Continuously variable transmission

Abstract

The present invention provides a continuously variable transmission (CVT) that can reduce the amount of misalignment between the center line of the groove of the drive pulley and the center line of the groove of the driven pulley, thereby reducing friction loss in the transmission members. [Solution] The continuously variable transmission (CVT) comprises a drive pulley (80) provided on an input shaft (32), a driven pulley (90) provided on an output shaft (120), and a transmission member (100) between the drive pulley (80) and the driven pulley (90), and in a CVT in which stepless speed changes are performed by changing the winding radius of the transmission member (100) between the drive pulley (80) and the driven pulley (90), the CVT has a misalignment adjustment mechanism (140) that reduces the amount of misalignment (δ) between the center line (80a) of the drive pulley (80) and the center line (90a) of the driven pulley (90) by moving the driven pulley (90) in the axial direction due to the reaction force of the driving force.

Description

Technical Field

[0001] The present invention relates to a continuously variable transmission.

Background Art

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, research and development have been carried out on continuously variable transmissions that contribute to energy efficiency. As a technology related to continuously variable transmissions, Patent Document 1 discloses a belt-type continuously variable transmission with a general structure. In Patent Document 1, in each of the driving pulley and the driven pulley, one is a fixed pulley and the other is a movable pulley, and the movable pulleys in the driving pulley and the driven pulley are arranged diagonally.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the present technology related to continuously variable transmissions, in the belt-type continuously variable transmission having the structure described in Patent Document 1, there is a problem that the center of the width of the belt is displaced between the driving pulley and the driven pulley, and there is a risk that the friction loss increases due to the load applied to the side surface of the belt. The present invention has been made in view of the above circumstances, and an object thereof is to provide a continuously variable transmission capable of reducing the amount of displacement between the center line of the groove of the driving pulley and the center line of the groove of the driven pulley in the continuously variable transmission, and reducing the friction loss generated in the transmission member. And by extension, it contributes to energy efficiency.

Means for Solving the Problems

[0005] A continuously variable transmission (CVT) comprises a drive pulley provided on an input shaft, a driven pulley provided on an output shaft, and a transmission member wrapped between the drive pulley and the driven pulley, wherein stepless speed changes are performed by changing the wrapping radius of the transmission member between the drive pulley and the driven pulley. The CVT is characterized by having a misalignment adjustment mechanism that reduces the amount of misalignment between the center line of the groove of the drive pulley and the center line of the groove of the driven pulley by moving the driven pulley in the axial direction due to the reaction force of the driving force. [Effects of the Invention]

[0006] This invention provides a continuously variable transmission (CVT) that can reduce the amount of misalignment between the center line of the groove in the drive pulley and the center line of the groove in the driven pulley, thereby reducing friction loss in the transmission members. [Brief explanation of the drawing]

[0007] [Figure 1] This is a side view of a saddle-type vehicle according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view of a power unit according to the first embodiment. [Figure 3] This figure shows the peripheral portion of the displacement adjustment mechanism according to the first embodiment. [Figure 4] This is a perspective view of the driven shaft according to the first embodiment. [Figure 5] This is a graph showing the relationship between the gear ratio TR of a V-belt type transmission and the axial load LD acting on the driven shaft. [Figure 6] This figure shows the peripheral portion of the displacement adjustment mechanism according to the second embodiment. [Figure 7] This figure shows the peripheral portion of the displacement adjustment mechanism according to the third embodiment. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. In the description, directions such as front, back, left, right, and up and down refer to directions relative to the vehicle body unless otherwise specified. In each figure, the symbol FR indicates the front of the vehicle body, the symbol UP indicates the top of the vehicle body, and the symbol LH indicates the left side of the vehicle body.

[0009] [Embodiment] Figure 1 is a side view of a saddle-type vehicle 10 according to an embodiment of the present invention. The saddle-type vehicle 10 is a vehicle that comprises a body frame 11, a power unit 12 supported by the body frame 11, a front fork 14 that supports the front wheel 13 in a steerable manner, a swing arm 16 that supports the rear wheel 15, and a seat 17 for the rider. The saddle-type vehicle 10 is a vehicle in which the occupant sits straddling a seat 17. The seat 17 is located above the rear of the vehicle frame 11.

[0010] The vehicle frame 11 comprises a head pipe 18 located at the front end of the vehicle frame 11, a front frame 19 located behind the head pipe 18, and a rear frame 20 located behind the front frame 19. The front end of the front frame 19 is connected to the head pipe 18. The seat 17 is supported by the rear frame 20.

[0011] The front fork 14 is supported by a head pipe 18 so that it can be steered left and right. The front wheel 13 is supported by an axle 13a located at the lower end of the front fork 14. A steering handle 21, which is held by the rider, is attached to the upper end of the front fork 14.

[0012] The swingarm 16 is supported by a pivot shaft 22 which is supported by the vehicle frame 11. The pivot shaft 22 is an axis that extends horizontally in the vehicle width direction. The pivot shaft 22 is inserted through the front end of the swingarm 16. The swingarm 16 swings up and down around the pivot shaft 22. The rear wheel 15 is supported by an axle 15a located at the rear end of the swing arm 16.

[0013] The power unit 12 is disposed between the front wheel 13 and the rear wheel 15 and is supported by the vehicle body frame 11. The power unit 12 is an internal combustion engine. The power unit 12 includes a crankcase 23 and a cylinder unit 24 that houses a reciprocating piston. An exhaust device 25 is connected to the exhaust port of the cylinder unit 24. The output of the power unit 12 is transmitted to the rear wheel 15 by a driving force transmission member that connects the power unit 12 and the rear wheel 15.

[0014] Further, the saddle-type vehicle 10 includes a front fender 26 that covers the front wheel 13 from above, a rear fender 27 that covers the rear wheel 15 from above, a step 28 on which a rider places his or her feet, and a fuel tank 29 that stores fuel used by the power unit 12. The front fender 26 is attached to the front fork 14. The rear fender 27 and the step 28 are provided below the seat 17. The fuel tank 29 is supported by the vehicle body frame 11.

