Title of Invention	"A PULLEY STRUCTURE OF V-BELT TYPE AUTOMATIC TRANSMISSION DEVICE FOR A SCOOTER TYPE MOTORCYCLE"
Abstract	This invention concerns a pulley structure of a V-belt type automatic transmission device for a scooter type motorcycle, said transmission device comprising: a fixed pulley half rotatably supported on a rotational shaft; a movable pulley half disposed opposite to said fixed pulley half for holding a V-belt therebetween, said movable pulley half being slidably, rotatably supported on a fixed pulley cylindrical shaft; and a torque cam mechanism for converting a turning motion of said movable pulley half relative to said fixed pulley half into an axial thrust of said movable pulley half; characterised in that said torque cam mechanism has movable side cam portions and fixed side cam portions to be meshed with said movable side cam portions, said movable side cam portions being formed at an edge portion of a movable pulley cylindrical shaft of said movable pulley half so as to axially extend therefrom, said fixed cam portions arc provided on a clutch drive plate fixed on the end portion of said fixed pulley cylindrical shaft and being formed at an end portion of said fixed pulley cylindrical shaft so as to extend in the peripheral direction, and a clearance in the rotational direction between each of said movable pulley side cam portions and the corresponding one of said fixed pulley aide com portions is made small.

Title of Invention

"A PULLEY STRUCTURE OF V-BELT TYPE AUTOMATIC TRANSMISSION DEVICE FOR A SCOOTER TYPE MOTORCYCLE"

Abstract

This invention concerns a pulley structure of a V-belt type automatic transmission device for a scooter type motorcycle, said transmission device comprising: a fixed pulley half rotatably supported on a rotational shaft; a movable pulley half disposed opposite to said fixed pulley half for holding a V-belt therebetween, said movable pulley half being slidably, rotatably supported on a fixed pulley cylindrical shaft; and a torque cam mechanism for converting a turning motion of said movable pulley half relative to said fixed pulley half into an axial thrust of said movable pulley half; characterised in that said torque cam mechanism has movable side cam portions and fixed side cam portions to be meshed with said movable side cam portions, said movable side cam portions being formed at an edge portion of a movable pulley cylindrical shaft of said movable pulley half so as to axially extend therefrom, said fixed cam portions arc provided on a clutch drive plate fixed on the end portion of said fixed pulley cylindrical shaft and being formed at an end portion of said fixed pulley cylindrical shaft so as to extend in the peripheral direction, and a clearance in the rotational direction between each of said movable pulley side cam portions and the corresponding one of said fixed pulley aide com portions is made small.

