JPH08270673A - Torque limiter - Google Patents

Abstract

PURPOSE: To stabilize torque at the initial stage of rotation of a torque limiter employing a coil spring. CONSTITUTION: A coils spring 3 is incorporated between an inner ring 1 and an outer ring 2 rotatably located at the outside thereof and a small coil part 3a to fasten the outside diameter surface of the inner ring 1 is arranged at the roil spring 3. One of bent pieces 4 and 5 formed at the two ends of the coil spring 3 is coupled to the outer ring 2 and the other bent piece 5 is coupled to an adjustment ring 6 pressed in the opening end part of the outer ring 2. The inner ring 1 is formed of a sintered substance, the inner ring 1 is impregnated with a lubricant, and through lubrication of a contact part between the inner ring 1 and the small coil part 3a by effusion of a lubricant, initial torque is stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter for transmitting and blocking rotational torque.

[0002]

2. Description of the Related Art As a torque limiter of this type, the one shown in FIG. 4 has been conventionally known. This torque limiter incorporates a coil spring 13 between an inner ring 11 and an outer ring 12 rotatably provided on the outer side of the inner ring 11, and a small diameter coil portion 13a for tightening an outer diameter surface of the inner ring 11 on the coil spring 13.
One of the bent pieces 14, 15 formed at both ends of the coil spring 13 is connected to the closed end of the outer ring 12, and the other bent piece 15 is rotatably press-fitted into the open end of the outer ring 12. It is connected to the adjusting ring 16.

In the above torque limiter, when the inner ring 11 is rotated in the direction opposite to the winding direction of the coil spring 13 when viewed from the adjusting ring 16 side, the inner ring 11 contacts the inner ring 11 and expands to the small diameter coil portion 13a of the coil spring 13. Although a radial force acts, since the bent piece 14 of the small-diameter coil portion 13a is connected to the outer ring 12, the small-diameter coil portion 13a contracts and tightens the inner ring 11.

Therefore, the inner ring 11 is rotated by the coil spring 1.
3 is transmitted to the outer ring 12, and the outer ring 12 rotates in the same direction as the inner ring 11.

When the load on the outer ring 12 increases and the binding force of the small-diameter coil portion 13a of the coil spring 13 for fastening the inner ring 11 becomes smaller than the frictional force at the contact portion between the small-diameter coil portion 13a and the inner ring 11, the inner ring 11 and the small-diameter coil portion 13a. A slip occurs between the outer ring 12 and the outer ring 12, and the transmission of the rotational torque to the outer ring 12 is blocked.

When the inner ring 11 is rotated in the winding direction of the coil spring 13, the small diameter coil portion 13a of the coil spring 13 is rotated.
In contrast to the above, the diameter is increased, slippage occurs between the inner ring 11 and the small-diameter coil portion 13, and the transmission of the rotational torque to the outer ring 12 is blocked.

In the above torque limiter, the number of parts is small, the assembly is easy and the manufacturing cost is low, and when the adjusting ring 16 is rotated with respect to the outer ring 12, the inner diameter of the small diameter coil portion 13a of the coil spring 13 is increased. Has a characteristic that the magnitude of the torque that can be transmitted from the inner ring 11 to the outer ring 12 can be adjusted.

[0008]

In the above torque limiter, when the torque transmission is cut off, the inner ring 11 rotates in contact with the small-diameter coil portion 13a, so that the contact portion between the inner ring 11 and the small-diameter coil portion 13a is abraded. In order to prevent the wear of the inner ring 11 and the small-diameter coil portion 13a, the contact portion between the inner ring 11 and the small-diameter coil portion 13a is lubricated with grease. Here, since the grease is sealed inside the outer ring 12, when the torque limiter is rotated at a high speed, the torque fluctuation is large at the initial stage of rotation, and there are some points to be improved in improving the torque accuracy. .

That is, when the inner ring 11 is rotated while the outer ring 12 of the torque limiter shown in FIG. 4 is filled with grease and the outer ring 12 is stopped to measure the torque of the inner ring 11, it is shown in FIG. The test result was obtained.

[0010] Here, No. 1 is the inner ring 11 640rpm
The torque measurement result when rotated at is shown.
2 shows the torque measurement result when the inner ring 11 is rotated at 1000 rpm. In any case, 0.2 seconds operation,
The operation was performed in a pattern of stopping for 0.3 seconds.

As is clear from the above test results, an increase in initial torque occurs in the torque limiter filled with grease. It is considered that the reason is that the grease is agitated in the initial stage of rotation of the inner ring 11 and thus becomes a rotation resistance, and the grease becomes familiar with the passage of time.

As described above, if the torque fluctuates in the initial stage of rotation, the rotation of the inner ring may not be transmitted to the outer ring in the initial stage of rotation of the inner ring.

An object of the present invention is to stabilize the initial torque of a torque limiter using a coil spring.

[0014]

In order to solve the above problems, in the present invention, a coil spring is incorporated between an inner ring and an outer ring, and a small diameter coil portion for tightening the outer diameter surface of the inner ring is attached to the coil spring. In the provided torque limiter, the inner ring is formed of a sintered body, and the inner ring is impregnated with a lubricant.

