Reverse input cutoff clutch

Abstract

To provide a reverse input cutoff clutch in which a clutch strength is improved and a size is reduced to a compact size.SOLUTION: A clutch includes: an away movement mechanism in which an input of a torque into an input member moves a first brake member and a second brake member in a direction closer to a relatively radial direction, and the first brake member and the second brake member are moved in a direction away from a stationary member; and a transmission mechanism for transmitting the torque input in the input member in a state where the first brake member and the second brake member are away from the stationary member to the output member. A cam member is interposed between the first brake member and the second brake member, a rotation of a reverse input of torque into the output member is transmitted to the cam member, the first brake member and the second brake member are moved away in a radial direction to each other, the first brake member and the second brake member are pressed against the stationary member, and the transmission of the torque from the output member to the input member is cut off.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a reverse input disconnecting clutch. [Background technology]

[0002] As shown in Fig. 18, the reverse input cutoff clutch is a clutch that transmits the rotation of the input member 2 to the output member 3 when input torque is applied, and prevents the input member 2 from rotating in response to reverse input torque. Such a reverse input cutoff clutch is disclosed, for example, in Patent Document 1.

[0003] In the reverse input cutoff clutch described in Patent Document 1, when torque is reversely input to the output member 3, the output member 3 moves a pair of engaging members (engagements) 5, 5 radially outward, thereby pressing the pressing surfaces 11, 11 of the engaging members 5, 5 against the pressed surface 10 (inner diameter surface consisting of a cylindrical surface) of the pressed member 4, thereby cutting off the torque. Furthermore, when torque is input to the input member 2, the pair of engaging members 5, 5 move radially inward, thereby moving the pressing surfaces 11, 11 of the engaging members 5, 5 away from (separating from) the pressed surface 10 of the pressed member 4. The torque input to the input member 2 is transmitted to the output member 3 via the engaging members 5, 5. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 172558 Summary of the Invention [Problem to be solved by the invention]

[0005] In the device described in Patent Document 1, a gap is provided between the output member 3 and the engaging members 5, 5 to allow the engaging members 5, 5 to separate from the pressed member 4. In other words, there is a so-called backlash (play). The size of the backlash is determined by the size of the gap and the distance from the center of rotation of the contact portion X of the output member 3 and the engaging members 5, 5. In this case, the distance r (see FIG. 19) from the center of rotation O of the contact portion X is short, and the backlash that occurs is large. If the "backlash" is large, it may cause abnormal noise.

[0006] That is, in the clutch described in Patent Document 1, when rotational torque is input to the input member 2, the input-side engaging portion 7 rotates inside the input-side engaged portion 12 in the rotational direction of the input member 2. Then, the radially inner surface of the input-side engaging portion 7 presses the radially inner portion of the inner surface of the input-side engaged portion 12 radially inward. In this case, each engaging element 5 elastically contracts the pair of springs 18, moving in a direction away from the pressed surface 10. Then, the output-side engaged surface 16 of each engaging element 5 comes into surface contact with both sides of the output-side engaging portion 9 of the output member 3 in the lateral direction. As a result, the rotational torque input to the input member 2 is transmitted to the output member 3 via the pair of engaging elements 5.

[0007] When a rotational torque is reversely input to the output member 3, the reverse input cutoff clutch 1 moves each of the engaging elements 5 in a direction approaching the pressed surface 10, regardless of the rotational direction of the output member 3. Then, the rotational torque reversely input to the output member 3 is completely cut off and not transmitted to the input member 2, or only a portion of the rotational torque reversely input to the output member 3 is transmitted to the input member 2, with the remainder being cut off. In other words, when a rotational torque is reversely input to the output member 3, the output-side engaging portion 9 rotates in the rotational direction of the output member 3, inside the pair of output-side engaged portions 13. Then, the corners of the output-side engaging portion 9 press the output-side engaged surface 16 radially outward. As a result, each of the engaging elements 5 moves in a direction approaching the pressed surface 10, and the engaging elements 5 move radially outward, away from each other, based on their engagement with the output member 3.

[0008] In order to cut off the reverse input, the reverse input torque must be smaller than the brake torque. In other words, the following equation 1 must be satisfied:

number

[0009] In this case, it is necessary to reduce the distance r from the contact point X between the output member 2 and the engaging member 5 to the center of rotation O. However, reducing the distance r increases the load acting on the output member 3, resulting in durability problems. Furthermore, to satisfy the relationship of equation 1, if the distance from the center of rotation O to the contact point C (see FIG. 18) between the engaging member 5 and the pressed member 4 is R (see FIG. 19), then the distance R needs to be increased. However, increasing the distance R increases the outer diameter of the reverse input cutoff clutch, making it impossible to achieve compactness, making it difficult to install, and increasing the weight.

