Reverse input cutoff clutch

Abstract

To provide a reverse input cutoff clutch that can regulate axial movement of an engagement piece relative to an output member while suppressing an increase in the number of components.SOLUTION: A reverse input cutoff clutch includes a member to be pressed 2, an input member 3, an output member 4, and an engagement piece 5. The output member 4 includes a pair of regulating parts 18a, 18b formed integrally with the output member 4 and disposed in a position of holding the engagement piece 5 from both axial sides to regulate axial movement of the engagement piece 5 relative to the output member 4 with the pair of regulating parts 18a, 18b.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] Reverse input cutoff clutches are broadly classified into locking and free types depending on the mechanism that cuts off the rotational torque that is reversely input to the output member. A locking reverse input cutoff clutch is equipped with a mechanism that prevents the output member from rotating when rotational torque is reversely input to the output member. On the other hand, a free type reverse input cutoff clutch is equipped with a mechanism that causes the output member to spin freely when rotational torque is input to the output member. Whether to use a locking reverse input cutoff clutch or a free type reverse input cutoff clutch is determined appropriately depending on the application of the device into which the reverse input cutoff clutch is incorporated, etc.

[0004] International Publication No. 2023 / 136149 describes a locking reverse input disconnection clutch, which includes a pressed member, an input member, an output member, and an engagement element.

[0005] The pressed member has a pressed surface on its inner circumferential surface.

[0006] The input member has an input-side engaging portion disposed radially inside the pressed surface, and is disposed coaxially with the pressed surface.

[0007] The output member has an output-side engaging portion that is arranged radially inward of the input-side engaging portion on the radially inner side of the pressed surface, and is arranged coaxially with the pressed surface.

[0008] The engaging element has a pressing surface facing 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 is arranged so as to be able to move in a first direction, which is the direction towards or away from the pressed surface.

[0009] In a conventional reverse input cut-off clutch, when a rotational torque is input to the input member, the input-side engaging portion engages with the input-side engaged portion, causing the engaging element to move in a direction away from the pressed surface and engaging 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. On the other hand, when a rotational torque is input in reverse to the output member, the output-side engaging portion engages with the output-side engaged portion, causing the engaging element to move in a direction approaching the pressed surface, pressing the pressing surface against the pressed surface and causing the pressing surface to frictionally engage with the pressed surface. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2023 / 136149 Brochure Summary of the Invention [Problem to be solved by the invention]

[0011] In the reverse input cutoff clutch described in WO 2023 / 136149, if the axial movement of the engaging element relative to the input member and the output member is not restricted, the engaging element may tilt in the axial direction. If the engaging element moves radially outward while remaining tilted in the axial direction, the pressing surface and the pressed surface may locally come into contact and bite together, which may unnecessarily increase the force required to switch from a locked state or a semi-locked state to an unlocked state or a semi-unlocked state, or may cause deformation of the pressing surface and / or the pressed surface.

[0012] In the reverse input cut-off clutch described in International Publication No. 2023 / 136149, a pair of spacers are installed on both axial sides of the engaging element, and a stopper member engaged with the output member prevents the spacer located on the tip side of the output member from coming loose, thereby restricting the axial movement of the engaging element relative to the input and output members.

[0013] However, if restricting members such as a pair of spacers and stopper members are used in addition to the input member, output member, and engaging member to restrict the axial movement of the engaging member relative to the input member and output member, the number of parts increases, resulting in inconveniences such as increased part management costs.

[0014] An object of the present disclosure is to provide a reverse input cutoff clutch that can restrict axial movement of an engagement element relative to an output member while reducing the number of parts. [Means for solving the problem]

[0015] 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 facing 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 first direction which is a direction in which the pressing surface approaches or moves away from the pressed surface; Equipped with.

[0016] When a rotational torque is input to the input member, the engaging element moves in the first direction away from the pressed surface based on the engagement of the input side engaging portion with the input side engaged portion, and transmits the rotational torque input to the input member to the output member by engaging the output side engaged portion with the output side engaging portion, whereas 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.

[0017] The output member has a pair of regulating portions that are integrally formed with the output member and positioned to sandwich the engaging element from both axial sides, and the pair of regulating portions regulate the axial movement of the engaging element relative to the output member.

[0018] In a second aspect of the reverse input disconnection clutch of the present disclosure, in the reverse input disconnection clutch of the first aspect of the present disclosure, The pair of restricting portions are provided so as to protrude from portions of the output member adjacent to both axial sides of the output-side engaging portion toward a side closer to the pressed surface in the first direction.

[0019] A reverse input disconnection clutch according to a third aspect of the present disclosure is the reverse input disconnection clutch according to the second aspect of the present disclosure, a biasing member that elastically biases the engaging element in a direction toward the pressed surface, the biasing member is configured by a leaf spring elastically sandwiched between the output member and the engaging element, and has a pair of support plate portions that engage with both side portions of the engaging element in a second direction that is perpendicular to both the axial direction of the pressed surface and the first direction, and a pair of pressed plate portions that are arranged in portions offset from the engaging element on both sides in the axial direction, and each of which connects the pair of support plate portions together, The pair of pressed plate portions elastically contact the tip surfaces of the pair of restricting portions that face the pressed surface side in the first direction.

[0020] A fourth aspect of the present disclosure is a reverse input disconnection clutch according to either the first or second aspect of the present disclosure, further comprising a biasing member that elastically biases the engagement element in a direction that brings it closer to the pressed surface. In this case, the biasing member can be formed of, for example, a compression coil spring.

[0021] In a reverse input cutoff clutch of a fifth aspect of the present disclosure, in the reverse input cutoff clutch of any one of the first to fourth aspects of the present disclosure, the engagement element is configured by two engagement elements. [Effects of the Invention]

[0022] According to the reverse input disconnection clutch of one aspect of the present disclosure, it is possible to restrict axial movement of the engagement element relative to the output member while reducing the number of parts. [Brief explanation of the drawings]

[0023] [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 exploded perspective view of the reverse input cutoff clutch of the first example. [Figure 3] FIG. 3 is an enlarged view of part A in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line BB in FIG. 1, with some parts omitted. [Figure 5]FIG. 5 is a cross-sectional view taken along CC in FIG. 1, in which the two compression coil springs are omitted. [Figure 6] FIG. 6 is a view similar to FIG. 5, showing a state in which a rotational torque is input to the input member. [Figure 7] FIG. 7 is a view similar to FIG. 5, showing a state in which a rotational torque is reversely input to the output member. [Figure 8] FIG. 8 is a cross-sectional view of a reverse input disconnecting clutch according to a second example of an embodiment of the present disclosure. [Figure 9] FIG. 9 is a cross-sectional view of a reverse input disconnecting clutch according to a third example of an embodiment of the present disclosure. [Figure 10] FIG. 10 is an exploded perspective view of a portion of the reverse input cutoff clutch of the third example. [Figure 11] FIG. 11 is a diagram corresponding to FIG. 4 and showing a reverse input cutoff clutch according to a third example. DETAILED DESCRIPTION OF THE INVENTION

[0024] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS.

