Reverse input blocking clutch

Abstract

To achieve a structure capable of switching between validity and invalidity of a reverse input blocking function of not transmitting torque reversely input to an output member to an input member.SOLUTION: In the first state in which the switching member 6 is in the first axial position, the pressing surface is allowed to be pressed against the pressed surface 7 by the suppressing portion 51 not suppressing the suppressed portion 46 provided on the engaging element 5 from the outer side in the radial direction, and in the second state in which the switching member 6 is in the second axial position, the pressing surface is prevented from being pressed against the pressed surface 7 by the suppressing portion 51 suppressing the suppressed portion 46 from the outer side in the radial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a reverse input disconnecting clutch that transmits rotational torque input to an input member to an output member, while completely blocking rotational torque that is reversely input to the output member and not transmitting it to the input member, or that transmits only a portion of the torque to the input member and blocks the remainder. [Background technology]

[0002] A reverse input cut-off clutch has an input member connected to an input side mechanism such as a drive source, and an output member connected to an output side mechanism such as a reduction mechanism, and has the function of transmitting the rotational torque input to the input member to the output member, while completely cutting off the rotational torque input in reverse to the output member, so that it is not transmitted to the input member, or by transmitting only a portion of it to the input member and cutting off the remainder.

[0003] There are two types of reverse input cutoff clutches: a lock type reverse input cutoff clutch that has a mechanism that prevents the output member from rotating when rotational torque is input in reverse to the output member, and a free type reverse input cutoff clutch that has a mechanism that causes the output member to spin freely when rotational torque is input to the output member.

[0004] International Publication No. 2019 / 026794 describes a locking reverse input disconnection clutch that includes a pressed member, an input member, an output member, and an engaging element. In this reverse input disconnection clutch, when rotational torque is input to the input member, the input-side engaging portion of the input member engages with the input-side engaged portion of the engaging element, causing the engaging element to move radially inward, and the output-side engaged portion of the engaging element engages with the output-side engaging portion of the output member, thereby transmitting the rotational torque input to the input member to the output member. On the other hand, when rotational torque is reversely input to the output member, the output-side engaging portion engages with the output-side engaged portion, causing the engaging element to move radially outward, causing the pressing surface of the engaging element to be pressed against the pressed surface of the pressed member, thereby frictionally engaging the pressing surface with the pressed surface.

[0005] To completely block the rotational torque reversely input to the output member and prevent it from being transmitted to the input member, the output member is locked by sandwiching the engaging element between the output-side engaging portion and the pressed member so that the pressing surface of the engaging element does not slide against the pressed surface.To transmit only a portion of the rotational torque reversely input to the output member to the input member and block the remainder, the output member is partially locked by sandwiching the engaging element between the output-side engaging portion and the pressed member so that the pressing surface of the engaging element slides against the pressed surface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2019 / 026794 Brochure Summary of the Invention [Problem to be solved by the invention]

[0007] In a mechanical device incorporating a reverse input cut-off clutch, for example, if a failure occurs in the drive source connected to the input member and torque can no longer be input from the input member to the reverse input cut-off clutch, it may become necessary to change the position, posture, etc. of the driven member connected to the output member in order to ensure safety, etc.

[0008] However, regardless of the direction of rotation, the torque input to the output member is not transmitted to the input member, or only a portion of it is transmitted to the input member. In other words, even if you try to rotate the output member, the rotation of the output member will be locked or semi-locked, which may result in problems such as the position or attitude of the driven device not being able to be changed, or even if it is possible to change it, it will not be easy to do so.

[0009] The present disclosure aims to realize a reverse input blocking clutch structure that can switch between enabling and disabling a reverse input blocking function that prevents torque reversely input to an output member from being transmitted to an input member. [Means for solving the problem]

[0010] The reverse input disconnecting clutch of the first aspect of the present disclosure includes: a pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion disposed radially inside the pressed surface and disposed coaxially with the pressed surface; an output member having an output side engaging portion disposed radially inward of the input side engaging portion and disposed coaxially with the pressed surface; an engaging element having a pressing surface opposing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and arranged to be movable in a radial direction; When a rotational torque is input to the input member, the engaging element moves away from the pressed surface based on the engagement of the input side engaging portion with the input side engaged portion, and engages the output side engaged portion with the output side engaging portion, thereby transmitting the rotational torque input to the input member to the output member. Conversely, when a rotational torque is input in the reverse direction to the output member, the output side engaging portion engages with the output side engaged portion, and presses the pressing surface against the pressed surface, causing the pressing surface to frictionally engage with the pressed surface.

[0011] The reverse input disconnect clutch of the first aspect of the present disclosure further includes a switching member having a suppressing portion and arranged to be movable in the axial direction. The engaging element also has a suppressed portion engageable with the suppressing portion.

[0012] In a first state in which the switching member is in a first axial position, the restraining portion does not restrain the restrained portion from the radial outside, thereby allowing the pressing surface to be pressed against the restrained surface, and in a second state in which the switching member is in a second axial position, the restraining portion restrains the restrained portion from the radial outside, thereby preventing the pressing surface from being pressed against the restrained surface.

[0013] In the second state, the engagement element transmits torque between the input member and the output member regardless of the direction of torque transmission between the input member and the output member.

[0014] In the reverse input disconnection clutch of the second aspect of the present disclosure, in the reverse input disconnection clutch of the first aspect of the present disclosure, at least one of the restraining portion and the restrained portion has a guide surface inclined with respect to the axial direction that moves the engaging element radially inward based on sliding between the restraining portion and a part of the other of the restrained portion when the switching member moves from the first axial position to the second axial position.

[0015] A reverse input disconnection clutch of a third aspect of the present disclosure is the reverse input disconnection clutch of the second aspect of the present disclosure, wherein the guide surface is an outer diameter side guide surface provided on a radially inner surface of the pressing portion.

[0016] A fourth aspect of the reverse input disconnection clutch of the present disclosure is the reverse input disconnection clutch of the third aspect of the present disclosure, wherein the guide surface is an inner diameter side guide surface that is provided on the restrained portion and is capable of surface contact with the outer diameter side guide surface.

[0017] A reverse input disconnection clutch of a fifth aspect of the present disclosure is a reverse input disconnection clutch of any of the first to fourth aspects of the present disclosure, which is provided with an elastic member for the switching member that applies elastic force to the switching member in a direction from the second axial position side toward the first axial position side.

[0018] A sixth aspect of the present disclosure is a reverse input disconnection clutch in the fifth aspect of the present disclosure, which is provided with a movement mechanism that moves the switching member from the first axial position to the second axial position against the elastic force of the elastic member for the switching member.

[0019] In a reverse input disconnection clutch of a seventh aspect of the present disclosure, in the reverse input disconnection clutch of the sixth aspect of the present disclosure, the moving mechanism includes a pressing member that presses the switching member in the axial direction, thereby moving the switching member from the first axial position to the second axial position.

[0020] In a reverse input cutoff clutch of an eighth aspect of the present disclosure, in the reverse input cutoff clutch of the seventh aspect of the present disclosure, the pressing member is configured by a cam rod that is rotatably supported relative to the pressed member and has a cam surface that presses the switching member in the axial direction as the rotation occurs.

[0021] In a reverse input cutoff clutch of a ninth aspect of the present disclosure, in the reverse input cutoff clutch of the seventh aspect of the present disclosure, the pressing member is configured by a pressing rod that is supported so as to be able to move axially relative to the pressed member, and that presses the switching member in the axial direction as it moves axially.

[0022] In a reverse input disconnection clutch of a tenth aspect of the present disclosure, in a reverse input disconnection clutch of any one of the first to ninth aspects of the present disclosure, the switching member is supported on the output member so as to be movable in the axial direction.

[0023] In the reverse input disconnection clutch of the eleventh aspect of the present disclosure, in the reverse input disconnection clutch of any one of the first to tenth aspects of the present disclosure, the switching member is circumferentially engaged with the output member so as to prevent relative rotation with the output member.

[0024] In the reverse input disconnection clutch of the 12th aspect of the present disclosure, in a reverse input disconnection clutch of any one of the first to tenth aspects of the present disclosure, the suppression portion of the switching member is engaged with the engaging element in the circumferential direction so as to prevent relative rotation between the switching member and the engaging element.

[0025] In the reverse input disconnection clutch of the 13th aspect of the present disclosure, in the reverse input disconnection clutch of the 12th aspect of the present disclosure, the engaging element has a radial recess that recesses radially inward at the widthwise middle portion of the radially outer end, and by engaging the retaining portion with the radial recess, relative rotation between the switching member and the engaging element is prevented.

