JP2019030137A - Motor with reverse input cutoff clutch and reverse input cutoff clutch - Google Patents

Abstract

To provide a low cost motor with a reverse input cutoff clutch capable of performing a positioning after being driven by a motor while saving energy, and a reverse input cutoff clutch connectable to the motor.SOLUTION: A reverse input cutoff clutch 30 comprises: an input side rotary member 32 connected to a drive shaft 26 of a motor 20; and an allowance mechanism for rotational torque transmission, provided between the input side rotary member 32 and an output shaft 31, which allows transmission of rotational torque to the output shaft 31 and inhibits a reverse input from the output shaft side to the input side rotary member 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor with a reverse input cutoff clutch and a reverse input cutoff clutch.

  Conventionally, in line parts where products such as packaging machines, box making machines and food production equipment flow, positioning devices that move these are used to position product guides, printing devices, various detectors, etc. Yes. In these positioning devices, the guide screw, the printing device, various detectors, and the like are moved and positioned to the required positions by manually driving the feed screw with the handle wheel.

  Conventionally, since manual positioning is performed, each time the position is changed according to the type of product of a different size, an operator uses a scaled sticker or a mechanical position indicator. The position to be positioned is determined.

  In order to reduce these manual operations, a guide screw, a printing device, various detectors, etc. are positioned by driving a feed screw with a motor that performs position control instead of a handle wheel that is manually operated. It is possible.

  Here, in the motor control capable of position control as proposed in Patent Document 1, it automatically operates at the start of operation and at the time when the positioning operation is completed, and the stop state of the drive shaft is maintained at the time of stop ( Servo lock is continued.

  In addition, after performing position control using the motor proposed in Patent Document 2, instead of servo lock, when the motor stops, it is operatively connected to the drive shaft, for example, by operating an electromagnetic brake. It is also possible to lock the output side.

JP 2011-109866 A JP 2011-50129 A

By the way, when the motor of Patent Document 1 is servo-locked, power is consumed by the motor even while the position is held, which is not preferable from the viewpoint of energy saving.
In addition, the electromagnetic brake of Patent Document 2 requires a control circuit for electromagnetically operating the electromagnetic brake in addition to the motor control, and there is a problem that costs increase.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motor with a reverse input cutoff clutch that can be energy-saving and positioned at a low cost after being driven by a motor, and a reverse input cutoff clutch that can be connected to the motor. There is.

  In order to solve the above-described problem, the motor with a reverse input cutoff clutch includes a motor, an input-side rotating member that is coupled to the drive shaft of the motor, and that inputs rotational torque of the motor, an output shaft, Rotation torque transmission allowance provided between the input side rotation member and the output shaft to allow transmission of the rotation torque to the output shaft and prevent reverse input from the output shaft side to the input side rotation member And a reverse input cutoff clutch having a mechanism.

  The outer peripheral surface of the output shaft includes at least a pair of engagement protrusions protruding in opposite directions from the shaft center, and the transmission member is engaged with the engagement protrusions to thereby cause the input side rotation member to be engaged. It is good also as what transmits this rotational torque to the said output shaft.

  The reverse input shut-off clutch of the present invention is connected to a drive shaft of a motor, and receives an input side rotating member that inputs rotational torque of the motor, an output shaft, and between the input side rotating member and the output shaft. A reverse input cut-off clutch provided with a rotation torque transmission permission mechanism which is provided and allows transmission of the rotational torque to the output shaft and prevents reverse input from the output shaft side to the input side rotation member; The rotational torque transmission permission mechanism includes an outer ring that covers and fixes the input-side rotating member and the output shaft, a transmission member that transmits the rotational torque of the input-side rotating member to the output shaft, and an inner ring of the outer ring. When the peripheral surface and the outer peripheral surface of the output shaft are engaged and disengaged and engaged, the output shaft is prevented from rotating and transmission of rotational torque from the output shaft to the input-side rotating member is interrupted. An engagement element; A biasing member that biases the engaging element in a direction to engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft, and the biasing force of the biasing member when the input-side rotating member rotates. Against this, it includes an engagement release member that releases the engagement of the engagement element with the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft.

