Reverse input blocking clutch and method for assembling same

Abstract

[Problem] To provide a structure of a reverse input blocking clutch that is capable of restricting axial movement of an engagement element with respect to an output member while reducing the number of components. [Solution] The present invention comprises a pressed member 2, an input member 3, an output member 4, an engagement element 5, and a holding member 6. The holding member 6 has a first spacer part 38, a second spacer part 39, and a connection part 40 that connects the first spacer part 38 and the second spacer part 39. The engagement element 5 is attached to the output member 4 in a state in which the engagement element 5 is disposed between the first spacer part 38 and the second spacer part 39 in the axial direction of a pressed surface 7, so that axial movement of the engagement element 5 with respect to the output member 4 is restricted.

Description

Reverse input cutoff clutch and assembly method thereof

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

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

[0003] Reverse input cutoff clutches are broadly classified into locking and free types depending on the mechanism that cuts off the rotational torque that is reversely input to the output member. A locking reverse input cutoff clutch is equipped with a mechanism that prevents the output member from rotating when rotational torque is reversely input to the output member. On the other hand, a free type reverse input cutoff clutch is equipped with a mechanism that causes the output member to spin freely when rotational torque is input to the output member. Whether to use a locking reverse input cutoff clutch or a free type reverse input cutoff clutch is determined appropriately depending on the application of the device into which the reverse input cutoff clutch is incorporated, etc.

[0004] International Publication No. 2023 / 136149 describes a locking type reverse input disconnection clutch. This conventional reverse input disconnection 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 disposed radially inside the pressed surface, and is disposed coaxially with the pressed surface.

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

[0008] The engaging element has a pressing surface facing the pressed surface, an input side engaged portion that can engage with the input side engaging portion, and an output side engaged portion that can engage 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 rotational torque is input to the input member, the input-side engaging portion engages with the input-side engaged portion, causing the engaging element to move in a direction away from the pressed surface and engaging the output-side engaged portion with the output-side engaging portion, thereby transmitting the rotational torque input to the input member to the output member. On the other hand, when rotational torque is reversely input to the output member, the output-side engaging portion engages with the output-side engaged portion, causing the engaging element to move in a direction approaching the pressed surface, pressing the pressing surface against the pressed surface and causing the pressing surface to frictionally engage with the pressed surface.

[0010] International Publication No. 2023 / 136149 Pamphlet

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

[0012] In this conventional reverse input cutoff clutch, two spacers 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 that are independent of each other increases the number of parts, which causes inconveniences such as an increase in the cost of managing the parts and an increase in the number of assembly steps.

[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.

[0015] A reverse input disconnecting clutch according to a first aspect of the present disclosure includes a pressed member, an input member, an output member, an engaging 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 disposed radially inside the pressed surface, and is disposed coaxially with the pressed surface.

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

[0019] The engaging element has a pressing surface facing the pressed surface, an input side engaged portion that can engage with the input side engaging portion, and an output side engaged portion that can engage with the output side engaging portion, and is arranged so as 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 the first direction away from the pressed surface based on the engagement of the input side engaging portion with the input side engaged portion, and transmits the rotational torque input to the input member to the output member by engaging the output side engaged portion with the output side engaging portion, whereas when a rotational torque is input in the reverse direction to the output member, the output side engaging portion engages with the output side engaged portion, and presses the pressing surface against the pressed surface, causing the pressing surface to frictionally engage with the pressed surface.

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

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

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

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

[0026] In the reverse input disconnection clutch according to the sixth aspect of the present disclosure, in the reverse input disconnection clutch according to any one of the third to fifth aspects of the present disclosure, the locking protrusions are provided at multiple locations spaced apart in the circumferential direction.

[0027] In the reverse input disconnection clutch according to the seventh aspect of the present disclosure, in the reverse input disconnection clutch according to any one of the third to sixth aspects of the present disclosure, the locking protrusion protrudes from the inner surface of the first through hole.

[0028] A reverse input disconnection clutch according to an eighth aspect of the present disclosure is the reverse input disconnection 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] A reverse input cutoff clutch according to a ninth aspect of the present disclosure is the reverse input cutoff clutch of the seventh aspect of the present disclosure, wherein the outer peripheral 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 stepped surface facing one axial side that connects the small diameter portion and the large diameter portion, the outer diameter of the small diameter portion is equal to or smaller than the diameter of the 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, and the locking groove is provided in the large diameter portion.

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

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

[0032] In the reverse input disconnection clutch according to the twelfth aspect of the present disclosure, in the reverse input disconnection clutch of any of the first to eleventh aspects of the present disclosure, a biasing member is provided that elastically biases the engaging element in a direction that brings it closer to the pressed surface in the first direction.

[0033] In a reverse input cut-off clutch according to one aspect of the present disclosure, in a reverse input cut-off clutch according to a twelfth aspect of the present disclosure, the engaging element is composed of two engaging elements, the input side engaging portion is composed of two input side engaging portions, and the biasing member is composed of two compression coil springs arranged between the two engaging elements on both sides 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 disconnection clutch according to a thirteenth aspect of the present disclosure is the reverse input disconnection 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 the reverse input disconnection clutch of the 14th aspect of the present disclosure, in the reverse input disconnection 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 sandwiched between the output side engaging portion and the engaging element in the first direction.

[0036] A reverse input cut-off clutch according to a fifteenth aspect of the present disclosure is a reverse input cut-off clutch according to the thirteenth aspect of the present disclosure, wherein the connection portion of the retaining 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 composed of two connection portions each having a retaining hole extending in the first direction, and 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, wherein each of the two compression coil springs is provided with a pressure piece attached to an end of the compression coil spring in the extension direction, and each of the two compression coil springs elastically presses both side portions of the engaging element via the pressure piece.

[0038] In a reverse input cut-off clutch according to one aspect of the present disclosure, in the reverse input cut-off clutch of the 16th aspect of the present disclosure, the outer surface of the pressure piece is fitted into the inner 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 disconnection clutch according to one aspect of the present disclosure, in a reverse input disconnection clutch according to either the 15th or 16th aspect 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 aspect of the present disclosure, in the reverse input disconnection clutch of the fifteenth or sixteenth aspect of the present disclosure, the outer diameters of the two compression coil springs become smaller from the middle portion toward both sides in the extension direction of the compression coil spring.

[0041] A reverse input disconnection clutch according to a seventeenth aspect of the present disclosure is a reverse input disconnection clutch according to the fifteenth or sixteenth aspect of the present disclosure, wherein the engaging element is composed of two engaging elements, the input side engaging portion is composed of two input side engaging portions, the retaining hole is composed of a through hole that penetrates in the first direction, and each of the two compression coil springs is elastically compressed in the first direction between the two engaging elements.

[0042] In the reverse input disconnection clutch of the 18th aspect of the present disclosure, in the reverse input disconnection 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] In a reverse input cutoff clutch according to a 19th aspect of the present disclosure, in the reverse input cutoff clutches of the first to 16th aspects of the present disclosure, the engaging element is composed of two engaging elements, and the input side engaging portion is composed of two input side engaging portions.

[0044] A method for assembling a reverse input cut-off clutch according to one aspect of the present disclosure is a method for assembling a reverse input cut-off clutch of the seventeenth or nineteenth aspect of the present disclosure that is equipped with the biasing member, and 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, displaces the two engaging elements in a direction that brings them closer to each other in the radial direction against the elastic biasing force of the biasing member, and then inserting the two engaging elements axially into the radially inner side of the pressed surface.