[0026] In one aspect of the reverse input disconnection clutch of the present disclosure, in a reverse input disconnection clutch of any one of the first to thirteenth aspects of the present disclosure, the engaging element is composed of multiple engaging elements arranged at different positions in the circumferential direction. [Effects of the Invention]

[0027] According to the reverse input cutoff clutch of one aspect of the present disclosure, it is possible to switch between enabling and disabling the reverse input cutoff function that does not transmit torque reversely input to the output member to the input member. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a cross-sectional view of a reverse input cutoff clutch according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged view of the upper part of FIG. [Figure 3] FIG. 3 is an exploded perspective view of the reverse input cutoff clutch of the first example, as viewed from one axial side. [Figure 4] FIG. 4 is an exploded perspective view of the reverse input cutoff clutch of the first example, as viewed from the other axial side. [Figure 5] FIG. 5 is a perspective view of a part of the reverse input cutoff clutch of the first example, as viewed from one axial side. [Figure 6] FIG. 6 is a cross-sectional view taken along the line AA in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along the line AA in FIG. 1, showing a state in which a rotational torque is input to the input member, with the biasing member omitted. [Figure 8] 8 is a cross-sectional view taken along the line AA in FIG. 1, showing a state in which a rotational torque is reversely input to the output member, with the biasing member omitted. [Figure 9] 9(a) and 9(b) are schematic diagrams showing a state in which the reverse input cutoff clutch of the first example is switched from the first state to the second state. [Figure 10] FIG. 10 is a cross-sectional view of a reverse input disconnecting clutch according to a second example of an embodiment of the present disclosure. [Figure 11] 11(a) and 11(b) are schematic diagrams showing a state in which the reverse input cutoff clutch of the second example is switched from the first state to the second state. [Figure 12] FIG. 12 is a view corresponding to FIG. 6, illustrating only the engagement element and the retaining portion of the switching member in the reverse input cutoff clutch according to the third example of the embodiment of the present disclosure. [Figure 13] FIG. 13 is a schematic diagram of an engaging portion between a restrained portion of an engaging element and a restraining portion of a switching member, viewed from the width direction of the engaging element, in a reverse input cutoff clutch according to a fourth example of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0029] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 9(b).

[0030] In the following description, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the reverse input disconnection clutch 1. The axial direction, radial direction, and circumferential direction of the reverse input disconnection clutch 1 coincide with the axial direction, radial direction, and circumferential direction of the pressed surface 7 of the pressed member 2, the input member 3, and the output member 4, respectively. One axial side is the input member 3 side (the right side in FIG. 1), and the other axial side is the output member 4 side (the left side in FIG. 1).

[0031] The direction of the pressing surface 43 of the engaging element 5 toward or away from the pressed surface 7 is defined as the first direction (the up-and-down direction in Fig. 1 and Figs. 6 to 8), and the direction perpendicular to both the axial direction of the pressed surface 7 and the first direction is defined as the second direction (the front-to-back direction in Fig. 1, the left-to-right direction in Figs. 6 to 8). With respect to the engaging element 5, the direction coinciding with the first direction is defined as its radial direction (the direction indicated by arrow α in Fig. 6), and the direction coinciding with the second direction is defined as its width direction (the direction indicated by arrow β in Fig. 6).

[0032] The reverse input cutoff clutch 1 includes a pressed member 2, an input member 3, an output member 4, and an engaging element 5.

[0033] The reverse input cutoff clutch 1 further includes a switching member 6 that can switch between enabling and disabling the reverse input cutoff function.

[0034] When the reverse input blocking function of the reverse input blocking clutch 1 is active, when rotational torque is input to the input member 3, the input-side engaged portion 44 of the engaging element 5 engages with the input-side engaging portion 21 of the input member 3, causing the engaging element 5 to move radially inward away from the pressed surface 7 of the pressed member 2 and engage the output-side engaged portion 45 with the output-side engaging portion 30 of the output member 4, thereby transmitting the rotational torque input to the input member 3 to the output member 4. In contrast, when rotational torque is reversely input to the output member 4, the output-side engaged portion 30 engages with the output-side engaged portion 45, causing the pressing surface 43 to be pressed against the pressed surface 7, causing the pressing surface 43 to be frictionally engaged with the pressed surface 7. As a result, the rotational torque reversely input to the output member 4 is either completely blocked and not transmitted to the input member 3, or only a portion of the torque is transmitted to the input member 3 and the remainder is blocked.

[0035] When the reverse input blocking function of the reverse input blocking clutch 1 is disabled, the engaging element 5 transmits torque between the input member 3 and the output member 4 regardless of the direction of torque transmission between the input member 3 and the output member 4.

[0036] The materials for the pressed member 2, input member 3, output member 4, engaging element 5, and switching member 6 are not particularly limited as long as they can ensure the necessary mechanical properties such as strength. For example, these materials can be metals such as iron alloys, copper alloys, and aluminum alloys, as well as synthetic resins mixed with reinforcing fibers as needed. Furthermore, the pressed member 2, input member 3, output member 4, and engaging element 5 can be made of the same material or different materials.

[0037] When the reverse input blocking function of the reverse input blocking clutch 1 is active, lubricant can be applied to the contacting portions of the pressed member 2, input member 3, output member 4, and engaging member 5, as long as the lubricant does not impede the function. Alternatively, at least one of the pressed member 2, input member 3, output member 4, and engaging member 5 can be made of oil-impregnated metal or oil-impregnated resin.

[0038] The pressed member 2 has a pressed surface 7 on its inner circumferential surface. The pressed surface 7 faces the pressing surface 43 of the engaging element 5, and has the function of preventing or restricting rotation of the engaging element 5 by frictionally engaging with the pressing surface 43 of the engaging element 5 when the engaging element 5 moves in a direction approaching the pressed surface 7 in the first direction. The input-side engaging portion 21 of the input member 3, the output-side engaging portion 30 of the output member 4, and the engaging element 5 are arranged radially inward of the pressed surface 7.

[0039] The pressed member 2 is supported and fixed to a fixed part such as a housing that does not rotate even when in use, and its rotation is restricted, or it is constituted by the fixed part. In other words, the pressed member 2 does not rotate even when in use. In this example, the pressed member 2 is supported and fixed to the fixed part, and its rotation is restricted.

[0040] The pressed surface 7 has an annular shape when viewed in the axial direction. The pressed surface 7 can be configured as a cylindrical surface whose inner diameter does not change in the axial direction, or as a non-cylindrical surface whose inner diameter changes in the axial direction. In this example, the pressed surface 7 is configured as a cylindrical surface whose inner diameter does not change in the axial direction.

[0041] The structure of the pressed member 2 is not limited as long as it has a pressed surface 7 on its inner circumferential surface. The pressed member 2 can be formed of a single part, or can be formed by combining multiple parts. The structure for arranging, supporting, and functioning the input member 3 and / or the output member 4 can be provided in the fixed part separately from the pressed member 2, or can be provided in the pressed member 2.

[0042] In this example, the pressed member 2 includes an input element 8 and an output element 9.

[0043] Input element 8 has a stepped cylindrical shape. Specifically, input element 8 includes a small-diameter cylindrical portion 10 on one axial side, a large-diameter cylindrical portion 11 on the other axial side, and a connecting portion 12 connecting small-diameter cylindrical portion 10 and large-diameter cylindrical portion 11. In this example, the inner peripheral surface of large-diameter cylindrical portion 11 forms pressed surface 7.

[0044] The input side element 8 has an inward flange portion 13 that protrudes radially inward at one axial end of the small diameter cylindrical portion 10, and has outward flange portions 14 that protrude radially outward at multiple locations circumferentially at the other axial end of the large diameter cylindrical portion 11.

[0045] The output element 9 has a stepped cylindrical shape. Specifically, the output element 9 includes a large-diameter cylindrical portion 15 on one axial side, a small-diameter cylindrical portion 16 on the other axial side, and a connecting portion 17 connecting the large-diameter cylindrical portion 15 and the small-diameter cylindrical portion 16. The output element 9 also includes an inward flange portion 18 that protrudes radially inward at the end of the small-diameter cylindrical portion 16 on the other axial side, and through-holes 19 that penetrate the large-diameter cylindrical portion 15 in the axial direction at multiple locations around the circumference.

[0046] In this example, the input element 8 and the output element 9 are fitted together (spigot fitting) without any rattle, so that the input element 8 and the output element 9 are positioned radially, and then a bolt 20 is inserted through a mounting hole provided so as to axially penetrate the outward flange portion 14 of the input element 8 and screwed into a threaded hole opening on one axial side surface of the large-diameter cylindrical portion 15 of the output element 9, thereby forming the pressed member 2. The pressed member 2 is supported and fixed to the fixed portion by screwing a bolt inserted through a through hole 19 of the output element 9 into a threaded hole provided in the fixed portion.

[0047] The input member 3 has an input-side engagement portion 21 arranged radially inside the pressed surface 7, and is arranged coaxially with the pressed surface 7. The input member 3 is connected to an input-side mechanism such as a drive source, and rotational torque is input to the input member 3. The input member 3 may be configured as an output shaft of the input-side mechanism, or the input member 3 may be configured as a separate member from the output shaft and fixed coaxially to the output shaft. Additionally, the input shaft portion 22 provided on the input member 3 may be rotatably supported relative to the fixed portion.

[0048] In this example, the input member 3 is configured as a separate member from the output shaft and includes a cylindrical input shaft portion 22, which is coaxially fixed to the tip end of the output shaft of the input-side mechanism. In this example, the input member 3 further includes an input flange portion 23 that extends radially outward from the other axial end of the input shaft portion 22.

[0049] The input-side engaging portion 21 is provided at a portion radially outwardly displaced from the rotation center O of the input member 3, and has a portion that engages with the input-side engaged portion 44 of the engager 5. The input-side engaging portion 21 is configured so that its radially inner surface 24 engages, specifically comes into contact with, the radially inner surface 47 of the input-side engaged portion 44 as the input member 3 or the engager 5 rotates. In this example, the input-side engaging portion 21 is provided so as to protrude toward the other axial side from a portion of the end face on the other axial side of the input flange portion 23 that is radially outwardly displaced from the rotation center axis O.

[0050] The shape of the input side engaging portion 21 is not limited as long as it is configured to engage with the input side engaged portion 44 of the engaging element 5 .

[0051] For example, the input-side engaging portion 21 may have an end face shape that is symmetrical with respect to the circumferential direction, or may have an end face shape that is asymmetrical with respect to the circumferential direction. In this example, the input-side engaging portion 21 has an end face shape that is symmetrical with respect to the circumferential direction.

