cam clutch

Abstract

The present invention provides a cam clutch that can switch operating modes with a simple structure, has high responsiveness and can ensure the expected torque capacity, and whose structure is not complicated even if the outer ring is used as a rotating body, and can also reduce the axial dimension. Specifically, it has an operating mode switching mechanism (140) that can switch between any two or more of the following: an idle state that allows relative rotation in two directions, a one-way clutch state that allows relative rotation in either direction, and a locked state that prohibits relative rotation in two directions. The operating mode switching mechanism (140) has a cam attitude changing part (141) that can move axially independently of the rotation of the inner ring (110) and the outer ring (120). Multiple cams (131) have engagement parts (136) that are provided in a manner that protrude from the side toward the cam attitude changing part (141).

Description

Technical Field

[0001] The present invention relates to a cam clutch with an operation mode switching mechanism, wherein the operation mode switching mechanism can switch between any two or more of the following states: an idle state that allows relative rotational movement of the outer and inner rings in two directions; a one-way clutch state that allows relative rotational movement of the outer and inner rings in either forward or reverse direction; and a locked state that prohibits relative rotational movement of the outer and inner rings in two directions. Background Technology

[0002] As a clutch that controls the transmission and cut-off of rotational force, a bidirectional clutch is known that can switch between driving and idling in both the forward and reverse directions.

[0003] A certain bidirectional clutch is configured such that, by tilting a cam or wedge, it can switch between a locked state that prohibits relative rotation of the inner and outer rings (transmitting rotational force) and an idling state that allows relative rotation of the inner and outer rings (cutting off rotational force) (see, for example, Patent Document 1 and Patent Document 2).

[0004] Furthermore, Patent Document 3 describes a bidirectional clutch with a switching mechanism that controls a retainer to switch between three operating modes: bidirectional idling mode, unidirectional locking mode, and bidirectional locking mode. The retainer can hold the roller, which serves as a power transmission component, in a neutral position or an engaged position on the cam surface formed on the inner circumference of the outer ring.

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2011-220509

[0007] Patent Document 2: Japanese Patent Application Publication No. 11-182589

[0008] Patent Document 3: Japanese Patent Application Publication No. 2014-219015

[0009] Patent Document 4: Japanese Patent Application Publication No. 2020-190255 Summary of the Invention

[0010] Furthermore, in the bidirectional clutch described in Patent Document 1, the engagement and disengagement of the input-side rotating body and the output-side rotating body are switched by tilting the wedge in the same direction as the rotation of the input-side rotating body when the input-side rotating body rotates relative to the output-side rotating body. Therefore, there is a problem of poor responsiveness due to time loss during the switching of rotation directions. The same problem also exists in the bidirectional clutch described in Patent Document 2.

[0011] The two-way clutch described in Patent Document 3 can transmit power in two directions simultaneously using a leaf spring-like component. However, since power transmission is achieved through friction, there is a problem that the transmittable torque is relatively small relative to the size of the two-way clutch.

[0012] To solve such problems and to provide a cam clutch that can switch operating modes with a simple structure, is highly responsive, and can ensure the expected torque capacity, the applicant invented a cam clutch having the operating mode switching mechanism shown in Patent Document 4.

[0013] In the first, second, and fourth embodiments of the cam clutch described in Patent Document 4, there is a problem that when the outer ring is used as a rotating body, a complex mechanism is required to operate the operation mode switching mechanism from the fixed side.

[0014] Furthermore, in the third embodiment, a cam with a special shape is required, and there is also the problem of an increased axial dimension.

[0015] This invention is designed to solve these problems. The technical problem to be solved is to provide a cam clutch that can switch operating modes with a simple structure, has high responsiveness and can ensure the expected torque capacity, and whose structure does not become complicated even if the outer ring is used as a rotating body, and can also reduce the axial dimension.

[0016] This invention relates to a cam clutch comprising: at least one set of inner and outer rings configured to rotate relative to each other on the same axis; a plurality of cams disposed circumferentially between the inner and outer rings; and a force-applying unit that applies force to the plurality of cams in the radial direction. The invention addresses the aforementioned problem by providing a switching mechanism for at least two of the following operating modes: an idle state allowing relative rotation in both directions of the outer and inner rings; a one-way clutch state allowing relative rotation in either direction of the outer and inner rings; and a locked state prohibiting relative rotation in both directions of the outer and inner rings. The operating mode switching mechanism includes a cam attitude changing section that can move axially independently of the rotation of the inner and outer rings. A portion or all of the plurality of cams includes an engaging portion that protrudes laterally toward the cam attitude changing section.

