Reverse input cutoff clutch and assembly method thereof

Abstract

A reverse input cutoff clutch structure is provided that can restrict axial movement of an engagement element relative to an output member while reducing the number of parts. [Solution] The device includes a pressed member 2, an input member 3, an output member 4, an engaging element 5, and a retaining member 6. The retaining member 6 has a first spacer portion 38, a second spacer portion 39, and a connecting portion 40 that connects the first spacer portion 38 and the second spacer portion 39, and is attached to the output member 4 in a state in which the engaging element 5 is disposed between the first spacer portion 38 and the second spacer portion 39 in the axial direction of the pressed surface 7, thereby restricting axial movement of the engaging element 5 relative to the output member 4.

Description

[Technical field]

[0001] The present disclosure relates to a reverse input cut-off clutch which transmits rotational torque input to an input member to an output member, while completely cutting off rotational torque input inversely to the output member and not transmitting it to the input member, or which transmits only a portion of the torque to the input member and cuts off 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 reversely input to the output member and not transmitting it to the input member, or of 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 type and free type, depending on the difference in the mechanism for cutting off the rotational torque reversely input to the output member. A locking type reverse input cutoff clutch is equipped with a mechanism for preventing the output member from rotating when a 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 for causing the output member to rotate freely when a rotational torque is input to the output member. The choice of whether to use a locking type reverse input cutoff clutch or a free type reverse input cutoff clutch is appropriately determined 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 lock-type reverse input cutoff clutch. This conventional reverse input cutoff clutch 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 arranged radially inside the pressed surface, and is arranged coaxially with the pressed surface.

[0007] The output member has an output side engaging portion 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 this 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, so that the engaging element moves in a direction away from the pressed surface and the output side engaged portion engages 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 reversely input to the output member, the output side engaging portion engages with the output side engaged portion, so that the engaging element moves in a direction approaching the pressed surface, so that the pressing surface is pressed against the pressed surface and the pressing surface is frictionally engaged 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 tilted in the axial direction, the pressing surface and the pressed surface may locally come into contact with each other and bite into each other, which may increase the force required to switch from the locked state or semi-locked state to the unlocked state or semi-unlocked state, or may cause plastic deformation in the pressing surface and / or the pressed surface.

[0012] In this conventional reverse input cutoff clutch, two spacers that are independent of each other are provided on both axial sides of the engagement element, and the two spacers restrict axial movement of the engagement element relative to the input member and the output member.

[0013] However, using two spacers independent of each other increases the number of parts, which causes inconveniences such as increased parts management costs and increased assembly man-hours.

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

[0015] The reverse input disconnect clutch according to a first aspect of the present disclosure includes a pressed member, an input member, an output member, an engagement element, and a retaining member.

[0016] The pressed member has a pressed surface on its inner circumferential surface.

[0017] The input member has an input side engaging portion arranged radially inside the pressed surface, and is arranged coaxially with the pressed surface.

[0018] The output member has an output side engaging portion that is arranged radially inward of the input side engaging portion, and is arranged coaxially with the pressed surface.

[0019] 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 to be able to move in a first direction, which is the direction in which the pressing surface moves towards or away from the pressed surface.

[0020] The retaining member has a first spacer portion, a second spacer portion, and a connecting portion connecting the first spacer portion and the second spacer portion, and is attached to the output member with the engaging element positioned between the first spacer portion and the second spacer portion in the axial direction, thereby restricting axial movement of the engaging element relative to the output member.

[0021] When a rotational torque is input to the input member, the engaging element moves in a direction away from the pressed surface in the first direction 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 the pressing surface is pressed against the pressed surface, frictionally engaging the pressing surface with the pressed surface.

[0022] In a reverse input cutoff clutch according to a second aspect of the present disclosure, in the reverse input cutoff clutch of the first aspect of the present disclosure, the output member has an output shaft portion protruding from a center portion of an end surface on one axial side of the output side engagement portion toward the one axial side, and a small diameter shaft portion protruding from a center portion of an end surface on one axial side of the output side engagement portion toward the one axial side, the first spacer portion has a first through hole through which the output side engagement portion and / or the small diameter shaft portion is inserted, The second spacer portion has a second through hole through which the output side engagement portion is inserted.

[0023] In a reverse input cutoff clutch according to a third aspect of the present disclosure, in the reverse input cutoff clutch of the second aspect of the present disclosure, the retaining member has a locking protrusion protruding from an outer circumferential surface of the output side engaging portion or a surface facing an outer circumferential surface of the small diameter shaft portion, The output side engagement portion or the small diameter shaft portion has a locking groove in which the locking protrusion is engaged, at the same axial position on the outer circumferential surface as the locking protrusion.

[0024] In a reverse input blocking clutch of a fourth aspect of the present disclosure, in the reverse input blocking clutch of the third aspect of the present disclosure, the side surface on the other axial direction of the locking protrusion has an inclined surface portion, at least at the tip end portion in the protruding direction of the locking protrusion, which is inclined in a direction toward the one axial side as it approaches the tip end in the protruding direction.

[0025] In the reverse input cutting clutch of the fifth aspect of the present disclosure, in the reverse input cutting clutch of the fourth aspect of the present disclosure, the side surface on one axial direction of the locking protrusion is formed by a plane perpendicular to the axial direction of the pressed surface.

[0026] A reverse input cutoff clutch according to a sixth aspect of the present disclosure is a reverse input cutoff clutch according to any one of the third to fifth aspects of the present disclosure, wherein the locking protrusions are provided at a plurality of locations spaced apart in the circumferential direction.

[0027] A reverse input cutoff clutch according to a seventh aspect of the present disclosure is the reverse input cutoff clutch of any of the third to sixth aspects of the present disclosure, wherein the locking protrusion protrudes from an inner circumferential surface of the first through hole.

[0028] A reverse input cutoff clutch according to an eighth aspect of the present disclosure is the reverse input cutoff clutch of the seventh aspect of the present disclosure, wherein the first spacer portion has a discontinuous portion at least at one location in the circumferential direction.

[0029] In a reverse input cutoff clutch according to a ninth aspect of the present disclosure, in the reverse input cutoff clutch of the seventh aspect of the present disclosure, the outer circumferential surface of the small diameter shaft portion has a small diameter portion constituting one axial side portion, a large diameter portion constituting the other axial side portion, and a step surface facing one axial side and connecting the small diameter portion and the large diameter portion, an outer diameter of the small diameter portion is equal to or smaller than a diameter of an inscribed circle of the locking protrusion, The outer diameter of the large diameter portion is larger than the diameter of the inscribed circle of the locking protrusion, The locking groove is provided in the large diameter portion.

[0030] In the reverse input blocking clutch of the tenth aspect of the present disclosure, in the reverse input blocking clutch of the second aspect of the present disclosure, the input member has an input member side regulating portion that regulates the movement of the retaining member to one axial side relative to the output member based on engagement with the first spacer portion.

[0031] In a reverse input cutoff clutch according to an eleventh aspect of the present disclosure, in the reverse input cutoff clutch of the second aspect of the present disclosure, a retaining ring having a radially inner portion engaged with a portion of an outer peripheral surface of the small diameter shaft portion that is located on one axial side of the first spacer portion, The first spacer portion engages with a side surface on the other axial direction side of the radially outer portion of the retaining ring, thereby restricting movement of the retaining member toward the one axial direction side relative to the output member.

[0032] A reverse input disconnection clutch according to a twelfth aspect of the present disclosure is a reverse input disconnection clutch of any of the first to eleventh aspects of the present disclosure, which is provided with a biasing member that elastically biases the engagement element in a direction toward the pressed surface in relation to the first direction.

[0033] In a reverse input cutoff clutch according to one aspect of the present disclosure, in the reverse input cutoff clutch of a twelfth aspect of the present disclosure, The engaging element is composed of two engaging elements, The input side engagement portion is composed of two input side engagement portions, The biasing member is composed of two compression coil springs arranged between the two engaging elements, on either side of the retaining member in a second direction perpendicular to both the axial direction of the pressed surface and the first direction.

[0034] A reverse input cutoff clutch according to a thirteenth aspect of the present disclosure is the reverse input cutoff clutch of the twelfth aspect of the present disclosure, wherein the axial movement of the biasing member relative to the output member is restricted by the holding member.

[0035] In a reverse input blocking clutch of a 14th aspect of the present disclosure, in the reverse input blocking clutch of the 13th aspect of the present disclosure, the biasing member is arranged between the first spacer portion and the second spacer portion in the axial direction of the pressed surface, and is composed of a leaf spring elastically clamped between the output side engaging portion and the engaging element in the first direction.

[0036] A reverse input cutoff clutch according to a fifteenth aspect of the present disclosure is the reverse input cutoff clutch of the thirteenth aspect of the present disclosure, the connection portion of the holding member is arranged on both sides of the first spacer portion and the second spacer portion in a second direction perpendicular to both the axial direction of the pressed surface and the first direction, and is configured by two connection portions each having a holding hole extending in the first direction, The biasing member is composed of two compression coil springs that are fitted and held in the retaining holes of the two connection portions and elastically press both side portions in the second direction of the side of the engaging element opposite the pressed surface in the first direction.

[0037] A reverse input cutoff clutch according to a sixteenth aspect of the present disclosure is the reverse input cutoff clutch of the fifteenth aspect of the present disclosure, a pressing piece attached to an end of each of the two compression coil springs in the extension direction of the compression coil spring; The two compression coil springs elastically press the both side portions of the engagement element via the pressing piece.

[0038] In a reverse input cut-off clutch according to one embodiment of the present disclosure, in a reverse input cut-off clutch of a 16th embodiment of the present disclosure, the outer peripheral surface of the pressure piece is fitted within the inner peripheral surface of the retaining hole so as to be able to slide in the extension direction of the retaining hole.

[0039] In a reverse input blocking clutch according to one embodiment of the present disclosure, in a reverse input blocking clutch of either the fifteenth or sixteenth embodiment of the present disclosure, a guide surface portion is provided at the opening end of the inner surface of the retaining hole, the inner diameter of which increases toward the opening side.

[0040] In a reverse input disconnection clutch according to one embodiment of the present disclosure, in the reverse input disconnection clutch of the fifteenth or sixteenth embodiment of the present disclosure, the outer diameter of each of the two compression coil springs becomes smaller from the middle portion toward both sides in the extension direction of the compression coil spring.

[0041] A reverse input cutoff clutch according to a seventeenth aspect of the present disclosure is the reverse input cutoff clutch according to the fifteenth or sixteenth aspect of the present disclosure, The engaging element is composed of two engaging elements, The input side engagement portion is composed of two input side engagement portions, The retaining hole is formed by a through hole penetrating in the first direction, Each of the two compression coil springs is elastically compressed in the first direction between the two engagement elements.

[0042] In a reverse input cutting clutch according to an 18th aspect of the present disclosure, in the reverse input cutting clutch of the 17th aspect of the present disclosure, at least one of the two connection portions has a discontinuous portion at one location in the circumferential direction of the retaining hole.

[0043] A reverse input cutoff clutch according to a nineteenth aspect of the present disclosure is the reverse input cutoff clutch according to any one of the first to sixteenth aspects of the present disclosure, The engaging element is composed of two engaging elements, The input side engagement portion is made up of two input side engagement portions.

[0044] A method for assembling a reverse input cutoff clutch according to one aspect of the present disclosure is a method for assembling a reverse input cutoff clutch according to the seventeenth or nineteenth aspect of the present disclosure, the reverse input cutoff clutch including the biasing member, The method includes a step of combining the output member, the two engaging elements, the retaining member and the biasing member, and using an assembly jig that engages the input side engaged portions of the two engaging elements to displace the two engaging elements in a direction radially toward each other against the elastic biasing force of the biasing member, and then inserting the two engaging elements from the axial direction toward the radial inside of the pressed surface. Effect of the Invention

[0045] According to one aspect of the present disclosure, it is possible 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, and an assembly method thereof. [Brief description of the drawings]

