Reverse input block clutch

Abstract

To provide a reverse input block clutch which can suppress the generation of noise compared with a prior art.SOLUTION: A reverse input block clutch comprises a housing, an input member, an output member, and a pair of engagement pieces 5 having an input-side engaged part 53 which can be engaged with the input member and an output-side engaged part 54 which can be engaged with the output member. The engagement pieces 5 have piece parts 7 which are formed of members different from those of engagement piece main bodies 50. The piece parts 7 are provided in a position corresponding to at least either of the input-side engaged part 53 and the output-side engaged part 54 of the engagement piece 5. The piece parts 7 are formed of cushioning members. Recesses 55, 56 for accommodating the piece parts 7 are formed at the engagement pieces 5. Also, engagement protrusions 57, 58 engaged with the piece parts 7 are provided at the recesses 55, 56.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a reverse input disconnect clutch. [Background technology]

[0002] Conventionally, there is known a configuration of a reverse input cutoff clutch that includes an input member connected to an input mechanism such as a drive source and an output member connected to an output mechanism such as a reducer, and that allows transmission of a rotational force from the input member to the output member while cutting off reverse input of the rotational force from the output member to the input member. Various techniques have been proposed for improving the performance of these reverse input cutoff clutches.

[0003] For example, Patent Document 1 discloses a configuration of a reverse input cutoff clutch having a pressed member having a pressed surface, an input member and an output member provided coaxially with each other on the radial inside of the pressed surface, and a pair of engagement elements interposed between the input member and the output member in a front view and movable in the radial direction. According to the technology described in Patent Document 1, when a rotational force is reversely input to the output member, the engagement between the engagement elements and the output member causes the engagement elements to move in a direction approaching the pressed surface and frictionally engage with the pressed surface, thereby cutting off the rotational force reversely input to the output member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 026794 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned conventional technology, in order to ensure ease of assembly and operability of the reverse input cutoff clutch, a gap is provided between the input member and the engaging element and between the output member and the engaging element in a neutral state in which no rotational force is input to either the input member or the output member. As a result, rattling occurs due to the gap, and there is a risk of noise being generated when rotational torque is input to the input member or the output member.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a reverse input cutoff clutch that can reduce noise generation compared to the prior art. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention proposes the following means. A reverse input cutoff clutch according to a first aspect of the present invention comprises a housing having a pressed surface on an inner circumferential surface, an input member having an input side engaging portion provided radially inward from the pressed surface and arranged coaxially with the axial direction of the pressed surface, an output member having an output side engaging portion arranged radially inward from the pressed surface and radially inward from the input side engaging portion and arranged coaxially with the pressed surface, and a pair of engagers 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 capable of moving relatively to each other in a first direction along the radial direction, wherein the first direction coincides with a direction in which the pair of engagers approach and move away from each other, When a rotational force is input to the input member, the pair of engaging elements move toward each other toward the inside in the first direction based on the engagement between the input side engaging portion and the input side engaged portion, and transmit the rotational force to the output member based on the engagement between the output side engaging portion and the output side engaged portion.When a rotational force is input in reverse to the output member, the pair of engaging elements move away from each other toward the outside in the first direction based on the engagement between the output side engaging portion and the output side engaged portion, frictionally engaging the pressed surface and the pressing surface. A piece portion formed of a separate material from the engaging elements is provided at a position of the engaging elements corresponding to at least one of the input side engaged portion and the output side engaged portion. Effect of the Invention

[0008] According to the reverse input cutoff clutch of the present invention, it is possible to provide a reverse input cutoff clutch that can reduce noise generation compared to the prior art. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view of the reverse input cut-off clutch according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a perspective view of an engagement element, an elastic member, and a piece portion according to the first embodiment in a combined state. [Figure 4]FIG. 4 is an exploded perspective view of one of the engagement elements and a piece portion according to the first embodiment. [Diagram 5] 13 is an explanatory diagram showing the positional relationship between an input member, an engagement element, and a piece portion according to the second embodiment before they come into contact with each other. FIG. [Figure 6] 13 is an explanatory diagram showing the positional relationship between an input member, an engagement element, and a piece portion according to the second embodiment at the time of low torque. FIG. [Figure 7] 13 is an explanatory diagram showing the positional relationship among an input member, an engagement element, and a piece portion according to the second embodiment when a high torque is applied. FIG. [Figure 8] 13 is an explanatory diagram showing the positional relationship between an output member, an engagement element, and a piece portion according to the second embodiment before they come into contact with each other. FIG. [Figure 9] FIG. 11 is an explanatory diagram showing the positional relationship among an output member, an engagement element, and a piece portion according to the second embodiment at the time of low torque. [Figure 10] FIG. 11 is an explanatory diagram showing the positional relationship among an output member, an engagement element, and a piece portion according to the second embodiment when high torque is applied. [Figure 11] 13 is an explanatory diagram showing the positional relationship between the output member, the engagement element, and the piece portion before contact with each other when a reverse input is applied in the second embodiment. FIG. [Figure 12] FIG. 11 is an explanatory diagram showing the positional relationship among the output member, the engagement element, and the piece portion at low torque when a reverse input is applied in the second embodiment. [Figure 13] FIG. 11 is an explanatory diagram showing the positional relationship among the output member, the engagement element, and the piece portion when a reverse input is applied in the second embodiment and a high torque is applied. [Figure 14] FIG. 11 is a perspective view of a reverse input cutoff clutch according to a third embodiment. [Figure 15] 15 is a cross-sectional view taken along line XV-XV in FIG. 14 . [Figure 16] Enlarged view of XVI in Figure 15. [Figure 17] FIG. 13 is a cross-sectional view of one of the engagement pieces and a piece portion according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the center axis C of the reverse input cutoff clutch 1, unless otherwise specified.

[0011] (First embodiment) (Reverse input cutoff clutch) Fig. 1 is a cross-sectional view of a reverse input cutoff clutch 1 according to a first embodiment. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. 1 and 2, the reverse input cutoff clutch 1 includes an input member 2, an output member 3, a housing 4, a pair of engagers 5, and an elastic member 6. The reverse input cutoff clutch 1 transmits the rotational force input to the input member 2 to the output member 3. Meanwhile, the reverse input cutoff clutch 1 has a reverse input cutoff function of cutting off the rotational force reversely input to the output member 3 and not transmitting it to the input member 2, or of transmitting only a portion of the rotational force to the input member 2 and cutting off the remainder.

[0012] (Input member) The input member 2 is connected to an input mechanism such as an electric motor (not shown). A rotational force from the input mechanism is input to the input member 2. The input member 2 has an input shaft body 21 and a pair of arms 23. The input shaft body 21 is provided on the input mechanism side in the axial direction. The input shaft body 21 is formed in a columnar (or cylindrical) shape centered on a central axis C. In the following description, the side of the input member 2 connected to the input mechanism may be referred to as a first axial side, and the opposite side may be referred to as a second axial side.

[0013] The pair of arms 23 extend from the input shaft body 21 toward the second side in the axial direction. The arms 23 are integrally formed with the input shaft body 21. The arms 23 are provided in pairs at both radial ends of the input shaft body 21. Thus, the arms 23 are provided at a position slightly offset radially outward from the input shaft body 21. As shown in FIG. 2, the arms 23 are formed in a trapezoid shape with one side curved when viewed from the axial direction. The arms 23 have an input side engaging portion 25 facing radially inward, a curved surface portion 26 facing radially outward, and two side surface portions 27 connecting the ends of the input side engaging portion 25 and the curved surface portion 26. The curved surface portion 26 is formed in an arc shape centered on the central axis C.

[0014] A plurality of arm portions 23 are provided in accordance with the number of engaging elements 5 described below. In this embodiment, a pair of arm portions 23 is provided in accordance with the provision of a pair of engaging elements 5. The number of arm portions 23 is not limited to two, and the number of arm portions 23 may be one, or three or more, in accordance with the number of engaging elements 5.

[0015] (Output component) As shown in Fig. 1, the output member 3 is connected to an output mechanism such as a reducer (not shown), and outputs a rotational force (rotational torque). The output member 3 is arranged coaxially with the input member 2. As shown in Figs. 1 and 2, the output member 3 has an output shaft body 31 and an insertion portion 32. The output shaft body 31 is provided on a second side in the axial direction. The output shaft body 31 is formed in a columnar (or cylindrical) shape centered on the central axis C.

