Cam clutch

Abstract

To provide a cam clutch which has a simple structure, is free from the need of control with high accuracy, can improve stability of clutch operation and obtain high responsibility with small drive power when compulsorily changing the posture of a cam, and has a high degree-of-freedom in mode switching.SOLUTION: A cam clutch which includes a plurality of cams 140 supported by a cage member 150 between an inner ring 110 and an outer ring 120 and arranged in a circumferential direction is configured such that the plurality of cams 140 are arranged in a plurality of rows in a rotary shaft direction; control of a rotation angle relative to the inner ring 110 or the outer ring 120 fixed with the cage member 150 is possible; a selector 170 having a cam posture control surface 171 capable of changing a posture by contacting a cam surface of the cam 140 corresponding to at least one row is provided; and the cam posture control surface 171 has a cam release part 173 for changing a posture of not operating the cam 140 in a form of projecting from a cam operation part 172 to a radial direction cam 140 side.SELECTED DRAWING: Figure 2

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, if the cam engagement force remains, a large driving force is required to change the cam's position, and there is a risk that switching will not be smooth when torque is being transmitted between the inner and outer rings. In addition, there is a risk of damaging the inner and outer ring raceway surfaces, and the mechanism and actuator for changing the cam position must be enlarged in accordance with the driving force.

[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 with a simple configuration, which does not require high-precision control, requires a small driving force when forcibly changing the cam position, improves the stability of clutch operation, provides high responsiveness, and provides a high degree of freedom in mode switching. [Means for solving the problem]

[0008] The present invention provides a cam clutch comprising an inner ring, an outer ring, a plurality of cams, and a cage member, the inner ring and the outer ring being rotatable relative to each other on the same axis, and an annular space being defined between the inner ring and the outer ring in which the plurality of cams can be arranged in the circumferential direction, the cage member being fixed to the outer ring or the inner ring in the rotational direction and configured to support the plurality of cams, the cage member being provided with a selector capable of controlling the rotation angle relative to the outer ring or the inner ring to which the cage member is fixed in the rotational direction, the plurality of cams being arranged in a plurality of rows in the rotational axis direction, the selector having a plurality of position change parts capable of respectively changing the position of the cams in the plurality of cam rows, the position change parts corresponding to the cams in at least one row having a cam position control surface that comes into contact with a cam surface on the outer peripheral side or the inner peripheral side of the cam and can change the position of the cam, the cam position control surface having a cam operating part that allows the cam to be in a position in which torque can be transmitted, and a position change part that has a shape that protrudes radially from the cam operating part toward the cam and allows the cam to be in a position in which torque cannot be transmitted, The above problem is solved by providing a cam release surface that changes the position. [Effects of the Invention]

[0009] According to the invention of claim 1, multiple cams are arranged in multiple rows in the direction of the rotation axis, and the selector has multiple attitude change units that can change the attitude of the cams in the multiple cam rows, respectively.This makes it possible to change the attitude of the cams in the multiple rows by rotating a single selector, and multiple modes can be performed by controlling the rotation angle of a single selector. Furthermore, for at least one row of cams, the cam attitude control surface can come into contact with the cam surface to change the cam attitude, and by having a cam operating portion and a cam releasing portion that protrudes radially toward the cam from the cam operating portion and changes the cam to an inoperative position, the cam operation can be released at any position on the cam releasing portion, so there is no need to align the positions for multiple cams with high precision, and there is also no need for high-precision control of the rotation angle of the selector.

[0010] Furthermore, in the row corresponding to the cam attitude control surface, the driving force required to forcibly change the cam attitude is small, which allows the parts and actuators used for switching to be miniaturized and manufactured at low cost, while improving the stability of clutch operation and achieving high responsiveness, and improving durability by not damaging the inner and outer ring raceway surfaces. Furthermore, because the row corresponding to the cam attitude control surface is switched by riding over the end face of the cam, the selector switching angle can be made large without requiring highly precise control, enabling reliable operation without being affected by dimensional tolerances or control errors. Furthermore, this allows the cam operation in the row corresponding to the cam attitude control surface to be released while the selector for mode switching in the other rows is still permitted, thereby improving the degree of freedom in combining multiple modes that can be switched by rotating a single selector.