[0015] In the present embodiment, the saddle-type vehicle 10 is a scooter-type saddle-type vehicle. The saddle-type vehicle 10 has a low-floor step 28 on which a rider seated on the seat 17 places his or her feet, that is, a so-called step floor. Further, the power unit 12 is a unit swing engine supported by the rear portion of the vehicle body frame 11. The power unit 12 has an engine body 30 and a swing arm 16 provided integrally. The rear wheel 15, which is a drive wheel, is pivotally supported by the power unit 12 disposed at the rear of the vehicle. The power unit 12 is located directly below the seat 17 when viewed from the side of the vehicle.

[0016] The engine body 30 includes a crankcase 23 and a cylinder portion 24 extending forward from the crankcase 23. As shown in FIG. 2, the cylinder portion 24 includes a cylinder 24a, a cylinder head 24b, and a head cover 24c in order from the crankcase 23 side. The engine body 30 is a horizontal engine in which the cylinder axis 24d of the cylinder portion 24 extends substantially horizontally in the vehicle longitudinal direction. Specifically, the cylinder portion 24 extends substantially horizontally forward in a slightly upward direction in the vehicle side view.

[0017] As shown in FIG. 1, the rear frame 20 includes a pair of left and right frame rising portions 20a that extend rearward and upward in front of the crankcase 23. The cylinder portion 24 extending forward from the crankcase 23 is located in the space between the left and right frame rising portions 20a. The power unit 12 is swingably supported on the pivot shaft 22 of the frame rising portion 20a via a link mechanism 31 provided above the power unit 12.

[0018] FIG. 2 is a cross-sectional view of the power unit 12 according to the first embodiment. FIG. 2 is a view looking from above at a cross-section passing through the axes of the camshaft 51 of the valve operating device 50 of the cylinder head 24b, the crank pin 39, the crankshaft 32, the driven shaft 120, the transmission shaft 150, and the axle 15a. The crankcase 23 supports a crankshaft (drive shaft, input shaft) 32. The crankshaft 32 extends in the left-right direction (vehicle width direction). A crank chamber 33 for housing the crankshaft 32 is formed in the crankcase 23. A pair of left and right support walls 34a and 34b orthogonal to the crankshaft 32 are provided in the crank chamber 33. The crankshaft 32 is rotatably supported on the support walls 34a and 34b via bearings 35a and 35b.

[0019] A piston 40 is connected to the crankshaft 32 via a connecting rod 38 and a crank pin 39. The piston 40 reciprocates in the cylinder 24a in the axial direction of the cylinder axis 24d.

[0020] A drive sprocket 41 is mounted on the crankshaft 32 to the left of the connecting rod 38. A cam chain 42 is wrapped around the drive sprocket 41. The cam chain 42 passes through a cam chain chamber 43 formed on the left side of the cylinder section 24 and is wrapped around the driven sprocket 52 of the camshaft 51 of the valve train 50.

[0021] The camshaft 51 of the valve train 50 is parallel to the crankshaft 32. The valve train 50 is mounted on the cylinder head 24b. The rotation of the crankshaft 32 is transmitted to the camshaft 51 via a driven sprocket 52 by a cam chain 42. The camshaft 51 rotates once for every two rotations of the crankshaft 32. The rotation of the camshaft 51 drives intake and exhaust valves (not shown) to perform intake and exhaust according to the cycle.

[0022] The right end 32R of the crankshaft 32 penetrates the right support wall 34b and extends to the right side of the crankcase 23. A flywheel 55 that rotates integrally with the crankshaft 32 is fixed to the right end 32R of the crankshaft 32. A generator 56 that generates electricity by the rotation of the crankshaft 32 is provided radially inward of the flywheel 55.

[0023] The power unit 12 is equipped with a blower 57 that blows air toward the engine body 30 to air cool the engine body 30. The blower 57 comprises a crankshaft 32, a cooling fan 57a ​​fixed to the crankshaft 32 and rotating integrally with the crankshaft 32, a fan cover 57b covering the cooling fan 57a ​​from the outside, and a cylinder section cover 57c covering the cylinder section 24.

[0024] The space formed between the cylinder section cover 57c and the cylinder section 24 is an air passage 58 through which the airflow supplied by the cooling fan 57a ​​passes. Within the air passage 58, cooling fins 24a1 are provided on the outer surface of the cylinder 24a.

[0025] The crankcase 23 integrally includes a transmission case 61 that extends rearward from the left side of the crank chamber 33. The transmission case 61 extends from the left side of the crank chamber 33 to the left side of the rear wheel 15.

[0026] The transmission case 61 is formed in a case shape with an open outer surface in the vehicle width direction. The open outer surface of the transmission case 61 is closed by a case cover 62 attached to the outer surface of the transmission case 61. In this embodiment, the rear end of the transmission case 61 is closed by a reduction gear cover 65 attached to the inner surface of the transmission case 61 in the vehicle width direction. The transmission case 61, case cover 62, and reduction gear cover 65 constitute the swing arm 16 of this embodiment.

[0027] In this embodiment, the swing arm 16 has a hollow transmission chamber 63 formed by the transmission case portion 61 and the case cover 62. Furthermore, the transmission case portion 61 and the reduction gear cover 65 form a hollow reduction mechanism housing chamber 66.

[0028] Inside the transmission chamber 63, the left end 32L of the crankshaft 32 is located, passing through the left support wall 34a. The transmission chamber 63 is equipped with a transmission 70 that changes the speed of the rotation of the crankshaft 32 and transmits it to the rear wheel 15.

[0029] The transmission 70 includes a V-belt type transmission (belt-type continuously variable transmission, continuously variable transmission) 71 and a starting clutch (centrifugal clutch) 72. The V-belt type transmission 71 includes a drive pulley 80 provided at one axial end (left end) of the crankshaft 32, a driven pulley 90 provided at one axial end (left end) of a driven shaft (output shaft) 120 that is pivotally supported parallel to the rear of the crankshaft 32, and a V-belt (transmission member) 100 stretched between the drive pulley 80 and the driven pulley 90.

[0030] The drive pulley 80 has a fixed sheave (half of the drive pulley) 81 fixed to the crankshaft 32, and a movable sheave (half of the driven pulley) 82 (see the solid and dashed lines in Figure 2) positioned opposite the fixed sheave 81 and supported by the crankshaft 32 so as to be movable in the axial direction. A V-belt 100 is sandwiched between the fixed sheave 81 and the movable sheave 82.