  The rotational torque transmission permission mechanism includes an outer ring that covers and fixes the input-side rotating member and the output shaft, a transmission member that transmits the rotational torque of the input-side rotating member to the output shaft, and the outer ring When the inner peripheral surface and the outer peripheral surface of the output shaft can be freely engaged and disengaged, the output shaft is prevented from rotating, and transmission of rotational torque from the output shaft to the input side rotating member is interrupted. An engaging member, a biasing member that biases the engaging member in a direction to engage with an inner peripheral surface of the outer ring and an outer peripheral surface of the output shaft, and the engaging member when the input-side rotating member rotates. It is preferable that an engagement releasing member for releasing the engagement of the engaging element with the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft against the urging force of the urging member is included.

The transmission member may also serve as the engagement release member.
The outer peripheral surface of the output shaft includes at least a pair of engaging protrusions protruding in the radial direction from the shaft center, and the transmission member rotates the input-side rotating member by engaging with the engaging protrusions. Torque may be transmitted to the output shaft.

  According to the present invention, the positioning after being driven by the motor can be energy saving, and there is an effect that the cost is not increased.

(A) is a perspective view of a motor with a reverse input cutoff clutch of one embodiment, (b) is an exploded perspective view of a motor with a reverse input cutoff clutch. The perspective view of a reverse input interruption | blocking clutch. The longitudinal cross-sectional view of a reverse input interruption | blocking clutch. The disassembled perspective view of a reverse input interruption | blocking clutch. Explanatory drawing which shows the normal state of a reverse input interruption | blocking clutch. Explanatory drawing which shows a state when rotational torque is input into the input side rotation member of a reverse input interruption | blocking clutch. Explanatory drawing which shows a state when rotational torque is loaded to the output shaft of a reverse input interruption | blocking clutch.

Hereinafter, a motor with a reverse input cutoff clutch and a reverse input cutoff clutch according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1A, the motor 10 with a reverse input cutoff clutch includes a motor 20 and a reverse input cutoff clutch 30. The motor 20 is a geared motor and includes a motor body 22 and a speed reducer 24.

  The drive shaft 26 of the motor 20 (that is, the output shaft of the speed reducer 24) is connected to the input side rotation member 32 of the reverse input cutoff clutch 30 described later. The motor 20 is fixedly attached to a case or the like that is fixed to a base (not shown).

  The motor body 22 includes a rotary encoder 28. The rotary encoder 28 detects the rotation angle of the motor body 22 and outputs a detection signal (rotation angle) to a control circuit (not shown). The control circuit controls the position so as to eliminate the deviation between the current position calculated based on the detection signal and the target position designated in advance.

The control circuit stops the rotation drive of the motor body 22 when the deviation is eliminated and the target position is reached.
As shown in FIGS. 2, 3, and 4, the motor 10 with a reverse input cutoff clutch includes an output shaft 31, an input side rotating member 32, and an outer ring 33 that covers the output shaft 31 and the input side rotating member 32. .

  A small-diameter portion 34 and a large-diameter portion 35 are formed on the outer peripheral surface of the output shaft 31. As shown in FIGS. 5 to 7, in the output shaft 31, a pair of engaging protrusions 36 are provided on the outer peripheral surface of the end portion adjacent to the anti-small diameter portion side of the large diameter portion 35. Both engaging protrusions 36 protrude in the radial direction perpendicular to the axial direction, that is, protrude in opposite directions from the axial center.

As shown in FIG. 3, a mounting chamber 33a having an inner peripheral surface with a circular cross section and a storage chamber 33b having an inner peripheral surface with a circular cross section larger in diameter than the mounting chamber 33a are formed in the outer ring 33. .
As shown in FIG. 3, the output shaft 31 is rotatably supported via a bearing 37 with respect to the inner peripheral surface of the mounting chamber 33 a of the outer ring 33, and the small-diameter portion 34 protrudes from the outer ring 33 to the outside. Yes. The outer ring 33 is fixed to a base (not shown).

As shown in FIG. 3, the input side rotation member 32 is disposed in the storage chamber 33 b so as to face the end of the output shaft 31 on the side opposite to the small diameter portion.
The input side rotation member 32 is formed in a disc shape, and a shaft mounting hole 32a having a non-circular cross section is formed at the center thereof. The input-side rotation member 32 can be rotated integrally with the drive shaft 26 by the front end portion of the drive shaft 26 having a non-circular cross-section formed through the shaft mounting hole 32a so as not to be relatively rotatable. ing.

