Cam clutch

Abstract

The present invention aims to provide a cam clutch that enables smooth switching between operating modes while preventing the occurrence of cam seizure, and achieves noise reduction and long service life with a simple structure without increasing the size and number of components. The above problem is solved by providing a transmission member (161) which comes into contact with a first cam (131a) and a second cam (131b) each having different engagement directions to be rotatable and movable in the axial direction, with its rotation center being fixed by a cage (140), and by forming the transmission member (161) such that the transmission member (161) can tilt the first cam (131a) when rotated and tilt the second cam (131b) when moved in the axial direction.

Description

Technical area

[0001] The present invention relates to a cam clutch configured to be capable of switching between operating modes, for example, a bidirectional engagement mode in which torque transmission is possible in both the forward and reverse directions between an outer ring and an inner ring, a unidirectional engagement mode in which torque transmission is possible in the forward or reverse directions between the outer ring and the inner ring, and a bidirectional idle mode in which the drive-side rotating ring composed of the outer ring and the inner ring idles in both the forward and reverse directions, thereby interrupting torque transmission between the outer ring and the inner ring. Current state of the art

[0002] Bidirectional clutches are known as clutches for controlling torque transmission and de-energization, and can switch between drive and idle in both forward and reverse directions.

[0003] For example, Patent Literature 1 describes a clutch configured to control a holder that holds both a first clamping piece and a second clamping piece that are biased by a biasing means so that their rotation-locking directions are opposite to each other, thereby enabling switching between operation modes, that is, a unidirectional engagement mode in which torque transmission is possible only in the forward direction between an outer ring and an inner ring, and a unidirectional engagement mode in which torque transmission is possible only in the reverse direction between the outer ring and the inner ring. List of citationsPatent literature

[0004] Patent Literature 1: Japanese Patent Application Laid-Open No. 2011-231828 Overview of the inventionTechnical problem

[0005] Therefore, clutches that have symmetrically arranged sprags that engage in only one direction of rotation and that are designed to tilt both sprags, allowing switching between operating modes, are generally likely to experience "seizing," in which all cams engage simultaneously. In other words, in such clutches, a sprag tilts to engage both an outer ring and an inner ring immediately when torque is applied to either the outer ring or the inner ring.

[0006] When the torque is removed, one sprag tilts in the disengagement direction and enters a neutral state. During this time, however, the other sprag tilts in the engagement direction and begins to engage the outer race and inner race before one sprag has disengaged. As a result, a "seizing" condition, in which all cams engage simultaneously, is likely to occur.

[0007] In such a condition, all sprags engage with high surface pressure. Therefore, when switching the operating modes of the couplings, a large force is required to change the position of the sprags, which can damage the sprag engagement surfaces on the outer ring and inner ring, or the raceway surfaces of the outer ring and inner ring. This can shorten the service life of the couplings.

[0008] To solve this problem, in the bidirectional coupling described above, the first and second clamping pieces are arranged side by side in the common holder so that their lockings are opposite to each other, and it is configured to hold the first and second clamping pieces in a preloaded state, the first clamping piece being preloaded in the anti-lock direction and the second clamping piece being preloaded in the locking direction, thereby preventing the occurrence of the seizure.

[0009] However, the bidirectional clutch described above is designed to control the retainer during switching between operating modes, forcibly tilting all of the first and second sprags at once. Therefore, the bidirectional clutch described above cannot realize a bidirectional engagement mode in which torque transmission is possible in both the forward and reverse directions between the outer ring and the inner ring, and a bidirectional idle mode in which the drive-side rotating ring composed of the outer ring and the inner ring idles in both the forward and reverse directions, thereby interrupting torque transmission between the outer ring and the inner ring. In addition, since slip torque occurs when one of the first and second sprags comes into contact with the inner ring and the outer ring during idle operation, the idle torque increases.Furthermore, due to a design in which the holder is controlled by applying a load from a load application unit to the holder via a gear transmission, the torque during idle operation increases because the gears connected to the holder act as a rotational resistance.