[0031] The movable sheave 82 is configured to move in the axial direction of the crankshaft 32 by the action of a weight roller 83 that moves due to the centrifugal force caused by the rotation of the crankshaft 32. That is, the axial distance between the movable sheave 82 and the fixed sheave 81 changes as the crankshaft 32 rotates, and the winding diameter of the V-belt 100 sandwiched between the movable sheave 82 and the fixed sheave 81 changes. In this embodiment, when simply referred to as "axial direction," it means the direction parallel to the axial direction in which the crankshaft 32 extends.

[0032] The driven pulley 90 comprises a cylindrical shaft portion 91 rotatably mounted on the driven shaft 120, a fixed sheave (half of the driven pulley) 92 fixed to the shaft portion 91, and a movable sheave (half of the driven pulley) 93 positioned opposite the fixed sheave 92 and supported to move freely in the axial direction of the shaft portion 91. The V-belt 100 is sandwiched between the fixed sheave 92 and the movable sheave 93. In the driven pulley 90, the movable sheave 93 is provided on the opposite side of the V-belt 100 from the movable sheave 82 of the drive pulley 80.

[0033] The movable sheave 93 is biased toward the fixed sheave 92 by a coil spring (driven biasing member) 94. The movable sheave 93 pushes the V-belt 100 downward in the width direction of the V-belt 100. That is, as the winding diameter on the drive pulley 80 side changes and the V-belt 100 is pulled, the axial distance between the movable sheave 93 and the fixed sheave 92 changes, and the winding diameter of the V-belt 100 sandwiched between the movable sheave 93 and the fixed sheave 92 becomes variable.

[0034] In the V-belt type transmission 71, the movable sheave 82 of the drive pulley 80 and the movable sheave 93 of the driven pulley 90 are displaced in the axial direction, which changes the winding diameter of the drive pulley 80 and the driven pulley 90 with respect to the V-belt 100, and thus the gear ratio is changed steplessly.

[0035] In this embodiment, when the gear ratio is at its highest setting, the center line 80a of the groove width of the drive pulley 80, i.e., the center line 80a of the groove formed by the fixed sheave 81 and the movable sheave 82, and the center line 90a of the groove width of the driven pulley 90, i.e., the center line 90a of the groove formed by the fixed sheave 92 and the movable sheave 93, are set to coincide in the axial direction (vehicle width direction). In other words, when the gear ratio is at its highest setting, the width center of the V-belt 100 wrapped around the drive pulley 80 and the width center of the V-belt 100 wrapped around the driven pulley 90 are set to coincide in the axial direction.

[0036] A starting clutch 72 is positioned between the driven pulley 90 and the driven shaft 120. The driven pulley 90 and the driven shaft 120 are connected and disconnected via the starting clutch 72. The rotational force of the driven pulley 90 is transmitted to the driven shaft 120 when the starting clutch 72 is engaged. The rotation of the driven shaft 120 is transmitted to the rear wheel 15 via a reduction mechanism (power transmission mechanism) 73 provided in the reduction mechanism housing chamber 66. Thus, the saddle-type vehicle 10 starts moving. The transmission 70 constitutes a vehicle power transmission device that transmits the driving force generated by the engine body 30 to the rear wheel 15.

[0037] Figure 3 shows the peripheral portion of the displacement adjustment mechanism 140 according to the first embodiment. Figure 3 corresponds to the enlarged view of the main part of Figure 2. As shown in Figure 3, the shaft portion 91 of the driven pulley 90 is rotatably supported on the driven shaft 120 via bearings 95 and 96. The bearings 95 and 96 are positioned between the inner circumference of the shaft portion 91 and the outer circumference of the driven shaft 120. In this embodiment, bearing 95 is a needle bearing, and bearing 96 is a ball bearing. The shaft portion 91 is rotatable on the driven shaft 120 but immovable in the axial direction.

[0038] A fixed sheave 92 is fixed to the right end (one end in the axial direction) of the shaft portion 91. The fixed sheave 92 moves integrally with the shaft portion 91. The fixed sheave 92 is rotatable relative to the driven shaft 120, but is immovable in the axial direction. In other words, the "fixed" nature of the fixed sheave 92 means that it is immovable in the axial direction.

[0039] A ring-shaped support plate 97 is fixed to the left end (the other end in the axial direction) of the shaft portion 91, extending radially outward from the shaft portion 91. The support plate 97 rotates integrally with the shaft portion 91.

[0040] Between the fixed sheave 92 and the support plate 97, a cylindrical movable sheave shaft portion 98 is mounted on the outer circumference of the shaft portion 91. A movable sheave 93 is fixed to the right end of the movable sheave shaft portion 98. The movable sheave shaft portion 98 and the movable sheave 93 are rotatable relative to the shaft portion 91 and are also movable in the axial direction.

[0041] A cylindrical coil spring 94 is positioned between the movable sheave 93 and the support plate 97, extending in the axial direction of the shaft portion 91. The coil spring 94 has a larger diameter than the movable sheave shaft portion 98. The coil spring 94 is compressed between the support plate 97 and the movable sheave 93. The coil spring 94 biases the movable sheave 93 axially toward the fixed sheave 92.

[0042] The fixed sheave 92 and the movable sheave 93 are provided with a cam mechanism 99 that converts the rotation of the movable sheave 93 into axial thrust of the movable sheave 93. The thrust is the force that moves the movable sheave 93 in the direction of the fixed sheave 92.

[0043] The cam mechanism 99 includes a cam pin portion 99a extending radially outward from the shaft portion 91 and a cam receiving portion 99b provided on the movable sheave shaft portion 98.

[0044] The cam pin portion 99a is cylindrical in shape and protrudes radially outward from the outer circumference of the shaft portion 91. The cam pin portion 99a fits into the cam receiving portion 99b.

[0045] The cam receiving portion 99b is an elongated hole extending axially on the movable sheave shaft portion 98. The cam receiving portion 99b is formed to be inclined diagonally in a linear manner, for example, so that it shifts circumferentially on the movable sheave shaft portion 98 as it advances axially. The movable sheave 93 is movable relative to the shaft portion 91, which is integrated with the fixed sheave 92, because the cam receiving portion 99b is guided by the cam pin portion 99a.

