Reverse input cut-off clutch

Abstract

To provide a free type reverse input cutoff clutch capable of shortening the axial size, suppressing the number of components, and stably idling an output member when rotation toque is reversely input to the output member, while actualizing a construction to easily achieve a much smaller size.SOLUTION: A reverse input cutoff clutch 1 includes an output member 3 having a pressed face 23 on the inner peripheral face, an input member 4 having a cam part 30 arranged on the radial inside of the pressed face 23, and arranged coaxially with the pressed face 23, an engagement element 5 having a pair of pressing faces 41 each opposed to the pressed face 23 and isolated from each other in the circumferential direction, and a force imparting member 6 for imparting force to the engagement element 5 to separate each of the pair of pressing faces 41 from the pressed face 23.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a reverse input blocking clutch that has a function of transmitting the rotational torque input to the input member to the output member while blocking the rotational torque reversely input to the output member.

Background Art

[0002] The reverse input blocking clutch includes an input member connected to an input side mechanism such as a drive source and an output member connected to an output side mechanism such as a speed reduction mechanism. The rotational torque input to the input member is transmitted to the output member, while the rotational torque reversely input to the output member is blocked and not transmitted to the input member or only a part of it is transmitted.

[0003] The reverse input blocking clutch is roughly classified into a lock type and a free type according to the difference in the mechanism for blocking the rotational torque reversely input to the output member. The lock type reverse input blocking clutch has a mechanism for preventing (restraining) the rotation of the output member when a rotational torque is reversely input to the output member. On the other hand, the free type reverse input blocking clutch has a mechanism for idling the output member when a rotational torque is 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 according to the use of the device incorporating the reverse input blocking clutch and the like.

[0004] Japanese Patent Application Laid-Open No. 2004-84918 and the like describe a lock type reverse input blocking clutch. In the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2004-84918, when a rotational torque is reversely input to the output member, rolling elements arranged in a wedge-shaped space between an inner member and an outer member are moved to a narrow-width portion in the radial direction of the wedge-shaped space, and the inner member and the outer member are tightened between them, thereby having a mechanism for preventing the rotation of the output member. However, in the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2004-84918, there is a possibility that the rolling elements cannot move from the narrow-width portion to the wide-width portion of the wedge-shaped space, resulting in a problem that the output member is locked.

[0005] On the other hand, Japanese Patent Application Laid-Open No. 2020-8124 describes a free-type reverse input blocking clutch. When rotational torque is input to the input member in the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124, the engaging element moves radially so as to approach the pressed surface based on the engagement with the input engagement cam, and the pressing surface, which is a convex surface in the shape of a cylindrical surface, is brought into contact with the pressed surface, which is a concave surface in the shape of a cylindrical surface, thereby transmitting the rotational torque input to the input member to the output member. On the other hand, when rotational torque is reversely input to the output member, the output member is idled based on the gap formed between the pressed surface and the pressing surface by the force applied by the force applying member, so that the rotational torque reversely input to the output member is not transmitted to the input member.

[0006] In the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124, the radial movement of the engaging element is controlled by the rotation of the input member and the force applied by the force applying member, and it is possible to switch between a locked state in which rotational torque can be transmitted from the input member to the output member and a free state in which the rotational torque reversely input to the output member is blocked. Therefore, according to the structure described in Japanese Patent Application Laid-Open No. 2020-8124, the axial dimension of the entire reverse input blocking clutch device can be shortened.

[0007] Further, in the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124, the engaging element has both a function of transmitting the rotational torque input to the input member to the output member and a function of blocking the rotational torque reversely input to the output member. Therefore, according to the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124, the number of parts can be reduced, and the operation can be stabilized as compared with the case where each of the two functions is provided in a separate member.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124 has room for improvement in terms of further miniaturization.

[0010] In view of the above circumstances, an object of the present invention is to realize a structure that can shorten the axial dimension, reduce the number of parts, and can stably idle the output member when rotational torque is reversely input to the output member, and is easy to further miniaturize in a free-type reverse input blocking clutch.

MEANS FOR SOLVING THE PROBLEMS

[0011] A reverse input blocking clutch according to one aspect of the present invention includes an output member, an input member, at least one an engaging element, and a force applying member.

[0012] The output member has a pressed surface on its inner peripheral surface.

[0013] The input member has a cam portion disposed radially inside the pressed surface and is coaxially disposed with the pressed surface.

[0014] The at least one engaging element each of which has a pair of pressing surfaces that face the pressed surface and are circumferentially spaced apart from each other.

[0015] The force applying member applies a force in a direction in which the pair of pressing surfaces move away from the pressed surface to the engaging element.

[0016] In the reverse input blocking clutch according to one aspect of the present invention, when the force in the direction of bringing the pair of pressing surfaces acting on the engaging member closer to the pressed surface along with the input of rotational torque to the input member is greater than the force applied by the force applying member to the engaging member, the engaging member moves radially in the direction of bringing the pair of pressing surfaces closer to the pressed surface, and the pair of pressing surfaces are frictionally engaged with the pressed surface to transmit the rotational torque input to the input member to the output member. On the other hand, when no rotational torque is input to the input member, or when the force in the direction of bringing the pair of pressing surfaces acting on the engaging member closer to the pressed surface along with the input of rotational torque to the input member is less than or equal to the force applied by the force applying member to the engaging member, a gap is formed between the pressed surface and the pair of pressing surfaces based on the force applied by the force applying member to the engaging member, so that torque is not transmitted between the input member and the output member.

[0017] Note that the force in the direction of bringing the pair of pressing surfaces acting on the engaging member closer to the pressed surface along with the input of rotational torque to the input member is the resultant force of the force that the engaging member tends to move radially in the direction of bringing the pair of pressing surfaces closer to the pressed surface based on the engagement with the cam portion and the centrifugal force acting on the engaging member.

[0018] In the reverse input blocking clutch according to one aspect of the present invention, the input member has an input member side guide portion and and the engaging member has an engaging member side guide portion before In a state where the gap is formed between the pressed surface and the pair of pressing surfaces based on the force applied by the force applying member to the engaging member, the input member side guide portion and the engaging member side guide portion engage without rattling with respect to a first direction that is the direction of proximity and distance of the pair of pressing surfaces with respect to the pressed surface and a second direction orthogonal to the central axis of the input member. free

[0019] Furthermore The outer peripheral surface of the cam portion is composed of a pair of first flat surface portions arranged on both sides in the minor axis direction, a pair of second flat surface portions arranged on both sides in the major axis direction, and a connecting surface portion connecting the major axis direction end portion of the first flat surface portion and the minor axis direction end portion of the second flat surface portion. In the reverse input blocking clutch according to one aspect of the present invention, The engaging element has an engaging concave portion provided on the radially inner surface. ​The inner surface of the engaging concave portion is composed of a bottom surface and a pair of side surface portions. The input member side guide portion is constituted by the minor axis direction end portion of the cam portion, and the engaging element side guide portion is constituted by the engaging concave portion. In the free state, the bottom surface is in surface contact with the first flat surface portion, and the pair of side surface portions are in surface contact with the connecting surface portion.

[0020] The reverse input blocking clutch according to one aspect of the present invention can include a pair of engagement members that sandwich the cam portion from the radially outer side. In this case, the force applying member can be provided so as to span between the pair of engagement members.

