Reverse input blocking clutch

Abstract

This invention provides a reverse input blocking clutch structure that reduces the number of parts and prevents stress concentration in the output component. [Solution] The output side engaging portion 19 of the output member 4 has an output side engaging surface 21 on its outer circumferential surface that engages with the output side engaged portion 46. The output shaft portion 20 has a groove portion 26 that extends linearly in a direction perpendicular to a second virtual plane that includes the central axis of the output member 4, and perpendicular to a first virtual plane that includes the ends on both sides of the output side engaging surface 21 in the axial direction, in a portion of the outer circumferential surface where the phase in the circumferential direction coincides with the output side engaging surface 21. The groove shape of the cross-section of the groove portion 26 with respect to the second virtual plane is approximately U-shaped or approximately C-shaped.

Description

Technical Field

[0001] The present disclosure relates to a reverse input blocking clutch that transmits the rotational torque input to an input member to an output member, while completely blocking the rotational torque reversely input to the output member from being transmitted to the input member, or transmitting only a part of it to the input member and blocking the rest.

Background Art

[0002] A reverse input blocking clutch transmits the rotational torque input to an input member connected to an input side mechanism such as a drive source to an output member connected to an output side mechanism such as a speed reduction mechanism, while completely blocking the rotational torque reversely input to the output member from being transmitted to the input member, or transmitting only a part of it to the input member and blocking the rest.

[0003]

[0004] Depending on the difference in the mechanism for blocking the rotational torque reversely input to the output member, the reverse input blocking clutch includes a lock-type reverse input blocking clutch provided with a mechanism for preventing the rotation of the output member when the rotational torque is reversely input to the output member, and a free-type reverse input blocking clutch provided with a mechanism for idling the output member when the rotational torque is input to the output member. Which of the lock-type reverse input blocking clutch and the free-type reverse input blocking clutch to use is appropriately determined according to the use of the device incorporating the reverse input blocking clutch and the like.In the lock-type reverse input blocking clutch described in International Publication No. 2023 / 136149, when rotational torque is input to an input member, the input-side engaging portion of the input member engages with the input-side engaged portion of the engaging element, causing the engaging element to move away from the pressed surface provided on the pressed member, and the output-side engaged portion of the engaging element engages with the output-side engaging portion of the output member, thereby transmitting the rotational torque input to the input member to the output member. On the other hand, when rotational torque is input in reverse to the output member, the output-side engaging portion of the output member engages with the output-side engaged portion of the engaging element, causing the engaging element to move towards the pressed surface, pressing the pressing surface against the pressed surface and frictionally engaging the pressing surface with the pressed surface. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2023 / 136149 brochure [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In a reverse input blocking clutch, if the axial movement of the engaging element relative to the output member is not restricted, the engaging element may tilt axially. If the engaging element remains tilted axially and moves radially outward, the pressing surface and the pressed surface may come into local contact, causing jamming. This can unnecessarily increase the force required to switch from a locked or semi-locked state to an unlocked or semi-unlocked state, or cause plastic deformation or wear on the pressing surface and / or the pressed surface.

[0007] Therefore, in the reverse input blocking clutch described in International Publication No. 2023 / 136149, the axial movement of the engaging element relative to the output member is restricted by using two spacers and a retaining ring which acts as a stopper member. Specifically, a spacer is placed between the retaining ring, which is locked to the end of the output member, and the engaging element, and another spacer is placed between the surface of the engaging element opposite to the surface facing the retaining ring and the axial end face of the output shaft portion of the output member, which is located axially adjacent to the output-side engaging portion of the output member, thereby restricting the axial movement of the engaging element relative to the output member.

[0008] The reverse input shutoff clutch described in International Publication No. 2023 / 136149 requires spacers on both the axial sides of the engaging element, resulting in an increased number of parts, higher parts management costs, and increased assembly man-hours.

[0009] In order to omit the spacer positioned between the engaging element and the axial end face of the output shaft, one of the two spacers incorporated into the reverse input blocking clutch, it is conceivable to directly restrict the axial movement of the engaging element using the axial end face of the output shaft.

[0010] However, to prevent stress concentration, a corner R portion with a large radius of curvature is provided at the connection between the axial end face of the output shaft and the output-side engaging surface of the output-side engaging portion that engages with the output-side engaged portion of the engaging element.

[0011] Therefore, if the axial movement of the engaging element is to be directly restricted by the axial end face of the output shaft, the corner radius and the engaging element will interfere with each other, making it difficult to properly restrict the axial movement of the engaging element. Reducing the radius of curvature of the corner radius can properly restrict the axial movement of the engaging element, but simply reducing the radius of curvature of the corner radius can cause stress to concentrate in the corner radius, potentially leading to damage to the corner radius.

[0012] This disclosure aims to realize a reverse input blocking clutch structure that can reduce the number of parts and prevent stress concentration in the output member. [Means for solving the problem]

[0013] A reverse input blocking clutch according to one aspect of the present disclosure comprises a pressed member, an input member, an output member, and an engaging element.

[0014] The member to be pressed has a surface to be pressed on its inner circumferential surface.

[0015] The input member has an input-side engaging portion located radially inward of the pressed surface, is connected to an input-side mechanism on one axial side, and is arranged coaxially with the pressed surface.

[0016] The output member has an output-side engaging portion that is positioned radially inward from the input-side engaging portion, is connected to the output-side mechanism on the other axial side, and is positioned coaxially with the pressed surface.

[0017] The engaging element has a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and is arranged to be movable in the radial direction.

[0018] When rotational torque is input to the input member, the engaging element moves radially away from the pressed surface based on the input-side engaging portion engaging with the input-side engaged portion, thereby engaging the output-side engaged portion with the output-side engaging portion and transmitting the rotational torque input to the input member to the output member. Conversely, when rotational torque is input in reverse to the output member, the engaging element presses the pressing surface against the pressed surface based on the output-side engaging portion engaging with the output-side engaged portion, causing the pressing surface to frictionally engage with the pressed surface.

[0019] The output-side engaging portion has an output-side engaging surface on its outer circumferential surface that engages with the output-side engaged portion.

[0020] The output member has an output shaft portion, the output shaft portion having at least a part of which has an axial end face on one side that faces the engaging element in the axial direction.

[0021] The end face on one axial side of the output shaft portion and the output-side engagement surface are connected via a corner radius.

[0022] The output shaft portion has a groove portion that extends linearly in a direction perpendicular to a second virtual plane, which includes the central axis of the output member, and perpendicular to a first virtual plane passing through the ends of the output engagement surface on both sides in the circumferential direction, and perpendicular to a second virtual plane, which includes the central axis of the output member, in the portion of the outer peripheral surface on one side in the axial direction in which the phase with respect to the circumferential direction coincides with the output side engagement surface.

[0023] With respect to the second virtual plane, the groove shape of the cross-section of the groove is approximately U-shaped or approximately C-shaped.

[0024] In a reverse input blocking clutch according to one aspect of the present disclosure, the groove shape of the cross-section of the groove portion may be substantially U-shaped, and the inner surface of the groove portion may consist of a first inner surface that is flat and facing one side in the axial direction, a second inner surface that is flat and facing the other side in the axial direction, and a bottom surface that connects the first inner surface and the second inner surface.

[0025] When the inner surface of the groove is composed of the first inner surface, the second inner surface, and the bottom surface, the bottom surface can be composed of a partially cylindrical concave surface having a single radius of curvature.

[0026] When the inner surface of the groove is composed of the first inner surface, the second inner surface, and the bottom surface, the bottom surface may have a first curved surface portion having a concave arc-shaped cross-section connected to the first inner surface, and a second curved surface portion having a concave arc-shaped cross-section connected to the second inner surface.

[0027] If the bottom surface has a first curved portion and a second curved portion, the bottom surface may have a bottom flat portion positioned substantially parallel to the output-side engagement surface between the first curved portion and the second curved portion in the axial direction.

[0028] If the bottom surface has a first curved portion and a second curved portion, the radius of curvature of the first curved portion can be made larger than the radius of curvature of the second curved portion.

[0029] If the radius of curvature of the first curved surface is made larger than the radius of curvature of the second curved surface, the radius of curvature of the second inner surface can be made to be approximately the same size as the radius of curvature of the corner R portion.

[0030] In a reverse input blocking clutch according to one aspect of the present disclosure, the radial distance from the central axis of the output member to the groove can be set to a size of 0.85 times or more and 1.25 times or less the radial distance from the central axis of the output member to the output-side engagement surface.

[0031] In a reverse input blocking clutch according to one aspect of the present disclosure, the axial groove width at the opening of the groove can be made larger than the axial dimension from the end face on one axial side of the output shaft to the opening of the groove.

[0032] In a reverse input shutoff clutch according to one aspect of the present disclosure, the output-side engagement surface may consist of two output-side engagement surfaces arranged parallel to each other, and the groove may consist of two grooves arranged on opposite sides in the diameter direction of the outer circumferential surface of the output shaft.