[0052] For example, the input-side engaging portion 21 may have an end face shape that is partially annular, trapezoidal, or similar, with its circumferential width increasing radially outward when viewed from the axial direction. In this example, the circumferential middle portion of the radially inner surface 24 of the input-side engaging portion 21 is formed by a flat surface that is perpendicular to the line connecting the rotation axis O and the center of the input-side engaging portion 21 when viewed from the axial direction, and the circumferential side portions are formed by partially cylindrical convex surfaces that slope radially outward toward both circumferential sides. The radially outer surface 25 of the input-side engaging portion 21 is formed by a partially cylindrical convex surface centered on the rotation axis O.

[0053] The number of input side engaging portions 21 is determined according to the number of engaging elements 5, and when the engaging elements 5 are composed of a plurality of engaging elements 5, the input side engaging portion 21 is also composed of a plurality of input side engaging portions 21. In this example, the engaging elements 5 are composed of two engaging elements 5. Therefore, the input side engaging portion 21 is composed of two input side engaging portions 21 to match the number of engaging elements 5. The two input side engaging portions 21 are arranged at two radially opposite positions on the side surface on the other axial side of the input flange portion 23, and are spaced apart from each other in the radial direction of the input member 3.

[0054] The input member 3 is rotatably supported by the fixed portion or the pressed member 2 supported and fixed to the fixed portion. In this example, the input member 3 is rotatably supported radially inside the input element 8 of the pressed member 2 by a radial rolling bearing 26. The radial rolling bearing 26 includes an outer ring 27, an inner ring 28, and a plurality of rolling elements 29.

[0055] The outer ring 27 is fitted securely into the small-diameter cylindrical portion 10, and one end face of the outer ring 27 in the axial direction abuts against the side face of the inward flange portion 13 on the other axial side.

[0056] The inner ring 28 is fitted onto the other axial end of the input shaft portion 22 without any rattle, and the other axial end face thereof abuts against the side face of the input flange portion 23 on one axial side.

[0057] A plurality of rolling elements 29 are arranged to roll freely between the outer ring 27 and the inner ring 28. Each of the rolling elements 29 is made up of a ball, a cylindrical roller, or a tapered roller. In this example, each of the rolling elements 29 is made up of a ball.

[0058] The output member 4 has an output-side engaging portion 30 that is arranged radially inward of the input-side engaging portion 21 on the radial inside of the pressed surface 7, and is arranged coaxially with the pressed surface 7. The output member 4 is also arranged coaxially with the input member 3 on the radial inside of the pressed surface 7.

[0059] The output member 4 is connected to an output mechanism such as a reduction gear mechanism, and is configured to output rotational torque to the output mechanism as it rotates. The output member 4 may be configured as an input shaft of the output mechanism, or the output member 4 may be configured as a separate member from the input shaft and fixed coaxially to the input shaft.

[0060] The output side engaging portion 30 has a portion that can engage with the output side engaged portion 45 of the engaging element 5, and the engageable portion is located radially inward of the input side engaging portion 21 and radially outward from the central axis O of the output member 4, at a position where it can engage with the output side engaged portion 45 of the engaging element 5. The output side engaging portion 30 is configured so that the engageable portion engages with, or more specifically comes into contact with, the output side engaged portion 45 as the output member 4 or the engaging element 5 rotates.

[0061] The shape of the output side engaging portion 30 is not limited as long as it has a portion that can engage with the output side engaged portion 45 of the engaging element 5 .

[0062] The output-side engaging portion 30 has a cam function. That is, the distance from the rotational center axis O of the output member 4 to the outer circumferential surface of the output-side engaging portion 30, which is the portion that engages with the output-side engaged portion 45, is not constant in the circumferential direction.

[0063] The number of portions of the output side engaging portion 30 that engage with the output side engaged portions 45 is determined according to the number of engaging elements 5, and when the engaging element 5 is made up of a plurality of engaging elements 5, the output side engaging portion 30 is also configured to have a plurality of the engaging portions. In this example, the output side engaging portion 30 is configured to have portions that engage with two of the output side engaged portions 45, matching the number of engaging elements 5. However, even when the number of engaging elements 5 is one, it is possible to adopt a structure similar to this example.

[0064] The cross-sectional shape of the output side engaging portion 30 when cut along an imaginary plane perpendicular to the rotation center axis O of the output member 4 can be any shape as long as the output side engaging portion 30 has a cam function, and can be, for example, a quadrangle such as a square, rectangle, parallelogram, or trapezoid, an oval, or a shape similar to these.

[0065] 6, the output-side engaging portion 30 has a substantially rectangular cross-sectional shape when cut along an imaginary plane perpendicular to the central axis O of rotation of the output member 4. More specifically, the outer circumferential surface of the output-side engaging portion 30 is composed of two parallel flat surfaces 31 and two partially cylindrical convex surfaces 32.

[0066] In this example, the output-side engaging portion 30 is plane-symmetric with respect to an imaginary plane that passes through the rotational center axis O of the output member 4 and is perpendicular to the two flat surfaces 31. Furthermore, the output-side engaging portion 30 is plane-symmetric with respect to an imaginary plane that passes through the rotational center axis O of the output member 4 and is parallel to the two flat surfaces 31. In other words, the output-side engaging portion 30 has a shape that is two-fold symmetric with respect to the central axis of the output member 4. The output-side engaging portion 30 is disposed radially inward of the two input-side engaging portions 21 and between the output-side engaged portions 45 of the two engagers 5.

[0067] In this example, the output member 4 is configured as a separate member from the input shaft of the output side mechanism, and in addition to the output side engagement portion 30, has an output shaft portion 33, which is fixed coaxially to the input shaft of the output side mechanism.

[0068] The output shaft portion 33 has a stepped cylindrical shape. Specifically, the output shaft portion 33 has, in order from one axial side, a medium diameter portion 34, a large diameter portion 35, and a small diameter portion 36. The medium diameter portion 34 is configured to have a smaller diameter than the large diameter portion 35 but a larger diameter than the small diameter portion 36. The outer circumferential surfaces of the medium diameter portion 34 and the large diameter portion 35 are connected by a step surface 37 facing one axial side. The outer circumferential surfaces of the large diameter portion 35 and the small diameter portion 36 are connected by a step surface 38 facing the other axial side. The output side engaging portion 30 protrudes from the center of the end face on one axial side of the medium diameter portion 34 toward one axial side.

[0069] The output member 4 can be rotatably supported by the pressed member 2 or the fixed portion. In this example, the output member 4 is rotatably supported on the radially inner side of the pressed member 2 by a radial rolling bearing 39. The radial rolling bearing 39 includes an outer ring 40, an inner ring 41, and a plurality of rolling elements 42.

[0070] The outer ring 40 is fitted securely into the small-diameter cylindrical portion 16, and the end face on the other axial side thereof abuts against the side face of the inward flange portion 18 on one axial side.

[0071] The inner ring 41 is fitted onto one axial end of the small diameter portion 36 without any rattle, and the end face on that axial end abuts against the stepped surface 38 .

[0072] A plurality of rolling elements 42 are arranged to roll freely between the outer ring 40 and the inner ring 41. Each of the rolling elements 42 is made up of a ball, a cylindrical roller, or a tapered roller. In this example, each of the rolling elements 42 is made up of a ball.

[0073] The engaging element 5 has a pressing surface 43 facing the pressed surface 7, an input side engaged portion 44 engageable with the input side engaging portion 21, and an output side engaged portion 45 engageable with the output side engaging portion 30, and is arranged so as to be movable in the radial direction (first direction).

[0074] When a rotational torque is input to the input member 3, the engaging element 5 moves radially inward away from the pressed surface 7 based on the engagement of the input side engaging portion 21 with the input side engaged portion 44, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output side engaged portion 45 with the output side engaging portion 30. Conversely, when a rotational torque is input in the reverse direction to the output member 4, the engaging element 5 moves radially outward toward the pressed surface 7 based on the engagement of the output side engaged portion 45 with the output side engaging portion 30, and presses the pressing surface 43 against the pressed surface 7, thereby frictionally engaging the pressing surface 43 with the pressed surface 7.

[0075] In this example, the engaging element 5 has an end face shape similar to a semicircle when viewed from the axial direction, and has a shape that is symmetrical with respect to the width direction.

[0076] The pressing surface 43 is provided on the radially outer surface of the engaging element 5 that faces the pressed surface 7. The pressing surface 43 can be configured from all or part of the radially outer surface of the engaging element 5. The number of pressing surfaces 43 can be any number equal to or greater than one. In this example, the pressing surface 43 is configured from two pressing surfaces 43 provided at two positions on the radially outer surface of the engaging element 5 that are spaced apart from each other in the circumferential direction. Each pressing surface 43 is configured from a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface 7.

[0077] When viewed from the axial direction, the portion of the radially outer surface of the engaging element 5 that is circumferentially deviated from the two pressing surfaces 43 is located radially inward of an imaginary circle that is centered on the rotational center axis O of the input member 3 and that is tangent to the two pressing surfaces 43. In other words, when the two pressing surfaces 43 are in contact with the pressed surface 7, the portion that is circumferentially deviated from the two pressing surfaces 43 does not come into contact with the pressed surface 7.

[0078] The shape and arrangement of the input-side engaged portion 44 are not limited as long as it is configured to be able to engage with the input-side engaging portion 21 as the input member 3 rotates and move the engaging element 5 radially inward and away from the pressed surface 7. The input-side engaged portion 44 is located at the widthwise intermediate portion of the engaging element 5, and is configured by a radial recess provided in a portion of the radial outer surface of the engaging element 5 that is away from the pressing surface 43, an axial through-hole or an axial recess provided in the radial intermediate portion of the engaging element 5, or the like.

