Reverse input cut-off clutch

Abstract

To provide a reverse input cut-off clutch capable of effectively preventing a moment load from being applied from a biasing plate spring to an engaging element.SOLUTION: A biasing plate spring 40 is disposed spaced apart in a second direction orthogonal to both an axial direction and a first direction, and has a pair of support plate portions 45 that engage with an engaging element 5, and a pressed plate portion 43 connecting the pair of support plate portions 45. An output member 4 has, at a central position in the second direction, an output-side pressing portion 23 that presses the pressed plate portion 43 toward a side closer to a pressed surface 6 with respect to the first direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

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

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

[0004] International Publication No. 2023 / 136149 describes a locking reverse input disconnection clutch that includes a pressed member, an input member, an output member, an engaging element, and a biasing leaf spring.

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

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

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

[0008] The engaging element has a pressing surface facing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and is arranged so as to be able to move in a first direction, which is the direction towards or away from the pressed surface.

[0009] When a rotational torque is input to the input member, the input side engaging portion engages with the input side engaged portion, and the engaging element moves in a direction away from the pressed surface, thereby engaging the output side engaged portion with the output side engaging portion, thereby transmitting the rotational torque input to the input member to the output member.

[0010] In contrast, when a rotational torque is reversely input to the output member, the engaging element moves in a direction approaching the pressed surface based on the engagement of the output-side engaging portion with the output-side engaged portion, and presses the pressing surface against the pressed surface, thereby frictionally engaging the pressing surface with the pressed surface. This achieves a locked state in which the rotational torque reversely input to the output member is completely blocked and not transmitted to the input member, or a semi-locked state in which only a portion of the rotational torque reversely input to the output member is transmitted to the input member and the remainder is blocked.

[0011] The biasing leaf spring is elastically sandwiched between the output member and the engaging element, and elastically biases the engaging element in a direction approaching the pressed surface in a first direction.

[0012] Therefore, according to the reverse input cutoff clutch described in WO 2023 / 136149, rattle of the engaging element in the first direction can be suppressed. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] International Publication No. 2023 / 136149 Brochure Summary of the Invention [Problem to be solved by the invention]

[0014] The conventional reverse input cutoff clutch described in WO 2023 / 136149 needs improvement in terms of stabilizing the posture of the engaging element when the engaging element moves toward the pressed surface in the first direction when a rotational torque is reversely input to the output member, and appropriately transitioning to a locked state or a semi-locked state. This point will be explained using the schematic diagrams shown in Figures 15(a) and 15(b).

[0015] 15(a) and 15(b) are cross-sectional views of a conventional reverse input cutoff clutch, showing only the output member, the engaging element, and the biasing leaf spring, taken along an imaginary plane perpendicular to the rotational center axis of the output member at the position where the output member presses the biasing leaf spring. Also, Fig. 15(a) shows a state in which, due to input of rotational torque to the input member, the engaging element has moved to a position farthest from the pressed surface and the output member has been placed in a neutral position in the rotational direction relative to the engaging element, while Fig. 15(b) shows a state in which rotational torque is reversely input to the output member.

[0016] In a conventional reverse input cutoff clutch, the biasing leaf spring 100 is arranged spaced apart in a second direction (left-right direction in Figures 15(a) and 15(b)) perpendicular to both the axial direction (front-to-back direction in Figures 15(a) and 15(b)) and the first direction (up-and-down direction in Figures 15(a) and 15(b)), and has a pair of support plate portions (axial plate pieces) 102 that engage with the engaging elements 101, and a pair of pressed plate portions (widthwise plate pieces and connecting portions) 103 that connect the pair of support plate portions 102 to each other at positions offset from the engaging elements 101 on both sides in the axial direction.

[0017] In a conventional reverse input cut-off clutch, the output side engaging portion of the output member 104, which is the portion that engages with the engaging element 101, and the output side pressing portion 105, which is the portion that engages with the pressed plate portion 103, have the same cross-sectional shape, specifically, an approximately rectangular or approximately oval cross-sectional shape, when cut in an imaginary plane perpendicular to the central axis of rotation of the output member 104.

[0018] 15(a), that is, in a state where a rotational torque is input to the input member, causing the engaging element 101 to move to a position farthest from the pressed surface, and where the output member 104 is disposed in a neutral position in the rotational direction relative to the engaging element 101, the output-side pressing portion 105 uniformly presses, with both longitudinal end portions, two locations (portions P) spaced apart in the second direction on the pressed plate portion 103. Therefore, in the state shown in FIG. 15(a), the engaging element 101 is uniformly pressed at two locations (portions Q) spaced apart in the second direction by the pair of support plate portions 102.

[0019] In contrast, when a rotational torque is input in reverse to the output member 104 from the state shown in Figure 15(a) as shown in Figure 15(b), causing the output member 104 to rotate in either direction (clockwise in the illustrated example), the biased leaf spring 100 elastically sandwiched between the output member 104 and the engaging element 101 is elastically deformed before the output side engaging portion engages with the output side engaged portion of the engaging element 101.

[0020] That is, when the output member 104 rotates in either direction, the end portion of the output-side pressing portion 105 on one side in the longitudinal direction (the left side in the illustrated example) is displaced in a direction approaching the engaging element 101 in the first direction, and the end portion on the other side in the longitudinal direction (the right side in the illustrated example) is displaced in a direction away from the engaging element 101 in the first direction. Therefore, the force with which the output-side pressing portion 105 presses the pressed plate portion 103 is greater at the end portion on one side in the longitudinal direction of the output-side pressing portion 105 and is smaller at the end portion on the other side in the longitudinal direction of the output-side pressing portion 105. Accordingly, of the pair of support plate portions 102 arranged spaced apart in the second direction, the force with which the support plate portion 102 on one side in the second direction presses the engaging element 101 is greater, and the force with which the support plate portion 102 on the other side in the second direction presses the engaging element 101 is smaller. As a result, a moment load M acts on the engaging element 101 from the biasing leaf spring 100 .

[0021] In a locking type reverse input cut-off clutch, when a rotational torque is reversely input to the output member 104, from the viewpoint of stabilizing the posture of the engaging element 101 as it moves in the direction approaching the pressed surface in the first direction (upward in Figures 15(a) and 15(b)) and appropriately transitioning to the locked state or semi-locked state, it is desirable to prevent a moment load M from acting on the engaging element 101 as the amount of elastic deformation of the biasing leaf spring 100 becomes uneven in the second direction.

[0022] An object of the present disclosure is to provide a reverse input cutoff clutch that can effectively prevent a moment load from acting on an engagement element from a biasing leaf spring. [Means for solving the problem]

[0023] The reverse input disconnecting clutch of the first aspect of the present disclosure includes: a pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion disposed radially inside the pressed surface and disposed coaxially with the pressed surface; an output member having an output side engaging portion disposed radially inward of the input side engaging portion and disposed coaxially with the pressed surface; an engaging element having a pressing surface facing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and arranged to be movable in a first direction which is a direction in which the pressing surface approaches or moves away from the pressed surface; a biasing leaf spring that is elastically sandwiched between the output member and the engaging element and that elastically biases the engaging element in a direction that brings it closer to the pressed surface; Equipped with.

[0024] 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.

[0025] The biasing plate spring is arranged spaced apart in a second direction perpendicular to both the axial direction and the first direction, and has a pair of support plate portions that engage with the engaging elements, and a pressed plate portion that connects the pair of support plate portions to each other.

[0026] The output member has an output-side pressing portion at a central position in the second direction that presses the pressed plate portion toward a side closer to the pressed surface in the first direction.

[0027] In the reverse input disconnection clutch of the second aspect of the present disclosure, in the reverse input disconnection clutch of the first aspect of the present disclosure, the output side pressing portion is configured by a partial cylindrical surface centered on the rotational center axis of the output member or an axis parallel to the rotational center axis.

[0028] In a third aspect of the present disclosure, in the reverse input disconnection clutch of the first or second aspect of the present disclosure, The pressed plate portion is composed of a pair of pressed plate portions disposed at positions offset from the engaging element on both sides in the axial direction, The output-side pressing portion is configured by a pair of output-side pressing portions that are arranged at positions overlapping the pair of pressed plate portions in the first direction.

[0029] A fourth aspect of the present disclosure is a reverse input disconnection clutch, wherein in the reverse input disconnection clutch of the third aspect of the present disclosure, the output member has a pair of regulating portions that protrude from portions adjacent to both axial sides of the output-side engaging portion toward a side closer to the pressed surface in the first direction and are arranged at positions that sandwich the engaging element from both axial sides, and the pair of regulating portions regulate axial movement of the engaging element relative to the output member, The pair of output-side pressing portions are configured by tip surfaces of the pair of restricting portions that face the pressed surface side in the first direction.