[0017] According to the invention described in technical solution 1, the cam with the engaging portion can be tilted in a predetermined direction simply by moving the cam attitude changing part axially. Therefore, a high degree of responsiveness can be obtained when switching the operating mode of the cam clutch. Moreover, since the power transmission mechanism is composed of a cam, the torque capacity that can be transmitted is not limited by friction, thus ensuring the expected torque capacity.

[0018] Furthermore, since the cam tilts as the cam attitude changer moves and by limiting the radial position of the cam engagement part, there is no sliding noise between the cam attitude changer and the cam, nor is there noise when the cam contacts the track surface during the transition from the idle state to the locked state. Moreover, since the cam rolls against both the inner and outer track surfaces, no slippage occurs between the cam and the track surfaces, thus preventing idle wear between the cam and the inner or outer ring.

[0019] Furthermore, since the action mode switching mechanism is composed of a cam attitude change part and a locking part, the cam attitude change part can move axially independently of the rotation of the inner and outer rings, and the locking part is configured to protrude from the side of the cam towards the cam attitude change part. Therefore, a cam that is roughly the same as the existing cam can be used, and even if the outer ring is used as a rotating body, the structure will not be complicated, and the increase in axial dimension will be very small.

[0020] According to the configuration described in this technical solution 2, since the cam can be tilted by the axial movement of the cam attitude changing part, and the cam attitude can always be maintained even if the cam moves in the circumferential direction relative to the cam attitude changing part, the operation mode can be switched with a very simple configuration even if the outer ring is used as a rotating body.

[0021] According to the configuration described in technical solution 3, since the rotational directions of the engagement of the first cam and the second cam are different from each other, by changing the posture of either or both of the first cam and the second cam, the following four operating modes can be switched: a bidirectional freewheeling mode that allows rotation in both the forward and reverse directions, a unidirectional locking mode that only allows rotation relative to either the forward or reverse direction, and a bidirectional locking mode that prohibits rotation in both the forward and reverse directions.

[0022] According to the configuration described in technical solution 4, by setting a common operating mode switching mechanism in the center of two cam clutch mechanisms arranged in parallel in the axial direction, the number of parts can be reduced and the structure of the cam clutch can be simplified.

[0023] According to the configuration described in technical solution 5, by using a common action mode switching mechanism, the number of parts can be reduced and the structure of the cam clutch can be simplified.

[0024] According to the configuration described in technical solution 6, since the attitudes of the first cam and the second cam can be controlled by a common cam attitude change unit, the complexity and large size of the cam clutch structure can be avoided.

[0025] Furthermore, according to the invention involved in this technical solution 7, the posture of the first cam and the posture of the second cam can be selectively controlled by a common cam posture changing unit.

[0026] According to the configuration described in technical solution 8, a sufficiently high torque capacity can be ensured while suppressing the increase in axial dimension. Attached Figure Description

[0027] Figure 1 This is an exploded perspective view showing the configuration of the cam clutch according to the first embodiment of the present invention.

[0028] Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the cam clutch including the central shaft.

[0029] Figure 3 yes Figure 1 The top view of the cam clutch shown is a diagram showing the state after omitting the operating mode switching mechanism.

[0030] Figure 4 yes Figure 2 A partially enlarged view of the sectional view shown.

[0031] Figure 5 yes Figure 1 The diagram shows a three-dimensional view of the cam in the cam clutch.

[0032] Figure 6 yes Figure 1 The diagram shows a 3D view of the motion mode switching mechanism.

[0033] Figure 7 This is a diagram schematically illustrating the shape of the attitude change portion and the engagement portion of another embodiment of the cam clutch according to the first embodiment of the present invention.

[0034] Figure 8 This is a cross-sectional view of the cam clutch including the central shaft according to the second embodiment of the present invention.

[0035] Figure 9This is a cross-sectional view of the cam clutch including the central shaft according to the third embodiment of the present invention.

