Selectable clutch

Abstract

This invention provides a meshing clutch with a simple structure that reduces friction loss and prevents noise generation, while also enabling miniaturization, extended lifespan, and reduced load during state switching. [Solution] In a selectable clutch 100 equipped with a selector 150, a support groove 111 is formed on one of the inner ring 110 and the outer ring 120 and a pocket 112 is formed on the other, and an elastic member 150 biases a roller 130, which is positioned between the inner ring 110 and the outer ring 120, to the pocket 112, and the roller holding surface 112 of the support groove 111 and the roller holding surface 122 of the pocket 112 are formed at an inclination angle such that when the roller 130 is sandwiched, a load directed toward the pocket 125 acts on the roller 130, and in the locked state the roller 130 is held by the support groove 111, the pocket 112 and the selector 150, and the roller holding surface 151 of the selector 150 is formed as an inclined surface 151a.

Description

Technical Field

[0001] The present invention relates to a selectable clutch configured to be switchable between a free state that allows relative rotational movement of an outer ring and an inner ring in both forward and reverse directions, and a locked state that prohibits relative rotational movement of the outer ring and the inner ring in either one or both of the forward and reverse directions. Background Art

[0002] As a clutch that transmits or cuts off torque from an input shaft side to an output shaft side, for example, a ratchet-type meshing clutch that connects the input shaft side and the output shaft side by mechanical meshing is known.

[0003] As such a clutch, for example, one having a configuration including a ratchet mechanism composed of a plurality of pawl members (poles), which are torque transmission members rotatably provided on an inner peripheral portion of an outer ring, and tooth portions provided on an outer peripheral portion of an inner ring with which the pawl members mesh, is known (see, for example, Patent Documents 1 to 4, etc.). For example, in the ratchet-type clutch described in Patent Document 1, a plurality of first pawl members are urged radially inward by a spring, and a plurality of second pawl members are urged radially inward by a spring and have a circumferential direction different from that of the first pawl members. The first pawl member locks rotation of the inner ring in one direction and enables rotation of the inner ring in the other direction, and the second pawl member enables rotation of the inner ring in the one direction and locks rotation of the inner ring in the other direction. Further, an annular switching plate is disposed coaxially with the inner ring adjacent to one side of the inner ring in the central axis direction, and rotating the switching plate makes it possible to change the combination of the meshed state and non-meshed state of the first pawl member and the second pawl member with respect to the tooth portions of the inner ring.

[0004] Furthermore, as a ratchet-type clutch, there is also a known configuration in which a pocket plate and a notch plate, each having a flat clutch surface, are arranged so as to be rotatable relative to each other with their clutch surfaces facing each other, and a strut is housed in each of the multiple receiving recesses formed in the clutch surface of the pocket plate, and multiple notches (engaging recesses) are formed in the clutch surface of the notch plate (see, for example, Patent Document 5). In this ratchet-type clutch, each strut is biased toward the notch plate by a spring provided in a housing recess. When the notch plate rotates relative to the pocket plate in the engagement direction, a portion of the strut engages with the engagement recess, enabling power transmission. When the notch plate rotates relative to the pocket plate in the opposite direction to the engagement direction, the engagement between the strut and the engagement recess is released, rendering power transmission impossible. Furthermore, a select plate, which can rotate relative to the pocket plate, is positioned between the pocket plate and the notch plate. By rotating the select plate relative to the pocket plate, it is possible to switch between a state in which power can be transmitted and a state in which power cannot be transmitted. Furthermore, a selectable clutch known from Patent Document 6, etc., which has a roller placed between an inner ring and an outer ring and biased radially, is configured to switch between a free state and a locked state depending on the radial position of the roller. The roller is inserted into a pocket formed on the outer circumference of the inner ring, and the radially biased roller is held by the roller holding surface of the pocket and the roller holding surface of the selector facing the pocket to create the locked state. The free state can be achieved by rotating the selector, the inner ring and the outer ring relative to each other, moving the roller to a roller housing recess provided on the inner circumference of the selector. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-156432 [Patent Document 2] Japanese Patent Publication No. 2022-047794 [Patent Document 3] Japanese Patent Publication No. 2022-038806 [Patent Document 4] Japanese Patent Publication No. 2022-165688 [Patent Document 5] Japanese Patent Publication No. 2021-102980 [Patent Document 6] Japanese Patent Publication No. 2024-167983 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in a selectable clutch configured to allow switching between a free state and a locked state, there is a problem in that when switching from the locked state to the free state, the load acting on the torque transmission member remains until the torque decreases, making it difficult to switch to the free state. Furthermore, since torque transmission members such as claw members and struts are biased in the locking direction by springs, if the selector is driven for any reason to lock the inner ring when the inner ring is rotating relative to the outer ring in the free state, there is a risk of chipping or breakage due to impact caused by the sudden engagement. Furthermore, in a ratchet-type clutch equipped with a claw member, if the configuration involves rotating the inner ring, and the claw member is provided on the outer ring side and the engagement part on the inner ring side, the selector must be located on the inner ring side, making it difficult to access the selector from a drive source such as an actuator. On the other hand, if the claw member is provided on the inner ring side and the engagement part is provided on the outer ring side, the claw member will also rotate together with the inner ring and will be affected by centrifugal force. Furthermore, in ratchet-type clutches equipped with claw members, when configured as a two-way clutch, it is necessary to arrange the pair of claw members in opposition to each other, which tends to result in a large size and makes it difficult to handle high torque. Additionally, the claw members have a narrow surface area that receives torque and are prone to high surface pressure, raising concerns about chipping and wear due to impact. Furthermore, in a selectable clutch in which a radially biased roller is held by the roller retaining surface on the inner ring side and the roller retaining surface on the selector side, when switching from the locked state to the free state, the radially biased roller may brace against the roller retaining surface on the selector side, potentially increasing the load applied when the selector rotates relative to the inner and outer rings. Furthermore, when the selector is rotated relative to the inner and outer rings, the roller holding surface on the selector side cannot relieve the load received from the rollers, raising concerns about wear on the roller holding surface on the selector side due to the rollers.

