JP2018009601A - Rotational force transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotational force transmission device capable of efficiently transmitting rotational force while properly preventing application of an excessive load exceeding a set torque even for torque transmission in a transmission portion and a transmitted portion, which have relatively small radii.SOLUTION: A cylindrical base portion N2 of a driven rotation part N is fitted externally on the base end side of a shaft portion D3 of a driving rotation part D in a rotatable and coaxial manner, and a compression coil spring S is fitted externally on the shaft portion D3 between the cylindrical base portion N2 of the driven rotation part N and an enlarged diameter tip portion D4. Wave-shaped portions Dw, Nw are provided on a transmission portion D1 of the driving rotation part D and a transmitted portion N1 of the driven rotation part N to face each other in the axial direction. By the urging of the compression coil spring S, required rotational force is transmitted through the engagement of the wave-shaped portions Dw, Nw when a torque is less than a set torque. The engagement between the wave-shaped portions Dw, Nw is released by a load equal to or larger than the set torque, and the transmission of required rotational force is interrupted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotational force transmission device that transmits rotational force while appropriately preventing an excessive load exceeding a set torque from being applied by a transmission portion of a drive rotation portion and a transmitted portion of a driven rotation portion.

  Japanese Patent Application Laid-Open No. 11-191250 describes a torque limiter in which a felt is attached to a slip plate and a pulley is pressed against the felt by a spring and rotates while sliding around the collar with the felt.

  This technology is suitable for transmitting torque while limiting torque by sliding with felt at a radius position that is somewhat large, but it is appropriate to transmit torque between rotors with relatively small radii efficiently. Not suitable for limiting.

JP 11-191250 A

  The present invention is capable of efficiently transmitting a rotational force while appropriately preventing an excessive load exceeding a set torque from being applied even when the rotational force is transmitted in a relatively small radius transmitting portion and a transmitted portion. An object is to provide a force transmission device.

  The rotational force transmission device of the present invention can be expressed as follows.

(1) A device that transmits a rotational force by a transmission unit of a driving rotation unit and a transmitted unit of a driven rotation unit,
The transmitting portion and the transmitted portion are opposed to each other in the axial direction, and an axial force in a direction to separate in the axial direction is transmitted between the transmitting portion and the transmitted portion in accordance with the transmission of the rotational force around the axial direction. Can occur,
The transmitting part and the transmitted part may move relatively in the axial direction between a mutual position where the required rotational force can be transmitted and a mutual position where the required rotational force cannot be transmitted,
One or both of the drive rotation unit and the driven rotation unit are applied with an urging force facing each other in the axial direction.
In a load less than the set torque, a state in which a required rotational force can be transmitted between the transmission unit and the transmitted unit by the urging force in the axial direction is maintained.
When a load greater than a set torque is applied, the transmission of the required rotational force is interrupted by the movement of the transmitting part and the transmitted part in a direction that is relatively separated in the axial direction against the urging force, When the load returns to less than a set torque, a state where a required rotational force can be transmitted between the transmission unit and the transmitted unit is recovered.

  The transmission unit of the drive rotation unit and the transmitted unit of the driven rotation unit can move relatively in the axial direction between a mutual position where the required rotational force can be transmitted and a mutual position where the required rotational force cannot be transmitted. .

  In a load less than the set torque, a state in which a required rotational force can be transmitted between the transmitting portion and the transmitted portion is maintained by the urging forces facing each other in the axial direction.

  When a load exceeding the set torque is applied, the transmission of the required rotational force is interrupted by the movement of the transmitting part and the transmitted part in a direction that is relatively separated in the axial direction against the urging force, and the load is reduced. By returning to less than the set torque, a state in which a required rotational force can be transmitted between the transmission unit and the transmitted unit is recovered.

  Therefore, even if it is rotational force transmission in the transmission part of a comparatively small radius, and a to-be-transmitted part, a rotational force can be transmitted efficiently, preventing appropriately the excessive load exceeding setting torque.

