Reverse input blocking clutch

Abstract

This invention provides a reverse input blocking clutch structure that can restrict the axial movement of the engaging element relative to the output member, while also reducing the number of parts and improving ease of assembly. [Solution] The leaf spring 6 has a spring body 48 that elastically braces between the engaging element 5 and the output-side engaging portion 20, a restricting portion 49 that engages with the output-side engaging portion 20 in the axial direction to restrict the relative axial displacement between the output member 4 and the leaf spring 6, and a clamping portion 50 which includes a pair of clamping pieces 56 that clamp the engaging element 5 in the axial direction and restrict the relative axial displacement between the engaging element 5 and the leaf spring 6.

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 blocking the rotational torque reversely input to the output member.

Background Art

[0002] The 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 having a function of transmitting only a part of it to the input member and blocking the rest.

[0003] 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 a 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 a rotational torque is input to the output member, depending on the difference in the mechanism for blocking the rotational torque reversely 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 by the application of the device incorporating the reverse input blocking clutch or the like.

[0004] In the lock-type reverse input blocking clutch described in International Publication No. 2023 / 136149 pamphlet, when a rotational torque is input to the input member, based on the engagement of the input-side engaging portion of the input member with the input-side engaged portion of the engaging element, the engaging element moves in a direction away from the pressed surface provided on the pressed member, and by engaging the output-side engaged portion of the engaging element with the output-side engaging portion of the output member, the rotational torque input to the input member is transmitted to the output member. On the other hand, when a rotational torque is reversely input to the output member, based on the engagement of the output-side engaging portion with the output-side engaged portion, the engaging element moves in a direction approaching the pressed surface, presses the pressing surface against the pressed surface, and frictionally engages the pressing surface with the pressed surface.

Prior Art 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 may unnecessarily increase the force required to switch from a locked state to an unlocked state, or from a semi-locked state to a semi-unlocked state, or cause plastic deformation or wear on the pressing surface and / or the pressed surface.

[0007] In the reverse input blocking clutch described in International Publication No. 2023 / 136149, the axial movement of the engaging element is restricted by using two spacers and a retaining ring, which acts as a stopper member.

[0008] The reverse input blocking clutch described in International Publication No. 2023 / 136149 requires two spacers and a stopper member to restrict the axial movement of the engaging element. This increases the number of parts in the reverse input blocking clutch, leading to disadvantages such as higher parts management costs and increased assembly man-hours.

[0009] The present disclosure aims to realize a reverse input blocking clutch structure that can restrict the axial movement of an engaging element relative to an output member, while reducing the number of parts and improving ease of assembly. [Means for solving the problem]

[0010] A reverse input blocking clutch according to a first aspect of this disclosure comprises a pressed member, an input member, an output member, an engaging element, and a leaf spring.

[0011] The member to be pressed has a surface to be pressed on its inner circumferential surface.

[0012] The input member has an input-side engaging portion located radially inward of the pressed surface and is arranged coaxially with the pressed surface.

[0013] The output member has an output-side engaging portion that is located radially inward from the input-side engaging portion and is arranged coaxially with the pressed surface.

[0014] 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.

[0015] The leaf spring is positioned between the output-side engaging portion and the engaging element, and elastically biases the engaging element in a direction that brings the pressing surface closer to the pressed surface.

[0016] 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.

[0017] The leaf spring comprises a spring body that elastically braces between the engaging element and the output-side engaging portion, a restricting portion that engages axially with the output-side engaging portion to restrict the relative axial displacement between the output member and the leaf spring, and a clamping portion that includes a pair of clamping pieces that clamp the engaging element axially to restrict the relative axial displacement between the engaging element and the leaf spring.

[0018] In the reverse input shutoff clutch of the second aspect of the present disclosure, in the reverse input shutoff clutch of the first aspect of the present disclosure, the output-side engaging portion has an engaging recess on its outer circumferential surface that is recessed compared to adjacent portions on both axial sides and engages with the restricting portion.

[0019] In the reverse input shutoff clutch of the third aspect of the present disclosure, the engaging recess is provided on the outer circumferential surface of the output-side engaging portion, in a portion that is circumferentially offset from the portion that engages with the output-side engaged portion.

[0020] A reverse input shutoff clutch according to a fourth aspect of the present disclosure is a reverse input shutoff clutch according to a third aspect of the present disclosure, wherein the restricting portion is composed of two restricting portions, and the engaging recesses are provided at two radially opposite positions on the outer circumferential surface of the output-side engaging portion.

[0021] A reverse input shutoff clutch according to a fifth aspect of the present disclosure, in which the spring body is positioned away from the output-side engaged portion on both axial sides and elastically pressed against a pair of widthwise plate pieces on the outer circumferential surface of the output-side engaged portion on both axial sides and away from the portion that engages with the output-side engaged portion, and a pair of axial plate pieces connecting the widthwise ends of the pair of widthwise plate pieces and elastically pressed against the radially inner surface of the engaging element, and the two restricting portions have their radially outer ends connected to the widthwise inner ends of the pair of axial plate pieces.

[0022] The reverse input blocking clutch according to the sixth aspect of the present disclosure is the reverse input blocking clutch according to the fifth aspect of the present disclosure, wherein the clamping portion is composed of two clamping portions, and each pair of clamping pieces of the two clamping portions connect the radially inner ends to the outer ends in the width direction of the pair of axial plate pieces.

[0023] In the reverse input blocking clutch according to the seventh aspect of the present disclosure, in the reverse input blocking clutch according to the first aspect of the present disclosure, the output-side engaging portion has, on its outer peripheral surface, an engaging convex portion that protrudes more than the portions adjacent to both axial sides, and the restricting portion has a pair of restricting pieces that axially clamp the engaging convex portion.

[0024] In the reverse input blocking clutch according to the eighth aspect of the present disclosure, in the reverse input blocking clutch according to the seventh aspect of the present disclosure, the engaging convex portion is provided at a portion of the outer peripheral surface of the output-side engaging portion that is circumferentially offset from the portion that engages with the output-side engaged portion.

[0025] In the reverse input blocking clutch according to the ninth aspect of the present disclosure, in the reverse input blocking clutch according to the eighth aspect of the present disclosure, the restricting portion is composed of two restricting portions, and the engaging convex portion is provided at two positions on the outer peripheral surface of the output-side engaging portion that are diametrically opposite.

[0026] In the reverse input blocking clutch according to the tenth aspect of the present disclosure, in the reverse input blocking clutch according to the ninth aspect of the present disclosure, the spring body is disposed at positions axially offset from both sides of the output-side engaged portion, and has a pair of width-direction plate pieces that are elastically pressed against portions of the outer peripheral surface of the output-side engaging portion that are axially offset from both sides of the output-side engaged portion, and a pair of axial plate pieces that connect the ends on both width-direction sides of the pair of width-direction plate pieces and are elastically pressed against the radially inner surface of the engaging element. Each pair of restricting pieces of the two restricting portions connect the radially outer ends to the outer ends in the width direction of the pair of axial plate pieces.

[0027] In the reverse input blocking clutch according to the 11th aspect of the present disclosure, in the reverse input blocking clutch according to the 10th aspect of the present disclosure, the clamping portion is composed of two clamping portions, and each of the pair of clamping pieces of the two clamping portions connects the radially inner end portion to the radially inner end portion of each of the pair of regulating pieces of the two regulating portions.

