JP7188177B2 - reverse input cutoff clutch - Google Patents

Description

In the present invention, while the rotational torque input to the input member is transmitted to the output member, the rotational torque reversely input to the output member is completely blocked and not transmitted to the input member, or only a part of it is input. The present invention relates to a reverse input cut-off clutch having a function of transmitting to a member to cut off the remainder.

The reverse input cut-off clutch has 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. On the other hand, it has the function of completely blocking the rotational torque reversely input to the output member and not transmitting it to the input member, or transmitting only a part of it to the input member and blocking the rest. .

Reverse input cut-off clutches are roughly classified into a locking type and a free type, depending on the difference in the mechanism that cuts off the rotational torque that is reversely input to the output member. A lock-type reverse input cut-off clutch has a mechanism that prevents or suppresses rotation of an output member when rotational torque is reversely input to the output member. On the other hand, the free-type reverse input cut-off clutch has a mechanism that idles the output member when rotational torque is input to the output member. Which of the lock type reverse input cut-off clutch and the free type reverse input cut-off clutch is used is appropriately determined depending on the intended use of the device incorporating the reverse input cut-off clutch.

Japanese Patent Laying-Open Nos. 2002-174320, 2007-232095, and 2004-084918 disclose lock-type reverse input cutoff clutches. The reverse input cut-off clutch disclosed in Japanese Patent Application Laid-Open No. 2002-174320 utilizes the change in diameter caused by the torsion of the coil spring when rotational torque is reversely input to the output member, and is arranged inside the coil spring. A mechanism is provided to prevent rotation of the output member by tightening the member. On the other hand, the reverse input cut-off clutches disclosed in Japanese Patent Application Laid-Open Nos. 2007-232095 and 2004-084918 are designed to prevent the inner member and the outer member from rotating when rotational torque is reversely input to the output member. By moving the rolling elements arranged in the wedge-shaped space between the members to the narrower side of the wedge-shaped space in the radial direction and stretching them between the inner member and the outer member, the output It has a mechanism to prevent the member from rotating.

JP-A-2002-174320 JP-A-2007-232095 JP 2004-084918 A

The reverse input cut-off clutch disclosed in Japanese Patent Application Laid-Open No. 2002-174320 utilizes the change in diameter caused by the torsion of the coil spring, so it is necessary to secure a long axial dimension of the coil spring. Therefore, there is a problem that the axial dimension of the reverse input interrupting clutch becomes large. The reverse input cut-off clutches disclosed in Japanese Patent Application Laid-Open Nos. 2007-232095 and 2004-084918 use a large number of rolling elements, so there is a problem that the manufacturing cost increases. That is, generally, rolling elements are manufactured by cutting a metal wire rod to a predetermined length and then going through a plurality of processes such as forging (heading), rough grinding (flushing), heat treatment, fine grinding, and lapping. Therefore, the number of man-hours increases and the manufacturing cost increases. Therefore, the manufacturing cost of a reverse input cut-off clutch having a large number of rolling elements tends to increase.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a locking reverse input cutoff clutch that can be shortened in axial dimension and that can be manufactured at a reduced cost.

A reverse input interrupting clutch of the present invention includes an input member, an output member, a pressed member, and an engaging element.
The output member is arranged coaxially with the input member.
The pressed member has a pressed surface.
When rotational torque is input to the input member, the engaging element moves in a direction away from the surface to be pressed based on engagement with the input member, and engages with the output member to input input to the input member. When the rotational torque is reverse input to the output member, it moves in a direction approaching the surface to be pressed based on engagement with the output member, and the surface to be pressed. In other words, it is not transmitted to the input member, or part of the rotational torque reversely input to the output member is transferred to the input member and cut off the rest.
Particularly in the present invention, the engaging element has a laminated structure in which a plurality of engaging element base plates are laminated in the axial direction of the input member.
Further, in the present invention, an oil-retaining plate having a contour shape smaller than the contour shape of the engager element plate is sandwiched between the adjacent engager element plates.
This prevents the outer peripheral edge of the oil retaining plate from protruding from the outer peripheral surface of the engaging element.
Although it is out of the technical scope of the present invention, the oil impregnating plate may have the same contour shape as the engaging element base plate. Also in this case, the outer peripheral edge of the oil retaining plate can be prevented from protruding from the outer peripheral surface of the engaging element.

In the present invention, the plurality of engaging element base plates can be simply laminated and not connected to each other.
Alternatively, the plurality of engaging element base plates may be combined with each other.
When the plurality of engaging element base plates are to be connected to each other, they can be connected using fixing means such as adhesives, adhesive tapes, rivets, screws, and welding.

In the present invention, the engaging element base plate can be a press-formed metal plate.
Alternatively, the engaging element plate may be an injection molded product of synthetic resin.