(2) A wave shape portion having an amplitude in the axial direction with a predetermined central angle as a period is provided in each annular portion having a predetermined radial width centered on at least the rotation axis in both the transmission portion and the transmitted portion,
When the load is less than the set torque, the axial position of the transmitting portion and the transmitted portion is maintained within a predetermined range by the axial urging force, and the required rotational force is transmitted by the meshing of the corrugated portions. State that can be done,
When a load greater than the set torque is applied, both the wave-shaped portions resist the urging force and the transmitting portion and the transmitted portion are separated from each other in the axial direction relative to a predetermined range, and the meshing is performed. The rotational force transmission device according to (1) above, wherein transmission of a required rotational force is interrupted due to being released or insufficient.

(3) A large number of convex portions are provided on any one of the transmission portion and the transmitted portion, and a large number of convex portions or concave portions are provided on the other side,
When the load is less than the set torque, the axial directional force between the transmitting portion and the transmitted portion is maintained within a predetermined range by the above-described axial urging force, and the required amount is obtained by engaging both convex portions or convex portions and concave portions. The state where the rotational force can be transmitted is maintained,
When a load greater than the set torque is applied, the convex portions of the two or the convex portions and the concave portions separate the transmitting portion and the transmitted portion in the axial direction relative to the predetermined range against the urging force. The rotational force transmission device according to (1), wherein the meshing is released or insufficient and transmission of a required rotational force is interrupted.

  (4) The rotational force transmission device according to any one of (1) to (3), wherein the transmission unit of the drive rotation unit and the transmission unit of the driven rotation unit are coaxial.

  (5) The other rotating part is coaxially fitted to the rotating part of either the driving rotating part or the driven rotating part so as to be relatively rotatable, and the required rotational force is transmitted between the transmitting part and the transmitted part. The drive rotation unit and the driven rotation unit can move relatively in the axial direction between the mutual position where the required rotational force cannot be transmitted and the one or both of the drive rotation unit and the driven rotation unit. The rotational force transmitting device according to (4), wherein biasing forces facing each other in the axial direction are applied so that a required rotational force can be transmitted between the transmitting portion and the transmitted portion.

  (6) The drive rotation unit and the driven rotation unit are rotatably fitted coaxially to the non-rotating shaft body so that the required rotational force can be transmitted between the transmission unit and the transmitted unit and the required position. The driving rotating part and the driven rotating part can move relatively in the axial direction between the mutual positions where the rotational force cannot be transmitted, and the transmitting part and the transmitted part are in relation to one or both of the driving rotating part and the driven rotating part. The rotational force transmitting device according to (4) above, wherein urging forces in directions facing each other in the axial direction are applied so that a required rotational force can be transmitted between them.

  (7) The rotational force transmission device according to any one of (1) to (6), wherein the driven rotating portion is provided with an output arm-like portion having a radially outward component.

  (8) The rotational force transmission device according to any one of (1) to (7), wherein the set torque is substantially constant regardless of a rotation direction.

  (9) The rotational force transmission device according to any one of (1) to (8), wherein the urging force in the axial direction is an elastic urging force by an elastic body.

  According to the rotational force transmission device of the present invention, in a load less than the set torque, a state in which a required rotational force can be transmitted between the transmission unit and the transmitted unit by the urging forces facing each other in the axial direction is maintained. When a load greater than the set torque is applied, the transmission of the required rotational force is interrupted by the movement of the transmitting portion and the transmitted portion relative to each other in the axial direction against the biasing force, By returning the load to less than the set torque, the state in which the required rotational force can be transmitted between the transmission unit and the transmitted unit is restored, so that the rotational force is transmitted between the transmission unit and the transmitted unit having a relatively small radius. However, it is possible to efficiently transmit the rotational force while appropriately preventing an excessive load exceeding the set torque from being applied.

It is a disassembled perspective view. It is a perspective view of a rotational force transmission state. It is a perspective view of a torque transmission interruption state.

