Reverse input prevention clutch

Abstract

The output shaft locking mechanism provides a stable reverse input prevention clutch. [Solution] A reverse input prevention clutch comprising an annular fixed outer ring 3 surrounding the outer circumference of an output shaft 2, a plurality of segmented outer rings 4 arranged adjacently in the circumferential direction along the inner circumference of the fixed outer ring 3, and one-sided rollers 5a and other-sided rollers 5b incorporated between the inner circumferences of the plurality of segmented outer rings 4 and the outer circumference of the output shaft 2, wherein the circumferential end faces 14 of each segmented outer ring 4 are inclined with respect to the axial direction so that the boundaries between adjacent segmented outer rings 4 extend diagonally with respect to the axial direction.

Description

[[Technical Field]]

[0001] The present invention relates to a reverse input prevention clutch. [[Background Art]]

[0002] A belt-type continuously variable transmission is known as a transmission for automobiles (e.g., Patent Document 1). The belt-type continuously variable transmission of Patent Document 1 includes a drive-side pulley, a driven-side pulley, and a transmission belt wound around between the drive-side pulley and the driven-side pulley. The drive-side pulley includes a fixed sheave having an axially fixed position, and a movable sheave that is axially movable by a sheave actuator, and a V-groove around which the transmission belt is wound is formed between the fixed sheave and the movable sheave.

[0003] This belt-type continuously variable transmission can change the width of the V-groove formed between the movable sheave and the fixed sheave by axially moving the movable sheave with the sheave actuator. When the width of the V-groove changes, the winding diameter of the transmission belt relative to the drive-side pulley changes, so that the gear ratio of rotation transmitted from the drive-side pulley to the driven-side pulley via the transmission belt changes.

[0004] Meanwhile, in the belt-type continuously variable transmission as described above, it is necessary to hold the axial position of the movable sheave against the axial component force of the force received from the transmission belt. That is, the movable sheave and the fixed sheave receive a radially inward force from the transmission belt wound around the V-groove, and the radially inward force causes an axial component force acting on a side away from the fixed sheave to act on the slope of the V-groove of the movable sheave. Therefore, unless the axial position of the movable sheave is held against the axial component force of the force received from the transmission belt, the movable sheave axially moves to the side away from the fixed sheave, and the width of the V-groove between the movable sheave and the fixed sheave widens.

[0005] Therefore, in Patent Document 1, in order to hold the axial position of the movable sheave against the axial component force of the force received from the transmission belt, a reverse input prevention clutch is incorporated in the sheave actuator.

[0006] In other words, a sheave actuator that moves a movable sheave in the axial direction comprises an electric motor and a motion conversion mechanism that converts the rotation of the electric motor into axial movement of the movable sheave. In Patent Document 1, a reverse input prevention clutch is incorporated into the rotation transmission mechanism that transmits rotation from the electric motor to the motion conversion mechanism. By incorporating a reverse input prevention clutch, when an axial component force acting on the movable sheave away from the fixed sheave is applied, the reverse input prevention clutch receives the rotational force (reverse input torque) transmitted from the movable sheave via the motion conversion mechanism. This makes it possible to maintain the axial position of the movable sheave against the axial component force of the force received from the transmission belt. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2007-263285 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, as described in Patent Document 1, when a reverse input prevention clutch is incorporated into the sheave actuator, a problem has been found in that when the movable sheave is moved axially away from the fixed sheave by the sheave actuator, the movable sheave may not move smoothly.

[0009] In other words, the reverse input prevention clutch of Patent Document 1 comprises an input shaft to which the rotation of an electric motor is input, an output shaft rotatably supported coaxially with the input shaft, an annular fixed outer ring surrounding the outer circumference of the output shaft, a plurality of pairs of rollers incorporated 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, a roller biasing spring that biases each pair of rollers in a direction that causes them to mesh between the cam surface and the cylindrical surface, a roller holder connected to the input shaft so as to rotate integrally with the input shaft, and a free-moving coupling portion that connects the input shaft and the output shaft with circumferential play.

[0010] This reverse input prevention clutch prevents the rollers from jamming between the cam surface and the cylindrical surface. When rotation is applied to the input shaft, the roller retainer, which rotates integrally with the input shaft, presses the rearmost roller in the direction of rotation forward in each pair of rollers. Therefore, the rotation of the input shaft is transmitted to the output shaft via the free-moving coupling, and the output shaft rotates integrally with the input shaft.

[0011] On the other hand, when rotation is input to the output shaft (i.e., when reverse input torque is applied to the reverse input prevention clutch), the cam surface on the outer circumference of the output shaft moves forward in the direction of rotation. As a result, the roller on the rear side of each pair of rollers engages between the cam surface and the cylindrical surface, preventing further rotation of the output shaft, and the output shaft becomes locked. Therefore, the transmission of rotation from the output shaft to the input shaft is prevented.

[0012] Subsequently, when rotation is input to the input shaft again, the roller holder, which rotates integrally with the input shaft, presses the rearmost roller in the direction of rotation forward in each pair of rollers. This disengages the rearmost roller in the direction of rotation, releasing the lock on the output shaft. Then, the rotation of the input shaft is transmitted to the output shaft via the movable coupling, and the output shaft rotates integrally with the input shaft.

[0013] Here, the action of locking the output shaft due to the reverse input (the action of preventing the rotation of the output shaft) is a sudden action caused by the roller directly engaging with the cam surface on the outer circumference of the output shaft and the cylindrical surface on the inner circumference of the fixed outer ring, and the action of releasing the lock of the output shaft is also a sudden action caused by the roller disengaging from the direct engagement 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.