[0025] In the following description, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the reverse input disconnection clutch 1, more specifically the axial direction, radial direction, and circumferential direction of the pressed surface 6 of the pressed member 2 that constitutes the reverse input disconnection clutch 1. In this example, 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 input member 3, and also coincide with the axial direction, radial direction, and circumferential direction of the output member 4. One axial side is the input member 3 side (right side in FIG. 1), and the other axial side is the output member 4 side (left side in FIG. 1).

[0026] The direction of the pressing surface 34 of the engaging element 5 toward or away from the pressed surface 6 is defined as a first direction (the up-and-down direction in Figs. 1 and 3 to 7), and the direction perpendicular to both the axial direction of the pressed surface 6 and the first direction is defined as a second direction (the front-to-back direction in Figs. 1 and 3, the left-to-right direction in Figs. 4 to 7). The radial direction of the engaging element 5 (the direction indicated by arrow A in Fig. 5) corresponds to the first direction, and the width direction of the engaging element 5 (the direction indicated by arrow B in Fig. 5) corresponds to the second direction.

[0027] <Explanation of the structure of the reverse input cutoff clutch> The reverse input cutoff clutch 1 of this example includes a pressed member 2, an input member 3, an output member 4, and an engaging element 5. When a rotational torque is input to the input member 3, the engaging element 5 moves in a direction away from the pressed member 2 based on the engagement between the input member 3 and the engaging element 5, engaging the output member 4 and transmitting the rotational torque input to the input member 3 to the output member 4, whereas when a rotational torque is input in reverse to the output member 4, the engaging element 5 presses the pressing surface of the engaging element 5 against the pressed surface of the pressed member 2 based on the engagement between the output member 4 and the engaging element 5, causing frictional engagement. As a result, the reverse input cutoff clutch 1 transmits the rotational torque input to the input member 3 to the output member 4, while completely cutting off the rotational torque input in reverse to the output member 4 so that it is not transmitted to the input member 3, or it transmits only a portion of the torque to the input member 3 and cuts off the remainder, thereby providing a reverse input cutoff function.

[0028] The materials for the pressed member 2, input member 3, output member 4, and engaging element 5 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, input member, output member, and engaging element can be made of the same material or different materials.

[0029] As long as the condition that the output member 4 is locked or semi-locked when a rotational torque is input in reverse to the output member 4 is met, a lubricant can be applied to the contact points between the pressed member 2, input member 3, output member 4, and engaging element 5. Alternatively, at least one of the pressed member 2, input member 3, output member 4, and engaging element 5 can be made of oil-impregnated metal.

[0030] In the reverse input cut-off clutch 1 of this example, the output member 4 has a pair of regulating portions 18a, 18b that are integrally formed with the output member 4 and are positioned to sandwich the engaging element 5 from both axial sides, and the pair of regulating portions 18a, 18b regulate the axial movement of the engaging element 5 relative to the output member 4.

[0031] The pressed member 2 has a pressed surface 6 on its inner circumferential surface.

[0032] 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.

[0033] The pressed surface 6 has a circular ring shape when viewed in the axial direction, and in this example has a cylindrical surface shape whose inner diameter does not change in the axial direction, although this is not limited to this.

[0034] The input-side engaging portion 13 of the input member 3 and the output-side engaging portion 17 of the output member 4 are coaxially arranged on the radially inner side of the pressed surface 6, and the engaging element 5 is arranged so as to be movable towards and away from the pressed surface 6. The input-side engaging portion 13, the output-side engaging portion 17, and the engaging element 5 are rotatable on the radially inner side of the pressed surface 6. The pressed surface 6 forms a surface that comes into contact with the pressing surface 34 of the engaging element 5 when the engaging element 5 moves in a direction approaching the pressed surface 6.

[0035] There are no limitations on the structure of the pressed member 2 as long as it has a pressed surface 6 on its inner circumferential surface. The pressed member 2 can be formed of a single member having the pressed surface 6, or can be formed by combining, for example, an input side element and an output side element, either of which has the pressed surface 6.

[0036] In this example, the pressed member 2 includes an output element 7 having a pressed surface 6, and an input element (not shown).

[0037] The output element 7 has an inner peripheral surface shaped like a stepped cylindrical surface. That is, the inner peripheral surface of the output element 7 is formed by connecting a large-diameter cylindrical surface portion 8 on one axial side with a small-diameter cylindrical surface portion 9 on the other axial side by a connecting surface portion 10 facing one axial side. In this example, the large-diameter cylindrical surface portion 8 forms the pressed surface 6. The output element 7 has an inward flange portion 11 that protrudes radially inward at the end on the other axial side of the small-diameter cylindrical surface portion 9.

[0038] In this example, the input element is fitted (spigot-fitted) to the output element 7 without any rattle, and the output element 7 and the input element are positioned radially, and then the output element 7 and the input element are joined together with a joining member such as a bolt to form the pressed member 2. The pressed member 2 is supported and fixed to the fixed portion by threading a bolt inserted into a through-hole provided in the fixed portion into a screw hole 12 opening on the side surface of the output element 7 on the other axial side.

[0039] The input member 3 has an input-side engaging portion 13 arranged radially inside the pressed surface 6 , and is arranged coaxially with the pressed surface 6 .

[0040] The input member 3 is connected to an input side mechanism such as an electric motor, and receives a rotational torque, and is configured to be rotatable on the radially inner side of the pressed surface 6 by the input of the rotational torque.

[0041] The input-side engaging portion 13 is provided at a portion radially outwardly deviated from the central axis O of rotation of the input member 3, and is arranged at a position where it can engage with the input-side engaged portion 35 of the engaging element 5. The input-side engaging portion 13 is configured so that its radially inner surface 15 engages with, or more specifically comes into contact with, the radially inner surface 37 of the input-side engaged portion 35 as the input member 3 or the engaging element 5 rotates.