Full Text	The present invention relates to a pulley structure of a V-belt type automatic transmission device for a scooter type motorcycle and particularly to a torque cam mechanism and a pulley structure of the V-belt type automatic transmission. A V-belt type automatic transmission includes a drive pulley, a driven pulley, and an endless belt which is V-shaped in cross-section and is wound between the drive pulley and the driven pulley, wherein a power is transmitted by automatically adjusting an effective radius of each pulley in accordance with an engine speed. In each pulley, a V-belt is held between a fixed pulley half and a movable pulley half slidable in the axial direction, and the effective radius thereof is varied by changing an axial position of the movable pulley half relative to the position of the fixed pulley half. In general, an iron made pulley is used for the V-belt automatic transmission. One example of such an iron made driven pulley will be shown in Fig. 14. Fig. 14 shows the rear portion of a power unit 01 in which an internal combustion engine is mounted at the front portion and a rear wheel is integrally, rotatably supported at the rear portion. In this rear portion of the power unit 01, an inner sleeve 06 is turnably supported on a reducer input shaft 03 of a reducer 02 having a rear axle 04 as an output shaft, and an outer sleeve 07 is slidably supported around the outer periphery of the inner sleeve 06. A driven pulley 08 is provided at the right ends of the inner sleeve 06 and the outer sleeve 07. The drive pulley 08 includes a fixed pulley half 09 fitted to the right end portion of the inner sleeve 06, and a movable pulley half 010 fitted to the right end portion of the outer sleeve 07. The right side fixed pulley half 09 is opposed to the left side movable pulley half 010, and a V-belt Oil is held therebetween. A clutch 012 is provided at left end portions of the reducer input shaft 03 and the sleeve 06, and the outer periphery of a drive plate 013 fitted to the left end portion" of the sleeve 06 is covered with a clutch outer 014 fitted to the left end portion of the reducer input shaft 03. A spring 015 is provided around the outer sleeve 07 in a state being interposed between the drive plate 013 and the movable pulley half 010, and the movable pulley half 010 is biased by the spring 015 toward the fixed pulley half 09 side so as to hold the V-belt Oil there between. A spring guide 016 on the movable pulley half 010 side and a spring guide 017 on the drive plate 013 side are provided between the outer periphery of the outer sleeve 07 and the inner periphery of the spring 015 in such a manner as to be partially overlapped to each other. In the case where the movable pulley half 010 is made of iron, it is required to be integrally fixed to the separate outer sleeve 07, to be provided with a lubricating oil introducing passage 018 for making smooth the sliding of the outer sleeve 07 against the inner sleeve 06, and to provided with an oil seal 019 for preventing leakage of a lubricating oil at each end of the outer sleeve 07. f 0008 ] As described above, the driven pulley 08 has a large number of parts and is complicated in structure. To cope with such an inconvenience, a driven pulley formed of aluminum by casting has been already proposed, for example, in Japanese Patent Laid-open No. Hei 4-224345. This example will be described with reference to Fig. 15. A fixed pulley half 021 of a driven pulley 020 in this example is formed of aluminum integrally with a cylindrical inner sleeve portion 02 la by die-cast, and it is turnably supported on a reducer input shaft 030. On the other hand, a movable pulley half 022 is also formed of aluminum integrally with an outer sleeve portion 022a by die-cast, and the outer sleeve portion 022a is slidably, rotatably supported around the outer periphery of the inner sleeve portion 02 la. A spring 025 is provided around the outer sleeve portion 022a in a state being interposed between a drive plate 026, of a clutch 027, fitted at the left end of the inner sleeve portion 021a and the movable pulley half 022, and the movable pulley half 022 is biased by the spring 025 toward the fixed pulley half 021 side so as to hold a V-belt 023 there between. In this way, the use of the driven pulley formed of aluminum by casting makes it possible to reduce the number of parts and simplify the structure, and hence to reduce the cost. As described above, a movable pulley half is generally biased by a spring to come close to a fixed pulley half, to increase an effective radius of a V-belt held there between, thereby imparting a tension to the V-belt. However, when such a load fluctuation as to exceed the biasing force of the spring is applied to the driven pulley, a slip is produced between the pulley and the V-belt. To prevent such a slip, there has been proposed a V-belt type automatic transmission including a torque cam mechanism for converting a rotation of a movable pulley half relative to a fixed pulley half into an axial thrust of the movable pulley half. An example described in Japanese Patent Laid-open c_._ No. Hei 4-224345 is shown in Figs. 15 and 16. Fig. 15 shows the rear portion of a power unit 01 in which an internal combustion engine is mounted at the front portion and a rear wheel is integrally, rotatably supported at the rear portion. In this rear portion of the power unit 01, a driven pulley 020 of a V-belt type automatic transmission is rotatably supported on a reducer input shaft 03 of a gear reducer 02 having a rear axle 04 as an output shaft. The drive plate 026 has cam contact projections 031 at three positions spaced at equal intervals, and a movable pulley half 022 has torque cams (movable side cam portions) 033 at three positions spaced at equal intervals. The torque cams 033 project opposite to the cam contact projections 031. As shown in Fig. 16, the cam contact projection 031 is obtained by forming parallel notches along inner and outer lines in the radial direction and raising the portion surrounded by the notches in a triangular shape. A sliding member (fixed side cam portion) 032 made of a synthetic resin is stuck on one inclined piece of the cam contact Projection 031, and the outer inclined surface of the sliding member 032 is taken as a sliding face 032a. On the other hand, the torque cam 033 has a cam face 033a inclined in accordance with the sliding face 032a of the sliding member 032. At the time of rapid acceleration generated, for example, upon starting of the vehicle, a relative rotation is generated between the fixed pulley half 021 applied with a load from the rear wheel and the movable pulley half not directly applied with the load, and accordingly the movable side torque cams 033 precede the fixed side cam contact projections 031 and the cam faces 033a are each brought in sliding-contact with the sliding faces 032a of the sliding members 032. As a result, the torque cams 033 are moved together with the movable pulley half 022 in the direction where they come close to the fixed pulley half 021, to thereby increase the holding force of the V-belt 023 and prevent the slip of the V-belt 023. [Problem to be Solved by the Invention] The torque cams 033 are not usually brought in contact with the sliding faces 032a of the sliding members 032, and when being apart therefrom, the torque cajns)o33 cannot prevent the slip of the V-belt 023 until they are brought in contact with the sliding faces 032a of the sliding members 032, which leads to the generation of an acceleration lag. In the example described in the above-described document, the torque cam 033 is configured to be brought in contact with the sliding member 032 which is provided on one inclined piece of the cam contact projection 031 positioned in front of the torque cam 033 in the rotational direction. In other words, any examination is not made of the contact of the torque cam 033 with the other inclined piece of the cam contact projection 031 positioned behind the torque cam 033 in the rotational direction, and consequently, as shown in Fig. 16, a clearance C allowing the torque cam 033 to move between the cam contact projections 031, 031 positioned in front of and behind the torque cam 033 becomes larger. In some cases, the torque cam 033 is apart, in a range of the clearance C, from the sliding member 032 positioned in front of the torque cam 033 in the rotational direction. In this case, if the distance of the torque cam 033 apart from the sliding member 032 is large, the acceleration lag becomes larger, with a result the driver cannot obtain a smooth acceleration feeling upon starting of the vehicle or the like. Furthermore, since the clearance C is large, there is a possibility that the torque cam 033 collides with the sliding face 032a of the sliding member 032 from a distant position or it is brought in contact with the other inclined piece, having no resin sliding portion, of the cam contact projection 031 positioned behind the torque cam 033, resulting in the reduced durability. Since the three torque cams 033 of the movable pulley half 022 are projectingly formed around the outer periphery of the outer sleeve portion 022a in such a manner as to be spaced from each other, there occurs a problem that the maintenance performance is poor. Additionally, since the resin made sliding member 032 produced separately is stuck on the cam contact projection 031 of the drive plate 026, there occurs a problem that the productivity is poor because of the increased number of production steps. In view of the foregoing, the present invention has been made, and a first object of the present invention is to provide a pulley structure of a V-belt type automatic transmission, which is capable of ensuring a preferable acceleration feeling by preventing the generation of an acceleration lag upon starting of the vehicle or the like and improving the maintenance performance and durability. In the related art pulley structure shown in Fig. 15, the spring 025 is made of spring steel, and one end thereof is brought in contact with the drive plate 026 integrated with the fixed pulley half 021 while the other end thereof is brought in contact with the movable pulley half 022 made of aluminum. The movable pulley half 022 is allowed to be slid in the axial direction and rotated in the peripheral direction relative to the fixed pulley half 021, that is, a relative turning motion is generated therebetween, and consequently the contact portion of the aluminum made movable pulley half 022 with the steel made spring 025 is liable to be worn by the sliding contact therebetween. Also, there is a possibility that the outer sleeve portion 022a of the movable pulley half 022 is worn by the friction between the spring 025 and the same. To prevent such a wear, it may be considered to increase a gap between the outer sleeve portion 022a and the spring 025; however, if the gap is increased without enlargement of the size of the pulley structure, the wall thickness of the outer sleeve portion 022a is thinned, resulting in the reduced strength thereof. Furthermore, it may be conspired to dispose such a spring guide as shown in the example of Fig. 14 between the outer sleeve portion 022a and the spring 025; however, in this case, there occurs a problem that the aluminum made outer sleeve portion 022a is liable to be worn by the friction between the steel made spring guide and the same. And, if a gap between the outer sleeve portion 022a and the spring guide without enlargement of the size of the pulley structure, the wall thickness of the outer sleeve portion 022a is thinned, resulting in the reduced strength thereof. In view of the foregoing, the present invention has been made, and a second object of the present invention is to provide a pulley structure of a V-belt type automatic transmission, which is reduced in weight, simplified and reduced in size while being kept in sufficient strength by the use of a movable pulley half made of aluminum. [Means for Solving the Problem, Function, and Effect] To achieve the first object of the present invention, there is provided a pulley structure of a V-belt type automatic transmission, the transnassion/a fixed pulley half rotatably supported on a rotational shaft; a movable pulley half disposed opposite to the fixed pulley half for holding a V-belt therebetween, the movable pulley"half being slidably, rotatably supported on a fixed pulley cylindrical shaft; and a torque cam mechanism for converting a turning motion of the movable pulley half relative to the fixed pulley half into an axial thrust of the movable pulley half; wherein the torque cam mechanism includes movable side cam portions and fixed side cam portions to be meshed with the movable side cam portions, the movable side cam portions being formed at an edge portion of a movable pulley cylindrical shaft of the movable pulley half in such a manner as to axially extend therefrom, the fixed cam portions being formed at an end portion of the fixed pulley cylindrical shaft in such a manner as to extend in the peripheral direction, and a clearance in the rotational direction between each of the movable pulley side cam portions and the corresponding one of the fixed pulley side cam portions is made small. Since the movable pulley side cam portions each mesh with the fixed pulley side cam portions and each clearance in the rotational direction therebetween is small, the movable pulley side cam portions are separated only slight amounts from the fixed pulley side cam portions positioned in front of the movable pulley side cam portions in the rotational direction, so that it is possible to shorten" a time lag until the torque cam mechanism acts at the time of generation of a rapid acceleration, for example, upon starting of the vehicle, and hence to usually ensure a smooth acceleration feeling substantially without the generation of an acceleration lag. Since each clearance in the rotational direction between the movable pulley side cam portions and the fixed pulley side cam portions is small, it is possible to prevent the generation of collision of the movable pulley side cam portion with the fixed pulley side cam portion from a distance position, and hence to improve the durability. Since the movable side cam portions are collectively formed on the edge portion of the cylindrical shaft of the movable pulley half in such a manner as to axially extend therefrom, it is possible to improve the maintenance performance. Since the movable pulley half including the movable pulley cylindrical shaft and the movable side cam portions is integrally formed of aluminum by casting, it is possible to reduce the number of parts and simplify the structure, and hence to improve the productivity, and further since each of the fixed side cam portions is formed of a resin member integrally molded on the core portion bent in cross-section, it is possible to further improve the productivity. Additionally, by provision of the fixed side cam portions on the drive plate, of the clutch, fixed to the end portion of the fixed pulley cylindrical shaft, it is possible to reduce the number of parts and hence to improve the productivity. To achieve the second object, according to the present invention, there is provided a pulley structure of a V-belt type automatic transmission, the transmission including: a fixed pulley half rotatably supported on a rotational shaft; and a movable pulley half disposed opposite to the fixed pulley half for holding a V-belt therebetween, the movable pulley half being slidably, rotatably supported on a fixed pulley cylindrical shaft, wherein the movable pulley half is formed of aluminum by casting or the like, a spring made of spring steel for biasing the movable pulley half toward the fixed pulley half side is provided in proximity to an outer periphery of the movable pulley cylindrical shaft, and a^ resin made spring guide is provided in a gap between an inner periphery of the spring and the outer periphery of the movable pulley cylindrical shaft. Since the movable pulley half including the movable pulley cylindrical shaft is formed of aluminum, it is possible to reduce the weight, to reduce the number of parts, and to simplify the pulley structure. Since the spring is provided in proximity to the outer periphery of the movable pulley cylindrical shaft and the resin made spring guide is provided in a gap between the inner periphery of the spring and the outer periphery of the movable pulley cylindrical shaft, even when the gap between the spring and the movable pulley cylindrical shaft is made small for reducing the size of the pulley structure, it is possible to prevent the generation of wear of the aluminum made movable pulley cylindrical shaft by the effect of the resin made spring guide, and hence to sufficiently keep the strength of the movable pulley cylindrical shaft. Furthermore, one end of the spring may be brought in contact with a flange formed at the end portion of the spring guide and the other end of the spring may be brought in contact with an iron made spring seat which is interposed between the movable pulley half and the same. In this case, since the end portion of the spring made of spring steel is brought in contact with the iron made spring seat, it is liable to slid on the spring seat, so that in the relative turning of the movable pulley half relative to the fixed pulley half, the sliding is liable to be generated between the steel made spring and the iron made spring seat, to prevent generation of any sliding at other portions, with a result that a preferable speed change characteristic can be usually obtained by preventing the generation of wear of the soft aluminum pulley and the resin made spring guide. Accordingly, the present invention relates to a pulley structure of a V-belt type automatic transmission device for a scooter type motorcycle, said transmission device comprising: a fixed pulley half rotatably supported on a rotational shaft; a movable pulley half disposed opposite to said fixed pulley half for holding a V-belt therebetween, said movable pulley half being slidably, rotatably supported on a fixed pulley cylindrical shaft; and a torque cam mechanism for converting a turning motion of said movable pulley half relative to said fixed pulley half into an axial thrust of said movable pulley half; characterised in that said torque cam mechanism has movable side cam portions and fixed side cam portions to be meshed with said movable side cam portions, said movable side cam portions being formed at an edge portion of a movable pulley cylindrical shaft of said movable pulley half so as to axially extend therefrom, said fixed cam portions are provided on a clutch drive plate fixed on the end portion of said fixed pulley cylindrical shaft and being formed at an end portion of said fixed pulley cylindrical shaft so as to extend in the peripheral direction, and a clearance in the rotational direction between each of said movable pulley side cam portions and the corresponding one of said fixed pulley side cam portions is made small. [Brief Description of the. Drawings] A side view showing the entire configuration of a scooter type motorcycle to which a V-belt type automatic transmission according to one embodiment of the present invention is applied. [Fig. 2] A sectional view taken on line II-II of Fig. 1, showing a power unit. [Fig. 3] A sectional view showing an essential portion of the rear side of the power unit shown in Fig. 2. [Fig. 4] A side view of a movable pulley half. [Fig. 5] A sectional view taken on line V-V of Fig. 4. [Fig. 6] A sectional view of a fixed pulley half. [Fig. 7] " A sectional view of a spring guide. [Fig. 8] A side view of a drive plate. [Fig. 9] A sectional view taken on line IX-IX of Fig. 8. [Fig. 10] A sectional view taken on line X-X of Fig. 8. [Fig. 11] A development showing an engagement state of fixed side cam portions with movable side cam portions. [Fig. 12] A graph showing a relationship between an engine speed and a vehicular speed. [Fig. 13] A development showing an engagement state of fixed side cam portions with movable side cam portions in another embodiment. [Fig. 14] A sectional view of a related art pulley structure, [Fig. 15] A sectional view of another related art pulley structure. [Fig. 16] A sectional view showing an essential portion of the pulley structure shown in Fig. 15. [Embodiment of the Invention] Hereinafter, one embodiment of the present invention will be described with reference to Figs. 1 to 13. Fig. 1 is a side view showing the entire configuration of a scooter type motorcycle 1 to which a V belt type automatic transmission of the present invention is applied. A front body 2 is connected to a rear body 3 via a floor portion 4 which is lower than the front and rear bodies"2 and 3. A body frame 5 descends from the front body 2, extending rearward in the horizontal direction along the floor portion 4, and rises from the rear end of the floor portion 4 and extends rearward, upward, obliquely to the rear end of the rear body 3. A front fork portion 8 is pivotably supported on the front portion of the body frame 5. A steering handlebar 6 is provided at the upper end of the front fork portion 5 and a front wheel 7 is rotatably supported at the lower end of the front fork portion 8. A lower, front end of a swing type power unit 20 is vertically rockably supported on a rising portion of the body frame 5 via a link 10. A rear wheel 9 is rotatably supported on the rear end of the power unit 20. A rear cushion 11 is interposed between a rear, upper surface of the power unit 20 and the body frame 5 over the rear, upper surface of the power unit 20. The front body 2 is covered with a leg shield; the floor portion 4 is provided with a step floor sheet 16; and the rear body 3 is covered with a body cover 17. A seat 18 is provided over the body cover 17. " The power unit 20 includes a single cylinder/two cycle type internal combustion engine 21 disposed at the front portion thereof, a gear reducer 22 provided at the rear portion thereof, and a V-belt type automatic transmission 23 disposed between the internal combustion engine 21 and the gear reducer 22. These components are unified and contained in a unit case 25. A structure of the power unit 20 is shown in Fig. 2. The unit case 25 includes a left case 26 longer in the longitudinal direction, a right case 27, a transmission case cover 28, and a gear case 29. The left case 26 contains the V-belt type automatic transmission 23 and the gear reducer 22, and it serves as a left half of a crank case of the internal combustion engine 21. The right case 27 is connected to a front portion of the left case 26 and it serves as a right half of the crank case. The transmission case cover 28 covers the left side of the left case 26, and the gear case 29 covers the gear reducer 22 from the left side. A crank shaft 31 is rotatably supported on the crank case composed of the left case 26 and the right case 27 by means of a pair of right and left main bearings 30, 30. A cylinder block 21a and a cylinder head 21b connected to each other are erected from the crank case of the internal combustion engine 21 in such a manner as to be inclined slightly rearward. A piston 32 slidably moved in the cylinder block 2la is connected to the crank shaft 31 via a connecting rod 33. An AC generator 34 and a cooling fan 35 are provided at the right end of the crank shaft 31, and the outer peripheries of the internal combustion engine 21, AC generator 34, and cooling fan 35 are covered with an engine cover 36. A drive pulley 40 of the V-belt type automatic transmission 23 is provided at the left end of the crank shaft 31. The drive pulley 40 includes a fixed pulley half 41 fixed at the left end of the crank shaft 31, and a movable pulley half 42 axially slidably supported on the crank shaft 31. In addition, the fixed pulley half 41 and the movable pulley half 42 are disposed opposite to each other. Centrifugal weights 44 are radially movably contained between the movable pulley half 42 and a lump plate 4"3 fixed on the crank shaft 31. The movable pulley half 42 comes close to the fixed pulley half 41 by movement of the centrifugal weights 44 in the centrifugal direction, to thereby increase an effective radius of a V-belt 55 held between both the pulleys 41, 42. The gear reducer 22 disposed in both the rear portion of the left case 26 and the gear case 29 has a speed reducing mechanism shown in Fig. 3, in which an intermediate shaft 46 is provided between the reducer input shaft 45 and a rear axle 47 as the reducer output shaft; a large diameter intermediate gear 49 fitted to the intermediate shaft 46 meshes with an input gear 48 fitted to the reducer input shaft 45; and an output gear 51 fitted to the rear axle 47 meshes with a small diameter intermediate gear 50 fitted to the intermediate shaft 46. As shown in Fig. 3, a driven pulley 60 and a clutch 70 are provided at the left half portion, passing through the gear case 29, of the reducer input shaft 45 of the gear reducer 22.