  [1] A rotational force transmission device as an example of an embodiment of the present invention will be described with reference to the drawings.

  The rotational force transmission device A of this example is a driven rotation coaxially fitted so as to be rotatable and slidable in the axial direction with respect to the transmission portion D1 of the drive rotation portion D and the rotation portion of the drive rotation portion D. The rotational force is transmitted from the drive rotating part D to the driven rotating part N by the transmitted part N1 of the part N.

  The drive rotating part D is composed of a base end part D2, a shaft part D3 having a diameter smaller than that of the base end part D2, and a disk-shaped enlarged diameter front end part D4 formed coaxially on the tip side of the shaft part D3. . The output shaft M1 of the electric motor M, which is a power source, and the base end portion D2 and the base portion of the shaft portion D3 are connected to each other so as not to be relatively rotatable by inserting pins P through holes respectively penetrating them.

  The driven rotating portion N includes a cylindrical base portion N2 and an output arm-like portion N3 that protrudes radially outward from the cylindrical base portion N2. The distal end portion of the output arm N3 acts on an operation target member (not shown), and the operation target member is operated by either or both of the forward rotation and the reverse rotation of the cylindrical base N2.

  A cylindrical base portion N2 in the driven rotating portion N is rotatably fitted coaxially on the proximal end side of the shaft portion D3, and between the cylindrical base portion N2 and the diameter-expanded distal end portion D4 of the shaft portion D3, A compression coil spring S is externally fitted.

  Of the base end portion D2 of the driving rotating portion D, the annular end surface portion on the distal end side constitutes the transmitting portion D1, and among the cylindrical base portion N2 of the driven rotating portion N, the annular portion facing the transmitting portion D1 in the axial direction is transmitted. Part N1 is configured.

  Each of the transmitting part D1 and the transmitted part N1 is provided with triangular wave-shaped parts Dw and Nw having an isosceles triangular waveform having a predetermined center angle in the circumferential direction as opposed to each other in the axial direction. ing. The waveform part Dw and the waveform part Nw are the same. Between the transmission part D1 and the transmitted part N1, an axial force in a direction that tends to be separated in the axial direction can be generated with the transmission of the rotational force around the axial direction.

  In the driven rotating part N, the wave-shaped part Nw of the transmitted part N1 meshes with the wave-shaped part Dw of the transmitting part D1 in the driving rotating part D, and the required rotational force is transmitted from the driving rotating part D to the driven rotating part N. 2. Obtain the axial position as shown in FIG. 2 (the axial position where the wave-shaped parts Dw and Nw of the transmitted part N1 and the transmitted part D1 are deeply engaged), the wave-shaped part Nw of the transmitted part N1 and the drive rotating part. The engagement of the wave-shaped portion Dw of the transmission portion D1 in D is released or insufficient, and transmission of the required rotational force is interrupted. It can move in the axial direction between axial positions as shown in FIG. .

  Since the driven rotating part N is urged in the axial direction toward the transmitting part D1 by the compression coil spring S, the torque (load) to be transmitted from the driving rotating part D to the driven rotating part N is less than the set torque. In this case, the wave shape portion Nw of the transmitted portion N1 is deeply engaged with the wave shape portion Dw of the transmission portion D1 in the drive rotation portion D so that a required rotational force can be transmitted from the drive rotation portion D to the driven rotation portion N. The axial position as shown in 2 is maintained.

  When a load greater than the set torque is applied, the driven rotating portion N having the transmitted portion N1 is compressed with respect to the transmitting portion D1 due to the engagement between the wave-shaped portions Dw and Nw of the transmitted portion N1 and the transmitting portion D1. Pushing in the axial direction against the urging force of the coil spring S, the transmission of the required rotational force is interrupted, and the drive rotating part D is idled with respect to the driven rotating part N. If a load equal to or greater than the set torque continues, the mutual position in the axial direction of the transmitted portion N1 and the transmitting portion D1 varies depending on the phase change of the waveform portion Dw and the waveform portion Nw due to the rotation of the drive rotation portion D .