[0007] The present invention was made based on the above circumstances, and aims to provide a selectable clutch that has a simple structure, reduces friction loss and prevents noise generation, is miniaturized and has a long lifespan, and reduces the load when switching from a locked state to a free state. [Means for solving the problem]

[0008] The present invention relates to a selectable clutch comprising a cylindrical inner ring and a cylindrical outer ring coaxially rotatable relative to each other, a plurality of rollers disposed between the inner ring and the outer ring, and an elastic member for biasing the rollers radially, wherein a pocket portion is formed on one of the outer circumferential surfaces of the inner ring and the inner circumferential surface of the outer ring, having a roller holding surface configured to accommodate the rollers and inclined with respect to the circumferential direction, and a support groove portion is formed on the other of the outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring, having a roller holding surface inclined with respect to the circumferential direction, the elastic member is provided to bias the roller toward the pocket portion, and the selector is provided to be rotatable independently of the inner ring and the outer ring, moving axially forward and backward with respect to the one of the inner ring and the outer ring in which the pocket portion is formed, the selector has a roller holding surface that contacts the roller when the roller is supported in the support groove portion, and the relative rotation of the inner ring and the outer ring is biased by moving the roller radially The device is configured to allow switching between a free state that permits rotation and a locked state that prohibits relative rotation of the inner ring and the outer ring. The roller holding surface of the pocket portion and the roller holding surface of the support groove portion are formed at an inclination angle such that when the roller is clamped, a load acts in a direction that moves the roller toward the pocket portion. In the locked state, the roller is held by the roller holding surface of the support groove portion, the roller holding surface of the pocket portion, and the roller holding surface of the selector. The selector has a roller housing recess configured to accommodate the roller when the roller is housed in the pocket portion and the selectable clutch is in a free state. The roller housing recess has a guide surface configured to move the roller radially toward the support groove portion as the selector rotates. The roller holding surface of the selector is formed as an inclined surface that becomes larger in diameter as it approaches the guide surface, thereby solving the aforementioned problem. [Effects of the Invention]

[0009] According to the invention of claim 1, in the locked state, the roller is held by the roller holding surface of the support groove, the roller holding surface of the pocket, and the roller holding surface of the selector. This prevents wind-up (elastic deformation) from occurring during torque transmission, making it possible to configure the engagement clutch with high rigidity and to achieve stable engagement with a simple structure. Furthermore, the elastic member is provided to bias the roller toward the pocket, and the roller holding surfaces of the pocket and support groove are formed at an inclination angle such that when the roller is clamped, a load acts in the direction that moves the roller toward the pocket. As a result, the roller detaches from the inner or outer ring in the free state, thus reducing friction loss and noise. Moreover, when switching from the locked state to the free state, even if torque remains, the selector can be easily rotated with little force, so the locked state can be easily released by rotating the selector and disengaging the roller from the support groove. In addition, by appropriately changing the inclination angle of the roller holding surface in the forward rotation direction and the roller holding surface in the reverse rotation direction in one or both of the pocket and support groove, it is possible to change the torque distribution load in both the forward and reverse rotation directions, making it easy to improve functional stability. Furthermore, because many rollers can be placed in a small space and both forward and reverse locking can be achieved with a single roller, miniaturization is possible, and high torque transmission is possible. Furthermore, by holding the roller on the roller holding surface of the pocket section, the roller holding surface of the support groove section, and the roller holding surface of the selector during engagement, the torque-receiving surface is increased, allowing the torque to be distributed. This reduces the surface pressure acting on the roller and the roller holding surface that clamps it. As a result, it becomes possible to design with inexpensive materials that are resistant to chipping and wear due to impact, and because the roller itself rotates, engagement at the same point is less likely, improving durability and extending the lifespan. Furthermore, by rotating the selector, the roller housed in the pocket can be easily moved radially toward the support groove by the action of the guide surface of the roller housing recess, making it possible to easily switch from the free state to the locked state and to ensure reliable locking. Furthermore, since the roller holding surface of the selector is formed as an inclined surface that becomes larger in diameter as it approaches the guide surface, when switching from the locked state to the free state, the roller biased by the inclined surface of the roller holding surface is more easily guided toward the guide surface, thereby reducing the load when rotating the selector relative to the inner and outer rings. Furthermore, the roller holding surface on the selector side can guide the radially biased roller toward the guide surface along the inclined surface, thereby suppressing wear of the roller holding surface by the roller.

[0010] According to the invention of claim 2, since the pocket portion is formed on the inner circumferential surface of the outer ring and the support groove portion is formed on the outer circumferential surface of the inner ring, even in a configuration in which the inner ring rotates, it is possible to position the selector on the outer ring side. This makes it easier for the drive mechanism that rotates the selector to access the selector, and since the roller is held on the outer ring side, it is not affected by centrifugal force.

[0011] According to the invention of claim 3, by restricting the range of motion of the selector with the pin member and the rotation restricting groove, it is possible to prevent the selector from overrunning and to reliably switch between the free state and the locked state.

[0012] According to the invention of claim 4, since the opening edge of the support groove portion has a C-chamfered or R-chamfered shape, when one of the inner ring and outer ring on which the support groove portion is formed is rotating at a certain rotational speed or higher, even if the roller attempts to move toward the support groove portion due to a misoperation or malfunction of the selector, the roller is repelled toward the pocket portion by the chamfered portion, thereby preventing the inner ring and outer ring from engaging and providing a high level of safety.

[0013] According to the invention of claim 5, when switching from the free state to the locked state, if the phases of the pocket portion and the support groove portion do not match, rotation of the selector is prevented by compression of the standby spring, so the lock standby state can be maintained. As soon as the phases of the pocket portion and the support groove portion match, the biasing force from the standby spring is released, allowing the selector to rotate and lock. Therefore, chipping and damage caused by impact due to abrupt meshing can be reliably prevented, making it possible to achieve a longer service life and ensure high safety.