[0021] In the reverse input blocking clutch according to one aspect of the present invention, the force applying member can be constituted by an elastic member such as a spring or rubber.

Advantages of the Invention

[0022] According to the reverse input blocking clutch according to one aspect of the present invention, the axial dimension can be shortened, the number of components can be reduced, and when rotational torque is reversely input to the output member, the output member can be stably idled, and further miniaturization can be easily achieved.

Brief Description of the Drawings

[0023]

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DETAILED DESCRIPTION OF THE INVENTION

[0024] [First Example of the Embodiment] The first example of the embodiment of the present invention will be described with reference to FIGS. 1 to 8.

[0025] <Structure of the Reverse Input Blocking Clutch 1>[ The reverse input blocking clutch 1 in this example is a free (idling) type reverse input blocking clutch, and includes a housing 2, an output member 3, an input member 4, a pair of engaging members 5, and a pair of force applying members 6. In the following description, unless otherwise specified, the axial direction, the radial direction, and the circumferential direction refer to the axial direction, the radial direction, and the circumferential direction of the output member 3, which are the same as those of the input member 4. Also, one side in the axial direction refers to the output member 3 side (the right side in FIG. 1), and the other side in the axial direction refers to the input member 4 side (the left side in FIG. 1).

[0026] The housing 2 is configured in a stepped cylindrical shape. In this example, the housing 2 has a hollow circular plate-shaped side plate portion 7, a large-diameter cylindrical portion 8 that projects over the entire circumference from the radially outer portion of the side plate portion 7 toward one side in the axial direction, and a small-diameter cylindrical portion 9 that is bent over the entire circumference from the radially inner end portion of the side plate portion 7 toward the other side in the axial direction. Further, the housing 2 has an inward flange portion 10 that is bent over the entire circumference from the end portion on the other side in the axial direction of the small-diameter cylindrical portion 9 toward the radially inner side, and has through holes 11 that penetrate in the axial direction at a plurality of circumferential positions of the portion of the side plate portion 7 that projects radially outward from the outer peripheral surface of the large-diameter cylindrical portion 8.

[0027] The housing 2 is supported and fixed to the fixing member 13 by screwing and further tightening a bolt 12 inserted through the through hole 11 into a threaded hole 14 that opens to one axial side surface of the fixing member 13 that does not rotate during use.

[0028] The output member 3 is connected to an output-side mechanism such as a speed reduction mechanism and outputs a rotational torque. The output member 3 has an output shaft portion 15, a cylindrical portion 16, and a side plate portion 17.

[0029] The output shaft portion 15 has a columnar small-diameter portion 18 disposed on one axial side and a cylindrical large-diameter portion 19 disposed on the other axial side. The output shaft portion 15 connects the tip end portion (one axial end portion) of the small-diameter portion 18 to the input portion of the output-side mechanism so as to be torque-transmittable, or is integrally formed with the input portion of the output-side mechanism. The large-diameter portion 19 has an inner peripheral surface in a stepped cylindrical shape formed by connecting a small-diameter cylindrical surface portion 20 on one axial side and a large-diameter cylindrical surface portion 21 on the other axial side by a stepped portion 22 facing the other axial side.

[0030] The cylindrical portion 16 has a pressed surface 23 that is a concave surface in a cylindrical shape on the entire inner peripheral surface, and is disposed on the other axial side of the output shaft portion 15.

[0031] The side plate portion 17 is configured in a hollow circular plate shape and connects the end portion on the other axial side of the output shaft portion 15 (large-diameter portion 19) and the portion on one axial side of the cylindrical portion 16.

[0032] In the reverse input blocking clutch 1 of this example, the cylindrical portion 16 of the output member 3 is rotatably supported inside the radial direction of the large-diameter cylindrical portion 8 of the housing 2 via a radial needle bearing 24. That is, an outer ring 25 formed by bending a metal plate into a substantially U-shaped cross section is press-fitted into the large-diameter cylindrical portion 8, and a plurality of needles 27 held by a cage 26 are rotatably arranged between the inner peripheral surface of the outer ring 25 and the outer peripheral surface of the cylindrical portion 16, thereby constituting the radial needle bearing 24. Thereby, the output member 3 is rotatably supported with respect to the housing 2.

[0033] In this example, an opening on one axial side of a cylindrical space that exists between the inner peripheral surface of the large-diameter cylindrical portion 8 and the outer peripheral surface of the cylindrical portion 16 and in which the radial needle bearing 24 is installed is closed by the seal member 28. This prevents the grease enclosed in the cylindrical space from leaking into the external space and also prevents foreign matters such as moisture from entering the cylindrical space.

[0034] The input member 4 has, in order from the other axial side, a large-diameter shaft portion 29, a cam portion 30, and a small-diameter shaft portion 31. The large-diameter shaft portion 29, the cam portion 30, and the small-diameter shaft portion 31 are all coaxially and serially arranged.

[0035] The large-diameter shaft portion 29 has a columnar shape, and its base end portion (the end portion on the other axial side) is connected to the output portion of the input-side mechanism so as to be torque-transmittable, or is integrally formed with the output portion of the input-side mechanism. The large-diameter shaft portion 29 has an outward flange portion 32 that protrudes radially outward at one axial end portion.

[0036] The cam portion 30 has a substantially rectangular end surface shape including four corners that are circular arc-shaped or elliptical arc-shaped when viewed in the axial direction. That is, the outer peripheral surface of the cam portion 30 is composed of a pair of first flat surface portions 33 arranged on both sides in the short-axis direction (the vertical direction in FIG. 4), a pair of second flat surface portions 34 arranged on both sides in the long-axis direction (the left-right direction in FIG. 4), and a connecting surface portion 35 having a circular arc or elliptical arc cross section that connects the long-axis direction end portion of the first flat surface portion 33 and the short-axis direction end portion of the second flat surface portion 34. Therefore, the distance from the central axis (the rotation center of the cam portion 30) O of the input member 4 to the outer peripheral surface of the cam portion 30 changes in the circumferential direction. Also, the width dimension of the cam portion 30 in the long-axis direction becomes smaller toward the end portions in the short-axis direction. Note that the first flat surface portion 33 and the connecting surface portion 35 are smoothly connected to each other at their end portions in the tangential direction.

[0037] The small-diameter shaft portion 31 is configured in a columnar shape.

[0038] The input member 4 rotatably supports the large-diameter shaft portion 29 inside the radial direction of the small-diameter cylindrical portion 9 of the housing 2 via a radial rolling bearing 36a, and rotatably supports the small-diameter shaft portion 31 inside the radial direction of the large-diameter portion 19 of the output member 3 via a radial rolling bearing 36b. In this state, the cam portion 30 is disposed inside the radial direction of the pressed surface 23.

[0039] That is, the radial rolling bearing 36a on the other axial side includes an outer ring 37a fitted inside the small-diameter cylindrical portion 9, an inner ring 38a fitted outside the large-diameter shaft portion 29, and a plurality of rolling elements 39a disposed between the inner peripheral surface of the outer ring 37a and the outer peripheral surface of the inner ring 38a so as to be freely rollable. The outer ring 37a is clamped from both axial sides between one axial side surface of the inward flange portion 10 and a retaining ring 40a locked to the inner peripheral surface of one axial end portion of the small-diameter cylindrical portion 9. The inner ring 38a is clamped from both axial sides between the other axial side surface of the outward flange portion 32 and a retaining ring 40b locked to the outer peripheral surface of the intermediate axial portion of the large-diameter shaft portion 29.

