JPH10148219A - Torque limiter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque limiter in which a second frictional member may not be unevenly worn, balance of the frictional conditions of both surfaces of respective members is excellent, and a stable torque is transmitted from a driving member to a driven member. SOLUTION: In this torque limitter 1, a first frictional member 5 slidably brought into contact with the flange part 10 of a driving member 2, a driven member 3 slidably brought into contact with the first frictional member 5, a second frictional member 6 slidably brought into contact with the driven member 3 and a frictional member reinforcing plate 7 slidably brought into contact with the second frictional member 6, are fitted in the shaft part 9 of the driving member 2, and a pressure regulating member 4 and a presser nut 18 are screwed around a screw part 12 through an elastic member 8 in a compressed state.

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 transmitting torque in OA equipment such as a printer.

[0002]

2. Description of the Related Art As an example of a conventional torque limiter,
A description will be given based on FIG. 3 and FIG. First, as shown in FIG. 3, the torque limiter 1 includes a driving member 2, a driven member 3, a pressure adjusting nut 4 as a pressure adjusting member, a first friction material 5, a second friction material 6, It comprises a friction material reinforcing plate 7 bonded and fixed to the two friction materials 6 and a pressure spring 8 as an elastic member.

The driving member 2 has a shaft portion 9 and a disk-shaped flange portion 10 formed at one end of the shaft portion 9. A drive gear 11 is formed on the outer periphery of the flange portion 10. A driving force from a driving source (not shown) is transmitted to the driving gear 11. A screw portion 12 is formed at the other end of the shaft portion 9. The support means 13 includes the screw portion 1
2 and a female thread cut into the pressure adjusting nut 4, and the pressure adjusting nut 4 is screwed into the screw portion 12.

A driven gear 14 is formed on the outer periphery of the driven member 3.

[0005] The driven member 3, the first friction material 5, and the second friction material 6
The friction material reinforcing plate 7 and the friction material reinforcing plate 7 each have a disk shape, and have holes 3a, 5a, 6a, and 7a at their centers. These holes 3a, 5a, 6a, 7a are circular holes having a diameter slightly larger than the diameter of the shaft portion 9. The holes 3a, 5a, 6a, and 7a allow the shaft portions 9 to be respectively provided.
Is inserted with a gap between the shaft portion 9 and the outer peripheral surface.

[0006] The order of insertion into the shaft portion 9 is as follows.
0 through the first friction material 5, the driven member 3, and the second friction material 6 and the friction material reinforcing plate 7, which are bonded and fixed to each other, and the compression spring 8. The pressure adjusting nut 4 is screwed together. Here, the shaft portion 9, the first friction material 5, the driven member 3, and the second friction material 6
Each is slidable.

In such a structure, the pressing force of the pressing spring 8 is adjusted by the pressure adjusting nut 4. By this adjustment, the limit torque of the torque limiter 1, that is, the torque at the boundary when the power transmission from the driving member 2 to the driven member 3 is interrupted is determined.

When the torque applied to the driven member 3 is equal to or less than the limit torque, the power of the driving member 2 is transmitted to the driven member 3 by the frictional force acting on both surfaces. Further, when the torque applied to the driven member 3 becomes equal to or larger than the limit torque, power is not transmitted.

Here, when power is no longer transmitted,
The pressure adjusting nut 4 is moved from the stopped driven member 3 via the second friction material 6, the friction material reinforcing plate 7 and the pressure spring 8,
It may rotate under the force of the anti-rotational direction, and the pressure of the pressure spring 8 may be loosened. When the pressurization is loosened, the limit torque fluctuates. As means for preventing this, for example, as shown in FIG. 4, there is one described in Japanese Utility Model Publication No. 7-43477.
In this configuration, a groove 15 is formed in the shaft portion 9, and a projection 16 is provided in the pressure adjusting nut 4. The projection 16 is locked by a clip 17 fitted in the groove 15, and the pressure adjusting nut is 4 is fixed so as not to rotate, thereby preventing the pressure of the pressure spring 8 from being loosened.

[0010]

In the conventional torque limiter 1 having the structure as shown in FIG. 3, the second friction material 6 and the friction material reinforcing plate 7 are bonded and fixed. With such a structure, the second friction material 6 rubs only with the driven member 3 and receives a friction load on only one surface. For this reason, the second friction material 6
Has a short life because only one side is worn.