[0014] Therefore, when this reverse input prevention clutch is incorporated into the sheave actuator, there is a problem in that the movement of the movable sheave becomes unstable when the sheave actuator moves the movable sheave axially away from the fixed sheave.

[0015] In other words, when a reverse input prevention clutch is incorporated into a sheave actuator, the axial force acting on the movable sheave from the transmission belt is transmitted to the reverse input prevention clutch via a motion conversion mechanism, so the output shaft of the reverse input prevention clutch is always subjected to reverse input torque.

[0016] On the other hand, when the sheave actuator moves the movable sheave axially away from the fixed sheave, the rotation of the electric motor is input to the input shaft of the reverse input prevention clutch, and the direction of this rotation is the same as the reverse input torque acting on the output shaft of the reverse input prevention clutch.

[0017] Therefore, when a sheave actuator moves a movable sheave axially away from a fixed sheave, a phenomenon may occur in which the output shaft locks due to the rotational speed of the output shaft of the reverse input prevention clutch exceeding the rotational speed of the input shaft, and then the output shaft unlocks due to the rotational speed of the input shaft exceeding the rotational speed of the output shaft, repeating alternately.

[0018] In the reverse input prevention clutch described in Patent Document 1, the output shaft lock operation is a sudden movement due to the direct engagement of the rollers, and similarly, the output shaft unlock operation is also a sudden movement due to the direct disengagement of the rollers. As a result, it was found that the axial movement of the movable sheave away from the fixed sheave becomes an intermittent movement of alternating acceleration and deceleration, which may prevent the movable sheave from moving smoothly.

[0019] Therefore, in order to resolve this problem, the applicant of the present application has already proposed the following configuration as a reverse input prevention clutch with a gradual locking and unlocking operation of the output shaft (Japanese Patent Application No. 2024-35788).

[0020] The input axis to which rotation is input, An output shaft is rotatably supported coaxially with the input shaft, An annular fixed outer ring surrounding the outer circumference of the output shaft, A plurality of segmented outer rings are arranged adjacently in the circumferential direction along the inner circumference of the fixed outer ring, It has a plurality of one-sided rollers and a plurality of other-sided rollers incorporated between the inner circumference of the plurality of divided outer rings and the outer circumference of the output shaft, On the outer circumference of the output shaft, there are a plurality of one-sided cam surfaces that form a wedge-shaped space that narrows toward one side in the circumferential direction between them and the divided outer ring, and a plurality of other-sided cam surfaces that form a wedge-shaped space that narrows toward the other side in the circumferential direction between them and the divided outer ring. The one-side roller is positioned between the one-side cam surface and the divided outer ring, and the other-side roller is positioned between the other-side cam surface and the divided outer ring. A roller biasing spring is provided that biases each of the aforementioned one-side rollers to one side in the circumferential direction, and biases each of the aforementioned other-side rollers to the other side in the circumferential direction. The input shaft is provided with a other-side roller pressing portion that moves together with the input shaft when the input shaft rotates in one direction in the circumferential direction to push the other-side roller in one direction in the circumferential direction, and a one-side roller pressing portion that moves together with the input shaft when the input shaft rotates in the other direction in the circumferential direction to push the one-side roller in the other direction in the circumferential direction. A reverse input prevention clutch is provided with a free-moving coupling portion between the input shaft and the output shaft, which connects the two with circumferential play.

[0021] In this configuration of the reverse input prevention clutch, when rotation is input to the input shaft in one direction in the circumferential direction, the other side roller pressing part, which moves integrally with the input shaft, pushes the other side roller in the circumferential direction, preventing the other side roller from engaging with the other side roller between the other side cam surface on the outer circumference of the output shaft and the split outer ring. When the input shaft rotates in one direction in the circumferential direction beyond the range of circumferential play of the free-moving coupling, the rotation of the input shaft is transmitted to the output shaft via the free-moving coupling, and the output shaft rotates integrally with the input shaft in one direction in the circumferential direction. Similarly, when rotation is input to the input shaft in the other direction in the circumferential direction, the output shaft rotates integrally with the input shaft in the other direction in the circumferential direction.

[0022] On the other hand, when rotation to one side in the circumferential direction is input to the output shaft (that is, when reverse input torque acts), the other-side cam surface on the outer circumference of the output shaft moves toward one side in the circumferential direction. Therefore, the other-side roller becomes engaged between the other-side cam surface on the outer circumference of the output shaft and the split outer ring, and the engagement of the other-side roller presses the split outer ring radially outward. The outer circumference of the split outer ring is friction-engaged with the inner circumference of the fixed outer ring, and the frictional engagement brakes the rotation of the output shaft toward one side in the circumferential direction, bringing the output shaft into a locked state. Therefore, transmission of rotation from the output shaft to the input shaft is blocked.

[0023] Thereafter, when rotation to one side in the circumferential direction is input to the input shaft, the other-side roller pressing portion that moves integrally with the input shaft presses the other-side roller toward one side in the circumferential direction. Therefore, the engagement of the other-side roller between the other-side cam surface on the outer circumference of the output shaft and the split outer ring is released, and the frictional engagement between the outer circumference of the split outer ring and the inner circumference of the fixed outer ring is canceled. The cancellation of the frictional engagement allows rotation of the output shaft toward one side in the circumferential direction, bringing the output shaft into an unlocked state. Thereafter, the rotation of the input shaft is transmitted to the output shaft via the floating connection portion, and the output shaft rotates integrally with the input shaft toward one side in the circumferential direction.