[0046] The relative movement of the movable sheave 93 with respect to the shaft portion 91, which is integrated with the fixed sheave 92, is restricted to a predetermined range by the cam mechanism 99. In detail, the movable sheave 93 is circumferentially rotatable and axially movable within the range of motion of the cam receiving portion 99b relative to the cam pin portion 99a.

[0047] When the rotational torque input from the V-belt 100 to the driven pulley 90 fluctuates, the movable sheave 93 is rotated relative to the fixed sheave 92 by the V-belt 100. At this time, the relative rotation of the movable sheave 93 is converted into axial thrust by the cam mechanism 99, and the movable sheave 93 moves in the axial direction. Therefore, the force with which the movable sheave 93 grips the V-belt 100 is changed, and the cam mechanism 99 can change the gear ratio in accordance with the torque fluctuation. The driven pulley 90 of this embodiment is composed of a shaft 91, a fixed sheave 92, a movable sheave 93, a coil spring 94, bearings 95 and 96, a support plate 97, and the like.

[0048] As shown in Figure 3, the starting clutch 72 comprises a plurality of support shafts 111 supported by a support plate 97, a clutch shoe 112 that is pivotably supported on each support shaft 111 and extends in the circumferential direction, a clutch spring 113 that biases the clutch shoe 112, and a clutch outer 114 that surrounds the support plate 97 and the clutch shoe 112 from the outer circumference.

[0049] The clutch shoe 112 is positioned radially outward from the coil spring 94 on the support plate 97. The clutch shoe 112 is erected from the support plate 97 toward the movable sheave 93. The clutch spring 113 biases the clutch shoe 112 so that it swings radially inward from the starting clutch 72. In other words, the clutch spring 113 biases the clutch shoe 112 in a direction that disconnects the connection by the starting clutch 72.

[0050] The clutch outer 114 is a cup-shaped member that extends radially outward from the driven shaft 120. The clutch outer 114 is spline-fitted to the shaft end of the driven shaft 120. The clutch outer 114 is secured by a nut 115 fastened to the driven shaft 120. The clutch outer 114 rotates integrally with the driven shaft 120.

[0051] When driving force is transmitted to the driven pulley 90 via the V-belt 100, the driven pulley 90 rotates on the driven shaft 120 via bearings 95 and 96. As the support plate 97 of the driven pulley 90 rotates, centrifugal force acts on the clutch shoe 112 of the starting clutch 72. When the rotation of the driven pulley 90 exceeds a predetermined rotational speed, the clutch shoe 112 swings radially outward against the clutch spring 113 and contacts the inner circumference of the clutch outer 114. The frictional force from this contact engages the starting clutch 72. When the starting clutch 72 is engaged, rotation is transmitted from the clutch shoe 112 to the driven shaft 120 via the clutch outer 114. The rotation of the driven shaft 120 is transmitted to the rear wheel 15 via the reduction mechanism 73.

[0052] Figure 4 is a perspective view of the driven shaft 120 according to the first embodiment. The driven shaft 120 extends in the left-right direction. The driven shaft 120 is formed in a stepped shape. Specifically, the driven shaft 120 has a bearing mounting portion 121 in the left-right central part (axial central part). A tapered portion 121a is formed on the left side (axial side) of the bearing mounting portion 121. The diameter of the tapered portion 121a decreases as it moves to the left. A pin avoidance portion 122 is formed to the left of the tapered portion 121a. A stepped recessed bearing receiving portion 123 is formed to the left of the pin avoidance portion 122.

[0053] A clutch support portion 124 with a spline is formed on the left side of the bearing support portion 123. A threaded portion 125 is formed on the left side of the clutch support portion 124. A left end shaft portion 126, which has a smaller diameter than the threaded portion 125, is formed on the left side of the threaded portion 125.

[0054] On the right side (the other side in the axial direction) of the bearing mounting portion 121, a bearing receiving portion 121b is formed that protrudes radially. A helical gear 127 is formed on the right side of the bearing receiving portion 121b. The tooth traces of the helical gear 127 extend along the axial direction. The tooth traces of the helical gear 127 are inclined more towards the front in the rotational direction R on the right side compared to the left side. The helical gear 127 is formed with a so-called left-hand twist. On the right side of the helical gear 127, a right-end shaft portion 128 with a smaller diameter than the helical gear 127 is formed. A spring housing portion (biasing member housing portion) 128a (see Figure 3) is formed on the right-end shaft portion 128 that is recessed to the left from the right end.

[0055] As shown in Figures 2 to 4, the driven shaft 120 is positioned across the transmission chamber 63 and the reduction mechanism housing chamber 66. The driven shaft 120 is positioned from the reduction mechanism housing chamber 66 to the transmission chamber 63, passing through the transmission case portion 61. A bearing 131 is mounted on the bearing mounting portion 121 of the driven shaft 120. The bearing 131 comprises an outer race 131a, an inner race 131b, and a plurality of balls 131c supported between the outer race 131a and the inner race 131b. The outer race 131a is fixed to the transmission case portion 61 by press-fitting.

[0056] Adjacent to the bearing 132, an oil seal 134 is mounted on the driven shaft 120. The oil seal 134 is positioned between the reduction gear housing chamber 66 and the transmission chamber 63. The oil seal 134 prevents lubricating oil from leaking from the reduction gear housing chamber 66 to the transmission chamber 63.

[0057] The left end shaft portion 126 of the driven shaft 120 is rotatably supported by the case cover 62 via a bearing 132. The bearing 132 comprises an outer race 132a, an inner race 132b, and a plurality of balls 132c supported between the outer race 132a and the inner race 132b. The outer race 132a is fixed to the case cover 62 by press-fitting.

[0058] The right end shaft portion 128 of the driven shaft 120 is rotatably supported by the gearbox cover 65 via a bearing 133. The bearing 133 comprises an outer race 133a, an inner race 133b, and a plurality of balls 133c supported between the outer race 133a and the inner race 133b. The outer race 133a is fixed to the gearbox cover 65 by press-fitting.