Further, the second friction material 6 is in a state of being indirectly fixed to the driving member 2 via the friction material reinforcing plate 7, the pressing spring 8, and the pressure adjusting nut 4. Accordingly, one surface of the driven member 3 is rubbed by the first friction material 5 slidable with respect to the driving member 2, and the other surface is a second friction material indirectly fixed to the driving member 2. The material 6 is being rubbed. That is, the frictional states of both surfaces of the driven member 3 are different from each other, and the transmission of torque is unstable.

In the method of bonding and fixing the second friction material 6 and the friction material reinforcing plate 7, since heat is generated by friction when the torque limiter 1 is used, an adhesive capable of withstanding high temperatures must be used. . Therefore, conventionally, a thermosetting resin that cures when heated is used for the adhesive. However, since the thermal expansion coefficients of the second friction material 6 and the friction material reinforcing plate 7 are different from each other, when they are heated and bonded, when they are cooled, the second friction material 6 and the friction material reinforcing plate 7 are integrated. The phenomenon of warping occurs. Therefore, it is difficult to keep the second friction material 6 flat. If the second friction material 6 is not flat, the frictional force between the second friction material 6 and the driven member 3 will not be stable. On the other hand, since the first friction material 5 is flat, the friction force between the first friction material 5 and the driven member 3 is stable. That is,
Since the frictional states of both surfaces of the driven member 3 are different, torque transmission is unstable.

A clip 17 having a structure as shown in FIG.
In the method of preventing the pressing force from loosening by locking the pressure adjusting nut 6 with the pressure adjusting nut 4, the projection 16 must be aligned with the position corresponding to the groove 15, which is inconvenient for fine adjustment. Further, it is not easy to fit the clip 17 in alignment with the protrusion 16 and the groove 15.

In view of the above, according to the present invention, the life of the second friction material is long, the balance of the frictional state of both surfaces of each member is good, and the frictional state of both surfaces of the driven member is particularly equal, and it is possible to finely adjust the limit by simple means. It is an object of the present invention to obtain a torque limiter capable of preventing torque fluctuation and transmitting a stable torque.

[0015]

According to the first aspect of the present invention, a driving member having a shaft portion and a disk-shaped flange portion is provided,
A first friction material, a driven member, a second friction material, and a friction material reinforcing plate are slidably fitted in this shaft portion in this order, and a pressure adjusting member is further mounted on the shaft portion by supporting means. The elastic member is supported between the friction material reinforcing plate and the pressure adjusting member in a compressed state. Therefore, the second friction material is rubbed by the driven member and the friction material reinforcing plate and receives a friction load on both surfaces, so that only one surface is not worn. Further, since the second friction material is not bonded and fixed to the friction material reinforcing plate, the second friction material is kept flat without warping due to a difference in thermal expansion coefficient.

According to a second aspect of the present invention, the friction coefficient of the sliding surface between the flange portion and the first friction member, the friction coefficient of the sliding surface between the first friction member and the driven member, and the friction coefficient between the driven member and the second friction member are determined. The friction coefficient of the sliding surface with the material is equal to the friction coefficient of the sliding surface with the second friction material and the friction material reinforcing plate. Therefore, the frictional state of both surfaces of each member becomes equal.

According to the third aspect of the present invention, one end of the pressure spring is fixed to the friction material reinforcing plate. Therefore, since the friction material reinforcing plate is indirectly fixed to the drive member, the first and second friction materials rub against the driven member in substantially the same state.

According to the fourth aspect of the present invention, the nut is used as a pressure adjusting member, and this pressure adjusting member is screwed into a male screw cut at the end of the shaft portion, and further, the holding nut is screwed until it comes into contact with the pressure adjusting member. Let it. Therefore, when power is no longer transmitted, the pressure adjusting member does not rotate even when indirectly receiving a force in the anti-rotational direction from the stopped driven member 3.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.
A description will be given based on FIG. 1 and FIG. Note that the same portions as those shown in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the second friction material 6 and the friction material reinforcing plate 7
Are not fixedly adhered to each other, but are inserted into the shaft portion 9 so as to be slidable adjacent to each other.

