Reverse input prevention clutch and actuator for continuously variable transmission

Abstract

To provide a reverse input prevention clutch with gradual locking and unlocking of an output shaft.SOLUTION: A reverse input prevention clutch comprises: an input shaft 2; an output shaft 3; a fixed outer ring 4 with an inner peripheral friction surface 7; a split outer ring 5 frictionally engaging with the inner peripheral friction surface 7; and one-side rollers 6a and the other-side rollers 6b incorporated between the inner periphery of the split outer ring 5 and the outer periphery of the output shaft 3. A one-side cam surface 11a and the other-side cam surface 11b are formed on the outer periphery of the output shaft 3. A one-side roller pressing part 13a and the other-side roller pressing part 13b are provided on the input shaft 2. A free play coupling part 14 is provided between the input shaft 2 and the output shaft 3.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a reverse input prevention clutch and an actuator for a continuously variable transmission that uses the reverse input prevention clutch. [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 moves the movable sheave in the axial direction by converting the rotation transmitted from the electric motor via the rotation transmission path into axial movement of the movable sheave using the motion conversion mechanism.

[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. Specifically, the movable sheave and the fixed sheave receive a radially inward force from the transmission belt, which is wound around the V-groove formed by the movable sheave and the fixed sheave. This radially inward force causes an axial component of force acting on the slope of the V-groove of the movable sheave, moving it away from the fixed 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 against the axial component of the force received from the transmission belt is to use the torque of 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, and this axial force is used to cancel out the axial component of the force received from the transmission belt, thereby preventing axial movement of the movable sheave 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 by 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 while the axial position of the movable sheave is being maintained without movement.Furthermore, the electric motor must be large in size to ensure the torque sufficient 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] That is, the reverse input prevention clutch of Patent Document 1 includes an input shaft to which rotation is input, an output shaft rotatably supported coaxially with the input shaft, a fixed outer ring fixed so as not to rotate, and multiple pairs of rollers mounted between the cylindrical surface of the inner circumference of the fixed outer ring and the outer circumference of the output shaft. A plurality of planar cam surfaces, each formed by linearly cutting out a portion of the outer circumference of the output shaft, are formed at intervals in the circumferential direction on the outer circumference of the output shaft, and a pair of rollers is disposed between each cam surface and the cylindrical surface of the inner circumference of the fixed outer ring. Each pair of rollers is biased in a direction to engage between the cam surface and the cylindrical surface by a roller biasing spring compressed and mounted between the two rollers that make up that pair. Each pair of rollers is held by a roller cage connected to the input shaft so as to rotate integrally with the input shaft. A floating connecting portion is provided between the input shaft and the output shaft, connecting them with circumferential play.

[0012] In this reverse input prevention clutch, when rotation is input to the input shaft, the roller cage, which rotates integrally with the input shaft, presses the rear roller of each pair of rollers in the rotational direction, so that the rollers do not become trapped between the cam surface on the outer circumference of the output shaft and the cylindrical surface on the inner circumference of the fixed outer ring. When the input shaft rotates beyond the range of circumferential play of the floating coupling, the rotation of the input shaft is transmitted to the output shaft via the floating coupling, and the input and output shafts rotate integrally.

[0013] On the other hand, when rotation is input to the output shaft (i.e., when reverse input occurs), the cam surface on the outer periphery of the cam surface moves circumferentially relative to the cylindrical surface on the inner periphery of the fixed outer ring, so that the rear roller in the rotational direction of each pair of rollers becomes engaged between the cam surface on the outer periphery of the output shaft and the cylindrical surface on the inner periphery of the fixed outer ring, preventing the output shaft from rotating any further and locking it in place, thereby preventing transmission of rotation from the output shaft to the input shaft.

[0014] Thereafter, when rotation is input to the input shaft again, the roller retainer, 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.The rotation of the input shaft is then transmitted to the output shaft via the floating connecting portion, and the input shaft and output shaft rotate integrally.

[0015] 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 directly engaging between the output shaft and the fixed outer ring, and the action of unlocking the output shaft is also a sudden action caused by the rollers being released from their direct engagement.

[0016] Therefore, when this reverse input prevention clutch is incorporated into the above-mentioned actuator for a continuously variable transmission that moves the movable sheave axially, there is a problem that the movable sheave may not move smoothly when moving axially away from the fixed sheave.

[0017] In other words, when a reverse input prevention clutch is incorporated into an actuator for a continuously variable transmission, the axial component force acting on the movable sheave from the transmission belt is transmitted to the reverse input prevention clutch via the motion conversion mechanism, so that the output shaft of the reverse input prevention clutch is always subjected to reverse input torque.

[0018] On the other hand, when the movable sheave is moved axially away from the fixed sheave, rotation generated by the electric motor is input to the input shaft of the reverse input prevention clutch, and the direction of that rotation is the same as the direction of the reverse input torque acting on the output shaft of the reverse input prevention clutch.

[0019] Therefore, when the movable sheave is moved axially away from the fixed sheave, a phenomenon may occur in which the rotational speed of the output shaft of the reverse input prevention clutch exceeds the rotational speed of the input shaft, causing the output shaft to lock, and then the rotational speed of the input shaft exceeds the rotational speed of the output shaft, causing the output shaft to unlock alternately.

[0020] In the reverse input prevention clutch of Patent Document 1, the locking operation of the output shaft is a sudden operation caused by direct engagement of the rollers, and similarly, the unlocking operation of the output shaft is a sudden operation caused by the rollers being released from direct engagement. As a result, the axial movement of the movable sheave is an intermittent operation that alternates between acceleration and deceleration, which can cause the movable sheave to not move smoothly.

[0021] Furthermore, Patent Document 2 proposes a reverse input prevention clutch similar to that of Patent Document 1, in which a number of balls are incorporated at intervals in the circumferential direction on the outer periphery of the output shaft, and the balls are engaged axially between a fixed outer ring and the output shaft, thereby locking the output shaft. However, when this reverse input prevention clutch is incorporated into the rotation transmission path of an actuator for a continuously variable transmission, there is a problem, similar to that of Patent Document 1, in that the movable sheave may not move smoothly.