[0010] SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a reverse input cutoff clutch that has increased clutch strength and is compact. [Means for solving the problem]

[0011] The reverse input disconnect clutch of the present invention is a reverse input disconnect clutch having an input member to which torque is input, an output member to which torque is output, a first braking member and a second braking member that are capable of reciprocating in a radial direction, and a stationary member arranged radially outside the first braking member and the second braking member, and further comprising a separating movement mechanism that moves the first braking member and the second braking member in a direction to move them closer to each other in the radial direction when torque is input to the input member, and moves the first braking member and the second braking member in a direction to move them away from the stationary member; and a transmission mechanism that transmits torque input to the input member to the output member while the second braking member is spaced apart from the stationary member, wherein a cam member is interposed between the first braking member and the second braking member, and when torque is input in reverse to the output member, the rotational motion is transmitted to the cam member, causing the first braking member and the second braking member to move in a direction separating them radially from each other, and the first braking member and the second braking member are pressed against the stationary member, thereby blocking the transmission of torque from the output member to the input member.

[0012] According to the reverse input cutoff clutch of the present invention, when torque is input to the input member, the pair of brake members separate from the stationary member. In this separated state, the torque input to the input member is transmitted to the output member, causing the output member to rotate. Furthermore, when torque is input reversely to the output member, the cam member rotates, causing the first and second brake members to separate relatively. This presses the first and second brake members against the stationary member, blocking the transmission of torque from the output member to the input member. The first and second brake members separate relatively by rotation of the cam member interposed between the first and second brake members. At this time, the cam member restricts the first and second brake members from approaching each other, effectively preventing the pair of brake members from separating from the stationary member. Furthermore, when the first and second brake members are relatively separated, the end of the cam member facing the first brake member contacts the first brake member, the end of the cam member facing the second brake member contacts the second brake member, and if the end of the cam member facing the first brake member rotates counterclockwise, the end of the cam member facing the second brake member also rotates counterclockwise. In this case, the end of the cam member facing the first brake member presses the first brake member toward the opposite side of the second brake member, and the end of the cam member facing the second brake member presses the second brake member toward the opposite side of the first brake member. Therefore, by setting the distance between the first contact portion on the cam member side that contacts the first brake member and the second contact portion on the cam member side that contacts the second brake member relatively long, the angle of rotation of the cam member between the first and second brake members is reduced, thereby reducing backlash of the output member. Furthermore, the load acting on the cam member can be reduced, thereby increasing the strength of the clutch.

[0013] Furthermore, even if the distance from the contact point between one braking member and the cam member to the rotation center O is long, the reverse input torque can be made smaller than the braking torque without increasing the distance from the rotation center O to the braking member and the stationary member. As a result, the outer diameter of this clutch does not need to be large.

[0014] The output member has an output shaft portion disposed coaxially with the axis of the input shaft portion of the input member, and an arm portion extending radially from the output shaft portion, and the cam member has a cam main body portion extending radially and having one radial end connected to the radially outer diameter side end of the arm portion of the output member, and a protrusion portion provided on the cam main body portion and disposed between the first braking member and the second braking member, and can be configured so that when torque is input reversely to the output member, the connecting portion of the arm portion swings around the output shaft portion of the output member, and the first contact portion and second contact portion of the protrusion portion press against the brake member pressed surfaces of the first braking member and the second braking member, respectively, and move in a direction radially away from each other.

[0015] With this configuration, the output member has an output shaft portion that is coaxial with the input shaft portion of the input member, allowing the output member to rotate stably without wobbling when torque is input to the input member. Furthermore, when torque is input in reverse to the output member, the connecting portion of the arm portion of the cam main body swings around the output shaft portion of the output member, causing the pair of first and second contact portions of the protrusion to press the first and second brake members, respectively, and move in a direction away from each other in the radial direction. This allows the first and second brake members to slide stably in a direction away from each other, i.e., radially outward. When the first and second brake members slide in a direction away from each other, they are pressed against the stationary member, thereby blocking the transmission of torque from the output member to the input member. This allows the state in which torque transmission to the input member is blocked to be stably achieved.

[0016] It is preferable that an intermediate portion between the first contact portion and the second contact portion is disposed at a position radially spaced from the rotation center of the input shaft of the input member, the first contact portion and the second contact portion of the cam member have different distances to the rotation center of the input shaft of the input member, or the first contact portion is disposed on the opposite side of the second contact portion with respect to a perpendicular line that passes through the rotation center of the cam member and is perpendicular to the pressed surface of the brake member.Furthermore, it is preferable that the first braking member and the second braking member swing around one radial end side, and the swing center is disposed on the opposite side of the intermediate portion between the first contact portion and the second contact portion with respect to a perpendicular line that passes through the rotation center of the input shaft and is perpendicular to the pressed surface of the brake member.Furthermore, it is preferable that a connecting portion between the arm portion of the output member and the cam member is disposed radially outward from the rotation center of the cam member. Here, the intermediate portion between the first contact portion and the second contact portion refers to the midpoint of the line segment connecting the first contact portion and the second contact portion.