As the oil-impregnated plate, for example, a base resin made of polyacetal, polyamide 6, polyamide 66, polyethylene, polybutylene terephthalate, etc., and lubricating oil uniformly dispersed in the base resin can be used. .

ADVANTAGE OF THE INVENTION According to this invention, the axial dimension of a reverse input interruption clutch can be shortened, and manufacturing cost can be held down.

FIG. 1 is a diagram showing a reverse input cutoff clutch of a first example of a reference example . FIG. 2 is a perspective view of a reverse input cutoff clutch of the first example of the reference example . FIG. 3 is a perspective view showing a portion of an input member taken out from the reverse input cut-off clutch of the first example of the reference example . FIG. 4 is a perspective view showing a part of an output member extracted from the reverse input cut-off clutch of the first example of the reference example . (A) of FIG. 5 is a perspective view showing an engaging element taken out from a reverse input interrupting clutch of the first example of the reference example , and (B) of FIG. is a perspective view showing the FIG. 6 is a diagram showing a state in which rotational torque is input to the input member with respect to the reverse input cut-off clutch of the first example of the reference example . FIG. 7 is a diagram showing a state in which rotational torque is reversely input to the output member with respect to the reverse input cutoff clutch of the first example of the reference example . FIG. 8 is a partially enlarged view of FIG. 6 showing the relationship of force acting on the engaging member from the output member when the rotational torque is reversely input to the output member. FIG. 9 is a diagram for explaining the conditions under which the output member is locked or semi-locked when the rotational torque is reversely input to the output member. FIG. 10 shows, with respect to the reverse input interrupting clutch of the first example of the reference example , the rotational torque is reversely input to the output member, the pressing surface of the engaging element contacts the pressed surface, and the input member side engaging portion is engaged. It is the elements on larger scale which show the state located in the width direction center part of the joint. FIG. 11 is a diagram corresponding to FIG. 5 showing a second example of the reference example . FIG. 12(A) is a front view of an engaging element incorporated in a reverse input cut-off clutch of a first example of the embodiment, and FIG. FIG. 4 is a corresponding schematic diagram;

[First example of reference example ]
A first example of the reference example will be described with reference to FIGS. 1 to 10. FIG. In the following description, axial direction, radial direction and circumferential direction refer to the axial direction, radial direction and circumferential direction of the reverse input cutoff clutch 1 unless otherwise specified. In this reference example, the axial direction, radial direction and circumferential direction of the reverse input cutoff clutch 1 coincide with the axial direction, radial direction and circumferential direction of the input member 2, and the axial direction, radial direction and circumferential direction of the output member 3. It coincides with the axial direction, radial direction and circumferential direction of the pressed member 4 .

[Description of the structure of the reverse input cutoff clutch]
A reverse input interrupting clutch 1 of this reference example is a locking type reverse input interrupting clutch, and includes an input member 2 , an output member 3 , a pressed member 4 , and a pair of engaging elements 5 . The reverse input cutoff clutch 1 transmits the rotational torque input to the input member 2 to the output member 3, while completely blocking the rotational torque reversely input to the output member 3 and transmitting it to the input member 2. Alternatively, it has a reverse input blocking function that transmits only a part of it to the input member 2 and blocks the rest.

The input member 2 is connected to an input-side mechanism such as an electric motor, and receives rotational torque. The input member 2 has an input shaft portion 6 and a pair of input member side engaging portions 7, as shown in FIG. The input shaft portion 6 has a stepped cylindrical shape, and its base end portion is connected to the output portion of the input side mechanism so as to be capable of transmitting torque, or is provided integrally with the output portion of the input side mechanism. . The pair of input member-side engaging portions 7 are substantially elliptical cylindrical, and are configured by projections extending axially from two positions on the distal end surface of the input shaft portion 6 on opposite sides in the diametrical direction. The pair of input member side engaging portions 7 are separated from each other in the diametrical direction of the input member 2 . For this reason, the pair of input member-side engaging portions 7 are arranged at portions of the tip surface of the input shaft portion 6 that are radially outwardly deviated from the center of rotation. The input member side engaging portion 7 has a radially outer surface having the same cylindrical contour shape as the outer peripheral surface of the tip portion of the input shaft portion 6, and a radially inner surface thereof extending in the circumferential direction. The central portion has an arc-shaped convex surface protruding radially inward.