[0022] 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. [Means for solving the problem]

[0023] 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 rotatably supported coaxially with the input shaft; a fixed outer ring having an inner peripheral friction surface and fixed so as not to rotate; a divided outer ring frictionally engaging the inner peripheral friction surface; a first roller and a second roller incorporated between the inner periphery of the split outer ring and the outer periphery of the output shaft, a first cam surface that forms a wedge-shaped space between the split outer ring and the output shaft and that narrows gradually toward one side in the circumferential direction, and a second cam surface that forms a wedge-shaped space between the split outer ring and the output shaft and that narrows gradually toward the other side in the circumferential direction, the one-side roller is disposed between the one-side cam surface and the divided outer ring, and the other-side roller is disposed between the other-side cam surface and the divided outer ring, a roller biasing spring is provided to bias the one-side roller to one side in the circumferential direction and to bias the other-side roller to the other side in the circumferential direction; The input shaft is provided with an other-side roller pressing portion that moves integrally with the input shaft when the input shaft rotates in one circumferential direction to press the other-side roller in one circumferential direction, and a one-side roller pressing portion that moves integrally with the input shaft when the input shaft rotates in the other circumferential direction to press the one-side roller in the other circumferential direction, A reverse input prevention clutch in which a floating connecting portion is provided between the input shaft and the output shaft, connecting the two with circumferential play.

[0024] With this configuration, when rotation in one circumferential direction is input to the input shaft, the other-side roller pressing portion, which rotates integrally with the input shaft, pushes the other-side roller toward one circumferential direction, preventing the other-side roller from becoming caught between the other-side cam surface on the outer periphery of the output shaft and the divided outer ring. When the input shaft rotates toward one circumferential direction beyond the range of circumferential play of the floating coupling portion, the rotation of the input shaft is transmitted to the output shaft via the floating coupling portion, causing the output shaft to rotate toward one circumferential direction integrally with the input shaft. Similarly, when rotation in the other circumferential direction is input to the input shaft, the output shaft also rotates toward the other circumferential direction integrally with the input shaft.

[0025] On the other hand, when rotation in one circumferential direction is input to the output shaft, the other-side cam surface on the outer circumference of the output shaft moves to one circumferential direction, so that the other-side roller engages between the other-side cam surface on the outer circumference of the output shaft and the divided outer ring, and the engagement of the other-side roller presses the divided outer ring radially outward, causing the outer periphery of the divided outer ring to frictionally engage with the inner circumferential friction surface of the fixed outer ring, which prevents rotation of the output shaft to one circumferential direction and locks the output shaft, preventing transmission of rotation from the output shaft to the input shaft.

[0026] Thereafter, when rotation in one circumferential direction is input to the input shaft, the other-side roller pressing portion, which rotates integrally with the input shaft, presses the other-side roller in one circumferential direction, so that the other-side roller is no longer engaged between the other-side cam surface on the outer periphery of the output shaft and the divided outer ring, releasing the frictional engagement between the outer periphery of the divided outer ring and the inner circumferential friction surface of the fixed outer ring. This release of frictional engagement allows the output shaft to rotate in one circumferential direction, and the output shaft is unlocked. The rotation of the input shaft is then transmitted to the output shaft via the floating connecting portion, and the output shaft rotates in one circumferential direction together with the input shaft.

[0027] Similarly, when rotation in the other circumferential direction is input to the output shaft, the one-side roller meshes between the one-side cam surface on the outer periphery of the output shaft and the divided outer ring, and this meshing presses the divided outer ring radially outward, causing the outer periphery of the divided outer ring to frictionally engage with the inner circumferential friction surface of the fixed outer ring, and this frictional engagement prevents rotation of the output shaft in the other circumferential direction. Then, when rotation in the other circumferential direction is input to the input shaft, the one-side roller pressing portion presses the one-side roller out of meshing with the one-side cam surface on the outer periphery of the output shaft and the divided outer ring, releasing the frictional engagement between the outer periphery of the divided outer ring and the inner circumferential friction surface of the fixed outer ring, and the output shaft rotates in the other circumferential direction together with the input shaft.

[0028] Here, when rotation is input to the output shaft (i.e., when reverse input occurs), rather than directly engaging rollers between the output shaft and the fixed outer ring, one roller or the other roller is engaged between the output shaft and the divided outer ring, and the outer periphery of the divided outer ring is frictionally engaged with the inner circumferential friction surface of the fixed outer ring to prevent rotation of the output shaft, thereby gently locking the output shaft. Similarly, when unlocking the output shaft, the frictional engagement between the outer periphery of the divided outer ring and the inner circumferential friction surface of the fixed outer ring is released, allowing rotation of the output shaft. Therefore, the unlocking operation of the output shaft is gentler than when directly releasing rollers from engagement between the output shaft and the fixed outer ring. 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, less likely to be an intermittent operation that alternates between acceleration and deceleration.

[0029] [Configuration 2] a plurality of one-side cam surfaces are formed on the outer periphery of the output shaft at intervals in the circumferential direction, The other cam surface is also formed in plurality at intervals in the circumferential direction on the outer periphery of the output shaft, a plurality of the one-side rollers and a plurality of the other-side rollers are provided corresponding to the plurality of one-side cam surfaces and the plurality of other-side cam surfaces, 2. The reverse input prevention clutch according to claim 1, wherein the split outer rings are provided in plurality so as to be aligned in a circumferential direction over the entire circumference along the inner peripheral friction surface of the fixed outer ring.

[0030] When this configuration is adopted, when rotation is input to the output shaft, the outer peripheries of the multiple split outer rings lined up circumferentially around the entire circumference simultaneously frictionally engage with the inner friction surface of the fixed outer ring, resulting in a stable operation of preventing rotation of the output shaft.

[0031] [Configuration 3] The reverse input prevention clutch according to configuration 2, further comprising an elastic member that biases the plurality of split outer rings radially inward.

[0032] By adopting this configuration, the multiple split outer rings are biased radially inward, making it possible to prevent frictional resistance (drag torque) from occurring between the outer periphery of the split outer rings and the inner friction surface of the fixed outer ring when the output shaft is unlocked (i.e., when the rotation input to the input shaft is transmitted to the output shaft and the output shaft rotates integrally with the input shaft).

[0033] [Configuration 4] a spring accommodating groove is formed on the outer periphery of each of the plurality of split outer rings, the spring accommodating groove extending through the split outer rings from one end to the other end in the circumferential direction; 4. The reverse input prevention clutch according to configuration 3, wherein the elastic member is an annular garter spring that passes through the spring accommodating grooves of the plurality of divided outer rings and continues around the entire circumference.

[0034] By adopting this configuration, it is possible to reliably bias each of the multiple split outer rings radially inward with a simple configuration.

[0035] [Configuration 5] the one-side cam surface and the other-side cam surface are portions on one circumferential side and the other circumferential side of a circumferential center of a plane having a shape obtained by linearly cutting out a portion of the outer periphery of the output shaft, 5. The reverse input prevention clutch according to any one of configurations 2 to 4, wherein the roller biasing spring is a spring that is compressed and incorporated between the one-side roller and the other-side roller.