[0010] The present invention has been made in view of the above circumstances and aims to provide a cam clutch that enables smooth switching between operating modes while preventing the occurrence of cam seizure, and achieves noise reduction and long life with a simple structure without increasing the size and number of components. Solution to the problem

[0011] To solve the above problem, the present invention provides a cam clutch comprising: an outer ring and an inner ring provided so as to be rotatable relative to each other on the same axis; a plurality of cams arranged between the outer ring and the inner ring; and a cage that holds the plurality of cams in a circumferential direction, wherein the plurality of cams includes a first cam and a second cam that have different engagement directions relative to the outer ring and the inner ring and are arranged so that the first cam and the second cam form a pair; wherein a transmission member is provided that comes into contact with each of the paired first and second cams and is provided so as to be rotatable and movable in an axial direction, a rotation center thereof being fixed by the cage; and wherein the transmission member is configured to be capable ofto tilt the first cam between a ready-to-engage state and a state in which the first cam is not in contact with the outer ring or the inner ring when it is rotated, and is configured to be able to tilt the second cam between a ready-to-engage state and a state in which the second cam is not in contact with the outer ring or the inner ring when it is moved in the axial direction. Advantageous effects of the invention

[0012] According to the invention of claim 1, the rocking of the first cam and the second cam is performed independently of each other through the various operations of the transmission member. Thereby, the operation mode of the cam clutch can be configured to be switchable between three operation modes, namely, a bidirectional engagement mode, a unidirectional engagement mode, and a bidirectional idle mode, with a simple configuration. Moreover, during switching of the operation mode between the bidirectional engagement mode and the bidirectional idle mode, the rocking of the first cam and the second cam is performed stepwise, thereby reducing the number of cams rotated at the same time. As a result, since the torque required to disengage the cams during the application of torque can be reduced, smooth operation can be achieved.In addition, the engagement surfaces of the cams and the raceway surfaces of the outer ring and inner ring are less susceptible to damage, thus achieving a long service life. Furthermore, the tilting of the first cam is achieved by the rotation of the transmission element, while only the tilting of the second cam is achieved by the axial movement of the transmission element. Therefore, compared to a design in which the tilting of the cams is achieved only by the axial movement of the operating mode switching device, the axial movement range of the transmission element can be reduced, thereby preventing an increase in the axial dimension.

[0013] In addition, when the operating mode is set to bidirectional idle mode, all cams are not in contact with the outer ring or inner ring, preventing slippage during idle operation. In this regard, the cam engagement surfaces and the raceway surfaces of the outer ring and inner ring are less susceptible to damage, thus achieving a long service life and reducing noise.

[0014] According to the invention of claim 2, in conjunction with the first cam tilting to engage the outer ring and the inner ring when a torque is applied to the outer ring or the inner ring, the second cam, which would normally remain in the engagement-ready state, is caused to tilt in a disengagement direction, while the engagement surface of the second cam is caused to separate from the raceway surface of the outer ring and / or the raceway surface of the inner ring. This can prevent the second cam from engaging the outer ring and the inner ring before the first cam disengages, even if the second cam tilts in the engagement direction when the torque is released. This can achieve smooth operation, enabling high responsiveness.In addition, suppressing the attack eliminates the need for a large drive source for moving the transmission element in the axial direction, enabling energy savings and downsizing.

[0015] According to the invention of claim 3, no separate driving force is required for rotating the transmission member, and both the rotation and the axial movement of the transmission member can be achieved by simply moving the selector in the axial direction, whereby it is possible to avoid the complexity and enlargement of the structure of the cam clutch.

[0016] According to the invention of claim 4, the transmission element can have functions for tilting the first cam and the second cam. As a result, other components contributing to switching the operating mode can have a simple structure. Therefore, the structure can be simplified, facilitating manufacturing.

[0017] According to the invention of claim 5, the mechanism for rotating and axially moving the transmission element does not act as a rotational resistance, thereby enabling a reduction of the torque during idle operation.