  When the load returns below the set torque, the urging force of the compression coil spring S maintains the state in which the wave-shaped portions Dw and Nw of the transmitted portion N1 and the transmitting portion D1 are deeply engaged with each other, and the required rotational force can be transmitted. The state recovers.

  In this way, even when the rotational force is transmitted in the relatively small radius transmission part D1 and the transmitted part N1, the rotational force is efficiently transmitted while appropriately preventing an excessive load exceeding the set torque from being applied. Can do. For example, by rotating the output shaft of the power source forward or reverse at a predetermined rotation angle, the driven rotation portion N can be driven to rotate, and the operation target member can be operated via the output arm-shaped portion N3. When an unexpected load or the like is loaded on the target member and an excessive load exceeding the set torque is applied between the transmitting portion D1 and the transmitted portion N1, both wave-shaped portions Dw · of the transmitted portion N1 and the transmitting portion D1 It is prevented that the meshing between the Nw is released or insufficient and the transmission of the required rotational force is interrupted, causing inconvenience such as damage to the power source or other parts.

  [2] Embodiments of the rotational force transmission device of the present invention will be further described, including forms other than those described above.

  The rotational force transmission device of the present invention transmits a rotational force from the drive rotation unit to the driven rotation unit by the transmission unit of the drive rotation unit and the transmitted unit of the driven rotation unit.

  (1) Drive rotation unit and driven rotation unit

  Examples of the drive rotation unit include, but are not limited to, an electric motor or an output shaft of a power source in which an electric motor is combined with a reduction gear or the like, or a rotation unit coupled to the output shaft.

  Examples of the driven rotating unit include, but are not limited to, a driven shaft and a driven annular unit that are rotationally driven by the rotational force of the driving rotating unit.

  The drive rotation unit and the driven rotation unit are preferably coaxial and rotate around the same rotation axis, but are not necessarily limited thereto.

  (2) Transmitter and receiver

  (2-1) The transmitting part of the driving rotating part and the transmitted part of the driven rotating part are opposite to each other in the axial direction, and the rotational force of the rotation around the axial direction is between the transmitting part and the transmitted part. Along with the transmission, an axial force in the direction of separating in the axial direction can be generated. The transmitting part and the transmitted part move relative to each other in the axial direction between a mutual position where the required rotational force can be transmitted between them and a mutual position where the required rotational force cannot be transmitted. In addition, an urging force in a direction facing each other in the axial direction is applied to one or both of the drive rotation unit and the driven rotation unit.

  The urging force is preferably an elastic urging force. For example, an elastic biasing force by an elastic body such as a compression coil spring or a tension coil spring can be mentioned, but the present invention is not limited to this.

  As such a configuration, for example, a columnar or cylindrical drive rotation unit and a driven rotation unit are arranged coaxially so that one or both of them can move in the axial direction, and the drive rotation unit and One or both of the driven rotating parts may be those in which an urging force in the axial direction by a compression coil spring or the like is applied so that a required rotational force can be transmitted between the transmitting part and the transmitted part.

