WO2017145934A1

WO2017145934A1 - Control method for reverse input prevention clutch

Info

Publication number: WO2017145934A1
Application number: PCT/JP2017/005912
Authority: WO
Inventors: 幸宏西尾; 寛哲徳永
Original assignee: Ntn株式会社
Priority date: 2016-02-23
Filing date: 2017-02-17
Publication date: 2017-08-31
Also published as: JP2017150530A

Abstract

In the present invention, during rotary positioning of an output-side member, from the start of energization of a motor that applies input torque to a reverse input prevention clutch to the end of positioning, an electromagnetic clutch of a lock release retaining means is energized and an unlocked state is retained so that, during the rotary positioning operation, even if reverse input torque is applied at the same time and in the same direction as input torque, the transmission of rotation can be accomplished smoothly without an output shaft relocking. When rotary positioning has been completed, energization of the motor is interrupted after energization of the electromagnetic clutch is interrupted and a locked state is restored, and as a result, the rotary position of the output-side member is not altered by reverse input torque.

Description

Control method of reverse input prevention clutch

The present invention relates to a control method for a reverse input preventing clutch that transmits rotation on the input side to the output side when input torque is applied and prevents the input side from rotating in response to reverse input torque.

The reverse input prevention clutch transmits the rotation to the output side when input torque is applied to the input side, and prevents the input side from rotating when reverse input torque is applied to the output side. . There is a type of the reverse input prevention clutch that locks the output side with respect to the reverse input torque (hereinafter, this method is referred to as “lock type”) (for example, refer to Patent Document 1 below).

The lock-type reverse input prevention clutch described in Patent Document 1 transmits the rotation of the input shaft to the output shaft with a slight angular delay between the input shaft and the output shaft that rotate about the same axis. Torque transmission means is provided, the outer ring whose rotation is restricted is arranged on the radially outer side of the output shaft, a plurality of cam surfaces are provided on the outer peripheral surface of the output shaft, and the inner peripheral cylindrical surface of the outer ring and each cam surface of the output shaft A wedge-shaped space gradually narrowing on both sides in the circumferential direction is formed, and a pair of rollers and a spring for pushing the roller into the narrow portion of the wedge-shaped space are incorporated in each wedge-shaped space, and both circumferential sides of each wedge-shaped space ( A column portion of a cage that rotates integrally with the input shaft is inserted at a position facing the spring in the circumferential direction across the roller.

In this reverse input prevention clutch, each roller is pushed into the narrow part of the wedge-shaped space by the elasticity of the spring, so even if reverse input torque is applied to the output shaft, the roller on the rear side in the rotational direction is applied to the outer ring and the output shaft. Engagement locks the output shaft and prevents rotation from the output shaft to the input shaft.

On the other hand, when an input torque is applied to the input shaft, the column of the cage pushes the roller on the rear side in the rotational direction against the elastic force of the spring to the wide part of the wedge-shaped space, so that the roller, outer ring and output After the engagement with the shaft is released and the output shaft is released from the locked state, rotation is transmitted from the input shaft to the output shaft by the torque transmitting means (at this time, the roller on the front side in the rotation direction is wedge-shaped space). ) So that it does not engage with the outer ring and the output shaft.

Such a lock-type reverse input prevention clutch is, for example, an output-side member that inputs rotational torque to an input shaft by a motor drive and outputs rotational torque from an output shaft as described in Patent Document 2 below. It may be incorporated in a rotational positioning device that positions the rotational position.

JP 2004-176679 A JP 2003-56596 A

However, in the above-described lock type reverse input prevention clutch, when the input torque and the reverse input torque are applied in the same direction at the same time, the roller on the rear side in the rotation direction is pushed by the pillar portion of the cage by the input torque and is wedge-shaped. When moving to the vast part of the space, the output shaft released from the locked state rotates at the rotational speed exceeding the rotational speed of the input shaft by reverse input torque (idle), and the roller relatively moves to the narrow part of the wedge-shaped space. When the output shaft returns, the output shaft is locked again, and immediately after that, the operation of releasing the locked state by the rotation of the input shaft is repeated to generate vibration, and the output shaft may not rotate smoothly. Moreover, when the vibration continues, the spring pressing the roller may be broken. For this reason, for example, in a rotation positioning device incorporating this reverse input prevention clutch, the rotation positioning operation of the output side member may not be performed efficiently.

