Reverse input prevention clutch and actuator for continuously variable transmission

Abstract

To provide a reverse input prevention clutch in which the locking and unlocking operations of an output shaft are gentle and noise is less likely to be generated.SOLUTION: A reverse input prevention clutch has an eccentric shaft part 3 with a cylindrical outer peripheral surface 16 formed on its outer periphery, with its center C1 at a position eccentric to a rotation center C0 of an input shaft 1, and urges a pair of engaging elements 9a, 9b each having an outer peripheral side engaging surface 23 extending along a cylindrical inner peripheral surface 11 of a stationary member, so as to press them against the cylindrical inner peripheral surface 11 of the stationary member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reverse input prevention clutch and an actuator for a continuously variable transmission equipped with the same. [Background technology]

[0002] A belt-type continuously variable transmission has a drive pulley, a driven pulley, and a transmission belt wound between the drive pulley and the driven pulley. The drive pulley is composed of a fixed sheave and a movable sheave that face each other in the axial direction. A V-groove, around which the transmission belt is wound, is formed between the fixed sheave and the movable sheave that face each other in the axial direction. That is, one of the slopes of the V-groove is formed in the fixed sheave, and the other slope of the V-groove is formed in the movable sheave, and the width of the V-groove can be changed by moving the movable sheave in the axial direction. An actuator that moves the movable sheave in the axial direction is attached to the movable sheave. The driven pulley is configured in the same way as the drive pulley.

[0003] In this belt-type continuously variable transmission, when the movable sheave is moved axially by an actuator, the width of the V-groove between the fixed sheave and the movable sheave changes, thereby continuously changing the winding diameter of the power transmission belt around the drive pulley and the driven pulley, thereby continuously adjusting the speed ratio.

[0004] The actuator that moves the movable sheave in the axial direction has an electric motor, a rotation transmission path that transmits rotation output from the electric motor, and a motion conversion mechanism that converts the rotation transmitted from the electric motor via the rotation transmission path into axial movement. This actuator transmits the rotation generated by the electric motor to the motion conversion mechanism via the rotation transmission path, and the motion conversion mechanism converts the rotation into axial movement, thereby moving the movable sheave in the axial direction.

[0005] In the belt-type continuously variable transmission described above, the axial position of the movable sheave needs to be maintained against the axial component of the force received from the transmission belt. That is, the movable sheave and the fixed sheave are subjected to a radially inward force from the transmission belt, which is wound around the V-groove formed by the movable sheave and the fixed sheave. Here, an axial component of force acting in a direction away from the fixed sheave acts on the slope of the V-groove of the movable sheave. Therefore, unless the axial position of the movable sheave is maintained by some method, the movable sheave will move axially, changing the width of the V-groove between the movable sheave and the fixed sheave.

[0006] Therefore, one possible method for maintaining the axial position of the movable sheave is to use the torque generated by the electric motor. That is, torque is generated by the electric motor, and this torque is transmitted to the movable sheave as an axial force via the rotation transmission path and the motion conversion mechanism. This axial force cancels out the axial component of the force received from the transmission belt, thereby preventing the movable sheave from moving axially and maintaining the width of the V-groove between the movable sheave and the fixed sheave.

[0007] However, if the axial position of the movable sheave is maintained using the torque of the electric motor, it is necessary to supply power to the electric motor not only when the axial position of the movable sheave is being moved, but also at all times while the axial position of the movable sheave is being maintained without movement, and it is also necessary to make the electric motor larger in order to ensure the torque necessary to prevent the axial movement of the movable sheave.

[0008] Therefore, as a method for maintaining the axial position of the movable sheave without using an electric motor, the applicant of the present application has already proposed a method of incorporating a reverse input prevention clutch into an actuator that moves the movable sheave axially, as in Patent Documents 1 and 2. The reverse input prevention clutch transmits rotation of the input shaft to the output shaft when rotation is input to the input shaft, and on the other hand, locks the output shaft (prevents rotation of the output shaft) when rotation is input to the output shaft, thereby preventing transmission of rotation from the output shaft to the input shaft. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-263285 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-263268 Summary of the Invention [Problem to be solved by the invention]

[0010] However, the reverse input prevention clutches of Patent Documents 1 and 2 have a problem in that the locking and unlocking operations of the output shaft are sudden.

[0011] Specifically, the reverse input prevention clutch of Patent Document 1 includes an input shaft, an output shaft whose center of rotation is the same as that of the input shaft, and multiple pairs of rollers mounted between the outer periphery of the output shaft and the inner periphery of a housing (stationary member). Multiple cam surfaces are formed at circumferential intervals on the outer periphery of the output shaft, and wedge-shaped spaces that gradually narrow on both circumferential sides are formed between each cam surface and the cylindrical inner periphery of the housing. A pair of rollers is disposed in each wedge-shaped space. Each pair of rollers is held by a cage connected to the input shaft so that they rotate integrally with the input shaft. An engagement protrusion on the output shaft is inserted into an engagement hole on the input shaft with a circumferential gap between them. When rotation is input to the input shaft, only the input shaft rotates within a range where the engagement protrusion does not contact the circumferential end of the engagement hole. After the engagement protrusion contacts the circumferential end of the engagement hole, the input shaft and output shaft rotate integrally.

[0012] When rotation is input to the output shaft, the rear roller of each pair of rollers in the direction of rotation engages between the cam surface on the outer periphery of the output shaft and the cylindrical inner periphery of the housing, locking the output shaft. When rotation is then input to the input shaft, the cage, which rotates integrally with the input shaft, presses the rear roller of each pair of rollers in the direction of rotation, causing the rear roller to disengage and unlock the output shaft. Then, the input shaft and output shaft rotate integrally due to engagement between the engaging protrusion and engaging hole.

[0013] Here, the action of locking the output shaft (the action of preventing the rotation of the output shaft) is a sudden action caused by the rollers getting caught, and the action of unlocking the output shaft is also a sudden action caused by the rollers getting unhooked.

[0014] Therefore, if this reverse input prevention clutch is incorporated into the above-mentioned actuator that moves the movable sheave axially, there is a problem that the movable sheave does not move smoothly when it is moved axially away from the fixed sheave.

