Selectable clutch

Abstract

To provide an engaging clutch that has a simple structure and can be made compact and long-life while reducing friction loss and preventing noise generation.SOLUTION: A selectable clutch 100 comprising a selector 150 is so constituted that: a support groove part 111 is formed at one of an inner ring 110 and an outer ring 120 and a pocket part 112 is formed at the other; an elastic member 150 is provided to energize a roller 130 arranged between the inner ring 110 and the outer ring 120 toward the pocket part 112; a roller retaining surface 112 of the support groove part 111 and a roller retaining surface 122 of the pocket part 112 are formed at an inclination angle in which a load placed on the pocket part 125 acts on the roller 130 when the roller 130 is held therebetween; and the roller 130 is retained by the support groove part 111, the pocket part 112 and the selector 150 in a locked state.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art As a clutch for transmitting or blocking torque from an input shaft side to an output shaft side, for example, a ratchet-type dog clutch that connects the input shaft side and the output shaft side by mechanical meshing is known.

[0003] One known example of such a clutch is one that includes a ratchet mechanism consisting of a plurality of pawls, which are torque transmission members rotatably mounted on the inner circumference of the outer ring, and teeth that are mounted on the outer circumference of the inner ring and engage with the pawls (see, for example, Patent Documents 1 to 4, etc.). For example, the ratchet-type clutch described in Patent Document 1 includes a plurality of first pawl members biased radially inward by a spring, and a plurality of second pawl members biased radially inward by a spring and having a circumferential orientation different from that of the first pawl members, wherein the first pawl members lock the rotation of one side of the inner ring while allowing the rotation of the other side of the inner ring, and the second pawl members allow the rotation of one side of the inner ring while locking the rotation of the other side of the inner ring. In addition, an annular switching plate is arranged coaxially with the inner ring adjacent to one side in the central axial direction of the inner ring, and by rotating the switching plate, the combination of meshed and non-meshed states of the first and second claw members with respect to the teeth portion of the inner ring can be changed.

[0004] Also known as a ratchet-type clutch is one in which, for example, a pocket plate and a notch plate, each having a flat clutch surface, are arranged so that their clutch surfaces face each other and can rotate relative to one another, and struts are accommodated in each of a number of accommodating recesses formed in the clutch surface of the pot plate, and a number of notches (engagement recesses) are formed in the clutch surface of the notch plate (see, for example, Patent Document 5, etc.). In this ratchet-type clutch, each strut is biased toward the notch plate by a spring provided in the accommodating recess. When the notch plate rotates relative to the pocket plate in the engagement direction, a part 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. In addition, a select plate that is rotatable relative to the pocket plate is disposed between the pocket plate and the notch plate, and the relative rotation of the select plate makes it possible to switch between a state in which power can be transmitted and a state in which power cannot be transmitted. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2021-156432 A [Patent Document 2] JP 2022-047794 A [Patent Document 3] Patent Publication No. 2022-038806 [Patent Document 4] JP 2022-165688 A [Patent Document 5] Patent Publication No. 2021-102980 Summary of the Invention [Problem to be solved by the invention]

[0006] Thus, in a selectable clutch that is configured to be switchable between a free state and a locked state, 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 the pawl members and struts are configured to be biased in the locking direction by springs, if the selector is driven for some reason to enter a locked state when the inner ring is rotating relative to the outer ring in a free state, there is a risk that chipping or damage may occur due to the impact caused by sudden engagement. Furthermore, in a ratchet-type clutch equipped with a pawl member, if the inner ring is rotated and the pawl member is provided on the outer ring side and the engagement portion is provided on the inner ring side, the selector must be located on the inner ring side, making it difficult to approach the selector from a drive source such as an actuator. On the other hand, if the pawl member is provided on the inner ring side and the engagement portion is provided on the outer ring side, the pawl member will also rotate together with the inner ring and will be affected by centrifugal force. Furthermore, in a ratchet-type clutch equipped with pawl members, when configuring it as a two-way clutch, it is necessary to arrange the pair of pawl members opposite each other, which causes problems such as the clutch becoming large and making it difficult to handle high torque. There is also the problem that the surface of the pawl members that receives torque is narrow and prone to high surface pressure, raising concerns about chipping and wear due to impact.

[0007] The present invention has been made based on the above-mentioned circumstances, and has an object to provide a selectable clutch with a simple structure that can be made compact and have a long life while reducing friction loss and preventing noise generation. [Means for solving the problem]