[0042] The input-side engaging portion 13 can be attached directly to the output shaft of the input-side mechanism, or can be attached to an input shaft portion that is provided on the input member 3 and connected to the input-side mechanism. In this example, the input member 3 has an input shaft portion 14 in addition to the input-side engaging portion 13.

[0043] The input shaft portion 14 has a substantially cylindrical shape.

[0044] The input member 3 can be rotatably supported by the pressed member 2 or the fixed portion. In this example, the input shaft 14 of the input member 3 is rotatably supported inside the input element by a radial bearing. The input shaft 14 is connected to the input mechanism.

[0045] The input side engaging portion 13 protrudes from a portion of the end face on the other axial side of the input shaft portion 14 that is radially outwardly spaced from the rotation center axis O toward the other axial side.

[0046] The shape of the input side engaging portion 13 is not limited as long as it is configured to engage with the input side engaged portion 35 of the engaging element 5. For example, the input side engaging portion 13 may have a shape that is symmetrical in the circumferential direction, or may have a shape that is asymmetrical in the circumferential direction. In this example, the input side engaging portion 13 has a shape that is symmetrical in the circumferential direction.

[0047] In this example, the input-side engaging portion 13 has a generally arch-shaped configuration when viewed in the axial direction. Of the radially inner surface 15 of the input-side engaging portion 13, a circumferentially intermediate portion is configured as a flat surface perpendicular to a line connecting the rotation axis O and the center of the input-side engaging portion 13 when viewed in the axial direction, and both circumferential side portions are configured as partially cylindrical convex surfaces that slope radially outward toward both circumferential sides. The radially outer surface 16 of the input-side engaging portion 13 is configured as a partially cylindrical convex surface centered on the rotation axis O.

[0048] The number of input side engaging portions 13 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 input side engaging portion 13 is also made up of a plurality of input side engaging portions 13.

[0049] In the reverse input cutoff clutch 1 of this example, the engaging elements 5 are configured by two engaging elements 5. Therefore, the input side engaging portion 13 is configured by two input side engaging portions 13 to match the number of engaging elements 5. The two input side engaging portions 13 are arranged at two radially opposite positions on the radially outer side of the end face on the other axial side of the input shaft portion 14, and are spaced apart from each other in the radial direction of the input member 3.

[0050] The output member 4 has an output-side engaging portion 17 that is arranged radially inward of the input-side engaging portion 13, and is arranged coaxially with the pressed surface 6. The output member 4 is also arranged coaxially with the input member 3, radially inward of the pressed surface 6.

[0051] The output member 4 is connected to an output side mechanism such as a reduction mechanism, and is configured to output a rotational torque to the output side mechanism as it rotates.

[0052] The output side engaging portion 17 has a portion that can engage with the output side engaged portion 36 of the engaging element 5, and this engageable portion is located radially inward of the input side engaging portion 13 and radially outward from the rotation center axis O of the output member 4, and is arranged at a position where it can engage with the output side engaged portion 36 of the engaging element 5. The output side engaging portion 17 is configured so that this portion engages with the output side engaged portion 36 as the output member 4 or the engaging element 5 rotates.

[0053] The shape of the output side engaging portion 17 is not limited as long as it has a portion that can engage with the output side engaged portion 36 .

[0054] The number of portions of the output side engaging portion 17 that engage with the output side engaged portions 36 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 17 is also configured to have a plurality of engaging portions. In this example, the output side engaging portion 17 is configured to have portions that engage with two of the output side engaged portions 36, matching the number of engaging elements 5.

[0055] The output-side engaging portion 17 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 17, which is the portion that engages with the output-side engaged portion 36, is not constant in the circumferential direction.

[0056] The cross-sectional shape of the output-side engaging portion 17 when cut along an imaginary plane perpendicular to the central axis O of rotation of the output member 4 can be any shape as long as the output-side engaging portion 17 has a cam function, and can be, for example, a substantially rectangular or oval shape, a parallelogram, a trapezoid, or the like. In this example, the output-side engaging portion 17 has a substantially rectangular or oval cross-sectional shape when cut along an imaginary plane perpendicular to the central axis O of the rotation of the output member 4, as shown in FIG. 5. The outer circumferential surface of the output-side engaging portion 17 is made up of side surfaces 24 on both sides in the short direction of the cross-sectional shape (the short axis direction, the up-and-down direction in FIGS. 1, 3, 4, and 5) and end surfaces 25 on both sides in the long direction of the cross-sectional shape (the long axis direction, the front-to-back direction in FIGS. 1 and 3, the left-to-right direction in FIGS. 4 and 5).

[0057] The longitudinally intermediate portion of the side surface 24 is formed by a flat surface perpendicular to the lateral direction. The longitudinally opposite end portions of the side surface 24 are formed by partially cylindrical convex surfaces that are inclined toward the center in the lateral direction as they extend toward both ends in the longitudinal direction. The end surface 25 is formed by a partially cylindrical convex surface centered on the central axis O of rotation of the output member 4.

[0058] In this example, the output side engaging portion 17 is plane-symmetrical with respect to an imaginary plane that passes through the rotation center axis O of the output member 4 and is parallel to the short side direction. Furthermore, the output side engaging portion 17 is plane-symmetrical with respect to an imaginary plane that passes through the rotation center axis O of the output member 4 and is parallel to the longitudinal direction. In other words, the output side engaging portion 17 has a shape that is two-fold symmetrical with respect to the central axis of the output member 4. The output side engaging portion 17 is disposed radially inward of the two input side engaging portions 13 and between the output side engaged portions 36 of the two engaging elements 5.

[0059] The output member 4 has a pair of regulating portions 18a, 18b that are integrally formed with the output member 4 and are positioned to sandwich the engaging element 5 from both axial sides, and the pair of regulating portions 18a, 18b regulate the axial movement of the engaging element 5 relative to the output member 4.

[0060] The shape of the pair of regulating portions 18a, 18b is not limited as long as they are positioned to sandwich the engaging element 5 from both axial sides and are configured to be able to regulate the axial movement of the engaging element 5 relative to the output member 4.