[0016] The insertion portion 32 extends from an end portion on a first side in the axial direction of the output shaft body 31 toward the first side in the axial direction. The insertion portion 32 is integrally formed with the output shaft body 31. The insertion portion 32 is a portion inserted between a pair of engaging elements 5 described later, and is disposed radially inward from a pair of arm portions 23 of the input member 2. In this embodiment, the base end portion of the insertion portion 32 inserted between the pair of engaging elements 5 (for example, a portion located on the second side in the axial direction from a retaining ring 39 (see FIG. 1)) is formed in a plate shape. The shape of the base end portion of the insertion portion 32 is not limited to a plate shape. The tip portion of the insertion portion 32 (for example, a portion located on the first side in the axial direction from the retaining ring 39) is formed in a cylindrical shape. The tip portion of the insertion portion 32 is fitted to the input member 2 via a bearing 46 so as to be relatively rotatable. The bearing 46 is, for example, a rolling bearing or a sliding bearing. The outer peripheral surface of the base end of the insertion portion 32 has a pair of output side engagement portions 35 facing both sides in the thickness direction of the insertion portion 32 (the up and down direction in Figure 2), and a pair of side portions 36 connecting the ends of the pair of output side engagement portions 35.

[0017] 2, each output-side engaging portion 35 is formed of a flat surface perpendicular to the minor axis direction of the insertion portion 32. Each output-side engaging portion 35 faces a pair of engaging elements 5. The output-side engaging portion 35 is provided radially inward of the input-side engaging portion 25 of the input member 2. A pair of side portions 36 connect both ends of the output-side engaging portion 35 to each other.

[0018] The insertion portion 32 has a plurality of output side engaging portions 35 and side surface portions 36 provided in accordance with the number of engaging elements 5 described below. In this embodiment, a pair of output side engaging portions 35 and side surface portions 36 are provided in accordance with the provision of a pair of engaging elements 5. The number of output side engaging portions 35 is not limited to two, and the number of output side engaging portions 35 may be one, or three or more, in accordance with the number of engaging elements 5.

[0019] (housing) The housing 4 is formed in a cylindrical shape. The housing 4 is fixed to another member (not shown) and its rotation is restricted. The housing 4 is arranged coaxially with the input member 2 and the output member 3. The housing 4 accommodates the input member 2, the output member 3, and a pair of engagement elements 5. The housing 4 has a first accommodation hole 41, a second accommodation hole 42, and a pressed surface 40.

[0020] As shown in FIG. 1 , the first accommodating hole 41 penetrates the housing 4 in the axial direction. The first accommodating hole 41 is formed coaxially with the central axis C. The first accommodating hole 41 is provided on a second axial side of the housing 4. The output shaft body 31 of the output member 3 is accommodated inside the first accommodating hole 41. The inner diameter of the first accommodating hole 41 is larger than the outer shape of the output shaft body 31 of the output member 3. The first accommodating hole 41 rotatably holds the output member 3 via a bearing 45.

[0021] The second accommodating hole 42 penetrates the housing 4 in the axial direction. The second accommodating hole 42 is formed coaxially with the central axis C. The second accommodating hole 42 is provided on the first side in the axial direction with respect to the first accommodating hole 41. The inner diameter of the second accommodating hole 42 is larger than the inner diameter of the first accommodating hole 41. The arm portion 23 of the input member 2 is accommodated inside the second accommodating hole 42. The insertion portion 32 of the output member 3 is accommodated inside the second accommodating hole 42 and further inside the arm portion 23. The inner diameter of the second accommodating hole 42 is larger than the outer shape of the pair of arm portions 23 of the input member 2. The input member 2 is accommodated inside the second accommodating hole 42 so as to be rotatable relative to the housing 4.

[0022] The inner circumferential surface of the second accommodating hole 42 serves as a pressed surface 40. The pressed surface 40 is formed so as to be coaxial with the central axis C. The pressed surface 40 is provided so as to be coaxial with the input member 2 and the output member 3. An input side engaging portion 25 of the input member 2 and an output side engaging portion 35 of the output member 3 are provided radially inside the pressed surface 40.

[0023] (engager) Fig. 3 is a perspective view of the engagement piece 5, the elastic member 6, and the piece 7 according to the first embodiment in a combined state. Fig. 4 is an exploded perspective view of one of the engagement pieces 5 and the piece 7 according to the first embodiment. As shown in Figs. 2 to 4, the pair of engaging elements 5 are configured in a semicircular shape and are disposed radially inward of the housing 4. The pair of engaging elements 5 are configured to be movable toward and away from each other in a first direction D1 along the radial direction. The first direction D1 is a direction along the radial direction of the housing 4, and is a direction in which the pair of engaging elements 5 face each other. A direction perpendicular to each of the axial direction and the first direction D1 may be referred to as a second direction D2. Of the first direction D1 and the second direction D2, the directions facing radially outward may be referred to as the outside of the first direction D1 and the outside of the second direction D2. Each of the pair of engaging members 5 has a pressing surface 51, a bottom surface 52, an input side engaged portion 53, an output side engaged portion 54, at least one or more recesses 55, 56, at least one or more engaging protrusions 57, 58, and at least one or more link portions 7.

[0024] The pressing surface 51 is a radially outer surface that presses the pressed surface 40 of the housing 4, and is a convex surface in the shape of a circular arc. A part of the outer circumferential surface of the engaging element 5 that faces the pressed surface 40 may be the pressing surface 51. The pressing surface 51 presses the pressed surface 40 when the reverse input cutoff clutch 1 is in a locked state (a state in which the reverse input from the output member 3 is cut off). The radius of curvature of the pressing surface 51 is equal to or smaller than the radius of curvature of the pressed surface 40. Two pressing surfaces 51 are provided for each engaging element 5, and are formed so that the frictional engagement force between the engaging element 5 and the pressed surface 40 is increased by the wedge effect. The two pressing surfaces 51 are provided at positions spaced apart from each other in the circumferential direction of the engaging element 5. The pressing surface 51 may be directly formed by the entire or part of the outer circumferential surface of the engaging element 5, or may be formed to have a surface property with a larger friction coefficient than the other parts of the engaging element 5. For example, the pressing surface 51 may be formed of a friction material fixed to the engaging element 5 by sticking or bonding. Each pressing surface 51 of the engaging element 5 faces the inner side of the housing 4 in the radial direction.

[0025] The bottom surface 52 of the engaging element 5 is provided radially inward from the pressing surface 51. The bottom surface 52, together with an output-side engaged portion 54 of the engaging element 5, which will be described in detail later, forms a straight portion of the semicircular engaging element 5. In this embodiment, the bottom surface 52 is formed in a substantially flat surface shape except for a pair of protrusions 59 and an output-side recess 56, which will be described later. The bottom surfaces 52 of the pair of engaging elements 5 face each other in the radial direction. The inner diameter dimension of the pressed surface 40 and the outer dimensions of the engaging elements 5 are set so that, when the pair of engaging elements 5 are positioned radially inside the housing 4, a gap exists between the pressed surface 40 and the pressing surface 51, and at least one of the gaps exists between the pair of bottom surfaces 52 and the output member 3.

[0026] The input side engaged portion 53 is a hole that penetrates the center of the engaging element 5 in the axial direction in a front view. The input side engaged portion 53 is formed in the shape of a long hole that is long in the second direction D2. The arm portion 23 of the input member 2 is inserted into the input side engaged portion 53. The input side engaged portion 53 engages with the arm portion 23. The input side engaged portion 53 has a size that allows the arm portion 23 of the input member 2 to be loosely inserted. Specifically, the input side engaged portion 53 is formed so that a gap exists between the arm portion 23 and the inner peripheral surface of the input side engaged portion 53 when the arm portion 23 of the input member 2 is inserted inside the input side engaged portion 53. Therefore, in the neutral state, the arm portion 23 can be slightly displaced in the rotation direction of the input member 2 relative to the input side engaged portion 53 (i.e., the engaging element 5), and the engaging element 5 can be slightly displaced in the first direction D1 relative to the arm portion 23. A piece portion 7, which will be described in detail later, is provided in a portion of the input side engaged portion 53 that contacts the input member 2. By attaching the piece portion 7 to the engaging element main body 50, at least a part of the input side engaged portion 53 is formed.

