JP2006170416A - Rotation transmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a smaller and lighter rotation transmitting device for outputting power input to an input shaft to two outer rings. <P>SOLUTION: The elastic force of a switch spring 14 is imparted to a cage 11 to hold an engaging element 10 at a neutral position. A rotator 24 is opposed to a friction plate 21 in the axial direction, and a pressure ring 22 is provided between opposed portions and a motion converting mechanism 25 is provided between the pressure ring 22 and the rotator 24 for converting the rotating motion of the rotator 24 into axially linear motion of the pressure ring 22. With the rotator 24 rotated by a motor 23, the pressure ring 22 is moved in the axial direction to push the friction plate 21 against the end face of the outer ring 3 so that the engaging element 10 engages with a cylindrical face 8 and a cam face 9 with the rotation of the input shaft 2 relative to the cage 11. Such two sets of rotation transmitting device units (MCU<SB>1</SB>), (MCU<SB>2</SB>) are provided in symmetry with the rotator 24 in common to form the smaller and lighter rotation transmitting device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotation transmission device used for switching between transmission and interruption of driving force in a power transmission path of a vehicle.

  As this type of rotation transmission device, one described in Patent Document 1 has been conventionally known. This rotation transmission device supports an input shaft and an outer ring provided outside thereof in a relatively rotatable manner, and a wedge-shaped space between an outer periphery of the input shaft and a cylindrical surface formed on the inner periphery of the outer ring. A cam surface is formed, and an engaging member made of a roller is incorporated between the cam surface and the cylindrical surface, and the engaging member is held by a cage built between the input shaft and the outer ring, and the switch is switched to the cage. The retainer is elastically held at a neutral position where the engagement element is disengaged from the cam surface and the cylindrical surface by applying the elastic force of the spring.

Further, the armature that is prevented from rotating with respect to the cage and is supported so as to be movable in the axial direction is opposed to the rotor that is prevented from rotating around the outer ring, and the armature is energized by energizing the electromagnetic coil of the electromagnet facing the rotor. The actuator is engaged with the cam surface and the cylindrical surface by rotating the input shaft and the cage relative to the elasticity of the switch spring by the friction force acting on the contact portion by sucking The rotation of the input shaft is transmitted to the outer ring.
JP 11-336799 A

  By the way, in the conventional rotation transmission device, it is necessary to add a frictional resistance large enough to overcome the elastic force of the switch spring to switch the roller to the engaging position when the electromagnetic coil is energized.

  In this case, it is necessary to increase the frictional force acting on the contact portion between the rotor and the armature to prevent slippage at the contact portion. In order to increase the frictional force, it is effective to increase the friction coefficient at the contact portion between the rotor and the armature, or to increase the contact force (coil magnetomotive force) between the rotor and the armature.

  In order to increase the friction coefficient, it is conceivable to attach a friction material used in a wet multi-plate clutch or the like to the contact portion between the rotor and the armature. However, since the friction material is a non-magnetic material, Since the magnetic field transmission is hindered between the rotor and the armature due to the pasting, and the detrimental effect of reducing the attractive force is generated, it cannot be effectively carried out.

  Therefore, in the conventional rotation transmission device, a method of increasing the coil magnetomotive force is adopted. In this case, it is necessary to increase the number of turns of the coil or increase the energization current. When the number of turns of the coil is increased, the size increases and the weight also increases, thereby reducing the size and weight of the rotation transmission device. The problem that it is impossible to plan occurs. On the other hand, in the method of increasing the energization current, there arises a problem that the power consumption increases when the engaging element composed of the roller is engaged. In particular, when energized continuously, the coil may generate heat and burn out. Further, the lubricant is deteriorated by heat generation, and the possibility that the engaging portion of the engaging element is damaged early increases.

  By the way, the above rotation transmission devices may be used side by side in the axial direction. At this time, if the two rotation transmission device units are simply arranged in the axial direction, the torque transmission device itself is increased in size and cost is increased, and there is a problem that the power consumption is extremely increased.

  An object of the present invention is to provide a rotation transmission device that is small, lightweight, and consumes less power so that power input to an input shaft can be output to two outer rings.

