Cam clutch

Abstract

To provide a cam clutch that has a simple configuration, eliminates the need for highly accurate control, can operate with small drive power, and is less likely to damage a cam surface and inner and outer ring raceway surfaces.SOLUTION: A cam clutch includes: a plurality of cams 140 supported to a cage member 150 between an inner ring 110 and an outer ring 120 and disposed in a circumferential direction; and a selector capable of changing postures of the cams 140. The selector includes: a driven part 171 capable of controlling a rotation angle relative to the inner ring 110 or the outer ring 120 to which a cage member 150 is fixed; and a selector body part 175 elastically displaceable by an elastic mechanism together with the driven part 171 in the circumferential direction. The selector body part 175 includes a cam posture control protrusion part coming into contact with the cams 140 and capable of changing the postures of the cams 140.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a cam clutch that is switchable between a free state that allows relative rotation between an outer ring and an inner ring, and a locked state that prohibits relative rotation between the outer ring and the inner ring. [Background technology]

[0002] As a clutch that controls the transmission and interruption of rotational force, a cam clutch is known that forcibly changes the position of a cam or sprag to switch between a locked state that prohibits relative rotational movement between the inner and outer rings (transmits rotational force) and a free state that allows relative rotational movement between the inner and outer rings (interrupts rotational force).

[0003] For example, Patent Document 1 discloses a device that has a cam posture changer equipped with multiple pin members as a means for forcibly tilting multiple cams arranged circumferentially between an inner ring and an outer ring, and the pin members move circumferentially relative to each other to press the side surfaces of the cams circumferentially, thereby forcibly changing the posture of the cams. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6882699 Summary of the Invention [Problem to be solved by the invention]

[0005] In these cam clutches, when switching from a locked state to a free state, a large driving force is required to change the position of the cam while torque is being transmitted by the cam, and there is a risk that switching while torque is being transmitted could place a large burden on the drive source. Furthermore, the mechanism and actuator for changing the cam position must be enlarged in size in accordance with the driving force, which may damage the cam surface and the inner and outer ring raceway surfaces.

[0006] The cam clutch known from Patent Document 1 is highly responsive and can secure the desired torque capacity, and since the pin member is positioned away from the pin tilting center, it is possible to generate a fairly large driving force to change the cam posture; however, it is necessary to secure the relative positions of each pin with high precision, and it is also necessary to control the rotation angle of the cam posture change part with high precision when changing the cam posture.

[0007] The present invention aims to solve these problems by providing a cam clutch that has a simple configuration, does not require high-precision control, can operate with a small driving force, and causes little damage to the cam surface or inner and outer ring raceway surfaces. [Means for solving the problem]

[0008] The present invention provides a cam clutch comprising an inner ring and an outer ring arranged coaxially and rotatably relative to each other, a plurality of cams arranged circumferentially between the inner ring and the outer ring, a cage member fixed in the rotational direction to the inner ring or the outer ring and supporting the plurality of cams, and a selector capable of changing the attitude of the cam, wherein the selector comprises a driven part capable of controlling the rotation angle relative to the inner ring or the outer ring to which the cage member is fixed in the rotational direction, and a selector main body part elastically displaceable in the circumferential direction relative to the driven part, and the selector main body part has a cam attitude protrusion that comes into contact with the cam and can change the attitude of the cam, thereby solving the above problem. [Effects of the Invention]

[0009] According to the invention of claim 1, the selector comprises a driven part capable of controlling the relative rotation angle with the inner ring or outer ring to which the cage member is fixed in the rotational direction, and a selector main body part that is elastically displaceable in the circumferential direction relative to the driven part, thereby eliminating the need for highly precise control of the rotation angle of the driven part. Furthermore, if there is residual torque in the clutch, the elasticity reduces the residual torque, allowing the cam position to be controlled below a specified torque value, requiring only a small driving force and causing little damage to the cam surface or inner and outer ring raceway surfaces.

[0010] According to the configuration of claim 2, elastic displacement in the circumferential direction can be achieved with a simple structure. According to the configuration invention of claim 3, one of the selector main body and the driven part has a circumferential elongated hole, and the other has a positioning pin that fits into the elongated hole to regulate the displacement angle between the selector main body and the driven part.This makes it possible to regulate the amount of deformation of the elastic member within a predetermined range, preventing bending or twisting due to excessive deformation of the elastic member and improving the durability of the selector.

