Title of Invention	V-BELT TYPE CONTINUOUSLY VARIABLE TRANSMISSION
Abstract	A V-belt type continuously variable transmission comprising a thread-feeing mechanism includes an axially stationary side thread assembly and an axially movable side thread assembly. The axially stationary side thread assembly is provided with an axially stationary side thread portion, held to be able to rotate relatively, while being inhibited from rotating axially relative to the rotating shaft, and is drivingly rotated by an electric motor via a reduction gear mechanism. The axially movable side thread assembly is provided with an axially movable side thread portion fitted to the axially stationary side thread portion and is held movably in the axial direction of the rotating shaft while being inhibited from rotating relative to a transmission case. The axially movable side thread assembly of the thread-feeding mechanism is attached to the pulley movable half so as to be unable to move axially, relatively to each other and be able to rotate relatively to each other.

Title of Invention

V-BELT TYPE CONTINUOUSLY VARIABLE TRANSMISSION

Abstract

A V-belt type continuously variable transmission comprising a thread-feeing mechanism includes an axially stationary side thread assembly and an axially movable side thread assembly. The axially stationary side thread assembly is provided with an axially stationary side thread portion, held to be able to rotate relatively, while being inhibited from rotating axially relative to the rotating shaft, and is drivingly rotated by an electric motor via a reduction gear mechanism. The axially movable side thread assembly is provided with an axially movable side thread portion fitted to the axially stationary side thread portion and is held movably in the axial direction of the rotating shaft while being inhibited from rotating relative to a transmission case. The axially movable side thread assembly of the thread-feeding mechanism is attached to the pulley movable half so as to be unable to move axially, relatively to each other and be able to rotate relatively to each other.

