JP2009168080A - Driven-side pulley for v-belt type automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driven-side pulley for a V-belt type automatic transmission which realizes smooth automatic speed change at reacceleration by applying appropriate thrust corresponding to engine torque to a movable pulley. <P>SOLUTION: A driven-side pulley for a V-belt type automatic transmission consists of a driven shaft 3, a fixed pulley half 1 having a fixed boss 12 keeping a cam pin 13 on the outer periphery, a movable pulley half 2 having a movable boss 22 keeping a cam groove 23 therein, a clutch part 4 rotating together with the fixed pulley half 1 and a torsion coil spring 5. The cam groove 23 is formed in a direction of inclination gradually approaching the movable pulley phase 21 side along a rotational direction of the movable boss 22. The fixed boss 12 is inserted into the movable boss 22. The cam pin 13 is inserted into a cam groove 23. The torsion coil spring 5 keeps one end in a longitudinal direction and the other end locked and fixed to the fixed pulley half 2 and to the clutch part 4, respectively, in a state of having an elastic restoration force in advance by applying torsion in a winding direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a driven pulley of a V-belt type automatic transmission that provides an appropriate thrust corresponding to an engine torque to a movable pulley and realizes a smooth automatic shift at the time of reacceleration.

In general, the driven pulley of the V-belt type automatic transmission includes a mechanism (torque cam mechanism) that changes a part of the belt transmission force to a pressing force in the axial direction by the driven movable pulley side cam and the fixed pulley side pin. There is a V-belt type automatic transmission (CVT), and Patent Document 1 discloses a mechanism that fixes both ends of a thrust spring (coil spring) to a clutch plate and a movable pulley.
Japanese Patent Laid-Open No. 5-60192

  In Patent Document 1, when the reduction ratio shifts from the high speed range state (TOP) to the low speed range state (LOW), the driven pulley has a restoring force in the rotational direction of the torsion coil spring, and a cam on the movable pulley side. The axial pressing force due to the engagement with the pin on the fixed pulley side becomes a biasing force to the force (thrust) for moving the movable pulley relative to the fixed pulley. The cam is a slot with a long hole formed in the boss portion of the movable pulley and inclined with respect to the axial direction of the boss portion. In the process of shifting from the high-speed region state to the low-speed region state, in the high-speed region state, the movable pulley rotates relative to the fixed pulley, and the pin on the fixed pulley side is the cam side surface of the groove shape on the movable pulley side ( Abutting and pressing the inner peripheral surface).

  When shifting from the high speed region state to the low speed region state, the movable pulley moves to the fixed pulley side by the axial pressing force of the spring. At this time, on the cam side surface (inner peripheral surface) on the movable pulley side, the component force of the force F inclined in the axial direction received from the pin on the fixed pulley side is the force along the axial direction of the boss portion, that is, the axial direction. The force Fx is a force that moves the movable pulley toward the fixed pulley (see FIG. 8C).

  In the low speed range state, both ends of the coil spring are fixed to the clutch plate and the movable pulley, respectively, and when the transition from the low speed range state to the high speed range state, the movable pulley is relative to the fixed pulley and the clutch plate. By rotating, the restoring force of torsion is stored in the coil spring, and this restoring force works in the same rotational direction as the movable pulley in the transition operation from the high speed state to the low speed state, and the thrust of the movable pulley by the action of the cam Become an urging force.

  The prior art disclosed in Patent Document 1 has the following problems. First, there are various examples of the shape of the cam 100a on the movable pulley side, and a linear shape that is inclined in the axial direction of the boss portion of the movable pulley 100, or a curve (arc) shape that is similarly inclined in the axial direction. Or in the form of a broken line. In these examples, the axial force Fx is very small with respect to F (see FIG. 8C). Therefore, in the cam 100a having the shape of the above example, the thrust of the movable pulley 100 tends to be insufficient, and the shortage needs to be compensated by adding a pressing force in the compression direction of the coil spring 200. However, since the pressing force in the compression direction of the coil spring 200 is constant regardless of the engine torque, the pressing force has an unnecessary portion with respect to the engine torque, which includes friction loss, friction between the belt and the pulley. This may cause problems such as aging due to compression and tension of the belt rubber.