[0011] According to the configuration of claim 2, when the first row cam is in a locked state, the selector does not need to receive torque, so the structure of the selector can be simplified and durability is further improved. According to the invention of claim 3, both the first row cams and the second row cams correspond to the cam attitude control surface, so that highly accurate control of the rotation angle of the selector is not required in all modes. According to the invention of claim 4, it is possible to switch modes for two independent inner rings with one selector. According to the invention of claim 5, different shape By including the cam, it is possible to optimally match the torque transmission characteristics, response speed characteristics, etc., even if they differ for each mode switched by the selector. According to the configuration of claim 6, a spacing member is provided between the inner and outer rings of at least one row so as to maintain the distance between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. As the spacing member has a concentricity maintaining function, other bearing members can be omitted, making the system more compact in the axial direction, and the axial centers of the inner and outer rings are aligned with high precision, reducing variation in the operation of the multiple cams and further improving the stability of clutch operation. [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 an exploded perspective view of the cam clutch shown in FIG. 1. [Figure 3] FIG. 2 is a cross-sectional view of the cam clutch shown in FIG. 1. [Figure 4] 2 is an explanatory diagram of the operation of the cam clutch shown in FIG. 1; [Figure 5] 6A and 6B are explanatory views of the operation of a cam clutch according to a second embodiment of the present invention. [Figure 6] 10A and 10B are explanatory views of the operation of a cam clutch according to a third embodiment of the present invention. [Figure 7] 10A and 10B are explanatory views of the operation of a cam clutch according to a fourth 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 7. However, the present invention is not limited to these embodiments. [Example]

[0014] As shown in Figures 1 to 3, 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 can control the rotation angle relative to the outer ring 120. The multiple cams 140 are arranged in two rows, a first row cams 141 and a second row cams, in the direction of the rotation axis, and the first row cams and the second row cams are arranged so as to form one-way clutches in opposite directions. The selector 170 has a pressing portion 175 which is a position changing portion that can change the position of the first row cam 141, and a cam position control surface 171 which is a position changing portion that can change the position of the second row cam 142.

[0015] The cam attitude control surface 171 has a cam operating portion 172 that allows the second row cam 142 to operate normally, and a cam release portion 173 that protrudes radially toward the second row cam 142 from the cam operating portion 172 and changes the second row cam 142 to an inoperative position. In this embodiment, the cam surface of the second row cam 142 on the outer ring 120 side is configured to contact only the cam attitude control surface 171 of the selector 170 and not the inner peripheral surface of the outer ring 120, but it may also be configured so that a portion of the rotation axis direction contacts the inner peripheral surface of the outer ring 120.

[0016] The cam pressing portion 175 has multiple axially extending pin-shaped portions that correspond to the first row cams 141, and is configured to be able to change the posture of the first row cams 141 by pressing the side of the first row cams 141 circumferentially as the selector 170 rotates. In this embodiment, the cam pressing portion 175 is formed as a separate part from the selector body 175, and is configured so that the cam pressing portion 175 and the selector body 175 rotate together during use to function as the selector 170. The cam surface of the first row cam 141 on the outer ring 120 side is configured to be able to contact only the outer ring 120, and the cam surface on the inner ring 110 side is configured to be able to contact only the inner ring 110, and as the selector 170 rotates, the cam pressing portion 175 presses the side of the first row cam 141, changing the position of the first row cam 141 to one in which it is not in operation. The selector 170 is driven to rotate relative to the outer ring 120 by an actuator 180, and is configured so that the rotation angle relative to the outer ring 120 can be controlled. In this embodiment, the outer ring 120 and the actuator 180 are fixed to a fixed portion, and the relative rotation angle between the outer ring 120 and the selector 170 is controlled by the actuator 180.