[0014] According to the invention of claim 6, by providing a position restricting portion that restricts the movable range of the drive rod in the selector drive mechanism, excessive operation of the selector caused by the biasing force resulting from excessive compression of the standby spring can be avoided, and over-running of the selector can be more reliably prevented.

[0015] According to the invention of claim 7, by having a lock position holding function, unexpected rotation of the selector due to vibration or the like can be reliably prevented, and the locked state can be maintained.

[0016] According to the invention of claim 8, since the elastic member is common to each of the plurality of rollers, the number of parts can be reduced and miniaturization is facilitated. Further, it facilitates setting of the biasing force for preventing meshing between the inner ring and the outer ring when one of the inner ring and the outer ring, which is formed with the support groove portion, is rotating at a rotational speed equal to or higher than a predetermined speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] [Figure 1] FIG. 1 is a plan view viewed from the axially front side, showing one configuration example of the selectable clutch according to the first embodiment of the present invention. [Figure 2] FIG. 2 is a partial cross-sectional view along the rotational axis, showing the configuration of the clutch mechanism in the selectable clutch shown in FIG. 1. [Figure 3]Figure 1 shows a partial cross-sectional view along the rotation axis at a different position than that shown in Figure 2, illustrating the configuration of the clutch mechanism in the selectable clutch shown in Figure 1. [Figure 4] This is a plan view showing an enlarged view of the main components of the clutch mechanism in the selectable clutch shown in Figure 1. [Figure 5] This is a vector diagram showing the load acting on the roller in the locked state. [Figure 6A] Figure 1 is a schematic diagram showing the selector clutch in the free state. [Figure 6B] Figure 1 is a schematic diagram showing the state when the drive rod is driven toward the locked position when switching the selector clutch from the free state to the locked state. [Figure 6C] Figure 1 is a schematic diagram showing the selectable clutch in the locked standby state. [Figure 6D] Figure 1 is a schematic diagram showing the selectable clutch when it is switched to the locked state. [Figure 7] This is a perspective view showing another configuration example of the selectable clutch according to the present invention. [Figure 8] This is a plan view taken from the axial front side, showing yet another configuration example of the selectable clutch according to the present invention. [Figure 9] Figure 8 shows a schematic cross-section perpendicular to the rotation axis of the selector drive mechanism in the selectable clutch. [Figure 10A] Figure 8 is a schematic diagram showing the selectable clutch in the locked standby state. [Figure 10B] Figure 6 is a schematic diagram showing the selectable clutch when it is switched to the locked state. [Figure 11] This is a side view showing the configuration of the clutch mechanism in yet another configuration example of the selectable clutch according to the present invention. [Figure 12] Figure 11 is a cross-sectional view of the combination of lines AA. [Figure 13] Figure 11 is a schematic plan view showing a part of the clutch mechanism. [Figure 14A] This diagram schematically shows the state in which the plunger in the lock position holding mechanism is operated. [Figure 14B] This diagram schematically shows the state when the selectable clutch is held in the locked position. [Modes for carrying out the invention]

[0018] <First Embodiment> As shown in Figures 1 and 2, this selectable clutch 100 comprises a clutch mechanism 101 equipped with a selector 150 and a selector drive mechanism 105. The clutch mechanism 101 includes an inner ring 110 and an outer ring 120 that are coaxially rotatable relative to each other, a plurality of rollers 130 positioned between the outer circumferential surface of the inner ring 110 and the inner circumferential surface of the outer ring 120, an elastic member 140 that biases the plurality of rollers 130 radially, and a selector 150 configured to switch between a free state that allows relative rotation of the inner ring 110 and the outer ring 120 in both forward and reverse directions, and a locked state that prohibits relative rotation of the inner ring 110 and the outer ring 120 in both forward and reverse directions. In Figures 1 and 2, C is the axis of rotation.

[0019] In this embodiment, as shown in Figure 3, the inner ring 110 is configured to have a two-stage cylindrical shape, and has a small-diameter cylindrical portion 111 and a large-diameter cylindrical portion 112 that is continuous with one end of the small-diameter cylindrical portion 111. The outer ring 120 comprises an annular plate-shaped base portion 121, a cylindrical support wall portion 122 that protrudes axially from the inner peripheral edge of the base portion 121, and a mounting portion 123 provided on the outer peripheral surface of the base portion 121. A counterbore-shaped recess is formed at the open end of the support wall portion 122, allowing the elastic member 140 to be placed therein.

[0020] The outer circumferential surface of the inner ring 110 and the inner circumferential surface of the outer ring 120 are in close proximity to each other and face each other. In this embodiment, as shown in Figure 4, a plurality of support grooves 115 are formed on the outer circumferential surface of the inner ring 110 at predetermined intervals in the circumferential direction, and a plurality of pockets 125 corresponding to each of the plurality of rollers 130 are formed on the inner circumferential surface of the outer ring 120. In this embodiment, six rollers 130 are arranged at predetermined intervals in the circumferential direction, but the number of support grooves 115 is greater than the number of rollers 130. With a support groove 115 formed on the outer circumferential surface of the inner ring 110 and a pocket 125 formed on the inner circumferential surface of the outer ring 120, even with a configuration that rotates the inner ring 110, the selector 150 can be positioned on the outer ring 120 side. This makes it easy for the selector drive mechanism 105 to access the selector 150, and since the roller 130 is held on the outer ring 120 side, it is not affected by centrifugal force.

[0021] The support groove 115 has a roller holding surface 116 that is inclined with respect to the circumferential direction and is formed to extend in the direction of the rotation axis. In this embodiment, the support groove portion 115 is configured with a cross-sectional shape that can receive a part of the circumferential surface of the roller 130 and support the roller 130, for example, as an arc-shaped groove, and the roller holding surface 116 is configured as the side surface of the groove portion. The opening edge of the support groove 115 has a chamfered shape.