[0036] Symbol Explanation

[0037] 100, 200, 300 - Cam clutch; 110, 210, 310 - Inner ring; 120, 220, 320 - Outer ring; 131, 231, 331 - Cam; 131a - First cam; 131b - Second cam; 132 - Retaining groove; 136 - Engaging part; 140, 240, 340 - Operation mode switching mechanism; 141, 241, 341 - Cam posture changing part; 142, 242, 342 - Body part; 350 - Middle ring. Detailed Implementation

[0038] Reference Figures 1-9 Embodiments of the present invention will be described. However, the present invention is not limited to these embodiments.

[0039] Example 1

[0040] like Figure 1 and Figure 2 As shown, the cam clutch 100 according to the first embodiment of the present invention includes: an inner ring 110 and an outer ring 120, which are configured to rotate relative to each other on the same shaft; a cam mechanism disposed between the outer peripheral surface of the inner ring 110 and the inner peripheral surface of the outer ring 120, which are opposite to each other; and an operation mode switching mechanism 140 for switching the operation mode of the cam clutch 100.

[0041] The cam mechanism consists of multiple cams 131 and a force-applying unit (not shown). The multiple cams 131 are arranged circumferentially on the same circumference, and the force-applying unit is wound in a retaining groove 132 provided in the multiple cams 131, applying force radially inward. Preferably, the cams 131 are arranged with almost no clearance in the circumferential direction. By forming this configuration, a high torque transmission capacity can be achieved.

[0042] The cam mechanism described in this embodiment includes a first cam and a second cam that engage with each other in different directions of rotation. Hereinafter, unless specifically mentioned, the first cam and the second cam will be referred to as cam 131.

[0043] On the side of cam 131, as Figure 5 As shown, a engaging part 136 is provided in a prominent manner, which can engage with the cam posture changing part 141 of the action mode switching mechanism 140.

[0044] Although there are no special restrictions on the arrangement of the first and second cams in the cam mechanism, it is also as follows: Figure 3As shown, the first cam 131a and the second cam 131b are preferably arranged in an alternating manner. By forming this configuration, the attitudes of the first cam 131a and the second cam 131b can be controlled by a common operating mode switching mechanism 140, thus avoiding the complexity and large size of the cam clutch 100 structure. Furthermore, the attitudes of the first cam 131a and the second cam 131b can be controlled simultaneously.

[0045] Furthermore, the first cam 131a and the second cam 131b do not need to be arranged alternately on the same circumference. Therefore, the number of the first cam 131a and the second cam 131b can be the same or different.

[0046] For example, the first cam 131a and the second cam 131b have the same external shape, with engaging portions 136 provided only on different sides. The second cam 131b can be a cam that reverses the front and back of the first cam 131a. In addition, although the first cam 131a and the second cam 131b can also have different external shapes, by having the same external shape, the number of parts can be reduced.

[0047] The first cam 131a is configured, for example, to engage with the inner ring 110 and the outer ring 120 in friction when the outer ring 120 rotates in one direction, and to tilt in the direction of disengagement from the inner ring 110 and the outer ring 120 when the outer ring 120 rotates in another direction.

[0048] Therefore, the second cam 131b, which is used to reverse the inside and outside of the first cam 131a, is configured such that when the outer ring 120 rotates in another direction, it engages with the inner ring 110 and the outer ring 120, and when the outer ring 120 rotates in one direction, it tilts in the direction of disengagement from the inner ring 110 and the outer ring 120.

[0049] As a force-applying unit (not shown), for example, a ring-shaped garter spring can be used, and the garter spring is configured to connect the retaining grooves 132 of the first cam 131a and the second cam 131b.

[0050] The force-applying unit can be any elastic body that applies force to each of the multiple cams 131 in either a radially inward or radially outward direction. Alternatively, multiple leaf springs or torsion springs can also be used.

[0051] The cam clutch 100 according to this embodiment has an operation mode switching mechanism, which can switch between an idle state that allows relative rotation of the inner ring 110 and the outer ring 120 and a locked state that prohibits relative rotation of the inner ring 110 and the outer ring 120.

[0052] The operation mode switching mechanism 140 of this embodiment includes a cam posture changing part 141, which is configured to move axially independently of the rotation of the inner ring 110 and the outer ring 120, and to restrict the posture of the cam 131.

[0053] like Figure 2 , 4 As shown in Figures 6 and 7, the operation mode switching mechanism 140 of this embodiment includes: a ring-shaped body portion 142, which is configured to rotate relative to the inner ring 110 and the outer ring 120; and a cam posture changing portion 141, which is configured to be circumferentially oriented on the side of the cam 131 of the body portion 142, so that when it abuts against the engaging portion 136 of the cam 131, it slides with the engaging portion 136 while limiting the radial position of the engaging portion 136.