The output member 3 is connected to an output-side mechanism such as a deceleration mechanism, and outputs rotational torque. The output member 3 is arranged coaxially with the input member 2, and has an output shaft portion 8 and an output member side engaging portion 9 as shown in FIG. The output shaft portion 8 has a cylindrical shape, and its tip portion is connected to the input portion of the output side mechanism so as to be capable of transmitting torque, or is provided integrally with the input portion of the output side mechanism. The output member side engaging portion 9 has a cam function. That is, the distance from the rotation center axis of the output member 3 to the outer peripheral surface of the output member side engaging portion 9 is not constant in the circumferential direction. In this reference example, the output member side engaging portion 9 has a substantially long columnar shape and extends axially from the central portion of the base end surface of the output shaft portion 8 . The outer peripheral side surface of the output member side engaging portion 9 is composed of a pair of mutually parallel flat surfaces and a pair of arcuate convex surfaces. Therefore, the distance from the center of rotation of the output member side engaging portion 9 to the outer peripheral side surface is not constant in the circumferential direction. The output member side engaging portion 9 is arranged between the pair of input member side engaging portions 7 .

As shown in FIG. 2, the pressed member 4 is formed in a thin annular shape, and is fixed to another member (not shown) such as a housing to restrict its rotation. The pressed member 4 is arranged coaxially with the input member 2 and the output member 3 and radially outside the input member 2 and the output member 3 . Specifically, a pair of the input member side engaging portion 7 and the output member side engaging portion 9 are arranged radially inside the pressed member 4 in the assembled state of the reverse input cutoff clutch 1 . The pressed member 4 has a pressed surface 10 which is a cylindrical concave surface on its inner peripheral surface.

The pair of engaging elements 5 are formed in a substantially semicircular plate shape and arranged radially inside the pressed member 4 . Each of the pair of engaging elements 5 has a pressing surface 11, which is a cylindrical convex surface, as a radially outer surface pressed against a pressed surface 10, and a radially inner surface as an engaging element side output engagement, which will be described later. The bottom surface 12 is flat except for the portion where the portion 15 is formed. Both sides of each engaging element 5 in the width direction are flat side surfaces 13 perpendicular to the bottom surface 12 . The radial direction with respect to the engaging element 5 means the direction perpendicular to the bottom surface 12 indicated by arrow A in FIG. 1, and the direction parallel to the bottom surface 12 indicated by arrow B in FIG. 5 is referred to as the width direction. The radius of curvature of the pressing surface 11 is less than or equal to the radius of curvature of the pressed surface 10 . The pressing surface 11 has a surface texture with a larger coefficient of friction than other portions of the engaging element 5 . The pressing surface 11 may be directly composed of the surface of the engaging element 5, or may be composed of a friction material fixed to the engaging element 5 by sticking, bonding, or the like.

In this reference example, the pressing surfaces 11 of the pair of engaging elements 5 are directed to the opposite side of the pressed member 4 in the radial direction, and the bottom surfaces 12 of the pair of engaging elements 5 are opposed to each other. Further, in a state in which the pair of engaging elements 5 are arranged radially inward of the pressed member 4, a gap is formed in at least one of the portion between the pressed surface 10 and the pressing surface 11 and the portion between the bottom surfaces 12. The inner diameter dimension of the pressed member 4 and the radial dimension of the engaging element 5 are regulated so as to exist.

The engaging element 5 has an engaging element side input engaging portion 14 and an engaging element side output engaging portion 15 . The engaging element-side input engaging portion 14 is configured by an input engaging hole that axially penetrates the radially intermediate portion of the engaging element 5 and is a rectangular elongated hole that is long in the width direction. The engaging element side input engaging portion 14 has a size that allows the input member side engaging portion 7 to be loosely inserted. Specifically, in a state in which the input member side engaging portion 7 is inserted inside the engaging member side input engaging portion 14, the input member side engaging portion 7 and the inner surface of the engaging member side input engaging portion 14 , there are gaps in the width direction of the engaging element 5 and in the direction orthogonal to the width direction. Therefore, the input member side engaging portion 7 can be displaced in the rotational direction of the input member 2 with respect to the engaging member side input engaging portion 14 (engaging member 5). , the input member-side engaging portion 7 can be displaced in a direction orthogonal to the width direction of the engaging element 5 .

The engaging element-side output engaging portion 15 is a substantially rectangular recess that is recessed radially outward from the widthwise central portion of the bottom surface 12 of each of the pair of engaging elements 5 . The engaging element side output engaging portion 15 has a size and a shape that allows the front half portion of the output member side engaging portion 9 in the short axis direction to be arranged without rattling. Specifically, the opening width of the engaging element-side output engaging portion 15 is substantially the same as (or slightly larger than) the dimension of the output member-side engaging portion 9 in the longitudinal direction. The radial depth is slightly smaller than 1/2 of the short axis direction dimension of the output member side engaging portion 9 . A bottom portion of the engaging piece side output engaging portion 15 is a flat surface parallel to the bottom surface 12 .

