52 through a bush 53, and a plurality of centrifugal weights 55. disposed between a fixed cam face 26j formed on the right face of the inner gear half 26 of the driven gear 25 and a movable cam face 54j formed on the left face of the cam member 54. The outer periphery of the second cone holder 56 covering the centrifugal mechanism 51 is fixed by a clip 57 at the right end of the first cone holder 31, and the inner periphery of the second cone holder 56 is supported by the cam member 54 through a ball bearing 58. [0018] The first and second cone holders 31, 56 cooperates to define a space surrounding the transmission main shaft 21. The space contains the driven gear 25, the drive face 29, and the centrifugal mechanism 51. The space is also communicated to the inner space of the casing 1 through the window 312 to which the tooth face of the driven gear 25 faces and the windows 31i supporting the double cones 39. [0019] A stepped collar 59 fitted to the right end of the sleeve 52 is supported around the outer periphery of the right end of the output shaft 22 through a ball bearing 60,, and the right face of the ball bearing 60 is fixed to the output shaft 22 by a cotter 61. The transmission main shaft 21 including the output shaft 22 and the input shaft 23 is supported by the right casing 4 through a ball s' bearing 62 fitted around the outer periphery of the input shaft 23. A spring 64 is provided in a contracted state between a spring retainer 63 supported by the ball bearing 62 and the second cone holder 56. The second cone holder 56 and the first cone holder 31 are biased in the left direction by an elastic force of the spring 64. [0020] When the rotational speed of the input shaft 23 is increased, the centrifugal weights 55 are moved radially outward by centrifugal forces applied to the centrifugal weights 55, and both the cam faces 26!, 54i are pressed by the centrifugal weights 55. As a result, the cam member 54 is moved in the right direction against an elastic force of the spring 64, so that the second cone holder 56 connected to the cam member 54 through the ball bearing 58 and the first cone holder 31 are moved in the right direction. [0021] A pressure adjusting cam mechanism 67 is provided between the right end of an output gear 66 spline-connected to the left end of the output shaft 22 and fixed thereto by r a cotter 65 and the left end of the driven face 30. ..As can be seen from Fig. 4, the pressure adjusting cam mechanism 67 is so configurated that balls 68 are each held between a plurality of recessed portions 66Z formed at the right end of the output gear 66 and a plurality of recessed portions 303 formed at the left end of the driven face 30-, and a disc spring 69 for imparting a rightward biasing pre-load to the driven face 30 is interposed between the output gear 66 and the driven face 30. When the driven face 30 is applied with a torque and relatively rotated with respect to the output gear 66, it is biased in the direction being separated from the output gear 66 (right direction, in the figure). [0022] Referring again to Fig. I, a thir,d reduction gear "• » 71 is rotatably supported by the left casing 3 through a ball bearing 70, and the left end of the output .shaft 22 is coaxially supported by the third reduction gear 71 through a needle bearing 72 and a ball bearing 73. A reduction shaft 75 is supported by the left casing 3 and the center casing 2 through a pair of ball bearings 74, 74, and first and second reduction gears 76, 77 provided on the reduction , shaft 75 mesh with the output gear 66 and the third reduction gear 71, respectively. A drive sprocket 79, around which an endless chain 78 is wound, is provided at the leading end of the shaft portion of the third reduction f.' i gear 71 projecting outward from the left casing 4. The rotation of the output shaft 22 is thus transmitted to a drive wheel through the output gear 66, the first, second, third reduction gears 76, 77, 71, the drive sprocket 79, and the endless chain 78. I [0023] An oil passage 42 formed in the right casing 4 is communicated to an oil passage 22i axially passing through the output shaft 22, and each portion of the continuously variable transmission T is lubricated by an oil supplied from the oil passage 22i to the inner space surrounded by the first and second cone holders 31, 56. [0024] Next, the function of the embodiment of .the present invention having the above-described configuration will be described. [0025] As shown in Fig. 2, a distarice A between the contact portion 29j. of the drive face 29 and the axial line L of the transmission main shaft 21 is constant, while a distance B between the contact portion 29i of the drive face 29 and the double cone supporting shaft 37 is variable (BL, BT). A distance C between the contact portion 30! of the driven face 30 and the double cone supporting shaft 37 is variable (CL/ CT), while a distance D between the contact portion 30x of the driven face 30 and the axial line L of the transmission main shaft 21 is constant. [0026] A speed change ratio R is given by R = NDR/NDN = (B/A)X(D/C) where NDR is a rotational speed of the drive face 29 and NDN is a rotational speed of the driven face 30. [0027] When the engine E is rotated at a low speed, the rotational speed of the driven gear 25 driven by the drive gear 12 is low. At this time, as shown on the upper half in Fig. 2, since centrifugal forces applied to the centrifugal weights 55 of the centrifugal mechanism 51 are low, the second cone holder 56 and the first cone holder 31 are moved in the left direction by the elastic force of the spring 64. As the first cone holder 31 is moved in the left direction, the contact portion 29i of the drive face 29 is moved on the bottom face side of the first cone 40 of the double cone 39 and thereby the distance B is increased to the maximum value BL, while the contact portion 30a of V the driven face 30 is moved on the vertex side of the second cone 41 of the double cone 39 and thereby the distance C is decreased to the minimum value CL When the distance B is increased to the maxim value BL and the distance C is decreased to the minimum value CL as described above (the distances A, D are constant), the speed change ratio R is increased into a LOW ratio. [0029] On the other hand, when the engine E is rotated at a high speed, the rotational speed of the driven gear 25 driven by the drive gear 12 is high. At this time, as shown on the lower half in Fig. 2, since centrifugal forces applied to the centrifugal weights 55 of the centrifugal mechanism 51 are high, the second cone holder 56 and the first cone holder 31 are moved in the right direction against the elastic force of the spring 64 by the action of the centrifugal weights 55 moved radially outward by the centrifugal forces. As the first cone holder 31 is moved » in the right direction, the contact portion 29i of the f drive face 29 is moved on the vertex side of the first cone 40 of the double cone 39 and thereby the distance B is decreased to the minimum value BT, while the contact portion 301 of the driven face 30 is moved on the bottom face side of the second cone 41 of the double cone 39 and thereby the distance C is increased to the maximum value [0030] When the distance B is decreased to the minimum value BT and the distance C is increased to the maximum value CL as described above (the distances A, D are constant), the speed change ratio R is decreased into a TOP ratio. [0031] In this way, the speed change ratio of the continuously variable transmission T can be continuously changed between the LOW and TOP sides in accordance with the rotational speed of the engine E. Furthermore, since the speed change ratio is automatically controlled by the centrifugal mechanism 51, it becomes1 possible to reduce the cost due to simplification of the structure and to reduce the size of the continuously variable transmission T as compared with the case of provision of a speed change controller for manually controlling speed change from the outside of the casing 1 or of provision of an electronic speed change controller. [0032] The rotation of the drive dace 29 is thus transmitted at a specified speed change ratio R to the driven face 30 through the double cones 39 and the rotation of the driven face 30 is transmitted to the output gear 66 through the pressure adjusting cam mechanism 67. At this time, when a relative rotation is generated between the driven face 30 and the output gear 66 by a torque applied to the driven face 30, the driven face 30 is biased in the direction being separated from the output gear 66 by the pressure adjusting cam mechanism 67. The biasing force generates, in co-operation with the biasing force by the disc spring 69, a face pressure for pressing the contact portion 29j of the drive face 29 to the first cone 40 of the double cone 39 and a face pressure for pressing the contact portion SOj of the driven face 30 to the second cone 41 of the double cone 39. [0033] Incidentally, while the biasing force by the pressure adjusting cam mechanism 67 presses the output gear 66 in the left direction, the leftward pressing force is transmitted to the output gear 22 because the left end of i the output gear 66 is fixed to the left end of the output shaft 22 by the cotter 65. Furthermore, while the biasing force by the pressure adjusting cam mechanism 67- presses the driven face 30 in the right direction, the rightward pressing force is transmitted from the driven face 30 to the right end of