[0017] This increases the frictional force at the contact portion (contact surface) between the stationary member and one of the braking members, thereby enabling a self-amplifying increase in braking torque. This allows the braking member to effectively generate a torque transmission blocking force to the input member. Furthermore, by arranging the connecting portion between the arm portion of the output member and the cam member radially outward from the center of the protrusion of the cam member, the rotation angle of the output member at the position where rotation of the cam member is restricted is reduced, reducing backlash in the output member and enabling stable torque blocking.

[0018] The first braking member and the second braking member may be provided with opposing protrusions at one radial end thereof, the opposing surfaces of the protrusions being cylindrical, and when torque is input to the input member, the protrusions come into contact with each other, and the first braking member and the second braking member swing toward each other about the protrusion contact point as a fulcrum, so that the first braking member and the second braking member move away from the stationary member, and the first braking member and the second braking member can be configured to be rotatable about a support shaft. The protrusion of the cam member may be configured as a pair of convex portions spaced apart in the radial direction. Furthermore, it is preferable that the input member and the output member are rotatably supported relative to the stationary member. [Effects of the Invention]

[0019] In the present invention, the backlash of the output member can be reduced, and the load acting on the cam member can be reduced, thereby increasing the strength of the clutch. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 2 is a simplified exploded perspective view of the reverse input cutoff clutch according to the present invention. [Figure 2] FIG. 2 is a vertical cross-sectional view of the reverse input cutoff clutch shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] 2 is a simplified diagram of the reverse input disconnect clutch shown in FIG. 1 as viewed from the output side. [Figure 5] 2 is a simplified diagram of the reverse input disconnect clutch shown in FIG. 1 as viewed from the output side where torque is input to the input member. [Figure 6] 2 is a simplified diagram of the reverse input cutoff clutch shown in FIG. 1 as viewed from the input side when torque is reversely input to the output member. [Figure 7] 2A and 2B show a state in which torque is reversely input to the output member of the reverse input cutoff clutch shown in FIG. 1, where FIG. 2A is a cross-sectional view and FIG. 2B is an enlarged cross-sectional view of a main portion. [Figure 8] FIG. 10 is a simplified exploded perspective view showing a first modified example of the reverse input cutoff clutch. [Figure 9] 9 is a simplified diagram of the reverse input cutoff clutch shown in FIG. 8, viewed from the input side when torque is reversely input to the output member. [Figure 10] 9 is a simplified diagram of the reverse input disconnect clutch shown in FIG. 8 as viewed from the output side where torque is input to the input member. [Figure 11] FIG. 10 is a simplified cross-sectional view showing a second modified example of the reverse input cutoff clutch. [Figure 12] FIG. 10 is an exploded perspective view showing a third modified example of the reverse input cutoff clutch. [Figure 13] FIG. 13 is a vertical cross-sectional view of the input cutoff clutch shown in FIG. [Figure 14] FIG. 14 is a cross-sectional view taken along line BB in FIG. [Figure 15] FIG. 10 is an exploded perspective view showing a fourth modified example of the reverse input cutoff clutch. [Figure 16] FIG. 16 is a vertical cross-sectional view of the input cutoff clutch shown in FIG. [Figure 17] 17 is a cross-sectional view taken along line CC in FIG. 16. [Figure 18] 1 is a simplified diagram showing a conventional reverse input cutoff clutch in a state where a reverse torque is input to an output member. [Figure 19] FIG. 19 is an enlarged view of a main part of FIG. 18. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 17. FIG. 1 shows a simplified perspective view of a reverse input cutoff clutch according to the present invention, FIG. 2 shows a longitudinal cross-sectional view of the reverse input cutoff clutch, FIG. 3 shows a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a simplified view of the reverse input cutoff clutch as seen from the output side. The reverse input cutoff clutch is a reverse input cutoff clutch having an input member 21 to which torque is input, an output member 22 to which torque is output, a pair of first and second braking members 23A and 23B capable of reciprocating in the radial direction, and a stationary member 24 disposed radially outward so as to cover the first and second braking members 23A and 23B. Here, the radial direction refers to a direction perpendicular to the rotation axis. The device also includes a separating mechanism M1 that moves the pair of first and second braking members 23A, 23B in a direction radially approaching each other when torque is input to the input member 21, thereby moving the first and second braking members 23A, 23B in a direction away from the stationary member 24, and a transmission mechanism M2 that transmits the torque input to the input member 21 to the output member when the first and second braking members 23, 23 are away from the stationary member 24.

[0022] The input member 21 includes an input shaft portion 21a and a main body portion 21b connected to one end surface of the input shaft portion 21a. The main body portion 21b has a disk portion 27 and a pair of bulging portions 28A, 28B provided on the opposite side of the disk portion 27 from the input shaft portion. The bulging portions 28A, 28B are provided at positions 180° opposite each other with respect to the center of the disk portion 27. The bulging portions 28A, 28B are provided on the outer peripheral edge side of the disk portion 27, and their inner diameter portions are flat surfaces 29a, 29a that face each other, and their outer diameter surfaces are arcuate surfaces 29b, 29b that are integrated with the outer peripheral edge of the disk portion 27.