[0036] [Configuration 6] A reverse input prevention clutch according to any one of configurations 2 to 5, wherein the circumferential end faces of the plurality of split outer rings form inclined surfaces that are inclined with respect to the radial direction so as to extend obliquely when viewed from the axial direction.

[0037] By adopting this configuration, even when one side roller or the other side roller is at a circumferential position corresponding to the space between adjacent split outer rings in the circumferential direction, when rotation is input to the output shaft and the one side roller or the other side roller becomes wedged between the output shaft and the split outer ring, stable frictional engagement can be achieved between the outer periphery of the split outer ring and the inner friction surface of the fixed outer ring.

[0038] [Configuration 7] A reverse input prevention clutch according to any one of configurations 2 to 5, wherein the circumferential end faces of the plurality of split outer rings form inclined surfaces inclined with respect to the axial direction so as to extend obliquely when viewed from the radial direction.

[0039] By adopting this configuration, even when one side roller or the other side roller is at a circumferential position corresponding to the space between adjacent split outer rings in the circumferential direction, when rotation is input to the output shaft and the one side roller or the other side roller becomes wedged between the output shaft and the split outer ring, stable frictional engagement can be achieved between the outer periphery of the split outer ring and the inner friction surface of the fixed outer ring.

[0040] The present invention also provides an actuator for a continuously variable transmission using the reverse input prevention clutch having the above-described configuration, which has the following configuration. [Configuration 8] 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 7, 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]

[0041] The reverse input prevention clutch of this invention prevents rotation of the output shaft by engaging one or the other roller between the output shaft and the split outer ring, rather than directly engaging a roller between the output shaft and the fixed outer ring, and frictionally engaging the outer periphery of the split outer ring with the inner friction surface of the fixed outer ring, thereby locking the output shaft smoothly. Similarly, when the output shaft is unlocked, the frictional engagement between the outer periphery of the split outer ring and the inner friction surface of the fixed outer ring is released, allowing rotation of the output shaft. This allows for a smoother unlocking of the output shaft than when a roller is directly released from engagement between the output shaft and the fixed outer ring. 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 less likely to be an intermittent operation that alternates between acceleration and deceleration, and is therefore smoother. [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a partial cross-sectional view of a reverse input prevention clutch according to a first embodiment of the present invention. [Figure 2] Cross-sectional view along line II-II in Figure 1 [Figure 3] An exploded perspective view of the fixed outer ring, input shaft, split outer ring, and output shaft shown in Figure 1 [Figure 4] An enlarged view of a portion of Figure 2. [Figure 5] 5 is a diagram corresponding to FIG. 4 and illustrating a state in which the input shaft shown in FIG. 1 has rotated to one side in the circumferential direction. [Figure 6] FIG. 5 is a diagram showing a modified example of the split outer ring shown in FIG. 4. [Figure 7] FIG. 10 is a partial cross-sectional view of a reverse input prevention clutch according to a second embodiment of the present invention. [Figure 8] Cross-sectional view taken along line VIII-VIII in Figure 7 [Figure 9] FIG. 2 is a diagram showing an actuator for a continuously variable transmission using a reverse input prevention clutch 1 having a configuration corresponding to the reverse input prevention clutch shown in FIG. [Figure 10] Enlarged view of the reverse input prevention clutch in Figure 9 [Figure 11] Cross-sectional view taken along line XI-XI in Figure 10 DETAILED DESCRIPTION OF THE INVENTION

[0043] Figure 1 shows a reverse input prevention clutch 1 according to a first embodiment of the present invention. This reverse input prevention clutch 1 has an input shaft 2 to which rotation is input, an output shaft 3 rotatably supported coaxially with the input shaft 2, a fixed outer ring 4 that is fixed so as not to rotate, a plurality of partially annular divided outer rings 5 ​​incorporated between the inner periphery of the fixed outer ring 4 and the outer periphery of the output shaft 3, and one-side rollers 6a and the other-side rollers 6b (see Figure 2) incorporated between the inner periphery of the divided outer ring 5 and the outer periphery of the output shaft 3.

[0044] The axial direction is the direction parallel to the central axis (central axis of rotation) of the input shaft 2, the radial direction is the direction perpendicular to the central axis of the input shaft 2, and the circumferential direction is the direction along the circumference centered on the central axis of the input shaft 2.

[0045] An inner friction surface 7 is formed on the inner circumference of the fixed outer ring 4, facing radially toward the outer circumference of the divided outer ring 5. The inner friction surface 7 is an annular surface that is continuous in the circumferential direction over the entire circumference. In this example, the inner friction surface 7 is a cylindrical surface with a constant inner diameter along the axial direction. The center of this cylindrical surface is the center of the output shaft 3.

[0046] As shown in FIG. 2, an outer peripheral friction surface 8 is formed on the outer periphery of the split outer ring 5. The outer peripheral friction surface 8 is a surface that frictionally engages with the inner peripheral friction surface 7 of the fixed outer ring 4 when the split outer ring 5 is pressed radially outward by engagement with one roller 6a or the other roller 6b. The outer peripheral friction surface 8 is a surface that extends circumferentially over an angular range corresponding to a portion of the circumference, and in this case is a partial cylindrical surface obtained by circumferentially dividing a cylindrical surface. The radius of curvature of the outer peripheral friction surface 8 is set to be 97% or more and less than 100% of the radius of the inner peripheral friction surface 7 of the fixed outer ring 4. The inner circumference of the split outer ring 5 is formed with a partial cylindrical divided inner peripheral surface 9 having a center of curvature at the same position as the center of curvature of the outer peripheral friction surface 8.

[0047] A plurality of split outer rings 5 ​​are provided, lined up circumferentially along the entire circumference of the inner friction surface 7 of the fixed outer ring 4. All of the split outer rings 5 ​​have the same shape, and the circumferential length of each split outer ring 5 is equal to one another. The central angle of each split outer ring 5 is 90° in the figure, which is obtained by dividing 360° into multiple equal parts (four parts in the figure) in the circumferential direction.

[0048] As shown in Figure 4, the circumferential end face 10 of the split outer ring 5 faces the circumferential end face 10 of the circumferentially adjacent split outer ring 5. In other words, the end face 10 on the other circumferential side (left side in the figure) of the split outer ring 5 on one circumferential side (right side in the figure) of the circumferentially adjacent split outer rings 5 ​​faces the end face 10 on one circumferential side (right side in the figure) of the split outer ring 5 on the other circumferential side (left side in the figure). The circumferential end face 10 of the split outer ring 5 is a flat surface perpendicular to the circumferential direction.