Here, examples of the lubricant include grease and lubricating oil.

[0016]

As described above, by impregnating the inner ring made of the sintered body with the lubricant, the lubricant exudes to the outer diameter surface of the inner ring when the torque limiter is operated, and the contact portion between the inner ring and the small diameter coil portion Lubricate. Therefore, the lubricant is not agitated, and stable torque can be generated from the start of operation.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a first embodiment of the present invention.
The torque limiter in this embodiment includes an inner ring 1, an outer ring 2 rotatably provided on the inner ring 1, and a coil spring 3 incorporated between the two wheels 1, 2 as in the conventional example described above. The coil spring 3 is provided with a small-diameter coil portion 3a that tightens the outer diameter surface of the inner ring 1 and a large-diameter coil portion 3b that is not in contact with both wheels 1 and 2.

A bending piece 4 is provided at the end of the small-diameter coil portion 3a, and the bending piece 4 is connected to the closed end of the outer ring 2. On the other hand, a bent piece 5 is provided at the end of the large-diameter coil portion 3b, and the bent piece 5 is connected to an adjusting ring 6 rotatably press-fitted into the open end of the outer ring 2.

The inner ring 1 is made of a sintered body of metal powder,
The inside is impregnated with a lubricant. The lubricant may be lubricating oil or grease.

The inner ring 1 has a surface roughness Ra of about 0.6 to 1.0 in order to facilitate the exudation of the lubricant.

The operation of the torque limiter having the above structure is the same as the operation of the torque limiter shown in FIG.

As shown in the first embodiment, the inner ring 1 is made of a sintered body and impregnated with the lubricant, so that the lubricant oozes to the outer diameter surface of the inner ring 1 during the operation of the torque limiter. The lubricant lubricates the contact portion between the inner ring 1 and the small-diameter coil portion 3a.

As described above, by lubricating the contact portion between the inner ring 1 and the small-diameter coil portion 3a with the lubricant impregnated in the inner ring 1, the lubricant is not agitated, and the inner ring 1 rotates from the initial stage of rotation. Since the resistance is constant, the initial torque can be stabilized.

Incidentally, when the outer ring 2 of the torque limiter shown in FIG. 1 was stopped and the inner ring 1 impregnated with lubricating oil was rotated at a high speed to measure the torque of the inner ring 1, the results shown in FIG. 3 were obtained.

Here, the measurement condition is that the number of rotations of the inner ring 1 is 1
The test was carried out at an operating pattern of 000 rpm for 0.2 second operation and 0.3 second stop.

As is clear from the above results, it can be understood that there is no change in torque from the start of operation and the torque is stable from the initial stage of rotation.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, a round spring made of a round wire is used as the coil spring 3, and the small-diameter coil portion 3 of the coil spring 3 is used.
A space is provided on the spiral rod of a.

By using the coil spring 3 as described above, the contact area between the small diameter coil portion 3a and the inner ring 1 is small,
Lubricating oil that has exuded between the spiral parts is used for the small diameter coil part 3a and the inner ring 1.
It becomes easy to invade between the contact portions of the inner ring 1, and the contact portion between the small diameter coil portion 3a and the inner ring 1 can be satisfactorily lubricated.

In the torque limiter of the above embodiment, the outer ring 2 is stopped and the inner ring 1 is rotated at a high speed to rotate the inner ring 1
When the torque was measured, it was possible to obtain substantially the same measurement result as in the case shown in FIG. 3, so the description of the measurement result was omitted here.

[0031]

As described above, in the torque limiter according to the present invention, since the inner ring is made of a sintered body and the inner ring is impregnated with the lubricant, the lubricant exuding on the outer diameter surface of the inner ring is used. The contact portion between the inner ring and the coil spring can be lubricated. Therefore, the lubricant is not agitated, and the initial torque at the start of operation can be stabilized.

By using grease as the lubricant, the oil content of the grease gradually exudes to the inner ring surface,
The lubricant is retained well and the lubrication life can be improved.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a second embodiment of the torque limiter according to the present invention.

FIG. 3 is a graph showing a torque measurement result of an inner ring in the same torque limiter.

FIG. 4 is a sectional view showing a conventional torque limiter.

FIG. 5 is a graph showing torque measurement results of the inner ring in the conventional torque limiter.

[Explanation of symbols]

 1 Inner ring 2 Outer ring 3 Coil spring 3a Small diameter coil section 4, 5 Bending piece 6 Adjustment ring

Claims (2)

[Claims] 1. An outer ring is rotatably provided on the outer side of an inner ring, a coil spring incorporated between the two rings is provided with a small diameter coil portion for tightening an outer diameter surface of the inner ring, and a folding formed at both ends of the coil spring. In a torque limiter in which one of the bending pieces is connected to the outer ring and the other bending piece is connected to an adjusting ring that is rotatably press-fitted into the open end of the outer ring, the inner ring is formed of a sintered body and the inner ring is lubricated. A torque limiter characterized by being impregnated with a chemical. 2. The torque limiter according to claim 1, wherein the lubricant is one of grease and lubricating oil.