As shown in FIG. 5A, the engaging element 5 has a laminated structure in which a plurality of thin engaging element plates 16 are laminated in the axial direction. Each of the engaging element base plates 16 is a press-formed product made by punching a metal plate having a certain degree of rigidity such as a steel plate. Therefore, all the engaging element plates 16 forming the engaging element 5 have the same shape and the same plate thickness. As a material forming the engaging element base plate 16, for example, tool steel such as SK material and cold rolled steel plate such as SPCC or SPHC can be used. The plate thickness of the engaging element plate 16 can be appropriately determined depending on the material, the number of laminations, the usage conditions of the reverse input interrupting clutch 1, and the like, and is, for example, about 0.5 mm to 4 mm. However, the material, shape and plate thickness of the engaging element plate 16 do not necessarily have to be the same among all the engaging element plate 16 composing the engaging element 5 . Some of the engaging element plates 16 and the rest of the engaging element plates 16 can be made different in material, shape, or plate thickness.

The number of layers of the engaging element plate 16 can be appropriately determined according to the plate thickness and rigidity of the engaging element plate 16, the usage conditions of the reverse input interrupting clutch 1, and the like. can be done.

As shown in FIG. 5B, the engaging element base plate 16 has a pressing side 17 which is a convex arc-shaped outer peripheral edge forming the pressing surface 11 in an axially laminated state, and an axially laminated state. , and recesses 19 forming the engaging element-side output engaging section 15 in a state of being laminated in the axial direction. The pressing surface 11 can also be configured by fixing a friction material to the outer peripheral surface of the engaging element 5, which is a laminate formed by laminating a plurality of engaging element base plates 16, by pasting or bonding.

In this reference example, the engaging element 5 is configured in such a manner that a plurality of engaging element base plates 16 are simply laminated and are not connected to each other. For this reason, the side surfaces of the adjacent engaging element base plates 16 are directly overlapped without interposing other members. However, the plurality of engaging element base plates 16 can also be connected to each other. In this case, since it is possible to handle a plurality of engaging element plates 16 integrally, it is possible to improve the assembling workability of the reverse input interrupting clutch 1 and reduce the parts management cost. When connecting the engaging element base plates 16, fixing means such as adhesive, adhesive tape, rivets, screws, and welding can be used.

In the reverse input interrupting clutch 1 of this reference example, in its assembled state, the pair of input member side engaging portions 7 of the input member 2 arranged on one side in the axial direction The output member side engaging portion 9 of the output member 3 axially inserted into the side input engaging portion 14 and disposed on the other side in the axial direction is placed between the pair of engaging member side output engaging portions 15. It is inserted axially. That is, the pair of engaging elements 5 are arranged so that the output member side engaging portion 9 is sandwiched from the radially outer side by the engaging element side output engaging portions 15 . In this reference example, the axial dimension of the input member side engaging portion 7, the axial dimension of the output member side engaging portion 9, the axial dimension of the pressed member 4, and the axial dimension of the engaging element 5 are They are almost the same.

[Explanation of operation of reverse input cutoff clutch]
The operation of the reverse input cutoff clutch 1 of this reference example will be described.
(When rotational torque is input to the input member 2)
First, the case where a rotational torque is input to the input member 2 from the input side mechanism will be described.
When the rotational torque is input to the input member 2, as shown in FIG. rotate clockwise). Then, the radial inner surface of the input member side engaging portion 7 presses the inner surface of the engaging element side input engaging portion 14 radially inward, and the pair of engaging elements 5 are separated from the pressed surface 10 . move in each direction. That is, based on the engagement with the input member 2, the pair of engaging elements 5 are moved inward in the radial direction in which they approach each other (the engaging elements 5 located on the upper side in FIG. ) are moved upward). As a result, the bottom surfaces 12 of the pair of engaging elements 5 move toward each other, and the pair of engaging element-side output engaging portions 15 sandwich the output member-side engaging portions 9 of the output member 3 from both sides in the radial direction. . That is, while rotating the output member 3 so that the long axis direction of the output member side engaging portion 9 is parallel to the bottom surface 12 of the engaging element 5, the output member side engaging portion 9 and the pair of engaging element side output members are rotated. The engaging part 15 is engaged without backlash. Therefore, the rotational torque input to the input member 2 is transmitted to the output member 3 via the pair of engaging elements 5 and output from the output member 3 . In the reverse input cut-off clutch 1 of this reference example, when a rotational torque is input to the input member 2, regardless of the rotational direction of the input member 2, the pair of engagers 5 are moved away from the pressed surface 10. move. Rotational torque input to the input member 2 is transmitted to the output member 3 via the pair of engaging elements 5 regardless of the rotational direction of the input member 2 .