[0030] A fifth aspect of the present disclosure is a reverse input disconnection clutch, in the fourth aspect of the present disclosure, the output member includes a main body portion including the output-side engaging portion, and a pair of restricting components coupled and fixed to the main body portion, The pair of restricting portions is constituted by the pair of restricting parts.

[0031] A reverse input cutoff clutch according to a sixth aspect of the present disclosure is the reverse input cutoff clutch according to any one of the first to fifth aspects of the present disclosure, wherein the engagement element is configured by two engagement elements. [Effects of the Invention]

[0032] According to the reverse input cutoff clutch of one aspect of the present disclosure, it is possible to effectively prevent a moment load from acting on the engagement element from the biasing leaf spring. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a cross-sectional view of a reverse input cutoff clutch according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an exploded perspective view of the reverse input cutoff clutch of the first example. [Figure 3] FIG. 3 is an enlarged view of part A in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line BB in FIG. 1, with some parts omitted. [Figure 5] FIG. 5 is a cross-sectional view taken along CC in FIG. 1, with the two biasing leaf springs omitted. [Figure 6] FIG. 6 is a view similar to FIG. 5, showing a state in which a rotational torque is input to the input member. [Figure 7] FIG. 7 is a view similar to FIG. 5, showing a state in which a rotational torque is reversely input to the output member. [Figure 8] FIG. 8(a) is a plan view of the biasing leaf spring of the first example as seen from the engaging element side in the first direction, and FIG. 8(b) is a side view of the biasing spring as seen from below in FIG. 8(a). [Figure 9] Figures 9(a) and 9(b) are cross-sectional views of the output member of the first example, cut by an imaginary plane perpendicular to the axial direction at the axial position where the output side pressing portion is located. Figure 9(a) shows a state in which no rotational torque is reversely input to the output member and the longitudinal direction of the output side engaging portion and the radial inner surface of the engaging element are arranged parallel to each other, and Figure 9(b) shows a state in which rotational torque is reversely input to the output member and the output member is rotating. [Figure 10] 10(a) and 10(b) are diagrams corresponding to FIGS. 9(a) and 9(b) for a second example of an embodiment of the present disclosure. [Figure 11] 11(a) and 11(b) are diagrams corresponding to FIGS. 9(a) and 9(b) for a third example of an embodiment of the present disclosure. [Figure 12] FIG. 12 is a diagram corresponding to FIG. 3 and illustrating a reverse input cutoff clutch according to a fourth example of an embodiment of the present disclosure. [Figure 13] FIG. 13(a) is a perspective view of an output member of the fourth example, and FIG. 13(b) is an exploded perspective view of the output member of the fourth example. [Figure 14]FIG. 14(a) is a plan view of the output member of the fourth example as seen from the first direction, and FIG. 14(b) is a cross-sectional view taken along line DD of FIG. 14(a). [Figure 15] Figures 15(a) and 15(b) show cross-sectional views of a conventional reverse input cutoff clutch, with only the output member, engaging element, and biasing leaf spring taken out, of the reverse input cutoff clutch, cut by an imaginary plane perpendicular to the rotational center axis of the output member at the position where the output member presses the biasing leaf spring. Figure 15(a) shows a state in which rotational torque is input to the input member, causing the engaging element to move to a position farthest from the pressed surface, and the output member is positioned in a neutral position in the rotational direction relative to the engaging element, and Figure 15(b) shows a state in which rotational torque is reversely input to the output member. DETAILED DESCRIPTION OF THE INVENTION

[0034] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 9(b).

[0035] In the following description, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the reverse input disconnection clutch 1, more specifically the axial direction, radial direction, and circumferential direction of the pressed surface 6 of the pressed member 2 that constitutes the reverse input disconnection clutch 1. In this example, the axial direction, radial direction, and circumferential direction of the reverse input disconnection clutch 1 coincide with the axial direction, radial direction, and circumferential direction of the input member 3, and also coincide with the axial direction, radial direction, and circumferential direction of the output member 4. One axial side is the input member 3 side (right side in FIG. 1), and the other axial side is the output member 4 side (left side in FIG. 1).

[0036] The direction of the pressing surface 34 of the engaging element 5 toward or away from the pressed surface 6 is defined as a first direction (the up-and-down direction in Figs. 1 and 3 to 7), and the direction perpendicular to both the axial direction of the pressed surface 6 and the first direction is defined as a second direction (the front-to-back direction in Figs. 1 and 3, the left-to-right direction in Figs. 4 to 7). The radial direction of the engaging element 5 (the direction indicated by arrow A in Fig. 5) corresponds to the first direction, and the width direction of the engaging element 5 (the direction indicated by arrow B in Fig. 5) corresponds to the second direction.

[0037] <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 an urging leaf spring 40 formed of a leaf spring. When a rotational torque is input to the input member 3, the engaging element 5 moves in a direction away from the pressed member 2 based on the engagement between the input member 3 and the engaging element 5, engaging the output member 4 and transmitting the rotational torque input to the input member 3 to the output member 4. On the other hand, when a rotational torque is input in reverse to the output member 4, the engaging element 5 presses the pressing surface of the engaging element 5 against the pressed surface of the pressed member 2 based on the engagement between the output member 4 and the engaging element 5, causing frictional engagement. As a result, the reverse input cutoff clutch 1 transmits the rotational torque input to the input member 3 to the output member 4, while completely cutting off the rotational torque input in reverse to the output member 4 so that it is not transmitted to the input member 3, or transmits only a portion of the torque to the input member 3 and cuts off the remainder, thereby providing a reverse input cutoff function. The biasing leaf spring 40 elastically biases the engaging element 5 in a direction that brings it closer to the pressed surface 6, thereby preventing the engaging element 5 from rattling inside the pressed surface 6.

[0038] The materials for the pressed member 2, input member 3, output member 4, and engaging element 5 are not particularly limited as long as they can ensure the necessary mechanical properties such as strength. For example, these materials can be metals such as iron alloys, copper alloys, and aluminum alloys, as well as synthetic resins mixed with reinforcing fibers as needed. Furthermore, the pressed member, input member, output member, and engaging element can be made of the same material or different materials.

[0039] As long as the condition that the output member 4 is locked or semi-locked when a rotational torque is input in reverse to the output member 4 is met, a lubricant can be applied to the contact points between the pressed member 2, input member 3, output member 4, and engaging element 5. Alternatively, at least one of the pressed member 2, input member 3, output member 4, and engaging element 5 can be made of oil-impregnated metal.

[0040] The pressed member 2 has a pressed surface 6 on its inner circumferential surface.

[0041] The pressed member 2 is supported and fixed to a fixed part such as a housing that does not rotate even when in use, and its rotation is restricted, or it is constituted by the fixed part. In other words, the pressed member 2 does not rotate even when in use. In this example, the pressed member 2 is supported and fixed to the fixed part, and its rotation is restricted.

[0042] The pressed surface 6 has a circular ring shape when viewed in the axial direction, and in this example has a cylindrical surface shape whose inner diameter does not change in the axial direction, although this is not limited to this.

[0043] The input-side engaging portion 13 of the input member 3 and the output-side engaging portion 17 of the output member 4 are coaxially arranged on the radially inner side of the pressed surface 6, and the engaging element 5 is arranged so as to be movable towards and away from the pressed surface 6. The input-side engaging portion 13, the output-side engaging portion 17, and the engaging element 5 are rotatable on the radially inner side of the pressed surface 6. The pressed surface 6 forms a surface that comes into contact with the pressing surface 34 of the engaging element 5 when the engaging element 5 moves in a direction approaching the pressed surface 6.

[0044] There are no limitations on the structure of the pressed member 2 as long as it has a pressed surface 6 on its inner circumferential surface. The pressed member 2 can be formed of a single member having the pressed surface 6, or can be formed by combining, for example, an input side element and an output side element, either of which has the pressed surface 6.

[0045] In this example, the pressed member 2 includes an output element 7 having a pressed surface 6, and an input element (not shown).

[0046] The output element 7 has an inner peripheral surface shaped like a stepped cylindrical surface. That is, the inner peripheral surface of the output element 7 is provided with a large-diameter cylindrical surface portion 8 on one axial side, a small-diameter cylindrical surface portion 9 on the other axial side, and a connecting surface portion 10 facing one axial side and connecting the large-diameter cylindrical surface portion 8 and the small-diameter cylindrical surface portion 9. In this example, the large-diameter cylindrical surface portion 8 forms the pressed surface 6. The output element 7 has an inward flange portion 11 that protrudes radially inward at the end on the other axial side of the small-diameter cylindrical surface portion 9.

