Reverse-input blocking clutch

Abstract

In this reverse-input blocking clutch 1, first and second wedge-shaped spaces 71, 72 having the same direction in which a space width is reduced are formed between a first cam surface 31a and a second cam surface 31b provided on an inner ring 31 constituting an output-side member 3, and an inner peripheral surface 43a of an outer ring 42 constituting a stationary member 4, and one engaging element 5 each is disposed in the wedge-shaped spaces 71, 72. In a state where there is no torque input to an input-side member 2 of the clutch 1, the engaging element 5 (5B) in the first wedge-shaped space 71 receives an elastic restoring force of (an arc-shaped part 6a of) the elastic member 6 and is pushed into a narrow side of the first wedge-shaped space 71 while a clearance C in the circumferential direction is interposed between the engaging element 5 (5A) in the first wedge-shaped space 71 and the engaging element 5 (5B) in the second wedge-shaped space 72.

Description

Reverse input blocking clutch

[0001] This invention relates to a reverse input interruption clutch.

[0002] In Patent Document 1, the applicant has proposed a reverse input blocking clutch configured to transmit torque input to the input side member to the output side member, while blocking (not transmitting to the input side member) reverse input torque input to the output side member. Below, an overview of the conventional reverse input blocking clutch described in Patent Document 1 will be explained based on Figures 7-9. Figure 7 is a cross-sectional view of a conventional reverse input blocking clutch, Figure 8 is a partially enlarged view of Figure 7, and Figure 9 is an exploded perspective view of a conventional reverse input blocking clutch.

[0003] The reverse input blocking clutch 100 described in Patent Document 1 comprises an input shaft 101 as an input-side member to which torque is input, an inner ring 102 as an output-side member capable of outputting the torque, an outer ring 103 as a stationary member that houses the inner ring 102 on its inner circumference while restricting its rotation (rotation around the axis of the input shaft 101), and a plurality of engaging elements (cylindrical rollers) 104 and an elastic member 107 arranged in the annular space between the inner ring 102 and the outer ring 103, wherein the input shaft 101, the inner ring 102 and the outer ring 103 are arranged coaxially.

[0004] In the above reverse input blocking clutch 100, on the outer peripheral surface of the inner ring 102, a first cam surface 102a and a second cam surface 102b inclined with respect to the circumferential direction are provided in series in the circumferential direction. Between both cam surfaces 102a, 102b and the cylindrical inner peripheral surface 103a of the outer ring 103 facing thereto, a first wedge-shaped space 105 and a second wedge-shaped space 106 having the same direction in which the space width (radial width) decreases are respectively formed. One engaging element 104 is arranged in each of the two wedge-shaped spaces 105, 106. In a state where no torque is input to the input shaft 101, two engaging elements 104 arranged continuously in the circumferential direction are in contact with each other. Here, the engaging element 104 (104A) arranged in the first wedge-shaped space 105 is directly subjected to the elastic restoring force of the elastic member 107 and is pushed into the narrow side of the first wedge-shaped space 105, so as to be in contact with the engaging element 104 (104B) arranged in the second wedge-shaped space 106. The engaging element 104B is pushed into the narrow side of the second wedge-shaped space 106 by coming into contact with the engaging element 104A in the circumferential direction.

[0005] As described above, when the engaging elements 104A, 104B are pushed into the narrow sides of the respective wedge-shaped spaces 105, 106, the engaging element 104A bites into the inner peripheral surface 103a of the outer ring 103 and the cam surface 102a of the inner ring 102, and at the same time, the engaging element 104B bites into the inner peripheral surface 103a of the outer ring 103 and the cam surface 102b of the inner ring 102, resulting in a locked state. In this locked state, even if a reverse input torque is input to the inner ring 102, the rotation of the inner ring 102 with respect to the outer ring 103 is restricted, so the reverse input torque is not transmitted to the input shaft 101.

[0006] On the other hand, although not shown in the figure, when torque is input to the input shaft 101, a lock release piece 108 provided to rotate integrally with the input shaft 101 presses the engaging element 104B in the second wedge-shaped space 106 toward the wider side of the second wedge-shaped space 106, and at the same time, the engaging element 104B presses the engaging element 104A in the first wedge-shaped space 105 toward the wider side of the first wedge-shaped space 105, thereby releasing the above locked state. In this unlocked state, the torque input to the input shaft 101 is transmitted to the inner ring 102 (output side member), and the output side member rotates.