[0015] In the actuator incorporating the reverse input prevention clutch of Patent Document 1, the axial component force acting on the movable sheave from the transmission belt is transmitted to the output shaft via the motion conversion mechanism, thereby constantly applying torque to the output shaft. Meanwhile, when the movable sheave is moved axially away from the fixed sheave, torque generated by the electric motor acts on the input shaft. In this case, the rotational direction of the torque acting on the input shaft from the electric motor is the same as the rotational direction of the torque acting on the output shaft from the transmission belt. If the torque acting from the transmission belt causes the output shaft to rotate faster than the input shaft, the positional relationship between the cage, which rotates integrally with the input shaft, and the output shaft changes, causing the rear roller in the rotational direction to become engaged between the cam surface on the outer periphery of the output shaft and the cylindrical inner periphery of the housing, locking the output shaft. The input shaft continues to rotate even after the output shaft is locked, and the cage, which rotates integrally with the input shaft, presses the rear roller in the rotational direction, releasing the roller from the engagement and unlocking the output shaft. The engagement of the engaging projection and the engaging hole transmits torque from the input shaft to the output shaft. However, the unlocked output shaft immediately begins to rotate due to the torque acting from the transmission belt, and once again, due to the difference in rotational speed between the output shaft and the input shaft, the roller on the rear side in the rotational direction engages, locking the output shaft.

[0016] The above series of operations are repeated, causing the movable sheave to move in the axial direction. Here, in the reverse input prevention clutch of Patent Document 1, the locking and unlocking operations of the output shaft are sudden operations caused by the rollers engaging and then disengaging. Therefore, the axial movement of the movable sheave becomes an intermittent operation that repeats sudden movements and stops, which causes the problem that the movable sheave does not move smoothly.

[0017] Furthermore, in the reverse input prevention clutch of Patent Document 1, the rollers are engaged with high surface pressure, which can cause abnormal noise when the rollers disengage. Therefore, when the output shaft is repeatedly locked and unlocked in the above series of operations, abnormal noise can be repeatedly generated, which can cause discomfort to the user.

[0018] Furthermore, Patent Document 2 proposes a reverse input prevention clutch similar to that of Patent Document 1, in which multiple balls are incorporated at circumferential intervals around the outer periphery of the output shaft, and the multiple balls are engaged axially between the housing and the output shaft to lock the output shaft. However, when this reverse input prevention clutch is incorporated into an actuator that moves the movable sheave of a continuously variable transmission in the axial direction, similar to Patent Document 1, there are problems in that the movable sheave does not operate smoothly and abnormal noises are generated.

[0019] The problem to be solved by this invention is to provide a reverse input prevention clutch in which the locking and unlocking operations of the output shaft are gradual and noise is unlikely to occur. [Means for solving the problem]

[0020] In order to solve the above problems, the present invention provides a reverse input prevention clutch having the following configuration. [Configuration 1] an input shaft to which rotation is input; an output shaft having an eccentric shaft portion having a cylindrical outer peripheral surface formed on an outer periphery thereof, the eccentric shaft portion being centered at a position eccentric to the rotation center of the input shaft, and supported so as to be rotatable about the same position as the rotation center of the input shaft; a stationary member having a cylindrical inner peripheral surface formed in a cylindrical shape centered on the rotation center of the input shaft; an annular eccentric space formed between the cylindrical inner peripheral surface and the cylindrical outer peripheral surface, the radial width of which gradually increases from a narrow portion located in the eccentric direction of the eccentric shaft portion to a wide portion located in the opposite direction to the eccentric direction of the eccentric shaft portion; an engaging element pressing portion disposed in the narrow portion of the eccentric space and coupled to the input shaft so as to move integrally with the input shaft in the circumferential direction; an input-side transmission portion provided on the input shaft so as to rotate integrally with the input shaft; an output-side transmission portion that is provided on the output shaft so as to rotate integrally with the output shaft and that engages with the input-side transmission portion with circumferential play; a pair of engaging pieces that are accommodated in a pair of arc-shaped spaces formed between the narrow portion and the wide portion of the eccentric space and that face end surfaces on both sides in the circumferential direction of the engaging piece pressing portion, the pair of engaging elements each have a partially cylindrical outer peripheral engaging surface extending along the cylindrical inner peripheral surface of the stationary member, a reverse input prevention clutch provided with an elastic member that biases the pair of engaging elements so as to press the outer peripheral engaging surfaces of the pair of engaging elements against the inner peripheral surface of the cylinder;

[0021] In this configuration, when rotation is input to the output shaft, the eccentric shaft attempts to rotate integrally with the output shaft. However, the cylindrical outer circumferential surface of the eccentric shaft immediately presses the engagement element on the front side in the direction of rotation against the narrow portion of the eccentric space, forcing the partially cylindrical outer circumferential engagement surface of the engagement element against the cylindrical inner circumferential surface of the stationary member, causing the engagement element to frictionally engage with the stationary member. As a result, the eccentric shaft cannot rotate any further, and the output shaft is locked.

[0022] When rotation is subsequently input to the input shaft, the engaging element pressing portion rotates integrally with the input shaft, and the engaging element pressing portion presses the engaging element, which is forward in the direction of rotation relative to the narrow portion of the eccentric space, toward the wide portion of the eccentric space, thereby releasing the frictional engagement of the engaging element with the stationary member and unlocking the output shaft.As the input shaft rotates further and the circumferential play between the input-side transmission part and the output-side transmission part disappears, the eccentric shaft part rotates integrally with the input shaft, and the output shaft also rotates integrally.

[0023] Here, the outer peripheral engagement surface of the engaging element is formed in a partially cylindrical shape that extends along the cylindrical inner peripheral surface of the stationary member, and the output shaft is locked by frictional engagement of the outer peripheral engagement surface of the engaging element, so the contact surface pressure of the engaging element is lower and the locking operation of the output shaft is gentler than when the output shaft is locked by roller engagement. Similarly, the output shaft is unlocked by releasing the frictional engagement of the outer peripheral engagement surface of the engaging element, so the unlocking operation of the output shaft is gentler than when the output shaft is unlocked by releasing the roller engagement. Therefore, when a reverse input prevention clutch of this configuration is used in an actuator for a continuously variable transmission, the axial movement of the movable sheave is smoother and does not become an intermittent operation that repeatedly involves sudden movements and stops, and abnormal noise is less likely to occur.

[0024] [Configuration 2] The reverse input prevention clutch according to configuration 1, wherein the pair of engaging elements further have a partially cylindrical inner engaging surface having a center eccentric to the center of the outer engaging surface so as to follow the cylindrical outer peripheral surface of the eccentric shaft portion.