[0022] The pocket portion 125 is configured to accommodate the roller 130 and has a roller holding surface 126 that is inclined with respect to the circumferential direction. In this embodiment, the pocket portion 125 is formed to extend in the direction of the rotation axis from one end face of the support wall portion 122 and is composed of a groove whose cross-sectional shape is, for example, an isosceles trapezoid and a circle tangent to two equal sides of the isosceles trapezoid. The roller holding surface 126 is composed of the side surface of the groove. In this embodiment, the inclination angles with respect to the radial direction of the roller holding surface 126 in the forward rotation direction and the roller holding surface 126 in the reverse rotation direction in the pocket portion 125 are set to be the same size. However, the roller holding surfaces may be formed with a difference in angle. With such a configuration, it becomes possible to change the torque distribution load in both the forward and reverse rotation directions, making it easy to improve functional stability.

[0023] Each of the multiple rollers 130 is configured to protrude axially outward from one end face of the base portion 121 of the outer ring 120 when housed within the pocket portion 125, and a spring mounting groove 131 extending around the entire circumference is formed on the circumferential surface of the protruding portion. As shown in Figure 2, the axial movement of each of the multiple rollers 130 is restricted by the end wall on the other axial end of the pocket portion 125 and the annular plate-shaped stopper plate 180 provided on one axial end.

[0024] The elastic member 140 is common to each of the multiple rollers 130 and is mounted from the inside of the spring mounting groove 131 of the roller 130 so as to bias each roller 130 radially outward toward the pocket portion 125. In other words, the elastic member 140 is provided so that the roller 130 is held on the outer ring 120 side and biases the roller 130 so that the selectable clutch 100 remains in a free state. In this embodiment, the elastic member 140 is composed of an annular garter spring, but it may also be composed of, for example, a ribbon spring. By using a common elastic member 140 for each of the multiple rollers 130, the number of parts is reduced and the size is miniaturized. In addition, it is easy to set the biasing force to prevent the inner ring 110 and the outer ring 120 from meshing when the inner ring 110 is rotating at a rotational speed above a certain level.

[0025] The selector 150 is made of a cylindrical member and is arranged coaxially with the inner ring 110 and outer ring 120, with the outer ring 120 having a pocket portion 125 formed therein, and the inner ring 110 and outer ring 120 moving axially back and forth. The selector 150 is rotatably mounted independently of the inner ring 110 and the outer ring 120, and is configured to rotate to move the roller 130 radially, thereby switching the selectable clutch 100 between a free state and a locked state. In this embodiment, when the selectable clutch 100 is in the free state, rotating the selector 150 in the locking direction (counterclockwise in Figure 1) moves the roller 130 housed in the pocket portion 121 radially inward toward the support groove portion 115. Conversely, when the selectable clutch 100 is in the locked state, rotating the selector 150 in the non-locking direction (clockwise in Figure 1) moves the roller 130 supported by the support groove portion 115 radially outward toward the pocket portion 125.

[0026] The inner circumferential surface of the selector 150 constitutes a roller holding surface 151 that contacts the roller when the roller 130 is supported in the support groove 115 (see Figure 5). As shown in Figure 4, a roller housing recess 152 is formed on the inner circumferential surface of the selector 150, which is configured to accommodate the roller 130 when the roller 130 is housed in the pocket portion 125 and the selectable clutch 100 is in a free state. The roller housing recess 152 has a tapered guide surface 153 configured to move the roller 130 radially toward the support groove 115 as the selector 150 rotates in the locking direction. The roller holding surface 151 has an inclined surface 151a that increases in diameter as it approaches the guide surface 153, from a predetermined position to the connection point with the guide surface 153, that is, as it approaches the guide surface 153, it moves further away from the axis of rotation C.

[0027] This selectable clutch 100 is equipped with a rotation restricting mechanism that limits the range of motion of the selector 150. In this embodiment, the rotation restricting mechanism consists of a pin member 127 erected on one surface of the base portion 121 of the outer ring 120 in which the pocket portion 125 is formed, so as to extend in the axial direction, and a rotation restricting groove portion 156 formed on the inner circumferential surface of the selector 150 so as to extend in the circumferential direction, into which the pin member 127 is slidably inserted.

[0028] As shown in Figure 1, the selector drive mechanism 105 includes a linear actuator 160 equipped with a drive shaft 161 that is driven to move back and forth in one direction (left and right in Figure 1), a drive rod 165 whose one end is connected to the drive shaft 161 and whose other end is connected to a bearing portion 155 provided on the outer circumferential surface of the selector 150, and which is capable of reciprocating in the one direction between a free position that frees the selector clutch 100 and a locked position that holds the selector clutch 100 in a locked state, and a standby spring 170 which is arranged to be elastically deformable in the compression direction when the drive rod 165 is moved in the direction of the locked position and the selector 150 is rotated in the locking direction. In this embodiment, the standby spring 170 is made of a coil spring and is provided with the drive rod 165 inserted through it.

[0029] The actuator 160 has a lock position holding function that fixes the drive rod 165 in the locked position and maintains the position of the selector 150 when the selector clutch 100 is locked. This reliably prevents the selector 150 from rotating unintentionally due to vibration or other reasons, and ensures that the locked state is maintained. Furthermore, this selectable clutch 100 is equipped with a rod position regulating mechanism that restricts the range of motion of the drive rod 165. In this embodiment, as shown in Figure 1, a rod position regulating mechanism is configured by providing a position regulating portion 124 on the mounting portion 123 of the outer ring 120, which is located outward from the lock position in the aforementioned one direction.

[0030] In the above-described selectable clutch 100, the roller holding surface 116 of the support groove 115 and the roller holding surface 126 of the pocket 125 are formed at an inclination angle such that when the roller 130 is clamped, a load acts on the roller 130 in a direction that moves the roller 130 toward the pocket 125. In the locked state, the roller 130 is held by the roller holding surface 116 of the support groove 115, the roller holding surface 126 of the pocket 125, and the roller holding surface 151 of the selector 150.