  In order to solve the above-described problems, in the present invention, an input shaft and an outer ring provided outside the input shaft are relatively rotatably supported, and a cylinder formed on the outer periphery of the input shaft on the inner periphery of the outer ring. A cam surface that forms a wedge-shaped space between the cam surface and the cylindrical surface is provided, and an engagement element is incorporated between the cam surface and the cylindrical surface, and the engagement element is held by a cage incorporated between the input shaft and the outer ring, A switch spring that holds the cage in a neutral position in which the engagement element is disengaged from the cam surface and the cylindrical surface, and the cage is loaded with a rotational resistance greater than the spring force of the switch spring. And two sets of rotation transmission device units provided with friction resistance applying means for rotating the input shaft relative to each other, and the friction resistance applying means of the two sets of rotation transmission device units rotate with respect to the cage. Stopped and movable in the axial direction of the input shaft A friction plate that is supported and faces the end surface of the outer ring, a pressure ring that is supported so as to be movable in the axial direction that presses the friction plate against the end surface of the outer ring, and a rotation that rotates about the input shaft using a motor as a drive source And a motion conversion mechanism that converts the rotational motion of the rotating body into a linear motion in the axial direction of the pressure ring. The two sets of rotation transmission device units are symmetrical on both sides of the rotating body in common. The configuration provided in is adopted.

  Here, by adopting a configuration in which a gear reduction mechanism is provided between the rotating shaft and the rotating body of the motor to rotate the rotating body, a small motor with a small capacity can be employed, and the rotation transmission device Miniaturization can be achieved.

  As the gear reduction mechanism, a mechanism composed of a worm provided on the rotating shaft of the motor and a worm wheel provided on the outer periphery of the rotating body can be employed.

  Here, by using the rotor forming the motor as a rotating body, the rotation transmission device can be further downsized.

  In the rotation transmission device according to the present invention, the motion conversion mechanism includes a male screw provided at both ends of the outer periphery of the rotating body and a female screw provided on the inner periphery of the pressure ring and screwed to one of the male screws. A cam groove that is deep at the center in the circumferential direction and gradually shallows as it reaches both ends is formed on each of the screw mechanism and the opposing surfaces of the rotating body and the pressure ring, and a ball is incorporated between the cam grooves. A torque cam can be employed. When a screw mechanism is employed as the motion conversion mechanism, the two male screws provided at both ends of the outer periphery of the rotating body may be in the same direction or may be reverse screws.

  Further, in the rotation transmission device according to the present invention, by incorporating a thrust bearing and an elastic body between the friction plate and the pressure ring, the frictional force between the pressure ring and the friction plate can be reduced and retained. The switch can be loaded with a large switch torque.

  According to the above configuration, when the rotating body is rotated by driving the motor, the pressure ring moves in the axial direction, the friction plate is pressed against the end face of the outer ring, and the switch is larger than the spring force of the switch spring. Torque is loaded, and the load of the switch torque causes the input shaft and the cage to rotate relative to each other to engage the engaging element, and the rotation of the input shaft is transmitted to the outer ring. By providing two sets of such rotation transmission device units symmetrically on both sides with a common rotating body, a small and lightweight rotation transmission that can output the power input to the input shaft to the two outer rings. A device can be obtained.

  Further, since the friction plate is pressed against the end face of the outer ring by the rotation of the motor and no magnetic force is used, the friction force can be increased by attaching a friction material to the opposing surface of the friction plate and the outer ring. For this reason, since the switch torque required for engagement of the engagement element can be obtained with a relatively small axial force, a small motor can be employed and a rotation transmission device with low power consumption can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 show a first embodiment of a rotation transmission device according to the present invention.

As shown in FIG. 1, a first rotation transmission unit (MCU ₁ ) and a second rotation transmission unit (MCU ₂ ) are incorporated in the housing 1.

The first rotation transmission device unit and the second rotation transmission device unit (MCU ₂ ) have the same configuration. Therefore, the first rotation transmission unit (MCU ₁ ) will be described below, and the second rotation transmission unit (MCU ₂ ) will be denoted by the same reference numerals for the same parts as the first rotation transmission unit (MCU ₁ ). The description will be omitted.

The first rotation transmission unit (MCU ₁ ) has an input shaft 2 and an outer ring 3 provided outside the input shaft 2. The input shaft 2 is relatively rotatably supported by a bearing 4 incorporated between the outer ring 3 and the outer ring 3 is rotatably supported by a bearing 5 incorporated between the housing 1.