Full Text	[Name of Document] Specification [Title of the Invention] V-belt Type Continuously Variable Transmission [Technical Field] The present invention relates generally to a V-belt type continuously variable transmission and, in particular, to a mechanism for driving its pulley movable half and a variable gear ratio mechanism for the transmission. [Background Art] In a V-belt type continuously variable transmission, a pulley stationary half is fastened to a rotating shaft while a pulley movable half is attached to the rotating shaft so as to be unable to rotate relatively to each other and able to move in the axial direction. The thread feeding mechanism in the driving mechanism of a pulley movable half included in the conventional V-belt type continuously variable transmission is configured as below. An axially stationary side thread portion is held on a rotating shaft via a bearing and attached to a transmission case so as to be unable to rotate and move in the axial direction. An axially movable side thread portion is in meshing engagement with the outer circumferential thread of the above-mentioned axially stationary side thread portion. This axially movable side thread portion is attached to the pulley movable half via a bearing so as to be able to rotate relatively to each other and unable to move in the axial direction. In addition, a motor drivingly rotates it through a reduction gear mechanism. When the motor is started up, the axially movable side thread portion moves axially, while rotating, to move the pulley movable half in the axial direction (for example, refer to Patent Document 1). With the above-mentioned configuration, the axially movable side thread portion in meshing engagement, via a gear integral therewith, with the final gear of the reduction gear mechanism moves in itself in the axial direction while drivingly rotated. Therefore, it is necessary that the final gear of the reduction gear mechanism be in itself elongated in the axial direction, which causes the transmission mechanism to grow in size. Also, a known example of the conventional techniques is that a distance between the stationary half and movable half of a driving pulley is controlled by a speed change actuator provided with an electric motor, while a distance between the stationary half and movable half of a driven pulley is set through a gear mechanism in conjunction with the driving pulley (e.g., refer to Patent Document 2). This example provides a complicate interlocking mechanism. [Patent Document 1] Patent No. 3099023 (Fig. 5) [Patent Document 2] Japanese Patent Laid-open No. 2001-330093 (Fig. 6) [Disclosure of the Invention] [Problems to be solved by the Invention] A destination of the present invention is to provide a V-belt type continuously variable transmission capable of being reduced in size by improving the driving mechanism of a pulley movable half. Another destination of the present invention is to simplify the structure of a variable gear ratio mechanism by providing a speed change actuator driven by an electric motor for each of a driving pulley and a driven pulley, instead of the conjunction of the driving pulley with the driven pulley through the conventional complicate gear mechanism. [Means for solving the Problems] The present invention has solved the above-mentioned problem and the invention recited in claim 1 is a V-belt type continuously variable transmission comprising: a pulley stationary half which is fixedly supported on a rotating shaft; a pulley movable half which is supported on the rotating shaft so as to face the pulley stationary-half and be movable axially while being inhibited from rotating relative to the rotating shaft, the pulley movable half in cooperation with the pulley stationary half gripping a belt therebetween; and a thread-feeing mechanism including: an axially stationary side thread assembly which is provided with an axially stationary side thread portion, held to be able to rotate relatively, while being inhibited from moving axially relative to the rotating shaft, and is drivingly rotated by an electric motor via a reduction gear mechanism; and an axially movable side thread assembly which is provided with an axially movable side thread portion fitted to the axially stationary side thread portion and is held movably in the axial direction of the rotating shaft while being inhibited from rotating relative to a transmission case; wherein the axially movable side thread assembly of the thread-feeding mechanism is attached to the pulley movable half so as to be unable to move axially, relatively to each other and be able to rotate relatively to each other. The invention recited in claim 2 is, in the V-belt type continuously variable transmission recited in claim 1, the axially movable side thread portion is supported on the pulley movable half through a bearing member so as to be able to rotate relatively to each other and unable to move axially, relatively to each other; and that the axially movable side thread portion and the bearing member are provided inside the axially stationary side thread portion. The invention recited in claim 3 is, in the V-belt type continuously variable transmission recited in claim 1, one of reduction gears is disposed in a gap defined between an input gear of the axially stationary side thread assembly included in the thread-feeding mechanism and an umbrella portion of the pulley movable half. The present invention has solved the above-mentioned problem and the invention recited in claim 4 is the V-belt type continuously variable transmission recited in claim 1, further including: a driving pulley including the stationary half and the movable half; a driven pulley including the stationary half and the movable half; and a speed change actuator provided for each of the driving pulley and the driven pulley; wherein the speed change actuator includes a feeding mechanism which engages with the movable half of each of the driving pulley and the driven pulley and an electric motor which drives the feeding mechanism, and the driving pulley and the driven pulley are controlled independently of each other. The invention recited in claim 5 is wherein, in the V-belt type continuously variable transmission recited in claim 4, the feeding mechanism for the driven pulley is disposed opposite to a clutch member across the stationary half and movable half of the driven pulley. The invention recited in claim 6 is wherein, in the V-belt type continuously variable transmission recited in claim 4 or 5, at least one of the two feeding mechanisms includes a thrust force adjusting mechanism. The invention recited in claim 7 is wherein, in the V-belt type continuously variable transmission recited in claim 4, the thrust force adjusting mechanism includes a spring. The invention recited in claim 8 is wherein, in the V-belt type continuously variable transmission recited in claim 4, the thrust force adjusting mechanism includes a spring and a stroke sensor for detecting extension and contraction of the spring, and both the pulleys are controlled on the basis of a detected value of the stroke sensor. [Effects of the Invention] In the invention of claim 1, the input gear of the thread-feeding mechanism meshing with and driven by the final gear of the reduction gear mechanism is a gear of the axially stationary thread assembly, which does not move in the axial direction. Therefore, the final gear of the reduction gear mechanism can be reduced in width, so that the transmission can be downsized. According to the invention of claim 2, the axially movable side thread portion and the bearing member are disposed by using the inside part in the width portion of the axially stationary thread portion. Therefore, the transmission can be downsized by effectively utilizing the dead space. According to the invention of claim 3, one of the reduction gears is disposed by effectively utilizing the dead space defined between the input gear of the axially stationary side thread assembly and the umbrella portion of the pulley movable half. Therefore, the transmission can be downsized. According to the invention of claim 4, a space adapted for arrangement of the feeding mechanism can be secured with ease. In addition, the cooling performance of the electric motor can be ensured. According to the invention of claim 5, a space located on the outer surface side of each of both umbrella portions, of the driven pulley, confronting each other can be utilized effectively. According to the invention of claim 6, it is possible to adjust the lateral pressure of the V-belt, which can improve durability of the belt. According to the invention of claim 7, the thrust force can be adjusted by a simple structure including the spring, which makes it easy to optimize the lateral pressure of the belt at any time. According to the invention of claim 8, it is possible to easily exercise pulley-control in accordance with an adjustment amount of belt-lateral pressure. [Best Mode for Carrying out the Invention] Fig. 1 is a side view of a power unit 1 according to the present invention. This power unit is mounted on a motorcycle and includes an overhead 4-stroke cycle 2-cylinder water-cooled internal combustion engine 2 fixed to a vehicle, a transmission 3, a rear wheel support portion 4 and a rear wheel, which are composed of in an integral manner. The transmission 3 is supported by the engine 2 so as to vertically swing around a crankshaft 11. Arrow F denotes the front of the internal combustion engine 2. The engine 2 of the power unit 1 includes a crankcase 6, a cylinder block 7, a cylinder head 8, a cylinder head cover 9 and a portion surrounded by such components. The cylinder block 7 facing forward and slightly upward is joined to the front end of the crankcase 6. The cylinder head 8 is joined to the front end of the cylinder block 7. The cylinder head cover 9 is joined to the front end of the cylinder head 8. A rear wheel shaft 60 is built in the rear wheel support portion 4 to transmit power from the engine to the rear wheel. Fig. 2 is a cross-sectional development view depicting A-A section, B-B section and C-C section of Fig. 1 on a plane. The crankcase 6 is composed of a left crankcase 6L and a right crankcase 6R. The crankshaft 11 is carried for rotation by the respective journal bearings 10L and 10R of the left and right crankcases 6L and 6R. On the other hand, cylinder bores 12 are formed in the cylinder block 7 and respective pistons 13 are slidably fitted into the cylinder bores 12. A connecting rod 16 has two ends, one of which is pivotally supported by the crankshaft 11 via a crank pin 14 and the other of which is pivotally supported by the piston 13 via a piston pin 15. Reciprocation of the pistons 13 rotates the crankshaft 11. A combustion chamber 20 is defined on the bottom face of the cylinder head 8 facing the end face of the piston 13. An ignition plug 21 is attached from the top of the cylinder head cover 9 in such a manner that the leading end of the ignition plug 21 faces the combustion chamber 20. The cylinder head 8 is formed with an intake port and an exhaust port contiguous to the combustion engine 20. An intake valve and an exhaust valve are slidably fitted into the cylinder head 8. The intake valve opens/closes the opening of an intake port on the combustion chamber side and the exhaust valve opens/closes the opening of an exhaust port on the combustion chamber side. Fig. 2 depicts an exhaust valve 27 of a right combustion chamber. In Fig. 2, a camshaft 28 is carried between the cylinder head 8 and the cylinder head cover 9 in parallel to the crankshaft 11. The intake valves and exhaust valves are drivingly opened and closed by cams formed on the camshaft 28. Fig. 2 depicts an exhaust cam 29. An endless chain 32 wound between a driving sprocket 30 and a driven sprocket 31 drivingly rotates the camshaft 28. The driving sprocket 30 is provided on the right-hand portion of the crankshaft 11 and the driven sprocket 31 on the right-hand portion of the camshaft 28. A right crankcase cover 33 is provided on the outside of the right crankcase 6R. A generator 36 is made up of a stator 34 fixed to the inner surface of the right crankcase cover 33 and a rotor 35. fixed to the crankshaft 11 to surround the stator 34. A driven gear 37 provided adjacently to the generator 36 is adapted to receive a rotary-driving force from a starter motor not shown. A transmission case 38 is adapted to house therein the transmission 3 of the power unit 1. The transmission case 38 is composed of a right transmission case 38R, a left transmission case 38L and a partition wall 38S. The right transmission case 38R is movably supported on the left-hand and right-hand sides of the crankcase 6. On the left-hand side of the crankcase, as shown in Fig. 5, the right transmission case 38R is movably supported by a ball bearing 40. A support metal 39 attached to the left crankcase 6L with a bolt 22 holds the ball bearing 40. On the right-hand side of the crankcase, the right transmission case 38R is movably supported by connection metals 43A, 43B held by a roller bearing 42. A support metal 41 attached to the right crankcase cover 33 holds the roller bearing 42. The connection metals 43A, 43B are joined together with a bolt. A transmission case cover 23 is provided on the outside of the left transmission case 38L. The left transmission case 38L and the partition wall 38S are each joined to the right transmission case 38R with bolts. The rear end portion of the transmission case 38 for the transmission 3 serves as the rear wheel support portion 4. The transmission 3 is composed of a V-belt type continuously variable transmission 45 and a mechanical reduction gear unit 46. The continuously variable transmission 45 is provided such that