[0046] [Figure 1] FIG. 1 is a cross-sectional view of a reverse input cutoff clutch according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is an exploded perspective view of the reverse input cutoff clutch of the first example. [Diagram 3] FIG. 3(a) is an enlarged view of part A in FIG. 1, and FIG. 3(b) is an enlarged view of part B in FIG. 3(a). [Figure 4] FIG. 4 is a cross-sectional view taken along line CC in FIG. 1, with some parts omitted. [Diagram 5] FIG. 5 is a cross-sectional view taken along line DD of FIG. 1, in which the holding member and the biasing member 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(a) is a perspective view of the holding member of the first example as viewed from one axial side, and FIG. 8(b) is a perspective view of the holding member as viewed from the other axial side. [Figure 9] 9(a) to 9(c) are cross-sectional views showing, in order of steps, a method of assembling an assembly that constitutes a part of the reverse input cutoff clutch of the first example. [Figure 10] 10(a) to 10(e) are cross-sectional views showing, in the order of steps, a method of assembling an assembly constituting a part of the reverse input cutoff clutch of a comparative example to the first example. [Figure 11] FIG. 11 is a view corresponding to the right side of FIG. 3(a) of a reverse input cutoff clutch according to a second example of an embodiment of the present disclosure. [Figure 12] 12(a) and 12(b) are views corresponding to FIGS. 8(a) and 8(b) and show a retaining member incorporated in a reverse input cutoff clutch according to a third embodiment of the present disclosure. [Figure 13] 13(a) and 13(b) are views corresponding to FIGS. 8(a) and 8(b) and show a retaining member incorporated in a reverse input cutoff clutch according to a fourth embodiment of the present disclosure. [Figure 14] 14(a) and 14(b) are views corresponding to FIGS. 8(a) and 8(b) and show a retaining member incorporated in a reverse input cutoff clutch according to a fifth example of an embodiment of the present disclosure. [Figure 15] FIG. 15(a) is a diagram corresponding to part A in FIG. 1 for a reverse input cut-off clutch according to a sixth example of an embodiment of the present disclosure, and FIG. 15(b) is an oblique view of a retaining member incorporated in the reverse input cut-off clutch, viewed from one axial side. [Figure 16] Figure 16(a) is a diagram corresponding to part A in Figure 1 for a reverse input cut-off clutch in a seventh example of an embodiment of the present disclosure, and Figure 16(b) is an oblique view of a retaining member incorporated in the reverse input cut-off clutch, viewed from one axial side. [Figure 17]FIG. 17(a) is a diagram corresponding to part A in FIG. 1 for a reverse input cut-off clutch according to an eighth example of an embodiment of the present disclosure, and FIG. 17(b) is an oblique view of a retaining member incorporated in the reverse input cut-off clutch, viewed from one axial side. [Figure 18] Figure 18(a) is an oblique view of a retaining member incorporated in a reverse input cut-off clutch of a ninth example of an embodiment of the present disclosure, viewed from one axial side, Figure 18(b) is a cross-sectional view of the retaining member, and Figure 18(c) is a view of the retaining member viewed from the right of Figure 18(b). [Figure 19] FIG. 19 is an exploded perspective view of a reverse input cutoff clutch according to a tenth example of an embodiment of the present disclosure. [Figure 20] FIG. 20 is a view corresponding to FIG. 4 and showing the reverse input cutoff clutch of the tenth example. [Figure 21] Figure 21(a) is a diagram of a reverse input cut-off clutch of a tenth example, corresponding to part A in Figure 1, and Figure 21(b) is an oblique view of a retaining member incorporated in the reverse input cut-off clutch, viewed from one axial side. [Figure 22] FIG. 22 is a cross-sectional view of a reverse input cutoff clutch according to an eleventh example of an embodiment of the present disclosure. [Figure 23] FIG. 23 is an exploded perspective view of the reverse input cutoff clutch of the eleventh example. [Figure 24] FIG. 24(a) is an enlarged view of a portion E in FIG. 22, and FIG. 24(b) is an enlarged view of a portion F in FIG. 24(a). [Diagram 25] FIG. 25 is a cross-sectional view taken along line GG of FIG. 22 with some parts omitted. [Figure 26] FIG. 26(a) is a perspective view of a retaining member of an eleventh example, as viewed from one axial side, and FIG. 26(b) is a perspective view of a first spacer portion constituting the retaining member, as viewed from the other axial side. [Figure 27] FIG. 27 is a view corresponding to the right side of the lower half of FIG. 3(a) of a reverse input cutoff clutch according to a twelfth example of an embodiment of the present disclosure. [Figure 28]FIG. 28 is a view corresponding to FIG. 26(a) and showing a holding member incorporated in a reverse input cutoff clutch according to a thirteenth example of an embodiment of the present disclosure. [Figure 29] FIG. 29 is a view corresponding to FIG. 26(a) and showing a holding member incorporated in a reverse input cutoff clutch according to a fourteenth example of an embodiment of the present disclosure. [Diagram 30] FIG. 30 is a view corresponding to FIG. 26(a) and showing a holding member incorporated in a reverse input cutoff clutch according to a fifteenth example of an embodiment of the present disclosure. [Diagram 31] FIG. 31 is a view corresponding to FIG. 26(a) and showing a holding member incorporated in a reverse input cutoff clutch according to a sixteenth example of an embodiment of the present disclosure. [Diagram 32] FIG. 32 is a view corresponding to FIG. 26(a) and showing a holding member incorporated in a reverse input cutoff clutch according to a seventeenth example of an embodiment of the present disclosure. [Diagram 33] Figure 33(a) is a diagram corresponding to part E in Figure 22 for a reverse input cut-off clutch of an 18th example of an embodiment of the present disclosure, and Figure 33(b) is a diagram corresponding to Figure 26(a) for a retaining member incorporated into the reverse input cut-off clutch. [Diagram 34] FIG. 34 is a view corresponding to part E in FIG. 22, of a reverse input cutoff clutch according to a nineteenth example of an embodiment of the present disclosure. [Diagram 35] Figure 35(a) is a diagram corresponding to part E in Figure 22 for a reverse input cut-off clutch in a twentieth example of an embodiment of the present disclosure, and Figure 35(b) is a diagram corresponding to Figure 26(a) for a retaining member incorporated into the reverse input cut-off clutch. [Diagram 36] FIG. 36(a) is a view corresponding to the HH cross section of FIG. 22 of a reverse input cutoff clutch according to a twenty-first example of an embodiment of the present disclosure, and FIG. 36(b) is an enlarged view of a portion I of FIG. 36(a). [Figure 37] FIG. 37 is a perspective view of a part of an output member and a retaining member in a reverse input cutoff clutch according to a twenty-first example of an embodiment of the present disclosure. [Figure 38]Figures 38(a) and 38(b) are cross-sectional views corresponding to portion J in Figure 25 for a reverse input cut-off clutch of a 22nd example of an embodiment of the present disclosure, and specifically, Figure 38(a) shows an unlocked state in which the engagement element has moved to the radially innermost position, and Figure 38(b) shows a locked or semi-locked state in which the engagement element has moved to the radially outermost position. [Figure 39] FIG. 39 is a cross-sectional view of a main portion for explaining a problem that can be prevented by the structure of the 22nd example. [Diagram 40] FIG. 40 is a cross-sectional view of a reverse input cutoff clutch according to a twenty-third example of an embodiment of the present disclosure, the cross-sectional view being equivalent to the portion J in FIG. 25 and partially omitted. [Diagram 41] FIG. 41 is a cross-sectional view of a reverse input cutoff clutch according to a twenty-fourth example of an embodiment of the present disclosure, the cross-sectional view being equivalent to a portion J in FIG. 25 and partially omitted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 10. FIG.

[0048] In the following description, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the reverse input cutoff clutch 1, more specifically, the axial direction, radial direction, and circumferential direction of the pressed surface 7 of the pressed member 2 that constitutes the reverse input cutoff clutch 1. In this example, the axial direction, radial direction, and circumferential direction of the reverse input cutoff 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).

[0049] <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, an engagement element 5, and a retaining member 6. The reverse input cutoff clutch 1 transmits the rotational torque input to the input member 3 to the output member 4, while having a reverse input cutoff function that completely blocks the rotational torque reversely input to the output member 4 and does not transmit it to the input member 3, or transmits only a portion of it to the input member 3 and cuts off the remainder.

[0050] The pressed member 2 has a pressed surface 7 on its inner circumferential surface. The input side engaging portion 14 of the input member 3 and the output side engaging portion 19 of the output member 4 are coaxially arranged radially inside the pressed surface 7, and the engaging element 5 is arranged so as to be movable toward and away from the pressed surface 7. The input side engaging portion 14, the output side engaging portion 19, and the engaging element 5 are rotatable radially inside the pressed surface 7. The pressed surface 7 forms a surface that comes into contact with the pressing surface 32 of the engaging element 5 when the engaging element 5 moves in a direction approaching the pressed surface 7.

[0051] In this example, the pressed surface 7 has a circular ring shape when viewed in the axial direction, and although not limited to this, in this example, it has a cylindrical surface shape whose inside diameter does not change in the axial direction.

[0052] In this example, the pressed member 2 is supported and fixed to a fixed portion of a housing or the like that does not rotate even when in use, and its rotation is restricted. Alternatively, the pressed member 2 is constituted by the fixed portion. The shape of the pressed member 2 is not limited as long as it has a pressed surface 7 on its inner circumferential surface.

[0053] In this example, the pressed member 2 includes an output element 8 and an input element (not shown). However, when implementing the present disclosure, a configuration in which the pressed member does not include an input element may also be adopted.

[0054] The output element 8 has an inner peripheral surface in the form of a stepped cylindrical surface. That is, the inner peripheral surface of the output element 8 is formed by connecting a large diameter cylindrical surface portion 9 on one axial side and a small diameter cylindrical surface portion 10 on the other axial side by a connection surface portion 11 facing one axial side. In this example, the large diameter cylindrical surface portion 9 forms the pressed surface 7. The output element 8 has an inward flange portion 12 that protrudes radially inward at the end portion on the other axial side of the small diameter cylindrical surface portion 10.

[0055] In this example, the input element 8 is fitted (spigot-fitted) into the output element 8 without any rattle, and in a state in which the output element 8 and the input element are positioned in the radial direction, the output element 8 and the input element are joined to each other 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 13 opening on a side surface of the output element 8 on the other axial side.

[0056] The input member 3 has an input-side engaging portion 14 arranged radially inside the pressed surface 7, and is arranged coaxially with the pressed surface 7. The input member 3 is connected to an input-side mechanism such as an electric motor, and is configured to be rotatable radially inside the pressed surface 7 by the input of rotational torque. The input-side engaging portion 14 is provided in a portion radially outwardly deviated from the rotation center O of the input member 3, and has a portion that engages with the input-side engaged portion 33 of the engager 5. The input-side engaging portion 14 is configured so that its radially inner surface 16 engages (contacts) with the radially inner surface 35 of the input-side engaged portion 33 as the input member 3 or the engager 5 rotates.

[0057] In this example, the input member 3 has an input shaft portion 15 in addition to the input side engagement portion 14.

[0058] The input shaft portion 15 has a substantially cylindrical shape.

[0059] The input side engaging portion 14 protrudes from a portion of the end face on the other axial side of the input shaft portion 15 that is radially outwardly spaced from the center of rotation O toward the other axial side.

[0060] There are no limitations on the shape of the input side engaging portion 14, so long as it is configured to engage with the input side engaged portion 33 of the engaging element 5. The number of input side engaging portions 14 is determined according to the number of engaging elements 5, and when the engaging element 5 is composed of a plurality of engaging elements 5, the input side engaging portion 14 is also composed of a plurality of input side engaging portions 14.

[0061] In the reverse input cutoff clutch 1 of this example, the engaging element 5 is configured by two engaging elements 5. Therefore, the input side engaging portion 14 is configured by two input side engaging portions 14 in accordance with the number of engaging elements 5. The two input side engaging portions 14 are disposed at two radially opposite positions on the radially outer side of the end face on the other axial side of the input shaft portion 15, and are spaced apart from each other in the radial direction of the input member 3. Each input side engaging portion 14 has a shape that is symmetrical in the circumferential direction.

[0062] In this example, the input side engagement part 14 has an end face shape of a substantially fan shape or a substantially trapezoid shape whose circumferential width increases toward the radially outer side when viewed from the axial direction. The radially inner side surface 16 of the input side engagement part 14 has a circumferential middle part formed of a flat surface perpendicular to the straight line connecting the rotation center O and the center of the input side engagement part 14 when viewed from the axial direction, and both circumferential side portions formed of a partially cylindrical convex surface inclined toward the radially outer side toward both circumferential sides. The radially outer side surface 17 of the input side engagement part 14 is formed of a partially cylindrical convex surface centered on the rotation center O. The two circumferential side surfaces 18 of the input side engagement part 14 are formed of flat surfaces inclined toward the radially outer side away from each other.

[0063] The input member 3 can be rotatably supported by the pressed member 2 or the fixed portion. In this example, the input shaft portion 15 of the input member 3 is rotatably supported inside the input side element by a radial bearing.

[0064] The output member 4 has an output-side engagement portion 19 arranged radially inward of the pressed surface 7 relative to the input-side engagement portion 14, and is arranged coaxially with the pressed surface 7. That is, the output member 4 is also arranged coaxially with the input member 3. 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.

[0065] The output side engaging portion 19 has a portion that can engage with the output side engaged portion 34 of the engaging element 5, and this portion is located radially inward of the input side engaging portion 14 and radially outward from the rotation center O of the output member 4. The output side engaging portion 19 is configured so that this portion engages with the output side engaged portion 34 as the output member 4 or the engaging element 5 rotates.

[0066] In this example, the output member 4 has, in addition to the output side engagement portion 19, an output shaft portion 20 and a small diameter shaft portion .

[0067] The output shaft portion 20 has a stepped cylindrical shape and is provided with an output flange portion 22 that protrudes radially outward from one axial end portion over the entire circumference.

[0068] The output side engagement portion 19 protrudes from the center of an end face 63 on one axial side of the output shaft portion 20 toward one axial side.

[0069] There are no limitations on the shape of the output side engaging portion 19, so long as it is configured to engage with the output side engaged portion 34. The number of portions of the output side engaging portion 19 that engage with the output side engaged portion 34 is determined according to the number of engaging elements 5, and when the engaging element 5 is configured with a plurality of engaging elements 5, the output side engaging portion 19 is also configured to have a plurality of the engaging portions. Note that even when the engaging element is configured with a single engaging element, the output side engaging portion can have a plurality of the engaging portions.

[0070] In this example, the output side engaging portion 19 is configured to have portions that engage with two output side engaged portions 34 in accordance with the number of the engaging elements 5 .

[0071] In this example, the output side engaging portion 19 has a substantially rectangular or oval end face shape when viewed in the axial direction, and protrudes from the center of the end face 63 on one axial side of the output shaft portion 20 toward one axial side. In other words, the distance from the rotation center O of the output member 4 to the outer circumferential surface of the output side engaging portion 19, which is the portion that engages with the output side engaged portion 34, is not constant in the circumferential direction. Therefore, the output side engaging portion 19 has a cam function.

[0072] More specifically, the outer peripheral surface of the output side engagement portion 19 is composed of two parallel flat surfaces 23 and two convex curved surfaces 24, each of which is a partial cylindrical surface. Therefore, the distance from the rotation center O of the output member 4 to the outer peripheral surface of the output side engagement portion 19 is not constant in the circumferential direction. Each of the two convex curved surfaces 24 is composed of a partial cylindrical surface centered on the rotation center O of the output member 4.

[0073] The output side engagement portion 19 is plane-symmetrical with respect to an imaginary plane that passes through the rotation center O of the output member 4 and is perpendicular to the flat surface 23. Furthermore, the output side engagement portion 19 is plane-symmetrical with respect to an imaginary plane that passes through the rotation center O of the output member 4 and is parallel to the flat surface 23.