[0031] To explain in more detail, as shown in Figure 5, when the inner ring 110 and the outer ring 120 mesh, if the roller load acting on the roller 130 is Tr[N], then the roller 130 receives an inner ring normal force Tb[N] represented by (Tr·sinθ1) from the roller holding surface 116 of the support groove 115. θ1 is the angle [°] represented by (90°-θn), and θn is the angle [°] of the load-acting surface that the roller holding surface 116 makes with respect to the radial direction. Furthermore, the pocket portion 125 is subjected to a component force Tc [N] parallel to the roller holding surface 126, represented by (Tb·cosθ2), in the direction along the roller holding surface 126 of the pocket portion 125, and a normal force Td [N] represented by (Tb·sinθ2) in the direction perpendicular to the roller holding surface 126. θ2 is the angle [°] represented by (90°-(θn-θg)), and θg is the angle [°] that the roller holding surface 126 makes with respect to the radial direction. Also, if the coefficient of friction of the roller holding surface 126 is μ, then a frictional force Tf [N] represented by μ·Td acts on the roller holding surface 126. Therefore, an extrusion load Nc[N] represented by (Tc-μTd) acts on the roller 130 in a direction along the roller holding surface 126 of the pocket portion 125 toward the pocket portion 125, and a component force N[N] represented by (Nc·cosθ2) acts radially outward. As a result, the component force N of the extrusion load Nc and the biasing force by the elastic member 140 are received by the roller holding surface 151 (inclined surface 151a) of the selector 150, allowing the inner ring 110 and the outer ring 120 to mesh, and the lock can be released by rotating the selector 150 in the opposite direction to disengage the selector 150 from the roller 130.

[0032] In the selectable clutch 100 according to this embodiment, when the drive rod 165 is in the free position and the selectable clutch 100 is maintained in a free state, as shown in Figure 6A, the roller 130 is biased by the elastic member 140 and positioned within the pocket portion 125 in the outer ring 120 and within the roller housing recess 152 in the selector 150. Therefore, since the roller 130 is detached from the rotating inner ring 110, it is possible to reduce friction loss and noise.

[0033] When switching the selectable clutch 100 from the free state to the locked state, driving the drive rod 165 toward the locked position causes the selector 150 to rotate in the locked direction, as shown in Figure 6B, and the guide surface 153 of the roller housing recess 152 in the selector 150 comes into contact with the roller 130. In this case, because the selector drive mechanism 105 is equipped with a standby spring 170, if the phases of the support groove portion 115 of the inner ring 110 and the pocket portion 125 of the outer ring 120 are not aligned, as shown in Figure 6C, the drive rod 165 is moved to the locked position, while the rotation of the selector 150 is prevented and the standby spring 170 is compressed. Therefore, the selectable clutch 100 maintains the locked standby state. When the inner ring 110 is rotating at a certain rotational speed or higher, even if the roller 130 attempts to move toward the support groove portion 115 due to a misoperation or malfunction of the selector 150, the roller 130 is repelled toward the pocket portion 125 by the chamfered edge of the opening of the support groove portion 115. This reliably prevents chipping or damage due to impact caused by sudden engagement between the inner ring 110 and the outer ring 120, thereby extending the lifespan and ensuring high safety.

[0034] When the phases of the support groove 115 and the pocket 125 align, as shown in Figure 6D, the biasing force from the standby spring 170 is released, causing the selector 150 to rotate in the locking direction, and the roller 130 moves radially toward the support groove 115 due to the action of the guide surface 153 of the roller housing recess 152. At this time, the range of motion of the selector 150 is restricted by the pin member 127 and the rotation restricting groove 156, which prevents overrunning of the selector 150 and ensures reliable switching between the free state and the locked state. Furthermore, by providing a position restricting part 124 that restricts the range of motion of the drive rod 165 when the selectable clutch 100 is held in the locked standby state, excessive compression of the standby spring 170 is prevented, thereby preventing damage to the standby spring 170 itself. Additionally, excessive operation of the selector 150 can be prevented by releasing the biasing force of the standby spring 170, making it possible to more reliably prevent overrunning of the selector 150.

[0035] When the roller 130 moves to the support groove 115, the roller 130 is sandwiched in the circumferential direction between the roller holding surface 116 of the support groove 115 and the roller holding surface 126 of the pocket 125, and the roller holding surface 151 (inclined surface 151a) of the selector 150 comes into contact with the roller 130, causing the inner ring 110 and the outer ring 120 to mesh. This meshing mechanism eliminates wind-up (elastic deformation) during torque transmission, unlike friction clutches, allowing the selectable clutch 100 to be constructed with high rigidity and enabling stable meshing with a simple structure. Furthermore, because the surface pressure acting on the rollers 130 and roller holding surfaces 116, 126, and 151 during meshing can be reduced, it is possible to design the clutch using inexpensive materials that are resistant to chipping and wear due to impact. In addition, since the rollers 130 themselves rotate, meshing at the same point is less likely, improving durability and extending the lifespan. Moreover, because many rollers 130 can be arranged in a small space and both forward and reverse locking can be achieved with a single roller 130, the clutch can be made smaller while also enabling high torque transmission.

[0036] On the other hand, when switching the selectable clutch 100 from the locked state to the free state, the selector 150 is rotated in the non-locking direction by driving the drive rod 165 from the locked position to the free position. At this time, the elastic member 140 is provided to bias the roller 130 toward the pocket portion 125, and the roller holding surface 126 of the pocket portion 125 and the roller holding surface 116 of the support groove portion 115 are formed at an inclination angle such that when the roller 130 is sandwiched, a load acts in the direction that moves the roller 130 toward the pocket portion 125. As a result, even if torque remains, the selector 150 can be easily rotated with a small force, and the locked state can be easily released by disengaging the roller holding surface 151 (inclined surface 151a) of the selector 150 from the roller 130, thereby detaching the roller 130 from the support groove portion 115. Furthermore, since the roller holding surface 151 of the selector has an inclined surface 151a that increases in diameter as it approaches the guide surface 153, from a predetermined position to the connection point with the guide surface 153, the roller 130, which is biased toward the inclined surface 151a when the locked state is released, is easily guided toward the guide surface 153 along the inclined surface 151a without excessively bracing against the roller holding surface 151, thereby reducing the load when rotating the selector 150. Furthermore, when releasing the locked state, wear on the roller holding surface 151 (inclined surface 151a) caused by excessive tension of the roller 130 against the roller holding surface can be suppressed. Furthermore, it is desirable that the inclined surface 151a is formed at least to the point where it contacts the roller holding surface 151 when the roller 130 maintains its locked state. Furthermore, the inclined surface 151a is preferably at an angle of 0 to 5° with respect to the arc surface, and can be any shape when viewed from the side, such as a cycloid curve, a straight line, or an arc with an offset center.