[0027] The output side engaged portion 54 is a portion of the straight portion (bottom surface 52) of the engaging element 5 formed in a semicircular shape, located near the center in the second direction D2. The output side engaged portion 54 is provided radially inward (first direction D1) from the input side engaged portion 53. The output side engaged portion 54 is engaged with the insertion portion 32 of the output member 3. At least a portion of the output side engaged portion 54 is formed by attaching the piece portion 7, which will be described in detail later, to the engaging element main body 50. With the piece portion 7 attached to the engaging element main body 50, the output side engaged portion 54 has a flat surface shape that is continuous with the bottom surface 52.

[0028] 2 and 3, a convex portion 59 is integrally formed on the bottom surface 52 of the engaging element 5 so as to protrude from the bottom surface 52 of the engaging element 5 toward the other engaging element 5. A pair of convex portions 59 are provided on the bottom surface 52 of the engaging element 5 and spaced apart in the second direction D2. The pair of convex portions 59 are provided inward from the extreme end of the bottom surface 52 and outward from the output-side engaged portion 54 in the second direction D2. In this embodiment, the convex portion 59 is formed in a quadrangular prism shape with the height direction being the first direction D1.

[0029] The protruding height of the convex portion 59 is set to a height such that, for example, when the engaging element 5 is in an unlocked state (a state in which transmission of rotational force from the input member 2 to the output member 3 is permitted), the convex portions 59 of a pair of engaging elements 5 facing each other in the first direction D1 face each other with a gap in the first direction D1.

[0030] 1 and 2, in a state in which the reverse input cutoff clutch 1 is assembled, the arm portion 23 of the input member 2 is axially inserted into each of the input side engaged portions 53 of the pair of engagers 5, and the insertion portion 32 of the output member 3 is axially inserted between the output side engaged portions 54 of the pair of engagers 5. In other words, the pair of engagers 5 are disposed so that the output side engaged portions 54 sandwich the insertion portion 32 of the output member 3 from the radially outer side.

[0031] 1, end plates 38 for positioning each member in the axial direction are provided on both axial sides of the engaging element 5. Furthermore, a retaining ring 39 for positioning each member is provided on a first axial side of the engaging element 5. In addition to the positioning function, components such as end plates 38 may be provided to have a function of preventing contact between the engaging element 5 and the output member 3 and the input member 2, for example, to suppress wear.

[0032] As shown in Fig. 4, the recesses 55, 56 are formed so as to be recessed inwardly of the engaging element main body 50. In this embodiment, two recesses are provided for one engaging element 5. In the following description, one of the two recesses may be referred to as the input side recess 55, and the other as the output side recess 56. When there is no need to distinguish between these, they may be simply referred to as the recesses 55, 56.

[0033] The input side recess 55 is recessed from the input side engaged portion 53 toward the bottom surface 52 in the first direction D1. In a state in which the engaging element 5 and the input member 2 are combined, the input side recess 55 is provided at a position corresponding to the input member 2 in the second direction D2. The input side recess 55 is formed so as to penetrate the engaging element body 50 in the axial direction. This makes it possible to form the input side recess 55, for example, by pressing from the axial direction. When viewed from the axial direction, the outer shape of the input side recess 55 is formed so that the width in the second direction D2 increases as it moves from the outside (the pressing surface 51 side) to the inside (the bottom surface 52 side) in the first direction D1 (see also FIG. 2). In other words, the cross-sectional area of ​​the input side recess 55 perpendicular to the depth direction at a first position in the depth direction (first direction D1) of the input side recess 55 is larger than the cross-sectional area of ​​the input side recess 55 perpendicular to the depth direction at a second position that is shallower than the first position.

[0034] The output side recess 56 is recessed from the bottom surface 52 of the engaging element 5 toward the pressing surface 51 side in the first direction D1. In a state in which the engaging element 5 and the output member 3 are combined, the output side recess 56 is provided at a position corresponding to the output member 3 in the second direction D2. The output side recess 56 is formed to penetrate the engaging element body 50 in the axial direction. This makes it possible to form the output side recess 56, for example, by pressing from the axial direction, similar to the input side recess 55. When viewed from the axial direction, the outer shape of the output side recess 56 is formed so that the width in the second direction D2 increases as it moves from the inside (bottom surface 52 side) to the outside (pressing surface 51 side) in the first direction D1 (see also FIG. 2). That is, similar to the input side recess 55, the cross-sectional area of ​​the output side recess 56 perpendicular to the depth direction at a first position in the depth direction (first direction D1) of the output side recess 56 is larger than the cross-sectional area of ​​the output side recess 56 perpendicular to the depth direction at a second position shallower than the first position.

[0035] The input-side recess 55 and the output-side recess 56 thus formed are formed to have a depth such that their respective bottoms do not communicate with each other in the first direction D1. In this embodiment, the width dimension of the output-side recess 56 in the second direction D2 is larger than the width dimension of the input-side recess 55 in the second direction D2.

[0036] The engagement protrusions 57, 58 are provided in the above-mentioned recesses 55, 56, respectively. That is, in this embodiment, two engagement protrusions are provided for one engagement piece 5. In the following description, of the two engagement protrusions, the one provided corresponding to the input side recess 55 may be referred to as the input side engagement protrusion 57, and the one provided corresponding to the output side recess 56 may be referred to as the output side engagement protrusion 58. When there is no need to distinguish between these, they may be simply referred to as the engagement protrusions 57, 58.

[0037] The input side engagement protrusion 57 protrudes from the bottom of the input side recess 55 toward the pressing surface 51 in the first direction D1. The input side engagement protrusion 57 is provided at approximately the center of the input side recess 55 in the second direction D2. The input side engagement protrusion 57 is formed, for example, in a rectangular prism shape with the height direction being in the first direction D1. As shown in FIG. 4, the width dimension W1 of the input side engagement protrusion 57 along the axial direction is smaller than the thickness dimension T1 of the engagement element main body 50 along the axial direction. Therefore, both ends of the input side engagement protrusion 57 in the axial direction are located inside the end faces of the engagement element main body 50 facing the axial direction.

[0038] The output side engagement protrusion 58 protrudes from the bottom of the output side recess 56 toward the other engagement element 5 in the first direction D1. The output side engagement protrusion 58 is provided at approximately the center of the output side recess 56 in the second direction D2. The output side engagement protrusion 58 is formed, for example, in a rectangular prism shape with the first direction D1 as the height direction. As with the input side engagement protrusion 57, the width dimension W2 of the output side engagement protrusion 58 along the axial direction is smaller than the thickness dimension T1 of the engagement element main body 50 along the axial direction. Therefore, both ends of the output side engagement protrusion 58 in the axial direction are located inside the end face of the engagement element main body 50 facing the axial direction. The width dimension W1 and the width dimension W2 may be equal to or different from each other.

[0039] As shown in Figs. 2 to 4, the piece portions 7 are housed in the recesses 55, 56 described above. In this embodiment, two piece portions 7 are provided for one engagement piece 5. One of the two piece portions 7 may be referred to as an input side piece portion 71, and the other as an output side piece portion 72. When there is no need to distinguish between them, they may be simply referred to as piece portions 7. In this embodiment, the piece portions 7 are provided at positions corresponding to both the input side engaged portion 53 and the output side engaged portion 54.

[0040] The input-side piece 71 is accommodated in the input-side recess 55. The input-side piece 71 engages with the input-side engagement protrusion 57 in a state accommodated in the input-side recess 55 (hereinafter, sometimes referred to as an accommodated state). Specifically, the input-side piece 71 has a pair of main bodies 71a arranged outside the input-side engagement protrusion 57 in the second direction D2, and a pair of connecting parts 71b connecting the pair of main bodies 71a to each other. The main bodies 71a are formed in a shape (e.g., rectangular) equivalent to the bottom of the input-side recess 55 on both sides of the input-side engagement protrusion 57 when viewed from the first direction D1. The connecting parts 71b connect both ends of the main bodies 71a in the axial direction to each other. The input-side engagement protrusion 57 is inserted into a central space surrounded by the pair of main bodies 71a and the pair of connecting parts 71b. In this embodiment, the shape of the outer periphery of the input-side piece 71 is equivalent to the shape of the inner periphery of the input-side recess 55. That is, in the accommodated state, the external shape of the input-side piece 71 is formed such that the width in the second direction D2 increases toward the bottom side of the input-side recess 55 in the first direction D1. Therefore, when the input-side piece 71 is attached, the input-side piece 71 is accommodated in the input-side recess 55 while being elastically deformed.