In view of this, the present invention is capable of smoothly transmitting rotation even when input torque and reverse input torque are applied in the same direction at the same time when a lock-type reverse input prevention clutch is incorporated in a rotational positioning device, and efficient rotational positioning operation. It is an issue to be able to perform.

In order to solve the above problems, the present invention provides an input shaft to which rotational torque is input from a drive actuator of a rotational positioning device, and outputs rotational torque to an output side member that is arranged coaxially with the input shaft and is rotationally positioned. Output shaft, an outer ring disposed radially outside the output shaft in a state where rotation is constrained, and provided between the outer ring and the output shaft, and outputs a reverse input torque applied to the output shaft. A lock means for locking the shaft and the outer ring; a lock release means provided on the input shaft for releasing the lock state by the lock means for an input torque applied to the input shaft; and the lock state by the lock means is released. A torque transmitting means for transmitting an input torque applied to the input shaft to the output shaft, and a state in which the locked state by the locking means is released. In the control method of the reverse input preventing clutch provided with the lock release holding means, the lock means is provided with a cylindrical surface on the inner periphery of the outer ring and a plurality of cam surfaces on the outer periphery of the output shaft, A wedge-shaped space that is gradually narrowed on both sides in the circumferential direction is formed between the inner peripheral cylindrical surface of the outer ring and each cam surface of the output shaft. A pair of engagement elements and a pair of engagement elements are formed in each of these wedge-shaped spaces. And an elastic member that pushes each engagement element into a narrow portion of the wedge-shaped space.The lock release means is integrated with the input shaft when input torque is applied to the input shaft. Rotating and pushing out the engagement member on the rear side in the rotation direction of the pair of engagement elements to the wide part of the wedge-shaped space, and the unlocking holding means is an unlocking member driven by a control actuator, The pair of Each of the couplings is pushed out to the wide part of the wedge-shaped space and engaged with the output shaft so as to rotate integrally with the output shaft. The drive actuator is energized to start rotational positioning of the output side member, and at the same time, the control actuator To unlock the output side member until the rotation positioning of the output side member is completed.When the rotation positioning of the output side member is completed, the control actuator is energized. A configuration is adopted in which the power supply to the drive actuator is cut off after the cut-off.

In other words, when performing rotational positioning of the output side member, reverse input torque is input during rotational positioning operation by energizing the control actuator from the start of energization to the drive actuator to the completion of rotational positioning to maintain the unlocked state. Even if the torque is applied in the same direction as the torque, the output shaft rotates smoothly without re-locking. Thus, the rotation position of the output side member is prevented from being changed by the reverse input torque.

When the control actuator is an electromagnetic clutch, the electromagnetic clutch is energized by lowering the electric power while holding the unlocked state relative to the electric power from the start of energization to the completion of unlocking. It is good to reduce power consumption inside. This is because the electromagnetic clutch requires the largest amount of power when starting up.

As described above, the present invention provides a method for controlling a lock-type reverse input prevention clutch incorporated in a rotary positioning device. Even if the input torque and the reverse input torque are simultaneously applied in the same direction during the rotary positioning operation, Since the release state is maintained and the output shaft is not re-locked, smooth rotation transmission is possible, and when the rotation positioning is completed, the drive actuator is de-energized after returning to the locked state. Since it did in this way, the rotation position of an output side member does not change with reverse input torque, but a rotation positioning operation can be performed efficiently.

Vertical front view of a reverse input prevention clutch to which the control method of the embodiment is applied Sectional view along line II-II in Fig. 1 (excluding housing) Sectional view along line III-III in Fig. 1 (excluding housing) 1 is a cross-sectional view of the main part of FIG. Sectional drawing explaining unlock release holding | maintenance operation | movement corresponding to FIG. 4A 2 is an enlarged cross-sectional view of the main part of FIG. Sectional drawing explaining unlock release holding | maintenance operation | movement corresponding to FIG. 5A Time chart showing the control method of the reverse input prevention clutch of the embodiment The time chart which shows the energization control method of the electromagnetic clutch in the control method of FIG. The time chart which shows the energization control method of the electromagnetic clutch in the control method of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a lock-type reverse input prevention clutch incorporated in a rotary positioning device and to which a control method of an embodiment is applied. The reverse input prevention clutch includes an input shaft 1, an output shaft 2 arranged coaxially with the input shaft 1, an outer ring 3 arranged on the radially outer side of the large diameter portion of the output shaft 2, and the output shaft 2 and the outer ring. 3, a housing 4 disposed on the outer side in the radial direction, and an input side cage 5, a rotary cage 6 having a plurality of