• The driven pulley 60 includes a pair of a fixed pulley half 61 and a movable pulley half 62, which are disposed opposite to each other. Each of the pulley halves 61 and 62 is made of aluminum. As shown in Fig. 6, with respect to the fixed pulley half 61, an inner peripheral portion of the main body of the fixed pulley half 61 axially extends to form a cylindrical inner sleeve portion 6 la, and the end portion of the inner sleeve portion 6 la is slightly reduced in diameter to form a mounting portion 61b. The outer periphery of the mounting portion 61b is formed with serrations. The fixed pulley half 61 including the main body and the mounting portion 61b is integrally formed of aluminum by die-cast. As shown in Figs. 4 and 5, with respect to the movable pulley half 62, an inner peripheral portion of the main body of the movable pulley half 62 axially extends to form a cylindrical outer sleeve portion 62a having an inside diameter slightly larger than the outside diameter of the inner sleeve portion 61a of the fixed pulley half 61. Projections 62b, each having an arcuate shape in cross-section, are axially projectingly formed on the edge portion of the outer sleeve portion 62a at three positions spaced at equal intervals in the peripheral direction. The leading end of the projection 62b is bent clockwise in Fig. 4, to thus form a movable side cam portion 62c. The movable side cam portion 62c has an outer cam face 62co and an inner cam face 62ci, each of which is an inclined end surface extending in the peripheral direction. In this embodiment, the three movable side cam portions 62c are all provided with triangular swelled portions at the corners on the opposed side in the rotational direction to form the inner cam faces 62ci; however, such a swelled portion, that is, the inner cam face 62ci may be provided for only one movable side cam portion 62c because the inner cam face 62ci is intended to restrict the rotation relative to a fixed side cam portion 75 (which will be described later) and thereby it is not applied with a large load. In addition, an annular groove 62d is formed in an outer peripheral portion of the base of the outer sleeve portion 62a of the main body of the movable pulley half 62. The movable pulley half 62 including the main body and the movable side cam portion 62c is integrally formed of aluminum by die-cast. The driven pulley 60 having the above configuration is mounted as shown in Fig. 3. The fixed pulley half 61 is first mounted such that the inner sleeve portion 6 la is inserted around the reducer input shaft 45 and is rotatably supported thereon by means of a needle bearing 63 and a ball bearing 64, and the movable pulley half 62 is rotatably supported on the fixed pulley half 61 such that the outer sleeve portion 62a is slidably supported around the outer periphery of the inner sleeve portion 6 la of the fixed pulley half 61. The movable pulley half 62 is supported axially slidably and peripherally turnably relative to the fixed pulley half, and is positioned such that the main body thereof is opposed to that of the fixed pulley half 61. [ A clutch 70 is mounted to the left end of the reducer input shaft 45 and to the left end mounting portion 61b of the inner sleeve portion 6la of the fixed pulley half 61. The clutch 70 including a bottoming cylindrical, flat clutch outer 71 having a bottom wall 7la. The clutch outer 71 is fitted to the reducer input shaft 45 via a collar 73 by screwing a nut 74 passing through a center hole of the bottom wall 7la in a left end threaded portion of the reducer input shaft 45. The clutch outer 71 is opened” with a peripheral side wall 71b directed rightward. In the inside of the clutch outer 71, a drive plate 72 as a clutch inner is mounted by serration-fit with the left end mounting portion 61b of the inner sleeve portion 61a of the fixed pulley half 61. As shown in Figs. 8 to 10, the drive plate 72 has a cylindrical, flat serration fit portion 72a formed along the inner peripheral edge thereof, core portions 72b radially extending from the outer peripheral surface of the serration fit portion 72a, and an outer peripheral plate portion 72c slightly steppedly connected to the core portions 72b. Pins 73 are planted on the outer peripheral plate 72c at three positions spaced at equal intervals, and a clutch shoe 74 is rotatably supported on the pins 73. The core portions 72b, with which resin made fixed side cam portions 75 having a self-lubricating performance are each integrally molded, are provided at three positions spaced at equal intervals. Each space 72d is formed between the adjacent fixed side cam portions 75. The three movable side cam portions 62c of the movable pulley half 62 each face the three spaces 72d, and the resin made fixed side cam portions 75 each mesh with the movable side cam portions 62c. As shown in Fig. 10, the resin made fixed side cam portion 75 is fixed on the bent core portion 72b, and is formed in a substantially trapezoid shape. It has an inner cam face 75i which is an inclined flat end face extending in the peripheral direction, and an outer cam face 75o which is a curved face. The drive plate 72 having the above configuration is disposed in the clutch outer 71. The clutch shoe 74 rotatably supported on the pins 73 of the drive plate 72 are radially outward rocked against a clutch spring 76 by a centrifugal force, and a frictional member 74a provided on the outer periphery of the clutch shoe 74 is brought in contact with and engaged with the inner peripheral surface of the inner peripheral side wall 71b of the clutch outer 71. Since the drive plate 72 is integrally mounted by serration- fit on the left end mounting portion 61b of the inner sleeve portion 61a of the fixed pulley half 61, it is rotated integrally with the fixed pulley half 61. As shown in Fig. 3, with respect to the movable pulley half 62 slidably supported between the drive plate 72 and the main body of the fixed pulley half 61, a spring 80 made of spring steel is provided in proximity of the outer periphery of the outer sleeve portion 62a of the movable pulley half 62 while being interposed between the drive plate 72 and the movable pulley half 62 for biasing the movable pulley half 62 toward the fixed pulley half 61. A resin made spring guide 81 is interposed in a gap between the inner periphery of the spring 80 and the outer periphery of the outer sleeve portion 62a. As shown in Fig. 7 , the spring guide 81 is formed in a cylindrical shape, and has a flange 81a formed at one end thereof. The inside diameter of the spring guide 81 is slightly larger than the outside diameter of the outer sleeve portion 62a, and it is made slightly larger at the flange 81a side. When the spring guide 81 is disposed around the outer periphery of the outer sleeve portion 62a and the drive plate 72 is mounted on the left end mounting portion 61b of "the inner sleeve portion 61a, the resin made fixed side cam portions 75 are fitted in the enlarged inside diameter portion of the spring guide 81 and support the spring guide 81, and the flange 81a of the spring guide 81 is brought in contact with the stepped portion of the inner periphery of the outer peripheral plate portion 72c of the drive plate 72. On the other hand, a spring seat 82 formed of an annular iron plate is fitted in the annular groove 62d provided in the outer peripheral portion of the base of the outer sleeve portion 62a of the movable pulley half 62, and thus the spring 80 is interposed between the spring seat 82 and the flange 81a of the spring guide 81 with both the ends thereof being in contact therewith. In this way, the rear portion of the V-belt 55 with the front portion wound around the drive pulley 40 is held between the fixed pulley half 61 and the movable pulley half 62 biased by the spring 80, so that the movable pulley half 62 is biased by the spring 80 to come close to the fixed pulley half 61 side, to make larger the effective radius of the V-belt 55 wound therearound, thereby sufficiently stretching the V-belt 55. The movable side cam portions 62c at the left end of the outer sleeve portion 62a of the movable pulley half 62 face the spaces 72d of the drive plate 72 rotated integrally with the fixed pulley half 61 and mesh with the resin made fixed cam portions 75. The development of the engagement state between the three movable cam portions 62c and the three fixed side cam portions 75 is shown in Fig 11. Referring to Fig. 11, the inner cam face 75i and the outer cam face 75o of the fixed cam portion 75 respectively face the inner cam face 62ci and the outer cam face 62co of the movable side cam portion 62c. In this state, since a clearance C in the rotational direction is small, the facing cam faces can be easily brought in contact with each other. Accordingly, the rotational angle of the movable side cam portion 62c relative to the fixed side cam portion 75 can be restricted at a small value. The operation of the V-belt type automatic transmission having the above configuration according to the present invention will be described below. When the rotational speed of the internal combustion engine 21 is low, the power is transmitted in a state shown by the solid line in Fig. 2. On the drive pulley 40 side, the centrifugal weights 44 moved along the lump plate 43 are positioned on the center side and the movable pulley half 42 is separated from the fixed pulley half 41, to thereby make smaller the winding effective radius of the V-belt 55. At this time, on the driven pulley 60 side, the movably pulley half 62 is biased by the spring 80 to come close to the fixed pulley half 61, to thereby make larger the winding effective radius of the V-belt 55. As a result, in this state, the power is transmitted at a large reduction ratio. When the rotational speed of the engine is increased, the power is transmitted in a state shown by the two-dot chain line in Fig. 2. On the drive pulley 40 side, the centrifugal weights 44 are moved in the centrifugal direction and the movable pulley half 42 come close to the fixed pulley half 41, to thereby make larger the winding effective radius of the V-belt 55. At this time, on the driven pulley 60 side, the movable pulley half 62 is separated from the fixed pulley half 61 against the biasing force of the spring 80, to thereby make smaller the winding radius "of the V-belt 55. As a result, in this state, the reduction ratio is gradually decreased, and at the same time, since the clutch 70 is in an engagement state, the rotational speed of the rear wheel 9 is increased. In addition, when the rotational speed of the engine is increased, since the movable pulley half 62 is moved in the direction where it is separated from the fixed pulley half 61, the movable side cam portions 62c integrated with the movable pulley half 62 are inserted in the spaces 72d between the fixed side cam portions 75 as shown by the two-dot chain line in Fig. 11. The positions of the movable side cam portions 62c shown by the two-dot chain line in Fig. 11 show a TOP ratio state having such a small reduction ratio. In addition, the positions of the movable side cam portions 62c shown by the solid line in Fig. 11 show a LOW ratio state having the above-described large reduction ratio. When the tension of the V-belt 55 becomes rapidly stronger by rapid acceleration generated, for example, upon starting of the vehicle, a slip is produced between the V-belt 55 and the fixed pulley half 61 connected to the rear wheel 9 and applied with a large load while the load of the rear wheel 9 is not directly applied to the movable pulley half 62 rotatable relative to the fixed pulley half, so that the movable pulley half 62 is intended to be rotated * integrally with the V-belt 55. Accordingly, the movable pulley half 62 is rotated relative to the fixed pulley half 61, so that the movable side cam portions 62c integrated with the movable pulley half 62 are intended to be rotated relative to the fixed side cam portions 75 fixed on the drive plate 72 integrated with the fixed pulley half 61. Thus, as shown in Fig. 11, the movable side cam portions 62c are moved in the direction of the arrow A relative to the fixed side cam portions 75. At this time, the outer cam faces 62co of the movable side cam portions 62c are each brought in contact with the outer cam faces 75o of the fixed side cam portions 75 and thereby the movable side cam portions 62c receive reaction forces in the direction of the arrow B. Thus, the movable pulley half 62 comes close to the fixed pulley half 61, to increase a holding pressure of the V-belt, thereby preventing the slip of the V-belt 55. Since each fixed side cam portion 75 meshes with each movable side cam portion 62c with the small clearance C put therebetween, the outer cam face 62co of the movable side cam portion 62c is separated only a distance less than the clearance C from the outer cam face 75o of the fixed side cam portion 75. As a result, it is possible to shorten a time lag from the time when a slip is generated by rapid acceleration, for example, upon starting of the vehicle to the time when the slip is prevented by the contact of the cam faces 62co and 75o followed by the operation of the torque cam mechanism, and hence to substantially prevent the acceleration lag. This is effective to usually give a smooth acceleration feeling to the driver. Fig. 12 is a graph showing a relationship between an engine speed Ne and a vehicular speed V. As shown in this graph, when the clutch 70 is engaged at a certain engine speed n0 and a power is transmitted to the rear wheel 9, the vehicle is accelerated without a time lag after engagement of the clutch 70 by the effect of the torque cam mechanism as shown by the solid line. The case using the related art torque cam mechanism is shown by the broken line in Fig. 12, in which a slip time of the V-belt 55 is longer, that is, there is an acceleration lag after engagement of the clutch. Such a starting state of the vehicle is lacking in smooth acceleration feeling. The torque cam mechanism of V-belt type automatic transmission of the present invention has the following advantages. Since the clearance C between the fixed side cam portion 75 and the movable side cam portion 62c is small and further the inner and outer cam faces 75i, 75o of the resin made fixed side cam portion 72 are respectively brought in contact with the inner and outer cam faces 62ci, 62co of the movable side cam portion 62c, it is possible to reduce the wear and fatigue of the torque cam mechanism, and hence to increase the durability thereof. Since the three movable side cam portions 62c are collectively formed at the shaft end of the outer sleeve portion 62a, it is possible to improve the maintenance performance . Since in addition to the fixed pulley half 61, the movable pulley half 62 including the outer sleeve portion 62a and the movable side cam portions 62c are integrally formed of aluminum by die-cast, it is possible to reduce the number of parts and to simplify the structure, and hence to improve the productivity. Since the resin made fixed side cam portions 75 are molded integrally with the core portions 72b of the drive plate 72, it is possible to eliminate the work of preparing the cam portions separately and mounting them, and hence to further improve the productivity. As shown in Fig. 10, the core portion 72b of the drive plate 72 is branched into two parts for each fixed side cam portion 75, and it has a bent shape in cross-section, so that the resin made fixed side cam portion 75 molded integrally with the core portion 72b can be positively fixed thereto without no looseness. The fixing structure of the fixed side cam portion may be variously changed. For example, as shown in Fig. 13, a resin made fixed side cam portion 91 may be molded integrally with a core portion 90 of the drive plate formed in a shape complicatedly bent in cross-section. This is very effective to fix the fixed side cam portion 91 to the core portion 90 without any looseness. In addition, Fig. 13 is a development showing an engagement state between the fixed side cam portions 91 and movable side cam portions 92. The shapes of the cam portions 91, 92 are the same as those shown in the above- described embodiment. As described above, while not only the relative movement in the axial direction but also the relative rotation in the rotational direction are generated between the fixed pulley half 61 and the movable pulley half 62, the spring 80 provided in the proximity to the outer periphery of the outer sleeve portion 62a of the movable pulley half 62 is prevented from interfering the outer sleeve portion 62a by the resin made spring guide 81 put therebetween. In other words, the aluminum made outer sleeve portion 62a is prevented from being worn by the interference of the steel made spring 80. Since the spring 80 is guided by the outer periphery of the resin made spring guide 81, even when the spring guide 81 interferes the outer sleeve portion 62a, the amount of the wear of the outer sleeve portion 62a is very smaller than that caused by the interference of the steel fliade spring 80. Accordingly, the spring guide 81 is allowed to come close to the outer sleeve portion 62a, which is effective to reduce the wall thickness of the outer sleeve portion 62a, and hence to reduce the size of the pulley structure. Since each of the fixed pulley half 61 including the inner sleeve portion 6 la and the movable pulley half 62 including the outer sleeve portion 62a is formed of aluminum by die-cast, it is possible to reduce the number of parts and simplify the pulley structure, and hence to reduce the weight and the cost thereof. Additionally, since one end of the steel made spring 80 is brought in press-contact with the flange 81a of the resin made spring guide 81 while the other end thereof is brought in press-contact with the steel made spring seat 82 provided on the movable pulley half 62 side, the spring 80 is liable to be slid on the spring seat 82 and accordingly even when a relative rotation is generated between the fixed pulley half 61 and the movable pulley half 62, the spring 80 is mainly slid on the spring seat 82, so that there is no slip between the spring 80 and the resin made spring guide 81 and between the steel made spring'seat 82 and the aluminum made movable pulley half 62, to thereby extremely reduce the wear. The spring 80 thus usually acts in a normal state to keep the speed change characteristic of the V-belt type automatic transmission 23 at a desired state. [Reference Characters] 1: scooter type motorcycle, 2: front body, 3: rear body, 4: floor portion, 5: body frame, 6: steering handlebar, 7: front wheel, 8: front fork portion, 9: rear wheel, 10: link, 11: rear cushion, 15: leg shield, 16: step floor sheet, 17: body cover, 18: seat, 20: power unit, 21: internal combustion engine, 22: gear reducer, 23: V-belt type automatic transmission, 25: unit case, 26: left case, 27: right case, 28: transmission case cover, 29: gear case, 30: main bearing, 31: crank shaft, 32: piston, 33: connecting rod, 34: AC generator, 35: cooling fan, 36: engine cover, 40: drive pulley, 41: fixed pulley half, 42: movable pulley half, 43: lump plate, 44: centrifugal weight, 45: reducer input shaft, 46: intermediate shaft, 47: rear axle, 48: input gear, 49: intermediate gear, 50: intermediate gear, 51: output gear, 55: V-belt, 60: driven pulley, 61: fixed pulley half, 62: movable pulley half, 63: needle bearing, 64: ball bearing, 70: clutch, 71: clutch outer, 72: drive plate, 73: collar, 74: nut, 75: fixed side cam portion, 76: clutch spring, 80: spring, 81: spring guide, 82: spring seat, 90: core portion, 91: fixed side cam portion, 92: movable side cam portion WE CLAIM: 1. A pulley structure of a V-belt type automatic transmission device for a scooter type motorcycle, said transmission device comprising: a fixed pulley half rotatably supported on a rotational shaft; a movable pulley half disposed opposite to said fixed pulley half for holding a V-belt therebetween, said movable pulley half being slidably, rotatably supported on a fixed pulley cylindrical shaft; and a torque cam mechanism for converting a turning motion of said movable pulley half relative to said fixed pulley half into an axial thrust of said movable pulley half; characterised in that said torque cam mechanism has movable side cam portions and fixed side cam portions to be meshed with said movable side cam portions, said movable side cam portions being formed at an edge portion of a movable pulley cylindrical shaft of said movable pulley half so as to axially extend therefrom, said fixed cam portions are provided on a clutch drive plate fixed on the end portion of said fixed pulley cylindrical shaft and being formed at an end portion of said fixed pulley cylindrical shaft so as to extend in the peripheral direction, and a clearance in the rotational direction between each of said movable pulley side cam portions and the corresponding one of said fixed pulley side cam portions is made small. 2. A pulley structure of a V-belt type automatic transmission device as claimed in claim 1, wherein each of said movable side cam portions is integrally formed of aluminum by casting or the like, and each of said fixed side cam portions is formed of a resin member integrally molded on a core portion bent in cross-section. 3. A pulley structure of a V-belt type automatic transmission device as claimed in claim 1 , wherein said movable pulley half is formed of aluminum by casting or the like, a spring made of spring steel for biasing said movable pulley half toward said fixed pulley half side is provided in proximity to an outer periphery of said movable pulley cylindrical shaft, and a resin made spring guide is provided in a gap between an inner periphery of said spring and the outer periphery of said movable pulley cylindrical shaft. 4. A pulley structure of a V-belt type automatic transmission device as claimed in claim 4, wherein one end of said spring is brought in contact with a flange formed on an end portion of said spring guide, and the other end of said spring is brought in contact with a steel made spring seat which is provided on said movable pulley half. 5. A pulley structure of a V-belt type automatic transmission device for a scooter type motorcycle substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Full Text