[0018] According to the invention of claim 6, the size of the cam clutch in the axial direction can be reduced, and the same biasing means can be used for all the cams, thereby enabling a reduction in the number of components and facilitating the simplification of the structure. Brief description of the drawings [ Fig. 1] Fig. 1 is an exploded perspective view showing a configuration in an example of the cam clutch of the present invention. [ Fig. 2] Fig. Figure 2 shows a cross-sectional view obtained by cutting along a plane parallel to the axis of rotation and showing part of the Fig. 1 shows the cam clutch. [ Fig. 3] Fig. 3 shows a cross-sectional view of the Fig. 1, which is obtained by cutting along a plane perpendicular to the axis of rotation. [ Fig. 4] Fig. Figure 4 shows the configuration of a first cam, wherein (a) is a perspective view and (b) is an end view of an end face. [ Fig. 5] Fig. Figure 5 shows the configuration of a second cam, where (a) is an end view of an end face and (b) is a perspective view. [ Fig. 6] Fig. 6 is a perspective cross-sectional view of a portion of a cage. [ Fig. 7] Fig. 7 shows a side view of the design of a transmission element. [ Fig. 8] Fig. 8 shows the design of the Fig. 7, wherein (a) is an end view of one end side and (b) is an end view of the other end side. [ Fig. 9] Fig. 9 shows a plan view of the Fig. 1 as seen from one end side in the axial direction, with a part omitted. [ Fig. 10] Fig. 10 is a side view schematically showing the state of the cam clutch when the operation mode of the Fig. 1 is set to a bidirectional engagement mode. [ Fig. 11A] Fig. 11A is a view showing the contact state between the cam contact part of the transmission member and the step parts of the cams when the first cam and the second cam are in an engagement standby state under the bidirectional engagement mode. [ Fig. 11B] Fig. 11B is a view schematically showing the positional relationship between the cams and the transmission member viewed from one end side in the axial direction when the first cam and the second cam are in the engagement standby state under the bidirectional engagement mode. [ Fig. 12] Fig. 12 is a side view schematically showing the state of the cam clutch when the operation mode of the Fig. 1 is set to a unidirectional engagement mode. [ Fig. 13A] Fig. 13A is a view schematically showing the positional relationship between the cams and the transmission member viewed from one end side in the axial direction when the second cam is in the engagement standby state under the unidirectional engagement mode. [ Fig. 13B] Fig. 13B is a view showing the contact state between the cam contact part of the transmission member and the step parts of the cams when the second cam is in an engagement standby state under the unidirectional engagement mode. [ Fig. 14] Fig. 14 is a side view schematically showing the state of the cam clutch when the operation mode of the Fig. 1 is set to a unidirectional engagement mode. [ Fig. 15] Fig. Fig. 15 is a view showing the contact state between the cam contact part of the transmission element and the step parts of the cams when the operation mode of the Fig. 1 is set to the bidirectional idle mode. Description of embodiments

[0019] As in Fig. 1, a cam clutch 100 of the present invention includes an outer ring 110, an inner ring 120, a cam mechanism 130, and an operating mode switching mechanism 160.

[0020] As in the Fig. 2 and Fig. 3, the outer ring 110 and the inner ring 120 are provided in the assembled state of the cam clutch 100 so as to be rotatable relative to one another on the same axis of rotation X and are designed such that a raceway surface 111 of the outer ring 110 and a raceway surface 121 of the inner ring 120 face one another.

[0021] As in Fig. 1, the cam mechanism 130 includes a plurality of cams 131, a cage 140 that holds the plurality of cams 131 at intervals in the circumferential direction, and a biasing means 150 that biases each of the plurality of cams 131 in the engagement direction to contact the outer ring 110 and the inner ring 120.

[0022] As in Fig. As shown in Figure 3, each of the plurality of cams 131 includes a first cam 131a and a second cam 131b that have different engagement directions relative to the outer ring 110 and the inner ring 120, the first cam 131a and the second cam 131b forming a pair. A plurality of cam pairs 132 are arranged at predetermined intervals in the circumferential direction on the same circumference. Hereinafter, the first cam 131a and the second cam 131b are simply referred to as cam 131 unless otherwise noted.

[0023] The arrangement of the plurality of cams 131 on the same circumference can reduce the size of the cam clutch 100 in the axial direction and enables the same biasing means 150 to be used for all the cams 131, thereby enabling a reduction in the number of components and facilitating the simplification of the structure.

[0024] In this embodiment, 10 sets of cam pairs 132 are arranged at equal intervals in the circumferential direction. However, the number of cam pairs 132 is not particularly limited and can be adjusted accordingly depending on the target torque capacity. Furthermore, the intervals between the cam pairs 132 may be uneven.