pillars

5 a, 6 a, 7 a inserted between the output shaft 2 and the outer ring 3, control A cage (unlock member) 7, an engagement piece 8 provided on the outer periphery of the position adjacent to the large diameter portion of the output shaft 2, and a roller (engagement member) 9 incorporated between the output shaft 2 and the outer ring 3. And a spring (elastic member) 10, an electromagnetic clutch 11 as a control actuator for moving the control holder 7 in the axial direction, and a ball cam mechanism 12 provided between the rotary holder 6 and the control holder 7. It is configured. The housing 4 is fixed to an external member (not shown) and cannot rotate. Further, a compression coil spring is used as the spring 10.

The input shaft 1 includes an engaging portion 1a having a two-sided width (two engaging surfaces parallel to the shaft center and parallel to each other) on the outer periphery, and a small-diameter cylindrical portion 1b protruding from an end surface of the engaging portion 1a. Rotational torque is input from a motor (not shown) as a drive actuator of the rotary positioning device. In addition, although a servo motor or a stepping motor is used as the motor, the drive actuator is not limited to such a motor, and any drive actuator that can stop the rotation of the input shaft 1 in an energized state may be used. Moreover, you may make it input the rotational torque of a drive actuator to the input shaft 1 via a reduction gear.

In the output shaft 2, an engagement hole 2a having a two-sided width is formed in the large diameter portion, and a circular hole 2b having a smaller diameter than the engagement hole 2a is formed on the bottom surface of the engagement hole 2a. In addition, a two-sided width is formed on the outer periphery of the small-diameter portion located on the opposite side of the large-diameter portion in the axial direction, and rotational torque is applied to an output-side member (not shown) that is attached to the small-diameter portion and rotationally positioned. Is output.

The small-diameter cylindrical portion 1b of the input shaft 1 is slidably fitted into the circular hole 2b of the output shaft 2, and the distal end portion of the engaging portion 1a of the input shaft 1 rotates in the engaging hole 2a of the output shaft 2. Torque transmission means is configured to insert the input torque applied to the input shaft 1 to the output shaft 2 with a slight angular delay.

The outer ring 3 is fixed to the housing 4 by a fixing member 13 and is restrained from rotating by the housing 4, and a cylindrical surface is provided on the inner periphery. As shown in FIGS. 2 and 5A, a plurality of cam surfaces 2c are provided on the outer periphery of the large diameter portion of the output shaft 2 arranged on the radially inner side of the outer ring 3, and the inner peripheral cylindrical surface of the outer ring 3 is provided. A wedge-shaped space 14 that is gradually narrowed on both sides in the circumferential direction is formed between each of the cam surfaces 2 c of the output shaft 2. A pair of rollers 9 is incorporated in each wedge-shaped space 14, and the spring 10 is assembled so as to be sandwiched between the pair of rollers 9, and each roller 9 is pushed into a narrow portion of the wedge-shaped space 14. As a result, a locking means for locking the output shaft 2 and the outer ring 3 against the reverse input torque applied to the output shaft 2 is configured between the outer ring 3 and the output shaft 2.

The input side holder 5, the rotary holder 6, and the control holder 7 have

flange portions

5c, 6c, and 7c at one end of the

cylindrical portions

5b, 6b, and 7b, and the

flange portions

5c, 6c, and 7c. The

column portions

5a, 6a and 7a are provided on one side surface.

The input-side cage 5 has a cylindrical portion 5b fitted into the outer periphery of the axially central portion of the engaging portion 1a of the input shaft 1 so as to rotate integrally with the input shaft 1. The rotating cage 6 is slidably fitted on the outer circumference of the cylindrical portion 7 b of the control cage 7, and is supported on the housing 4 via the bearing 15 so as to be rotatable and immovable in the axial direction. The control retainer 7 is provided with annular protrusions on the inner periphery of both ends of the cylindrical portion 7b, and both annular protrusions are slidably fitted on the outer periphery of the output shaft 2, and are supported rotatably and axially movable. Has been.