[0011] According to the configuration of claim 4, the cam attitude control convex portion is arranged so as to be able to come into contact with the cam at a position in the rotational axis direction that is different from the cam surface that comes into contact with the inner or outer ring of the cam. This allows the selector switching angle to be large without having to be controlled with high precision, and enables reliable operation without being affected by dimensional tolerances or control errors. According to the configuration of claim 5, multiple sets of inner rings, outer rings, multiple cams, and cage members are arranged in the direction of the rotation axis on either side of the selector, and the selector has a selector main body portion for each of the cams on both sides of the rotation axis, so that one selector can be driven to control the operation of the cam clutches on both sides at its rotational position, making it possible to switch between multiple states with a simple configuration. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view of a cam clutch according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of the cam clutch shown in FIG. 1 with the case removed. [Figure 3] 3 is a perspective view of the cam clutch shown in FIG. 2 with the inner and outer rings removed. [Figure 4] 4 is a perspective view of the cam clutch shown in FIG. 3 with a cage and an actuator removed. [Figure 5] FIG. 2 is a perspective view of a selector of the cam clutch shown in FIG. 1 . [Figure 6] FIG. 6 is a perspective view of a driven part of the selector shown in FIG. 5; [Figure 7]FIG. 4 is a perspective view of the selector body of the cam clutch according to the first embodiment of the present invention, viewed from another direction. [Figure 8] 1 is a cross-sectional perspective view of a cam clutch according to a first embodiment of the present invention. [Figure 9] 5A and 5B are explanatory diagrams illustrating the operation of the cam clutch of the present invention. [Figure 10] FIG. 6 is a cross-sectional perspective view of a cam clutch according to a second embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional perspective view of a cam clutch according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Examples of the present invention will be described with reference to Figures 1 to 11. However, the present invention is not limited to these embodiments. [Example]

[0014] As shown in Figures 1 to 8, the cam clutch 100 according to the first embodiment of the present invention comprises an inner ring 110 and an outer ring 120 that are arranged on the same axis and are capable of relative rotation, a plurality of cams 140 that transmit and block power between the inner ring 110 and the outer ring 120, a cage member 150 that is fixed in the rotational direction to the outer ring 120 and supports the plurality of cams 140, and a selector 170 that has a cam attitude control protrusion 176 that can control the rotation angle relative to the outer ring 120, comes into contact with the cam surface of the cam 140, and can change the attitude of the cam 140. Furthermore, between the inner ring 110 and the outer ring 120, there are provided a plurality of rollers 149 which are arranged to roll on the outer peripheral surface of the inner ring 110 and the inner peripheral surface of the outer ring 120 as spacing members, and the plurality of cams 140 and the plurality of rollers 149 are supported by a cage member 150 at predetermined intervals in the circumferential direction on the same circumference.

[0015] Furthermore, the plurality of cams 140 and the plurality of rollers 149 are biased toward the inner ring 110 by a biasing means 130 . The spacing member may be a block member arranged to slide against the outer peripheral surface of the inner ring 110 and the inner peripheral surface of the outer ring 120, the spacing member may be fixed to the cage member 150 or formed integrally with the cage member 150, or no spacing member may be provided. In this embodiment, the case 101 is provided on the outer peripheral side of the outer ring 120, and the outer ring 120 is engaged with the rotation fixing notch 102 of the case 101 and fixed to the case 101 in the circumferential direction. Additionally, the cage member 150 engages with the outer ring 120 and is fixed relative to the outer ring 120 in the circumferential direction.

[0016] The selector 170 includes a driven part 171 whose rotation angle can be controlled, and a selector body part 175 that can be elastically displaced in the circumferential direction relative to the driven part 171 by an elastic mechanism. The selector body 175 has a cam attitude control protrusion 176 that comes into contact with the cam 140 and can change the attitude of the cam 140 . The elastic mechanism consists of an elastic member accommodating portion 172 provided in the driven portion 171, a spring 173 accommodated in the elastic member accommodating portion 172, and a compression pin 177 provided in the selector main body portion 175 and inserted into the elastic member accommodating portion 172. The cam attitude control protrusion 176 is disposed so as to be able to come into contact with the cam 140 at a position in the rotation axis direction that is different from the cam surface that comes into contact with the outer ring 120 of the cam 140 . In this embodiment, the cam surface of the cam 140 on the outer ring 120 side is configured so that most of the rotational axis direction contacts the inner surface of the outer ring 120, and a portion of the rotational axis direction contacts the cam attitude control protrusion 176 of the selector main body 175. The driven part 171 of the selector 170 is rotationally driven by the actuator 190, and is configured so that the rotation angle relative to the outer ring 120 can be controlled.

