JP2015007462A - V-belt type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize a V-belt type continuously variable transmission which changes the speed of a driven pulley with changes of a winding diameter of a V-belt due to changes of the groove width of a driving pulley and the driven pulley.SOLUTION: A driving pulley 20 and a driven pulley 30 around which a V-belt 40 are laid, are respectively formed by pairs of opposite pulleys 21 and 31. At least one side pulleys of the pairs of the opposite pulleys 21 and 31 are made to be moving pulleys capable of moving in an axial direction, and the moving pulleys are energized toward the opposite pulleys by coil springs 24 and 34. Between the pair of the opposite pulleys 21 in the driving pulley 20, a groove width adjusting member 50 contacting with tapered belt guiding surfaces 22 of the moving pulleys 21 is provided. The groove width adjusting member 50 is moved in a pulley diameter direction by a linear motion actuator 60, thereby downsizing the V-belt continuously variable transmission.

Description

  The present invention relates to a V-belt continuously variable transmission that rotates a driven pulley at a variable speed by a change in the winding diameter of a V-belt due to a change in groove width of a drive pulley and a driven pulley.

  As a V-belt type continuously variable transmission employed in a vehicle such as a motorcycle, one described in Patent Document 1 has been conventionally known. In this V-belt type continuously variable transmission, a V-belt is stretched between a driving pulley supported by a driving shaft and a driven pulley supported by a driven shaft, and the movable pulley in the driving pulley is slid in the axial direction by the operation of the actuator. The groove width of the driving pulley is changed, the movable pulley of the driven pulley is moved in the axial direction due to the fluctuation of the tension of the V belt due to the change of the winding diameter, and the groove width is changed. The driven pulley is rotationally rotated by changing the diameter.

  Here, the actuator includes an electric motor and a ball screw that operates using the electric motor as a drive source. The screw shaft that rotates the nut of the ball screw by the electric motor and engages the nut with the screw via the ball. By moving in the axial direction, the fork member is swung to move the movable pulley in the axial direction.

  In this case, if the screw shaft is rotated by the rotation of the nut, the screw shaft cannot be moved in the axial direction, so that it is necessary to prevent the screw shaft from rotating.

JP 2009-79759 A

  By the way, the conventional V-belt type continuously variable transmission described in Patent Document 1 requires a fork member supported so as to be able to swing, and the end of the fork member is pressed by a screw shaft of a ball screw. Fork members and actuators must be provided outside the V-belt, and the ball screw in the actuator must be built in so that the screw shaft is parallel to the drive shaft and driven shaft. The V-belt type continuously variable transmission is disadvantageously large.

  Also, in order to press the fork member at the shaft end of the screw shaft of the ball screw, it is necessary to provide another anti-rotation mechanism that prevents the ball screw screw shaft from rotating, which complicates the configuration and increases the number of parts. Inconvenience that takes time.

  An object of the present invention is to reduce the size of a V-belt continuously variable transmission that rotates a driven pulley by changing the winding diameter of the V-belt by changing the groove width of the driving pulley and the driven pulley.

  In order to solve the above problems, the present invention includes a drive pulley supported by a drive shaft, a driven pulley supported by a driven shaft, and a V-belt stretched between the drive pulley and the driven pulley. Each of the drive pulley and the driven pulley is composed of a pair of opposed pulleys, and at least one of the pair of opposed pulleys is a movable pulley movable in the axial direction, and the movable pulley is opposed to the other pulley by an elastic member. Between the pair of opposed pulleys in the drive pulley or between the pair of opposed pulleys in the driven pulley, a groove that contacts the tapered belt guide surface of the movable pulley at a portion where the belt is not wound A configuration in which a width adjusting member is provided and a linear actuator that moves the groove width adjusting member in the pulley radial direction is provided.

  In the V-belt type continuously variable transmission configured as described above, when the groove width adjusting member is incorporated between a pair of opposed pulleys forming the driving pulley, the groove width adjusting member is moved by the operation of the linear actuator. When moved in the pulley radial direction, the movable pulley moves relative to the opposite pulley, and the groove width of the drive pulley changes. Due to the change in the groove width, the winding diameter of the V-belt changes and the tension also changes, and due to the change in tension, the pair of opposed pulleys in the driven pulley move relatively to change the groove width. Due to the change, the driven pulley rotates at a variable speed.

  Even when the groove width adjusting member is incorporated between a pair of opposed pulleys forming the driven pulley, if the groove width adjusting member is moved in the pulley radial direction by the operation of the linear actuator, the driven pulley and the drive are driven. The respective groove widths of the pulleys change, and the driven pulley rotates at a variable speed by changing the winding diameter of the V-belt.