Further, the flange portion 7 c of the control cage 7 is located between the flange portion 6 c of the rotary cage 6 and the output shaft 2 large diameter portion and the outer ring 3, and is opened in the flange portion 7 c of the control cage 7. The column part 6a of the rotary cage 6 is passed through the window 7d with a circumferential clearance. The column portion 6 a of the rotary cage 6 is inserted between the output shaft 2 and the outer ring 3 at a position facing the spring 10 in the circumferential direction with one of the pair of rollers 9 interposed therebetween. On the other hand, the column portion 7 a of the control holder 7 is inserted between the output shaft 2 and the outer ring 3 at a position facing the spring 10 in the circumferential direction with the other of the pair of rollers 9 interposed therebetween. And the column part 5a of the input side cage 5 is sandwiched between the column part 6a of the rotary cage 6 and the column part 7a of the control cage (the column part 6a of the rotary cage 6 or the column part 7a of the control cage is sandwiched between them). At a position facing the roller 9 in the circumferential direction) between the output shaft 2 and the outer ring 3.

Thereby, when an input torque is applied to the input shaft 1, the input side cage 5 rotates integrally with the input shaft 1, and the column portion 5 a of the input side cage 5 becomes the column portion 6 a of the rotation cage 6. Alternatively, the roller 9 on the rear side in the rotational direction of the pair of rollers 9 is pushed out to the wide portion of the wedge-shaped space 14 via the column portion 7a of the control cage, and the locked state by the locking means is released. . That is, the input side cage 5 serves as a lock release means for releasing the lock state with respect to the input torque applied to the input shaft 1.

As shown in FIG. 3, the engagement piece 8 has a disk shape having a plurality of convex portions 8a projecting radially outward from the outer periphery, and the convex portions 8a are axially connected to the roller 9 and the spring 10. It is attached to the outer periphery of the output shaft 2 so as not to be relatively rotatable so as to be sandwiched between the column portion 6a of the rotary holder 6 and the column portion 7a of the control holder 7 at adjacent positions.

The electromagnetic clutch 11 includes an electromagnet 16 and a cylindrical armature 17 as shown in FIG. The electromagnet 16 includes a core 18 provided with a cylindrical portion 18b extending inward in the axial direction at the edge of the center hole of the disc portion 18a, and an electromagnetic coil 19 wound around the outer periphery of the cylindrical portion 18b of the core 18. The outer peripheral portion of the disk portion 18 a of the core 18 is fixed to the end portion of the housing 4 opposite to the outer ring 3 fixing side with the output shaft 2 penetrating through the output shaft 2. The armature 17 is opposed to the front end of the cylindrical portion 18b of the core 18 in the axial direction, and the end opposite to the flange portion 7c of the control cage 7 through the bearing 20 in a state where the output shaft 2 is rotatably passed. It is integrated in the part.

Thus, when the electromagnetic clutch 11 (the electromagnetic coil 19 of the electromagnet 16) is energized, the armature 17 is attracted to the core 18 of the electromagnet 16 and moves in the axial direction integrally with the control holder 7.

As shown in FIG. 4A, the ball cam mechanism 12 is deep at the center in the circumferential direction and gradually shallows at both sides in the circumferential direction on the opposing surfaces of the flange portion 6c of the rotary retainer 6 and the flange portion 7c of the control retainer 7. A plurality of pairs of

cam grooves

21, 21 are provided so as to face each other, and balls 22 are arranged between each pair of

cam grooves

21, 21. In the clutch assembled state, the

cam grooves

21, 21 facing each other are arranged. The circumferential position is slightly shifted, and the ball 22 is positioned between the circumferential one end side portion of the cam groove 21 of the rotary retainer 6 and the circumferential other end portion of the cam groove 21 of the control retainer 7. . Each cam groove can be not only an arc-shaped groove as in the embodiment but also a V-shaped groove.

When the flange portion 7c of the control cage 7 approaches the flange portion 6c of the rotary cage 6 in the axial direction, both the

cages

6 and 7 are moved in the circumferential direction of the

cam grooves

21 and 21 as shown in FIG. 4B. Relative rotation in the direction of contact with the ball 22 at the center. The direction of this relative rotation is a direction in which the column portion 6a of the rotary holder 6 and the column portion 7a of the control holder 7 that face each other across the pair of rollers 9 and the spring 10 are brought close to each other. .

Therefore, when the electromagnetic clutch 11 is energized, the control cage 7 moves in the axial direction, the flange portion 7c approaches the flange portion 6c of the rotary cage 6, and the two

cages

6 and 7 rotate relative to each other. As shown in FIG. 5B, the

column portions

6a and 7a of both the

retainers

6 and 7 push out the pair of rollers 9 against the elasticity of the spring 10 to the wide portion of the wedge-shaped space 14, and the output shaft 2 by the locking means. And the locked state of the outer ring 3 is released.