[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 a method for assembling the same.

[0046] FIG. 1 is a cross-sectional view of a reverse input cutoff clutch according to a first example of an embodiment of the present disclosure. FIG. 2 is an exploded perspective view of the reverse input cutoff clutch according to the first example. 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). FIG. 4 is a cross-sectional view taken along the line CC in FIG. 1, with some parts omitted. FIG. 5 is a cross-sectional view taken along the line DD in FIG. 1, with the retaining member and the biasing member omitted. FIG. 6 is a view similar to FIG. 5, showing a state in which rotational torque is input to the input member. FIG. 7 is a view similar to FIG. 5, showing a state in which rotational torque is reversely input to the output member. FIG. 8(a) is a perspective view of the retaining member according to the first example, as seen from one axial side, and FIG. 8(b) is a perspective view of the retaining member according to the first example, as seen from the other axial side. FIGS. 9(a) to 9(c) are cross-sectional views illustrating, in order of steps, a method of assembling an assembly constituting a part of the reverse input cutoff clutch according to the first example. 10(a) to 10(e) are cross-sectional views showing, in order of steps, an assembly method for an assembly constituting a part of a reverse input disconnection clutch of a comparative example compared to the first example. FIG. 11 is a view corresponding to the right side of FIG. 3(a) of a reverse input disconnection clutch of a second example embodiment of the present disclosure. FIGS. 12(a) and 12(b) are views corresponding to FIGS. 8(a) and 8(b) of a retaining member incorporated into a reverse input disconnection clutch of a third example embodiment of the present disclosure. FIGS. 13(a) and 13(b) are views corresponding to FIGS. 8(a) and 8(b) of a retaining member incorporated into a reverse input disconnection clutch of a fourth example embodiment of the present disclosure. FIGS. 14(a) and 14(b) are views corresponding to FIGS. 8(a) and 8(b) of a retaining member incorporated into a reverse input disconnection clutch of a fifth example embodiment of the present disclosure. Fig. 15(a) is a view corresponding to part A in Fig. 1 of a reverse input cutoff clutch according to a sixth example of an embodiment of the present disclosure, Fig. 15(b) is a perspective view of a holding member incorporated into the reverse input cutoff clutch as viewed from one axial side, Fig. 16(a) is a view corresponding to part A in Fig. 1 of a reverse input cutoff clutch according to a seventh example of an embodiment of the present disclosure, and Fig. 16(b) is a perspective view of a holding member incorporated into the reverse input cutoff clutch as viewed from one axial side.17(a) is a view corresponding to portion A in FIG. 1 of a reverse input cutoff clutch according to an eighth example of an embodiment of the present disclosure, and FIG. 17(b) is a perspective view of a retaining member incorporated into the reverse input cutoff clutch, as viewed from one axial side. FIG. 18(a) is a perspective view of a retaining member incorporated into a reverse input cutoff clutch according to a ninth example of an embodiment of the present disclosure, as viewed from one axial side. FIG. 18(b) is a cross-sectional view of the retaining member, and FIG. 18(c) is a view of the retaining member as viewed from the right of FIG. 18(b). 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. FIG. 20 is a view corresponding to FIG. 4 of the reverse input cutoff clutch according to the tenth example. FIG. 21(a) is a view corresponding to portion A in FIG. 1 of the reverse input cutoff clutch according to the tenth example, and FIG. 21(b) is a perspective view of a retaining member incorporated into the reverse input cutoff clutch, as viewed from one axial side. 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. FIG. 23 is an exploded perspective view of the reverse input cutoff clutch according to the eleventh example. FIG. 24(a) is an enlarged view of part E in FIG. 22, and FIG. 24(b) is an enlarged view of part F in FIG. 24(a). FIG. 25 is a cross-sectional view taken along line G-G in FIG. 22, with some parts omitted. FIG. 26(a) is a perspective view of a retaining member according to an eleventh example, as viewed from one axial side, and FIG. 26(b) is a perspective view of a first spacer constituting the retaining member, as viewed from the other axial side. 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. FIG. 28 is a view corresponding to FIG. 26(a) of a retaining member incorporated into a reverse input cutoff clutch according to a thirteenth example of an embodiment of the present disclosure. Fig. 29 is a view corresponding to Fig. 26(a) of a holding member incorporated into a reverse input cutoff clutch of a fourteenth example of an embodiment of the present disclosure. Fig. 30 is a view corresponding to Fig. 26(a) of a holding member incorporated into a reverse input cutoff clutch of a fifteenth example of an embodiment of the present disclosure. Fig. 31 is a view corresponding to Fig. 26(a) of a holding member incorporated into a reverse input cutoff clutch of a sixteenth example of an embodiment of the present disclosure. Fig. 32 is a view corresponding to Fig. 26(a) of a holding member incorporated into a reverse input cutoff clutch of a seventeenth example of an embodiment of the present disclosure.FIG. 33(a) is a view corresponding to portion E in FIG. 22 for a reverse input cutoff clutch according to an eighteenth example of an embodiment of the present disclosure, and FIG. 33(b) is a view corresponding to portion E in FIG. 26(a) for a retaining member incorporated into the reverse input cutoff clutch. FIG. 34 is a view corresponding to portion E in FIG. 22 for a reverse input cutoff clutch according to a nineteenth example of an embodiment of the present disclosure. FIG. 35(a) is a view corresponding to portion E in FIG. 22 for a reverse input cutoff clutch according to a twentieth example of an embodiment of the present disclosure, and FIG. 35(b) is a view corresponding to portion E in FIG. 26(a) for a retaining member incorporated into the reverse input cutoff clutch. FIG. 36(a) is a view corresponding to the H-H cross section in FIG. 22 for 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 portion I in FIG. 36(a). FIG. 37 is a perspective view of a portion of the output member and a retaining member for a reverse input cutoff clutch according to a twenty-first example of an embodiment of the present disclosure. 38(a) and 38(b) are cross-sectional views corresponding to the portion J in FIG. 25 of a reverse input cutoff clutch according to a 22nd example of an embodiment of the present disclosure. Specifically, FIG. 38(a) shows an unlocked state in which the engagement element has moved to the most radially inward position, and FIG. 38(b) shows a locked or semi-locked state in which the engagement element has moved to the most radially outward position. FIG. 39 is a cross-sectional view of a main portion for explaining inconveniences that can be prevented by the structure of the 22nd example. FIG. 40 is a cross-sectional view corresponding to the portion J in FIG. 25, with some parts omitted, of a reverse input cutoff clutch according to a 23rd example of an embodiment of the present disclosure. FIG. 41 is a cross-sectional view corresponding to the portion J in FIG. 25, with some parts omitted, of a reverse input cutoff clutch according to a 24th example of an embodiment of the present disclosure.

[0047] First Example 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 disconnection 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 disconnection clutch 1. In this example, the axial direction, radial direction, and circumferential direction of the reverse input disconnection clutch 1 coincide with the axial direction, radial direction, and circumferential direction of the input member 3, and also coincide with the axial direction, radial direction, and circumferential direction of the output member 4. One axial side is the input member 3 side (right side in FIG. 1 ), and the other axial side is the output member 4 side (left side in FIG. 1 ).

[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 engaging element 5, and a holding 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 cuts off the rotational torque that is reversely input to the output member 4 and does not transmit it to the input member 3, or that transmits only a portion of the torque 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 inner 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 shaped like 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 with a small-diameter cylindrical surface portion 10 on the other axial side by a connecting 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 on the other axial side of the small-diameter cylindrical surface portion 10.