[0041] As shown in Figs. 3 and 4, the input-side piece 71 is pushed into the input-side recess 55 formed in the engaging element 5 along the first direction D1 from the input-side engaged portion 53 side, so that the input-side piece 71 is accommodated in the input-side recess 55. At this time, the input-side piece 71 is provided at a position corresponding to the input member 2, so that at least a part of the input-side piece 71 functions as the input-side engaged portion 53. In the accommodated state of the piece 7 (see Figs. 2 and 3), the upper surface of the input-side piece 71 facing outward in the first direction D1 and the upper surface of the part of the input-side engaged portion 53 where the input-side recess 55 is not formed are substantially flush with each other. In the accommodated state, the top of the input-side engaging protrusion 57 is located at a lower position than the upper surface of the input-side piece 71. In addition, in the accommodated state, the surfaces of the input-side piece 71 facing both sides in the axial direction and the surfaces of the engaging element 5 (engagement element main body 50) facing both sides in the axial direction are flush with each other. In this embodiment, the input side engagement portion 25 of the input member 2 always contacts the engagement element 5 (engagement element main body 50) via the input side piece portion 71. In other words, the rotational force input to the input member 2 is transmitted to the engagement element 5 via the input side piece portion 71, and the input side engagement portion 25 and the engagement element main body 50 are formed not to come into direct contact with each other.

[0042] As shown in FIG. 2 to FIG. 4, the output-side piece 72 is accommodated in the output-side recess 56. The output-side piece 72 engages with the output-side engagement protrusion 58 in a state accommodated in the output-side recess 56 (hereinafter, sometimes referred to as an accommodated state). Specifically, the output-side piece 72 has a pair of main bodies 72a disposed outside the output-side engagement protrusion 58 in the second direction D2, and a pair of connecting parts 72b connecting the pair of main bodies 72a to each other. The main bodies 72a are formed in a shape (e.g., rectangular) equivalent to the bottom of the input-side recess 55 on both sides of the input-side engagement protrusion 57 when viewed from the first direction D1. The connecting parts 72b connect both ends of the main bodies 72a in the axial direction to each other. The output-side engagement protrusion 58 is inserted into the central space surrounded by the pair of main bodies 72a and the pair of connecting parts 72b. In this embodiment, the shape of the outer periphery of the output-side piece 72 is equivalent to the shape of the inner periphery of the output-side recess 56. That is, in the accommodated state, the outer shape of the output-side piece 72 is formed such that the width in the second direction D2 increases toward the bottom side of the output-side recess 56 in the first direction D1. Therefore, when the output-side piece 72 is attached, the output-side piece 72 is accommodated in the output-side recess 56 while being elastically deformed.

[0043] As shown in Figs. 3 and 4, the output-side piece 72 is pushed into the output-side recess 56 formed in the engaging member 5 from the bottom surface 52 side along the first direction D1, so that the output-side piece 72 is accommodated in the output-side recess 56. At this time, the output-side piece 72 is provided at a position corresponding to the output member 3, so that at least a part of the output-side piece 72 functions as the output-side engaged portion 54. In the accommodated state of the piece 7 (see Fig. 3), the lower surface of the output-side piece 72 facing the inside in the first direction D1 and the lower surface of the part of the bottom surface 52 where the input-side recess 55 is not formed are substantially flush with each other. In the accommodated state, the top of the output-side engaging protrusion 58 is located at a height position recessed from the lower surface of the output-side piece 72. In the accommodated state, the surfaces of the output-side piece 72 facing both sides in the axial direction and the surfaces of the engaging member 5 (engaging member main body 50) facing both sides in the axial direction are flush with each other. In this embodiment, the output-side engagement portion 35 of the output member 3 always contacts the engagement element 5 (engagement element main body 50) via the output-side piece portion 72. In other words, the rotational force reversely input to the output member 3 is transmitted to the engagement element 5 via the output-side piece portion 72, and the output-side engagement portion 35 and the engagement element main body 50 are formed so as not to come into direct contact with each other.

[0044] Each of the above-mentioned pieces 7 is formed of a separate member from the engaging body 50. In this embodiment, the piece 7 is formed of a shock-absorbing material. Examples of the shock-absorbing material include elastic materials such as rubber or resin that are resistant to grease, and foamed materials that absorb shocks by using an air layer. In the present embodiment, the bridge portion 7 is a cushioning member, but the present invention is not limited to this. For example, the bridge portion 7 may be made of a metal base material, and the surface portion that comes into contact with at least one of the input member 2 and the output member 3 in the housed state may be surface-treated.

[0045] (Elastic material) 2 and 3, the elastic member 6 is arranged so as to be elastically sandwiched between the engaging element 5 and the output member 3. The elastic member 6 is, for example, a leaf spring. The elastic member 6 is provided so as to be able to bias the engaging element 5 outward in the radial direction (first direction D1), i.e., in a direction approaching the pressed surface 40 (see FIG. 2). Specifically, the elastic member 6 is formed so as to be deformable by being sandwiched between the engaging element 5 and the output member 3 and receiving a load, and biases the engaging element 5 outward in the first direction D1 by a restoring force when it is deformed. For example, the elastic member 6 is formed so as to always bias the engaging element 5.

[0046] The elastic member 6 is formed in a flat plate shape as a whole. When the elastic member 6 is sandwiched between the engaging element 5 and the output member 3, the width dimension of the elastic member 6 along the axial direction is larger than the thickness dimension T1 (see FIG. 4) of the engaging element 5 along the axial direction. As shown in FIG. 3, the elastic member 6 is formed with one through hole 62 and a pair of notches 61. The through hole 62 is provided in the approximate center of the elastic member 6 and penetrates the elastic member 6 in the thickness direction. The through hole 62 is formed in a rectangular shape that is slightly smaller than the outer shape of the elastic member 6 in a plan view. The width dimension of the through hole 62 along the axial direction is slightly larger than the thickness dimension T1 of the engaging element 5 along the axial direction. Therefore, at least a part of the engaging element 5 can enter the through hole 62.

[0047] The pair of notches 61 are formed so as to be recessed from both sides in the longitudinal direction of the elastic member 6 (the second direction D2 in a state where it is sandwiched between the engagement element 5 and the output member 3) toward the inside of the elastic member 6. A pair of protrusions 59 of the engagement element 5 fit into the pair of notches 61, respectively. By disposing the elastic member 6 between the pair of protrusions 59 of the engagement element 5, movement of the elastic member 6 in the second direction D2 and the axial direction is restricted.

[0048] (Reverse input cutoff clutch operation) Next, the operation of the reverse input cutoff clutch 1 of this embodiment will be described with reference to FIG. First, when a rotational force is input from the input mechanism to the input member 2, the arm 23 of the input member 2 rotates in the rotational direction of the input member 2 (for example, counterclockwise) around the central axis C. Then, the boundary portion (see point P1) between the input side engaging portion 25 and the side surface portion 27 of the arm 23 presses the inner surface of the input side engaged portion 53 radially inward, and moves the pair of engaging elements 5 in a direction away from the pressed surface 40. In other words, the pair of engaging elements 5 move toward each other radially inward as the rotational force from the input member 2 acts via the input side engaged portion 53. As a result, the bottom surfaces 52 of the pair of engaging elements 5 move toward each other, and the pair of output side engaged portions 54 hold the insertion portion 32 of the output member 3 from both radial sides.

[0049] As a result, the output side engaging portion 35 of the insertion portion 32 in the output member 3 and the bottom surface 52 of the engaging element 5 become parallel to each other, and the insertion portion 32 and the pair of output side engaged portions 54 are engaged without any rattling. Therefore, the rotational force input to the input member 2 is transmitted to the output member 3 via the pair of engaging elements 5 and is output from the output member 3. The same operation is performed when the input member 2 is rotated clockwise.