[0037] In the above embodiment, a configuration in which a so-called linear actuator is used as the drive source for the selector drive mechanism 105 was described. However, the selector drive mechanism 105 may also be configured to use a rotary actuator as the drive source, as shown in Figure 7, or to utilize a worm gear mechanism, as shown in Figure 8.

[0038] The clutch mechanism 101 in the selectable clutch 100 shown in Figure 7 has the same configuration as that of the selectable clutch 100 shown in Figure 1, and the same components are denoted by the same reference numerals, so their explanation will be omitted.

[0039] The selector drive mechanism 105 in the selectable clutch 100 shown in Figure 7 comprises a rotary actuator 160 equipped with a drive shaft 161 that can be driven to rotate in both forward and reverse directions, a rotating arm 162 provided on the drive shaft 161, a drive rod 165 whose one end is connected to the rotating arm 162 and whose other end is connected to a bearing portion 155 provided on the outer circumferential surface of the selector 150, and which is capable of reciprocating in one direction between a free position that puts the selectable clutch 100 in a free state and a locked position that holds the selectable clutch 100 in a locked state, and a standby spring 170 arranged to be elastically deformable in the compression direction when the drive rod 165 is moved in the direction of the locked position. In this embodiment, the standby spring 170 is made of a coil spring and is provided with the drive rod 165 inserted through it. Furthermore, the actuator 160 has a lock position holding function that fixes the drive rod 165 in the locked position and maintains the position of the selector 150 when the selectable clutch 100 is locked. This reliably prevents the selector 150 from rotating unintentionally due to vibration or other reasons, and ensures that the locked state is maintained.

[0040] In this selectable clutch 100, when switching the selectable clutch 100 from the free state to the locked state, the drive shaft 161 is rotated in the forward direction to rotate the rotating arm 162, thereby driving the drive rod 165 toward the locked position. At this time, if the phase of the support groove portion 115 of the inner ring 110 and the pocket portion 125 of the outer ring 120 is not aligned, the drive rod 165 is moved to the locked position, while the rotation of the selector 150 is prevented and the spring mechanism 170 is compressed. Therefore, the selectable clutch 100 maintains the locked standby state. When the phases of the support groove 115 and the pocket 125 align, the biasing force from the spring mechanism 170 is released, causing the selector 150 to rotate in the locking direction, and the roller 130 moves radially toward the support groove 115 due to the action of the guide surface 153 of the roller housing recess 152. When the roller 130 moves toward the support groove 115, it is circumferentially sandwiched between the roller holding surface 116 of the support groove 115 and the roller holding surface 126 of the pocket 125, and the roller holding surface 151 (inclined surface 151a) of the selector 150 comes into contact with the roller 130, causing the inner ring 110 and the outer ring 120 to mesh.

[0041] On the other hand, when switching the selectable clutch 100 from the locked state to the free state, the drive shaft 161 is rotated in the reverse direction to rotate the rotating arm 162, thereby driving the drive rod 165 toward the free position. This rotates the selector 150 in the opposite direction to the locked state, disengaging the roller holding surface 151 (inclined surface 151a) of the selector 150 from the roller 130, thereby releasing the roller 130 from the support groove 115 and releasing the locked state.

[0042] The clutch mechanism 101 in the selectable clutch shown in Figure 8 has the same configuration as the selectable clutch 100 shown in Figure 1, except for the configuration of the selector 150. The same components are denoted by the same reference numerals, and their explanation will be omitted. The selector 150 has worm teeth 157 formed on its outer surface and is configured to function as a worm wheel.

[0043] The selector drive mechanism 105 in the selectable clutch shown in Figure 8, as also shown in Figure 9, comprises an actuator 160, a drive rod 165 driven by the actuator 160 so as to be able to rotate in both forward and reverse directions, a worm 163 slidably mounted on the drive rod 165 and meshing with the worm teeth 157 of the selector 150, a spring receiving member 166 provided on the drive rod 165 at one end of the worm 163, and a standby spring 170 provided at one end of the spring receiving member 166 with the drive rod 165 inserted through it. In this embodiment, the actuator 160 has a lock position holding function that maintains rotational torque and the position of the selector 150 when the selectable clutch 100 is locked. This reliably prevents the selector 150 from rotating unintentionally due to vibration or the like, and ensures that the locked state is maintained. The lock position holding function may also be realized by configuring the worm gear mechanism to generate a self-locking phenomenon.

[0044] In this embodiment, when the worm 163 is in a free state, the other end of the worm 163 abuts against one position restricting portion 124, and when the worm 163 moves in such a way that it elastically deforms the standby spring 170 in the compression direction, one end of the spring support member 166 abuts against the other position restricting portion 124, thereby restricting the range of motion of the worm 163.

[0045] In this selectable clutch, when switching the selectable clutch from the free state to the locked state, the drive rod 165 is rotated in the forward direction to rotate the worm 163, thereby rotating the selector 150 in the locked direction. At this time, if the phase of the support groove 115 of the inner ring 110 and the pocket 125 of the outer ring 120 is not aligned, as shown in Figure 10A, the rotation of the selector 150 is prevented, and the worm 163 and spring retainer member 166 are moved relative to the drive rod 165. As a result, the standby spring 170 is compressed, and the selectable clutch maintains the locked standby state. When the phases of the support groove 115 and the pocket 125 align, as shown in Figure 10B, the biasing force from the standby spring 170 is released, causing the worm 163 and spring receiving member 166 to move to the free position, and the selector 150 to rotate in the locking direction. As a result, the roller 130 moves radially toward the support groove 115 due to the action of the guide surface 153 of the roller housing recess 152. When the roller 130 moves toward the support groove 115, it is sandwiched circumferentially between the roller holding surface 116 of the support groove 115 and the roller holding surface 126 of the pocket 125, and the roller holding surface 151 (inclined surface 151a) of the selector 150 comes into contact with the roller 130, causing the inner ring 110 and the outer ring 120 to mesh.