  The input shaft 2 is provided with a large-diameter cam ring 7 at a portion located in the housing 1. As shown in FIGS. 2 and 4, a plurality of cam surfaces 9 forming a wedge-shaped space are formed on the outer periphery of the cam ring 7 with the cylindrical surface 8 formed on the inner periphery of the outer ring 3. An engaging member 10 made of a roller is incorporated between each cam surface 9 and the cylindrical surface 8.

  A cage 11 is assembled between the input shaft 2 and the outer ring 3, and the engaging element 10 is accommodated in a pocket 12 formed in the cage 11.

  A spring housing recess 13 is formed on one end surface of the cam ring 7 in the axial direction, and a switch spring 14 is incorporated in the spring housing recess 13.

  The switch spring 14 has a C shape, and a pair of bent pieces 15 formed outwardly from both ends thereof are formed from one pair of opposed notches 16 formed on the outer peripheral wall of the spring housing recess 13 and one of the cages 11. It is inserted into a notch 17 provided on the end face and presses the circumferentially opposed side surfaces of the notch 16 and the notch 17 in opposite directions, whereby the engaging element 10 causes the cylindrical surface 8 and cam surface 9 to be pressed. The retainer 11 is elastically held in the neutral position where the engagement is released.

  As shown in FIG. 1, friction resistance applying means 20 that applies a friction torque larger than the spring force of the switch spring 14 to the retainer 11 to rotate the retainer 11 relative to the input shaft 2 is provided inside the housing 1. Is provided.

  As shown in FIGS. 2 and 3, the frictional resistance imparting means 20 includes a friction plate 21 that faces the end face of the outer ring 3 in the axial direction, a pressure ring 22 that faces the friction plate 21 in the axial direction, and the housing 1. A rotating body 24 rotated about the input shaft 2 using a motor 23 supported by the motor as a driving source, and a motion conversion mechanism 25 for converting the rotational motion of the rotating body 24 into a linear motion in the axial direction of the pressure ring 22; have.

  The friction plate 21 is movable in the axial direction along the outer periphery of the input shaft 2, and is prevented from rotating on the cage 11 via a connecting plate 26 incorporated in the end of the cage 11. That is, an L-shaped engagement piece 27 formed at a position opposite to the outer periphery of the connecting plate 26 is fitted into the notch 17 provided at the end of the retainer 11 to prevent the connecting plate 26 from rotating. The coupling piece 27 is engaged with an engagement hole 28 formed in the friction plate 21 to prevent the friction plate 21 from rotating. The friction plate 21 is pressed in a direction away from the end face of the outer ring 3 by a separation spring 29 incorporated between the friction plate 21 and the connecting plate 26.

  The rotating body 24 is rotatably supported by a bearing 30 incorporated between the rotating body 24 and the inner periphery of the rotating body 24 and a retaining ring 31 attached to the outer periphery of the input shaft 2. It is said that.

  A gear reduction mechanism 32 is provided between the rotating body 24 and the rotating shaft 23 a of the motor 23. The gear reduction mechanism 32 includes a worm 33 provided on the rotary shaft 23 a and a worm wheel 34 provided on the outer periphery of the rotary body 24, and the rotation of the worm 33 is reduced to the rotary body 24 via the worm wheel 34. To communicate.

  As shown in FIGS. 1 and 3, the pressure ring 22 is prevented from rotating around the housing 1 via a rotation stop mechanism 35 and is movable in the axial direction of the input shaft 2. The anti-rotation mechanism 35 forms an anti-rotation groove 36 parallel to the input shaft 2 on the inner periphery of the housing 1, and a protrusion 37 provided on the outer periphery of the pressure ring 22 is slidably inserted into the anti-rotation groove 36. ing.

  As shown in FIG. 2, the motion conversion mechanism 25 that converts the rotational motion of the rotating body 24 into the linear motion in the axial direction of the pressure ring 22 includes a male screw 38 provided on the outer periphery of the rotating body 24, and the pressure ring 22. It consists of the screw mechanism formed with the internal thread 39 formed in the inner periphery.

  Between the friction plate 21 and the pressure ring 22, a thrust bearing 40 for reducing the frictional force between the friction plate 21 and the pressure ring 22, and a screw gap between the male screw 38 and the female screw 39 are put together to pressurize the pressure ring. The elastic body 41 which suppresses the backlash of 22 axial directions is integrated. Here, a thrust needle roller bearing is used as the thrust bearing 40. Further, a disc spring is used as the elastic body 41.