  Further, the width of the V-belt 7300 decreases after the V-belt 300 is worn, and the belt winding diameter is reduced on the driving side (see FIG. 8C). Therefore, the belt winding diameter increases on the driven side, and at this time, the movable pulley approaches the fixed pulley, and as a result, the installation state of the torsion coil spring also changes.

  When the width of the V-belt 300 is reduced due to wear, the pulley distance in the driving pulley mechanism 500 is not narrowed, so the diameter of the V-belt in contact with the pulley is reduced. Accordingly, the pulley on the driven side is narrowed by the axial pressing force (compression direction) of the spring, and the V-belt diameter is increased (see FIG. 8B). That is, the cam of the driven pulley on the driven side is further rotated to the fixed pulley side. At the time of transition from the high speed range state to the low speed range state, the force in the torsional direction of the spring becomes 0 (zero) at the position of the movable pulley 100 in the low speed range state before the belt wear.

  Therefore, within the clearance width, the movable pulley rotates in the direction opposite to the direction in which the elastic restoring force is stored, so that the spring spreads in the direction opposite to the torsion and the negative restoring force is accumulated. Accordingly, there arises a disadvantage that the transmission capability of the driven pulley is lowered at the time of shifting to the low speed range state after deceleration. An object of the present invention is to realize a smooth automatic shift at the time of reacceleration, suppress a decrease in reacceleration, and provide a movable pulley with an appropriate thrust corresponding to an engine torque in a driven pulley. It is to provide an automatic transmission.

  Therefore, as a result of earnest and research in order to solve the above problems, the inventor devised the invention of claim 1 as a driven shaft, and a fixed pulley half having a fixed boss portion with a cam pin formed on the outer periphery, A movable pulley half having a movable boss portion formed with a cam groove, a clutch portion that rotates together with the fixed pulley half, and a torsion coil spring, and the cam groove along the rotational direction of the movable boss portion The fixed boss portion is inserted into the movable boss portion, the cam pin is inserted into the cam groove, and the torsion coil spring is twisted in the winding direction. In the state where the elastic belt has an elastic restoring force in advance, one end in the longitudinal direction is fixed to the movable pulley half and the other end is locked and fixed to the clutch portion. By a was, the above-mentioned problems are eliminated.

  According to a second aspect of the present invention, in the configuration described above, the cam groove has a steep slope closer to the diameter direction of the movable boss portion with respect to the axial direction of the movable boss portion. By using a pulley, the above problems were solved. According to a third aspect of the present invention, in the configuration described above, the cam groove has a steep slope closer to the diameter direction of the movable boss portion with respect to the axial direction in a region close to the movable pulley face side, and the movable pulley face side The above-mentioned problem has been solved by employing a driven pulley of the V-belt type automatic transmission in which the movable boss portion has a gentle inclination toward the axial direction in a region away from the center.

  According to a fourth aspect of the present invention, in the above-described configuration, the steeply inclined region and the gently inclined region of the cam groove are driven pulleys of a V-belt type automatic transmission having a substantially polygonal line shape. did. According to a fifth aspect of the present invention, in the above-described configuration, the cam groove is a driven pulley of a V-belt type automatic transmission in which the steeply inclined region and the gently inclined region are continuously formed in a substantially arc shape. The above problem has been solved.

  In the invention of claim 1, the torsion coil spring is twisted in the winding direction of the coil, and the torsion coil spring of the torsion coil spring is in a low speed region state or a stop state in which the stationary pulley half and the movable pulley half are closest to each other. One end in the longitudinal direction is locked and fixed to the movable pulley half, and the other end is fixed to the clutch portion. As a result, the movable pulley half moves closer to the fixed pulley half, so that when the transition from the high speed state to the low speed state occurs, the torsion coil spring of the movable pulley half It is possible to suppress a reduction in restoring force generated in the rotation direction and to prevent a decrease in reacceleration performance.