[0046] On the other hand, when switching the selectable clutch from the locked state to the free state, the drive rod 165 is rotated in the reverse direction to rotate the worm 163, thereby rotating the selector 150 in the anti-lock direction. This causes the roller holding surface 151 (inclined surface 151a) of the selector 150 to disengage from the roller 130. As a result, the roller 130 is disengaged from the support groove 115 by the load directed toward the pocket portion 125 from the roller holding surface 126 of the pocket portion 125 and the roller support surface 116 of the support groove portion 115, as well as the biasing force of the elastic member 140, thereby releasing the locked state.

[0047] In the embodiments described above, a configuration in which a standby spring is provided in the selector drive mechanism has been described, but a configuration in which the clutch mechanism is equipped with a standby spring is also possible. As shown in Figures 11 to 13, the clutch mechanism 101 of this embodiment is configured such that the outer ring 120, the selector 150, and the rotating plate 185 constituting the selector drive mechanism are arranged in front of and behind each other in the axial direction. The clutch mechanism 101 has basically the same configuration as those of the above embodiments, and the same reference numerals are used for the same components as those of the above embodiments, so their description is omitted.

[0048] One surface of the selector 150 has a plurality of standby spring placement grooves 154 that are formed concentrically with the rotation axis C and extend in the circumferential direction. The standby spring placement grooves 154 are formed to be arranged at predetermined intervals in the circumferential direction at a position radially outward from the roller housing recess 152. A coil-shaped standby spring 170 is positioned within the standby spring arrangement groove 154, and a pin member 171 is positioned at one end in the circumferential direction (the clockwise end in Figures 11 and 12). The pin member 171 is fixed to the rotating plate 185. Furthermore, a plurality of guide grooves 158 extending in the circumferential direction are formed on one surface of the selector 150, and a connecting pin member 187 that connects the rotating plate 185 and the outer ring 120 is slidably inserted through each guide groove 158.

[0049] The rotating plate 185 has a pin member insertion groove 186 that extends in the circumferential direction and through which a connecting pin member 187 is slidably inserted, corresponding to the guide groove 158 of the selector 150. In this clutch mechanism 101, a lock position holding mechanism 190 is provided for holding the selector 150 in the locked position when the selectable clutch is locked.

[0050] The lock position holding mechanism 190 comprises a plunger 191 having a plunger hole that opens radially outward, a biasing means 193 housed in the plunger hole and biasing the plunger 191 radially inward, and a spring receiving portion 194 fixed to the axial outer end of the biasing means 193. The plunger 191 is slidably housed in a plunger housing hole formed to extend radially from one guide groove 158 of the rotating plate 185 and open to the outer circumferential surface of the rotating plate 185. The spring retainer 194 is fixed to the rotating plate 185 so that the tip of the plunger 191 abuts against the radially inward circumferential surface of the pin member insertion groove 186. The tip of the plunger 191 that is exposed into the pin member insertion groove 186 is formed in a conical shape and moves in a direction that compresses the biasing means 193 by pressing the connecting pin member 187 when the selector 150 is rotated in the locking direction due to the action of the tapered surface.

[0051] As shown in Figure 13, when the selectable clutch is held in the free state, the plunger 191 is positioned on the locking side (counterclockwise in Figure 13) relative to the connecting pin member 187. When the selector 150 rotates in the locking direction with the phases of the support groove 115 of the inner ring 110 and the pocket 125 of the outer ring 120 aligned, the plunger 191 moves radially outward so as to ride over the connecting pin member 187, as shown in Figure 14A. Subsequently, when the selectable clutch is locked, the plunger 191 moves over the connecting pin member 187 and moves in the anti-locking direction (clockwise) relative to the connecting pin member 187, as shown in Figure 14B. This reliably prevents the selector 150 from unintentionally rotating in the anti-locking direction due to vibration or the like, and makes it possible to mechanically maintain the locked state.

[0052] In this clutch mechanism 101, when the selector 150 is rotated in the locking direction to switch the selectable clutch from the free state to the locked state, if the phases of the support groove 115 of the inner ring 110 and the pocket 125 of the outer ring 120 do not match, the rotation of the selector 150 is blocked. At the same time, as the rotating plate rotates, the pin member 171 presses the standby spring 170 in a compressive direction, and the sectorable clutch maintains the locked standby state. As soon as the phases of the support groove 115 of the inner ring 110 and the pocket 125 of the outer ring 120 match, the spring force of the standby spring 170 is released, causing the selector 150 to rotate in the locking direction. As a result, the roller 130 is held by the support groove 115, the pocket 125 and the selector 150, and the inner ring 110 and outer ring 120 engage.

[0053] The selector drive mechanism may be a linear or rotary actuator, similar to the selectable clutch according to the above embodiment, or a worm gear type selector drive mechanism. Alternatively, it may be configured to directly drive rotation using an appropriate gear mechanism, or it may be configured as a shift-by-cable system in which the user directly drives rotation by operating a lever. Furthermore, by using an actuator with a position-holding function, the selectable clutch may be configured to have a locked position-holding function. In this case, the clutch mechanism may not have a locked position-holding mechanism.

