JP2002250361A - Torque limiter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assembling workability by using a member in place of a coil spring as an elastic member generating friction in a friction type torque limiter. SOLUTION: This limiter is constituted of an internal member 1, an external member 3 fitted into the internal member 1, a cylindrical spring 2 with a slit in the shaft direction, which is mounted by a required fastening force on the outer diameter surface of the internal member 1, and a cover 4 fitted into the external member 3 between the internal member 1 and the external member 3. By engaging a part of the cylindrical spring 2 to the external member 3, a corotation of the cylindrical spring 2 and the internal member 1 is prevented, and constant torque is generated by friction of the cylindrical spring 2 and the internal member 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter used for a paper transport unit in office machines such as copying machines and printers.

[0002]

2. Description of the Related Art As a torque limiter used in office equipment as described above, a friction type and a magnet type have been conventionally known. Conventionally known friction type torque limiters are disclosed, for example, in Japanese Patent Application Laid-Open No. 11-24 / 1999.
No. 7881, an internal member,
An outer member fitted to the inner member so as to be relatively rotatable,
A coil spring mounted on the outer diameter surface of the inner member with a required binding force, and a lid fitted to the outer member between the inner member and the outer member, wherein a hook at one end of the coil spring is provided. By engaging the hook at the other end with the lid while engaging with the external member, a constant torque is generated by friction between the internal member and the coil spring.

[0003] On the other hand, with the progress of downsizing and higher performance of office equipment, higher torque is required. For this reason, the present applicant has previously proposed a friction type torque limiter in which a plurality of coil springs are incorporated so that the torque can be adjusted (Japanese Patent Application No. 2000-65046). The coil spring in this case is used in a combination of a coil spring having a large diameter portion and a small diameter portion and a coil spring having only a small diameter portion, and the torque of the former small diameter portion and the torque of the latter small diameter portion are added. A predetermined torque is generated, and the former large-diameter portion serves as a torque adjusting unit.

[0004]

When the above-mentioned friction type torque limiter incorporates a coil spring, it is necessary to open the spring when engaging the hooks at both ends, and there is a problem in assemblability. .

Further, in order to generate a predetermined torque with a compact size, a magnet type torque limiter must use a rare earth magnet which generates a small and strong magnetic force, which raises the problem of high cost. In addition, in assembly, it is necessary to manage the gap between the magnet and the semi-magnetic material, and there is a problem in assemblability.

[0006] Further, the friction type torque limiter according to the above-mentioned proposal for achieving a high torque is a one-way torque limiter. Therefore, in order to cope with rotation in both the left and right directions, two types of coil springs having different coil springs in each winding direction are incorporated. Therefore, there is a problem that the number of parts management points increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a torque limiter having a good structure and a compact structure, and a torque limiter capable of reducing the number of parts management points.

[0008]

In order to solve the above-mentioned problems, a torque limiter according to the present invention comprises an internal member,
An outer member fitted to the inner member so as to be relatively rotatable,
An elastic member for generating torque mounted on an outer diameter surface or an inner diameter surface of the inner member with a required tightening force, and a lid fitted to an outer member between the inner member and the outer member, By engaging a part of the elastic member with the external member or the lid, co-rotation between the elastic member and the internal member is prevented, and a constant torque is generated by friction between the elastic member and the internal member. In the torque limiter,
A configuration in which the elastic member is formed by a cylindrical spring having a slit in the axial direction is employed.

According to the above construction, since the cylindrical spring has no directionality, it acts as a bidirectional torque limiter for generating a constant torque in either the left or right rotational direction.
Further, the work of mounting the cylindrical spring on the inner member and the outer member can be easily performed.

As another means for solving the above-mentioned problems, an internal member, an external member rotatably fitted to the internal member, and a required tightening force applied to the outer or inner diameter surface of the inner member. An elastic member for torque generation mounted thereon, and a lid fitted to the external member between the internal member and the external member, and a part of the elastic member is engaged with the external member or the lid. A torque limiter that prevents co-rotation between the elastic member and the internal member and generates a constant torque by friction between the elastic member and the internal member. A cylindrical spring and a coil spring, wherein the cylindrical spring is engaged with either the external member or the lid, and both ends of the coil spring are engaged with the external member and the lid, respectively. Structure It was adopted.