its front half is disposed between the left transmission case 3 8L and the right transmission case 38R and its rear half is disposed between the left transmission case 38L and the partition wall 38S. In addition, the reduction gear unit 46 is disposed between the partition wall 38S and the right transmission case 38R. The driving shaft of the continuously variable transmission 45 is the crankshaft 11. A driving pulley 47 of the continuously variable transmission 45 is attached to the left end of the crankshaft 11. The driving pulley 47 is composed of a stationary half 48 and a movable half 49. A driven shaft 50 of the continuously variable transmission 45 is carried for rotation by the left transmission case 38L, the partition wall 38 and the right transmission case 38R. A driven pulley 52 of the continuously variable transmission 45 is attached to the driven shaft 50 through a centrifugal clutch 51. The driven pulley 52 is composed of a stationary half 53 and a movable half 54. An endless V-belt 55 is spanned between the driving pulley 47 and the driven pulley 52 so as to transmit rotation of the driving pulley 47 to the driven pulley 52. When the rotating speed of the driven pulley 52 exceeds a predetermined rotating speed, the centrifugal clutch 51 disposed between the driven pulley 52 and the driven shaft 50 comes into an engagement state, where the driven shaft 50 starts to rotate. The reduction gear unit 46 is composed of gear groups carried on three rotating shafts. A first shaft is a right half portion of the driven shaft 50 of the transmission 45 carried by the right transmission case 38R and the partition wall 38S. The first shaft is formed with a reduced diameter gear 56 thereon. A second shaft is an intermediate shaft 57 carried for rotation by the right transmission case 38R and the partition wall 38S. The intermediate shaft 57 has an enlarged diameter gear 58 fitted integrally thereto, which meshes with the reduced diameter gear 56 of the driven shaft 50. In addition, the intermediate shaft 57 is formed with a reduced diameter gear 59 adjacent to the enlarged diameter gear 58. A third shaft is the rear wheel shaft 60 carried for rotation by the partition wall 38S, the right transmission case 38R and an arm 62 which is joined to the connection metal 43A. The rear wheel shaft 60 has an enlarged diameter gear 62 fitted to thereto, which meshes with the reduced diameter gear 59 of the intermediate shaft 57. With this configuration, torque of the driven shaft 50 is reduced via the above-mentioned reduction gear group and transmitted to the rear wheel shaft 60. The rear wheel 5 is integrally fastened to the rear wheel shaft 60. Fig. 3 is an enlarged cross-sectional view depicting a state of the driving pulley 47 and its periphery members assembled to the crack shaft 11. The driving pulley 47 is composed of the driving pulley stationary half 48 and the driving pulley movable pulley 49. The crankshaft 11 is formed at the left half portion thereof with a first reduced diameter portion 11A and a second reduced diameter portion 11B. The first reduced diameter portion 11A is defined between steps1 1a, 11b and the second reduced diameter portion 11B is defined between the step 11b and a crankshaft end face 11e. The first reduced diameter portion 11A is formed with a spline 11d at its end portion and the second reduced diameter portion 11B is formed with a spline 11e at its end portion. The inner race of a ball bearing 63, a first support sleeve 64 and a guide sleeve 65 are fitted onto the first reduced diameter portion 11A. A second support sleeve 66 and the driving pulley stationary half 48 are fitted onto the second reduced diameter portion 11B. The sleeves 64, 65, 66 are made of steel and the driving pulley stationary half 48 is made of aluminum. The components mentioned above are fastened via a washer 67 with a bolt 6 8 that is screwed into a thread hole formed in the end of the crankshaft 11 and are secured so as to be unable to move in the direction of the crankshaft 11. Of the components mentioned above, the guide sleeve 65 is fitted onto the spline 11d of the first reduced diameter portion 11A via a spline 65a disposed inside the spline 11d. The driving pulley stationary half 48 is provided with a central hole and a spline 48a formed inside the central hole, and is fitted onto the spline 11e of the second reduced diameter portion 11B via the spline 48a. Thus, the components mentioned above are secured so as to be unable to move relative to the crankshaft 11. The driving pulley stationary half 48 is rotated together with the crankshaft 11. The driving pulley movable half 49 is composed of an umbrella portion 49A confronting the stationary half, and a cylindrical portion 49B which is formed integrally with the umbrella portion 49A so as to surround the sleeves 64, 65, 66 mentioned above. The umbrella portion 49A is made of an aluminum alloy and the cylindrical portion 49B is made of steel. The umbrella portion 49A is joined integrally to the flange portion of the cylindrical portion with rivets 44. The cylindrical portion 49B of the driving pulley movable half 49 is formed on the inside thereof with a projecting spline 49Ba projecting inward. The projecting spline 49Ba is fitted onto an outside spline 65b formed on the outer circumference of the guide sleeve 6 5. Since the outside spline 65b of the guide sleeve 65 extends in an axial direction, the projecting spline 4 9Ba is slidable in the axial direction in the guide groove thereof. Thus, while being unable to rotate relative to the crankshaft 11, the driving pulley movable half 49 is held movably in the axial direction. With the splines 11d, 65a, 65b, 49Ba, the driving pulley movable half 4 9 receives torque from the crankshaft 11 and rotates together with the crankshaft 11. Grease is applied to the groove of the outside spline 65b included in the guide sleeve 65, which allows the projecting spline 49Ba of the cylindrical portion 49B to slide smoothly. The movable half cylindrical portion 49B is provided at both ends thereof with seals 69 for preventing leak of the grease and entering of dust. Fig. 4 is an enlarged cross-sectional view of only a shaft portion (i.e., excluding the ball bearings, etc.) taken along line IV-IV of Fig. 3. The spline11d of the crankshaft 11 and the inner spline 6 5a of the guide sleeve 65 which are in meshing engagement with each other are each an involute spline. In addition, also the outer spline 65b of the guide sleeve 65 and the projecting spline 49Ba meshing therewith are each an involute spline. In order to enable air and grease to move along with movement of the projecting spline, clearances 70 are defined between the outer circumferential surface of the guide sleeve and the inner circumferential surface of the movable half cylindrical portion 49B. In Fig. 3, a ball bearing outer race holding member 75 formed in a cylindrical shape holds the outer race of the ball bearing 63 attached to the crankshaft 11 so as to be unable to move relatively thereto in the axial direction. An internal thread cylindrical member 76 is integrally joined to an outer circumferential flange 75a of the ball bearing outer race-hoiding member 75 by welding. An annular gear 77 is joined to an outer circumferential flange 7 6a of the internal thread cylindrical member 76 with bolts 78. The ball bearing outer race holding member 75, the internal thread cylindrical member 76 and the annular gear 77 are united to constitute an internal thread assembly 79. The crankshaft 11 with the ball bearing 63 carries this internal thread assembly 79 so that it can be rotated independently of the crankshaft 11 while being unable to move in the axial direction. The annular gear 77 of the internal thread assembly 79 is drivingly rotated by a reduced diameter gear 102 of a second intermediate gear 104 serving as part of a speed change actuator 90 described later. The inner race of the ball bearing 72 is attached to the outer circumference of the cylindrical portion 49B included in the driving pulley movable half 49 so as to be unable to move in the axial direction. An external thread cylindrical member 80, specifically, its internal circumference, integrally holds the outer race of the ball bearing 72. The external circumferential threaded portion of the external thread cylindrical member 80 is in meshing engagement with the internal circumferential thread portion of the internal thread cylindrical member. A locking member 81 is fastened, with bolts 82, to a flange 80a formed at an end of the external thread cylindrical member 80. The external thread cylindrical member 80, the locking member 81 and the bolts 82 are united to constitute an external thread assembly 83. The locking member 81 has a locking shaft portion 81, and projecting portions 81b formed to project from both sides of the locking shaft portion 81a. The projecting portions 81b engage respective locking guide rails 84 provided on the right transmission case 38R shown in Fig. 6 (side view) . Thus, when the internal thread assembly 7 9 is rotating, the external thread assembly 83 can move only in the axial direction of the crankshaft while inhibited from rotating about the crankshaft. The internal thread assembly 79 and the external thread assembly 83 constitute a thread-feeding mechanism 89. A front stopper 81c is integrally formed on the arm portion of the locking member 81 in order to detect the limit of rearward displacement of the external thread assembly 83. A rear stopper 85 is attached, with a bolt 86, to the rear end of the shaft portion 81a included in the locking member 81 in order to detect the limit of forward displacement of the external thread assembly 83. The locking member 81 and the locking guide rails 84 (Fig. 6) constitute a locking mechanism 88 (Fig. 6). The locking member 81 includes an extension 81d formed externally of the shaft portion thereof. This extension 81d is in contact with the tip of a rod projecting from an end of a stroke sensor 87, which is used to detect the current position of the movable half. Stroke detection is made by detecting displacement of the rod that is pushed out of the end of the stroke sensor 87 by a spring. Rubber bellows surrounds the rod. The proximal portion of the stroke sensor 87 is connected to the right transmission case 38R. Fig. 5 is a cross-sectional development view of the front half of the transmission 3. Fig. 6 is an arrangement plan of gears, etc. showing the front half of the transmission as viewed from the side. The speed change actuator 90 drivingly rotates the internal thread assembly 79. This actuator 9 0 is composed of an electric motor 91 and a reduction gear mechanism 92. The electric motor 91 is automatically controlled in rotation in accordance with vehicle speed, throttle opening, and internal combustion engine speed. A reduction gear case 93 is fastened to the right transmission case 38R. This reduction gear case 93 is composed of a right case member 93R, a left case member 93L and an end case member 93E, which define a reduction gear chamber 94 therebetween. The electric motor 91 is attached to the right case member 93R of the reduction gear case 93 via an attachment plate 95. A pinion 96 formed on the rotating shaft of the motor extends into the reduction gear chamber 94. An enlarged diameter gear 97 meshing with the pinion 9 6 and a reduced diameter gear 98 adjacent thereto are integrally formed to constitute a first intermediate gear 99. The first intermediate gear 99 is supported for rotation by the reduction gear case 93 via ball bearings 100. An enlarged diameter gear 101 meshing with the reduced diameter gear 98 and a reduced diameter gear 102 adjacent integrally thereto which are fitted onto a rotating shaft 103 integrally constitute a second intermediate gear 104. The second intermediate gear 104 is supported for rotation by the reduction gear case 93 via ball bearings 105. The above-mentioned reduced diameter gear 102 is in meshing engagement with the annular gear 77 of the internal thread assembly 79 described earlier. When the electric motor 91 rotates in a normal direction in response to a control instruction, power is transmitted via the first and second intermediate gears 99, 104 to the internal thread assembly 79 to rotate. The threaded portion of the external cylindrical member 80 of the external thread assembly unable to rotate is in meshing engagement with the threaded portion of the internal thread cylindrical member 76. This threaded portion of the external thread assembly 80 receives a thrust force exerted in the axial direction of the crankshaft from the threaded portion of the internal thread cylindrical member 76. Thus, the external thread assembly 83 is moved in the axial direction of the crankshaft. The thrust force received by the threaded portion of the external cylindrical member 80 is transmitted via the ball bearings 72 to the driving pulley movable half 49 to move it in the axial direction of the crankshaft. This movement reduces the distance between the movable half 4 9 and the driving pulley stationary half 48 to thereby displace the V-belt in an outer circumferential direction. When the electric motor 91 is rotated in the reverse direction in response to a control instruction, according to the process reverse to that described above, the distance between the driving pulley stationary half 48 and the driving pulley movable half 49 is increased to thereby displace the V-belt toward the center. Fig. 7 is a cross-sectional development view of the rear half of the transmission 3. The driven pulley 52 is composed of the driven pulley stationary half 53 and the driven pulley movable half 54. The stationary half 53 is composed of an umbrella portion 53A made of aluminum and a cylindrical portion 53B made of