[0008] The present invention relates to a selectable clutch including a cylindrical inner ring and a cylindrical outer ring that are coaxially and relatively rotatably arranged, a plurality of rollers arranged between the inner ring and the outer ring, and an elastic member that radially biases the rollers, wherein a pocket portion having a roller holding surface inclined with respect to the circumferential direction and configured to be able to accommodate the rollers is formed on one of the outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring, and a support groove portion having a roller holding surface inclined with respect to the circumferential direction is formed on the other of the outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring, the elastic member is provided to bias the rollers toward the pocket portion, and is arranged axially back and forth with respect to the one of the inner ring and the outer ring where the pocket portion is formed, so as to be rotatable independently of the inner ring and the outer ring. The problem is solved by comprising a selector having a roller retaining surface that abuts against the roller when the roller is supported in the support groove portion, and is configured to be able to switch between a free state in which relative rotation of the inner ring and the outer ring is permitted and a locked state in which relative rotation of the inner ring and the outer ring is prohibited by moving the roller in a radial direction, the roller retaining surface of the pocket portion and the roller retaining surface of the support groove portion being formed at an inclination angle such that, when the roller is sandwiched, a load acts in a direction that moves the roller towards the pocket portion, and the roller retaining surface of the selector is configured so that in the locked state, the roller is retained by the roller retaining surface of the support groove portion, the roller retaining surface of the pocket portion and the roller retaining surface of the selector. Effect of the Invention

[0009] According to the invention of claim 1, in the locked state, the rollers are 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. This prevents windup (elastic deformation) from occurring when torque is transmitted, makes it possible to configure the meshing clutch as having high rigidity, and enables stable meshing to be achieved with a simple structure. Moreover, the elastic member is provided to bias the roller toward the pocket, and the roller holding surfaces of the pocket and the support groove are formed at an inclination angle such that a load acts in a direction that moves the roller toward the pocket when the roller is pinched, so that the roller is released from the inner or outer ring in the free state, thereby reducing friction loss and noise, and further, since the selector can be easily rotated with a small force even if torque remains when switching from the locked state to the free state, the roller can be released from the support groove by rotating the selector to easily release the locked state. Also, by appropriately changing the inclination angle of the roller holding surface in the forward direction and the roller holding surface in the reverse direction in one or both of the pocket and the support groove, it is possible to change the torque distribution load in both the forward and reverse directions, and it is possible to easily improve the functional stability. Furthermore, since many rollers can be arranged in a small space and locking in both forward and reverse directions can be achieved with a single roller, it is possible to achieve a compact design and transmit high torque. Furthermore, by holding the rollers with the roller holding surfaces of the pocket, the support groove, and the selector during meshing, the torque is distributed over a larger area, reducing the surface pressure acting on the rollers and the roller holding surfaces that hold the rollers in place. This makes it possible to design the rollers using inexpensive materials that are resistant to chipping and wear due to impact, and because the rollers themselves rotate, they are less likely to mesh at the same point, improving durability and enabling a longer lifespan.

[0010] According to the invention of claim 2, the pocket portion is formed on the inner surface of the outer ring and the support groove portion is formed on the outer surface of the inner ring, so that even in a configuration in which the inner ring is rotated, the selector can be positioned on the outer ring side. This makes it easier for the drive mechanism that rotates the selector to approach 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 rotating the selector, the roller housed in the pocket portion can be easily moved radially toward the support groove portion by the action of the guide surface of the roller accommodating recess, making it possible to easily switch from the free state to the locked state and to achieve reliable locking.

[0012] According to the invention of claim 4, by restricting the movable range of the selector with the pin member and the rotation restriction groove portion, it is possible to prevent overrunning of the selector, and switching between the free state and the locked state can be performed reliably.

[0013] According to the invention of claim 5, the opening edge of the support groove has a C-chamfered shape or an R-chamfered shape, so that when one of the inner and outer rings in which the support groove is formed is rotating at a certain rotational speed or above, even if the roller attempts to move toward the support groove portion due to an erroneous operation or malfunction of the selector, the roller is repelled toward the pocket portion by the chamfered portion, thereby preventing the inner and outer rings from meshing with each other and ensuring high safety.

[0014] According to the invention of claim 6, when switching from the free state to the locked state, if the phase of the pocket portion and the support groove portion are not aligned, the standby spring is compressed to prevent the selector from rotating, so that the selector can be maintained in the locked standby state, and as soon as the phase of the pocket portion and the support groove portion are aligned, the biasing force of the standby spring is released to rotate the selector and lock it. This makes it possible to reliably prevent chipping or damage caused by impact due to sudden meshing, and it is possible to achieve a long life and ensure high safety.

[0015] According to the invention of claim 7, by providing a position regulating portion that regulates the movable range of the drive rod in the selector drive mechanism, excessive operation of the selector due to the biasing force caused by excessive compression of the standby spring can be avoided, and overrunning of the selector can be prevented more reliably.

[0016] According to the invention as defined in claim 8, by having a function for maintaining the locked position, it is possible to reliably prevent the selector from rotating unexpectedly due to vibration or the like, and to maintain the locked state.