[0074] The output side engaging portion 19 is disposed between the two input side engaging portions 14. In this example, the output member 4 is provided with a corner R portion 64 having a concave arc cross-sectional shape at the connection portion between an end face 63 on one axial side of the output shaft portion 20 and the outer circumferential surface of the output side engaged portion 34. This makes it possible to relieve stress acting on the connection portion between the end face 63 and the outer circumferential surface of the output side engaged portion 34.

[0075] The small diameter shaft portion 21 protrudes from the center of the end face on one axial side of the output side engagement portion 19 toward one axial side. In this example, the small diameter shaft portion 21 has a cylindrical shape. The small diameter shaft portion 21 has a locking groove 25 with which the locking protrusion 43 is engaged, at the same axial position on the outer circumferential surface as the locking protrusion 43 of the holding member 6 described later. In this example, the locking groove 25 is formed around the entire outer circumferential surface of the end portion on the other axial side of the small diameter shaft portion 21, and has a rectangular cross-sectional shape.

[0076] The output member 4 can be rotatably supported by the pressed member 2 or the fixed portion. In this example, the output member 4 is rotatably supported by a radial rolling bearing 26 on the radial inside of the output element 8 of the pressed member 2. The outer ring 27 of the radial rolling bearing 26 is fitted into the small diameter cylindrical surface portion 10 of the output element 8 without rattle, and is axially sandwiched between a side surface on one axial side of the inward flange portion 12 and a segmented annular retaining ring 28a engaged with an end portion on one axial side of the small diameter cylindrical surface portion 10. The inner ring 29 of the radial rolling bearing 26 is fitted outside the end portion on one axial side of the output shaft portion 20 without rattle, 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 28b engaged with an outer peripheral surface of an axial middle portion of the output shaft portion 20.

[0077] In the illustrated example, the radial rolling bearing 26 is configured as a ball bearing using balls as the rolling elements 30. However, the radial rolling bearing for supporting the output member 4 may also be configured as a tapered roller bearing using tapered rollers as the rolling elements or a roller bearing using cylindrical rollers.

[0078] One axial side portion of small diameter shaft portion 21 of output member 4 is supported by a sliding bearing (sleeve) 31 inside input shaft portion 15 of input member 3 so as to be freely rotatable relative to input member 3 .

[0079] The engaging element 5 has a pressing surface 32 facing the pressed surface 7, an input side engaged portion 33 engageable with the input side engaging portion 14, and an output side engaged portion 34 engageable with the output side engaging portion 19, 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 7.

[0080] When a rotational torque is input to the input member 3, the engaging element 5 moves in the first direction away from the pressed surface 7 based on the engagement of the input side engaging portion 14 with the input side engaged portion 33, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output side engaged portion 34 with the output side engaging portion 19. Conversely, when a rotational torque is input in the reverse direction to the output member 4, the output side engaging portion 19 engages with the output side engaged portion 34, pressing the pressing surface 32 against the pressed surface 7, frictionally engaging the pressing surface 32 with the pressed surface 7.

[0081] As long as the engaging element 5 has such a configuration, it may be constituted by one engaging element 5 or may be constituted by two or more engaging elements 5.

[0082] In this example, the engaging element 5 is composed of two engaging elements 5. Each engaging element 5 functions as an engaging element 5. Each 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 (the direction indicated by the arrow B in FIG. 5). The configuration of each engaging element 5 will be described below.

[0083] In this example, the radial direction with respect to the engaging element 5 is the direction in which the pressing surface 32 approaches or approaches the pressed surface 7, and corresponds to the direction indicated by the arrow A in Fig. 5. The width direction with respect to the engaging element 5 is the direction perpendicular to both the direction in which the pressing surface 32 approaches or approaches the pressed surface 7 and the axial direction of the pressed surface 7, and corresponds to the direction indicated by the arrow B in Fig. 5. In this example, the radial direction with respect to the engaging element 5 corresponds to the first direction, and the width direction with respect to the engaging element 5 corresponds to the second direction.

[0084] The pressing surface 32 is provided on the radially outer surface of the engaging element 5 facing the pressed surface 7. In this example, the pressing surface 32 is composed of two pressing surfaces 32 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 32 is composed of a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface 7.

[0085] Of the radially outer surface of the engagement element 5, a portion that is circumferentially offset from the two pressing surfaces 32 is located radially inward of a virtual circle that is centered on the rotation center O of the input member 3 and is tangent to the two pressing surfaces 32, when viewed from the axial direction. In other words, when the two pressing surfaces 32 are in contact with the pressed surface 7, the portion that is circumferentially offset from the two pressing surfaces 32 does not come into contact with the pressed surface 7.

[0086] It is preferable that the pressing surface 32 has a surface property that has a larger coefficient of friction with the pressed surface 7 than the other parts of the engaging element 5. The pressing surface 32 can be formed integrally with the other parts of the engaging element 5, or can be formed of the surface of a friction material fixed to the other parts of the engaging element 5 by adhesion or the like.

[0087] In this example, the input side engaged portion 33 is provided at a radially intermediate portion of the widthwise center portion of the engagement element 5. The shape of the input side engaged portion 33 is not limited as long as it is configured to be able to engage with the input side engaging portion 14.

[0088] In this example, the input side engaged portion 33 has a generally arched opening shape when viewed from the axial direction, and is configured as a through hole that axially passes through a radially intermediate portion at the widthwise center position of the engaging element 5 .

[0089] The input side engaged portion 33 has a size that allows the input side engaging portion 14 to be loosely inserted. Therefore, when the input side engaging portion 14 is inserted inside the input side engaged portion 33, there is a gap between the input side engaging portion 14 and the inner surface of the input side engaged portion 33 in the width direction and the radial direction of the engaging element 5. Therefore, the input side engaging portion 14 can be displaced in the rotation direction of the input member 3 relative to the input side engaged portion 33, and the input side engaged portion 33 can be displaced in the radial direction of the engaging element 5 relative to the input side engaged portion 14. In this example, of the inner surface of the input side engaged portion 33, a radially inner surface 35 facing radially outward is formed of a flat surface perpendicular to the first direction.

[0090] In this example, the output-side engaged portion 34 is provided at the center in the width direction of the radially inner surface of the engagement element 5. The shape of the output-side engaged portion 34 is not limited as long as it is configured to be able to engage with the output-side engaging portion 19.

[0091] In this example, the engaging element 5 has, on its radially inner surface, a flat surface portion 36 perpendicular to the radial direction of the engaging element 5, and the flat surface portion 36 has two protruding portions 37 protruding radially inward at two positions in the width direction of the engaging element 5. The output-side engaged portion 34 is formed by a portion of the flat surface portion 36 that is present between the two protruding portions 37 in the width direction. In this example, the width dimension of the output-side engaged portion 34, i.e., the distance between the two protruding portions 37, is greater than the width dimension of the flat surface 23 of the output-side engaging portion 19.

[0092] In the reverse input cutoff clutch 1 of this example, the pressing surfaces 32 of the two engaging elements 5 face radially opposite each other, and the flat surface portions 36 face each other, and each engaging element 5 is disposed radially inside the pressed member 2 so as to be movable in the first direction. In addition, the two input side engaging portions 14 of the input member 3 disposed on one axial side are axially inserted into the input side engaged portions 33 of the two engaging elements 5, and the output side engaging portion 19 of the output member 4 disposed on the other axial side is axially inserted between the output side engaged portions 34 of the two engaging elements 5. That is, the two engaging elements 5 are disposed so as to sandwich the output side engaging portions 19 from the radially outer side by the respective output side engaged portions 34.

[0093] When the two engaging elements 5 are positioned radially inside the pressed surface 7, the inner diameter dimension of the pressed surface 7 and the radial dimension of the engaging elements 5 are regulated so that a gap exists in at least one of the portions between the pressed surface 7 and the pressing surface 32 and between the tip faces of the convex portions 37.

[0094] The retaining member 6 has a first spacer portion 38, a second spacer portion 39, and a connection portion 40 connecting the first spacer portion 38 and the second spacer portion 39, and is attached to the output member 4 with the engaging element 5 positioned between the first spacer portion 38 and the second spacer portion in the axial direction of the pressed surface 7, thereby regulating axial movement of the engaging element 5 relative to the output member 4.

[0095] The shapes of the first spacer portion 38 and the second spacer portion 39 are not particularly limited as long as they are configured so that the engaging element 5 can be disposed between them in the axial direction of the pressed surface 7. When the engaging element 5 is configured with a plurality of engaging elements 5, the plurality of engaging elements 5 are disposed between the first spacer portion 38 and the second spacer portion 39 in the axial direction of the pressed surface 7. In this example, two engaging elements 5 are disposed between the first spacer portion 38 and the second spacer portion 39 in the axial direction of the pressed surface 7.

[0096] In this example, each of the first spacer portion 38 and the second spacer portion 39 is configured in a flat plate shape, and has a substantially oval or substantially rectangular end face shape when viewed in the axial direction.

[0097] In this example, the first spacer portion 38 has a first through hole 41 through which the small diameter shaft portion 21 is inserted. The first through hole 41 is configured as a circular hole that axially penetrates the center of the first spacer portion 38 and has an inner diameter slightly larger than the outer diameter of the small diameter shaft portion 21.

[0098] In this example, the first spacer portion 38 has an engagement recess 42 that opens only on the other axial side and into which the end portion on one axial side of the output-side engagement portion 19 can be inserted without rattle. The engagement recess 42 has a substantially oval or rectangular opening shape when viewed from the other axial side. The end portion on the other axial side of the first through hole 41 opens to the center of the bottom surface of the engagement recess 42.

[0099] The holding member 6 has a locking protrusion 43 protruding from a surface facing the outer circumferential surface of the output side engaging portion 19 or the outer circumferential surface of the small diameter shaft portion 21. The locking protrusion 43 can protrude from a surface facing the outer circumferential surface of the output side engaging portion 19 or the outer circumferential surface of the small diameter shaft portion 21, for example, of at least one of the first spacer portion 38, the second spacer portion 39, and the connecting portion 40. In this example, the locking protrusion 43 protrudes radially inward from the inner circumferential surface of the first through hole 41 of the first spacer portion 38. The locking protrusion 43 is a portion that is locked to the locking groove 25 of the output member 4. In this example, the locking protrusion 43 protrudes from the other axial side portion of the inner circumferential surface of the first through hole 41 radially inward over the entire circumference, except for a portion provided with a discontinuous portion 45.

[0100] In this example, the side surface on the other axial direction side of the locking protrusion 43 has an inclined surface portion 44 inclined in a direction toward one axial side as it approaches the radially inward side, which is the tip side in the protruding direction of the locking protrusion 43, at least in a radially inner portion, which is the tip side in the protruding direction of the locking protrusion 43. The inclined surface portion 44 functions as a guide surface when attaching the holding member 6 to the output member 4. When implementing the present disclosure, the entire side surface on the other axial direction side of the locking protrusion can also be configured with an inclined surface portion inclined in a direction toward one axial side as it approaches the radially inward. In this example, the side surface on one axial direction side of the locking protrusion 43 is configured with a plane perpendicular to the axial direction of the pressed surface 7.

[0101] In this example, the first spacer portion 38 has a discontinuous portion 45 at least at one location in the circumferential direction. The discontinuous portion 45 is a portion provided to facilitate elastic expansion and contraction of the inner diameters of the first through hole 41 and the locking protrusion 43, and opens to the inner peripheral surface of the first through hole 41, the outer peripheral surface of the first spacer portion 38, and the side surfaces on both axial sides. Therefore, the inner peripheral surface of the first through hole 41 and the locking protrusion 43 are discontinuous in the circumferential direction at the location where the discontinuous portion 45 exists. In this example, the discontinuous portion 45 is provided at one location in the circumferential direction of the first spacer portion 38, more specifically, at one location located on one short-side side (upper side in FIG. 4) of the center of the longitudinal direction (left-right direction in FIG. 4) of the first spacer portion 38.

[0102] In this example, the second spacer portion 39 has a second through hole 46 through which the output side engagement portion 19 is inserted. The second through hole 46 axially penetrates the center of the second spacer portion 39, has an opening shape that is approximately oval or approximately rectangular when viewed from the axial direction, and is large enough to allow the output side engagement portion 19 to be inserted without rattling. In this example, the second spacer portion 39 has a chamfered portion 65 at the opening edge portion on the other axial side of the second through hole 46. The chamfered portion 65 is configured as a C-chamfered portion having a linear cross-sectional shape. The chamfer depth of the chamfered portion 65 is set to a size that prevents interference between the chamfered portion 65 and the corner R portion 64 of the output member 4.

[0103] The connection portion 40 may be configured by one connection portion 40, or may be configured by two or more connection portions 40. In this example, the connection portion 40 is configured by two connection portions 40.

[0104] The shape of each of the connection parts 40 is not particularly limited as long as it is configured to connect the first spacer part 38 and the second spacer part 39 and not to hinder the movement of other components when the reverse input cutoff clutch 1 is used. In this example, each of the connection parts 40 has a rectangular column shape extending in the axial direction of the pressed surface 7. One end of each of the connection parts 40 on one axial side is integrally connected to a side surface on the other axial side of a central part in the short direction (first direction) of the end parts on both sides in the longitudinal direction (second direction) of the first spacer part 38, and the other end of each of the connection parts 40 on the other axial side is integrally connected to a side surface on one axial side of a central part in the short direction (first direction) of the end parts on both sides in the longitudinal direction (second direction) of the second spacer part 39. That is, in this example, the holding member 6 is configured as a single unit.

[0105] Furthermore, the holding member 6 is made of, but is not limited to, a synthetic resin.

[0106] The retaining member 6 is attached to the output member 4 in a state in which the other axial end of the output side engaging portion 19 is inserted without rattle into the second through hole 46 of the second spacer portion 39, the one axial end of the output side engaging portion 19 is inserted without rattle into the engaging recess 42 of the first spacer portion 38, the other axial end of the small diameter shaft portion 21 is inserted into the first through hole 41 of the first spacer portion 38, and the locking protrusion 43 of the first spacer portion 38 is engaged with the locking groove 25 of the small diameter shaft portion 21.