[0023] The output member 22 has an output shaft portion 22a and an arm portion 22b extending radially outward from the axial end portion (the end portion on the input member side) of the output shaft portion 22a, and is connected to a cam member 30. The cam member 30 has a flat plate-shaped main body portion 30a extending radially, and a protrusion portion 30b provided on the end surface of the main body portion 30a on the input member side. Here, the axial direction is the direction along the central axis of the output shaft portion 22a, and is the direction of the center line of rotational motion when an object rotates. The protrusion 30b has a rectangular parallelepiped shape and is not provided on one radially outer side of the main body 30a. The arm 22b of the output member 22 and the cam main body 30a of the cam member 30 are connected to each other via the support shaft 31 that forms a connecting portion, with the arm 22b of the output member 22 and the back side (opposite the input member side) of the cam main body 30a of the cam member 30 overlapping each other. The output member 22 and the cam member 30 are rotatable via the support shaft 31, and the output member 22 and the cam member 30 swing around the support shaft 31. The arm 22b and the cam main body 30a have through holes 31a, 31a, into which the support shaft 31 is fitted.

[0024] The braking members 23A, 23B each have a flat plate-shaped main body 32 and a protrusion 33 protruding inward from one longitudinal end of the main body 32. When placed over the protrusion 33, the braking members 23A, 23B are rotatable via a support shaft 34 that forms the center of oscillation, and the braking members 23A, 23B oscillate around the support shaft 34. When the braking members 23A, 23B are connected, a gap S1 (see FIG. 6) is provided between the main bodies 32, and the protrusion 30b of the cam member 30 is fitted into this gap S1. Each protrusion 33 is provided with a through hole 33a, into which the support shaft 34 is fitted.

[0025] Furthermore, the braking members 23A, 23B are interposed between the bulging portions 28A, 28B of the input member 21. When torque is input to the input member 21 in the direction of arrow A1 shown in FIG. 5, the input shaft portion 21a of the input member 21 rotates in the direction of arrow A1 about its axis, and the pair of bulging portions 28A, 28B also rotate about the axis of the input shaft portion 21a. As a result, one end (the lower end in the illustrated example) of the flat surface 29a on the inner diameter of the first bulging portion 28A presses the braking member 23A inward, and the other end (the upper end in the illustrated example) of the flat surface 29a on the inner diameter of the second bulging portion 28B presses the braking member 23B inward. As a result, the braking members 23A, 23B come relatively close to each other.

[0026] 1 and 2, the stationary member 24 is composed of a first frame 35 and a second frame 36. The first frame 35 is composed of a disk portion 35a and a short cylindrical peripheral wall portion 35b, with an axial hole 37 formed in the disk portion 35a, and the second frame 36 is disk-shaped and also has an axial hole 38 formed therein. A circumferential cutout portion 36a is formed at the outer end of the inner surface of the second frame 36, and the first frame 35 and the second frame 36 are integrated with each other in a state where the end of the peripheral wall portion 35b of the first frame 35 is fitted into this circumferential cutout portion 36a. Therefore, the stationary member 24 has an accommodation chamber S (see FIG. 2, etc.) formed therein in which the braking members 23, 23, the cam member 30, etc. are accommodated.

[0027] With the arm portion 22b of the output member 22 housed in the housing chamber S of the stationary member 24, the output shaft portion 22a is supported in the shaft hole 37 via a bearing 40, and with the main body portion 21b of the input member 21 housed in the housing chamber S, the input shaft portion 21a is supported in the shaft hole 38 via a bearing 41. Also, as shown in FIG. 2, the input shaft portion 21a of the input member 21 and the output shaft portion 22a of the output member 22 are arranged on the same axis.

[0028] The longitudinal outer end faces of the braking members 23A, 23B are formed as arcuate contact surfaces 42, 42, and the curvature of the contact surface 42 is smaller than the curvature of the inner diameter surface 43 of the peripheral wall portion 35b of the stationary member 24.

[0029] Next, the operation of the reverse input cutoff clutch configured as described above will be described. First, the case where torque is input to the input member 21 will be described. When torque is input to the input member 21, that is, when a rotational force in the direction of arrow A1 is applied as shown in FIG. 5, the braking members 23A and 23B move closer to each other in the radial direction, as described above. This movement causes the abutting surface 42 of the braking member 23 to move away from the abutted surface 43a of the stationary member 24. In this spaced-apart state, the input member 21 rotates around its axis (the axis of the input shaft portion 21a). This rotation causes the braking members 23, 23 to rotate. Furthermore, the cam member 30 sandwiched between the braking members 23, 23 rotates around the axis of the input member 21. When the cam member 30 rotates, the output member 22 connected to the cam member 30 rotates around the axis of the output shaft portion 22a. That is, when torque is input to the input member 21, the torque is transmitted to the output member 22, and the output shaft portion 22a of the output member 22 rotates.