  The above effect will be described in detail. In the high-velocity state before V-belt wear, that is, in the state where the movable pulley half is separated from the fixed pulley half, the torsion coil spring has both elasticity in the winding direction and compression by the coil compression. Energy is accumulated, and an elastic restoring force is generated in the same direction as the rotation direction of the movable pulley half. Thus, by adding the elastic restoring force due to the normal twisting of the torsion coil spring generated by the movable pulley half in the high-speed region state and the elastic restoring force of the initial torsion setting due to the previously added torsion, the torsion coil spring Thus, the movable pulley half is rapidly moved to the fixed pulley half.

  Furthermore, after the V-belt is worn and thinned in the width direction, when the movable pulley half reaches the clearance area in the proximity movement with the fixed pulley half, the torsion coil spring is movable according to the initial torsion setting. A decrease in the elastic biasing force in the rotational direction of the pulley half can be suppressed, and the movable pulley half can be reliably moved toward the fixed pulley half in the escape region. When the driven pulley transitions from the high speed region state to the low speed region state, the diameter of the V-belt wrap around the driven pulley increases, and the movable pulley half reaches the escape region, and further moves toward the fixed pulley half. In some cases, the distance between the stationary pulley half and the movable pulley half must be reduced. Therefore, in consideration of further wear in the width direction of the V-belt, a relief area is set in advance between the fixed pulley half and the movable pulley half.

  At this time, the moving operation of the movable pulley half in the relief region has an elastic restoring force accumulated by a twist applied in advance in the coil winding direction of the torsion coil spring. Even if the wear in the width direction sufficiently progresses, it is possible to sufficiently compensate for the deterioration of the elastic restoring force of the torsion coil spring from the high speed range state to the low speed range state and to prevent the reacceleration performance from being lowered.

  According to the invention of claim 2, the cam groove has a steep slope in the axial direction of the movable boss portion with respect to the axial direction of the movable boss portion. The first contact surface with the cam groove is close to the direction along the rotational direction of the movable boss, so that the cam groove receives the force component from the cam pin, that is, the movable pulley half moves toward the fixed pulley half. The axial force to be moved can be further increased, sufficiently assisting the elastic restoring force of the torsion coil spring, and the movable pulley half can be moved toward the fixed pulley half so that it can move from the high speed range to the low speed range. Transition in the state can be performed very smoothly.

  According to a third aspect of the present invention, the cam groove has a steep slope closer to the diameter direction of the movable boss portion with respect to the axial direction in a region close to the movable pulley half, and in a region away from the movable pulley half. Since the movable boss portion has a gentle inclination toward the axial direction, the transition from the high speed range state to the low speed range state is performed quickly, and unnecessary biasing of the force to the cam is prevented. An excessive pressing force can be avoided, and the acceleration performance during re-acceleration is improved.

  The above effects are described below. When the movable pulley half rotates relative to the fixed pulley half, the belt tension at which the V-belt rotates the driven pulley varies from the low speed range (LOW) to the medium speed range (MID), and further to the medium speed. It changes with the transition from the high speed range state (TOP) to the high speed range state, and particularly decreases from the medium speed range state to the high speed range state. In the region close to the movable pulley half, the cam groove has a steep slope closer to the diametrical direction in the axial direction of the movable boss portion. Can be larger than the conventional one. In addition, in the region away from the movable pulley half, the gentle inclination in the axial direction of the movable pulley makes the transition from the middle speed range state to the low speed range state, and the cam groove receives the force from the cam pin. It can prevent becoming larger than the conventional one. Therefore, it is possible to prevent unnecessary belt pressing force from being generated on the driven pulley, and it is possible to prevent belt friction loss, friction with the pulley, rubber compression, aging, and the like.