[0040] Also, the radial rolling bearing 36b on one axial side includes an outer ring 37b fitted inside a large-diameter cylindrical surface portion 21 provided on the inner peripheral surface of the large-diameter portion 19, an inner ring 38b fitted outside the small-diameter shaft portion 31, and a plurality of rolling elements 39b disposed between the inner peripheral surface of the outer ring 37b and the outer peripheral surface of the inner ring 38b so as to be freely rollable. The outer ring 37b is clamped from both axial sides between the stepped portion 22 and a retaining ring 40c locked to the other axial end portion of the large-diameter cylindrical surface portion 21. The inner ring 38b is clamped from both axial sides between one axial end surface of the cam portion 30 and a retaining ring 40d locked to the outer peripheral surface of one axial end portion of the small-diameter shaft portion 31.

[0041] In this example, the radial rolling bearings 36a and 36b are constituted by radial ball bearings using balls as the rolling elements 39a and 39b. However, the radial rolling bearings 36a and 36b can also be constituted by radial cylindrical roller bearings using cylindrical rollers (including needles) as the rolling elements.

[0042] The pair of engaging members 5 has an end face shape that is substantially semi-circular (substantially arcuate) when viewed axially. The pair of engaging members 5 is disposed between the pressed surface 23 of the output member 3 and the cam portion 30 of the input member 4 so as to sandwich the cam portion 30 from both sides in the minor axis direction of the cam portion 30. The pair of engaging members 5 are identical parts that are shaped and sized the same as each other.

[0043] The pair of engaging members 5 are arranged such that their radially outer surfaces corresponding to the arc face each other on opposite sides, and their radially inner surfaces corresponding to the chord face each other, and the radially outer surfaces are movable in a first direction (the direction indicated by α in FIG. 4), which is a direction of moving closer to and farther from the pressed surface 23. That is, with the pair of engaging members 5 disposed between the pressed surface 23 and the cam portion 30, the inner diameter of the pressed surface 23 and the radial dimensions of the engaging members 5 are regulated so that each engaging member 5 can move its radially outer surface in the first direction with respect to the pressed surface 23.

[0044] The pair of engaging members 5 each have a pair of pressing surfaces 41 on their radially outer surfaces that face the pressed surface 23 and are circumferentially spaced apart from each other. Each pressing surface 41 is constituted by a partial cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface 23. Note that, of the radially outer surfaces of the pair of engaging members 5, the portions that are circumferentially offset from the pair of pressing surfaces 41 are located radially inward of a virtual circle centered on the central axis O of the input member 4 and tangent to the pair of pressing surfaces 41 when viewed axially. That is, in a state where the pair of pressing surfaces 41 are in contact with the pressed surface 23, the portions of the radially outer surfaces of the pair of engaging members 5 that are circumferentially offset from the pair of pressing surfaces 41 do not contact the pressed surface 23.

[0045] Each pressing surface 41 preferably has a surface property with a larger coefficient of friction with respect to the pressed surface 23 than the other portions of the engaging member 5. Also, each pressing surface 41 can be integrally formed with the other portions of the engaging member 5, or can be formed on the surface of a friction material fixed to the other portions of the engaging member 5 by adhesion, bonding, or the like.

[0046] Further, a pair of engaging members 5 has a substantially trapezoidal engaging recess 42 at the central portion of the radially inner surface in the second direction (the direction indicated by β in FIG. 4) orthogonal to the first direction and the central axis O of the output member 3.

[0047] In the free state of the reverse input blocking clutch 1 described later, the engaging recess 42 engages without play in the second direction β with the short-axis direction end portion of the cam portion 30 of the input member 4. That is, in this example, the short-axis direction end portion of the cam portion 30 constitutes the input member side guide portion, and the engaging recess 42 constitutes the engaging member side guide portion. The inner surface of the engaging recess 42 is composed of a bottom surface 43 and a pair of side surfaces 44.

[0048] The bottom surface 43 is composed of a flat surface orthogonal to the first direction. The length dimension (the length dimension in the second direction) of the bottom surface 43 is the same as or slightly longer than the length dimension of the first flat surface portion 33 of the cam portion 30.

[0049] The pair of side surfaces 44 are arranged on both sides in the second direction of the inner surface of the engaging recess 42 and face each other in the second direction. In this example, the pair of side surfaces 44 are formed by concave curved surfaces that incline in a direction in which the distance between them increases as they go toward the radially inner side of the engaging member 5, that is, in a direction away from the pressed surface 23 in the first direction. Therefore, the width dimension of the engaging recess 42 in the second direction increases toward the opening side. The pair of side surfaces 44 have the same curvature radius as the curvature radius of the connection surface portion 35 of the cam portion 30 or a curvature radius slightly larger than the curvature radius of the connection surface portion 35. It should be noted that the bottom surface 43 and the side surfaces 44 are smoothly connected to each other at their ends in the tangential direction.

[0050] For this reason, in the free state of the reverse input blocking clutch 1, the bottom surface 43 is in surface contact with the first flat surface portion 33, and the pair of side surfaces 44 are in surface contact with the connection surface portion 35.

[0051] Further, a pair of engaging members 5 has semi-elliptical cutout portions 45 on both sides of the radially inner surface that sandwich the engaging recess 42 in the second direction, and locking holes 46 that penetrate axially in portions located radially outside the cutout portions 45.

[0052] A pair of force-applying members 6 applies a force to the pair of engaging members 5 in a direction in which the pair of pressing surfaces 41 move away from the pressed surface 23. In this example, the pair of force-applying members 6 applies an elastic force in a direction in which they approach each other to the pair of engaging members 5. For this purpose, in this example, the pair of force-applying members 6 is configured by tension coil springs. That is, the pair of force-applying members 6 includes a coil portion 77 formed by bending an elastic metal wire into a spiral shape, and a pair of locking arm portions 78 bent substantially L-shaped from both end portions on both sides of the coil portion 77.

[0053] Each force-applying member 6 is passed between the pair of engaging members 5 by locking (inserting) the locking arm portion 78 into the locking hole 46, and applies an elastic force in a direction in which the pair of engaging members 5 approach each other. As a result, the cam portion 30 of the input member 4 is elastically clamped from both sides in the radial direction by the engaging recesses 42 of the pair of engaging members 5. Specifically, the bottom surface 43 is elastically pressed against the first flat surface portion 33, and the side surface portion 44 is elastically pressed against the connecting surface portion 35. Then, in the free state of the reverse input blocking clutch 1, the posture (rotation phase) of the cam portion 30 is regulated so that the major axis direction of the cam portion 30 is substantially parallel to the radially inner surface of the engaging member 5, and a gap 79 is formed between the pressed surface 23 and the pair of pressing surfaces 41.

[0054] Note that, in a state where the pair of force-applying members 6 is passed between the pair of engaging members 5, both end portions in the length direction of the coil portion 77 and the pair of locking arm portions 78 are disposed inside the cutout portions 45.

[0055] <Explanation of the operation of the reverse input blocking clutch 1> Next, the operation of the reverse input blocking clutch 1 of this example will be described.

[0056] First, a case will be described where the force F in the direction of bringing the pair of pressing surfaces 41 acting on the pair of engaging members 5 closer to the pressed surface 23 as the input member 4 rotates is greater than the force f applied by the pair of force applying members 6 to the pair of engaging members 5 (F > f).