  In the V-belt type continuously variable transmission according to the present invention, as described above, the groove width adjusting member is moved in the pulley radial direction by the linear actuator, so that the movable pulley is axially relative to the opposed pulley. Since the groove width changes due to movement, a member such as the fork member described in Patent Document 1 is not required, and the linear actuator is also capable of moving the groove width adjusting member and the groove width adjusting member in the pulley radial direction. Can be incorporated into a space surrounded by the V-belt, and the V-belt continuously variable transmission can be reduced in size.

  Here, as the groove width adjusting member, it is possible to employ a member comprising a roller that is in contact with the belt guide surface of the movable pulley and a roller support that rotatably supports the roller.

  In adopting the groove width adjusting member as described above, since the roller rotates by contact with the movable pulley, the rotational resistance at the contact portion is small, and the pulley on the side where the groove width is adjusted by the groove width adjusting member is smooth. The fuel consumption in the engine can be suppressed.

  If a contact surface having an arcuate cross section is provided on the outer peripheral portion of the surface of the roller facing the movable pulley, the roller can be smoothly contacted and moved radially inward along the belt guide surface of the movable pulley. The pulley can be smoothly moved relatively in the direction away from the facing roller.

  Further, as the linear actuator, it is possible to employ a ball screw that has a nut that is rotationally driven by an electric motor and moves the screw shaft in the axial direction by the rotation of the nut.

  In the use of the ball screw as described above, the screw shaft is disposed inside the V belt so as to be orthogonal to the drive shaft and the driven shaft, and the groove width adjusting member is supported at the tip of the screw shaft, and the screw By moving the groove width adjusting member in the pulley radial direction by moving the shaft in the axial direction, a small V-belt type continuously variable transmission can be obtained.

  Further, since the screw shaft is prevented from rotating by the groove width adjusting member that contacts the movable pulley, it is not necessary to provide a separate locking means, and the number of parts can be reduced and assembly can be facilitated.

  Here, when the screw shaft of the ball screw is urged by the elastic member toward the direction in which the groove width adjusting member is pushed between the pair of opposed pulleys, the groove width adjusting member presses the movable pulley against the opposing pulley. When making the relative movement in the separating direction, the reaction force at the time of pressing applied to the screw shaft from the movable pulley can be absorbed by the elastic member, reducing the load on the electric motor that rotates the nut, and as an electric motor A small electric motor with a small capacity can be employed.

  In the present invention, as described above, the groove width adjusting member is moved in the radial direction by the linear actuator, and the groove width is changed by relatively moving the pair of opposed pulleys in the axial direction with a simple configuration with a small number of parts. In addition, since each of the groove width adjusting member and the linear motion actuator that moves the groove width adjusting member in the pulley radial direction can be incorporated into the space surrounded by the V belt, an extremely small V belt type A step transmission can be provided.

A longitudinal sectional view showing an embodiment of a V-belt type continuously variable transmission according to the present invention Sectional view along the line II-II in FIG. Sectional drawing which expands and shows the installation part of the groove width adjustment member and linear motion actuator which are shown in FIG. A longitudinal sectional view showing another embodiment of a V-belt type continuously variable transmission according to the present invention

  Embodiments of the present invention will be described below with reference to FIGS. 1 to 3 of the drawings. As shown in the figure, the V-belt type continuously variable transmission according to the present invention has a transmission case 10.

  The transmission case 10 includes a case main body 11 and a cover 12 that closes a peripheral wall opening of the case main body 11, and shaft insertion holes 13 and 14 are provided in one end and the other end of the case main body 11, respectively. It has been.

  A primary shaft 15 as a drive shaft is inserted into a shaft insertion hole 13 provided in one end portion of the case body 11 so that the end portion faces the transmission case 10. The primary shaft 15 is rotatably supported by a bearing 16 incorporated in the shaft insertion hole 13.

  On the other hand, a secondary shaft 17 as a driven shaft is inserted into a shaft insertion hole 14 provided in the other end portion of the case body 11, and a shaft end portion faces the transmission case 10. The secondary shaft 17 is rotatably supported by a bearing 18 incorporated in the shaft insertion hole 14.

  A V-belt type continuously variable transmission mechanism A is accommodated in the transmission case 10. The V-belt type continuously variable transmission mechanism A includes a drive pulley 20 supported by the primary shaft 15, a driven pulley 30 supported by the secondary shaft 17, and a V-belt 40 spanned between these pulleys 20, 30. have.