  According to the fourth aspect of the present invention, the steeply inclined region and the gently inclined region of the cam groove are formed in a substantially polygonal line shape, so that the transition from the high speed region state to the medium speed region state can be performed quickly. The re-acceleration can be improved. According to the invention of claim 5, the transition between the high speed range state, the medium speed range state, and the low speed range state can be performed continuously and smoothly, and the impact accompanying the change in each shift range can be mitigated.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 shows a driven pulley mechanism according to the present invention. The driven pulley mechanism is mainly composed of a fixed pulley half 1, a movable pulley half 2, a clutch part 4 and a torsion coil spring 5, as shown in FIGS. Composed. The fixed pulley half 1 includes a flat conical fixed pulley face 11, a hollow fixed boss portion 12, and a cam pin 13. A cam pin 13 is attached to the fixed boss portion 12. Next, the movable pulley half 2 includes a flat conical movable pulley face 21, a hollow movable boss portion 22, and a cam groove 23. The cam groove 23 is inclined so as to be close to the movable pulley face side along the rotational direction of the movable boss portion 22.

  As shown in FIGS. 3C, 5B, and 5C, the cam groove 23 is formed so as to be steeply inclined in the axial direction of the movable boss portion 22. Specifically, it is formed as a steep slope close to the diameter direction of the movable boss portion 22. In particular, the region at a position close to the movable pulley face 21 side of the movable pulley half 2 is referred to as a steeply inclined region portion 231 formed as a steeply inclined shape close to the diameter direction of the movable boss portion 22. Further, the region of the movable pulley half 2 that is located away from the movable pulley face 21 is referred to as a gently inclined region portion 232 formed as a gently inclined portion in the axial direction of the movable boss portion 22. Here, the steep inclination angle is about 45 degrees or more with respect to the axial direction of the movable boss portion 22. The gentle inclination angle is about 40 degrees or less with respect to the axial direction of the movable boss portion 22.

  In the cam groove 23, there is an embodiment in which the steeply inclined region portion 231 and the gently inclined region portion 232 are formed in a substantially broken line shape as continuous long holes. In this embodiment, the steeply inclined region portion 231 and the gently inclined region portion 232 have a substantially “<” shape or a substantially “H” shape (see FIGS. 5A and 5B). Here, the gently inclined region 232 is formed shorter than the steeply inclined region 231. In addition, there is an embodiment in which the steeply inclined region portion 231 and the gently inclined region portion 232 are continuously formed in a substantially arc shape [see FIG. 5C]. In this case, both the steeply inclined region portion 231 and the gently inclined region portion 232 are arcuately curved in the same direction, and the boundary between the steeply inclined region portion 231 and the gently inclined region portion 232 is connected in an arcuate shape. There is also an embodiment in which the cam groove 23 is formed only by the steeply inclined region portion 231 that is entirely linear.

  The fixed boss 12 of the fixed pulley half 1 is rotatably supported on the driven shaft 3 as shown in FIG. Specifically, the fixed boss portion 12 of the fixed pulley half 1 is rotatably supported on the driven shaft 3 via a bearing such as a needle bearing and a ball bearing. The fixed boss portion 12 is inserted into the movable boss portion 22 so that the axial directions thereof coincide with each other, and the movable pulley half 2 is slidable with respect to the fixed pulley half 1 and is rotatable relative to each other. The movable pulley face 21 moves toward and away from the face 11 so that the distance between the two is freely adjustable. Further, a relief region S is provided in advance between the fixed pulley half 1 and the movable pulley half 2.