[0050] Next, a case where a rotational force is input from the output mechanism to the output member 3 will be described. When a rotational force is input to the output member 3 in a reverse direction, the insertion portion 32 of the output member 3 rotates in the rotational direction of the output member 3 (for example, counterclockwise) inside the pair of output side engaged portions 54. Then, the boundary portion (see point P2) between the output side engaging portion 35 and the side surface portion 36 of the insertion portion 32 presses the output side engaged portion 54 radially outward. In addition, due to the restoring force generated in the elastic member 6 sandwiched between the insertion portion 32 and the output side engaged portion 54, the elastic member 6 presses the output side engaged portion 54 of the engaging element 5 further radially outward. This causes the pair of engaging elements 5 to move in a direction approaching the pressed surface 40. That is, the pair of engaging elements 5 move radially outward so as to move away from each other based on the engagement between the output member 3 and the output side engaged portion 54. As a result, the pressing surface 51 of each of the pair of engagement members 5 is pressed against the pressed surface 40 of the housing 4. At this time, the pressing surface 51 and the pressed surface 40 are frictionally engaged over the entire range or at least a portion of the circumferential direction of the pressing surface 51.

[0051] As a result, the rotational force input in reverse to the output member 3 is either completely blocked by being transmitted to the housing 4 fixed to another member (not shown) and not transmitted to the input member 2, or only a portion of the rotational force input in reverse to the output member 3 is transmitted to the input member 2 and the remainder is blocked.

[0052] In the reverse input cutoff clutch 1 of this embodiment, the size of the gap between each of the components is adjusted so that the above-mentioned operation is possible. For example, in a state (locked state) in which the pressing surface 51 of the engaging element 5 contacts the pressed surface 40 due to a reverse input of a rotational force to the output member 3, the input member 2 is located in a neutral position. The neutral position of the input member 2 is a position in which the input side engaging portion 25 of the arm portion 23 is parallel to the input side engaged portion 53. In other words, a gap is provided between the input side engaging portion 25 of the arm portion 23 and the inner surface of the input side engaged portion 53, which allows the pressing surface 51 to press the pressed surface 40 based on the boundary portion (point P2) of the insertion portion 32 of the output member 3 pressing the output side engaged portion 54. This prevents the engaging element 5 from moving radially outward by the arm portion 23 when a rotational force is reversely input to the output member 3. Furthermore, even after the pressing surface 51 comes into contact with the pressed surface 40, the surface pressure acting on the contact portion between the pressing surface 51 and the pressed surface 40 changes according to the magnitude of the rotational force input in reverse to the output member 3, thereby ensuring that the output member 3 is locked or semi-locked appropriately.

[0053] (Action, effect) According to the reverse input cutoff clutch 1 of this embodiment, a piece portion 7 formed of a separate member from the engaging element 5 is provided at a position corresponding to at least one of the input side engaged portion 53 and the output side engaged portion 54 of the engaging element 5. By providing the piece portion 7 formed of a separate member from the engaging element 5, when a rotational torque is input to the input member 2 or the output member 3, the force of contact between the engaging element 5 and the input member 2 or the output member 3 is reduced (absorbed) by the piece portion 7. Therefore, compared to the conventional technology in which an engaging element is formed without providing a piece portion, even if a gap S is provided between the engaging element 5 and the input member 2 or the output member 3 in the neutral state, the generation of contact noise caused by rattling when the engaging element 5 comes into contact with the input member 2 or the output member 3 can be suppressed. Therefore, it is possible to provide a reverse input cutoff clutch 1 that can reduce noise generation compared to the prior art.

[0054] Since the piece portion 7 is made of a buffer material, it is possible to more effectively reduce the force of contact between the input member 2 or the output member 3 and the engagement piece 5. Therefore, it is possible to provide the reverse input cutoff clutch 1 which further suppresses noise generation compared to the conventional technology.

[0055] The piece 7 may be surface-treated on a portion (surface) that contacts the input member 2 or the output member 3. The surface treatment is performed, for example, to reduce the contact noise between the input member 2 or the output member 3 and the engagement member 5. In this case, even if the piece 7 is made of a relatively hard material such as metal or resin, the generation of the contact noise can be suppressed compared to the conventional technology in which the input member 2 or the output member 3 and the engagement member 5 are in direct contact with each other. In addition, since the piece 7 can be made of a relatively hard material, the force transmission loss between the input member 2 or the output member 3 and the engagement member 5 can be reduced. In addition, the strength of the entire engagement member 5 including the piece 7 can be increased. Therefore, the freedom of material selection for the piece 7 can be increased, and the versatility of the reverse input cutoff clutch 1 can be improved.

[0056] The reverse input cutoff clutch 1 has an elastic member 6, which biases the engaging element 5 outward in the first direction D1 so that the engaging element 5 approaches the pressed surface 40. Therefore, the biasing force of the elastic member 6 can suppress the occurrence of rattle caused by the gap between the components. This can suppress the occurrence of noise and vibration caused by rattle. In addition, since the elastic member 6 biases the engaging element 5 outward in the radial direction, when a rotational force is input in reverse from the output member 3, the engaging element 5 is more likely to move outward in the radial direction. This can more reliably lock the rotation of the engaging element 5 when a rotational force is input in reverse. By using the piece portion 7 and the elastic member 6 in combination, rattle between the components can be suppressed, and the occurrence of noise (contact sound) can be further suppressed.

[0057] The piece portion 7 is accommodated in the recesses (the input side recess 55 and the output side recess 56) formed in the engaging element 5. This makes it possible to prevent the engaging element 5 from becoming large due to the provision of the piece portion 7. In addition, the recesses 55, 56 in which the piece portion 7 is accommodated are formed so that the cross-sectional area increases from the shallow side to the deep side in the depth direction. This makes it possible to make it difficult for the piece portion 7 accommodated in the recesses 55, 56 to come off from the recesses 55, 56. When accommodating the piece portion 7, for example, the piece portion 7 can be elastically deformed and pushed into the recesses 55, 56, so that the piece portion 7 can be easily accommodated in the recesses 55, 56. This makes it possible to prevent the engaging element 5 from becoming large, and to stably install the piece portion 7.

[0058] The recesses 55, 56 are provided with engagement protrusions (input side engagement protrusion 57 and output side engagement protrusion 58) that engage with the piece 7. This makes it more difficult for the piece 7 to come off the recesses 55, 56. Therefore, the piece 7 can be stably installed.

[0059] The recesses 55, 56 are formed so as to be recessed from the engaging element 5 along the first direction D1. This allows the piece portion 7 to be provided along the surface of the engaging element 5 facing the input member 2 or the output member 3. This allows the input member 2 or the output member 3 to be in contact with the piece portion 7 reliably. In addition, the size of the engaging element 5 in the axial direction can be prevented from increasing. In addition, by changing the thickness of the piece portion 7, the contact state between the input member 2 or the output member 3 and the piece portion 7 can be adjusted. For example, when the thickness of the piece portion 7 along the first direction D1 is increased, the reverse input cutoff clutch 1 can be formed so that the input member 2 or the output member 3 and the engaging element 5 are always in indirect contact with each other via the piece portion 7 (i.e., the input member 2 or the output member 3 and the engaging element 5 do not directly contact each other). This allows the generation of noise when the input member 2 or the output member 3 and the engaging element 5 contact each other to be further suppressed. On the other hand, when the thickness of the piece portion 7 in the first direction D1 is made thinner, the reverse input cutoff clutch 1 can be formed so that the input member 2 or the output member 3 is indirectly in contact with the engaging element 5 via the piece portion 7 only when the rotational torque from the input member 2 or the output member 3 is small, and the input member 2 or the output member 3 is in direct contact with the engaging element 5 when the rotational torque is large. This reduces the force transmission loss between the input member 2 or the output member 3 and the engaging element 5 while suppressing the generation of noise during contact more than in the prior art. Therefore, the versatility of the reverse input cutoff clutch 1 can be increased. Furthermore, the width dimensions W1, W2 of the engaging protrusions 57, 58 in the axial direction are smaller than the thickness dimension T1 of the engaging element 5 in the axial direction. This makes it possible to prevent the piece 7 housed in the recesses 55, 56 from protruding outward from the surface of the engaging element 5 facing the axial direction. Therefore, even if an elastic member 6 such as a leaf spring is provided between the output member 3 and the engaging element 5, interference between the piece 7 and the elastic member 6 can be prevented.