[0059] Here, the driven shaft 120 is provided with a misalignment adjustment mechanism 140. The misalignment adjustment mechanism 140 in this embodiment includes a cap-shaped spring seat 141 positioned on the right end shaft portion 128 of the driven shaft 120. The spring seat 141 has a bottomed cylindrical housing portion 141a extending in the axial direction and a flange portion 141b formed at the axial inner end of the housing portion 141a.

[0060] The right end shaft portion 128 of the driven shaft 120 is inserted into the spring seat 141. The right end shaft portion 128 is housed so as to be axially slidable relative to the spring seat 141. In other words, the right end shaft portion 128 is loosely supported relative to the spring seat 141.

[0061] The spring seat 141 is fixed to the inner race 133b of the bearing 133 by press-fitting. The outer diameter of the flange portion 141b of the spring seat 141 is smaller than the outer diameter of the inner race 133b. Therefore, the spring seat 141 is in contact with the inner race 133b of the bearing 133. A predetermined gap S0 can be formed between the spring seat 141 and the right end (other axial end) of the helical gear 127. The predetermined gap S0 is determined by the amount of displacement δ of the centerlines 80a and 90a when the V-belt type transmission 71 is at a low ratio.

[0062] A coil spring (spring mechanism) 142 is housed in the spring housing portion 128a of the right end shaft portion 128 of the driven shaft 120. The coil spring 142 is covered by a spring seat 141. This maintains the coil spring 142 in a compressed state. The coil spring 142 biases the driven shaft 120 to the left (one side in the axial direction).

[0063] Here, the driven shaft 120 is supported so as to be axially slidable with respect to the inner races 131b and 132b of the bearings 131 and 132. In other words, the driven shaft 120 is loosely supported with respect to the inner races 131b and 132b of the bearings 131 and 132. Generally, for example, the driven shaft 120 is lightly press-fitted into the inner race 131b of the bearing 131, but in this embodiment, the driven shaft 120 is not lightly press-fitted and is loosely supported by the inner races 131b and 132b.

[0064] A reduction gear 73 is housed in the reduction gear chamber 66. The reduction gear 73 has a transmission shaft 150 that extends parallel to the driven shaft 120. The transmission shaft 150 is rotatably supported in the axial direction via a pair of bearings 135, 136. A first gear 151, which is a spur gear, is supported at the right end of the transmission shaft 150. The first gear 151 meshes with the helical gear 127 of the driven shaft 120.

[0065] A second gear 152, which is a spur gear, is provided at the left end of the transmission shaft 150. The second gear 152 meshes with a driven gear 153, which is a spur gear supported by the axle 15a. The axle 15a is rotatably supported via bearings 137 and 138. The rear wheel 15 is supported on the axle 15a. When the axle 15a rotates, the rear wheel 15 rotates.

[0066] In this embodiment, the reduction mechanism 73 is composed of a helical gear 127 on the driven shaft 120, a transmission shaft 150, a first gear 151, a second gear 152, and a driven gear 153. The reduction mechanism 73 reduces the rotation of the driven shaft 120 by a predetermined reduction ratio and transmits it to the axle 15a. The reduction mechanism 73 may also be configured to further include other gears and transmission shafts, and to reduce the rotation using multiple gears.

[0067] In this embodiment, the misalignment adjustment mechanism 140 is composed of a driven shaft 120, a helical gear 127, a first gear 151, a spring seat 141, a coil spring 142, and bearings 131, 132, and 133.

[0068] Figure 5 is a graph showing the relationship between the gear ratio TR of a V-belt type transmission 71 and the axial load LD acting on the driven shaft 120. In Figure 5, the horizontal axis represents the gear ratio TR and the vertical axis represents the load LD. When the crankshaft 32 rotates, the drive pulley 80 rotates in the V-belt type transmission 71, and the driven pulley 90 rotates via the V-belt 100. At this time, when the starting clutch 72 is engaged, the rotational driving force from the driven pulley 90 is transmitted to the driven shaft 120, and the rear wheel 15 is driven via the reduction mechanism 73 that meshes with the helical gear 127 of the driven shaft 120.

[0069] In this process, the twisting of the helical gear 127 generates a reaction force against the rotational torque of the driven shaft 120 at the meshing portion between the helical gear 127 and the first gear 151. That is, a thrust load LD is generated on the driven shaft 120, causing it to move to the right (the other axial direction). As shown in Figure 5, the larger the gear ratio TR and the higher the torque, the greater the thrust load LD generated at the meshing portion. In Figure 5, the thrust load LD generated on the driven shaft 120 by the helical gear 127 is shown by solid lines for low torque T1, medium torque T2 (greater than low torque T1), and high torque T3 (greater than medium torque T2).

[0070] Here, the driven shaft 120 is biased axially to the left by the coil spring 142. Therefore, when the biasing force of the coil spring 142 is sufficiently acting on the driven shaft 120, the bearing receiving portion 121b of the driven shaft 120 is held in a state where it abuts against the inner race 131b of the bearing 131. The axial load LDsp of the coil spring 142 is determined by the compressive force of the coil spring 142, and is therefore approximately constant regardless of the gear ratio TR, as shown in Figure 5.

[0071] Therefore, when the thrust load LD from the helical gear 127 becomes greater than the axial load LDsp from the coil spring 142, the driven shaft 120 moves to the right. In other words, in region A0 shown in Figure 5, the driven pulley 90 and the starting clutch 72, which are supported by the driven shaft 120, move together to the right with the driven shaft 120.

[0072] In this embodiment, the center line 80a of the groove in the drive pulley 80 and the center line 90a of the groove in the driven pulley 90 are set to coincide when the top ratio is reached, that is, when the winding diameter of the drive pulley 80 is at its maximum and the winding diameter of the driven pulley 90 is at its minimum. Therefore, when the torque is close to a low torque T1, the gear ratio TR tends to become smaller, and the center line 80a of the groove in the drive pulley 80 and the center line 90a of the groove in the driven pulley 90 tend to coincide.

[0073] On the other hand, in the case of torque close to high torque T3, when the ratio is low, that is, when the winding diameter of the drive pulley 80 is at its minimum and the winding diameter of the driven pulley 90 is at its maximum, the movable sheave 82 of the drive pulley 80 moves to the right and the movable sheave 93 of the driven pulley 90 moves to the left. As a result, a positional misalignment of a displacement amount δ (see Figure 3) is likely to occur between the center line 80a of the groove width of the drive pulley 80 and the center line 90a of the groove width of the driven pulley 90.

