JPS6352263B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to devices such as tape recorders that rotate a driven body, such as a take-up reel stand, by rotating a motor in forward and reverse directions to wind up a magnetic tape. The present invention relates to a rotary power transmission device that is effective in use.

In conventional rotary power transmission devices of this kind, for example, methods that utilize a combination of friction plates and springs, or permanent magnets and hysteresis materials, torque loss occurs due to the friction plates and hysteresis materials while the rotationally driven body is being driven to rotate. Due to the structure, it was not possible to eliminate this torque loss. For this reason, the drive motor requires more torque than necessary (torque loss), and a large amount of motor current must be passed through the drive motor.

The present invention solves the above-mentioned conventional problems, has a structure in which almost no torque loss occurs while rotating the rotationally driven body, has a small number of components, has a simple component configuration, and transfers the power of the motor to the motor. It is an object of the present invention to provide a rotational power transmission device that can reliably transmit power to a desired rotationally driven body according to the rotational direction.

The present invention will be explained below using an example in which the present invention is applied to a video tape recorder.

1 and 2 are plan views of essential parts in various states of an embodiment of the present invention, and FIG. 3 is a sectional view of the essential parts. In those drawings, a motor 1 capable of forward and reverse rotation is fixed to a substrate 2. The main rotating body 3 is press-fitted into the motor shaft 4 and rotates integrally with the motor shaft 4. The first unidirectional clutch mechanism 5 is fitted onto the motor shaft 4 and is fixed to the first rotating body 6. When the motor shaft 4 rotates in the forward direction (hereinafter referred to as clockwise direction), the first rotating body 6 is rotated in the clockwise direction by the first unidirectional clutch mechanism 5; For rotation (referred to as clockwise), the first rotating body 6 is connected to the motor shaft 4 by the first unidirectional clutch mechanism 5.
It does not rotate because it does not receive any rotational force. The second unidirectional clutch mechanism 7 is fitted onto the motor shaft 4 and fixed to the second rotating body 8. When the motor shaft 4 is rotating counterclockwise, the second unidirectional clutch mechanism 7 causes the second rotating body 8 to rotate.
rotates counterclockwise, but when the motor shaft 4 is rotating clockwise, the second rotating body 8 is not subject to the rotational force of the motor shaft 4 due to the second unidirectional clutch mechanism 7, so that it does not rotate. do not. The rotating member 9 is rotatably loosely fitted onto the motor shaft 4, and a rotation transmitting member 11 is rotatably provided on a shaft 10 implanted at one end thereof. A coiled compression spring 14 is stretched between a convex portion 12 provided on a part of the rotating member 9 and a convex portion 13 provided on the substrate 2.

A first reel stand 15 and a second reel stand 16, which are rotationally driven bodies, are rotatably provided on shafts 17 and 18, respectively, which are implanted in the substrate 2. When the rotating member 9 rotates to the position shown in FIG. 1 or FIG. reel stand 15 or second reel stand 1
The rotational driving force of the motor shaft 4 is transmitted to the first reel stand 15 or the second reel stand 16. A shaft 19 provided at the other end of the rotating member
An arm 20 is rotatably provided. A first locking portion 20 provided integrally with the arm 20
a and the second locking portion 20b are connected to the first rotating body 6
and engages with or separates from the convex portions 21 and 22 of the second rotating body 8, respectively.

In FIG. 1, when the motor shaft 4 rotates clockwise, the first unidirectional clutch mechanism 5
The first rotating body 6 rotates clockwise integrally with the motor shaft 4.

However, since the convex portion 21 of the first rotating body 6 is locked by the first locking portion 20a, the first
The first locking portion 2 is rotated by the rotation torque of the rotating body 6.
A clockwise force centered on the motor shaft 4 is applied to 0a. On the other hand, the first locking part 20a is installed on the rotating member 9 via the shaft 19, and since the rotating member 9 is installed rotatably around the motor shaft 4, the first locking part 20a Due to the force applied to the locking portion 20a, the rotating member 9 begins to rotate clockwise together with the first rotating body 6 and the arm 20 against the biasing force of the compression spring 14.