The first rotation transmission unit (MCU ₁ ) has the above-described structure, and the first rotation transmission unit (MCU ₁ ) and the second rotation transmission unit (MCU ₂ ) have friction resistance as shown in FIG. The rotating body 24 of the means 20 is common and is arranged symmetrically on both sides.

  The input shaft 2 is divided into two parts in the axial direction, and coupled and integrated by engagement of a spline shaft 2a provided on one of the divided surfaces and a spline hole 2b provided on the other.

  Further, the rotating body 24 is formed with two male screws 38 at both ends of the outer periphery. The two male screws 38 may be screws in the same direction, or may be reverse screws.

The rotation transmission device shown in the first embodiment has the above-described structure. FIGS. 1 and 2 show that the friction plate 21 of the first and second rotation transmission device units (MCU ₁ ) and (MCU ₂ ) is the outer ring 3. The state which separated from the end surface and has both members in non-contact is shown.

  At this time, the retainer 11 is held in a neutral position where the engagement element 10 is disengaged from the cylindrical surface 8 and the cam surface 9 by the spring force of the switch spring 14 (see FIG. 4).

  For this reason, even if the input shaft 2 rotates, the rotation is not transmitted to the outer ring 3, and only the input shaft 2 rotates.

  When the motor 23 shown in FIG. 3 is driven while the input shaft 2 is rotating, the rotation of the rotating shaft 23 a of the motor 23 is transmitted to the rotating body 24 via the gear reduction mechanism 32.

  At this time, the male screw 38 on the outer periphery of the rotating body 24 and the female screw 39 of the pressure ring 22 are screw-engaged, and the pressure ring 22 is prevented from rotating by the engagement of the rotation prevention groove 36 and the projection 37. The pressure ring 22 moves in the axial direction.

Here, if the two male screws 38 formed at both ends of the outer periphery of the rotating body 24 are screws in the same direction, the pair of pressure rings 22 screw-engaged with the two male screws 38 are in the same direction. Therefore, when the motor 23 is rotated (forward rotation) so that the pressure ring 22 on the first rotation transmission unit (MCU ₁ ) side moves toward the friction plate 21, the pressure moves in the axial direction. The ring 22 presses the friction plate 21 via the elastic body 41 and the thrust bearing 40, and the friction plate 21 is pressed against and contacts the end face of the outer ring 3.

When the friction torque (switch torque) acting on the contact portion between the friction plate 21 and the outer ring 3 exceeds the spring force of the switch spring 14, the cage 11 rotates relative to the input shaft 2, and the relative rotation causes the first rotation. An engagement element 10 on the one-rotation transmission unit (MCU ₁ ) side engages with the cylindrical surface 8 and the cam surface 9. For this reason, the rotation of the input shaft 2 is transmitted to the outer ring 3 via the engagement element 10.

On the other hand, the pressure ring 22 on the second rotation transmission unit (MCU ₂ ) side moves in a direction away from the friction plate 21, so that the engagement element 10 of the second rotation transmission unit (MCU ₂ ) is in the neutral position. The rotation of the input shaft 2 is not transmitted to the outer ring 3.

When the motor 23 is reversely rotated in the power transmission state in which the engaging element 10 of the first rotation transmission unit (MCU ₁ ) engages with the cylindrical surface 8 and the cam surface 9, the first rotation transmission unit (MCU ₁ ) The pressure ring 22 moves in a direction away from the friction plate 21. Since the friction plate 21 is released from the movement by the movement, the friction plate 21 is separated from the end surface of the outer ring 3 by the pressing of the separation spring 29, and the retainer 11 causes the engagement element 10 to move the cylindrical surface 8 by the spring force of the switch spring 14. And the neutral position where the engagement with the cam surface 9 is released is returned. For this reason, the rotation of the input shaft 2 is not transmitted to the outer ring 3, and only the input shaft 2 rotates.

