JPH05126160A - Torque limiter - Google Patents

Abstract

PURPOSE:To obtain a torque limiter adopting a coil spring in which the coil spring terminal fixation method or the coil spring shape manufacturing is easy, assembling is facilitated so that a cost is reduced, and with which operation is ascertained and a torque range is widened. CONSTITUTION:In a torque limiter 10, a coil spring 13 is housed in a spring inserting part 12 of an outer cylindrical member 11 whose one end is opened, and an inner ring 16 is provided in an inner diameter part of the spring 13. A projected inside ring 16 is provided on an inner side of the outer cylindrical member 11. An end diameter of the coil spring 13 is fitted into the ring 16 and fixed thereto. A hook 14 on the other end is engaged with a recession on a cover 17 for closing an opened end between the inner ring 18 and the outer cylindrical member 11. An outer diameter D1 of the inside ring 16 is a little larger than an outer diameter D2 of a tandem part 19 of the inner ring 18, that is, D1>D2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter, and more particularly to a torque limiter used for a paper double feed prevention device, a brake device, etc. in various office equipment.

[0002]

2. Description of the Related Art Generally, a torque limiter transmits a rotational force above a preset torque value in order to protect the drive unit when an overload or impact force is applied to the driven unit for some reason in a rotary shaft system. It is provided at an appropriate position of the shaft system as a means for shutting off. However, the method of using the torque limiter is not limited to such a method, and is also used, for example, in a paper double feed prevention device in various office equipment and the like, a back tensioning brake of a continuous paper drawing portion, and the like.

For example, in a paper double feed prevention device, a torque limiter is provided on one (lower) rotation shaft of a pair of upper and lower paper feed rollers (rubber) for feeding paper, and the torque set value of the torque limiter is exceeded. When both rollers come into contact with each other with torque to feed the paper, and when the paper is superposed, the transmission torque from the roller to the roller decreases, so that the engagement between one roller and its rotating shaft is restored and The rollers are reversed, and the rotation of the rollers in the opposite direction causes the lower side of the overlapped paper to be sent back to the original position, so that the overlapping feed of the paper is prevented by utilizing the torque limiter.

An example of the torque limiter used in this way is shown in FIG. This torque limiter accommodates a coil spring 3 in a spring insertion portion 2 of an outer ring 1 serving as an outer member, and a hook 4 provided at one end of the coil spring 3 is engaged with a recess 6 in an end wall 5 of the outer ring 1. , The hook 4'provided on the other end
Is engaged with a recess 6 ′ of the lid 7 fitted and fixed in the open end of the outer ring 1, and the inner ring 8 serving as an inner member inserted into the coil spring 3 is rotatable by the bearing 9 of the outer ring 1 and the lid 7. The structure is supported by.

The coil spring 3 has a small diameter portion 3a and a large diameter portion 3b, and the inner diameter of the small diameter portion 3a is made equal to or slightly larger than the outer diameter of the inner ring 8 in a natural state.
In this size state, the coil spring 3 is incorporated into the outer ring 1, the inner ring 8 is inserted into the small diameter portion 3a, the lid 8 is fitted and the hook 4'and the recess 9 are engaged, and the lid 7 is rotated in this state. By moving and twisting the coil spring 3 in the winding direction, the small diameter portion 3a
Is contracted to the inner ring 8 in a tightly fitted state, and a tight binding force is applied to the inner ring 8 in the radial direction. In the above torque limiter, when the inner ring 8 is rotated in the direction opposite to the winding direction of the coil spring 3, the rotation is transmitted to the outer ring 1 through the coil spring 3, and at this time, the inner ring 8 and the small diameter portion 3a slide. The minimum value of the torque that causes is the torque value.
Can be adjusted by rotating the coil spring 3 to change the twist amount of the coil spring 3.

[0006]

However, the coil spring of the conventional torque limiter described above has two diameter portions, the diameter portion having a small diameter portion and the diameter portion having a large diameter. Therefore, in manufacturing the coil spring, these different diameter portions are used. Is troublesome, laborious, and expensive.

Further, since the torque value to be set is determined by the small diameter portion, the diameter of the portion for generating the torque is small, which may be inappropriate when a large set torque is required.