As a more specific example of such a configuration,
Mutually independent of each other (including those that are rotatably supported on the same base via support bodies, etc.), and the mutual position and required position where the required rotational force can be transmitted between the transmitting part and the transmitted part The drive rotation unit and the driven rotation unit can move relatively in the axial direction between the mutual positions where the rotational force of the motor cannot be transmitted, and the transmission unit and the transmitted unit are transmitted to one or both of the drive rotation unit and the driven rotation unit. A biasing force applied in a direction facing each other in the axial direction by a compression coil spring or the like so that a required rotational force can be transmitted between the parts,
The other rotating part is coaxially fitted on the rotating part such as the rotating shaft in either the driving rotating part or the driven rotating part so as to be relatively rotatable, and a required rotational force is applied between the transmitting part and the transmitted part. The drive rotation unit and the driven rotation unit can move relatively in the axial direction between the mutual position where the transmission force can be transmitted and the mutual position where the required rotational force cannot be transmitted, to one or both of the drive rotation unit and the driven rotation unit. On the other hand, a biasing force applied in a direction facing each other in the axial direction by a compression coil spring or the like is applied so that a required rotational force can be transmitted between the transmission unit and the transmission unit,
The non-rotating shaft body (which may be solid or cylindrical) has a drive rotation unit and a driven rotation unit that are rotatably fitted coaxially so that the required rotational force is transmitted between the transmission unit and the transmitted unit. The drive rotation unit and the driven rotation unit can move relatively in the axial direction between the mutual position to be obtained and the mutual position where the required rotational force cannot be transmitted, with respect to one or both of the drive rotation unit and the driven rotation unit, A biasing force applied in a direction facing each other in the axial direction by a compression coil spring or the like so that a required rotational force can be transmitted between the transmitting portion and the transmitted portion,
And so on.

  For example, the driven rotating portion is linear, bent, or curved, such as a working arm having a radially outward component (may have an axial component), a connecting rod, a connecting rod via a crankshaft, or the like. An output arm-like portion may be provided.

  (2-2) As the transmission part of the drive rotation part, for example, the tip of the output shaft of the power source, the annular end face part (annular end face part formed by expanding or contracting diameter), and rotational symmetry around the rotation axis For example, the bottom part of the recessed part formed in the shape can be mentioned.

As a basic shape of the transmission unit of the drive rotation unit, for example, in a drive rotation unit of a columnar shape, a cylindrical shape or other cross-sectional shape,
An end surface portion orthogonal to the rotation axis (for example, a circular or annular end surface portion),
A portion corresponding to a frustoconical outer peripheral surface portion that decreases in diameter toward the tip or a frustoconical inner peripheral surface portion that increases in diameter toward the tip,
A cone-shaped outer peripheral surface portion that decreases in diameter toward the tip, or a conical inner peripheral surface portion that increases in diameter toward the tip,
Hemispherical convex surface or concave surface or other curved convex surface or concave surface, or
A predetermined annular portion centering on the rotation axis in these,
Although the thing which forms the rotary body centering on the rotating shaft line of a drive rotation part, or the thing which makes a rotation symmetry around the rotation axis line of a drive rotation part can be mentioned, It is not restricted to these.

  (2-3) The transmitted part of the driven rotating part is, for example, rotationally symmetric around the driven shaft rotated by the rotational force of the driving rotating part, the tip of the driven annular part, the enlarged diameter part, and the rotational axis. The bottom part of the recessed part formed in can be mentioned.

  The basic shape of the transmitted portion of the driven rotating portion is a shape corresponding to the shape of the transmitting portion so that a required rotational force can be transmitted to the transmitting portion.

When the basic shape of the transmission part is the shape as described above, the basic shape of the transmitted part of the driven rotation part is a shape corresponding to each, for example,
In a driven rotating part of a columnar shape, a cylindrical shape or other cross-sectional shape,
An end surface portion orthogonal to the rotation axis (for example, a circular or annular end surface portion),
A portion corresponding to a frustoconical inner peripheral surface portion that expands toward the tip or a frustoconical outer peripheral surface portion that decreases in diameter toward the tip,
A conical inner peripheral surface portion that expands toward the tip, or a conical outer peripheral surface portion that decreases in diameter toward the tip,
Hemispherical concave or convex surface or other curved concave or convex surface, or
A predetermined annular portion centering on the rotation axis in these,
Examples include, but are not limited to, those that form a rotating body about the rotation axis of the driven rotation unit and those that are rotationally symmetric around the rotation axis of the driven rotation unit.