[0025] In this configuration, the inner engaging surface of the engaging element is formed in a partially cylindrical shape with its center eccentric from the center of the outer engaging surface so as to fit along the cylindrical outer surface of the eccentric shaft, thereby reducing the gap between the eccentric shaft and the engaging element.As a result, when rotation is input to the output shaft, the time required for the engaging element to frictionally engage with the stationary member can be minimized, resulting in high responsiveness.

[0026] Furthermore, since the inner engagement surface of the engaging element is partially cylindrical and conforms to the cylindrical outer surface of the eccentric shaft, the locking and unlocking operations of the output shaft are performed by frictional engagement and release of that frictional engagement between the inner engagement surface of the engaging element and the cylindrical outer surface of the eccentric shaft, making them gentler.

[0027] [Configuration 3] A reverse input prevention clutch according to either of configurations 1 or 2, wherein one of the input side transmission portion and the output side transmission portion is a convex portion formed to protrude in the axial direction, and the other is a concave portion having an elongated hole shape that is long in the circumferential direction.

[0028] [Configuration 4] 4. The reverse input prevention clutch according to any one of configurations 1 to 3, wherein the engaging element pressing portion is formed in a circular arc shape that continues in the circumferential direction from an end face on one circumferential side to an end face on the other circumferential side.

[0029] In this configuration, the engaging element pressing portion is formed in a circular arc shape that continues in the circumferential direction, so that the engaging element pressing portion is less likely to deform when it presses the engaging element in the circumferential direction, making it easier to ensure the strength of the engaging element pressing portion.

[0030] [Configuration 5] A reverse input prevention clutch according to any one of configurations 1 to 4, wherein the stationary member is composed of an annular outer ring member having the cylindrical inner circumferential surface and a housing that accommodates the outer ring member.

[0031] In this configuration, the stationary member is composed of an outer ring member having a cylindrical inner peripheral surface and a housing that accommodates the outer ring member, and since the member having the cylindrical inner peripheral surface is small, it is easy to process the cylindrical inner peripheral surface.

[0032] The present invention also provides an actuator for a continuously variable transmission equipped with the reverse input prevention clutch having the above-described configuration, which has the following configuration. [Configuration 6] an electric motor that outputs rotation; a rotation transmission path that transmits rotation output from the electric motor; a motion conversion mechanism that converts the rotation transmitted from the electric motor via the rotation transmission path into axial movement of a movable sheave that is disposed opposite a fixed sheave of a belt-type continuously variable transmission; and the reverse input prevention clutch according to any one of configurations 1 to 5, which is incorporated in the rotation transmission path so as to allow transmission of rotation from the electric motor side to the movable sheave side and prevent transmission of rotation from the movable sheave side to the electric motor side. [Effects of the Invention]

[0033] In this reverse input prevention clutch, the outer peripheral engagement surface of the engagement element is formed in a partially cylindrical shape that extends along the cylindrical inner peripheral surface of the stationary member, and the output shaft is locked by frictional engagement of the outer peripheral engagement surface of the engagement element, so the contact surface pressure of the engagement element is lower and the locking operation of the output shaft is gentler than when the output shaft is locked by roller engagement. Similarly, the output shaft is unlocked by releasing the frictional engagement of the outer peripheral engagement surface of the engagement element, so the unlocking operation of the output shaft is gentler than when the output shaft is unlocked by releasing the roller engagement. Therefore, when a reverse input prevention clutch of this configuration is used in an actuator for a continuously variable transmission, the movable sheave moves smoothly and is less likely to generate abnormal noise when it is axially moved away from the fixed sheave. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a longitudinal sectional view of a reverse input prevention clutch according to a first embodiment; [Figure 2] Cross-sectional view along line II-II in Figure 1 [Figure 3] A cross-sectional view illustrating the operation when rotation is input to the input shaft shown in Figure 2. [Figure 4] Cross-sectional view of the actuator for a continuously variable transmission incorporating the reverse input prevention clutch shown in Figure 1 [Figure 5] Enlarged view of the reverse input prevention clutch area in Figure 4 [Figure 6] FIG. 10 is a longitudinal sectional view of a reverse input prevention clutch according to a second embodiment; [Figure 7] Cross-sectional view taken along line VII-VII in Figure 6 [Figure 8] 7 is a diagram showing an actuator for a continuously variable transmission incorporating the reverse input prevention clutch of FIG. 6, corresponding to FIG. 5; [Figure 9] FIG. 5 is a diagram corresponding to FIG. 4 showing an actuator for a continuously variable transmission in which the output shaft of a reverse input prevention clutch is supported by a plurality of output-side bearings. DETAILED DESCRIPTION OF THE INVENTION

[0035] [First embodiment] 1 and 2 show a reverse input prevention clutch according to a first embodiment of the present invention. This reverse input prevention clutch includes an input shaft 1, a housing 2, an output shaft 4 having an eccentric shaft portion 3, an eccentric space 5 formed between the eccentric shaft portion 3 and the housing 2, an engaging element pressing portion 6 connected to the input shaft 1, an input side transmission portion 7 provided on the input shaft 1, an output side transmission portion 8 provided on the output shaft 4, a pair of engaging elements 9a, 9b (see FIG. 2) incorporated in the eccentric space 5, and an elastic member 10 provided between the pair of engaging elements 9a, 9b.

[0036] As shown in Figure 1, the housing 2 has a cylindrical inner circumferential surface 11 formed in a cylindrical shape with a constant inner diameter along the axial direction. The input shaft 1 is rotatably supported by an input-side bearing 12 incorporated into the inner periphery of the housing 2. The center of rotation C0 of the input shaft 1 is at the same position as the center of the cylindrical inner circumferential surface 11 of the housing 2. The housing 2 is a stationary member that is fixed so as not to rotate.

[0037] The output shaft 4 is rotatably supported by an output-side bearing 13 incorporated into the inner periphery of the housing 2. The output shaft 4 has a rotation center at the same position as the rotation center C0 of the input shaft 1. The input shaft 1 and the output shaft 4 are arranged side by side in the axial direction so that an end face 14 of the input shaft 1 and an end face 15 of the output shaft 4 face each other with a gap between them. The output shaft 4 has an eccentric shaft portion 3 at the end on the input shaft 1 side.