  As shown in FIG. 3, the drive shaft 26 penetrating the shaft mounting hole 32 a is inserted with play in a recess 31 a that is recessed in the end surface of the recess 31 a that faces the drive shaft 26. In addition, an oil-free bush 41 having an outward flange 42 is fitted into the recess 31 a, and the outward flange 42 is in contact with the input side rotation member 32.

  As shown in FIG. 3, in the storage chamber 33b, an oilless washer 38 having the same diameter as that of the storage chamber 33b is fitted on the motor side, and a C-shaped retaining ring 39 is a retaining ring on the inner peripheral surface of the storage chamber 33b. It is fitted in the fitting groove 33c. Since the retaining ring 39 is fitted in the retaining ring fitting groove 33c, the oilless washer 38 is prevented from being detached from the storage chamber 33b.

On the side surface of the input side rotating member 32 that faces the output shaft 31, two pairs of transmission pins 43 and 44 that project as a pair project in the axial direction.
The transmission pins 43 are positioned at positions opposite to each other by 180 ° with the central portion of the input side rotation member 32 as the center. As shown in FIG. They are arranged so as to be respectively engaged with the engaging protrusions 36 of the output shaft 31 at the time of normal rotation). That is, when the input side rotation member 32 is rotated forward by the motor 20, the transmission pin 43 is configured to transmit the rotational torque when the motor 20 is rotated forward to the output shaft 31.

  Further, the transmission pins 44 are positioned 180 ° opposite to each other with the central portion of the input side rotating member 32 as the center, and the input side rotating member 32 rotates counterclockwise as shown in FIG. They are arranged so as to be engaged with the engaging protrusions 36 of the output shaft 31 when they are rotated (hereinafter referred to as reverse rotation). In other words, when the input side rotation member 32 is reversely rotated by the motor 20, the transmission pin 43 transmits the rotational torque when the motor 20 is reversely rotated to the output shaft 31.

  As shown in FIGS. 4 and 5 to 7, in the output shaft 31, a wedge-shaped space is formed on the outer peripheral surface between the engagement protrusions 36 with the inner peripheral surface of the mounting chamber 33 a of the outer ring 33. A plurality of cam surfaces 45 are formed at equal intervals in the circumferential direction. The cam surface 45 includes a pair of inclined surfaces 46 and 47 that are inclined in opposite directions.

  The wedge-shaped space formed by the inclined surface 46 and the inner peripheral surface of the attachment chamber 33a is displaced from the wide portion to the narrow portion in the counterclockwise direction in FIGS. Further, the wedge-shaped space formed by the inclined surface 47 and the inner peripheral surface of the mounting chamber 33a is displaced from the wide portion to the narrow portion in the clockwise direction in FIGS.

  Engaging elements 48 and 49 are disposed between the inclined surfaces 46 and 47 of each cam surface 45 and the inner peripheral surface of the mounting chamber 33a. The engagement elements 48 and 49 are constituted by cylindrical rollers. The engagement elements 48 and 49 are disposed at positions that interfere with the movement trajectories of the transmission pins 44 and 43 when the input side rotation member 32 rotates.

  A coil spring 51 as an urging member is disposed between the engagement element 48 and the engagement element 49. The engagement element 48 and the engagement element 49 are urged toward the narrow portion of the wedge-shaped space by the coil spring 51, and when the motor 20 is stopped, the coil spring 51 causes the output from the inner peripheral surface of the mounting chamber 33a. Engagement with the inclined surface 46 of the shaft 31 prevents the engagement elements 48 and 49 from idling.

  When the motor 20 is stopped and the transmission pin 44 is separated from the engagement element 48, the separation distance between the transmission pin 44 and the engagement element 48 is the separation distance between the transmission pin 43 and the engagement protrusion 36. It is arranged to be shorter. With this arrangement, when the motor 20 rotates in the forward direction, the transmission pin 44 abuts on the engagement element 48 earlier than the transmission pin 43 abuts on the engagement protrusion 36, and the mounting chamber in the engagement element 48. The engagement between the inner peripheral surface of 33a and the inclined surface 46 of the output shaft 31 is released, and the engagement element 48 can be idled.