[0079] In this example, the input-side engaged portion 44 is provided in a radially intermediate portion of the widthwise center of the engaging element 5. When viewed from the axial direction, the input-side engaged portion 44 has an opening shape similar to an oval that is elongated in the widthwise direction of the engaging element 5, and is configured as a through-hole that passes through a radially intermediate portion of the widthwise center of the engaging element 5 in the axial direction.

[0080] The input-side engaged portion 44 has a size that allows the input-side engaging portion 21 to be loosely inserted therein. Therefore, when the input-side engaging portion 21 is inserted inside the input-side engaged portion 44, there is a gap between the input-side engaging portion 21 and the inner surface of the input-side engaged portion 44 in both the width direction and the radial direction of the engaging element 5. Therefore, the input-side engaging portion 21 can be displaced relative to the input-side engaged portion 44 in the rotational direction of the input member 3, and the input-side engaged portion 44 can be displaced in the radial direction of the engaging element 5 relative to the input-side engaged portion 44. In this example, of the inner surface of the input-side engaged portion 44, a radially inner surface 47 facing radially outward is formed by a flat surface perpendicular to the first direction.

[0081] The shape and arrangement of the output-side engaged portion 45 are not limited as long as it is configured to be able to engage with the output-side engaging portion 30 as the output member 4 rotates, and move the engaging element 5 radially outward so as to approach the pressed surface 7. The output-side engaged portion 45 is located at the middle portion of the engaging element 5 in the width direction, and is configured by the radially inner surface of the engaging element 5, a radial recess provided on the radially inner surface, etc.

[0082] In this example, the output-side engaged portion 45 is provided in the widthwise center of the radially inner surface of the engaging element 5, which is the side surface opposite the pressed surface 7 in the first direction. The engaging element 5 has a flat surface portion 48 on its radially inner surface that is perpendicular to the radial direction of the engaging element 5, and the flat surface portion 48 has two protrusions 49 that protrude radially inward at two positions in the width direction of the engaging element 5. The output-side engaged portion 45 is formed by a portion of the flat surface portion 48 that is located between the two protrusions 49 in the width direction. The widthwise dimension of the output-side engaged portion 45, i.e., the distance between the two protrusions 49, is larger than the widthwise dimension of the flat surface 31 of the output-side engaging portion 30.

[0083] As long as the engaging element 5 has the above-described configuration, it can be configured with one engaging element 5 or with multiple engaging elements 5 arranged at different positions in the circumferential direction. In this example, the engaging element 5 is configured with two engaging elements 5 arranged at positions sandwiching the central axis of the pressed surface 7 from both sides in the radial direction. Each engaging element 5 has the function of an engaging element 5.

[0084] In the reverse input cutoff clutch 1 of this example, the pressing surfaces 43 of the two engaging elements 5 face radially opposite each other, and the flat surface portions 48 face each other, with each engaging element 5 disposed radially inward of the pressed surface 7 so as to be movable in the first direction. Furthermore, the two input-side engaging portions 21 of the input member 3 disposed on one axial side are axially inserted into the input-side engaged portions 44 of the two engaging elements 5, and the output-side engaging portion 30 of the output member 4 disposed on the other axial side is axially inserted between the output-side engaged portions 45 of the two engaging elements 5. In other words, the two engaging elements 5 are disposed so that the output-side engaging portion 30 is sandwiched from both radial sides by the respective output-side engaged portions 45.

[0085] When the two engaging elements 5 are positioned radially inside the pressed surface 7, the inner diameter dimension of the pressed surface 7 and the radial dimension of the engaging elements 5 are regulated so that a gap exists in at least one of the areas between the pressed surface 7 and the pressing surface 43, the area between the output side engaging portion 30 and the output side engaged portion 45, and the area between the tip faces of the convex portions 49.

[0086] Here, the operation of the reverse input cutoff clutch 1 when the reverse input cutoff function is switched to active by the switching member 6 will be described with reference to Figures 7 and 8. Note that Figures 7 and 8 omit the biasing member 74 and exaggerate the radial gaps between the input member 3 and the output member 4 and the two engaging elements 5.

[0087] When a rotational torque is input to the input member 3, the engaging element 5 moves in a direction away from the pressed surface 7, regardless of the rotational direction of the input member 3. Then, the rotational torque input to the input member 3 is transmitted to the output member 4 via the engaging element 5.

[0088] That is, when a rotational torque is input to the input member 3, the input-side engaging portion 21 rotates inside the input-side engaged portion 44 in the rotation direction of the input member 3 (counterclockwise in the example of FIG. 7), as shown in FIG. 7. This reduces the gap between the radially inner surface 24 of the input-side engaging portion 21 and the radially inner surface 47 of the input-side engaged portion 44, and brings the radially inner surface 24 of the input-side engaging portion 21 into contact with the radially inner surface 47 of the input-side engaged portion 44.

[0089] When the input member 3 rotates further from this state, the radially inner surface 24 of the input-side engaging portion 21 presses the radially inner surface 47 of the input-side engaged portion 44 radially inward, and the engaging element 5 moves in a direction away from the pressed surface 7. That is, the engaging element 5 moves radially inward based on engagement with the input member 3, and the output-side engaged portion 45 of the engaging element 5 engages with the output-side engaging portion 30 of the output member 4. In this example, the radially inner surfaces of the two engaging elements 5 approach each other, and the output-side engaged portions 45 of the two engaging elements 5 clamp the output-side engaging portion 30 of the output member 4 from both radial sides.

[0090] More specifically, when the output-side engaged portion 45 of the engaging element 5 engages with the output-side engaging portion 30, the output member 4 rotates so that the flat surface 31 of the output-side engaging portion 30 is parallel to the output-side engaged portion 45 of the engaging element 5, causing the flat surface 31 to abut against the output-side engaged portion 45 without rattle. As a result, the rotational torque input to the input member 3 is transmitted to the output member 4 via the engaging element 5 and is output from the output member 4.

[0091] When a rotational torque is reversely input to the output member 4, the engaging element 5 moves in a direction approaching the pressed surface 7, regardless of the rotational direction of the output member 4. Then, the rotational torque reversely input to the output member 4 is completely blocked and not transmitted to the input member 3, or only a portion of the rotational torque reversely input to the output member 4 is transmitted to the input member 3, with the remainder blocked.

[0092] More specifically, as shown in Fig. 8, the output-side engaging portion 30 rotates relative to the engaging element 5 in the rotation direction of the output member 4 (clockwise in the example of Fig. 8). The output-side engaged portion 45 is pressed radially outward by the connection (corner) between the flat surface 31 and the convex curved surface 32 on the outer circumferential surface of the output-side engaging portion 30, and the engaging element 5 moves in a direction approaching the pressed surface 7.

[0093] That is, the engaging elements 5 move radially outward based on their engagement with the output member 4, and the pressing surfaces 43 of the engaging elements 5 come into contact with the pressed surface 7 and frictionally engage with the pressed surface 7. In this example, the two engaging elements 5 move radially outward, i.e., in directions away from each other, based on their engagement with the output member 4, and the pressing surfaces 43 of the two engaging elements 5 come into contact with the pressed surface 7 and frictionally engage with the pressed surface 7.

[0094] As a result, the rotational torque input back to the output member 4 is either completely blocked and not transmitted to the input member 3, or only a portion of the rotational torque input back to the output member 4 is transmitted to the input member 3 and the remainder is blocked.

[0095] To completely block the rotational torque input in reverse to the output member 4 and prevent it from being transmitted to the input member 3, the engaging element 5 is clamped between the output side engaging portion 30 and the pressed member 2 so that the pressing surface 43 of the engaging element 5 does not slide against the pressed surface 7, thereby locking the output member 4.

[0096] In order to transmit only a portion of the rotational torque input inversely to the output member 4 to the input member 3 and block the remainder, the engaging element 5 is clamped between the output side engaging portion 30 and the pressed member 2 so that the pressing surface 43 of the engaging element 5 slides against the pressed surface 7, thereby semi-locking the output member 4.

[0097] The switching member 6 has a retaining portion 51 and is arranged so as to be movable in the axial direction.

[0098] In the reverse input cut-off clutch 1, in a first state in which the switching member 6 is in a first axial position, the restraining portion 51 does not press the restrained portion 46 provided on the engaging element 5 from the radial outside, thereby allowing the pressing surface 43 to be pressed against the pressed surface 7, and in a second state in which the switching member 6 is in a second axial position, the restraining portion 51 presses the restrained portion 46 from the radial outside, thereby preventing the pressing surface 43 from being pressed against the pressed surface 7.

[0099] The reverse input disconnecting clutch 1 is switched between the first state and the second state by moving the switching member 6 in the axial direction between a first axial position and a second axial position.

[0100] In normal use of the reverse input cutoff clutch 1 after it is installed in the middle of the torque transmission path of a mechanical device and before any failure occurs in the input side mechanism such as an electric motor, the reverse input cutoff clutch 1 is switched to the first state. In the first state, the pressing surface 43 is allowed to be pressed against the pressed surface 7, so the reverse input cutoff function of the reverse input cutoff clutch 1 is enabled.

[0101] On the other hand, if a fault occurs in the input-side mechanism such as the electric motor, the reverse input cutoff clutch 1 is switched to the second state. In the second state, the pressing surface 43 is prevented from being pressed against the pressed surface 7, so the reverse input cutoff function of the reverse input cutoff clutch 1 is disabled, and the input member 4, output member 4, engaging element 5, and switching member 6 rotate together regardless of the rotation direction of the output member 4, allowing torque to be transmitted from the output member 4 to the input member 3. In other words, the rotation of the output member 4 is not locked or semi-locked, and the position, attitude, etc. of the driven member connected to the output member 4 can be easily changed.