(2-4) The form of the surface part in the basic shape of the transmitting part and the transmitted part is
Between the transmission part and the transmitted part in a state opposed to the axial direction, an axial force in a direction to be separated in the axial direction can be generated along with the transmission of the rotational force around the axial direction,
In a load less than the set torque, a state in which a required rotational force can be transmitted between the transmitting unit and the transmitted unit by the biasing forces facing each other in the axial direction is maintained.
When a load greater than a set torque is applied, the transmission of the required rotational force is interrupted by the movement of the transmitting part and the transmitted part in a direction that is relatively separated in the axial direction against the urging force, When the load returns to less than the set torque, it is necessary that the state in which a required rotational force can be transmitted between the transmission unit and the transmitted unit is recovered.

As an example of the combination of the form of the surface part in the basic shape of the transmission part and the form of the surface part in the basic shape of the transmitted part,
A large number of convex portions (for example, convex portions having an inclined surface in the circumferential direction) are provided on one of the transmitting portion and the transmitted portion, and a large number of convex portions or concave portions (for example, concave portions having an inclined surface in the circumferential direction) on the other side. )
At a load less than the set torque, the axial position of the transmitting portion and the transmitted portion is maintained within a predetermined range by the axial urging force, and the required amount is obtained by engagement between the convex portions or the convex portion and the concave portion. The state where the rotational force can be transmitted is maintained,
When a load greater than the set torque is applied, the convex portions of the two or the convex portions and the concave portions separate the transmitting portion and the transmitted portion in the axial direction relative to the predetermined range against the urging force. The meshing is released or insufficient and transmission of the required rotational force is interrupted;
A wave-shaped portion having a predetermined central angle as a period and an amplitude in the axial direction (wave shape traveling in the circumferential direction) at least in an annular portion having a predetermined radial width centered on the rotational axis in both the transmitting portion and the transmitted portion Part, preferably the amplitude does not change in the radial direction)
When the load is less than the set torque, the axial position of the transmitting portion and the transmitted portion is maintained within a predetermined range by the urging force in the axial direction, and the required rotational force is transmitted by the meshing of the two corrugated portions. State that can be done,
When a load greater than the set torque is applied, both the wave-shaped portions resist the urging force and the transmitting portion and the transmitted portion are separated from each other in the axial direction relative to a predetermined range, and the meshing is performed. Although it is cancelled | released or it becomes inadequate, what can interrupt transmission of a required rotational force can be mentioned, but it is not restricted to these.

As the wave shape portion, for example,
In the circumferential direction, it has a triangular wave shape, curved wave shape (typically a sine wave shape, for example), or a sawtooth waveform, and when the load exceeding the set torque is applied, the meshing between the transmitting part and the transmitted part is released and recovered. Although what is performed smoothly can be mentioned, it is not restricted to these.

  The set torque can be substantially constant regardless of the direction of rotation, and different torques can be set according to the direction of rotation.

  In order to set a substantially constant torque regardless of the direction of rotation, for example, the angle of contact between the convex portions of the transmission portion and the transmitted portion or the contact angle between the convex portion and the concave portion or the corrugated portions is the direction of rotation. Regardless of whether it is constant or not. For example, an isosceles triangular waveform having a triangular waveform or a sinusoidal curved waveform.

  In order to set different torques depending on the direction of rotation, for example, the angle between the convex portions of the transmitting portion and the transmitted portion or the contact angle between the convex portion and the concave portion or the corrugated portion depends on the rotational direction. It may be different. For example, if the angle with respect to the plane orthogonal to the rotation axis is reduced, the set torque can be reduced, and if the angle is increased, the set torque can be increased.

A Rotational force transmission device D Drive rotation part D1 Transmission part D2 Base end part D3 Shaft part D4 Diameter expansion tip part Dw Waveform part M Electric motor M1 Output shaft N Driven rotation part N1 Transmitted part N2 Cylindrical base part N3 Arm for output Part Nw Waveform part P Pin S Compression coil spring

Claims (9)