[0061] In this example, the pair of restricting portions 18a, 18b are provided so as to protrude radially outward from portions of the output member 4 that are adjacent to both axial sides of the output side engaging portion 17, i.e., protrude toward the side closer to the pressed surface 6 in relation to the first direction. Note that with respect to the output member 4, the first and second directions refer to the first and second directions of the engaging element 5 when no torque is reversely input to the output member 4 and the longitudinal direction of the output side engaging portion 17 and the radial inner surface (flat surface portion 38) of the engaging element 5 are arranged in parallel.

[0062] The first direction dimension (radial height) and second direction dimension, as well as the shape of each of the pair of regulating portions 18a, 18b, can be set arbitrarily as long as the pair of regulating portions 18a, 18b can effectively regulate the axial movement of the engaging member 5 relative to the output member 4.

[0063] The first and / or second dimension of each of the restriction portions 18a, 18b constituting the pair of restriction portions 18a, 18b can be the same as or different from each other. In this example, the first and second dimension of each of the restriction portions 18a, 18b constituting the pair of restriction portions 18a, 18b are the same as each other.

[0064] The axial width of each of the regulating portions 18a, 18b that make up the pair of regulating portions 18a, 18b can be set arbitrarily as long as the strength and functionality required of the regulating portions 18a, 18b can be ensured, and the smaller the axial width of the regulating portions 18a, 18b, the more it can contribute to shortening the axial dimension of the reverse input cut-off clutch 1.

[0065] The axial widths of the respective restricting portions 18a, 18b constituting the pair of restricting portions 18a, 18b can be the same for the respective restricting portions 18a, 18b, or can be different for the respective restricting portions 18a, 18b. In this example, the axial widths of the respective restricting portions 18a, 18b constituting the pair of restricting portions 18a, 18b are the same for the respective restricting portions 18a, 18b.

[0066] In this example, as shown in FIGS. 2 and 4, each of the pair of restricting portions 18a, 18b has a substantially rectangular end face shape extending in the second direction when viewed from the axial direction.

[0067] The pair of restricting portions 18a, 18b have tip surfaces 44 that face the pressed surface 6 in the first direction. In this example, the tip surfaces 44 are flat. More specifically, the tip surfaces 44 of the pair of restricting portions 18a, 18b, which are arranged with the side surface 24 sandwiched between them in the axial direction, are arranged in the same imaginary plane.

[0068] In this example, of the pair of restricting portions 18a, 18b, the restricting portion 18a on one axial side has a restricting surface 27a on the other axial side. The restricting surface 27a is formed of a flat surface perpendicular to the axial direction. Of the pair of restricting portions 18a, 18b, the restricting portion 18b on the other axial side has a restricting surface 27b on one axial side. The restricting surface 27b is formed of a flat surface perpendicular to the axial direction.

[0069] In this example, corner rounding portions 42 having a concave arc cross section are provided at the connection portions between the side surface 24 provided on the outer peripheral surface of the output side engaging portion 17 and each of the restricting surfaces 27a, 27b, as shown in Fig. 3. This makes it possible to alleviate stress applied to the connection portions between the side surface 24 and the restricting surfaces 27a, 27b.

[0070] The number of pairs of restricting portions 18a, 18b is determined according to the number of engaging elements 5, and when the engaging element 5 is constituted by a plurality of engaging elements 5, the pair of restricting portions 18a, 18b is also constituted by a plurality of pairs of restricting portions 18a, 18b. In this example, the pair of restricting portions 18a, 18b is constituted by two sets of pairs of restricting portions 18a, 18b, corresponding to the number of engaging elements 5. In this example, each set of pairs of restricting portions 18a, 18b is provided so as to protrude in a direction approaching the pressed surface 6 in the first direction from a portion of the output member 4 adjacent to both axial sides of two side surfaces 24 arranged on both sides in the short direction of the output-side engaging portion 17.

[0071] The portions of the output member 4 adjacent to both axial sides of the output side engagement portion 17, i.e., the side surfaces on both sides in the second direction of the axial portion of the output member 4 where the pair of regulating portions 18a, 18b are located, are composed of partially cylindrical convex surfaces arranged in the same imaginary cylindrical plane as the end face 25 of the output side engagement portion 17.

[0072] The reverse input cutoff clutch 1 of this example uses a pair of restricting portions 18a, 18b provided on the output member 4 to restrict axial movement of the engaging element 5 relative to the output member 4. This prevents the engaging element 5 from falling in the axial direction, making it easy to properly maintain the contact state between the pressing surface 34 and the pressed surface 6. In the reverse input cutoff clutch 1 of this example, the pair of restricting portions 18a, 18b are integrally formed with the output member 4, so the number of parts can be reduced compared to when a separate part such as a spacer is provided to restrict axial movement of the engaging element 5 relative to the output member 4. This prevents the cost of managing parts from increasing.

[0073] In this example, the output-side engaging portion 17 and the respective restricting portions 18a, 18b are provided on an intermediate shaft portion 19 provided in the axial middle portion of the output member 4. In addition to the intermediate shaft portion 19, the output member 4 has an output shaft portion 20 and a small diameter shaft portion 21. In particular, in this example, the output member 4 has the intermediate shaft portion 19, the output shaft portion 20, and the small diameter shaft portion 21 integrally configured.

[0074] The output shaft portion 20 has a stepped cylindrical shape and is provided adjacent to the other axial side of the intermediate shaft portion 19. The output shaft portion 20 has an output flange portion 22 that protrudes radially outward from an end portion on one axial side over the entire circumference. The intermediate shaft portion 19 protrudes toward one axial side from the center of an end face 41 on one axial side of the output shaft portion 20.

[0075] The small diameter shaft portion 21 protrudes axially toward one side from the center of an end surface on one axial side of the intermediate shaft portion 19. The small diameter shaft portion 21 has a cylindrical shape.

[0076] The output member 4 can be rotatably supported on the pressed member 2 or the fixed portion. In this example, the output member 4 is rotatably supported radially inside the output element 7 of the pressed member 2 by a radial rolling bearing 28. The outer ring 29 of the radial rolling bearing 28 is fitted securely into the small-diameter cylindrical surface portion 9 of the output element 7 and is axially sandwiched between a side surface on one axial side of the inward flange portion 11 and a segmented annular retaining ring 32a engaged with one axial end of the small-diameter cylindrical surface portion 9. The inner ring 30 of the radial rolling bearing 28 is fitted securely onto the end of one axial side of the output shaft portion 20 and is axially sandwiched between a side surface on the other axial side of the output flange portion 22 and a segmented annular retaining ring 32b engaged with the outer peripheral surface of an axially intermediate portion of the output shaft portion 20.