The present invention relates to a pulley structure of a V-belt type automatic transmission device for a scooter type motorcycle and particularly to a torque cam mechanism and a pulley structure of the V-belt type automatic transmission.
A V-belt type automatic transmission includes a drive pulley, a driven pulley, and an endless belt which is V-shaped in cross-section and is wound between the drive pulley and the driven pulley, wherein a power is transmitted by automatically adjusting an effective radius of each pulley in accordance with an engine speed. In each pulley, a V-belt is held between a fixed pulley half and a movable pulley half slidable in the axial direction, and the effective radius thereof is varied by changing an axial position of the movable pulley half relative to the position of the fixed pulley half.
In general, an iron made pulley is used for the V-belt automatic transmission. One example of such an iron made driven pulley will be shown in Fig. 14.
Fig. 14 shows the rear portion of a power unit 01 in which an internal combustion engine is mounted at the front portion and a rear wheel is integrally, rotatably supported at the rear portion. In this rear portion of the power unit 01, an inner sleeve 06 is turnably supported on a reducer input shaft 03 of a reducer 02 having a rear axle 04 as an output shaft, and an outer sleeve 07 is slidably supported around the outer periphery of the inner sleeve 06.
A driven pulley 08 is provided at the right ends of the inner sleeve 06 and the outer sleeve 07. The drive pulley 08 includes a fixed pulley half 09 fitted to the right end portion of the inner sleeve 06, and a movable
pulley half 010 fitted to the right end portion of the outer sleeve 07. The right side fixed pulley half 09 is opposed to the left side movable pulley half 010, and a V-belt Oil is held therebetween.
A clutch 012 is provided at left end portions of the reducer input shaft 03 and the sleeve 06, and the outer periphery of a drive plate 013 fitted to the left end portion" of the sleeve 06 is covered with a clutch outer 014 fitted to the left end portion of the reducer input shaft 03.
A spring 015 is provided around the outer sleeve 07 in a state being interposed between the drive plate 013 and the movable pulley half 010, and the movable pulley half 010 is biased by the spring 015 toward the fixed pulley half 09 side so as to hold the V-belt Oil there between.
A spring guide 016 on the movable pulley half 010 side and a spring guide 017 on the drive plate 013 side are provided between the outer periphery of the outer sleeve 07 and the inner periphery of the spring 015 in such a manner as to be partially overlapped to each other.
In the case where the movable pulley half 010 is
made of iron, it is required to be integrally fixed to the separate outer sleeve 07, to be provided with a lubricating oil introducing passage 018 for making smooth the sliding of the outer sleeve 07 against the inner sleeve 06, and to provided with an oil seal 019 for preventing leakage of a lubricating oil at each end of the outer sleeve 07. f 0008 ]
As described above, the driven pulley 08 has a large number of parts and is complicated in structure. To cope with such an inconvenience, a driven pulley formed of aluminum by casting has been already proposed, for example, in Japanese Patent Laid-open No. Hei 4-224345. This example will be described with reference to Fig. 15.
A fixed pulley half 021 of a driven pulley 020 in this example is formed of aluminum integrally with a cylindrical inner sleeve portion 02 la by die-cast, and it is turnably supported on a reducer input shaft 030.
On the other hand, a movable pulley half 022 is also formed of aluminum integrally with an outer sleeve portion 022a by die-cast, and the outer sleeve portion 022a is slidably, rotatably supported around the outer periphery of the inner sleeve portion 02 la.
A spring 025 is provided around the outer sleeve portion 022a in a state being interposed between a drive plate 026, of a clutch 027, fitted at the left end of the inner sleeve portion 021a and the movable pulley half 022, and the movable pulley half 022 is biased by the spring 025 toward the fixed pulley half 021 side so as to hold a V-belt 023 there between.
In this way, the use of the driven pulley formed of aluminum by casting makes it possible to reduce the number of parts and simplify the structure, and hence to reduce the cost.
As described above, a movable pulley half is generally biased by a spring to come close to a fixed pulley half, to increase an effective radius of a V-belt held there between, thereby imparting a tension to the V-belt. However, when such a load fluctuation as to exceed the biasing force of the spring is applied to the driven pulley, a slip is produced between the pulley and the V-belt. To prevent such a slip, there has been proposed a V-belt type automatic transmission including a torque cam mechanism for converting a rotation of a movable pulley half relative to a fixed pulley half into an axial thrust of the movable pulley half.
An example described in Japanese Patent Laid-open
c_._ No. Hei 4-224345 is shown in Figs. 15 and 16.
Fig. 15 shows the rear portion of a power unit 01 in which an internal combustion engine is mounted at the front portion and a rear wheel is integrally, rotatably supported at the rear portion. In this rear portion of the power unit 01, a driven pulley 020 of a V-belt type automatic transmission is rotatably supported on a reducer input shaft 03 of a gear reducer 02 having a rear axle 04 as an output shaft.
The drive plate 026 has cam contact projections 031 at three positions spaced at equal intervals, and a movable pulley half 022 has torque cams (movable side cam portions) 033 at three positions spaced at equal intervals. The torque cams 033 project opposite to the cam contact projections 031.
As shown in Fig. 16, the cam contact projection 031 is obtained by forming parallel notches along inner and outer lines in the radial direction and raising the portion surrounded by the notches in a triangular shape. A sliding member (fixed side cam portion) 032 made of a synthetic resin is stuck on one inclined piece of the cam contact
Projection 031, and the outer inclined surface of the sliding member 032 is taken as a sliding face 032a.
On the other hand, the torque cam 033 has a cam face 033a inclined in accordance with the sliding face 032a of the sliding member 032.
At the time of rapid acceleration generated, for example, upon starting of the vehicle, a relative rotation is generated between the fixed pulley half 021 applied with a load from the rear wheel and the movable pulley half not directly applied with the load, and accordingly the movable side torque cams 033 precede the fixed side cam contact projections 031 and the cam faces 033a are each brought in sliding-contact with the sliding faces 032a of the sliding members 032. As a result, the torque cams 033 are moved together with the movable pulley half 022 in the direction where they come close to the fixed pulley half 021, to thereby increase the holding force of the V-belt 023 and prevent the slip of the V-belt 023.
[Problem to be Solved by the Invention]
The torque cams 033 are not usually brought in contact with the sliding faces 032a of the sliding members 032, and when being apart therefrom, the torque cajns)o33
cannot prevent the slip of the V-belt 023 until they are brought in contact with the sliding faces 032a of the sliding members 032, which leads to the generation of an acceleration lag.
In the example described in the above-described document, the torque cam 033 is configured to be brought in contact with the sliding member 032 which is provided on one inclined piece of the cam contact projection 031 positioned in front of the torque cam 033 in the rotational direction. In other words, any examination is not made of the contact of the torque cam 033 with the other inclined piece of the cam contact projection 031 positioned behind the torque cam 033 in the rotational direction, and consequently, as shown in Fig. 16, a clearance C allowing the torque cam 033 to move between the cam contact projections 031, 031 positioned in front of and behind the torque cam 033 becomes larger.
In some cases, the torque cam 033 is apart, in a range of the clearance C, from the sliding member 032 positioned in front of the torque cam 033 in the rotational direction. In this case, if the distance of the torque cam 033 apart from the sliding member 032 is large, the
acceleration lag becomes larger, with a result the driver cannot obtain a smooth acceleration feeling upon starting of the vehicle or the like.
Furthermore, since the clearance C is large, there is a possibility that the torque cam 033 collides with the sliding face 032a of the sliding member 032 from a distant position or it is brought in contact with the other inclined piece, having no resin sliding portion, of the cam contact projection 031 positioned behind the torque cam 033, resulting in the reduced durability.
Since the three torque cams 033 of the movable pulley half 022 are projectingly formed around the outer periphery of the outer sleeve portion 022a in such a manner as to be spaced from each other, there occurs a problem that the maintenance performance is poor.
Additionally, since the resin made sliding member 032 produced separately is stuck on the cam contact projection 031 of the drive plate 026, there occurs a problem that the productivity is poor because of the increased number of production steps.
In view of the foregoing, the present invention has been made, and a first object of the present invention is
to provide a pulley structure of a V-belt type automatic transmission, which is capable of ensuring a preferable acceleration feeling by preventing the generation of an acceleration lag upon starting of the vehicle or the like and improving the maintenance performance and durability. In the related art pulley structure shown in Fig. 15, the spring 025 is made of spring steel, and one end thereof is brought in contact with the drive plate 026 integrated with the fixed pulley half 021 while the other end thereof is brought in contact with the movable pulley half 022 made of aluminum.
The movable pulley half 022 is allowed to be slid in the axial direction and rotated in the peripheral direction relative to the fixed pulley half 021, that is, a relative turning motion is generated therebetween, and consequently the contact portion of the aluminum made movable pulley half 022 with the steel made spring 025 is liable to be worn by the sliding contact therebetween.