[0038] As shown in FIG. 2, the eccentric shaft portion 3 has a cylindrical outer peripheral surface 16 that is eccentric with respect to the center of rotation C0 of the input shaft 1. The cylindrical outer peripheral surface 16 is formed in a cylindrical shape with a center C1 that is eccentric in a predetermined direction (upward in the figure; hereinafter referred to as the "eccentric direction") with respect to the center of rotation C0 of the input shaft 1. The cylindrical outer peripheral surface 16 is formed in a cylindrical shape with a constant outer diameter along the axial direction. The cylindrical outer peripheral surface 16 of the eccentric shaft portion 3 has an outer diameter that is at least half the inner diameter of the cylindrical inner peripheral surface 11 of the housing 2. The amount of eccentricity of the center C1 of the cylindrical outer peripheral surface 16 of the eccentric shaft portion 3 from the center of rotation C0 of the input shaft 1 is set in the range of 1.0% to 5.0% of the inner diameter of the cylindrical inner peripheral surface 11 of the housing 2.

[0039] The eccentric space 5 is an annular space formed between the cylindrical inner peripheral surface 11 of the housing 2 and the cylindrical outer peripheral surface 16 of the eccentric shaft portion 3. The eccentric space 5 has a narrow portion 17 located in the eccentric direction of the eccentric shaft portion 3 (upward in the figure), a wide portion 18 located in the opposite direction to the eccentric direction of the eccentric shaft portion 3 (downward in the figure), and a pair of arc-shaped spaces 19a, 19b formed between the narrow portion 17 and the wide portion 18. The radial widths of the pair of arc-shaped spaces 19a, 19b gradually increase from the narrow portion 17 to the wide portion 18. In other words, the eccentric space 5 is formed so that the radial width gradually increases from the narrow portion 17 to the wide portion 18. The narrow portion 17, the arc-shaped space 19a, the wide portion 18, and the arc-shaped space 19b are connected in this order in the circumferential direction, and the arc-shaped space 19b is further connected to the narrow portion 17.

[0040] 1, the engaging element pressing portion 6 is connected to the end of the input shaft 1 so as to move circumferentially integrally with the input shaft 1. In FIG. 1, the engaging element pressing portion 6 is formed integrally with the input shaft 1, but the engaging element pressing portion 6 may be formed separately from the input shaft 1 and fixed to the input shaft 1.

[0041] As shown in FIG. 2, the engaging element pressing portion 6 is disposed in the narrow portion 17 of the eccentric space 5. The engaging element pressing portion 6 is formed in an arc shape that continues uninterrupted in the circumferential direction from an end face 20a on one circumferential side of the engaging element pressing portion 6 to an end face 20b on the other circumferential side of the engaging element pressing portion 6. The outer peripheral surface 21 of the engaging element pressing portion 6 extends along the cylindrical inner peripheral surface 11 of the housing 2 and is formed in a partial cylindrical shape with its center at a position corresponding to the center of the cylindrical inner peripheral surface 11 of the housing 2 (i.e., the rotation center C0 of the input shaft 1). The inner peripheral surface 22 of the engaging element pressing portion 6 is formed in a partial cylindrical shape with its center at the same position as the center of the outer peripheral surface 21 of the engaging element pressing portion 6, thereby making the radial thickness of the engaging element pressing portion 6 constant along the circumferential direction.

[0042] The outer peripheral surface 21 of the engaging element pressing portion 6 does not contact the cylindrical inner peripheral surface 11 of the housing 2, and the inner peripheral surface 22 of the engaging element pressing portion 6 does not contact the cylindrical outer peripheral surface 16 of the eccentric shaft portion 3. A constant radial gap whose radial width does not change along the circumferential direction is provided between the outer peripheral surface 21 of the engaging element pressing portion 6 and the cylindrical inner peripheral surface 11 of the housing 2. A radial gap whose radial width gradually increases from the circumferential center toward both sides in the circumferential direction is provided between the inner peripheral surface 22 of the engaging element pressing portion 6 and the cylindrical outer peripheral surface 16 of the eccentric shaft portion 3.

[0043] The pair of engaging elements 9a, 9b consists of the engaging element 9a on one circumferential side (the right side in the figure) of the narrow portion 17 and the engaging element 9b on the other circumferential side (the left side in the figure). The engaging element 9a is housed in an arc-shaped space 19a on one circumferential side (the right side in the figure) of the narrow portion 17 of the eccentric space 5. The engaging element 9b is housed in an arc-shaped space 19b on the other circumferential side (the left side in the figure) of the narrow portion 17 of the eccentric space 5. The engaging elements 9a, 9b have an outer peripheral engaging surface 23 extending along the cylindrical inner peripheral surface 11 of the housing 2 and an inner peripheral engaging surface 24 extending along the cylindrical outer peripheral surface 16 of the eccentric shaft portion 3.

[0044] The inner engagement surfaces 24 of the engaging elements 9a, 9b have centers eccentric to the centers of the outer engagement surfaces 23 of the engaging elements 9a, 9b. That is, the inner engagement surfaces 24 and the outer engagement surfaces 23 of the engaging elements 9a, 9b are cylindrical surfaces with centers at different positions, and the centers of the inner engagement surfaces 24 and the outer engagement surfaces 23 of the engaging elements 9a, 9b do not coincide. The outer engagement surfaces 23 are partially cylindrical surfaces with their centers corresponding to the center of the cylindrical inner circumferential surface 11 of the housing 2 (i.e., the rotation center C0 of the input shaft 1). The inner engagement surface 24 is partially cylindrical surfaces with their centers corresponding to the center C1 of the cylindrical outer circumferential surface 16 of the eccentric shaft portion 3. The radius of curvature of the outer engagement surface 23 is set to be 95% or more (preferably 97% or more) but less than 100% of the radius of the cylindrical inner circumferential surface 11 of the housing 2. The radius of curvature of the inner peripheral engaging surface 24 is set to be more than 100% of the radius of the cylindrical outer peripheral surface 16 of the eccentric shaft portion 3 and not more than 105% (preferably not more than 103%).

[0045] The engaging element 9a faces, with a circumferential play, an end face 20a on one circumferential side (the right side in the drawing) of the engaging element pressing portion 6. The engaging element 9b faces, with a circumferential play, an end face 20b on the other circumferential side (the left side in the drawing) of the engaging element pressing portion 6. The play between the pair of engaging elements 9a, 9b and the end faces 20a, 20b on both circumferential sides of the engaging element pressing portion 6 may be eliminated, and the pair of engaging elements 9a, 9b may be brought into contact with the end faces 20a, 20b on both circumferential sides of the engaging element pressing portion 6.