[0055] In this example, the input element is fitted (spigot-fitted) to the output element 8 without any rattle, and the output element 8 and the input element are positioned radially, and then the output element 8 and the input element are joined to each other with a joining member such as a bolt, thereby forming 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 the 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 receive an input of rotational torque, allowing the input of rotational torque to rotate radially inside the pressed surface 7. The input-side engaging portion 14 is provided at a portion radially outwardly spaced 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 engaging portion 14 .

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

[0059] The input side engaging portion 14 protrudes toward the other axial side 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 rotation center O.

[0060] The shape of the input side engaging portion 14 is not limited as 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 configured with a plurality of engaging elements 5, the input side engaging portion 14 is also configured with a plurality of input side engaging portions 14.

[0061] In the reverse input cutoff clutch 1 of this example, the engaging elements 5 are configured with two engaging elements 5. Therefore, the input side engaging portion 14 is configured with two input side engaging portions 14 to match the number of engaging elements 5. The two input side engaging portions 14 are arranged at two radially opposite positions on the radially outer side of the end face on the other axial side of the input shaft portion 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 engaging portion 14 has an end face shape that is generally fan-shaped or trapezoidal, with a circumferential width that increases radially outward when viewed from the axial direction. The radially inner surface 16 of the input-side engaging portion 14 has a circumferential middle portion that is configured as a flat surface perpendicular to a line connecting the rotation center O and the center of the input-side engaging portion 14 when viewed from the axial direction, and both circumferential side portions that are configured as partially cylindrical convex surfaces that slope radially outward as they extend toward both circumferential sides. The radially outer surface 17 of the input-side engaging portion 14 is configured as a partially cylindrical convex surface centered on the rotation center O. The two circumferential side surfaces 18 of the input-side engaging portion 14 are configured as flat surfaces that slope away from each other as they extend radially outward.

[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 element by a radial bearing.

[0064] The output member 4 has an output-side engaging portion 19 that is arranged radially inward of the input-side engaging portion 14 on the radially inner side of the pressed surface 7, and is arranged coaxially with the pressed surface 7. In other words, 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 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 an output shaft portion 20 and a small diameter shaft portion 21 in addition to the output side engaging portion 19 .

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

[0068] The output side engaging 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] The shape of the output-side engaging portion 19 is not limited as 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 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 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 engaging pieces 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 engaging portion 19 is composed of two parallel flat surfaces 23 and two partially cylindrical convex surfaces 24. Therefore, the distance from the rotation center O of the output member 4 to the outer peripheral surface of the output-side engaging portion 19 is not constant along the circumferential direction. Each of the two convex surfaces 24 is composed of a partially cylindrical surface centered on the rotation center O of the output member 4.

[0073] The output-side engaging 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 engaging 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 has 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 alleviate 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 toward one axial direction side from the center of the end face on one axial side of the output-side engaging portion 19. In this example, the small diameter shaft portion 21 has a cylindrical shape. The small diameter shaft portion 21 has a locking groove 25 on its outer circumferential surface, at the same axial position as a locking protrusion 43 of the holding member 6 described below, with which the locking protrusion 43 is engaged. 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 on the pressed member 2 or the fixed portion. In this example, the output member 4 is rotatably supported radially inside the output element 8 of the pressed member 2 by a radial rolling bearing 26. The outer ring 27 of the radial rolling bearing 26 is fitted securely into the small-diameter cylindrical surface portion 10 of the output element 8 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 one axial end of the small-diameter cylindrical surface portion 10. The inner ring 29 of the radial rolling bearing 26 is fitted securely onto the end of one axial side of the output shaft portion 20 and is axially sandwiched between a side surface on the other axial side of the output flange portion 22 and a segmented annular retaining ring 28b engaged with the outer peripheral surface of the axially middle portion of the output shaft portion 20.

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

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

[0079] The engaging element 5 has a pressing surface 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 a direction away from the pressed surface 7 in the first direction based on the input side engaging portion 14 engaging 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, whereas 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, and presses the pressing surface 32 against the pressed surface 7, causing frictional engagement of the pressing surface 32 with the pressed surface 7.

[0081] As long as the engaging element 5 has such a configuration, it may be configured with one engaging element 5 or with 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 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 of approach or distance of the pressing surface 32 relative to the pressed surface 7, and corresponds to the direction indicated by arrow A in Fig. 5. The width direction with respect to the engaging element 5 is the direction perpendicular to both the direction of approach or distance of the pressing surface 32 relative to the pressed surface 7 and the axial direction of the pressed surface 7, and corresponds to the direction indicated by 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 that faces 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] When viewed from the axial direction, the portion of the radially outer surface of the engaging element 5 that is circumferentially offset from the two pressing surfaces 32 is located radially inward of an imaginary circle that is centered on the rotation center O of the input member 3 and that is tangent to the two pressing surfaces 32. 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] The pressing surface 32 preferably has a surface property that has a higher coefficient of friction with the pressed surface 7 than the other parts of the engaging element 5. The pressing surface 32 may be formed integrally with the other parts of the engaging element 5, or may be formed by 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 of the engaging 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 an opening shape that is approximately arched when viewed from the axial direction, and is configured as a through hole that passes through the radial middle portion of the engaging element 5 in the axial direction at the center position in the width direction.

[0089] The input-side engaged portion 33 has a size that allows the input-side engaging portion 14 to be loosely inserted therein. 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 both the width direction and the radial direction of the engaging element 5. Therefore, the input-side engaging portion 14 is capable of displacement relative to the input-side engaged portion 33 in the rotational direction of the input member 3, and the input-side engaged portion 33 is capable of displacement 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 configured as 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 engaging 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 that is perpendicular to the radial direction of the engaging element 5, and the flat surface portion 36 has two protrusions 37 that protrude 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 located between the two protrusions 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 protrusions 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 arranged radially inward of the pressed member 2 so as to be movable in a first direction. Furthermore, the two input-side engaging portions 14 of the input member 3 arranged 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 arranged on the other axial side is axially inserted between the output-side engaged portions 34 of the two engaging elements 5. In other words, the two engaging elements 5 are arranged so that the output-side engaging portion 19 is sandwiched 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 areas between the pressed surface 7 and the pressing surface 32 and between the tip surfaces 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 restricting 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 formed in a flat plate shape, and has an end face shape that is generally oval or generally rectangular 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 that is 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 retaining member 6 has a locking protrusion 43 protruding from the outer circumferential surface of the output-side engaging portion 19 or the surface facing the outer circumferential surface of the small-diameter shaft portion 21. The locking protrusion 43 can protrude, for example, from the surface of at least one of the first spacer portion 38, the second spacer portion 39, and the connecting portion 40 facing the outer circumferential surface of the output-side engaging portion 19 or the outer circumferential surface of the small-diameter shaft portion 21. 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 into the locking groove 25 of the output member 4. In this example, the locking protrusion 43 protrudes radially inward from the other axial side portion of the inner circumferential surface of the first through hole 41 around the entire periphery, except for the portion where the discontinuous portion 45 is provided.