[0047] In this example, the input element is fitted (spigot-fitted) to the output element 7 without any rattle, and the output element 7 and the input element are positioned radially, and then the output element 7 and the input element are joined together with a joining member such as a bolt to form the pressed member 2. The pressed member 2 is supported and fixed to the fixed portion by threading a bolt inserted into a through-hole provided in the fixed portion into a screw hole 12 opening on the side surface of the output element 7 on the other axial side.

[0048] The input member 3 has an input-side engaging portion 13 arranged radially inside the pressed surface 6 , and is arranged coaxially with the pressed surface 6 .

[0049] The input member 3 is connected to an input side mechanism such as an electric motor, and receives a rotational torque, and is configured to be rotatable on the radially inner side of the pressed surface 6 by the input of the rotational torque.

[0050] The input-side engaging portion 13 is provided at a portion radially outwardly deviated from the central axis O of rotation of the input member 3, and is arranged at a position where it can engage with the input-side engaged portion 35 of the engaging element 5. The input-side engaging portion 13 is configured so that its radially inner surface 15 engages with, or more specifically comes into contact with, the radially inner surface 37 of the input-side engaged portion 35 as the input member 3 or the engaging element 5 rotates.

[0051] The input-side engaging portion 13 can be attached directly to the output shaft of the input-side mechanism, or can be attached to an input shaft portion that is provided on the input member 3 and connected to the input-side mechanism. In this example, the input member 3 has an input shaft portion 14 in addition to the input-side engaging portion 13.

[0052] The input shaft portion 14 has a substantially cylindrical shape.

[0053] The input member 3 can be rotatably supported by the pressed member 2 or the fixed portion. In this example, the input shaft 14 of the input member 3 is rotatably supported inside the input element by a radial bearing. The input shaft 14 is connected to the input mechanism.

[0054] The input side engaging portion 13 protrudes from a portion of the end face on the other axial side of the input shaft portion 14 that is radially outwardly spaced from the rotation center axis O toward the other axial side.

[0055] The shape of the input side engaging portion 13 is not limited as long as it is configured to engage with the input side engaged portion 35 of the engaging element 5. For example, the input side engaging portion 13 may have a shape that is symmetrical in the circumferential direction, or may have a shape that is asymmetrical in the circumferential direction. In this example, the input side engaging portion 13 has a shape that is symmetrical in the circumferential direction.

[0056] In this example, the input-side engaging portion 13 has a generally arch-shaped configuration when viewed in the axial direction. Of the radially inner surface 15 of the input-side engaging portion 13, a circumferentially intermediate portion is configured as a flat surface perpendicular to a line connecting the rotation axis O and the center of the input-side engaging portion 13 when viewed in the axial direction, and both circumferential side portions are configured as partially cylindrical convex surfaces that slope radially outward toward both circumferential sides. The radially outer surface 16 of the input-side engaging portion 13 is configured as a partially cylindrical convex surface centered on the rotation axis O.

[0057] The number of input side engaging portions 13 is determined according to the number of engaging elements 5, and when the engaging elements 5 are made up of a plurality of engaging elements 5, the input side engaging portion 13 is also made up of a plurality of input side engaging portions 13.

[0058] In the reverse input cutoff clutch 1 of this example, the engaging elements 5 are configured by two engaging elements 5. Therefore, the input side engaging portion 13 is configured by two input side engaging portions 13 to match the number of engaging elements 5. The two input side engaging portions 13 are arranged at two radially opposite positions on the radially outer side of the end face on the other axial side of the input shaft portion 14, and are spaced apart from each other in the radial direction of the input member 3.

[0059] The output member 4 has an output-side engaging portion 17 that is arranged radially inward of the input-side engaging portion 13, and is arranged coaxially with the pressed surface 6. The output member 4 is also arranged coaxially with the input member 3, radially inward of the pressed surface 6.

[0060] The output member 4 is connected to an output side mechanism such as a speed reduction mechanism, and is configured to output a rotational torque to the output side mechanism as it rotates.

[0061] The output side engaging portion 17 has a portion that can engage with the output side engaged portion 36 of the engaging element 5, and this engageable portion is located radially inward of the input side engaging portion 13 and radially outward from the rotation center axis O of the output member 4, and is arranged at a position where it can engage with the output side engaged portion 36 of the engaging element 5. The output side engaging portion 17 is configured so that this portion engages with the output side engaged portion 36 as the output member 4 or the engaging element 5 rotates.

[0062] The shape of the output side engaging portion 17 is not limited as long as it has a portion that can engage with the output side engaged portion 36 .

[0063] The number of portions of the output side engaging portion 17 that engage with the output side engaged portions 36 is determined according to the number of engaging elements 5, and when the engaging element 5 is made up of a plurality of engaging elements 5, the output side engaging portion 17 is also configured to have a plurality of engaging portions. In this example, the output side engaging portion 17 is configured to have portions that engage with two of the output side engaged portions 36, matching the number of engaging elements 5.

[0064] The output-side engaging portion 17 has a cam function. That is, the distance from the rotational center axis O of the output member 4 to the outer circumferential surface of the output-side engaging portion 17, which is the portion that engages with the output-side engaged portion 36, is not constant in the circumferential direction.

[0065] The cross-sectional shape of the output-side engaging portion 17 when cut along an imaginary plane perpendicular to the central axis O of rotation of the output member 4 can be any shape as long as the output-side engaging portion 17 has a cam function, and can be, for example, a substantially rectangular or oval shape, a parallelogram, a trapezoid, or the like. In this example, the output-side engaging portion 17 has a substantially rectangular or oval cross-sectional shape when cut along an imaginary plane perpendicular to the central axis O of the rotation of the output member 4, as shown in FIG. 5. The outer circumferential surface of the output-side engaging portion 17 is made up of side surfaces 24 on both sides in the short direction of the cross-sectional shape (the short axis direction, the up-and-down direction in FIGS. 1, 3, 4, and 5) and end surfaces 25 on both sides in the long direction of the cross-sectional shape (the long axis direction, the front-to-back direction in FIGS. 1 and 3, the left-to-right direction in FIGS. 4 and 5).

[0066] The longitudinally intermediate portion of the side surface 24 is formed by a flat surface perpendicular to the lateral direction. The longitudinally opposite end portions of the side surface 24 are formed by partially cylindrical convex surfaces that are inclined toward the center in the lateral direction as they extend toward both ends in the longitudinal direction. The end surface 25 is formed by a partially cylindrical convex surface centered on the central axis O of rotation of the output member 4.

[0067] In this example, the output side engaging portion 17 is plane-symmetrical with respect to an imaginary plane that passes through the rotation center axis O of the output member 4 and is parallel to the short side direction. Furthermore, the output side engaging portion 17 is plane-symmetrical with respect to an imaginary plane that passes through the rotation center axis O of the output member 4 and is parallel to the longitudinal direction. In other words, the output side engaging portion 17 has a shape that is two-fold symmetrical with respect to the central axis of the output member 4. The output side engaging portion 17 is disposed radially inward of the two input side engaging portions 13 and between the output side engaged portions 36 of the two engaging elements 5.

[0068] The output member 4 has an output side pressing portion 23 at a central position in the second direction that presses a pressed plate portion 43 of a biasing plate spring 40 (described later) toward a side closer to the pressed surface 6 in the first direction.

[0069] It should be noted that with respect to the output member 4, the first direction and the second direction refer to the first direction and the second direction of the engaging element 5 when no torque is reversely input to the output member 4 and the longitudinal direction of the output side engaging portion 17 and the radial inner surface (flat surface portion 38) of the engaging element 5 are arranged parallel to each other.

[0070] The output side pressing portion 23 is positioned at an axial position where it can press the pressed plate portion 43 of the biasing plate spring 40 toward the side closer to the pressed surface 6 in the first direction, i.e., at an axial position where it overlaps with the pressed plate portion 43 in the first direction.

[0071] When implementing the present disclosure, the pressed plate portion 43 of the biasing leaf spring 40 can be arranged in a portion axially offset from the engaging element 5, or can be arranged in a portion overlapping with the engaging element 5 in the first direction. In the reverse input cutoff clutch 1 of this example, the pressed plate portion 43 of the biasing leaf spring 40 is composed of a pair of pressed plate portions 43 arranged in portions offset on both axial sides from the engaging element 5. Therefore, in this example, the output side pressing portion 23 is composed of a pair of output side pressing portions 23 arranged in an axial position overlapping with the pair of pressed plate portions 43 in the first direction.