steel. The driven pulley movable half 54 is also composed of an umbrella portion 54A made of aluminum and a cylindrical portion 54B made of steel. The umbrella portion of the stationary half 53 is fastened to the end of the cylindrical portion with bolts 147. The umbrella portion of the movable half 54 is integrally joined to the end of the cylindrical portion by casting. The driven shaft 50 is formed with stepped portions 50a, 50b, and 50c. A ball bearing 110 is provided on the outer circumference of the driven shaft so as to be adjacent to the stepped portion 50a and a roller bearing 111 is provided on the outer circumference of the driven shaft so as to be adjacent to the stepped portion 50b. The cylindrical portion 53B of the stationary half 53 is supported by the ball bearing 110 and the roller bearing 111 for rotation relative to the driven shaft 50. The cylindrical portion 54B of the movable half is fitted slidably to the outer circumference of the cylindrical portion 53B of the stationary half. Pins 112 are erectly provided at four points in the outer circumference of the cylindrical portion 53B of the stationary half. The cylindrical portion 54B of the movable half is formed with cam grooves 113, at four locations of the circumferential direction, each of which passes through the cylindrical portion 54B in the radial direction thereof and extends to slant with respect to the axial direction. The heads of the pins 112 are each fitted into a corresponding one of the cam grooves 113. Thus, the driven pulley movable half 54, while being restricted by the pins 112, can move toward the driven pulley stationary half 53 in the axial direction relatively to each other and in the circumferential direction of the cam grooves relatively to each other according to the angle of the cam grooves. The cylindrical member 114 is secured to the outer circumference of the cylindrical portion 54B of the driven pulley movable half 54 so as to be unable to move in the axial direction for covering the cam grooves 113 of the cylindrical portion. Grease is applied in the cam groove 113 to assist the slide of the driven pulley movable half that is restricted by the pins 112. In addition, seals are provided inside both ends of the cylindrical member 114 so as to prevent oil from leaking therefrom. The inner race of the ball bearing 115 is held on the outer circumference of the right end of the cylindrical member 114. An annular member 116 is brought into contact with the outer race of the ball bearing 115. The inner race of a ball bearing 117 is fastened, with a nut 118, to a stepped portion that is provided on the outer circumference, and at the left end, of the cylindrical portion 53B of the pulley stationary half 53. The external thread cylindrical member 120 is secured to the inner race of a ball bearing 117 so as to be unable to move in the axial direction. Rotation of the external thread cylindrical member 120 is prevented from being transmitted to the driven pulley 53 by the ball bearing 117. A locking member 121 is secured to the external thread cylindrical member 120 and provided with an end secured to the transmission case 3 8 (not shown). Thus, the external thread cylindrical member 120 can maintain a stationary state with respect to the transmission case 38 in the axial and rotational directions, independently of the driven shaft 50 and the driven pulley 52. The internal thread cylindrical member 122 covers the external thread portion of the external thread cylindrical member 120 so as to be in threaded engagement therewith. An annular gear 123 is secured to the flange 122a of the internal thread cylindrical member 122 with bolts 124. The internal thread cylindrical member 122, the annular gear 123 and the bolts 124 constitute an internal thread assembly 125. A reduced diameter gear 142 of a second intermediate gear 144 described later drivingly rotates the annular gear 123. The internal thread cylindrical member 122 receives at the internal thread portion thereof a thrust force from the external thread portion of the fixed external thread cylindrical member 120 and is driven axially while being rotated. A disc spring 126 is interposed between the end of the internal cylindrical member 122 and the annular member 116 secured on the outer circumference of the ball bearing 115. With this configuration, the axial displacement of the internal thread cylindrical member 122 causes the driven pulley movable half 54 to move in the axial direction through the disk spring 126, the annular member 116, the ball bearing 115 and the cylindrical member 114. The external thread cylindrical member 120 and the internal thread assembly 125 constitute a thread-feeding mechanism 127. A speed change actuator 130 drivingly rotates the internal thread assembly 125. This actuator 130 is composed of an electric motor 131 and a reduction gear mechanism 132. The electric motor 131 is automatically controlled in rotation in accordance with vehicle speed, throttle opening, and internal combustion engine speed. A pressing force of the driven pulley movable half exerted on the V-belt is detected by measuring the strain of the disk spring 126 and is fed back for control. A reduction gear case 133 is fastened to the left transmission case 38L to define a reduction gear chamber 134 therebetween. An electric motor 131 is attached to the reduction gear case 133 via a fitting board 135. A pinion 136 formed on the rotating shaft of the motor extends into the reduction gear chamber 134. An enlarged diameter gear 137 in meshing engagement with the pinion 136 and a reduced diameter gear 138 adjacent thereto integrally constitute a first intermediate gear 139. The first intermediate gear 139 is supported for rotation by the left transmission case 38L and the reduction gear case 133 via ball bearings 140. An enlarged diameter gear 141 meshing engagement with the reduced diameter gear 138 and a reduced diameter gear 142 formed integrally and adjacently thereto are fitted onto a rotating shaft 143 to constitute a second intermediate gear 144. The second intermediate gear 144 is supported for rotation by the left transmission case 38L and the reduction gear case 133 via a ball bearing 145. The reduced diameter gear 142 is long in the axial direction so as to enable meshing engagement with the annular gear 123 of the internal thread assembly 125 at any axial position. Fig. 8 is an arrangement plan of gears, etc. showing the rear half of the transmission as viewed from the side. In the state of Fig. 7, when the electric motor 131 rotates in a normal direction in response to a control instruction, power is transmitted via the first and second intermediate gears 139, 144 to the internal thread assembly 125 in meshing engagement with the thread portion of the external thread cylindrical member 125 to rotate. This rotation of the internal thread assembly 125 moves itself in the axial direction of the driven shaft 50, thereby pressing the driven pulley movable half 54 via the disk spring 126, the annular member 116, the ball bearing 115 and the cylindrical member 114. This causes the distance between the driven pulley movable half 54 and the driving pulley stationary half 53 to be reduced, which displaces the V-belt in the circumferential direction. When the electric motor 131 is rotated in the reverse direction in response to a control instruction, according to the process reverse to that described above, the distance between the driven pulley stationary half 53 and the driven movable half 54 is increased to thereby displace the V-belt toward the center. Incidentally, the left stopper 121a of the internal thread assembly is provided at the other end of the locking member 121 in order to detect the limit of leftward movement of the internal thread assembly. An inner rotating member 51A of the centrifugal clutch 51 is secured to the right end face of the driven pulley stationary half with the bolts 147. An outer rotating member 51B of the centrifugal clutch 51 is fitted onto the driven shaft 50 via a spline 148 at a position facing the inner rotating member 51A so as to be unable to rotate relatively to each other. The outer circumference of the outside rotating member 51B covers the inner rotating member 51A. When the driven pulley reaches a predetermined rotating number, its rotation is transmitted via the inner rotating member 51A and the outer rotating member 51B to the driven shaft 50 to start to rotate. As described with reference to Fig. 2, the rotation of the driven shaft 50 is reduced by way of the gears of the reduction gear unit 46 and the rotation thus reduced is transmitted to the rear wheel shaft 60 for driving the rear wheel 5. The matters recited in claims corresponds to a portion relating to the axial driving mechanism of the driving pulley movable half 4 9 in the embodiment described above, the portion being described with reference to Figs. 3 to 6. In the description in the claims, "the thread-feeding mechanism" represents the thread-feeding mechanism 89 shown in Fig. 3, "the axially stationary side thread portion" represents the internal thread assembly 76, "the axial movable side thread portion" represents the internal cylindrical member 80, and "the axially movable side thread assembly" represents the external thread assembly 83. The V-belt type continuously variable transmission of the embodiment described above yields the following effects. (1) The input gear (annular gear 77) of the thread-feeding mechanism meshing with and driven by the final gear (the reduced diameter gear 102 of the second intermediate gear) of the reduction gear mechanism is included in the axially stationary side thread assembly (the internal thread assembly 79) and is unable to move axially. Therefore, the final gear (the reduced diameter gear 102 of the second intermediate) of the reduction gear mechanism can be reduced in width, thereby downsizing the transmission mechanism. (2) The axially movable side thread portion (the external thread cylindrical member 80) and the bearing member (ball bearing 72) are disposed by using the inside part in the width portion of the axially stationary thread portion (the internal thread cylindrical member 76) . Therefore, the transmission can be downsized by effectively utilizing the dead space. (3) One (the enlarged diameter gear 101 of the second intermediate gear) of the reduction gears is disposed by effectively utilizing the dead space defined between the input gear (the annular gear 77) of the axially stationary side thread assembly (the internal thread assembly 79) and the umbrella portion (the umbrella portion 49A of the driving pulley movable half) of the pulley movable half. Therefore, the transmission can be downsized. Furthermore, the continuously variable transmission of the embodiment simplifies its structure by providing the speed change actuator driven by the electric motor for each of the driving pulley and driven pulley, instead of the conjunction of the driving pulley with the driven pulley through the conventional complicate gear mechanism. The configuration of the present embodiment yields the following effects. (1) A space adapted for arrangement of the feeding mechanism can be secured with ease. In addition, the cooling performance of the electric motor can be ensured. (2) A space located on the outer surface side of each of both umbrella portions, of the driven pulley, confronting each other can be utilized effectively. (3) It is possible to adjust the lateral pressure of the V-belt, which can improve durability of the belt. (4) The thrust force can be adjusted by a simple structure comprising the spring, which makes it easy to optimize the lateral pressure of the belt at any time. (5) It is possible to easily exercise pulley-control in accordance with an adjustment amount of belt-lateral pressure. [Brief Description of the Drawings] [Fig. 1] Fig. 1 is a side view of a power unit according to the present invention. [Fig. 2] Fig. 2 is a cross-sectional development view depicting A-A section, B-B section and C-C section of Fig. 1 on a plane. [Fig. 3] Fig. 3 is an enlarged cross-sectional view depicting a state of a driving pulley and its periphery members assembled to a crack shaft. [Fig. 4] Fig. 4 is an enlarged cross-sectional view of only a shaft portion taken along IV-IV section of Fig. 3. [Fig. 5] Fig. 5 is a cross-sectional development view of the front half of a transmission. [Fig. 6] Fig. 6 is an arrangement plan of gears, etc. showing the front half of the transmission as viewed from the side. [Fig. 7] Fig. 7 is a cross-sectional development view of the rear half of the transmission. [Fig. 8] Fig. 8 is an arrangement plan of gears, etc. showing the rear half of the transmission. [Description of Reference Numerals] 11 ... crankshaft; 38 ... transmission case; 45 ... V-belt type continuously variable transmission; 47 ... driving pulley; 48 ... driving pulley stationary half; 49 ... driving pulley movable half; 49A ... umbrella portion; 49B ... cylindrical portion; 50 ... driven shaft; 51 ... centrifugal clutch; 52 ... driven pulley; 53 ... driven pulley stationary half; 55 ... endless V-belt; 72 ... ball bearing; 76 ... internal thread cylindrical member; 77 ... annular gear; 79 ... internal thread assembly; 80 ... external thread cylinder member; 81 ... locking member; 83 ... external thread assembly; 87 ... stroke sensor; 88 ... locking mechanism; 89 ... thread-feeding mechanism; 90 ... speed change actuator; 91 ... electric motor; 101 ... enlarged diameter gear; 102 ... reduced diameter gear; 104 ... second intermediate gear; 120 ... external thread cylindrical member; 122 ... internal thread cylindrical member; 125 ... internal tread assembly; 126 ... disc spring; 130 ... speed change actuator; 131 ... electric motor.