(When rotational torque is reversely input to the output member 3)
Next, the case where the rotational torque is reversely input to the output member 3 from the output side mechanism will be described.
When the rotational torque is reversely input to the output member 3, as shown in FIG. It rotates in the direction (clockwise in the example of FIG. 7). Then, the corner portion of the output member side engaging portion 9 presses the bottom surface of the engaging element side output engaging portion 15 radially outward, and the pair of engaging elements 5 move in a direction approaching the pressed surface 10. move each. That is, based on the engagement with the output member 3, the pair of engaging elements 5 are moved outward in the radial direction in which they are separated from each other (the engaging element 5 located on the upper side in FIG. ) are moved downward). Thereby, the pressing surface 11 of each of the pair of engaging elements 5 is pressed against the pressed surface 10 of the pressed member 4 . At this time, the pressing surface 11 and the pressed surface 10 come into contact with each other over the entire range or a part (for example, the central portion) of the pressing surface 11 in the circumferential direction. As a result, the rotational torque reversely input to the output member 3 is transmitted to the pressed member 4 fixed to another member (not shown) and is completely blocked and is not transmitted to the input member 2, or the torque is not transmitted to the output member 3. is transmitted to the input member 2 and the rest is cut off. In order to completely cut off the rotational torque reversely input to the output member 3 and prevent it from being transmitted to the input member 2, 1 The pair of engaging elements 5 are stretched between the output member side engaging portion 9 and the pressed member 4 to lock the output member 3 . On the other hand, in order to transmit only a part of the rotational torque reversely input to the output member 3 to the input member 2 and block the remaining part, the pressing surface 11 slides against the pressed surface 10. The pair of engaging elements 5 are stretched between the output member side engaging portion 9 and the pressed member 4 so as to move, and the output member 3 is semi-locked. That is, due to the sliding friction force generated when the pressing surface 11 slides against the pressed surface 10 , brake torque is applied to the output member 3 in the direction opposite to the reverse input rotational torque. Therefore, only a part of the rotational torque reversely input to the output member 3 is transmitted to the input member 3 via the engaging element 5 .

In this reference example, each of the pair of engaging elements 5 has a laminated structure of a plurality of engaging element base plates 16, and the plurality of engaging element base plates 16 are not coupled to each other. Based on the engagement with the joining portion 7 or the output member side engaging portion 9, all the engaging element base plates 16 constituting the engaging element 5 can move in the radial direction substantially synchronously.

In the reverse input cutoff clutch 1 of this reference example, the sizes of the gaps between the constituent members are adjusted so as to enable the above operation.

For example, in this reference example, as shown in FIG. When the joining portion 7 is positioned at the center in the width direction of the engaging member side input engaging portion 14, that is, the rotation center of the input member 2 (=the output member 3, the center of rotation of the input member 2 with respect to the moving direction of the pressing surface 11 relative to the pressed surface 10 (the vertical direction in FIG. 10). The radially inner surface of the input member-side engaging portion 7 and the inner surface of the engaging element-side input engaging portion 14 are made to be out of contact when the input member side engaging portion 7 and the engaging member side input engaging portion 14 are moved to the maximum distance in the radial direction outside (upper side in FIG. 10) from O. there is In other words, between the radial inner surface of the input member side engaging portion 7 and the inner surface of the engaging member side input engaging portion 14, the corner portion of the output member side engaging portion 9 is positioned as the engaging member side output engaging portion. There is a gap G that allows the pressing surface 11 to be pressed toward the pressed surface 10 based on pressing the bottom surface of 15 . As a result, when a rotational torque is reversely input to the output member 3, the movement of the engaging element 5 radially outward (upper side in FIG. 10) is prevented by the input member-side engaging portion 7. In addition, even after the pressing surface 11 contacts the pressed surface 10, the surface pressure acting on the contact portion between the pressing surface 11 and the pressed surface 10 is the magnitude of the rotational torque reversely input to the output member 3. , the output member 3 is properly locked or semi-locked.

The principle and conditions under which the output member 3 is locked or semi-locked when the rotational torque is reversely input to the output member 3 as described above will be described in more detail with reference to FIGS. 8 and 9. FIG.
When the corner of the output member-side engaging portion 9 comes into contact with the bottom surface of the engaging member-side output engaging portion 15 due to reverse input of rotational torque to the output member 3, as shown in FIG. A normal force Fc acts perpendicularly to the bottom surface of the output engaging portion 15 on the engaging element side at the contact portion X between the corner portion of the engaging portion 9 and the bottom surface of the output engaging portion 15 on the engaging element side. Further, the abutting portion X has a direction parallel to the bottom surface of the engaging member side output engaging portion 15, where μ is the coefficient of friction between the engaging portion 9 on the output member side and the output engaging portion 15 on the engaging member side. Frictional force μFc acts on . Here, assuming that the wedge angle between the direction of the line of action of the tangential force Ft acting on the contact portion X and the bottom surface of the engaging piece side output engaging portion 15 is θ, the tangential force Ft is expressed by the following equation (1 ).
Ft=Fc·sin θ+μFc·cos θ (1)
Therefore, the normal force Fc is expressed by the following equation (2) using the tangential force Ft.
Fc=Ft/(sin θ+μ·cos θ) (2)