[0024] Similarly, when rotation to the other side in the circumferential direction is input to the output shaft, the one-side roller becomes engaged between the one-side cam surface on the outer circumference of the output shaft and the split outer ring. The engagement of the one-side roller presses the split outer ring radially outward, the outer circumference of the split outer ring is friction-engaged with the inner circumference of the fixed outer ring, and the frictional engagement brakes the rotation of the output shaft toward the other side in the circumferential direction. Then, when rotation to the other side in the circumferential direction is subsequently input to the input shaft, the one-side roller pressing portion presses the one-side roller toward the other side in the circumferential direction. Therefore, the engagement of the one-side roller between the one-side cam surface on the outer circumference of the output shaft and the split outer ring is released, the frictional engagement between the outer circumference of the split outer ring and the inner circumference of the fixed outer ring is canceled, and the output shaft rotates integrally with the input shaft toward the other side in the circumferential direction.

[0025] Here, when rotation is input to the output shaft (i.e., when reverse input torque is applied to the reverse input prevention clutch), instead of directly engaging the roller between the cam surface on the outer circumference of the output shaft and the inner circumference of the fixed outer ring, one side roller or the other side roller is engaged between the cam surface on the outer circumference of the output shaft and the split outer ring, and the outer circumference of the split outer ring is frictionally engaged with the inner circumference of the fixed outer ring to brake the rotation of the output shaft, so the locking operation of the output shaft is gradual. Similarly, when unlocking the output shaft, the frictional engagement between the outer circumference of the split outer ring and the inner circumference of the fixed outer ring is released, allowing the output shaft to rotate, so the unlocking operation of the output shaft is gradual compared to the case where the direct engagement of the roller between the cam surface on the outer circumference of the output shaft and the inner circumference of the fixed outer ring is released.

[0026] Therefore, when this reverse input prevention clutch configuration is used in a sheave actuator, when the sheave actuator moves the movable sheave axially away from the fixed sheave, the axial movement of the movable sheave is less likely to be an intermittent motion of alternating acceleration and deceleration, allowing the movable sheave to move smoothly.

[0027] As described above, a reverse input prevention clutch, which has multiple segmented outer rings arranged along the inner circumference of a fixed outer ring, locks the output shaft by frictionally engaging the outer circumference of the segmented outer rings with the inner circumference of the fixed outer ring when a reverse input torque is applied to the output shaft. This has the advantage that the locking and unlocking operations of the output shaft are gradual.

[0028] Here, when the inventors of the present invention conducted prototype evaluation of the above-mentioned reverse input prevention clutch, in which multiple segmented outer rings are provided along the inner circumference of a fixed outer ring, they encountered a problem in which the locking operation of the output shaft became unstable by chance.

[0029] When the inventors of this invention investigated the cause of the problem, they found that if the circumferential position of one roller or the other roller happens to coincide with the boundary position between adjacent circumferentially spaced outer rings, the roller can become stuck at the boundary between adjacent circumferentially spaced outer rings. As a result, the roller can no longer engage between the outer circumference of the output shaft and the outer ring, which may lead to unstable locking of the output shaft.

[0030] The problem this invention aims to solve is to provide a reverse input prevention clutch that ensures stable locking of the output shaft. [Means for solving the problem]

[0031] To solve the above problems, this invention provides a reverse input prevention clutch with the following configuration. [Configuration 1] The input axis to which rotation is input, An output shaft is rotatably supported coaxially with the input shaft, An annular fixed outer ring surrounding the outer circumference of the output shaft, A plurality of segmented outer rings are arranged adjacently in the circumferential direction along the inner circumference of the fixed outer ring, It has a plurality of one-sided rollers and a plurality of other-sided rollers incorporated between the inner circumference of the plurality of divided outer rings and the outer circumference of the output shaft, On the outer circumference of the output shaft, there are a plurality of one-sided cam surfaces that form a wedge-shaped space that narrows toward one side in the circumferential direction between them and the divided outer ring, and a plurality of other-sided cam surfaces that form a wedge-shaped space that narrows toward the other side in the circumferential direction between them and the divided outer ring. The one-side roller is positioned between the one-side cam surface and the divided outer ring, and the other-side roller is positioned between the other-side cam surface and the divided outer ring. A roller biasing spring is provided that biases each of the aforementioned one-side rollers to one side in the circumferential direction, and biases each of the aforementioned other-side rollers to the other side in the circumferential direction. The input shaft is provided with a other-side roller pressing portion that moves together with the input shaft when the input shaft rotates in one direction in the circumferential direction to push the other-side roller in one direction in the circumferential direction, and a one-side roller pressing portion that moves together with the input shaft when the input shaft rotates in the other direction in the circumferential direction to push the one-side roller in the other direction in the circumferential direction. A movable coupling is provided between the input shaft and the output shaft, connecting them with circumferential play. A reverse input prevention clutch in which the circumferential end faces of each divided outer ring are inclined with respect to the axial direction, such that the boundaries between adjacent divided outer rings in the circumferential direction extend diagonally with respect to the axial direction.

[0032] With this configuration, the boundaries between adjacent segmented outer rings in the circumferential direction extend diagonally to the axial direction, rather than parallel to the axial direction. This prevents one roller or the other roller from getting stuck in the boundary between adjacent segmented outer rings in the circumferential direction. As a result, the engagement of one roller or the other roller between the outer circumference of the output shaft and the segmented outer rings becomes stable, and the locking operation of the output shaft when reverse input torque is applied becomes stable.

[0033] [Configuration 2] The reverse input prevention clutch according to configuration 1, wherein the inclination angle of the circumferential end face of the divided outer ring with respect to the axial direction is set to 10° or more.

[0034] With this configuration, the large inclination angle of the circumferential end faces of the divided outer rings prevents the direction of the rollers from becoming oblique to the axial direction even when one or the other rollers skew and their direction becomes axial. Therefore, it is possible to effectively prevent one or the other roller from becoming stuck in the boundary between adjacent divided outer rings in the circumferential direction.