In the present invention, in consideration of the problems of the above-mentioned conventional torque limiter, the coil spring has a substantially constant overall length diameter, is easy to manufacture, and is easy to fix and assemble the terminal to reduce the cost. Another object of the present invention is to provide a torque limiter that operates reliably and expands the range of set torque.

[0009]

In order to solve the above problems, the present invention provides an inner ring having a large-diameter step portion with a large diameter in the central portion of the length of a parallel shaft, and a coil spring wound around the outer periphery thereof. It is rotatably fitted into an outer cylinder member that is open at one end and has an inner ring at the back, and the open end between the inner ring and the outer cylinder member is closed with a lid, and the coil springs have the same inner diameter over the entire length. , One end is press-fitted and fixed to the outer diameter of the inner ring, and the other end is provided with a hook to be engaged with the lid, so that the stepped diameter of the different diameter of the inner ring is slightly interference fit or clearance fit slightly smaller than the coil spring inner diameter. Thus, the torque limiter can freely adjust the torque by changing the inner diameter of the coil spring by twisting the lid.

[0010]

In the torque limiter of the present invention configured as described above, the coil spring is press-fitted and fixed to the inner ring in the outer tubular member during assembly, and the inner ring is inserted into the inner diameter of the coil spring. The hook at the rear coil spring end is engaged with the lid, and the lid is press-fitted and fitted into the outer cylinder member. When the lid is twisted in the direction opposite to the winding direction of the coil spring, the inner diameter of the coil spring is reduced, so that the inner diameter of the coil spring tightens the different diameter step portion of the inner ring for frictional engagement. By adjusting this frictional engagement force, the torque value as the torque limiter is set.

When the inner ring is rotated with respect to the outer tubular member, the frictional engagement force increases if the rotation of the inner ring reduces the diameter of the coil spring by frictional engagement, and the two rotate together. .. On the contrary, when the inner ring rotates in the direction to reduce the frictional engagement, the coil spring diameter increases, the frictional engagement is blocked, the rotation of the inner ring is not transmitted to the outer cylinder member, and the inner ring freely rotates in the opposite direction. .. The torque value at this time is the set torque value as the torque limiter. This set torque value can be adjusted by twisting the lid.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a main vertical sectional view of a torque limiter of an embodiment. In this torque limiter 10, a coil spring 13 is housed in a spring insertion portion 12 of an outer cylinder member 11 whose one end is open, and an inner ring 18 is provided in the inner diameter thereof. A projecting inner ring 16 is provided in the inner portion of the outer tubular member 11 on the end wall 15 side.
Is provided, the end of the coil spring 13 is press-fitted and fixed to the inner ring 16, and the hook 14 provided at the other end is the inner ring 1
8 is engaged with a recess provided in a lid 17 that closes the open end between the outer tubular member 11 and the outer tubular member 11.

The inner ring 18 has a large-diameter step portion 19 having a large diameter in the central portion of the parallel outer diameter, and its outer diameter D ₂ is a slight interference fit or a clearance fit with respect to the inner diameter of the coil spring 13. Is set to be. Outer diameter D of inner ring 11
₁ is set to a size that allows a slight interference fit with respect to the inner diameter of the coil spring 13, and the inner diameter is set to a size that allows a slight clearance with respect to the inner ring 18 to rotatably support the end of the inner ring 18. is doing. Further, the outer diameter D ₁ is set to be slightly larger than the outer diameter D ₂ of the different-diameter step portion 19 of the inner ring 18 (D ₁ > D ₂ ).

The coil spring 13 has an inner diameter that is substantially the same over its entire length, and is set to have a relatively large interference fit with respect to the outer diameter of the inner ring. Further, the end on the inner ring side has no hook, and the hook 14 is provided only on the lid 17 side. The lid 17 is fixed to the outer tubular member 11 by an interference fit or by unevenness provided on both.