[0060] Second embodiment Next, a second embodiment of the present invention will be described. In the following description, the same components as those in the first embodiment described above will be denoted by the same reference numerals and will not be described as necessary. The specific components are not limited to these embodiments, and can be modified as appropriate without departing from the gist of the present invention. FIG. 5 is an explanatory diagram showing the positional relationship of the input member 2, the engaging member 5, and the piece portion 7 according to the second embodiment before contact. FIG. 6 is an explanatory diagram showing the positional relationship of the input member 2, the engaging member 5, and the piece portion 7 according to the second embodiment at low torque. FIG. 7 is an explanatory diagram showing the positional relationship of the input member 2, the engaging member 5, and the piece portion 7 according to the second embodiment at high torque. This embodiment differs from the first embodiment described above in that the contact relationship between the input member 2 or the output member 3 and the engaging member body 50 changes depending on the magnitude of the rotational torque input to the reverse input cutoff clutch 201.

[0061] In the second embodiment, the piece portion 7 is formed of an elastically deformable buffer material. In the second embodiment, the thickness and the like of the piece portion 7 are set so that the contact state between the input member 2 or the output member 3 and the engagement piece 5 changes as the piece portion 7 elastically deforms depending on the magnitude of the rotational force (rotational torque) input from the input member 2 or the output member 3.

[0062] Specifically, as shown in FIG. 5, before the arm 23 of the input member 2 comes into contact with the engaging element 5, a gap S is provided between the arm 23 and the engaging element 5, as in the first embodiment. In addition, an input-side piece 71 is provided at a portion of the engaging element 5 facing the input member 2. A protruding height H1 of the input-side piece 71 from the engaging element body 50 is smaller than the gap S between the arm 23 and the engaging element 5. As shown in FIG. 6, when a low torque rotational force that is less than a predetermined threshold is input from the input member 2, the arm 23 (input-side engaging portion 25) of the input member 2 comes into contact with the input-side piece 71, and the input member 2 does not come into direct contact with the engaging element body 50. Therefore, at the time of low torque, the rotational force input from the input member 2 is transmitted to the engaging element 5 via the input-side piece 71. 7, when a high torque rotational force equal to or greater than a predetermined threshold is input from the input member 2, the input-side piece portion 71 elastically deforms, causing direct contact between the arm portion 23 (input-side engagement portion 25) of the input member 2 and the engagement element main body 50. Thus, at the time of high torque, a portion of the rotational force input from the input member 2 is transmitted to the engagement element main body 50 via the input-side piece portion 71, and the remaining portion of the rotational force is transmitted directly to the engagement element main body 50.

[0063] Similarly, an output-side piece portion 72 is formed on the output member 3 so that the contact state between the output member 3 and the engagement piece 5 changes according to the magnitude of the rotational force (rotational torque). Specifically, Fig. 8 is an explanatory diagram showing the positional relationship between the output member 3, the engagement piece 5, and the piece 7 according to the second embodiment before they come into contact with each other. Fig. 9 is an explanatory diagram showing the positional relationship between the output member 3, the engagement piece 5, and the piece 7 according to the second embodiment at low torque. Fig. 10 is an explanatory diagram showing the positional relationship between the output member 3, the engagement piece 5, and the piece 7 according to the second embodiment at high torque.

[0064] As shown in FIG. 8, before the insertion portion 32 of the output member 3 comes into contact with the engaging element 5, a gap S is provided between the insertion portion 32 and the engaging element 5, as in the first embodiment. In addition, an output-side piece portion 72 is provided at a portion of the engaging element 5 facing the output member 3. A protruding height H2 of the output-side piece portion 72 from the engaging element body 50 is smaller than the gap S between the insertion portion 32 and the engaging element 5. As shown in FIG. 9, when the rotational force transmitted from the input member 2 to the output member 3 via the engaging element 5 is less than a predetermined threshold value (low torque), the output-side piece portion 72 attached to the engaging element body 50 comes into contact with the insertion portion 32 (output-side engaging portion 35) of the output member 3, and the engaging element body 50 does not come into direct contact with the output member 3. Therefore, at the time of low torque, the rotational force input from the input member 2 via the engaging element 5 is transmitted to the output member 3 via the output-side piece portion 72. 10, when the rotational force transmitted to the output member 3 is equal to or greater than a predetermined threshold (high torque), the pair of engagement members 5 move toward each other and the output-side piece portion 72 elastically deforms, so that the engagement members 5 and the output member 3 come into contact with each other in a substantially parallel manner. That is, the engagement member main body 50 and the insertion portion 32 (input-side engagement portion 25) of the output member 3 come into direct contact with each other. Therefore, when the torque is high, a portion of the rotational force input from the input member 2 to the engagement members 5 is transmitted to the engagement member main body 50 via the output-side piece portion 72, and the remaining portion of the rotational force is transmitted directly to the engagement member main body 50.

[0065] Also, the action when a reverse input acts on the output member 3 via an output mechanism (not shown) will be described. Fig. 11 is an explanatory diagram showing the positional relationship between the output member 3, the engaging piece 5, and the piece 7 before contact when a reverse input is applied in the second embodiment. Fig. 12 is an explanatory diagram showing the positional relationship between the output member 3, the engaging piece 5, and the piece 7 at low torque when a reverse input is applied in the second embodiment. Fig. 13 is an explanatory diagram showing the positional relationship between the output member 3, the engaging piece 5, and the piece 7 at high torque when a reverse input is applied in the second embodiment.

[0066] As shown in FIG. 11, in the state before the insertion portion 32 of the output member 3 comes into contact with the engagement member 5, the state is the same as when there is a forward input as described above, and therefore a description thereof will be omitted. As shown in FIG. 12, when a low-torque reverse input less than a predetermined threshold is input from the output member 3, the insertion portion 32 (output-side engagement portion 35) of the output member 3 comes into contact with the output-side piece portion 72 attached to the engagement member main body 50, and the output member 3 does not come into direct contact with the engagement member main body 50. Therefore, at the time of low torque, the rotational force input from the output member 3 is transmitted to the engagement member main body 50 via the output-side piece portion 72. On the other hand, as shown in FIG. 13, when a high-torque reverse input equal to or greater than a predetermined threshold is input from the output member 3, the output-side piece portion 72 is elastically deformed, so that the insertion portion 32 (input-side engagement portion 25) of the output member 3 comes into direct contact with the engagement member main body 50. Therefore, at the time of high torque, a part of the rotational force reversely input from the output member 3 is transmitted to the engaging element body 50 via the output-side piece portion 72, and the remaining part of the rotational force is directly transmitted to the engaging element body 50. Thereafter, as described above, the pair of engaging elements 5 move in directions away from each other, and the pair of pressing surfaces 51 frictionally engage with each other, thereby blocking the reverse input.

[0067] According to the reverse input cutoff clutch 1 of the second embodiment, when the rotational torque from the input member 2 or the output member 3 is less than a predetermined threshold, the input member 2 or the output member 3 and the engaging member 5 are indirectly in contact with each other via the piece portion 7. On the other hand, when the rotational torque is equal to or greater than the predetermined threshold, the input member 2 or the output member 3 and the engaging member 5 are in direct contact with each other. This reduces the force transmission loss between the input member 2 or the output member 3 and the engaging member 5 when the rotational torque is input to the input member 2 or the output member 3. Here, the torque is often low at the beginning of rotation. Therefore, since the input member 2 or the output member 3 and the piece portion 7 are in contact with each other at least at the beginning of rotation of the input member 2 or the output member 3, the generation of noise at the time of contact can be suppressed compared to the conventional technology in which the input member 2 or the output member 3 is in direct contact with the engaging member 5 from the beginning of rotation.

[0068] Third embodiment Next, a third embodiment of the present invention will be described. In the following description, the same components as those in the first embodiment described above will be denoted by the same reference numerals and will not be described. The specific components are not limited to these embodiments and can be modified as appropriate without departing from the gist of the present invention. FIG. 14 is a perspective view of a reverse input cutoff clutch 301 according to a third embodiment. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14. FIG. 16 is an enlarged view of XVI in FIG. 15. In this embodiment, the position at which the piece portion 7 is provided is different from that in the first embodiment described above.