[0057] When a rotational torque is input to the input member 4, as shown in FIG. 5, the cam portion 30 attempts to rotate in the rotational direction of the input member 4 (clockwise in the example of FIG. 5) inside the pair of engaging recesses 42. Then, the connecting surface portion 35 of the cam portion 30 presses the bottom surface 43 of the engaging recess 42. At this time, based on the connecting surface portion 35 pressing the bottom surface 43, the resultant force F of the force that causes the pair of engaging members 5 to move radially outward in the direction of bringing the pair of pressing surfaces 41 closer to the pressed surface 23 and the centrifugal force acting on the pair of engaging members 5 as the pair of engaging members 5 rotate about the central axis O of the input member 4 is greater than the force f applied by the pair of force applying members 6 to the pair of engaging members 5, the pair of engaging members 5 move radially outward in the direction of bringing the pair of pressing surfaces 41 closer to the pressed surface 23. Then, the pair of pressing surfaces 41 are pressed against the pressed surface 23 for frictional engagement, and the pair of engaging members 5 are stretched between the cam portion 30 and the pressed surface 23. As a result, the reverse input blocking clutch 1 is switched to a locked state in which rotational torque can be transmitted from the input member 4 to the output member 3. As a result, the rotational torque input to the input member 4 is transmitted to the output member 3 via the pair of engaging members 5 and output from the output member 3.

[0058] In the reverse input blocking clutch 1 of this example, when the resultant force F is greater than the force f applied by the pair of force applying members 6 to the pair of engaging members 5, regardless of the rotational direction of the input member 4, the pair of engaging members 5 are each moved in the direction of approaching the pressed surface 23 with respect to the first direction. Then, the rotational torque input to the input member 4 is transmitted to the output member 3 via the pair of engaging members 5.

[0059] Next, a case will be described where the force F in the direction of bringing the pair of pressing surfaces 41 acting on the pair of engaging members 5 closer to the pressed surface 23 as the input member 4 rotates is less than or equal to the force f applied by the pair of force applying members 6 to the pair of engaging members 5 (F ≤ f).

[0060] Including the case where no rotational torque is input to the input member 4, as the input member 4 rotates, the resultant force F of the force that causes the pair of engaging members 5 to move radially outward in a direction approaching the pair of pressing surfaces 41 toward the pressed surface 23 and the centrifugal force acting on the pair of engaging members 5 is equal to or less than the force f applied by the pair of force applying members 6 to the engaging members 5. When this occurs, a gap 79 is formed between the pressed surface 23 and the pair of pressing surfaces 41 based on the force f applied by the pair of force applying members 6 to the engaging members 5. As a result, the reverse input blocking clutch 1 switches to a free state in which rotational torque is not transmitted between the input member 4 and the output member 3. Consequently, the output member 3 idles relative to the input member 4 and / or the input member 4 idles relative to the output member 3.

[0061] In the reverse input blocking clutch 1 of this example, when the resultant force F is equal to or less than the force f applied by the pair of force applying members 6 to the pair of engaging members 5, rotational torque is not transmitted between the input member 4 and the output member 3 regardless of the rotational direction of the input member 4 or the output member 3.

[0062] Note that the magnitude of the force (elastic force) applied by the pair of force applying members 6 to the pair of engaging members 5 is appropriately set according to the minimum values of the torque and rotational speed to be transmitted from the input member 4 to the output member 3.

[0063] According to the reverse input blocking clutch 1 of this example having the above configuration and operating as described above, for the same reasons as the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124, the axial dimension can be shortened, the number of parts can be reduced, and when rotational torque is reverse input to the output member 3, the output member 3 can be stably idled.

[0064] That is, the reverse input blocking clutch 1 of this example controls the radial movement (axial movement) of the engaging element 5 by utilizing the rotation of the input member 4 and the force exerted by the force applying member 6. Specifically, by using the elastic force of a pair of force applying members 6 each constituted by a tension coil spring to pull a pair of engaging elements 5 inward in the radial direction, a gap 79 is formed between the pressed surface 23 and the pair of pressing surfaces 41 in a state where no rotational torque is input to the input member 4. Then, when the force F in the direction of bringing the pair of pressing surfaces 41 acting on the pair of engaging elements 5 closer to the pressed surface 23 with the rotation of the input member 4 becomes greater than the force f applied by the pair of force applying members 6 to the pair of engaging elements 5, the cam portion 30 is relatively rotated with respect to the engaging element 5 to move the pair of engaging elements 5 outward in the radial direction and bring the pair of pressing surfaces 41 into contact with the pressed surface 23.

[0065] On the other hand, when the force F in the direction of bringing the pair of pressing surfaces 41 acting on the pair of engaging elements 5 closer to the pressed surface 23 with the rotation of the input member 4 is equal to or less than the force f applied by the pair of force applying members 6 to the pair of engaging elements 5, the input member 4 and / or the output member 3 is idled based on the gap 79 between the pressed surface 23 and the pair of pressing surfaces 41 formed by the elastic force of the pair of force applying members 6. In this way, the reverse input blocking clutch 1 of this example can switch between a locked state in which rotational torque can be transmitted from the input member 4 to the output member 3 and a free state in which the transmission of rotational torque between the input member 4 and the output member 3 is blocked, based on the radial movement of the pair of engaging elements 5 controlled by the rotation of the input member 4 and the elastic force of the pair of force applying members 6. Therefore, the axial dimension of the entire device of the reverse input blocking clutch 1 can be shortened.

[0066] Further, the pair of engaging members 5 are provided with both a function of transmitting the rotational torque input to the input member 4 to the output member 3 and a function of moving radially away from the pressed surface 23 to interrupt the transmission of the rotational torque between the input member 4 and the output member 3. For this reason, the number of parts of the reverse input blocking clutch 1 can be reduced, and the operation can be stabilized as compared with the case where the two functions are provided to different members. For example, when the function of transmitting the rotational torque and the function of interrupting the rotational torque are provided to different members, there is a possibility that the timing of releasing the interruption of the rotational torque reverse-input to the output member and the timing of starting the transmission of the rotational torque from the input member to the output member may deviate. In this case, if a rotational torque is reverse-input to the output member between the release of the interruption of the rotational torque and the start of the transmission of the rotational torque to the output member, the rotational torque may be interrupted again. In this example, since the engaging member 5 is provided with both a function of transmitting the rotational torque input to the input member 4 to the output member 3 and a function of interrupting the rotational torque reverse-input to the output member 3, such inconvenience can be prevented.

[0067] Further, since the direction of the force acting on the pair of engaging members 5 from the input member 4 and the direction of the force applied to the pair of engaging members 5 from the pair of force applying members 6 are opposite to each other, the moving direction of the pair of engaging members 5 can be controlled by regulating the magnitude relationship between the two forces. For this reason, the switching operation between the locked state in which the transmission of the rotational torque from the input member 4 to the output member 3 is possible and the free state in which the transmission of the rotational torque between the input member 4 and the output member 3 is impossible can be performed stably and reliably.