In this case, although acting as a one-way torque limiter, high torque can be obtained by both the tubular spring and the coil spring. Although the coil spring has directionality, the cylindrical spring has no directionality, so that the types of management parts can be reduced as compared with the case where both are formed by coil springs.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment] A first embodiment shown in FIGS. 1 and 2 comprises a cylindrical inner member 1, a cylindrical spring 2 mounted on an outer diameter surface thereof with a required tightening force, and a cylindrical member. It comprises a cylindrical outer member 3 fitted externally to the inner member 1 so as to cover the spring 2, and an annular lid 4 for closing between the inner member 1 and one end of the outer member 3.

At one end of the internal member 1, two engagement recesses 5 are provided, and these engagement recesses 5 allow the shaft (not shown) to be inserted into the inner diameter of the internal member 1 in the radial direction. The pin is engaged.

The cylindrical spring 2 is formed by winding an elastic metal plate or a plastic plate into a cylindrical shape and forming a slit 6 at one position in the axial direction. The protruding engagement pieces 7, 7 are bent.
The size of the inner diameter of the cylindrical spring 2 in a natural state is
It is formed smaller than the outer diameter of the inner member 1 by a required dimension.
For this reason, when the cylindrical spring 2 is expanded in diameter and mounted on the outer diameter surface of the internal member 1, a predetermined tightening force is exerted on the internal member 1 by the contractive elasticity of the cylindrical spring 2.

The outer member 3 is provided with a fitting portion 8 at one end of the inner diameter surface, and supports the inner member 1 fitted in this portion in a concentric manner and rotatably. In addition, a shaft insertion hole 10 is provided at a central portion of the fitting portion 8. The inner diameter surface 9 of the outer member 3 is formed to have an inner diameter larger than the outer diameter of the inner member 1, and the inner diameter surface 9 covers the cylindrical spring 2. An axial rib 11 is provided at one location on the inner diameter surface 9, and the engagement pieces 7 of the cylindrical spring 2 are engaged with both surfaces of the rib 11. Thereby, the cylindrical spring 2 has a predetermined tightening force on the internal member 1,
In addition, co-rotation with the internal member 1 in both left and right directions is prevented.

A circumferential fitting groove 12 is formed at the open end of the external member 3 on the inner diameter surface. In addition, the outer end face of the external member on the side of the fitting portion 8 is provided with an engagement protrusion 13 with the external member.
Is provided.

The lid 4 is fitted to the outer diameter surface of the inner member 1 with a rotatable gap, and a circumferential rib 14 formed on the outer diameter surface is fitted to the fitting groove 12 with a required frictional force. Are combined. The frictional force does not cause slippage with the force acting upon normal torque transmission, but is set to such an extent that slippage occurs when the external force is turned to adjust the torque.

The torque limiter of the first embodiment is as described above. When the external member 3 is fixed and the internal member 1 is rotated, the internal member 1 rotates with the friction caused by the tightening force of the cylindrical spring 2. As a result, a constant torque is generated regardless of the rotation in either the left or right direction.

[Second Embodiment] Next, in the second embodiment shown in FIGS. 3 and 4, the engagement structure of the cylindrical spring 2 with the external member 3 of the first embodiment is changed. Things. Other configurations and operations are the same. That is, although the cylindrical spring 2 in this case has the slit 6 as in the above-described case, one end portion (fitted to the fitting portion 8) is used instead of the engagement pieces 7 and 7 described above. At the opposite end of the slit 6, an engaging projection 15 is provided. A plurality of engaging concave portions 16 that fit into the engaging convex portions 15 are provided in the fitting portion 8. By the engagement between the engaging projections 15 and the engaging recesses 16, the cylindrical spring 2 is prevented from rotating together with the internal member 1.

In FIG. 3, the internal member 1 and the lid 4 are not shown.