The magnitude of the torque T transmitted from the output member 3 to the engaging element 5 when the corner portion of the output member side engaging portion 9 contacts the bottom surface of the engaging element side output engaging portion 15 is Assuming that the distance from the rotation center O to the contact portion X is r, the following equation (3) is obtained.
T=r·Ft (3)

As described above, since the normal force Fc acts on the contact portion X, as shown in FIG. It is pressed by a force of force Fc. Therefore, the coefficient of friction between the pressing surface 11 and the pressed surface 10 is defined as μ′, and the distance from the rotation center O of the output member 3 to the contact portion Y between the pressing surface 11 and the pressed surface 10 is defined as R. Then, the magnitude of the brake torque T' acting on the engaging element 5 is expressed by the following equation (4).
T'=μ'RFc (4)
Therefore, it can be seen that the coefficient of friction μ', the distance R, and the normal force Fc should be increased in order to obtain a greater braking force.

Further, in order to lock the output member 3 and prevent the rotational torque reversely input to the output member 3 from being transmitted to the input member 2, the transmission torque T and the brake torque T' must be the following (5): It is necessary to satisfy the relationship of the formula.
T<T' (5)
Further, the following equation (6) is obtained by substituting the above equations (1) to (4) into the above equation (5).
μ′R/(sin θ+μ·cos θ)>r (6)
From the above formula (6), it can be seen that the output member 3 can be locked even if the distance R is reduced by increasing the coefficient of friction μ′ between the pressing surface 11 and the pressed surface 10 .

Further, assuming that the friction coefficient μ and the friction coefficient μ′ are 0.1, the following equation (7) is obtained from the above equation (6).
R>10r(sin θ+0.1 cos θ) (7)
From the above equation (7), the distance r from the rotation center O of the output member 3 to the contact portion X, the distance R from the rotation center O of the output member 3 to the contact portion Y, and the line of action of the tangential force Ft and the wedge angle .theta.

On the other hand, in order for the output member 3 to be semi-locked so that only a part of the rotational torque reversely input to the output member 3 is transmitted to the input member 2 and the rest is cut off, the transmission torque T and and the brake torque T' must satisfy the relationship of the following expression (8).
T>T' (8)
Further, as is clear from the above equation (6), the friction coefficient μ between the output member side engaging portion 9 and the engaging member side output engaging portion 15, the friction between the pressing surface 11 and the pressed surface 10 coefficient μ′, distance r from the rotation center O to the contact portion X, distance R from the rotation center O to the contact portion Y, the direction of the line of action of the tangential force Ft and the bottom surface of the engaging piece side output engagement portion 15 By appropriately setting the wedge angle θ between , the output member 3 can be semi-locked.

Further, when rotational torque is input to the input member 2 while the output member 3 is locked or semi-locked, the normal force acting on the engaging element 5 from the input member 2 acts on the engaging element 5 from the output member 3. The output member 3 is unlocked or semi-locked when it becomes larger than the normal force Fc. In other words, the engaging element 5 moves radially inward, and rotational torque is transmitted from the input member 2 to the output member 3 .

According to the reverse input cut-off clutch 1 of this reference example having the above configuration and operating as described above, the axial dimension can be shortened, and the manufacturing cost can be suppressed.
The reverse input cut-off clutch 1 of this reference example converts at least part of the rotation of each of the input member 2 and the output member 3 into radial movement of the engager 5 . By converting the rotation of the input member 2 and the output member 3 into radial movement of the engaging element 5 in this way, the engaging element 5 is engaged with the output member 3 positioned radially inside the engaging element 5. Alternatively, the engaging element 5 is pressed against the pressed member 4 located radially outside the engaging element 5 . In this way, the reverse input cut-off clutch 1 of this reference example transfers rotational torque from the input member 2 to the output member 3 based on the radial movement of the engaging element 5 controlled by the rotation of each of the input member 2 and the output member 3. can be switched between the locked or semi-unlocked state of the output member 3 in which the power can be transmitted and the locked or semi-locked state of the output member 3 in which the rotation of the output member 3 is prevented or suppressed. The axial dimension of the entire device can be shortened.