[0049] One-side cam surface 11a and other-side cam surface 11b are formed side by side in the circumferential direction on the outer periphery of output shaft 3. One-side cam surface 11a faces divided inner circumferential surface 9 of divided outer ring 5 in the radial direction, and forms a wedge-shaped space between divided inner circumferential surface 9 that gradually narrows toward one circumferential side (the right side in the figure). The other-side cam surface 11b also faces divided inner circumferential surface 9 of divided outer ring 5 in the radial direction, and forms a wedge-shaped space between divided inner circumferential surface 9 that gradually narrows toward the other circumferential side (the left side in the figure). Here, one-side cam surface 11a and other-side cam surface 11b are portions on one circumferential side and the other circumferential side of the circumferential center of a plane that has a shape obtained by cutting a portion of the outer periphery of output shaft 3 linearly as viewed from the axial direction.

[0050] 2, a plurality of one-side cam surfaces 11a are formed at intervals in the circumferential direction on the outer periphery of output shaft 3, and a plurality of other-side cam surfaces 11b are also formed at intervals in the circumferential direction on the outer periphery of output shaft 3. The number of one-side cam surfaces 11a and the number of other-side cam surfaces 11b are an integer multiple (twice in the figure) of the number of divided outer rings 5 ​​(four in the figure) (eight in the figure).

[0051] As shown in Figure 4, one-side roller 6a is disposed between one-side cam surface 11a and divided inner circumferential surface 9 of split outer ring 5, and the other-side roller 6b is disposed between the other-side cam surface 11b and divided inner circumferential surface 9 of split outer ring 5. One-side roller 6a and other-side roller 6b are both rollers with cylindrical surfaces. The diameters of one-side roller 6a and other-side roller 6b are equal.

[0052] A roller biasing spring 12 is provided between the one roller 6a and the other roller 6b. The roller biasing spring 12 is compressed and incorporated between the one roller 6a and the other roller 6b, and its elastic restoring force biases the one roller 6a to one circumferential side (to the right in the figure) and biases the other roller 6b to the other circumferential side (to the left in the figure). The biasing force of this roller biasing spring 12 brings the one roller 6a into contact with the one cam surface 11a and the divided inner circumferential surface 9 of the split outer ring 5 simultaneously, and the other roller 6b into contact with the other cam surface 11b and the divided inner circumferential surface 9 of the split outer ring 5 simultaneously.

[0053] As shown in Figure 2, multiple one-side rollers 6a (eight in the figure) are provided corresponding to the number of one-side cam surfaces 11a, and multiple other-side rollers 6b (eight in the figure) are provided corresponding to the number of other-side cam surfaces 11b.

[0054] As shown in Figures 1 and 2, the input shaft 2 is provided with a pillar portion 13 that extends in the axial direction between the outer periphery of the output shaft 3 and the inner periphery of the split outer ring 5. As shown in Figures 1 and 3, the pillar portion 13 is provided and connected to the input shaft 2 so as to move in the circumferential direction integrally with the input shaft 2 when the input shaft 2 rotates. In Figures 1 and 3, the pillar portion 13 is formed integrally with the input shaft 2, but the pillar portion 13 may also be formed separately from the input shaft 2 and fixed to the input shaft 2.

[0055] 4, each pillar portion 13 is provided at a circumferential position facing one circumferential side (right side in the figure) of the one-side roller 6a and corresponding to the other circumferential side (left side in the figure) of the other-side roller 6b. Here, the end on the other circumferential side (left end in the figure) of the pillar portion 13 facing the one circumferential side (right side in the figure) of the one-side roller 6a constitutes the one-side roller pressing portion 13a, and the end on the one circumferential side (right end in the figure) of the pillar portion 13 facing the other circumferential side (left side in the figure) of the other-side roller 6b constitutes the other-side roller pressing portion 13b. One-side roller pressing portion 13a is a portion that moves integrally with input shaft 2 to press one-side roller 6a to the other circumferential side (left side in the figure) when input shaft 2 rotates to the other circumferential side (left side in the figure), and the other-side roller pressing portion 13b is a portion that moves integrally with input shaft 2 to press the other-side roller 6b to one circumferential side (right side in the figure) when input shaft 2 rotates to the one circumferential side (right side in the figure). One-side roller pressing portion 13a faces one circumferential side (right side in the figure) of one-side roller 6a via a small gap, and the other-side roller pressing portion 13b also faces the other circumferential side (left side in the figure) of other-side roller 6b via a small gap.

[0056] 1 and 2, a floating coupling portion 14 is provided between the input shaft 2 and the output shaft 3, connecting them with a circumferential play. In this example, the floating coupling portion 14 is a convex portion 15 provided on the input shaft 2 and a concave portion 16 provided on the output shaft 3. As shown in FIGS. 4 and 5, the convex portion 15 engages with the concave portion 16 with a circumferential gap.

[0057] The floating connecting portion 14 connects the input shaft 2 and the output shaft 3 so that, when the input shaft 2 shown in FIG. 1 rotates relative to the output shaft 3, the input shaft 2 is allowed to rotate relative to the output shaft 3 as long as the rotation angle of the input shaft 2 relative to the output shaft 3 is within the range of circumferential play (the circumferential gap between the convex portion 15 and the concave portion 16 shown in FIG. 4), and no rotation is transmitted from the input shaft 2 to the output shaft 3; on the other hand, when the rotation angle of the input shaft 2 relative to the output shaft 3 exceeds the range of the circumferential play (the circumferential gap between the convex portion 15 and the concave portion 16 shown in FIG. 4), the rotation of the input shaft 2 is transmitted to the output shaft 3, and the output shaft 3 rotates integrally with the input shaft 2.

[0058] The magnitude of the circumferential play of the floating connecting portion 14 (the magnitude of the circumferential gap between the convex portion 15 and the concave portion 16 shown in FIG. 4) is set so that when the input shaft 2 shown in FIG. 4 rotates to one circumferential side (the right side in the figure) and the other-side roller pressing portion 13b comes into contact with the other-side roller 6b, the convex portion 15 does not yet come into contact with the inner circumferential end surface of the concave portion 16, and circumferential play remains. Similarly, when the input shaft 2 rotates to the other circumferential side (the left side in the figure) and the one-side roller pressing portion 13a comes into contact with the one-side roller 6a, the convex portion 15 does not yet come into contact with the inner circumferential end surface of the concave portion 16, and circumferential play remains.