Full Text

[Name of Document] Specification
[Title of the Invention]
V-belt Type Continuously Variable Transmission
[Technical Field]
The present invention relates generally to a V-belt type continuously variable transmission and, in particular, to a mechanism for driving its pulley movable half and a variable gear ratio mechanism for the transmission.
[Background Art]
In a V-belt type continuously variable transmission, a pulley stationary half is fastened to a rotating shaft while a pulley movable half is attached to the rotating shaft so as to be unable to rotate relatively to each other and able to move in the axial direction. The thread feeding mechanism in the driving mechanism of a pulley movable half included in the conventional V-belt type continuously variable transmission is configured as below. An axially stationary side thread portion is held on a rotating shaft via a bearing and attached to a transmission case so as to be unable to rotate and move in the axial direction. An axially movable side thread portion is in meshing engagement with the outer circumferential thread of the above-mentioned axially

stationary side thread portion. This axially movable side thread portion is attached to the pulley movable half via a bearing so as to be able to rotate relatively to each other and unable to move in the axial direction. In addition, a motor drivingly rotates it through a reduction gear mechanism. When the motor is started up, the axially movable side thread portion moves axially, while rotating, to move the pulley movable half in the axial direction (for example, refer to Patent Document 1).
With the above-mentioned configuration, the axially movable side thread portion in meshing engagement, via a gear integral therewith, with the final gear of the reduction gear mechanism moves in itself in the axial direction while drivingly rotated. Therefore, it is necessary that the final gear of the reduction gear mechanism be in itself elongated in the axial direction, which causes the transmission mechanism to grow in size.
Also, a known example of the conventional techniques is that a distance between the stationary half and movable half of a driving pulley is controlled by a speed change actuator provided with an electric motor, while a distance between the stationary half and movable half of a driven pulley is set through a gear mechanism in conjunction with the driving pulley (e.g., refer to

Patent Document 2). This example provides a complicate interlocking mechanism.
[Patent Document 1] Patent No. 3099023 (Fig. 5) [Patent Document 2] Japanese Patent Laid-open No.
2001-330093 (Fig. 6) [Disclosure of the Invention] [Problems to be solved by the Invention]
A destination of the present invention is to provide a V-belt type continuously variable transmission capable of being reduced in size by improving the driving mechanism of a pulley movable half.
Another destination of the present invention is to simplify the structure of a variable gear ratio mechanism by providing a speed change actuator driven by an electric motor for each of a driving pulley and a driven pulley, instead of the conjunction of the driving pulley with the driven pulley through the conventional complicate gear mechanism. [Means for solving the Problems]
The present invention has solved the above-mentioned problem and the invention recited in claim 1 is a V-belt type continuously variable transmission comprising: a pulley stationary half which is fixedly supported on a rotating shaft; a pulley movable half which is supported

on the rotating shaft so as to face the pulley stationary-half and be movable axially while being inhibited from rotating relative to the rotating shaft, the pulley movable half in cooperation with the pulley stationary half gripping a belt therebetween; and a thread-feeing mechanism including: an axially stationary side thread assembly which is provided with an axially stationary side thread portion, held to be able to rotate relatively, while being inhibited from moving axially relative to the rotating shaft, and is drivingly rotated by an electric motor via a reduction gear mechanism; and an axially movable side thread assembly which is provided with an axially movable side thread portion fitted to the axially stationary side thread portion and is held movably in the axial direction of the rotating shaft while being inhibited from rotating relative to a transmission case; wherein the axially movable side thread assembly of the thread-feeding mechanism is attached to the pulley movable half so as to be unable to move axially, relatively to each other and be able to rotate relatively to each other.
The invention recited in claim 2 is, in the V-belt type continuously variable transmission recited in claim 1, the axially movable side thread portion is supported

on the pulley movable half through a bearing member so as to be able to rotate relatively to each other and unable to move axially, relatively to each other; and that the axially movable side thread portion and the bearing member are provided inside the axially stationary side thread portion.
The invention recited in claim 3 is, in the V-belt type continuously variable transmission recited in claim 1, one of reduction gears is disposed in a gap defined between an input gear of the axially stationary side thread assembly included in the thread-feeding mechanism and an umbrella portion of the pulley movable half.
The present invention has solved the above-mentioned problem and the invention recited in claim 4 is the V-belt type continuously variable transmission recited in claim 1, further including: a driving pulley including the stationary half and the movable half; a driven pulley including the stationary half and the movable half; and a speed change actuator provided for each of the driving pulley and the driven pulley; wherein the speed change actuator includes a feeding mechanism which engages with the movable half of each of the driving pulley and the driven pulley and an electric motor which drives the feeding mechanism, and the driving pulley and the driven

pulley are controlled independently of each other.
The invention recited in claim 5 is wherein, in the V-belt type continuously variable transmission recited in claim 4, the feeding mechanism for the driven pulley is disposed opposite to a clutch member across the stationary half and movable half of the driven pulley.
The invention recited in claim 6 is wherein, in the V-belt type continuously variable transmission recited in claim 4 or 5, at least one of the two feeding mechanisms includes a thrust force adjusting mechanism.
The invention recited in claim 7 is wherein, in the V-belt type continuously variable transmission recited in claim 4, the thrust force adjusting mechanism includes a spring.
The invention recited in claim 8 is wherein, in the V-belt type continuously variable transmission recited in claim 4, the thrust force adjusting mechanism includes a spring and a stroke sensor for detecting extension and contraction of the spring, and both the pulleys are controlled on the basis of a detected value of the stroke sensor. [Effects of the Invention]
In the invention of claim 1, the input gear of the thread-feeding mechanism meshing with and driven by the

final gear of the reduction gear mechanism is a gear of the axially stationary thread assembly, which does not move in the axial direction. Therefore, the final gear of the reduction gear mechanism can be reduced in width, so that the transmission can be downsized.
According to the invention of claim 2, the axially movable side thread portion and the bearing member are disposed by using the inside part in the width portion of the axially stationary thread portion. Therefore, the transmission can be downsized by effectively utilizing the dead space.
According to the invention of claim 3, one of the reduction gears is disposed by effectively utilizing the dead space defined between the input gear of the axially stationary side thread assembly and the umbrella portion of the pulley movable half. Therefore, the transmission can be downsized.
According to the invention of claim 4, a space adapted for arrangement of the feeding mechanism can be secured with ease. In addition, the cooling performance of the electric motor can be ensured.
According to the invention of claim 5, a space located on the outer surface side of each of both umbrella portions, of the driven pulley, confronting each

other can be utilized effectively.
According to the invention of claim 6, it is possible to adjust the lateral pressure of the V-belt, which can improve durability of the belt.
According to the invention of claim 7, the thrust force can be adjusted by a simple structure including the spring, which makes it easy to optimize the lateral pressure of the belt at any time.
According to the invention of claim 8, it is possible to easily exercise pulley-control in accordance with an adjustment amount of belt-lateral pressure. [Best Mode for Carrying out the Invention]
Fig. 1 is a side view of a power unit 1 according to the present invention. This power unit is mounted on a motorcycle and includes an overhead 4-stroke cycle 2-cylinder water-cooled internal combustion engine 2 fixed to a vehicle, a transmission 3, a rear wheel support portion 4 and a rear wheel, which are composed of in an integral manner. The transmission 3 is supported by the engine 2 so as to vertically swing around a crankshaft 11. Arrow F denotes the front of the internal combustion engine 2.
The engine 2 of the power unit 1 includes a crankcase 6, a cylinder block 7, a cylinder head 8, a

cylinder head cover 9 and a portion surrounded by such components. The cylinder block 7 facing forward and slightly upward is joined to the front end of the crankcase 6. The cylinder head 8 is joined to the front end of the cylinder block 7. The cylinder head cover 9 is joined to the front end of the cylinder head 8. A rear wheel shaft 60 is built in the rear wheel support portion 4 to transmit power from the engine to the rear wheel.
Fig. 2 is a cross-sectional development view depicting A-A section, B-B section and C-C section of Fig. 1 on a plane. The crankcase 6 is composed of a left crankcase 6L and a right crankcase 6R. The crankshaft 11 is carried for rotation by the respective journal bearings 10L and 10R of the left and right crankcases 6L and 6R. On the other hand, cylinder bores 12 are formed in the cylinder block 7 and respective pistons 13 are slidably fitted into the cylinder bores 12. A connecting rod 16 has two ends, one of which is pivotally supported by the crankshaft 11 via a crank pin 14 and the other of which is pivotally supported by the piston 13 via a piston pin 15. Reciprocation of the pistons 13 rotates the crankshaft 11. A combustion chamber 20 is defined on the bottom face of the cylinder head 8 facing the end face of the piston 13. An ignition plug 21 is attached

from the top of the cylinder head cover 9 in such a manner that the leading end of the ignition plug 21 faces the combustion chamber 20.
The cylinder head 8 is formed with an intake port and an exhaust port contiguous to the combustion engine 20. An intake valve and an exhaust valve are slidably fitted into the cylinder head 8. The intake valve opens/closes the opening of an intake port on the combustion chamber side and the exhaust valve opens/closes the opening of an exhaust port on the combustion chamber side. Fig. 2 depicts an exhaust valve 27 of a right combustion chamber.
In Fig. 2, a camshaft 28 is carried between the cylinder head 8 and the cylinder head cover 9 in parallel to the crankshaft 11. The intake valves and exhaust valves are drivingly opened and closed by cams formed on the camshaft 28. Fig. 2 depicts an exhaust cam 29. An endless chain 32 wound between a driving sprocket 30 and a driven sprocket 31 drivingly rotates the camshaft 28. The driving sprocket 30 is provided on the right-hand portion of the crankshaft 11 and the driven sprocket 31 on the right-hand portion of the camshaft 28.
A right crankcase cover 33 is provided on the outside of the right crankcase 6R. A generator 36 is made