[0033] In a reverse input blocking clutch according to one aspect of the present disclosure, a minute axial gap can be provided between the axial end face of the output shaft portion on one side and the axial end face of the engaging element on the other side. [Effects of the Invention]

[0034] According to one embodiment of the reverse input blocking clutch of this disclosure, the number of parts can be reduced and stress concentration in the output member can be prevented. [Brief explanation of the drawing]

[0035] [Figure 1] Figure 1 is a cross-sectional view of a reverse input interruption clutch, a first example of an embodiment of the present disclosure. [Figure 2] Figure 2 is a magnified view of a portion of Figure 1. [Figure 3] Figure 3 is a perspective view showing one axial side portion of the first example of a reverse input blocking clutch, with one engaging element, pressed member, and input member omitted. [Figure 4] Figure 4 is a cross-sectional view showing the output member removed from the reverse input blocking clutch of the first example. [Figure 5] Figure 5 is a magnified view of a portion of Figure 4. [Figure 6] Figure 6 is a cross-sectional view of section II in Figure 1. [Figure 7] Figure 7 is a cross-sectional view II of Figure 1, showing the state in which rotational torque is applied to the input member, with the biasing member omitted. [Figure 8] Figure 8 is a cross-sectional view II of Figure 1, showing the state in which rotational torque is input to the output member, with the biasing member omitted. [Figure 9] Figure 9 is a graph showing the relationship between the ratio of the radial distance D26 to the radial distance D21 and the magnitude of the maximum torque that can be applied without causing plastic deformation in the corner radius 25. [Figure 10] Figure 10 is a diagram corresponding to Figure 5, showing a reverse input interruption clutch of a second example of an embodiment of the present disclosure. [Figure 11] Figure 11 is a graph showing the relationship between the ratio of the radius of curvature R33 of the second curved surface 33 to the radius of curvature R25 of the corner radius 25 and the magnitude of the maximum shear stress acting on the corner radius 25. [Figure 12] Figure 12 is a diagram corresponding to Figure 5, showing a reverse input interruption clutch of a third embodiment of the present disclosure. [Figure 13] Figures 13(A) to 13(E) are cross-sectional views showing the output components used in the simulation. Figure 13(A) shows Example 1, Figure 13(B) shows Example 2, Figure 13(C) shows Example 3, Figure 13(D) shows Comparative Example 1, and Figure 13(E) shows Comparative Example 2. [Modes for carrying out the invention]

[0036] [Example 1] A first example of a reverse input interruption clutch according to the embodiments of this disclosure will be described with reference to Figures 1 to 9.

[0037] In the following description, unless otherwise specified, axial, radial, and circumferential directions refer to the axial, radial, and circumferential directions of the pressed surface 7. The axial, radial, and circumferential directions of the pressed surface 7 coincide with the axial, radial, and circumferential directions of the input member 3, and also coincide with the axial, radial, and circumferential directions of the output member 4. Furthermore, one axial side refers to the input side of the reverse input blocking clutch 1 (the right side in Figures 1, 2, 4, and 5), and the other axial side refers to the output side of the reverse input blocking clutch 1 (the left side in Figures 1, 2, 4, and 5).

[0038] <Explanation of the structure of the reverse input blocking clutch> The reverse input blocking clutch 1 of this disclosure comprises a pressed member 2, an input member 3, an output member 4, and an engaging element 5.

[0039] Of the elements constituting the reverse input blocking clutch 1, the pressed member 2, the input member 3, and the engaging element 5 have the same configuration and function as a conventional reverse input blocking clutch.

[0040] The pressed member 2 has a pressed surface 7 on its inner circumferential surface. The input member 3 has an input-side engaging portion 14 located radially inward of the pressed surface 7 and is arranged coaxially with the pressed surface 7. The output member 4 has an output-side engaging portion 19 located radially inward of the input-side engaging portion 14 and is arranged coaxially with the pressed surface 7. The engaging element 5 has a pressing surface 44 facing the pressed surface 7, an input-side engaged portion 45 that can engage with the input-side engaging portion 14, and an output-side engaged portion 46 that can engage with the output-side engaging portion 19, and is arranged to be movable in the radial direction.

[0041] When rotational torque is input to the input member 3, the engaging element 5 moves radially away from the pressed surface 7 based on the input-side engaging portion 14 engaging with the input-side engaged portion 45, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output-side engaged portion 46 with the output-side engaging portion 19.

[0042] In response, when rotational torque is input in reverse to the output member 4, the engaging element 5, based on the fact that the output-side engaging part 19 engages with the output-side engaged part 46, presses its pressing surface 44 against the pressed surface 7, causing the pressing surface 44 to frictionally engage with the pressed surface 7. In other words, the reverse input blocking clutch 1 either completely blocks the rotational torque that is input in reverse to the output member 4 and does not transmit it to the input member 3, or transmits only a portion of it to the input member 3 and blocks the rest.

[0043] In this specification, the direction of the pressing surface 44 of the engaging element 5 relative to the pressed surface 7 is defined as the first direction (up and down direction in Figures 6 to 8), and the direction perpendicular to both the axial direction of the pressed surface 7 and the first direction is defined as the second direction (left and right direction in Figures 6 to 8). With respect to the engaging element 5, the direction coinciding with the first direction is defined as the radial direction of the engaging element 5 (direction indicated by arrow α in Figure 6), and the direction coinciding with the second direction is defined as the width direction of the engaging element 5 (direction indicated by arrow β in Figure 6).

[0044] The input-side engaging portion 14 of the input member 3 and the output-side engaging portion 19 of the output member 4 are positioned radially inward of the pressed surface 7. With respect to the first direction, the input-side engaging portion 14, input-side engaged portion 45, output-side engaged portion 46, and output-side engaging portion 19 are arranged in that order radially inward of the pressed surface 7. Furthermore, the input-side engaging portion 14, the output-side engaging portion 19, and the engaging element 5 are rotatable radially inward of the pressed surface 7.

[0045] In particular, the reverse input blocking clutch 1 of this disclosure is characterized by an improved output member 4, which allows the axial movement of the engaging element 5 to be directly restricted by the output member 4 without causing stress concentration in the output member 4. The components of the reverse input blocking clutch 1 will be described below, focusing on the configuration of the output member 4.

[0046] [Subjected component] The pressed member 2 has a pressed surface 7 on its inner circumferential surface. The pressed surface 7 constitutes a surface that contacts the pressing surface 44 of the engaging element 5 when the engaging element 5 moves radially outward in a direction approaching the pressed surface 7 with respect to the first direction. In other words, the pressed surface 7 has the function of frictionally engaging with the pressing surface 44 of the engaging element 5 when rotational torque is input in reverse to the output member 4.

[0047] The pressed member 2 is supported by a fixed portion that does not rotate even when the reverse input blocking clutch 1 is in use, or is integrally provided with the fixed portion so that its rotation is restrained.

[0048] The shape of the pressed member 2 is not limited, as long as it is configured to have a pressed surface 7 on its inner circumferential surface. The pressed surface 7 is circular when viewed from the axial direction, but is not limited to this; however, in this example, it is cylindrical in shape with no change in inner diameter with respect to the axial direction.

[0049] In this example, the pressed member 2 includes a housing element 8. The housing element 8 is an element for incorporating the pressed member 2 into a mechanical element to which the reverse input blocking clutch 1 is applied.

[0050] The housing element 8 has a stepped cylindrical inner surface. Specifically, the inner surface of the housing element 8 is formed by connecting a large-diameter cylindrical surface portion 9 on one axial side and a small-diameter cylindrical surface portion 10 on the other axial side with a connecting surface portion 11 facing one axial side. In this example, the large-diameter cylindrical surface portion 9 constitutes the pressed surface 7.

[0051] The housing element 8 has an inwardly projecting flange portion 12 at one axial end of the small-diameter cylindrical surface portion 10, and has screw holes 13 opening at multiple locations in the circumferential direction on the other axial side surface.

[0052] The pressed member 2 may also include another housing element that closes the opening on one axial side of the housing element 8. In this case, the pressed member 2 is constructed by fitting the other housing element to the axial end of the housing element 8 without any play (spigot fitting), thereby positioning the housing element 8 and the other housing element radially, and then connecting the housing element 8 and the other housing element with a connecting member such as a bolt.

[0053] [Input components] The input member 3 has an input-side engaging portion 14 located radially inward of the pressed surface 7 and is arranged coaxially with the pressed surface 7.

[0054] The input member 3 is connected to an input-side mechanism such as an electric motor on one axial side, and rotational torque is input to it. Specifically, the input member 3 is composed of the output shaft of the input-side mechanism, or it is composed as a separate member from the output shaft and can be fixed coaxially to the output shaft.

[0055] The input-side engaging portion 14 is provided on a part of the input member 3 that is radially outward from the rotational axis, and has a portion that engages, specifically contacts, with the input-side engaged portion 45 of the engaging element 5. The input-side engaging portion 14 is configured to engage (contact) its radially inner surface 16 with the radially inner surface 47 of the input-side engaged portion 45 as the input member 3 or engaging element 5 rotates.

[0056] In this example, the input member 3 has an input shaft portion 15 and an input flange portion 17, in addition to the input-side engaging portion 14.

[0057] The input shaft portion 15 is an element for connecting the input-side mechanism and the input member 3 to enable the transmission of rotational torque. In this example, the input shaft portion 15 has a cylindrical shape. The input member 3 is connected to the output shaft of the input-side mechanism, such as an electric motor, in a torque-transmitting manner by, for example, a non-circular engagement such as a spline engagement between the inner circumferential surface of the input shaft portion 15 and the outer circumferential surface of the output shaft of the input-side mechanism, or by press-fitting or the like.

[0058] The input flange portion 17 is an element for positioning the input-side engaging portion 14 at a location radially outward from the rotation center of the input member 3. In this example, the input flange portion 17 protrudes radially outward from the outer circumferential surface of the other axial end of the input shaft portion 15 over its entire circumference.

[0059] The input-side engaging portion 14 is an element that, when rotational torque is applied to the input member 3, engages with the input-side engaged portion 45 of the engaging element 5, causing the engaging element 5 to rotate in the same direction as the input torque. In this example, the input-side engaging portion 14 protrudes axially toward the other side from a portion of the other axial side of the input flange portion 17 that is radially outward from the center of rotation.