[0077] In the illustrated example, the radial rolling bearing 28 is configured as a ball bearing that uses balls as rolling elements 31. However, the radial rolling bearing for supporting the output member 4 can also be configured as a tapered roller bearing that uses tapered rollers as rolling elements or a roller bearing that uses cylindrical rollers.

[0078] The small diameter shaft portion 21 of the output member 4 is supported by a slide bearing (sleeve) 33 on the inside of the input shaft portion 14 of the input member 3 so as to be able to rotate freely relative to the input member 3.

[0079] The engaging element 5 has a pressing surface 34 facing the pressed surface 6, an input side engaged portion 35 engageable with the input side engaging portion 13, and an output side engaged portion 36 engageable with the output side engaging portion 17, and is arranged so as to be able to move in a first direction, which is the direction towards or away from the pressed surface 6.

[0080] When a rotational torque is input to the input member 3, the engaging element 5 moves in a direction away from the pressed surface 6 in the first direction based on the engagement of the input side engaging portion 13 with the input side engaged portion 35, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output side engaged portion 36 with the output side engaging portion 17, whereas when a rotational torque is input in the reverse direction to the output member 4, the output side engaging portion 17 engages with the output side engaged portion 36, pressing the pressing surface 34 against the pressed surface 6 and frictionally engaging the pressing surface 34 with the pressed surface 6.

[0081] In this example, the engaging element 5 has a substantially semicircular end face shape when viewed from the axial direction, and has a shape that is symmetrical with respect to the width direction.

[0082] The pressing surface 34 is provided on the radially outer surface of the engaging element 5 facing the pressed surface 6. In this example, the pressing surface 34 is composed of two pressing surfaces 34 provided at two positions spaced apart from each other in the circumferential direction on the radially outer surface of the engaging element 5. Each pressing surface 34 is composed of a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface 6.

[0083] When viewed from the axial direction, the portion of the radially outer surface of the engaging element 5 that is circumferentially offset from the two pressing surfaces 34 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 34. In other words, when the two pressing surfaces 34 are in contact with the pressed surface 6, the portion that is circumferentially offset from the two pressing surfaces 34 does not come into contact with the pressed surface 6.

[0084] The pressing surface 34 preferably has a surface property that gives it a higher coefficient of friction with the pressed surface 6 than the other parts of the engaging element 5. The pressing surface 34 can be formed integrally with the other parts of the engaging element 5, or can be formed by the surface of a friction material fixed to the other parts of the engaging element 5 by adhesion or the like.

[0085] In this example, the input side engaged portion 35 is provided at the radially middle portion of the widthwise center portion of the engaging element 5. The shape of the input side engaged portion 35 is not limited as long as it is configured to be able to engage with the input side engaging portion 13.

[0086] In this example, the input side engaged portion 35 has an approximately oval opening shape extending in the width direction of the engaging element 5 when viewed from the axial direction, and is composed of a through hole that penetrates the radially middle portion of the width direction center of the engaging element 5 in the axial direction.

[0087] The input-side engaged portion 35 has a size that allows the input-side engaging portion 13 to be loosely inserted therein. Therefore, when the input-side engaging portion 13 is inserted inside the input-side engaged portion 35, there is a gap between the input-side engaging portion 13 and the inner surface of the input-side engaged portion 35 in both the width direction and the radial direction of the engaging element 5. Therefore, the input-side engaging portion 13 can be displaced relative to the input-side engaged portion 35 in the rotational direction of the input member 3, and the input-side engaged portion 35 can be displaced in the radial direction of the engaging element 5 relative to the input-side engaged portion 13. In this example, of the inner surface of the input-side engaged portion 35, a radially inner surface 37 facing radially outward is formed by a flat surface perpendicular to the first direction.

[0088] In this example, the output-side engaged portion 36 is provided at the widthwise center of the radially inner surface of the engaging element 5, which is the side surface opposite the pressed surface 6 in the first direction. The shape of the output-side engaged portion 36 is not limited as long as it is configured to be able to engage with the output-side engaging portion 17.

[0089] In this example, the engaging element 5 has, on its radially inner surface, a flat surface portion 38 that is perpendicular to the radial direction of the engaging element 5, and the flat surface portion 38 has two protrusions 39 that protrude radially inward at two positions in the width direction of the engaging element 5. The output-side engaged portion 36 is formed by a portion of the flat surface portion 38 that is located between the two protrusions 39 in the width direction. In this example, the width dimension of the output-side engaged portion 36, i.e., the distance between the two protrusions 39, is greater than the width dimension of the output-side engaging portion 17 in the longitudinal direction.

[0090] In this example, the axial thickness Wa of the engaging member 5 is set to a value slightly smaller than the interval Wb between the pair of restricting portions 18a and 18b in the axial direction, that is, the interval Wb between the pair of restricting surfaces 27a and 27b in the axial direction (Wa < Wb). Conversely, the interval Wb between the pair of restricting portions 18a and 18b in the axial direction is set to a value slightly larger than the axial thickness Wa of the engaging member 5. For this reason, the engaging member 5 is arranged between the pair of restricting portions 18a and 18b, and the movement of the pressed surface 6 in the axial direction is restricted, and the engaging member 5 can move in the first direction with respect to the pressed surface 6.

[0091] In this example, the movement of the engaging member 5 in one axial direction with respect to the output member 4 is restricted by the side surface on one axial side of the engaging member 5 abutting against the restricting surface 27a of the restricting portion 18a on one axial side. Further, the movement of the engaging member 5 in the other axial direction with respect to the output member 4 is restricted by the side surface on the other axial side of the engaging member 5 abutting against the restricting surface 27b of the restricting portion 18b on the other axial side.

[0092] Furthermore, in this example, the axial thickness Wa of the engaging member 5 is set to a value slightly smaller than the interval Wc between the ends on the closer sides of the two corner R portions 42 located on both axial sides of the side surface 24 of the output-side engaging portion 17, that is, the axial width Wc of the side surface 24 (Wa < Wc). Conversely, the interval Wc between the ends on the closer sides of the two corner R portions 42 is set to a value slightly larger than the axial thickness Wa of the engaging member 5. Thereby, by preventing the output-side engaged portion 36 from simultaneously contacting the two corner R portions 42, it is prevented that the output-side engaged portion 36 cannot contact the side surface 24.