up of a stator 34 fixed to the inner surface of the right crankcase cover 33 and a rotor 35. fixed to the crankshaft 11 to surround the stator 34. A driven gear 37 provided adjacently to the generator 36 is adapted to receive a rotary-driving force from a starter motor not shown.
A transmission case 38 is adapted to house therein the transmission 3 of the power unit 1. The transmission case 38 is composed of a right transmission case 38R, a left transmission case 38L and a partition wall 38S. The right transmission case 38R is movably supported on the left-hand and right-hand sides of the crankcase 6. On the left-hand side of the crankcase, as shown in Fig. 5, the right transmission case 38R is movably supported by a ball bearing 40. A support metal 39 attached to the left crankcase 6L with a bolt 22 holds the ball bearing 40. On the right-hand side of the crankcase, the right transmission case 38R is movably supported by connection metals 43A, 43B held by a roller bearing 42. A support metal 41 attached to the right crankcase cover 33 holds the roller bearing 42. The connection metals 43A, 43B are joined together with a bolt. A transmission case cover 23 is provided on the outside of the left transmission case 38L.
The left transmission case 38L and the partition

wall 38S are each joined to the right transmission case 38R with bolts. The rear end portion of the transmission case 38 for the transmission 3 serves as the rear wheel support portion 4. The transmission 3 is composed of a V-belt type continuously variable transmission 45 and a mechanical reduction gear unit 46. The continuously variable transmission 45 is provided such that its front half is disposed between the left transmission case 3 8L and the right transmission case 38R and its rear half is disposed between the left transmission case 38L and the partition wall 38S. In addition, the reduction gear unit
46 is disposed between the partition wall 38S and the
right transmission case 38R.
The driving shaft of the continuously variable transmission 45 is the crankshaft 11. A driving pulley 47 of the continuously variable transmission 45 is attached to the left end of the crankshaft 11. The driving pulley
47 is composed of a stationary half 48 and a movable half
49. A driven shaft 50 of the continuously variable
transmission 45 is carried for rotation by the left
transmission case 38L, the partition wall 38 and the
right transmission case 38R. A driven pulley 52 of the
continuously variable transmission 45 is attached to the
driven shaft 50 through a centrifugal clutch 51. The

driven pulley 52 is composed of a stationary half 53 and a movable half 54. An endless V-belt 55 is spanned between the driving pulley 47 and the driven pulley 52 so as to transmit rotation of the driving pulley 47 to the driven pulley 52. When the rotating speed of the driven pulley 52 exceeds a predetermined rotating speed, the centrifugal clutch 51 disposed between the driven pulley 52 and the driven shaft 50 comes into an engagement state, where the driven shaft 50 starts to rotate.
The reduction gear unit 46 is composed of gear groups carried on three rotating shafts. A first shaft is a right half portion of the driven shaft 50 of the transmission 45 carried by the right transmission case 38R and the partition wall 38S. The first shaft is formed with a reduced diameter gear 56 thereon. A second shaft is an intermediate shaft 57 carried for rotation by the right transmission case 38R and the partition wall 38S. The intermediate shaft 57 has an enlarged diameter gear 58 fitted integrally thereto, which meshes with the reduced diameter gear 56 of the driven shaft 50. In addition, the intermediate shaft 57 is formed with a reduced diameter gear 59 adjacent to the enlarged diameter gear 58. A third shaft is the rear wheel shaft 60 carried for rotation by the partition wall 38S, the

right transmission case 38R and an arm 62 which is joined to the connection metal 43A. The rear wheel shaft 60 has an enlarged diameter gear 62 fitted to thereto, which meshes with the reduced diameter gear 59 of the intermediate shaft 57. With this configuration, torque of the driven shaft 50 is reduced via the above-mentioned reduction gear group and transmitted to the rear wheel shaft 60. The rear wheel 5 is integrally fastened to the rear wheel shaft 60.
Fig. 3 is an enlarged cross-sectional view depicting a state of the driving pulley 47 and its periphery members assembled to the crack shaft 11. The driving pulley 47 is composed of the driving pulley stationary half 48 and the driving pulley movable pulley 49. The crankshaft 11 is formed at the left half portion thereof with a first reduced diameter portion 11A and a second reduced diameter portion 11B. The first reduced diameter portion 11A is defined between steps1 1a, 11b and the second reduced diameter portion 11B is defined between the step 11b and a crankshaft end face 11e. The first reduced diameter portion 11A is formed with a spline 11d at its end portion and the second reduced diameter portion 11B is formed with a spline 11e at its end portion.

The inner race of a ball bearing 63, a first support sleeve 64 and a guide sleeve 65 are fitted onto the first reduced diameter portion 11A. A second support sleeve 66 and the driving pulley stationary half 48 are fitted onto the second reduced diameter portion 11B. The sleeves 64, 65, 66 are made of steel and the driving pulley stationary half 48 is made of aluminum. The components mentioned above are fastened via a washer 67 with a bolt 6 8 that is screwed into a thread hole formed in the end of the crankshaft 11 and are secured so as to be unable to move in the direction of the crankshaft 11. Of the components mentioned above, the guide sleeve 65 is fitted onto the spline 11d of the first reduced diameter portion 11A via a spline 65a disposed inside the spline 11d. The driving pulley stationary half 48 is provided with a central hole and a spline 48a formed inside the central hole, and is fitted onto the spline 11e of the second reduced diameter portion 11B via the spline 48a. Thus, the components mentioned above are secured so as to be unable to move relative to the crankshaft 11. The driving pulley stationary half 48 is rotated together with the crankshaft 11.
The driving pulley movable half 49 is composed of an umbrella portion 49A confronting the stationary half, and

a cylindrical portion 49B which is formed integrally with the umbrella portion 49A so as to surround the sleeves 64, 65, 66 mentioned above. The umbrella portion 49A is made of an aluminum alloy and the cylindrical portion 49B is made of steel. The umbrella portion 49A is joined integrally to the flange portion of the cylindrical portion with rivets 44. The cylindrical portion 49B of the driving pulley movable half 49 is formed on the inside thereof with a projecting spline 49Ba projecting inward. The projecting spline 49Ba is fitted onto an outside spline 65b formed on the outer circumference of the guide sleeve 6 5. Since the outside spline 65b of the guide sleeve 65 extends in an axial direction, the projecting spline 4 9Ba is slidable in the axial direction in the guide groove thereof. Thus, while being unable to rotate relative to the crankshaft 11, the driving pulley movable half 49 is held movably in the axial direction. With the splines 11d, 65a, 65b, 49Ba, the driving pulley movable half 4 9 receives torque from the crankshaft 11 and rotates together with the crankshaft 11. Grease is applied to the groove of the outside spline 65b included in the guide sleeve 65, which allows the projecting spline 49Ba of the cylindrical portion 49B to slide smoothly. The movable half cylindrical portion 49B is

provided at both ends thereof with seals 69 for preventing leak of the grease and entering of dust.
Fig. 4 is an enlarged cross-sectional view of only a shaft portion (i.e., excluding the ball bearings, etc.) taken along line IV-IV of Fig. 3. The spline11d of the crankshaft 11 and the inner spline 6 5a of the guide sleeve 65 which are in meshing engagement with each other are each an involute spline. In addition, also the outer spline 65b of the guide sleeve 65 and the projecting spline 49Ba meshing therewith are each an involute spline. In order to enable air and grease to move along with movement of the projecting spline, clearances 70 are defined between the outer circumferential surface of the guide sleeve and the inner circumferential surface of the movable half cylindrical portion 49B.
In Fig. 3, a ball bearing outer race holding member 75 formed in a cylindrical shape holds the outer race of the ball bearing 63 attached to the crankshaft 11 so as to be unable to move relatively thereto in the axial direction. An internal thread cylindrical member 76 is integrally joined to an outer circumferential flange 75a of the ball bearing outer race-hoiding member 75 by welding. An annular gear 77 is joined to an outer circumferential flange 7 6a of the internal thread

cylindrical member 76 with bolts 78. The ball bearing outer race holding member 75, the internal thread cylindrical member 76 and the annular gear 77 are united to constitute an internal thread assembly 79. The crankshaft 11 with the ball bearing 63 carries this internal thread assembly 79 so that it can be rotated independently of the crankshaft 11 while being unable to move in the axial direction. The annular gear 77 of the internal thread assembly 79 is drivingly rotated by a reduced diameter gear 102 of a second intermediate gear 104 serving as part of a speed change actuator 90 described later.
The inner race of the ball bearing 72 is attached to the outer circumference of the cylindrical portion 49B included in the driving pulley movable half 49 so as to be unable to move in the axial direction. An external thread cylindrical member 80, specifically, its internal circumference, integrally holds the outer race of the ball bearing 72. The external circumferential threaded portion of the external thread cylindrical member 80 is in meshing engagement with the internal circumferential thread portion of the internal thread cylindrical member. A locking member 81 is fastened, with bolts 82, to a flange 80a formed at an end of the external thread