Also, there is a possibility that the outer sleeve portion 022a of the movable pulley half 022 is worn by the friction between the spring 025 and the same. To prevent such a wear, it may be considered to increase a gap between
the outer sleeve portion 022a and the spring 025; however, if the gap is increased without enlargement of the size of the pulley structure, the wall thickness of the outer sleeve portion 022a is thinned, resulting in the reduced strength thereof.
Furthermore, it may be conspired to dispose such a spring guide as shown in the example of Fig. 14 between the outer sleeve portion 022a and the spring 025; however, in this case, there occurs a problem that the aluminum made outer sleeve portion 022a is liable to be worn by the friction between the steel made spring guide and the same.
And, if a gap between the outer sleeve portion 022a and the spring guide without enlargement of the size of the pulley structure, the wall thickness of the outer sleeve portion 022a is thinned, resulting in the reduced strength thereof.
In view of the foregoing, the present invention has been made, and a second object of the present invention is to provide a pulley structure of a V-belt type automatic transmission, which is reduced in weight, simplified and reduced in size while being kept in sufficient strength by the use of a movable pulley half made of aluminum.
[Means for Solving the Problem, Function, and Effect]
To achieve the first object of the present
invention, there is provided a pulley structure of a V-belt

type automatic transmission, the transnassion/a fixed pulley half rotatably supported on a rotational shaft; a movable pulley half disposed opposite to the fixed pulley half for holding a V-belt therebetween, the movable pulley"half being slidably, rotatably supported on a fixed pulley cylindrical shaft; and a torque cam mechanism for converting a turning motion of the movable pulley half relative to the fixed pulley half into an axial thrust of the movable pulley half; wherein the torque cam mechanism includes movable side cam portions and fixed side cam portions to be meshed with the movable side cam portions, the movable side cam portions being formed at an edge portion of a movable pulley cylindrical shaft of the movable pulley half in such a manner as to axially extend therefrom, the fixed cam portions being formed at an end portion of the fixed pulley cylindrical shaft in such a manner as to extend in the peripheral direction, and a clearance in the rotational direction between each of the movable pulley side cam portions and the corresponding one of the fixed pulley side cam portions is made small.
Since the movable pulley side cam portions each mesh with the fixed pulley side cam portions and each clearance in the rotational direction therebetween is small, the movable pulley side cam portions are separated only slight amounts from the fixed pulley side cam portions positioned in front of the movable pulley side cam portions in the rotational direction, so that it is possible to shorten" a time lag until the torque cam mechanism acts at the time of generation of a rapid acceleration, for example, upon starting of the vehicle, and hence to usually ensure a smooth acceleration feeling substantially without the generation of an acceleration lag.
Since each clearance in the rotational direction between the movable pulley side cam portions and the fixed pulley side cam portions is small, it is possible to prevent the generation of collision of the movable pulley side cam portion with the fixed pulley side cam portion from a distance position, and hence to improve the durability.
Since the movable side cam portions are
collectively formed on the edge portion of the cylindrical shaft of the movable pulley half in such a manner as to
axially extend therefrom, it is possible to improve the
maintenance performance.
Since the movable pulley half including the movable pulley cylindrical shaft and the movable side cam portions is integrally formed of aluminum by casting, it is possible to reduce the number of parts and simplify the structure, and hence to improve the productivity, and further since each of the fixed side cam portions is formed of a resin member integrally molded on the core portion bent in cross-section, it is possible to further improve the productivity.
Additionally, by provision of the fixed side cam portions on the drive plate, of the clutch, fixed to the end portion of the fixed pulley cylindrical shaft, it is possible to reduce the number of parts and hence to improve the productivity.
To achieve the second object, according to the present invention, there is provided a pulley structure of a V-belt type automatic transmission, the transmission including: a fixed pulley half rotatably supported on a rotational shaft; and a movable pulley half disposed opposite to the fixed pulley half for holding a V-belt therebetween, the movable pulley half being slidably,
rotatably supported on a fixed pulley cylindrical shaft, wherein the movable pulley half is formed of aluminum by casting or the like, a spring made of spring steel for biasing the movable pulley half toward the fixed pulley half side is provided in proximity to an outer periphery of the movable pulley cylindrical shaft, and a^ resin made spring guide is provided in a gap between an inner periphery of the spring and the outer periphery of the movable pulley cylindrical shaft.
Since the movable pulley half including the movable pulley cylindrical shaft is formed of aluminum, it is possible to reduce the weight, to reduce the number of parts, and to simplify the pulley structure.
Since the spring is provided in proximity to the outer periphery of the movable pulley cylindrical shaft and the resin made spring guide is provided in a gap between the inner periphery of the spring and the outer periphery of the movable pulley cylindrical shaft, even when the gap between the spring and the movable pulley cylindrical shaft is made small for reducing the size of the pulley structure, it is possible to prevent the generation of wear of the aluminum made movable pulley cylindrical shaft by the effect of the resin made spring guide, and hence to
sufficiently keep the strength of the movable pulley
cylindrical shaft.
Furthermore, one end of the spring may be brought in contact with a flange formed at the end portion of the spring guide and the other end of the spring may be brought in contact with an iron made spring seat which is interposed between the movable pulley half and the same.
In this case, since the end portion of the spring made of spring steel is brought in contact with the iron made spring seat, it is liable to slid on the spring seat, so that in the relative turning of the movable pulley half relative to the fixed pulley half, the sliding is liable to be generated between the steel made spring and the iron made spring seat, to prevent generation of any sliding at other portions, with a result that a preferable speed change characteristic can be usually obtained by preventing the generation of wear of the soft aluminum pulley and the resin made spring guide.
Accordingly, the present invention relates to a pulley structure of a V-belt type automatic transmission device for a scooter type motorcycle, said transmission device comprising: a fixed pulley half rotatably supported on a rotational shaft; a movable pulley half disposed opposite to said fixed pulley half for holding a V-belt therebetween, said movable pulley half being slidably, rotatably supported on a fixed pulley cylindrical shaft; and a torque cam mechanism for converting a turning motion of said movable pulley half relative to said fixed pulley half into an axial thrust of said movable pulley half; characterised in that said torque cam mechanism has movable side cam portions and fixed side cam portions to be meshed with said movable side cam portions, said movable side cam portions being formed at an edge portion of a movable pulley cylindrical shaft of said movable pulley half so as to axially extend therefrom, said fixed cam portions are provided on a clutch drive plate fixed on the end portion of said fixed pulley cylindrical shaft and being formed at an end portion of said fixed pulley cylindrical shaft so as to extend in the peripheral direction, and a clearance in the rotational direction between each of said movable pulley side cam portions and the corresponding one of said fixed pulley side cam portions is made small.
[Brief Description of the. Drawings]
A side view showing the entire configuration of a scooter type motorcycle to which a V-belt type automatic transmission according to one embodiment of the present invention is applied. [Fig. 2]
A sectional view taken on line II-II of Fig. 1, showing a power unit. [Fig. 3]
A sectional view showing an essential portion of
the rear side of the power unit shown in Fig. 2. [Fig. 4]
A side view of a movable pulley half. [Fig. 5]
A sectional view taken on line V-V of Fig. 4. [Fig. 6]
A sectional view of a fixed pulley half. [Fig. 7]
" A sectional view of a spring guide. [Fig. 8]
A side view of a drive plate. [Fig. 9]
A sectional view taken on line IX-IX of Fig. 8. [Fig. 10]
A sectional view taken on line X-X of Fig. 8. [Fig. 11]
A development showing an engagement state of fixed side cam portions with movable side cam portions. [Fig. 12]
A graph showing a relationship between an engine speed and a vehicular speed. [Fig. 13]
A development showing an engagement state of fixed side cam portions with movable side cam portions in another
embodiment. [Fig. 14]
A sectional view of a related art pulley structure, [Fig. 15]
A sectional view of another related art pulley structure. [Fig. 16]
A sectional view showing an essential portion of the pulley structure shown in Fig. 15.
[Embodiment of the Invention]
Hereinafter, one embodiment of the present invention will be described with reference to Figs. 1 to
13.
Fig. 1 is a side view showing the entire configuration of a scooter type motorcycle 1 to which a V belt type automatic transmission of the present invention is applied.
A front body 2 is connected to a rear body 3 via a floor portion 4 which is lower than the front and rear bodies"2 and 3. A body frame 5 descends from the front body 2, extending rearward in the horizontal direction along the floor portion 4, and rises from the rear end of the floor portion 4 and extends rearward, upward, obliquely to the rear end of the rear body 3.
A front fork portion 8 is pivotably supported on the front portion of the body frame 5. A steering handlebar 6 is provided at the upper end of the front fork portion 5 and a front wheel 7 is rotatably supported at the lower end of the front fork portion 8.
A lower, front end of a swing type power unit 20 is vertically rockably supported on a rising portion of the body frame 5 via a link 10. A rear wheel 9 is rotatably supported on the rear end of the power unit 20. A rear cushion 11 is interposed between a rear, upper surface of
the power unit 20 and the body frame 5 over the rear, upper surface of the power unit 20.
The front body 2 is covered with a leg shield; the floor portion 4 is provided with a step floor sheet 16; and the rear body 3 is covered with a body cover 17. A seat 18 is provided over the body cover 17.
" The power unit 20 includes a single cylinder/two cycle type internal combustion engine 21 disposed at the front portion thereof, a gear reducer 22 provided at the rear portion thereof, and a V-belt type automatic transmission 23 disposed between the internal combustion engine 21 and the gear reducer 22. These components are unified and contained in a unit case 25.
A structure of the power unit 20 is shown in Fig. 2.
The unit case 25 includes a left case 26 longer in the longitudinal direction, a right case 27, a transmission case cover 28, and a gear case 29. The left case 26 contains the V-belt type automatic transmission 23 and the gear reducer 22, and it serves as a left half of a crank case of the internal combustion engine 21. The right case
27 is connected to a front portion of the left case 26 and it serves as a right half of the crank case. The transmission case cover 28 covers the left side of the left case 26, and the gear case 29 covers the gear reducer 22 from the left side.
A crank shaft 31 is rotatably supported on the crank case composed of the left case 26 and the right case 27 by means of a pair of right and left main bearings 30, 30. A cylinder block 21a and a cylinder head 21b connected to each other are erected from the crank case of the internal combustion engine 21 in such a manner as to be inclined slightly rearward.
A piston 32 slidably moved in the cylinder block 2la is connected to the crank shaft 31 via a connecting rod 33.
An AC generator 34 and a cooling fan 35 are provided at the right end of the crank shaft 31, and the outer peripheries of the internal combustion engine 21, AC generator 34, and cooling fan 35 are covered with an engine cover 36.
A drive pulley 40 of the V-belt type automatic
transmission 23 is provided at the left end of the crank shaft 31. The drive pulley 40 includes a fixed pulley half 41 fixed at the left end of the crank shaft 31, and a movable pulley half 42 axially slidably supported on the crank shaft 31. In addition, the fixed pulley half 41 and the movable pulley half 42 are disposed opposite to each other. Centrifugal weights 44 are radially movably contained between the movable pulley half 42 and a lump plate 4"3 fixed on the crank shaft 31.
The movable pulley half 42 comes close to the fixed pulley half 41 by movement of the centrifugal weights 44 in the centrifugal direction, to thereby increase an effective radius of a V-belt 55 held between both the pulleys 41, 42.
The gear reducer 22 disposed in both the rear portion of the left case 26 and the gear case 29 has a speed reducing mechanism shown in Fig. 3, in which an intermediate shaft 46 is provided between the reducer input shaft 45 and a rear axle 47 as the reducer output shaft; a large diameter intermediate gear 49 fitted to the intermediate shaft 46 meshes with an input gear 48 fitted to the reducer input shaft 45; and an output gear 51 fitted to the rear axle 47 meshes with a small diameter
intermediate gear 50 fitted to the intermediate shaft 46.
As shown in Fig. 3, a driven pulley 60 and a clutch 70 are provided at the left half portion, passing through the gear case 29, of the reducer input shaft 45 of the gear
reducer 22.•
The driven pulley 60 includes a pair of a fixed pulley half 61 and a movable pulley half 62, which are disposed opposite to each other. Each of the pulley halves 61 and 62 is made of aluminum.
As shown in Fig. 6, with respect to the fixed pulley half 61, an inner peripheral portion of the main body of the fixed pulley half 61 axially extends to form a cylindrical inner sleeve portion 6 la, and the end portion of the inner sleeve portion 6 la is slightly reduced in diameter to form a mounting portion 61b. The outer periphery of the mounting portion 61b is formed with serrations. The fixed pulley half 61 including the main body and the mounting portion 61b is integrally formed of aluminum by die-cast.
As shown in Figs. 4 and 5, with respect to the movable pulley half 62, an inner peripheral portion of the
main body of the movable pulley half 62 axially extends to form a cylindrical outer sleeve portion 62a having an inside diameter slightly larger than the outside diameter of the inner sleeve portion 61a of the fixed pulley half 61. Projections 62b, each having an arcuate shape in cross-section, are axially projectingly formed on the edge portion of the outer sleeve portion 62a at three positions spaced at equal intervals in the peripheral direction. The leading end of the projection 62b is bent clockwise in Fig. 4, to thus form a movable side cam portion 62c.
The movable side cam portion 62c has an outer cam face 62co and an inner cam face 62ci, each of which is an inclined end surface extending in the peripheral direction.
In this embodiment, the three movable side cam portions 62c are all provided with triangular swelled portions at the corners on the opposed side in the rotational direction to form the inner cam faces 62ci; however, such a swelled portion, that is, the inner cam face 62ci may be provided for only one movable side cam portion 62c because the inner cam face 62ci is intended to restrict the rotation relative to a fixed side cam portion 75 (which will be described later) and thereby it is not applied with a large load.
In addition, an annular groove 62d is formed in an outer peripheral portion of the base of the outer sleeve portion 62a of the main body of the movable pulley half 62.
The movable pulley half 62 including the main body and the movable side cam portion 62c is integrally formed of aluminum by die-cast.
The driven pulley 60 having the above configuration is mounted as shown in Fig. 3. The fixed pulley half 61 is first mounted such that the inner sleeve portion 6 la is inserted around the reducer input shaft 45 and is rotatably supported thereon by means of a needle bearing 63 and a ball bearing 64, and the movable pulley half 62 is rotatably supported on the fixed pulley half 61 such that the outer sleeve portion 62a is slidably supported around the outer periphery of the inner sleeve portion 6 la of the fixed pulley half 61.
The movable pulley half 62 is supported axially slidably and peripherally turnably relative to the fixed pulley half, and is positioned such that the main body thereof is opposed to that of the fixed pulley half 61. [
A clutch 70 is mounted to the left end of the reducer input shaft 45 and to the left end mounting portion
61b of the inner sleeve portion 6la of the fixed pulley half 61.
The clutch 70 including a bottoming cylindrical, flat clutch outer 71 having a bottom wall 7la. The clutch outer 71 is fitted to the reducer input shaft 45 via a collar 73 by screwing a nut 74 passing through a center hole of the bottom wall 7la in a left end threaded portion of the reducer input shaft 45. The clutch outer 71 is opened” with a peripheral side wall 71b directed rightward.
In the inside of the clutch outer 71, a drive plate 72 as a clutch inner is mounted by serration-fit with the left end mounting portion 61b of the inner sleeve portion 61a of the fixed pulley half 61.
As shown in Figs. 8 to 10, the drive plate 72 has a cylindrical, flat serration fit portion 72a formed along the inner peripheral edge thereof, core portions 72b radially extending from the outer peripheral surface of the serration fit portion 72a, and an outer peripheral plate portion 72c slightly steppedly connected to the core portions 72b.
Pins 73 are planted on the outer peripheral plate
72c at three positions spaced at equal intervals, and a clutch shoe 74 is rotatably supported on the pins 73.
The core portions 72b, with which resin made fixed side cam portions 75 having a self-lubricating performance are each integrally molded, are provided at three positions spaced at equal intervals.
Each space 72d is formed between the adjacent fixed side cam portions 75. The three movable side cam portions 62c of the movable pulley half 62 each face the three spaces 72d, and the resin made fixed side cam portions 75 each mesh with the movable side cam portions 62c.
As shown in Fig. 10, the resin made fixed side cam portion 75 is fixed on the bent core portion 72b, and is formed in a substantially trapezoid shape. It has an inner cam face 75i which is an inclined flat end face extending in the peripheral direction, and an outer cam face 75o which is a curved face.
The drive plate 72 having the above configuration is disposed in the clutch outer 71. The clutch shoe 74 rotatably supported on the pins 73 of the drive plate 72 are radially outward rocked against a clutch spring 76 by a centrifugal force, and a frictional member 74a provided on
the outer periphery of the clutch shoe 74 is brought in contact with and engaged with the inner peripheral surface of the inner peripheral side wall 71b of the clutch outer 71.
Since the drive plate 72 is integrally mounted by serration- fit on the left end mounting portion 61b of the inner sleeve portion 61a of the fixed pulley half 61, it is rotated integrally with the fixed pulley half 61.
As shown in Fig. 3, with respect to the movable pulley half 62 slidably supported between the drive plate 72 and the main body of the fixed pulley half 61, a spring 80 made of spring steel is provided in proximity of the outer periphery of the outer sleeve portion 62a of the movable pulley half 62 while being interposed between the drive plate 72 and the movable pulley half 62 for biasing the movable pulley half 62 toward the fixed pulley half 61.
A resin made spring guide 81 is interposed in a gap between the inner periphery of the spring 80 and the outer periphery of the outer sleeve portion 62a.
As shown in Fig. 7 , the spring guide 81 is formed in a cylindrical shape, and has a flange 81a formed at one
end thereof. The inside diameter of the spring guide 81 is slightly larger than the outside diameter of the outer sleeve portion 62a, and it is made slightly larger at the flange 81a side.
When the spring guide 81 is disposed around the outer periphery of the outer sleeve portion 62a and the drive plate 72 is mounted on the left end mounting portion 61b of "the inner sleeve portion 61a, the resin made fixed side cam portions 75 are fitted in the enlarged inside diameter portion of the spring guide 81 and support the spring guide 81, and the flange 81a of the spring guide 81 is brought in contact with the stepped portion of the inner periphery of the outer peripheral plate portion 72c of the drive plate 72.
On the other hand, a spring seat 82 formed of an annular iron plate is fitted in the annular groove 62d provided in the outer peripheral portion of the base of the outer sleeve portion 62a of the movable pulley half 62, and thus the spring 80 is interposed between the spring seat 82 and the flange 81a of the spring guide 81 with both the ends thereof being in contact therewith.
In this way, the rear portion of the V-belt 55 with the front portion wound around the drive pulley 40 is held between the fixed pulley half 61 and the movable pulley half 62 biased by the spring 80, so that the movable pulley half 62 is biased by the spring 80 to come close to the fixed pulley half 61 side, to make larger the effective radius of the V-belt 55 wound therearound, thereby sufficiently stretching the V-belt 55.
The movable side cam portions 62c at the left end of the outer sleeve portion 62a of the movable pulley half 62 face the spaces 72d of the drive plate 72 rotated integrally with the fixed pulley half 61 and mesh with the resin made fixed cam portions 75. The development of the engagement state between the three movable cam portions 62c and the three fixed side cam portions 75 is shown in Fig 11.
Referring to Fig. 11, the inner cam face 75i and the outer cam face 75o of the fixed cam portion 75 respectively face the inner cam face 62ci and the outer cam face 62co of the movable side cam portion 62c. In this state, since a clearance C in the rotational direction is small, the facing cam faces can be easily brought in
contact with each other.
Accordingly, the rotational angle of the movable side cam portion 62c relative to the fixed side cam portion 75 can be restricted at a small value.
The operation of the V-belt type automatic transmission having the above configuration according to the present invention will be described below.
When the rotational speed of the internal combustion engine 21 is low, the power is transmitted in a state shown by the solid line in Fig. 2. On the drive pulley 40 side, the centrifugal weights 44 moved along the lump plate 43 are positioned on the center side and the movable pulley half 42 is separated from the fixed pulley half 41, to thereby make smaller the winding effective radius of the V-belt 55. At this time, on the driven pulley 60 side, the movably pulley half 62 is biased by the spring 80 to come close to the fixed pulley half 61, to thereby make larger the winding effective radius of the V-belt 55. As a result, in this state, the power is transmitted at a large reduction ratio.
When the rotational speed of the engine is increased, the power is transmitted in a state shown by the
two-dot chain line in Fig. 2. On the drive pulley 40 side, the centrifugal weights 44 are moved in the centrifugal direction and the movable pulley half 42 come close to the fixed pulley half 41, to thereby make larger the winding effective radius of the V-belt 55. At this time, on the driven pulley 60 side, the movable pulley half 62 is separated from the fixed pulley half 61 against the biasing force of the spring 80, to thereby make smaller the winding radius "of the V-belt 55. As a result, in this state, the reduction ratio is gradually decreased, and at the same time, since the clutch 70 is in an engagement state, the rotational speed of the rear wheel 9 is increased.
In addition, when the rotational speed of the engine is increased, since the movable pulley half 62 is moved in the direction where it is separated from the fixed pulley half 61, the movable side cam portions 62c integrated with the movable pulley half 62 are inserted in the spaces 72d between the fixed side cam portions 75 as shown by the two-dot chain line in Fig. 11.
The positions of the movable side cam portions 62c shown by the two-dot chain line in Fig. 11 show a TOP ratio state having such a small reduction ratio.
In addition, the positions of the movable side cam
portions 62c shown by the solid line in Fig. 11 show a LOW ratio state having the above-described large reduction ratio.
When the tension of the V-belt 55 becomes rapidly stronger by rapid acceleration generated, for example, upon starting of the vehicle, a slip is produced between the V-belt 55 and the fixed pulley half 61 connected to the rear wheel 9 and applied with a large load while the load of the rear wheel 9 is not directly applied to the movable pulley half 62 rotatable relative to the fixed pulley half, so that the movable pulley half 62 is intended to be rotated
*
integrally with the V-belt 55.
Accordingly, the movable pulley half 62 is rotated relative to the fixed pulley half 61, so that the movable side cam portions 62c integrated with the movable pulley half 62 are intended to be rotated relative to the fixed side cam portions 75 fixed on the drive plate 72 integrated with the fixed pulley half 61. Thus, as shown in Fig. 11, the movable side cam portions 62c are moved in the direction of the arrow A relative to the fixed side cam portions 75.