[0059] As shown in FIG. 5 , in this reverse input prevention clutch 1, when rotation in one circumferential direction (the right side in the figure) is input to the input shaft 2, the other-side roller pressing portion 13b, which rotates integrally with the input shaft 2, pushes the other-side roller 6b toward one circumferential direction (the right side in the figure), so that the other-side roller 6b does not become caught between the other-side cam surface 11b on the outer periphery of the output shaft 3 and the divided outer ring 5. When the input shaft 2 rotates toward one circumferential direction (the right side in the figure) beyond the range of circumferential play of the floating coupling portion 14, the rotation of the input shaft 2 is transmitted to the output shaft 3 via the floating coupling portion 14, and the output shaft 3 rotates toward one circumferential direction (the right side in the figure) integrally with the input shaft 2. Similarly, when rotation in the other circumferential direction (the left side in the figure) is input to the input shaft 2, the output shaft 3 rotates toward the other circumferential direction (the left side in the figure) integrally with the input shaft 2.

[0060] 4, when rotation in one circumferential direction (the right side in the figure) is input to the output shaft 3, the other-side cam surface 11b on the outer circumference of the output shaft 3 moves to one circumferential direction (the right side in the figure), so that the other-side roller 6b gets engaged between the other-side cam surface 11b on the outer circumference of the output shaft 3 and the divided outer ring 5. The engagement of the other-side roller 6b presses the divided outer ring 5 radially outward, and the partially annular outer peripheral friction surface 8 of the divided outer ring 5 frictionally engages with the annular inner peripheral friction surface 7 of the fixed outer ring 4. This frictional engagement prevents the output shaft 3 from rotating to one circumferential direction (the right side in the figure), and the output shaft 3 becomes locked. Therefore, transmission of rotation from the output shaft 3 to the input shaft 2 is prevented.

[0061] Thereafter, when rotation in one circumferential direction (the right side in the figure) is input to the input shaft 2, the other-side roller pressing portion 13b, which rotates integrally with the input shaft 2, presses the other-side roller 6b to one circumferential direction (the right side in the figure), so that, as shown in Figure 5, the other-side roller 6b is disengaged from the other-side cam surface 11b on the outer periphery of the output shaft 3 and the split outer ring 5, releasing the frictional engagement between the outer peripheral friction surface 8 of the split outer ring 5 and the inner peripheral friction surface 7 of the fixed outer ring 4. This release of frictional engagement allows the output shaft 3 to rotate to one circumferential direction (the right side in the figure), and the output shaft 3 is unlocked. Thereafter, the rotation of the input shaft 2 is transmitted to the output shaft 3 via the floating connecting portion 14, and the output shaft 3 rotates integrally with the input shaft 2 to one circumferential direction (the right side in the figure).

[0062] 4, when rotation in the other circumferential direction (left side in the figure) is input to the output shaft 3, the one-side roller 6a is engaged between the one-side cam surface 11a on the outer circumference of the output shaft 3 and the divided outer ring 5, and this engagement presses the divided outer ring 5 radially outward, causing the partially annular outer peripheral friction surface 8 of the divided outer ring 5 to frictionally engage with the annular inner peripheral friction surface 7 of the fixed outer ring 4, and this frictional engagement prevents rotation of the output shaft 3 in the other circumferential direction (left side in the figure). Then, when rotation in the other circumferential direction (left side in the figure) is input to the input shaft 2, the one-side roller 6a is disengaged from the engagement between the one-side cam surface 11a on the outer circumference of the output shaft 3 and the divided outer ring 5 due to the pressure from the one-side roller pressing portion 13a, thereby releasing the frictional engagement between the outer peripheral friction surface 8 of the divided outer ring 5 and the inner peripheral friction surface 7 of the fixed outer ring 4, and the output shaft 3 rotates integrally with the input shaft 2 in the other circumferential direction (left side in the figure).

[0063] Here, when rotation is input to the output shaft 3 shown in Fig. 4 (i.e., when a reverse input occurs), rather than directly engaging rollers between the output shaft 3 and the fixed outer ring 4, one side roller 6a or the other side roller 6b is engaged between the output shaft 3 and the split outer ring 5, and the partially annular outer peripheral friction surface 8 of the split outer ring 5 is frictionally engaged with the annular inner peripheral friction surface 7 of the fixed outer ring 4, thereby preventing rotation of the output shaft 3, thereby gradual locking of the output shaft 3. Similarly, when unlocking the output shaft 3, the frictional engagement between the outer peripheral friction surface 8 of the split outer ring 5 and the inner peripheral friction surface 7 of the fixed outer ring 4 is released, allowing rotation of the output shaft 3. Therefore, the unlocking operation of the output shaft 3 is gradual compared to when rollers are directly released from engagement between the output shaft 3 and the fixed outer ring 4.

[0064] 2, this reverse input prevention clutch 1 is provided with a plurality of one-side cam surfaces 11a, other-side cam surfaces 11b, one-side rollers 6a, and other-side rollers 6b spaced apart in the circumferential direction, and a plurality of split outer rings 5 ​​are also provided so as to be lined up in the circumferential direction all around along the inner peripheral friction surface 7 of the fixed outer ring 4, so that when rotation is input to the output shaft 3, the outer peripheral friction surfaces 8 of the plurality of split outer rings 5 ​​lined up all around simultaneously frictionally engage with the inner peripheral friction surface 7 of the fixed outer ring 4. This ensures stable operation in preventing rotation of the output shaft 3.

[0065] In the above embodiment, as shown in Fig. 4, the circumferential end faces 10 of the split outer rings 5 ​​are flat surfaces perpendicular to the circumferential direction, but as shown in Fig. 6, the circumferential end faces 10 of the split outer rings 5 ​​may be sloped with respect to the radial direction so as to extend obliquely when viewed from the axial direction. In this way, even when one roller 6a or the other roller 6b is located in a circumferential position corresponding to the space between circumferentially adjacent split outer rings 5, when rotation is input to the output shaft 3 and one roller 6a or the other roller 6b is engaged between the output shaft 3 and the split outer rings 5, stable frictional engagement can be achieved between the outer peripheral friction surface 8 of the split outer ring 5 and the inner peripheral friction surface 7 of the fixed outer ring 4.

[0066] Similarly, the circumferential end faces 10 of the split outer rings 5 ​​may be sloped with respect to the axial direction so as to extend obliquely when viewed radially. Even in this case, even when one roller 6a or the other roller 6b is in a circumferential position corresponding to the space between circumferentially adjacent split outer rings 5, when rotation is input to the output shaft 3 and one roller 6a or the other roller 6b is engaged between the output shaft 3 and the split outer ring 5, stable frictional engagement can be achieved between the outer peripheral friction surface 8 of the split outer ring 5 and the inner peripheral friction surface 7 of the fixed outer ring 4.

[0067] 7 and 8 show a second embodiment of the present invention. The second embodiment differs from the first embodiment only in that it is provided with elastic members (garter springs 17) that urge each split outer ring 5 radially inward, but the other configurations are the same. Therefore, parts corresponding to those in the first embodiment are given the same reference numerals and descriptions thereof will be omitted.