[0074] In contrast, in this embodiment, when the torque is close to a high torque T3 where a displacement δ is likely to occur, the driven shaft 120 can be moved to the right by utilizing the reaction force of the driving force, that is, the thrust force due to the meshing of the helical gear 127 and the first gear 151, and the driven pulley 90 supported by the driven shaft 120 can also be moved to the right. Therefore, the displacement δ between the center line 80a of the groove of the drive pulley 80 and the center line 90a of the groove of the driven pulley 90 is easily suppressed. Consequently, the load on the side of the V-belt 100 is suppressed, and friction loss during the transmission of driving force is easily suppressed.

[0075] As described above, according to the first embodiment to which the present invention is applied, a V-belt type transmission 71 is provided with a drive pulley 80 provided on a crankshaft 32, a driven pulley 90 provided on a driven shaft 120, and a V-belt 100 wrapped between the drive pulley 80 and the driven pulley 90, and stepless speed changes are performed by changing the winding radius of the V-belt 100 between the drive pulley 80 and the driven pulley 90. The transmission has a misalignment adjustment mechanism 140 that moves the driven pulley 90 in the axial direction by the reaction force of the driving force, thereby reducing the amount of misalignment δ between the center line 80a of the groove of the drive pulley 80 and the center line 90a of the groove of the driven pulley 90. With this configuration, when a large driving force is generated, the reaction force of the driving force can be used to reduce the amount of misalignment δ between the center line 80a of the groove in the drive pulley 80 and the center line 90a of the groove in the driven pulley 90 in the V-belt type transmission 71, thereby reducing friction loss in the V-belt 100.

[0076] In this embodiment, the driven shaft 120 is provided with a starting clutch 72, and the misalignment adjustment mechanism 140 moves the driven pulley 90 and the starting clutch 72 together. With this configuration, the driven pulley 90 and the starting clutch 72, which are driven to rotate by the V-belt 100, are moved axially as a single unit, making it easier to improve the response of the misalignment adjustment mechanism 140 during operation. Furthermore, with this configuration, since the driven pulley 90 and the starting clutch 72 are integrated as a unit, the assembly of the V-belt type transmission 71 is made easier.

[0077] Furthermore, in this embodiment, the displacement adjustment mechanism 140 has a coil spring 142 on the axial side, which is the right side in the axial direction, and the driven shaft 120 is always biased to the left side in the axial direction (a predetermined axial direction) by the coil spring 142. This configuration makes it possible to reduce the occurrence of play in the driven shaft 120 when large driving forces are generated intermittently.

[0078] Furthermore, in this embodiment, the misalignment adjustment mechanism 140 includes a helical gear 127 provided on the driven shaft 120, and the thrust force generated in the helical gear 127 during driving moves the driven pulley 90 in the axial direction. This configuration allows for the generation of axial thrust to adjust the amount of displacement δ without the need for a new drive mechanism.

[0079] Furthermore, in this embodiment, a bearing 133 is provided to rotatably support the driven shaft 120, and the coil spring 142 of the misalignment adjustment mechanism 140 is supported between the inner race 133b of the bearing 133 and the driven shaft 120. With this configuration, the coil spring 142 and the driven shaft 120 rotate in sync, thereby suppressing friction between the driven shaft 120 and the coil spring 142.

[0080] Furthermore, in this embodiment, when the V-belt type transmission 71 is set to the gear ratio corresponding to the top gear, the center line 80a of the groove of the drive pulley 80 and the center line 90a of the groove of the driven pulley 90 are aligned. With this configuration, by aligning the centerlines 80a and 90a of the grooves between the drive pulley 80 and the driven pulley 90 based on the frequently used area and the area where the reaction force of the driving force is small, the centerlines 80a and 90a of the grooves between the drive pulley 80 and the driven pulley 90 in the V-belt type transmission 71 can be effectively aligned. Furthermore, with this configuration, the misalignment adjustment mechanism 140 can be activated in situations where a large driving force is generated, such as when starting.

[0081] [Second Embodiment] A second embodiment applying the present invention will now be described. In this second embodiment, parts configured in the same manner as in the first embodiment will be denoted by the same reference numerals and their description will be omitted.

[0082] Figure 6 shows the peripheral portion of the displacement adjustment mechanism 240 according to the second embodiment. Figure 6 corresponds to Figure 3 of the first embodiment. In the second embodiment, instead of the driven shaft 120 and the misalignment adjustment mechanism 140 of the first embodiment, there is a driven shaft (output shaft) 220 and a misalignment adjustment mechanism 240.

[0083] Specifically, the driven shaft 220 of the second embodiment differs from the driven shaft 120 of the first embodiment in that the spring housing portion 128a of the right end shaft portion 128 is omitted. The right end shaft portion 128 is loosely supported by the inner race 133b.

[0084] In the displacement adjustment mechanism 240, the spring seat 141 is omitted. The displacement adjustment mechanism 240 has a roughly annular disc spring (spring mechanism) 242 instead of a coil spring 142.

[0085] In the driven shaft 220, a disc spring 242 is positioned between the helical gear 127 and the bearing 133. The disc spring 242 is positioned between the helical gear 127 and the bearing 133 of the driven shaft 220 with the driven shaft 220 inserted through a hole in the radial center of the disc spring 242. The disc spring 242 biases the driven shaft 220 to the left.

[0086] In this embodiment, the disc spring 242 contacts only the side surface of the inner race 133b of the bearing 133. Specifically, the disc spring 242 is positioned between the helical gear 127 and the bearing 133 via a disc spring seat 241. The disc spring seat 241 is formed in an annular shape through which the driven shaft 220 is inserted. More specifically, the disc spring seat 241 has a base portion 241a that contacts only the side surface of the inner race 133b of the bearing 133, a connecting portion 241b that is connected to the radially outer end of the base portion 241a and extends in a direction away from the bearing 133, and a seat body portion 241c that extends radially outward from the radially outer end of the connecting portion 241b. The radially outer end of the disc spring 242 contacts the left surface of the seat body portion 241c.