The shapes of the projections and depressions of the engaging projections 15 and the engaging recesses 16 may be reversed as shown in FIGS. That is, FIG.
5 ′ is provided, and the engaging protrusion 16 ′ is provided on the fitting portion 8 on the side of the external member 3.
Is provided. However, the engaging concave portion 15 'is an engaging portion formed as a result of the above-mentioned engaging convex portion 15 expanding in the circumferential direction, and the engaging convex portion 16' is the same as the above-mentioned engaging concave portion 16 3 and 4, it can be said that the engagement portion is substantially the same as that shown in FIGS.

Further, as shown in FIG. 7, a cylindrical spring 2 'can be mounted on a counterbore 20 provided on the inner diameter surface of the internal member 1. The tubular spring 2 'in this case has an axial slit 6 like the tubular spring 2 described above,
One end face has an engaging projection 15 and is engaged with the engaging recess 16 of the fitting portion 8. In this case, the outer diameter of the cylindrical spring 2 ′ in this case is formed slightly larger than the inner diameter of the inner member 1 in a natural state, and imparts elasticity in the expanding direction to the inner diameter surface. Other configurations and operations are the same as those described above.

[Third Embodiment] A third embodiment shown in FIGS. 8 and 9 has a cylindrical shape having an axial slit 17 in a cylindrical body formed of an elastic member like the above-described cylindrical spring 2. Of the cylindrical spring 2 of the second embodiment with a required tightening force. The tightening force of the cylindrical spring 2 against the internal member 1 is doubled, and a high torque is obtained. In this case, the cylindrical spring 2 is referred to as a “main spring” in the claims to distinguish it from the cylindrical auxiliary spring 18. Cylindrical spring (main spring) 2
The difference between the former and the auxiliary spring 8 is that the former has an engaging portion with the external member 3, whereas the latter does not engage with the external member 3 but engages with the cylindrical spring (main spring) 2. . This is the same in other embodiments.

The other structure is the same as that of the second embodiment (see FIGS. 3, 4, 5, and 6).

As described above, by adopting a structure in which the auxiliary spring 18 is fitted to the outer diameter surface of the cylindrical spring (main spring) 2, it is possible to increase the torque without increasing the axial length of the entire torque limiter. be able to.

As another means for increasing the torque using the auxiliary spring 18, there is a configuration shown in FIGS. In this case, the inner member 1 and the outer member 3 in the second and third embodiments are formed to be long in the axial direction, and the rear end (the engagement protrusion) of the cylindrical spring (main spring) 2 in each of these embodiments. Part 15
(The end opposite to the end with the groove) is provided with an engagement recess 19, and the engagement protrusion 15 of the auxiliary spring 18 having the same size and the same structure and having the axial slit 17 is engaged, and The rotation is prevented. In this case, the torque can be increased by doubling the friction surface that contributes to the torque generation. Further, a cylindrical spring (main spring) 2 and an auxiliary spring 18
Has the advantage that the same parts can be used.

[Fourth Embodiment] In a fourth embodiment shown in FIG. 12, a cylindrical spring 2 'is mounted on the inner surface of the inner member 1 by counterbore, as in the case of FIG. 7 of the second embodiment. The cylindrical spring 2 is mounted on the outer diameter surface of the internal member 1 while being mounted on the portion 20. The cylindrical spring 2 'in this case is different from the auxiliary spring 18 in that the engaging convex portion 15 is engaged with the engaging concave portion 16 of the external member 3, but in that a higher torque can be achieved. Common.

Similarly, as means for increasing the torque by using the independent cylindrical springs 2, as shown in FIGS. The engaging protrusion 15 of one tubular spring 2 is engaged with the engaging recess 16 of the fitting portion 8 of the external member 3, and the engaging protrusion 15 of the other tubular spring 2 Engaging recess 16 provided in lid 4
Can be adopted. In this case, the two tubular springs 2, 2 are the same part.

Fifth Embodiment Next, a fifth embodiment shown in FIG. 15 is a torque limiter adopting a combination structure of the above-mentioned tubular spring 2 and coil spring 21. That is, the tubular spring 2 in this case is the same as that of the first embodiment described above (see FIGS. 1 and 2), and the tubular spring 2 is an end portion of the internal member 1 on the fitting portion 8 side. Is mounted on the outer diameter surface of the internal member 1, and the engagement piece 7 of the cylindrical spring 2 is engaged with the rib 11.