[0068] Furthermore, in this example, when the force F in the direction of bringing the pair of pressing surfaces 41 acting on the pair of engaging members 5 closer to the pressed surface 23 as the input member 4 rotates becomes greater than the force f applied by the pair of force applying members 6 to the pair of engaging members 5, the pair of pressing surfaces 41 formed on the radially outer surface of the engaging member 5 are pressed against the pressed surface 23, which is a cylindrical concave surface formed on the inner peripheral surface of the output member 3, and rotational torque is transmitted from the input member 4 to the output member 3. On the other hand, when the force F in the direction of bringing the pair of pressing surfaces 41 acting on the pair of engaging members 5 closer to the pressed surface 23 as the input member 4 rotates becomes less than or equal to the force f applied by the pair of force applying members 6 to the pair of engaging members 5, the pair of pressing surfaces 41 are separated from the pressed surface 23 by the elastic force of the pair of force applying members 6. Therefore, according to the reverse input blocking clutch 1 of this example, unlike the conventional structure described in Japanese Patent Application Laid-Open No. 2004-84918, it is possible to effectively prevent the rolling elements from being unable to move from the narrow portion to the wide portion of the wedge-shaped space and the output member from remaining locked. Therefore, when the force F in the direction of bringing the pair of pressing surfaces 41 acting on the pair of engaging members 5 closer to the pressed surface 23 as the input member 4 rotates becomes less than or equal to the force f applied by the pair of force applying members 6 to the pair of engaging members 5 and reverse input of rotational torque occurs in the output member 3, the output member 3 can be stably idled. Furthermore, since the pair of force applying members 6 can prevent the pair of pressing surfaces 41 from contacting the pressed surface 23 based only on the centrifugal force acting on the pair of engaging members 5 due to inertial rotation of the input member 4 or the like, it is possible to effectively prevent the rotational torque reverse-input to the output member 3 from being transmitted to the input member 4.

[0069] Furthermore, the engaging member 5 constituting the reverse input blocking clutch 1 can easily increase the surface hardness by heat treatment, coating treatment, or the like. Therefore, wear of the engaging member 5 can be made less likely to occur, and the durability of the entire reverse input blocking clutch 1 can be enhanced.

[0070] Further, the reverse input blocking clutch 1 of this example is easier to be further miniaturized as compared with the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124. That is, in the reverse input blocking clutch 1 of this example, a pair of engaging members 5 have pressing surfaces 41 at two positions circumferentially separated on the radially outer surface. Therefore, according to the reverse input blocking clutch 1 of this example, as compared with the case of frictionally engaging one pressing surface with the surface to be pressed as in the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124, the frictional engagement force between the surface to be pressed 23 and the pair of pressing surfaces 41 can be increased by the wedge effect. Therefore, when the frictional engagement force between the output member 3 and the engaging member 5 is the same, the outer diameter dimension and / or the axial dimension of the reverse input blocking clutch 1 of this example can be made smaller than those of the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124.

[0071] Further, in the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124, the dimension of the bottom surface of the engaging recess (input engaging recess) formed on the radially inner surface of the engaging member in the second direction is made larger than the dimension in the major axis direction of the cam portion (input engaging cam) of the input member. Therefore, in the free state where rotational torque is not transmitted between the input member and the output member, the engaging member may shift in the second direction with respect to the input member. For this reason, it is necessary to ensure a certain degree of large radial dimension of the gap between the surface to be pressed and the pressing surface in the free state.

[0072] On the other hand, in the reverse input blocking clutch 1 of this example, in the free state, the end portion in the minor axis direction of the cam portion 30 of the input member 4 and the engaging recesses 42 of the pair of engaging members 5 are engaged without rattling in the second direction. Therefore, in the free state, it is possible to prevent the pair of engaging members 5 from shifting in the second direction with respect to the input member 4. For this reason, the radial dimension of the gap 79 between the surface to be pressed 23 and the pair of pressing surfaces 41 in the free state can be made smaller. Also from this aspect, the reverse input blocking clutch 1 of this example is easier to be further miniaturized as compared with the reverse input blocking clutch described in Japanese Patent Application Laid-Open No. 2020-8124.

[0073] In the reverse input blocking clutch 1 of this example, the width dimension of the cam portion 30 in the major axis direction is made smaller toward the end portions in the minor axis direction, and the width dimension of the engaging recess 42 in the second direction is made larger toward the opening side. For this reason, as shown in FIGS. 5→FIG. 6 and FIGS. 7(A)→FIG. 7(B), when the reverse input blocking clutch 1 switches from the locked state to the free state, a pair of connection surface portions 35 located on both sides in the major axis direction of the end portion in the minor axis direction of the cam portion 30 guides a pair of side surface portions 44 located on both sides in the second direction of the engaging recess 42, thereby restricting the pair of engaging elements 5 from moving in the second direction. For this reason, even when the end portion in the minor axis direction of the cam portion 30 of the input member 4 and the engaging recesses 42 of the pair of engaging elements 5 are engaged without rattling in the second direction in the free state, the switching from the locked state to the free state can be smoothly performed.

[0074] First Example of Reference Example Regarding the First Example of Reference Example of the present invention, it will be described with reference to FIGS. 9 to 14. This Reference Example In the reverse input blocking clutch 1a of the

[0075] The input member 4a has a pair of engaging convex portions 47 that project radially outward from the central portions in the major axis direction of a pair of first flat surface portions 33 arranged on both sides in the minor axis direction of the cam portion 30a. The pair of engaging convex portions 47 has a quarter-circular arc-shaped contour when viewed from the axial direction. This Reference Example In the

[0076] ​​One pair of engaging members 5a has a quarter-circular arc-shaped engaging recess 42a at the central portion of the radially inner surface in the second direction. The inner surface of the engaging recess 42a is formed by a partial cylindrical concave surface having a curvature radius equal to the curvature radius of the engaging convex portion 47 or slightly larger than the curvature radius of the engaging convex portion 47. Therefore, the engaging recess 42a engages with the engaging convex portion 47 without rattling in the free state of the reverse input blocking clutch 1a. That is, This Reference Example In this case, the engaging convex portion 47 constitutes the input member side guide portion, and the engaging recess 42a constitutes the engaging member side guide portion.

[0077] This Reference Example In the reverse input blocking clutch 1a, when rotational torque is input to the input member 4a, as shown in FIG. 11, the connection surface portion 35 of the cam portion 30a presses the portion of the engaging member 5a that has come out of the engaging recess 42a. That is, This Reference Example In this case, the engaging convex portion 47a that engages with the engaging recess 42a of the engaging member 5a in the free state is located closer to the central axis O of the input member 4a in the second direction than the connection surface portion 35, which is the portion of the cam portion 30a that presses the engaging member 5a when rotational torque is input to the input member 4a.

[0078] This Reference Example According to the reverse input blocking clutch 1a, the manufacturing cost can be easily reduced.

[0079] That is, in the reverse input blocking clutch 1 according to the first example of the embodiment, in the free state, in order to engage the end portion in the minor axis direction of the cam portion 30 and the engaging recess 42 without rattling in the second direction, it is necessary to perform a finishing process such as polishing on the outer surface of the end portion in the minor axis direction of the cam portion 30 and the inner surface of the engaging recess 42. In the reverse input blocking clutch 1 according to the first example of the embodiment, the outer surface of the end portion in the minor axis direction of the cam portion 30 and the inner surface of the engaging recess 42 are configured by a composite surface formed by combining a plurality of surfaces with different radii of curvature. Specifically, since the outer surface of the end portion in the minor axis direction of the cam portion 30 is configured by connecting a pair of connecting surface portions 35 to each other by the first flat surface portion 33, when performing a finishing process on the outer surface of the cam portion 30, it is necessary to perform a finishing process separately on the pair of connecting surface portions 35 and the first flat surface portion 33, respectively. Further, since the inner surface of the engaging recess 42 is configured by connecting a pair of side surface portions 44 by the bottom surface 43, when performing a finishing process on the engaging recess 42, it is necessary to perform a finishing process separately on the pair of side surface portions 44 and the bottom surface 43, respectively.