[0060] The shape of the input-side engaging portion 14 is not limited, as long as it is configured to engage with the input-side engaged portion 45 of the engaging element 5.

[0061] For example, the input-side engaging portion 14 may have an end face shape that is symmetrical with respect to the circumferential direction, or it may have an end face shape that is asymmetrical with respect to the circumferential direction. In this example, the input-side engaging portion 14 has an end face shape that is symmetrical with respect to the circumferential direction.

[0062] For example, the input-side engaging portion 14 can have a partially annular shape, a substantially trapezoidal shape, or a similar end face shape, where the length in the second direction increases as it moves outward in the first direction when viewed from the axial direction. In this example, the input-side engaging portion 14 has an end face shape similar to a substantially trapezoidal shape, and of the radially inner surface 16 of the input-side engaging portion 14, the intermediate portion in the second direction is composed of a flat surface perpendicular to the line connecting the central axis O of the input member 3 and the center of the input-side engaging portion 14 when viewed from the axial direction, and the portions on both sides in the second direction are composed of partially cylindrical convex surfaces that are inclined in the direction outward in the first direction as they move toward both sides in the second direction. The radially outer surface 18 of the input-side engaging portion 14 is composed of a partially cylindrical convex surface centered on the central axis O.

[0063] The number of input-side engaging portions 14 is determined according to the number of engaging elements 5. If the engaging element 5 is composed of multiple engaging elements 5, the input-side engaging portions 14 are also composed of multiple input-side engaging portions 14.

[0064] In this example, the engaging element 5 is composed of two engaging elements 5. Therefore, the input-side engaging portion 14 is composed of two input-side engaging portions 14, corresponding to the number of engaging elements 5. The two input-side engaging portions 14 are positioned at two radially opposite locations on the other axial side of the input flange portion 17, and are spaced apart from each other with respect to the radial direction of the input member 3.

[0065] The input member 3 can be rotatably supported by the pressed member 2 or the other housing element.

[0066] [Output components] The output member 4 has an output-side engaging portion 19 that is located radially inward from the input-side engaging portion 14, and is arranged coaxially with the pressed surface 7. In other words, the output member 4 is also arranged coaxially with the input member 3.

[0067] The output member 4 is connected to an output mechanism, such as a reduction gear, on the other axial side, and is configured to output rotational torque to the output mechanism as it rotates. Specifically, the output member 4 can be made up of the input shaft of the output mechanism, or it can be made up as a separate member from the input shaft and fixed coaxially to the input shaft. In this example, the output member 4 is fixed coaxially to the drive pulley 41, which is the input shaft of the reduction gear 40. A toothed belt 66 is stretched between the drive pulley 41 and a driven pulley (not shown).

[0068] The output member 4 has an output shaft portion 20 in addition to the output-side engaging portion 19.

[0069] The output-side engaging portion 19 and the output shaft portion 20 are directly connected in the axial direction. Specifically, the output-side engaging portion 19 protrudes from one end face 23 on one axial side of the output shaft portion 20 toward one axial direction.

[0070] The output-side engaging portion 19 has a portion that engages with the output-side engaged portion 46 of the engaging element 5, and is an element that receives rotational torque from the engaging element 5 when rotational torque is input to the input member 3 and the engaging element 5 rotates. Also, when rotational torque is input in reverse to the output member 4, it engages with the output-side engaged portion 46 of the engaging element 5 and moves the engaging element 5 in a direction toward the pressed surface 7.

[0071] The output-side engaging portion 19 has a cam function.

[0072] The output-side engaging portion 19 has an output-side engaging surface 21 on its outer circumferential surface that engages with the output-side engaged portion 46 of the engaging element 5.

[0073] The output-side engaging portion 19 is configured to engage (contact) the output-side engaging surface 21, which is provided on its outer circumferential surface, with the output-side engaged portion 46 as the output member 4 or engaging element 5 rotates.

[0074] The output-side engagement surface 21 is located radially inward from the input-side engagement portion 14 and radially outward from the rotational axis O of the output member 4, and is positioned to engage with the output-side engaged portion 46 of the engaging element 5. The distance from the rotational axis O of the output member 4 to the output-side engagement surface 21 is not constant in the circumferential direction.

[0075] The number of output-side engagement surfaces 21 provided by the output-side engagement portion 19 is determined according to the number of engagement elements 5. When the engagement element 5 is composed of multiple engagement elements 5, the output-side engagement portion 19 is also configured to have multiple output-side engagement surfaces 21. In this example, the output-side engagement portion 19 is configured to have two output-side engagement surfaces 21, corresponding to the number of engagement elements 5. That is, the output-side engagement surface 21 is composed of two output-side engagement surfaces 21.

[0076] When the output-side engaging portion 19 is cut by a virtual plane perpendicular to the rotational axis O of the output member 4, the cross-sectional shape of the output-side engaging portion 19 is arbitrary as long as the output-side engaging portion 19 has an output-side engaging surface 21 on its outer circumferential surface. For example, it can be a quadrilateral such as a square, rectangle, parallelogram, or trapezoid, an oval, or a shape similar to these quadrilaterals or ovals.

[0077] The shape of the output-side engaging surface 21 is not limited, as long as it is configured to engage with the output-side engaged portion 46 of the engaging element 5. For example, the output-side engaging surface 21 can be a flat surface parallel to a virtual plane containing the central axis O of the output member 4, or it can be a partially cylindrical convex curved surface, etc. In this example, the output-side engaging surface 21 is a flat surface parallel to a virtual plane containing the central axis O of the output member 4.

[0078] In this example, the output-side engaging portion 19 has a substantially rectangular cross-sectional shape, as shown in Figure 6, when cut by a virtual plane perpendicular to the rotational axis O of the output member 4. More specifically, the outer circumferential surface of the output-side engaging portion 19 is composed of two output-side engaging surfaces 21 arranged parallel to each other, and two convex curved surfaces 22, each partially cylindrical. The two output-side engaging surfaces 21 and the two convex curved surfaces 22 are equally spaced at 180 degrees in the circumferential direction.

[0079] In this example, the output-side engaging portion 19 is symmetrical with respect to a virtual plane that passes through the rotational axis O of the output member 4 and is perpendicular to the two output-side engaging surfaces 21. Furthermore, the output-side engaging portion 19 is symmetrical with respect to a virtual plane that passes through the rotational axis O of the output member 4 and is parallel to the two output-side engaging surfaces 21. That is, the output-side engaging portion 19 has a shape that is twice symmetrical with respect to the central axis O of the output member 4. The output-side engaging portion 19 is located radially inside the two input-side engaging portions 14 and is positioned between the output-side engaged portions 46 of the two engaging elements 5.

[0080] The output shaft portion 20 is an element for connecting the output member 4 and the input portion of the output mechanism so as to be able to transmit rotational torque.

[0081] The output shaft portion 20 has an axial end face 23 on one side, at least a portion of which faces the engaging element 5 in the axial direction.

[0082] The axial end face 23 of the output shaft portion 20 is an element to which the axial end of the output side engaging portion 19 is connected, and is also an element that restricts the axial movement of the engaging element 5.

[0083] The end face 23 on one axial side of the output shaft portion 20 is configured as a flat surface perpendicular to the central axis of the output member 4 in order to restrict the axial movement of the engaging element 5.

[0084] The axial end face 23 of the output shaft portion 20 and the output-side engagement surface 21 are connected via a corner radius portion 25.

[0085] The output shaft portion 20 has a groove portion 26 that extends linearly in a direction perpendicular to a second virtual plane, which is perpendicular to a first virtual plane passing through both ends of the output engagement surface 21 in the circumferential direction and includes the central axis O of the output member 4. This groove portion 26 is located on one axial side of the outer circumferential surface and its phase in the circumferential direction coincides with that of the output engagement surface 21. In this example, since the output engagement surface 21 is made of a flat surface, the second virtual plane corresponds to a virtual plane perpendicular to the output engagement surface 21 and passing through the central axis O of the output member 4.

[0086] The groove 26 is an element for relieving the stress acting on the corner radius 25 that connects the axial end face 23 of the output shaft portion 20 and the output side engagement surface 21.

[0087] With respect to the second virtual plane, the groove shape of the cross-section of the groove 26 is approximately U-shaped or approximately C-shaped. By making the groove shape of the cross-section of the groove 26 approximately U-shaped or approximately C-shaped, it is possible to prevent the presence of any elements within the groove 26 that cause stress concentration.

[0088] The specific configuration of the inner surface 27 of the groove 26, the radial position of the bottom of the groove 26, the axial groove width at the opening 28 of the groove 26, and the axial position of the groove 26 can be arbitrarily set, as long as excessive stress is not concentrated on the inner surface 27 of the groove 26 and the stress acting on the corner radius 25 is relaxed.

[0089] In the reverse input blocking clutch 1, a groove 26 is formed on the outer circumferential surface of the output shaft portion 20, so that the stress acting on the corner R portion 25 is relieved when torque is transmitted by the output member 4. Therefore, the radius of curvature R of the corner R portion 25 25 This can be set to a value that is sufficiently smaller than the radius of curvature of the corner R portion in a conventional reverse input blocking clutch. Specifically, the radius of curvature R of the corner R portion 25 25 This can be set to 0.5 mm or less, preferably 0.3 mm or less.

[0090] That is, the radius of curvature R of corner R section 25 25This can be set to a size approximately the same as the size of the minute gap 69 between the axial end face 23 of the output shaft portion 20 and the axial end face 53 of the engaging element 5.

[0091] The end face 23 on one axial side of the output shaft portion 20 forms a restricting portion 24, at least a part of which faces the engaging element 5 in the axial direction, preventing the engaging element 5 from moving to the other axial side.