[0025] As in the Fig. 4(a) and Fig. As shown in Figure 4(b), the first cam 131a has an outer ring-side engagement surface 133 having an arcuate portion and formed in a curved shape, and an inner ring-side engagement surface 134 having a larger radius of curvature than the outer ring-side engagement surface 133 and formed in an arcuate shape. The first cam 131a is configured to engage the outer ring 110 and the inner ring 120 when the outer ring 110 rotates in the forward direction (in Fig. 3 counterclockwise) or when the inner ring 120 is rotated in the reverse direction (in Fig. 3 clockwise).

[0026] In this embodiment, for example, an annular coil spring is used as the biasing means 150, and a coil spring fitting groove 135 extending in the circumferential direction is formed on the outer ring-side engagement surface 133 of the first cam 131a. The coil spring fitting groove 135 is formed such that, when fitting the coil spring, a counterclockwise torque as shown in Fig. 3, is exerted on the first cam 131a.

[0027] In addition, the first cam 131a has a step part 136 on one end surface in the axial direction which extends outward in the axial direction.

[0028] In this embodiment, the step part 136 is formed to form a flat shape obtained by cutting out the outer ring-side portion at one end of the first cam 131a using two planes that intersect so that the vertex angle becomes obtuse and that are perpendicular to the cam end surface. The vertex of the step part 136 is located on the outer ring-side engaging surface 133 side relative to a center of curvature C1 of the inner ring-side engaging surface 134 and is formed at a position facing the side (right side in Fig. 4(b)) at which the paired second cam 131b is positioned, relative to a normal H at a contact P between the first cam 131a and the raceway surface 121 of the inner ring 120.

[0029] The second cam 131b is configured to engage the outer ring 110 and the inner ring 120 when the outer ring 110 is rotated in the reverse direction or when the inner ring 120 is rotated in the forward direction.

[0030] As in the Fig. 5(a) and Fig. As shown in Fig. 5(b), the second cam 131b according to this embodiment has the same configuration as the first cam 131a and is formed to form a pair with the first cam 131a in an opposing arrangement. In other words, the second cam 131b has an outer peripheral contour shape obtained by inverting the first cam 131a, and the apex of a step part 136 is located on the outer ring-side engaging surface 133 side relative to a center of curvature C2 of the inner ring-side engaging surface 134 and is formed at a position facing the side (left side in Fig. 5(a)) at which the paired first cam 131a is positioned, relative to a normal H at a contact P between the second cam 131b and the raceway surface 121 of the inner ring 120.

[0031] A hose spring fitting groove 135 is designed so that when fitting the hose spring a torque in the clockwise direction, as in Fig. 3, is exerted on the second cam 131b.

[0032] As in Fig. 6, the cage 140 has a small-diameter cylindrical part 141, a collar part 145 formed to project outward in the radial direction along the entire circumferential direction at one end in the axial direction of the small-diameter cylindrical part 141, and a large-diameter cylindrical part 147 formed on an axial end surface of the collar part 145 so that its inner peripheral surface is continuous with that of the small-diameter cylindrical part 141.

[0033] Openings 142 are provided in the small-diameter cylindrical portion 141 at equal intervals in the circumferential direction. Each opening 142 is circumferentially divided by an axially extending columnar portion 143, with the space on the forward rotation side being formed as the first cam holding portion 144a and the space on the reverse rotation side being formed as the second cam holding portion 144b. The circumferential dimensions of the first cam holding portion 144a and the second cam holding portion 144b are designed to be smaller than the maximum outer diameter of the cam 131.

[0034] On the outer peripheral surface of the large-diameter cylindrical portion 147, a transmission element receiving portion 148 is formed, which is a columnar space open to the outside in the radial direction. The transmission element receiving portion 148 is formed by forming a through hole 146 extending in the axial direction at a circumferential position corresponding to the column portion 143 of each opening 142 in the collar portion 145.

[0035] The first cam 131a and the second cam 131b are inserted from the radially outer side into the corresponding first cam holding part 144a and the second cam holding part 144b and arranged so that the inner ring side engagement surfaces 134 protrude radially inward from the inner peripheral surface of the cage 140 and are held by the cage 140 when the coil spring is installed.

[0036] The cam mechanism 130 is arranged such that the small-diameter cylindrical part 141 of the cage 140 is inserted into the annular space between the raceway surface 111 of the outer ring 110 and the raceway surface 121 of the inner ring 120. Thus, the plurality of cams 131 are arranged in the annular space, and the cage 140 is provided to be rotatable independently of the outer ring 110 and the inner ring 120. By providing the cage 140 to be rotatable independently of the outer ring 110 and the inner ring 120, the idle torque can be reduced.