[0100] In this example, the side surface on the other axial side of the locking protrusion 43 has an inclined surface portion 44, at least in the radially inner portion, which is the tip side portion in the protruding direction of the locking protrusion 43, that is inclined in a direction toward one axial side as it moves radially inward, which is the tip side in the protruding direction. 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 side of the locking protrusion can be configured with an inclined surface portion that inclined in a direction toward one axial side as it moves radially inward. In this example, the side surface on one axial side of the locking protrusion 43 is configured with a plane that is 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 provided to facilitate elastic expansion and contraction of the inner diameters of the first through-hole 41 and the locking protrusion 43, and is open to the inner circumferential surface of the first through-hole 41, the outer circumferential surface of the first spacer portion 38, and both axially opposite side surfaces. Therefore, the inner circumferential 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 is present. 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 first spacer portion 38 in the longitudinal direction (left-right direction in FIG. 4 ).

[0102] In this example, the second spacer portion 39 has a second through-hole 46 through which the output-side engaging portion 19 is inserted. The second through-hole 46 axially penetrates the center of the second spacer portion 39, has a generally oval or rectangular opening shape when viewed from the axial direction, and is large enough to allow the output-side engaging portion 19 to be inserted without rattle. In this example, the second spacer portion 39 has a chamfered portion 65 on the opening edge 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 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 connecting portion 40 is not particularly limited as long as it connects the first spacer portion 38 and the second spacer portion 39 and is configured so as not to hinder the movement of other components when the reverse input cutoff clutch 1 is in use. In this example, each connecting portion 40 has a rectangular column shape extending in the axial direction of the pressed surface 7. One axial end of each connecting portion 40 is integrally connected to a side surface on the other axial side of the center portion in the short direction (first direction) of each end on both sides of the longitudinal direction (second direction) of the first spacer portion 38, and the other axial end of each connecting portion 40 is integrally connected to a side surface on one axial side of the center portion in the short direction (first direction) of each end on both sides of the longitudinal direction (second direction) of the second spacer portion 39. That is, in this example, the entire retaining member 6 is configured as a single unit.

[0105] The holding member 6 is made of, but is not limited to, 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-side ends 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 , when rotational torque is input to the input member 3, the output-side engaging portion 19 of the output member 4 is clamped from both radial sides (first direction) by the output-side engaged portions 34 of the two engaging elements 5 in an unlocked state, and the width dimension of each connecting portion 40 in the radial direction (first direction) is regulated 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 width dimension of each connecting portion 40 in the radial direction (first direction) is smaller than the distance between the two flat surfaces 23 provided on the outer peripheral 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 restricted 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 on the other axial direction of the second spacer portion 39 abuts against the end face 63, thereby restricting movement of the holding member 6 in 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 at the time of contact. Also, when the bottom surface of the engagement recess 42 abuts against the end face 66, thereby restricting movement of the holding member 6 in the other axial direction relative to the output member 4, an axial gap is generated between the side surface on the other axial direction of the second spacer portion 39 and the end face 63 at the same time. Alternatively, when the side surface on the other axial direction of the second spacer portion 39 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, movement of the holding member 6 in 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 of the locking protrusion 43 on one axial side abutting against the side surface 67 of the inner surface of the locking groove 25 facing the other axial side.

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

[0113] In this example, the biasing member 47 is arranged 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 sandwiched 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 biasing member 47 is configured by two biasing members 47 that are respectively arranged between the radially inner surfaces of the two engagement pieces 5 and the output side engagement portion 19 .

[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 as a leaf spring having two arms 48 and two connecting portions 49. Each arm 48 has a notch that opens at its tip and has a generally U-shaped planar shape when viewed from the plate thickness direction (first direction). Each connecting portion 49 has a strip 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 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 side of the first spacer portion 38 that constitutes the retaining member 6 and the side surface on one axial side of the second spacer portion 39.

[0117] The biasing member 47 is attached to the engaging member 5 in a state where 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 portions of the urging 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 in 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 element 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 elements 5 relative to the output member 4.

[0121] 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 side of the first spacer portion 38 and the side surface on one axial side of the second spacer portion 39 that constitute the holding member 6. Therefore, the engaging element 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 configured to elastically abut against the two connecting portions 49 that constitute the biasing member 47. This suppresses rattle between the output-side engaging portion 19 and the output-side engaged portion 34.

[0123] <Explanation of Operation of Reverse Input Cutoff Clutch> The operation of the reverse input cutoff clutch 1 of this example will be described with reference to Figures 6 and 7. Figures 6 and 7 omit the illustration of the holding member 6 and the biasing member 47, and exaggerate the radial gaps between the input member 3 and the output member 4 and the two engaging elements 5.

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

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

[0126] When the input member 3 rotates further from this state, the radially inner surface 16 of the input-side engaging portion 14 presses the radially 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 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 directions approaching each other, the radially inner surfaces of the two engaging elements 5 approach each other, and the output-side engaged portion 19 of the output member 4 is sandwiched between 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 is 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 rattle. 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, with the remainder being blocked.

[0129] 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 the connection (corner) 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 input inversely to the output member 4 is completely blocked and not transmitted to the input member 3, or only a portion of the rotational torque input 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 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 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 input inversely to the output member 4 to the input member 3 and block the remainder, the engaging element 5 is clamped between the output side engaging portion 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 example, the size of the gap between each component is adjusted to enable the above operation. In particular, when the pressing surface 32 of the engaging element 5 is in contact with 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 engaging portion 14 from blocking the radially outward movement of the engaging element 5 when a rotational torque is input in reverse to the output member 4, and even after the pressing surface 32 comes into contact with the pressed surface 7, the surface pressure acting on the contact point 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, ensuring that the output member 4 is locked or semi-locked appropriately.

[0136] In the reverse input cutoff clutch 1 of this example, the biasing member 47 elastically biases the engaging element 5 in a direction approaching the pressed surface 7 in the first direction. This allows the two pressing surfaces 32 of the engaging element 5 to be kept in contact with the pressed surface 7 except when rotational torque is input to the input member 3. Therefore, when rotational torque is reversely input to the output member 4, the surface pressure at the contact points between the two pressing surfaces 32 of the engaging 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 example, one holding member 6 is used as a restraining member for restraining 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 when two independent spacers installed on both axial sides of the engagement element 5 are used as such restraining members. This makes it possible to reduce the cost of managing parts and the number of steps required to assemble the reverse input cutoff clutch 1.

[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. Therefore, compared to a structure in which a segmented annular retaining ring is engaged in 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 member is prevented from coming off in one axial direction from the output member by the retaining ring, the retaining ring is not required. Therefore, from this perspective as well, the number of parts can be reduced.

[0139] <Method of assembling reverse input cut-off clutch> The method of assembling the reverse input cut-off clutch of this example includes the steps of combining the output member 4, the two engaging elements 5, the retaining member 6, and the two biasing members 47, and using an assembly jig (not shown) that engages the input side engaged portions 33 of the two engaging elements 5, displacing the two engaging elements 5 in a direction that brings them closer to each other in the radial direction against the elastic biasing forces of the respective biasing members 47, and then inserting the two engaging elements 5 from the axial direction radially inside 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 locked onto the outer peripheral surface of the axially intermediate portion of the output shaft portion 20. The biasing members 47 are attached to the radially inner ends of the two engaging elements 5, respectively.

[0142] 9(a) and 9(b), the two engaging elements 5 are arranged so that the two connecting portions 40 constituting the holding member 6 are sandwiched 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) and 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.

[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 that constitute the holding member 6, the locking protrusion 43 elastically expands in diameter and rides up from the end of 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 elastically restores its original shape to reduce its diameter and be locked in the locking groove 25.