[0054] Although 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 described in the claims. For example, in each of the embodiments described above, a configuration in which the outer ring is fixed and the inner ring rotates has been described, but a configuration in which the inner ring is fixed and the outer ring rotates, or a configuration in which both the inner and outer rings rotate, may also be used. Furthermore, in the embodiments described above, a configuration was described in which a support groove is formed on the outer circumferential surface of the inner ring and a pocket is formed on the inner circumferential surface of the outer ring, and an elastic member is arranged to bias the roller radially outward. However, a configuration in which a support groove is formed on the inner circumferential surface of the outer ring and a pocket is formed on the outer circumferential surface of the inner ring, and an elastic member is arranged to bias the roller radially inward, is also possible. Furthermore, although the above embodiments described a configuration in which an elastic member common to multiple rollers was used, a configuration in which multiple elastic members corresponding to each of the multiple rollers may also be used. Furthermore, while the above embodiments have described a selectable clutch configured to allow switching between two operating modes, a bidirectional free state and a bidirectional locked state, the selector may also be configured to allow switching between three to four operating modes, including a unidirectional locked state, by arranging rollers to be supported in each of two adjacent support grooves, providing a first pocket and a second pocket corresponding to each of the two rollers, and further configuring the selector to allow radial movement of either one or both of the two rollers. [Industrial applicability]

[0055] The selectable clutch according to the present invention is extremely useful, for example, in the construction of a vehicle parking lock system. That is, since the selectable clutch according to the present invention does not release the lock state unless the selector releases its hold on the roller, even if torque is input due to the condition of the road surface on which the vehicle is parked or for other reasons, the lock state will not be released, and the vehicle's stopped state can be maintained. Furthermore, since the lock state is released when the selector disengages from the roller, the lock state can be easily released even if torque is acting on the inner or outer wheel due to torque load, for example, on an incline. [Explanation of symbols]

[0056] 100 ··· Selectable clutch 101... Clutch mechanism 105... Selector drive mechanism 110 ··· Internal circle 111 ··· Small diameter cylindrical part 112 ··· Large diameter cylindrical section 115... Support groove 116... Roller holding surface 120 ··· Outer ring 121 ··· Base part 122 ··· Supporting wall part 123 ··· Mounting part 124 ... position regulation section 125 ··· Pocket section 126... Roller holding surface 127... Pin component 130 ··· Laura 131... Spring mounting groove 140 ··· Elastic material 150 ··· Selector 151... Roller holding surface 151a... Inclined surface 152 ··· Roller housing recess 153 ··· Guide surface 154 ··· Standby spring placement groove 155...Bearing section 156 ··· Rotation regulating groove 157 ··· Warm teeth 158 ··· Guide groove section 160 ··· Actuator 161... Drive shaft 162 ··· Rotating Arm 163 ··· Warm 165 ··· Drive rod 166 ··· Spring support member 170 ··· Standby Spring 171... Pin component 180 ··· Stopper plate 185 ··· Rotating plate 186... Pin member insertion groove 187 ··· Connecting pin component 190 ··· Lock position holding mechanism 191 ··· Plunger 193... biasing means 194 ··· Spring support section C...Rotation axis center

Claims

1. A selectable clutch comprising a cylindrical inner ring and a cylindrical outer ring, which are coaxially rotatable relative to each other, a plurality of rollers disposed between the inner ring and the outer ring, and an elastic member that biases the rollers in the radial direction, A pocket portion is formed on one of the outer circumferential surfaces of the inner ring and the inner circumferential surface of the outer ring, having a roller-holding surface that is inclined with respect to the circumferential direction and is configured to accommodate the roller, while a support groove portion is formed on the other of the outer circumferential surfaces of the inner ring and the inner circumferential surface of the outer ring, having a roller-holding surface that is inclined with respect to the circumferential direction. The elastic member is provided to bias the roller toward the pocket portion, The inner ring and the outer ring, one of which the pocket portion is formed, are provided with a selector that is rotatable independently of the inner ring and the outer ring in the axial direction, the selector having a roller holding surface that contacts the roller when the roller is supported in the support groove, and is configured to switch between a free state that allows relative rotation of the inner ring and the outer ring and a locked state that prohibits relative rotation of the inner ring and the outer ring by moving the roller radially. The roller holding surface of the pocket portion and the roller holding surface of the support groove portion are formed at an inclination angle such that when the roller is clamped, a load acts in a direction that moves the roller toward the pocket portion. In the locked state, the roller is configured to be held by the roller holding surface of the support groove, the roller holding surface of the pocket, and the roller holding surface of the selector. The selector has a roller housing recess configured to accommodate the roller when the roller is housed in the pocket and the selectable clutch is in a free state, The roller housing recess has a guide surface configured to move the roller radially toward the support groove as the selector rotates, A selectable clutch characterized in that the roller holding surface of the selector is formed as an inclined surface that becomes larger in diameter as it approaches the guide surface.

2. The selectable clutch according to claim 1, characterized in that the pocket portion is formed on the inner circumferential surface of the outer ring and the support groove portion is formed on the outer circumferential surface of the inner ring.

3. A pin member extending in the axial direction is provided on one of the inner ring and the outer ring in which the pocket portion is formed. The selectable clutch according to claim 1, characterized in that the selector is provided with a rotation restricting groove into which the pin member is slidably inserted and which restricts the range of motion of the selector.

4. The selectable clutch according to claim 1, characterized in that the opening edge of the support groove portion has a C-chamfered or R-chamfered shape.

5. The selectable clutch according to claim 1, further characterized by comprising a standby spring that is elastically deformable in the compression direction when the selector is rotated in the locking direction.

6. The selector is provided with a selector drive mechanism that rotates independently of the inner ring and the outer ring, The selector drive mechanism includes a drive rod connected to the selector and capable of reciprocating between a free position that disengages the engagement clutch and a locked position that holds the engagement clutch in a locked state. The standby spring is composed of a coil spring through which the drive rod is inserted. The selectable clutch according to claim 5, further comprising a position restricting portion for restricting the range of motion of the drive rod.

7. The selectable clutch according to claim 1, characterized in that it has a lock position holding function that holds the position of the selector when the selectable clutch is in a locked state.

8. The selectable clutch according to claim 1, characterized in that the elastic member is common to each of the plurality of rollers.

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