[0007] Japanese Patent Application Laid-Open No. 2017-61973

[0008] As described above, in the conventional reverse input blocking clutch 100 shown in Figure 7-9, when there is no torque input to the input shaft 101, the two engaging elements 104 (104A, 104B) arranged in a circumferential direction are in contact with each other. In this state, for example, as shown in Figure 10, when a reverse input torque (here, a counterclockwise reverse input torque) Tr is input to the inner ring 102 as the output side member, the engaging element 104A in the first wedge-shaped space 105 is restricted from moving toward the narrower side of the first wedge-shaped space 105 by the engaging element 104B in the second wedge-shaped space 106. In addition, the elastic restoring force of the elastic member 107 acts on the engaging element 104B via the engaging element 104A, pressing it toward the narrower side of the second wedge-shaped space 106.

[0009] Therefore, when the reverse input torque Tr described above is applied to the inner ring 102, the engaging element 104B in the second wedge-shaped space 106 moves relative to the narrower side of the space 106 and engages with the second cam surface 102b of the inner ring 102 and the inner circumferential surface 103a of the outer ring 103, while the engaging element 104A in the first wedge-shaped space 105 moves relative to the narrower side of the space 105, lagging behind the engaging element 104B (engaging with the first cam surface 102a and the inner circumferential surface 103a). Furthermore, if the rotation of the inner ring 102 is restricted when the engaging element 104B in the second wedge-shaped space 106 engages with the second cam surface 102b and the inner circumferential surface 103a, the engaging element 104A in the first wedge-shaped space 105 may not be able to move sufficiently relative to the narrower side of the space 105, potentially resulting in insufficient engagement of the engaging element 104A with the first cam surface 102a and the inner circumferential surface 103a. In this case, the load is concentrated in the area of ​​the second cam surface 102b (and inner circumferential surface 103a) that has been elastically deformed by the engaging element 104B (see the dashed line in Figure 10), and even if a reverse input torque Tr below the design allowable value is input to the inner ring 102, there is a risk that the second cam surface 102b (and the inner ring 102 having it) may be damaged.

[0010] In view of the above circumstances, the present invention aims to prevent as much as possible the concentration of load on a part of the output side member (second cam surface) when reverse input torque is input, thereby realizing a reverse input blocking clutch that can stably exhibit the desired reverse input blocking performance.

[0011] The present invention, devised to achieve the above objective, comprises an input-side member to which torque is input, an output-side member capable of outputting the above torque, a stationary member housing the output-side member on its inner circumference in a rotationally restricted state, and an engaging element and an elastic member arranged in the annular space between the output-side member and the stationary member, wherein first and second wedge-shaped spaces are formed between the circumferentially connected first and second cam surfaces on the outer circumferential surface of the output-side member and the cylindrical inner circumferential surface of the stationary member, with the same direction in which the spatial width decreases, and one engaging element is arranged in each of these first and second wedge-shaped spaces, characterized in that, when there is no torque input to the input-side member, the engaging element arranged in the first wedge-shaped space is pushed into the narrower side of the first wedge-shaped space by the elastic restoring force of the elastic member, with a circumferential gap between the engaging element arranged in the first wedge-shaped space and the engaging element arranged in the second wedge-shaped space.

[0012] In the clutch unit according to the present invention having the above configuration, when a reverse input torque is applied to the output side member, the engaging elements arranged in the first and second wedge-shaped spaces, respectively, can be moved as follows. When there is no torque input to the input side member, the engaging element in the first wedge-shaped space is pushed to the narrower side of the first wedge-shaped space by the elastic restoring force of the elastic member. Therefore, when a reverse input torque (a reverse input torque in the direction opposite to the elastic restoring force of the elastic member) is applied to the output side member, the engaging element in the first wedge-shaped space engages with the output side member and the stationary member before the engaging element in the second wedge-shaped space. As the reverse input torque applied to the output side member increases, the engaging element in the first wedge-shaped space moves relative to the narrower side of the space while elastically deforming the first cam surface and cylindrical surface, and comes into contact with the engaging element in the second wedge-shaped space, pressurizing the engaging element towards the narrower side of the second wedge-shaped space. Consequently, the engaging element in the second wedge-shaped space engages with the output-side member (the second cam surface provided on it) and the stationary member (the cylindrical surface provided on it).