[0017] According to the invention of claim 9, since the elastic member is common to each of the rollers, it is possible to reduce the number of parts and facilitate miniaturization. Also, it is easy to set the biasing force for preventing the inner ring and the outer ring from meshing when one of the inner ring and the outer ring, in which the support groove is formed, rotates at a certain rotational speed or higher. [Brief description of the drawings]

[0018] [Figure 1] 1 is a plan view showing one configuration example of a selectable clutch according to a first embodiment of the present invention, as viewed from the axial front side. FIG. [Diagram 2] 2 is a partial cross-sectional view taken along the axis of rotation, showing the configuration of a clutch mechanism in the selectable clutch shown in FIG. 1. [Diagram 3] 3 is a partial cross-sectional view taken along the rotation axis at a position different from that in FIG. 2, showing the configuration of a clutch mechanism in the selectable clutch shown in FIG. 1. [Figure 4] 2 is an enlarged plan view showing a main configuration of a clutch mechanism in the selectable clutch shown in FIG. 1. [Diagram 5] 11 is a vector diagram showing a load acting on a roller in a locked state. [Figure 6A] 2 is a schematic diagram of the selectable clutch shown in FIG. 1 in a free state. FIG. [Figure 6B] 4 is a schematic diagram showing a state when a drive rod is driven toward a locked position in switching the selectable clutch shown in FIG. 1 from a free state to a locked state. FIG. [Figure 6C] 2 is a schematic diagram of the selectable clutch shown in FIG. 1 in a lock standby state. [Figure 6D]2 is a schematic diagram of the selectable clutch shown in FIG. 1 when switched to a locked state. [Figure 7] FIG. 4 is a perspective view showing another example of the configuration of the selectable clutch according to the present invention. [Figure 8] FIG. 11 is a plan view showing still another configuration example of the selectable clutch according to the present invention, as viewed from the axial front side. [Figure 9] 9 is a schematic diagram showing a cross section perpendicular to the rotation axis of a selector drive mechanism in the selectable clutch shown in FIG. 8. [Figure 10A] 9 is a schematic diagram of the selectable clutch shown in FIG. 8 in a lock standby state. [Figure 10B] 7 is a schematic diagram of the selectable clutch shown in FIG. 6 when switched to a locked state. [Figure 11] FIG. 11 is a side view showing the configuration of a clutch mechanism in still another configuration example of the selectable clutch according to the present invention. [Figure 12] 12 is a cross-sectional view taken along line AA in FIG. 11. [Figure 13] 12 is a plan view showing a schematic view of a part of the clutch mechanism shown in FIG. 11. [Figure 14A] 13 is a diagram illustrating a state in which a plunger in the lock position maintaining mechanism is actuated. FIG. [Figure 14B] FIG. 4 is a diagram illustrating a state in which the selectable clutch is held in a locked state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] First Embodiment As shown in FIGS. 1 and 2, the selectable clutch 100 includes a clutch mechanism 101 having 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 arranged to be relatively rotatable, a plurality of rollers 130 arranged between the outer peripheral surface of the inner ring 110 and the inner peripheral surface of the outer ring 120, an elastic member 140 that radially biases the plurality of rollers 130, and a selector 150 that is configured to be switchable between a free state that permits relative rotational movement in both forward and reverse directions between the inner ring 110 and the outer ring 120 and a locked state that prohibits relative rotational movement in both forward and reverse directions between the inner ring 110 and the outer ring 120. C in Figures 1 and 2 is the rotation axis.

[0020] In this embodiment, as shown in FIG. 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 continuous with one end of the small diameter cylindrical portion 111. The outer ring 120 includes an annular plate-shaped base portion 121, a cylindrical support wall portion 122 that protrudes and extends in the axial direction from the inner peripheral edge of the base portion 121, and an attachment portion 123 provided on the outer peripheral surface of the base portion 121. A countersunk recess is formed at the open end of the support wall portion 122, and an elastic member 140 can be disposed therein.

[0021] The outer peripheral surface of the inner ring 110 and the inner peripheral surface of the outer ring 120 face each other closely, and in this embodiment, as shown in Fig. 4, a plurality of support grooves 115 are formed at a predetermined interval in the circumferential direction on the outer peripheral surface of the inner ring 110, and a plurality of pockets 125 corresponding to each of the plurality of rollers 130 are formed on the inner peripheral surface of the outer ring 120. Here, in this embodiment, six rollers 130 are arranged at positions spaced apart in the circumferential direction, but the number of support grooves 115 formed is greater than the number of rollers 130. By forming a support groove portion 115 on the outer peripheral surface of the inner ring 110 and a pocket portion 125 on the inner peripheral surface of the outer ring 120, it is possible to arrange the selector 150 on the outer ring 120 side even in a configuration in which the inner ring 110 is rotated, making it easy for the selector drive mechanism 105 to approach the selector 150, and since the roller 130 is held on the outer ring 120 side, it is not affected by centrifugal force.

[0022] The support groove portion 115 has a roller holding surface 116 that is inclined with respect to the circumferential direction, and is formed so as to extend in the direction of the rotation axis. In this embodiment, the support groove portion 115 is configured as a concave groove having a cross-sectional shape, for example an arc-shaped cross-section, that can receive a portion of the peripheral surface of the roller 130 to support the roller 130, and the roller holding surface 116 is configured by the side surface of the groove portion. The opening edge of the support groove 115 has a C-chamfered shape.

[0023] The pocket portion 125 has a roller holding surface 126 that is configured to be able to accommodate the roller 130 and is inclined relative to the circumferential direction. In this embodiment, the pocket portion 125 is formed by a groove that is formed to extend in the rotation axis direction from one end face of the support wall portion 122 and has a cross-sectional shape that combines, for example, an isosceles trapezoid and a circle that is tangent to two equal sides of the isosceles trapezoid. The roller holding surface 126 is formed by the side surface of the groove. In this embodiment, 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 configured to have the same inclination angle relative to the radial direction, but each roller holding surface may be formed with an angle difference. With such a configuration, it is possible to change the torque load sharing in both the forward rotation direction and the reverse rotation direction, and it is possible to easily improve the functional stability.