[0028] The reverse input blocking clutch according to the 12th aspect of the present disclosure is the reverse input blocking clutch according to any one of the 1st to 11th aspects of the present disclosure, wherein the engaging element has a convex curved surface portion on at least one of the portions that engage with the input-side engaging portion among the input-side engaged portions and the portions that engage with the output-side engaging portion among the output-side engaged portions.

Advantages of the Invention

[0029] According to the reverse input blocking clutch of one aspect of the present disclosure, the number of parts can be reduced and the assemblability can be improved.

Brief Description of the Drawings

[0030] [Figure 1] FIG. 1 is a cross-sectional view of the reverse input blocking clutch of the first example of the embodiment of the present disclosure. [Figure 2] FIG. 2 is an end view seen from the input member side with the input member removed from the reverse input blocking clutch of the first example. [Figure 3] FIG. 3 is a cross-sectional view taken along the line X-X of FIG.  1 showing the state where rotational torque is input to the input member with the leaf spring omitted. [Figure 4] FIG. 4 is a cross-sectional view taken along the line X-X of FIG. 1 showing the state where rotational torque is input to the output member with the holding member and the biasing member omitted. [Figure 5] FIG. 5 is a perspective view showing a part of the members removed from the reverse input blocking clutch of the first example. [Figure 6] FIG. 6 is an exploded perspective view of the reverse input blocking clutch of the first example. [Figure 7] FIG. 7 is a view showing the output member of the reverse input blocking clutch of the first example removed, where FIG. 7(A) is a plan view and FIG. 7(B) is a side view. [Figure 8] Figure 8 shows the leaf spring of the reverse input blocking clutch in the first example, where Figure 8(A) is a top view, Figure 8(B) is a front view, and Figure 8(C) is a side view. [Figure 9] Figure 9 is a diagram similar to Figure 5, showing some components extracted from a reverse input shutoff clutch of a second embodiment of the present disclosure. [Figure 10] Figure 10 is a perspective view showing the output member of the second example of the reverse input blocking clutch. [Figure 11] Figure 11 is a diagram similar to Figure 7, showing the output member of the reverse input blocking clutch in the second example. [Figure 12] Figure 12 is a diagram similar to Figure 8, showing the leaf spring of the reverse input blocking clutch in the second example. [Modes for carrying out the invention]

[0031] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to Figures 1 to 8(C).

[0032] 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 member 3 side (the right side in Figures 1, 7(A), and 7(B)), and the other axial side refers to the output member 4 side (the left side in Figures 1, 7(A), and 7(B)).

[0033] The direction of the pressing surface 37 of the engaging element 5 relative to the pressed surface 7 is defined as the first direction (up and down direction in Figures 2 to 4), 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 2 to 4). For the engaging element 5, the direction coinciding with the first direction is defined as its radial direction (direction indicated by arrow α in Figure 3), and the direction coinciding with the second direction is defined as its width direction (direction indicated by arrow β in Figure 3). Furthermore, with respect to the width direction of the engaging element 5, the inside refers to the center side of the engaging element 5 in the width direction, and the outside refers to both sides of the engaging element 5 in the width direction.

[0034] With respect to the leaf spring 6, the radial and width directions refer to the radial and width directions of the engaging element 5 when the leaf spring 6 is positioned between the output-side engaging portion 20 and the engaging element 5.

[0035] <Explanation of the structure of the reverse input blocking clutch> The reverse input blocking clutch 1 comprises a pressed member 2, an input member 3, an output member 4, an engaging element 5, and a leaf spring 6. The reverse input blocking clutch 1 transmits the rotational torque input to the input member 3 to the output member 4, while the reverse input blocking function either completely blocks the rotational torque that is reverse input to the output member 4 and does not transmit it to the input member 3, or transmits only a portion of it to the input member 3 and blocks the rest.

[0036] In particular, the reverse input blocking clutch 1 in this example is characterized in that the leaf spring 6 has a spring body 48 that elastically braces between the engaging element 5 and the output-side engaging portion 20, a restricting portion 49 that engages with the output-side engaging portion 20 in the axial direction to restrict the relative axial displacement between the output member 4 and the leaf spring 6, and a clamping portion 50 that includes a pair of clamping pieces 56 that clamp the engaging element 5 in the axial direction to restrict the relative axial displacement between the engaging element 5 and the leaf spring 6.

[0037] [Subjected component] The member to be pressed 2 has a surface to be pressed 7 on its inner circumferential surface.

[0038] The pressed member 2 is supported and fixed to a fixed part that does not rotate even when the reverse input blocking clutch 1 is in use, or it is integrally provided with the fixed part so that its rotation is restrained.

[0039] The pressed surface 7 constitutes the surface that contacts the pressing surface 37 of the engaging element 5 when the engaging element 5 moves radially outward, which is the direction towards the pressed surface 7. The shape of the pressed member 2 is not limited as long as it is configured to have the pressed surface 7 on its inner circumferential surface. The pressed surface 7 is annular when viewed from the axial direction. In addition, although not limited to this, in this example the pressed surface 7 has a cylindrical shape in which the inner diameter does not change with respect to the axial direction.

[0040] The input-side engaging portion 14 of the input member 3 and the output-side engaging portion 20 of the output member 4 are positioned radially inward of the pressed surface 7. The input-side engaging portion 14, the output-side engaging portion 20, and the engaging element 5 are rotatable radially inward of the pressed surface 7.

[0041] When the pressed member 2 is supported and fixed to the fixed portion, known means can be used. In this example, the pressed member 2 includes a housing element 8 as an optional element supported and fixed to the fixed portion.

[0042] 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.

[0043] Furthermore, the housing element 8 has an inwardly projecting flange portion 12 at the axial end of the small-diameter cylindrical surface portion 10 that protrudes radially inward, and has screw holes 13 opening at multiple locations in the circumferential direction on the side surface on the axial side. The pressed member 2 in this example is supported and fixed to the fixing portion by screwing a bolt, which is inserted through a through hole provided in the fixing portion, into the screw holes 13.

[0044] 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.

[0045] [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.

[0046] The input member 3 is connected to an input-side mechanism such as an electric motor, 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 component from the output shaft and can be fixed coaxially to the output shaft. Additionally, the input member 3 has an input shaft portion 15 that is coaxial with the output shaft, and this input shaft portion can be rotatably supported with respect to the fixed portion.

[0047] The input-side engaging portion 14 is provided on a part of the input member 3 that is radially outward from the center of rotation and has a portion that engages, specifically contacts, with the input-side engaged portion 38 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 of the input-side engaged portion as the input member 3 or engaging element 5 rotates.

[0048] The outer circumferential surface of the input-side engaging portion 14 can have any configuration as long as it engages with the input-side engaged portion 38. For example, it can have an end face shape such as a roughly fan-shaped, roughly trapezoidal, or arched shape, where the circumferential width increases towards the radially outward direction when viewed from the axial direction. From the standpoint of reducing the manufacturing cost of the input member 3, it is preferable that the outer circumferential surface of the input-side engaging portion 14 consists only of a flat radially inward surface 16 and a partially cylindrical radially outward surface 17 centered on the central axis of the input member 3.