Shafts 23 and 24 are implanted in the base plate 2, and when the rotating member 9 moves from the position shown in FIG. 1 to the position shown in FIG. As the rotating member 9 moves further due to the biasing force, the engagement between the first locking portion 20a and the convex portion 21 is released, and the second locking portion 20b and the convex portion 2 are disengaged from each other.
The arm 20 is rotated to a position where the arms 2 are engaged.

In FIG. 2, when the motor shaft 4 rotates counterclockwise, the second unidirectional clutch mechanism 7 causes the second rotating body 8 to rotate counterclockwise integrally with the motor shaft 4.

However, since the convex portion 22 of the second rotating body 8 is locked by the second locking portion 20b, the second
Due to the rotational torque of the rotating body 8, a counterclockwise force about the motor shaft 4 is applied to the second locking portion 20b. On the other hand, the second locking part 20b is installed on the rotating member 9 via the shaft 19, and since the rotating member 9 is installed rotatably around the motor shaft 4, the second locking part 20b Due to the force applied to the locking portion 20b, the rotating member 9 rotates counterclockwise together with the second rotating body 8 and the arm 20 against the biasing force of the compression spring 14. Start. When the rotating member 9 moves from the position shown in FIG. 2 to the position shown in FIG.
When the rotating member 9 is further moved by the urging force of 4, the engagement between the second locking part 20b and the convex part 22 is released, and the first locking part 20a and the convex part 21 are disengaged. The arm 20 rotates to the engaging position. Arm 20, first locking part 20a, second locking part 20
b, the shaft 19, the protrusions 21 and 22, and the shafts 23 and 24 constitute a locking means.

Next, the operation of this embodiment will be explained step by step.

1 and 3, when the motor shaft 4 rotates clockwise, the main rotating body 3 also rotates clockwise, and the first rotating body 6 is also rotated clockwise by the first unidirectional clutch mechanism 5. However, the second rotating body 8 is not rotated by the second unidirectional clutch mechanism 7. When the first rotating body 6 rotates clockwise,
Since the convex portion 21 and the first locking portion 20a are engaged and the arm 20 is on the rotating member 9, the rotating member 9 receives a clockwise rotational force from the rotational force of the motor shaft 4. It begins to rotate clockwise. At this time, the rotating member 9 is receiving a counterclockwise rotating force due to the elastic force of the compression spring 14. The rotating member 9 overcomes this elastic force and rotates clockwise, so that the protrusion 12 provided on the rotating member 9 forms a straight line connecting the motor shaft 4 and the protrusion 13 provided on the base plate 2. When located on the right side, the rotation member 9 receives a clockwise rotation force about the motor shaft 4 due to the elastic force of the compression spring 14.
As the rotating member 9 further rotates clockwise,
When the arm 20 comes into contact with the shaft 24 and further rotates due to the bias of the compression spring 14, the clockwise rotation of the arm 20 is restricted by the shaft 24, so as shown in FIG. The engagement between the first locking portion 20a and the convex portion 21 is disengaged, and the arm 20 moves to a position where the 22nd locking portion 20b and the convex portion 22 are engaged. Due to the elastic force of the compression spring 14, the rotation transmission member 11 is pressed against the first reel stand 15, and the rotational driving force of the motor shaft 4 is transferred to the main rotating body 3 and the rotation transmission member 11.
The signal is transmitted to the first reel stand 15 via the first reel stand 15, and the first reel stand 15 is rotationally driven in the clockwise direction. At this time,
No loss torque is generated in the motor 1 except for rotationally driving the first reel stand 15.