[0092] The end face 23 on one axial side of the output shaft portion 20 is not limited in its contour shape, as long as at least a part of it is configured to form a restricting portion 24. For example, it can be configured as a polygon such as a circle or a square.

[0093] In this example, since the output shaft portion 20 has a stepped cylindrical shape, the end face 23 on one axial side of the output shaft portion 20 has a circular contour shape when viewed from the axial direction. Furthermore, since the end on one axial side of the output shaft portion 20 is positioned radially inward of the input-side engaging portion 14 of the input member 3, the end face 23 on one axial side of the output shaft portion 20 has a diameter slightly smaller than the diameter of the inscribed circle of the input-side engaging portion 14.

[0094] In this example, the output-side engaging portion 19 has a substantially rectangular end face shape in which the dimension in the second direction is larger than the dimension in the first direction, and the dimension in the second direction is the same as the diameter of the end face 23 on one axial side of the output shaft portion 20. Therefore, the portion of the end face 23 on one axial side of the output shaft portion 20 that is separated in the first direction from the connection portion with the output-side engaging portion 19 constitutes the restricting portion 24.

[0095] In this example, the restricting portion 24 has a substantially curved shape when viewed from the axial direction. However, the shape of the restricting portion 24 is not limited as long as it can restrict the axial movement of the engaging element 5 and does not hinder the engagement between the input-side engaging portion 14 and the input-side engaged portion 45. From the perspective of effectively preventing the engaging element 5 from moving in the other axial direction, it is preferable that the restricting portion 24 has a shape that allows for a large area to face the engaging element 5.

[0096] The number of restricting portions 24 on the axial end face 23 of the output shaft portion 20 is determined according to the number of engaging elements 5. If the engaging elements 5 are composed of multiple engaging elements 5, the restricting portions 24 are also configured to have multiple restricting portions 24. In this example, the axial end face 23 of the output shaft portion 20 is configured to have two restricting portions 24, corresponding to the number of engaging elements 5. The restricting portions 24 are provided at both ends of the axial end face 23 of the output shaft portion 20 with respect to the first direction. Therefore, the two restricting portions 24 are equally spaced 180 degrees apart in the circumferential direction.

[0097] In this example, a small axial gap 69 is provided between the axial end face 23 of the output shaft portion 20 and the axial end face 53 of the engaging element 5. Specifically, a small axial gap 69 is provided between the restricting portion 24 of the axial end face 23 of the output shaft portion 20 and the axial end face 53 of the engaging element 5. This prevents the restricting portion 24 from becoming a resistance when the engaging element 5 moves radially.

[0098] The size of the aforementioned minute gap is not limited to this, but can be set to, for example, 0.5 mm or less, preferably 0.3 mm or less. In this example, the size of the minute gap is set to 0.2 mm.

[0099] In this example, the radius of curvature of corner R section 25 is R 25 This is set to 0.2 mm, the same size as the aforementioned minute gap.

[0100] With respect to the groove portion 26, the specific configuration of the inner surface 27, the radial position of the bottom of the groove portion 26, the groove width at the opening 28 of the groove portion 26, and the axial position of the groove portion 26, which prevent excessive stress concentration on the inner surface 27 and maximize the stress relaxation effect acting on the corner R portion 25, vary based on factors such as the outer diameter of the output shaft portion 20, the radial distance from the central axis O of the output member 4 to the output side engagement surface 21, and the material of the output member 4, and can be determined by experimentation, simulation, etc.

[0101] The specific configuration of the groove 26 will be explained in more detail below.

[0102] When the groove shape of the cross-section of the groove portion 26 is configured to be approximately U-shaped, the inner surface 27 of the groove portion 26 can be composed of, for example, a first inner surface 29 which is a flat surface facing one side in the axial direction, a second inner surface 30 which is a flat surface facing the other side in the axial direction, and a bottom surface 31 which connects the first inner surface 29 and the second inner surface 30. Compared to the case where the groove shape of the cross-section is approximately C-shaped, such a groove portion 26 does not require an increase in the axial groove width of the groove portion 26 even when the radial distance from the central axis O of the output member 4 to the groove portion 26 is reduced. Therefore, forming the groove portion 26 prevents an excessive decrease in the rigidity and strength of the output member 4.

[0103] When the inner surface 27 of the groove 26 is composed of a first inner surface 29, a second inner surface 30, and a bottom surface 31, the bottom surface 31 can be formed as a partially cylindrical concave surface having a single radius of curvature. Such a groove 26 can be machined by cutting using a common tool such as an end mill, which is advantageous in terms of reducing processing costs.

[0104] Alternatively, if the inner surface 27 of the groove 26 is composed of a first inner surface 29, a second inner surface 30, and a bottom surface 31, the bottom surface 31 may be composed of a first curved surface portion 32 having a concave arc cross-sectional shape connected to the first inner surface 29, a second curved surface portion 33 having a concave arc cross-sectional shape connected to the second inner surface 30, and a bottom flat portion 34 that is substantially parallel to the output-side engagement surface 21 and positioned between the first curved surface portion 32 and the second curved surface portion 33 in the axial direction.

[0105] Alternatively, if the inner surface 27 of the groove 26 is composed of a first inner surface 29, a second inner surface 30, and a bottom surface 31, the bottom surface 31 may be composed of a first curved surface portion 32 having a concave arc-shaped cross-section connected to the first inner surface 29, and a second curved surface portion 33 having a concave arc-shaped cross-section connected to the first curved surface portion 32 and the second inner surface 30, respectively.

[0106] When the bottom surface 31 includes a first curved surface portion 32 and a second curved surface portion 33, the radius of curvature R of the first curved surface portion 32 32 and the radius of curvature R of the second curved surface portion 33 33 can be made different from each other.

[0107] When torque is transmitted by the output member 4, stress concentrates more on the first curved surface portion 32 of the bottom surface 31 that is far from the output-side engagement surface 21 than on the second curved surface portion 33 of the bottom surface 31 that is close to the output-side engagement surface 21. Therefore, when the radius of curvature R of the first curved surface portion 32 32 and the radius of curvature R of the second curved surface portion 33 33 are made different from each other, it is preferable that the radius of curvature R of the first curved surface portion 32 32 is larger than the radius of curvature R of the second curved surface portion 33 33 .

[0108] In the bottom surface 31, the second curved surface portion 33 is less likely to have stress concentration as its radius of curvature R 33 is smaller. Therefore, it is preferable that the radius of curvature R of the second curved surface portion 33 33 is smaller than the radius of curvature R of the first curved surface portion 32 32 . By making the radius of curvature R of the second curved surface portion 33 33 smaller in this way, the stress acting on the corner R portion 25 can be effectively reduced. Also, since it becomes possible to reduce the groove width in the axial direction of the groove portion 26, the axial dimension of the output member 4 can be shortened. The radius of curvature R of the second curved surface portion 33 33 can be set to approximately the same size as the radius of curvature R 25 of the corner R portion 25 that connects the end surface 23 on one axial side of the output shaft portion 20 and the output-side engagement surface 21.

[0109] When the groove shape of the cross section of the groove portion 26 is configured in a substantially C shape, the inner surface 27 of the groove portion 26 can be composed of, for example, only a partial cylindrical concave curved surface having a single radius of curvature.

[0110] In this example, the groove shape of the cross-section of the groove portion 26 is configured to be approximately U-shaped. The inner surface 27 of the groove portion 26 is composed of a first inner surface 29 which is a flat surface facing one side in the axial direction, a second inner surface 30 which is a flat surface facing the other side in the axial direction, and a bottom surface 31 which connects the first inner surface 29 and the second inner surface 30. The bottom surface 31 is composed of a concave curved surface in the shape of a partial cylindrical surface having a single radius of curvature. Furthermore, the first inner surface 29 and the second inner surface 30 are arranged approximately parallel to the end surface 23 on one side in the axial direction of the output shaft portion 20.

[0111] In this example, which includes such a groove 26, even if the radial distance from the central axis O of the output member 4 to the groove 26 is reduced compared to the case where the groove shape in cross-section is approximately C-shaped, it is not necessary to increase the axial groove width of the groove 26. Therefore, forming the groove 26 prevents the rigidity and strength of the output member 4 from being reduced more than necessary. In addition, since the groove 26 can be machined by cutting using a general tool such as an end mill, it is advantageous in terms of reducing processing costs.

[0112] The radial distance D from the central axis O of the output member 4 to the groove 26. 26 This corresponds to the radial position of the bottom of the groove 26. Such a radial distance D 26 For example, the radial distance D from the central axis O of the output member 4 to the output-side engagement surface 21. 21 It can be determined based on this. Figure 9 shows the radial distance D, determined by simulation. 26 and radial distance D 21 The ratio (D 26 / D 21 This graph shows the relationship between the radial distance D and the maximum torque required to avoid plastic deformation in the corner radius 25. As can be seen from Figure 9, 26 This is the radial distance D 21 It is preferable to set it to a size of approximately the same magnitude as the radial distance D. Specifically, the radial distance D 26 This is the radial distance D 21 0.7 times or more and 1.4 times or less, preferably the radial distance D 21 It can be set to a size between 0.85 and 1.25 times the original size.

[0113] In this example, the radial distance D from the central axis O of the output member 4 to the groove 26 is... 26 This is the radial distance D from the central axis O of the output member 4 to the output side engagement surface 21. 21 It is set to be approximately the same size as the radial distance D. 26 This value is set to the optimal value determined by the simulation shown in Figure 9.

[0114] The axial groove width W at the opening 28 of the groove 26 26 This value changes according to the magnitude of the radius of curvature of the curved surface that constitutes the bottom surface 31 of the groove 26. The smaller the value, the greater the stress acting on the inner surface 27 of the groove 26, and conversely, the larger the value, the smaller the stress acting on the inner surface 27 of the groove 26.