[0035] [Configuration 3] The plurality of one-sided rollers and the plurality of other-sided rollers are arranged alternately in the circumferential direction. A reverse input prevention clutch according to configuration 1 or 2, wherein the circumferential length of each divided outer ring is set such that two or more of the one-side rollers and two or more of the other-side rollers are located radially inward of each divided outer ring.

[0036] With this configuration, the circumferential length of the divided outer ring is set so that two or more rollers on one side and two or more rollers on the other side are located radially inward of each divided outer ring. Therefore, when a reverse input torque acts on the output shaft, two or more rollers on one side or two or more rollers on the other side engage between the outer circumference of the output shaft and the divided outer ring, and two or more rollers spaced apart in the circumferential direction press one divided outer ring radially outward. As a result, the frictional engagement between the outer circumference of the divided outer ring and the inner circumference of the fixed outer ring becomes more stable.

[0037] [Structure 4] An input-side bearing that rotatably supports the input shaft, An output-side bearing that rotatably supports the output shaft, A reverse input prevention clutch according to any one of configurations 1 to 3, further comprising an intermediate bearing that connects the input shaft and the output shaft so as to be rotatable relative to each other.

[0038] With this configuration, the input shaft, supported by the input-side bearing, and the output shaft, supported by the output-side bearing, are further connected via an intermediate bearing, ensuring that the axes of the input shaft and the output shaft are precisely aligned. As a result, the relative positional relationship between the cam surface on one side and the cam surface on the other side, and the roller pressing portion on one side and the roller pressing portion on the other side, becomes stable, leading to more stable locking and unlocking operations of the output shaft.

[0039] [Composition 5] The input side housing into which the input side bearing is assembled, The output side housing to which the output side bearing is assembled further comprises The input-side housing and the output-side housing have inner housing surfaces that face each other in the axial direction with the plurality of divided outer rings in between. The reverse input prevention clutch according to configuration 4, wherein the axial movement of the plurality of divided outer rings is restricted by the inner surface of the input side housing and the inner surface of the output side housing.

[0040] By adopting this configuration, the axial movement of the divided outer ring is restricted by the inner surfaces of the input-side housing and the output-side housing, which are facing each other axially with the divided outer ring in between. This prevents skew of one side roller or the other side roller due to the axial displacement of the divided outer ring.

[0041] [Composition 6] Multiple planes are formed on the outer circumference of the output shaft, each having a shape obtained by cutting a portion of the outer circumference of the output shaft in a straight line, and are arranged in the circumferential direction. A reverse input prevention clutch according to any one of configurations 1 to 5, wherein the one-sided cam surface and the other-sided cam surface are a portion on one side in the circumferential direction and a portion on the other side in the circumferential direction, respectively, of the circumferential center of each plane.

[0042] By adopting this configuration, it becomes possible to form one cam surface and the other cam surface with high precision at a low cost. [Effects of the Invention]

[0043] In this invention, the reverse input prevention clutch has a boundary between adjacent circumferentially adjacent divided outer rings that extends diagonally with respect to the axial direction, rather than parallel to the axial direction. This prevents one roller or the other roller from engaging with the boundary between adjacent circumferentially adjacent divided outer rings. As a result, the engagement of one roller or the other roller between the outer circumference of the output shaft and the divided outer ring is stable, and the locking operation of the output shaft when reverse input torque is applied is stable. [Brief explanation of the drawing]

[0044] [Figure 1] Cross-sectional view of a reverse input prevention clutch according to an embodiment of this invention. [Figure 2] Cross-sectional view along line II-II in Figure 1 [Figure 3]Figure 1 shows an exploded perspective view of the input shaft, split outer ring, and output shaft. [Figure 4] Figure 1 shows the boundary between the divided outer rings, viewed from the radially outer side. [Figure 5] Figure 2 shows the maximum skew angle of the roller. [Figure 6] A magnified view of a portion of Figure 2. [Figure 7] Figure 6 shows the state where the input shaft shown in Figure 1 is rotated in one direction in the circumferential direction. [Modes for carrying out the invention]

[0045] Figure 1 shows a reverse input prevention clutch according to an embodiment of the present invention. This reverse input prevention clutch comprises an input shaft 1 to which rotation is input, an output shaft 2 rotatably supported coaxially with the input shaft 1, an annular fixed outer ring 3 surrounding the outer circumference of the output shaft 2, a plurality of partially annular segmented outer rings 4 incorporated between the inner circumference of the fixed outer ring 3 and the outer circumference of the output shaft 2, and one-sided rollers 5a and the other-sided rollers 5b (see Figure 2) incorporated between the inner circumference of the segmented outer rings 4 and the outer circumference of the output shaft 2.

[0046] The input shaft 1 is rotatably supported by an input-side bearing 7 mounted on the input-side housing 6, and the output shaft 2 is rotatably supported by an output-side bearing 9 mounted on the output-side housing 8. Furthermore, the input shaft 1 and the output shaft 2 are connected to each other so as to be rotatable relative to each other by an intermediate bearing 10 mounted between them.

[0047] The axial direction is the direction parallel to the central axis of the input shaft 1 (the central axis of rotation), the radial direction is the direction perpendicular to the central axis of the input shaft 1, and the circumferential direction is the direction along the circumference of the circle centered on the central axis of the input shaft 1.

[0048] The fixed outer ring 3 is a non-rotating member that is fixed in place so as not to rotate. Here, the fixed outer ring 3 is formed integrally with the output side housing 8, but the fixed outer ring 3 may also be formed separately from the output side housing 8 and fixed to the output side housing 8.