[0037] Therefore, the cam clutch 100 according to this embodiment includes an operation mode switching mechanism 160 that switches between three operation modes: a bidirectional engagement mode in which torque transmission is possible in both the forward and reverse directions between the outer ring 110 and the inner ring 120; a unidirectional engagement mode in which torque transmission is possible in either the forward or reverse direction between the outer ring 110 and the inner ring 120; and a bidirectional idle mode in which the drive-side rotating ring composed of the outer ring 110 and the inner ring 120 idles in both the forward and reverse directions, thereby interrupting torque transmission between the outer ring 110 and the inner ring 120.

[0038] As in the Fig. 1 to 3, the operation mode switching mechanism 160 includes a plurality of transmission members 161 provided corresponding to each of the plurality of cam pairs 132 and configured to be capable of separately tilting the paired first cam 131a and second cam 131b, and a selector 170 that moves each of the plurality of transmission members 161 simultaneously.

[0039] The transmission member 161 is configured to be capable of rocking the first cam 131a between an engagement standby state and a state in which the first cam 131a is not in contact with the outer ring 110 or the inner ring 120 when rotated about an axis extending along the rotation axis X of the cam clutch 100, and is also configured to be capable of rocking the second cam 131b between an engagement standby state and a state in which the second cam 131b is not in contact with the outer ring 110 or the inner ring 120 when moved in the axial direction.

[0040] As in Fig. 7, the transmission member 161 according to this embodiment has a columnar base member part 162, a load application part 163 formed to extend axially outward at one axial end of the base member part 162, and a cam contact part 166 formed to extend axially outward at the other axial end of the base member part 162.

[0041] As in Fig. 8(a), the load application part 163 is formed to have a substantially semicircular columnar shape in cross section and has a flat rotational force acting surface 164 arranged, for example, in a plane perpendicular to one end surface of the base member part 162 including a central axis O, and a guide surface 165 which is continuous with the rotational force acting surface 164 and extends so as to be tilted toward the one axial end on its outer peripheral surface side.

[0042] As in Fig. 8(b), the cam contact part 166 is formed to have a substantially semicircular columnar shape in cross section at a position on the side opposite to the load application part 163 across the central axis in plan view, and has a flat cam pressure surface 167 positioned, for example, on a plane perpendicular to the other end surface of the base member part 162 including the central axis O and tilted in the rotational direction relative to the rotational force acting surface 164, and a cam acting surface 168 connected to an axial end of the cam pressure surface 167 and used for tilting the cams 131. The cam action surface 168 is formed to be tilted to separate from the cam pressure surface 167 toward one axial end, and an end edge 168a extends along the tilting direction of the rotational force action surface 164 relative to the cam pressure surface 167.

[0043] With the above configuration, the transmission member 161 is capable of having functions for tilting the first cam 131a and the second cam 131b, and other components contributing to switching between the operating modes of the cam clutch 100 can have a simple structure. Therefore, the structure can be simplified, facilitating manufacturing.

[0044] The transmission element 161 is received in the transmission element receiving part 148, with the base element part 162 inserted into the through hole 146 in the cage 140, and is provided to be rotatable and movable in the axial direction with the rotation center fixed by the cage 140.

[0045] The transmission member 161 is configured such that when the operating mode of the cam clutch 100 is set to the bidirectional engagement mode, that is, when both the first cam 131a and the second cam 131b are in the engagement standby state, the cam pressure surface 167 of the cam contact part 166 is in contact with the step part 136 of both the paired first cam 131a and the paired second cam 131b, and such that the transmission member 161 is rotated in response to the tilting of the first cam 131a in the engagement direction, thereby tilting the second cam 131b in the disengagement direction. Therefore, in conjunction with the first cam 131a tilting to engage the outer ring 110 and the inner ring 120, when a torque is applied to the outer ring 110 or the inner ring 120, the second cam 131b, which would normally remain in the engagement standby state, is tilted in the disengagement direction.This allows the outer-ring-side engagement surface 133 of the second cam 131b to be separated from the raceway surface 111 of the outer ring 110, thereby preventing the second cam 131b from engaging the outer ring 110 and the inner ring 120 before the first cam 131a disengages, even if the second cam 131b tilts in the engagement direction when the torque is released. This allows for smooth operation, enabling high responsiveness. Furthermore, by suppressing engagement, the need for a large drive source for moving the transmission member 161 in the axial direction is eliminated, enabling energy savings and downsizing.