[0087] In this embodiment, the misalignment adjustment mechanism 240 is composed of a driven shaft 220, a helical gear 127, a first gear 151, a disc spring seat 241, a disc spring 242, and bearings 131, 132, and 133.

[0088] In the second embodiment, as in the first embodiment, the thrust load LD of the helical gear 127 is used to make it easier to align the center line 90a of the groove width of the driven pulley 90 with the center line 80a of the groove width of the drive pulley 80.

[0089] In particular, in the second embodiment, the driven shaft 220 is constantly biased by the disc spring 242. Therefore, in the second embodiment, compared to the first embodiment, steps such as machining the spring housing portion 218a on the driven shaft 220 can be omitted. Thus, it is easier to suppress play in the driven shaft 220 while reusing a driven shaft of a shape that has been used conventionally.

[0090] As described above, in the second embodiment to which the present invention is applied, as in the first embodiment, when a large driving force is generated, the reaction force of the driving force can be used to reduce the amount of deviation δ between the center line 80a of the groove of the drive pulley 80 and the center line 90a of the groove of the driven pulley 90 in the V-belt type transmission 71, thereby reducing friction loss in the V-belt 100.

[0091] [Third Embodiment] A third embodiment to which the present invention is applied will now be described. In this third embodiment, parts configured in the same way as in the first embodiment described above are denoted by the same reference numerals and their description is omitted.

[0092] Figure 7 shows the peripheral portion of the displacement adjustment mechanism 340 according to the third embodiment. Figure 7 corresponds to Figure 3 of the first embodiment. In the third embodiment, the driven shaft 120 and the misalignment adjustment mechanism 140 of the first embodiment are replaced with a driven shaft (output shaft) 320 and a misalignment adjustment mechanism 340.

[0093] Specifically, the driven shaft 320 of the third embodiment differs from the driven shaft 120 of the first embodiment in that a gear support portion 321 is formed in place of the helical gear 127 and the bearing receiving portion 121b. The gear support portion 321 extends to the right with the same diameter as the bearing mounting portion 121. A cam portion 322 is formed at the right end of the gear support portion 321. The cam portion 322 protrudes radially outward from the outer circumferential surface of the driven shaft 320, i.e., the outer circumferential surface of the gear support portion 321. Multiple cam portions 322 are formed on the outer circumferential surface of the gear support portion 321, for example, at equal intervals in the circumferential direction.

[0094] A cylindrical gear member 327 extending in the axial direction is mounted on the gear support portion 321. The gear member 327 has a spur gear portion (reduction gear) 327a formed on its outer circumference, which extends in a groove-like manner in the axial direction. A cam groove 327b is formed on the inner circumference of the gear member 327, into which the cam portion 322 of the driven shaft 320 can engage. A bearing abutment portion 327c is formed at the left end (inner axial end) of the gear member 327. The bearing abutment portion 327c abuts against the inner race 131b of the bearing 131.

[0095] The driven shaft 320 is configured to generate a thrust force to the right when the cam portion 322 and the inner circumferential surface of the cam groove portion 322b come into contact. Specifically, for example, the cam portion 322 can be made into a rod shape, and the inner circumferential surface of the cam groove portion 322b can be made into a surface that inclins toward the front side in the rotational direction R as it moves to the right. As a result, when the cam portion 322 comes into contact with the inner circumferential surface of the cam groove portion 322b, a thrust force to the right is generated on the driven shaft 320. The cam mechanism 323 of this embodiment is formed by the cam portion 322 and the cam groove portion 322b.

[0096] In this embodiment, the misalignment adjustment mechanism 340 is comprised of a driven shaft 320, a cam mechanism 323, a gear member 327, a first gear 151, a spring seat 141, a coil spring 142, and bearings 131, 132, and 133.

[0097] In the third embodiment, when the driving force is applied by the cam mechanism 323, a thrust load LD acts on the driven shaft 320 as a reaction force. Therefore, in the third embodiment, as in the first embodiment, the thrust load LD is used to easily align the center line 90a of the groove width of the driven pulley 90 with the center line 80a of the groove width of the drive pulley 80.

[0098] As described above, in the third embodiment to which the present invention is applied, as in the first embodiment, when a large driving force is generated, the amount of deviation δ between the center line 80a of the groove of the drive pulley 80 and the center line 90a of the groove of the driven pulley 90 in the V-belt type transmission 71 can be reduced by using the reaction force of the driving force, thereby reducing friction loss generated in the V-belt 100.

[0099] In particular, in this embodiment, the misalignment adjustment mechanism 340 comprises a spur gear portion 327a arranged coaxially with the driven shaft 320, and a cam mechanism 323 provided between the driven shaft 320 and the spur gear portion 327a, and the cam mechanism 323 moves the driven pulley 90 in the axial direction by the reaction force of the driving force. This configuration allows for greater flexibility in setting the torsional angle of the helical gear. Specifically, if the torsional angle of the helical gear makes it difficult to obtain a thrust load LD that moves the driven pulley 90 axially, the cam mechanism 323 can be provided to make it easier to move the driven pulley 90 axially.

[0100] [Other embodiments] The embodiments described above represent only one aspect of the present invention and can be modified and applied as needed without departing from the spirit of the invention.

[0101] In the above embodiment, a configuration was described in which the driven pulley 90 can move integrally with the driven shafts 120, 220, and 320. However, a configuration in which only the driven pulley 90 moves in the axial direction to suppress the amount of displacement δ is also possible.

[0102] In the third embodiment described above, a configuration using the spur gear section 327a when a cam mechanism 323 is provided was described, but a helical gear 127 may also be used.

[0103] In the above embodiment, a motorcycle having a front wheel 13 and a rear wheel 15 was used as an example to describe the saddle-type vehicle 10. However, the present invention is not limited thereto, and can be applied to three-wheeled saddle-type vehicles having two front or rear wheels, or saddle-type vehicles having four or more wheels.

[0104] [Configurations supported by the above embodiment] The above embodiment supports the following configuration.