[0115] In this example, the bottom surface 31 is composed of a partially cylindrical concave surface having a single radius of curvature, so the axial groove width W at the opening 28 of the groove 26 26 The size is set to twice the radius of curvature of the base 31.

[0116] The axial position of the groove 26 is determined by the axial dimension L from the end face 23 on one axial side of the output shaft portion 20 to the opening 28 of the groove 26. 26 It can be expressed as follows: The axial dimension L 26 The smaller this value, the greater the stress relief effect on the corner radius 25. Conversely, the axial dimension L 26 The larger the value of , the smaller the stress relaxation effect acting on the corner radius 25.

[0117] In this example, the axial dimension L is the distance from the end face 23 on one axial side of the output shaft portion 20 to the opening 28 of the groove portion 26. 26 The size is the axial groove width W at the opening 28 of the groove 26. 26 It is set to a value smaller than . Axial dimension L 26 The groove width W 26 It can be set to 1 / 2 or less, preferably 1 / 3 or less. In this example, the axial dimension L 26 The groove width W26 It is set to be approximately 1 / 3 the size of the original.

[0118] The number of grooves 26 on the output shaft portion 20 is determined according to the number of output-side engagement surfaces 21 on the output-side engagement portion 19. If the output-side engagement surfaces 21 are composed of multiple output-side engagement surfaces 21, the grooves 26 are also configured to have multiple grooves 26. In this example, the output shaft portion 20 is configured to have two grooves 26, corresponding to the number of output-side engagement surfaces 21. The grooves 26 are provided at two locations on opposite sides of the outer circumferential surface of the output shaft portion 20. The two grooves 26 are equally spaced 180 degrees apart in the circumferential direction.

[0119] Since the output shaft portion 20 has a groove portion 26 formed on one axial side of its outer circumferential surface, at the axial end of the output shaft portion 20, and in the portion adjacent to the axial side of the groove portion 26, the width at the radially outer end is the axial dimension L. 26 It has a flange portion 35 which is the same as the other. The end face on one axial side of the flange portion 35 is formed by a restricting portion 24, and the side surface on the other axial side of the flange portion 35 is formed by the inner surface 27 of the groove portion 26, specifically the axial side portion of the bottom surface 31 and the second inner surface 30.

[0120] In the reverse input blocking clutch 1 of this disclosure, the output shaft portion 20 has a groove portion 26 that extends linearly in a direction perpendicular to a second virtual plane that includes the central axis O of the output member 4, and perpendicular to a first virtual plane passing through both ends of the output side engagement surface 21 in the circumferential direction, in a portion of the axial side of the outer circumferential surface where the phase in the circumferential direction coincides with that of the output side engagement surface 21. Therefore, the stress acting on the corner R portion 25 can be relieved when torque is transmitted by the output member 4. As a result, the radius of curvature R of the corner R portion 25 25 Because the radius can be reduced, interference between the corner radius 25 and the engaging element 5 can be prevented. Therefore, without using a spacer, the end face 23 on one axial side of the output shaft portion 20 can directly restrict the engaging element 5 from moving to the other axial side.

[0121] Furthermore, since the groove shape of the cross-section of the groove portion 26 is configured to be approximately U-shaped or approximately C-shaped, it is possible to prevent excessive stress from concentrating on the inner surface 27 of the groove portion 26 when torque is transmitted by the output member 4.

[0122] Therefore, the reverse input blocking clutch 1 of this disclosure can reduce the number of parts and prevent stress concentration in the output member 4.

[0123] In this example, the output shaft portion 20 has a large diameter portion 36, a medium diameter portion 37, and a small diameter portion 38, in that order from one side in the axial direction. The large diameter portion 36 has an outward-facing flange portion 39 that protrudes radially outward along its entire circumference in the axial middle portion of its outer circumferential surface. In this example, the drive pulley 41 of the reduction gear 40 is externally fitted and fixed to the medium diameter portion 37.

[0124] In this example, the large-diameter portion 36 of the output shaft 20 is rotatably supported relative to the pressed member 2. Specifically, the large-diameter portion 36 of the output shaft 20 is rotatably supported relative to the pressed member 2 by a radial rolling bearing 42a. The radial rolling bearing 42a is axially sandwiched between an outward-facing flange portion 39 provided on the outer circumferential surface of the large-diameter portion 36 and an inward-facing flange portion 12 provided on the inner circumferential surface of the pressed member 2.

[0125] In this example, the output shaft portion 20 has a mounting shaft portion 43 adjacent to one side of the output-side engaging portion 19 in the axial direction.

[0126] The mounting shaft portion 43 is an element for attaching a stopper member 54 to prevent the engaging element 5 from moving in one axial direction.

[0127] The mounting shaft portion 43 protrudes in one axial direction from the axial end face 67 of the output side engaging portion 19.

[0128] The mounting shaft portion 43 is not limited in shape as long as it is configured to accommodate the stopper member 54. The shape of the mounting shaft portion 43 can be appropriately changed depending on the type of stopper member 54 used. Specifically, the mounting shaft portion 43 can be any shape, such as a cylindrical shape, a truncated cone shape, an oval prism shape, an elliptical prism shape, a rectangular prism shape, or other prism shapes.

[0129] In this example, the stopper member 54 is composed of a segmented annular retaining ring. Therefore, the mounting shaft portion 43 has a cylindrical shape suitable for locking the retaining ring, which is the stopper member 54. The mounting shaft portion 43 has an outer diameter that is the same as the dimension in the first direction of the end face 67 on one axial side of the output side engaging portion 19. In addition, the mounting shaft portion 43 has a locking groove 68 in the axial middle portion of its outer circumferential surface for locking the retaining ring, which is the stopper member 54.

[0130] In this example, the mounting shaft portion 43 is provided at one end of the output member 4 on the axial side. However, the output member 4 may also have a shaft portion on one axial side of the mounting shaft portion 43, for example, inserted inside the input shaft portion 15, to increase the coaxiality between the output member 4 and the input member 3.

[0131] [Engagement element] The engaging element 5 has a pressing surface 44 facing the pressed surface 7, an input-side engaged portion 45 that can engage with the input-side engaging portion 14, and an output-side engaged portion 46 that can engage with the output-side engaging portion 19, and is arranged to allow movement in a first direction which is the near-far direction relative to the pressed surface 7.

[0132] When rotational torque is input to the input member 3, the engaging element 5 moves away from the pressed surface 7 in the first direction, based on the input-side engaging portion 14 engaging with the input-side engaged portion 45, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output-side engaged portion 46 with the output-side engaging portion 19. Conversely, when rotational torque is input in reverse to the output member 4, the engaging element 5 presses the pressing surface 44 against the pressed surface 7, based on the output-side engaging portion 19 engaging with the output-side engaged portion 46, thereby frictionally engaging the pressing surface 44 with the pressed surface 7.

[0133] The engaging element 5 can be composed of two engaging elements 5, or of three or more engaging elements 5, as long as it has the above configuration.

[0134] The engaging element 5 can be manufactured by any method. For example, the engaging element 5 can be manufactured by pressing, sintering, forging, casting, and / or machining. In this example, the engaging element 5 is a press-formed metal sheet manufactured by pressing.

[0135] The shape of the engaging element 5 is arbitrary as long as it comprises a pressing surface 44, an input-side engaged portion 45, and an output-side engaged portion 46, and can achieve the above-mentioned functions, and a wide range of conventional engaging element shapes can be adopted.

[0136] In this example, the engaging element 5 is composed of two engaging elements 5. Each engaging element 5 has the function of an engaging element 5. Each engaging element 5 has a substantially semicircular end face shape when viewed from the axial direction and has a symmetrical shape with respect to the width direction. The configuration of each engaging element 5 will be described below.

[0137] The pressing surface 44 is provided on the radially outer surface of the engaging element 5 facing the pressed surface 7. The shape and size of the pressing surface 44 are arbitrary as long as they can frictionally engage with the pressed surface 7. The pressing surface 44 can be made up of the entire radially outer surface of the engaging element 5, or it can be made up of a part of it. One pressing surface 44 can be provided for one engaging element 5, or multiple pressing surfaces 44 can be provided. The radius of curvature of the pressing surface 44 can be the same as the radius of curvature of the pressed surface 7, or it can be smaller than the radius of curvature of the pressed surface 7.

[0138] In this example, the pressing surface 44 is composed of two pressing surfaces 44 located at two positions on the radially outer surface of the engaging element 5 that are spaced apart from each other in the circumferential direction. Each pressing surface 44 is composed of a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the surface to be pressed 7.

[0139] The portion of the radially outer surface of the engaging element 5 that is circumferentially away from the two pressing surfaces 44 is located radially inward from the circumscribed circle that is centered on the rotation center O of the input member 3 and tangent to the two pressing surfaces 44, when viewed from the axial direction. In other words, when the two pressing surfaces 44 are in contact with the surface to be pressed 7, the portion that is circumferentially away from the two pressing surfaces 44 does not come into contact with the surface to be pressed 7.

[0140] The pressing surface 44 preferably has a surface property that results in a higher coefficient of friction with respect to the pressed surface 7 than the other parts of the engaging element 5. Furthermore, the pressing surface 44 can be integrally formed with the other parts of the engaging element 5, or it can be formed from the surface of a friction material fixed to the other parts of the engaging element 5 by adhesive or other means.

[0141] The input-side engaged portion 45 engages with the input-side engaged portion 14 as the input member 3 rotates, and is an element that receives the rotational torque input from the input member 3. The shape of the input-side engaged portion 45 is not limited as long as it is configured to be able to engage with the input-side engaged portion 14.