[0102] The switching member 6 can be supported by any one of the support members among the pressed member 2, the input member 3, the output member 4, and the fixed portion so as to be movable in the axial direction. Specifically, the switching member 6 can be supported by the support member by being fitted into a guide portion that extends in the axial direction and is provided on a part of any one of the support members among the pressed member 2, the input member 3, the output member 4, and the fixed portion so as to be movable in the axial direction.

[0103] In this example, the switching member 6 is supported by the output member 4 so as to be movable in the axial direction. Specifically, the switching member 6 has a base 52 to which a retaining portion 51 is fixed, and the base 52 is fitted into a guide portion provided on the output member 4, extending in the axial direction, so as to be movable in the axial direction. More specifically, in this example, the base 52 is configured in the shape of a hollow circular flat plate, and the guide portion of the output member 4 is configured by the medium diameter portion 34. The switching member 6 is supported by the output member 4 by having the base 52 fitted onto the medium diameter portion 34 so as to be movable in the axial direction without any radial rattle. In this example, the axial position of the switching member 6 when the side surface on the other axial side of the base 52 abuts against the stepped surface 37 of the output shaft portion 33 is defined as the first axial position.

[0104] In this example, the switching member 6 is engaged with the output member 4 in the circumferential direction so as to prevent relative rotation therebetween. Examples of the engagement that can be used include key engagement and spline engagement. In this example, key engagement is used as the engagement. Specifically, in this example, a key 53 that protrudes radially inward and is provided at one circumferential location on the inner peripheral surface of the base 52 is key-engaged with a key groove 54 that extends in the axial direction and is provided at one circumferential location on the outer peripheral surface of the medium diameter portion 34, allowing axial movement, thereby preventing relative rotation between the switching member 6 and the output member 4.

[0105] The pressing portion 51 of the switching member 6 has a portion that presses the pressed portion 46 from the radially outer side only in the second state out of the first state and the second state.

[0106] In other words, the held portion 46 of the engaging element 5 has a portion that is held from the radially outer side by the holding portion 51 only in the second state out of the first state and the second state. The arrangement and shape of the held portion 46 are not limited as long as it is configured to have such a portion.

[0107] The restrained portion 46 can be disposed in the middle or end portion in the width direction of the engaging element 5. Furthermore, the restrained portion 46 can be disposed in the middle or outer end portion in the radial direction of the engaging element 5, and specifically, for example, can be disposed in a portion located radially inward from the input-side engaged portion 44 and radially outward from the output-side engaged portion 45, or in a portion located radially outward from the output-side engaged portion 45. In this example, the restrained portion 46 is provided at the radially outer end portion of the width direction center of the engaging element 5, specifically, at a portion adjacent to the radially outer side of the input-side engaged portion 44, and the radially outer surface of the restrained portion 46 is formed by the radially outer surface of the width direction center of the engaging element 5.

[0108] The shape of the portion of the held portion 46 that is held from the radially outer side by the holding portion 51 may be a plane shape having a generatrix that is linear or curved, such as an arc, or may be an angular shape. In this example, the held portion 46 has, on its radially outer surface, a flat surface portion 50 that is perpendicular to the radial direction of the engaging element 5. In this example, of the held portion 46, the connection portion between the flat surface portion 50 and the side surface on the other axial side, i.e., a corner P that exists on the edge portion on the other axial side of the flat surface portion 50, is the portion that is held from the radially outer side by the holding portion 51.

[0109] The holding portion 51 is configured so that its radially inner surface 55 comes into contact with the held portion 46 as the switching member 6 moves in the axial direction. In this example, the holding portion 51 is provided so as to protrude toward one axial side from a portion of the side surface on one axial side of the base portion 52 that is radially outwardly spaced from the central axis of rotation O, specifically from the radially outer end portion.

[0110] The shape of the holding portion 51 is not limited as long as it is configured to have a portion that holds the held portion 46 from the radially outer side only in the second state out of the first state and the second state.

[0111] For example, when viewed from the axial direction, the retaining portion 51 can have an end face shape that is similar to an arch shape centered on the rotation axis O, a rectangle extending in a direction perpendicular to the line connecting the rotation axis O and the center of the retaining portion 51, a quadrangle such as a trapezoid, a triangle, or any shape similar to these. In this example, when viewed from the axial direction, the retaining portion 51 has an end face shape that is similar to an arch shape centered on the rotation axis O.

[0112] At least one of the pressing portion 51 and the pressed portion 46 can have a guide surface inclined with respect to the axial direction, which moves the engaging element 5 radially inward based on sliding movement between the pressing portion 51 and a part of the other of the pressed portion 46 when the switching member 6 moves from the first axial position to the second axial position. The inclination of the guide surface with respect to the axial direction may be a linear inclination or a curved inclination such as a circular arc.

[0113] In this example, the pressing portion 51 has, as the guide surface, an outer diameter side guide surface 56 provided on a radially inner surface 55. The outer diameter side guide surface 56 is linearly inclined in a direction toward the radially inward direction from the second axial position side toward the first axial position side of the switching member 6, specifically from one axial side to the other axial side. When the switching member 6 moves from the first axial position to the second axial position, the outer diameter side guide surface 56 slides against a corner P that is a part of the pressed portion 46, and as a result, the engaging element 5 is pushed radially inward and moves radially inward.

[0114] In this example, one axial end of the radially inner surface 55 of the pressing portion 51 is formed by a flat surface 57 that is perpendicular to a line connecting the rotation center axis O and the center of the pressing portion 51 in the width direction of the engaging element 5 when viewed from the axial direction. The entire portion of the radially inner surface 55 of the pressing portion 51 that is located on the other axial side of the flat surface 57 is formed by an outer diameter side guide surface 56. The radially outer surface 58 of the pressing portion 51 is formed by a partially cylindrical convex surface centered on the rotation center axis O. The diameter of a circumscribing circle of the radially outer surface 58 centered on the rotation center axis O is smaller than the inner diameter of the pressed surface 7.

[0115] In this example, the holding portion 51 is inserted between the pressed surface 7 and the flat surface portion 50 of the held portion 46 in the axial direction.

[0116] As shown in Figures 1, 2, and 9(a), in a first state in which the switching member 6 is in a first axial position, only the flat surface 57 of the radial inner surface 55 of the retaining portion 51 is positioned between the pressed surface 7 and the flat surface portion 50.

[0117] The distance from the rotation center axis O to the flat surface 57 is greater than the distance from the rotation center axis O to the flat surface portion 50 in a state in which the pressing surface 43 is pressed against the pressed surface 7. Therefore, in the first state, the pressed portion 46 is not pressed from the radially outer side by the pressing portion 51, and the pressing surface 43 is allowed to be pressed against the pressed surface 7.

[0118] As shown in Figure 9(b), in the second state in which the switching member 6 is in the second axial position, not only the flat surface 57 of the radial inner surface 55 of the retaining portion 51 but also one axial side portion of the outer diameter side guide surface 56 are positioned between the pressed surface 7 and the flat surface portion 50.

[0119] In the second state, the distance from the rotation center axis O to the portion of the outer diameter side guide surface 56 that radially overlaps with the corner P of the pressed portion 46 is shorter than the distance from the rotation center axis O to the corner P in a state in which the pressing surface 43 is pressed against the pressed surface 7. For this reason, in the second state, the outer diameter side guide surface 56 presses the corner P from the radial outside, that is, the pressing portion 51 presses the pressed portion 46 from the radial outside, thereby preventing the pressing surface 43 from being pressed against the pressed surface 7.

[0120] The number of holding portions 51 is determined according to the number of engaging elements 5, and when the engaging elements 5 are made up of a plurality of engaging elements 5, the holding portion 51 is also made up of a plurality of holding portions 51. In this example, the engaging elements 5 are made up of two engaging elements 5. Therefore, the holding portion 51 is made up of two holding portions 51 to match the number of engaging elements 5. The two holding portions 51 are arranged at two radially opposite positions on a side surface on one axial side of the base 52, and are spaced apart from each other in the radial direction centered on the central axis of rotation O.

[0121] Any configuration can be employed for the configuration for holding the axial position of the switching member 6 and the configuration for moving the switching member 6 in the axial direction.

[0122] For example, the axial position of the switching member 6 can be maintained by disengaging a switching member-side engaging portion such as a snap fit piece provided on the switching member 6 with the support member, or by hooking a locking member such as a clip between the switching member 6 and the support member. In this case, the operations of engaging and disengaging the switching member-side engaging portion or the locking member, and moving the switching member 6 in the axial direction can be performed by using a tool inserted into the pressed member 2 through a window provided in the pressed member 2.

[0123] Alternatively, a switching member elastic member 64 may be provided that applies elastic force to the switching member 6 in a direction from the second axial position toward the first axial position, and the switching member 6 may be held at the first axial position by the elastic force of the switching member elastic member 64. In this case, a moving mechanism may be further provided that moves the switching member 6 in the axial direction against the elastic force of the switching member elastic member 64. Alternatively, the switching member 6 may be moved in the axial direction by a tool or the like inserted into the pressed member 2 through a window or the like provided in the pressed member 2.

[0124] The reverse input cutoff clutch 1 of this example further includes a switching member elastic member 64 that applies elastic force to the switching member 6 in a direction from the second axial position side toward the first axial position side. In a normal use state of the reverse input cutoff clutch 1 of this example, the switching member 6 is held in the first axial position based on the elastic force of the switching member elastic member 64.