Moreover, the engaging element 5 has both the function of transmitting the rotational torque input to the input member 2 to the output member 3 and the function of locking or semi-locking the output member 3 . Therefore, the number of parts of the reverse input interrupting clutch 1 can be reduced, and the operation is stabilized compared to the case where separate members have the function of transmitting the rotational torque and the function of locking or semi-locking. be able to. For example, when the function of transmitting rotational torque and the function of locking or semi-locking are provided to different members, there is a possibility that the timing of locking or semi-unlocking and the timing of starting transmission of rotational torque will be off. In this case, if the rotational torque is reversely input to the output member during the period from locking or semi-unlocking to the start of transmission of rotational torque, the output member will be locked or semi-locked again. In this reference example, the engaging element 5 is provided with both a function of transmitting rotational torque to the output member 3 and a function of locking or semi-locking the output member 3, which causes such inconvenience. can be prevented.

In addition, since the direction of the force acting on the engaging element 5 from the input member 2 is opposite to the direction of the force acting on the engaging element 5 from the output member 3, the magnitude relationship of both forces can be regulated. , the moving direction of the engaging element 5 can be controlled. Therefore, the switching operation between the locked or semi-locked state and the locked or semi-unlocked state of the output member 3 can be performed stably and reliably. Therefore, like the conventional reverse input cutoff clutches described in Japanese Patent Laid-Open No. 2007-232095 and Japanese Patent Laid-Open No. 2004-084918, the rolling elements engage with the narrow portion of the wedge-shaped space in the radial direction. It is possible to prevent the inconvenience that the lock cannot be released due to the lock remaining stuck.

In addition, since the engaging element 5 is configured by laminating a plurality of engaging element base plates 16 in the axial direction, each engaging element base plate 16 is punched out from a metal plate such as a steel plate. It can be created only by giving. For this reason, when using rolling elements that must be manufactured through a plurality of processes, such as the conventional reverse input cutoff clutches described in Japanese Patent Laid-Open No. 2007-232095 and Japanese Patent Laid-Open No. 2004-084918, In comparison, manufacturing costs can be suppressed. Furthermore, when the engaging element 5 is integrally manufactured without using a laminated structure as in this reference example, it can be manufactured by casting, powder metallurgy, cutting, or the like. Since punching by press working does not require man-hours compared to the method, the manufacturing cost can be sufficiently suppressed even when compared to the case where the engaging element 5 is integrally manufactured.

Furthermore, the number of layers of the engaging element plate 16 can be changed according to the usage conditions of the reverse input interrupting clutch 1 . Therefore, it is possible to easily adjust the surface pressure between the pressed surface 10 and the pressing surface 11 . Note that the outer peripheral surface can be polished while the engaging element plates 16 are stacked. However, since the outer peripheral edge of the engaging element plate 16 is worn with use even if the polishing process is not performed, the outer peripheral edge of all the engaging element plate 16 must be polished in the same way as when the polishing process is applied. the shape will be the same.

[Second example of reference example ]
A second example of the reference example will be described with reference to FIG.
In this reference example, pressing surfaces 11a to be pressed against a pressed surface 10 (see FIG. 1) are provided at two circumferentially spaced positions on the radial outer surface of the engaging element 5a. Each pressing surface 11 a is a cylindrical convex surface having a radius of curvature smaller than the radius of curvature of the pressed surface 10 . Between the pair of pressing surfaces 11a located in the circumferentially intermediate portion of the radially outer side surface of the engaging element 5a, the pressing surfaces 11a are not pressed against the pressed surface 10 (there is always a gap between them and the pressed surface 10). (existing) flat non-contact surface 20 is provided. Therefore, the width dimension of the engaging piece 5a in the radial direction is smaller than that of the engaging piece 5 of the first example of the embodiment. Further, while the contour shape of the radially outer surface of the engaging piece 5 of the first example of the reference example was a circular arc as a whole, the contour shape of the radially outer surface of the engaging piece 5a of the present reference example was as follows: It is configured by connecting the ends of a pair of circular arc portions with a straight portion.

The engaging element 5a has an engaging element-side input engaging portion 14a, which is a substantially arc-shaped elongated hole, in a radially intermediate portion. The input member side engaging portion 7 of the input member 2 (see FIG. 3) is provided inside the engaging member side input engaging portion 14a so as to be capable of moving farther and nearer with respect to the pressed surface 10, and the input member 2 are loosely engaged to allow movement in the rotational direction of the

The engaging element 5a as described above has a laminated structure in which a plurality of engaging element base plates 16a are laminated in the axial direction. The engaging element base plate 16a has pressing sides 17a at two circumferentially spaced positions on the radial outer surface thereof, the pressing sides 17a forming the pressing surface 11a when laminated in the axial direction. , there is a linear portion 21 that constitutes the non-contact surface 20 in a state of being laminated in the axial direction.