[0024] Each of the multiple rollers 130 is configured so as 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 peripheral surface of the protruding portion. As shown in FIG. 2, the axial movement of each of the rollers 130 is restricted by an end wall on the other axial end side of the pocket portion 125 and an annular stop plate 180 provided on one axial end side.

[0025] The elastic member 140 is common to each of the rollers 130, and is attached to the spring attachment groove 131 of the roller 130 from the inner side so as to urge 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 urges the roller 130 so as to maintain the selectable clutch 100 in a free state. In this embodiment, the elastic member 140 is configured as a ring-shaped garter spring, but may be configured as, for example, a ribbon spring. The number of parts is reduced and the size is made smaller by using a common elastic member 140 for each of the rollers 130. In addition, it is easy to set the biasing force to prevent the inner ring 110 and the outer ring 120 from meshing with each other when the inner ring 110 rotates at a certain rotation speed or higher.

[0026] The selector 150 is formed of a cylindrical member, and is arranged coaxially with the inner ring 110 and the outer ring 120, axially front and rear to the outer ring 120 in which the pocket portion 125 is formed. The selector 150 is provided rotatably independent of the inner ring 110 and the outer ring 120, and is configured to move the rollers 130 in the radial direction by rotating, 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, the selector 150 is rotated in the lock direction (counterclockwise in FIG. 1) to move the rollers 130 accommodated in the pocket portion 121 radially inward toward the support groove portion 111. When the selectable clutch 100 is in the locked state, the selector 150 is rotated in the counterlock direction (clockwise in FIG. 1) to move the rollers 130 supported by the support groove portion 115 radially outward toward the pocket portion 125.

[0027] The inner circumferential surface of the selector 150 constitutes a roller holding surface 151 that comes into contact with the roller 130 when the roller 130 is supported by the support groove portion 115 (see FIG. 5). As shown in FIG. 4, a roller accommodating recess 152 is formed on the inner peripheral surface of the selector 150 so as to be capable of accommodating the roller 130 when the roller 130 is accommodated in the pocket portion 125 and the selectable clutch 100 is in a free state. The roller accommodating 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.

[0028] The selectable clutch 100 is provided with a rotation restricting mechanism that restricts the movable range of the selector 150. In this embodiment, the rotation restriction mechanism is composed of a pin member 127 that is erected so as to extend in the axial direction on one surface of the base portion 121 of the outer ring 120 in which the pocket portion 125 is formed, and a rotation restriction groove portion 156 that is formed so as to extend in the circumferential direction on the inner surface of the selector 150 and into which the pin member 127 is slidably inserted.

[0029] As shown in FIG. 1, the selector drive mechanism 105 comprises a linear actuator 160 having a drive shaft 161 that can be driven to move back and forth in one direction (left and right direction in FIG. 1), a drive rod 165 having one end connected to the drive shaft 161 and the other end connected to a bearing portion 155 provided on the outer peripheral surface of the selector 150, and capable of reciprocating in the one direction between a free position where the selectable clutch 100 is freed and a locked position where the selectable clutch 100 is held in a locked state, and a standby spring 170 arranged so as to be elastically deformable in the compression direction when the drive rod 165 is moved toward the locked position to rotate the selector 150 in the locked direction. In this embodiment, the standby spring 170 is made of a coil spring, and the drive rod 165 is inserted therethrough.

[0030] The actuator 160 has a lock position maintaining function that fixes the drive rod 165 to the locked position to maintain the position of the selector 150 when the selectable clutch 100 is in the locked state. This reliably prevents the selector 150 from accidentally rotating due to vibration or the like, and enables the lock state to be maintained. In addition, the selectable clutch 100 is provided with a rod position restriction mechanism that restricts the range of movement of the drive rod 165. In this embodiment, as shown in FIG. 1, a position restricting portion 124 is provided on an attachment portion 123 of an outer ring 120 located outward from the lock position in the one direction, thereby forming a rod position restricting mechanism.

[0031] Thus, in the above-mentioned selectable clutch 100, the roller retaining surface 116 of the support groove portion 115 and the roller retaining surface 126 of the pocket portion 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 moving the roller 130 toward the pocket portion 125, and the roller 130 is retained by the roller retaining surface 116 of the support groove portion 115, the roller retaining surface 126 of the pocket portion 125, and the roller retaining surface 151 of the selector 150 in the locked state.