[0049] An inner circumferential friction surface 11 is formed on the inner circumference of the fixed outer ring 3, facing radially from the outer circumference of the divided outer ring 4. The inner circumferential friction surface 11 is an annular surface that is continuous in the circumferential direction over its entire circumference. Here, the inner circumferential friction surface 11 employs a cylindrical surface with a constant inner diameter along the axial direction. The cylindrical center of the inner circumferential friction surface 11 coincides with the center of the output shaft 2.

[0050] As shown in Figure 2, an outer peripheral friction surface 12 is formed on the outer circumference of the divided outer ring 4. The outer peripheral friction surface 12 is the surface that frictionally engages with the inner peripheral friction surface 11 of the fixed outer ring 3 when the divided outer ring 4 is pressed radially outward by the engagement of one side roller 5a or the other side roller 5b. The outer peripheral friction surface 12 is a surface that extends circumferentially over an angular range corresponding to a part of the circumference, and in this case, it is a partial cylindrical surface obtained by dividing a cylindrical surface in the circumferential direction. The radius of curvature of the outer peripheral friction surface 12 is set to be between 97% and 100% of the radius of the inner peripheral friction surface 11 of the fixed outer ring 3. On the inner circumference of the divided outer ring 4, a partially cylindrical divided inner peripheral surface 13 is formed, having the center of curvature at the same position as the center of curvature of the outer peripheral friction surface 12.

[0051] Multiple segmented outer rings 4 are provided so as to be arranged circumferentially along the entire circumference of the inner friction surface 11 of the fixed outer ring 3. All of the segmented outer rings 4 are identical in shape, and the circumferential lengths of each segmented outer ring 4 are equal to each other. The circumferential length of each segmented outer ring 4 is the length to which two or more (two in the figure) one-sided rollers 5a and two or more (two in the figure) other-sided rollers 5b are located radially inward of each segmented outer ring 4. In the figure, the central angle of each segmented outer ring 4 is set to be the size obtained by dividing 360° into four equal parts in the circumferential direction (specifically, a size between 87° and 90°), but the central angle of each segmented outer ring 4 may also be the size obtained by dividing 360° into three equal parts in the circumferential direction (specifically, a size between 117° and 120°).

[0052] As shown in Figures 3 and 4, each segmented outer ring 4 is arranged adjacent to each other in the circumferential direction with a small gap between them to allow radial movement of each segmented outer ring 4. As shown in Figure 4, the circumferential end face 14 of each segmented outer ring 4 is inclined with respect to the axial direction such that, when viewed from the radial direction, the boundary between adjacent segmented outer rings 4 extends obliquely with respect to the axial direction. The inclination angle α of the circumferential end face 14 of the segmented outer ring 4 with respect to the axial direction is set to 10° or more (preferably 15° or more), and it is preferable to set it to be greater than the maximum skew angle β (β = 25° in the figure) of one side roller 5a or the other side roller 5b shown in Figure 5.

[0053] As shown in Figure 1, the input housing 6 and the output housing 8 have inner housing surfaces 15 and 16 that face each other axially with the divided outer ring 4 in between. Both the inner housing surface 15 of the input housing 6 and the inner housing surface 16 of the output housing 8 are planes perpendicular to the axial direction. The axial distance between the inner housing surface 15 of the input housing 6 and the inner housing surface 16 of the output housing 8 is set to be slightly larger than the axial width of the divided outer ring 4 (for example, set to a size such that the axial play of the divided outer ring 4 is less than 0.5 mm), so that each divided outer ring 4 is allowed to move circumferentially and radially while its axial movement is restricted.

[0054] As shown in Figure 6, one cam surface 17a and the other cam surface 17b are formed on the outer circumference of the output shaft 2, aligned in the circumferential direction. The one cam surface 17a faces radially opposite the divided inner circumferential surface 13 of the divided outer ring 4, forming a wedge-shaped space between it and the divided inner circumferential surface 13 that gradually narrows toward one side in the circumferential direction (right side in the figure). The other cam surface 17b also faces radially opposite the divided inner circumferential surface 13 of the divided outer ring 4, forming a wedge-shaped space between it and the divided inner circumferential surface 13 that gradually narrows toward the other side in the circumferential direction (left side in the figure). The one cam surface 17a and the other cam surface 17b are, in this context, the parts on one side in the circumferential direction and the parts on the other side in the circumferential direction of a plane shaped like a straight line cut out from a part of the outer circumference of the output shaft 2 when viewed from the axial direction, respectively.

[0055] The roller 5a on one side and the roller 5b on the other side are arranged alternately in the circumferential direction, corresponding to the cam surface 17a on one side and the cam surface 17b on the other side. The roller 5a on one side is positioned between the cam surface 17a on one side and the divided inner circumferential surface 13 of the divided outer ring 4, and the roller 5b on the other side is positioned between the cam surface 17b on the other side and the divided inner circumferential surface 13 of the divided outer ring 4. Both the roller 5a on one side and the roller 5b on the other side are rollers with cylindrical surfaces, and are assembled with their roller axes oriented axially. The diameter of the roller 5a on one side and the diameter of the roller 5b on the other side are equal.

[0056] A roller biasing spring 18 is provided between one side roller 5a and the other side roller 5b. The roller biasing spring 18 is compressed and incorporated between one side roller 5a and the other side roller 5b, and its elastic restoring force biases one side roller 5a to one side in the circumferential direction (right side in the figure) and the other side roller 5b to the other side in the circumferential direction (left side in the figure). Due to the biasing force of this roller biasing spring 18, one side roller 5a is in a state where it is simultaneously in contact with one side cam surface 17a and the divided inner circumferential surface 13 of the divided outer ring 4, and the other side roller 5b is also in a state where it is simultaneously in contact with the other side cam surface 17b and the divided inner circumferential surface 13 of the divided outer ring 4.

