JPH053655U - Torque limiter - Google Patents

Abstract

(57) [Summary] [Purpose] There is little variation in torque value, and grease leakage can be prevented. A coil spring 12 is tightly fitted to an inner ring 11 housed in a housing 10, one end of the coil spring 12 is engaged with the housing 10, and the rotation of the inner ring 11 is transmitted to the housing 10 via the coil spring 12. At the same time, when the load on the housing 10 exceeds a certain value, slippage occurs between the inner ring 11 and the coil spring 12 to interrupt the transmission of rotational torque.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to a torque limiter used for a paper feeding device and a braking device in office equipment and the like.

[0002]

[Prior Art]

 As shown in FIG. 2, a torque limiter that has been conventionally used in office equipment has an input disk 1 and an output disk 2 butted against each other coaxially, and one coil is provided on the outer diameter surface of both disks 1 and 2. The spring 3 is an interference fit, and a protective cover 4 is placed on the outside of the coil spring 3 so as to fit over both the disks 1 and 2.

The outer diameter d ₁ of the spring fitting portion of the output disc 2 is formed to be slightly larger than the inner diameter d of the coil spring 3. Further, the outer diameter d ₂ of the input disk 1 is formed to be slightly larger than the outer diameter d ₁ of the output disk 2. Therefore, the binding force of the coil spring 3 is stronger on the input disk 1 side than on the output disk 2 side.

In the above torque limiter, assuming that the winding direction of the coil spring 3 is right-handed and the input disc 1 rotates right while the output disc 2 is fixed, The coil spring 3 slides with the output disk 2 due to the difference in the binding force applied to the disks 1 and 2.

The torque required to cause this slip is determined by the binding force of the coil spring 3, the diameter of the sliding portion, and the friction coefficient of that portion.

In actual use, the input member is connected to the input disc 1, the output member is connected to the output disc 2, and the torque applied to the input member is transferred to the input disc 1, the coil spring 3, It is transmitted to the output member via the output disk 2. At this time, it is important that the minimum value of the torque that causes slippage of the coil spring 3 with respect to the output disk 2, that is, the torque value is stable.

[0007]

[Problems to be solved by the device]

 The inner diameter d of the coil spring 3 used in the above-mentioned torque limiter usually has a large variation, and it is difficult to prepare a large number of inexpensive and inexpensive variations.

However, since the above-described conventional torque limiter has a structure in which the coil spring 3 is fitted over the input disk 1 and the output disk 2, the entire length of the coil spring 3 actually causes torque. Therefore, there is a problem that the torque value tends to fluctuate, and the total length of the spring tends to increase for the torque.

Further, in order to prevent the occurrence of wear due to the slippage of the coil spring 3 and the output disc 2, the internal space covered by the protective cover 4 is filled with grease. However, the input disc 1 and the output disc 2 are filled with grease. It is difficult to hold the grease because a gap is apt to occur at a portion where the two are abutted with each other, a fitting portion between the disks 1 and 2 and the protective cover 4, and the like.

Further, when the input disk 1 and the output disk 2 are displaced in the radial direction during assembly into a machine, this causes a change in the contact length between the output disk 2 and the coil spring 3, resulting in a torque value. It causes a change.

Therefore, an object of the present invention is to provide a torque limiter in which the torque value can be stabilized by using the entire length of the coil spring as a sliding surface and the grease can be surely filled.

[0012]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention stores an inner member inside an outer member, and tightly fits a coil spring around the inner member. , The one end of which is engaged with the outer member.

[0013]

[Action]

 When the inner member is rotated in the tightening direction of the coil spring, the coil spring locks the inner member and the outer member, but when the inner member is rotated in the loosening direction of the coil spring, the coil spring slips. In the non-existence range, torque is transmitted through the coil spring and the outer member. When the magnitude of the torque applied to the outer member exceeds a certain value, the coil spring slips, interrupting the torque transmission.

[0014]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. 1 of the accompanying drawings.

As shown in FIG. 1, the torque limiter of the embodiment includes a housing 10 as an outer member, an inner ring 11 as an inner member, a coil spring 12, and a lid member 13 attached to an open end of the housing 10. Composed.

The housing 10 is provided with a slide bearing portion 14 having a larger diameter on the inner diameter surface, and a spring accommodating portion 15 having a diameter larger than that of the bearing portion 14.

The coil spring 12 is accommodated in the spring accommodating portion 15 with a slight clearance from the inner diameter surface thereof. The coil spring 12 is composed of a wire material having a quadrangular cross section, and is a compression coil spring that has a gap between the wire materials in an unloaded state and generates elasticity by compression.

A fitting groove 16 is formed on the inner diameter surface of the end portion of the spring housing portion 15, and the lid member 13 is forcibly fitted into the fitting groove 16 to bend the end portion of the coil spring 12 in the axial direction. By engaging the engaging hook 17 formed as described above with the recess of the lid member 13, the coil spring 12 and the housing 10 are coupled in the rotational direction.

The inner ring 11 is inserted into the inside of the lid member 13 and the coil spring 12 and is rotatably supported by the bearing portion 14 and the inner diameter surface of the lid member 13, and the outer diameter D of the inner ring 11 is equal to that of the coil spring 12. The diameter of the coil spring 12 is slightly larger than the inner diameter D ₁ of the coil spring 12, and the coil spring 12 is tightly fitted around the inner ring 11.

The spring accommodating portion 15 of the housing 11 is sealed by fitting the inner ring 11 and closing the lid member 13, and the interior thereof is filled with grease.

The torque limiter of the embodiment is configured as described above, and when the inner ring 11 is rotated by the input member 18 with the input member 18 connected to the inner ring 11 and the output member 19 connected to the housing 10, When the rotation is transmitted to the output member 19 via the coil spring 12 and the housing 10 and the load of the output member 19 exceeds a certain value, slippage occurs between the inner ring 11 and the coil spring 12 and the torque transmission is interrupted. ..

The bearing portion 14 of the housing 10 and the inner diameter portion of the lid member 13 can receive a radial load applied to the inner ring 11.

[0023]

【effect】

 As described above, according to the present invention, since the entire inner diameter of the coil spring is used for the sliding portion for generating torque, the variation in the inner diameter of the coil spring in the axial direction is alleviated and the fluctuation of the torque value is reduced. You can

Since the inner member is housed inside the outer member and the coil spring tightly fitted to the inner member is housed between the inner member and the outer member, a gap is generated in the coil spring housing space. Is only the part that receives the radial load, which is advantageous for preventing leakage of the grease filled in the coil spring storage space.

Further, since the entire inner diameter of the coil spring tightly fitted to the inner member is used for the sliding portion for generating torque, even if the inner member slightly moves in the axial direction, the torque value Does not change.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view showing a conventional torque limiter.

[Explanation of symbols]

 10 Housing 12 Coil Spring 13 Lid Member 14 Bearing 15 Spring Storage 17 Engagement Hook

Claims (1)

[Claims for utility model registration] [Claim 1] An inner member is housed inside an outer member, a coil spring is interference-fitted around the inner member, and one end of the inner member is engaged with the outer member. Torque limiter.