[0013] In other words, in the reverse input blocking clutch according to the present invention, when a reverse input torque is applied to the output side member, the engaging elements in the first wedge-shaped space and then the engaging elements in the second wedge-shaped space can engage with the output side member and the stationary member in that order. As a result, the reverse input torque applied to the output side member can be received by both the first cam surface and the second cam surface. Therefore, damage to the output side member caused by load concentration on the second cam surface, which was a concern in the conventional reverse input blocking clutch 100 shown in Figure 7-9, can be prevented, and the desired reverse input blocking performance can be stably achieved.

[0014] In order to properly enjoy the advantages of the present invention described above, the circumferential spacing to be interposed between the engaging element arranged in the first wedge-shaped space and the engaging element arranged in the second wedge-shaped space when there is no torque input to the input-side member shall have a circumferential length of 0.1° to 5°.

[0015] In the reverse input blocking clutch according to the present invention, a configuration can be adopted in which a first wedge-shaped space and a second wedge-shaped space are arranged sequentially in the circumferential direction on one side of the elastic member, and a first wedge-shaped space and a second wedge-shaped space are arranged sequentially in the circumferential direction on the other side of the elastic member. In this case, the transmission blocking function can be performed for reverse input torque in both forward and reverse directions, thereby increasing the versatility of the reverse input blocking clutch.

[0016] The elastic member described above can be, for example, a C-shaped spring.

[0017] From the above, according to the present invention, it is possible to prevent as much as possible the concentration of load on a part of the output side member (second cam surface) when reverse input torque is input, thereby realizing a reverse input blocking clutch that can stably exhibit the desired reverse input blocking performance.

[0018] This is a front view of a reverse input blocking clutch according to an embodiment of the present invention. This is a cross-sectional view taken along the line A-A in Figure 1. This is a cross-sectional view taken along the line B-B in Figure 1. This is a partially enlarged view of Figure 3A. This is an exploded perspective view of the reverse input blocking clutch shown in Figure 1. This is a schematic perspective view of the elastic member incorporated into the reverse input blocking clutch of this embodiment. This is a schematic perspective view for explaining the arrangement of the elastic member and the engaging element shown in Figure 5A. This is a diagram for explaining how the engaging element engages when a reverse input torque is applied to the output shaft of the reverse input blocking clutch shown in Figure 1. This is a schematic cross-sectional view of a conventional reverse input blocking clutch. This is a partially enlarged view of Figure 7. This is an exploded perspective view of a conventional reverse input blocking clutch. This is a diagram for explaining the problems of a conventional reverse input blocking clutch.

[0019] Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 6.

[0020] Figure 1 is a front view of a reverse input blocking clutch 1 according to an embodiment of the present invention, Figure 2 is a cross-sectional view taken along the line A-A in Figure 1, Figure 3A is a cross-sectional view taken along the line B-B in Figure 2, Figure 3B is a partially enlarged view of Figure 3A, and Figure 4 is an exploded perspective view of the reverse input blocking clutch 1. This reverse input blocking clutch 1 comprises an input-side member 2 to which torque is input, an output-side member 3 to which the torque is output, a stationary member 4, a plurality of engaging elements 5, and an elastic member 6. In the following description, "axial direction," "radial direction," and "circumferential direction" refer to the direction parallel to the axis of the input shaft 21 constituting the input-side member 2, the radial direction of a circle centered on the axis, and the circumferential direction of a circle centered on the axis, respectively.

[0021] The input-side member 2 comprises an input shaft 21 and a lock release member 22 that rotates together with the input shaft 21. The input shaft 21 has a small-diameter shaft portion 21a and a large-diameter shaft portion 21b, and a pair of parallel planar portions 21c are formed on the outer circumference of the output-side (left side of the paper in Figure 2) end of the large-diameter shaft portion 21b. The lock release member 22 integrally has an annular portion 22a in which a non-circular central hole 22b is formed, and a plurality (two) of columnar portions 22c that extend axially from the outer circumference of the annular portion 22a and are arranged at equal intervals in the circumferential direction, and rotates together with the input shaft 21 by fitting the annular portion 22a onto the outer circumference of the portion of the large-diameter shaft portion 21b in which the planar portions 21c are formed.