[0057] As shown in Figure 2, multiple rollers 5a are provided on one side, corresponding to the number of cam surfaces 17a on one side (eight in the figure), and multiple rollers 5b are also provided on the other side, corresponding to the number of cam surfaces 17b on the other side (eight in the figure).

[0058] As shown in Figures 1 and 2, the input shaft 1 is provided with a column portion 19 that extends axially between the outer circumference of the output shaft 2 and the inner circumference of the divided outer ring 4. As shown in Figures 1 and 3, the column portion 19 is connected to the input shaft 1 so as to move circumferentially together with the input shaft 1 when the input shaft 1 rotates. In Figures 1 and 3, the column portion 19 is formed integrally with the input shaft 1, but the column portion 19 may be formed separately from the input shaft 1 and fixed to the input shaft 1.

[0059] As shown in Figure 6, each column portion 19 is positioned in the circumferential direction opposite to one side (right side in the figure) of the one-side roller 5a and corresponding to the other side (left side in the figure) of the other-side roller 5b. Here, the other end (left end in the figure) of the column portion 19 opposite to one side (right side in the figure) of the one-side roller 5a constitutes the one-side roller pressing portion 20a, and the other end (right end in the figure) of the column portion 19 opposite to the other side (left side in the figure) of the other-side roller 5b constitutes the other-side roller pressing portion 20b. The one-side roller pressing portion 20a is the part that moves together with the input shaft 1 when the input shaft 1 rotates in the other circumferential direction (left side in the figure) and pushes the one-side roller 5a in the other circumferential direction (left side in the figure), and the other-side roller pressing portion 20b is the part that moves together with the input shaft 1 when the input shaft 1 rotates in one circumferential direction (right side in the figure) and pushes the other-side roller 5b in the one circumferential direction (right side in the figure). The one-side roller pressing portion 20a faces the one circumferential side (right side in the figure) of the one-side roller 5a with a small gap between them, and the other-side roller pressing portion 20b also faces the other circumferential side (left side in the figure) of the other-side roller 5b with a small gap between them.

[0060] As shown in Figures 1 and 2, a movable coupling portion 21 is provided between the input shaft 1 and the output shaft 2, connecting them with circumferential play. In this case, the movable coupling portion 21 consists of a recess 22 provided on the input shaft 1 and a protrusion 23 provided on the output shaft 2 (in the figures, the protrusion from the round hole of a pin press-fitted into a round hole). As shown in Figures 6 and 7, the protrusion 23 engages with the recess 22 with a circumferential gap.

[0061] The movable coupling portion 21 connects the input shaft 1 and the output shaft 2 in such a way that when the input shaft 1 shown in Figure 1 rotates relative to the output shaft 2, the rotation angle of the input shaft 1 with respect to the output shaft 2 is within the range of circumferential play (the circumferential gap between the convex portion 23 and the concave portion 22 shown in Figure 6), and no transmission of rotation from the input shaft 1 to the output shaft 2 occurs. On the other hand, when the rotation angle of the input shaft 1 with respect to the output shaft 2 exceeds the range of circumferential play (the circumferential gap between the convex portion 23 and the concave portion 22 shown in Figure 6), the rotation of the input shaft 1 is transmitted to the output shaft 2, and the output shaft 2 rotates integrally with the input shaft 1.

[0062] The amount of circumferential play in the movable coupling portion 21 (the size of the circumferential gap between the convex portion 23 and the concave portion 22 shown in Figure 6) is set so that when the input shaft 1 shown in Figure 6 rotates to one side in the circumferential direction (to the right in the figure) and the other side roller pressing portion 20b contacts the other side roller 5b, the inner end surface of the concave portion 22 in the circumferential direction does not yet contact the convex portion 23, leaving circumferential play. Similarly, when the input shaft 1 rotates to the other side in the circumferential direction (to the left in the figure) and the one side roller pressing portion 20a contacts the one side roller 5a, the inner end surface of the concave portion 22 in the circumferential direction does not yet contact the convex portion 23, leaving circumferential play. Here, the input shaft 1 is provided with a concave portion 22 and the output shaft 2 is provided with a convex portion 23, but this can also be reversed, with the input shaft 1 providing a convex portion 23 and the output shaft 2 providing a concave portion 22.

[0063] As shown in Figure 7, when rotation is input to the input shaft 1 in one circumferential direction (to the right in the figure), the reverse input prevention clutch prevents the other side roller 5b from engaging with the other side roller 5b between the other side cam surface 17b on the outer circumference of the output shaft 2 and the split outer ring 4. When the input shaft 1 rotates in one circumferential direction (to the right in the figure) beyond the range of circumferential play of the free coupling part 21, the rotation of the input shaft 1 is transmitted to the output shaft 2 via the free coupling part 21, causing the output shaft 2 to rotate in one circumferential direction (to the right in the figure) together with the input shaft 1. Similarly, when rotation is input to the input shaft 1 in the other circumferential direction (to the left in the figure), the output shaft 2 also rotates in the other circumferential direction (to the left in the figure) together with the input shaft 1.

[0064] On the other hand, when rotation is input to the output shaft 2 shown in Figure 6 in one circumferential direction (to the right in the figure) (i.e., when a reverse input torque is applied), the other cam surface 17b on the outer circumference of the output shaft 2 moves to the other circumferential direction (to the right in the figure). As a result, the other roller 5b engages between the other cam surface 17b on the outer circumference of the output shaft 2 and the split outer ring 4. This engagement of the other roller 5b presses the split outer ring 4 radially outward, causing the partially annular outer circumferential friction surface 12 of the split outer ring 4 to frictionally engage with the annular inner circumferential friction surface 11 of the fixed outer ring 3. This frictional engagement brakes the rotation of the output shaft 2 to one circumferential direction (to the right in the figure), and the output shaft 2 becomes locked. Therefore, the transmission of rotation from the output shaft 2 to the input shaft 1 is prevented.