[0046] Corners 25a at both circumferential ends of the outer engagement surface 23 of each of the engaging elements 9a, 9b are R-chamfered. In addition, corners 25b at the ends of the inner engagement surface 24 of each of the engaging elements 9a, 9b that are closer to the engaging element pressing portion 6 are also R-chamfered. Similarly, corners 25c at the ends of the inner engagement surface 24 of each of the engaging elements 9a, 9b that are farther from the engaging element pressing portion 6 are also R-chamfered.

[0047] The elastic member 10 is disposed in the wide portion 18 of the eccentric space 5. One circumferential end of the elastic member 10 contacts the end faces of the engaging elements 9a, 9b opposite to the sides facing the engaging element pressing portions 6, and the other circumferential end of the elastic member 10 contacts the end faces of the engaging elements 9a, 9b opposite to the sides facing the engaging element pressing portions 6. The elastic member 10 is compressed between the pair of engaging elements 9a, 9b, and urges the pair of engaging elements 9a, 9b in directions separating them from each other by its elastic restoring force. The outer circumferential engaging surfaces 23 of the pair of engaging elements 9a, 9b are pressed against the cylindrical inner circumferential surface 11 of the housing 2 by the force of the elastic member 10. The elastic member 10 can be, for example, a metal spring (such as a coil spring).

[0048] As shown in Fig. 1, the input-side transmission part 7 is provided on an end face 14 of the input shaft 1 so as to rotate integrally with the input shaft 1. In the drawing, the input-side transmission part 7 is a convex part formed to protrude in the axial direction from the end face 14 of the input shaft 1. As shown in Fig. 2, the input-side transmission part 7 is provided at a position radially displaced from the rotation center C0 of the input shaft 1 so as to move circumferentially in conjunction with the rotation of the input shaft 1 when the input shaft 1 rotates.

[0049] As shown in FIG. 1, the output-side transmission part 8 is provided on the end surface 15 of the output shaft 4 so as to rotate integrally with the output shaft 4. In the figure, the output-side transmission part 8 is a recess provided on the end surface 15 of the output shaft 4. As shown in FIG. 2, the output-side transmission part 8 engages with the input-side transmission part 7 with circumferential play. In the figure, the output-side transmission part 8 has the shape of an elongated hole that is long in the circumferential direction and is provided at a position radially offset from the rotation center C0 of the input shaft 1.

[0050] When the input shaft 1 rotates, the input side transmission part 7 and the output side transmission part 8 do not come into contact with the output side transmission part 8 within the range of circumferential play between the input side transmission part 7 and the output side transmission part 8, and the rotation of the input shaft 1 is not transmitted to the output shaft 4. When the input shaft 1 further rotates and the circumferential play between the input side transmission part 7 and the output side transmission part 8 is eliminated, the input side transmission part 7 comes into contact with the output side transmission part 8, and the rotation of the input shaft 1 is transmitted to the output shaft 4 via this contact part, causing the output shaft 4 to rotate integrally with the input shaft 1.

[0051] The magnitude of the circumferential play between the input side transmission part 7 and the output side transmission part 8 is set so that when the input shaft 1 rotates and the engaging part pressing part 6, which moves circumferentially together with the input shaft 1, comes into contact with the engaging parts 9a, 9b, the input side transmission part 7, which moves circumferentially together with the input shaft 1, does not yet come into contact with the output side transmission part 8, and circumferential play remains.

[0052] Here, as shown in Figure 1, an example has been explained in which the input side transmission section 7 is a convex section and the output side transmission section 8 is a concave section, but the input side transmission section 7 may also be a concave section and the output side transmission section 8 may be a convex section.

[0053] 4 shows an actuator for a continuously variable transmission equipped with the above-described reverse input prevention clutch 26. This actuator for a continuously variable transmission is an actuator that moves a movable sheave 29 of a belt-type continuously variable transmission in the axial direction.

[0054] The belt-type continuously variable transmission includes a drive pulley 27, a driven pulley (not shown), and a transmission belt 28 wound between the drive pulley 27 and the driven pulley. The drive pulley 27 is configured with a movable sheave 29 and a fixed sheave 30 that face each other in the axial direction. A V-groove 31, around which the transmission belt 28 is wound, is formed between the movable sheave 29 and the fixed sheave 30. That is, one of the slopes of the V-groove 31 is formed in the movable sheave 29, and the other slope of the V-groove 31 is formed in the fixed sheave 30. By moving the movable sheave 29 in the axial direction, the width of the V-groove 31 can be changed. An actuator that moves the movable sheave 29 in the axial direction is attached to the movable sheave 29. The driven pulley (not shown) is configured similarly to the drive pulley 27.

[0055] In this belt-type continuously variable transmission, when the movable sheave 29 is moved axially by the continuously variable transmission actuator, the width of the V-groove 31 between the movable sheave 29 and the fixed sheave 30 changes, making it possible to continuously change the winding diameter of the transmission belt 28 around the drive pulley 27. Similarly, the winding diameter of the drive pulley (not shown) can also be continuously changed. This continuously changes the ratio of the winding diameter of the drive pulley 27 to the winding diameter of the driven pulley, thereby continuously adjusting the speed ratio.

[0056] This continuously variable transmission actuator has an electric motor 32 that outputs rotation, a rotation transmission path 33 that transmits the rotation output from the electric motor 32, and a motion conversion mechanism 34 that converts the rotation transmitted from the electric motor 32 via the rotation transmission path 33 into axial movement. A reverse input prevention clutch 26 is incorporated into the rotation transmission path 33. The reverse input prevention clutch 26 is a mechanism that allows the transmission of rotation from the electric motor 32 side to the movable sheave 29 side and prevents the transmission of rotation from the movable sheave 29 side to the electric motor 32 side.

[0057] The electric motor 32 has a motor output shaft 35 and a motor body 36 that rotates the motor output shaft 35. The motor body 36 is fixed to the housing 2. The rotation output by the motor body 36 is transmitted from the motor output shaft 35 to the rotation transmission path 33.