[0093] Alternatively or additionally, chamfered portions, such as C-chamfered portions or R-chamfered portions, may be formed on the connecting portions of the engaging element 5 between the side surfaces on both axial sides and the output-side engaged portion 36, respectively, to prevent the output-side engaged portion 36 from simultaneously contacting the two rounded corner portions 42. Forming such chamfered portions on the engaging element 5 prevents the output-side engaged portion 36 from simultaneously contacting the two rounded corner portions 42. By forming such chamfered portions on the engaging element 5, the axial thickness Wa of the engaging element 5 can be made greater than the axial width Wc of the side surface 24 (Wa > Wc), thereby making the difference (Wb - Wa) between the axial thickness Wa of the engaging element 5 and the distance Wb between the pair of restricting surfaces 27a, 27b smaller than in this example. As a result, the amount of axial movement of the engaging element 5 between the pair of restricting portions 18a, 18b can be kept smaller than in this example.

[0094] As long as the engaging element 5 has such a configuration, it can be configured with one engaging element 5 or with two or more engaging elements 5. In this example, the engaging element 5 is configured with two engaging elements 5. Each engaging element 5 has the function of an engaging element 5.

[0095] In the reverse input cutoff clutch 1 of this example, the pressing surfaces 34 of the two engaging elements 5 face radially opposite each other, and the flat surface portions 38 face each other, with each engaging element 5 disposed radially inward of the pressed surface 6 so as to be movable in a first direction. Furthermore, the two input-side engaging portions 13 of the input member 3 disposed on one axial side are axially inserted into the input-side engaged portions 35 of the two engaging elements 5, and the output-side engaging portion 17 of the output member 4 disposed on the other axial side is axially inserted between the output-side engaged portions 36 of the two engaging elements 5. In other words, the output-side engaged portions 36 of the two engaging elements 5 are disposed so as to sandwich the output-side engaging portion 17 from the radially outer side.

[0096] When the two engaging elements 5 are positioned radially inside the pressed surface 6, the inner diameter dimension of the pressed surface 6 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 6 and the pressing surface 34, the area between the output side engaging portion 17 and the output side engaged portion 36, and the area between the tip faces of the convex portions 39.

[0097] Furthermore, when the two engaging elements 5 are positioned radially inward of the pressed surface 6, the widthwise middle portion of the radially inner portion of each engaging element 5 is positioned between a pair of regulating portions 18a, 18b of the output member 4 in the axial direction.

[0098] <Explanation of reverse input cutoff clutch operation> The operation of the reverse input cutoff clutch 1 of this example will be described with reference to Figures 6 and 7. Figures 6 and 7 omit the illustration of the two biasing members 40, and exaggerate the radial gaps between the input member 3 and the output member 4 and the two engaging elements 5.

[0099] In the reverse input cutoff clutch 1 of this example, when a rotational torque is input to the input member 3, the engaging element 5 moves in a direction away from the pressed surface 6, 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.

[0100] That is, when a rotational torque is input to the input member 3, the input-side engaging portion 13 rotates inside the input-side engaged portion 35 in the rotation direction of the input member 3 (counterclockwise in the example of FIG. 6), as shown in FIG. 6. This reduces the gap between the radially inner surface 15 of the input-side engaging portion 13 and the radially inner surface 37 of the input-side engaged portion 35, and brings the radially inner surface 15 of the input-side engaging portion 13 into contact with the radially inner surface 37 of the input-side engaged portion 35.

[0101] When the input member 3 rotates further from this state, the radially inner surface 15 of the input-side engaging portion 13 presses the radially inner surface 37 of the input-side engaged portion 35 radially inward, and the engaging element 5 moves in a direction away from the pressed surface 6. That is, the engaging element 5 moves radially inward based on engagement with the input member 3, and the output-side engaged portion 36 of the engaging element 5 engages with the output-side engaging portion 17 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 36 of the two engaging elements 5 clamp the output-side engaging portion 17 of the output member 4 from both radial sides.

[0102] More specifically, when the output-side engaged portion 36 of the engaging element 5 and the output-side engaging portion 17 engage with each other, the output member 4 rotates so that the intermediate portion in the longitudinal direction of the side surface 24 of the output-side engaging portion 17 is parallel to the output-side engaged portion 36 of the engaging element 5, causing the intermediate portion to abut against the output-side engaged portion 36 without any 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.

[0103] When a rotational torque is reversely input to the output member 4, the engaging element 5 moves in a direction approaching the pressed surface 6, regardless of the rotational direction of the output member 4. Then, 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 rotational torque reversely input to the output member 4 is transmitted to the input member 3, with the remainder blocked.

[0104] 7, the output-side engaging portion 17 rotates relative to the engaging element 5 in the rotation direction of the output member 4 (clockwise in the example of FIG. 7). The output-side engaged portion 36 is pressed radially outward by a portion of the outer peripheral surface of the output-side engaging portion 17 that is closer to the end of the side surface 24 in the longitudinal direction, and the engaging element 5 moves in a direction approaching the pressed surface 6.

[0105] That is, the engaging elements 5 move radially outward based on their engagement with the output member 4, and the pressing surfaces 34 of the engaging elements 5 come into contact with the pressed surface 6 and frictionally engage with the pressed surface 6. 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 34 of the two engaging elements 5 come into contact with the pressed surface 6 and frictionally engage with the pressed surface 6.

[0106] As a result, the rotational torque inputted in reverse 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 inputted in reverse to the output member 4 is transmitted to the input member 3 and the remainder is blocked.

[0107] 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 17 and the pressed member 2 so that the pressing surface 34 of the engaging element 5 does not slide against the pressed surface 6, thereby locking the output member 4.

[0108] 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 17 and the pressed member 2 so that the pressing surface 34 of the engaging element 5 slides against the pressed surface 6, thereby semi-locking the output member 4.

[0109] In the reverse input cutoff clutch 1 of this example, the size of the gap between each component is adjusted to enable the above operation. In particular, when the pressing surface 34 of the engaging element 5 is in contact with the pressed surface 6, a gap is set to exist between the radially inner surface 15 of the input side engaging portion 13 and the radially inner surface 37 of the input side engaged portion 35.

[0110] This prevents the input side engaging portion 13 from blocking the radially outward movement of the engaging element 5 when a rotational torque is input in reverse to the output member 4, and even after the pressing surface 34 comes into contact with the pressed surface 6, the surface pressure acting on the contact point between the pressing surface 34 and the pressed surface 6 changes depending on the magnitude of the rotational torque input in reverse to the output member 4, ensuring that the output member 4 is locked or semi-locked appropriately.