  The clearance portion region S means that when the V-belt 7 is worn in the width direction and the dimension in the width direction is shortened, the V-belt 7 is pressed with a good pressure between the fixed pulley face 11 and the movable pulley face 21. This is a region in which the movable pulley half 2 can move to the fixed pulley half 1 side for clamping (see FIGS. 1 and 3A). The escape region S is a region where the movable pulley face 21 does not enter when the V-belt 7 is not worn or during a period in which the reduction in the width dimension due to wear is small. The cam pin 13 of the fixed boss portion 12 is inserted into the cam groove 23 of the movable boss portion 22, and the movable pulley half 2 is within the length of the cam groove 23 based on the cam pin 13 and the cam groove 23. Thus, while rotating relatively to the fixed pulley half 1, the shaft moves in the axial direction so as to approach and separate from the fixed pulley half 1. This relief portion region S also exists in the cam groove 23, and is a region where the cam pin 13 moves when the V belt 7 is worn in the width direction and the width direction dimension is shortened.

  The clutch portion 4 is mounted on the other end side of the fixed boss portion 12 of the driven pulley (see FIG. 6). The clutch portion 4 includes a clutch plate 41, a clutch weight 42, a support plate 43, a clutch outer 44, and the like. A plurality of clutch weights 42, 42,... Are pivotally connected to the clutch plate 41 by the same number of pivot pins 45. The clutch outer 44 is fixed to the shaft end portion of the driven shaft 3. The clutch plate 41 is fixed to the shaft end portion of the fixed boss portion 12. The rotational force transmitted to the fixed pulley half 1 is transmitted to the clutch plate 41 through the fixed boss portion 12, and then the clutch weights 42, 42, ... are applied to the inner peripheral side surface of the clutch outer 44 by centrifugal force. Abutting, and rotational force is transmitted from the clutch outer 44 to the driven shaft 3.

  A pivot plate 45, 45,... Mounted on the clutch plate 41 is mounted with a support plate 43 so as to cover the clutch weights 42, 42,. FIG. 7). The support plate 43 is fixed to the tips of pivot pins 45, 45,... Mounted on the clutch plate 4 by a retaining ring such as a circlip or caulking. The support plate 43 serves to support the clutch weights 42, 42,... Mounted on the clutch plate 41.

  A through hole 43a is formed at the center of the support plate 43, and a spring support portion 43b is formed around the through hole 43a. As shown in FIG. 7 (B), the spring support portion 43b is formed to bulge out toward the clutch plate 41 so as to have a substantially cylindrical shape, and the coiled portion 51 of the torsion coil spring 5 is formed. Enclose a part of. The clutch outer 44 has a substantially cup shape as shown in FIG. The outer periphery of the clutch outer 44 has a substantially cylindrical shape, and the lining attached to the swinging clutch weights 42, 42,.

  A torsion coil spring 5 is mounted between the back side of the movable pulley face 21 of the movable pulley half 2 and the clutch plate 41 or the support plate 43 of the clutch portion 4. Specifically, the cover member 6 is disposed on the back side of the movable pulley face 21 and between the movable boss portion 22, and the torsion coil spring 5 is attached via the cover member 6. As shown in FIGS. 2A and 2B, the helical coil spring 5 has hook portions 52 and 52 formed at both ends in the longitudinal direction of the coil-like portion 51.

  The hook portion 52 is formed as a shaft piece that is bent substantially in the vicinity of the end portion of the wire constituting the coil-shaped portion 51 and becomes a substantially straight shaft. The hook portion 52 that is the shaft piece is formed of the coil-shaped portion 51. It is formed in the same direction as the expansion / contraction direction (longitudinal direction). The hook portion 52 is formed at both ends of the coiled portion 51 in the expansion / contraction direction (longitudinal direction). The cover member 6 has a spring receiving portion 62 formed on one end side in the longitudinal direction of the cylindrical portion 61, and the spring receiving portion 62 extends in the diametrical direction of the cylindrical portion 61. Is formed.