[0049] In this example, the outer circumferential surface of the input-side engaging portion 14 consists only of a flat radial inner surface 16 and a partially cylindrical radial outer surface 17. That is, the input-side engaging portion 14 has an arc-shaped end face when viewed from the axial direction. The radial inner surface 16 and the radial outer surface 17 are connected by a pointed edge 18. However, the radial inner surface 16 and the radial outer surface 17 can also be connected by chamfered portions such as corner chamfers or rounded chamfers.

[0050] Therefore, in the reverse input blocking clutch 1 of this example, when manufacturing the input member 3 having the input side engaging portion 14, it is not necessary to perform machining on the connection between the radial inner surface 16 and the radial outer surface 17 of the input side engaging portion 14. For example, the input member 3 can be manufactured by forging a metal material to form its outer shape, and then performing finishing processes such as grinding as needed. This reduces the manufacturing cost of the input member 3. However, the input member 3 can also be manufactured by machining a metal material, including cutting.

[0051] In this example, the input member 3 has an input shaft portion 15 and an input flange portion 19, in addition to the input-side engaging portion 14.

[0052] The input shaft portion 15 has a cylindrical or cylindrical shape, depending on the shape of the output shaft of the input-side mechanism. In this example, the input shaft portion 15 has a cylindrical shape.

[0053] The input flange portion 19 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. The input flange portion 19 can be fixed to the output shaft of the input-side mechanism or to the input shaft portion 15, or it can be integrally formed with it. In this example, the input flange portion 19 protrudes radially outward from the outer circumferential surface of the other axial end of the input shaft portion 15 over its entire circumference.

[0054] The input-side engaging portion 14 protrudes axially toward the other side from the portion of the input flange portion 19 that is radially outward from the center of rotation on the other axial side.

[0055] 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.

[0056] In the reverse input blocking clutch 1 of 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 19, and are spaced apart from each other with respect to the radial direction of the input member 3.

[0057] The input member 3 can be rotatably supported by the pressed member 2 or the fixed portion. In this example, the input member 3 is positioned coaxially with the pressed surface 7 by the input shaft portion 15 being rotatably supported inside the fixed portion by a radial bearing (not shown).

[0058] [Output components] The output member 4 has an output-side engaging portion 20 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.

[0059] The output member 4 is connected to an output-side mechanism such as a reduction gear mechanism, and is configured to output rotational torque to the output-side mechanism as it rotates. Specifically, the output member 4 can be made up of the input shaft of the output-side mechanism, or it can be made up as a separate member from the input shaft and fixed coaxially to the input shaft.

[0060] The output-side engaging portion 20 has a portion that engages with the output-side engaged portion 39 of the engaging element 5. This engaging portion is located radially inward from the input-side engaging portion 14 and radially outward from the central axis of the output member 4, and is positioned to engage with the output-side engaged portion 39 of the engaging element 5. The output-side engaging portion 20 is configured to engage (contact) its outer circumferential surface with the output-side engaged portion 39 as the output member 4 or the engaging element 5 rotates. In this example, the axial width of the output-side engaging portion 20 is greater than the axial width of the engaging element 5.

[0061] The output-side engaging portion 20 has a cam function. The distance from the rotational center axis of the output member 4 to the outer circumferential surface of the output-side engaging portion 20, which engages with the output-side engaged portion 39, is not constant in the circumferential direction. As a result, when rotational torque is input in reverse to the output member 4, the output-side engaging portion 20 can press the engaging element 5 in the radial direction of the engaging element 5, which is the first direction, as the output member 4 rotates.

[0062] The number of parts of the output-side engaging portion 20 that engage with the output-side engaged portion 39 is determined according to the number of engaging elements 5. When the engaging element 5 is composed of multiple engaging elements 5, the output-side engaging portion 20 is also configured to have multiple engaging parts. In this example, the output-side engaging portion 20 is configured to have two parts that engage with the output-side engaged portion 39, corresponding to the number of engaging elements 5. However, even when there is only one engaging element 5, it is possible to adopt a structure similar to this example.

[0063] The outer circumferential surface of the output-side engaging portion 20 can adopt any configuration as long as the output-side engaging portion 20 has a cam function, and its shape is appropriately set according to the number of portions of the output-side engaging portion 20 that engage with the output-side engaged portion 39. When there are portions that engage with two output-side engaged portions 39, the output-side engaging portion 20 can be, for example, a roughly rectangular or roughly oval, parallelogram, or trapezoid shape. However, from the viewpoint of reducing the manufacturing cost of the output member 4, it is preferable that the outer circumferential surface of the output member 4 has a flat surface portion 22 in the portion that engages with the output-side engaged portion 39, and it is even more preferable that it is composed of a flat surface portion 22 and a partially cylindrical surface portion 23 centered on the central axis of the output member 4. In this example, the portion of the flat surface portion 22 located in the axial middle and widthwise middle constitutes the portion that engages with the output-side engaged portion 39.

[0064] In this example, the outer surface of the output-side engaging portion 20 is composed of two parallel flat surfaces 22 and two partially cylindrical surfaces 23. The output-side engaging portion 20 is symmetrical with respect to a virtual plane that passes through the rotational axis of the output member 4 and is perpendicular to the two flat surfaces 22. Furthermore, the output-side engaging portion 20 is symmetrical with respect to a virtual plane that passes through the rotational axis of the output member 4 and is parallel to the two flat surfaces 22. That is, the output-side engaging portion 20 has a shape that is twice symmetrical with respect to the central axis of the output member 4. The flat surfaces 22 and the partially cylindrical surfaces 23 are connected by pointed edges 27. However, the flat surfaces 22 and the partially cylindrical surfaces 23 can also be connected by chamfered portions such as corner chamfers and rounded chamfers.

[0065] Therefore, when manufacturing the output member 4 having the output-side engaging portion 20, it is not necessary to perform machining on the portion of the output-side engaging portion 20 that engages with the output-side engaged portion 39. For example, the output member 4 can be manufactured by forging a metal material to form its outer shape, and then performing finishing processes such as grinding as needed. This reduces the manufacturing cost of the output member 4. However, the output member 4 can also be manufactured by machining a metal material, including cutting.

[0066] In this example, the reverse input blocking clutch 1 utilizes a leaf spring 6 as a structure to restrict the axial movement of the engaging element 5 relative to the output member 4. Therefore, the output-side engaging portion 20 has a portion that engages axially with the restricting portion 49 of the leaf spring 6, and this engaging portion engages axially with the restricting portion 49. This structure makes it possible to restrict the relative axial displacement between the output member 4 and the leaf spring 6.

[0067] The number of parts of the output-side engaging portion 20 that engage with the restricting portion 49 in the axial direction is determined according to the number of leaf springs 6. When the leaf spring 6 is composed of multiple leaf springs 6, the output-side engaging portion 20 is also configured to have multiple of the aforementioned engaging parts. Furthermore, when each of the leaf springs 6 has multiple restricting portions 49, the output-side engaging portion 20 is also configured to have multiple of the aforementioned engaging parts. In this example, the leaf spring 6 is composed of two leaf springs 6, and each of the two leaf springs 6 has two restricting portions 49, so the output-side engaging portion 20 has parts that engage with four restricting portions 49 in the axial direction.