[0072] In this example, the output member 4 has a pair of restricting portions 18a, 18b that protrude radially outward from portions adjacent to both axial sides of the output-side engaging portion 17, i.e., protrude toward the side closer to the pressed surface 6 in the first direction, and are arranged to sandwich the engaging element 5 from both axial sides, and the pair of restricting portions 18a, 18b restricts axial movement of the engaging element 5 relative to the output member 4. The pair of restricting portions 18a, 18b have tip surfaces 44 that face the pressed surface 6 side in the first direction. In this example, the pair of output-side pressing portions 23 are formed by the tip surfaces 44 of the pair of restricting portions 18a, 18b.

[0073] The pair of restricting portions 18a, 18b may be formed integrally with or separately from other portions of the output member 4. In this example, the pair of restricting portions 18a, 18b are formed integrally with other portions of the output member 4, i.e., are formed integrally with the output member 4. Specifically, the pair of restricting portions 18a, 18b are formed so as to protrude from portions of the output member 4 adjacent to both axial sides of the side surface 24 of the output-side engaging portion 17 toward the side closer to the pressed surface 6 in the first direction.

[0074] The first direction dimension (radial height) and second direction dimension, as well as the shape of each of the pair of regulating portions 18a, 18b, can be set arbitrarily as long as the pair of regulating portions 18a, 18b can effectively regulate the axial movement of the engaging member 5 relative to the output member 4.

[0075] The first and / or second dimension of each of the restriction portions 18a, 18b constituting the pair of restriction portions 18a, 18b can be the same as or different from each other. In this example, the first and second dimension of each of the restriction portions 18a, 18b constituting the pair of restriction portions 18a, 18b are the same as each other.

[0076] The axial width of each of the regulating portions 18a, 18b that make up the pair of regulating portions 18a, 18b can be set arbitrarily as long as the strength and functionality required of the regulating portions 18a, 18b can be ensured, and the smaller the axial width of the regulating portions 18a, 18b, the more it can contribute to shortening the axial dimension of the reverse input cut-off clutch 1.

[0077] The axial widths of the respective restricting portions 18a, 18b constituting the pair of restricting portions 18a, 18b can be the same for the respective restricting portions 18a, 18b, or can be different for the respective restricting portions 18a, 18b. In this example, the axial widths of the respective restricting portions 18a, 18b constituting the pair of restricting portions 18a, 18b are the same for the respective restricting portions 18a, 18b.

[0078] In this example, as shown in FIGS. 2 and 4, each of the pair of restricting portions 18a, 18b has an end face shape of a substantially isosceles triangle when viewed in the axial direction.

[0079] Of the tip surfaces 44 of the pair of restricting portions 18a, 18b, the central portions in the second direction form the output-side pressing portion 23.

[0080] The shape of the output side pressing portion 23 is not limited as long as it is configured to press the pressed plate portion 43 of the biasing plate spring 40 toward the side closer to the pressed surface 6 in the first direction.

[0081] The output-side pressing portion 23 can be formed, for example, by a partial cylindrical surface centered on the rotation axis O of the output member 4 or an axis parallel to the rotation axis O. In this example, the output-side pressing portion 23 is formed by a partial cylindrical surface centered on the rotation axis O of the output member 4 and having a curvature radius of R1 ( FIG. 9( a)). Therefore, in this example, regardless of the rotation position of the output member 4, the position at which the output-side pressing portion 23 presses the pressed plate portion 43 hardly changes in the longitudinal direction of the output-side engaging portion 17. This configuration effectively prevents moment load from acting on the engaging element 5 from the output-side pressing portion 23 via the biasing leaf spring 40.

[0082] Both side portions of the tip surfaces 44 of the pair of regulating portions 18a, 18b in the second direction are configured with inclined surface portions 26 that are inclined in a direction away from the pressed surface 6 in the first direction as they move away from the output-side pressing portion 23 in the second direction. Regardless of the direction in which the output member 4 rotates relative to the engaging element 5, the inclined surface portions 26 of the tip surfaces 44 of the pair of regulating portions 18a, 18b do not contact the pressed plate portions 43. Note that, when implementing the present disclosure, each tip surface 44 can be configured entirely as a partial cylindrical surface, and the central portion of the partial cylindrical surface in the second direction can press the central portion of the pressed plate portion 43 in the second direction. Also, when implementing the present disclosure, each of the regulating portions 18a, 18b constituting the pair of regulating portions 18a, 18b can be configured as a protrusion having only the output-side pressing portion 23 on the tip surface 44.

[0083] In this example, of the pair of restricting portions 18a, 18b, the restricting portion 18a on one axial side has a restricting surface 27a on the other axial side. The restricting surface 27a is formed of a flat surface perpendicular to the axial direction. Of the pair of restricting portions 18a, 18b, the restricting portion 18a on the other axial side has a restricting surface 27b on the one axial side. The restricting surface 27b is formed of a flat surface perpendicular to the axial direction.

[0084] In this example, corner rounding portions 42 having a concave arc cross section are provided at the connection portions between the side surface 24 provided on the outer peripheral surface of the output side engaging portion 17 and each of the restricting surfaces 27a, 27b, as shown in Fig. 3. This makes it possible to alleviate stress applied to the connection portions between the side surface 24 and the restricting surfaces 27a, 27b.

[0085] The number of output side pressing portions 23 (in this example, the number of pairs of regulating portions 18a, 18b each having an output side pressing portion 23) is determined according to the number of sets of engaging elements 5 and biasing leaf springs 40, and when the engaging elements 5 and biasing leaf springs 40 are composed of multiple sets of engaging elements 5 and biasing leaf springs 40, the output side pressing portion 23 (in this example, a pair of regulating portions 18a, 18b each having an output side pressing portion 23) is also composed of multiple output side pressing portions 23.

[0086] In this example, the engaging elements 5 and the biasing leaf springs 40 are configured by two sets of engaging elements 5 and biasing leaf springs 40. Therefore, in this example, the pair of restricting portions 18a, 18b, each having the output-side pressing portion 23, is configured by two pairs of restricting portions 18a, 18b, matching the number of sets of engaging elements 5 and biasing leaf springs 40. In this example, each pair of restricting portions 18a, 18b is provided so as to protrude in a direction approaching the pressed surface 6 in the first direction from portions of the outer peripheral surface of the output member 4 that are adjacent to both axial sides of two side surfaces 24 arranged on both sides of the output-side engaging portion 17 in the short direction.

[0087] The portions of the output member 4 adjacent to both axial sides of the output side engagement portion 17, i.e., the side surfaces on both sides in the second direction of the axial portion of the output member 4 where the pair of regulating portions 18a, 18b are located, are composed of partially cylindrical convex surfaces arranged in the same imaginary cylindrical plane as the end face 25 of the output side engagement portion 17.

[0088] The reverse input cutoff clutch 1 of this example uses a pair of restricting portions 18a, 18b provided on the output member 4 to restrict axial movement of the engaging element 5 relative to the output member 4. This prevents the engaging element 5 from falling in the axial direction, making it easy to properly maintain the contact state between the pressing surface 34 and the pressed surface 6. In the reverse input cutoff clutch 1 of this example, the pair of restricting portions 18a, 18b are integrally formed with the output member 4, so the number of parts can be reduced compared to when a separate part such as a spacer is provided to restrict axial movement of the engaging element 5 relative to the output member 4. This prevents the cost of managing parts from increasing.

[0089] In this example, the output-side engaging portion 17 and the respective restricting portions 18a, 18b are provided on an intermediate shaft portion 19 provided in the axial middle portion of the output member 4. In addition to the intermediate shaft portion 19, the output member 4 has an output shaft portion 20 and a small diameter shaft portion 21. In particular, in this example, the output member 4 has the intermediate shaft portion 19, the output shaft portion 20, and the small diameter shaft portion 21 integrally configured.

[0090] The output shaft portion 20 has a stepped cylindrical shape and is provided adjacent to the other axial side of the intermediate shaft portion 19. The output shaft portion 20 has an output flange portion 22 that protrudes radially outward from an end portion on one axial side over the entire circumference. The intermediate shaft portion 19 protrudes toward one axial side from the center of an end face 41 on one axial side of the output shaft portion 20.

[0091] The small diameter shaft portion 21 protrudes axially toward one side from the center of an end face on one axial side of the intermediate shaft portion 19. The small diameter shaft portion 21 has a cylindrical shape.

[0092] The output member 4 can be rotatably supported on the pressed member 2 or the fixed portion. In this example, the output member 4 is rotatably supported radially inside the output element 7 of the pressed member 2 by a radial rolling bearing 28. The outer ring 29 of the radial rolling bearing 28 is fitted securely into the small-diameter cylindrical surface portion 9 of the output element 7 and is axially sandwiched between a side surface on one axial side of the inward flange portion 11 and a segmented annular retaining ring 32a engaged with one axial end of the small-diameter cylindrical surface portion 9. The inner ring 30 of the radial rolling bearing 28 is fitted securely onto the end of one axial side of the output shaft portion 20 and is axially sandwiched between a side surface on the other axial side of the output flange portion 22 and a segmented annular retaining ring 32b engaged with the outer peripheral surface of an axially intermediate portion of the output shaft portion 20.