[0030] For this reason, the present reverse input disconnecting clutch has a separation movement mechanism M1 that moves the first and second braking members 23A, 23B in a direction separating them from the stationary member 24, and the separation movement mechanism M1 can be configured by a pair of bulging portions 28A, 28B of the disk portion 27.

[0031] Furthermore, this reverse input cutoff clutch is provided with a transmission mechanism M2 that transmits torque input to the input member 21 to the output member 22 when the first and second braking members 23A, 23B are separated from the stationary member 24, and this transmission mechanism M2 can be composed of the first and second braking members 23A, 23B, a cam member 30, etc.

[0032] However, if torque is input in reverse to the output member 22, the torque is not transmitted to the input member 21. In other words, if torque is input (reverse input) to the output member 22, the output member 22 rotates. When the output member 22 rotates, the support shaft 31 connecting the cam member 30 and the output member 22 rotates around the axis of the output shaft 22a of the output member 22. Therefore, the cam member 30 rotates around the axis of the output shaft 22a of the output member 22, as shown in FIG. 7(a). Therefore, the cam member 30 presses each of the pair of braking members 23, 23 that are connected by the support shaft 34 so as to be rotatable relative to each other, toward the stationary member 24. In other words, as shown in FIGS. 6 and 7(a), the protrusion 30b interposed between the pair of braking members 23, 23 rotates around the axis O. The axis O is the axis of the input shaft portion 21a of the input member 21 and the axis of the output shaft portion 22b of the output member 22, which are coaxially aligned.

[0033] When the protrusion 30b rotates around the axis O, an edge X1 on the support shaft side of the side surface of the protrusion 30b facing the first braking member presses the first braking member 23A toward the stationary member 24, and an edge X2 on the anti-support shaft side of the side surface of the protrusion 30b facing the second braking member presses the second braking member 23B toward the stationary member 24. As a result, torque transmission is interrupted by a frictional force generated between the abutting surface 42 of the braking member 23 and the abutted surface 43a of the stationary member 24. Here, the midpoint position of the line segment connecting the edge X1 (first contact portion) and the edge X2 (second contact portion) is defined as an intermediate portion X3.

[0034] However, in order to block and stop the reverse input, regarding the relationship of the forces acting on one of the braking members 23 (in this case, the first braking member 23A), if the reverse input torque is T and the braking torque is T', then T < T' must hold. In this case, among the respective contact portions X1, X2 of the cam member 30 and the pair of braking members 23A, 23B, the distance from the contact portion X1 close to the rotation center O to the rotation center is r (see FIGS. 7(a) and 7(b)), the distance from the contact portion X2 far from the rotation center O to the rotation center is r', the distance from the rotation center O to the braking member 23 and the stationary member 24 is R, the friction coefficient of the contact portions X1, X2 of the cam member 30 and the braking member 23 is μ, and the friction coefficient of the contact portion C of the braking member 23 and the stationary member 24 is μ'. In this case, a tangential force Ft orthogonal to the straight line connecting the contact portion X1 and the rotation center O acts on the contact portion X1, and among the angles formed by the direction in which the tangential force Ft acts and the braking member pressed surface 23a, the acute angle side angle is β (see FIG. 7(b)). The braking member pressed surface 23a is the surface of the braking member 23 that faces the protrusion 30b of the cam member 30 and is pressed by the protrusion 30b. Let the angle formed by the tangent Y at the contact portion C between the braking member 23 and the stationary member 24 and the perpendicular line P passing through the rotation center O and orthogonal to the braking member pressed surface 23a be α. Therefore, in order to satisfy the above T < T', it is necessary to satisfy the formula shown in Equation 2 below.

Equation

[0035] Meanwhile, one of the brake members 23A, which comes into contact with the cam member 30 at X1, is pressed against the stationary member 24 by the cam member 30, and the brake member 23A comes to a standstill by satisfying the reverse input blocking condition of Equation 2. The other brake member 23B, which comes into contact with the cam member 30 at X2, which is farther from the support shaft 31 than X1, is pressed against the stationary member 24 by the cam member 30. However, since r' is large and does not satisfy the reverse input blocking condition of Equation 2, a rotational torque acts in the same direction as the reverse input torque acting on the output member 22, and this torque is transmitted to the support shaft 34. The cam member 30 presses the brake members 23A and 23B against the stationary member 24 between the brake members 23A and 23B, restricting the brake members 23A and 23B from moving toward each other. Therefore, the pair of brake members 23A and 23B are restricted from moving away from the stationary member 24. Furthermore, frictional force acts on braking member 23A in the direction opposite to the rotational direction of output member 22, causing it to rotate around support shaft 34 in a direction away from the other braking member 23B. This rotation increases the frictional force on the contact surface between stationary member 24 and braking member 23A, causing a self-amplifying increase in braking torque. Therefore, braking members 23A and 23B come to a standstill, restricting the rotation of cam member 30 and output member 22.