[0022] The output-side member 3 integrally comprises an inner ring 31 (a functional part) and an output shaft 32 (a functional part), and is arranged coaxially with the input-side member 2. An input shaft insertion hole 33 is formed in the portion of the output-side member 3 where the inner ring 31 is provided, and a portion of the input shaft 21 is inserted into this input shaft insertion hole 33.

[0023] The stationary member 4 has a side plate 41 that also functions as a mounting bracket for attaching the reverse input blocking clutch 1 to the object to be mounted, and an outer ring 42 fixed to the side plate 41. The outer ring 42 integrally has a cylindrical tube portion 43, a flange portion 44 provided at the input side end (right side of the paper in Figure 2) of the tube portion 43, and a bearing portion 45 provided at the output side end (left side of the paper in Figure 2) of the tube portion 43, and the flange portion 44 has a plurality (in this case, three) of recesses 44a provided at intervals in the circumferential direction. The side plate 41 has a plurality (in this case, three) of axially extending protrusions 41a provided at intervals in the circumferential direction, and the outer ring 42 and the side plate 41 are joined and integrated by fitting each protrusion 41a into the recesses 44a provided in the flange portion 44 of the outer ring 42 and bending it.

[0024] An annular space 7 is formed between the inner circumferential surface 43a of the cylindrical portion 43 of the outer ring 42 and the outer circumferential surface of the inner ring 31 facing it, and a cylindrical roller and an elastic member 6 as an engaging element 5 are arranged in this annular space 7. The inner circumferential surface 43a of the outer ring 42 is formed as a cylindrical surface with a constant diameter, while the outer circumferential surface of the inner ring 31 is formed as a non-circular shape by providing a first cam surface 31a and a second cam surface 31b that are inclined with respect to the circumferential direction and are arranged in a continuous manner in the circumferential direction. Four sets of the circumferentially continuous first cam surface 31a and second cam surface 31b are provided in the circumferential direction. The first cam surface 31a and the second cam surface 31b each form a first wedge-shaped space 71 and a second wedge-shaped space 72 with respect to the inner circumferential surface 43a of the opposing outer ring 42, with the same direction in which the space width (radial width) decreases. In other words, the first and second wedge-shaped spaces 71 and 72, which are continuous in the circumferential direction, are arranged such that the wider part of the second wedge-shaped space 72 is connected to the narrower part of the first wedge-shaped space 71. One engaging element 5 is placed in each of the wedge-shaped spaces 71 and 72. Hereafter, when distinguishing between the engaging element 5 placed in the first wedge-shaped space 71 and the engaging element 5 placed in the second wedge-shaped space 72, the former will be referred to as "engaging element 5A" and the latter as "engaging element 5B".

[0025] In the annular space 7 described above, two arc-shaped first housing spaces 73 are provided at circumferential intervals (here at 180° intervals) where the elastic member 6 (or its pressurizing portion 6b) is positioned. In this embodiment, a first wedge-shaped space 71 and a second wedge-shaped space 72 are arranged sequentially in a circumferential direction on one circumferential side of each first housing space 73, and a first wedge-shaped space 71 and a second wedge-shaped space 72 are arranged sequentially in a circumferential direction on the other circumferential side of each first housing space 73. In other words, the first housing space 73 is provided between two circumferentially adjacent first wedge-shaped spaces 71, 71. Furthermore, an arc-shaped second housing space 74 is provided between two circumferentially adjacent second wedge-shaped spaces 72, 72, and the column portion 22c of the lock release member 22 is positioned in this second housing space 74.

[0026] In this embodiment, a C-shaped spring, as shown in enlarged view in Figures 5A and 5B, is used as the elastic member 6. This C-shaped spring consists of an arc-shaped portion 6a extending circumferentially to form a substantially C shape, and a pair of pressurizing portions 6b extending axially from one end and the other end of the circumferential portion 6a. When using the C-shaped spring, the arc-shaped portion 6a is positioned on the axially outer side of the engaging element 5 in an elastically reduced diameter state, and the pair of pressurizing portions 6b are positioned in the first housing space 73. In the absence of torque input to the input-side member 2 (input shaft 21), the elastic restoring force of the arc-shaped portion 6a pushes the engaging elements 5, 5 in the first wedge-shaped spaces 71 adjacent to one and the other circumferential sides of the first housing space 73 toward the narrower side (second wedge-shaped space 72 side) of the space 71. As a result, the engaging element 5 (5A) in the first wedge-shaped space 71 engages with both the first cam surface 31a of the inner ring 31 and the inner circumferential surface 43a of the outer ring 42, thereby locking the rotation of the inner ring 31 (and the output-side member 3 comprising it), and interrupting torque transmission from the output-side member 3 to the input-side member 2.