[0125] The elastic member 64 for the switching member can be made of a spring such as a leaf spring, a coil spring, a disc spring, a wave washer, or an elastic material such as rubber, elastomer, synthetic resin, etc. In this example, the elastic member 64 for the switching member is made of one or more wave washers.

[0126] In this example, the switching member elastic member 64 is sandwiched between a reinforcing member 59 that is suspended between the tip ends of the two input-side engaging portions 21 of the input member 3 and the base 52 of the switching member 6. This applies an elastic force to the switching member 6 in a direction from the second axial position toward the first axial position, and presses the other axial side surface of the base 52 against the step surface 37 of the output shaft 33, thereby holding the switching member 6 at the first axial position.

[0127] The reverse input cutoff clutch 1 of this example includes a movement mechanism 65 that moves the switching member 6 from the first axial position to the second axial position against the elastic force of the elastic member 64 for the switching member.

[0128] The structure of the moving mechanism 65 is not particularly limited, and any structure can be adopted as long as it can move the switching member 6 from the first axial position to the second axial position against the elastic force of the switching member elastic member 64.

[0129] For example, the moving mechanism 65 can be configured to include a pressing member that presses the switching member 6 in the axial direction, thereby moving the switching member 6 from a first axial position to a second axial position.

[0130] In this case, for example, the pressing member can be configured as a cam rod that is rotatably supported relative to the pressed member 2 and has a cam surface that presses the switching member 6 in the axial direction as the rotation ensues. Alternatively, the pressing member can be configured as a pressing rod that is supported axially movably relative to the pressed member 2 and presses the switching member 6 in the axial direction as the axial movement ensues.

[0131] Furthermore, the movement mechanism 65 can be pre-assembled into the reverse input cutoff clutch 1 when the reverse input cutoff clutch 1 is assembled into the torque transmission path of the mechanical device, or can be assembled into the reverse input cutoff clutch 1 when a failure occurs in the input side mechanism such as the drive source. When the movement mechanism 65 is to be assembled into the reverse input cutoff clutch 1 when a failure occurs in the input side mechanism such as the drive source, it is preferable to seal the holes 69a, 69b for assembling the movement mechanism 65 with an appropriate type of sealing member such as a press-fit type or a screw-fit type.

[0132] In this example, the movement mechanism 65 is configured to include a pressing member that presses the switching member 6 in the axial direction to move the switching member 6 from a first axial position to a second axial position, and the pressing member is configured by a cam rod 66 that is rotatably supported with respect to the pressed member 2 and has a cam surface 67 that presses the switching member 6 in the axial direction as the pressing member rotates. Also, in this example, the movement mechanism 65 is pre-installed in the reverse input cutoff clutch 1 when the reverse input cutoff clutch 1 is installed in the middle of the torque transmission path of the mechanical device.

[0133] In this example, the cam rod 66 is rotatably supported in a support hole 68 provided in the pressed member 2 .

[0134] In this example, the support hole 68 is configured as a through-hole formed in the large-diameter cylindrical portion 15 of the output element 9 so that its central axis X is skewed relative to the central axis O of the output element 9. In other words, the central axis X of the support hole 68 is not parallel to or intersects with the central axis O of the output element 9. Specifically, in this example, the central axis X of the support hole 68 is disposed at a distance from the central axis O of the output element 9 in the radial direction of the output element 9, and the direction of the central axis X of the support hole 68 is perpendicular to the direction of the central axis O of the output element 9.

[0135] 1 to 4, the support hole 68 is composed of a pair of hole portions 69a, 69b that are coaxially arranged and spaced apart in the direction of the central axis X. Each of the hole portions 69a, 69b opens to the outer peripheral surface and the inner peripheral surface of the large-diameter cylindrical portion 15, and has a circular cross-sectional shape. In this example, the inner diameters of the hole portions 69a, 69b are the same.

[0136] The number of support holes 68 is determined according to the number of cam rods 66, and when the cam rods 66 are made up of a plurality of cam rods 66, the support holes 68 are also made up of a plurality of support holes 68.

[0137] In the reverse input cutoff clutch 1 of this example, the cam rod 66 is configured by two cam rods 66. Therefore, the support holes 68 are configured by two support holes 68 to match the number of cam rods 66. The two support holes 68 are arranged in two locations in the large diameter cylindrical portion 15, sandwiching the central axis of the output side element 9 therebetween.

[0138] 3, the cam rod 66 has a camshaft portion 70 in the axial middle portion and cylindrical pillar portions 71a, 71b on both axial ends. The cam surface 67 is formed by the outer peripheral surface of the camshaft portion 70.

[0139] The distance from the central axis Y of the cam rod 66 to the cam surface 67 is not constant in the circumferential direction around the central axis Y. The cross-sectional shape of the cam surface 67 when cut by an imaginary plane perpendicular to the central axis Y of the cam rod 66 is arbitrary as long as the cam surface 67 has a cam function, and can be, for example, an ellipse, an oval, a rectangle, or a shape similar to these. In this example, the cam surface 67 has an elliptical cross-sectional shape when cut by an imaginary plane perpendicular to the central axis Y of the cam rod 66.

[0140] In this example, the axially intermediate portions of pillar portions 71a, 71b of cam rod 66 are rotatably supported by slide bearings (sleeves) 72a, 72b inserted into hole portions 69a, 69b that form support hole 68, thereby rotatably supporting cam rod 66 on pressed member 2. In this state, cam shaft portion 70 is disposed radially inside large-diameter cylindrical portion 15, and cam surface 67 contacts or faces a side surface on the other axial side of base portion 52 of switching member 6. In this example, cam surfaces 67 of the two cam rods 66 contact or face two radially opposite locations on the side surface on the other axial side of base portion 52.

[0141] In this example, the major axis of cam surface 67 is smaller than the inner diameter of each of hole portions 69a, 69b that constitute support hole 68. Therefore, when assembling reverse input cutoff clutch 1 of this example, camshaft portion 70 can be passed axially through either of two hole portions 69a, 69b.

[0142] In this example, the outer diameters of the pillar portions 71a, 71b are the same size and are smaller than the major axis of the cam surface 67. Therefore, when assembling the reverse input cutoff clutch 1 of this example, the pillar portions 71a, 71b can be passed axially through either of the two hole portions 69a, 69b. In this example, the outer diameters of the pillar portions 71a, 71b are the same size as the minor axis of the cam surface 67. However, the outer diameters of the pillar portions 71a, 71b can also be made different from the minor axis of the cam surface 67.

[0143] When assembling the reverse input cutoff clutch 1 of this example, the cam rod 66 is inserted from the radially outer opening of one of the two holes 69a, 69b (for example, hole 69a). In this case, it is not necessary to pass the camshaft 70 through the other of the two holes 69a, 69b (for example, hole 69b). For this reason, when implementing the present disclosure, the inner diameter of the other hole can be made smaller than the major axis of the cam surface 67, and the pillar portion (for example, pillar portion 71b) of the cam rod 66 can be rotatably supported in the other hole directly, i.e., without using a sliding bearing (sleeve).

[0144] Furthermore, when implementing the present disclosure, the outer diameter of the pillar portion (e.g., pillar portion 71a) of the cam rod 66 arranged inside one of the hole portions (e.g., hole portion 69a) can be set to be equal to or larger than the major axis of the cam surface 67, and the pillar portion can be rotatably supported in the one of the hole portions directly, i.e., without using a sliding bearing (sleeve).

[0145] In this example, the cam rod 66 has an engaged portion 73 at the tip end (the upper end portion in Figures 1 to 5) of one of the pillar portions 71a, and the cam rod 66 can be rotated by a tool engaged with the engaged portion 73. In this example, the engaged portion 73 is formed by an engagement groove that traverses the tip end of one of the pillar portions 71a in the radial direction.

[0146] When the reverse input blocking function of the reverse input blocking clutch 1 is active, that is, in the first state shown in Figures 1, 2, and 9(a), the minor axis direction of the cam surface 67 coincides with the axial direction of the output member 4, and the cam surface 67 is in light contact with or faces the side surface on the other axial side of the base 52 of the switching member 6 via a small gap.

[0147] To switch the reverse input cutoff function of the reverse input cutoff clutch 1 from enabled to disabled, the cam rod 66 is rotated from the first state shown in FIGS. 1, 2, and 9(a) to a rotational position shown in FIG. 9(b) where the longitudinal axis of the cam surface 67 coincides with the axial direction of the output member 4. This causes the cam surface 67 to press the side surface on the other axial side of the base 52 toward one axial side. As a result, the switching member 6 is moved from the first axial position to the second axial position against the elastic force of the switching member elastic member 64. This causes the outer diameter guide surface 56 to slide against the corner P, thereby moving the engaging element 5 radially inward. This switches the clutch 1 to the second state. In this state, the side surface on the other axial side of the base 52 is supported by the cam surface 67, so that the switching member 6 is held in the second axial position.

[0148] When switching the reverse input cutoff function of the reverse input cutoff clutch 1 back to enabled, the cam rod 66 is rotated from the second state shown in Figure 9(b) to a rotational position where the minor axis direction of the cam surface 67 coincides with the axial direction of the output member 4, as shown in Figures 1, 2, and 9(a). This causes the elastic force of the switching member elastic member 64 to move the switching member 6 from the second axial position to the first axial position, thereby switching to the first state.

[0149] As long as the cam rod 66 functions as described above, any material may be used for the cam rod 66. Materials that can be used to form the cam rod 66 include metal materials such as iron alloys and aluminum alloys, as well as synthetic resins containing reinforcing fibers as needed.