[0058] The rotation transmission path 33 includes, in order from the electric motor 32 side toward the motion conversion mechanism 34 side, a first gear 37, a second gear 38, the reverse input prevention clutch 26, a third gear 39, and a fourth gear 40. The first gear 37 is fixed to the motor output shaft 35 and meshes with a second gear 38 fixed to the input shaft 1 of the reverse input prevention clutch 26. As a result, the rotation of the motor is input to the reverse input prevention clutch 26 via the first gear 37 and the second gear 38 in this order. The first gear 37 and the second gear 38 are arranged in parallel. The number of teeth of the second gear 38 is set to be greater than the number of teeth of the first gear 37, so that the rotation of the motor output shaft 35 is transmitted to the input shaft 1 of the reverse input prevention clutch 26 at a reduced speed.

[0059] The third gear 39 is fixed to the output shaft 4 of the reverse input prevention clutch 26, and the third gear 39 meshes with a fourth gear 40 provided on a nut member 42 of the motion conversion mechanism 34. As a result, the rotation output from the reverse input prevention clutch 26 is input to the motion conversion mechanism 34 via the third gear 39 and then the fourth gear 40. The third gear 39 and the fourth gear 40 are arranged in parallel. The number of teeth of the fourth gear 40 is set to be greater than the number of teeth of the third gear 39, so that the rotation of the output shaft 4 of the reverse input prevention clutch 26 is transmitted to the motion conversion mechanism 34 at a reduced speed. The third gear 39 has an axial width dimension greater than the axial width dimension of the fourth gear 40 so that the third gear 39 maintains meshing with the fourth gear 40 even when the fourth gear 40 moves axially relative to the third gear 39.

[0060] In the figure, the motion converting mechanism 34 is a so-called ball screw mechanism, and includes a screw shaft 41, a nut member 42, and a plurality of balls 43. The balls 43 are in rolling contact with a helical male thread groove 44a formed on the outer periphery of the screw shaft 41 and a helical female thread groove 44b formed on the inner periphery of the nut member 42. The screw shaft 41 and the nut member 42 are threadedly engaged via the balls 43. When the nut member 42 rotates relative to the screw shaft 41, the nut member 42 moves in the axial direction relative to the screw shaft 41. The motion converting mechanism 34 may use a sliding screw mechanism, instead of the balls 43, in which the thread on the outer periphery of the screw shaft 41 and the thread groove on the inner periphery of the nut member 42 are in sliding contact with each other.

[0061] The nut member 42 is provided with a fourth gear 40, and when the fourth gear 40 rotates, the nut member 42 rotates integrally with the fourth gear 40. The screw shaft 41 is fixed to the housing 2 so as not to move or rotate in the axial direction relative to the housing 2. A rolling bearing 45 is incorporated between the nut member 42 and the movable sheave 29. The rolling bearing 45 connects the nut member 42 and the movable sheave 29 so that the rotation of the movable sheave 29 is not transmitted to the nut member 42. In addition, the nut member 42 is connected to the movable sheave 29 via the rolling bearing 45 so that when the nut member 42 moves in the axial direction, the movable sheave 29 moves axially integrally with the nut member 42.

[0062] In this motion converting mechanism 34, when the fourth gear 40 rotates, the nut member 42 rotates integrally with the fourth gear 40. Here, the screw shaft 41 is prevented from rotating relative to the housing 2 and its axial movement is restricted, so the nut member 42 moves axially, and the movable sheave 29 also moves axially integrally with the nut member 42.

[0063] The fixed sheave 30 has a sheave body 46 on which the slope of the V-groove 31 is formed, and a sheave shaft 47 extending in the axial direction from the sheave body 46. The sheave shaft 47 is rotatably supported by a rolling bearing 48 incorporated in the housing 2.

[0064] The movable sheave 29 is disposed opposite a sheave body 46 of the fixed sheave 30. The movable sheave 29 is formed in an annular shape, and the outer periphery of a sheave shaft 47 is fitted onto the inner periphery of the movable sheave 29. The fitting portion between the movable sheave 29 and the sheave shaft 47 is provided with a rotation preventing portion 49 (for example, a spline protrusion and a spline groove) that prevents the movable sheave 29 from rotating relative to the sheave shaft 47 while allowing the movable sheave 29 to move axially relative to the sheave shaft 47.

[0065] In the above-described belt-type continuously variable transmission, the axial position of the movable sheave 29 needs to be maintained against the axial component of the force received from the transmission belt 28. That is, the movable sheave 29 and the fixed sheave 30 receive a force in the radially inward direction from the transmission belt 28 wound around the V-groove 31. Here, an axial component of force in a direction away from the fixed sheave 30 (to the left in the drawing) acts on the slope of the V-groove 31 of the movable sheave 29. Therefore, unless the axial position of the movable sheave 29 is maintained by some method, the movable sheave 29 will move in the axial direction, and the width of the V-groove 31 between the movable sheave 29 and the fixed sheave 30 will change.

[0066] Therefore, one possible method for maintaining the axial position of the movable sheave 29 is to use the torque generated by the electric motor 32. That is, torque is generated by the electric motor 32, and this torque is transmitted to the movable sheave 29 as an axial force via the rotation transmission path 33 and the motion conversion mechanism 34. This axial force is used to cancel out the axial component of the force received from the transmission belt 28, thereby preventing the movable sheave 29 from moving in the axial direction and maintaining the width of the V-groove 31.

[0067] However, if the axial position of the movable sheave 29 is maintained by the torque of the electric motor 32, it is necessary to supply power to the electric motor 32 not only when the axial position of the movable sheave 29 is moved to change the winding diameter of the transmission belt 28, but also at all times while the axial position of the movable sheave 29 is maintained without movement.Furthermore, the electric motor 32 must be made larger in order to ensure torque sufficient to prevent axial movement of the movable sheave 29.

[0068] Therefore, in this embodiment, in order to maintain the axial position of the movable sheave 29, a reverse input prevention clutch 26 is incorporated into the rotation transmission path 33 to prevent transmission of rotation from the movable sheave 29 to the electric motor 32. That is, even if an axial component force acts from the transmission belt 28 on the slope of the V-groove 31 of the movable sheave 29 and the axial component force is converted into a rotational force by the motion conversion mechanism 34 and input into the rotation transmission path 33, the reverse input prevention clutch 26 (see FIG. 5) prevents rotation due to the rotational force, thereby preventing axial movement of the movable sheave 29.