At this time, the outer cam faces 62co of the movable side cam portions 62c are each brought in contact with the outer cam faces 75o of the fixed side cam portions 75 and thereby the movable side cam portions 62c receive reaction forces in the direction of the arrow B. Thus, the movable pulley half 62 comes close to the fixed pulley half 61, to increase a holding pressure of the V-belt, thereby preventing the slip of the V-belt 55.
Since each fixed side cam portion 75 meshes with each movable side cam portion 62c with the small clearance C put therebetween, the outer cam face 62co of the movable side cam portion 62c is separated only a distance less than the clearance C from the outer cam face 75o of the fixed side cam portion 75. As a result, it is possible to shorten a time lag from the time when a slip is generated by rapid acceleration, for example, upon starting of the vehicle to the time when the slip is prevented by the contact of the cam faces 62co and 75o followed by the operation of the torque cam mechanism, and hence to substantially prevent the acceleration lag. This is effective to usually give a smooth acceleration feeling to the driver.
Fig. 12 is a graph showing a relationship between an engine speed Ne and a vehicular speed V. As shown in this graph, when the clutch 70 is engaged at a certain engine speed n0 and a power is transmitted to the rear wheel 9, the vehicle is accelerated without a time lag after engagement of the clutch 70 by the effect of the torque cam mechanism as shown by the solid line.
The case using the related art torque cam mechanism is shown by the broken line in Fig. 12, in which a slip time of the V-belt 55 is longer, that is, there is an acceleration lag after engagement of the clutch. Such a starting state of the vehicle is lacking in smooth acceleration feeling.
The torque cam mechanism of V-belt type automatic transmission of the present invention has the following advantages.
Since the clearance C between the fixed side cam portion 75 and the movable side cam portion 62c is small and further the inner and outer cam faces 75i, 75o of the resin made fixed side cam portion 72 are respectively brought in contact with the inner and outer cam faces 62ci, 62co of the movable side cam portion 62c, it is possible to reduce the wear and fatigue of the torque cam mechanism,
and hence to increase the durability thereof.
Since the three movable side cam portions 62c are collectively formed at the shaft end of the outer sleeve portion 62a, it is possible to improve the maintenance performance .
Since in addition to the fixed pulley half 61, the movable pulley half 62 including the outer sleeve portion 62a and the movable side cam portions 62c are integrally formed of aluminum by die-cast, it is possible to reduce the number of parts and to simplify the structure, and hence to improve the productivity.
Since the resin made fixed side cam portions 75 are molded integrally with the core portions 72b of the drive plate 72, it is possible to eliminate the work of preparing the cam portions separately and mounting them, and hence to further improve the productivity.
As shown in Fig. 10, the core portion 72b of the drive plate 72 is branched into two parts for each fixed side cam portion 75, and it has a bent shape in cross-section, so that the resin made fixed side cam portion 75 molded integrally with the core portion 72b can be
positively fixed thereto without no looseness.
The fixing structure of the fixed side cam portion may be variously changed. For example, as shown in Fig. 13, a resin made fixed side cam portion 91 may be molded integrally with a core portion 90 of the drive plate formed in a shape complicatedly bent in cross-section. This is very effective to fix the fixed side cam portion 91 to the core portion 90 without any looseness.
In addition, Fig. 13 is a development showing an engagement state between the fixed side cam portions 91 and movable side cam portions 92. The shapes of the cam portions 91, 92 are the same as those shown in the above-
described embodiment.
As described above, while not only the relative movement in the axial direction but also the relative rotation in the rotational direction are generated between the fixed pulley half 61 and the movable pulley half 62, the spring 80 provided in the proximity to the outer periphery of the outer sleeve portion 62a of the movable pulley half 62 is prevented from interfering the outer sleeve portion 62a by the resin made spring guide 81 put therebetween. In other words, the aluminum made outer
sleeve portion 62a is prevented from being worn by the interference of the steel made spring 80.
Since the spring 80 is guided by the outer periphery of the resin made spring guide 81, even when the spring guide 81 interferes the outer sleeve portion 62a, the amount of the wear of the outer sleeve portion 62a is very smaller than that caused by the interference of the steel fliade spring 80.
Accordingly, the spring guide 81 is allowed to come close to the outer sleeve portion 62a, which is effective to reduce the wall thickness of the outer sleeve portion 62a, and hence to reduce the size of the pulley structure.
Since each of the fixed pulley half 61 including the inner sleeve portion 6 la and the movable pulley half 62 including the outer sleeve portion 62a is formed of aluminum by die-cast, it is possible to reduce the number of parts and simplify the pulley structure, and hence to reduce the weight and the cost thereof.
Additionally, since one end of the steel made spring 80 is brought in press-contact with the flange 81a of the resin made spring guide 81 while the other end
thereof is brought in press-contact with the steel made spring seat 82 provided on the movable pulley half 62 side, the spring 80 is liable to be slid on the spring seat 82 and accordingly even when a relative rotation is generated between the fixed pulley half 61 and the movable pulley half 62, the spring 80 is mainly slid on the spring seat 82, so that there is no slip between the spring 80 and the resin made spring guide 81 and between the steel made spring'seat 82 and the aluminum made movable pulley half 62, to thereby extremely reduce the wear.
The spring 80 thus usually acts in a normal state to keep the speed change characteristic of the V-belt type automatic transmission 23 at a desired state.
[Reference Characters]
1: scooter type motorcycle, 2: front body, 3: rear body, 4: floor portion, 5: body frame, 6: steering handlebar, 7: front wheel, 8: front fork portion, 9: rear wheel, 10: link, 11: rear cushion, 15: leg shield, 16: step floor sheet, 17: body cover, 18: seat, 20: power unit, 21: internal combustion engine, 22: gear reducer, 23: V-belt type automatic transmission, 25: unit case, 26: left case, 27: right case, 28: transmission case cover, 29: gear case, 30: main bearing, 31: crank shaft, 32: piston, 33: connecting rod, 34: AC generator, 35: cooling fan, 36: engine cover, 40: drive pulley, 41: fixed pulley half, 42: movable pulley half, 43: lump plate, 44: centrifugal weight, 45: reducer input shaft, 46: intermediate shaft, 47: rear axle, 48: input gear,
49: intermediate gear, 50: intermediate gear, 51: output gear, 55: V-belt, 60: driven pulley, 61: fixed pulley half, 62: movable pulley half, 63: needle bearing, 64: ball bearing, 70: clutch, 71: clutch outer, 72: drive plate, 73: collar, 74: nut, 75: fixed side cam portion, 76: clutch spring, 80: spring, 81: spring guide, 82: spring seat, 90: core portion, 91: fixed side cam portion, 92: movable side cam portion