[0145] In this example, an inclined surface 44 that is inclined toward one axial side as it extends radially inward is provided on the radially inner portion of the side surface on the other axial side of the locking protrusion 43. Therefore, when the locking protrusion 43 rides up from the end 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 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 rides up from the end on one axial side of the small diameter shaft portion 21 onto the outer circumferential surface of the small diameter shaft portion 21 more easily.

[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 viewpoint, when the locking protrusion 43 rides up onto the outer peripheral surface of the small diameter shaft portion 21 from one axial end of the small diameter shaft portion 21, the locking protrusion 43 is more likely to elastically expand in diameter.

[0147] In this example, the side surface on one axial direction of the locking protrusion 43 is configured as a plane perpendicular to the axial direction of the pressed surface 7. Therefore, even if a force toward one axial direction acts on the holding member 6 relative to the output member 4 when the locking protrusion 43 is locked in the locking groove 25, the engagement between the side surface on one axial direction of the locking protrusion 43 and the side surface on one axial direction that constitutes 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 assembly jig, which has been engaged with the input-side engaged portions 33 of the two engaging elements 5, displaces the two engaging elements 5 in directions that bring them closer to each other in the radial direction against the elastic biasing forces of the biasing members 47. This makes it possible to facilitate the assembly work.

[0149] After the other axial end face of the outer ring 27 of the radial rolling bearing 26 abuts against the side face of one axial side of the inward flange portion 12, the assembly jig is retracted, 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 surfaces 7. Then, a retaining ring 28a is engaged with the end of 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 the steps for assembling the output side assembly 51 can be changed as appropriate as long as no contradiction occurs.

[0151] Furthermore, the input member 3 is rotatably supported inside the input element by the radial bearing, thereby obtaining an input 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 so that they approach each other.

[0153] As a result, the input element is fitted to 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 together with joining members such as bolts, thereby assembling the reverse input cutoff clutch 1.

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

[0155] 10(e) of the comparative example, when assembling the preliminary assembly 50a, the other axial end of the output-side engaging portion 19 is inserted into the through-hole 55 of the first spacer 52, as shown in FIGS. 10(a) and 10(b). 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 engaging elements 5 are arranged so that the axial middle portion of the output side engaging portion 19 is sandwiched from the radial outside by the biasing members 47 attached to each engaging element 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) and 10(e), the retaining ring 54 is engaged with the engaging groove 25 of the output member 4, thereby obtaining a preliminary assembly 50a.

[0159] As described above, when assembling the preliminary assembly 50a of the comparative example, three steps are required 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)), only the step of assembling the retaining member 6 needs to be performed as the step of assembling the member for restricting the axial movement of the two engaging elements 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, and therefore the assembly workability can be improved.

[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, these materials can be metals such as iron alloys, copper alloys, and aluminum alloys, as well as synthetic resins containing reinforcing fibers as needed. The pressed member, input member, output member, and engaging element can be made of the same material or different materials. The holding member can also be made of a material different from that used in this example, such as a metal such as an iron alloy, copper alloy, or aluminum alloy.

[0162] When 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 contact portions of the pressed member, input member, output member, and engaging element. Alternatively, at least one of the pressed member, input member, output member, and engaging element can be made of oil-impregnated metal.

[0163] Second Example 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 in the first example.

[0164] In this example, the outer peripheral surface of small diameter shaft portion 21a has a small diameter portion 56 that forms one axial side portion, a large diameter portion 57 that forms the other axial side portion, and a stepped surface 58 that faces one axial side and connects 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 one axial end to the axial middle, and is composed of a cylindrical surface whose outer diameter does not change in the axial direction except for a chamfered portion present 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 other axial end, and is composed of a cylindrical surface whose outer diameter does not change in the axial direction except for a portion where the locking groove 25 is present. In this example, the stepped surface 58 is composed of a conical surface that slopes radially outward toward the other axial side. In this example, the locking groove 25 is provided at the other axial end of the large diameter portion 57.

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

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

[0168] This shortens the distance over which the locking projections 43 are moved axially while elastically expanding during assembly, thereby improving assembly workability and effectively preventing damage to the locking projections 43. The remaining configurations and effects of the second example are the same as those of the first example.

[0169] 12(a) and 12(b) , a third example of the embodiment of the present disclosure will be described. In this example, the shape of the first spacer portion 38a constituting the holding member 6a is different from that in 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 portion 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 axially move the outer circumferential surface of the small diameter shaft portion 21 while elastically expanding the diameter of the locking protrusion 43 when assembling the retaining member 6a to the output member. Therefore, the assembly workability of the reverse input cutoff clutch can be improved. The configuration and effects of other parts of the third example are the same as those of the first example.

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

[0173] In this example, the first spacer portion 38b does not have any discontinuous portions anywhere in the circumferential direction and is continuous around the entire circumference. Instead, in this example, the locking protrusions 43a are provided in multiple circumferentially spaced locations 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, making it easier for each locking protrusion 43a to elastically deform 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 retaining member 6b to the output member, it is easy to move the outer peripheral 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 43a. This improves the ease of assembly of the reverse input cutoff clutch. The remaining configurations and effects of the fourth example are the same as those of the first example.

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

[0176] In this example, the first spacer portion 38c has the shape features of both Examples 3 and 4. That is, the first spacer portion 38c has discontinuous portions 45 at two circumferential locations, that is, at two locations located on both sides of the center of the longitudinal direction of the first spacer portion 38c in the short direction, and the first through-hole 41 has locking protrusions 43a at multiple locations spaced apart in the circumferential direction 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 move the outer peripheral 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 43, thereby further improving the ease of assembly of the reverse input cutoff clutch. The configuration and effects of other parts of the fifth example are the same as those of the first example.

[0178] 15(a) and 15(b) , a sixth example of the embodiment of the present disclosure will be described. 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 engaging 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 so that the output-side engaging portion 19 can be inserted without rattle.

[0180] In this example, with the holding member 6d assembled to the output member 4b, the 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 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 holding member 6d relative to the output member 4b toward one axial side is restricted by the side surface of the first spacer portion 38d on one axial side abutting against or closely facing the input member-side restricting portion 59. In contrast, movement of the holding member 6d relative to the output member 4b toward the other axial side is restricted by the side surface of the second spacer portion 39 on the other axial side abutting against or closely facing the end face 63 of the output shaft portion 20 on one axial side.

[0184] In this example, with regard to the axial position regulation structure of the holding member 6d relative to the output member 4b, the holding member 6d does not have an engaging protrusion and the output member 4b does not have an engaging groove, so the structures of the holding 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 have a locking protrusion as in this example, the axial halves of the retaining member can be shaped symmetrically to each other to prevent incorrect assembly of the retaining member during assembly. In other words, if the axial halves of the retaining member are shaped symmetrically to each other, 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 in order to prevent 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] The specific manner in which the axially opposite halves of the retaining member are 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 enough to be easily recognizable by an assembly worker or robot. 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 also be provided on the opening edge of the through-hole only in the second spacer portion 39.

[0188] When implementing the present disclosure, regardless of whether or not a locking protrusion is present, the axial thicknesses of the first spacer portion and the second spacer portion can be set arbitrarily as long as the strength and functionality required of the retaining member are ensured. The smaller the axial thicknesses of the first spacer portion and the second spacer portion, the more they contribute to shortening the axial dimension of the reverse input disconnection clutch. For example, in the structure of this example, the axial thickness of the first spacer portion 38d is greater than the axial thickness of the second spacer portion 39. However, if the axial thickness of the first spacer portion 38d is set equal to or less than the axial thickness of the second spacer portion 39, this contributes to shortening the axial dimension of the reverse input disconnection clutch accordingly. The remaining configurations and effects of the sixth example are the same as those of the first example.