  Further, the V-belt type continuously variable transmission mechanism A includes a groove width adjusting member 50 that adjusts the groove width of the drive pulley 20 and a linear actuator 60 that moves the groove width adjusting member 50 in the pulley radial direction. .

  The driving pulley 20 includes a pair of dish-shaped movable pulleys 21 and 21. The pair of movable pulleys 21 and 21 are fitted to the primary shaft 15 so that the tapered belt guide surfaces 22 face each other, are prevented from rotating by a spline 23 provided on the outer diameter surface of the primary shaft 15, and It is slidably supported in the axial direction.

  Further, each of the pair of movable pulleys 21 is urged toward a direction approaching each other by a pair of coil springs 24 as elastic members provided on the outside of the primary shaft 15. One of the coil springs 24 provided on the shaft is supported by a spring seat 25 provided at the end of the shaft.

  The driven pulley 30 is composed of a pair of dish-shaped movable pulleys 31, 31, similar to the drive pulley 20. The pair of movable pulleys 31, 31 are fitted to the secondary shaft 17 with the tapered belt guide surface 32 facing each other, and are prevented from rotating by a spline 33 provided on the outer diameter surface of the secondary shaft 17, and It is slidably supported in the axial direction.

  In addition, each of the pair of movable pulleys 31 is urged toward a direction in which the pair of movable pulleys 31 approach each other by a pair of coil springs 34 as elastic members provided outside the secondary shaft 17. One of the coil springs 34 provided at the end is supported by a spring seat 35 provided at the end of the shaft.

  The groove width adjusting member 50 is incorporated between opposing portions of the pair of movable pulleys 21 that form the drive pulley 20. At this time, the groove width adjusting member 50 is incorporated in a portion where the belt 40 of the pair of movable pulleys 21 is not wound.

  As shown in FIG. 3, the groove width adjusting member 50 includes a pair of rollers 51 that are in contact with the belt guide surfaces 22 of the pair of opposed movable pulleys 21 and a roller support that rotatably supports the pair of rollers 51. It consists of a body 52.

  The roller support 52 has a pair of roller shafts 53 on both sides, and a bearing 54 is fitted to each of the pair of roller shafts 53, and each of the pair of rollers 51 is rotatably supported by each bearing 54. ing.

  The roller 51 has a contact surface 51 a having a circular arc cross section on the outer peripheral portion of the surface facing the movable pulley 21, and the contact surface 51 a is in contact with the belt guide surface 22 of the movable pulley 21.

  The actuator 60 that moves the groove width adjusting member 50 in the pulley radial direction is provided on the inner surface of the case main body 11 and supported by the support base 19 whose tip is located in the space inside the V-belt 40.

  The linear actuator 60 includes an electric motor 61 and a ball screw 62 that uses the electric motor 61 as a drive source. The ball screw 62 includes a nut 63 that is rotated by using the electric motor 61 as a drive source, and a screw shaft 64 that is screw-engaged via a ball that is incorporated along a thread groove of the nut 63. Between the nut 63 and the electric motor 61, a gear reduction mechanism 65 that reduces the rotation of the rotor shaft 61a of the electric motor 61 and transmits it to the nut 63 is provided.

  The gear reduction mechanism 65 includes an input gear 65a attached to the rotor shaft 61a of the electric motor 61 and an output gear 65b having a larger diameter than the input gear 65a attached to the nut 63 and meshing with the input gear 65a.

  The ball screw 62 has a screw shaft 64 inserted into a shaft insertion hole 66 formed at the tip of the support base 19, and the screw shaft 64 is positioned inside the V-belt 40. The roller support 52 of the groove width adjusting member 50 is provided at the tip of the screw shaft 64.

  The nut 63 is incorporated in a fitting hole 67 formed coaxially with the shaft insertion hole 66, and a bearing 68 incorporated in the fitting hole 67 rotatably supports the nut 63.

  A cylindrical body 69 covering the shaft end of the screw shaft 64 is attached to the support base 19, and an elastic member 70 incorporated in the closed end of the cylindrical body 69 urges the screw shaft 64 toward the drive pulley 20. ing.

  The V-belt type continuously variable transmission shown in the embodiment has the above structure, and the electric motor 61 in the linear motion actuator 60 is controlled by a control unit (not shown). Now, when the primary shaft 15 rotates and the driving pulley 20 rotates with the primary shaft 15, the rotation is transmitted to the driven pulley 30 via the V belt 40, and the driven pulley 30 rotates in the same direction as the driving pulley 20. Then, the rotation of the driven pulley 30 is transmitted to the secondary shaft 17.