WE CLAIM:
1. A pulley structure of a V-belt type automatic transmission device for a
scooter type motorcycle, said transmission device comprising:
a fixed pulley half rotatably supported on a rotational shaft;
a movable pulley half disposed opposite to said fixed pulley half for holding a V-belt therebetween, said movable pulley half being slidably, rotatably supported on a fixed pulley cylindrical shaft; and
a torque cam mechanism for converting a turning motion of said movable pulley half relative to said fixed pulley half into an axial thrust of said movable pulley half;
characterised in that said torque cam mechanism has movable side cam portions and fixed side cam portions to be meshed with said movable side cam portions, said movable side cam portions being formed at an edge portion of a movable pulley cylindrical shaft of said movable pulley half so as to axially extend therefrom, said fixed cam portions are provided on a clutch drive plate fixed on the end portion of said fixed pulley cylindrical shaft and being formed at an end portion of said fixed pulley cylindrical shaft so as to extend in the peripheral direction, and a clearance in the rotational direction between each of said movable pulley side cam portions and the corresponding one of said fixed pulley side cam portions is made small.
2. A pulley structure of a V-belt type automatic transmission device as
claimed in claim 1, wherein each of said movable side cam portions is
integrally formed of aluminum by casting or the like, and each of said fixed
side cam portions is formed of a resin member integrally molded on a core portion bent in cross-section.
3. A pulley structure of a V-belt type automatic transmission device as
claimed in claim 1 , wherein said movable pulley half is formed of aluminum
by casting or the like, a spring made of spring steel for biasing said movable
pulley half toward said fixed pulley half side is provided in proximity to an
outer periphery of said movable pulley cylindrical shaft, and a resin made
spring guide is provided in a gap between an inner periphery of said spring
and the outer periphery of said movable pulley cylindrical shaft.
4. A pulley structure of a V-belt type automatic transmission device as
claimed in claim 4, wherein one end of said spring is brought in contact with
a flange formed on an end portion of said spring guide, and the other end of
said spring is brought in contact with a steel made spring seat which is
provided on said movable pulley half.
5. A pulley structure of a V-belt type automatic transmission device for a
scooter type motorcycle substantially as hereinbefore described with
reference to and as illustrated in the accompanying drawings.