[0107] In this state, the widthwise intermediate portion of the radially inner portion of each engaging element 5 is positioned between the respective short end portions of the first spacer portion 38 and the second spacer portion in the axial direction of the pressed surface 7, and each connecting portion 40 is positioned between the output side engaged portions 34 of the two engaging elements 5.

[0108] 6, in the present example, as a rotational torque is input to the input member 3, in an unlocked state in which the output-side engaging portion 19 of the output member 4 is clamped from both radial (first) directions by the output-side engaged portions 34 of the two engaging elements 5, the radial (first) width dimension of each connecting portion 40 is restricted so that a gap exists between at least one of the radially opposite side surfaces of each connecting portion 40 and the output-side engaged portions 34 of the two engaging elements 5. More specifically, the radial (first) width dimension of each connecting portion 40 is smaller than the distance between the two flat surfaces 23 provided on the outer circumferential surface of the output-side engaging portion 19.

[0109] In this example, when the retaining member 6 is attached to the output member 4, movement of the retaining member 6 toward the other axial side relative to the output member 4 is regulated by the side surface on the other axial side of the second spacer portion 39 abutting against the end face 63 on one axial side of the output shaft portion 20, and / or by the bottom surface of the engagement recess 42 of the first spacer portion 38 abutting against the end face 66 on one axial side of the output side engagement portion 19.

[0110] That is, in this example, when the side surface of the second spacer portion 39 on the other axial direction abuts against the end face 63 to restrict the movement of the holding member 6 to the other axial direction relative to the output member 4, an axial gap is generated between the bottom surface of the engagement recess 42 and the end face 66 during the contact. When the bottom surface of the engagement recess 42 abuts against the end face 66 to restrict the movement of the holding member 6 to the other axial direction relative to the output member 4, an axial gap is generated between the side surface of the second spacer portion 39 on the other axial direction and the end face 63 during the contact. Alternatively, when the side surface of the second spacer portion 39 on the other axial direction abuts against the end face 63 and at the same time the bottom surface of the engagement recess 42 abuts against the end face 66, the movement of the holding member 6 to the other axial direction relative to the output member 4 is restricted.

[0111] In this example, movement of the retaining member 6 toward one axial side relative to the output member 4 is restricted by the side surface on one axial side of the locking protrusion 43 abutting against the side surface 67 of the inner surface of the locking groove 25 facing the other axial side.

[0112] The reverse input cutoff clutch 1 of this example further includes, as an optional component, a biasing member 47. The biasing member 47 elastically biases the engagement piece 5 in a direction approaching the pressed surface 7 in the first direction.

[0113] In this example, the biasing member 47 is disposed between the first spacer portion 38 and the second spacer portion 39 in the axial direction of the pressed surface 7, and is composed of a leaf spring elastically clamped between the output side engaging portion 19 and the engaging element 5 in the first direction, and axial movement relative to the output member 4 is restricted by the first spacer portion 38 and the second spacer portion 39.

[0114] In this example, the urging member 47 is configured by two urging members 47 arranged between the radially inner surfaces of the two engagement pieces 5 and the output side engagement portion 19, respectively.

[0115] The shape of the biasing member 47 is not particularly limited as long as it can elastically bias the engaging element 5 in a direction approaching the pressed surface 7 in the first direction. In this example, the biasing member 47 is configured by a leaf spring having two arms 48 and two connecting portions 49. Each arm 48 has a notch that opens at the tip, and has a substantially U-shaped planar shape when viewed from the plate thickness direction (first direction). Each connecting portion 49 has a band shape that connects both axial ends of the base ends of the two arms 48 and extends in the second direction.

[0116] In this example, the width dimension of the biasing member 47 in the axial direction of the pressed surface 7 is slightly smaller than the distance between the side surface on the other axial direction of the first spacer portion 38 that constitutes the retaining member 6 and the side surface on one axial direction of the second spacer portion 39.

[0117] The biasing member 47 is attached to the engaging member 5 in a state in which displacement in the axial direction and the second direction relative to the engaging member 5 is prevented by engaging the notches formed in the two arms 48 with the two protrusions 37 of the engaging member 5.

[0118] In this state, both axial side portions of the biasing member 47, more specifically, the portions of the two arms 48 located on both axial sides of the notch and the two connecting portions 49 are positioned in positions protruding on both axial sides relative to the engaging member 5.

[0119] Furthermore, an intermediate portion of the urging member 47 in the longitudinal direction (second direction) is disposed between the first spacer portion 38 and the second spacer portion 39 with respect to the axial direction of the pressed surface 7. This restricts the axial movement of the urging member 47 relative to the output member 4.

[0120] That is, in this example, the axial movement of the biasing members 47 attached to each engaging member 5 relative to the output member 4 is restricted by the first spacer portion 38 and the second spacer portion 39, thereby restricting the axial movement of the engaging members 5 relative to the output member 4.

[0121] In this example, the width dimension of the urging member 47 in the axial direction of the pressed surface 7 is slightly smaller than the distance between the side surface on the other axial direction side of the first spacer portion 38 and the side surface on one axial direction side of the second spacer portion 39 that constitute the holding member 6. Therefore, the engagement piece 5 is restricted from moving in the axial direction of the pressed surface 7 by the holding member 6 while being allowed to move in the first direction relative to the pressed surface 7.

[0122] In this example, regardless of the positional relationship between the engaging element 5 and the output side engaging portion 19, more specifically, regardless of the radial position of the engaging element 5 and the rotational phase of the output side engaging portion 19 relative to the engaging element 5, the output side engaging portion 19 is made to elastically abut against two connecting portions 49 constituting the biasing member 47. This suppresses rattling between the output side engaging portion 19 and the output side engaged portion 34.

[0123] <Operation explanation of reverse input cutoff clutch> The operation of the reverse input cutoff clutch 1 of this embodiment will be described with reference to Figures 6 and 7. In Figures 6 and 7, the holding member 6 and the biasing member 47 are omitted, and the radial gaps between the input member 3 and the output member 4 and the two engagement elements 5 are exaggerated.

[0124] In the reverse input cutoff clutch 1 of this example, when a rotational torque is input to the input member 3, the engagement element 5 moves in a direction away from the pressed surface 7, regardless of the rotational direction of the input member 3. Then, the rotational torque input to the input member 3 is transmitted to the output member 4 via the engagement element 5.

[0125] That is, when a rotational torque is input to the input member 3, the input side engaging portion 14 rotates in the rotation direction of the input member 3 (counterclockwise in the example of FIG. 6) inside the input side engaged portion 33, as shown in FIG. 6. This reduces the gap between the radial inner surface 16 of the input side engaging portion 14 and the radial inner surface 35 of the input side engaged portion 33, and brings the radial inner surface 16 of the input side engaging portion 14 into contact with the radial inner surface 35 of the input side engaged portion 33.

[0126] When the input member 3 rotates further from this state, the radial inner surface 16 of the input side engaging portion 14 presses the radial inner surface 35 of the input side engaged portion 33 radially inward, and the engaging element 5 moves in a direction away from the pressed surface 7 against the elastic biasing force of the biasing member 47. That is, the engaging element 5 moves radially inward based on the engagement with the input member 3, and the output side engaged portion 34 of the engaging element 5 engages with the output side engaging portion 19 of the output member 4. In this example, the two engaging elements 5 move in a direction approaching each other, the radial inner surfaces of the two engaging elements 5 approach each other, and the output side engaging portion 19 of the output member 4 is sandwiched by the output side engaged portions 34 of the two engaging elements 5 from both radial sides.

[0127] More specifically, when the output-side engaged portion 34 of the engager 5 engages with the output-side engaging portion 19, the output member 4 rotates so that the flat surface 23 of the output-side engaging portion 19 becomes parallel to the output-side engaged portion 34 of the engager 5, bringing the flat surface 23 into contact with the output-side engaged portion 34 without any rattling. As a result, the rotational torque input to the input member 3 is transmitted to the output member 4 via the engager 5, and is output from the output member 4.

[0128] When a rotational torque is reversely input to the output member 4, the engaging element 5 moves in a direction approaching the pressed surface 7, regardless of the rotational direction of the output member 4. Then, the rotational torque reversely input to the output member 4 is completely blocked and not transmitted to the input member 3, or only a portion of the rotational torque reversely input to the output member 4 is transmitted to the input member 3 and the remainder is blocked.

[0129] More specifically, as shown in Fig. 7, the output-side engaging portion 19 rotates in the rotation direction of the output member 4 (clockwise in the example of Fig. 7) between the output-side engaged portion 34 of the engaging element 5. The output-side engaged portion 34 is pressed radially outward by a connection portion (corner portion) between the flat surface 23 and the convex curved surface 24 of the outer circumferential surface of the output-side engaging portion 19, and the engaging element 5 moves in a direction approaching the pressed surface 7.

[0130] That is, based on engagement with the output member 4, the engaging element 5 moves radially outward (the two engaging elements 5 move in the direction away from each other), and the pressing surface 32 of the engaging element 5 comes into contact with the pressed surface 7 and frictionally engages with the pressed surface 7.

[0131] As a result, the rotational torque inputted inversely 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 inversely to the output member 4 is transmitted to the input member 3 and the remainder is blocked.

[0132] In order 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 engagement member 5 is clamped between the output side engagement portion 19 and the pressed member 2 so that the pressing surface 32 of the engagement member 5 does not slide against the pressed surface 7, thereby locking the output member 4.

[0133] In order to transmit only a portion of the rotational torque inputted in reverse 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 19 and the pressed member 2 so that the pressing surface 32 of the engaging element 5 slides against the pressed surface 7, thereby semi-locking the output member 4.

[0134] In the reverse input cutoff clutch 1 of this embodiment, the size of the gap between each component is adjusted so that the above operation is possible. In particular, in a positional relationship in which the pressing surface 32 of the engaging element 5 contacts the pressed surface 7, a gap is set to exist between the radially inner surface 16 of the input side engaging portion 14 and the radially inner surface 35 of the input side engaged portion 33.

[0135] This prevents the input side engagement portion 14 from blocking the radially outward movement of the engagement element 5 when a rotational torque is input in reverse to the output member 4, and even after the pressing surface 32 comes into contact with the pressed surface 7, the surface pressure acting on the contact portion between the pressing surface 32 and the pressed surface 7 changes depending on the magnitude of the rotational torque input in reverse to the output member 4, thereby ensuring that the output member 4 is properly locked or semi-locked.

[0136] In the reverse input cutoff clutch 1 of this example, the biasing member 47 elastically biases the engagement element 5 in a direction approaching the pressed surface 7 in the first direction. This allows the two pressing surfaces 32 of the engagement element 5 to be kept in contact with the pressed surface 7 except when a rotational torque is input to the input member 3. Therefore, when a rotational torque is reversely input to the output member 4, the surface pressure at the contact portion between the two pressing surfaces 32 of the engagement element 5 and the pressed surface 7 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.

[0137] In the reverse input cutoff clutch 1 of this embodiment, one holding member 6 is used as a restricting member for restricting the engagement element 5 from moving in the axial direction of the pressed surface 7. Therefore, the number of parts can be reduced compared to a case where two independent spacers installed on both axial sides of the engagement element 5 are used as such restricting members. Therefore, the management costs of parts can be reduced, and the number of steps for assembling the reverse input cutoff clutch 1 can be reduced.

[0138] In the reverse input cutoff clutch 1 of this example, the retaining member 6 is prevented from coming off in one axial direction from the output member 4 by engaging the locking protrusion 43 provided on the retaining member 6 with the locking groove 25 provided on the output member 4. This makes the retaining ring unnecessary compared to a structure in which a segmented annular retaining ring is engaged with a locking groove provided in a portion of the output member adjacent to one axial side of the portion on which the retaining member is fitted, and the retaining ring is used to prevent the retaining member from coming off in one axial direction from the output member. Therefore, from this point of view as well, the number of parts can be reduced.

[0139] <How to assemble the reverse input cutoff clutch> The assembly method of the reverse input cut-off clutch of this example includes the steps of combining the output member 4, two engaging members 5, a retaining member 6, and two biasing members 47, and using an assembly jig (not shown) that engages the input side engaged portions 33 of the two engaging members 5, displacing the two engaging members 5 radially toward each other against the elastic biasing forces of the respective biasing members 47, and then inserting the two engaging members 5 axially into the radially inner side of the pressed surface 7.

[0140] More specifically, the reverse input cutoff clutch 1 of this embodiment can be assembled, for example, as follows.

[0141] 9(a), the inner ring 29 of the radial rolling bearing 26 is fitted onto the output shaft portion 20 of the output member 4 without any rattle, and the retaining ring 28b is engaged with the outer circumferential surface of the axially intermediate portion of the output shaft portion 20. The biasing members 47 are respectively assembled to the radially inner ends of the two engaging elements 5.

[0142] 9(a) and 9(b), the two engaging elements 5 are arranged so as to sandwich the two connecting portions 40 constituting the holding member 6 from the radially outer side by the respective biasing members 47. Then, this arranged state is maintained by engaging the input side engaged portions 33 of the two engaging elements 5 with the assembly jig.

[0143] 9(b) to 9(c), the output-side engaging portion 19 and the small diameter shaft portion 21 of the output member 4 are inserted from the other axial side into the first through-hole 41 of the first spacer portion 38 and the second through-hole 46 of the second spacer portion 39 that constitute the holding member 6, and the locking protrusion 43 of the holding member 6 is locked into the locking groove 25 of the output member 4. In this way, the two engaging elements 5, the two biasing members 47, and the holding member 6 are combined to obtain a preliminary assembly 50 as shown in FIG. 9(c).