[0069] Incidentally, in conventional reverse input prevention clutches that employ a method of locking the output shaft by engaging rollers or balls between the outer peripheral surface of the output shaft and the inner peripheral surface of the housing, the action of locking the output shaft (the action of preventing the output shaft from rotating) is a sudden action caused by the rollers or balls becoming engaged, and the action of unlocking the output shaft is also a sudden action caused by the rollers or balls becoming disengaged.

[0070] Therefore, if this conventional reverse input prevention clutch is assumed to be incorporated at the position of reverse input prevention clutch 26 in rotation transmission path 33 shown in Figure 4, there is a problem that when moving movable sheave 29 in the axial direction, it sometimes cannot be moved smoothly.

[0071] Furthermore, if a conventional reverse input prevention clutch that engages rollers or balls is incorporated at the position of reverse input prevention clutch 26 in rotation transmission path 33 shown in Figure 4, the rollers or balls will engage with high surface pressure, which could cause abnormal noise when the rollers or balls of the reverse input prevention clutch disengage. Therefore, when the locking and unlocking operations of output shaft 4 are repeated, abnormal noise will be generated repeatedly, which could cause discomfort to the user.

[0072] To address this problem, this embodiment employs a reverse input prevention clutch 26 that provides a gradual locking and unlocking action for the output shaft 4 when rotation is input to the output shaft 4, thereby enabling smooth axial movement of the movable sheave 29.

[0073] 2, when rotation is input to the output shaft 4, the eccentric shaft portion 3 attempts to rotate integrally with the output shaft 4. However, the cylindrical outer peripheral surface 16 of the eccentric shaft portion 3 immediately presses the engagement element 9a, which is on the front side in the direction of rotation, against the narrow portion 17 of the eccentric space 5, so that the partially cylindrical outer peripheral engagement surface 23 of the engagement element 9a is pressed against the cylindrical inner peripheral surface 11 of the housing 2, and the engagement element 9a frictionally engages with the housing 2. As a result, the eccentric shaft portion 3 cannot rotate any further, and the output shaft 4 is locked.

[0074] 3, when rotation is input to the input shaft 1, the engaging element pressing portion 6 rotates integrally with the input shaft 1, and the engaging element pressing portion 6 presses the engaging element 9a, which is on the front side in the direction of rotation relative to the narrow portion 17 of the eccentric space 5, toward the wide portion 18 of the eccentric space 5, thereby releasing the frictional engagement of the engaging element 9a with the housing 2 and unlocking the output shaft 4. When the input shaft 1 continues to rotate and there is no circumferential play between the input side transmission portion 7 and the output side transmission portion 8, the eccentric shaft portion 3 rotates integrally with the input shaft 1, and the output shaft 4 also rotates integrally.

[0075] 2, outer peripheral engagement surfaces 23 of the engagement elements 9a, 9b are formed in a partially cylindrical shape extending along the cylindrical inner peripheral surface 11 of the housing 2, and the output shaft 4 is locked by frictional engagement of the outer peripheral engagement surfaces 23 of the engagement elements 9a, 9b. This results in a lower contact surface pressure between the engagement elements 9a, 9b and a gentler locking action of the output shaft 4 compared to when the output shaft is locked by roller engagement. Similarly, the output shaft 4 is unlocked by releasing the frictional engagement of the outer peripheral engagement surfaces 23 of the engagement elements 9a, 9b, and therefore the unlocking action of the output shaft 4 is gentler compared to when the output shaft 4 is unlocked by releasing the roller engagement. Therefore, when the reverse input prevention clutch 26 having this configuration is used in an actuator for a continuously variable transmission, the axial movement of the movable sheave 29 is smoother and does not undergo intermittent movements that repeatedly involve sudden movements and stops, and abnormal noise is less likely to occur.

[0076] Furthermore, the inner peripheral engagement surface 24 of the engagement members 9a, 9b is formed in a partially cylindrical shape with its center eccentric from the center of the outer peripheral engagement surface 23 so as to fit along the cylindrical outer peripheral surface 16 of the eccentric shaft portion 3, so that the gap between the eccentric shaft portion 3 and the engagement members 9a, 9b is small. Therefore, when rotation is input to the output shaft 4, the time required for the engagement members 9a, 9b to frictionally engage with the housing 2 can be minimized, and high responsiveness can be achieved.

[0077] Furthermore, since the inner engagement surfaces 24 of the engaging elements 9a, 9b are partially cylindrical and conform to the cylindrical outer surface 16 of the eccentric shaft portion 3, the locking and unlocking operations of the output shaft 4 are performed by frictional engagement and release of that frictional engagement between the inner engagement surfaces 24 of the engaging elements 9a, 9b and the cylindrical outer surface 16 of the eccentric shaft portion 3, making them gentler.

[0078] Furthermore, since the engaging element pressing portion 6 is formed in a circular arc shape that continues in the circumferential direction, the engaging element pressing portion 6 is less likely to deform when it presses the engaging elements 9a, 9b in the circumferential direction, and the strength of the engaging element pressing portion 6 can be easily ensured.

[0079] Here, as shown in Figure 4, an example has been described in which only one axial end of the output shaft 4 (the right side in the figure) is supported by the output side bearing 13 out of both axial ends of the output shaft 4, but as shown in Figure 9, the output shaft 4 may also be supported by a plurality of output side bearings 13 arranged at intervals in the axial direction.

[0080] [Second embodiment] 6 and 7 show a reverse input preventing clutch according to a second embodiment of the present invention. This reverse input preventing clutch differs from the first embodiment only in that the stationary member having the cylindrical inner peripheral surface 11 with which the engaging elements 9a and 9b engage is composed of an outer ring member 50, a housing 2 that accommodates the outer ring member 50, and a pin 51. That is, in the first embodiment, the stationary member having the cylindrical inner peripheral surface 11 with which the engaging elements 9a and 9b engage is the housing 2, and the housing 2 is machined to have the cylindrical inner peripheral surface 11. In the second embodiment, the stationary member having the cylindrical inner peripheral surface 11 with which the engaging elements 9a and 9b engage is composed of the outer ring member 50, a housing 2 that accommodates the outer ring member 50, and a pin 51, and the outer ring member 50 is machined to have the cylindrical inner peripheral surface 11 with which the engaging elements 9a and 9b engage. The rest of the configuration is the same as in the first embodiment. Therefore, parts corresponding to those in the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted.