[0032] 5, if the roller load acting on roller 130 when inner ring 110 and outer ring 120 are engaged is Tr [N], roller 130 receives inner ring normal force Tb [N] expressed as (Tr·sinθ1) from roller retaining surface 116 of support groove portion 115. θ1 is an angle [°] expressed as (90°-θn), and θn is a load acting surface angle [°] that roller retaining surface 116 makes with the radial direction. Furthermore, a component force Tc [N] parallel to the roller holding surface 126, expressed as (Tb·cosθ2), acts on the pocket portion 125 from the roller 130 in a direction along the roller holding surface 126 of the pocket portion 125, and a normal force Td [N] expressed as (Tb·sinθ2) acts on the roller holding surface 126 in a direction perpendicular to the roller holding surface 126. θ2 is an angle [°] expressed as (90°-(θn-θg)), and θg is an angle [°] that the roller holding surface 126 makes with the radial direction. Furthermore, if the friction coefficient of the roller holding surface 126 is μ, a frictional force Tf [N] expressed as μ·Td acts on the roller holding surface 126. Therefore, a pushing load Nc [N] shown as (Tc - μTd) toward the pocket portion 125 acts on the roller 130 in a direction along the roller holding surface 126 of the pocket portion 125, and a component force N [N] shown as (Nc cos θ2) acts radially outward. Therefore, the component force N of the pushing load Nc and the biasing force of the elastic member 140 are received by the roller holding surface 151 of the selector 150, so that the inner ring 110 and the outer ring 120 can be engaged with each other, and the lock can be released by rotating the selector 150 in the counter-locking direction to remove the selector 150 from the roller 130.

[0033] In the selectable clutch 100 according to this embodiment, when the drive rod 165 is located at the free position and the selectable clutch 100 is maintained in a free state, as shown in Fig. 6A, the rollers 130 are biased by the elastic members 140 and positioned in the pockets 125 of the outer ring 120 and in the roller accommodating recesses 152 of the selector 150. Therefore, since the rollers 130 are disengaged from the rotating inner ring 110, it is possible to reduce friction loss and noise.

[0034] When switching the selectable clutch 100 from a free state to a locked state, the drive rod 165 is driven toward the locked position, and as shown in FIG. 6B, the selector 150 rotates in the locking direction and the guide surface 153 of the roller accommodating recess 152 in the selector 150 abuts against the roller 130. At this time, since the selector drive mechanism 105 is provided with the 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 Fig. 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 above, even if roller 130 attempts to move toward support groove 115 due to an erroneous operation or malfunction of selector 150, roller 130 is repelled toward pocket 125 by the chamfered portion because the opening edge of support groove 115 has a C-chamfered shape. This makes it possible to reliably prevent chipping or damage caused by impact due to sudden meshing between inner ring 110 and outer ring 120, making it possible to achieve a long life and ensure high safety.

[0035] When the phases of support groove portion 115 and pocket portion 125 are aligned, as shown in FIG. 6D, the biasing force of standby spring 170 is released, causing selector 150 to rotate in the locking direction, and roller 130 moves radially toward support groove portion 115 due to the action of guide surface 153 of roller accommodating recess 152. At this time, the movable range of the selector 150 is restricted by the pin member 127 and the rotation restriction groove portion 156, thereby making it possible to prevent overrunning of the selector 150 and ensure switching between the free state and the locked state. In addition, by providing a position regulating portion 124 that regulates the range of movement 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, and by releasing the biasing force of the standby spring 170, excessive operation of the selector 150 is avoided, making it possible to more reliably prevent overrunning of the selector 150.

[0036] When roller 130 moves into support groove portion 115, roller 130 is circumferentially sandwiched between roller holding surface 116 of support groove portion 115 and roller holding surface 126 of pocket portion 125, and roller holding surface 151 of selector 150 abuts against roller 130, so that inner ring 110 and outer ring 120 mesh with each other. By using such an engagement method, windup (elastic deformation) does not occur during torque transmission as in the case of a friction clutch, and the selectable clutch 100 can be constructed to have high rigidity, and stable engagement can be achieved with a simple structure. Moreover, since the surface pressure acting on the roller 130 and the roller holding surfaces 116, 126, 151 during engagement can be reduced, it is possible to design it using inexpensive materials that are resistant to chipping and wear due to impact, and since the roller 130 itself rotates, it is difficult for the rollers 130 to engage at the same point, which improves durability and allows for a long life. Furthermore, since many rollers 130 can be arranged in a small space and locking in both forward and reverse directions can be achieved with one roller 130, it is possible to reduce the size and transmit high torque.

[0037] On the other hand, when the selectable clutch 100 is switched from the locked state to the free state, the drive rod 165 is driven from the locked position toward the free position to rotate the selector 150 in the counter-locking direction. 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 a load acts in a direction that moves the roller 130 toward the pocket portion 125 when the roller holding surface 126 of the pocket portion 125 and the roller holding surface 116 of the support groove portion 115 sandwich the roller 130. This makes it possible to easily rotate the selector 150 with a small force even if torque remains, and also makes it possible to easily release the locked state by disengaging the roller holding surface 151 of the selector 150 from the roller 130, thereby disengaging the roller 130 from the support groove portion 115.

[0038] In the above embodiment, the selector drive mechanism 105 is described as having a so-called linear actuator as its drive source. However, the selector drive mechanism 105 may have a rotary actuator as its drive source as shown in FIG. 7, or may use a worm gear mechanism as shown in FIG. 8.