[0080] In contrast, This Reference Example in the reverse input blocking clutch 1a, the inner surface of the engaging recess 42a and the outer surface of the engaging convex portion 47, which engage with each other in the free state, are both configured by a single partial cylindrical surface. Therefore, when performing a finishing process on the inner surface of the engaging recess 42a, the entire inner surface of the engaging recess 42a can be finished at once. Further, when performing a finishing process on the outer surface of the engaging convex portion 47, the entire outer surface of the engaging convex portion 47 can be finished at once. For this reason, This Reference Example the reverse input blocking clutch 1a is easier to reduce the manufacturing cost compared to the reverse input blocking clutch 1 according to the first example of the embodiment. The configurations and operational effects of the other parts are the same as those of the first example of the embodiment.

[0081] Second Example of Reference Example Regarding the Second Example of Reference Example of the present invention, it will be described with reference to FIGS. 15 to 20. This Reference Example In the reverse input blocking clutch 1b, in the free state, the structure of the engaging portion for preventing the pair of engaging members 5b from shifting in the second direction with respect to the input member 4b is the same as that of the first example of the embodiment and​​First Example of Reference Example is different from.

[0082] The input member 4b includes a shaft main body 48 and a pair of pins 49.

[0083] The shaft main body 48 has, in order from the other side in the axial direction, a large-diameter shaft portion 29 and a cam portion 30b. The cam portion 30b has a semi-circular concave portion 50 in the central portion in the major axis direction of a pair of first flat surface portions 33 arranged on both sides in the minor axis direction.

[0084] The pair of pins 49 has a cylindrical shape and is supported and fixed on both sides in the minor axis direction of the cam portion 30b. Specifically, by fitting and fixing the base end portions (the end portions on the other side in the axial direction) of the pair of pins 49 into press-fitting holes that open on one axial side surface of the large-diameter shaft portion 29, the pair of pins 49 is supported and fixed to the shaft main body 48. Thereby, by protruding half portions of the pair of pins 49 radially outward from the central portion in the major axis direction of a pair of first flat surface portions 33 arranged on both sides in the minor axis direction of the cam portion 30b, a pair of engaging convex portions 47a is provided.

[0085] Each of the pair of engaging members 5b has an engaging concave portion 42b at the central portion in the second direction on the radially inner surface. The inner surface of the engaging concave portion 42b is formed by a composite surface having a concave curved surface portion 51 and a pair of inclined surface portions 52. The concave curved surface portion 51 has a curvature radius that is the same as the curvature radius of the engaging convex portion 47a (pin 49) or slightly larger than the curvature radius of the engaging convex portion 47a. The pair of inclined surface portions 52 is formed by flat surfaces that extend in the tangential direction at the end portions of the concave curved surface portion 51 from the end portions of the concave curved surface portion 51 when viewed from the axial direction.

[0086] This Reference Example In the reverse input blocking clutch 1b, when rotational torque is input to the input member 4b, as shown in FIG. 17, the connection surface portion 35 of the cam portion 30b presses the portion of the engaging member 5b that has come out of the engaging concave portion 42b. That is, This Reference ExampleIn the free state, the engaging convex portion 47a that engages with the engaging concave portion 42b of the engaging member 5b is located closer to the central axis O of the input member 4b in the second direction than the connecting surface portion 35, which is the portion of the cam portion 30b that presses the engaging member 5b when rotational torque is input to the input member 4b.

[0087] This Reference Example In this case, since the engaging convex portion 47a is provided by supporting and fixing a pair of pins 49 each having a columnar shape to the shaft body 48, it is easy to ensure the shape accuracy of the engaging convex portion 47a. That is, while ensuring the shape accuracy of the engaging convex portion 47a, the manufacturing cost can be suppressed. The configurations and operational effects of the other portions are the same as those of the first example of the embodiment and First Example of Reference Example the same.

[0088] [Example of Embodiment 2 Example] The second 2 example of the embodiment of the present invention will be described with reference to FIG. 21. The feature of this example is that the reverse input blocking clutch 1 is applied to the engine drive device 53. Hereinafter, the engine drive device 53 of this example will be specifically described.

[0089] When starting the engine 54, the starter motor 55 rotates the crankshaft 56 to a rotational speed at which the engine 54 can be started. However, once the engine 54 starts operating, it can continue to operate even without the starter motor 55. For this reason, if the starter motor 55 and the engine 54 are connected so as to enable torque transmission in both directions, after the engine 54 starts operating, the starter motor 55 becomes a load on the engine 54.

[0090] Therefore, in the engine drive device 53 of this example, a reverse input blocking clutch 1 is provided between the starter motor 55 and the engine 54. Thereby, torque is transmitted from the starter motor 55 to the crankshaft 56, but torque is not transmitted from the crankshaft 56 to the starter motor 55. The basic configuration of the reverse input blocking clutch 1 is the same as the structure of the first example of the embodiment.

[0091] In particular, in this example, the input member 4 constituting the reverse input blocking clutch 1 is provided integrally with the motor output shaft 57 of the starter motor 55. Further, the output member 3 constituting the reverse input blocking clutch 1 is provided integrally with the pinion shaft 59 having a pinion 58 at its tip. Therefore, a substantially elliptical columnar cam portion 30 (see FIGS. 1 to 6) is provided at the tip of the motor output shaft 57, and a cylindrical portion 16 (see FIGS. 1 to 6) having a pressed surface 23 on its inner peripheral surface is provided at the base end portion of the pinion shaft 59. And between the cam portion 30 and the cylindrical portion 16, a pair of engaging members 5 (see FIGS. 1 to 6) are arranged so as to sandwich the cam portion 30 from both sides in the radial direction. Further, a pair of force applying members 6 (see FIGS. 2 to 6) are provided so as to span the pair of engaging members 5. Further, the pinion 58 meshes with a ring gear 61 formed on the outer peripheral surface of a flywheel 60 fixed to the crankshaft 56.

[0092] In the engine drive device 53 of this example having the above-described configuration, when starting the engine 54, the starter motor 55 is rotationally driven. As a result, the rotation of the motor output shaft 57 of the starter motor 55 is transmitted to the crankshaft 56 via the reverse input blocking clutch 1 and the meshing portion between the pinion 58 and the ring gear 61. Then, the rotational speed of the crankshaft 56 is increased to a rotational speed at which the engine 54 can be started, and the engine 54 is started. Further, after the engine 54 is started in this way, the drive of the starter motor 55 is stopped. When the engine 54 is started, the crankshaft 56 rotates without depending on the starter motor 55. For this reason, rotational torque is reversely input to the reverse input blocking clutch 1 from the pinion shaft 59 (crankshaft 56), but since there is a gap 79 between the pressed surface 23 and the pair of pressing surfaces 41 due to the elasticity of the force applying member 6, the rotation of the pinion shaft 59 is not transmitted to the motor output shaft 57, and the pinion shaft 59 idles. Thus, in this example, it is possible to prevent the rotational torque reversely input from the crankshaft 56 from being transmitted to the starter motor 55. Therefore, after the engine 54 is started, it is possible to prevent the starter motor 55 from becoming a load, and the fuel consumption performance of the engine 54 can be improved. Regarding other configurations and operational effects, they are the same as those of the first example of the embodiment.