[0093] In the illustrated example, the radial rolling bearing 28 is configured as a ball bearing that uses balls as rolling elements 31. However, the radial rolling bearing for supporting the output member 4 can also be configured as a tapered roller bearing that uses tapered rollers as rolling elements or a roller bearing that uses cylindrical rollers.

[0094] The small diameter shaft portion 21 of the output member 4 is supported by a slide bearing (sleeve) 33 on the inside of the input shaft portion 14 of the input member 3 so as to be able to rotate freely relative to the input member 3.

[0095] The engaging element 5 has a pressing surface 34 facing the pressed surface 6, an input side engaged portion 35 engageable with the input side engaging portion 13, and an output side engaged portion 36 engageable with the output side engaging portion 17, and is arranged so as to be able to move in a first direction, which is the direction towards or away from the pressed surface 6.

[0096] When a rotational torque is input to the input member 3, the engaging element 5 moves in a direction away from the pressed surface 6 in the first direction based on the engagement of the input side engaging portion 13 with the input side engaged portion 35, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output side engaged portion 36 with the output side engaging portion 17, whereas when a rotational torque is input in the reverse direction to the output member 4, the output side engaging portion 17 engages with the output side engaged portion 36, pressing the pressing surface 34 against the pressed surface 6 and frictionally engaging the pressing surface 34 with the pressed surface 6.

[0097] In this example, the engaging element 5 has a substantially semicircular end face shape when viewed from the axial direction, and has a shape that is symmetrical with respect to the width direction.

[0098] The pressing surface 34 is provided on the radially outer surface of the engaging element 5 facing the pressed surface 6. In this example, the pressing surface 34 is composed of two pressing surfaces 34 provided at two positions spaced apart from each other in the circumferential direction on the radially outer surface of the engaging element 5. Each pressing surface 34 is composed of a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface 6.

[0099] When viewed from the axial direction, the portion of the radially outer surface of the engaging element 5 that is circumferentially offset from the two pressing surfaces 34 is located radially inward of an imaginary circle that is centered on the rotational center axis O of the input member 3 and that is tangent to the two pressing surfaces 34. In other words, when the two pressing surfaces 34 are in contact with the pressed surface 6, the portion that is circumferentially offset from the two pressing surfaces 34 does not come into contact with the pressed surface 6.

[0100] The pressing surface 34 preferably has a surface property that gives it a higher coefficient of friction with the pressed surface 6 than the other parts of the engaging element 5. The pressing surface 34 can be formed integrally with the other parts of the engaging element 5, or can be formed by the surface of a friction material fixed to the other parts of the engaging element 5 by adhesion or the like.

[0101] In this example, the input side engaged portion 35 is provided at the radially middle portion of the widthwise center portion of the engaging element 5. The shape of the input side engaged portion 35 is not limited as long as it is configured to be able to engage with the input side engaging portion 13.

[0102] In this example, the input side engaged portion 35 has an approximately oval opening shape extending in the width direction of the engaging element 5 when viewed from the axial direction, and is composed of a through hole that penetrates the radially middle portion of the width direction center of the engaging element 5 in the axial direction.

[0103] The input-side engaged portion 35 has a size that allows the input-side engaging portion 13 to be loosely inserted therein. Therefore, when the input-side engaging portion 13 is inserted inside the input-side engaged portion 35, there is a gap between the input-side engaging portion 13 and the inner surface of the input-side engaged portion 35 in both the width direction and the radial direction of the engaging element 5. Therefore, the input-side engaging portion 13 can be displaced relative to the input-side engaged portion 35 in the rotational direction of the input member 3, and the input-side engaged portion 35 can be displaced in the radial direction of the engaging element 5 relative to the input-side engaged portion 13. In this example, of the inner surface of the input-side engaged portion 35, a radially inner surface 37 facing radially outward is formed by a flat surface perpendicular to the first direction.

[0104] In this example, the output-side engaged portion 36 is provided at the center in the width direction of the radially inner surface, which is the side surface of the engaging element 5 on the side opposite to the pressed surface 6 with respect to the first direction. The shape of the output-side engaged portion 36 is not limited as long as it is configured to be engageable with the output-side engaging portion 17.

[0105] In this example, the engaging element 5 has a flat surface portion 38 orthogonal to the radial direction on the radially inner surface, and two convex portions 39 protruding radially inward are provided at two positions in the width direction of the engaging element 5 of the flat surface portion 38. The output-side engaged portion 36 is constituted by a portion existing between the two convex portions 39 in the width direction of the flat surface portion 38. In this example, the width-direction dimension of the output-side engaged portion 36, that is, the interval between the two convex portions 39, is larger than the width-direction dimension in the longitudinal direction of the output-side engaging portion 17.

[0106] In this example, the axial thickness Wa of the engaging element 5 is set to a value slightly smaller than the interval Wb between the pair of regulating portions 18a and 18b in the axial direction, that is, the interval Wb between the pair of regulating surfaces 27a and 27b in the axial direction (Wa < Wb). Conversely, the interval Wb between the pair of regulating portions 18a and 18b in the axial direction is set to a value slightly larger than the axial thickness Wa of the engaging element 5. For this reason, the engaging element 5 is arranged between the pair of regulating portions 18a and 18b, the movement of the pressed surface 6 in the axial direction is regulated, and the movement in the first direction with respect to the pressed surface 6 is enabled.

[0107] In this example, the movement of the engaging element 5 to one side in the axial direction with respect to the output member 4 is regulated by the side surface on one side in the axial direction of the engaging element 5 abutting on the regulating surface 27a of the regulating portion 18a on one side in the axial direction. Further, the movement of the engaging element 5 to the other side in the axial direction with respect to the output member 4 is regulated by the side surface on the other side in the axial direction of the engaging element 5 abutting on the regulating surface 27b of the regulating portion 18b on the other side in the axial direction.

[0108] Furthermore, in this example, the axial thickness Wa of the engaging element 5 is set to a value slightly smaller than the distance Wc between the closer-side ends of the two corner R portions 42 located on both axial sides of the side surface 24 of the output-side engaging portion 17, that is, the axial width Wc of the side surface 24 (Wa < Wc). Conversely, the distance Wc between the closer-side ends of the two corner R portions 42 is set to a value slightly larger than the axial thickness Wa of the engaging element 5. This prevents the output-side engaged portion 36 from simultaneously contacting the two corner R portions 42, thereby preventing the output-side engaged portion 36 from being unable to contact the side surface 24.

[0109] Alternatively or additionally, chamfered portions each composed of a C-chamfered portion or an R-chamfered portion are formed at the connection portions between the side surfaces on both axial sides of the engaging element 5 and the output-side engaged portion 36. By means of such chamfered portions, it is also possible to prevent the output-side engaged portion 36 from simultaneously contacting the two corner R portions 42. If such chamfered portions are formed on the engaging element 5, while preventing the output-side engaged portion 36 from simultaneously contacting the two corner R portions 42, the axial thickness Wa of the engaging element 5 can be made larger than the axial width Wc of the side surface 24 (Wa > Wc), and the difference (Wb - Wa) between the axial thickness Wa of the engaging element 5 and the distance Wb between the pair of regulating surfaces 27a and 27b can be made smaller than in this example. As a result, the axial movement amount of the engaging element 5 between the pair of regulating portions 18a and 18b can be suppressed to be smaller than in this example.

[0110] As long as the engaging element 5 has such a configuration, it can be composed of one engaging element 5 or two or more engaging elements 5. In this example, the engaging element 5 is composed of two engaging elements 5. Each engaging element 5 has the function as an engaging element 5.

[0111] In the reverse input cutoff clutch 1 of this example, the pressing surfaces 34 of the two engaging elements 5 face radially opposite each other, and the flat surface portions 38 face each other, with each engaging element 5 disposed radially inward of the pressed surface 6 so as to be movable in a first direction. Furthermore, the two input-side engaging portions 13 of the input member 3 disposed on one axial side are axially inserted into the input-side engaged portions 35 of the two engaging elements 5, and the output-side engaging portion 17 of the output member 4 disposed on the other axial side is axially inserted between the output-side engaged portions 36 of the two engaging elements 5. In other words, the output-side engaged portions 36 of the two engaging elements 5 are disposed so as to sandwich the output-side engaging portion 17 from the radially outer side.