  When the electric motor 61 is rotated in the state of transmitting the rotation from the primary shaft 15 to the secondary shaft 17, the rotation is transmitted to the nut 63 via the gear reduction mechanism 65, and the screw shaft 64 is axially moved by the rotation of the nut 63. Move to.

  Since the groove width adjusting member 50 is provided at the tip of the screw shaft 64, the groove width adjusting member 50 moves in the radial direction of the drive pulley 20 by the movement of the screw shaft 64 in the axial direction. Here, when the screw shaft 64 moves backward in the direction indicated by the arrow in FIG. 3 due to the forward rotation of the electric motor 61, the groove width adjusting member 50 moves radially outward, and the elastic force of the coil spring 24. As a result, the pair of movable pulleys 21 forming the drive pulley 20 moves in a direction approaching each other.

  The relative movement of the pair of movable pulleys 21 in the approaching direction increases the winding diameter of the V-belt 40 and increases the tension of the V-belt 40, so that the pair of movable pulleys 31 forming the driven pulley 30 are connected to the coil spring 34. Relative movement in the direction away from each other against elasticity, the groove width in the driven pulley 30 is increased, and the winding diameter of the V-belt 40 is decreased.

  As a result, the rotation of the drive pulley 20 is increased and transmitted to the driven pulley 30, and the secondary shaft 17 rotates at an increased speed.

  On the other hand, when the electric motor 61 is rotated in the reverse direction, the screw shaft 64 moves forward in the direction opposite to the direction indicated by the arrow in FIG. 3, and the groove width adjusting member 50 moves inward in the radial direction of the drive pulley 20. Move towards. At this time, the pair of rollers 51 of the groove width adjusting member 50 presses the tapered belt guide surfaces 22 of the pair of movable pulleys 21 forming the drive pulley 20, so that the pair of movable pulleys 21 is elastic to the coil spring 24. In the opposite direction, they move relative to each other.

  Due to the relative movement of the pair of movable pulleys 21 in the separating direction, the groove width of the drive pulley 20 is increased, the winding diameter of the V belt 40 is decreased, and the tension of the V belt 40 is decreased. At this time, the pair of movable pulleys 31 forming the driven pulley 30 move relative to each other in the direction approaching each other by the pressing of the coil spring 34, the groove width in the driven pulley 30 is reduced, and the winding diameter of the V belt 40 is increased.

  As a result, the rotation of the drive pulley 20 is decelerated and transmitted to the driven pulley 30, and the secondary shaft 17 rotates at a reduced speed.

  Here, when the groove width adjusting member 50 moves inward in the radial direction of the drive pulley 20 and presses the pair of movable pulleys 21, the pair of rollers 51 of the groove width adjusting member 50 are contact surfaces 51a having an arcuate cross section. In order to press the tapered belt guide surfaces 22 of the pair of movable pulleys 21, the groove width adjusting member 50 moves smoothly inward in the radial direction, and the pair of movable pulleys 21 moves smoothly in the direction away from each other.

  Further, when the groove width adjusting member 50 presses and moves the pair of movable pulleys 21 in a direction away from each other, a reaction force due to the pressing is applied to the screw shaft 64.

  At this time, the elastic force is applied to the screw shaft 64 by the elastic member 70, and the elastic force assists the forward movement of the screw shaft 64 and acts to cancel the reaction force applied to the screw shaft 64. The shaft 64 moves forward smoothly. Further, the load on the electric motor 61 is greatly reduced, and a small electric motor 61 can be employed.

  Since the pair of rollers 51 of the groove width adjusting member 50 that adjusts the groove width of the driving pulley 20 is rotatable support, when the pair of movable pulleys 21 forming the driving pulley 20 rotate, the pair of rollers 51 rotate in contact with each other. To do. For this reason, the pair of movable pulleys 21 can smoothly rotate without being hindered by the groove width adjusting member 50, and fuel consumption in the engine can be suppressed.

  In the V-belt type continuously variable transmission according to the embodiment, the groove width adjusting member 50 is incorporated between the pair of movable pulleys 21 forming the drive pulley 20, and the groove width adjusting member 50 is attached to the screw shaft 64 of the ball screw 62. Since the groove width of the drive pulley 20 is changed by moving in the pulley radial direction by moving in the axial direction, the number of parts is small and the ball screw 62 can be incorporated inside the V belt 40. An extremely small V-belt continuously variable transmission can be provided.