[0017] The cam 140 is arranged so that the entire inner cam surface faces the outer circumferential surface of the inner ring 110, a portion of the outer cam surface can come into contact with the cam attitude control protrusion 176 of the selector main body 175, and the majority of the outer cam surface faces the inner circumferential surface of the outer ring 120. The actuator 190, which rotates the case 101 and the driven part 171 of the selector 170, is fixed to a fixed part not shown, so that the relative rotation angle between the outer ring 120 and the cage member 150 and the driven part 171 of the selector 170 is controlled by the actuator 190. In addition, the selector main body 175 has a circumferential elongated hole 178, and the driven part 171 has a positioning pin 174 that fits into the elongated hole 178 to regulate the displacement angle between the selector main body 175 and the driven part 171, ensuring coaxial rotation of the selector main body 175 and the driven part 171 and suppressing bending and twisting due to deformation of the spring 173 housed in the elastic member housing part 172.

[0018] The cam clutch 100 of this embodiment can be switched between a free state in which relative rotational movement of the inner ring 110 and the outer ring 120 in both directions is permitted, and a locked state in which relative rotational movement of the inner ring 110 and the outer ring 120 in one direction is prohibited, depending on the rotation angle of the driven part 171 of the selector 170. The operation when switching from the locked state to the free state will be described with reference to FIG. In the locked state, as shown in (a), the cam attitude control protrusion 176 is on standby at a position separated from the cam 140. The transition to the free state is achieved by the driven part 171 of the selector 170 rotating relative to the cage member 150, causing the elastic member accommodating part 172 to move to the left in the drawing, and the compression pin 177 moving to the left via the spring 173, causing the cam attitude control protrusion 176 of the selector main body part 175 of the selector 170 to push the side of the cam 140 to the left. During this movement, when transmission torque remains in the cam 140, as shown in (b), the spring 173 is compressed, causing the cam attitude control protrusion 176 to come into contact with the side of the cam 140 and stopping the movement of the selector main body 175 without interfering with the movement of the driven part 171.

[0019] When the torque transmitted to the cam 140 decreases or the compression force of the spring increases, as shown in (c), the cam attitude control protrusion 176 presses against the side of the cam 140, disengaging the cam, and the cam 140 is fixed in an attitude where it is not meshed between the outer peripheral surface of the inner ring 110 and the inner peripheral surface of the outer ring 120, and the inner ring 110 enters a free state where it is not restricted from rotating in either direction relative to the outer ring 120. Furthermore, even if the movement of the driven part 171 progresses from the state of (c), as shown in (d), the spring 173 is compressed, causing the cam attitude control protrusion 176 to push against the side of the cam 140, preventing the limit of the change in the attitude of the cam 140 from being exceeded, and there is no need to accurately control the rotation angle of the driven part 171 to stop it.

[0020] In this embodiment, two elastic member accommodating portions 172 and four positioning pins 174 are arranged at approximately equal angular intervals around the circumference of the driven portion 171, for a total of six locations, but the number and arrangement of these may be designed as appropriate. Furthermore, by forming the cam attitude control protrusion 176 of the selector main body 175 to protrude toward the center so as to come into contact with only a portion of the cam 140, and by arranging it so as to be able to come into contact with the cam 140 at a position in the rotational axis direction that is different from the cam surface that comes into contact with the outer ring 120 of the cam 140, the selector main body 175 can be formed integrally with the cam attitude control protrusion 176, making manufacturing easier; however, a pin may also be formed to protrude from the selector main body 175 so as to come into contact with the entire axial surface of the cam 140. [Example]