[0068] The portion of the output-side engaging portion 20 that engages with the restricting portion 49 in the axial direction can be configured in any way, as long as it can restrict the relative axial displacement between the output member 4 and the leaf spring 6. For example, the engaging portion can be configured as an engaging recess 24 provided on the outer circumferential surface of the output-side engaging portion 20, recessed from adjacent portions on both axial sides, and the restricting portion 49 can be positioned inside the engaging recess 24. Alternatively, the engaging portion can be configured as an engaging projection provided on the outer circumferential surface of the output-side engaging portion 20, protruding from adjacent portions on both axial sides, and the engaging projection can be axially clamped by a pair of restricting pieces constituting the restricting portion.

[0069] The portion of the output-side engaging portion 20 that engages with the restricting portion 49 in the axial direction is composed of a surface facing one side in the axial direction and a surface facing the other side in the axial direction. These surfaces are composed of the axially opposing side surfaces of the inner surface of the engaging recess 24, or the axially outward facing side surfaces of the engaging protrusion. The portion of the output-side engaging portion 20 that engages with the restricting portion 49 in the axial direction can be provided at any position, but it is preferable that it be provided on the outer circumferential surface of the output-side engaging portion 20, away from the portion that engages with the output-side engaged portion 39, in order to prevent interference with the engaging element 5.

[0070] In this example, the engaging recess 24 is provided on the axial intermediate portion of each of the two partial cylindrical surface portions 23, which are located on the outer circumferential surface of the output-side engaging portion 20 and are circumferentially separated from the two flat surface portions 22 that engage with the output-side engaged portion 39, on both axially adjacent portions. The axial inner surfaces of the engaging recess 24 are parallel to each other. Specifically, the engaging recess 24 has a substantially rectangular cross-sectional shape.

[0071] The output-side engaging portion 20 is located radially inward of the two input-side engaging portions 14, and is positioned between the output-side engaged portions 39 of the two engaging elements 5.

[0072] The output member 4 can be rotatably supported by the pressed member 2 or the fixed portion via a rolling bearing or the like.

[0073] In this example, the output member 4 has, in addition to the output-side engaging portion 20, an output shaft portion 28, an output flange portion 29, and a small-diameter shaft portion 30.

[0074] The output shaft portion 28 is formed by the input shaft of the output mechanism, or, as in this example, if the output member 4 is configured as a separate component from the input shaft, it can be fixed coaxially to the input shaft, etc. In this example, the output shaft portion 28 has a stepped cylindrical shape.

[0075] The output flange portion 29 protrudes radially outward from the outer circumferential surface of one axial end of the output shaft portion 28 along its entire circumference. The output flange portion 29 is an element for attaching the output member 4 to the pressed member 2 or the fixed portion so that it can rotate and cannot be displaced in the axial direction.

[0076] The output-side engaging portion 20 protrudes from the center of the end face on one axial side of the output shaft portion 28 toward the one axial side.

[0077] The small-diameter shaft portion 30 has a cylindrical shape and protrudes in the axial direction from the center of the end face on one axial side of the output-side engaging portion 20. The small-diameter shaft portion 30 is an element that ensures the coaxiality of the output member 4 with respect to the input member 3.

[0078] In this example, the output member 4 is rotatably supported radially inward of the housing element 8 of the pressed member 2 by a radial rolling bearing 31. The outer ring 32 of the radial rolling bearing 31 is fitted snugly into the small-diameter cylindrical surface portion 10 of the housing element 8 and is axially clamped between one axial side surface of the inward flange portion 12 and a retaining ring 33a that is locked to one axial end of the small-diameter cylindrical surface portion 10. The inner ring 34 of the radial rolling bearing 31 is fitted snugly onto one axial end of the output shaft portion 28 and is axially clamped between the other axial side surface of the output flange portion 29 and a retaining ring 33b that is locked to the outer circumferential surface of the axial intermediate portion of the output shaft portion 28.

[0079] In the illustrated example, the radial rolling bearing 31 is a ball bearing using balls as rolling elements 35. However, the radial rolling bearing for supporting the output member 4 can also be constructed using a tapered roller bearing with tapered rollers as rolling elements or a roller bearing with cylindrical rollers.

[0080] Furthermore, the small-diameter shaft portion 30 of the output member 4 is supported by a sliding bearing (sleeve) 36 inside the input member 3, allowing for free relative rotation with respect to the input member 3.

[0081] [Engagement element] The engaging element 5 has a pressing surface 37 facing the pressed surface 7, an input-side engaged portion 38 that can engage with the input-side engaging portion 14, and an output-side engaged portion 39 that can engage with the output-side engaging portion 20, and is arranged to allow radial movement of the engaging element 5.

[0082] 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 38, and transmits the rotational torque input to the input member 3 to the output member 4 by engaging the output-side engaged portion 39 with the output-side engaging portion 20. Conversely, when rotational torque is input in reverse to the output member 4, the engaging element 5 presses the pressing surface 37 against the pressed surface 7 based on the output-side engaging portion 20 engaging with the output-side engaged portion 39, thereby frictionally engaging the pressing surface 37 with the pressed surface 7.

[0083] The engaging element 5 can consist of one engaging element 5 or two or more engaging elements 5, as long as it has the above configuration.

[0084] 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.

[0085] 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 cutting. From the standpoint of reducing the manufacturing cost of the engaging element 5, it is preferable that the engaging element 5 be manufactured by pressing. In this example, the engaging element 5 is a press-formed product of a metal sheet manufactured by pressing.

[0086] The shape of the engaging element 5 is arbitrary as long as it has a pressing surface 37, an input-side engaged portion 38, and an output-side engaged portion 39, and can perform the functions described above. In this example, since the engaging element 5 is composed of two engaging elements 5, each engaging element 5 has a substantially semicircular end face shape when viewed from the axial direction and has a shape that is symmetrical with respect to the width direction.

[0087] The engaging element 5 may optionally have convex curved surfaces 40 and 41 on at least one of the parts of the input-side engaged portion 38 that engages with the input-side engaging portion 14, and the output-side engaged portion 39 that engages with the output-side engaging portion 20. This makes it possible to bring the input-side engaged portion 38 into contact with the radially inner surface 16 of the input-side engaging portion 14, and to bring the output-side engaged portion 39 into contact with the flat surface portion 22 of the output-side engaging portion 20 when the reverse input blocking clutch 1 is operated.

[0088] In other words, the engaging element 5 may have a convex curved surface portion 40 on the part of the input-side engaged portion 38 that engages with the input-side engaging portion 14. Each input-side engaged portion 38 has a portion that engages with two input-side engaging portions 14. Therefore, the convex curved surface portion 40 is provided at two locations on the input-side engaged portion 38.

[0089] Additionally or alternatively, the engaging element 5 may have a convex curved surface portion 41 on the portion of the output-side engaged portion 39 that engages with the output-side engaging portion 20. Each output-side engaged portion 39 has portions that engage with two output-side engaging portions 20. Therefore, the convex curved surface portion 41 is provided at two locations on the output-side engaged portion 39.