[0142] In this example, the input-side engaged portion 45 is provided in the radially intermediate portion of the widthwise center of the engaging element 5. More specifically, the input-side engaged portion 45 is composed of a through hole that penetrates the radially intermediate portion of the widthwise center of the engaging element 5 in the axial direction.

[0143] The input-side engaged portion 45 is sized to allow the input-side engaged portion 14 to be loosely inserted. Therefore, when the input-side engaged portion 14 is inserted inside the input-side engaged portion 45, there are gaps between the input-side engaged portion 14 and the inner surface of the input-side engaged portion 45 in the width direction and the radial direction of the engaging element 5. As a result, the input-side engaged portion 14 can be displaced relative to the input-side engaged portion 45 in the rotational direction of the input member 3, and the input-side engaged portion 45 can be displaced relative to the input-side engaged portion 14 in the radial direction of the engaging element 5.

[0144] In this example, the radially inner surface 47 of the inner surface of the input-side engaged portion 45, which faces radially outward, is composed of a flat surface perpendicular to the first direction, and the radially outer surface 48 of the inner surface of the input-side engaged portion 45, which faces radially inward, is composed of a curved surface having a substantially arc-shaped contour or a composite surface having a substantially V-shaped contour when viewed from the axial direction. The circumferential surface 49 connecting the ends on both sides of the radially inner surface 47 in the second direction and the ends on both sides of the radially outer surface 48 in the second direction is composed of a partially cylindrical concave curved surface.

[0145] The output-side engaged portion 46 engages with the output-side engaged portion 19 as the engaging element 5 rotates, and is an element for outputting the rotational torque input from the input member 3 to the engaging element 5 to the output member 4. The shape of the output-side engaged portion 46 is not limited as long as it is configured to engage with the output-side engaged portion 19. In this example, the output-side engaged portion 46 is provided at the center in the width direction of the radially inner surface of the engaging element 5.

[0146] In this example, the engaging element 5 has a flat surface portion 50 on its radially inner surface that is perpendicular to the radial direction of the engaging element 5, and has two protrusions 51 projecting radially inward at two positions on the flat surface portion 50 in the width direction of the engaging element 5. The output-side engaged portion 46 is composed of the portion of the flat surface portion 50 that is located between the two protrusions 51 in the width direction. In this example, the width dimension of the output-side engaged portion 46, i.e., the distance between the two protrusions 51, is larger than the width dimension of the output-side engaging surface 21 of the output-side engaging portion 19.

[0147] In the reverse input blocking clutch 1 of this example, the pressing surfaces 44 of the two engaging elements 5 are oriented radially toward opposite sides of each other, and the flat surfaces 50 are facing each other, with each engaging element 5 positioned radially inward of the housing element 8, allowing movement in the first direction. Furthermore, the two input-side engaging portions 14 of the input member 3, positioned on one axial side, are inserted axially into the respective input-side engaged portions 45 of the two engaging elements 5, and the output-side engaging portion 19 of the output member 4, positioned on the other axial side, is inserted axially between the output-side engaged portions 46 of the two engaging elements 5. In other words, the two engaging elements 5 are positioned so that their respective output-side engaged portions 46 sandwich the output-side engaging portion 19 from the radial outside.

[0148] With the two engaging elements 5 positioned radially inward of the pressed member 2, the inner diameter of the pressed surface 7 and the radial dimensions of the engaging elements 5 are regulated such that a gap exists in at least one of the following areas: the space between the pressed surface 7 and the two pressing surfaces 44, and the space between the tip faces of the two combinations of protrusions 51 formed by the two protrusions 51 of the two engaging elements facing each other.

[0149] In this example, the engaging element 5 has a constant axial dimension along its radial direction. The end face 52 on one axial side and the end face 53 on the other axial side of the engaging element 5 are arranged parallel to each other and are each configured as flat surfaces. Furthermore, the flat surface portion 50 that constitutes the radial inner surface of the engaging element 5 is connected at right angles to the end face 52 on one axial side and the end face 53 on the other axial side.

[0150] [Stopper component] The reverse input blocking clutch 1 in this example has a stopper member 54 as an optional component.

[0151] The stopper member 54 is an element that restricts the axial movement of the engaging element 5 relative to the output member 4 to one side.

[0152] The stopper member 54 is attached to the mounting shaft portion 43 of the output member 4. The stopper member 54 can be positioned to directly face the engaging element 5 in the axial direction, thereby directly restricting the movement of the engaging element 5 in one axial direction, or it can be positioned with a spacer 55 in between, thereby restricting the movement of the engaging element 5 in one axial direction via the spacer 55.

[0153] In this example, the stopper member 54 is positioned with a spacer 55 in between it and the engaging element 5, and the movement of the engaging element 5 in one axial direction is restricted via the spacer 55.

[0154] In this example, the stopper member 54 is composed of a segmented annular retaining ring and is locked into a locking groove 68 formed on the outer surface of the mounting shaft portion 43.

[0155] [Spacer] The reverse input blocking clutch 1 in this example has, as an optional component, a spacer 55 positioned between the axial end face 52 of the engaging element 5 and the stopper member 54.

[0156] The spacer 55 is positioned between the axial end face 52 of the engaging element 5 and the stopper member 54, and is an element that aligns the axial position of the pressing surface 44 of the engaging element 5 with the axial position of the pressed surface 7 of the pressed member 2.

[0157] The shape, size, and material of the spacer 55 are not limited, as long as it is positioned between the axial end face 52 of the engaging element 5 and the stopper member 54, and is configured to align the axial position of the pressing surface 44 of the engaging element 5 with the axial position of the pressed surface 7 of the pressed member 2.

[0158] In this example, the spacer 55 is positioned around the output-side engaging portion 19 and between the axial end face 52 of each of the two engaging elements 5 and the stopper member 54.

[0159] The spacer 55 can be made of synthetic resin, rubber, metal material, or the like.

[0160] In this example, the spacer 55 is constructed in a flat plate shape and has an end face shape that is approximately rectangular or approximately oval when viewed from the axial direction. In this example, the end face 56 on one axial side and the end face 57 on the other axial side of the spacer 55 are arranged parallel to each other and are each constructed as a flat surface.

[0161] In this example, the spacer 55 has a through hole 58 through which the output-side engaging portion 19 is inserted. The through hole 58 penetrates the central part of the spacer 55 in the axial direction, has a roughly rectangular or oval opening shape when viewed from the axial direction, and is sized to allow the output-side engaging portion 19 to be inserted without rattling.

[0162] [Biasing member] The reverse input blocking clutch 1 in this example further comprises a biasing member 59 as an optional component.

[0163] The biasing member 59 elastically biases the engaging element 5 toward the pressed surface 7. The biasing member 59 can be made of a spring such as a leaf spring, coil spring, or disc spring, or an elastic material such as rubber, elastomer, or synthetic resin. The number of biasing members 59 is not particularly limited and is determined appropriately according to the number of engaging elements 5.

[0164] In this example, the biasing member 59 is composed of two biasing members 59 positioned at two locations in the width direction between the radially inner surfaces of the two engaging elements 5, and each biasing member 59 is composed of a compression coil spring. A protrusion 51 is inserted into the inside of both ends in the extension direction of each biasing member 59. This prevents each biasing member 59 from falling out of the space between the two engaging elements 5.

[0165] The two biasing members 59 elastically bias the two engaging elements 5 toward the pressed surface 7 by the force that attempts to restore their elasticity. As a result, in the neutral state where no torque is applied to either the input member 3 or the output member 4, the pressing surfaces 44 of the two engaging elements 5 come into contact with the pressed surface 7.

[0166] [Support members] The reverse input blocking clutch 1 in this example further comprises a support member 60 as an optional component.

[0167] The support member 60 is an element for rotatably supporting the other axial end (small diameter portion 38) of the output shaft portion 20.

[0168] The support member 60 comprises a cylindrical bearing holder 61, a partial cylindrical portion 62 extending axially from a single circumferential position at one end of the bearing holder 61 on one axial side, and an outward flange portion 63 extending radially outward from one end of the partial cylindrical portion 62 on one axial side.

[0169] The support member 60 is supported and fixed to the housing element 8 by screwing a bolt 65, which is inserted through a through hole 64 provided in the outward flange portion 63, into a threaded hole 13 provided in the housing element 8.

[0170] The other axial end (small diameter portion 38) of the output shaft portion 20 is rotatably supported by the support member 60 via a radial rolling bearing 42b held by the bearing holding portion 61.

[0171] In the illustrated example, the radial rolling bearings 42a and 42b that rotatably support the output shaft 20 are each ball bearings using balls as rolling elements. However, the radial rolling bearings supporting the output shaft 20 can also be constructed using tapered roller bearings or cylindrical roller bearings using tapered rollers as rolling elements. Furthermore, different types of bearings can be used for the radial rolling bearings 42a and 42b.

[0172] <Explanation of the operation of the reverse input blocking clutch> The operation of the reverse input blocking clutch 1 in this example will be explained using Figures 7 and 8. Note that Figures 7 and 8 omit the biasing member 59 and exaggerate the radial gap between the input member 3 and the output member 4 and the two engaging elements 5.

[0173] When rotational torque is applied to the input member 3, the two engaging elements 5 move away from the pressed surface 7, regardless of the rotation direction of the input member 3. More specifically, as shown in Figure 7, the input-side engaging portion 14 rotates inside the input-side engaged portion 45 in the direction of rotation of the input member 3 (counterclockwise in the example of Figure 7).