[0068] A spring accommodating groove 18 is formed on the outer periphery of each split outer ring 5, extending from one circumferential end to the other end of the split outer ring 5. An annular garter spring 17 is accommodated in the spring accommodating groove 18 of each split outer ring 5 so as to pass through the spring accommodating groove 18 and continue around the entire circumference.

[0069] Garter spring 17 is a spring member formed into a ring by connecting both ends of a coil spring whose coil length is sufficiently long compared to its outer diameter (specifically, a coil spring whose coil length is at least 20 times the outer diameter). The depth of spring accommodating groove 18 is greater than the outer diameter of garter spring 17, which prevents garter spring 17 from protruding radially outward from outer peripheral friction surface 8 of split outer ring 5.

[0070] Garter springs 17 are housed in spring accommodating grooves 18 in an elastically stretched state, and their elastic restoring force presses against the groove bottoms of spring accommodating grooves 18, urging each split outer ring 5 radially inward. The urging force of these garter springs 17 brings circumferential end faces 10 of circumferentially adjacent split outer rings 5 ​​into contact with each other, while keeping outer peripheral friction surfaces 8 of the split outer rings 5 ​​out of contact with inner peripheral friction surface 7 of the fixed outer ring 4.

[0071] The reverse input prevention clutch 1 of this embodiment is provided with garter springs 17 that urge each split outer ring 5 radially inward, so that when the output shaft 3 is unlocked (i.e., when the rotation input to the input shaft 2 is transmitted to the output shaft 3 and the output shaft 3 rotates integrally with the input shaft 2), it is possible to prevent frictional resistance (drag torque) from occurring between the outer peripheral friction surface 8 of the split outer ring 5 and the inner peripheral friction surface 7 of the fixed outer ring 4.

[0072] 9 shows an actuator for a continuously variable transmission using a reverse input prevention clutch 1 having a configuration corresponding to the first embodiment. This actuator for a continuously variable transmission is an actuator that moves a movable sheave 23 of a belt-type continuously variable transmission in the axial direction.

[0073] The belt-type continuously variable transmission includes a drive pulley 20, a driven pulley (not shown), and a transmission belt 21 wound between the drive pulley 20 and the driven pulley. The drive pulley 20 is configured with a fixed sheave 22 and a movable sheave 23 that face each other in the axial direction. A V-groove 24, around which the transmission belt 21 is wound, is formed between the fixed sheave 22 and the movable sheave 23. That is, one of the slopes of the V-groove 24 is formed in the fixed sheave 22, and the other slope of the V-groove 24 is formed in the movable sheave 23. By moving the movable sheave 23 in the axial direction, the width of the V-groove 24 can be changed. A continuously variable transmission actuator that moves the movable sheave 23 in the axial direction is attached to the movable sheave 23. The driven pulley (not shown) is configured similarly to the drive pulley 20.

[0074] In this belt-type continuously variable transmission, when the movable sheave 23 is moved axially by the continuously variable transmission actuator, the width of the V-groove 24 between the fixed sheave 22 and the movable sheave 23 changes, making it possible to continuously change the winding diameter of the power transmission belt 21 around the drive pulley 20. Similarly, the driven pulley (not shown) can also continuously change the winding diameter of the power transmission belt 21. This continuously changes the ratio between the winding diameter of the drive pulley 20 and the winding diameter of the driven pulley (not shown), thereby continuously adjusting the speed ratio.

[0075] The actuator for a continuously variable transmission has an electric motor 25 that outputs rotation, a rotation transmission path 26 that transmits the rotation output from the electric motor 25, and a motion conversion mechanism 27 that converts the rotation transmitted from the electric motor 25 via the rotation transmission path 26 into axial movement of the movable sheave 23. A reverse input prevention clutch 1 is incorporated into the rotation transmission path 26. The reverse input prevention clutch 1 is a mechanism that allows the transmission of rotation from the electric motor 25 side to the movable sheave 23 side and prevents the transmission of rotation from the movable sheave 23 side to the electric motor 25 side.

[0076] The electric motor 25 has a motor output shaft 28 and a motor body 29 that rotates and drives the motor output shaft 28. The rotation transmission path 26 has, in order from the electric motor 25 side toward the motion conversion mechanism 27 side, a first gear 31, a second gear 32, the reverse input prevention clutch 1, a third gear 33, and a fourth gear 34. The first gear 31 is fixed to the motor output shaft 28 and meshes with a second gear 32 that is fixed to the input shaft 2 of the reverse input prevention clutch 1. As a result, the rotation of the motor is input to the reverse input prevention clutch 1 via the first gear 31 and the second gear 32 in this order. The number of teeth of the second gear 32 is set to be greater than the number of teeth of the first gear 31, so that the rotation output from the electric motor 25 is transmitted to the input shaft 2 of the reverse input prevention clutch 1 at a reduced speed.

[0077] The input shaft 2 of the reverse input prevention clutch 1 is rotatably supported by an input side bearing 36 incorporated in a housing 35. The output shaft 3 of the reverse input prevention clutch 1 is also rotatably supported by an output side bearing 37 incorporated in the housing 35.

[0078] As shown in Figure 10, the fixed outer ring 4 of the reverse input prevention clutch 1 is fitted into a fitting hole 38 of a housing 35 and fixed to the housing 35 by a pin 39 provided on the housing 35. When the fixed outer ring 4 formed separately from the housing 35 is fixed to the housing 35 as shown in Figure 10, it becomes easy to process the inner friction surface 7 of the fixed outer ring 4, but it is also possible to form the fixed outer ring 4 integrally with the housing 35 (that is, to form the inner friction surface 7 directly on the housing 35).

[0079] As shown in FIG. 9 , the third gear 33 is fixed to the output shaft 3 of the reverse input prevention clutch 1, and the third gear 33 meshes with a fourth gear 34 provided on a nut member 40 of the motion conversion mechanism 27. As a result, the rotation output from the reverse input prevention clutch 1 is input to the motion conversion mechanism 27 via the third gear 33 and then the fourth gear 34. The number of teeth of the fourth gear 34 is set to be greater than the number of teeth of the third gear 33, so that the rotation output from the output shaft 3 of the reverse input prevention clutch 1 is decelerated and transmitted to the nut member 40 of the motion conversion mechanism 27. The third gear 33 has an axial width dimension greater than the axial width dimension of the fourth gear 34 so that the third gear 33 maintains meshing with the fourth gear 34 even when the fourth gear 34 moves axially relative to the third gear 33.