[0027] In the reverse input blocking clutch 1 of this embodiment, when there is no torque input to the input shaft 21 as described above, and the engaging element 5 (5A) positioned in the first wedge-shaped space 71 is pushed into the narrower side of the first wedge-shaped space 71 by the elastic restoring force of the elastic member 6, a circumferential gap C is interposed between the engaging elements 5A and 5B positioned in the circumferentially continuous first and second wedge-shaped spaces 71 and 72, respectively, and the two engaging elements 5A and 5B are not in contact with each other in the circumferential direction. The behavior of the engaging elements 5A and 5B when a reverse input torque is input to the output side member 3 (output shaft 32) when such a structure is adopted will be explained with reference to Figure 6. Note that in Figure 6, the input shaft 21 and the like have been omitted from the viewer's perspective.

[0028] First, when there is no torque input to the input shaft 21, the engaging element 5A in the first wedge-shaped space 71 is pushed to the narrower side of the first wedge-shaped space 71 by the elastic restoring force of the elastic member 6. Therefore, when a reverse input torque Tr (in this case, a counterclockwise reverse input torque Tr) is input to the output shaft 32, the engaging element 5A engages with the inner ring 31 (the first cam surface 31a) and the outer ring 42 (the inner circumferential surface 43a) before the engaging element 5B in the adjacent second wedge-shaped space 72. As the reverse input torque Tr input to the output shaft 32 increases, the engaging element 5A in the first wedge-shaped space 71 moves relative to the narrower side of the first wedge-shaped space 71, as shown by the dashed line in Figure 6, while elastically deforming the first cam surface 31a and the inner circumferential surface 43a of the outer ring 42. This causes the engaging element 5A to contact the engaging element 5B in the second wedge-shaped space 72 and push the engaging element 5B towards the narrower side of the second wedge-shaped space 72. Consequently, the engaging element 5B engages with the inner ring 31 (specifically the second cam surface 31b provided on it) and the outer ring 42 (specifically its inner circumferential surface 43a).

[0029] In short, in the reverse input blocking clutch 1 of this embodiment, when a reverse input torque Tr is input to the output shaft 32, the engaging elements 5 can be engaged with both the inner ring 31 (on the output side member 3) and the outer ring 42 (on the stationary member 4) in the order of engaging element 5A in the first wedge-shaped space 71 → engaging element 5B in the second wedge-shaped space 72. In this case, the reverse input torque Tr input to the output shaft 32 can be received by both the first cam surface 31a and the second cam surface 31b provided on the outer circumferential surface of the inner ring 31. Therefore, damage to the output side member 3 caused by load concentration on the second cam surface, which was a concern in conventional reverse input blocking clutches 100 (see Figure 7-9) where the reverse input torque input to the output shaft may be received only by the second cam surface, can be prevented. This makes it possible to realize a reverse input blocking clutch 1 with excellent durability and long lifespan.

[0030] Furthermore, if the circumferential spacing C provided between the engaging elements 5A and 5B when there is no torque input to the input shaft 21 is too small, it will not be possible to resolve the problem of load concentration on the second cam surface that can occur in conventional reverse input blocking clutches 100. Also, if the circumferential length of the circumferential spacing C is too large, the engaging element 5A in the first wedge-shaped space 72 will have difficulty contacting the engaging element 5B in the adjacent second wedge-shaped space 73, so there is a risk that the engaging element 5B will not engage with the second cam surface 31b of the inner ring 31 and the inner circumferential surface 43a of the outer ring 42. For this reason, it is preferable that the circumferential spacing C provided between the engaging elements 5A and 5B when there is no torque input to the input shaft 21 has a circumferential length of 0.1° to 5°.