[0039] A clutch mechanism 101 in the selectable clutch 100 shown in FIG. 7 has the same configuration as that of the selectable clutch 100 shown in FIG. 1, and the same components are given the same reference numerals, and the description thereof will be omitted.

[0040] The selector drive mechanism 105 in the selectable clutch 100 shown in Figure 7 comprises a rotary actuator 160 having a drive shaft 161 that can be driven in both forward and reverse directions, a pivot arm 162 provided on the drive shaft 161, a drive rod 165 having one end connected to the pivot arm 162 and the other end connected to a bearing portion 155 provided on the outer circumferential surface of the selector 150, and capable of reciprocating in one direction between a free position that sets 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 so as to be elastically deformable in the compression direction when the drive rod 165 is moved toward the locked position. In this embodiment, the standby spring 170 is made of a coil spring, and the drive rod 165 is inserted therethrough. Furthermore, the actuator 160 has a lock position maintaining function that fixes the drive rod 165 to the locked position to maintain the position of the selector 150 when the selectable clutch 100 is placed in the locked state. This reliably prevents the selector 150 from accidentally rotating due to vibration or the like, and enables the lock state to be maintained.

[0041] In this selectable clutch 100, when the selectable clutch 100 is switched from a free state to a locked state, the drive shaft 161 is rotated in the forward direction to rotate the pivot arm 162, thereby driving the drive rod 165 toward the locked position. At this time, if the support groove portion 115 of the inner ring 110 and the pocket portion 125 of the outer ring 120 are not in phase with each other, 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 lock standby state. When the phases of support groove portion 115 and pocket portion 125 are aligned, the biasing force of spring mechanism 170 is released, causing selector 150 to rotate in the locking direction, and roller 130 moves radially toward support groove portion 115 due to the action of guide surface 153 of roller accommodating recess 152. When roller 130 moves to support groove portion 115, roller 130 is sandwiched in the circumferential direction between roller holding surface 116 of support groove portion 115 and roller holding surface 126 of pocket portion 125, and roller holding surface 151 of selector 150 abuts against roller 130, causing inner ring 110 and outer ring 120 to mesh with each other.

[0042] On the other hand, when the selectable clutch 100 is switched from the locked state to the free state, the drive shaft 161 is rotated in the reverse direction to rotate the pivot arm 162, thereby driving the drive rod 165 toward the free position. As a result, the selector 150 is rotated in the counter-locking direction to disengage the roller holding surface 151 of the selector 150 from the roller 130, thereby disengaging the roller 130 from the support groove portion 115 and releasing the locked state.

[0043] 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 given the same symbols and will not be described. The selector 150 has worm teeth 157 formed on its outer circumferential surface and is configured to function as a worm wheel.

[0044] As also shown in FIG. 9, the selector drive mechanism 105 in the selectable clutch shown in FIG. 8 comprises an actuator 160, a drive rod 165 that is driven by the actuator 160 to be able to rotate in both forward and reverse directions, a worm 163 that is slidably provided on the drive rod 165 and meshes with the worm teeth 157 of the selector 150, a spring receiving member 166 that is provided on the drive rod 165 at one end side of the worm 163, and a standby spring 170 that is provided on one end side of the spring receiving member 166 with the drive rod 165 inserted therethrough. In this embodiment, the actuator 160 has a locked position maintaining function that maintains the rotational torque and the position of the selector 150 when the selectable clutch 100 is locked. This reliably prevents the selector 150 from rotating unexpectedly due to vibration or the like, and enables the locking state to be maintained. The locked position maintaining function may be realized by configuring the worm gear mechanism so that a self-locking phenomenon occurs.

[0045] In this embodiment, in the free state, the other end of the worm 163 abuts against one of the position regulating portions 124, and when the worm 163 moves so as to elastically deform the standby spring 170 in the compression direction, one end of the spring receiving member 166 abuts against the other position regulating portion 124, thereby regulating the movable range of the worm 163.

[0046] In this selectable clutch, when the selectable clutch is switched from a free state to a locked state, the drive rod 165 is rotationally driven in the forward direction to rotate the worm 163, thereby rotating the selector 150 in the locked direction. At this time, if the support groove portion 115 of the inner ring 110 and the pocket portion 125 of the outer ring 120 are not in phase with each other, as shown in Fig. 10A, the rotation of the selector 150 is prevented, and the worm 163 and the spring receiving 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. 10B, when the phases of the support groove portion 115 and the pocket portion 125 are aligned, the biasing force of the standby spring 170 is released, so that the worm 163 and the spring receiving member 166 move to the free position side and the selector 150 rotates in the locking direction, and the roller 130 moves radially toward the support groove portion 115 due to the action of the guide surface 153 of the roller accommodating recess 152. When the roller 130 moves to the support groove portion 115, the roller 130 is sandwiched in the circumferential direction between the roller holding surface 116 of the support groove portion 115 and the roller holding surface 126 of the pocket portion 125, and the roller holding surface 151 of the selector 150 comes into contact with the roller 130, so that the inner ring 110 and the outer ring 120 mesh with each other.