[0069] In the third embodiment, the engagement element 5 has a first recess 381, a second recess 382, ​​a first engagement protrusion 391, a second engagement protrusion 392, a first link portion 373 and a second link portion 374 instead of the input side recess 55, the output side recess 56, the input side engagement protrusion 57, the output side engagement protrusion 58, the input side link portion 71 and the output side link portion 72 in the first embodiment. The first recess 381 is provided between the input side engaged portion 53 of the engaging element 5 and the bottom surface 52. The first recess 381 is provided so as to be recessed axially inward from an end face of the engaging element 5 on the output mechanism side in the axial direction (second axial side). Both ends of the first recess 381 in the first direction D1 are open towards the input side engaged portion 53 and the bottom surface 52 of the engaging element 5.

[0070] The second recess 382 is formed on the end face of the engaging member main body 50 opposite to the first recess 381. The second recess 382 is provided between the input side engaged portion 53 of the engaging member 5 and the bottom surface 52. The second recess 382 is provided so as to be recessed axially inward from the end face of the engaging member 5 on the axial input mechanism side (first axial side). Both ends of the first recess 381 in the first direction D1 are open towards the input side engaged portion 53 and the bottom surface 52 of the engaging member 5.

[0071] The first recess 381 and the second recess 382 thus formed are formed to have a depth such that their bottoms do not communicate with each other in the axial direction. In this embodiment, the shape of the first recess 381 and the shape of the second recess 382 are the same.

[0072] The first engagement protrusion 391 protrudes from the bottom of the first recess 381 toward the second side in the axial direction. The first engagement protrusion 391 is provided at approximately the center of the first recess 381 in the second direction D2. As shown in FIG. 14, the length dimension of the first engagement protrusion 391 along the first direction D1 is smaller than the length dimension between the input side engaged portion 53 and the bottom surface 52 of the engaging element 5. In other words, both ends of the first engagement protrusion 391 in the first direction D1 are located inside both ends of the first recess 381 in the first direction D1. As shown in FIG. 16, the first engagement protrusion 391 protrudes in the axial direction to a height equivalent to the end face of the engaging element main body 50.

[0073] The second engagement protrusion 392 protrudes from the bottom of the second recess 382 toward the first side in the axial direction. The second engagement protrusion 392 is provided at approximately the center of the second recess 382 in the second direction D2. As shown in FIG. 14, the length dimension of the second engagement protrusion 392 along the first direction D1 is smaller than the length dimension between the input side engaged portion 53 and the bottom surface 52 of the engagement element 5. In other words, both ends of the second engagement protrusion 392 in the first direction D1 are located inside both ends of the second recess 382 in the first direction D1. As shown in FIG. 16, the second engagement protrusion 392 protrudes in the axial direction to a height equivalent to the end face of the engagement element main body 50.

[0074] The first piece portion 373 is accommodated in the first recess 381 and engages with the first engagement protrusion 391. The first piece portion 373 is provided on a surface of the engagement element 5 facing the axial direction. The shape of the first piece portion 373 is the same as the shape of the piece portion 7 in the first embodiment. That is, the first piece portion 373 has a pair of main body portions 71a and a pair of connecting portions 71b that connect the pair of main body portions 71a to each other (see FIG. 4). The first piece portion 373 is accommodated in the first recess 381 by pushing the first piece portion 373 into the first recess 381 from the second axial side.

[0075] The second piece portion 374 is accommodated in the second recess 382 and engages with the second engagement protrusion 392. Thus, the second piece portion 374 is provided on a surface of the engagement element 5 facing the axial direction. The shape of the second piece portion 374 is the same as the shape of the first piece portion 373, and therefore a detailed description thereof will be omitted. The second piece portion 374 is accommodated in the second recess 382 by pushing the second piece portion 374 into the second recess 382 from the first side in the axial direction.

[0076] In the housed state of each piece 7, as shown in Fig. 16, one end of each piece 7 in the first direction D1 (upper side in Fig. 16) protrudes upward from the end face that defines the input-side engaged portion 53 of the engaging body 50. Similarly, the other end of each piece 7 in the first direction D1 (lower side in Fig. 16) protrudes downward from the end face that defines the bottom surface 52 of the engaging body 50. Therefore, when a rotational force acts on the input member 2 or the output member 3, the input member 2 and the output member 3 can come into contact with each piece 7 before the engaging body 50.

[0077] According to the reverse input cutoff clutch 301 of the third embodiment, the recesses 381, 382 are formed so as to be recessed from the engaging element 5 in the axial direction, and the piece portion 7 is provided along the surface of the engaging element 5 facing the axial direction. This makes it possible to suppress the enlargement of the radial dimension of the engaging element 5. In addition, the degree of freedom in the arrangement of the piece portion 7 can be increased, and the versatility of the reverse input cutoff clutch 301 can be improved. Furthermore, both the piece portion 7 and the engaging element 5 can be opposed to the input member 2 or the output member 3. Therefore, this is particularly suitable when it is desired to change the contact state between the input member 2 or the output member 3 and the engaging element 5 depending on the magnitude of the rotational torque. That is, when the rotational torque from the input member 2 or the output member 3 is small, the input member 2 or the output member 3 and the engaging element 5 can be indirectly contacted via the piece portion 7, and when the rotational torque is large, the input member 2 or the output member 3 and the engaging element 5 can be directly contacted.

[0078] (Modification of the third embodiment) Next, a modified example of the third embodiment of the present invention will be described. In the following description, the same components as those in the above-described third embodiment will be denoted by the same reference numerals and will not be described as necessary. Fig. 17 is a cross-sectional view of one of the engagement pieces 5 and the piece 7 according to a modified example of the third embodiment. Fig. 17 corresponds to Fig. 16 of the above-described third embodiment. In this modified example, the dimensions of the piece 7 relative to the recesses 381, 382 are different from those in the above-described third embodiment.

[0079] In the modified example of the third embodiment, each piece 7 is provided along a surface of the engaging piece 5 facing the axial direction, similarly to the third embodiment. In this modified example, one end (upper side in FIG. 16) of each piece portion 7 (first piece portion 473 and second piece portion 474) in the first direction D1 protrudes upward from the end face that defines the input-side engaged portion 53 of the engaging body 50. On the other hand, the other end (lower side in FIG. 16) of each piece portion 7 in the first direction D1 is located inside the end face that defines the bottom face 52 of the engaging body 50. Furthermore, the thickness dimension of each piece portion 7 along the axial direction is smaller than the depth dimension of each recess along the axial direction. Therefore, the outer end face of each piece portion 7 in the axial direction is located inside the end face of the engaging body 50 facing the axial direction.

[0080] According to the reverse input cutoff clutch 401 of the modified example of the third embodiment, the piece portion 7 does not protrude from the engaging element body 50, particularly in the portion corresponding to the output member 3. This makes it possible to suppress interference with the elastic member 6 provided between the output member 3 and the engaging element 5. Note that the piece portions 7 may be provided such that, for example, the other end (the lower side in FIG. 16) of each piece portion 7 in the first direction D1 protrudes downward from the end face that defines the bottom surface 52 of the engaging body 50. Even in this case, as long as the outer end face of each piece portion 7 in the axial direction is located more inward in the axial direction than the end face of the engaging body 50, interference with the elastic member 6 can be suppressed.

[0081] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the first embodiment described above, the piece portion 7 is provided at a position corresponding to both the input side engaged portion 53 and the output side engaged portion 54, but this is not limited thereto. The piece portion 7 only needs to be provided at a position corresponding to at least one of the input side engaged portion 53 and the output side engaged portion 54, and for example, the piece portion 7 may be provided only at a position corresponding to the input side engaged portion 53. However, the configuration of this embodiment in which the piece portion 7 is provided at a position corresponding to both the input side engaged portion 53 and the output side engaged portion 54 is advantageous in that it can suppress the generation of sound when the input member 2 and the output member 3 come into contact with the engagement element 5 and thereby obtain a more silent effect.

[0082] The shapes of the recesses 55, 56, 381, 382, ​​the engaging projections 57, 58, 391, 392 and the link portions 7 are not limited to the shapes described above. In the second and third embodiments, the recesses 381 and 382 may be formed so that the cross-sectional area perpendicular to the depth direction increases toward the bottom side in the depth direction, as in the first embodiment. Also, each recess 55, 56, 381, and 382 may be formed so that the cross-sectional area perpendicular to the depth direction is constant toward the bottom side in the depth direction. In this case, the circumferential length of the hole of each piece portion 7 may be made smaller than the circumferential length of each engagement protrusion 57, 58, 391, and 392, thereby performing an elastically deformed interference fit to hold the piece portion 7. Alternatively, the circumferential length of the outer shape of each piece portion 7 may be made larger than the circumferential length of the hole of each recess 55, 56, 381, and 382, ​​thereby performing an elastically deformed interference fit. Alternatively, the piece portion 7 may be held using an adhesive or the like.