[0112] When the two engaging elements 5 are positioned radially inside the pressed surface 6, the inner diameter dimension of the pressed surface 6 and the radial dimension of the engaging elements 5 are regulated so that a gap exists in at least one of the areas between the pressed surface 6 and the pressing surface 34, the area between the output side engaging portion 17 and the output side engaged portion 36, and the area between the tip faces of the convex portions 39.

[0113] Furthermore, when the two engaging elements 5 are positioned radially inward of the pressed surface 6, the widthwise middle portion of the radially inner portion of each engaging element 5 is positioned between a pair of regulating portions 18a, 18b of the output member 4 in the axial direction.

[0114] The biasing leaf spring 40 is elastically sandwiched between the output member 4 and the engaging element 5, and elastically biases the engaging element 5 in a direction that brings it closer to the pressed surface 6. This effectively prevents the engaging element 5 from rattling inside the pressed surface 6.

[0115] The biasing plate spring 40 has a pair of support plate portions 45 that are arranged apart in the second direction and engage with the engaging element 5, and a pressed plate portion 43 that connects the pair of support plate portions 45. The pressed plate portion 43 forms a portion that is pressed by the output-side pressing portion 23 of the output member 4.

[0116] Regarding the biasing leaf spring 40, the first direction and the second direction refer to the first direction and the second direction of the engaging element 5 when it is disposed between the output side engaging portion 17 and the output side engaged portion .

[0117] The shape of the biasing plate spring 40 is not limited as long as it is configured to have a pair of support plate portions 45 and pressed plate portions 43. The axial positions and number of pressed plate portions 43 relative to the engaging element 5 are arbitrary, but in this example, the pressed plate portion 43 is configured by a pair of pressed plate portions 43 arranged in portions offset on both axial sides from the engaging element 5. The pair of pressed plate portions 43 are arranged in positions overlapping the pair of output-side pressing portions 23 in the first direction.

[0118] In this example, the pair of support plate portions 45 constitute both end portions in the second direction of the biasing leaf spring 40. Each of the support plate portions 45 constituting the pair of support plate portions 45 may have an engaging portion for axially positioning the biasing leaf spring 40 with respect to the engaging element 5, such as a notch for engaging the protrusion 39 or a through hole for inserting the protrusion 39, or may not have such an engaging portion. In this example, each of the support plate portions 45 constituting the pair of support plate portions 45 does not have such an engaging portion and has a rectangular planar shape when viewed from the first direction, which is the plate thickness direction.

[0119] In this example, the pair of pressed plate portions 43 constitute an intermediate portion in the second direction of the biasing plate spring 40. Each pressed plate portion 43 constituting the pair of pressed plate portions 43 connects the ends on both axial sides of the base ends, which are the ends of the pair of support plate portions 45 that are closer to each other in the second direction.

[0120] In this example, each pressed plate portion 43 has an intermediate plate portion 46 that forms an intermediate portion in the second direction, and a pair of end plate portions 47 that form opposite end portions in the second direction. The intermediate plate portion 46 has a band-like planar shape that extends in the second direction when viewed from the first direction, which is the plate thickness direction. Each end plate portion 47 that forms the pair of end plate portions 47 bends at an obtuse angle from the opposite end portions in the second direction of the intermediate plate portion 46 toward a side away from the pressed surface 6 in the first direction, extends in a direction away from the pressed surface 6 in the first direction as it extends away from the intermediate plate portion 46 in the second direction, and has a tip portion connected to the axial end portion of the base end portion of the pair of support plate portions 45.

[0121] The distance between the distal ends of the pair of support plate portions 45 on the far side in the second direction, i.e., the length of the biasing plate spring 40 in the second direction, is slightly smaller than the distance between the proximal ends of the two protrusions 39 of the engaging element 5. The distance between the proximal ends of the pair of pressed plate portions 43 on the axial direction is slightly larger than the axial thickness of the engaging element 5.

[0122] The biasing leaf spring 40 is positioned between the two protrusions 39 of the engaging element 5 in the second direction, thereby restricting displacement in the second direction relative to the engaging element 5; the axial middle portions of the pair of support plate portions 45 engage, specifically contact, with the output side engaged portions 36 of the engaging element 5, thereby restricting displacement in the first direction toward the pressed surface 6 relative to the engaging element 5; and the pair of pressed plate portions 43 are positioned in positions that sandwich the engaging element 5 from both axial sides, thereby assembling the biasing leaf spring 40 to the engaging element 5 in a state in which axial displacement relative to the engaging element 5 is restricted.

[0123] Furthermore, the biasing leaf spring 40 is elastically deformed such that the intermediate plate portions 46 constituting each pressed plate portion 43 are pressed by the pair of output-side pressing portions 23, and the pair of support plate portions 45 elastically press the output-side engaged portions 36. As a result, the biasing leaf spring 40 elastically biases the engaging element 5 in a direction that brings the pressing surface 34 closer to the pressed surface 6 in the first direction.

[0124] In the reverse input cutoff clutch 1 of this example, the pair of output-side pressing portions 23 provided on the output member 4 are disposed at central positions in the second direction. For this reason, in a neutral state in which no rotational torque is input to the input member 3 and the longitudinal direction (longitudinal direction) of the output-side engaging portion 17 and the radially inner surface of the engaging element 5 are disposed parallel to each other, and in a state in which rotational torque is input to the input member 3 and the engaging element 5 moves to a position farthest from the pressed surface 6 in the first direction and the longitudinal direction (longitudinal direction) of the output-side engaging portion 17 and the radially inner surface of the engaging element 5 are disposed parallel to each other (torque transmittable state), the pair of output-side pressing portions 23 press central portions in the second direction (portions P in FIG. 4 ) of the pair of pressed plate portions 43 in the first direction. Therefore, in the neutral state and the torque transmission state, the pair of support plate portions 45 arranged at a distance in the second direction press both side portions of the engaging member 5 in the second direction (portion Q in Figure 4) with equal force in the first direction.

[0125] Furthermore, even when a rotational torque is input reversely to the output member 4 from the neutral state or the torque transmittable state, causing the output member 4 to rotate in either direction, the inclined surface portions 26 of the tip surfaces 44 of the pair of restricting portions 18a, 18b, which are located on both sides of the output-side pressing portion 23 in the second direction, do not come into contact with the pair of pressed plate portions 43, and therefore the output member 4 presses only the central portions in the second direction of the pair of pressed plate portions 43 (portions P in FIG. 4) in the first direction via the pair of output-side pressing portions 23. Therefore, even when the output member 4 rotates in either direction, the pair of support plate portions 45, which are arranged spaced apart in the second direction, press both side portions in the second direction of the engaging element 5 (portions Q in FIG. 4) with equal force in the first direction.

[0126] That is, the structure of this example can effectively prevent a moment load from acting on the engaging member 5 from the biasing leaf spring 40 not only in the neutral state and the torque transmittable state, but also when the output member 4 rotates in either direction. Therefore, when a rotational torque is reversely input to the output member 4 from the torque transmittable state, the posture of the engaging member 5 is stabilized as the engaging member 5 moves in a direction approaching the pressed surface 6 in the first direction, and the state can be appropriately transitioned to the locked state or the semi-locked state.

[0127] Furthermore, in this example, each of the pair of output side pressing portions 23 is configured by a partial cylindrical surface centered on the central rotation axis O of the output member 4. Therefore, even when the output member 4 rotates in either direction, the positions at which the pair of output side pressing portions 23 press the pair of pressed plate portions 43 hardly move in the second direction.

[0128] Furthermore, the distance L in the first direction from the rotation center axis O of the output member 4 to the portion of the output-side pressing portion 23 that presses the pressed plate portion 43 is equal to the magnitude L1 in the neutral state or the torque-transmittable state shown in Fig. 9(a) and the magnitude L2 in the locked state or semi-locked state shown in Fig. 9(b) (L1 = L2). Therefore, the amount of pressing of the pressed plate portion 43 in the first direction by the output-side pressing portion 23 does not change as the output member 4 rotates from the neutral state or the torque-transmittable state to the locked state or semi-locked state.

[0129] The number of biasing leaf springs 40 is determined according to the number of engaging elements 5, and when the engaging elements 5 are made up of a plurality of engaging elements 5, the biasing leaf springs 40 are also made up of a plurality of biasing leaf springs 40.

[0130] In this example, the biasing leaf spring 40 is configured by two biasing leaf springs 40 that are arranged between the two engaging elements 5 and the output member 4, respectively, in accordance with the number of engaging elements 5.

[0131] <Explanation of reverse input cutoff clutch operation> The operation of the reverse input cutoff clutch 1 of this example will be described with reference to Figures 6 and 7. Figures 6 and 7 omit the illustration of the two biasing leaf springs 40, and exaggerate the radial gaps between the input member 3 and the output member 4 and the two engaging elements 5.