the output shaft 22 through the double cones 39, the drive face 29, the inner gear half 26, the sleeve 52, the ball bearing 62, the collar 59, the ball bearing 60, and the cotter 61. [0034] Accordingly, the load applied from the pressure adjusting cam mechanism 67 to the output gear 66 and the driven face 30 for respectively pressing them in the left and right directions, acts as a tensile load for the output shaft 22, and the tensile load is canceled by an internal stress of the output shaft 22. As a result, -the pressing load of the pressure adjusting cam mechanism 67 is not transmitted to the casing 1. This eliminates the need of reinforcing the strength of the casing 1 to such an extent as to withstand the pressing load, thereby reducing the weight of the continuously variable transmission T. -Furthermore, since the drive face 29 and the driven face 30 are biased only by one pressure adjusting cam mechanism 67, it is possible to reduce the number of parts and the cost as compared with the case where they are biased by separate pressure cam mechanisms 67 respectively. [0035] Although the first cone holder 31 is intended to be rotated around the transmission main shaft 21 by a reaction force to the transmission torque of the drive face 29 upon speed change operation by the continuously variable transmission T, the reaction force to the transmission torque is received by engagement between the-roller 36 of the torque cam mechanism 33 supported by the first cone holder 31 and the guide groove 4j formed in the right casing 4, and consequently the first cone holder 31 can be slid in the axial direction without any rotation. [0036] When an engine torque is rapidly increased for rapid acceleration during running of a vehicle, a reaction force to a transmission torque, whidh'is applied to the first cone holder 31, is increased with the rapid increase » in the engine torque. As a result, as shown in Fig. 3, the roller 36 is brought in press-contact with the wall face of the inclined guide groove 4i by a load F, and the first cone holder 31 is biased on the left side (on the LOW ratio side) in Fig. 2 by a component Fj of the load F applied in the direction of the guide groove 4j. Namely, the speed change ratio is automatically changed on the LOW ratio side by the action of the torque cam mechanism 33, so that the so-called kick-down effect is exhibited' and the vehicle can be effectively accelerated. [0037] Furthermore, the speed change ratio control upon kick-down can be automatically performed by the torque cam mechanism 33 in accordance with a change in engine torque without the need of provision of any special speed change controller, so that it is possible to reduce the cost due •• * to simplification of the structure and to reduce the size of the continuously variable transmission T. In addition, the change characteristic of the speed change ratio can be easily adjusted only by changing the shape of the guide groove 4i of the torque cam mechanism 33. [0038] : '- Although the lower portions of the first and second, cone holders 31, 56 of the continuously variable transmission T are immersed in oil stored in the bottom portion of the casing 1, a large amount of oil does not permeate from the bottom portion of the casing 1 into the ' inner space surrounded by the first and second cone holders 31, 56 because the windows 31i for supporting the double cones 39 and the window 322 to which the gear tooth of the driven gear 25 faces are positioned higher than an oil level OL 'of the oil (see Fig. 2). Even if a lubricating oil is supplied from the oil passage 22i passing through the output shaft 22 into the inner space surrounded by the first and second cone holders 31, 56, the oil is scattered outward by the centrifugal force generated by rotation of the driven gear 25. As a result, the minimum oil required for lubrication is held in the inner space surrounded by the first and second cone holders 31, 56. [0039] Since the driven gear 25 stirs only a small amount of oil as described above, it is possible to suppress a loss in power due to stirring of unnecessary oil at minimum. Furthermore, since the oil permeation is preventive by the first and second done holders 31, 56, it is possible to eliminate the need of provision of any special oil preventive member and hence to reduce the number of parts. [0040] As described above, the arrangement of the driven gear 25 in the space defined by the first and second cone holders 31, 56 makes it possible to reduce oil stirring resistance as compared with the case of arrangement of the driven gear 25 outside the space. Furthermore, the arrangement of the drive face 29 and the centrifugal mechanism 51 on the right and left sides of the driven gear 25 respectively