In FIGS. 2 and 3, when the motor shaft 4 rotates counterclockwise, the main rotating body 3 also rotates counterclockwise, and the second rotating body 8 is also rotated counterclockwise by the second unidirectional clutch mechanism 7. Although it rotates clockwise, the first rotating body 6 is not rotated by the first unidirectional clutch mechanism 5. When the second rotating body 8 rotates counterclockwise, the convex portion 22 and the second locking portion 20b engage with each other, and since the arm 20 is on the rotating member 9, the rotating member 9 is attached to the motor shaft. It receives a counterclockwise rotational force from the rotational force of step 4, and begins to rotate counterclockwise. At this time, the rotation member 9 is receiving a clockwise rotation force due to the elastic force of the compression spring 14. The rotating member 9 overcomes this elastic force and rotates counterclockwise, and the convex portion 12 provided on the rotating member 9 rotates against the motor shaft 4.
When located on the left side of the straight line connecting the convex portion 13 provided on the substrate 2, the rotating member 9 receives a counterclockwise rotating force about the motor shaft 4 due to the elastic force of the compression spring 14. As the rotating member 9 further rotates counterclockwise, the arm 20 comes into contact with the shaft 23,
As the arm 20 further rotates due to the urging force of the compression spring 14, the counterclockwise rotation of the arm 20 is restricted by the shaft 23.
The engagement between the locking portion 20b and the projection 22 is disengaged, and the arm 20 moves to a position where the first locking portion 20a and the projection 21 are engaged. Due to the elastic force of the compression spring 14, the rotation transmission member 11 is pressed against the second reel stand 16, and the rotational driving force of the motor shaft 4 is transferred to the second reel stand 1 via the main rotary body 3 and the rotation transmission member 11.
6, and rotates the second reel stand 16 in the counterclockwise direction. At this time, no loss torque is generated in the motor 1 except for rotating the second reel stand 16.

As is clear from the above description, according to the present invention, not only a desired rotationally driven body is rotationally driven according to the rotational direction of the motor, but also there is almost no torque loss while the rotationally driven body is being rotationally driven. , Therefore, it is possible to realize power saving of the motor, miniaturization of the motor, and cost reduction. Furthermore, since the mechanism is simple, the number of component parts can be reduced, and operational reliability can be improved, among other excellent effects.

[Brief explanation of the drawing]

1 and 2 are plan views of essential parts of an embodiment of the present invention in various states, and FIG. 3 is a sectional view of essential parts of the same embodiment. 1... Motor, 2... Board, 3... Main rotating body,
4... Motor shaft, 5... First unidirectional clutch mechanism, 6... First rotating body, 7... Second unidirectional clutch mechanism, 8... Second rotating body, 9... ... rotation member, 11 ... rotation transmission member, 12 ... convex part,
13...Convex portion, 14...Compression spring, 15...First
reel stand, 16... second reel stand, 20...
Arm, 20a...first locking part, 20b...second locking part, 21, 22...convex part.

Claims (1)

[Claims] 1 first and second rotationally driven bodies, and the first
and a main rotary body which is disposed at approximately the same distance from a second rotationally driven body and is capable of forward and reverse rotation; first and second unidirectional clutch mechanisms; A first rotating body that rotates in the same direction as the main rotating body by a unidirectional clutch mechanism; A second rotating body rotates in the same direction as the main rotating body, a rotating member rotatably provided around the rotational axis of the main rotating body, and one end of the rotating member. a first position where the rotation of the main rotating body is transmitted to the first rotationally driven body; and a second position where the rotation of the main rotating body is transmitted to the second rotated body. a rotation transmission member that rotates integrally with the rotation member as the rotation member rotates between the rotation transmission member and the rotation transmission member that urges and holds the rotation transmission member in the first position or the second position. an elastic member, a fixed member, and a rotatably provided rotatable member at the other end of the rotary member;
The rotation transmitting member is in a locking/disengaging relationship with the first rotating body and the second rotating body, and when the rotation transmitting member rotates from the second position to the first position, it comes into contact with the fixed member and the elastic The rotation transmitting member rotates on the rotating member due to the biasing force of the member, locks the rotation of the second rotating body, and releases the rotation lock of the first rotating body, and the rotation transmitting member rotates on the rotating member. By rotationally moving from the first position to the second position, the first rotating body comes into contact with the fixed member and rotates on the rotating member due to the biasing force of the elastic member, thereby stopping the rotation of the first rotating body. A rotary power transmission device comprising a locking means for locking the first rotating body and releasing the rotational lock of the first rotating body.