[0031] On the other hand, when torque is applied to the input shaft 21, first the column portion 22c of the unlocking member 22, which rotates integrally with the input shaft 21, contacts the engaging element 5B in the second wedge-shaped space 72, pushing the engaging element 5B towards the wider side of the second wedge-shaped space 72. As the amount of rotation of the input shaft 21 (amount of torque applied to the input shaft 21) increases, the engaging element 5B contacts the engaging element 5A in the first wedge-shaped space 71, pushing the engaging element 5A towards the wider side of the first wedge-shaped space 71 against the elastic restoring force of the elastic member 6. As a result, the engagement of the engaging elements 5A and 5B with respect to the inner ring 31 and outer ring 42 is resolved, and the rotation of the input shaft 21 is transmitted to the inner ring 31 (and the output side member 3 having it), causing the input side member 2 and the output side member 3 to rotate integrally.

[0032] As described above, the reverse input blocking clutch 1 is configured such that a first wedge-shaped space 71 and a second wedge-shaped space 72 are arranged sequentially in the circumferential direction on one side of the first housing space 73 where a C-shaped spring (pressure portion 6b) as an elastic member 6 is arranged, and the first wedge-shaped space 71 and the second wedge-shaped space 72 are arranged sequentially in the circumferential direction on the other side of each first housing space 73. Therefore, it can perform a transmission blocking function for reverse input torque Tr in both forward and reverse directions, making it highly versatile. In the embodiment shown in Figure 3A, the engaging elements 5 (5A, 5B) located in the first quadrant in the upper right and the third quadrant in the lower left of the paper engage with the inner ring 31 and the outer ring 42, thereby blocking the transmission of the counterclockwise reverse input torque Tr input to the output side member 3 to the input side member 2. The engaging elements 5 located in the second quadrant in the upper left and the fourth quadrant in the lower right of the paper engage with the inner ring 31 and the outer ring 42, thereby blocking the transmission of the clockwise reverse input torque input to the output side member 3 to the input side member 2.

[0033] The reverse input blocking clutch 1 according to an embodiment of the present invention has been described above, but the reverse input blocking clutch 1 can be modified as appropriate without departing from the spirit of the present invention.

[0034] For example, in addition to the C-shaped spring described above, a compression coil spring as described in Patent Document 1 can also be used as the elastic member 6. However, if a C-shaped spring is used, the portion that pressurizes the engaging element 5 in the circumferential direction (pressurizing portion 6b) is compact, which makes it possible to make the first housing space 73 in the annular space 7 in which the pressurizing portion of the elastic member 6 is housed, and consequently the entire reverse input blocking clutch 1, more compact.

[0035] Furthermore, the present invention can be implemented in various forms without departing from its essence. The scope of the present invention is indicated by the claims, and further includes the equivalent meanings set forth in the claims, and all modifications within the scope.

[0036] 1 Reverse input blocking clutch 2 Input side member 3 Output side member 4 Stationary member 5 Engaging element 6 Elastic member 7 Annular space 21 Input shaft 22 Unlocking member 22c Column 31 Inner ring 31a First cam surface 31b Second cam surface 41 Side plate 42 Outer ring 43a Inner circumferential surface 71 First wedge-shaped space 72 Second wedge-shaped space 73 First housing space 74 Second housing space C Circumferential spacing

Claims

1. A reverse input blocking clutch comprising: an input-side member to which torque is input; an output-side member capable of outputting the torque; a stationary member housing the output-side member on its inner circumference in a rotationally restricted state; and an engaging element and an elastic member disposed in the annular space between the output-side member and the stationary member, wherein first and second wedge-shaped spaces are formed between first and second cam surfaces provided circumferentially on the outer circumferential surface of the output-side member and a cylindrical surface provided on the inner circumference of the stationary member, with the same direction in which the spatial width decreases, and one engaging element is disposed in each of these first and second wedge-shaped spaces, characterized in that, when there is no torque input to the input-side member, the engaging element disposed in the first wedge-shaped space is pushed to the narrower side of the first wedge-shaped space by the elastic restoring force of the elastic member, with a circumferential gap between the engaging element disposed in the first wedge-shaped space and the engaging element disposed in the second wedge-shaped space.

2. The reverse input shutoff clutch according to claim 1, wherein the interval has a circumferential length of 0.1° or more and 5° or less.

3. The reverse input shutoff clutch according to claim 1, wherein the first wedge-shaped space and the second wedge-shaped space are arranged sequentially in a circumferential direction on one side of the elastic member, and the first wedge-shaped space and the second wedge-shaped space are arranged sequentially in a circumferential direction on the other side of the elastic member.

4. The reverse input blocking clutch according to claim 1, wherein the elastic member is a C-shaped spring.

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