[0080] In the figure, the motion converting mechanism 27 is a so-called ball screw mechanism, and has a screw shaft 41, a nut member 40, and a plurality of balls 42. The nut member 40 is threadably engaged with the screw shaft 41 via the balls 42. When the nut member 40 rotates relative to the screw shaft 41, the nut member 40 moves in the axial direction relative to the screw shaft 41. A sliding screw mechanism may be used as the motion converting mechanism 27.

[0081] The nut member 40 is provided with a fourth gear 34, and when the fourth gear 34 rotates, the nut member 40 rotates integrally with the fourth gear 34. The screw shaft 41 is fixed to the housing 35 so as not to move or rotate in the axial direction relative to the housing 35. A rolling bearing 43 is incorporated between the nut member 40 and the movable sheave 23. The rolling bearing 43 connects the nut member 40 and the movable sheave 23 so that the rotation of the movable sheave 23 is not transmitted to the nut member 40. In addition, the nut member 40 is connected to the movable sheave 23 via the rolling bearing 43 so that when the nut member 40 moves in the axial direction, the movable sheave 23 moves axially integrally with the nut member 40.

[0082] In this motion converting mechanism 27, when the fourth gear 34 rotates, the nut member 40 rotates integrally with the fourth gear 34. Here, the screw shaft 41 is prevented from rotating relative to the housing 35, and its axial movement is restricted. Therefore, when the nut member 40 rotates, the nut member 40 moves axially, and the movable sheave 23 also moves axially integrally with the nut member 40.

[0083] The fixed sheave 22 has a sheave body 44 on which the slope of the V-groove 24 is formed, and a sheave shaft 45 extending in the axial direction from the sheave body 44. The sheave shaft 45 is rotatably supported by a rolling bearing 46 incorporated in the housing 35.

[0084] The movable sheave 23 is disposed opposite the sheave body 44 of the fixed sheave 22. The movable sheave 23 is formed in an annular shape, and the outer periphery of the sheave shaft 45 is fitted onto the inner periphery of the movable sheave 23. The fitting portion between the movable sheave 23 and the sheave shaft 45 is provided with a rotation preventing portion 47 (for example, a spline protrusion and a spline groove) that prevents the movable sheave 23 from rotating on the sheave shaft 45 while allowing the movable sheave 23 to move axially relative to the sheave shaft 45.

[0085] In the above-described belt-type continuously variable transmission, the axial position of the movable sheave 23 needs to be maintained against the axial component of the force received from the transmission belt 21. That is, the movable sheave 23 and the fixed sheave 22 receive a radially inward force from the transmission belt 21 wound around the V-groove 24, and this radially inward force causes an axial component of force in a direction away from the fixed sheave 22 (toward the left in the figure) to act on the slope of the V-groove 24 of the movable sheave 23. Therefore, unless the axial position of the movable sheave 23 is maintained by some method, the movable sheave 23 will move axially, changing the width of the V-groove 24 between the movable sheave 23 and the fixed sheave 22.

[0086] Therefore, a method using the torque of the electric motor 25 can be considered as a method for maintaining the axial position of the movable sheave 23 against the axial component of the force received from the transmission belt 21. That is, a method is considered in which torque is generated by the electric motor 25, and the torque is transmitted to the movable sheave 23 as an axial force via the rotation transmission path 26 and the motion conversion mechanism 27, and the axial force is used to cancel out the axial component of the force received from the transmission belt 21, thereby preventing the movable sheave 23 from moving in the axial direction and maintaining the width of the V-groove 24.

[0087] However, if the axial position of the movable sheave 23 is maintained by the torque of the electric motor 25, it is necessary to supply power to the electric motor 25 not only when the axial position of the movable sheave 23 is moved in order to change the winding diameter of the power transmission belt 21, but also at all times while the axial position of the movable sheave 23 is maintained without movement. Also, the electric motor 25 needs to be made larger in size in order to ensure a torque sufficient to prevent the axial movement of the movable sheave 23.

[0088] Therefore, in this embodiment, in order to maintain the axial position of the movable sheave 23, a reverse input prevention clutch 1 is incorporated into the rotation transmission path 26 to prevent transmission of rotation from the movable sheave 23 side to the electric motor 25 side. In other words, even if an axial component force acts from the transmission belt 21 on the slope of the V-groove 24 of the movable sheave 23 and this axial component force is converted into a rotational force (torque) by the motion conversion mechanism 27 and input to the rotation transmission path 26, the reverse input prevention clutch 1 prevents rotation due to the rotational force, thereby preventing axial movement of the movable sheave 23.

[0089] Here, in a conventional reverse input prevention clutch (which does not have a split outer ring 5 and locks the output shaft 3 by engaging a roller between the output shaft 3 and the fixed outer ring 4), the locking action of the output shaft 3 is a sudden action caused by the roller directly engaging between the output shaft 3 and the fixed outer ring 4, and the action of unlocking the output shaft 3 is also a sudden action caused by the roller no longer being directly engaged.

[0090] Therefore, if it is assumed that this conventional reverse input prevention clutch is incorporated into the rotation transmission path 26 at the position of the reverse input prevention clutch 1 shown in Figure 9, there is a problem in that the movable sheave 23 may not move smoothly when it is moved axially away from the fixed sheave 22.

[0091] That is, as shown in FIG. 9, when the reverse input prevention clutch 1 is incorporated into the rotation transmission path 26, the axial component force acting on the movable sheave 23 from the transmission belt 21 is transmitted to the reverse input prevention clutch 1 via the motion conversion mechanism 27, so that the output shaft 3 of the reverse input prevention clutch 1 is always subjected to reverse input torque.

[0092] On the other hand, when the movable sheave 23 is moved axially away from the fixed sheave 22, rotation generated by the electric motor 25 is input to the input shaft 2 of the reverse input prevention clutch 1, and the direction of that rotation is the same as the direction of the reverse input torque acting on the output shaft 3 of the reverse input prevention clutch 1.

[0093] Therefore, when the movable sheave 23 is moved axially away from the fixed sheave 22, a phenomenon may occur in which the rotational speed of the output shaft 3 of the reverse input prevention clutch 1 exceeds the rotational speed of the input shaft 2, causing the output shaft 3 to lock, and then the rotational speed of the input shaft 2 exceeds the rotational speed of the output shaft 3, causing the output shaft 3 to unlock alternately.

[0094] In a conventional reverse input prevention clutch, the locking operation of the output shaft 3 is a sudden operation caused by direct engagement of the rollers, and similarly, the unlocking operation of the output shaft 3 is a sudden operation caused by the direct disengagement of the rollers. Therefore, the axial movement of the movable sheave 23 is an intermittent operation that alternates between acceleration and deceleration, which can cause the movable sheave 23 to not move smoothly.