[0150] In this example, with two cam rods 66 installed in the reverse input cutoff clutch 1, the rotational phases of the cam surfaces 67 of the two cam rods 66 are matched with each other, and when the switching member 6 is moved in the axial direction, the two cam rods 66 are rotated in synchronization with each other.

[0151] When implementing the reverse-current blocking clutch of the present disclosure, if the cam rod is configured from a plurality of cam rods as in this example, a synchronous rotation mechanism can be attached to the plurality of cam rods, which is made up of a combination of mechanical elements such as gears, friction rollers, sprockets and chains, pulleys and belts, in order to match the rotational phases of the cam surfaces of the plurality of cam rods with each other and rotate the plurality of cam rods in synchronization with each other.

[0152] The reverse input disconnecting clutch 1 of this example can further include a biasing member 74 as an optional component.

[0153] The biasing member 74 elastically biases the engaging element 5 in a direction approaching the pressed surface 7. The biasing member 74 can be made of a spring such as a leaf spring, a coil spring, or a disc spring, or an elastic material such as rubber, elastomer, or synthetic resin. The number of biasing members 74 is not particularly limited and is determined appropriately depending on the number and arrangement of the engaging elements 5.

[0154] In this example, the urging member 74 is configured by two urging members 74 arranged at two positions in the width direction between the radially inner surfaces of the two engaging members 5, and each urging member 74 is configured by a compression coil spring. A protrusion 49 is inserted into the inside of each urging member 74 at both ends in the extension direction. This prevents each urging member 74 from falling off from between the two engaging members 5.

[0155] The two biasing members 74 elastically bias the two engagement elements 5 in a direction that brings them closer to the pressed surface 7 by the force of elastic restoration. As a result, in a neutral state where no torque is applied to either the input member 3 or the output member 4, the pressing surfaces 43 of the two engagement elements 5 are in contact with the pressed surface 7.

[0156] Therefore, in the first state, when a rotational torque is input in reverse to the output member 4, the surface pressure at the contact point between the pressing surface 43 of the engaging element 5 and the pressed surface 7 is quickly increased, and the reverse input cut-off clutch 1 is switched to a locked or semi-locked state, i.e., good locking performance is ensured.

[0157] The reverse input cutoff clutch 1 of this example can include, as an optional component, a reinforcing member 59. The reinforcing member 59 is stretched across the tip ends, which are the other axial end portions of the two input-side engaging portions 21 of the input member 3.

[0158] 4, the reinforcing member 59 has a substantially oval end face shape when viewed in the axial direction. The reinforcing member 59 has a large-diameter through-hole 60 in the center for inserting the output-side engaging portion 30 of the output member 4 therethrough, and also has small-diameter through-holes 61 at two locations on either side of the large-diameter through-hole 60 in the longitudinal direction.

[0159] The reinforcing member 59 is supported and fixed to the two input side engaging portions 21 by threading support bolts 62 inserted through the respective small diameter through holes 61 into threaded holes 63 opening in the other axial end faces of the respective input side engaging portions 21. In this way, in this example, the reinforcing member 59 is provided so as to bridge between the tip ends of the two input side engaging portions 21 provided on the input member 3. Therefore, even if a force directed radially outward is applied from the engager 5 to the input side engaging portions 21 when the reverse input cutoff clutch 1 is switched from the locked state or semi-locked state to the unlocked state, the two input side engaging portions 21 can be effectively prevented from deforming so as to move away from each other.

[0160] As described above, according to the reverse input cutoff clutch 1 of this example, even after the reverse input cutoff clutch 1 is incorporated in the middle of the torque transmission path of a mechanical device, the reverse input cutoff function can be disabled by switching the reverse input cutoff clutch 1 of this example from the first state to the second state by moving the switching member 6 from the first axial position to the second axial position. Therefore, when a failure occurs in the input side mechanism such as the drive source, the position and posture of the driven member can be changed by applying an external force to the driven member, thereby ensuring safety.

[0161] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIGS. 10 to 11(b).

[0162] In the reverse input cutoff clutch 1a of this example, instead of engaging the switching member 6a in the circumferential direction with the output member 4a so as to prevent relative rotation therebetween as in the first example, the retaining portion 51 of the switching member 6a is engaged in the circumferential direction with the engaging element 5 so as to prevent relative rotation between the switching member 6a and the engaging element 5. As a result, when the engaging element 5 rotates relative to the pressed member 2a, the engaging element 5 and the switching member 6a rotate integrally.

[0163] Specifically, in this example, the inner circumferential surface of the base portion 52a of the switching member 6a and the outer circumferential surface of the medium diameter portion 34a of the output member 4a are each formed of a cylindrical surface over the entire circumference, and the inner circumferential surface of the base portion 52a is externally fitted onto the outer circumferential surface of the medium diameter portion 34a with a clearance fit. Furthermore, based on the engagement between the radially inner surface 55 of the pressing portion 51 of the switching member 6a and the pressed portion 46 of the engaging element 5, relative rotation between the switching member 6a and the engaging element 5 is prevented.

[0164] In the first state of the reverse input cut-off clutch 1a, a small gap exists between the radial inner surface 55 of the holding portion 51 and the flat surface 57 of the held portion 46, and therefore relative rotation between the switching member 6a and the engaging element 5 is permitted by the amount of this small gap, but further relative rotation between the switching member 6a and the engaging element 5 is prevented based on the engagement between the radial inner surface 55 of the holding portion 51 and the flat surface 57 and / or corner portion P of the held portion 46.

[0165] In this example, the configuration of the pressing member included in the movement mechanism 65a is different from that of Example 1. In this example, the pressing member is configured by a pressing rod 75 that is supported so as to be movable in the axial direction relative to the pressed member 2a, and that presses the switching member 6a in the axial direction as it moves in the axial direction.

[0166] In this example, the pressing rod 75 is supported by a support hole 76 provided in the pressed member 2a so as to be movable in the axial direction.

[0167] The mode of axial movement of the pressing rod 75 relative to the support hole 76 can be, for example, a mode in which the pressing rod 75 is threaded into the support hole 76 formed by a screw hole and the pressing rod 75 is moved in the axial direction by rotating the pressing rod 75, or a mode in which the pressing rod 75 is inserted into the support hole 76 formed by a through hole and moved in the axial direction. In this example, a mode is adopted in which the pressing rod 75 is threaded into the support hole 76 formed by a screw hole and the pressing rod 75 is moved in the axial direction by rotating the pressing rod 75.

[0168] Specifically, in this example, the support hole 76 is configured as a threaded hole that passes through a portion of the connecting portion 17a of the output element 9a in the axial direction in the circumferential direction.

[0169] The number of support holes 76 is determined according to the number of pressing rods 75, and when the pressing rods 75 are made up of a plurality of pressing rods 75, the support holes 76 are also made up of a plurality of support holes 76.

[0170] In this example, the pressing rod 75 is configured by two pressing rods 75. Therefore, the support holes 76 are configured by two support holes 76 to match the number of pressing rods 75. The two support holes 76 are arranged at two locations on opposite radial sides of the connecting portion 17a.

[0171] The pressure rod 75 can be configured by a plunger, a bolt, etc. that is screwed into the support hole 76 .

[0172] In this example, the pressing rod 75 is constituted by a plunger. Specifically, the pressing rod 75 includes a shaft 77 having a male thread portion on its outer circumferential surface and a retaining hole 83 in its radial center that opens only to one end surface in the axial direction, a contactor 78 that is fitted into the retaining hole 83 and has a tip portion, which is the end portion on one axial side, protruding from the retaining hole 83, and a compression coil spring 84 that is arranged between the bottom surface of the retaining hole 83 and the contactor 78 and applies a resilient force to the contactor 78 toward one axial side.

[0173] The retaining hole 83 has a small-diameter portion 85 at one axial end, which has a smaller inner diameter than the portion adjacent to it on the other axial side. Furthermore, the contactor 78 has a large-diameter portion 86, located on the other axial side of the small-diameter portion 85, within the portion of the contactor 78 disposed inside the retaining hole 83. The small-diameter portion 85 and the large-diameter portion 86 prevent the entire contactor 78 from slipping out of the retaining hole 83. Furthermore, when a force directed toward the other axial side against the elastic force of the compression coil spring 84 is applied to the contactor 78, the contactor 78 can move axially to retreat into the retaining hole 83.

[0174] The contactor 78 is formed of a ball or a pin. When the contactor 78 is formed of a ball, the large diameter portion 86 is formed of the central portion of the ball in the axial direction of the pressing rod 75. When the contactor 78 is formed of a pin, the large diameter portion 86 is formed of the outward flange portion of the pin provided at the other end of the pin in the axial direction of the pressing rod 75. In this example, the contactor 78 is formed of a pin.

[0175] The shaft 77 has an engaged portion 79 at the other axial end, and the pressing rod 75 can be rotated by a tool engaged with the engaged portion 79. In this example, the engaged portion 79 is configured as an engagement hole that can be engaged with a tool such as a hex wrench.

[0176] The pressing rod 75 is supported in the support hole 76 by threading the male thread portion of the shaft 77 into the support hole 76, and is capable of axial movement relative to the support hole 76 based on the rotation of the pressing rod 75. With the pressing rod 75 supported in the support hole 76 in this manner, the tip end of the contactor 78 is in contact with or faces the side surface on the other axial side of the base 52a of the switching member 6a. In this example, the tip ends of the contactors 78 of the two pressing rods 75 are in contact with or face two radially opposite points on the side surface on the other axial side of the base 52a.

[0177] In this example, in the first state shown in Figures 10 and 11(a), the tip of the contactor 78 is in light contact with or faces the side surface on the other axial side of the base part 52a of the switching member 6a via a small gap.