  Similarly, when the motor 20 is stopped and the transmission pin 43 is separated from the engagement element 49, the separation distance between the transmission pin 43 and the engagement element 48 is the separation distance between the transmission pin 44 and the engagement protrusion 36. It is arranged to be shorter than the distance. With this arrangement, when the motor 20 rotates in the reverse direction, the transmission pin 43 contacts the engaging element 49 earlier than the transmitting pin 44 contacts the engaging protrusion 36, and the mounting chamber 33 a in the engaging element 49. The engagement between the inner peripheral surface of the output shaft 31 and the inclined surface 47 of the output shaft 31 is released to allow the engagement element 49 to idle. In the present embodiment, the transmission pins 43 and 44 correspond to an engagement release member and are also used as a transmission member.

  In the present embodiment, the rotational torque transmission permission mechanism includes an outer ring 33, transmission pins 43 and 44 as engagement members and engagement release members, engagement elements 48 and 49, and a coil spring 51.

(Operation of the embodiment)
The operation of the motor with a reverse input cutoff clutch and the reverse input cutoff clutch configured as described above will be described.

  This motor 10 with a reverse input shut-off clutch is, for example, a motor 20 for positioning a product guide unit, a printing device, various detectors, etc. in a line part through which a product such as a packaging machine, a box making machine, or a food production apparatus flows. Is position controlled. A case where the motor 20 is rotated by this position control will be described.

  As shown by the arrow in FIG. 1B, when the motor 20 rotates in the forward direction, rotational torque is input to the input side rotating member 32, and the transmission pin 44 acts on the urging force of the coil spring 51 as shown in FIG. The engaging element 48 is pressed against the wide part of the wedge-shaped space. For this reason, the engagement between the inner peripheral surface of the attachment chamber 33 a and the inclined surface 46 of the output shaft 31 in the engagement element 48 is released. Thereafter, the transmission pin 43 presses the engagement protrusion 36, whereby the rotational torque of the input side rotation member 32 is transmitted to the output shaft 31, and the output shaft 31 is rotated forward. At this time, the engagement element 48 idles along the inner peripheral surface of the mounting chamber 33 a of the outer ring 33. Further, in this case, since the inclined surface 47 moves the engaging member 49 toward the wide portion of the wedge-shaped space when the output shaft 31 rotates forward, the engaging shaft 49 locks the output shaft 31. There is nothing.

  When the forward rotation of the motor 20 is stopped, the engaging member 48 is released from the pressing of the transmission pin 44, and therefore, the urging force of the coil spring 51 moves from the wide portion to the narrow portion of the wedge-shaped space, and the mounting chamber The output shaft 31 is locked by being engaged with the inner peripheral surface of 33 a and the inclined surface 46 of the output shaft 31. Further, the pressing of the transmission pin 43 against the engaging protrusion 36 is released. Therefore, since the output shaft 31 is locked, unlike the prior art, there is no need to hold the motor 20 that has stopped rotating in a servo lock or the like.

  As shown by the arrow in FIG. 1B, when the motor 20 rotates in the reverse direction, rotational torque is input to the input side rotation member 32, and the transmission pin 43 resists the biasing force of the coil spring 51. 49 is pressed toward the wide part of the wedge-shaped space. For this reason, the engagement between the inner peripheral surface of the attachment chamber 33 a and the inclined surface 47 of the output shaft 31 in the engagement element 49 is released. Thereafter, when the transmission pin 44 presses the engagement protrusion 36, the rotational torque of the input side rotation member 32 is transmitted to the output shaft 31 to reversely rotate the output shaft 31. At this time, the engaging element 49 idles along the inner peripheral surface of the mounting chamber 33 a of the outer ring 33. Further, in this case, since the inclined surface 46 moves the engaging member 48 toward the relatively wide portion of the wedge-shaped space by reversing the output shaft 31, the engaging shaft 48 locks the output shaft 31. There is no.

  When the reverse rotation of the motor 20 is stopped, the engaging member 49 is released from the pressing of the transmission pin 43, and therefore is moved by the biasing force of the coil spring 51 from the wide portion to the narrow portion of the wedge-shaped space, and the mounting chamber 33a. Is engaged with the inclined surface 47 of the output shaft 31 to lock the output shaft 31. Further, the pressure on the engaging projection 36 of the transmission pin 44 is released. Therefore, since the output shaft 31 is locked, unlike the prior art, there is no need to hold the motor 20 that has stopped rotating in a servo lock or the like.