[0093] [Embodiment No. 3 Example] The 3 example of the embodiment of the present invention will be described with reference to FIG. 22. The feature of this example is that the reverse input blocking clutch 1 is applied to the steering device 62. Hereinafter, the steering device 62 of this example will be specifically described.

[0094] The steering device 62 is for applying a steering angle corresponding to the operation amount of the steering wheel 64 to a pair of left and right steering wheels 63. In order to ensure the safety of the occupant even if a failure occurs, the steering wheel 64 and the steering wheels 63 are mechanically connected via a rotating shaft 65 such as a steering shaft that rotates based on the operation of the steering wheel 64, a steering gear unit 66, a tie rod 67, and the like.

[0095] By the way, in recent years, the automatic driving technology of automobiles has been developing rapidly. Therefore, in the near future, it is considered that the level of automatic driving of automobiles will reach the level at which the automobile automatically drives under specific conditions (levels 3 and 4) or the level of fully automatic driving (level 5). In an automobile equipped with such automatic driving technology, even if the driver does not operate the steering wheel 64, the automobile automatically applies a steering angle to the steering wheel 63. For this reason, in an automobile equipped with automatic driving technology, if the steering wheel 64 and the steering wheel 63 are simply mechanically connected, when the automobile automatically applies a steering angle to the steering wheel 63, the steering wheel 64 will rotate. In this case, there may be problems such as the driver's clothes being caught in the steering wheel 64 or the driver's body hitting the rotating steering wheel 64.

[0096] Therefore, in the steering device 62 of this example, an anti-backdrive clutch 1 is provided in the middle of a rotating shaft 65 such as a steering shaft that rotates based on the operation of the steering wheel 64. Specifically, the rotating shaft 65 is configured by connecting an input-side rotating shaft 68 and an output-side rotating shaft 69 that are coaxially arranged with each other via the anti-backdrive clutch 1. When performing automatic driving, the output-side rotating shaft 69 or a rotating member existing on the side of the steering wheel 63 rather than the output-side rotating shaft 69 is rotationally driven using a driving device such as a drive motor or a worm reducer (not shown) to apply a steering angle to the steering wheel 63.

[0097] Furthermore, the basic configuration of the reverse input blocking clutch 1 used in this example is the same as that of the first example of the embodiment. However, the input member 4 that constitutes the reverse input blocking clutch 1 is provided integrally with the input side rotating shaft 68, and the output member 3 that constitutes the reverse input blocking clutch 1 is provided integrally with the output side rotating shaft 69. Therefore, a substantially elliptical columnar cam portion 30 (see FIGS. 1 to 6) is provided at the front end portion of the input side rotating shaft 68, and a cylindrical portion 16 (see FIGS. 1 to 6) having a pressed surface 23 on its inner peripheral surface is provided at the rear end portion of the output side rotating shaft 69. And between the cam portion 30 and the cylindrical portion 16, a pair of engaging members 5 (see FIGS. 1 to 6) are arranged so as to sandwich the cam portion 30 from both sides in the radial direction. Also, a pair of force applying members 6 (see FIGS. 2 to 6) are provided so as to span the pair of engaging members 5.

[0098] In the steering device 62 of this example as described above, when the driver operates the steering wheel 64 and rotational torque is input to the input side rotating shaft 68, the rotation of the input side rotating shaft 68 is transmitted to the output side rotating shaft 69 (output member 3) via the reverse input blocking clutch 1. Then, a steering angle corresponding to the operation amount of the steering wheel 64 is applied to the steered wheels 63.

[0099] On the other hand, when performing automatic driving, when a driving device (not shown) rotationally drives a rotating member that exists on the output side rotating shaft 69 or on the side of the steered wheels 63 closer to the output side rotating shaft 69 than the output side rotating shaft 69, and rotational torque is reversely input to the output side rotating shaft 69, based on the gap 79 formed between the pressed surface 23 and the pair of pressing surfaces 41 by the elasticity of the force applying member 6, the output side rotating shaft 69 is idled. Thereby, it is possible to prevent the rotational torque reversely input from the output side rotating shaft 69 from being transmitted to the input side rotating shaft 68. Therefore, when the vehicle automatically applies a steering angle to the steered wheels 63, it is possible to prevent the steering wheel 64 from rotating regardless of the direction and magnitude of the steering angle. As a result, it is possible to prevent problems from occurring due to the steering wheel 64 rotating without being operated by the driver. Regarding other configurations and operational effects, they are the same as those of the first example of the embodiment.

[0100] [In the 4Example The 4 example of the embodiment of the present invention will be described with reference to FIG. 23. The feature of this example is that the reverse input blocking clutch 1 is applied to the electric curtain opening / closing device 70. Hereinafter, the electric curtain opening / closing device 70 of this example will be specifically described.

[0101] The electric curtain opening / closing device 70 of this example is for electrically opening and closing a curtain 71 attached for the purpose of light shielding, heat insulation, etc. on the indoor side of a window, and includes an endless belt 72, a driving pulley 73, a driven pulley 74, a driving motor 75, and a reverse input blocking clutch 1.

[0102] The endless belt 72 is arranged in a curtain rail (not shown) in a state of being spanned between the driving pulley 73 and the driven pulley 74. The upper part of the curtain 71 is suspended and supported on such an endless belt 72 via a fastener. The driving pulley 73 is rotationally driven by the driving motor 75, and the tooth portion formed on the outer peripheral surface meshes with the tooth portion formed on the inner peripheral surface of the endless belt 72. The driven pulley 74 is rotatably supported in the curtain rail, and the tooth portion formed on the outer peripheral surface meshes with the tooth portion formed on the inner peripheral surface of the endless belt 72. In this example, a reverse input blocking clutch 1 is provided between the driving pulley 73 and the driving motor 75 that rotationally drives the driving pulley 73. Thereby, torque is transmitted from the driving motor 75 to the driving pulley 73, but torque is not transmitted from the driving pulley 73 to the driving motor 75. The basic configuration of the reverse input blocking clutch 1 is the same as the structure of the first example of the embodiment.

[0103] Particularly, in the electric curtain opening / closing device 70 of this example, the input member 4 (see FIGS. 1 to 6) constituting the reverse input blocking clutch 1 is provided integrally with the output shaft of the drive motor 75. Further, the output member 3 (see FIGS. 1 to 6) constituting the reverse input blocking clutch 1 is provided integrally with the pulley shaft 76 having a drive pulley 73 at its tip. For this reason, a substantially elliptical columnar cam portion 30 (see FIGS. 1 to 6) is provided at the tip of the output shaft, and a cylindrical portion 16 (see FIGS. 1 to 6) having a pressed surface 23 on its inner peripheral surface is provided at the base end portion of the pulley shaft 76. And between the cam portion 30 and the cylindrical portion 16, a pair of engaging members 5 (see FIGS. 1 to 6) are arranged so as to sandwich the cam portion 30 from both sides in the radial direction. Also, a pair of force applying members 6 (see FIGS. 2 to 6) are provided so as to span the pair of engaging members 5.