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

[0190] In this example, the structure of the retaining member 6e differs from 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 retaining member 6d of the sixth example. In this example, when the retaining member 6e is 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 rattle.

[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 side of the radially outer portion of the retaining ring 60, thereby restricting movement of the retaining member 6e to one axial side relative to the output member 4. The manner in which movement of the retaining member 6e to the other axial 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 because the retaining member 6e does not have a locking protrusion with respect to the structure for restricting the axial position of the retaining member 6e relative to the output member 4. During 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 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 and employing a structure in which a snap ring restricts movement of the retaining member to one axial direction as in this example, the same retaining member as in Example 6 can be used. However, as in this example, if the axial thickness of the first spacer portion 38e constituting the retaining member 6e is made smaller than in Example 6, 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 a retaining ring is used to restrict movement of the retaining member to one side in the axial direction, as in this example, from the perspective of preventing or suppressing incorrect 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 to each other, or for 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] 17(a) and 17(b) , an eighth example of the embodiment of the present disclosure will be described. In this example, the structure for restricting the axial position of the holding member 6f with respect to the output member 4c is different from that of the seventh example.

[0197] In this example, the structure of the retaining member 6f differs from that of the seventh example only in that the retaining member 6f has locking protrusions 43b at two circumferential locations on the inner circumferential 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 other axial end of the inner circumferential surface of the first through-hole 41a, extending 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 its outer circumferential surface, and the output-side engaging portion 19a has locking grooves 25a with which the respective locking protrusions 43b are locked at positions that align with the two locking protrusions 43b on the outer circumferential surface, specifically, at one axial end of the two flat surfaces 23. The two locking protrusions 43b are locked to the two locking protrusions 43b.

[0199] In this example, movement of the holding member 6f toward 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 method for restricting movement of the holding member 6f toward the other axial side relative to the output member 4c 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] 18(a), 18(b), and 18(c), a ninth example of the embodiment of the present disclosure will be described. 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 components.

[0203] The first spacer portion 38g and the second spacer portion 39a are each formed in a flat plate shape, and have an end face shape that is generally oval or generally rectangular 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 connecting portions 40a are each configured as a stepped column having small diameter portions 62 at both axial ends.

[0207] The retaining member 6g is assembled by press-fitting 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 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.

[0208] In this example, the components 38g, 39a, and 40a that make up the holding member 6g each have a simple shape, which makes it possible to reduce the manufacturing costs of these components 38g, 39a, and 40a.

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

[0210] 19 to 21(b), a tenth example of the embodiment of the present disclosure will be described. In this example, the structures of the biasing member 47a and the holding member 6h are different from those in 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 engaging elements 5. Each of the two urging members 47a is composed of a compression coil spring 69. The compression coil spring 69 constituting each urging member 47a is held by inserting the protrusions 37 provided on the two engaging elements 5 into both axial sides of the spring. Each of the two compression coil springs 69 is elastically compressed in the first direction between the two engaging elements 5.

[0212] In this example, in the holding member 6h, the distance between the side surface on the other axial side of the first spacer portion 38h and the side surface on one axial 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 the intervention of 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 greater than in Example 1, 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 in this example, for example, the axial thickness can be made the same as in Example 1. Doing so can 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 when the reverse input disconnect clutch is in an assembled state. 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 this application, the amount of change is negligibly small.

[0215] In this example, when the reverse input disconnection clutch is assembled, the outer diameter Dc of each compression coil spring 69 is greater than the axial thickness T5 of the engaging element 5 (Dc > T5). However, when implementing the present disclosure, when the reverse input disconnection clutch 1a is assembled, the outer diameter Dc of each compression coil spring 69 can also be set to be equal to or less than the axial thickness T5 of the engaging element 5 (Dc ≦ T5). Employing this dimensional relationship (Dc ≦ T5) prevents the extension end of each compression coil spring 69 from biasedly contacting the flat surface portion 36 of the engaging element 5, making it easier to prevent the central axis of each compression coil spring 69 from tilting 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 elements 5, the holding member 6h, and the two biasing members 47a, and using an assembly jig (not shown) that engages the input-side engaged portions 33 of the two engaging elements 5, displacing the two engaging elements 5 in a direction toward each other in the radial direction against the elastic biasing forces of the two biasing members 47a, and then inserting the two engaging elements 5 axially 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 configuration and effects of other parts of the tenth example are the same as those of the first example.

[0217] 22 to 26(b), an eleventh example of the embodiment of the present disclosure will be described. In this example, the structure of the 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 arranged on both sides of the first spacer portion 38i and the second spacer portion 39c in the second direction, and is composed of two connection portions 40b, 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] The shape of each connecting portion 40b is not particularly limited 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 hinder 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 its thickness direction in the first direction, and has a substantially rectangular end face shape when viewed from the first direction.

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

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

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

[0223] In addition, when implementing the present disclosure and the engaging element is configured as a single engaging element, each of the retaining holes provided at the two connection portions of the retaining member can be configured as 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, when the reverse input cutoff clutch 1a is in an assembled state, 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 play, 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 FIGS. 19 and 20 ) on its radially inner surface. In this example, the entire radially inner surface of the engaging element 5 is formed by 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 central portion in the width direction of the flat surface portion 36. In the structure of this example, there is no need to provide the engaging element 5 with a portion for holding the two compression coil springs 69, so the shape of the engaging element 5 can be simplified and the manufacturing cost of the engaging element 5 can be reduced.

[0226] The assembly method for 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 retaining member 6i, and the two compression coil springs 69, and then, using an assembly jig (not shown) that engages the input-side engaged portions 33 of the two engaging elements 5, displacing the two engaging elements 5 radially toward each other against the elastic biasing forces of the two compression coil springs 69, and then inserting the two engaging elements 5 axially into the radially inner side of the pressed surface 7. This facilitates the assembly of the reverse input cutoff clutch 1a of this example. The remaining configurations and effects of the eleventh example are the same as those of the tenth example.

[0227] [Twelfth Example] 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 reasons as in Example 2. The configuration and effects of other parts of Example 12 are the same as those of Example 11.

[0230] [Thirteenth Example] 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, similar 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 reasons as in Example 3. The configuration and effects of other parts of Example 13 are the same as those of Example 11.

[0233] [14th Example] A 14th 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 differs from that of the 11th example.

[0234] In this example, similar to the fourth example, the first spacer portion 38k is continuous around the entire circumference without any discontinuities anywhere in the circumferential direction of the first through-hole 41. Instead, in this example, the first spacer portion 38k has locking protrusions 43a provided at multiple locations spaced apart in the circumferential direction on the inner circumferential surface of the first through-hole 41. 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.

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

[0236] Fifteenth Example 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 differs from that of the eleventh example.

[0237] In this example, as in the fifth example, the first spacer portion 38l has discontinuous portions 45 at two circumferential locations, located on both sides of the short side (first direction) of the center of the longitudinal direction (second direction) 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 other parts of Example 15 are the same as those of Example 11.

[0239] Sixteenth Example A sixteenth example of the embodiment of the present disclosure will be described with reference to Fig. 31. In this example, the shape of the two connecting portions 40c that constitute the 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 is open 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 of the connection portion 40c that is closer to the center of the retaining member 6d in the second direction.