[0046] The selector 170 according to this embodiment is formed, for example, as an annular member and fitted externally to the large-diameter cylindrical part 147 of the cage 140 so as to be movable in the axial direction.

[0047] In the cam clutch 100, when both the first cam 131a and the second cam 131b are in the engagement standby state, the transmission element 161 is formed such that a part of the load application part 163 projects outward in the radial direction from the opening edge of the transmission element receiving part 148, as shown in Fig. 9. Accordingly, the selector 170 is configured to rotate the transmission element 161 by engaging the transmission element 161. This configuration eliminates the need for a separate drive force to rotate the transmission element 161. By simply moving the selector 170 in the axial direction, both the rotation and the axial movement of the transmission element 161 can be achieved, thereby making it possible to prevent the complexity and enlargement of the structure of the cam clutch 100.

[0048] The selector 170 is moved in the axial direction manually or by an actuator (not shown) or the like.

[0049] The operation of the above cam clutch 100 is described below.

[0050] First, as in Fig. As shown in Figure 10, when the selector 170 is fixed in a first fixed position and not in contact with the transmission member 161, the first cam 131a and the second cam 131b remain in the engagement standby state to initiate immediate engagement with the outer ring 110 and the inner ring 120 when torque is applied to the outer ring 110 or the inner ring 120. Accordingly, the operating mode of the cam clutch 100 is set to the bidirectional engagement mode, in which torque transmission is possible in both the forward and reverse directions between the outer ring 110 and the inner ring 120.

[0051] When the first cam 131a and the second cam 131b are in the engagement standby state, the cam pressure surface 167 of the cam contact part 166 in the transmission element 161 is in contact with both the step part 136 of the first cam 131a and the step part 136 of the second cam 131b, as shown in Fig. 11A. Thus, when the first cam 131a rotates to tilt in the engagement direction upon application of torque, the transmission member 161 rotates in response to the tilting of the first cam 131a. As a result, the second cam 131b rotates to tilt in the disengagement direction, and the outer gear-side engagement surface 133 of the second cam 131b separates from the raceway surface 111 of the outer ring 110. When the torque is removed, the first cam 131a rotates to tilt in the disengagement direction and enters the engagement standby state. At this time, the second cam 131b rotates to tilt in the engagement direction.However, since the outer ring-side engagement surface 133 of the second cam 131b has already been separated from the raceway surface 111 of the outer ring 110 during the engagement of the first cam 131a, the second cam 131b can be prevented from engaging the outer ring 110 and the inner ring 120 before the disengagement of the first cam 131a.

[0052] The same also applies when the second cam 131b rotates to tilt in the engagement direction. In response to the tilting of the second cam 131b, the transmission member 161 rotates, causing the first cam 131a to rotate and tilt in the disengagement direction. This causes the outer-ring-side engagement surface 133 of the first cam 131a to separate from the raceway surface 111 of the outer ring 110. When the torque is removed and the second cam 131b rotates to tilt in the disengagement direction and enters the engagement standby state, the first cam 131a can be prevented from engaging the outer ring 110 and the inner ring 120 before the second cam 131b is disengaged.

[0053] As described above, the respective rotations of the first cam 131a and the second cam 131b are coordinated by the transmission member 161, thereby enabling smooth operation without the occurrence of seizure.

[0054] When the operating mode of the cam clutch 100 is set to the bidirectional engagement mode and the first cam 131a and the second cam 131b are in the engagement standby state, the rotational force acting surface 164 of the load application section 163 in the transmission element 161 tilts in the rotational direction relative to the cam pressure surface 167, as shown in Fig. 11B, a portion of which projects outward in the radial direction from the opening edge of the transmission element receiving part 148 (see Fig. 9).