On the other hand, the coil spring 21 has a large-diameter portion 22 and a small-diameter portion 23, and the small-diameter portion 23 is attached to the internal member 1 with a required binding force. There is a gap. The hook 24 on the large diameter portion 22 side is the lid 4
And the hook 25 on the small diameter portion 23 side is
Is engaged. By forcibly rotating the lid 4 from the outside, the binding force of the small diameter portion 23 changes, and the torque value is adjusted.

In the torque limiter having the above structure, since the torque value of the cylindrical spring 2 is added to the torque value of the one-way torque limiter in the case of using only the coil spring 21, the torque can be increased, and the torque value can be reduced. Can be changed.

FIG. 16 shows a modification of the above embodiment, in which the engaging projection 15 provided at one end of the cylindrical spring 2 is fitted to the external member 3 as in the case of FIG. It is engaged with an engagement recess 16 provided in the portion 8. The hook 25 of the coil spring 21 is engaged with the engagement groove 11 ′ provided on the inner surface of the outer member 3.

The other structure and operation are the same as those in FIG.

Sixth Embodiment A sixth embodiment shown in FIG. 17 is a torque limiter comprising the same combination of the cylindrical spring 2 and the coil spring 21 as described above. Is mounted on the outer diameter surface of the inner member 1 inside the large diameter portion 22 of the coil spring 21 to reduce the axial length of the entire product. The engaging projection 15 of the tubular spring 2 is engaged with an engaging recess 16 provided on the lid 4. The hooks 24 and 25 of the coil spring 21 are engaged with the lid 4 and the external member 3.

The hook 25 may be engaged with the engaging groove 11 'of the external member 3 as shown in FIG. Further, as shown in FIG. 19, the cylindrical spring 2 is mounted on the counterbore 20 on the inner surface of the inner member 1 so that the engaging protrusion 15 is engaged with the engaging recess 16 of the outer member 3. It may be.

[0037]

As described above, the present invention uses a cylindrical spring provided with a slit as an elastic member for generating torque. It can be used as a bidirectional torque limiter that generates a constant torque. Further, the work of mounting the cylindrical spring on the inner member and the outer member is easy. Further, by using a plurality of tubular springs, a high torque can be achieved.

The use of a combination of the above-mentioned tubular spring and coil spring has the advantages of increasing the torque and reducing the number of parts to be managed as compared with the combination of coil springs.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a first embodiment.

FIG. 2A is a sectional view of an assembled state of the same, and FIG. 2B is a sectional view taken along line bb in FIG.

FIG. 3 is an exploded perspective view showing a part of the second embodiment in a partial cross section.

4A is a cross-sectional view of the same assembling state; FIG. 4B is a cross-sectional view taken along line bb in FIG. 4A; FIG. 4C is a cross-sectional view taken along line cc in FIG.

FIG. 5 is an exploded perspective view showing a part of a modification of the second embodiment in a partial cross section.

6A is a sectional view of the same assembling state, and FIG. 6B is a sectional view taken along line bb in FIG. 6A. FIG. 6C is a sectional view taken along line cc in FIG.

7A is a cross-sectional view of another modification of the second embodiment. FIG. 7B is a cross-sectional view taken along line bb in FIG. 7A. FIG. 7C is a cross-sectional view taken along line cc in FIG.

8A is an exploded perspective view showing a part of the third embodiment, and FIG. 8B is a perspective view showing an assembled state in the case of FIG.

FIG. 9 is a sectional view showing an assembled state of the above.

FIG. 10 is an exploded perspective view showing a part of a modification of the third embodiment in a partial cross section.

FIG. 11 is a sectional view showing an assembled state of the above.

12A is a cross-sectional view of the fourth embodiment. FIG. 12B is a cross-sectional view taken along line bb in FIG.

FIG. 13 is an exploded perspective view showing a part of a modification of the fourth embodiment.

FIG. 14 is a sectional view showing an assembled state of the same.