[0174] This reduces the gap between the radially inner surface 16 of the input-side engaging portion 14 and the radially inner surface 47 of the input-side engaged portion 45, causing the radially inner surface 16 of the input-side engaging portion 14 to come into contact with the radially inner surface 47 of the input-side engaged portion 45.

[0175] From this state, as the input member 3 rotates further, the radially inner surface 16 of the input-side engaging portion 14 presses the radially inner surface 47 of the input-side engaged portion 45 radially inward, causing the engaging element 5 to move away from the pressed surface 7. That is, the two engaging elements 5 move radially inward, moving closer to each other based on their engagement with the input member 3, causing the radially inner surfaces of the two engaging elements 5 to approach each other, and the output-side engaged portion 19 of the output member 4 to be clamped from both radial sides by the output-side engaged portions 46 of the two engaging elements 5.

[0176] In this way, the output member 4 is rotated so that the output-side engaging surface 21 of the output-side engaging portion 19 is parallel to the output-side engaged portion 46, while the output-side engaging portion 19 and the output-side engaged portion 46 of the engaging element 5 are engaged without any rattle. As a result, the rotational torque input to the input member 3 is transmitted to the output member 4 via the two engaging elements 5 and output from the output member 4.

[0177] When rotational torque is applied in reverse to the output member 4, the two engaging elements 5 move toward the pressed surface 7, regardless of the rotation direction of the output member 4. Specifically, as shown in Figure 8, the output-side engaging portion 19 rotates in the direction of rotation of the output member 4 (clockwise in the example of Figure 8) inside the output-side engaged portions 46 of the two engaging elements 5. The output-side engaging surface 21 of the outer circumferential surface of the output-side engaging portion 19 presses the output-side engaged portions 46 radially outward, causing the two engaging elements 5 to move toward the pressed surface 7.

[0178] In other words, the two engaging elements 5 move radially outward, away from each other, based on their engagement with the output member 4, so that the pressing surfaces 44 of the two engaging elements 5 come into contact with the pressed surface 7 and frictionally engage with the pressed surface 7.

[0179] As a result, the rotational torque reversed into the output member 4 is either completely blocked and not transmitted to the input member 3, or only a portion of the rotational torque reversed into the output member 4 is transmitted to the input member 3 and the rest is blocked.

[0180] In order to completely block the rotational torque that is reverse-input to the output member 4 and prevent it from being transmitted to the input member 3, the engaging element 5 is braced (clamped) between the output-side engaging part 19 and the pressed member 2 so that the pressing surface 44 of the engaging element 5 does not slide (rotate relative to) the pressed surface 7, thereby locking the output member 4.

[0181] To ensure that only a portion of the rotational torque inverted to the output member 4 is transmitted to the input member 3 and the remainder is blocked, the engaging element 5 is braced (clamped) between the output-side engaging portion 19 and the pressed member 2 so that the pressing surface 44 of the engaging element 5 slides against the pressed surface 7, thereby semi-locking the output member 4.

[0182] In the reverse input blocking clutch 1 of this example, the size of the gaps between each component is adjusted so that the above operation is possible. In particular, when the pressing surfaces 44 of the two engaging elements 5 are in contact with the pressed surface 7, a gap exists between the radially inner surface 16 of the input-side engaging portion 14 and the radially inner surface 47 of the input-side engaged portion 45.

[0183] This prevents the radial outward movement of the engaging element 5 from being blocked by the input-side engaging part 14 when rotational torque is input in reverse to the output member 4, and also ensures that even after the pressing surface 44 contacts the pressed surface 7, the surface pressure acting on the contact area between the pressing surface 44 and the pressed surface 7 changes according to the magnitude of the rotational torque input in reverse to the output member 4, thereby ensuring that the output member 4 is properly locked or partially locked.

[0184] In the reverse input blocking clutch 1 of this disclosure, a groove 26 is formed on the outer circumferential surface of the output shaft portion 20, thereby easing the stress acting on the corner R portion 25, and thereby reducing the radius of curvature R of the corner R portion 25. 25 Because the radius can be reduced, interference between the corner radius 25 and the engaging element 5 can be prevented. Therefore, without using a spacer, the engaging element 5 can be directly restricted from moving to the other axial side by the end face 23 on one axial side of the output shaft portion 20. Specifically, the engaging element 5 can be directly restricted from moving to the other axial side by the restricting portion 24 of the end face 23 on one axial side of the output shaft portion 20.

[0185] Furthermore, in the reverse input blocking clutch 1 of this disclosure, the groove shape of the cross-section of the groove portion 26 is configured to be approximately U-shaped or approximately C-shaped, which prevents excessive stress from concentrating on the inner surface 27 of the groove portion 26 when torque is transmitted by the output member 4.

[0186] [Example 2] A second example of the embodiments of this disclosure will be described with reference to Figures 10 and 11.

[0187] In this example, only the configuration of the inner surface 27 of the groove 26 differs from the structure of the first example. The structure of the other parts is the same as the structure of the reverse input blocking clutch 1 of the first example.

[0188] The inner surface 27 of the groove 26 in this example is composed of a first inner surface 29, a second inner surface 30, and a bottom surface 31. The bottom surface 31 is composed of a first curved surface portion 32 having a concave arc cross-sectional shape connected to the first inner surface 29, a second curved surface portion 33 having a concave arc cross-sectional shape connected to the second inner surface 30, and a bottom flat portion 34 which is substantially parallel to the output-side engagement surface 21 and is positioned between the first curved surface portion 32 and the second curved surface portion 33 in the axial direction.

[0189] In this example, the radius of curvature R of the first curved surface portion 32 is also shown. 32 and the radius of curvature R of the second curved surface portion 33 33 (R 32 ≠R 33 Specifically, the radius of curvature R of the second curved surface portion 33. 33 The radius of curvature R of the first curved surface portion 32 32 Smaller than (R 32 >R 33 In particular, in this example, the radius of curvature R of the second curved surface 33 33 The radius of curvature of corner R section 25 is R 25 (R 32 >R 33 ≒R 25 ).

[0190] In this example, the radius of curvature R of the first curved surface portion 32 that constitutes the bottom surface 31 of the inner surface 27 of the groove portion 26. 32 and the radius of curvature R of the second curved surface portion 33 33 The radius of curvature R of the first curved surface 32 is made different from that of the first curved surface 32 where stress is likely to concentrate. 32 The radius of curvature R of the second curved surface 33, which is less prone to stress concentration. 33This is made larger than the first curved surface 32. In particular, in this example, the radius of curvature R of the second curved surface 33 33 The radius of curvature of corner R section 25 R 25 Because it has been reduced to a size that is almost the same as the original, the stress acting on the corner R portion 25 can be sufficiently reduced. Figure 11 shows the radius of curvature R of the second curved surface portion 33 as determined by simulation. 33 and the radius of curvature R of corner R section 25 25 Ratio (R 33 / R 25 This graph shows the relationship between the radius of curvature R of the second curved surface 33 and the magnitude of the maximum shear stress acting on the corner R portion 25. As can be seen from Figure 11, the radius of curvature R of the second curved surface 33 33 By reducing the radius of curvature R of the second curved surface 33, the maximum shear stress acting on the corner R portion 25 can be reduced. 33 The radius of curvature of corner R section 25 R 25 By reducing its size to almost the same size as the original, the stress acting on the corner radius 25 can be sufficiently reduced.

[0191] The composition and effects of the other parts of the second example are the same as those of the first example.

[0192] [Example 3] A third example of the embodiments of this disclosure will be described with reference to Figure 12.

[0193] In this example, only the groove shape of the cross-section of the groove portion 26 differs from the structure of the first example. The structure of the other parts is the same as that of the reverse input blocking clutch 1 in the first example.

[0194] In this example, the groove shape of the cross-section of the groove 26 is configured to be roughly C-shaped.

[0195] Therefore, the inner surface 27 of the groove 26 is composed solely of a partially cylindrical concave surface having a single radius of curvature.

[0196] The magnitude of the central angle θ of the groove shape in the cross-section of the groove portion 26 is not limited, as long as it can relieve the stress acting on the corner radius portion 25 and prevent excessive stress concentration on the inner surface 27 of the groove portion 26. In this example, the central angle θ of the groove shape in the cross-section of the groove portion 26 is set to a value greater than 180 degrees. However, the central angle θ of the groove shape in the cross-section of the groove portion 26 can be less than 180 degrees or 180 degrees.

[0197] In this example, the groove shape of the cross-section of the groove portion 26 is approximately C-shaped, and the inner surface 27 of the groove portion 26 is composed only of a partially cylindrical concave surface with a single radius of curvature. Therefore, the groove portion 26 can be machined by cutting using a drilling tool, for example. This is advantageous in terms of reducing processing costs.

[0198] The composition and effects of the other parts of the third example are the same as those of the first example. [Examples]

[0199] This section describes a simulation conducted to verify the effectiveness of the reverse input blocking clutch described herein.

[0200] In this simulation, five output members 4 (Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2) having the cross-sectional shapes shown in Figures 13(A) to 13(E) were prepared. Each of the five output members 4 has an output-side engagement portion 19 on one axial side having two output-side engagement surfaces 21 arranged parallel to each other, and an output shaft portion 20 on the other axial side.

[0201] Then, for each of these output members 4, with the other axial end of the output shaft portion 20 fixed, a moment of 7 Nm was applied to one axial end of the output side engaging portion 19 around the central axis O of the output member 4, and the magnitude of the maximum shear stress acting on the corner R portion 25 connecting the output side engaging surface 21 and the axial end surface 23 of the output shaft portion 20 was determined.

[0202] The specifications for each output member 4 (Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2) are as follows.