[0090] In this example, the engaging element 5 has a convex curved surface portion 40 in the portion of the input-side engaged portion 38 that engages with the input-side engaging portion 14, and a convex curved surface portion 41 in the portion of the output-side engaged portion 39 that engages with the output-side engaging portion 20. Therefore, with the reverse input shutoff clutch 1 of this example, the contact pressure at the contact points between the input member 3 and the output member 4 and the engaging element 5 can be kept low.

[0091] The pressing surface 37 is provided on the radially outer surface of the engaging element 5 facing the pressed surface 7. In this example, the pressing surface 37 is composed of two pressing surfaces 37 provided 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 37 is composed of a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface 7.

[0092] Of the radially outer surface of the engaging element 5, the portion that is circumferentially away from the two pressing surfaces 37 is located radially inward from a virtual circle that is centered on the central axis of the input member 3 and tangent to the two pressing surfaces 37, when viewed from the axial direction. In other words, when the two pressing surfaces 37 are in contact with the surface to be pressed 7, the portion that is circumferentially away from the two pressing surfaces 37 does not come into contact with the surface to be pressed 7.

[0093] The pressing surface 37 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 37 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 means of adhesion or bonding.

[0094] In this example, the input-side engaged portion 38 is provided in the radially intermediate portion of the widthwise center of the engaging element 5. More specifically, although not limited to this, the input-side engaged portion 38 has a substantially arc-shaped opening when viewed from the axial direction and 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.

[0095] The input-side engaged portion 38 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 38, there are gaps between the input-side engaged portion 14 and the inner surface of the input-side engaged portion 38 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 38 in the rotational direction of the input member 3, and the input-side engaged portion 38 can be displaced relative to the input-side engaged portion 14 in the radial direction of the engaging element 5.

[0096] The convex curved surface portion 40 is provided on the radially inner surface 42 of the inner surface of the input-side engaged portion 38, which faces radially outward, in the portion that engages with the input-side engaged portion 14, so as to be convex toward the input-side engaged portion 14. The convex curved surface portion 40 is provided at two locations on the radially inner surface 42: the portion that engages with the input-side engaged portion 14 when the input member 3 rotates to one side relative to the engager 5, and the portion that engages with the input-side engaged portion 14 when the input member 3 rotates to the other side relative to the engager 5.

[0097] Specifically, the radial inner surface 42 of the input-side engaged portion 38 is provided with a convex portion 43 that protrudes radially outward from the adjacent portions on both sides in the second direction, and two convex curved portions 40 are provided at two locations in the second direction of the convex portion 43.

[0098] In this example, the convex curved surface portion 40 is provided at both ends of the convex curved surface portion 43 in the second direction. The convex curved surface portion 43 also has a connecting surface portion 46 in the second direction intermediate portion between the two convex curved surface portions 40, which connects the two convex curved surface portions 40 and is formed by a flat surface perpendicular to the first direction.

[0099] The cross-sectional shape and radius of curvature of the convex curved surface portion 40 are not particularly limited, as long as they can prevent the contact pressure at the contact point with the input-side engaging portion 14 from becoming excessive. For example, the cross-sectional shape of the convex curved surface portion 40 can be approximately arc-shaped, approximately elliptical, etc. The cross-sectional shape and radius of curvature of the convex curved surface portion 40 can be determined by experiment, simulation, etc.

[0100] In this example, the radially outer surface 44 of the inner surface of the input-side engaged portion 38, 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 45 connecting the radially inner surface 42 and the radially outer surface 44 is composed of a partially cylindrical concave curved surface.

[0101] The output-side engaged portion 39 is provided at the center of the width direction on the radially inner surface of the engaging element 5. The shape of the output-side engaged portion 39 is not limited as long as it is configured to engage with the output-side engaged portion 20. In this example, the output-side engaged portion 39 is provided at the center of the width direction on the radially inner surface of the engaging element 5, so as to protrude radially inward from the portions adjacent to it on both sides in the width direction.

[0102] The convex curved portion 41 is provided at two locations within the output-side engaging portion 39: the portion that engages with the output-side engaging portion 20 when the output member 4 rotates to one side, and the portion that engages with the output-side engaging portion 20 when the output member 4 rotates to the other side relative to the engaging element 5. The convex curved portion 41 is provided so as to be convex toward the output-side engaging portion 20.

[0103] In this example, the convex curved surface portion 41 is provided at both ends of the output-side engaged portion 39 in the width direction (second direction). The output-side engaged portion 39 also has a connecting surface portion 47 in the width direction intermediate between the two convex curved surface portions 41, which connects the two convex curved surface portions 41 and is composed of a flat surface perpendicular to the radial direction.

[0104] The cross-sectional shape and radius of curvature of the convex curved surface portion 41 are not particularly limited, as long as they can prevent the contact pressure at the contact point with the output-side engaging portion 20 from becoming excessive. For example, the cross-sectional shape of the convex curved surface portion 41 can be approximately arc-shaped, approximately elliptical, etc. The cross-sectional shape and radius of curvature of the convex curved surface portion 41 can be determined by experiment, simulation, etc.

[0105] In this example, the engaging element 5 is provided with convex curved surfaces 40 and 41 to reduce the contact pressure at the contact points between the input member 3 and the output member 4 and the engaging element 5. Therefore, compared to the case where the convex curved surfaces are provided by machining the contact points of the input member 3 and the output member 4 with the engaging element 5, manufacturing costs can be reduced.

[0106] Furthermore, in this example, the engaging element 5, which has convex curved surfaces 40 and 41 at the contact points with the input member 3 and the output member to reduce contact pressure, is manufactured by press stamping. This also helps to reduce manufacturing costs.

[0107] [Leaf spring] The leaf spring 6 is positioned between the output-side engaging portion 20 and the engaging element 5, and elastically biases the engaging element 5 in a direction that brings the pressing surface 37 closer to the pressed surface 7.

[0108] The leaf spring 6 has a spring body 48 that elastically braces between the engaging element 5 and the output-side engaging portion 20 (elastically pressing the engaging element 5 and the output-side engaging portion 20 in a direction that separates them from each other), a restricting portion 49 that engages with the output-side engaging portion 20 in the axial direction to restrict the relative axial displacement between the output member 4 and the leaf spring 6, and a clamping portion 50 which includes a pair of clamping pieces 56 that clamp the engaging element 5 in the axial direction and restrict the relative axial displacement between the engaging element 5 and the leaf spring 6.

[0109] In other words, the leaf spring 6 has the function of elastically biasing the engaging element 5 by the spring body 48 in a direction that brings the pressing surface 37 closer to the pressed surface 7, as well as the function of restricting the relative axial displacement between the output member 4 and the leaf spring 6 by the restricting portion 49, and the function of restricting the relative axial displacement between the engaging element 5 and the leaf spring 6 by the clamping portion 50. That is, the leaf spring 6 ensures the axial positioning of the engaging element 5 with respect to the output member 4.

[0110] The function of restricting the relative axial displacement between the output member 4 and the leaf spring 6 is achieved by engaging the restricting portion 49 with the output-side engaging portion 20 in the axial direction, and the function of restricting the relative axial displacement between the engaging element 5 and the leaf spring 6 is achieved by clamping the engaging element 5 in the axial direction with a pair of clamping pieces 56 that constitute the clamping portion 50.