On the other hand, if the two male screws 38 formed at both ends of the outer periphery of the rotating body 24 are reverse screws, the pair of pressure rings 22 that are screw-engaged with the two male screws 38 move in the opposite direction. To do. Therefore, when the rotating body 24 is rotated so that each pressure ring 22 moves toward the opposing friction plate 21, the friction plate 21 is pressed against the end face of the outer ring 3 by the pressure ring 22 moving in the axial direction. Switch torque is applied to the retainer 11 of the units (MCU ₁ ) and (MCU ₂ ), and the engaging element 10 engages with the cylindrical surface 8 and the cam surface 9. Therefore, the rotation of the input shaft 2 is transmitted to each of the outer rings 3 of the units (MCU ₁ ) and (MCU ₂ ).

  Further, when the rotating body 24 is rotated in the reverse direction, the pair of pressure rings 22 move in a direction away from the friction plate 21, and the pressing of the friction plate 21 is released by the movement, and the spring of the switch spring 14. Due to the force, the retainer 11 is returned to the neutral position where the engagement element 10 is disengaged from the cylindrical surface 8 and the cam surface 9, and power transmission to the outer ring 3 is interrupted.

In the rotation transmission device shown in the first embodiment, as described above, the rotation of the rotating shaft 23a of the motor 23 is transmitted to the rotating body 24 via the gear reduction mechanism 32, and the rotating motion of the rotating body 24 is externally threaded. Since the friction plate 21 is pressed against the end face of the outer ring 3 by converting into a linear motion in the axial direction of the pressure ring 22 via the screw mechanism of the screw 38 and the female screw 39, the cage 11 is held by the small motor 23 having a small capacity. It is possible to load a switch torque larger than the spring force of the switch spring 14. Since the engagement element 10 is engaged by the load of the switch torque, the power input to the input shaft 2 can be output to the outer ring 3. Then, two sets of such rotation transmission device units (MCU ₁ ) and (MCU ₂ ) are provided symmetrically on both sides of the rotating body 24 in common, so that the power input to the input shaft 2 is A small and lightweight rotation transmission device that can output to each of the outer rings 3 can be obtained.

  Further, since the friction plate 21 is pressed against the end surface of the outer ring 3 by the rotation of the motor 23 and no magnetic force is used, a friction material can be attached to the opposing surface of the friction plate 21 and the end surface of the outer ring 3. In this case, since the switch torque necessary for engaging the engaging element 10 can be obtained with a smaller axial force, the motor 23 can be further reduced in size.

  Further, by incorporating the thrust bearing 40 and the elastic body 41 between the pressure ring 22 and the friction plate 21, the thrust bearing 40 reduces the frictional force between the pressure ring 22 and the friction plate 21. Can be planned. As a result, a large switch torque (friction torque) can be applied to the cage 11. Further, by incorporating the elastic body 41, it is possible to eliminate backlash of the gear reduction mechanism 32 and axial backlash of the pressure ring 22 due to the screw gap of the screw mechanism, and to the thrust bearing 40 when the friction plate 21 contacts the outer ring 3. An excessive load can be prevented.

  FIG. 5 shows a second embodiment of the rotation transmission device according to the present invention. This embodiment is different from the rotation transmission device shown in the first embodiment in that a stator 44 forming the motor 23 is attached to the inner periphery of the housing 1 and a rotor rotated by the stator 44 is a rotating body 45. ing. For this reason, the same code | symbol is attached | subjected to the components same as the rotation transmission apparatus shown in 1st Embodiment, and description is abbreviate | omitted. Like the rotation transmission device shown in the second embodiment, the number of parts can be reduced by using the rotor of the motor 23 as the rotating body 45, and the rotation transmission device can be made smaller and lighter.

  6 to 8 show a third embodiment of the rotation transmission device according to the present invention. The rotation transmission device shown in the third embodiment is different from the rotation transmission device of the first embodiment shown in FIG.

  For this reason, the same code | symbol is attached | subjected to the components same as the rotation transmission apparatus shown in 1st Embodiment, and description is abbreviate | omitted.

  The motion conversion mechanism 25 shown in the third embodiment is composed of a torque cam. The torque cam is provided with a plurality of cam grooves 51 and 52 which are deep in the center portion in the circumferential direction and gradually shallower toward both ends on the opposing surfaces of the rotating body 24 and the pressure ring 22 at intervals in the circumferential direction. The ball 53 is assembled between a pair of cam grooves 51 and 52 that face each other in the axial direction.

  In the torque cam having the above-described configuration, when the rotating body 24 is rotated by driving the motor 23, the rotating body 24 rotates relative to the pressure ring 22 that is prevented from rotating, and the relative rotation is shown in FIG. As shown in II), the pair of cam grooves 51 and 52 opposed in the axial direction are displaced in the circumferential direction, and the pressure ring 22 moves in the axial direction to press the friction plate 21 against the end face of the outer ring 3.