  As shown in FIG. 6, the torsion coil spring 5 is disposed on the outer peripheral side of the cover member 6, and one end side of the coiled portion 51 abuts on the clutch plate 41 or the support plate 43 of the clutch portion 4. The hook portion 52 on one end side is locked and fixed to a locked portion 46 such as a through hole formed in the clutch plate 41 or the support plate 43. The other end in the longitudinal direction of the torsion coil spring 5 is in contact with the spring receiving portion 62 of the cover member 6, and the hook portion 32 on the other end side is the movable boss portion 22 or the movable pulley face of the movable pulley half 2. It is locked and fixed to the locked portion 24 formed in 21.

  The torsion coil spring 5 elastically biases the movable pulley half 2 so as to approach the fixed pulley half 1 and rotates the movable pulley half 2 in the same direction as the rotation direction thereof. It plays the role of elastically energizing. Here, the rotation direction of the movable pulley half 2 is the same as the rotation direction of the driven shaft 3 and is the rotation direction when the rotation transmission is received by the driving pulley and the V belt 7. This rotational direction is a direction corresponding to the direction in which the two-wheeled vehicle moves forward. A V-belt 7 is wound between the fixed pulley face 11 of the fixed pulley half 1 and the movable pulley face 21 of the movable pulley half 2, and the driven pulley is driven by the driving pulley and the V belt 7. Rotation is transmitted.

  Next, the operation of the torsion coil spring 5 and the cam groove 23 (including the cam pin 13) in the present invention will be described with reference to FIG. In FIG. 4, a is a stop (fixed) position before wear of the V belt 7 in the low speed range (LOW), b is a stop (fixed) position after wear of the V belt 7 in the low speed range (LOW), and C is a high speed. The stop (fixed) position in the region state (TOP), d is the fixed position of the torsion coil spring 5 on the clutch unit 4 side.

  The process of generating a biasing force with respect to the thrust of the torsion coil spring 5 to the movable pulley half 2 will be described. First, in FIG. 4A, the process shifts from the high speed range state (TOP) to the low speed range state (LOW). The movable pulley half 2 is at a position in the low speed region before the V-belt 7 is worn, and the elastic restoring force F1 due to the torsion received from the movable pulley half 2 is 0, but the elastic restoring force F2 due to the initial torsion setting T is The force applied before installation does not become zero. Therefore, if the wear of the V-belt 7 is within the range of the relief region S of the cam groove 23, the negative restoring force is not stored because it rotates by the elastic restoring force F2. Next, in the transition from the low speed region state (LOW) to the high speed region state (TOP) in FIG. 4B, a positive elastic restoring force F1 + F2 is stored. Next, in the transition from the high speed region state (TOP) to the low speed region state (LOW) in FIG. 4C, the elastic restoring force in the rotational direction of the movable pulley half 2 becomes F1 + F2, and the thrust of the movable pulley is reduced. Reduces the biasing force.

  Hereinafter, the operation of the torsion coil spring 5 will be described in detail. When the torsion coil spring 5 is attached to the driven pulley, the twisted coil spring 51 is preliminarily twisted in the winding direction. A state where the twist is applied in the winding direction of the torsion coil spring 5 is referred to as an initial twist setting T. The twist direction in the initial twist setting T is opposite to the rotation direction of the driven shaft 3 (and the fixed pulley half 1 and the movable pulley half 2). That is, the elastic restoring force is made to be in the same direction as the rotational direction of the driven shaft 3 (and the fixed pulley half 1 and the movable pulley half 2) by twisting with the initial twist setting T.

  The torsion angle θ of the torsion coil spring 5 by this initial torsion setting T is such that the V belt 7 further has a width from the proximity of the fixed pulley face 11 of the fixed pulley half 1 and the movable pulley face 21 of the movable pulley half 2. It is determined in consideration of the relief region S where the movable pulley half 2 moves to the fixed pulley half 1 side by being worn in the direction. That is, the elastic restoring force that allows the movable pulley half 2 to move the relief region S toward the fixed pulley half 1 is accumulated in the torsion coil spring 5. The specific twist angle θ for that is about 30 to 45 degrees.