[0111] According to the reverse input blocking clutch 1 in this example, dedicated parts, namely spacers and stopper members, are not required to restrict the axial movement of the engaging element 5 relative to the output member 4. This reduces the number of parts, thereby lowering parts management costs and / or reducing assembly man-hours.

[0112] The leaf spring 6 is manufactured by pressing and bending an elastic metal sheet, such as a spring steel sheet or a stainless steel sheet.

[0113] The shape and number of leaf springs 6 can be any shape and number, as long as they can press all the engaging elements 5 in a direction that brings the pressing surface 37 closer to the pressed surface 7, and can be positioned axially with respect to the output member 4.

[0114] In this example, the leaf spring 6 is composed of two leaf springs 6, corresponding to the number of engaging elements 5, and each leaf spring 6 functions as a leaf spring 6.

[0115] The spring body 48 elastically braces the engaging element 5 between the engaging element 5 and the output-side engaging portion 20, thereby elastically biasing the engaging element 5 in a direction that brings its pressing surface 37 closer to the pressed surface 7, i.e., radially outward. As a result, in a neutral state where no torque is applied to either the input member 3 or the output member 4, the pressing surface 37 of the engaging element 5 contacts the pressed surface 7. Furthermore, it suppresses rattle between the output-side engaging portion 20 of the output member 4 and the output-side engaged portion 39 of the engaging element 5, enabling immediate locking when rotational torque is input in reverse to the output member 4.

[0116] The spring body 48 can adopt any configuration as long as it has the functions described above.

[0117] For example, the spring body 48 can be configured to elastically brace between the radially inner surface of the engaging element 5 and the outer circumferential surface of the output-side engaging portion 20. Specifically, the spring body 48 has a pair of widthwise plate pieces 51 positioned away from the output-side engaged portion 39 on both axial sides and elastically pressed against the outer circumferential surface of the output-side engaging portion 20 on both axial sides from the portion that engages with the output-side engaged portion 39, and a pair of axial plate pieces 52 connecting the widthwise ends of the pair of widthwise plate pieces 51 and elastically pressed against the radially inner surface of the engaging element 5, and can be configured as a substantially rectangular frame overall.

[0118] In this example, the spring body 48 has a pair of widthwise plate pieces 51 and a pair of axial plate pieces 52, and is configured to elastically brace between the radially inner surface of the engaging element 5 and the flat surface portion 22 of the output-side engaging portion 20. The pair of widthwise plate pieces 51 are elastically pressed against both axial sides of the flat surface portion 22 of the output-side engaging portion 20, and the pair of axial plate pieces 52 are elastically pressed against the portion of the radially inner surface of the engaging element 5 that is located widthwise outward from the portion provided with the convex curved surface portion 41.

[0119] The restricting portion 49 is configured to engage with the output-side engaging portion 20 in the axial direction to restrict the relative axial displacement between the output member 4 and the leaf spring 6. Specifically, the restricting portion 49 has a surface facing one side in the axial direction and a surface facing the other side in the axial direction. By bringing the surface of the restricting portion 49 facing one side in the axial direction into contact with or opposite the surface of the output-side engaging portion 20 facing the other side in the axial direction, and by bringing the surface of the restricting portion 49 facing the other side in the axial direction into contact with or opposite the surface of the output-side engaging portion 20 facing one side in the axial direction, the relative axial displacement between the output member 4 and the leaf spring 6 is restricted.

[0120] The restricting portion 49 can adopt any configuration as long as it has the above configuration. That is, the arrangement and shape of the restricting portion 49 are determined according to the arrangement and shape of the parts that engage with the restricting portion 49 in the axial direction, such as the engaging recess 24 and engaging protrusion provided on the output side engaging portion 20 of the output member 4. Specifically, the restricting portion 49 is provided on a part of the spring body 48, or on a part connected to the spring body 48, and is composed of an axial side that lightly contacts or faces the axial side of the part of the output side engaging portion 20 that engages with the restricting portion 49 in the axial direction.

[0121] Furthermore, the restricting portion 49 may consist of one restricting portion 49 or two or more restricting portions 49. In addition, depending on the portion of the output-side engaging portion 20 that engages with the restricting portion 49 in the axial direction, the restricting portion 49 may also be composed of a pair of restricting pieces spaced apart in the axial direction.

[0122] In this example, the restricting portion 49 is composed of two restricting portions 49 that engage with two engaging recesses 24 provided on the output-side engaging portion 20. Since the engaging recesses 24 are provided in the axial intermediate portion of the partial cylindrical surface portion 23 of the output-side engaging portion 20, each restricting portion 49 connects its radially outer end to the widthwise inner end of a pair of axial plate pieces 52. In other words, in this example, the restricting portions 49 are positioned radially inward from the spring body 48.

[0123] In this example, each restricting portion 49 has an end face shape that is curved in a roughly U-shape when viewed from the axial direction. However, the restricting portion 49 may also have an end face shape that is roughly J-shaped, roughly L-shaped, roughly cylindrical, or roughly partially cylindrical when viewed from the axial direction.

[0124] More specifically, each restricting portion 49 has an outer plate portion 53 extending inward in the width direction from the axial middle portion of the widthwise inner end of the axial plate piece 52, a connecting plate portion 54 extending radially inward from the widthwise inner end of the outer plate portion 53, and an inner plate portion 55 extending outward in the width direction from the radially inner end of the connecting plate portion 54.

[0125] In this example, with the leaf spring 6 positioned between the output-side engaging portion 20 and the engaging element 5, the connecting plate portion 54 is positioned inside the engaging recess 24. In this state, one axial end face of the connecting plate portion 54 is in light contact or close proximity to one axial side of the inner surface of the engaging recess 24, and the other axial end face of the connecting plate portion 54 is in light contact or close proximity to the other axial side of the inner surface of the engaging recess 24. This restricts the relative axial displacement between the output member 4 and the leaf spring 6.

[0126] In this example, with the leaf spring 6 positioned between the output-side engaging portion 20 and the engaging element 5, the inner surface in the width direction of the connecting plate portion 54 is in light contact with or in close proximity to the bottom surface of the inner surface of the engaging recess 24. This ensures that the leaf spring 6 is positioned in the width direction relative to the output-side engaging portion 20.

[0127] The clamping portion 50 is configured to clamp the engaging element 5 in the axial direction with a pair of clamping pieces 56, thereby restricting the relative axial displacement between the engaging element 5 and the leaf spring 6. Specifically, the axial relative displacement between the engaging element 5 and the leaf spring 6 is restricted by bringing the axial end face of one of the axial clamping pieces 56 to contact or face the axial side of the engaging element 5, and by bringing the axial end face of the other clamping piece 56 to contact or face the axial side of the engaging element 5.

[0128] The clamping portion 50 can adopt any configuration as long as it has the above configuration. That is, the arrangement and shape of the clamping portion 50 are determined according to the structure of the engaging element 5, the arrangement relationship between the spring body 48 and the engaging element 5, the arrangement and shape of the restricting portion 49, etc. Since the engaging element 5 is arranged radially outward of the output-side engaging portion 20, the clamping portion 50 is provided on a part of the spring body 48 or a part connected to the restricting portion 49, and is arranged radially outward from the spring body 48 so that it can face the axial side surface of the engaging element 5 regardless of the radial (first direction) movement of the engaging element 5.