[0021] As shown in FIG. 10, in a cam clutch 100b according to a second embodiment of the present invention, a selector body 175b is configured such that the cam attitude control protrusion comes into contact with the inner ring 110 side of the cam 140 to change the attitude of the cam 140, and the cam surface on the inner ring 110b side of the cam 140 is configured so that most of the rotational axis direction of the cam surface contacts the outer peripheral surface of the inner ring 110b and part of the rotational axis direction contacts the cam attitude control protrusion of the selector body 175b. The other configurations are the same as those in the first embodiment. [Example]

[0022] As shown in FIG. 11, the cam clutch 100c according to the third embodiment of the present invention has inner rings 110L, 110R, outer rings 120L, 120R, a plurality of cams 140L, 140R, and cage members 150L, ​​150R arranged on both sides of the rotational axis direction across the driven part 171C of the selector, and has selector main bodies 175L, 175R for the cams on both sides of the rotational axis direction, respectively. In this embodiment, the selector main body 175L on the upper left side of the figure is configured, as in the first embodiment, so that the cam attitude control protrusion comes into contact with the outer ring 120L side of the cam 140L to change the attitude of the cam 140L, and the cam surface on the outer ring 120L side of the cam 140L is configured so that most of the rotational axis direction contacts the outer peripheral surface of the outer ring 120L and part of the rotational axis direction contacts the cam attitude control protrusion of the selector main body 175L.

[0023] Furthermore, as in the second embodiment, the selector main body 175R on the lower right side of the figure is configured so that the cam attitude control protrusion comes into contact with the inner ring 110R side of the cam 140R to change the attitude of the cam 140R, and the cam surface on the inner ring 110R side of the cam 140R is configured so that most of the rotational axis direction contacts the outer peripheral surface of the inner ring 110R and part of the rotational axis direction contacts the cam attitude control protrusion of the selector main body 175R. The selector main bodies 175L and 175R move in opposite directions to set the cams 140L and 140R in the free state, so that the cams can be independently switched to the free state by forward or reverse rotation of the driven part 171C of the selector.

[0024] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design modifications can be made without departing from the present invention as set forth in the claims. In each of the above embodiments, the illustrated actuator 190 is assumed to be a motor with a worm gear that meshes with the outer periphery of the driven parts 171, 171b, 171C, but it may be any motor that rotates the driven parts 171, 171b, 171C relative to the outer rings 120, 120b, 120L, 120R. [Explanation of symbols]

[0025] 100 ··· Cam clutch 101 ··· Case 102 Rotation fixing notch 110 ··· Inner circle 120 Outer ring 130..... biasing means 140 Cam 149 ··· Laura 150 Cage member 170 ··· Selector 171 Driven part 172 Elastic member storage section 173 Spring (elastic member) 174 Locating pin 175 Selector body 176 Cam attitude control protrusion 177 ··· Compression Pin 178 ··· Slot 190 Actuator

Claims

1. A cam clutch comprising an inner ring and an outer ring that are coaxially arranged so as to be rotatable relative to each other, a plurality of cams that are arranged in the circumferential direction between the inner ring and the outer ring, a cage member that is fixed to the inner ring or the outer ring in the rotational direction and supports the plurality of cams, and a selector that can change the attitude of the cams, the selector includes a driven part capable of controlling a relative rotation angle between the cage member and the inner ring or the outer ring to which the cage member is fixed in a rotational direction, and a selector body part that is elastically displaceable in a circumferential direction relative to the driven part by an elastic mechanism, The selector body has a cam attitude control protrusion that can change the attitude of the cam by contacting the cam.

2. 2. The cam clutch according to claim 1, wherein the elastic mechanism has an elastic member accommodating portion provided on one of the selector body portion and the driven portion, and a compression pin provided on the other of the selector body portion and inserted into the elastic member accommodating portion.

3. 2. The cam clutch according to claim 1, wherein one of the selector body and the driven part has a circumferentially elongated hole, and the other has a positioning pin that fits into the elongated hole to regulate the displacement angle between the selector body and the driven part.

4. 2. The cam clutch according to claim 1, wherein the cam attitude control protrusion is arranged so as to be able to come into contact with the cam at a position in the rotational axis direction different from a cam surface that contacts the inner ring or the outer ring of the cam.

5. a plurality of sets of the inner ring, the outer ring, the plurality of cams, and the cage member are provided in the rotation axis direction with the selector interposed therebetween; 5. A cam clutch according to claim 1, wherein the selector has selector body portions for the cams on both sides in the direction of the rotation axis.

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