  By assembling the torsion coil spring 5 to which the initial torsion setting T is added to the movable pulley half 2 and the clutch plate 41 or the support plate 43 of the clutch portion 4, the torsion coil spring 5 has a low-speed region state or a stopped state. However, it has an elastic restoring force F2 that rotates in the same direction as the rotational direction of the driven shaft 3. When shifting from the low speed range state to the high speed range state, the movable pulley half 2 rotates relative to the fixed pulley half 1, and the torsion coil spring 5 stores a torsional restoring force F1. .

  Further, since the elastic restoring force F2 due to the initial torsion setting T is stored in the torsion coil spring 5, the elastic restoring force F2 is rotated when the movable pulley half body 2 rotates at the time of transition from the low speed region state to the high speed region state. The sum of two torsional restoring forces added to the torsion coil spring 5 by adding F1, that is, restoring force (F1 + F2) is stored, and even if the V-belt 7 becomes thin due to wear in the width direction. The decrease in the elastic biasing force in the rotational direction of the movable pulley half 2 can be suppressed.

  Further, the wear in the width direction of the V-belt 7 progresses and becomes thin, and when the stationary pulley half 1 and the movable pulley half 2 are in the normal proximity state in the low-speed region, sufficient friction pressure is applied to the V-belt 7. When it cannot be applied, the movement of the movable pulley half 2 reaches the escape region S. In this case, the restoring force F2 due to torsion of the torsion coil spring 5 in the low speed region state of the V-belt 7 before being worn is 0 (zero) in the normal proximity state between the fixed pulley half 1 and the movable pulley half 2. Thus, the movable pulley half 2 cannot move close to the fixed pulley half 1 in the escape region S, but is stored in advance in the torsion coil spring 5 by the initial twist setting T. The restoring force F1 is present, and the movable pulley half 2 can move close to the fixed pulley half 1 side in the escape region S by the restoring force F1.

  Next, the cam pin 13 and the cam groove 23 are formed as steep slopes in the diameter direction of the movable boss portion 22 with respect to the axial direction of the movable boss portion 22 of the movable pulley half 2. In the process of moving the movable pulley half 2 close to the fixed pulley half 1, the surface where the cam pin 13 and the cam groove 23 first contact each other is close to the direction along the rotational direction of the movable boss portion 22. Thus, the component force of the cam groove 23 received from the cam pin 13, that is, the force for moving the movable pulley half 2 toward the fixed pulley half 1 can be increased, and the high speed state can be changed to the low speed state. Can be smoothly performed.

  By making the cam groove 23 a steeply inclined region portion 231 in a region close to the movable pulley half body and a gently inclined region portion 232 in a region away from the movable pulley half body 2, the high speed region state is changed to the low speed region state. Further, it is possible to prevent unnecessary force from being applied by the cam pin 13 and the cam groove 23 and to prevent the pressing force to the V belt 7 from becoming excessive. In addition, when the movable pulley half 2 rotates relative to the fixed pulley half 1, the force F by which the V-belt 7 rotates the driven pulley is changed from a low speed state to a medium speed range state (FL). It becomes smaller as each shifts from the speed range state to the high speed range state (FT) (see FIG. 5C).

  Therefore, in the cam groove 23, the region close to the movable pulley half 2 is a steeply inclined region portion 231, so that the cam groove 23 can receive from the cam pin 13 quickly. The force Fx can be made larger than before. Further, by making the region away from the movable pulley half 2 into the gently inclined region portion 232, the transition from the middle speed range state to the low speed range state is performed gradually, and the cam Fx received by the cam groove 23 from the cam pin 13 is conventionally. Can be prevented [see FIGS. 8B and 8C]. As described above, the transition from the high speed region state to the low speed region state is performed promptly, unnecessary force of the cam groove 23 and the cam pin 13 is prevented, and the pressing force to the V belt 7 becomes excessive. Can be avoided. Therefore, friction loss of the belt, friction with the pulley, rubber compression, aging, etc. can be prevented.