[0017] As shown in Figure 4, the cam clutch 100 according to this embodiment can be switched between a 2-way free state in which the inner ring 110 is allowed to rotate relative to the outer ring 120 in both directions, a 1-way locked state in which rotation in one direction is allowed and rotation in the opposite direction is prohibited, and a 2-way locked state in which rotation in both directions is prohibited, depending on the rotation angle of the selector 170. In the 2-way free state (lower right side of Figure 4: 0° position), the cam surface of the second row cam 142 on the outer ring 120 side comes into contact with the cam release portion 173 of the cam attitude control surface 171 of the selector 170, so that the second row cam 142 is kept in an attitude in which it does not operate as a one-way clutch, and the side surface of the first row cam 141 on the inner ring 110 side is pressed by the cam pressing portion 175 of the selector 170, so that the first row cam 141 is kept in an attitude in which it does not operate as a one-way clutch.

[0018] In the one-way lock state (lower center of Figure 4: position -α°), the cam surface of the second row cam 142 on the outer ring 120 side comes into contact with the cam release portion 173 of the cam attitude control surface 171 of the selector 170, keeping the second row cam 142 in an attitude in which it does not operate as a one-way clutch, and the cam pressing portion 175 of the selector 170 moves away from the side surface of the first row cam 141 on the inner ring 110 side, causing the first row cam 141 to assume an attitude in which it operates as a one-way clutch. In the 2-way lock state (lower left side of Figure 4: position -α-α°), the cam surface of the second row cam 142 on the outer ring 120 side comes into contact with the cam operating portion 172 of the cam attitude control surface 171 of the selector 170, causing the second row cam 142 to assume a position in which it operates as a one-way clutch, and the cam pressing portion 175 of the selector 170 moves away from the side of the first row cam 141 on the inner ring 110 side, causing the first row cam 141 to assume a position in which it operates as a one-way clutch. [Example]

[0019] As shown in FIG. 5, the cam clutch according to the second embodiment of the present invention is configured such that a first row cam 141 and a second row cam 142 are arranged on either side of a selector 170, and a portion of the cam surface of the first row cam 141 on the inner ring 110 side comes into contact with a cam attitude control surface 171b, which is an attitude change portion that can change the attitude of the first row cam 141 of the selector 170. In the 2-way free state (lower right side of Figure 5: 0° position), the cam surface of the second row cam 142 on the outer ring 120 side comes into contact with the cam release portion 173 of the cam attitude control surface 171 of the selector 170, maintaining the second row cam 142 in a position where it does not operate as a one-way clutch, and a portion of the cam surface of the first row cam 141 on the inner ring 110 side comes into contact with the cam release portion 173b of the cam attitude control surface 171b of the selector 170, maintaining the first row cam 141 in a position where it does not operate as a one-way clutch.

[0020] In the one-way lock state (lower center of Figure 5: position -α°), the cam surface of the second row cam 142 on the outer ring 120 side comes into contact with the cam release portion 173 of the cam attitude control surface 171 of the selector 170, maintaining the second row cam 142 in an attitude in which it does not operate as a one-way clutch, and the cam surface of the first row cam 141 on the inner ring 110 side moves away from the cam release portion 173b of the cam attitude control surface 171b of the selector 170 and becomes able to come into contact with the outer peripheral surface on the inner ring 110 side, thereby placing the first row cam 141 in an attitude in which it operates as a one-way clutch. In the 2-way lock state (lower left side of Figure 5: position -α-α°), the cam surface of the second row cam 142 on the outer ring 120 side comes into contact with the cam operating portion 172 of the cam attitude control surface 171 of the selector 170, and the second row cam 142 assumes a position in which it operates as a one-way clutch, and the cam surface of the first row cam 141 on the inner ring 110 side moves away from the cam release portion 173b of the cam attitude control surface 171b of the selector 170 and becomes able to come into contact with the outer peripheral surface on the inner ring 110 side, and the first row cam 141 assumes a position in which it operates as a one-way clutch. In this embodiment, it is also possible to reverse the direction in which rotation in the 1-way lock state is prevented by shortening the circumferential length of the cam release portion 173 relative to the second row cam 142 and lengthening the circumferential length of the cam release portion 173b relative to the first row cam 141. [Example]