[0132] In the reverse input cutoff clutch 1 of this example, when a rotational torque is input to the input member 3, the engaging element 5 moves in a direction away from the pressed surface 6, regardless of the rotational direction of the input member 3. Then, the rotational torque input to the input member 3 is transmitted to the output member 4 via the engaging element 5.

[0133] That is, when a rotational torque is input to the input member 3, the input-side engaging portion 13 rotates inside the input-side engaged portion 35 in the rotation direction of the input member 3 (counterclockwise in the example of FIG. 6), as shown in FIG. 6. This reduces the gap between the radially inner surface 15 of the input-side engaging portion 13 and the radially inner surface 37 of the input-side engaged portion 35, and brings the radially inner surface 15 of the input-side engaging portion 13 into contact with the radially inner surface 37 of the input-side engaged portion 35.

[0134] When the input member 3 rotates further from this state, the radially inner surface 15 of the input-side engaging portion 13 presses the radially inner surface 37 of the input-side engaged portion 35 radially inward, and the engaging element 5 moves in a direction away from the pressed surface 6 against the elastic biasing force of the biasing leaf spring 40, i.e., while elastically deforming the biasing spring 40. In other words, the engaging element 5 moves radially inward based on its engagement with the input member 3, and the output-side engaged portion 36 of the engaging element 5 engages with the output-side engaging portion 17 of the output member 4. In this example, the radially inner surfaces of the two engaging elements 5 approach each other, and the output-side engaged portions 36 of the two engaging elements 5 clamp the output-side engaging portion 17 of the output member 4 from both radial sides.

[0135] More specifically, when the output-side engaged portion 36 of the engaging element 5 and the output-side engaging portion 17 engage with each other, the output member 4 rotates so that the intermediate portion in the longitudinal direction of the side surface 24 of the output-side engaging portion 17 is parallel to the output-side engaged portion 36 of the engaging element 5, causing the intermediate portion to abut against the output-side engaged portion 36 without any rattle. As a result, the rotational torque input to the input member 3 is transmitted to the output member 4 via the engaging element 5 and is output from the output member 4.

[0136] When a rotational torque is reversely input to the output member 4, the engaging element 5 moves in a direction approaching the pressed surface 6, regardless of the rotational direction of the output member 4. Then, the rotational torque reversely input to the output member 4 is either completely blocked and not transmitted to the input member 3, or only a portion of the rotational torque reversely input to the output member 4 is transmitted to the input member 3, with the remainder blocked.

[0137] 7, the output-side engaging portion 17 rotates relative to the engaging element 5 in the rotation direction of the output member 4 (clockwise in the example of FIG. 7). The output-side engaged portion 36 is pressed radially outward by a portion of the outer peripheral surface of the output-side engaging portion 17 that is closer to the end of the side surface 24 in the longitudinal direction, and the engaging element 5 moves in a direction approaching the pressed surface 6.

[0138] That is, the engaging elements 5 move radially outward based on their engagement with the output member 4, and the pressing surfaces 34 of the engaging elements 5 come into contact with the pressed surface 6 and frictionally engage with the pressed surface 6. In this example, the two engaging elements 5 move radially outward, i.e., in directions away from each other, based on their engagement with the output member 4, and the pressing surfaces 34 of the two engaging elements 5 come into contact with the pressed surface 6 and frictionally engage with the pressed surface 6.

[0139] As a result, the rotational torque input back to the output member 4 is either completely blocked and not transmitted to the input member 3, or only a portion of the rotational torque input back to the output member 4 is transmitted to the input member 3 and the remainder is blocked.

[0140] To completely block the rotational torque input in reverse to the output member 4 and prevent it from being transmitted to the input member 3, the engaging element 5 is clamped between the output side engaging portion 17 and the pressed member 2 so that the pressing surface 34 of the engaging element 5 does not slide against the pressed surface 6, thereby locking the output member 4.

[0141] In order to transmit only a portion of the rotational torque input inversely to the output member 4 to the input member 3 and block the remainder, the engaging element 5 is clamped between the output side engaging portion 17 and the pressed member 2 so that the pressing surface 34 of the engaging element 5 slides against the pressed surface 6, thereby semi-locking the output member 4.

[0142] In the reverse input cutoff clutch 1 of this example, the size of the gap between each component is adjusted to enable the above operation. In particular, when the pressing surface 34 of the engaging element 5 is in contact with the pressed surface 6, a gap is set to exist between the radially inner surface 15 of the input side engaging portion 13 and the radially inner surface 37 of the input side engaged portion 35.

[0143] This prevents the input side engaging portion 13 from blocking the radially outward movement of the engaging element 5 when a rotational torque is input in reverse to the output member 4, and even after the pressing surface 34 comes into contact with the pressed surface 6, the surface pressure acting on the contact point between the pressing surface 34 and the pressed surface 6 changes depending on the magnitude of the rotational torque input in reverse to the output member 4, ensuring that the output member 4 is locked or semi-locked appropriately.

[0144] In the reverse input cutoff clutch 1 of this example, the biasing leaf spring 40 elastically biases the engagement element 5 in a direction approaching the pressed surface 6. This allows the two pressing surfaces 34 of the engagement element 5 to be kept in contact with the pressed surface 6 except when rotational torque is input to the input member 3. Therefore, when rotational torque is reversely input to the output member 4, the surface pressure at the contact points between the two pressing surfaces 34 of the engagement element 5 and the pressed surface 6 can be quickly increased, and the reverse input cutoff clutch 1 can be switched to a locked or semi-locked state. In short, the reverse input cutoff clutch 1 of this example can ensure good locking performance.

[0145] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIGS. 10(a) and 10(b).

[0146] In this example, each output-side pressing portion 23a provided in the output member 4a is parallel to the rotation center axis O of the output member 4a and is formed by a partial cylindrical surface having a radius of curvature R2 centered on an axis Oa that is displaced to the side farther from the output-side pressing portion 23a than the rotation center axis O. That is, in this example, the radius of curvature R2 of the output-side pressing portion 23a is larger than the radius of curvature R1 of the output-side pressing portion 23 in the first example (R2 > R1).

[0147] In this example, since the center axis Oa of curvature of the output-side pressing portion 23a is displaced from the rotation center axis O of the output member 4a, as the output member 4a rotates from the neutral state or the torque-transmissible state to the locked state or the semi-locked state, the pressing position of the pressed plate portion 43 (see FIG. 4) by the output-side pressing portion 23a moves slightly in the second direction.

[0148] When implementing the present disclosure, as in this example, when the radius of curvature R2 of the output-side pressing portion 23a is made larger than the radius of curvature R1 of the output-side pressing portion 23 in the first example, the radius of curvature R2 of the output-side pressing portion 23a can be set, for example, to a value not more than 5 times the radius of curvature R1 of the output-side pressing portion 23 in the first example. In this example, the radius of curvature R2 of the output-side pressing portion 23a is set to a value about 3 times the radius of curvature R1 of the output-side pressing portion 23 in the first example.

[0149] Also, in this example, the distance L in the first direction from the rotation center axis O of the output member 4a to the portion of the output-side pressing portion 23a that presses the pressed plate portion 43 (see FIG. 4) is slightly larger in the locked state or semi-locked state shown in FIG. 10(b) than in the neutral state or torque-transmissible state shown in FIG. 10(a) (L1 < L2). For this reason, as the output member 4a rotates from the neutral state or the torque-transmissible state to the locked state or the semi-locked state, the pressing amount in the first direction of the pressed plate portion 43 by the output-side pressing portion 23a becomes slightly larger. Therefore, the biasing force of the engaging member 5 (see FIG. 4) by the biasing plate spring 40 (see FIG. 4) in the locked state or semi-locked state can be improved by that amount, and the locked state or semi-locked state can be stabilized.

[0150] The other configurations and effects of the second example are the same as those of the first example.

[0151] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIGS. 11(a) and 11(b).

[0152] In this example, each output-side pressing portion 23b provided on the output member 4b is configured by a partial cylindrical surface with a radius of curvature R3, which is parallel to the rotation center axis O of the output member 4b and has a center on an axis Ob that is shifted from the rotation center axis O to the side closer to the output-side pressing portion 23a. That is, in this example, the radius of curvature R3 of the output-side pressing portion 23b is smaller than the radius of curvature R1 of the output-side pressing portion 23a in the first example (R3 <R1)。

[0153] In this example, the curvature center axis Ob of the output side pressing portion 23b is offset from the rotation center axis O of the output member 4b, and therefore, as the output member 4b rotates from the neutral state or the torque transmittable state to the locked state or semi-locked state, the pressing position of the pressed plate portion 43 (see Figure 4) by the output side pressing portion 23b moves slightly in the second direction.