[0036] It is desirable to increase the distance between the contact portions of the cam member 30 and the pair of braking members 23A, 23B. Increasing the distance reduces the angle of rotation of the cam member 30 (specifically, the protrusion 30b of the cam member 30) sandwiched between the braking members 23A, 23B within the gap S1, thereby reducing backlash of the output member 22. Furthermore, the load acting on the cam member 30 is reduced, thereby increasing the strength of the clutch. It is also desirable to position the support shaft 31 connecting the cam member 30 and the output member 22 radially outward. Positioning the support shaft 31 radially outward reduces the rotation angle of the output member 22 at the position where the rotation of the cam member 30 is restricted, thereby reducing backlash of the output member 22. Furthermore, the load acting on the support shaft 31 is reduced, thereby increasing the strength of the clutch. In addition, in the prior art, the engagement portion of the output member and the contact portion of the pair of engaging members are symmetrical, and the length of r is limited because it significantly affects the strength and backlash of the output member. However, in the clutch according to the present invention, the distance between the contact portions X1 and X2 between the cam member 30 and the pair of braking members 23A and 23B can be increased even if r is reduced, so there is a high degree of freedom in designing r. Therefore, there is no need to increase R to satisfy the relationship in Equation 2, and the outer diameter size can be reduced.

[0037] As described above, according to the reverse input cutoff clutch of the present invention, when torque is input to the input member 21, the pair of braking members 23A, 23B separate from the stationary member 24. In this separated state, the torque input to the input member 21 is transmitted to the output member 22, causing the output member 22 to rotate. Furthermore, when torque is input to the output member 22, the cam member 30 rotates, causing the first and second braking members 23A, 23B to move relatively apart. This presses the first and second braking members 23A, 23B against the stationary member 24, thereby cutting off the transmission of torque from the output member 22 to the input member 21. The relative separation of the first and second braking members 23A, 23B is achieved by the rotation of the cam member 30 interposed between the first braking member 23A and the second braking member 23B. At this time, the cam member 30 restricts the first and second braking members 23A, 23B from approaching each other, effectively preventing the pair of braking members 23A, 23B from moving away from the stationary member 24. Furthermore, when the first and second braking members 23A, 23B move away from each other, the end of the cam member 30 on the first braking member side comes into contact with the first braking member 23A, and the end on the second braking member side comes into contact with the second braking member 23B, and if the end on the first braking member side rotates counterclockwise, the end on the second braking member side also rotates counterclockwise. In this case, the end on the first braking member side presses the side of the first braking member opposite the second braking member, and the end on the second braking member side presses the side of the second braking member opposite the first braking member. Incidentally, the distance between the first contact portion X1 on the cam member side that contacts the first braking member 23A and the second contact portion X2 on the cam member side that contacts the second braking member 23B can be set relatively long, and by setting it long, the angle of rotation of the cam member 30 between the first and second braking members 23A and 23B is reduced, thereby reducing backlash of the output member 22. Moreover, the load acting on the cam member 30 can be reduced, thereby increasing the strength of the clutch.

[0038] Therefore, in the present invention, it is possible to reduce backlash in the output member 22. Moreover, it is possible to reduce the load acting on the cam member 30, thereby increasing the strength of the clutch.

[0039] In the reverse input cutoff clutch shown in Fig. 1 etc., the braking members 23A, 23B are connected by a support shaft 34, but the reverse input cutoff clutch shown in Fig. 8 does not use a support shaft 34. The protrusions 33, 33 protruding inward from one longitudinal end of the main body 32, 32 of the braking member 23 are cylindrical protrusions 33A, 33B whose opposing surfaces are cylindrical.

[0040] In the reverse input cutoff clutch shown in FIG. 8, when torque is reversely input to the output member 22, the output member 22 rotates, as in the reverse input cutoff clutch shown in FIG. 1, etc., and the support shaft 31, which rotatably connects the output member 22 and the cam member 30, rotates (revolves). The rotation (revolution) of the support shaft 31 causes the cam member 30 to press each of the pair of braking members 23A, 23B toward the stationary member 24. The braking member 23A, which comes into contact with the cam member 30 at X1, is stationary because the relationship of reverse input torque T<braking torque T'. The braking member 23B, which has the relationship of reverse input torque T>braking torque T', rotates around the rotation axis O, and the cylindrical protrusions 33A, 33B of the braking member 23A come into contact with each other. A force acts on the cylindrical protrusion 33A of the braking member 23A in the same rotational direction as the output member 22. The cam member 30 presses the brake members 23A, 23B against the stationary member 24, restricting the movement of the brake members 23A, 23B toward each other. Therefore, the movement of the pair of brake members 23A, 23B away from the stationary member 24 is restricted. Furthermore, frictional force acts on the brake member 23A in the direction opposite to the rotational direction of the output member 22, causing the brake member 23A to rotate away from the brake member 23B around the contact points of the cylindrical protrusions 33A, 33B as a fulcrum. This rotation increases the frictional force at the contact surfaces between the stationary member 24 and the brake member 23A, resulting in a self-amplifying increase in braking torque. Therefore, the brake members 23A, 23B are stationary, restricting the rotation of the cam member 30 and the output member 22.