[0055] When the selector 170 is moved toward the other axial end and the selector 170 is in a second fixed position as shown in Fig. 12, the selector 170 engages the transmission element 161, whereby the transmission element 161 is rotated, as shown in Fig. 13A. As a result, as shown in Fig. 13B, the step portion 136 of the first cam 131a is pressed by the cam pressure surface 167 of the cam contact portion 166 in the transmission member 161, and the first cam 131a is rotated to tilt in the disengagement direction. Consequently, the outer-ring-side engagement surface 133 of the first cam 131a is kept separate from the raceway surface 111 of the outer ring 110, and the operation mode of the cam clutch 100 is switched to the unidirectional engagement mode. In the unidirectional engagement mode according to this embodiment, when the inner ring 120 is rotated in the forward direction, for example, the second cam 131b engages the outer ring 110 and the inner ring 120, thereby enabling torque transmission.

[0056] In addition, in the cam clutch 100, when the selector 170 is moved from the second fixed position to the other axial end and fixed in a third fixed position as shown in Fig. 14, the transmission element 161 is pressed by the selector 170 and moved in the axial direction as shown in Fig.15. Due to the action of the cam action surface 168 in the cam contact part 166, the second cam 131b is rotated to tilt in the disengagement direction. Consequently, the outer ring-side engagement surface 133 of the second cam 131b is kept separate from the raceway surface 111 of the outer ring 110. As with the first cam 131a, the outer ring-side engagement surface 133 is kept separate from the raceway surface 111 of the outer ring 110. Consequently, the drive-side rotary ring rotates idly even when rotated in either the forward or reverse direction, and the operation mode of the cam clutch 100 is switched to the bidirectional idling mode in which the torque transmission between the outer ring 110 and the inner ring 120 is interrupted.

[0057] Therefore, according to the above-described cam clutch 100, the rocking of the first cam 131a and the second cam 131b is performed independently of each other through the various operations of the transmission member 161. Therefore, the operation mode of the cam clutch 100 can be configured to switch between the three operation modes, namely, the bidirectional engagement mode, the unidirectional engagement mode, and the bidirectional idle mode, with a simple configuration.

[0058] Furthermore, during switching of the operation mode between the bidirectional engagement mode and the bidirectional idle mode, the rocking of the first cam 131a and the second cam 131b is performed gradually, thereby reducing the number of cams 131 rotating at the same time. Since the torque required to disengage the cams 131 during torque application can be reduced, smooth operation can be achieved. Furthermore, the outer ring-side engagement surface 133 and the inner ring-side engagement surface 134 of the cams 131, as well as the raceway surfaces 111 and 121 of the outer ring 110 and the inner ring 120, are less likely to be damaged, thereby achieving a long service life.

[0059] Furthermore, the tilting of the first cam 131a is achieved by the rotation of the transmission member 161, while only the tilting of the second cam 131b is achieved by the axial movement of the transmission member 161. Therefore, compared with a configuration in which the tilting of the cams 131 is achieved only by the axial movement of the operation mode switching device, the axial movement range of the transmission member 161 can be reduced, thereby preventing an increase in the axial dimension.

[0060] In addition, when the operating mode is set to the bidirectional idle mode, all cams 131 are not in contact with the outer ring 110 or the inner ring 120, thereby preventing the occurrence of slip torque during idle operation. Also in this regard, the outer ring-side engagement surface 133 and the inner ring-side engagement surface 134 of the cams 131, as well as the raceway surfaces 111 and 121 of the outer ring 110 and the inner ring 120, are less likely to be damaged, thereby achieving a long service life and reducing noise.

[0061] The above-described embodiment describes the present invention in detail. However, the present invention is not limited to the above embodiment, and various design changes are possible without departing from the invention described in the claims.

[0062] In the above embodiment, for example, the transmission member is configured with the load application member in which the rotational force acting surface is configured to tilt in the rotational direction relative to the pressing surface and is configured to protrude from the opening edge of the transmission member receiving part when the cam pressing surface is in contact with both the first cam and the second cam. This configuration enables rotation of the transmission member through the engagement of the selector formed as an annular member. However, the selector may be configured with a tiltable surface part that rotates the transmission member when it is moved in the axial direction.

[0063] Furthermore, in the above embodiment, the rotational force acting surface and the cam pressure surface in the transmission element are formed as flat surfaces. However, they do not need to be flat.