[0021] As shown in FIG. 6, the cam clutch according to the third embodiment of the present invention has a second inner ring 112 and a second outer ring 122 on the opposite side of the rotation axis direction from the selector 170 of the cam clutch 100 of the first embodiment described above, and a third row cam 143 is arranged between them. The second outer ring 122 is fixed to a fixed portion in the same manner as the outer ring 120 , and the second inner ring 112 is configured to be rotatable independently of the inner ring 110 . A part of the cam surface of the third row cam 143 on the second inner ring 112 side is configured to come into contact with a cam attitude control surface 171c which is an attitude changing portion that can change the attitude of the third row cam 143 of the selector 170. As in the first embodiment described above, the rotation of the inner ring 110 can be switched between a 2-way free state (second from the right in the bottom row of Figure 6: 0° position), a 1-way locked state (second from the left in the bottom row of Figure 6: -α° position), and a 2-way locked state (left side of the bottom row of Figure 6: -α-α° position).

[0022] In these positions, a portion of the cam surface of the third row cam 143 on the second inner wheel 112 side comes into contact with the cam release portion 173c of the cam attitude control surface 171c of the selector 170, so that the third row cam 143 is maintained in an attitude in which it does not operate as a one-way clutch, and the second inner wheel 112 is in a two-way free state in which it can rotate freely. Then, when the rotation of the inner ring 110 is in a 2-way free state and the second inner ring 112 is in a 2-way free state (second from the right in the bottom row of Figure 6: 0° position), and the selector 170 is rotated in the opposite direction (bottom right in Figure 6: +α° position), the cam surface of the third row cam 143 on the second inner ring 112 side moves away from the cam release portion 173c of the cam attitude control surface 171c of the selector 170 and becomes able to come into contact with the outer peripheral surface on the second inner ring 112 side, and the third row cam 143 assumes an attitude that allows it to operate as a one-way clutch. At this time, if the cam pressing portion 175, which presses the side of the first row cam 141, presses it beyond the limit of the position change of the first row cam 141, it is desirable to provide an elastic mechanism or the like that pushes back the cam pressing portion 175 as shown by the arrow in Figure 6 and does not press the side of the first row cam 141 more than necessary. [Example]

[0023] As shown in FIG. 7, the cam clutch according to the fourth embodiment of the present invention has a second inner ring 112 and a second outer ring 122 provided on the opposite side of the selector 170 in the rotational axis direction from the second row cam 142 of the cam clutch of the second embodiment described above, with a third row cam 143 disposed between them. The second outer ring 122 is fixed to a fixed portion in the same manner as the outer ring 120 , and the second inner ring 112 is configured to be rotatable independently of the inner ring 110 . A part of the cam surface of the third row cam 143 on the second outer ring 122 side is configured to come into contact with a cam attitude control surface 171d, which is an attitude changing portion that can change the attitude of the third row cam 143 of the selector 170. As in the second embodiment described above, the rotation of the inner ring 110 can be switched between a 2-way free state (second from the right in the bottom row of Figure 7: 0° position), a 1-way locked state (second from the left in the bottom row of Figure 7: -α° position), and a 2-way locked state (left side of the bottom row of Figure 7: -α-α° position).

[0024] In these positions, a portion of the cam surface of the third row cam 143 on the second outer ring 122 side comes into contact with the cam release portion 173d of the cam attitude control surface 171d of the selector 170, so that the third row cam 143 is maintained in an attitude in which it does not operate as a one-way clutch, and the second inner ring 112 is in a two-way free state in which it can rotate freely. Then, when the rotation of the inner ring 110 is in a 2-way free state and the second inner ring 112 is in a 2-way free state (second from the right in the bottom row of Figure 7: 0° position), and the selector 170 is rotated in the opposite direction (bottom right in Figure 7: +α° position), the cam surface on the second outer ring 122 side of the third row cam 143 moves away from the cam release portion 173d of the cam attitude control surface 171c of the selector 170 and becomes able to come into contact with the inner surface on the second outer ring 122 side, and the third row cam 143 assumes an attitude that allows it to operate as a one-way clutch.