[0041] FIG. 10 shows the operation when torque is input to the input member 21. When torque is input to the input member 21, the input member 21 comes into contact with each of the pair of braking members 23A, 23B, pressing the pair of braking members 23 toward each other. The pair of braking members 23 come into contact with each other's cylindrical protrusions 33A, 33B, and rotate around the centers of the cylindrical protrusions 33A, 33B as fulcrums in a direction in which the braking members 23 approach each other. This rotation causes the braking members 23 to move away from the stationary member 24, and the pair of braking members 23 rotate with the cam member 30 sandwiched between them. The rotation of the cam member 30 rotates the output member 22, which is connected to the cam member 30 by the support shaft portion 31. Therefore, the input member 21 and the output member 22 rotate synchronously.

[0042] 1, and the reverse input cutoff clutch shown in FIG. 8 etc. has the same components as those shown in FIG. 1 etc., with the same reference numerals used to designate the same components, and their description will be omitted. Therefore, the reverse input cutoff clutch shown in FIG. 8 also achieves the same effects as the reverse input cutoff clutch shown in FIG. 1. Moreover, the reverse input cutoff clutch shown in FIG. 8 can reduce the number of parts compared to the reverse input cutoff clutch shown in FIG. 1, and can also form a load transmission path between the braking members by contact between the cylindrical protrusions, thereby improving strength.

[0043] In the reverse input disconnect clutch shown in FIG. 1, the first contact portion X1, which is interposed between a pair of braking members 23 and contacts one braking member 23A, and the second contact portion X2, which is contacts the other braking member 23B, are configured by a single protrusion 30b. That is, the edge X1 on the support shaft side of the side of protrusion 30b facing the first braking member is the first contact portion, and the edge X2 on the anti-support shaft side of the side of protrusion 30b facing the second braking member is the second contact portion. However, as shown in FIG. 11, they may be configured by two protrusions 30c and 30d. That is, the protrusion closer to the support shaft 31 is the first protrusion 30c, and the protrusion farther from the support shaft 31 is the second protrusion 30d, with the edge of protrusion 30c facing the first braking member being the first contact portion X1 and the edge of protrusion 30d facing the first braking member being the second contact portion X2.

[0044] 1, and the reverse input cutoff clutch shown in FIG. 11 has the same components as those shown in FIG. 1, etc., with the same reference numerals used to designate the same components. Therefore, the reverse input cutoff clutch shown in FIG. 11 achieves the same effects as the reverse input cutoff clutch shown in FIG. 1. Moreover, the one shown in FIG. 11 has the advantage that a space can be provided between the first protrusion 30c and the second protrusion 30d, making the volume smaller than that of the protrusion 30b shown in FIG. 1, and reducing the weight of the cam member 30.

[0045] Next, in the reverse input cut-off clutch shown in Figures 12 to 14, in the initial state, the support shaft portion 31 for connecting the output member 22 and the cam member 30 and the support shaft portion 34 for connecting the pair of braking members 23, 23 are arranged in opposite directions by 180° with respect to the rotation axis O.

[0046] 1, and the reverse input cutoff clutch shown in FIG. 12 is given the same reference numerals as the same components shown in FIG. 1, etc., and their description will be omitted. Therefore, the reverse input cutoff clutch shown in FIG. 12 achieves the same effects as the reverse input cutoff clutch shown in FIG. 1. Moreover, the distance from the support shaft portion 31 to the contact portion of the braking members 23, 23 can be shortened, which reduces the force acting on the contact portion of the cam member 30 and the braking member 23 and improves the strength of the reverse input cutoff clutch.

[0047] In the reverse input cut-off clutch shown in Figures 15 to 17, the braking members 23A, 23B are urged by the elastic member 50 in a direction in which they move relatively apart along the radial direction, and in a free state, the abutment surfaces 42, 42 of the braking members 23A, 23B abut against the abutted surface 43a of the inner diameter surface 43 of the peripheral wall portion 35b of the stationary member 24.

[0048] Specifically, the elastic member 50 is made of a coil spring, and recessed portions 51, 51 are provided on the corresponding surfaces 23A1, 23B1 of the braking members 23A, 23B that face each other, and the ends of the elastic member 50 fit into the recessed portions 51, 51. As a result, the elastic member 50 is elastically biased in a direction that moves it away from the braking members 23A, 23B.

[0049] With this configuration, it is possible to synchronize the attitudes of the braking members 23, 23 and stabilize the attitude of each braking member 23, thereby enabling accurate radial movement of each braking member 23. Furthermore, as will be described later, except when rotational torque is input to the input member 21, it is possible to keep the contact surface 42 of each braking member 23 pressed against the contacted surface 43a.