The torque limiter of the embodiment constructed as described above operates as follows. When assembling the illustrated torque limiter, the inner ring side of the coil spring 13 is inserted into the outer tubular member 11 and is press-fitted into the gap between the inner ring 16 and the outer tubular member 11 so that Inner ring 1
8 is inserted and one end of the inner ring 18 is axially supported by the inner diameter of the inner ring 16. The hook 14 of the coil spring 13 fits into the recess of the lid 17 and presses the lid 17 into the outer cylinder member 11 to twist the lid 17 in a direction in which the diameter of the coil spring 13 is reduced. This twist direction is the left (right) direction when the coil spring is wound right (left). In this way, when the lid 17 is rotated and the coil spring is twisted, the diameter is reduced and the different diameter step portion 19 of the inner ring 18 is tightened. Then, the torque value as the torque limiter is set by adjusting the tightening force.

When the torque limiter set as described above is operated, the inner ring 18 is rotated with respect to the outer cylinder member 11 in any direction, for example, the rotation of the inner ring 18 causes the coil spring 13 to rotate.
The inner ring 18 if the direction to further increase the frictional engagement with
Tries to rotate integrally with the outer cylinder member 11 via the coil spring 13, and in the opposite direction, frictional engagement with the coil spring 13 enlarges the diameter of the coil spring 13 so that the engagement is interrupted and the inner ring 18 Rotate freely in the opposite direction.

As an example of the method of using the torque limiter that operates in this way, consider the case where the axial torque is transmitted from the outer cylinder member 11 to the inner ring 18, for example. Assuming that the shaft end of the outer cylinder member 11 is connected to the drive unit and the shaft end of the inner ring 18 is connected to the load, the rotational force of the drive unit is small and the reaction force causes frictional engagement with the coil spring. In the increasing direction (hereinafter referred to as the positive direction), the two rotate together and the rotational force is transmitted in that direction.

When a torque larger than a preset value is forcibly applied in the opposite direction, the diameter of the coil spring 13 increases and the frictional engagement with the inner ring 18 is blocked, so that the inner ring 18 is free to oppose. It will be able to rotate. The set torque value is the torque value of the torque limiter. In addition,
Clamping force f ₁ with respect to the inner ring D ₁ of the coil spring 13 is assumed to be largely set several times higher than the clamping force f ₂ with respect to the inner ring D ₂ parts of the coil spring 13. The torque value can be freely set within a predetermined range by adjusting the rotation angle of the lid 17 and changing the tightening force of the coil spring with respect to the inner ring 18.

[0019]

As described in detail above, the torque limiter of the present invention is provided with the coil spring and the inner ring in the outer tubular member, and the coil spring is press-fitted and fixed to the inner ring in the outer tubular member to secure the center of the inner ring. The outer diameter of the different-diameter step portion is set to be slightly smaller than the inner diameter of the coil spring so that the end is engaged with the lid and the lid is twisted to twist the coil spring to reduce the inner diameter and adjust the frictional engagement with the inner ring. The outer cylinder member, the coil spring,
It is easy to manufacture and assemble members such as the inner ring, moreover, the operation is reliable, and since the diameter of the coil spring for frictional engagement is large, the set torque can be increased.

[Brief description of drawings]

FIG. 1 is a main longitudinal sectional view of a torque limiter according to an embodiment.

FIG. 2 is a main longitudinal sectional view of a conventional torque limiter.

[Explanation of symbols]

 11 Outer Cylinder Member 13 Coil Spring 14 Hook 16 Inner Ring 17 Lid 18 Inner Ring 19 Different Diameter Step

Claims (1)

[Claims] 1. An inner ring having a large-diameter step portion with a large diameter in the central part of the length of the parallel shaft, and a coil spring wound around the outer periphery of the inner ring.
It is rotatably fitted into an outer cylinder member that is open at one end and has an inner ring at the back, and the open end between the inner ring and the outer cylinder member is closed with a lid, and the coil springs have the same inner diameter over the entire length. , One end is press-fitted and fixed to the outer diameter of the inner ring, and the other end is provided with a hook to be engaged with the lid, so that the stepped diameter of the different diameter of the inner ring is slightly interference fit or clearance fit slightly smaller than the coil spring inner diameter. In this way, the torque limiter can freely adjust the torque by changing the inner diameter of the coil spring by twisting the lid.