[0111] The reverse input cutoff clutch 1 of this example further includes, as an optional component, a biasing member 40. The biasing member 40 elastically biases the engaging element 5 in a direction in which it approaches the pressed surface 6.

[0112] The biasing member 40 is disposed between the output member 4 and the engaging element 5, or between the two engaging elements 5 when the engaging element 5 is constituted by two engaging elements 5. In this example, the biasing member 40 is constituted by two biasing members 40 disposed between the two engaging elements 5. The shape of the biasing member 40 is not particularly limited as long as it can elastically bias the engaging element 5 in a direction to bring it closer to the pressed surface 6. In this example, the two biasing members 40 are each constituted by a compression coil spring. The compression coil spring constituting each biasing member 40 is held by inserting the protrusions 39 provided on the two engaging elements 5 into both axial sides of the spring.

[0113] In the reverse input cutoff clutch 1 of this example, the two biasing members 40 elastically bias the engagement element 5 in a direction approaching the pressed surface 6. This allows the two pressing surfaces 34 of the engagement element 5 to be kept in contact with the pressed surface 6 except when rotational torque is input to the input member 3. Therefore, when rotational torque is reversely input to the output member 4, the surface pressure at the contact points between the two pressing surfaces 34 of the engagement element 5 and the pressed surface 6 can be quickly increased, and the reverse input cutoff clutch 1 can be switched to a locked or semi-locked state. In short, the reverse input cutoff clutch 1 of this example can ensure good locking performance.

[0114] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIG.

[0115] In the reverse input cutoff clutch 1a of this example, of the pair of restricting portions 18a, 18c provided on the output member 4a, the amount of protrusion (radial height, first direction dimension) and second direction dimension of the restricting portion 18c on the other axial side from the side surface 24 are greater than the amount of protrusion and second direction dimension of the restricting portion 18a on one axial side from the side surface 24. The restricting portion 18c on the other axial side has an end face shape that is generally semicircular or generally fan-shaped when viewed from the axial direction. In other words, in this example, the restricting portion 18c on the other axial side is not provided on the intermediate shaft portion 19a, but is formed by the end portion on one axial side of the output shaft portion 20.

[0116] The regulating portion 18c on the other axial side has a regulating surface 27c on its end face on one axial side that regulates the engagement element 5 from moving in the other axial direction, and also has a butting surface on its end face on the other axial side for butting against the end face on one axial side of the inner ring 30 of the radial rolling bearing 28.

[0117] The other configurations and effects of the second example are the same as those of the first example.

[0118] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to Figures 9 to 11. In a reverse input cutoff clutch 1b of this example, the structures of a biasing member 40a and an intermediate shaft portion 19b of an output member 4b are different from those of the first example.

[0119] In this example, the biasing member 40a is disposed between the engaging element 5 and the output member 4b. Note that the first direction and the second direction of the biasing member 40a refer to the first direction and the second direction of the engaging element 5 when the biasing member 40a is disposed between the engaging element 5 and the output member 4b.

[0120] In this example, the biasing member 40a is made up of a leaf spring elastically sandwiched between the output member 4b and the engaging element 5, and has a pair of support plate portions 45 that engage with both side portions of the engaging element 5 in the second direction (the front-to-back direction in FIG. 9, the left-to-right direction in FIG. 11), and a pair of pressed plate portions 43 that are arranged in portions offset from the engaging element 5 on both axial sides and connect the pair of support plate portions 45 to each other. The pair of pressed plate portions 43 are in elastic contact with tip surfaces 44a of the pair of regulating portions 18a, 18b of the output member 4b that face the pressed surface 6 in the first direction.

[0121] In this example, the pair of support plate portions 45 constitute both end portions of the urging member 40a in the second direction. Each of the pair of support plate portions 45 has a rectangular planar shape when viewed from the first direction, which is the plate thickness direction.

[0122] In this example, the pair of pressed plate portions 43 constitute an intermediate portion of the urging member 40a in the second direction. Each pressed plate portion 43 constitutes the pair of pressed plate portions 43 and connects the axially opposite ends of the base ends, which are the ends of the pair of support plate portions 45 that are closer to each other in the second direction.

[0123] Each pressed plate portion 43 has an intermediate plate portion 46 that forms an intermediate portion in the second direction, and a pair of end plate portions 47 that form opposite end portions in the second direction. The intermediate plate portion 46 has a band-like planar shape that extends in the second direction when viewed from the first direction, which is the plate thickness direction. Each end plate portion 47 that forms the pair of end plate portions 47 bends at an obtuse angle from the opposite end portions in the second direction of the intermediate plate portion 46 toward a side away from the pressed surface 6 in the first direction, extends in a direction away from the pressed surface 6 in the first direction as it extends away from the intermediate plate portion 46 in the second direction, and has a tip portion connected to the axial end portion of the base end portion of the pair of support plate portions 45.

[0124] The distance between the distal ends of the pair of support plate portions 45 that are farther from each other in the second direction, i.e., the length of the urging member 40a in the second direction, is slightly smaller than the distance between the proximal ends of the two protrusions 39 of the engaging element 5. The distance between the proximal ends of the pair of pressed plate portions 43 in the axial direction is slightly larger than the axial thickness of the engaging element 5.

[0125] The biasing member 40a is positioned between the two protrusions 39 of the engaging element 5 in the second direction, thereby restricting displacement in the second direction relative to the engaging element 5; the axial intermediate portions of the pair of support plate portions 45 engage, specifically contact, with the output side engaged portions 36 of the engaging element 5, thereby restricting displacement in the first direction toward the pressed surface 6 relative to the engaging element 5; and the pair of pressed plate portions 43 are positioned in positions that sandwich the radially inner portion of the engaging element 5 from both axial sides, thereby assembling the biasing member 40a to the engaging element 5 in a state in which axial displacement relative to the engaging element 5 is restricted.

[0126] Furthermore, the biasing member 40a is elastically deformed such that the intermediate plate portions 46 constituting each pressed plate portion 43 are pressed by the tip surfaces 44a of the pair of restricting portions 18a, 18b of the output member 4b, and the pair of support plate portions 45 elastically press the output-side engaged portions 36. As a result, the biasing member 40a elastically biases the engaging element 5 in a direction approaching the pressed surface 6.