  In the embodiment of the present invention, the circumferential portion 43b of the clutch support plate 43b with respect to the coiled portion 51 of the torsion coil spring 5 causes the coiled portion 51 to have a diameter of the movable boss portion 22 due to centrifugal force when the driven pulley rotates. It is possible to prevent the center of the torsion coil spring 5 from deviating from the center of the driven shaft. Therefore, the vibration of the driven pulley can be reduced.

(A) is a schematic view of a state in which the movable pulley half is close to the fixed pulley half in the relief region by the V belt after wear in the low speed range state, and (B) is a V belt before wear in the low speed range state. Thus, the movable pulley half is close to the fixed pulley half, and (C) is a schematic view in the high speed range state. (A) is a schematic perspective view of a movable pulley half, a torsion coil spring, and a clutch part, (B) is an enlarged perspective view of a movable side boss part and a torsion coil spring, and (C) is a front view of the torsion coil spring. (A) is a schematic diagram showing a partial cross section of a driven pulley, (B) is a perspective view of the driven pulley, and (C) is an enlarged plan view of cam grooves and cam pin locations. (A) thru | or (C) is an effect | action figure of a torsion coil spring. (A) is a perspective view of a movable boss portion, (B) is an enlarged plan view of a cam groove of an embodiment in which a steeply inclined region portion and a gently inclined region portion are formed in a polygonal line, and (C) is a steeply inclined region. It is an enlarged plan view of the cam groove of the embodiment in which the portion and the gently inclined region portion are formed in an arc shape. (A) is a vertical side view of the driven pulley, and (B) is an enlarged view of the main part of (A). (A) is a front view of a support plate, (B) is a longitudinal side view of (A), and (C) is a schematic view of a state in which a torsion coil spring is supported by a support plate. (A) is a schematic diagram of the configuration of the prior art, (B) is a schematic diagram showing a state in which the winding changes due to wear of the V-belt, and (C) is an enlarged schematic diagram of the driven pulley of the prior art. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fixed pulley half, 12 ... Fixed boss | hub part, 13 ... Cam pin, 2 ... Movable pulley half,
22 ... movable boss part, 23 ... cam groove, 3 ... driven shaft, 4 ... clutch part,
5 ... Torsion coil spring.

Claims (5)

  A driven shaft, a fixed pulley half having a fixed boss portion formed with a cam pin on the outer periphery, a movable pulley half having a movable boss portion formed with a cam groove, and a clutch portion rotating together with the fixed pulley half; The cam groove is formed in an inclined direction gradually approaching the movable pulley face side along the rotational direction of the movable boss portion, and the fixed boss portion is inserted into the movable boss portion. The cam pin is inserted into the cam groove, and the torsion coil spring is twisted in the winding direction and has an elastic restoring force in advance. One end in the longitudinal direction is the half of the movable pulley and the other end is the clutch portion. A driven pulley of a V-belt type automatic transmission characterized by being locked and fixed.   2. The driven pulley of a V-belt type automatic transmission according to claim 1, wherein the cam groove has a steep inclination near the diameter direction of the movable boss portion with respect to the axial direction of the movable boss portion.   2. The cam groove according to claim 1, wherein the cam groove has a steep slope closer to the diameter direction of the movable boss portion with respect to the axial direction in a region close to the movable pulley face side, and the movable groove in a region away from the movable pulley face side. A driven pulley of a V-belt type automatic transmission characterized by a gentle inclination toward the axial direction of the boss portion.   4. A driven pulley of a V-belt type automatic transmission according to claim 3, wherein the steeply inclined region and the gently inclined region of the cam groove are substantially polygonal lines.   4. The driven pulley of a V-belt type automatic transmission according to claim 3, wherein the cam groove has a steeply inclined region and a gently inclined region formed continuously in a substantially arc shape.

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