JP4463859B2 - V-belt type automatic transmission driven pulley - Google Patents

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 is provided with a mechanism (torque cam mechanism) for changing 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. A V-belt type automatic transmission (CVT) exists, 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. 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, belt rubber. Cause problems such as aging due to compression and tension.

  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 contacting 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 locked at one end in the longitudinal direction. An end portion is locked to the locked portion of the movable pulley half, a locking end portion of the other end is locked to the clutch portion, and the locking end portion of the torsion coil spring and the locked portion are: Within appropriate range And the V-belt is worn in the width direction and the width direction dimension is shortened without causing the torsion coil spring to generate a negative restoring force that spreads in the opposite direction to the twist. In the case where the cam pin moves, and the escape region where the movable pulley half can move closer to the fixed pulley half is the cam groove, the fixed pulley half, and the movable pulley half. The above-described problems have been solved by using a driven pulley of a V-belt type automatic transmission that is provided in advance with the body.

  According to a second aspect of the present invention, in the above-described configuration, the torsion coil spring is a driven pulley of a V-belt type automatic transmission in which a twist is applied in a winding direction and has an elastic restoring force in advance. Solved. According to a third aspect of the present invention, in the above-described configuration, the locked portion is a driven pulley of a V-belt type automatic transmission that is a long hole, thereby solving the above problem. According to a fourth aspect of the present invention, there is provided a V-belt type in which, in the above-described configuration, the locked portion is formed with protrusions at an appropriate interval, and the locking end portion of the torsion coil spring is disposed between both protrusions. By using a driven pulley of the automatic transmission, the above-described problem has been solved.

  According to the first aspect of the present invention, when the driven pulley moves from the high speed range state to the low speed range state (LOW) in the driven pulley after the V belt wears, the locking end portion of the torsion coil spring is restored by the rotation of the movable pulley half. Further, it is possible to prevent the movable pulley half from following the rotation after the value becomes zero, and to prevent the torsion coil spring from spreading in the opposite direction to twisting, that is, to generate a negative elastic force. This can prevent the reacceleration performance from being lowered. According to the second aspect of the present invention, the torsion coil spring is twisted to have an elastic restoring force in advance, and can sufficiently cope with the V belt 7 after being worn. According to the third and fourth aspects of the invention, since the locked portion is a long hole, the structure can be simplified.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 shows a driven pulley mechanism according to the present invention. As shown in FIG. 7A, the driven pulley mechanism mainly includes a fixed pulley half 1, a movable pulley half 2, a clutch portion 4, and a torsion coil spring 5. 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.

  The fixed boss portion 12 of the fixed pulley half 1 is rotatably supported by 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 region S is also present 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 (see FIG. 2). .

  A clutch portion 4 is mounted on the other end side of the fixed boss portion 12 of the driven pulley. 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 provided with a support plate 43 so as to cover the clutch weights 42, 42,. 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. 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 torsion coil spring 5 has locking end portions 52 and 52 formed at both ends in the longitudinal direction of the coiled portion 51.

  The locking end portion 52 is formed as a shaft piece that is appropriately bent around the end portion of the wire constituting the coil-shaped portion 51, and the locking end portion 52 that is the shaft piece is the coil piece. The shape part 51 is formed in the same direction as the expansion / contraction direction (longitudinal direction). The locking end portions 52 are 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. 7, 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 locking end 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 other end side locking end 52 is the movable boss portion 22 of the movable pulley half 2 or movable. It is locked and fixed to a locked portion 24 formed on the pulley face 21. The locking end portion 52 and the locked portion 24 are movable relative to each other within an appropriate range. Specifically, it is formed as a long hole 24a. Further, as another embodiment of the locked portion 24, it is composed of the two protruding pieces 24b and 24b of FIG. 2D, and the locking end 52 is located between the protruding pieces 24b and 24b. Are movable between each other.

  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 present invention will be described. The operation of the torsion coil spring 5 and the cam groove 23 (including the cam pin 13) will be described with reference to FIGS. As shown in FIG. 1B, when the twist of the width T in the winding direction is applied and the state having the elastic restoring force in advance is set as the initial twist setting T, FIG. 3 and FIG. No torsion coil spring 5 is used. 5 and 6 show a case where a torsion coil spring 5 to which an initial torsion setting T is added is used. 4 and 6, a is a stop (fixed) position before wear of the V belt 7 in the low speed range (LOW), and b is a stop (fixed) position after wear of the V belt 7 in the low speed range (LOW). , C is the stop (fixed) position in the high speed range state (TOP), d is the fixed position of the torsion coil spring 5 on the clutch part 4 side [a 'is the restoring force F1, F2 described below is both 0 (zero) (Stopped (fixed) position).