[0047] On the other hand, when the selectable clutch is switched 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-locked direction. This causes the roller holding surface 151 of the selector 150 to disengage from the roller 130. As a result, the roller 130 is released from the support groove 115 by the load toward the pocket 125 side received from the roller holding surface 126 of the pocket 125 and the roller support surface 116 of the support groove 115, and the biasing force of the elastic member 140, thereby enabling the lock state to be released.

[0048] In each of the above embodiments, the standby spring is provided in the selector drive mechanism. However, the standby spring may be provided in the clutch mechanism. 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 that order, one behind the other in the axial direction. The clutch mechanism 101 has basically the same configuration as those in the above-described embodiments, and the same components as those in the above-described embodiments are denoted by the same reference numerals, and description thereof will be omitted.

[0049] One surface of the selector 150 has a plurality of standby spring arrangement grooves 154 that are formed concentrically with the rotation axis C and extend in the circumferential direction. The standby spring arrangement grooves 154 are formed to be aligned at predetermined intervals in the circumferential direction at positions radially outward from the roller accommodating recesses 152. A coil-shaped standby spring 170 is arranged in the standby spring arrangement groove 154, and a pin member 171 is arranged at one circumferential end (the end on the clockwise side in FIGS. 11 and 12). The pin member 171 is fixed to a rotating plate 185. In addition, 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 into each guide groove 158.

[0050] The rotating plate 185 has a pin member insertion groove 186 extending in the circumferential direction, through which a connecting pin member 187 is slidably inserted, formed in correspondence with the guide groove 158 of the selector 150 . The clutch mechanism 101 is provided with a locked position holding mechanism 190 for holding the selector 150 in the locked position when the selectable clutch is placed in a locked state.

[0051] The lock position retention mechanism 190 comprises a plunger 191 having a plunger hole that opens radially outward, a biasing means 193 that is housed in the plunger hole and biases 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 accommodated in a plunger accommodating hole formed to extend radially from one guide groove portion 158 of the rotating plate 185 and open to the outer circumferential surface of the rotating plate 185, and is disposed so that its tip abuts on the radially inner peripheral surface of the pin member insertion groove portion 186 by fixing the spring receiving portion 194 to the rotating plate 185. The plunger 191 has a tip portion exposed in the pin member insertion groove portion 186 formed in a conical shape, and when the selector 150 is rotated in the locking direction, it presses the connecting pin member 187, thereby moving in a direction that compresses the biasing means 193 due to the action of the tapered surface.

[0052] As shown in FIG. 13, when the selectable clutch is held in a free state, the plunger 191 is positioned on the locking direction side (counterclockwise direction in FIG. 13) with respect to the connecting pin member 187. When the selector 150 rotates in the locking direction with the support groove portion 115 of the inner ring 110 and the pocket portion 125 of the outer ring 120 in phase with each other, the plunger 191 moves radially outward so as to ride on the connecting pin member 187, as shown in FIG. 14A. Thereafter, when the selectable clutch is set in a locked state, the plunger 191 rides over the connecting pin member 187 and moves in the counter-locking direction (clockwise direction) with respect to the connecting pin member 187, as shown in FIG. 14B. This can reliably prevent the selector 150 from accidentally rotating in the counter-locking direction due to vibration or the like, and can mechanically maintain the locked state.

[0053] In this clutch mechanism 101, when the selector 150 is rotated in the locking direction to switch the selectable clutch from a free state to a 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 prevented, while the pin member 171 presses the standby spring 170 in a direction to compress it as the rotating plate rotates, and the sectorable clutch maintains a 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, whereby the roller 130 is held by the support groove 115, the pocket 125, and the selector 150, and the inner ring 110 and the outer ring 120 mesh with each other.

[0054] The selector drive mechanism may be either a linear or rotary actuator, or a worm gear selector drive mechanism, as in the selectable clutch of the above embodiment. Alternatively, the selector drive mechanism may be directly driven by a suitable gear mechanism. In addition, the selectable clutch may be configured to have a lock position maintaining function by using an actuator having a position maintaining function, in which case the clutch mechanism does not have to have a lock position maintaining mechanism.

[0055] Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design modifications can be made without departing from the present invention described in the claims. For example, in each of the above embodiments, a configuration in which the outer ring is fixed and the inner ring is rotated has been described, but a configuration in which the inner ring is fixed and the outer ring is rotated, or a configuration in which both the inner ring and the outer ring rotate, may also be used. In addition, in each of the above embodiments, a configuration has been described in which a support groove portion is formed on the outer peripheral surface of the inner ring, a pocket portion is formed on the inner peripheral surface of the outer ring, and an elastic member is arranged to urge the rollers radially outward. However, a configuration may also be used in which a support groove portion is formed on the inner peripheral surface of the outer ring, a pocket portion is formed on the outer peripheral surface of the inner ring, and an elastic member is arranged to urge the rollers radially inward. Furthermore, in each of the above embodiments, a configuration has been described in which a common elastic member is used for a plurality of rollers, but a configuration may also be used in which a plurality of elastic members are provided corresponding to each of the plurality of rollers. Furthermore, in each of the above embodiments, a selectable clutch is described that is configured to be switchable between two operating modes, a bidirectional free state and a bidirectional locked state. However, by arranging rollers so as to be supported by each of two adjacent support groove portions and providing first and second pocket portions corresponding to each of the two rollers, and further configuring a selector so as to enable radial movement of either or both of the two rollers, the clutch may be configured to be switchable between three to four operating modes including a one-way locked state. [Industrial Applicability]

