JPH0792107B2 - Torque limiter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to transmission of rotational torque,
The present invention relates to a torque limiter that cuts off.

[0002]

2. Description of the Related Art As the torque limiter, a coil spring type using a coil spring and a friction plate type using a friction plate have been conventionally known.

[0003]

By the way, in the coil spring type torque limiter, the on / off torque can be generated only in the rotation in one direction, and the on / off torque cannot be generated in the rotation in the opposite direction.

On the other hand, in the friction plate type torque limiter, on / off torque can be generated in both forward and reverse rotations, but the same torque is generated in both directions, and different torques are generated for both rotations. I can't.

Generally, in a copying machine, the document pressing cover is allowed to rotate smoothly in the opening direction and is slowly rotated in the closing direction to prevent abrupt closing. It is necessary to give a small torque to the lid for rotation in the opening direction and a large torque for rotation in the closing direction.

By the way, in the conventionally known torque limiter, as described above, the on / off torque is transmitted only in one direction rotation, or the same amount of on / off torque is transmitted in both direction rotation. Therefore, the above-mentioned movement cannot be applied to the pressing lid by the torque limiter alone, and two torque limiters having different torque transmission directions and torque magnitudes and a one-way clutch for switching the rotation of the shaft are provided. There is a problem that the opening and closing mechanism of the upper lid becomes complicated because it is necessary to use the above in combination.

An object of the present invention is to provide a torque limiter having an extremely simple structure capable of transmitting torques of different magnitudes to normal and reverse rotations.

[0008]

In order to solve the above-mentioned problems, the present invention has an inner ring provided outside the shaft and an outer ring provided outside the inner ring. Is provided with a plurality of inclined surfaces that incline in the circumferential direction at required intervals in the circumferential direction, and rollers are installed between each inclined surface and the cylindrical outer surface of the inner ring. A torque setting spring that pushes in the direction of biting into the outer surface is provided, a spring accommodating hole is formed in the inner diameter surface of the inner ring, and a coil spring that binds the shaft is accommodated in the spring accommodating hole, and one end of the coil spring is inserted into the inner ring. It adopted the configuration connected to.

[0009]

The torque limiter having the above structure transmits the rotation of the shaft in the direction in which the coil spring is wound up to the inner ring via the coil spring, and the inner ring via the roller incorporated between the inner ring and the outer ring. The rotation of is transmitted to the outer ring. During the transmission of the torque, slippage occurs between the inner ring and the roller in a state where the force of the inner ring pushing the roller and the torque setting spring force are balanced, and the transmission of the torque to the outer ring is interrupted.

Further, when the shaft rotates in the opposite direction, the diameter of the coil spring is expanded by the rotation of the shaft, and the binding force for tightening the coil spring and the rotation transmitted from the coil spring to the inner ring.
Rotate the shaft from the inner ring to the outer ring until the torque is balanced.
, Where the binding force and rotational torque are balanced ,
Only the shaft idles by causing a slip between the shaft and the coil spring.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIGS. 1 and 2, a roller type torque limiter mechanism 3 is incorporated between the outer ring 1 and the inner ring 2.

The torque limiter mechanism 3 is provided with a plurality of inclined surfaces 5 inclined in the circumferential direction on the inner diameter surface of the outer ring 1 at predetermined intervals in the same direction, and is assembled between the outer ring 1 and the inner ring 2 for holding. A pocket 7 is formed on the container 6 so as to face the inclined surface 5,
The roller 8 assembled in the pocket 7 is pressed by the torque setting spring 9 in a direction to bite into the inclined surface 5 and the cylindrical outer surface of the inner ring 2.

An assembly composed of an outer ring 1, an inner ring 2 and a roller type torque limiter mechanism 3 is incorporated in a storage space 11 of a rotary body 10 made of a synthetic resin molded on the outer side of the outer ring 1, and an inner diameter of the storage space 11 is incorporated. The axial projection 12 formed on the surface is engaged with the axial groove 13 provided on the outer diameter surface of the outer ring 1 to relatively prevent the rotating body 10 and the outer ring 1 from rotating.