  When the driven pulley transitions from the high speed range state (TOP) to the low speed range state (LOW), the movable pulley half 2 is biased by the restoring force F1 generated when the low speed range state shifts to the high speed range state. At this time, if the V-belt 7 is worn, the space between the driven pulleys is narrowed by the axial pressing force (compression direction) of the torsion coil spring 5. That is, the cam groove 23 of the movable pulley half 2 on the driven side is relatively rotated further toward the fixed pulley half 1 side and rotated to the clearance width of the cam groove 23. From the above, the process of urging the torsion coil spring 5 against the thrust of the movable pulley half 2 is as follows. The transition from the high speed region state (TOP) to the low speed region state (LOW) is achieved by the locked portion 24 such as the long hole 24a provided in the movable pulley half body 2 even if the movable pulley half body 2 rotates. The locking end 52 of the torsion coil spring 5 does not move. Therefore, when the movable pulley half 2 is rotated from the position a where F1 = 0 to the position b, the restoring force F3 in the reverse direction as in the prior art does not occur. In the transition from the low speed region state to the high speed region state, a positive elastic restoring force F1 is stored. Next, in the transition from the high speed region state to the low speed region state, the elastic restoring force F1 in the rotational direction of the movable pulley half 2 is obtained, and the axial biasing force of the movable pulley does not decrease (see FIGS. 3 and 4).

  Next, in the case where the initial torsion setting T is added to the torsion coil spring 5, the elastic restoring force F2 acts in the same direction as the rotation direction of the driven shaft 3, and is assembled to the movable pulley half 2 and the clutch portion 4. The movable pulley half 2 is rotated relative to the fixed pulley half 1 and the clutch portion 4, and the restoring force F2 of the torsion coil spring 5 is stored. Similarly to the prior art, the elastic pulley F1 of the torsion coil spring 5 is stored by rotating the movable pulley half 2 during the transition from the low speed region state to the high speed region state (see FIG. 6).

When the driven pulley transitions from the high speed region state to the low speed region state, it receives the bias of the restoring force F1 + F2 generated when the movable pulley transitions from the low speed region state to the high speed region state. At this time, if the V-belt 7 is worn, the space between the driven pulleys is narrowed by the axial pressing force (compression direction) of the torsion coil spring 5. That is, when the cam groove 23 of the movable pulley half 2 on the driven side is rotated relative to the fixed pulley half 1 side and rotates in the relief region S of the cam groove 23, the following occurs.
First, in the transition from the high speed region state to the low speed region state, even if the movable pulley rotates, the fixed end of the spring does not move due to the long hole 24a provided in the movable pulley. Accordingly, when the movable pulley half is further rotated two times from the position a ′ where F1 = 0 and F2 = 0, the restoring force F3 in the reverse direction as in the prior art does not occur. Next, in the transition from the low speed region state to the high speed region state, a positive restoring force F1 + F2 is stored. Furthermore, in the transition from the high speed region state to the low speed region state, the restoring force in the rotational direction of the movable pulley half 2 is F1 + F2, and the axial biasing force of the movable pulley half 2 is the same as in the case of only the elastic restoring force F1. Does not decrease (see FIGS. 5 and 6).

(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, (C) is a front view of the torsion coil spring, and (D) is a front view of the torsion coil spring. It is an enlarged view of other embodiment which provided the projection piece in the to-be-latched part of the torsion coil spring. (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 perspective view of the state where the movable pulley half and the torsion coil spring are separated, and (B) and (C) are enlarged views of the state where the locking end and the locked portion are locked. (A) thru | or (C) is an effect | action figure of this invention. (A) is a perspective view of the state where the movable pulley half and the torsion coil spring are separated, and (B) and (C) are enlarged views of the state where the locking end and the locked portion are locked. (A) thru | or (C) is an effect | action figure of this invention. (A) is a longitudinal side view of a driven pulley, and (B) is an enlarged view of a main part of FIG. (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 body, 12 ... Fixed boss | hub part, 13 ... Cam pin, 2 ... Movable pulley half body,
22 ... movable boss part, 23 ... cam groove, 24 ... locked part, 3 ... driven shaft, 4 ... clutch part,
5 ... Torsion coil spring.

Claims (4)

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. In addition, the cam pin is inserted into the cam groove, and the torsion coil spring has a locking end at one end in the longitudinal direction at a locked portion of the movable pulley half, and a locking end at the other end in the clutch portion. locked, and the locking end portion and the locked portion of the torsion coil spring is adapted to freely move relative to each other within an appropriate range, spread to the twisting direction opposite to the torsion coil spring Without causing a negative restoring force, and the V-belt is worn in the width direction, when the widthwise dimension shortened, a region where the cam pin is moved and the movable pulley half said fixed pulley A V-belt type automatic transmission characterized in that a relief area capable of moving close to the half side is provided in advance between the cam groove and the fixed pulley half and the movable pulley half, respectively . Driven pulley.   2. A driven pulley of a V-belt type automatic transmission according to claim 1, wherein the torsion coil spring is twisted in a winding direction and has an elastic restoring force in advance.   3. The driven pulley of a V-belt type automatic transmission according to claim 1, wherein the locked portion is a long hole.   3. The V-belt type according to claim 1, wherein the locked portion is formed with a protrusion at an appropriate interval, and the locking end portion of the torsion coil spring is disposed between both the protrusions. The driven pulley of the automatic transmission.

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