[0105] (Configuration 1) A continuously variable transmission comprising a drive pulley provided on an input shaft, a driven pulley provided on an output shaft, and a transmission member wrapped between the drive pulley and the driven pulley, wherein stepless speed changes are performed by changing the wrapping radius of the transmission member between the drive pulley and the driven pulley, and the continuously variable transmission is characterized by having a misalignment adjustment mechanism that reduces the amount of misalignment between the center line of the groove of the drive pulley and the center line of the groove of the driven pulley by moving the driven pulley in the axial direction due to the reaction force of the driving force. With this configuration, when a large driving force is generated, the reaction force of the driving force can be used to reduce the amount of misalignment between the center line of the groove of the drive pulley and the center line of the groove of the driven pulley in the continuously variable transmission, thereby reducing friction loss in the transmission members.

[0106] (Configuration 2) The continuously variable transmission according to Configuration 1, wherein the output shaft is provided with a centrifugal clutch, and the misalignment adjustment mechanism moves the driven pulley and the centrifugal clutch together. This configuration allows for the driven pulley and centrifugal clutch, which are driven to rotate by the transmission member, to move axially as a single unit, thereby improving the response of the misalignment adjustment mechanism. Furthermore, because the driven pulley and centrifugal clutch are integrated as a unit in this configuration, the assembly of the continuously variable transmission is made easier.

[0107] (Configuration 3) The continuously variable transmission according to Configuration 1 or 2, characterized in that the deviation amount adjustment mechanism has a spring mechanism on one axial side, and the output shaft is always biased in a predetermined axial direction by the spring mechanism. This configuration makes it possible to reduce the occurrence of play in the output shaft when large driving forces are generated intermittently.

[0108] (Configuration 4) The continuously variable transmission according to any one of Configurations 1 to 3, characterized in that the deviation adjustment mechanism comprises a helical gear provided on the output shaft, and the driven pulley is moved in the axial direction by the thrust force generated on the helical gear during driving. This configuration allows for the generation of axial thrust to adjust the amount of misalignment without the need for a new drive mechanism.

[0109] (Configuration 5) The continuously variable transmission according to any one of Configurations 1 to 3, wherein the deviation adjustment mechanism comprises a reduction gear arranged coaxially with the output shaft and a cam mechanism provided between the output shaft and the reduction gear, and the cam mechanism moves the driven pulley in the axial direction by the reaction force of the driving force. This configuration allows for greater flexibility in setting the torsional angle of the helical gear.

[0110] (Configuration 6) The continuously variable transmission according to Configuration 3, comprising a bearing that rotatably supports the output shaft, wherein the spring mechanism of the misalignment adjustment mechanism is supported between the inner race of the bearing and the output shaft. With this configuration, the spring mechanism and the output shaft rotate in sync, which suppresses friction between the output shaft and the spring mechanism.

[0111] (Configuration 7) The continuously variable transmission according to any one of Configurations 1 to 6, characterized in that, in the case of the gear ratio corresponding to the top gear, the center line of the groove of the drive pulley and the center line of the groove of the driven pulley are aligned. This configuration allows for effective alignment of the grooves between the drive pulley and the driven pulley in a continuously variable transmission by aligning the centerlines of the grooves between the drive pulley and the driven pulley based on a frequently used area with low reaction force. Furthermore, this configuration allows the misalignment adjustment mechanism to be activated in situations where large driving forces are generated, such as during starting. [Explanation of symbols]

[0112] 32 Crankshaft (Input Shaft) 71 V-belt type transmission (continuously variable transmission) 72. Starting clutch (centrifugal clutch) 80 Drive pulley 80a center line 90 Driven pulley 90a center line 100 V belt (transmission component) 120 Driven shaft (output shaft) 127 Helical Gear 133 Bearings 133b Inner Lace 140. Mechanism for adjusting the amount of deviation 142 Coil spring (spring mechanism) 220 Driven shaft (output shaft) 240 Misalignment adjustment mechanism 242 Disc spring (spring mechanism) 320 Driven shaft (output shaft) 323 Cam mechanism 327a Spur gear section (reduction gear) 340 Misalignment adjustment mechanism

Claims

1. In a continuously variable transmission (CVT) comprising a drive pulley (80) provided on an input shaft (32), driven pulleys (90) provided on output shafts (120, 220, 320), and a transmission member (100) wrapped between the drive pulley (80) and the driven pulley (90), where stepless speed changes are performed by changing the winding radius of the transmission member (100) between the drive pulley (80) and the driven pulley (90), The device has a misalignment adjustment mechanism (140, 240, 340) that reduces the amount of misalignment (δ) between the center line (80a) of the groove of the drive pulley (80) and the center line (90a) of the groove of the drive pulley (90) by moving the driven pulley (90) in the axial direction due to the reaction force of the driving force. A continuously variable transmission characterized by the following features.

2. The output shafts (120, 220, 320) are provided with centrifugal clutches (72). The aforementioned displacement adjustment mechanism (140, 240, 340) moves the driven pulley (90) and the centrifugal clutch (72) together. The continuously variable transmission according to feature 1.

3. The aforementioned misalignment adjustment mechanism (140, 240, 340) has a spring mechanism (142, 242) on one axial side, and the spring mechanism (142, 242) constantly biases the output shaft (120, 220, 320) in a predetermined axial direction. The continuously variable transmission according to feature 2.

4. The aforementioned misalignment adjustment mechanism (140, 240) includes a helical gear (127) provided on the output shaft (120, 220), and moves the driven pulley (90) in the axial direction by the thrust force generated on the helical gear (127) during operation. The continuously variable transmission according to feature 3.

5. The deviation adjustment mechanism (340) comprises a reduction gear (327a) arranged coaxially with the output shaft (320), and a cam mechanism (323) provided between the output shaft (320) and the reduction gear (327a). The reaction force of the driving force causes the driven pulley (90) to move in the axial direction by the cam mechanism (323). The continuously variable transmission according to feature 3.

6. The output shafts (120, 220, 320) are rotatably supported by bearings (133), The spring mechanism (142, 242) of the displacement adjustment mechanism (140, 240, 340) is supported between the inner race (133b) of the bearing (133) and the output shaft (120, 220, 320). The continuously variable transmission according to feature 3.

7. In the continuously variable transmission (71), when the gear ratio corresponds to the top gear, the center line (80a) of the groove in the drive pulley (80) and the center line (90a) of the groove in the driven pulley (90) are aligned. The continuously variable transmission according to feature 1.

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