[0144] In this example, when the output-side engaging portion 19 and the small diameter shaft portion 21 of the output member 4 are inserted from the other axial side into the first through-hole 41 of the first spacer portion 38 and the second through-hole 46 of the second spacer portion 39 constituting the holding member 6, the locking protrusion 43 elastically expands in diameter and rides up from the end portion on one axial side of the small diameter shaft portion 21 onto the outer circumferential surface of the small diameter shaft portion 21. Thereafter, the locking protrusion 43 moves to the same axial position as the locking groove 25, and then contracts in diameter by elastic restoration to be locked in the locking groove 25.

[0145] In this example, an inclined surface portion 44 that is inclined in a direction toward one axial side as it goes radially inward is provided on the radially inner portion of the side surface of the other axial side of the locking protrusion 43. Therefore, when the locking protrusion 43 rides up from the end portion on one axial side of the small diameter shaft portion 21 onto the outer circumferential surface of the small diameter shaft portion 21, the inclined surface portion 44 serves as a guide surface, making it easier for the locking protrusion 43 to elastically expand in diameter. In other words, the locking protrusion 43 easily rides up from the end portion on one axial side of the small diameter shaft portion 21 onto the outer circumferential surface of the small diameter shaft portion 21.

[0146] In this example, the first spacer portion 38 has a discontinuous portion 45 at one location in the circumferential direction, and the elastic expansion / contraction rigidity of the first through hole 41 and the locking protrusion 43 is reduced based on the presence of the discontinuous portion 45. Therefore, also from this aspect, when the locking protrusion 43 rides up onto the outer circumferential surface of the small diameter shaft portion 21 from one axial end of the small diameter shaft portion 21, the locking protrusion 43 tends to elastically expand in diameter.

[0147] In this example, the side surface on one axial direction side of the locking protrusion 43 is formed by a plane perpendicular to the axial direction of the pressed surface 7. For this reason, even if a force toward one axial direction side acts on the holding member 6 with respect to the output member 4 while the locking protrusion 43 is locked in the locking groove 25, the engagement between the side surface on one axial direction side of the locking protrusion 43 and the side surface on one axial direction side constituting a part of the inner surface of the locking groove 25 effectively prevents the locking protrusion 43 from slipping out radially outward from the locking groove 25.

[0148] 9(c) is obtained, the output member 4 is then inserted into the inside of the output element 8 from one axial side. When inserting the output member 4 into the inside of the output element 8, the two engaging elements 5 are displaced radially toward each other against the elastic biasing forces of the biasing members 47 by the assembly jig engaged with the input-side engaged portions 33 of the two engaging elements 5. This facilitates the assembly work.

[0149] After the end face on the other axial side of the outer ring 27 of the radial rolling bearing 26 abuts against the side face on one axial side of the inward flange portion 12, the assembly jig is withdrawn, and the two engaging elements 5 are displaced radially away from each other by the elastic biasing forces of the respective biasing members 47, so that the respective pressing surfaces 32 abut against the pressed surface 7. Then, a retaining ring 28a is engaged with the end portion on one axial side of the small diameter cylindrical surface portion 10.

[0150] Next, the sliding bearing 31 is fitted onto one axial side portion of the small diameter shaft portion 21 of the output member 4 to obtain the output side assembly 51. The order of steps for assembling the output side assembly 51 can be changed as appropriate as long as no contradiction occurs.

[0151] Moreover, an input member 3 is rotatably supported inside the input element by the radial bearing, thereby obtaining an input side assembly.

[0152] Next, with the circumferential phases of the two input side engaging portions 14 of the input member 3 and the input side engaged portions 33 of the two engaging elements 5 aligned, the output side assembly 51 and the input side assembly are displaced in the axial direction toward each other.

[0153] As a result, the input element is fitted into the output element 8 without any rattle, the two input engaging portions 14 of the input member 3 are inserted into the input engaged portions 33 of the two engagers 5, and the sliding bearing 31 is fitted inside the input shaft portion 15 of the input member 3. The output element 8 and the input element are then joined to each other with joining members such as bolts, thereby assembling the reverse input cutoff clutch 1.

[0154] Here, a comparative example to this example will be described with reference to Figures 10(a) to 10(e). The comparative example differs from this example in that a first spacer 52 and a second spacer 53, which are independent of each other, and a retaining ring 54 are used instead of the retaining member 6 of this example in order to restrict the axial movement of the two engaging elements 5.

[0155] Regarding the structure of the comparative example, when assembling the preliminary assembly 50a shown in Fig. 10(e), as shown in Fig. 10(a) and Fig. 10(b), the other axial end of the output-side engaging portion 19 is inserted into the through-hole 55 of the first spacer 52. In addition, the biasing member 47 is assembled to the radially inner end of each engaging element 5.

[0156] Next, as shown in Figures 10(b) and 10(c), the two engagement pieces 5 are arranged so that the axial middle portion of the output side engagement portion 19 is sandwiched from the radial outside by the biasing members 47 attached to each of the engagement pieces 5.

[0157] Next, as shown in FIGS. 10( c ) and 10 ( d ), one axial end of the output side engaging portion 19 is inserted into the through hole 55 of the second spacer 53 .

[0158] Next, as shown in Figs. 10(d) to 10(e), the retaining ring 54 is engaged with the engaging groove 25 of the output member 4 to obtain a preliminary assembly 50a.

[0159] As described above, when assembling the preliminary assembly 50a of the comparative example, three steps must be performed to assemble the components for restricting the axial movement of the two engaging elements 5 to the output member 4: a step of assembling the first spacer 52, a step of assembling the second spacer 53, and a step of assembling the retaining ring 54.

[0160] In contrast, when assembling the preliminary assembly 50 of this example (see FIG. 9(c)), it is necessary to perform only the process of assembling the retaining member 6 as a process of assembling a member for restricting the axial movement of the two engaging members 5 to the output member 4. Therefore, according to the reverse input cutoff clutch 1 of this example, the number of assembly steps can be reduced compared to the reverse input cutoff clutch of the comparative example, thereby improving the ease of assembly.

[0161] When implementing the present disclosure, the materials of the pressed member, input member, output member, and engaging element are not particularly limited. For example, metals such as iron alloys, copper alloys, and aluminum alloys, as well as synthetic resins mixed with reinforcing fibers as necessary, can be used as these materials. The pressed member, input member, output member, and engaging element can be made of the same material or different materials. The material of the holding member can also be made of a material different from that of this example, such as metals such as iron alloys, copper alloys, and aluminum alloys.

[0162] In implementing the present disclosure, as long as the condition that the output member is locked or semi-locked when a rotational torque is input in reverse to the output member is satisfied, a lubricant can be applied to the portions where the pressed member, the input member, the output member, and the engaging member come into contact with each other. Alternatively, at least one of the pressed member, the input member, the output member, and the engaging member can be made of oil-retaining metal.

[0163] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to Fig. 11. In this example, the shape of the small diameter shaft portion 21a of the output member 4a is different from that of the first example.

[0164] In this example, the outer circumferential surface of small diameter shaft portion 21a has small diameter portion 56 constituting one axial side portion, large diameter portion 57 constituting the other axial side portion, and step surface 58 facing one axial side and connecting small diameter portion 56 and large diameter portion 57. The outer diameter of small diameter portion 56 is equal to or smaller than the diameter of the inscribed circle of locking protrusion 43 of holding member 6, and the outer diameter of large diameter portion 57 is larger than the diameter of the inscribed circle of locking protrusion 43. Locking groove 25 is provided in large diameter portion 57.

[0165] More specifically, in this example, the small diameter portion 56 is provided on the outer peripheral surface of the small diameter shaft portion 21a from the end portion on one axial side to the middle portion on the axial side, and is made of a cylindrical surface whose outer diameter does not change in the axial direction except for the chamfered portion on the edge portion on one axial side. In this example, the large diameter portion 57 is provided on the outer peripheral surface of the small diameter shaft portion 21a at the end portion on the other axial side, and is made of a cylindrical surface whose outer diameter does not change in the axial direction except for the portion where the locking groove 25 is present. In this example, the step surface 58 is made of a conical surface that is inclined in the direction toward the other axial side as it goes radially outward. In this example, the locking groove 25 is provided on the end portion on the other axial side of the large diameter portion 57.

[0166] In this example, of the small diameter shaft portion 21a, one axial side portion having a small diameter portion 56 on its outer peripheral surface is supported by a sliding bearing 31 on the inside of the input shaft portion 15 of the input member 3 so as to be freely rotatable relative to the input member 3.

[0167] In this example, the outer diameter of a small diameter portion 56 constituting one axial side portion of the outer circumferential surface of the small diameter shaft portion 21a is equal to or smaller than the diameter of the inscribed circle of the locking protrusion 43, and the outer diameter of a large diameter portion 57 constituting the other axial side portion of the outer circumferential surface of the small diameter shaft portion 21a is larger than the diameter of the inscribed circle of the locking protrusion 43, and the locking groove 25 is provided in the large diameter portion 57. For this reason, in the assembly work of the reverse input cutoff clutch of this example, when the small diameter shaft portion 21a is inserted from the other axial side into the first through hole 41 of the first spacer portion 38 constituting the holding member 6 and the locking protrusion 43 is locked in the locking groove 25, the locking protrusion 43 only needs to pass through in the axial direction only the portion of the large diameter portion 57 located on one axial side of the locking groove 25 while elastically expanding in diameter.

[0168] Therefore, during assembly, the distance over which locking protrusion 43 is moved axially while being elastically expanded in diameter can be shortened. This improves the ease of assembly and effectively prevents damage to locking protrusion 43. The configurations and effects of the other parts of the second example are the same as those of the first example.

[0169] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to Figures 12(a) and 12(b). In this example, the shape of a first spacer portion 38a constituting a holding member 6a is different from that of the first example.

[0170] In this example, the first spacer portion 38a has two discontinuous portions 45 in the circumferential direction. More specifically, the discontinuous portions 45 are provided at two locations located on both sides in the short direction of the longitudinal center of the first spacer portion 38a.

[0171] In this example, by adopting such a configuration, the expansion / contraction rigidity of the first through hole 41 and the locking protrusion 43 is further reduced. This makes it easier to move the outer circumferential surface of the small diameter shaft portion 21 in the axial direction while elastically expanding the diameter of the locking protrusion 43 when assembling the holding member 6a to the output member. This improves the ease of assembly of the reverse input cutoff clutch. The configuration and effects of the other parts of the third example are the same as those of the first example.

[0172] [Example 4] A fourth example of the embodiment of the present disclosure will be described with reference to Figures 13(a) and 13(b). In this example, the shape of a first spacer portion 38b constituting a holding member 6b is different from that of the first example.

[0173] In this example, the first spacer portion 38b does not have any discontinuous portion at any point in the circumferential direction and is continuous around the entire circumference. Instead, in this example, the locking protrusions 43a are provided at a plurality of points spaced apart in the circumferential direction on the inner circumferential surface of the first through hole 41 in the first spacer portion 38b. That is, in this example, the circumferential length of each locking protrusion 43a is set short, so that each locking protrusion 43a is easily elastically deformed in the radial direction. In this example, an inclined surface portion 44 that functions as a guide surface during assembly is provided on the radially inner portion of the side surface on the other axial side of each locking protrusion 43a.

[0174] In this example, since each of the locking protrusions 43a is easily elastically deformed in the radial direction, when assembling the holding member 6b to the output member, the locking protrusions 43a are easily moved in the axial direction on the outer circumferential surface of the small diameter shaft portion 21 while elastically expanding the diameter of the inscribed circle. Therefore, the assembly workability of the reverse input cutoff clutch can be improved. The configuration and the effects of the other parts of the fourth example are the same as those of the first example.

[0175] [Example 5] A fifth example of the embodiment of the present disclosure will be described with reference to Figures 14(a) and 14(b). In this example, the shape of a first spacer portion 38c constituting a holding member 6c is different from that of the first example.

[0176] In this example, the first spacer portion 38c has the shape features of both the third and fourth examples. That is, the first spacer portion 38c has discontinuous portions 45 at two circumferential locations, that is, at both short-side positions of the longitudinal center of the first spacer portion 38c, and has locking protrusions 43a at multiple circumferentially separated positions on the inner circumferential surface of the first through-hole 41.

[0177] In this example, by adopting such a configuration, it is made easier to perform the work of moving the outer circumferential surface of the small diameter shaft portion 21 in the axial direction while elastically expanding the diameter of the inscribed circle of the multiple locking protrusions 43, thereby further improving the ease of assembly of the reverse input cutoff clutch. The configuration and effects of the other parts of the fifth example are the same as those of the first example.

[0178] [Example 6] A sixth example of the embodiment of the present disclosure will be described with reference to Figures 15(a) and 15(b). In this example, the structure for restricting the axial position of the holding member 6d relative to the output member 4b is different from that of the first example.

[0179] In this example, in the holding member 6d, the first spacer portion 38d has a first through hole 41a through which the output side engagement portion 19 is inserted. The first through hole 41a axially penetrates the center of the first spacer portion 38d, has a substantially oval or rectangular opening shape when viewed from the axial direction, and is sized to allow the output side engagement portion 19 to be inserted without rattling.

[0180] In this example, with the holding member 6d assembled to the output member 4b, one axial end of the output side engaging portion 19 and the other axial end of the small diameter shaft portion 21b are inserted into the first through hole 41a. In particular, the one axial end of the output side engaging portion 19 is inserted without rattle into the other axial side portion of the first through hole 41a.

[0181] In this example, the small diameter shaft portion 21b constituting the output member 4b does not have a locking groove on its outer circumferential surface.

[0182] In this example, the input member 3 has an input member side restricting portion 59 that restricts the holding member 6d from moving toward one axial side relative to the output member 4b by engaging with the first spacer portion 38d. In this example, the input member side restricting portion 59 is formed by the radially inner end portion of the end face on the other axial side of the input shaft portion 15.