[0104] In the electric curtain opening / closing device 70 of this example having the above-described configuration, when opening and closing the curtain 71, the drive motor 75 is driven, and the output shaft of the drive motor 75 is rotationally driven in a predetermined direction by a predetermined amount. Thereby, the rotation of the output shaft of the drive motor 75 is transmitted to the endless belt 72 via the reverse input blocking clutch 1 and the drive pulley 73. Then, by rotating the endless belt 72, the curtain 71 is opened and closed (horizontally moved). Also, when manually opening and closing the curtain 71, by horizontally moving the curtain 71, the endless belt 72 is rotated. As a result, rotational torque is reversely input to the reverse input blocking clutch 1 from the pulley shaft 76 of the drive pulley 73. However, since there is a gap 79 between the pressed surface 23 and the pair of pressing surfaces 41 due to the elasticity of the force applying member 6, the rotation of the pulley shaft 76 is not transmitted to the output shaft, and the pulley shaft 76 idles. Thus, in this example, it is possible to prevent the rotational torque reversely input from the pulley shaft 76 of the drive pulley 73 from being transmitted to the drive motor 75. Therefore, in the electric curtain opening / closing device 70 of this example, even when power cannot be supplied to the drive motor 75 during a power failure or the like, the curtain 71 can be manually opened and closed with a light force. Regarding other configurations and operational effects, they are the same as those of the first example of the embodiment.

[0105] The 2 example to the 4In the example, an example in which the reverse input blocking clutch according to the first example of the embodiment is applied has been described. However, the reverse input blocking clutch of the present invention can be applied to an engine drive device, a steering device, an electric curtain device, First Example of Reference Example or the reverse input blocking clutch according to the 2 second example can be applied. Further, the reverse input blocking clutch of the present invention can be applied not only to an engine drive device, a steering device, and an electric curtain opening / closing device but also to various mechanical devices. For example, the reverse input blocking clutch of the present invention can be applied to an electric door opening / closing device that opens and closes a door.

[0106] The number of engaging members constituting the reverse input blocking clutch is not limited to two shown in the embodiment, and may be one or three or more. Further, the engagement structure between the input member, the output member, and the engaging member is not limited to the structure shown in the embodiment. As long as the rotation of the input member can be converted into the radial movement of the engaging member, various conventionally known structures can be adopted. Further, the force applying member is not limited to the structure shown in the embodiment, and various structures can be adopted as long as the force can be applied to the engaging member so that a pair of pressing surfaces are separated from the surface to be pressed. Further, the number of force applying members incorporated in the reverse input blocking clutch device is not limited to two, and may be one or three or more. When only one force applying member is provided, the force applying member can be disposed in the through hole formed in the cam portion.

Explanation of Reference Numerals

[0107] 1, 1a, 1b Reverse input blocking clutch 2 Housing 3 Output member 4, 4a, 4b Input member 5, 5a, 5b Engaging member 6 Force applying member 7 Side plate portion 8 Large-diameter cylindrical portion 9 Small-diameter cylindrical portion 10 Inward flange portion 11 Through hole 12 Bolt 13 Fixing member 14 Threaded hole 15 Output shaft portion 16 Cylindrical portion 17 Side plate part 18 Small-diameter part 19 Large-diameter part 20 Small-diameter cylindrical surface part 21 Large-diameter cylindrical surface part 22 Step part 23 Pressed surface 24 Radial needle bearing 25 Outer ring 26 Retainer 27 Needle 28 Seal member 29 Large-diameter shaft part 30, 30a, 30b Cam part 31 Small-diameter shaft part 32 Outward flange part 33 First flat surface part 34 Second flat surface part 35 Connection surface part 36a, 36b Radial rolling bearing 37a, 37b Outer ring 38a, 38b Inner ring 39a, 39b Rolling element 40a, 40b, 40c, 40d Retaining ring 41 Pressing surface 42, 42a, 42b Engaging concave part 43 Bottom surface 44 Side surface part 45 Notch part 46 Locking hole 47, 47a Engaging convex part 48 Shaft body 49 Pin 50 Concave part 51 Concave curved surface part 52 Inclined surface part 53 Engine drive device 54 Engine 55 Starter motor 56 Crankshaft 57 Motor output shaft 58 Pinion 59 Pinion shaft 60 Flywheel 61 Ring gear 62 Steering device 63 Steering wheel 64 Steering wheel 65 Rotation axis 66 Steering gear unit 67 Tie rod 68 Input side rotation axis 69 Output side rotation axis 70 Electric curtain opening / closing device 71 Curtain 72 Endless belt 73 Driving pulley 74 Driven pulley 75 Driving motor 76 Pulley shaft 77 Coil part 78 Locking arm part 79 Gap

Claims

1. An output member having a surface to be pressed on its inner peripheral surface, an input member having a cam portion disposed radially inward of the surface to be pressed and disposed coaxially with the surface to be pressed, at least one engaging member each having a pair of pressing surfaces that face the surface to be pressed and are circumferentially spaced apart from each other, a force applying member that applies a force in a direction in which the pair of pressing surfaces move away from the surface to be pressed to the engaging member, and comprising When the force in the direction of bringing the pair of pressing surfaces acting on the engaging member closer to the surface to be pressed with the input of rotational torque to the input member is greater than the force applied by the force applying member to the engaging member, the engaging member moves radially in the direction of bringing the pair of pressing surfaces closer to the surface to be pressed, and frictionally engages the pair of pressing surfaces with the surface to be pressed, and transmits the rotational torque input to the input member to the output member. On the other hand, when no rotational torque is input to the input member, or when the force in the direction of bringing the pair of pressing surfaces acting on the engaging member closer to the surface to be pressed with the input of rotational torque to the input member is less than or equal to the force applied by the force applying member to the engaging member, a gap is formed between the surface to be pressed and the pair of pressing surfaces based on the force applied by the force applying member to the engaging member, so that torque is not transmitted between the input member and the output member. The input member has a guide portion on the input member side, and the engaging member has a guide portion on the engaging member side. In a free state in which the gap is formed between the surface to be pressed and the pair of pressing surfaces based on the force applied by the force applying member to the engaging member, the guide portion on the input member side and the guide portion on the engaging member side engage without rattling with respect to a first direction that is the direction of the pair of pressing surfaces with respect to the surface to be pressed and a second direction that is orthogonal to the central axis of the input member. The outer peripheral surface of the cam portion is composed of a pair of first flat surface portions disposed on both sides in the short axis direction, a pair of second flat surface portions disposed on both sides in the long axis direction, and a connecting surface portion that connects the long axis direction end portion of the first flat surface portion and the short axis direction end portion of the second flat surface portion. The engaging member has an engaging recess provided on its radially inner surface. The inner surface of the engaging recess is composed of a bottom surface and a pair of side surface portions. The input member side guide portion is constituted by the end portion in the minor axis direction of the cam portion, and the engaging element side guide portion is constituted by the engaging concave portion. In the free state, the bottom surface is in surface contact with the first flat surface portion, and the pair of side surface portions are in surface contact with the connection surface portion. Reverse input blocking clutch.

2. A pair of the engaging elements are provided so as to sandwich the cam portion from the radially outer side. The reverse input blocking clutch according to claim 1.

3. The force applying member is provided so as to span between the pair of the engaging elements. The reverse input blocking clutch according to claim 2.

4. The force applying member is constituted by an elastic member. The reverse input blocking clutch according to any one of claims 1 to 3.

Images