[0083] In the third embodiment, the engagement element main body 50 may always be in contact with the input member 2 or the output member 3 via the piece 7 regardless of the magnitude of the rotational torque. Also, the third embodiment may be combined with the configuration of the second embodiment. That is, each piece 7 may be formed so that the contact relationship between the engagement element main body 50 and the input member 2 or the output member 3 changes depending on the magnitude of the rotational torque.

[0084] In each of the above-mentioned embodiments, the reverse input cutoff clutch 1 is a linkless type that does not use a link structure as a reverse input cutoff mechanism, but the present invention is not limited to this. A configuration having the above-mentioned piece portion 7 may be adopted in a link type reverse input cutoff clutch that uses a link mechanism, which is a known technology, as a reverse input cutoff mechanism.

[0085] The present disclosure may also be implemented in the following combinations: (1) a housing having a pressure-receiving surface on its inner circumferential surface; an input member having an input side engagement portion provided radially inward from the pressed surface and arranged coaxially with the axial direction of the pressed surface; an output member having an output side engaging portion disposed radially inward from the pressed surface and radially inward from the input side engaging portion, the output member being disposed coaxially with the pressed surface; a pair of engaging elements each having a pressing surface opposite to 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, the pair of engaging elements being movable relative to each other in a first direction along the radial direction; Equipped with the first direction corresponds to a direction in which the pair of engaging elements move toward and away from each other, When a rotational force is input to the input member, the pair of engagement elements move toward each other toward the inside in the first direction based on the engagement between the input side engagement portion and the input side engaged portion, and transmit the rotational force to the output member based on the engagement between the output side engagement portion and the output side engaged portion, When a rotational force is input in reverse to the output member, the pair of engagement pieces move away from each other toward the outside in the first direction based on the engagement between the output side engagement portion and the output side engaged portion, thereby frictionally engaging the pressed surface and the pressing surface, a piece portion formed of a separate member from the engaging element is provided at a position of the engaging element corresponding to at least one of the input side engaged portion and the output side engaged portion; Reverse input cut-off clutch. (2) The piece portion is formed of a cushioning material. The reverse input cut-off clutch described in (1). (3) the piece portion is provided with a surface treatment on a surface of a base material that is in contact with at least one of the input member and the output member; The reverse input cut-off clutch described in (1). (4) The pressure sensor further includes an elastic member that is elastically sandwiched between the output member and the engaging element and biases the engaging element outward in the first direction so that the engaging element approaches the pressed surface. A reverse input cut-off clutch according to any one of (1) to (3). (5) The engaging piece has a recess in which the piece is received, A cross-sectional area of ​​the recess perpendicular to the depth direction at a first position in the depth direction of the recess is larger than a cross-sectional area of ​​the recess perpendicular to the depth direction at a second position shallower than the first position. A reverse input cut-off clutch according to any one of (1) to (4). (6) The engaging piece has a recess in which the piece is received, The recess is provided with an engagement protrusion that engages with the piece portion. A reverse input cut-off clutch according to any one of (1) to (5). (7) The recess is recessed in the first direction from the engaging element, The engagement projection protrudes in the first direction from a bottom of the recess, A width dimension of the engaging projection along the axial direction is smaller than a thickness dimension of the engaging element along the axial direction. The reverse input cut-off clutch described in (6). (8) The recess is recessed from the engagement element in the axial direction, The engagement projection protrudes in the axial direction from a bottom of the recess, The piece portion is provided on a surface of the engagement piece facing the axial direction. The reverse input cut-off clutch described in (6). (9) a thickness dimension in the first direction of the piece portion is set so that when a rotational torque input to the reverse input cutoff clutch is less than a predetermined threshold value, at least one of the input member and the output member comes into contact with the piece portion, and when a rotational torque input to the reverse input cutoff clutch is equal to or greater than the predetermined threshold value, at least one of the input member and the output member comes into contact with the engaging element. A reverse input cut-off clutch according to any one of (1) to (8). [Explanation of symbols]

[0086] 1,201,301,401 Reverse input cutoff clutch 2 Input member 3 Output member 4. Housing 5 Engagement element 6 Elastic member 7. Piece 25 Input side engagement part 35 Output side engagement part 40 Pressed surface 51 Pressing surface 53 Input side engaged portion 54 Output side engaged part 55 Input side recess (recess) 56 Output side recess (recess) 57 Input side engagement protrusion (engagement protrusion) 58 Output side engagement protrusion (engagement protrusion) 381 First recess (recess) 382 Second recess (recess) 391 First engagement protrusion (engagement protrusion) 392 Second engagement protrusion (engagement protrusion) D1 First direction W1, W2 (width of the engaging protrusion along the axial direction) T1 (Axial direction) thickness of the engaging element

Claims

1. a housing having a pressure receiving surface on an inner circumferential surface; an input member having an input side engagement portion provided radially inward from the pressed surface and arranged coaxially with the axial direction of the pressed surface; an output member having an output side engaging portion disposed radially inward from the pressed surface and radially inward from the input side engaging portion, the output member being disposed coaxially with the pressed surface; a pair of engaging elements each having a pressing surface opposite to 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, the pair of engaging elements being movable relative to each other in a first direction along the radial direction; Equipped with the first direction corresponds to a direction in which the pair of engaging elements move toward and away from each other, When a rotational force is input to the input member, the pair of engagement elements move toward each other toward the inside in the first direction based on the engagement between the input side engagement portion and the input side engaged portion, and transmit the rotational force to the output member based on the engagement between the output side engagement portion and the output side engaged portion, When a rotational force is input in reverse to the output member, the pair of engagement pieces move away from each other toward the outside in the first direction based on the engagement between the output side engagement portion and the output side engaged portion, thereby frictionally engaging the pressed surface and the pressing surface, a piece portion formed of a separate member from the engaging element is provided at a position of the engaging element corresponding to at least one of the input side engaged portion and the output side engaged portion; Reverse input cut-off clutch.

2. The piece portion is formed of a cushioning material.

2. The reverse input cut-off clutch according to claim 1.

3. the piece portion is provided with a surface treatment on a surface of a base material that is in contact with at least one of the input member and the output member; 2. The reverse input cut-off clutch according to claim 1.

4. The pressure sensor further includes an elastic member that is elastically sandwiched between the output member and the engaging element and biases the engaging element outward in the first direction so that the engaging element approaches the pressed surface.

3. A reverse input cutoff clutch according to claim 1 or 2.

5. The engaging piece has a recess in which the piece is received, A cross-sectional area of ​​the recess perpendicular to the depth direction at a first position in the depth direction of the recess is larger than a cross-sectional area of ​​the recess perpendicular to the depth direction at a second position shallower than the first position.

3. A reverse input cutoff clutch according to claim 1 or 2.

6. The engaging piece has a recess in which the piece is received, The recess is provided with an engagement protrusion that engages with the piece portion.

3. A reverse input cutoff clutch according to claim 1 or 2.

7. The recess is recessed in the first direction from the engaging element, The engagement projection protrudes in the first direction from a bottom of the recess, A width dimension of the engaging projection along the axial direction is smaller than a thickness dimension of the engaging element along the axial direction.

7. The reverse input cutoff clutch according to claim 6.

8. The recess is recessed from the engagement element in the axial direction, The engagement projection protrudes in the axial direction from a bottom of the recess, The piece portion is provided on a surface of the engagement piece facing the axial direction.

7. The reverse input cutoff clutch according to claim 6.

9. a thickness dimension in the first direction of the piece portion is set so that when a rotational torque input to the reverse input cutoff clutch is less than a predetermined threshold value, at least one of the input member and the output member comes into contact with the piece portion, and when a rotational torque input to the reverse input cutoff clutch is equal to or greater than the predetermined threshold value, at least one of the input member and the output member comes into contact with the engaging element.

3. A reverse input cutoff clutch according to claim 1 or 2.

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