Further, at this time, the rotation retainer 6 and the control retainer 7 stop the relative rotation when the

pillar portions

6a and 7a of the

retainers

6 and 7 sandwich the convex portion 8a on the outer periphery of the engagement piece 8, The axial movement of the control holder 7 is also stopped. In this state, even if the output shaft 2 rotates, the engagement piece 8 attached to the output shaft 2 so as not to rotate relative to the output shaft 2 is a pillar portion of one of the rotation retainer 6 and the control retainer 7. When one of the retainers pushes the other retainer via the ball 22 of the ball cam mechanism 12, the

retainers

6 and 7 rotate together with the output shaft 2, so that the cam surface of the output shaft 2 The positional relationship between 2c and the rollers 9 pushed by the

pillars

6a and 7a of the

cages

6 and 7 does not change, and the rollers 9 remain in the wide part of the wedge-shaped space 14, and the unlocked state is held. It will be.

That is, the above-described rotation retainer 6, control retainer 7, engagement piece 8, electromagnetic clutch 11, and ball cam mechanism 12 are used to hold the unlocked holding means that holds the unlocked state by the locking means. Is configured.

When the control cage 7 and the rotary cage 6 driven by the electromagnetic clutch 11 are stopped, the

column portions

6a and 7a of the

cages

6 and 7 do not necessarily sandwich the convex portion 8a of the engagement piece 8. It may not be present (a slight gap may be present between the protrusion 8a of the engagement piece 8). That is, when the output shaft 2 rotates in a state where both the

retainers

6 and 7 are stopped due to the restriction of the axial movement of the control retainer 7 or the like, immediately after that, the engagement piece 8 becomes one of the

retainers

6 and 7. It is only necessary that both the

retainers

6 and 7 rotate integrally with the output shaft 2 to be engaged with the column portion of the retainer so that the unlocked state is retained.

Also, if the energization of the electromagnetic clutch 11 is interrupted in the above-described unlocked holding state, the force of the core 18 of the electromagnet 16 attracting the armature 17 is eliminated, so the elasticity of the spring 10 between the output shaft 2 and the outer ring 3 is eliminated. Each roller 9 is again pushed into the narrow portion of the wedge-shaped space 14, and the rotation cage 6 and the control cage 7 whose

column portions

6 a and 7 a are pushed by the rollers are opposite to the directions when the electromagnetic clutch 11 is energized. The control cage 7 moves in a direction in which its flange portion 7 c is separated from the flange portion 6 c of the rotary cage 6, and returns to the locked state before the electromagnetic clutch 11 is energized.

Next, a control method when the motor is driven and the output side member is rotationally positioned will be described.

Before the rotational positioning is performed, neither the motor nor the electromagnetic clutch 11 is energized, and even if a reverse input torque is applied to the output shaft 2 from the output side member, the output shaft 2 rotates in the rotational direction by the action of the locking means. It is locked to the outer ring 3 via the rear roller 9 so that the rotational position of the output side member does not change.

When rotational positioning is to be performed, as shown in FIG. 6, the motor is energized to start positioning. At the same time, the electromagnetic clutch 11 is energized to start the unlocking operation by the unlocking holding means. After completion, the unlocked state is maintained until positioning is completed. When the positioning is completed, the energization to the electromagnetic clutch 11 is interrupted to start the locking operation, and the energization to the motor is interrupted after the locking is completed.

Here, when energization of the motor is started, the unlocking operation by the unlocking holding unit is started at the same time. However, when the input shaft 1 to which the input torque is applied from the motor starts to rotate, the lock by the unlocking unit is started. The release operation is also started. Since the unlocking means is shorter than the unlocking holding means until the unlocking is completed, when the input shaft 1 starts to rotate due to energization of the motor, the machine by the unlocking means first. Unlocking is performed.

That is, in this control method, when the rotational positioning of the output side member is to be performed, the energization of the motor and the electromagnetic clutch 11 is started simultaneously, thereby energizing the electromagnetic clutch 11 and completing the unlocking by the unlocking holding means. Compared to the case where the motor is energized after this, the response is improved.

In addition, after the unlocking by the unlocking holding means is completed, the unlocked state is held until the positioning is completed, so that the reverse input torque in the same direction as the input torque is applied from the output side member to the output shaft 2. Even if this is done, the output shaft 2 is not re-locked, and smooth rotation transmission can be performed.