[0054] The cam attitude change unit 141 is configured to switch the fixed and released attitude of the cam 131 by moving the main body 142 axially.

[0055] The engaging part 136 is positioned such that the cam 131 will not simultaneously contact the inner ring 110 and the outer ring 120 by changing the radial direction position using the cam attitude changing part 141. For example, it is positioned further outward than the perpendicular line from the contact point between the cam 131 and the inner ring 110 and the cam 131.

[0056] Although the cam attitude changing part 141 is configured as a circumferential groove in this embodiment, as long as the attitude of the cam 131 can be fixed or released, the cam attitude changing part 141 can also be a protrusion on only one circumference on the inner circumference side, and can be any shape depending on the shape of the engaging part 136.

[0057] Furthermore, although in this embodiment the main body 142 is an annular plate and the cam attitude change part 141 is integrally formed, as long as the cam attitude change part 141 can move axially, it can also be rod-shaped or other shapes, and can also be separately formed independently from the cam attitude change part 141.

[0058] Furthermore, bearing rollers and the like can be appropriately configured between the inner ring 110 and the outer ring 120, in addition to the first cam 131a and the second cam 131b.

[0059] The operation of the cam clutch 100 according to the first embodiment described above will be explained below.

[0060] First, when the cam attitude changing part 141 is not in contact with the engaging part 136 and the cam 131 is in a position where the attitude of the cam 131 is unrestricted, it is in a locked state that prohibits relative rotation of the outer ring 120 relative to the inner ring 110 in both the forward and reverse directions. That is, the cam clutch 100 functions as a two-way clutch.

[0061] When the main body 142 is moved toward the cam 131 by manual means or by a suitable drive source, the cam attitude change part 141 engages with the engagement part 136 and restricts the attitude of both cams 131a and b. As a state in which cams 131a and b do not simultaneously contact the inner ring 110 and the outer ring 120, the cam clutch 100 can function as an idle state that allows relative rotational movements in two directions.

[0062] Although cams 131a and 131b are cams in opposite directions, they can also be configured such that the one-way clutch state and the idle state can be switched by using only either cam 131a or 131b.

[0063] Alternatively, the locking state and the one-way clutch state can be switched by providing the engaging part 136 only on either of the cams 131a and b, and by using the movement of the body part 142 to make the cam attitude changing part 141 engage with the engaging part 136 on either side only.

[0064] And, as Figure 7 As shown, it can also be configured such that the groove of the cam attitude changing part 141 is deepened, and the engaging part 136 of one of the cams 131a and b is lengthened and can slide axially within the groove of the cam attitude changing part 141. By forming a state that engages only with the longer engaging part 136 of the cams 131a and b at the intermediate position of the axial movement of the cam attitude changing part 141, the three states of locked state, one-way clutch state and freewheeling state can be switched.

[0065] Example 2

[0066] Figure 8 This is a cross-sectional view of the plane including the central shaft of the cam clutch configuration according to the second embodiment of the present invention.

[0067] The cam clutch 200 has a cam mechanism with the same configuration as the cam clutch 100 in the first embodiment arranged side by side in the axial direction, and shares the body part 242 of the operation mode switching mechanism 240 on the central side.

[0068] The action mode switching mechanism 240 includes: a ring-shaped body 242, which is configured to rotate relative to the inner ring 210 and two outer rings 220; and a cam attitude changing part 241, which is circumferentially arranged on both sides of the body 242 in correspondence with the cams 231 on both sides.

[0069] On the cam clutch 200, the operation mode switching mechanism 240 is set to switch between three positions: a position in which neither of the two cam attitude changing parts 241 engages with the engagement part 236 of the two cams 231; a position in which one cam attitude changing part 241 engages with the engagement part 236; and a position in which the other cam attitude changing part 241 engages with the engagement part 236.

[0070] Thus, by manually or by driving the main body 242 axially, it is possible to switch to three operating states: a neutral position in which the clutch mechanisms on both sides are locked; an idling state in which only one side is allowed to rotate relative to the other side while the other side is locked; and the opposite of the other operating states.

[0071] Alternatively, the neutral position can be omitted to switch between the two action states.