[0183] In this example, movement of the retaining member 6d relative to the output member 4b toward one axial side is restricted by a side surface on one axial side of the first spacer portion 38d abutting against or closely facing the input member side restricting portion 59. In contrast, movement of the retaining member 6d relative to the output member 4b toward the other axial side is restricted by a side surface on the other axial side of the second spacer portion 39 abutting against or closely facing an end face 63 on one axial side of the output shaft portion 20.

[0184] In this example, with regard to the axial position restriction structure of the retaining member 6d relative to the output member 4b, the retaining member 6d does not have an engagement protrusion and the output member 4b does not have an engagement groove, so that the structures of the retaining member 6d and the output member 4b can be simplified.

[0185] When implementing the structure of the present disclosure, if the first spacer portion of the retaining member does not include a locking protrusion as in this example, the halves on both axial sides of the retaining member can be shaped symmetrically to prevent erroneous installation of the retaining member during assembly. In other words, if the halves on both axial sides of the retaining member are shaped symmetrically to prevent erroneous installation of the retaining member during assembly, the retaining member can be properly assembled regardless of the axial orientation of the retaining member.

[0186] When implementing the structure of the present disclosure, if the first spacer portion of the retaining member does not have a locking protrusion as in this example, then, from the standpoint of preventing incorrect assembly of the retaining member during assembly work, the axial halves of the retaining member can be intentionally made asymmetrical in shape to make it easier for assembly workers and assembly equipment to recognize the axial orientation of the retaining member.

[0187] A specific embodiment for making the axially opposite halves of the holding member asymmetrical with respect to each other is not particularly limited. For example, the axial thickness of the first spacer portion and the axial thickness of the second spacer portion can be made different from each other to an extent that an assembly worker or a robot can easily recognize them. That is, as in this example, the axial thickness of the first spacer portion 38d can be made larger than the axial thickness of the second spacer portion 39, or the axial thickness of the second spacer portion can be made larger than the axial thickness of the first spacer portion. As in this example, a chamfered portion can be provided only on the second spacer portion 39 at the opening edge portion of the through hole.

[0188] When implementing the present disclosure, regardless of the presence or absence of the locking protrusion, the axial thickness of the first spacer portion and the second spacer portion can be set arbitrarily as long as the strength and function required for the holding member can be secured. The smaller the axial thickness of the first spacer portion and the second spacer portion, the more it can contribute to shortening the axial dimension of the reverse input cutoff clutch. For example, in the structure of this example, the axial thickness of the first spacer portion 38d is larger than the axial thickness of the second spacer portion 39, but if the axial thickness of the first spacer portion 38d is set to be equal to or smaller than the axial thickness of the second spacer portion 39, it can contribute to shortening the axial dimension of the reverse input cutoff clutch accordingly. The configuration and the action and effect of the other parts of the sixth example are the same as those of the first example.

[0189] [Example 7] A seventh example of the embodiment of the present disclosure will be described with reference to Figures 16(a) and 16(b). In this example, the structure for restricting the axial position of the holding member 6e relative to the output member 4 is different from that of the sixth example.

[0190] In this example, the structure of the retaining member 6e differs from that of the retaining member 6d of the sixth example only in that the axial thickness of the first spacer portion 38e is smaller than that of the sixth example. In this example, with the retaining member 6e assembled to the output member 4, one axial end of the output-side engaging portion 19 is inserted into the entire first through-hole 41a without any rattling.

[0191] The reverse input cutoff clutch of this example further includes a segmented annular retaining ring 60. A radially inner portion of the retaining ring 60 is engaged with a retaining groove 25 provided in a portion of the outer circumferential surface of the small diameter shaft portion 21 of the output member 4 that is located on one axial side of the first spacer portion 38e, more specifically, in this example, in an end portion on the other axial side of the outer circumferential surface of the small diameter shaft portion 21.

[0192] In this example, the first spacer portion 38e engages with the side surface on the other axial direction side of the radially outer portion of the retaining ring 60, thereby restricting movement of the retaining member 6e to one axial direction side relative to the output member 4. The manner in which movement of the retaining member 6e to the other axial direction side relative to the output member 4 is restricted is the same as in the sixth example.

[0193] In this example, the structure of the retaining member 6e can be simplified with respect to the axial position restriction structure of the retaining member 6e relative to the output member 4 because the retaining member 6e does not include a locking protrusion. In the assembly work of the reverse input cutoff clutch, at the stage where the retaining member 6e and the retaining ring 60 are attached to the output member 4, the retaining ring 60 can restrict the movement of the retaining member 6e to one side in the axial direction relative to the output member 4, making it easier to carry out the subsequent assembly process.

[0194] When implementing the present disclosure, if a structure is adopted in which a retaining member is prevented from moving in one axial direction by a stop ring as in this example, the same retaining member as in Example 6 can be used. However, if the axial thickness of the first spacer portion 38e constituting the retaining member 6e is made smaller than that in Example 6 as in this example, this can contribute to shortening the axial dimension of the reverse input cutoff clutch accordingly.

[0195] When implementing the present disclosure, even if a structure is adopted in which the movement of the retaining member to one side in the axial direction is restricted by a stop ring as in this example, from the viewpoint of preventing or suppressing erroneous assembly of the retaining member, various aspects can be adopted for making the halves of the retaining member on both axial sides symmetrical in shape or making the halves of the retaining member on both axial sides asymmetrical in shape, as in Example 6. The configuration and effects of the other parts of Example 7 are the same as those of Example 6.

[0196] [Example 8] An eighth example of the embodiment of the present disclosure will be described with reference to Figures 17(a) and 17(b). This example differs from the seventh example in the structure for restricting the axial position of the holding member 6f relative to the output member 4c.

[0197] In this example, the structure of the holding member 6f differs from that of the seventh example only in that the holding member 6f has locking protrusions 43b at two circumferential positions on the inner peripheral surface of the first through hole 41a of the first spacer portion 38f. In this example, the locking protrusions 43b are provided on both sides of the first spacer portion 38f in the short direction of the first spacer portion 38f among the ends on the other axial side of the inner peripheral surface of the first through hole 41a so as to extend in the longitudinal direction of the first spacer portion 38f. In this example, the radially inner portion of the side surface on the other axial side of each locking protrusion 43b is provided with an inclined surface portion 44a that functions as a guide surface during assembly.

[0198] In this example, in the output member 4c, the small diameter shaft portion 21b does not have a locking groove on the outer circumferential surface, and the output side engagement portion 19a has locking grooves 25a with which the respective locking protrusions 43b are locked at positions aligned with the two locking protrusions 43b on the outer circumferential surface, specifically, at the ends on one axial side of the two flat surfaces 23. The two locking protrusions 43b are locked to the two locking protrusions 43b.

[0199] In this example, the movement of the holding member 6f to one axial side relative to the output member 4c is restricted by the side surfaces of the two locking protrusions 43b on one axial side abutting against the side surface on one axial side that constitutes part of the inner surface of the locking groove 25a. The manner in which the movement of the holding member 6f to the other axial side relative to the output member 4c is restricted is the same as in the sixth example. The configurations and effects of the other parts are the same as in the seventh example.

[0200] [Case No. 9] A ninth example of the embodiment of the present disclosure will be described with reference to Figures 18(a), 18(b) and 18(c). In this example, the structure of a holding member 6g is different from that of the sixth example.

[0201] In this example, the holding member 6g is formed by assembling a plurality of parts.

[0202] More specifically, in this example, the holding member 6g is formed by assembling a first spacer portion 38g, a second spacer portion 39a, and two connection portions 40a, which are independent parts from each other.

[0203] The first spacer portion 38g and the second spacer portion 39a are each configured in a flat plate shape, and have a substantially oval or substantially rectangular end face shape when viewed in the axial direction.

[0204] The first spacer portion 38g has a first through hole 41a penetrating in the axial direction in the center, and has connection holes 61a penetrating in the axial direction at both ends in the longitudinal direction.

[0205] The second spacer portion 39a has a second through hole 46 penetrating in the axial direction in the center, and has connection holes 61b penetrating in the axial direction at both ends in the longitudinal direction.

[0206] The two connection portions 40a are each configured as a stepped cylinder having a small diameter portion 62 at both axial ends.

[0207] The retaining member 6g is assembled by press-fitting and fixing the small diameter portions 62 on one axial side of the two connecting portions 40a into the connecting holes 61a on both axial sides of the first spacer portion 38g, and by press-fitting and fixing the small diameter portions 62 on the other axial side of the two connecting portions 40a into the connecting holes 61b on both axial sides of the second spacer portion 39a, respectively.

[0208] In this example, the components 38g, 39a, and 40a that constitute the holding member 6g each have a simple shape, so that the manufacturing costs of these components 38g, 39a, and 40a can be reduced.

[0209] When implementing the present disclosure, even if a structure in which the holding member is made up of multiple parts as in this example is adopted, from the viewpoint of preventing or suppressing incorrect assembly of the holding member, various aspects can be adopted for making the halves on both axial sides of the holding member symmetrical in shape or making the halves on both axial sides of the holding member asymmetrical in shape, as in Example 6. The configurations and effects of the other parts of Example 9 are the same as those of Example 6.

[0210] [Case 10] A tenth example of the embodiment of the present disclosure will be described with reference to Figures 19 to 21(b). In this example, the structures of a biasing member 47a and a holding member 6h are different from those of the first example.

[0211] In this example, the urging member 47a is composed of two urging members 47a arranged on both sides of the holding member 6h in the second direction between the two engagement elements 5. Each of the two urging members 47a is composed of a compression coil spring 69. The compression coil spring 69 constituting each of the urging members 47a is held by inserting the protrusions 37 provided on the two engagement elements 5 into both axial sides of the compression coil spring 69. Each of the two compression coil springs 69 is elastically compressed in the first direction between the two engagement elements 5.

[0212] In this example, in the holding member 6h, the distance between the side surface on the other axial direction side of the first spacer portion 38h and the side surface on one axial direction side of the second spacer portion 39b is set to a value slightly larger than the axial thickness of the engaging element 5. As a result, in this example, the axial movement of the engaging element 5 is restricted directly by the first spacer portion 38h and the second spacer portion 39b, without via the biasing member 47a.

[0213] In this example, the axial thickness of the first spacer portion 38h and the second spacer portion 39b constituting the retaining member 6h is larger than that of the first example, but when implementing the present disclosure, the axial thickness of the first spacer portion 38h and the second spacer portion 39b can be made smaller than that of this example, for example, the axial thickness can be made the same as that of the first example. In this way, it is possible to contribute to shortening the axial dimension of the reverse input cutoff clutch accordingly.

[0214] In this example, the outer diameter Dc of each of the two compression coil springs 69 is constant over the entire length of the compression coil spring 69 in the extension direction. The extension direction of the compression coil spring 69 is the axial direction of the compression coil spring 69, which in this example coincides with the first direction in the assembled state of the reverse input cutoff clutch. The outer diameter Dc of each of the two compression coil springs 69 varies depending on the compression amount of the compression coil spring 69, but in the application of this example, the amount of change is negligibly small.

[0215] In this example, in the assembled state of the reverse input cutoff clutch, the outer diameter Dc of each compression coil spring 69 is larger than the axial thickness T5 of the engagement element 5 (Dc>T5). However, when implementing the present disclosure, in the assembled state of the reverse input cutoff clutch 1a, the outer diameter Dc of each compression coil spring 69 can also be set to be equal to or smaller than the axial thickness T5 of the engagement element 5 (Dc≦T5). By adopting such a dimensional relationship (Dc≦T5), it is possible to prevent the extension direction end of each compression coil spring 69 from being biasedly abutted against the flat surface portion 36 of the engagement element 5, and therefore it becomes easier to prevent the central axis of each compression coil spring 69 from being tilted with respect to the first direction.

[0216] The assembly method of the reverse input cutoff clutch of this example can also include a step of combining the output member 4, the two engaging members 5, the holding member 6h, and the two biasing members 47a, and using an assembly jig (not shown) that engages the input-side engaged portion 33 of the two engaging members 5, displacing the two engaging members 5 in a direction in which they approach each other in the radial direction against the elastic biasing forces of the two biasing members 47a, and then inserting the two engaging members 5 from the axial direction into the radially inner side of the pressed surface 7. This makes it easy to assemble the reverse input cutoff clutch of this example. The configurations and effects of the other parts of the tenth example are the same as those of the first example.

[0217] [Case 11] An eleventh example of the embodiment of the present disclosure will be described with reference to Figures 22 to 26(b). In this example, the structure of a holding member 6i is different from that of the tenth example.

[0218] In the reverse input cut-off clutch 1a of this example, the connection portion 40b of the retaining member 6i is composed of two connection portions 40b arranged on either side of the first spacer portion 38i and the second spacer portion 39c in the second direction, each connecting the first spacer portion 38i and the second spacer portion 39c, and each having a retaining hole 68 extending in the first direction.

[0219] Each connecting portion 40b is not particularly limited in shape as long as it connects the first spacer portion 38i and the second spacer portion 39c, has a retaining hole 68 extending in the first direction, and is configured so as not to impede the movement of other components when the reverse input cutoff clutch 1a is in use. In this example, each connecting portion 40b is configured in a flat plate shape with the first direction as the thickness direction, and has a substantially rectangular end face shape when viewed from the first direction.

[0220] In this example, the holding hole 68 of each connection portion 40b is configured as a through hole that passes through the center of the connection portion 40b in the first direction. In this example, each through hole is configured as a circular hole.

[0221] In this example, the axially opposite ends of the ends of each connection portion 40b that are close to each other in the second direction are integrally connected to the short-side (first direction) center of the respective longitudinal (second direction) ends of the first spacer portion 38i and the second spacer portion 39c.

[0222] In the reverse input cutoff clutch 1a of this example, two compression coil springs 69 constituting the two biasing members 47a are fitted and held within the holding holes 68 of the two connection portions 40b.

[0223] In addition, when implementing the present disclosure and the engaging element is configured with a single engaging element, each of the retaining holes provided at the two connection portions of the retaining member can be configured with a bottomed hole that opens only toward the engaging element in the first direction, and each of the two compression coil springs can be arranged so as to be elastically compressed between the bottom of the bottomed hole and the engaging element.