[0050] Although the above describes an embodiment of the present invention, the present invention is not limited to the above embodiment and various modifications are possible. For example, the contact portions X1 and X2 formed on the protrusion 30b (protrusions 30c and 30b) of the cam member 30 may be rounded or obtuse-angled. The dimensions r, r', and R, and the friction coefficients μ and μ' may be set arbitrarily as long as they satisfy the formula (2) described in the embodiment. The elastic member 50 may be a spring (such as a coil spring, leaf spring, or disc spring) made of metal or other material, a rubber material, or a resin material. The position of the elastic member 50 is not limited to the position shown in FIGS. 15 to 17, and may be any position capable of biasing the braking members 23A and 23B in a radially spaced apart direction. Furthermore, this reverse input cutoff clutch is symmetrical when viewed from both the input side and the output side, and when torque is input to the input member 21, the action is the same whether it is clockwise or counterclockwise, and when torque is input in reverse to the output member 22, the action is the same whether it is clockwise or counterclockwise. [Explanation of symbols]

[0051] 21 Input member 21a Input shaft 22 Output member 22a Output shaft 22b Arm part 23, 23A, 23B braking members 23a Braking member pressed surface 24 Stationary Members M1 Separation movement mechanism M2 transmission mechanism 30 Cam member 30a KARA main body part 30b protrusion (convex part) 30c convex part 30d convex part 31 Support shaft (connecting part) 33, 33A, 33B Protrusions 34 Support shaft M1 Distancing Movement Mechanism M2 Chuanda Agency O Rotation axis Contact parts (ends) of X, X1, and X2

Claims

1. A reverse input cutoff clutch having an input member to which torque is input, an output member to which torque is output, a first braking member and a second braking member capable of reciprocating in a radial direction, and a stationary member disposed radially outward of the first braking member and the second braking member, a separating movement mechanism that, when torque is input to the input member, moves the first braking member and the second braking member in a direction in which they approach each other in the radial direction, and moves the first braking member and the second braking member in a direction in which they move away from the stationary member; a transmission mechanism that transmits torque input to the input member to the output member in a state in which the first braking member and the second braking member are spaced apart from the stationary member, A reverse input cut-off clutch characterized in that a cam member is interposed between the first braking member and the second braking member, and when torque is reverse input to the output member, the rotational motion is transmitted to the cam member, causing the first braking member and the second braking member to move in a direction radially away from each other, and the first braking member and the second braking member are pressed against the stationary member, thereby cutting off the transmission of torque from the output member to the input member.

2. 2. The reverse input cutoff clutch according to claim 1, wherein the output member has an output shaft portion disposed coaxially with the axis of the input shaft portion of the input member, and an arm portion extending radially from the output shaft portion, and the cam member has a cam main body portion extending radially and having one radial end connected to a radially outer diameter side end of the arm portion of the output member, and a protrusion portion provided on the cam main body and disposed between the first braking member and the second braking member, and when torque is reverse input to the output member, the connecting portion of the arm portion swings around the output shaft portion of the output member, and the first contact portion and the second contact portion of the protrusion press against the braking member pressed surfaces of the first braking member and the second braking member, respectively, and move in directions radially apart from each other.

3. 3. The reverse input cutoff clutch according to claim 2, wherein an intermediate portion between the first contact portion and the second contact portion is disposed at a position radially spaced apart from the rotation center of the input shaft portion of the input member, and the first contact portion and the second contact portion of the cam member have a different distance to the rotation center of the input shaft portion of the input member.

4. 3. The reverse input cutoff clutch according to claim 2, wherein the first contact portion is disposed on the opposite side of the second contact portion with respect to a perpendicular line that passes through the rotation center of the cam member and is perpendicular to the pressed surface of the brake member.

5. 3. The reverse input cut-off clutch according to claim 2, wherein the first braking member and the second braking member swing about one radial end side, and the swing center is disposed on the opposite side of the intermediate portion of the first contact portion and the second contact portion with respect to a perpendicular line that passes through the rotation center of the input shaft and is perpendicular to the pressed surface of the braking member.

6. 3. The reverse input cutoff clutch according to claim 2, wherein a connecting portion between the arm portion of the output member and the cam member is disposed radially outward from a rotation center of the cam member.

7. 2. The reverse input cutoff clutch according to claim 1, wherein opposing protrusions are provided on one radial end of the first braking member and one radial end of the second braking member, the opposing surfaces of the protrusions are cylindrical, and when torque is input to the input member, the protrusions come into contact with each other, and the first braking member and the second braking member swing toward each other with the protrusion contact point as a fulcrum, and the first braking member and the second braking member move away from the stationary member.

8. 2. The reverse input cutoff clutch according to claim 1, wherein the first braking member and the second braking member are rotatable about a support shaft portion.

9. 3. The reverse input cutoff clutch according to claim 2, wherein the protrusion of the cam member is configured as a pair of convex portions spaced apart in the radial direction.

10. 2. The reverse input disconnect clutch according to claim 1, wherein the input member and the output member are rotatably supported relative to the stationary member.

Images