Documents:

1021-del-1997-abstract.pdf

1021-del-1997-claims.pdf

1021-del-1997-correspondence-others.pdf

1021-del-1997-correspondence-po.pdf

1021-del-1997-description (complete).pdf

1021-del-1997-drawings.pdf

1021-del-1997-form-1.pdf

1021-del-1997-form-13.pdf

1021-del-1997-form-19.pdf

1021-del-1997-form-2.pdf

1021-del-1997-form-3.pdf

1021-del-1997-form-4.pdf

1021-del-1997-form-6.pdf

1021-del-1997-gpa.pdf

1021-del-1997-petition-137.pdf

1021-del-1997-petition-138.pdf

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Patent Number

214887

Indian Patent Application Number

1021/DEL/1997

PG Journal Number

10/2008

Publication Date

07-Mar-2008

Grant Date

18-Feb-2008

Date of Filing

21-Apr-1997

Name of Patentee

HONDA GIKEN KODYO KABUSHIKI KAISHA

Applicant Address

1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN,

Inventors:

#	Inventor's Name	Inventor's Address
1	SHINJI KUGA	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAISHA, JAPAN.
2	ISAMU TAKAHASHI	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAISHA, JAPAN.

PCT International Classification Number

F16H 9/12

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	HEI-18-101187	1996-04-23	Japan
2	HEI-8-101186	1996-04-23	Japan