[0025] 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 180 is assumed to be a motor with a worm gear that meshes with the outer periphery of the selector 170, but it may be any motor that rotates the selector 170 relative to the outer ring 120 and the second outer ring 122. In addition, in the third and fourth embodiments, there is a second inner ring that can rotate independently, but there may be three or more inner rings that rotate independently, and depending on the number, the number of cam rows may also be four or more. In addition, a plurality of rollers may be arranged on the same circumference as the cam between the inner and outer rings as spacing members, and the spacing members may be block members arranged to slide against the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, or the spacing members may be fixed to the cage member 150 or formed integrally with the cage member 150. Furthermore, the cams in each row may have different shapes depending on the required torque resistance and the like. Furthermore, the inner ring may be fixed to a fixed portion, and the rotation angle of the selector relative to the inner ring may be controlled. [Explanation of symbols]

[0026] 100 ··· Cam clutch 110 ··· Inner circle 112 ··· Second inner ring 120 Outer ring 122 Second outer ring 140 Cam 141 First row cam 142 Second row cam 143 Third row cam 150 Cage member 170 ··· Selector 171 ··· Cam attitude control surface 172 Cam operating part 173 Cam release part 175 Cam pressing part 176 ··· Selector body 180 ··· Actuator

Claims

1. A bearing comprising an inner ring, an outer ring, a plurality of cams and a cage member, the inner ring and the outer ring are coaxially rotatable relative to each other, and an annular space is defined between the inner ring and the outer ring in which the plurality of cams can be disposed in a circumferential direction; The cage member is a cam clutch configured to be fixed to the outer ring or the inner ring in a rotational direction and to support the plurality of cams, a selector capable of controlling a rotation angle of the cage member relative to the outer ring or the inner ring fixed in a rotational direction; The plurality of cams are arranged in a plurality of rows in the direction of the rotation axis, the selector has a plurality of attitude change units that can change the attitudes of the cams of the plurality of cam trains, the attitude change portion corresponding to at least one row of cams has a cam attitude control surface that comes into contact with an outer peripheral side or an inner peripheral side cam surface of the cam and can change the attitude of the cam, a cam clutch characterized in that the cam attitude control surface has a cam operating portion that allows the cam to take a position in which torque can be transmitted, and a cam release portion that protrudes radially toward the cam from the cam operating portion and changes the cam to a position in which torque cannot be transmitted.

2. the plurality of cams are arranged in at least two rows including a first row and a second row in the rotation axis direction; the cam surface on the outer periphery of the first row cam can only come into contact with the outer ring, and the cam surface on the inner periphery can only come into contact with the inner ring, a cam surface on the outer circumferential side or the inner circumferential side of the second row cam is capable of contacting the cam attitude control surface of the selector; 2. The cam clutch according to claim 1, wherein the selector has a position changing portion formed of a cam pressing portion that can change the position of the first row cam by pressing a side surface of the first row cam in a circumferential direction.

3. the plurality of cams are arranged in at least two rows including a first row and a second row in the rotation axis direction; an outer peripheral cam surface of the first row cam can come into contact only with the outer ring, and an inner peripheral cam surface can come into contact with the cam attitude control surface of the selector; 2. A cam clutch according to claim 1, wherein the cam surface on the inner periphery of the second row cam can contact only the inner ring, and the cam surface on the outer periphery can contact the cam attitude control surface of the selector.

4. the plurality of cams are arranged in at least three rows including first to third rows in the rotation axis direction, the inner ring has a first inner ring capable of contacting the first row cam and the second row cam, and a second inner ring rotatable independently of the first inner ring and capable of contacting the third row cam, 4. A cam clutch according to claim 2, wherein the cam surface on the outer circumferential side or the inner circumferential side of the third row cam is capable of coming into contact with the cam attitude control surface of the selector.

5. 5. The cam clutch according to claim 1, wherein the plurality of cams include cams of different shapes.

6. 6. A cam clutch according to claim 1, further comprising a spacing member disposed between the inner ring and the outer ring of at least one row so as to maintain a gap between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring.

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