[0154] When implementing the present disclosure, if the radius of curvature R3 of the output-side pressing portion 23b is set smaller than the radius of curvature R1 of the output-side pressing portion 23 in the first example, as in this example, the radius of curvature R3 of the output-side pressing portion 23b can be set to, for example, a value that is 0.1 times or more the radius of curvature R1 of the output-side pressing portion 23 in the first example. In this example, the radius of curvature R3 of the output-side pressing portion 23b is set to a value that is approximately 0.2 times the radius of curvature R1 of the output-side pressing portion 23 in the first example.

[0155] In this example, the distance L in the first direction from the rotation center axis O of the output member 4b to the portion of the output-side pressing portion 23b that presses the pressed plate portion 43 (see FIG. 4) is L3 in the locked state or semi-locked state shown in FIG. 11(b) which is slightly smaller than L1 in the neutral state or the torque-transmittable state shown in FIG. 11(a) (L1>L3). Therefore, as the output member 4b rotates from the neutral state or the torque-transmittable state to the locked state or the semi-locked state, the amount of pressing of the pressed plate portion 43 in the first direction by the output-side pressing portion 23b becomes smaller, although only slightly.

[0156] The other configurations and effects of the third example are the same as those of the first example.

[0157] [Example 4] A fourth example of the embodiment of the present disclosure will be described with reference to FIGS. 12 to 14b(b).

[0158] In this example, the output member 4c includes a main body portion 48 including the output-side engaging portion 17, and a pair of regulating parts 49 coupled and fixed to the main body portion 48. The pair of regulating parts 18c, 18d is constituted by the pair of regulating parts 49.

[0159] The pair of regulating parts 49 can be connected and fixed to the main body 48 by any appropriate method, such as press-fitting, screwing, threading, adhesive, welding, etc. In this example, the connecting and fixing method is to press-fit engaging protrusions 51 provided on each regulating part 49 into engaging holes 50 provided in the main body 48.

[0160] In this example, the main body portion 48 has an output shaft portion 20, an intermediate shaft portion 19a that protrudes toward one axial side from the center of the end face 41 on one axial side of the output shaft portion 20 and has an output side engagement portion 17 in the middle of the axial direction, and a small diameter shaft portion 21 that protrudes toward one axial side from the center of the end face 41 on one axial side of the intermediate shaft portion 19a, and the entire body is constructed as a single unit.

[0161] In this example, when the intermediate shaft portion 19a is cut along an imaginary plane perpendicular to the central axis of rotation of the output member 4c, the portions of the intermediate shaft portion 19a located on both axial sides of the output side engaging portion 17 have the same cross-sectional shape as the output side engaging portion 17, except that they are provided with engaging holes 50.

[0162] The intermediate shaft portion 19a has an engagement hole 50 penetrating in the short direction (short axis direction) at the center in the longitudinal direction (long axis direction) of portions located on both axial sides of the output side engagement portion 17. The engagement hole 50 is configured as a circular hole. Note that the engagement hole 50 may also be configured as a bottomed hole instead of a through hole.

[0163] Each of the pair of restricting parts 49 has restricting portions 18c, 18d and an engaging protrusion 51.

[0164] The restricting portions 18c, 18d have a generally arched shape when viewed in the axial direction. The middle portion of the radially outer surface of the restricting portions 18c, 18d in the second direction is formed by the output-side pressing portion 23, and both side portions of the radially outer surface of the restricting portions 18c, 18d in the second direction are formed by inclined surface portions 26. The radially inner surface of the restricting portions 18c, 18d is formed by a flat surface.

[0165] The engaging protrusions 51 protrude radially inward from the center of the radially inner surfaces of the restricting portions 18c, 18d, and have a cylindrical shape.

[0166] Each regulating part 49 is connected and fixed to the main body portion 48 by pressing the engaging protrusion 51 into the engaging hole 50 of the intermediate shaft portion 19a and abutting the radial inner surfaces of the regulating portions 18c, 18d against the short-side side surfaces of the intermediate shaft portion 19a.

[0167] The number of pairs of regulating parts 49 is determined according to the number of pairs of regulating portions 18c, 18d provided on the output member 4c, and if the pairs of regulating portions 18c, 18d are composed of multiple sets of pairs of regulating portions 18c, 18d, the pairs of regulating parts 49 are also composed of multiple sets of pairs of regulating parts 49.

[0168] In this example, the pair of regulating parts 49 is configured by two pairs of regulating parts 49, which corresponds to the number of pairs of regulating portions 18c, 18d provided on the output member 4c.

[0169] The other configurations and effects of the third example are the same as those of the first example.

[0170] The reverse input cutoff clutch of the present disclosure can be implemented by appropriately combining the structures of the above-described embodiments within the scope of no contradiction. [Explanation of symbols]

[0171] 1 Reverse input cutoff clutch 2. Pressurized member 3 Input member 4, 4a, 4b, 4c Output member 5 Engagement element 6 Pressed surface 7 Output element 8 Large diameter cylindrical surface 9 Small diameter cylindrical surface part 10 Connection surface 11 Inward flange 12 screw holes 13 Input side engagement portion 14 Input shaft 15 Radial inner surface 16 Radial outer surface 17 Output side engagement portion 18a, 18b, 18c, 18d Regulatory Department 19, 19a Intermediate shaft part 20 Output shaft 21 Small diameter shaft 22 Output flange 23, 23a, 23b Output side pressing portion 24 Side 25 End face 26 Slope section 27a, 27b Regulatory aspects 28 Radial Rolling Bearing 29 Outer ring 30 Inner Circle 31 Rolling elements 32a, 32b retaining ring 33 Plain bearings 34 Pressing surface 35 Input side engaged portion 36 Output side engaged part 37 Radial inner surface 38 Flat surface section 39 Convex part 40 biasing leaf spring 41 End face 42 Corner R 43 Pressed plate part 44 Tip surface 45 Support plate part 46 Intermediate plate 47 End plate 48 Main body part 49 Regulated Parts 50 engagement hole 51 Engagement protrusion 100 biased leaf spring 101 Engagement element 102 Support plate part 103 Pressed plate part 104 Output member 105 Output side pressing part

Claims

1. a pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion disposed radially inside the pressed surface and disposed coaxially with the pressed surface; an output member having an output side engaging portion disposed radially inward of the input side engaging portion and disposed coaxially with the pressed surface; an engaging element having a pressing surface facing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and arranged to be movable in a first direction which is a direction in which the pressing surface approaches or moves away from the pressed surface; a biasing leaf spring that is elastically sandwiched between the output member and the engaging element and that elastically biases the engaging element in a direction that brings it closer to the pressed surface; Equipped with When a rotational torque is input to the input member, the input side engaging portion engages with the input side engaged portion, and the engaging element moves in a direction away from the pressed surface in the first direction, thereby engaging the output side engaged portion with the output side engaging portion, thereby transmitting the rotational torque input to the input member to the output member. Conversely, when a rotational torque is input in the reverse direction to the output member, the output side engaging portion engages with the output side engaged portion, and the pressing surface is pressed against the pressed surface, causing the pressing surface to frictionally engage with the pressed surface. the biasing leaf spring is disposed so as to be spaced apart in a second direction perpendicular to both the axial direction and the first direction, and includes a pair of support plate portions that engage with the engaging elements, and a pressed plate portion that connects the pair of support plate portions to each other; the output member has an output-side pressing portion at a central position in the second direction that presses the pressed plate portion toward a side closer to the pressed surface in the first direction. Reverse input cut-off clutch.

2. 2. The reverse input cutoff clutch according to claim 1, wherein the output side pressing portion is formed by a partial cylindrical surface having a center on the rotational axis of the output member or an axis parallel to the rotational axis.

3. The pressed plate portion is composed of a pair of pressed plate portions disposed at positions offset from the engaging element on both sides in the axial direction, The output-side pressing portion is configured by a pair of output-side pressing portions arranged at positions overlapping the pair of pressed plate portions in the first direction.

2. The reverse input disconnecting clutch according to claim 1.

4. the output member has a pair of regulating portions that protrude from portions adjacent to both axial sides of the output-side engaging portion toward a side closer to the pressed surface in the first direction and are positioned to sandwich the engaging element from both axial sides, and the pair of regulating portions regulate axial movement of the engaging element relative to the output member, The pair of output-side pressing portions are configured by tip surfaces of the pair of restricting portions that face the pressed surface side in the first direction.

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

5. the output member includes a main body portion including the output-side engaging portion, and a pair of restricting components coupled and fixed to the main body portion, The pair of regulating portions is constituted by the pair of regulating parts.

5. The reverse input disconnecting clutch according to claim 4.

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

Images