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

[0242] In the structure of this example, when the first through-hole 41 elastically expands and contracts, two axially opposing portions of each connection portion 40c sandwiching the discontinuous portion 70 are relatively displaced, thereby reducing the expansion and contraction rigidity of the first through-hole 41. Therefore, when assembling the retaining member 6d to the output member 4 (see FIGS. 24(a) and 24(b)), the work of elastically expanding the diameter of the inscribed circle of the multiple locking protrusions 43a while moving the outer circumferential surface of the small diameter shaft portion 21 in the axial direction is made easier, further improving the ease of assembly of the reverse input cutoff clutch. The remaining configurations and effects of the sixteenth example are the same as those of the fifteenth example.

[0243] 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 connecting portion 40d, the discontinuous portion 70 is provided in the axial center of the end portion farthest 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 the same as those of the fifteenth example.

[0245] An eighteenth 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 6o with respect to the output member 4b is different from that of the eleventh example.

[0246] In this example, the position restriction structure is similar to that of the sixth example. That is, in this example, the retaining member 6o 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 of the retaining member 6o has a first through-hole 41a through which the output-side engaging portion 19 is inserted without rattle. In this example, movement of the retaining member 6o toward one axial direction relative to the output member 4b is restricted by the side surface of the first spacer portion 38m on one axial side abutting or closely facing the input-member-side restricting portion 59 of the input member 3. In contrast, movement of the retaining member 6o toward the other axial side relative to the output member 4b is restricted by the side surface of the second spacer portion 39c on the other axial side 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 holding member 6o does not have a locking protrusion and the output member 4b does not have a locking groove with respect to the position restriction structure, so that the structures of the holding member 6o and the output member 4b can be simplified. The configurations and effects of other parts of the eighteenth example are the same as those of the eleventh example.

[0248] [19th Example] A 19th 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 relative to the output member 4 differs from that of the 18th example.

[0249] In this example, the same structure as in the seventh example is adopted as the position restriction structure. That is, in this example, the structure of the retaining member 6p differs from that of the retaining member 6o 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 segmented annular retaining ring 60. The radially inner portion of the retaining ring 60 is engaged with a locking groove 25 provided on the other axial end of the outer peripheral surface of the small diameter shaft portion 21 of the output member 4. In this example, the first spacer portion 38n of the retaining member 6p engages with the other axial side of the radially outer portion of the retaining ring 60, thereby restricting movement of the retaining member 6p to one axial side relative to the output member 4. The manner in which movement of the retaining member 6p to the other axial side relative to the output member 4 is restricted is the same as in the eighteenth example.

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

[0251] 35(a) and 35(b) , a twentieth example of the embodiment of the present disclosure will be described. In this example, the structure for restricting the axial position of the holding member 6q with respect to the output member 4c is different from that of the nineteenth example.

[0252] In this example, the position restriction structure is similar to that of the eighth example. That is, in this example, the structure of the retaining member 6q differs from that of the nineteenth example only in that the retaining member 6q has locking protrusions 43b at two circumferential locations on the inner circumferential surface of the first through-hole 41a of the first spacer portion 38o. In this example, the locking protrusions 43b are provided on both sides of the axial portion (axial middle portion in the illustrated example) of the inner circumferential surface of the first through-hole 41a in the lateral direction (first direction) of the first spacer portion 38o, extending in the longitudinal direction (second direction) of the first spacer portion 38o. In this example, an inclined surface 44a 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 43b.

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

[0254] In this example, movement of the holding member 6q toward 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 method for restricting movement of the holding member 6q toward the other axial side relative to the output member 4c 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] 21st Example A 21st 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 18th example.

[0256] This example differs from Example 18 in that the locking protrusion 43c that locks into 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 axially 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 entire side surface on the other axial side of the locking protrusion 43c is formed by an inclined surface portion 44b that functions as a guide surface during assembly. In addition, the side surface on one axial side of the locking protrusion 43c is formed by a flat surface that is 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 of 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, movement of the holding member 6r relative to the output member 4d toward one axial side 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 movement of the holding member 6r relative to the output member 4d toward the other axial side 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] 22nd Example A 22nd example of the embodiment of the present disclosure will be described with reference to FIGS.

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

[0263] Although not limited to this, in this example, the pressing piece 71 has a stepped cylindrical shape made up 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 made up 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 end of the compression coil spring 69 in the extension direction with its small diameter portion 73 inserted into the end of the compression coil spring 69 in the extension direction and its stepped surface 75 abutting against the edge of the compression coil spring 69 in the extension direction, and its tip surface 74 is in surface contact with the flat surface 36 of the engaging member 5. In this state, the compression coil spring 69 elastically presses the stepped surface 75 of the pressing piece 71, thereby elastically pressing against the flat surface 36 of the engaging 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 retaining hole 68 of the retaining member 6 so as to be slidable in the extension direction (first direction) of the retaining 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 retaining hole 68 so as to be slidable in the extension direction of the retaining hole 68 without any rattle in the radial direction of the retaining 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 retaining hole 68 is always maintained, and specifically, this state is maintained not only in the unlocked state in which the engaging pieces 5 are moved to the innermost position in the radial direction as shown in Figures 6 and 38(a) but also in the locked or semi-locked state in which the engaging pieces 5 are moved to the outermost position in the radial direction as shown in Figures 7 and 38(b).

[0267] In this example, each compression coil spring 69 elastically presses 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 of 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 the ends on both sides of the extension direction of the compression coil spring 69 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 by the 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 pressing 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 portions of the ends of the compression coil spring 69 on both sides in the extension direction that protrude from the retaining hole 68 to elastically deform radially outward (to the left in FIG. 39 ) around 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 periphery of the retaining hole 68 (portion P in FIG. 39 ), which may result in an inconvenience such that the compression coil spring 69 cannot be smoothly compressed.

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

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

[0272] In the reverse input disconnecting clutch of this example, the inner circumferential surface of each retaining hole 68a constituting the retaining member 6s is provided at both opening end portions in the extension direction with guide surface portions 76 whose inner diameter increases toward the opening side. In this example, the guide surface portions 76 have a convex arc cross-sectional shape. However, when implementing the present disclosure, the cross-sectional shape of the guide surface portions may also be a straight shape as shown by the two-dot chain line α in Figure 40.

[0273] In this example, the inner peripheral surface of the retaining hole 68a is provided with guide surface portions 76 at both opening end portions in the extension direction, each of which has an inner diameter that increases toward the opening. This facilitates insertion of the compression coil spring 69 into the retaining hole 68a during assembly. Furthermore, due to the low bending rigidity of the compression coil spring 69, even if the ends of the compression coil spring 69 elastically deform radially outward (to the left in FIG. 40 ) about the rotation center axis due to centrifugal force generated during rotation of the reverse input disconnect clutch, these portions are unlikely to get caught on the opening periphery of the retaining hole 68a (area P in FIG. 40 ). This allows for an appropriate spring force to be applied to the engaging element. The remaining configurations, functions, and effects of the twenty-third example are similar to those of the eleventh example.

[0274] 24th Example 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 outer diameter of each compression coil spring 69a becomes smaller from the middle portion toward both ends in the extension direction of the compression coil spring 69a.

[0276] This makes it easy to insert the compression coil spring 69a into the retaining hole 68 of the retaining member 6i during assembly. Furthermore, due to the low bending rigidity of the compression coil spring 69a, even if both ends of the compression coil spring 69a in the extension direction are elastically deformed radially outward (to the left in FIG. 41 ) about the central axis of rotation due to centrifugal force generated when the reverse input disconnect clutch rotates, these ends are less likely to get caught on the opening periphery of the retaining hole 68a (area P in FIG. 41 ). This allows an appropriate spring force to be applied to the engaging element. The remaining configurations, functions, and effects of the twenty-fourth example are similar to those of the eleventh example.