[0224] In this example, in the assembled state of the reverse input cutoff clutch 1a, the outer diameter Dc of each of the two compression coil springs 69 is slightly smaller than the inner diameter of the retaining hole 68. The intermediate portion of each of the two compression coil springs 69 in the extension direction is fitted into the retaining hole 68 without any radial wobble, thereby restricting movement of the springs in a direction perpendicular to the first direction relative to the output member 4.

[0225] In this example, the engaging element 5 does not have a protrusion 37 (see Figures 19 and 20) on its radially inner surface. In this example, the radially inner surface of the engaging element 5 is entirely formed of a flat surface portion 36 that is perpendicular to the radial direction of the engaging element 5. The output side engaged portion 34 is formed by the widthwise central portion of the flat surface portion 36. In the structure of this example, since it is not necessary to provide the engaging element 5 with a portion for holding the two compression coil springs 69, the shape of the engaging element 5 can be simplified and the manufacturing costs of the engaging element 5 can be reduced.

[0226] The method of assembling the reverse input cutoff clutch 1a of this example can also include a step of combining the output member 4, the two engaging elements 5, the holding member 6i, and the two compression coil springs 69, and, using an assembly jig (not shown) that engages the input-side engaged portion 33 of the two engaging elements 5, displacing the two engaging elements 5 in a direction in which they approach each other in the radial direction against the elastic biasing forces of the two compression coil springs 69, and then inserting the two engaging elements 5 from the axial direction into the radially inner side of the pressed surface 7. This makes it easy to assemble the reverse input cutoff clutch 1a of this example. The configurations and effects of the other parts of the eleventh example are the same as those of the tenth example.

[0227] [Case 12] A twelfth example of the embodiment of the present disclosure will be described with reference to Fig. 27. In this example, the shape of the small diameter shaft portion 21a of the output member 4a is different from that of the eleventh example.

[0228] In this example, the small diameter shaft portion 21a has a shape similar to that of the second example, and the assembly structure of the small diameter shaft portion 21a relative to the input shaft portion 15 of the input member 3 and the assembly structure of the first spacer portion 38i relative to the small diameter shaft portion 21a are also similar to those of the second example.

[0229] Therefore, in this example as well, the workability of assembling the reverse input cutoff clutch can be improved for the same reason as in Example 2. The configuration and effects of the other parts of the twelfth example are the same as those of the eleventh example.

[0230] [Case 13] A thirteenth example of the embodiment of the present disclosure will be described with reference to Fig. 28. In this example, the shape of a first spacer portion 38j constituting a holding member 6j is different from that of the eleventh example.

[0231] In this example, similarly to the third example, the first spacer portion 38j has discontinuous portions 45 at two locations in the circumferential direction of the first through-hole 41. More specifically, the discontinuous portions 45 are provided at two locations located on both sides in the short direction (first direction) of the center portion in the longitudinal direction (second direction) of the first spacer portion 38j.

[0232] Therefore, in this example as well, the workability of assembling the reverse input cutoff clutch can be improved for the same reason as in Example 3. The configuration and effects of the other parts of the thirteenth example are the same as those of the eleventh example.

[0233] [Case 14] A fourteenth example of the embodiment of the present disclosure will be described with reference to Fig. 29. In this example, the shape of a first spacer portion 38k constituting a holding member 6k is different from that of the eleventh example.

[0234] In this example, similar to the fourth example, the first spacer portion 38k does not have any discontinuous portion anywhere in the circumferential direction of the first through hole 41, and is continuous around the entire circumference. Instead, in this example, the locking protrusions 43a are provided in a plurality of circumferentially separated positions on the inner circumferential surface of the first through hole 41 in the first spacer portion 38k. In this example, an inclined surface portion 44 that functions as a guide surface during assembly is provided on the radially inner portion of the side surface on the other axial side of each of the locking protrusions 43a.

[0235] Therefore, in this example as well, the workability of assembling the reverse input cutoff clutch can be improved for the same reason as in Example 4. The configuration and effects of the other parts of the 14th example are the same as those of the 11th example.

[0236] [Case 15] A fifteenth example of the embodiment of the present disclosure will be described with reference to Fig. 30. In this example, the shape of a first spacer portion 38l constituting a holding member 6l is different from that of the eleventh example.

[0237] In this example, similar to the fifth example, the first spacer portion 38l has discontinuous portions 45 at two circumferential locations, located on both sides in the short direction (first direction) of the longitudinal (second direction) center of the first spacer portion 38l, and is provided with locking protrusions 43a at multiple locations circumferentially spaced apart on the inner surface of the first through hole 41.

[0238] Therefore, in this example as well, the workability of assembling the reverse input cutoff clutch can be further improved for the same reasons as in Example 5. The configuration and effects of the other parts of the 15th example are the same as those of the 11th example.

[0239] [Case 16] A sixteenth example of the embodiment of the present disclosure will be described with reference to Fig. 31. In this example, the shape of two connecting portions 40c that configure a holding member 6m is different from that of the fifteenth example.

[0240] Each of the two connection portions 40c has a discontinuous portion 70 at one location in the circumferential direction of the retaining hole 68. The discontinuous portion 70 opens to the inner circumferential surface of the retaining hole 68, the outer circumferential surface of the connection portion 40c, and both side surfaces in the thickness direction (first direction). Therefore, the inner circumferential surface of the retaining hole 68 is discontinuous in the circumferential direction at the location where the discontinuous portion 70 exists. In this example, the discontinuous portion 70 is provided in the axial center of the end portion of the connection portion 40c that is on the central side of the retaining member 6d in the second direction.

[0241] In addition, when implementing the present disclosure, the discontinuous portion 70 may be provided in only one of the two connection portions constituting the holding member. In addition, the circumferential position of the discontinuous portion 70 provided in the connection portion may be a circumferential position different from that in this example.

[0242] In the structure of this example, when the first through-hole 41 is elastically expanded or contracted, two portions of each of the connection portions 40c that face each other in the axial direction with the discontinuous portion 70 therebetween are relatively displaced, thereby reducing the expansion / contraction rigidity of the first through-hole 41. Therefore, when the holding member 6d is assembled to the output member 4 (see Figs. 24(a) and 24(b)), the work of moving the outer circumferential surface of the small diameter shaft portion 21 in the axial direction while elastically expanding the diameter of the inscribed circle of the plurality of locking protrusions 43a can be made easier, thereby further improving the ease of assembly of the reverse input cutoff clutch. The configurations and effects of the other portions of the 16th example are the same as those of the 15th example.

[0243] [Case 17] A seventeenth example of the embodiment of the present disclosure will be described with reference to Fig. 32. In this example, the circumferential positions of the discontinuous portions 70 provided in the respective connection portions 40d that constitute the holding member 6n are different from those in the sixteenth example.

[0244] Specifically, in each connection portion 40d, the discontinuous portion 70 is provided in the axial center of the end portion farther from the center of the holding member 6d in the second direction. The configuration and effects of the other portions of the seventeenth example are similar to those of the fifteenth example.

[0245] [Case 18] An 18th example of the embodiment of the present disclosure will be described with reference to Figures 33(a) and 33(b). In this example, the structure for restricting the axial position of the holding member 60 relative to the output member 4b is different from that of the 11th example.

[0246] In this example, the position restriction structure is the same as that in the sixth example. That is, in this example, the holding member 6о does not have a locking protrusion, and the output member 4b does not have a locking groove. In this example, the first spacer portion 38m in the holding member 6о has a first through hole 41a through which the output side engagement portion 19 is inserted without rattling. In this example, the movement of the holding member 6о to one axial side relative to the output member 4b is restricted by a side surface on one axial side of the first spacer portion 38m abutting or closely facing the input member side restriction portion 59 of the input member 3. On the other hand, the movement of the holding member 6о to the other axial side relative to the output member 4b is restricted by a side surface on the other axial side of the second spacer portion 39c abutting or closely facing the end face 63 on one axial side of the output shaft portion 20.

[0247] In this example, as in the sixth example, the structure of the holding member 6о and the output member 4b can be simplified because the holding member 6о does not have a locking protrusion and the output member 4b does not have a locking groove with respect to the position restriction structure. The configuration and effects of the other parts of the eighteenth example are the same as those of the eleventh example.

[0248] [Case 19] A nineteenth example of the embodiment of the present disclosure will be described with reference to Fig. 34. In this example, the structure for restricting the axial position of the holding member 6p with respect to the output member 4 is different from that of the eighteenth example.

[0249] In this example, the same structure as that of the seventh example is adopted as the position restriction structure. That is, in this example, the structure of the holding member 6p differs from that of the holding member 6о of the eighteenth example only in that the axial thickness of the first spacer portion 38n is slightly smaller than that of the eighteenth example. The reverse input cutoff clutch of this example further includes a snap ring 60 having a segmented annular shape. The radially inner portion of the snap ring 60 is engaged with a locking groove 25 provided at the end of the outer circumferential surface of the small diameter shaft portion 21 of the output member 4 on the other axial side. In this example, the first spacer portion 38n of the holding member 6p engages with the side surface of the radially outer portion of the snap ring 60 on the other axial side, thereby restricting the movement of the holding member 6p to one axial side relative to the output member 4. The manner in which the movement of the holding member 6p to the other axial side relative to the output member 4 is restricted is the same as that of the eighteenth example.

[0250] In this example, as in the seventh example, the structure of the holding member 6p is simplified because the holding member 6p does not have a locking protrusion with respect to the position restriction structure. The configurations and effects of the other parts of the 19th example are the same as those of the 18th example.

[0251] [Case 20] A twentieth example of the embodiment of the present disclosure will be described with reference to Figures 35(a) and 35(b). This example differs from the 19th example in the structure for restricting the axial position of the holding member 6q relative to the output member 4c.

[0252] In this example, the position restriction structure is the same as that in the eighth example. That is, in this example, the structure of the holding member 6q is different from that in the nineteenth example only in that the holding member 6q has locking protrusions 43b at two circumferential positions on the inner peripheral surface of the first through hole 41a of the first spacer portion 38о. In this example, the locking protrusions 43b are provided on both sides of the short direction (first direction) of the first spacer portion 38о in an axial portion (axial middle portion in the illustrated example) of the inner peripheral surface of the first through hole 41a so as to extend in the longitudinal direction (second direction) of the first spacer portion 38о. In this example, the radially inner portion of the side surface on the other axial side of each locking protrusion 43b is provided with an inclined surface portion 44a that functions as a guide surface during assembly.

[0253] In this example, in the output member 4c, the small diameter shaft portion 21b does not have a locking groove on the outer circumferential surface, and the output side engagement portion 19a has locking grooves 25a with which the respective locking protrusions 43b are locked at positions aligned with the two locking protrusions 43b on the outer circumferential surface, specifically, at the ends on one axial side of the two flat surfaces 23. The two locking protrusions 43b are locked to the two locking protrusions 43b.

[0254] In this example, the movement of the holding member 6q to one axial side relative to the output member 4c is restricted by the side surfaces on one axial side of the two locking protrusions 43b abutting against the side surface on one axial side that constitutes part of the inner surface of the locking groove 25a. The manner in which the movement of the holding member 6q to the other axial side relative to the output member 4c is restricted is the same as in the 19th example. The configurations and effects of the other parts are the same as in the 19th example.

[0255] [Case 21] A twenty-first example of the embodiment of the present disclosure will be described with reference to Figures 36 and 37. In this example, the structure for restricting the axial position of the holding member 6r relative to the output member 4d is different from that of the eighteenth example.

[0256] This example differs from the 18th example in that the locking protrusion 43c, which is engaged with the locking groove 25b of the output member 4d, is provided on the side of one of the two connection portions 40e of the retaining member 6r that faces the output side engagement portion 19 in the second direction.

[0257] More specifically, in this example, the locking protrusion 43c is provided at a middle portion in the first direction of an axial middle portion of a side surface of each connecting portion 40e that faces the output side engaging portion 19 in the second direction. In this example, the whole of the side surface on the other axial side of the locking protrusion 43c is formed of an inclined surface portion 44b that functions as a guide surface during assembly. Also, the side surface on one axial side of the locking protrusion 43c is formed of a plane perpendicular to the axial direction.

[0258] In this example, the locking groove 25b is formed across the entire circumferential width at the same axial position as the two locking protrusions 43c, among the two convex curved surfaces 24 that constitute the outer peripheral surface of the output side engagement portion 19, and has a rectangular cross-sectional shape.

[0259] The retaining member 6r is attached to the output member 4d with the other axial end of the output side engaging portion 19 inserted without rattle into the second through hole 46 of the second spacer portion 39c, and the one axial end of the output side engaging portion 19 inserted without rattle into the first through hole 41a of the first spacer portion 38n, and the two locking protrusions 43c engaged with the two locking grooves 25b.

[0260] In this example, the movement of the holding member 6r to one axial side relative to the output member 4d is restricted by the side surface on one axial side of the locking protrusion 43c abutting against the side surface 67a facing the other axial side of the inner surface of the locking groove 25b. The manner in which the movement of the holding member 6r to the other axial side relative to the output member 4d is restricted is the same as in the 18th example. The configurations and effects of the other parts are the same as in the 18th example.

[0261] [Case 22] A twenty-second example of the embodiment of the present disclosure will be described with reference to FIGS. 38(a) to 39. FIG.

[0262] The reverse input cutoff clutch of this example includes a pressing piece 71 attached to the end of the compression coil spring 69 in the extension direction for each of the two compression coil springs 69. Each of the two compression coil springs 69 elastically presses both side portions in the second direction of the flat surface portion 36 constituting the radial inner surface of the engagement member 5 via the pressing piece 71.

[0263] Although not limited thereto, in this example, the pressing piece 71 has a stepped cylindrical shape composed of a coaxially arranged large diameter portion 72 and small diameter portion 73. A tip surface 74 of the large diameter portion 72 in the axial direction of the pressing piece 71 and a step surface 75 connecting the outer circumferential surface of the large diameter portion 72 and the outer circumferential surface of the small diameter portion 73 are each composed of a flat surface perpendicular to the central axis of the pressing piece 71.