[0178] In this example, as in the first example, the switching member elastic member 64 applies elastic force to the switching member 6a in a direction from the second axial position toward the first axial position, and the side surface on the other axial direction of the base 52a of the switching member 6a is pressed against the stepped surface 37 of the output shaft 33, thereby holding the switching member 6a at the first axial position. However, when implementing the present disclosure, with the switching member 6a disposed at the first axial position, an axial gap can be provided between the side surface on the other axial direction of the base 52a of the switching member 6a and the stepped surface 37, and the side surface on the other axial direction of the base 52a can be supported by the tip of the contact 78 of the pressing rod 75, thereby holding the switching member 6a at the first axial position.

[0179] In this example, when switching the reverse input cutoff function of the reverse input cutoff clutch 1a from enabled to disabled, as shown in Fig. 11(b), the pressing rods 75 are rotated by a tool engaged with the engaged portions 79 to move them toward one axial direction side from the first state shown in Fig. 10 and Fig. 11(a), and the tip ends of the contactors 78 of the pressing rods 75 press the side surface on the other axial side of the base portion 52 toward one axial direction side. This moves the switching member 6a from the first axial position to the second axial position against the elastic force of the switching member elastic member 64.

[0180] When the reverse input blocking function is switched to be enabled again, each pressing rod 75 is rotated by a tool engaged with the engaged portion 79 from the second state shown in Fig. 11(b) toward the other axial side as shown in Fig. 10 and Fig. 11(a). As a result, the elastic force of the switching member elastic member 64 moves the switching member 6a from the second axial position to the first axial position.

[0181] Other configurations and effects of this example are the same as those of the first example.

[0182] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIG.

[0183] In this example, the engaging piece 5a has a radial recess 80 that recesses radially inward at the middle of the width direction at the radially outer end. In this example, by engaging the retaining portion 51 of the switching member 6 with the radial recess 80, relative rotation between the switching member 6 and the engaging piece 5a is prevented.

[0184] Specifically, in this example, the inner surface of the radial recess 80 is configured with a pair of inner side surfaces 81 facing each other in the width direction of the engaging piece 5a, and a bottom surface 82 facing radially outward. In this example, the flat surface portion 48 is configured with the bottom surface 82.

[0185] In this example, the retaining portion 51 of the switching member 6 is disposed inside the radial recess 80. In this state, both circumferential side surfaces of the retaining portion 51 are closely opposed to or abut against the pair of inner side surfaces 81. In this example, relative rotation between the switching member 6 and the engaging piece 5a is prevented based on the engagement between the radial inner side surface 55 of the retaining portion 51 and the flat surface 57 and / or the corner portion P (see FIG. 10 ) and / or the engagement between the both circumferential side surfaces of the retaining portion 51 and the pair of inner side surfaces 81.

[0186] Other configurations and effects of this example are the same as those of the second example.

[0187] [Example 4] A fourth example of the embodiment of the present disclosure will be described with reference to FIG.

[0188] In this example, the held portion 46a provided on the engaging element 5b has an inner diameter side guide surface 87 that is in surface contact with an outer diameter side guide surface 56 that corresponds to a part of the holding portion 51, as a guide surface inclined with respect to the axial direction, which moves the engaging element 5b radially inward based on sliding with a part of the holding portion 51. The inner diameter side guide surface 87 is configured as an inclined surface that is inclined in the same direction and at the same angle as the outer diameter side guide surface 56.

[0189] According to the structure of this example, when the switching member 6 is moved in the axial direction, the outer diameter side guide surface 56 of the retaining portion 51 of the switching member 6 slides in surface contact with the inner diameter side guide surface 87 of the retained portion 46a, and therefore the retained portion 46a is stably guided by the outer diameter side guide surface 56, thereby stabilizing the posture of the engaging member 5b when it moves radially.

[0190] Other configurations and effects of this example are the same as those of the first example.

[0191] The first to fourth examples of the embodiment of the present disclosure can be combined as appropriate as long as no contradiction occurs. [Explanation of symbols]

[0192] 1, 1a Reverse input cutoff clutch 2, 2a Pressurized member 3 Input member 4, 4a Output member 5, 5a, 5b engager 6, 6a Switching member 7 Pressed surface 8 Input side element 9, 9a Output side element 10 Small diameter cylinder part 11 Large diameter cylinder 12 Connection 13 Inward flange 14 Outward flange 15 Large diameter cylinder 16 Small diameter cylinder part 17, 17a connection 18 Inward flange 19 Through hole 20 volts 21 Input side engagement portion 22 Input shaft 23 Input flange 24 Radial inner surface 25 Radial outer surface 26 Radial rolling bearing 27 Outer ring 28 Inner Circle 29 Rolling elements 30 Output side engagement portion 31 Flat surface 32 Convex curved surface 33 Output shaft 34, 34a Medium diameter part 35 Large diameter section 36 Small diameter section 37 Step surface 38 Step surface 39 Radial Rolling Bearings 40 outer ring 41 Inner circle 42 rolling elements 43 Pressing surface 44 Input side engaged portion 45 Output side engaged part 46, 46a Retained part 47 Radial inner surface 48 Flat surface section 49 Convex 50 Flat surface section 51 Retaining part 52, 52a base 53 keys 54 Keyway 55 Radial inner surface 56 Outer diameter guide surface 57 Flat surface 58 Radial outer surface 59 Reinforcement members 60 Large diameter through hole 61 Small diameter through hole 62 Support bolt 63 screw hole 64 Elastic member for switching member 65, 65a Moving mechanism 66 Cam rod 67 Cam surface 68 Support hole 69a, 69b hole 70 Camshaft 71a, 71b Pillar section 72a, 72b Plain bearing 73 Engaged part 74 biasing member 75 Push rod 76 Support hole 77 Shaft 78 Contactor 79 Engaged part 80 Radial recess 81 Inner surface 82 bottom 83 Retention hole 84 Compression coil spring 85 Small diameter section 86 Large diameter section 87 Inner diameter guide surface

Claims

1. a pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion disposed radially inside the pressed surface and disposed coaxially with the pressed surface; an output member having an output side engaging portion disposed radially inward of the input side engaging portion and disposed coaxially with the pressed surface; an engaging element having a pressing surface opposing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and arranged to be movable in a radial direction; When a rotational torque is input to the input member, the input side engaging portion engages with the input side engaged portion, and the engaging element moves away from the pressed surface, causing the output side engaged portion to engage with the output side engaging portion, thereby transmitting the rotational torque input to the input member to the output member. Conversely, when a rotational torque is input in reverse to the output member, the output side engaging portion engages with the output side engaged portion, and the pressing surface is pressed against the pressed surface, causing the pressing surface to frictionally engage with the pressed surface. A reverse input cutoff clutch, a switching member having a suppressing portion and arranged to be movable in an axial direction; The engaging element has a restrained portion that can be engaged with the restraining portion, In a first state in which the switching member is in a first axial position, the suppressing portion does not suppress the suppressed portion from the radially outer side, thereby allowing the pressing surface to be pressed against the pressed surface, and in a second state in which the switching member is in a second axial position, the suppressing portion suppresses the suppressed portion from the radially outer side, thereby preventing the pressing surface from being pressed against the pressed surface. Reverse input cut-off clutch.

2. 2. The reverse input cutoff clutch according to claim 1, wherein at least one of the restraining portion and the restrained portion has a guide surface inclined with respect to the axial direction that moves the engaging element radially inward based on sliding between the other of the restraining portion and the restrained portion when the switching member moves from the first axial position to the second axial position.

3. 3. The reverse input cutoff clutch according to claim 2, wherein the guide surface is an outer diameter side guide surface provided on a radially inner surface of the retaining portion.

4. 4. The reverse input cutoff clutch according to claim 3, wherein the guide surface is an inner diameter side guide surface that is provided on the held portion and is capable of surface contact with the outer diameter side guide surface.

5. 2. The reverse input cutoff clutch according to claim 1, further comprising a switching member elastic member that applies elastic force to said switching member in a direction from said second axial position side toward said first axial position side.

6. 6. The reverse input disconnect clutch according to claim 5, further comprising a movement mechanism that moves the switching member from the first axial position to the second axial position against the elastic force of the switching member elastic member.

7. 7. The reverse input disconnect clutch according to claim 6, wherein the movement mechanism includes a pressing member that presses the switching member in the axial direction to move the switching member from the first axial position to the second axial position.

8. 8. The reverse input cutoff clutch according to claim 7, wherein the pressing member is rotatably supported relative to the pressed member and is configured as a cam rod having a cam surface that presses the switching member in the axial direction as the pressing member rotates.

9. 8. The reverse input cutoff clutch according to claim 7, wherein the pressing member is configured by a pressing rod that is supported so as to be movable in the axial direction relative to the pressed member and that presses the switching member in the axial direction as the pressing member moves in the axial direction.

10. 2. The reverse input disconnect clutch according to claim 1, wherein the switching member is supported by the output member so as to be movable in the axial direction.

11. 2. The reverse input disconnect clutch according to claim 1, wherein said switching member is circumferentially engaged with said output member so as to be prevented from rotating relative to said output member.

12. 2. The reverse input disconnect clutch according to claim 1, wherein the retaining portion of the switching member is engaged with the engaging element in the circumferential direction so as to prevent relative rotation between the switching member and the engaging element.

13. 13. The reverse input cutoff clutch according to claim 12, wherein the engaging element has a radial recess that recesses radially inward at a widthwise intermediate portion of an end portion of the radially outer side, and relative rotation between the switching member and the engaging element is prevented by engaging the pressing portion with the radial recess.

Images