[0095] To address this problem, this embodiment uses a reverse input prevention clutch 1 configured to prevent rotation of the output shaft 3 by engaging one roller 6a or the other roller 6b between the output shaft 3 and the split outer ring 5 and frictionally engaging the partially annular outer friction surface 8 of the split outer ring 5 with the annular inner friction surface 7 of the fixed outer ring 4, as shown in Figures 10 and 11. This ensures a gradual locking operation of the output shaft 3. Similarly, when unlocking the output shaft 3, the frictional engagement between the outer friction surface 8 of the split outer ring 5 and the inner friction surface 7 of the fixed outer ring 4 is released, allowing rotation of the output shaft 3. This ensures a gradual unlocking operation of the output shaft 3. When the movable sheave 23 shown in Figure 9 is moved axially away from the fixed sheave 22, the axial movement of the movable sheave 23 is smooth and does not undergo intermittent motion in which acceleration and deceleration alternately repeat.

[0096] Figures 9 to 11 have been explained using as an example an actuator for a continuously variable transmission incorporating a reverse input prevention clutch 1 having a configuration corresponding to the first embodiment, but it is also possible to incorporate a reverse input prevention clutch 1 having a configuration corresponding to the second embodiment (i.e., a reverse input prevention clutch 1 provided with garter springs 17 that urge each split outer ring 5 radially inward, as shown in Figures 7 and 8) into an actuator for a continuously variable transmission.

[0097] 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]

[0098] 1. Reverse input prevention clutch 2 input shafts 3 output shaft 4 Fixed outer ring 5-split outer ring 6a One side roller 6b Other side roller 7 Inner friction surface 10 Circumferential end face 11a One side cam surface 11b Other side cam surface 12 Roller bias spring 13a One-side roller pressing portion 13b Other side roller pressing portion 14 Floating connection 17 Garter Springs 18 Spring accommodation groove 22 Fixed sheave 23 Movable sheave 25 Electric Motor 26 Rotation transmission path 27 Motion conversion mechanism

Claims

1. an input shaft (2) to which rotation is input; an output shaft (3) rotatably supported coaxially with the input shaft (2); a fixed outer ring (4) having an inner peripheral friction surface (7) and fixed so as not to rotate; a divided outer ring (5) that frictionally engages with the inner peripheral friction surface (7); a first roller (6a) and a second roller (6b) incorporated between the inner periphery of the split outer ring (5) and the outer periphery of the output shaft (3), On the outer periphery of the output shaft (3), a one-side cam surface (11a) is formed which forms a wedge-shaped space between the split outer ring (5) and the one-side cam surface (11b) which forms a wedge-shaped space between the split outer ring (5) and the one-side cam surface (11b) which forms a wedge-shaped space between the split outer ring (5) and the other-side cam surface (11b) which forms a wedge-shaped space between the split outer ring (5) and the other-side cam surface (11b) which forms a wedge-shaped space between the split outer ring (5) and the one ... one-side cam surface (11b) which forms a wedge-shaped space the one-side roller (6a) is disposed between the one-side cam surface (11a) and the divided outer ring (5), and the other-side roller (6b) is disposed between the other-side cam surface (11b) and the divided outer ring (5); a roller biasing spring (12) is provided to bias the one-side roller (6 a) toward one side in the circumferential direction and to bias the other-side roller (6 b) toward the other side in the circumferential direction; The input shaft (2) is provided with an other-side roller pressing portion (13b) that moves integrally with the input shaft (2) when the input shaft (2) rotates in one circumferential direction to press the other-side roller (6b) in one circumferential direction, and a one-side roller pressing portion (13a) that moves integrally with the input shaft (2) when the input shaft (2) rotates in the other circumferential direction to press the one-side roller (6a) in the other circumferential direction, The reverse input prevention clutch is provided with a floating connecting portion (14) between the input shaft (2) and the output shaft (3) that connects them with circumferential play.

2. The one-side cam surface (11a) is formed in plurality at intervals in the circumferential direction on the outer periphery of the output shaft (3), The other cam surface (11b) is also formed in plurality at intervals in the circumferential direction on the outer periphery of the output shaft (3), a plurality of the one-side rollers (6 a) and the other-side rollers (6 b) are provided corresponding to the plurality of one-side cam surfaces (11 a) and the plurality of other-side cam surfaces (11 b); 2. The reverse input prevention clutch according to claim 1, wherein a plurality of the split outer rings (5) are provided so as to be aligned in a circumferential direction along the entire circumference of the inner peripheral friction surface (7) of the fixed outer ring (4).

3. 3. A reverse input prevention clutch according to claim 2, further comprising an elastic member for biasing the plurality of split outer rings (5) radially inward.

4. A spring accommodating groove (18) is formed on the outer periphery of each of the plurality of split outer rings (5), the groove extending from one end to the other end in the circumferential direction of the split outer ring (5); 4. A reverse input preventing clutch according to claim 3, wherein the elastic member is an annular garter spring (17) that passes through the spring accommodating grooves (18) of the plurality of split outer rings (5) and continues around the entire circumference.

5. the one-side cam surface (11a) and the other-side cam surface (11b) are a portion on one circumferential side and a portion on the other circumferential side of a circumferential center of a plane having a shape obtained by linearly cutting out a part of the outer periphery of the output shaft (3), 5. A reverse input preventing clutch according to claim 2, wherein the roller biasing spring (12) is a spring that is compressed and incorporated between the one-side roller (6a) and the other-side roller (6b).

6. 5. A reverse input prevention clutch according to claim 2, wherein the circumferential end faces (10) of the plurality of split outer rings (5) form slopes that are inclined with respect to the radial direction so as to extend obliquely when viewed from the axial direction.

7. 5. A reverse input prevention clutch according to claim 2, wherein the circumferential end faces (10) of the plurality of split outer rings (5) form inclined surfaces that are inclined with respect to the axial direction so as to extend obliquely when viewed radially.

8. an electric motor (25) that outputs rotation; a rotation transmission path (26) for transmitting rotation output from the electric motor (25); a motion conversion mechanism (27) that converts the rotation transmitted from the electric motor (25) via the rotation transmission path (26) into axial movement of a movable sheave (23) that is disposed opposite to the fixed sheave (22) of the belt-type continuously variable transmission; and a reverse input prevention clutch (1) according to any one of claims 1 to 4, which is incorporated into the rotation transmission path (26) so as to allow transmission of rotation from the electric motor (25) side to the movable sheave (23) side and prevent transmission of rotation from the movable sheave (23) side to the electric motor (25).

Images