15A is a cross-sectional view of the fifth embodiment. FIG. 15B is a cross-sectional view taken along line bb in FIG.

16A is a sectional view of a modification of the fifth embodiment, and FIG. 16B is a sectional view taken along line bb in FIG.

FIG. 17 is a sectional view of the sixth embodiment.

FIG. 18 is a sectional view of a modification of the sixth embodiment.

FIG. 19 is a sectional view of another modification of the sixth embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal member 2, 2 'Tubular spring 3 External member 4 Lid 5 Engaging recess 6 Slit 7 Engaging piece 8 Fitting part 9 Inner diameter surface 10 Shaft insertion hole 11 Rib 11' Engaging groove 12 Fitting groove 13 Engage Projection 14 Circumferential rib 15 Engagement convex part 15 'Engagement concave part 16 Engagement concave part 16' Engagement convex part 17 Slit 18 Auxiliary spring 19 Guide rail 20 Counterbore part

Claims (11)

[Claims] An inner member, an outer member rotatably fitted to the inner member, and an elastic member for generating torque mounted on an outer or inner surface of the inner member with a required tightening force. And a lid fitted to the external member between the internal member and the external member, and by engaging a part of the elastic member with the external member or the lid, the elastic member and the internal member are separated from each other. A torque limiter for preventing corotation and generating a constant torque by friction between the elastic member and the internal member, wherein the elastic member is formed by a cylindrical spring having a slit in an axial direction. Torque limiter. 2. The cylindrical spring for generating torque is mounted on an outer diameter surface of the internal member, and engagement portions provided on both sides of a slit of the cylindrical spring in a radially outward direction are engaged with the external member. The torque limiter according to claim 1, wherein the torque limiter is combined. 3. The method according to claim 1, wherein an engaging portion is provided on an end surface of the tubular spring for generating torque, and the engaging portion is engaged with an inner end surface of the outer member or an inner surface of the lid. The torque limiter according to 1. 4. An auxiliary spring constituted by a cylindrical spring having a slit in an axial direction on an outer diameter surface of the cylindrical spring for generating torque is fitted as a main spring with a clamping force in a radial direction. The torque limiter according to claim 3, wherein the torque limiters are combined. 5. An auxiliary spring constituted by a cylindrical spring having a slit in an axial direction at an end opposite to an engagement portion of the main spring, wherein the cylindrical spring for generating torque is a main spring. 4. The torque limiter according to claim 3, wherein the inner member has a radial tightening force and is fitted in series with the main spring in mutual engagement. 6. The torque limiter according to claim 3, wherein the cylindrical spring for generating torque is mounted at two positions on an inner diameter surface and an outer diameter surface of the inner member. 7. The torque limiter according to claim 3, wherein the cylindrical spring for generating torque is mounted at two axial positions of the internal member. 8. An inner member, an outer member rotatably fitted to the inner member, and an elastic member for generating torque mounted on an outer or inner surface of the inner member with a required tightening force. And a lid fitted to the external member between the internal member and the external member, and by engaging a part of the elastic member with the external member or the lid, the elastic member and the internal member are separated from each other. In a torque limiter for preventing co-rotation and generating a constant torque by friction between the elastic member and an internal member, a combination of a cylindrical spring having a slit in an axial direction and a coil spring is provided. A torque limiter, wherein the cylindrical spring is engaged with either the external member or the lid, and both ends of the coil spring are engaged with the external member and the lid, respectively. 9. The torque limiter according to claim 8, wherein the cylindrical spring and the coil spring are arranged in series in an axial direction on an outer diameter surface of the inner member. 10. The torque limiter according to claim 8, wherein said tubular spring is mounted on an inner diameter surface of said inner member, and said coil spring is mounted on an outer diameter surface of said inner member. 11. A large-diameter portion and a small-diameter portion are provided in the coil spring, and the small-diameter portion is mounted on an outer-diameter surface of the internal member with a required binding force, and the cylindrical spring is provided inside the large-diameter portion. The torque limiter according to claim 8, wherein the torque limiter is mounted on an outer diameter surface of the inner member.