Here, the energization of the electromagnetic clutch 11 requires the largest amount of power when the electromagnetic clutch 11 is activated, so that the lock release state is maintained with respect to the power from the start of energization to the completion of unlocking. By reducing the power to a predetermined value, control is performed so as to reduce the power consumption during lock release holding. The predetermined value of the electric power during the unlocking and holding is an electric power value that can hold the state in which the core 18 of the electromagnet 16 attracts the armature 17. Further, in this energization control method, the voltage value may be changed as shown in FIG. 7A, or when the voltage value is constant and controlled by PWM, the duty ratio of the pulse wave is changed as shown in FIG. 7B. It may be changed.

When the positioning is completed and the motor stops the rotation of the input shaft 1, if the energization to the motor and the energization to the electromagnetic clutch 11 are cut off at the same time, the reverse action of the unlocking holding means is reversed. Before returning to the locked state, the output shaft 2 is rotated by applying reverse input torque, and the rotational position of the output side member may change. By turning off the power to the motor after returning to the state, the rotational position of the output side member is prevented from changing due to the reverse input torque.

In the control method described above, the unlocking completion of the unlocking holding means after energization of the electromagnetic clutch 11 and the determination of the completion of locking after the energization of the electromagnetic clutch 11 are interrupted are determined by the energization time and the electromagnetic clutch 11 respectively. This is based on the elapsed time from the energization cutoff time. The reference time is determined based on time data obtained by measurement in advance.

As described above, the control method of the reverse input prevention clutch is such that, even when the input torque and the reverse input torque are simultaneously applied in the same direction during the rotational positioning operation, the unlocked state is maintained and the output shaft 2 is re-locked. Since the phenomenon does not occur, the output shaft 2 can be smoothly rotated, and when the rotation positioning is completed, the motor is cut off after being returned to the locked state. The rotational position of the member is not changed by the reverse input torque, and the rotational positioning operation can be performed efficiently.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Input shaft 2 Output shaft 2c Cam surface 3 Outer ring 4 Housing 5 Input side holder 5a Column part 6 Rotation holder 6a Column part 7 Control cage (lock release member)
7a Column 8 Engagement piece 9 Roller (engagement element)
10 Spring (elastic member)
11 Electromagnetic clutch (control actuator)
12 ball cam mechanism 13 fixing member 14 wedge-shaped space 16 electromagnet 17 armature 21 cam groove 22 ball

Claims

An input shaft to which rotational torque is input from a drive actuator of the rotational positioning device, an output shaft that is arranged coaxially with the input shaft and outputs rotational torque to an output side member that is rotationally positioned, and in a state where the rotation is constrained An outer ring disposed radially outward of the output shaft, and a locking means provided between the outer ring and the output shaft for locking the output shaft and the outer ring against reverse input torque applied to the output shaft; An unlocking means that is provided on the input shaft and releases the locked state by the locking means with respect to the input torque applied to the input shaft, and is applied to the input shaft when the locked state by the locking means is released. Reverse input prevention comprising torque transmission means for transmitting the input torque to be output to the output shaft, and lock release holding means for holding the unlocked state by the lock means A method for controlling a clutch,
The locking means is provided with a cylindrical surface on the inner periphery of the outer ring, a plurality of cam surfaces are provided on the outer periphery of the output shaft, and between the inner peripheral cylindrical surface of the outer ring and each cam surface of the output shaft. Wedge-shaped spaces that are gradually narrowed on both sides in the circumferential direction are formed, a pair of engagement elements in each of these wedge-shaped spaces, and an elastic member that is sandwiched between the pair of engagement elements and pushes each engagement element into the narrow portion of the wedge-shaped space; Is built-in,
The unlocking means rotates integrally with the input shaft when an input torque is applied to the input shaft, and the engagement member on the rear side in the rotation direction of the pair of engagement members To push
In the unlocking holding means, an unlocking member driven by a control actuator engages the pair of engaging elements in a state of pushing the pair of engaging elements into a wide part of the wedge-shaped space and rotating integrally with the output shaft. ,
The drive actuator is energized to start rotational positioning of the output side member. At the same time, the control actuator is energized to start the unlocking operation, and the unlocked state is maintained until the rotational positioning of the output side member is completed. When the rotation positioning of the output side member is completed, the energization to the drive actuator is interrupted after the energization to the control actuator is interrupted.
The control actuator is an electromagnetic clutch, and energization of the electromagnetic clutch lowers the electric power while holding the unlocked state with respect to the electric power from the start of energization to the completion of unlocking. Item 5. A reverse input preventing clutch control method according to Item 1.