[0081] As shown in FIG. 7, the outer ring member 50 is an annular member. The cylindrical inner peripheral surface 11 of the outer ring member 50 is formed into a cylindrical shape with a constant inner diameter along the axial direction. The cylindrical outer peripheral surface of the outer ring member 50 is formed into a cylindrical shape with a constant outer diameter along the axial direction. The center of the cylindrical inner peripheral surface 11 of the outer ring member 50 is located at the same position as the rotation center C0 of the input shaft 1. The outer ring member 50 has a through hole 52 that penetrates in the radial direction.

[0082] The housing 2 has a cylindrical inner peripheral surface 53 that fits along the cylindrical outer peripheral surface of the outer ring member 50. A through hole 54 that penetrates radially and has the same diameter as the through hole 52 of the outer ring member 50 is provided in the cylindrical inner peripheral surface 53. The outer ring member 50 is disposed inside the cylindrical inner peripheral surface 53. A pin 51 is fitted into the through hole 54 of the housing 2 and the through hole 52 of the outer ring member 50, fixing the outer ring member 50 to the housing 2 so as not to rotate. As shown in FIG. 6 , an input-side bearing 12 that rotatably supports the input shaft 1 is incorporated into the housing 2. An output-side bearing 13 that rotatably supports the output shaft 4 is also incorporated into the housing 2.

[0083] The outer ring member 50 may be fixed to the housing 2 using other fixing means such as bolts instead of the pins 51.

[0084] In the reverse input prevention clutch of this second embodiment, the stationary member having the cylindrical inner peripheral surface 11 is composed of an outer ring member 50 and a housing 2 that accommodates the outer ring member 50, and since the member having the cylindrical inner peripheral surface 11 (i.e., the outer ring member 50) is small, it is easy to process the cylindrical inner peripheral surface 11. Other functions and effects are the same as those of the first embodiment.

[0085] As shown in FIG. 8, the reverse input prevention clutch 26 of the second embodiment can also be used in an actuator for a continuously variable transmission, similar to the reverse input prevention clutch of the first embodiment.

[0086] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0087] 1 input shaft 2. Housing 3 Eccentric shaft part 4 output shaft 5 Eccentric space 6. Engagement element pressing part 7 Input side transmission section 8 Output side transmission section 9a,9b Engagement element 10 Elastic member 11 Cylindrical inner surface of stationary member 16 Cylindrical outer surface of eccentric shaft 17 Narrow area 18 Hiroshima University 19a, 19b Arc-shaped space 20a, 20b End faces of the engaging element pressing portions 23 Outer circumferential engagement surface 24 Inner engagement surface 26 Reverse input prevention clutch 29 Movable sheave 30 Fixed sheave 32 Electric motor 33 Rotation transmission path 34 Motion conversion mechanism 50 outer ring member C0 Center of rotation of input shaft C1 Center of the cylindrical outer surface of the eccentric shaft

Claims

1. an input shaft (1) to which rotation is input; an output shaft (4) having an eccentric shaft portion (3) with a cylindrical outer peripheral surface (16) formed on its outer periphery, the cylindrical outer peripheral surface (16) having a center (C1) eccentric to the rotation center (C0) of the input shaft (1), and supported rotatably around the same position as the rotation center (C0) of the input shaft (1); a stationary member having a cylindrical inner peripheral surface (11) formed in a cylindrical shape centered on the rotation center (C0) of the input shaft (1); an annular eccentric space (5) formed between the cylindrical inner peripheral surface (11) and the cylindrical outer peripheral surface (16), the radial width of which gradually increases from a narrow portion (17) located in the eccentric direction of the eccentric shaft portion (3) toward a wide portion (18) located in the opposite direction to the eccentric direction of the eccentric shaft portion (3); an engaging element pressing portion (6) disposed in the narrow portion (17) of the eccentric space (5) and coupled to the input shaft (1) so as to move integrally with the input shaft (1) in a circumferential direction; an input-side transmission portion (7) provided on the input shaft (1) so as to rotate integrally with the input shaft (1); an output-side transmission part (8) provided on the output shaft (4) so ​​as to rotate integrally with the output shaft (4), and engaging with the input-side transmission part (7) with circumferential play; a pair of engaging pieces (9a, 9b) accommodated in a pair of arc-shaped spaces (19a, 19b) formed between the narrow portion (17) and the wide portion (18) of the eccentric space (5) and facing end faces (20a, 20b) on both sides in the circumferential direction of the engaging piece pressing portion (6); The pair of engaging elements (9a, 9b) each have a partially cylindrical outer engaging surface (23) extending along the cylindrical inner peripheral surface (11) of the stationary member, A reverse input prevention clutch is provided with an elastic member (10) that biases the pair of engaging elements (9a, 9b) so as to press the outer engaging surfaces (23) of the pair of engaging elements (9a, 9b) against the cylindrical inner peripheral surface (11).

2. 2. The reverse input prevention clutch according to claim 1, wherein the pair of engaging elements (9 a, 9 b) further have a partially cylindrical inner engaging surface (24) having a center eccentric to the center of the outer engaging surface (23) so as to follow the cylindrical outer circumferential surface (16) of the eccentric shaft portion (3).

3. 2. A reverse input prevention clutch according to claim 1, wherein one of the input side transmission portion (7) and the output side transmission portion (8) is a convex portion formed to protrude in the axial direction, and the other is a concave portion shaped like a long hole that is elongated in the circumferential direction.

4. 2. The reverse input prevention clutch according to claim 1, wherein the engaging element pressing portion (6) is formed in a circular arc shape that continues in the circumferential direction from an end face (20a) on one circumferential side to an end face (20b) on the other circumferential side.

5. 2. The reverse input prevention clutch according to claim 1, wherein the stationary member is composed of an annular outer ring member (50) having the cylindrical inner peripheral surface (11) and a housing (2) that accommodates the outer ring member (50).

6. an electric motor (32) that outputs rotation; a rotation transmission path (33) for transmitting rotation output from the electric motor (32); a motion conversion mechanism (34) that converts the rotation transmitted from the electric motor (32) via the rotation transmission path (33) into axial movement of a movable sheave (29) that is disposed opposite the fixed sheave (30) of the belt-type continuously variable transmission; and a reverse input prevention clutch (26) according to any one of claims 1 to 5, which is incorporated into the rotation transmission path (33) so as to allow transmission of rotation from the electric motor (32) side to the movable sheave (29) side and prevent transmission of rotation from the movable sheave (29) side to the electric motor (32) side.

Images