A device for transmitting a rotational force by a transmission part of a drive rotation part and a transmitted part of a driven rotation part,
The transmitting portion and the transmitted portion are opposed to each other in the axial direction, and an axial force in a direction to separate in the axial direction is transmitted between the transmitting portion and the transmitted portion in accordance with the transmission of the rotational force around the axial direction. Can occur,
The transmitting part and the transmitted part may move relatively in the axial direction between a mutual position where the required rotational force can be transmitted and a mutual position where the required rotational force cannot be transmitted,
One or both of the drive rotation unit and the driven rotation unit are applied with an urging force facing each other in the axial direction.
In a load less than the set torque, a state in which a required rotational force can be transmitted between the transmission unit and the transmitted unit by the urging force in the axial direction is maintained.
When a load greater than a set torque is applied, the transmission of the required rotational force is interrupted by the movement of the transmitting part and the transmitted part in a direction that is relatively separated in the axial direction against the urging force, When the load returns to less than a set torque, a state where a required rotational force can be transmitted between the transmission unit and the transmitted unit is recovered. Waveform portions each having an amplitude in the axial direction with a predetermined center angle as a period are provided in annular portions having a predetermined radial direction centered on at least the rotation axis in both the transmitting portion and the transmitted portion,
When the load is less than the set torque, the axial position of the transmitting portion and the transmitted portion is maintained within a predetermined range by the axial urging force, and the required rotational force is transmitted by the meshing of the corrugated portions. State that can be done,
When a load greater than the set torque is applied, both the wave-shaped portions resist the urging force and the transmitting portion and the transmitted portion are separated from each other in the axial direction relative to a predetermined range, and the meshing is performed. 2. The rotational force transmitting device according to claim 1, wherein transmission of a required rotational force is interrupted due to being released or insufficient. A large number of convex portions are provided on one of the transmission portion and the transmitted portion, and a large number of convex portions or concave portions are provided on the other side.
When the load is less than the set torque, the axial directional force between the transmitting portion and the transmitted portion is maintained within a predetermined range by the above-described axial urging force, and the required amount is obtained by engaging both convex portions or convex portions and concave portions. The state where the rotational force can be transmitted is maintained,
When a load greater than the set torque is applied, the convex portions of the two or the convex portions and the concave portions separate the transmitting portion and the transmitted portion in the axial direction relative to the predetermined range against the urging force. 2. The rotational force transmission device according to claim 1, wherein the meshing is released or insufficient, and transmission of a required rotational force is interrupted.   The torque transmission device according to any one of claims 1 to 3, wherein the transmission unit of the drive rotation unit and the transmission unit of the driven rotation unit are coaxial.   The other rotating part is coaxially fitted on the rotating part of either the driving rotating part or the driven rotating part so as to be relatively rotatable, and a required rotational force can be transmitted between the transmitting part and the transmitted part. The drive rotation unit and the driven rotation unit can move relatively in the axial direction between the position and the mutual position where the required rotational force cannot be transmitted, and the transmission unit is connected to one or both of the drive rotation unit and the driven rotation unit. 5. The rotational force transmitting device according to claim 4, wherein urging forces facing each other in the axial direction are applied so that a required rotational force can be transmitted between the transmitting portion and the transmitted portion.   The drive rotation unit and the driven rotation unit are rotatably fitted coaxially to the non-rotating shaft body, and the mutual position where the required rotation force can be transmitted between the transmission unit and the transmitted unit and the required rotation force are The drive rotation unit and the driven rotation unit can move relatively in the axial direction between the mutual positions that cannot be transmitted, and one or both of the drive rotation unit and the driven rotation unit are between the transmission unit and the transmitted unit. 5. The rotational force transmitting device according to claim 4, wherein biasing forces in directions facing each other in the axial direction are applied so that a required rotational force can be transmitted.   The rotational force transmission device according to any one of claims 1 to 6, wherein an output arm-like portion having a radially outward component is provided in the driven rotation portion.   The torque transmission device according to any one of claims 1 to 7, wherein the set torque is substantially constant regardless of the direction of rotation.   The rotational force transmission device according to any one of claims 1 to 8, wherein the urging force in the axial direction is an elastic urging force by an elastic body.