[0203] (Example 1) The cross-sectional shape of the output member 4 of Example 1 is shown in Figure 13(A). Outer diameter d of output shaft portion 20 20 :17mm The radial distance D from the central axis O of the output member 4 to the output-side engagement surface 21. 21 :2.5mm Radius of curvature R of corner R section 25 25 : 0.2mm Groove shape of the cross-section of groove 26: roughly U-shaped Shape of the bottom surface 31 of the groove 26: A concave surface in the shape of a partial cylindrical surface having a single radius of curvature. Radius of curvature of base 31: 2.5 mm Groove width W at the opening 28 of groove 26 26 :5mm The radial distance D from the central axis O of the output member 4 to the groove 26. 26 :2.5mm The axial dimension L is from the end face 23 on one axial side of the output shaft portion 20 to the opening 28 of the groove portion 26. 26 : 1.5mm Axial dimension from the other axial end (fixed portion) of the output shaft 20 to the end face 23 on the one axial side: 39.54 mm Axial dimension from one axial end (moment-loaded portion) of the output engagement portion 19 to one axial end face 23 of the output shaft portion 20: 25.5 mm

[0204] (Example 2) Figure 13(B) shows the cross-sectional shape of the output member 4 of Example 2. The radial distance D from the central axis O of the output member 4 to the groove 26 is... 26 Except for the fact that the length is 2.775 mm, it is the same as in Example 1.

[0205] (Example 3) Figure 13(C) shows the cross-sectional shape of the output member 4 of Example 3. The bottom surface 31 of the groove 26 is composed of a first curved surface 32, a second curved surface 33, and a bottom flat surface 34, of which the radius of curvature R of the first curved surface 32 is 32 The diameter is 2.5 mm, and the radius of curvature R of the second curved surface portion 33 is 33 Except for the fact that the diameter is 0.2 mm, it is the same as in Example 2.

[0206] (Comparative Example 1) Figure 13(D) shows the cross-sectional shape of the output member 4 of Comparative Example 1. It is the same as in Example 1, except that the outer circumferential surface of the output shaft portion 20 does not have a groove portion 26.

[0207] (Comparative Example 2) Figure 13(E) shows the cross-sectional shape of the output member 4 of Comparative Example 2. The outer circumferential surface of the output shaft portion 20 does not have a groove portion 26, and the radius of curvature of the corner R portion 25 is R 25 Except for the fact that the diameter is 1.8 mm, it is the same as in Example 1.

[0208] Table 1 shows the magnitude (MPa) of the maximum shear stress acting on the corner radius 25 for each output member 4 (Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2), and the percentage reduction in the maximum shear stress compared to Comparative Example 1.

[0209] [Table 1]

[0210] [Consideration] We will discuss the simulation results while referring to Table 1.

[0211] Comparing Comparative Example 1, which does not have a groove 26 on the outer circumferential surface of the output shaft portion 20, with Comparative Example 2, the radius of curvature R of the corner R portion 25 25 It can be observed that reducing the value increases the maximum shear stress acting on the corner radius 25.

[0212] Comparing Comparative Example 1 with Example 1, it can be seen that by forming a groove 26 in the axial portion of the outer circumferential surface of the output shaft portion 20 in a part where the phase in the circumferential direction coincides with that of the output side engagement surface 21, and by making the groove shape of the cross-section of the groove 26 substantially U-shaped, the maximum shear stress acting on the corner radius portion 25 is reduced.

[0213] Comparing Example 1 and Example 2, the radial distance D from the central axis O of the output member 4 to the groove 26 is... 26 The radial distance D from the central axis O of the output member 4 to the output side engagement surface 21. 21 The radial distance D from the central axis O of the output member 4 to the output side engagement surface 21 is greater than when it is the same. 21 It was observed that the maximum shear stress acting on the corner radius 25 decreased when the value was increased to 1.1 times the original value.

[0214] Comparing Example 2 and Example 3, the bottom surface 31 of the groove 26 is composed of a first curved surface 32, a second curved surface 33, and a bottom flat surface 34, and the radius of curvature R of the second curved surface 33. 33 The radius of curvature R of the first curved surface portion 32 32 By making it smaller, it is observed that the maximum shear stress acting on the corner radius 25 is reduced compared to when the bottom surface 31 is made of a concave curved surface with a single radius of curvature.

[0215] In each embodiment, a structure was described in which the movement of the engaging element 5 to one axial side is prevented using a stopper member 54 and a spacer 55, which are composed of retaining rings. However, the reverse input blocking clutch of this disclosure can be implemented in combination with a structure in which the movement of the engaging element to one axial side is directly restricted by the stopper member, or by other members. [Explanation of Symbols]

[0216] 1. Reverse input blocking clutch 2 Pressed member 3 Input Members 4 Output component 5 Engagement element 7 Pressed surface 8 Housing elements 9. Large diameter cylindrical surface 10 Small diameter cylindrical surface part 11 Connection surface 12 Inward flange section 13 screw holes 14 Input side engagement part 15 Input shaft section 16 Radial inner surface 17 Input flange section 18 Radial outer surface 19 Output side engagement part 20 Output shaft section 21 Output side engagement surface 22 Convex curved surface 23 End face 24 Regulatory Department 25 Corner R section 26 Groove 27 Inner self 28 Opening 29 1st inner surface 30 Second inner surface 31 Bottom 32 1st curved surface part 33 Second curved surface part 34 Bottom plane part 35 Guard section 36 Large diameter section 37 Medium diameter part 38 Small diameter section 39 Outward flange section 40 Reducer 41 Drive pulley 42a, 42b Radial rolling bearings 43 Mounting shaft 44 Pressing surface 45 Input side engaged portion 46 Output side engaged part 47 Radial inner surface 48 Radial outer surface 49 Circumferential side view 50 Flat surface section 51 Convex part 52 End face 53 End face 54 Stopper member 55 Spacers 56 End face 57 End face 58 Through hole 59. Biasing member 60 Support member 61 Bearing retaining part 62 Partial cylindrical section 63 Outward flange section 64 Through hole 65 volts 66 Toothed belt 67 End face 68 Locking groove 69 Tiny gaps

Claims

1. A member to be pressed having a surface to be pressed on its inner circumferential surface, An input member having an input-side engaging portion located radially inward of the pressed surface, connected to an input-side mechanism on one axial side, and arranged coaxially with the pressed surface, An output member having an output-side engaging portion located radially inward from the input-side engaging portion, connected to the output-side mechanism on the other axial side, and arranged coaxially with the pressed surface, An engaging element having a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and arranged to be movable in the radial direction, Equipped with, When rotational torque is input to the input member, the engaging element moves radially away from the pressed surface based on the input-side engaging portion engaging 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. Conversely, when rotational torque is input in reverse to the output member, the engaging element presses the pressing surface against the pressed surface based on the output-side engaging portion engaging with the output-side engaged portion, thereby frictionally engaging the pressing surface with the pressed surface. The output-side engaging portion has an output-side engaging surface on its outer circumferential surface that engages with the output-side engaged portion. The output member has an output shaft portion, the output shaft portion having at least a part of which has an axial end face on one side that faces the engaging element in the axial direction, The end face on one axial side of the output shaft portion and the output side engagement surface are connected via a corner radius. The output shaft portion has a groove that extends linearly in a direction perpendicular to a second virtual plane, which includes the central axis of the output member, and is perpendicular to a first virtual plane passing through the ends of the output engagement surface on both sides in the circumferential direction, and in a direction perpendicular to a second virtual plane, which includes the central axis of the output member, in the portion of the outer peripheral surface on one side in the axial direction in which the phase in the circumferential direction coincides with the output side engagement surface. With respect to the second virtual plane, the groove shape of the cross-section of the groove is approximately U-shaped or approximately C-shaped. Reverse input blocking clutch.

2. The reverse input blocking clutch according to claim 1, wherein the groove shape of the cross-section of the groove portion is substantially U-shaped, and the inner surface of the groove portion is composed of a first inner surface that is a flat surface facing one side in the axial direction, a second inner surface that is a flat surface facing the other side in the axial direction, and a bottom surface that connects the first inner surface and the second inner surface.

3. The reverse input shutoff clutch according to claim 2, wherein the bottom surface is formed by a partially cylindrical concave surface having a single radius of curvature.

4. The bottom surface has a first curved portion having a concave arc-shaped cross-section connected to the first inner surface, and a second curved portion having a concave arc-shaped cross-section connected to the second inner surface. The reverse input blocking clutch according to claim 2.

5. The reverse input shutoff clutch according to claim 4, wherein the bottom surface has a bottom flat portion arranged substantially parallel to the output side engagement surface between the first curved portion and the second curved portion in the axial direction.

6. The reverse input shutoff clutch according to claim 4 or claim 5, wherein the radius of curvature of the first curved surface portion is greater than the radius of curvature of the second curved surface portion.

7. The radius of curvature of the second curved surface is approximately the same as the radius of curvature of the corner R portion. The reverse input interruption clutch according to claim 6.

8. The reverse input blocking clutch according to claim 1, wherein the radial distance from the central axis of the output member to the groove is 0.85 times or more and 1.25 times or less the radial distance from the central axis of the output member to the output-side engagement surface.

9. The reverse input blocking clutch according to claim 1, wherein the axial groove width at the opening of the groove is greater than the axial dimension from the end face on one axial side of the output shaft to the opening of the groove.

10. The output-side engagement surface is composed of two output-side engagement surfaces arranged parallel to each other. The groove portion is composed of two groove portions arranged on opposite sides in the diametrical direction of the outer circumferential surface of the output shaft portion. The reverse input interruption clutch according to claim 1.

11. A small axial gap is provided between the axial end face of the output shaft portion and the axial end face of the engaging element, as described in claim 1.

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