cylindrical member 80. The external thread cylindrical member 80, the locking member 81 and the bolts 82 are united to constitute an external thread assembly 83. The locking member 81 has a locking shaft portion 81, and projecting portions 81b formed to project from both sides of the locking shaft portion 81a. The projecting portions 81b engage respective locking guide rails 84 provided on the right transmission case 38R shown in Fig. 6 (side view) . Thus, when the internal thread assembly 7 9 is rotating, the external thread assembly 83 can move only in the axial direction of the crankshaft while inhibited from rotating about the crankshaft. The internal thread assembly 79 and the external thread assembly 83 constitute a thread-feeding mechanism 89.
A front stopper 81c is integrally formed on the arm portion of the locking member 81 in order to detect the limit of rearward displacement of the external thread assembly 83. A rear stopper 85 is attached, with a bolt 86, to the rear end of the shaft portion 81a included in the locking member 81 in order to detect the limit of forward displacement of the external thread assembly 83. The locking member 81 and the locking guide rails 84 (Fig. 6) constitute a locking mechanism 88 (Fig. 6).
The locking member 81 includes an extension 81d

formed externally of the shaft portion thereof. This extension 81d is in contact with the tip of a rod projecting from an end of a stroke sensor 87, which is used to detect the current position of the movable half. Stroke detection is made by detecting displacement of the rod that is pushed out of the end of the stroke sensor 87 by a spring. Rubber bellows surrounds the rod. The proximal portion of the stroke sensor 87 is connected to the right transmission case 38R.
Fig. 5 is a cross-sectional development view of the front half of the transmission 3. Fig. 6 is an arrangement plan of gears, etc. showing the front half of the transmission as viewed from the side. The speed change actuator 90 drivingly rotates the internal thread assembly 79. This actuator 9 0 is composed of an electric motor 91 and a reduction gear mechanism 92. The electric motor 91 is automatically controlled in rotation in accordance with vehicle speed, throttle opening, and internal combustion engine speed. A reduction gear case 93 is fastened to the right transmission case 38R. This reduction gear case 93 is composed of a right case member 93R, a left case member 93L and an end case member 93E, which define a reduction gear chamber 94 therebetween. The electric motor 91 is attached to the right case

member 93R of the reduction gear case 93 via an attachment plate 95. A pinion 96 formed on the rotating shaft of the motor extends into the reduction gear chamber 94.
An enlarged diameter gear 97 meshing with the pinion 9 6 and a reduced diameter gear 98 adjacent thereto are integrally formed to constitute a first intermediate gear 99. The first intermediate gear 99 is supported for rotation by the reduction gear case 93 via ball bearings 100.
An enlarged diameter gear 101 meshing with the reduced diameter gear 98 and a reduced diameter gear 102 adjacent integrally thereto which are fitted onto a rotating shaft 103 integrally constitute a second intermediate gear 104. The second intermediate gear 104 is supported for rotation by the reduction gear case 93 via ball bearings 105. The above-mentioned reduced diameter gear 102 is in meshing engagement with the annular gear 77 of the internal thread assembly 79 described earlier.
When the electric motor 91 rotates in a normal direction in response to a control instruction, power is transmitted via the first and second intermediate gears 99, 104 to the internal thread assembly 79 to rotate. The

threaded portion of the external cylindrical member 80 of the external thread assembly unable to rotate is in meshing engagement with the threaded portion of the internal thread cylindrical member 76. This threaded portion of the external thread assembly 80 receives a thrust force exerted in the axial direction of the crankshaft from the threaded portion of the internal thread cylindrical member 76. Thus, the external thread assembly 83 is moved in the axial direction of the crankshaft. The thrust force received by the threaded portion of the external cylindrical member 80 is transmitted via the ball bearings 72 to the driving pulley movable half 49 to move it in the axial direction of the crankshaft. This movement reduces the distance between the movable half 4 9 and the driving pulley stationary half 48 to thereby displace the V-belt in an outer circumferential direction. When the electric motor 91 is rotated in the reverse direction in response to a control instruction, according to the process reverse to that described above, the distance between the driving pulley stationary half 48 and the driving pulley movable half 49 is increased to thereby displace the V-belt toward the center.
Fig. 7 is a cross-sectional development view of the

rear half of the transmission 3. The driven pulley 52 is composed of the driven pulley stationary half 53 and the driven pulley movable half 54. The stationary half 53 is composed of an umbrella portion 53A made of aluminum and a cylindrical portion 53B made of steel. The driven pulley movable half 54 is also composed of an umbrella portion 54A made of aluminum and a cylindrical portion 54B made of steel. The umbrella portion of the stationary half 53 is fastened to the end of the cylindrical portion with bolts 147. The umbrella portion of the movable half 54 is integrally joined to the end of the cylindrical portion by casting.
The driven shaft 50 is formed with stepped portions 50a, 50b, and 50c. A ball bearing 110 is provided on the outer circumference of the driven shaft so as to be adjacent to the stepped portion 50a and a roller bearing 111 is provided on the outer circumference of the driven shaft so as to be adjacent to the stepped portion 50b. The cylindrical portion 53B of the stationary half 53 is supported by the ball bearing 110 and the roller bearing 111 for rotation relative to the driven shaft 50.
The cylindrical portion 54B of the movable half is fitted slidably to the outer circumference of the cylindrical portion 53B of the stationary half. Pins 112

are erectly provided at four points in the outer circumference of the cylindrical portion 53B of the stationary half. The cylindrical portion 54B of the movable half is formed with cam grooves 113, at four locations of the circumferential direction, each of which passes through the cylindrical portion 54B in the radial direction thereof and extends to slant with respect to the axial direction. The heads of the pins 112 are each fitted into a corresponding one of the cam grooves 113. Thus, the driven pulley movable half 54, while being restricted by the pins 112, can move toward the driven pulley stationary half 53 in the axial direction relatively to each other and in the circumferential direction of the cam grooves relatively to each other according to the angle of the cam grooves.
The cylindrical member 114 is secured to the outer circumference of the cylindrical portion 54B of the driven pulley movable half 54 so as to be unable to move in the axial direction for covering the cam grooves 113 of the cylindrical portion. Grease is applied in the cam groove 113 to assist the slide of the driven pulley movable half that is restricted by the pins 112. In addition, seals are provided inside both ends of the cylindrical member 114 so as to prevent oil from leaking

therefrom. The inner race of the ball bearing 115 is held on the outer circumference of the right end of the cylindrical member 114. An annular member 116 is brought into contact with the outer race of the ball bearing 115.
The inner race of a ball bearing 117 is fastened, with a nut 118, to a stepped portion that is provided on the outer circumference, and at the left end, of the cylindrical portion 53B of the pulley stationary half 53. The external thread cylindrical member 120 is secured to the inner race of a ball bearing 117 so as to be unable to move in the axial direction. Rotation of the external thread cylindrical member 120 is prevented from being transmitted to the driven pulley 53 by the ball bearing 117. A locking member 121 is secured to the external thread cylindrical member 120 and provided with an end secured to the transmission case 3 8 (not shown). Thus, the external thread cylindrical member 120 can maintain a stationary state with respect to the transmission case 38 in the axial and rotational directions, independently of the driven shaft 50 and the driven pulley 52.
The internal thread cylindrical member 122 covers the external thread portion of the external thread cylindrical member 120 so as to be in threaded engagement therewith. An annular gear 123 is secured to the flange

122a of the internal thread cylindrical member 122 with bolts 124. The internal thread cylindrical member 122, the annular gear 123 and the bolts 124 constitute an internal thread assembly 125.
A reduced diameter gear 142 of a second intermediate gear 144 described later drivingly rotates the annular gear 123. The internal thread cylindrical member 122 receives at the internal thread portion thereof a thrust force from the external thread portion of the fixed external thread cylindrical member 120 and is driven axially while being rotated. A disc spring 126 is interposed between the end of the internal cylindrical member 122 and the annular member 116 secured on the outer circumference of the ball bearing 115. With this configuration, the axial displacement of the internal thread cylindrical member 122 causes the driven pulley movable half 54 to move in the axial direction through the disk spring 126, the annular member 116, the ball bearing 115 and the cylindrical member 114. The external thread cylindrical member 120 and the internal thread assembly 125 constitute a thread-feeding mechanism 127.
A speed change actuator 130 drivingly rotates the internal thread assembly 125. This actuator 130 is composed of an electric motor 131 and a reduction gear

mechanism 132. The electric motor 131 is automatically controlled in rotation in accordance with vehicle speed, throttle opening, and internal combustion engine speed. A pressing force of the driven pulley movable half exerted on the V-belt is detected by measuring the strain of the disk spring 126 and is fed back for control.
A reduction gear case 133 is fastened to the left transmission case 38L to define a reduction gear chamber 134 therebetween. An electric motor 131 is attached to the reduction gear case 133 via a fitting board 135. A pinion 136 formed on the rotating shaft of the motor extends into the reduction gear chamber 134. An enlarged diameter gear 137 in meshing engagement with the pinion 136 and a reduced diameter gear 138 adjacent thereto integrally constitute a first intermediate gear 139. The first intermediate gear 139 is supported for rotation by the left transmission case 38L and the reduction gear case 133 via ball bearings 140.
An enlarged diameter gear 141 meshing engagement with the reduced diameter gear 138 and a reduced diameter gear 142 formed integrally and adjacently thereto are fitted onto a rotating shaft 143 to constitute a second intermediate gear 144. The second intermediate gear 144 is supported for rotation by the left transmission case