[0129] For example, a pair of clamping pieces 56 can be configured to connect their radially inner ends to the widthwise outer ends of a pair of axial plate pieces 52. Alternatively, if the restricting portion has a pair of restricting pieces, a pair of clamping pieces can be configured to connect their radially inner ends to the radially inner ends of the pair of restricting pieces. The shape of the pair of clamping pieces can be any shape as long as it can clamp the engaging element 5 in the axial direction. For example, each of the clamping pieces can have an end face shape such as a roughly U-shape, a roughly J-shape, a roughly L-shape, a roughly cylindrical shape, or a roughly partial cylindrical shape when viewed from the axial direction.

[0130] Furthermore, the clamping portion 50 can be composed of one clamping portion 50, or it can be composed of two or more clamping portions 50.

[0131] In this example, the clamping portion 50 is composed of two clamping portions 50 that clamp the engaging element 5 at two positions spaced apart in the width direction in the axial direction. Each pair of clamping pieces 56 constituting the clamping portion 50 has its radially inner end connected to the widthwise outer and axially oriented ends of the axial plate piece 52. In this example, the pair of clamping pieces 56 have an end face shape that is curved to be approximately partially cylindrical when viewed from the axial direction.

[0132] In the reverse input blocking clutch 1 of this example, the relative axial displacement between the output member 4 and the leaf spring 6 is restricted, and the relative axial displacement between the engaging element 5 and the leaf spring 6 is also restricted. In other words, the leaf spring 6, which is a single element, makes it possible to restrict the axial movement of the engaging element 5 relative to the output member 4. Furthermore, the leaf spring 6 can be easily manufactured from sheet metal by punching and bending.

[0133] <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 3 and 4. Note that Figures 3 and 4 omit the leaf spring 6 and exaggerate the radial gap between the input member 3 and the output member 4 and the two engaging elements 5.

[0134] 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 3, the input-side engaging portion 14 rotates inside the input-side engaged portion 38 in the direction of rotation of the input member 3 (counterclockwise in the example of Figure 3).

[0135] This reduces the gap between the radially inner surface 16 of the input-side engaging portion 14 and the radially inner surface 42 of the input-side engaged portion 38, causing the radially inner surface 16 of the input-side engaging portion 14 to come into contact with the radially inner surface 42 of the input-side engaged portion 38.

[0136] In this example, the radially inner surface 16 of the input-side engaging portion 14 is brought into contact with one of the two convex curved surfaces 40 provided on the input-side engaged portion 38.

[0137] From this state, as the input member 3 rotates further, the radially inner surface 16 of the input-side engaging portion 14 presses one of the convex curved portions 40 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, so that the radially inner surfaces of the two engaging elements 5 approach each other, and the output-side engaged portions 39 of the two engaging elements 5 clamp the output-side engaging portion 20 of the output member 4 from both radial sides.

[0138] In this way, the output member 4 is rotated so that the flat surface portion 22 of the output-side engaging portion 20 is parallel to the connecting surface portion 47 of the output-side engaged portion 39, while the output-side engaging portion 20 and the output-side engaged portion 39 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.

[0139] 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 4, the output-side engaging portion 20 rotates in the direction of rotation of the output member 4 (clockwise in the example of Figure 4) inside the output-side engaged portions 39 of the two engaging elements 5. The flat surface portion 22 of the outer circumferential surface of the output-side engaging portion 20 presses the output-side engaged portions 39 radially outward, causing the two engaging elements 5 to move toward the pressed surface 7.

[0140] 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 37 of the two engaging elements 5 come into contact with the pressed surface 7 and frictionally engage with the pressed surface 7.

[0141] 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.

[0142] 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 20 and the pressed member 2 so that the pressing surface 37 of the engaging element 5 does not slide (rotate relative to) the pressed surface 7, thereby locking the output member 4.

[0143] 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 part 20 and the pressed member 2 so that the pressing surface 37 of the engaging element 5 slides against the pressed surface 7, thereby semi-locking the output member 4.

[0144] 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 37 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 convex portion 43 of the input-side engaged portion 38.

[0145] 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 37 contacts the pressed surface 7, the surface pressure acting on the contact area between the pressing surface 37 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.

[0146] [Example 2] A second example of the embodiment of this disclosure will be described with reference to Figures 9 to 12. In this example, the configuration of the portion of the output-side engaging portion 20a of the output member 4a that engages axially with the restricting portion 49a of the leaf spring 6a, and the configuration of the leaf spring 6a, differ from those of the first example.

[0147] In this example, the portion of the output-side engaging portion 20a that engages axially with the restricting portion 49a of the leaf spring 6a is provided in the axial intermediate portion of each of the two partial cylindrical surface portions 23a on the outer circumferential surface of the output-side engaging portion 20a, and is composed of engaging protrusions 57 that protrude more than the adjacent portions on both sides in the axial direction.

[0148] The engaging projection 57 has a substantially rectangular cross-sectional shape, and its two outer surfaces in the axial direction are parallel to each other.

[0149] The restricting portion 49a of the leaf spring 6a is composed of a pair of restricting pieces 58. The restricting portion 49a is configured to restrict the relative axial displacement between the output member 4a and the leaf spring 6a by axially clamping the engaging projection 57 with the pair of restricting pieces 58. Specifically, the relative axial displacement between the output member 4a and the leaf spring 6a is restricted by bringing the axial end face of one of the axial restricting pieces 58 to contact or face the axial end face of the other of the axial restricting pieces 58 to contact or face the axial end face of the engaging projection 57.

[0150] In this example, a pair of restricting pieces 58 are configured to connect their radially outer ends to the widthwise outer ends of a pair of axial plate pieces 52. Furthermore, the pair of restricting pieces 58 have end faces that are curved in a roughly S-shape when viewed from the axial direction. That is, in this example, the restricting portion 49a is positioned radially inward from the spring body.

[0151] More specifically, each restricting piece 58 has an outer curved portion 59 that is partially cylindrical and whose radially outer end is connected to the axially outer end of the widthwise outer end of the axial plate piece 52, an outer connecting plate portion 60 that extends inward in the widthwise direction from the radially inner end of the outer curved portion 59, and an inner curved portion 61 that is partially cylindrical and whose radially outer end is connected to the widthwise inner end of the outer connecting plate portion 60.

[0152] In this example, with the leaf spring 6a positioned between the output-side engaging portion 20a and the engaging element 5, the inner curved portions 61 of a pair of restricting pieces 58 are positioned on both axial sides of the engaging projection 57. In this state, the axial end face of the inner curved portion 61 of one axial restricting piece 58 is in light contact with or in close proximity to the axial side of the engaging projection 57, and the axial end face of the inner curved portion 61 of the other axial restricting piece 58 is in light contact with or in close proximity to the axial side of the engaging projection 57. This restricts the relative axial displacement between the output member 4a and the leaf spring 6a.