makes it possible to make use of the capacity of the space and hence to make compact the continuously variable transmission T. [0041] While the embodiment of the present invention has been described in detail, such description is for illustrative purposes only, and it is to be understood that changes and modifications may be made without departing from the scope and spirit of the present invention. [0042] For example, although the cone holder is divided into two parts, the first cone holde:r"31 and the second cone holder 56, and the window 312 to which the tooth face , of the driven gear 25 faces is formed in the first cone holder 31, the shape of the cone holder, the division of the member, positioning of the window, and the like may be freely changed. [0043] [Effect of the Invention] As described above, according to the invention described in claim 1, a drive face and a transmission input gear are contained in cone holders formed in such a manner I as to cover a transmission main shaft, and the tooth face of the transmission input gear faces to a window formed in the cone holders. Consequently, it becomes possible to make compact the axial size of the continuously variable transmission as compared with a case of provision of the transmission input gear outside the cone holders, and to prevent the transmission input gear from being immersed in oil by the cone holders for avoiding an increase in oil stirring resistance and hence to eliminate the need of provision any special oil preventive member resulting in the reduced number of parts. [0044] According to the invention described in claim 2, the drive face and a centrifugal mechanism are disposed on one side and the other side of the transmission main shaft in the axial direction while putting a transmission input gear therebetween and the cone holders are moved along the transmission main shaft by operation of the centrifugal mechanism. Consequently, it becomes possible to automatically adjust a speed change ratio without the need of provision of any controller for adjusting a speed change ratio from the outside of the transmission, and also to make compact the transmission. | [Explanation of Characters] 21 : transmission main shaft 25 : driven gear (transmission input :gear) 29 : drive face 30 : driven face 31 : first cone holder (cone holder) 312: window 37 :double cone supporting shaft 39 : double cone 40 :first cone 41 :second cone 51 :centrifugal mechanism 56 :second cone holder (cone holder) 3 [Claim 1] A continuously variable transmission comprising: a drive face (29) rotatably supported by a transmission main shaft (21); a transmission input gear (25), rotatably supported by said transmission main shaft (21), for transmitting a drive force to said drive face (29); a driven face (30) rotatably supported by said transmission main shaft (21); ' ~ cone holders (31, 56) movable along said transmission main shaft (21); double cone supporting shafts (37) supported..by said cone holders (31, 56) in such a manner as to extend *along a cone generating line centered on said transmission * i main shaft (21); and double cones (39), each including first and second cones (40), (41) sharing a bottom face and being rotatably supported ±>y each of said double cone supporting shafts » (37), wherein I said first cone (40) is brought in contact with said drive face (29) and said second cone (41) is brought in contact with said driven face (30); wherein said drive face (29) and said transmission input gear (25) are contained in said cone holders (31, 56) formed in such a manner as to cover said transmission main shaft (21), and a tooth face of said transmission input gear (25) faces to a window (312) opened in said cone holders (31, 56). [Claim 2] . A continuously variable transmission according to claim 1, wherein said drive face (29) and a centrifugal" mechanism (51) are respectively disposed on one side and the other side of said transmission "main shaft (21) in the', axial direction while putting said transmission input gear (25) therebetween, and said cone holders (31, 56) are moved along said transmission main shaft (21) by operation-of said centrifugal mechanism (51). 3. A continuously variable transmission substantially as herein described with reference to and as illustrated in the accompanying drawings.

Documents:

2249-del-1996-abstract.pdf

2249-del-1996-claims.pdf

2249-del-1996-correspondence-others.pdf

2249-del-1996-correspondence-po.pdf

2249-del-1996-description (complete).pdf

2249-del-1996-drawings.pdf

2249-del-1996-form-1.pdf

2249-del-1996-form-13.pdf

2249-del-1996-form-19.pdf

2249-del-1996-form-2.pdf

2249-del-1996-form-3.pdf

2249-del-1996-form-4.pdf

2249-del-1996-form-6.pdf

2249-del-1996-gpa.pdf

2249-del-1996-petition-138.pdf