[0065] Subsequently, when rotation is input to the input shaft 1 in one circumferential direction (to the right in the figure), the other side roller pressing part 20b, which moves integrally with the input shaft 1, presses the other side roller 5b in one circumferential direction (to the right in the figure). As shown in Figure 7, the engagement of the other side roller 5b between the other side cam surface 17b on the outer circumference of the output shaft 2 and the split outer ring 4 is released, and the frictional engagement between the outer circumference friction surface 12 of the split outer ring 4 and the inner circumference friction surface 11 of the fixed outer ring 3 is released. This release of frictional engagement allows the output shaft 2 to rotate in one circumferential direction (to the right in the figure), and the lock on the output shaft 2 is released. Subsequently, the rotation of the input shaft 1 is transmitted to the output shaft 2 via the floating coupling part 21, and the output shaft 2 rotates integrally with the input shaft 1 in one circumferential direction (to the right in the figure).

[0066] Similarly, when rotation is input to the output shaft 2 in the other circumferential direction (left side in the figure) as shown in Figure 6, the one-side roller 5a engages between the one-side cam surface 17a on the outer circumference of the output shaft 2 and the divided outer ring 4. This engagement of the one-side roller 5a presses the divided outer ring 4 radially outward, causing the partially annular outer circumferential friction surface 12 of the divided outer ring 4 to frictionally engage with the annular inner circumferential friction surface 11 of the fixed outer ring 3. This frictional engagement brakes the rotation of the output shaft 2 in the other circumferential direction (left side in the figure). Then, when rotation is input to the input shaft 1 in the other circumferential direction (left side in the diagram), the one-side roller pressing part 20a presses the one-side roller 5a in the other circumferential direction (left side in the diagram), disengaging the one-side roller 5a from the one-side cam surface 17a on the outer circumference of the output shaft 2 and the split outer ring 4, releasing the frictional engagement between the outer circumference friction surface 12 of the split outer ring 4 and the inner circumference friction surface 11 of the fixed outer ring 3, and the output shaft 2 rotates together with the input shaft 1 in the other circumferential direction (left side in the diagram).

[0067] Here, when rotation is input to the output shaft 2 shown in Figure 6 (i.e., when reverse input is applied to the reverse input prevention clutch), instead of directly engaging the rollers 5a and 5b between the cam surfaces 17a and 17b on the outer circumference of the output shaft 2 and the inner circumference of the fixed outer ring 3, one side roller 5a or the other side roller 5b is engaged between the cam surfaces 17a and 17b on the outer circumference of the output shaft 2 and the split outer ring 4, and the rotation of the output shaft 2 is braked by frictionally engaging the partially annular outer friction surface 12 of the split outer ring 4 with the annular inner friction surface 11 of the fixed outer ring 3, so that the locking operation of the output shaft 2 is gradual. Similarly, when unlocking the output shaft 2, the friction engagement between the outer peripheral friction surface 12 of the split outer ring 4 and the inner peripheral friction surface 11 of the fixed outer ring 3 is released, allowing the output shaft 2 to rotate. This results in a gentler unlocking operation of the output shaft 2 compared to releasing the direct engagement of the rollers 5a and 5b between the cam surfaces 17a and 17b on the outer circumference of the output shaft 2 and the inner circumference of the fixed outer ring 3.

[0068] Furthermore, as shown in Figures 3 and 4, this reverse input prevention clutch has boundaries between adjacent circumferentially adjacent divided outer rings 4 that extend diagonally with respect to the axial direction, rather than parallel to the axial direction. This prevents one side roller 5a or the other side roller 5b, as shown in Figure 6, from engaging with the boundaries between adjacent circumferentially adjacent divided outer rings 4. As a result, the engagement of one side roller 5a or the other side roller 5b between the outer circumference of the output shaft 2 and the divided outer rings 4 is stable, and the locking operation of the output shaft 2 when reverse input torque is applied is stable.

[0069] Furthermore, as shown in Figures 3 and 4, the boundaries between adjacent circumferentially adjacent divided outer rings 4 extend diagonally with respect to the axial direction, which has the advantage of preventing the roller biasing spring 18 shown in Figure 6 from getting stuck in the boundaries between the divided outer rings 4.

[0070] Furthermore, because the inclination angle α of the circumferential end face 14 of the divided outer ring 4 shown in Figure 4 is large, this reverse input prevention clutch can prevent the direction of one roller 5a or the other roller 5b from becoming the same direction as the extending boundary between the divided outer rings 4 shown in Figure 4, even when the roller skews and its direction becomes oblique to the axial direction, as shown in Figure 5. Therefore, it is possible to effectively prevent one roller 5a or the other roller 5b from becoming stuck in the boundary between circumferentially adjacent divided outer rings 4. Note that Figure 5 shows the roller skewed to its limit, but the actual skew angle of the roller is only a few degrees or less.

[0071] Furthermore, as shown in Figure 2, the reverse input prevention clutch is configured such that the circumferential length of the divided outer ring 4 is set so that two or more rollers 5a on one side and two or more rollers 5b on the other side are located radially inward of each divided outer ring 4. Therefore, when a reverse input torque acts on the output shaft 2, two or more rollers 5a on one side or two or more rollers 5b on the other side engage between the outer circumference of the output shaft 2 and the divided outer ring 4, and two or more rollers 5a (or 5b) that are spaced apart in the circumferential direction press one divided outer ring 4 radially outward. As a result, the frictional engagement between the outer circumference of the divided outer ring 4 and the inner circumference of the fixed outer ring 3 is stable when a reverse input torque acts on the reverse input prevention clutch.