[0127] In this example, the pair of pressed plate portions 43 of the urging member 40a are in elastic contact with the tip surfaces 44a of the pair of restricting portions 18a, 18b, in other words, the pair of pressed plate portions 43 of the urging member 40a are arranged at positions overlapping the pair of pressed plate portions 43 in the first direction. Therefore, compared to a structure in which the pair of pressed plate portions of the urging member are arranged between the pair of restricting portions 18a, 18b in the axial direction, it is easier to reduce the axial dimension of the reverse input cutoff clutch 1b.

[0128] In this example, only the central portion in the second direction of each pressed plate portion 43 is in elastic contact with the tip surfaces 44a of the pair of restricting portions 18a, 18b.

[0129] That is, in this example, the center in the second direction of the tip surfaces 44a of the pair of restricting portions 18a, 18b is configured as the output-side pressing portion 23 configured as a partially cylindrical surface. Furthermore, both side portions in the second direction of the tip surfaces 44a are configured as inclined surface portions 26 that are inclined in a direction away from the pressed surface 6 in the first direction as they move away from the output-side pressing portion 23 in the second direction. In this example, the center of curvature of the output-side pressing portion 23 coincides with the rotational axis O of the output member 4. However, the center of curvature of the output-side pressing portion 23 may also be an axis that is parallel to the rotational axis O of the output member 4 and is shifted relative to the rotational axis O of the output member 4 closer to the output-side pressing portion 23 or farther from the output-side pressing portion 23 than in this example.

[0130] In this example, only the center in the second direction of the intermediate plate portion 46, which is the center in the second direction of each pressed plate portion 43, is pressed by the output-side pressing portion 23 of the tip surfaces 44a of the pair of restricting portions 18a, 18b. In this example, regardless of the direction in which the output member 4 rotates relative to the engaging element 5, the inclined surface portions 26 of the tip surfaces 44a of the pair of restricting portions 18a, 18b do not come into contact with the pressed plate portion 43.

[0131] That is, in this example, not only when a rotational torque is not reversely input to the output member 4b, but also when a rotational torque is reversely input to the output member 4b, causing the output member 4 to rotate relative to the engaging member 5 in either direction, the elastic contact positions of the tip surfaces 44a of the pair of restricting portions 18a, 18b with the respective pressed plate portions 43 are only at the center in the second direction. Therefore, the pair of support plate portions 45 always press both sides of the engaging member 5 in the second direction with equal force. This effectively prevents moment load from acting on the engaging member 5 from the tip surfaces 44a of the pair of restricting portions 18a, 18b via the biasing member 40a. Therefore, the posture of the engaging member 5 when it moves radially outward can be stabilized, making it easier to appropriately transition to the locked state or the semi-locked state.

[0132] In the reverse input cut-off clutch 1 of this example, the engaging element 5 is also composed of two engaging elements 5, so the biasing member 40a is composed of two biasing members 40a, each arranged between the two engaging elements 5 and the output member 4b, in accordance with the number of engaging elements 5.

[0133] Furthermore, when implementing the present disclosure, the entire tip surface 44a of each can be constructed from a partial cylindrical surface, and the central portion of the partial cylindrical surface in the second direction can be used to press the central portion of each pressed plate portion 43 (intermediate plate portion 46) in the second direction.

[0134] Furthermore, when implementing the present disclosure, each tip surface 44a can be configured as a plane similar to that of the first example, i.e., a plane parallel to the side surface 24, and each pressed plate portion 43 (intermediate plate portion 46) can be pressed from that plane.

[0135] The other configurations and effects of the third example are the same as those of the first example. [Explanation of symbols]

[0136] 1, 1a, 1b Reverse input cutoff clutch 2. Pressurized member 3 Input member 4, 4a, 4b Output member 5 Engagement element 6 Pressed surface 7 Output element 8 Large diameter cylindrical surface 9 Small diameter cylindrical surface part 10 Connection surface 11 Inward flange 12 screw holes 13 Input side engagement portion 14 Input shaft 15 Radial inner surface 16 Radial outer surface 17 Output side engagement portion 18a, 18b, 18c Regulatory Department 19, 19a, 19b Intermediate shaft section 20 Output shaft 21 Small diameter shaft 22 Output flange 23 Output side pressing part 24 Side 25 End face 26 Slope section 27a, 27b, 27c Regulatory aspects 28 Radial Rolling Bearing 29 Outer ring 30 Inner Circle 31 Rolling elements 32a, 32b retaining ring 33 Plain bearings 34 Pressing surface 35 Input side engaged portion 36 Output side engaged part 37 Radial inner surface 38 Flat surface section 39 Convex part 40, 40a biasing member 41 End face 42 Corner R 43 Pressed plate portion 44, 44a Tip surface 45 Support plate part 46 Intermediate plate 47 End plate

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 facing 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 first direction which is a direction in which the pressing surface approaches or moves away from the pressed surface; Equipped with 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 in a direction away from the pressed surface in the first direction, thereby engaging 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 the pressing surface is pressed against the pressed surface, causing the pressing surface to frictionally engage with the pressed surface. The output member has a pair of restricting portions that are integrally formed with the output member and that are arranged at positions that sandwich the engaging element from both sides in the axial direction, and the pair of restricting portions restrict axial movement of the engaging element relative to the output member. Reverse input cut-off clutch.

2. 2. The reverse input cut-off clutch according to claim 1, wherein the pair of regulating portions are provided so as to protrude from portions of the output member adjacent to both axial sides of the output side engaging portion toward a side closer to the pressed surface in the first direction.

3. a biasing member that elastically biases the engaging element in a direction toward the pressed surface, the biasing member is configured by a leaf spring elastically sandwiched between the output member and the engaging element, and has a pair of support plate portions that engage with both side portions of the engaging element in a second direction that is perpendicular to both the axial direction of the pressed surface and the first direction, and a pair of pressed plate portions that are disposed in portions offset from the engaging element on both sides in the axial direction, and each of which connects the pair of support plate portions together, The pair of pressed plate portions elastically contact tip surfaces of the pair of restricting portions that face the pressed surface in the first direction.

3. The reverse input disconnecting clutch according to claim 2.

4. 2. The reverse input cutoff clutch according to claim 1, further comprising a biasing member that elastically biases the engaging element in a direction that brings the engaging element closer to the pressed surface.

5. 5. The reverse input cutoff clutch according to claim 1, wherein the engagement element is configured by two engagement elements.

Images