[0264] In this example, a pressure piece 71 is attached to each end of each compression coil spring 69 on both sides in the extension direction.

[0265] The pressing piece 71 is attached to the extension direction end of the compression coil spring 69 in such a manner that the small diameter portion 73 is inserted into the extension direction end of the compression coil spring 69 and the stepped surface 75 is abutted against the extension direction edge of the compression coil spring 69, and the tip surface 74 is in surface contact with the flat surface portion 36 of the engagement member 5. In this state, the compression coil spring 69 elastically presses the stepped surface 75 of the pressing piece 71, thereby elastically pressing the flat surface portion 36 of the engagement member 5 via the pressing piece 71.

[0266] In this example, the outer peripheral surface of the pressing piece 71 is fitted into the inner peripheral surface of the holding hole 68 of the holding member 6 so as to be slidable in the extension direction (first direction) of the holding hole 68. Specifically, the outer peripheral surface of the large diameter portion 72 of the pressing piece 71 is fitted into the inner peripheral surface of the holding hole 68 so as to be slidable in the extension direction of the holding hole 68 without any rattling in the radial direction of the holding hole 68. The state in which the outer peripheral surface of the large diameter portion 72 of the pressing piece 71 is fitted into the inner peripheral surface of the holding hole 68 is always maintained, and specifically, this is maintained not only in the unlocked state in which the engaging piece 5 has moved to the innermost position in the radial direction as shown in Figs. 6 and 38(a) but also in the locked state or semi-locked state in which the engaging piece 5 has moved to the outermost position in the radial direction as shown in Figs. 7 and 38(b).

[0267] In this example, each compression coil spring 69 elastically presses against the flat surface portion 36 of the engaging member 5 via the pressing piece 71, thereby ensuring a wide pressing area against the flat surface portion 36 and enabling stable pressing against the flat surface portion 36.

[0268] In this example, the outer peripheral surface of the pressing piece 71 is fitted into the inner peripheral surface of the retaining hole 68 so as to be able to slide in the extension direction of the retaining hole 68, and both ends of the compression coil spring 69 in the extension direction do not protrude in the extension direction from the inside of the retaining hole 68. Therefore, even if the compression coil spring 69 is deformed due to centrifugal force generated when the input member 3 rotates, the compression coil spring 69 can be prevented from getting caught on the periphery of the opening of the retaining hole 68.

[0269] In other words, if the pressure piece 71 is not provided, and the bending rigidity of the compression coil spring 69 is low, the centrifugal force generated when the input member 3 rotates will cause the ends of the compression coil spring 69 on both sides in the extension direction thereof, which protrude from the retaining hole 68, to elastically deform radially outward (to the left in FIG. 39) about the central axis of rotation of the input member 3, as shown in an exaggerated manner in FIG. 39, and get caught on the opening peripheral portion of the retaining hole 68 (part P in FIG. 39), which may cause inconvenience such as the compression of the compression coil spring 69 not being able to be smoothly performed.

[0270] In this example, the ends on both sides of the compression coil spring 69 in the extension direction do not protrude from the inside of the retaining hole 68 in the extension direction, so that the above-mentioned inconvenience can be prevented and the compression coil spring 69 can be smoothly compressed regardless of the centrifugal force. Therefore, an appropriate spring force can be applied to the engagement piece 5. The other configurations and effects of the 22nd example are similar to those of the 11th example.

[0271] [Case 23] A 23rd example of an embodiment of the present disclosure will be described with reference to FIG.

[0272] In the reverse input cutoff clutch of this example, guide surface portions 76, the inner diameter of which increases toward the opening side, are provided at both opening side ends in the extension direction of the inner circumferential surface of each of the retaining holes 68a constituting the retaining member 6s. In this example, the guide surface portions 76 have a convex arc-shaped cross section. However, when implementing this disclosure, the cross section of the guide surface portions may also be linear, as indicated by the two-dot chain line α in FIG.

[0273] In this example, the inner peripheral surface of the retaining hole 68a is provided at the opening side end on both sides in the extension direction with a guide surface portion 76 having an inner diameter that increases toward the opening side. Therefore, during assembly work, the compression coil spring 69 can be easily inserted into the inside of the retaining hole 68a. In addition, even if the ends of the compression coil spring 69 on both sides in the extension direction are elastically deformed toward the radially outward side (left side in FIG. 40) around the rotation center axis due to the centrifugal force generated when the reverse input cutoff clutch rotates, the portions are unlikely to get caught on the opening periphery of the retaining hole 68a (part P in FIG. 40). Therefore, an appropriate spring force can be applied to the engaging piece. The other configurations and effects of the 23rd example are the same as those of the 11th example.

[0274] [Case 24] A 24th example of the embodiment of the present disclosure will be described with reference to FIG.

[0275] In the reverse input cutoff clutch of this example, the outside diameter of each compression coil spring 69a becomes smaller from the middle portion toward both sides in the extension direction of the compression coil spring 69a.

[0276] Therefore, during assembly work, the compression coil spring 69a can be easily inserted into the retaining hole 68 of the retaining member 6i. Also, due to the low bending rigidity of the compression coil spring 69a, even if the ends on both sides of the extension direction of the compression coil spring 69a are elastically deformed toward the radially outward direction (left side in FIG. 41) about the rotation center axis due to the centrifugal force generated when the reverse input cutoff clutch rotates, the portions are unlikely to get caught on the opening periphery of the retaining hole 68a (part P in FIG. 41). Therefore, an appropriate spring force can be applied to the engaging piece. The other configurations and effects of the 24th example are the same as those of the 11th example.

[0277] The reverse input cutoff clutch of the present disclosure can be embodied by appropriately combining the structures of the first to twenty-fourth examples within a range in which no contradiction occurs. [Explanation of symbols]

[0278] 1, 1a Reverse input cutoff clutch 2 Pressurized member 3 Input member 4, 4a, 4b, 4c, 4d Output members 5, 5a, 5b engager 6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j, 6k, 6l, 6m, 6n, 6о, 6p, 6q, 6r, 6s Retaining member 7 Pressed surface 8 Output side element 9 Large diameter cylindrical surface 10 Small diameter cylindrical surface part 11 Connection surface 12 Inward flange 13 Screw hole 14 Input side engagement portion 15 Input shaft 16 Radial inner surface 17 Radial outer surface 18 Circumferential side 19 Output side engagement part 20 Output shaft 21, 21a, 21b Small diameter shaft part 22 Output flange 23 Flat surface 24 Convex curved surface 25, 25a, 25b locking groove 26 Radial Rolling Bearing 27 Outer Ring 28a, 28b Retaining ring 29 Inner Circle 30 Rolling elements 31 Plain bearings 32 Pressing surface 33, 33a, 33b Input side engaged part 34 Output side engaged part 35 Radial inner surface 36 Flat surface part 37 Convex 38, 38a, 38b, 38c, 38d, 38e, 38f, 38g, 38h, 38i, 38j, 38k, 38l, 38m, 38n, 38о First spacer part 39, 39a, 39b, 39c Second spacer part 40, 40a, 40b, 40c, 40d, 40e Connections 41, 41a 1st through hole 42 Engagement recess 43, 43a, 43b, 43c Locking protrusion 44, 44a, 44b Slope section 45 Discontinuity 46 2nd hole 47, 47a biasing member 48 Arm 49 Connecting part 50, 50a Spare assembly 51 Output side assembly 52 First spacer 53 Second spacer 54 Retaining ring 55 Through hole 56 Small diameter section 57 Large diameter section 58 Step surface 59 Input member side restriction portion 60 Retaining ring 61a, 61b Connection holes 62 Small diameter section 63 End face 64 Corner R 65 Chamfered part 66 End face 67, 67a side 68, 68a retaining hole 69, 69a Compression coil spring 70 Discontinuity 71 Pressing piece 72 Large diameter section 73 Small diameter section 74 Tip surface 75 Step surface 76 Guide surface section

Claims

1. A pressed member having a pressed surface on an inner circumferential surface thereof; an input member having an input side engagement portion arranged radially inside the pressed surface and arranged coaxially with the pressed surface; an output member having an output side engaging portion disposed radially inward relative to 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, the engaging element being 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; a retaining member having a first spacer portion, a second spacer portion, and a connecting portion connecting the first spacer portion and the second spacer portion, and attached to the output member in a state in which the engaging element is disposed between the first spacer portion and the second spacer portion in the axial direction, thereby restricting axial movement of the engaging element relative to the output member; Equipped with When a rotational torque is input to the input member, the engaging element moves in a direction away from the pressed surface in the first direction 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 reverse to the output member, the output side engaging portion engages with the output side engaged portion, and the pressing surface is pressed against the pressed surface, thereby frictionally engaging the pressing surface with the pressed surface. Reverse input cut-off clutch.

2. the output member has a small diameter shaft portion protruding from a center portion of an end surface on one axial side of the output side engagement portion toward the one axial side, the first spacer portion has a first through hole through which the output side engagement portion and / or the small diameter shaft portion is inserted, The second spacer portion has a second through hole through which the output side engagement portion is inserted.

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

3. the retaining member has a locking protrusion protruding from an outer circumferential surface of the output side engaging portion or a surface facing an outer circumferential surface of the small diameter shaft portion, the output side engagement portion or the small diameter shaft portion has an engagement groove in which the engagement protrusion is engaged, at the same axial position on the outer circumferential surface as the engagement protrusion; 3. The reverse input cutoff clutch according to claim 2.

4. 4. The reverse input cut-off clutch according to claim 3, wherein a side surface on the other axial direction side of the locking protrusion has an inclined surface portion at least in a tip end portion in the protruding direction of the locking protrusion, the inclined surface portion being inclined in a direction toward the one axial direction side as it approaches the tip end side in the protruding direction.

5. 5. The reverse input cutoff clutch according to claim 4, wherein the side surface on the one axial direction side of the locking protrusion is formed by a plane perpendicular to the axial direction of the pressed surface.

6. 4. The reverse input cutoff clutch according to claim 3, wherein the locking protrusions are provided at a plurality of locations spaced apart in the circumferential direction.

7. The reverse input cutoff clutch according to claim 3 , wherein the locking protrusion protrudes from an inner circumferential surface of the first through hole.

8. 8. The reverse input cutoff clutch according to claim 7, wherein the first spacer portion has a discontinuous portion at least at one location in the circumferential direction.

9. the outer circumferential surface of the small diameter shaft portion has a small diameter portion constituting one axial side portion, a large diameter portion constituting the other axial side portion, and a step surface facing one axial side and connecting the small diameter portion and the large diameter portion, an outer diameter of the small diameter portion is equal to or smaller than a diameter of an inscribed circle of the locking protrusion, The outer diameter of the large diameter portion is larger than the diameter of the inscribed circle of the locking protrusion, The locking groove is provided in the large diameter portion.

8. The reverse input cut-off clutch according to claim 7.

10. 3. The reverse input cutoff clutch according to claim 2, wherein the input member has an input member side restricting portion that restricts the holding member from moving toward the one axial side relative to the output member based on engagement with the first spacer portion.

11. a retaining ring having a radially inner portion engaged with a portion of an outer circumferential surface of the small diameter shaft portion that is located on one axial side of the first spacer portion, the first spacer portion engages with a side surface of the radially outer portion of the retaining ring on the other axial direction side, thereby restricting movement of the retaining member toward the one axial direction side relative to the output member.

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

12. 2. The reverse input cutoff clutch according to claim 1, further comprising a biasing member that elastically biases the engagement element in a direction approaching the pressed surface in relation to the first direction.

13. The reverse input cutoff clutch according to claim 12, wherein the axial movement of the biasing member relative to the output member is restricted by the holding member.

14. 14. The reverse input cut-off clutch according to claim 13, wherein the biasing member is disposed between the first spacer portion and the second spacer portion in the axial direction of the pressed surface, and is configured by a leaf spring elastically sandwiched between the output side engaging portion and the engaging element in the first direction.

15. the connection portion of the holding member is arranged on both sides of the first spacer portion and the second spacer portion in a second direction perpendicular to both the axial direction of the pressed surface and the first direction, and is configured by two connection portions each having a holding hole extending in the first direction, the biasing member is configured by two compression coil springs that are fitted and held in the retaining holes of the two connection portions and elastically press both side portions in the second direction of a side surface of the engaging element that is opposite to the pressed surface in the first direction.

14. The reverse input disconnect clutch according to claim 13.

16. a pressing piece attached to an end of each of the two compression coil springs in the extension direction of the compression coil spring; Each of the two compression coil springs elastically presses both side portions of the engagement piece via the pressing piece.

16. The reverse input disconnect clutch of claim 15.

17. The engaging element is composed of two engaging elements, The input side engagement portion is composed of two input side engagement portions, The retaining hole is configured as a through hole penetrating in the first direction, Each of the two compression coil springs is elastically compressed in the first direction between the two engagement elements.

16. The reverse input disconnect clutch of claim 15.

18. 18. The reverse input cutoff clutch according to claim 17, wherein at least one of the two connection portions has a discontinuous portion at one location in the circumferential direction of the retaining hole.

19. The engaging element is composed of two engaging elements, The input side engagement portion is composed of two input side engagement portions.

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

20. 20. A method for assembling a reverse input cutoff clutch according to claim 17 or 19, comprising: a biasing member that elastically biases the engagement element in a direction in which the engagement element approaches the pressed surface with respect to the first direction, the method comprising the steps of: the step of combining the output member, the two engaging elements, the holding member and the biasing member, and displacing the two engaging elements in a direction toward each other in the radial direction against the elastic biasing force of the biasing member using an assembly jig engaged with the input side engaged portions of the two engaging elements, and then inserting the two engaging elements from the axial direction into the radially inner side of the pressed surface. How to assemble a reverse input cutoff clutch.

Images