[0056] The selectable clutch according to the present invention is extremely useful, for example, in constructing a parking lock system for a vehicle. That is, the selectable clutch according to the present invention will not be released from a locked state unless the roller is released from the hold of the selector, so that even if torque is input due to the condition of the road surface on which the vehicle is parked or for other reasons, the locked state will not be released and the vehicle can be maintained in a stopped state. In addition, because the locked state is released when the selector is disengaged from the roller, it is possible to easily release the locked state even if torque is acting on the inner or outer wheel due to a torque load caused by, for example, a slope. [Explanation of symbols]

[0057] 100 ··· Selectable clutch 101 Clutch mechanism 105 Selector drive mechanism 110... Inner circle 111 Small diameter cylindrical portion 112 Large diameter cylindrical portion 115... Support groove 116 Roller retaining surface 120 Outer ring 121 ... Base part 122 ··· Supporting wall part 123 Mounting part 124 ... Position regulation part 125 ··· Pocket section 126 Roller retaining surface 127 Pin member 130 Laura 131 Spring mounting groove 140 Elastic member 150 ··· Selector 151 Roller retaining surface 152 ... Roller receiving recess 153 Guide surface 154 .... Standby spring arrangement groove 155...Bearing section 156 Rotation restriction groove 157 Worm teeth 158 Guide groove 160 ··· Actuator 161 Drive shaft 162 ··· Rotating arm 163 ··· Warm 165 Drive rod 166 Spring receiving member 170 ··· Standby spring 171 Pin member 180 ··· Stop plate 185 Rotating plate 186 Pin member insertion groove portion 187 Connecting pin member 190 Lock position retention mechanism 191 ··· Plunger 193 .... Actuating means 194 Spring receiving part C...Rotation axis center

Claims

1. A selectable clutch comprising a cylindrical inner ring and a cylindrical outer ring arranged coaxially and relatively rotatably, a plurality of rollers arranged between the inner ring and the outer ring, and an elastic member that biases the rollers in a radial direction, a pocket portion configured to be able to accommodate the roller and having a roller retaining surface inclined with respect to the circumferential direction is formed on one of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, and a support groove portion having a roller retaining surface inclined with respect to the circumferential direction is formed on the other of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, The elastic member is provided to bias the roller toward the pocket portion, a selector arranged axially ahead of and behind one of the inner and outer rings in which the pocket portion is formed, so as to be rotatable independently of the inner and outer rings, the selector having a roller holding surface that abuts against the roller when the roller is supported in the support groove portion, and configured to be switchable between a free state that permits relative rotation between the inner and outer rings and a locked state that prohibits relative rotation between the inner and outer rings by moving the roller in a radial direction, a roller holding surface of the pocket portion and a roller holding surface of the support groove portion are formed at an inclination angle such that, when the roller is sandwiched, a load acts in a direction that moves the roller toward the pocket portion, A selectable clutch characterized in that, in a locked state, the roller is held by a roller holding surface of the support groove, a roller holding surface of the pocket, and a roller holding surface of the selector.

2. 2. The selectable clutch according to claim 1, wherein the pocket portion is formed on an inner peripheral surface of the outer ring, and the support groove portion is formed on an outer peripheral surface of the inner ring.

3. the selector has a roller accommodating recess configured to be able to accommodate the roller when the roller is accommodated in the pocket portion and the selectable clutch is in a free state, 2. The selectable clutch according to claim 1, wherein the roller accommodating recess has a guide surface configured to move the roller radially toward the support groove as the selector rotates.

4. a pin member extending in an axial direction is provided on one of the inner ring and the outer ring on which the pocket portion is formed, 2. The selectable clutch according to claim 1, wherein the selector is provided with a rotation restricting groove into which the pin member is slidably inserted, the rotation restricting groove restricting a movable range of the selector.

5. 2. The selectable clutch according to claim 1, wherein an opening edge of said support groove is formed into a C-chamfered shape or an R-chamfered shape.

6. 2. The selectable clutch according to claim 1, further comprising a standby spring that is provided so as to be elastically deformable in a compression direction when the selector is rotated in the locking direction.

7. a selector drive mechanism that rotates the selector independently of the inner ring and the outer ring, the selector drive mechanism includes a drive rod connected to the selector and reciprocatable between a free position in which the dog clutch is in a free state and a locked position in which the dog clutch is held in a locked state, The standby spring is configured by a coil spring through which the drive rod is inserted, 7. The selectable clutch according to claim 6, further comprising a position restricting portion that restricts a movable range of the drive rod.

8. 2. The selectable clutch according to claim 1, further comprising a lock position maintaining function for maintaining the position of the selector when the selectable clutch is brought into a locked state.

9. 2. The selectable clutch according to claim 1, wherein said elastic member is common to each of said plurality of rollers.

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