In the reverse input interrupting clutch provided with the engaging elements 5a as described above, when the rotational torque is reversely input to the output member 3 (see FIG. 4), the pair of the engaging elements 5a provided on the radially outer surfaces of the engaging elements 5a The pressing surface 11 a is pressed against the pressed surface 10 . Since the radius of curvature of the pressing surface 11a is smaller than the radius of curvature of the pressed surface 10, a wedge effect can be obtained, and a larger normal force (brake torque) can be obtained than in the first example of the reference example . can.
Other configurations and effects are the same as those of the first reference example .

[ First example of embodiment]
A first example of the embodiment will be described with reference to FIG. 12 .
In this example, an oil-retaining plate 22 is sandwiched between the axially adjacent engaging element base plates 16 constituting the engaging element 5b. The oil-impregnated plate 22 is made of, for example, polyacetal, polyamide 6, polyamide 66, polyethylene, polybutylene terephthalate, or the like as a base resin, and lubricating oil is uniformly dispersed inside the base resin.

The oil retaining plate 22 has a contour shape smaller than the contour shape of the engaging element base plate 16 . In addition, the oil retaining plate 22 has a through hole 23 in a radially intermediate portion through which the input member side engaging portion 7 of the input member 2 (see FIG. 3) can be loosely inserted.

In this example, the lubricant contained in the oil retaining plate 22 is applied to the contact portion between the pressed surface 10 and the pressing surface 11, the output member side engaging portion 9 (see FIG. 1) and the engaging member side output engaging portion 15. and the engaging portion between the input member-side engaging portion 7 and the engaging member-side input engaging portion 14 can be supplied efficiently over a long period of time. As a result, the wear of each part constituting the reverse input interrupting clutch 1 can be suppressed, and the durability of the reverse input interrupting clutch 1 can be improved. In addition, since the oil impregnating plate 22 has a contour shape smaller than the contour shape of the engaging element base plate 16, the outer peripheral edge of the oil impregnating plate 22 should not protrude from the outer peripheral surface of the engaging element 5. can do. Therefore, the provision of the oil retaining plate 22 adversely affects the contact state between the pressed surface 10 and the pressing surface 11 and the engagement state between the output member side engaging portion 9 and the engaging member side output engaging portion 15. You can prevent giving.
Other configurations and effects are the same as those of the first reference example .

The structures of the first example of the embodiment and each example of the reference example described above can be combined as appropriate and implemented as long as there is no contradiction.

In the reverse input interrupting clutch of the present invention, the number of engaging elements provided in various machines is not limited to two as shown in the first example of the embodiment and the reference example, and may be one or three or more. It is good as Also, the engagement structure between the input member and the output member and the engaging member is not limited to the structures shown in the first example and the reference example of the embodiment. As long as the rotation of each of the input member and the output member can be converted into the radial movement of the engager, various conventionally known structures can be adopted.

A worm gear reducer with a self-locking function is used in an electric power window of an automobile, which is a type of lifting device, but a reverse input cutoff clutch can be provided instead of the self-locking function. If the worm reducer has a self-locking function, the positive efficiency will decrease and the size of the device may increase. can be prevented.

1 reverse input interrupting clutch 2 input member 3 output member 4 pressed member 5, 5a, 5b engaging element 6 input shaft portion 7 input member side engaging portion 8 output shaft portion 9 output member side engaging portion 10 pressed surface 11 , 11a pressing surface 12 bottom surface 13 side surface 14 , 14a engaging element side input engaging portion 15 engaging element side output engaging portion 16, 16a engaging element base plate 17, 17a pressing side 18 through hole 19 concave portion 20 non-contact surface 21 straight portion 22 Oil-impregnated plate 23 Through hole

Claims (5)

an input member;
an output member coaxially arranged with the input member;
a pressed member having a pressed surface;
When a rotational torque is input to the input member, the rotational torque input to the input member moves away from the pressed surface based on engagement with the input member and engages with the output member. When the torque is transmitted to the output member and the rotational torque is reversely input to the output member, it moves toward the surface to be pressed based on the engagement with the output member and contacts the surface to be pressed. By doing so, an engaging element that completely cuts off the rotational torque reversely input to the output member or transmits a part of the rotational torque reversely input to the output member to the input member and cuts off the rest. prepared,
The engaging element has a laminated structure in which a plurality of engaging element base plates are laminated in the axial direction of the input member,
An oil-retaining plate having a contour shape smaller than the contour shape of the engaging element base plate is sandwiched between the adjacent engaging element base plates.
Reverse input cut-off clutch. 2. The reverse input interrupting clutch according to claim 1, wherein said plurality of engaging element plates are not coupled with each other. 2. The reverse input interrupting clutch according to claim 1, wherein said plurality of engaging element plates are coupled with each other. The reverse input interrupting clutch according to any one of claims 1 to 3, wherein the engaging element base plate is a press-formed metal plate. The reverse input interrupting clutch according to any one of claims 1 to 4, wherein the oil impregnated plate is a base resin in which lubricating oil is dispersed.

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