38L and the reduction gear case 133 via a ball bearing 145. The reduced diameter gear 142 is long in the axial direction so as to enable meshing engagement with the annular gear 123 of the internal thread assembly 125 at any axial position.
Fig. 8 is an arrangement plan of gears, etc. showing the rear half of the transmission as viewed from the side. In the state of Fig. 7, when the electric motor 131 rotates in a normal direction in response to a control instruction, power is transmitted via the first and second intermediate gears 139, 144 to the internal thread assembly 125 in meshing engagement with the thread portion of the external thread cylindrical member 125 to rotate. This rotation of the internal thread assembly 125 moves itself in the axial direction of the driven shaft 50, thereby pressing the driven pulley movable half 54 via the disk spring 126, the annular member 116, the ball bearing 115 and the cylindrical member 114. This causes the distance between the driven pulley movable half 54 and the driving pulley stationary half 53 to be reduced, which displaces the V-belt in the circumferential direction. When the electric motor 131 is rotated in the reverse direction in response to a control instruction, according to the process reverse to that described above,

the distance between the driven pulley stationary half 53 and the driven movable half 54 is increased to thereby displace the V-belt toward the center. Incidentally, the left stopper 121a of the internal thread assembly is provided at the other end of the locking member 121 in order to detect the limit of leftward movement of the internal thread assembly.
An inner rotating member 51A of the centrifugal clutch 51 is secured to the right end face of the driven pulley stationary half with the bolts 147. An outer rotating member 51B of the centrifugal clutch 51 is fitted onto the driven shaft 50 via a spline 148 at a position facing the inner rotating member 51A so as to be unable to rotate relatively to each other. The outer circumference of the outside rotating member 51B covers the inner rotating member 51A. When the driven pulley reaches a predetermined rotating number, its rotation is transmitted via the inner rotating member 51A and the outer rotating member 51B to the driven shaft 50 to start to rotate. As described with reference to Fig. 2, the rotation of the driven shaft 50 is reduced by way of the gears of the reduction gear unit 46 and the rotation thus reduced is transmitted to the rear wheel shaft 60 for driving the rear wheel 5.

The matters recited in claims corresponds to a portion relating to the axial driving mechanism of the driving pulley movable half 4 9 in the embodiment described above, the portion being described with reference to Figs. 3 to 6. In the description in the claims, "the thread-feeding mechanism" represents the thread-feeding mechanism 89 shown in Fig. 3, "the axially stationary side thread portion" represents the internal thread assembly 76, "the axial movable side thread portion" represents the internal cylindrical member 80, and "the axially movable side thread assembly" represents the external thread assembly 83.
The V-belt type continuously variable transmission of the embodiment described above yields the following effects.
(1) The input gear (annular gear 77) of the thread-feeding mechanism meshing with and driven by the final gear (the reduced diameter gear 102 of the second intermediate gear) of the reduction gear mechanism is included in the axially stationary side thread assembly (the internal thread assembly 79) and is unable to move axially. Therefore, the final gear (the reduced diameter gear 102 of the second intermediate) of the reduction gear mechanism can be reduced in width, thereby

downsizing the transmission mechanism.
(2) The axially movable side thread portion (the
external thread cylindrical member 80) and the bearing
member (ball bearing 72) are disposed by using the inside
part in the width portion of the axially stationary
thread portion (the internal thread cylindrical member
76) . Therefore, the transmission can be downsized by
effectively utilizing the dead space.
(3) One (the enlarged diameter gear 101 of the
second intermediate gear) of the reduction gears is
disposed by effectively utilizing the dead space defined
between the input gear (the annular gear 77) of the
axially stationary side thread assembly (the internal
thread assembly 79) and the umbrella portion (the
umbrella portion 49A of the driving pulley movable half)
of the pulley movable half. Therefore, the transmission
can be downsized.
Furthermore, the continuously variable transmission of the embodiment simplifies its structure by providing the speed change actuator driven by the electric motor for each of the driving pulley and driven pulley, instead of the conjunction of the driving pulley with the driven pulley through the conventional complicate gear mechanism. The configuration of the present embodiment yields the

following effects.
(1) A space adapted for arrangement of the feeding
mechanism can be secured with ease. In addition, the
cooling performance of the electric motor can be ensured.
(2) A space located on the outer surface side of
each of both umbrella portions, of the driven pulley,
confronting each other can be utilized effectively.
(3) It is possible to adjust the lateral pressure of
the V-belt, which can improve durability of the belt.
(4) The thrust force can be adjusted by a simple
structure comprising the spring, which makes it easy to
optimize the lateral pressure of the belt at any time.
(5) It is possible to easily exercise pulley-control
in accordance with an adjustment amount of belt-lateral
pressure.
[Brief Description of the Drawings]
[Fig. 1] Fig. 1 is a side view of a power unit according to the present invention.
[Fig. 2] Fig. 2 is a cross-sectional development view depicting A-A section, B-B section and C-C section of Fig. 1 on a plane.
[Fig. 3] Fig. 3 is an enlarged cross-sectional view depicting a state of a driving pulley and its periphery members assembled to a crack shaft.

[Fig. 4] Fig. 4 is an enlarged cross-sectional view of only a shaft portion taken along IV-IV section of Fig. 3.
[Fig. 5] Fig. 5 is a cross-sectional development view of the front half of a transmission.
[Fig. 6] Fig. 6 is an arrangement plan of gears, etc. showing the front half of the transmission as viewed from the side.
[Fig. 7] Fig. 7 is a cross-sectional development view of the rear half of the transmission.
[Fig. 8] Fig. 8 is an arrangement plan of gears, etc. showing the rear half of the transmission.
[Description of Reference Numerals]
11 ... crankshaft; 38 ... transmission case; 45 ... V-belt type continuously variable transmission; 47 ... driving pulley; 48 ... driving pulley stationary half; 49 ... driving pulley movable half; 49A ... umbrella portion; 49B ... cylindrical portion; 50 ... driven shaft; 51 ... centrifugal clutch; 52 ... driven pulley; 53 ... driven pulley stationary half; 55 ... endless V-belt; 72 ... ball bearing; 76 ... internal thread cylindrical member; 77 ... annular gear; 79 ... internal thread assembly; 80 ... external thread cylinder member; 81 ... locking member; 83 ... external thread assembly; 87 ... stroke sensor; 88 ... locking mechanism; 89 ...

thread-feeding mechanism; 90 ... speed change actuator; 91 ... electric motor; 101 ... enlarged diameter gear; 102 ... reduced diameter gear; 104 ... second intermediate gear; 120 ... external thread cylindrical member; 122 ... internal thread cylindrical member; 125 ... internal tread assembly; 126 ... disc spring; 130 ... speed change actuator; 131 ... electric motor.

Documents:

1240-CHE-2006 CORRESPONDENCE OTHERS.pdf

1240-CHE-2006 CORRESPONDENCE PO.pdf

1240-CHE-2006 FORM-3.pdf

1240-CHE-2006 FORM-5.pdf

1240-CHE-2006 PETITIONS.pdf

1240-che-2006-abstract.jpg

1240-che-2006-abstract.pdf

1240-che-2006-abstractimage.jpg

1240-che-2006-claims.pdf

1240-che-2006-correspondence-others.pdf

1240-che-2006-description-complete.pdf

1240-che-2006-drawings.pdf

1240-che-2006-form 1.pdf

1240-che-2006-form 18.pdf

1240-che-2006-form 26.pdf

1240-che-2006-form 3.pdf

1240-che-2006-form 5.pdf

1240-che-2006-priority document.pdf

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Patent Number

235238

Indian Patent Application Number

1240/CHE/2006

PG Journal Number

29/2009

Publication Date

17-Jul-2009

Grant Date

26-Jun-2009

Date of Filing

17-Jul-2006

Name of Patentee

HONDA MOTOR CO., LTD.

Applicant Address

1-1, MINAMI-AOYAMA 2-CHOME, MINATO-KU, TOKYO 107-8556.

Inventors:

#	Inventor's Name	Inventor's Address
1	ISHIKAWA, HIDEO	C/O HONDA R&D CO., LTD, 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA.
2	HAYASHI, AKIRA	C/O HONDA R&D CO., LTD, 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA.
3	ASUMI, MICHIO	C/O HONDA R&D CO., LTD, 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA.

PCT International Classification Number

F16H9/18

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2005-209577	2005-07-20	Japan
2	2005-252019	2005-08-31	Japan