[0064] Furthermore, the cams are designed such that the stepped portion contacts the cam contact portion of the transmission element at one axial end. However, the cams may be formed, for example, with a pin element or the like to absorb a load from the transmission element.

[0065] Furthermore, in the above embodiment, the cam positioned on the forward rotation side of the cam pair is defined as the first cam, and the cam pressure surface of the transmission member is configured to tilt relative to the rotational force acting surface so that the cam on the forward rotation side is rotated in response to the rotation of the transmission member. The cam positioned on the reverse rotation side of the cam pair may be defined as the first cam, and the cam pressure surface may be configured to tilt relative to the rotational force acting surface so that the cam on the reverse rotation side is rotated in response to the rotation of the transmission member.Under this configuration, when the outer ring is rotated in the forward direction or the inner ring is rotated in the reverse direction, the cam positioned on the forward rotation side of the cam pair engages the outer ring and the inner ring, thereby enabling torque transmission in the opposite direction compared to the above configuration.

[0066] Furthermore, in the above embodiment, the cams are configured to be tilted to separate from the outer ring. However, in the cam clutch according to the present invention, the cams may be configured to be tilted to separate from the inner ring.

[0067] Furthermore, in the above embodiment, the preloading means is described as being provided. However, the configuration may also be such that no preloading means is provided. Furthermore, the preloading means is not limited to a coil spring, but may also be formed by elastic elements such as a plurality of disc springs or torsion springs. List of reference symbols 100 cam clutch 110 Outer ring 111 running track area 120 inner ring 121 running track area 130 Cam mechanism 131 cams 131a first cam 131b second cam 132 cam pair 133 outer ring side contact surface 134 inner ring side contact surface 135 Hose spring fitting groove 136 step part 140 cage 141 cylindrical part with small diameter 142 Opening 143 Column part 144a first cam holding part 144b second cam holding part 145 collar part 146 through hole 147 cylindrical part with large diameter 148 Transmission element receiving part 150 preloading devices 160 Operating mode switching mechanism 161 transmission element 162 Base element part 163 Load application part 164 Torque acting area 165 guide surface 166 Cam contact part 167 Cam pressure surface 168 Cam action area 168a an end edge 170 Selector QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2011-231828

[0004]

Claims

[1] A cam clutch comprising: an outer ring and an inner ring provided to be rotatable relative to each other on the same axis; a plurality of cams disposed between the outer ring and the inner ring; and a cage holding the plurality of cams in a circumferential direction, wherein the plurality of cams comprise a first cam and a second cam having different engagement directions with respect to the outer ring and the inner ring and arranged so that the first cam and the second cam can form a pair, wherein a transmission member is provided which comes into contact with each of the paired first and second cams and is provided so as to be rotatable and movable in an axial direction, a rotation center thereof being fixed by the cage, and wherein the transmission member is configured to be capable of tilting the first cam between an engagement standby state and a state in which the first cam is not in contact with the outer ring or the inner ring when rotated, and is configured to be capable of tilting the second cam between an engagement standby state and a state in which the second cam is not in contact with the outer ring or the inner ring when moved in the axial direction. [2] A cam clutch according to claim 1, wherein, when the first cam and the second cam are each in the engagement ready state, the transmission member is configured to be rotated in response to the tilting of the first cam in the engagement direction, thereby tilting the second cam in a disengagement direction. [3] A cam clutch according to claim 1, comprising: a selector provided to be movable in the axial direction relative to the cage and used to move the transmission member, the selector being configured to rotate the transmission member by engaging the transmission member. [4] A cam clutch according to claim 1, wherein the transmission member comprises a columnar base member part, a load application member provided at one axial end of the base member part, and a cam contact part provided at the other axial end of the base member part, wherein the load application part has a rotational force application surface, and wherein the cam contact part has a cam pressure surface that tilts in a rotational direction relative to the rotational force acting surface, and a cam acting surface that tilts the cam, the cam acting surface tilting to separate from the cam pressure surface toward the one axial end, and is formed such that an end edge extends along a tilting direction of the rotational force acting surface relative to the cam pressure surface. [5] A cam clutch according to claim 1, wherein the cage is provided to be rotatable independently of the outer ring and the inner ring. [6] A cam clutch according to claim 1, wherein the first cam and the second cam are arranged on the same circumference, and further comprising biasing means for biasing the first cam and the second cam into an engagement ready state.

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