A lid 1 is provided inside the opening of the storage space 11.
4 is provided, and its lid 14 prevents the outer ring 1 and the retainer 6 from slipping out in the axial direction.

In the illustrated example, the rotating body 10 is a roller, but the rotating body 10 is not limited to this and may be, for example, a sprocket, a gear, or a pulley.

A spring accommodating hole 15 is formed in the inner diameter surface of the inner ring 2, and a coil spring 16 is incorporated in the spring accommodating hole 15. The coil spring 16 is wound in the same direction as the roller 8 of the torque limiter mechanism 3 moves toward the inclined surface 5 and the cylindrical outer surface of the inner ring 2.

The coil spring 16 is attached to the outer side of a shaft 17 which is inserted in the inner ring 1 in the expanded state,
One end thereof is connected to the inner ring 2.

When the coil spring 16 and the inner ring 2 are connected to each other, in FIG.
8a is provided, and the bent piece 18a is made to engage with the axial engaging groove 19 formed on the inner diameter surface of the spring accommodating hole 15. However, as shown in FIG. It is also possible to provide a bent piece 18b in the axial direction and engage the bent piece 18b with the notch 20 provided at the closed end of the spring housing hole 15.

In the torque limiter having the above-mentioned structure, when the shaft 17 is rotated in the direction of arrow A in FIG. 2, the coil spring 16 is wound and the diameter is reduced, and the shaft 17 is rotated through the coil spring 16. It is transmitted to the inner ring 2. Also, the inner ring 2
Is transmitted to the outer ring 1 via the roller 8 of the roller type torque limiter mechanism 3.

When the rotational torque is transmitted as described above, the inner ring 2
When the rotational torque from the outer ring 1 to the outer ring 1 becomes larger than the set spring force of the torque setting spring 9, the roller 8 is formed between the inclined surface 5 and the cylindrical outer surface of the inner ring 2 against the elasticity of the torque setting spring 9. It moves toward the wide portion of the space, slippage occurs between the inner ring 2 and the roller 8, and the transmission of rotational torque to the outer ring 1 is blocked.

When the shaft 17 rotates in the direction of arrow B,
Since the coil spring 16 is unwound, the binding force for the coil spring 16 to tighten the shaft 17 is weakened, and the binding force and the coil
Sliding occurs where the rotational torque transmitted from the spring 16 to the inner ring 2 is balanced, and the shaft 17 idles. Since the shaft 17 and the inner ring 2 rotate relative to each other during the idling, it is preferable that the inner ring 2 be made of a sintered oil-impregnated metal to enhance the lubricity between the inner ring 2 and the shaft 17.

In this way, when the shaft 17 rotates in the direction of arrow A, on / off torque is generated by the spring force of the torque setting spring 9, and when rotating in the opposite direction, the coil spring 16 is rotated.
Generates on / off torque by the tightening force that tightens the shaft 17, so that by making the spring force of the torque setting spring 9 and the tightening force of the coil spring 16 different, different magnitudes can be obtained in the forward and reverse rotation directions. Torque can be transmitted.

[0023]

As described above, in the torque limiter according to the present invention, different magnitudes of torque can be transmitted with respect to forward and reverse rotations, and the number of parts is simple, so that the manufacturing cost is reduced. Can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of a torque limiter according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a vertical sectional front view showing another embodiment of the torque limiter.

[Explanation of symbols]

 1 Outer ring 2 Inner ring 5 Inclined surface 7 Pocket 8 Roller 9 Torque setting spring 15 Spring housing hole 16 Coil spring 17 Shaft

Claims (1)

[Claims] 1. An inner ring provided on the outer side of a shaft and an outer ring provided on the outer side of the inner ring, wherein a plurality of inclined surfaces inclined in the circumferential direction are provided on an inner diameter surface of the outer ring at predetermined intervals in the circumferential direction. , A roller is installed between each inclined surface and the cylindrical outer surface of the inner ring, and a torque setting spring that presses each roller in a direction to bite into the inclined surface and the cylindrical outer surface of the inner ring is provided. a spring receiving hole is formed in the in the spring accommodating hole
A torque limiter that houses a coil spring that binds the shaft tightly and connects one end of the coil spring to the inner ring.