  In the embodiment, a groove width adjusting member 50 is provided between the pair of movable pulleys 21 forming the driving pulley 20, and the groove width adjusting member 50 is moved in the radial direction of the driving pulley 20 by the linear motion actuator 60. Although the groove width of the drive pulley 20 is changed, a groove width adjusting member 50 is incorporated between a pair of movable pulleys 31 forming the driven pulley 30, and the groove width adjusting member 50 is driven by the linear actuator 60. The groove width of the driven pulley 30 may be changed by moving in the radial direction of 30.

  In FIG. 1, each of the driving pulley 20 and the driven pulley 30 is formed by a pair of opposed movable pulleys 21 and 31 that are movable in the axial direction, and each of the pair of movable pulleys 21 and 31 is formed by coil springs 24 and 34. Although biased toward the direction of approaching each other, at least one of the pair of opposed pulleys is a movable pulley that can move in the axial direction, and the movable pulley is biased toward the facing pulley by a coil spring. May be.

  That is, as shown in FIG. 4, the drive pulley 20 is formed by a pair of opposed pulleys 26, 27, one pulley 26 is a movable pulley that can move in the axial direction, and the other pulley 27 is between the spring seat 25. The movement toward the spring seat 25 may be restricted by the collar 28 incorporated into the spring 28, and the movable pulley 26 may be biased toward the facing pulley 27 by the coil spring 24. Similarly to the drive pulley 20, the driven pulley 30 is also formed by a pair of opposed pulleys 36, 37, one pulley 36 being a movable pulley movable in the axial direction, and the other pulley 37 being between the spring seat 35. The movement toward the spring seat 35 may be restricted by the collar 38 incorporated in the, and the movable pulley 36 may be biased toward the facing pulley 37 by the coil spring 34.

  In this case, the roller 51 is brought into contact only with the belt guide surface 22 of the movable pulley 26 in the drive pulley 20, and the roller 51 is rotatably supported by a roller support 52 provided at the tip of the screw shaft 64. The movable pulley 26 is moved relative to the opposed pulley 27 by moving the pulley 51 in the pulley radial direction.

15 Primary shaft (drive shaft)
17 Secondary shaft (driven shaft)
20 Driving pulley 21 Movable pulley 22 Belt guide surface 24 Coil spring (elastic member)
26 movable pulley 30 driven pulley 31 movable pulley 32 belt guide surface 34 coil spring (elastic member)
36 movable pulley 40 V belt 50 groove width adjusting member 51 roller 51a contact surface 52 roller support 60 linear motion actuator 61 electric motor 62 ball screw 63 nut 64 screw shaft 70 elastic member

Claims (5)

  A driving pulley supported by the driving shaft; a driven pulley supported by the driven shaft; and a V-belt stretched between the driving pulley and the driven pulley, each of the driving pulley and the driven pulley facing each other The pulley is a pulley, and at least one of the pair of opposed pulleys is an axially movable movable pulley, and the movable pulley is urged toward the other opposed pulley by an elastic member, and the opposed pair of the drive pulleys A groove width adjusting member that comes into contact with the tapered belt guide surface of the movable pulley is provided between the pulleys or between the pair of opposed pulleys in the driven pulley at a portion where the belt is not wound, and the groove width adjusting member is connected to the pulley. A V-belt continuously variable transmission provided with a linear actuator that moves in the radial direction.   The V-belt type continuously variable transmission according to claim 1, wherein the groove width adjusting member includes a roller that contacts a belt guide surface of the movable pulley and a roller support that rotatably supports the roller.   The V-belt type continuously variable transmission according to claim 2, wherein the roller has a contact surface having an arcuate cross section on an outer peripheral portion of a surface facing the movable pulley.   The linear motion actuator comprises a ball screw having a nut rotated by an electric motor and moving the screw shaft in the axial direction by the rotation of the nut, and the screw shaft in the ball screw is arranged inside the V-belt. In FIG. 4, the groove width adjusting member is arranged so as to be orthogonal to the drive shaft and the driven shaft, and the groove width adjusting member is supported by the tip end portion of the screw shaft. The V-belt type continuously variable transmission according to any one of claims 1 to 3, wherein the V-belt type continuously variable transmission is moved.   The V-belt type continuously variable transmission according to claim 4, wherein the screw shaft of the ball screw is urged by an elastic member in a direction in which the groove width adjusting member is pushed between a pair of opposed pulleys.

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