  In the rotation transmission device using the torque cam as described above, as in the rotation transmission device shown in the first embodiment, a large axial force can be obtained with the small motor 23, and the power consumption can be reduced. The transmission device can be reduced in size and weight.

  The torque cam is not limited to the one shown in FIG. 8, and for example, a cam groove as shown in FIG. 8 (I) is provided on one of the opposed surfaces of the pressure ring 22 and the rotating body 24, and the cam groove is almost on the other. A cam projection that fits snugly may be provided. A roller may be used instead of the ball (steel ball).

1 is a longitudinal front view showing a first embodiment of a rotation transmission device according to the present invention. Sectional drawing which expands and shows a part of FIG. Sectional view along line III-III in FIG. Sectional view along line IV-IV in FIG. Sectional drawing which shows 2nd Embodiment of the rotation transmission apparatus which concerns on this invention Sectional drawing which shows 3rd Embodiment of the rotation transmission apparatus which concerns on this invention Sectional drawing along the VII-VII line of FIG. (I) is an enlarged sectional view of the torque cam, and (II) is a sectional view showing the operating state.

Explanation of symbols

MCU ₁ First rotation transmission unit MCU ₂ Second rotation transmission unit 2 Input shaft 3 Outer ring 8 Cylindrical surface 9 Cam surface 10 Engagement element 11 Cage 14 Switch spring 20 Friction resistance applying means 21 Friction plate 22 Pressure ring 23 Motor 24 Rotating Body 25 Motion Conversion Mechanism 32 Gear Reduction Mechanism 38 Male Thread 39 Female Thread 40 Thrust Bearing 41 Elastic Body 45 Rotating Body 51 Cam Groove 52 Cam Groove 53 Ball

Claims (8)

  A cam surface that forms a wedge-shaped space between the input shaft and an outer ring provided on the outer side of the input shaft and a cylindrical surface formed on the inner periphery of the outer ring is supported on the outer periphery of the input shaft. An engagement element is installed between the cam surface and the cylindrical surface, and the engagement element is held by a cage assembled between the input shaft and the outer ring, and the engagement element is engaged with the cam surface and the cylindrical surface. A switch spring for holding the cage in the released neutral position, and a frictional resistance applying means for rotating the input shaft relative to the cage by applying a rotational resistance larger than the spring force of the switch spring to the cage. Two sets of rotation transmission device units are provided, and the frictional resistance imparting means of the two sets of rotation transmission device units are prevented from rotating with respect to the cage and are movable in the axial direction of the input shaft. A friction plate supported and opposed to the end face of the outer ring; A pressure ring that is supported so as to be movable in the axial direction for pressing the friction plate against the end face of the outer ring, a rotating body that rotates about the input shaft using a motor as a driving source, and a rotating ring that rotates the rotating body A rotation transmission device comprising: a motion conversion mechanism that converts linear motion in the axial direction of the two, wherein the two sets of rotation transmission device units are provided symmetrically on both sides of the rotating body in common.   The rotation transmission device according to claim 1, wherein the rotation of the motor is transmitted to a rotating body via a gear reduction mechanism.   The rotation transmission device according to claim 1, wherein the rotating body is a rotor forming a motor.   4. The motion conversion mechanism according to claim 1, wherein the motion conversion mechanism includes two male screws provided at both ends of the outer periphery of the rotating body and a female screw provided on the inner periphery of the pressure ring and engaged with one of the male screws. The rotation transmission device according to any one of the above.   The rotation transmission device according to claim 4, wherein two male screws provided at both ends of the outer periphery of the rotating body are screws in the same direction.   The rotation transmission device according to claim 4, wherein two male screws provided at both ends of the outer periphery of the rotating body are reverse screws.   The motion conversion mechanism forms cam grooves deeper in the center in the circumferential direction and gradually shallower toward both ends on each of the opposing surfaces of the rotating body and the pressure ring, and balls are incorporated between the cam grooves. The rotation transmission device according to claim 1, comprising a torque cam.   The rotation transmission device according to any one of claims 1 to 7, wherein a thrust bearing and an elastic body are incorporated between the friction plate and the pressure ring.

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