[0072] Furthermore, as shown in Figure 1, this reverse input prevention clutch connects the input shaft 1, supported by the input-side bearing 7, and the output shaft 2, supported by the output-side bearing 9, via an intermediate bearing 10. This ensures that the axis of the input shaft 1 and the axis of the output shaft 2 are reliably aligned. As a result, the relative positional relationship between the one-side cam surface 17a and the other-side cam surface 17b shown in Figure 6, and the one-side roller pressing portion 20a and the other-side roller pressing portion 20b is stable, and the locking and unlocking operations of the output shaft 2 are stable.

[0073] Furthermore, as shown in Figure 1, this reverse input prevention clutch restricts the axial movement of the divided outer ring 4 between the inner surface 15 of the input-side housing 6 and the inner surface 16 of the output-side housing 8, which are facing each other axially with the divided outer ring 4 in between. This makes it possible to prevent skew of one-side roller 5a or the other-side roller 5b due to the axial displacement of the divided outer ring 4.

[0074] Furthermore, as shown in Figure 2, this reverse input prevention clutch uses the outer surface of the output shaft 2 as the one-sided cam surface 17a and the other-sided cam surface 17b, making it possible to form the one-sided cam surface 17a and the other-sided cam surface 17b with high precision at a low cost.

[0075] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0076] 1 input axis 2 Output shafts 3 Fixed outer ring 4-part outer ring 5a One-sided roller 5b Other side roller 6 Input side housing 7 Input side bearing 8 Output side housing 9 Output side bearing 10 Intermediate bearings 14 Circumferential end face 15,16 Housing interior 17a One-sided cam surface 17b Other side cam surface 18. Roller-equipped spring 20a One-sided roller pressing section 20b Other side roller pressing section 21 Movable coupling section α Incline angle

Claims

1. The input shaft (1) to which rotation is input, The output shaft (2) is rotatably supported coaxially with the input shaft (1), The annular fixed outer ring (3) surrounds the outer circumference of the output shaft (2), A plurality of segmented outer rings (4) are arranged adjacent to each other in the circumferential direction along the inner circumference of the fixed outer ring (3), It has a plurality of one-sided rollers (5a) and a plurality of other-sided rollers (5b) incorporated between the inner circumference of the plurality of divided outer rings (4) and the outer circumference of the output shaft (2), On the outer circumference of the output shaft (2), there are a plurality of one-side cam surfaces (17a) that form a wedge-shaped space that narrows toward one side in the circumferential direction between them and the divided outer ring (4), and a plurality of other-side cam surfaces (17b) that form a wedge-shaped space that narrows toward the other side in the circumferential direction between them and the divided outer ring (4). The one-side roller (5a) is positioned between the one-side cam surface (17a) and the divided outer ring (4), and the other-side roller (5b) is positioned between the other-side cam surface (17b) and the divided outer ring (4). A roller biasing spring (18) is provided that biases each of the one side rollers (5a) to one side in the circumferential direction and biases each of the other side rollers (5b) to the other side in the circumferential direction. The input shaft (1) is provided with a other-side roller pressing portion (20b) that moves together with the input shaft (1) when the input shaft (1) rotates in one direction in the circumferential direction to push the other-side roller (5b) in one direction in the circumferential direction, and a one-side roller pressing portion (20a) that moves together with the input shaft (1) when the input shaft (1) rotates in the other direction in the circumferential direction to push the one-side roller (5a) in the other direction in the circumferential direction. A movable connecting part (21) is provided between the input shaft (1) and the output shaft (2) to connect them with circumferential play. A reverse input prevention clutch in which the circumferential end faces (14) of each divided outer ring (4) are inclined with respect to the axial direction, such that the boundaries between adjacent divided outer rings (4) in the circumferential direction extend diagonally with respect to the axial direction.

2. The reverse input prevention clutch according to claim 1, wherein the inclination angle (α) of the circumferential end face (14) of the divided outer ring (4) with respect to the axial direction is set to 10° or more.

3. The plurality of one-sided rollers (5a) and the plurality of other-sided rollers (5b) are arranged alternately in the circumferential direction. The reverse input prevention clutch according to claim 1 or 2, wherein the circumferential length of each divided outer ring (4) is set such that two or more of the one-side rollers (5a) and two or more of the other-side rollers (5b) are located radially inward of each divided outer ring (4).

4. The input side bearing (7) rotatably supports the input shaft (1), The output side bearing (9) rotatably supports the output shaft (2), The reverse input prevention clutch according to claim 1 or 2, further comprising an intermediate bearing (10) that connects the input shaft (1) and the output shaft (2) so as to be rotatable relative to each other.

5. The input side housing (6) into which the input side bearing (7) is assembled, The output side housing (8) to which the output side bearing (9) is assembled further comprises The input side housing (6) and the output side housing (8) have housing inner surfaces (15, 16) that face each other in the axial direction with the plurality of divided outer rings (4) in between. The reverse input prevention clutch according to claim 4, wherein the axial movement of the plurality of divided outer rings (4) is restricted by the inner surface (15) of the input side housing (6) and the inner surface (16) of the output side housing (8).

6. Multiple planes are formed on the outer circumference of the output shaft (2), each having a shape obtained by cutting a portion of the outer circumference of the output shaft (2) in a straight line, and are arranged in the circumferential direction. The reverse input prevention clutch according to claim 1 or 2, wherein the one-sided cam surface (17a) and the other-sided cam surface (17b) are a portion on one side in the circumferential direction and a portion on the other side in the circumferential direction, respectively, from the circumferential center of each plane.

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