  On the other hand, even if the rotational torque is reversely input to the output shaft 31, the engaging member 48 or the engaging member 49 depends on the rotation direction of the inner peripheral surface of the mounting chamber 33 a and the cam surface 45, that is, the wedge-shaped space. It is locked by engaging the narrow part.

  That is, even if the output shaft 31 tries to rotate in the clockwise direction of FIG. 7, the engaging member 48 engages with the inner peripheral surface of the mounting chamber 33a and the cam surface 45 (inclined surface 46), and the output shaft 31 is locked. Yes. This lock prevents the rotation torque from being transmitted from the output shaft 31 to the input side rotation member 32.

  Further, even if the output shaft 31 tries to rotate counterclockwise in FIG. 7, the engaging element 49 engages with the inner peripheral surface of the mounting chamber 33a and the cam surface 45 (inclined surface 47), and the output shaft 31 is locked. ing. This lock prevents the rotation torque from being transmitted from the output shaft 31 to the input side rotation member 32.

The present embodiment has the following features.
(1) In the motor with a reverse input cutoff clutch of this embodiment, the motor 20 is a motor whose position is controlled. The reverse input cutoff clutch 30 allows transmission of rotational torque to the output shaft 31 between the input-side rotating member 32 connected to the drive shaft 26 of the motor 20 and the input-side rotating member 32 and the output shaft 31, A rotation torque transmission allowing mechanism for preventing reverse input from the output shaft side to the input side rotation member 32;

  With this configuration, it is not necessary to hold the motor with a servo lock or the like, and power is not consumed by the motor even during a period in which the position is held, which is preferable from the viewpoint of energy saving. As a result, according to the present embodiment, the positioning after being driven by the motor can be energy saving, and there is an effect that the cost is not increased.

  (2) The rotational torque transmission allowing mechanism of the reverse input cutoff clutch of the present embodiment covers the input side rotating member 32 and the output shaft 31 and is fixedly arranged, and the rotational torque of the input side rotating member 32 is output shaft. Transmission pins 43 and 44 (transmission members) that transmit to 31 are provided. Further, the rotational torque transmission permission mechanism is detachable with respect to the inner peripheral surface of the outer ring 33 and the outer peripheral surface of the output shaft 31 and prevents the output shaft 31 from rotating when engaged. Engaging elements 48 and 49 are provided for interrupting transmission of rotational torque to the input side rotating member.

  The rotational torque transmission permission mechanism includes a coil spring 51 (biasing member) that biases the engaging elements 48 and 49 in a direction to engage with the inner peripheral surface of the outer ring 33 and the outer peripheral surface of the output shaft 31. In addition, the rotational torque transmission permission mechanism is configured so that the engagement members 48 and 49 resist the urging force of the coil spring 51 (the urging member) when the input-side rotation member 32 rotates, and the inner peripheral surface of the outer ring 33 of the engagement members 48 and 49. And engagement members 48 and 49 (engagement release members) for releasing the engagement with the outer peripheral surface of the output shaft 31.

As a result, according to the present embodiment, the upper (1) effect can be easily obtained by configuring the rotational torque transmission allowing mechanism as described above.
(3) In the present embodiment, the transmission pins 43 and 44 (transmission member) also serve as the engagement release member. As a result, according to the present embodiment, it is also possible to overlap the movement trajectories of the engagement member, the transmission member, and the engagement release member, shorten the radial dimension of the output shaft of the rotational torque transmission permission mechanism, Miniaturization is also possible. Further, according to this embodiment, since the transmission pin as the transmission member also serves as the disengagement member, the rotational torque transmission permission mechanism can be simplified, the number of parts can be reduced, and the cost can be reduced. Can do.

  (4) In the present embodiment, the outer peripheral surface of the output shaft 31 includes a pair of engaging protrusions 36 that protrude in the radial direction. Further, the transmission pins 43 and 44 (transmission members) are adapted to transmit the rotational torque of the input side rotation member 32 to the output shaft 31 by engaging with the engagement protrusions 36.

As a result, according to this embodiment, transmission of rotational torque can be easily realized by a simple configuration in which the transmission pin is engaged with the engagement protrusion.
In addition, this invention is not limited to the said embodiment, You may comprise as follows.