[0153] In this example, with the leaf spring 6a positioned between the output-side engaging portion 20a and the engaging element 5, the inner surface in the width direction of the inner curved portion 61 of the pair of restricting pieces 58 is in light contact or close proximity to the portions of the partial cylindrical surface 23 of the output-side engaging portion 20a located on both axial sides of the engaging projection 57. This ensures that the leaf spring 6a is positioned in the width direction relative to the output-side engaging portion 20a.

[0154] In this example, the pair of clamping pieces 56a constituting the clamping portion 50a are configured to connect their radially inward ends to the radially inward ends of the inner curved portions 61 of the pair of restricting pieces 58. Furthermore, the pair of clamping pieces 56a have end faces that are curved in a roughly J-shape when viewed from the axial direction.

[0155] More specifically, each clamping piece 56a has an inner connecting plate portion 62 extending outward in the width direction from the radially inner end of the inner curved portion 61, and a curved portion 63 that is partially cylindrical and whose radially inner end is connected to the widthwise outer end of the inner connecting plate portion 62. In this example as well, the clamping portion 50a is positioned radially outward from the spring body 48 so that it can face the axial side of the engaging element 5 regardless of the radial (first direction) movement of the engaging element 5.

[0156] In this example, with the leaf spring 6a positioned between the output-side engaging portion 20a and the engaging element 5, the curved portions 63 of a pair of clamping pieces 56a are positioned on both sides of the engaging element 5 in the axial direction. In this state, the end face on the other axial side of the curved portion 63 of the clamping piece 56a on one side in the axial direction is in light contact or close proximity to the side surface of the engaging element 5 on one side in the axial direction, and the end face on the other axial side of the curved portion 63 of the clamping piece 56a on the other side in the axial direction is in light contact or close proximity to the side surface of the engaging element 5 on the other side in the axial direction. This restricts the relative axial displacement between the engaging element 5 and the leaf spring 6a.

[0157] In the reverse input blocking clutch 1a of this example, the leaf spring 6a can position the engaging element 5 in the axial direction relative to the output member 4a, thus eliminating the need for dedicated parts, namely spacers and stopper members, to restrict the axial movement of the engaging element 5a relative to the output member 4a. In this example as well, the leaf spring 6a can be easily manufactured from sheet metal by punching and bending. The configuration and effects of the other parts of the second example are the same as in the first example. [Explanation of Symbols]

[0158] 1, 1a Reverse input cutoff clutch 2 Pressed member 3 Input Members 4, 4a Output member 5 Engagement element 6, 6a Leaf spring 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 Radial outer surface 18 Ridge 19 Input flange section 20, 20a Output side engagement portion 22 Flat surface part 23, 23a Partial cylindrical surface part 24 Engagement recess 27 Ridge 28 Output shaft section 29 Output flange section 30 Small diameter shaft section 31 Radial rolling bearings 32 Outer ring 33a, 33b Retaining rings 34 Inner Ring 35 Rolling element 36 Plain bearings 37 Pressing surface 38 Input side engaged portion 39 Output side engaged part 40 Convex curved part 41 Convex curved part 42 Radial inner surface 43 Convex portion 44 Radial outer surface 45 Circumferential side view 46 Connection surface 47 Connection surface 48 Spring body 49, 49a Regulatory Department 50, 50a clamping part 51 Width plate piece 52 Axial plate piece 53 Outer plate part 54 Connecting plate section 55 Inner plate part 56, 56a clamping piece 57 Engagement protrusion 58 Regulatory piece 59 Outer curved part 60 Outer connection plate 61 Inner curved section 62 Inner connecting plate section 63 Curved section

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 arranged radially inward from the surface to be pressed, and arranged coaxially with the surface to be pressed, An output member having an output-side engaging portion that is positioned radially inward from the input-side engaging portion and is 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, A leaf spring is disposed between the output-side engaging portion and the engaging element, and elastically biases the engaging element in a direction that brings the pressing surface closer to the pressed surface. 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 leaf spring comprises a spring body that elastically stretches between the engaging element and the output-side engaging portion, a restricting portion that engages axially with the output-side engaging portion to restrict the relative axial displacement between the output member and the leaf spring, and a pair of clamping pieces that clamp the engaging element in the axial direction, thereby restricting the relative axial displacement between the engaging element and the leaf spring. Reverse input blocking clutch.

2. The reverse input shutoff clutch according to claim 1, wherein the output-side engaging portion has an engaging recess on its outer circumferential surface that is recessed compared to adjacent portions on both axial sides and engages with the restricting portion.

3. The reverse input shutoff clutch according to claim 2, wherein the engaging recess is provided on the outer circumferential surface of the output-side engaging portion, in a portion that is circumferentially removed from the portion that engages with the output-side engaged portion.

4. The aforementioned regulatory unit is composed of two regulatory units, The engagement recesses are provided at two locations on the radially opposite sides of the outer circumferential surface of the output-side engagement portion. The reverse input interruption clutch according to claim 3.

5. The spring body is positioned away from the output-side engaged portion on both axial sides and has a pair of widthwise plate pieces elastically pressed against the outer circumferential surface of the output-side engaged portion on both axial sides from the portion that engages with the output-side engaged portion, and a pair of axial plate pieces that connect the widthwise ends of the pair of widthwise plate pieces and are elastically pressed against the radially inner surface of the engaging element. The two restricting portions are connected at their radially outer ends to the widthwise inner ends of the pair of axial plate pieces. The reverse input blocking clutch according to claim 4.

6. The clamping portion is composed of two clamping portions, The reverse input shutoff clutch according to claim 5, wherein the pair of clamping pieces of each of the two clamping portions are connected at their radially inner ends to the widthwise outer ends of the pair of axial plate pieces.

7. The output-side engaging portion has engaging protrusions on its outer circumferential surface that protrude more than the adjacent portions on both sides in the axial direction. The restricting portion has a pair of restricting pieces that clamp the engaging projection in the axial direction. The reverse input interruption clutch according to claim 1.

8. The reverse input shutoff clutch according to claim 7, wherein the engaging projection is provided on the outer circumferential surface of the output-side engaging portion, on a portion that is circumferentially offset from the portion that engages with the output-side engaged portion.

9. The aforementioned regulatory unit is composed of two regulatory units, The engagement projections are provided at two locations on the radially opposite sides of the outer circumferential surface of the output-side engagement portion. The reverse input blocking clutch according to claim 8.

10. The spring body is positioned away from the output-side engaged portion on both axial sides and has a pair of widthwise plate pieces elastically pressed against the outer circumferential surface of the output-side engaged portion on both axial sides and a pair of axial plate pieces that connect the widthwise ends of the pair of widthwise plate pieces and are elastically pressed against the radially inner surface of the engaging element. Each of the two restricting sections has its radially outer end connected to the widthwise outer end of the pair of axial plate pieces. The reverse input blocking clutch according to claim 9.

11. The clamping portion is composed of two clamping portions, Each of the two clamping portions has its radially inward end connected to the radially inward end of the pair of restricting pieces of each of the two restricting portions. The reverse input interruption clutch according to claim 10.

12. The reverse input shutoff clutch according to any one of claims 1 to 11, wherein the engaging element has a convex curved surface portion on at least one of the portions of the input-side engaged portion that engages with the input-side engaging portion and the portion of the output-side engaged portion that engages with the output-side engaging portion.

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