[0072] Furthermore, the cam mechanisms on both sides of the action mode switching mechanism 240 can each have any of the switching functions exemplified in the first embodiment, or different switching functions can be appropriately combined.

[0073] For example, having on both sides Figure 7 When using the cam mechanism shown, it can switch between 5 action states.

[0074] In addition, the shape and structure of the main body 242 can be changed so that the cam attitude changing parts 241 on both sides can move axially independently, and the cam attitude changing parts 241 can be engaged with the engaging parts 236 simultaneously through the clutch mechanisms on both sides.

[0075] Example 3

[0076] Figure 9 This is a cross-sectional view of the plane including the central shaft of the cam clutch configuration according to the third embodiment of the present invention.

[0077] The cam clutch 300 is a double-layer structure with the same cam mechanism as the cam clutch 100 according to the first embodiment. An inner clutch mechanism is arranged between the inner ring 310 and the middle ring 350, and an outer clutch mechanism is arranged between the middle ring 350 and the outer ring 320.

[0078] The middle ring 350 is equivalent to the outer ring on the inner clutch mechanism and the inner ring on the outer clutch mechanism.

[0079] The action mode switching mechanism 340 includes: a ring-shaped body 342, which is configured to rotate relative to the inner ring 310, the middle ring 350 and the outer ring 320; and a double-layer cam attitude change part 341, which corresponds to the inner and outer cams 331 and is configured to be circumferential on the side of the cam 331 of the body 342.

[0080] In this cam clutch 300, the relationship between the inner and outer cam attitude change part 341 of the operation mode switching mechanism 340 and the engagement part 336 of the inner and outer cams 331 is the same as that of the cam clutch 100 in the first embodiment.

[0081] The double-cam mechanism can have any of the switching functions illustrated in the first embodiment, as long as different cams are appropriately combined.

[0082] In addition, multiple states corresponding to the axial movement position can be switched by appropriately combining the depth of the groove of the inner and outer cam attitude change part 341 and the length of the engagement part 336 of each inner and outer cam 331.

[0083] Furthermore, the shape or structure of the main body 342 can be changed so that the inner and outer cam attitude changing parts 341 can move axially independently and the state of the inner and outer cam mechanisms can be controlled independently.

[0084] While the embodiments of the present invention have been described in detail above, the present invention is limited to the embodiments described above. Various design changes can be made without departing from the scope of the present invention as described in the design scheme.

Claims

1. A cam clutch comprising: at least one set of inner and outer rings configured to rotate relative to each other on the same axis; a plurality of cams disposed circumferentially between the inner and outer rings; and a force-applying unit for applying force to the plurality of cams in a radial direction, characterized in that, It has a mechanism for switching between any two or more operating modes, namely: an idling state that allows relative rotational movement of the outer and inner rings in two directions; a one-way clutch state that allows relative rotational movement of the outer and inner rings in either forward or reverse direction; and a locked state that prohibits relative rotational movement of the outer and inner rings in two directions. The motion mode switching mechanism includes a cam attitude changing part that can move axially independently of the rotation of the inner and outer rings. A portion or all of the plurality of cams has an engaging portion that protrudes from the side toward the cam attitude changing part. The cam attitude change part is formed into a circumferential groove for the engaging part to fit into, and is configured to slide with the engaging part, and restrict the radial position of the engaging part in two directions.

2. The cam clutch according to claim 1, characterized in that, The plurality of cams includes: a first cam that tilts when the outer ring or the inner ring rotates in one direction to frictionally engage with the outer ring and the inner ring; and a second cam that tilts when the outer ring or the inner ring rotates in the other direction to frictionally engage with the outer ring and the inner ring.

3. The cam clutch according to claim 2, characterized in that, The action mode switching mechanism is clamped by at least two sets of outer rings and inner rings on both sides of the axial direction.

4. The cam clutch according to claim 3, characterized in that, The first cam is disposed on the side of one of the action mode switching mechanisms, between the outer ring and the inner ring. The second cam is positioned between the outer ring and the inner ring on the side of the other side of the motion mode switching mechanism.

5. The cam clutch according to claim 3, characterized in that, The first cam and the second cam are configured on the same circumference.

6. The cam clutch according to claim 5, characterized in that, The first cam and the second cam are arranged in an alternating manner.

7. The cam clutch according to any one of claims 2 to 6, characterized in that, At least two sets of the outer ring and the inner ring are arranged in two layers with different diameters on the same circumference.

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