In the embodiment, the motor 20 is a geared motor, but is not limited to a geared motor, and may be a step motor, for example.
-In the said embodiment, the structure of a reverse input interruption | blocking clutch is not limited to the said embodiment, The reverse input interruption | blocking clutch of another structure may be sufficient.

In the above-described embodiment, the urging member is the coil spring 51. However, the urging member is not limited to the coil spring, and may be another elastic member such as a leaf spring or a bamboo spring.
-In above-mentioned embodiment, although the engagement protrusion 36 was made into a pair, you may comprise by three or more.

10: Motor with reverse input cutoff clutch,
20 ... motor, 22 ... motor body, 24 ... speed reducer,
26 ... Drive shaft, 28 ... Rotary encoder,
30 ... Reverse input cutoff clutch, 31 ... Output shaft, 31a ... Recess,
32 ... Input-side rotating member, 33 ... Outer ring, 33a ... Mounting chamber,
33b: storage chamber, 33c: retaining ring fitting groove,
34 ... small diameter part, 35 ... large diameter part, 36 ... engagement protrusion, 37 ... bearing,
38 ... Oil-free washer, 39 ... Retaining ring,
41 ... Oil-free bushing, 42 ... Flange,
43, 44 ... transmission pin (transmission member, disengagement member),
45 ... Cam surface, 46, 47 ... Inclined surface, 48, 49 ... Engagement element,
51 ... Coil spring (biasing member).

Claims (7)

A motor,
The output side of the rotational torque is connected to the drive shaft of the motor and provided between the input side rotational member for inputting the rotational torque of the motor, the output shaft, and the input side rotational member and the output shaft. A motor with a reverse input cut-off clutch including a reverse input cut-off clutch having a rotation torque transmission allowance mechanism that allows transmission to a shaft and blocks reverse input from the output shaft side to the input-side rotation member. The rotational torque transmission permission mechanism is
An outer ring that covers and fixes the input side rotation member and the output shaft;
A transmission member for transmitting the rotational torque of the input side rotation member to the output shaft;
When the outer ring is engaged with and disengaged from the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft, the output shaft is prevented from rotating, and the rotational torque from the output shaft to the input side rotating member is reduced. An engagement element for interrupting transmission;
A biasing member that biases the engaging element in a direction to engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft;
An engagement release member that releases the engagement of the engagement element with the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft against the urging force of the urging member when the input side rotation member rotates. The motor with a reverse input cutoff clutch according to claim 1 including:   The motor with a reverse input cutoff clutch according to claim 2, wherein the transmission member also serves as the disengagement member. The outer peripheral surface of the output shaft includes at least a pair of engagement protrusions protruding in the radial direction from the shaft center,
4. The motor with a reverse input cutoff clutch according to claim 3, wherein the transmission member transmits the rotational torque of the input side rotation member to the output shaft by engaging with the engagement protrusion. 5. An output-side rotation member connected to a drive shaft of the motor for inputting rotational torque of the motor, an output shaft, and the output shaft for the rotational torque provided between the input-side rotation member and the output shaft. A reverse input cut-off clutch having a rotational torque transmission permission mechanism that allows transmission to and prevents reverse input from the output shaft side to the input side rotation member,
The rotational torque transmission permission mechanism is
An outer ring that covers and fixes the input side rotation member and the output shaft;
A transmission member for transmitting the rotational torque of the input side rotation member to the output shaft;
When the outer ring is engaged with and disengaged from the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft, the output shaft is prevented from rotating, and the rotational torque from the output shaft to the input side rotating member is reduced. An engagement element for interrupting transmission;
A biasing member that biases the engaging element in a direction to engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft;
An engagement release member that releases the engagement of the engagement element with the inner peripheral surface of the outer ring and the outer peripheral surface of the output shaft against the urging force of the urging member when the input side rotation member rotates. And a reverse input cutoff clutch.   The reverse input cutoff clutch according to claim 5, wherein the transmission member also serves as the disengagement member. The outer peripheral surface of the output shaft includes at least a pair of engagement protrusions protruding in the radial direction from the shaft center,
The reverse input cutoff clutch according to claim 6, wherein the transmission member transmits a rotational torque of the input side rotation member to the output shaft by engaging with the engagement protrusion.