[0277] The reverse input cutoff clutch of the present disclosure can be implemented by appropriately combining the structures of the first to twenty-fourth examples within a range that does not cause contradictions.

[0278] REFERENCE SIGNS LIST 1, 1a Reverse input cutoff clutch 2 Pressed member 3 Input member 4, 4a, 4b, 4c, 4d Output member 5, 5a, 5b Engagement elements 6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j, 6k, 6l, 6m, 6n, 6o, 6p, 6q, 6r, 6s Holding member 7 Pressed surface 8 Output side element 9 Large diameter cylindrical surface portion 10 Small diameter cylindrical surface portion 11 Connection surface portion 12 Inward flange portion 13 Threaded hole 14 Input side engaging portion 15 Input shaft portion 16 Radially inner surface 17 Radially outer surface 18 Circumferential side surface 19 Output side engaging portion 20 Output shaft portion 21, 21a, 21b Small diameter shaft portion 22 Output flange portion 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 ring 30 Rolling element 31 Slide bearing 32 Pressing surface 33, 33a, 33b Input side engaged portion 34 Output side engaged portion 35 Radial inner surface 36 Flat surface portion 37 Convex portion 38, 38a, 38b, 38c, 38d, 38e, 38f, 38g, 38h, 38i, 38j, 38k, 38l, 38m, 38n, 38o First spacer portion 39, 39a, 39b, 39c Second spacer portion 40, 40a, 40b, 40c, 40d, 40e Connecting portion 41, 41a First through hole 42 Engaging recess 43, 43a, 43b, 43c Locking protrusion 44, 44a, 44b Inclined surface portion 45 Discontinuous portion 46 Second through-hole 47, 47a Urging member 48 Arm portion 49 Connecting portion 50, 50a Preliminary assembly 51 Output side assembly 52 First spacer 53 Second spacer 54 Retaining ring 55 Through-hole 56 Small diameter portion 57 Large diameter portion 58 Step surface 59 Input member side restricting portion 60 Retaining ring 61a, 61b Connection hole 62 Small diameter portion 63 End face 64 Corner R portion 65 Chamfered portion 66 End face 67, 67a Side surface 68, 68a Retaining hole 69, 69a Compression coil spring 70 Discontinuous portion 71 Pressing piece 72 Large diameter portion 73 Small diameter portion 74 Tip surface 75 Step surface 76 Guide surface portion

Claims

1. A pressed member having a pressed surface on its inner circumferential surface; an input member having an input side engaging portion arranged radially inward of the pressed surface and arranged coaxially with the pressed surface; an output member having an output side engaging portion arranged radially inward of the input side engaging portion and arranged coaxially with the pressed surface; an engaging element having a pressing surface facing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and arranged to be movable in a first direction which is a direction in which the pressing surface moves toward or away from the pressed surface; and 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 with the engaging element arranged 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. 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 engager moves in the first direction away from the pressed surface, and engages the output side engaged portion with the output side engaging portion, thereby transmitting the rotational torque input to the input member to the output member. Conversely, when a rotational torque is input in reverse to the output member, the output side engaging portion engages with the output side engaged portion, so that the pressing surface is pressed against the pressed surface, frictionally engaging the pressing surface with the pressed surface. A reverse input cut-off clutch.

2. A reverse input cut-off clutch as described in claim 1, wherein the output member has a small diameter shaft portion protruding from the center of one axial end face of the output side engaging portion towards said one axial side, the first spacer portion has a first through hole through which the output side engaging portion and / or the small diameter shaft portion is inserted, and the second spacer portion has a second through hole through which the output side engaging portion is inserted.

3. A reverse input cut-off clutch as set forth in claim 2, wherein the retaining member has a locking protrusion protruding from the outer circumferential surface of the output side engaging portion or a surface facing the outer circumferential surface of the small diameter shaft portion, and the output side engaging portion or the small diameter shaft portion has a locking groove with which the locking protrusion engages, at the same axial position on its outer circumferential surface as the locking protrusion.

4. A reverse input cut-off clutch as set forth in claim 3, wherein 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, that is inclined in a direction toward the one axial side as it approaches the tip end in the protruding direction.

5. A reverse input cutoff clutch as set forth in claim 4, wherein said one axial side surface of said locking projection is formed by a flat surface perpendicular to the axial direction of said pressed surface.

6. A reverse input cutoff clutch as set forth in claim 3, wherein said locking projections are provided at a plurality of locations spaced apart in the circumferential direction.

7. A reverse input cutoff clutch as set forth in any one of claims 3 to 6, wherein the locking projection protrudes from the inner circumferential surface of the first through hole.

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

9. A reverse input cut-off clutch as set forth in claim 7, wherein the outer peripheral 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 stepped surface facing one axial side connecting the small diameter portion and the large diameter portion, the outer diameter of the small diameter portion being equal to or smaller than the diameter of the inscribed circle of the locking protrusion, the outer diameter of the large diameter portion being greater than the diameter of the inscribed circle of the locking protrusion, and the locking groove being provided in the large diameter portion.

10. A reverse input cut-off clutch as described in claim 2, wherein the input member has an input member side regulating portion that regulates the movement of the retaining member to one side in the axial direction relative to the output member based on engagement with the first spacer portion.

11. A reverse input cut-off clutch as described in claim 2, further comprising a retaining ring whose radially inner portion is engaged with a portion of the outer circumferential surface of the small diameter shaft portion that is located on one axial side of the first spacer portion, and the first spacer portion engages with a side surface on the other axial side of the radially outer portion of the retaining ring, thereby restricting movement of the retaining member to the one axial side relative to the output member.

12. A reverse input cutoff clutch as set forth in any one of claims 1 to 11, further comprising an urging member that elastically urges said engaging element in a direction approaching said pressed surface in relation to said first direction.

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

14. A reverse input cut-off clutch as described in 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 constituted by a leaf spring elastically sandwiched between the output side engaging portion and the engaging element in the first direction.

15. A reverse input cut-off clutch as described in claim 13, wherein the connection portion of the retaining member is arranged on either side 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 constituted by two connection portions each having a retaining hole extending in the first direction, and the biasing member is constituted by two compression coil springs which 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.

16. A reverse input cutoff clutch as set forth in claim 15, further comprising a pressure piece attached to an end of each of the two compression coil springs in the extension direction, and each of the two compression coil springs elastically presses both side portions of the engagement element via the pressure piece.

17. A reverse input cut-off clutch as claimed in claim 15 or 16, wherein the engaging element is constituted by two engaging elements, the input side engaging portion is constituted by two input side engaging portions, the retaining hole is constituted by a through hole penetrating in the first direction, and each of the two compression coil springs is elastically compressed in the first direction between the two engaging elements.

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

19. A reverse input cutoff clutch according to any one of claims 1 to 16, wherein the engaging element is made up of two engaging elements, and the input side engaging portion is made up of two input side engaging portions.

20. A method for assembling a reverse input cut-off clutch comprising the biasing member as defined in claim 17 or 19, comprising the steps 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, displace the two engaging elements in a direction radially closer to each other against the elastic biasing force of the biasing member, and then inserting the two engaging elements axially into the radially inner side of the pressed surface.

Images