With such a configuration, one surface of the second friction material 6 rubs against the driven member 3 and the other surface rubs against the friction material reinforcing plate 7, so that the second friction material 6 is provided on both surfaces. Subject to frictional load. Therefore, since only one side is not worn, the life of the second friction material 6 is prolonged. Further, since the second friction material 6 is not bonded and fixed to the friction material reinforcing plate 7, warpage due to a difference in thermal expansion coefficient does not occur, and the second friction material 6 has a flat surface. There is no loss of adhesion between the second friction material 6 and the second friction material 6.

In this embodiment, the driving member 2, the driven member 3, and the friction material reinforcing plate 7 are formed of the same material. Specific materials include polyphenylene oxide (polyphenylene oxide) and polyphenylene sulfide (polyphenylene oxide).
sulfide, polyacetal resin (polya)
There is an engineering plastic represented by, for example, a catalytic resin. Driven member 3 and friction material reinforcing plate 7
Means that the engineering plastic has a self-lubricating property, so that it is not necessary to separately provide a bearing. Further, when the engineering plastic is impregnated with a lubricant or oil, higher self-lubricating properties can be obtained.

Further, in the present embodiment, the first friction material 5
And the second friction material 6 are formed of the same material. The material is, for example, a high-strength fiber such as steel fiber, glass fiber, boron fiber, alaside fiber, or fluorine fiber as a base material, and the base material is represented by Teflon, polychlorotrifluoroethylene, epoxy, or the like. A sheet-like material impregnated or immersed with a synthetic resin or an engineering plastic is preferred.

As described above, when the driving member 2, the driven member 3, and the friction material reinforcing plate 7 are formed of the same material, and the first friction material 5 and the second friction material 6 are formed of the same material, The friction coefficient of each friction surface becomes equal. Therefore, the frictional state of both surfaces of each member becomes equal, and the transmission of torque is stabilized.

In this embodiment, one end of the pressure spring 8 is fixed to the friction material reinforcing plate 7.

With such a configuration, the friction material reinforcing plate 7
Are indirectly fixed to the driving member 2, and the first and second friction members rub against the driven member in substantially the same state. Therefore, the frictional states of both surfaces of the driven member 3 become substantially equal, and stable torque is transmitted.

Further, in this embodiment, after the pressing force of the pressure spring 8 is adjusted by the pressure adjusting nut 4, the pressing nut 18 is further screwed into the screw portion 12 into which the pressure adjusting nut 4 is screwed.
Are screwed into contact with the pressure adjusting nut 4.

With such a configuration, when power is no longer transmitted, the pressure adjusting nut 4 does not rotate even if it indirectly receives a force in the anti-rotational direction from the stopped driven member 3. The pressing force of the pressing spring 8 does not slack, and the limit torque does not change.

The friction material reinforcing plate 7 may be made of an elastic material such as metal, plastic or rubber.

[0029]

According to the first aspect of the present invention, a driving member having a shaft portion and a disk-shaped flange portion is provided, and the first friction material, the driven member, the second friction material, and the friction material reinforcing plate are provided on the shaft portion. Are slidably fitted to each other in this order, and further,
The pressure adjusting member is supported by the supporting means so as to be movable and fixed in the axial direction, and the elastic member is clamped between the friction material reinforcing plate and the pressure adjusting member in a compressed state. Has friction with the driven member, the other surface has friction with the friction material reinforcing plate, and the second friction material receives a friction load on both surfaces. Therefore, since only one surface is not worn, the life of the second friction material can be extended. further,
Since the second friction material is not bonded and fixed to the friction material reinforcing plate, warpage due to a difference in thermal expansion coefficient does not occur, and the surface of the second friction material in contact with the driven member remains flat. A stable torque can be transmitted without impairing the adhesion to the friction material.

According to a second aspect of the present invention, the friction coefficient of the sliding surface between the flange portion and the first friction material, the friction coefficient of the sliding surface between the first friction material and the driven member, and the friction coefficient between the driven member and the second friction material are determined. Since the friction coefficient of the sliding surface with the material and the friction coefficient of the sliding surface with the second friction material and the friction material reinforcing plate are equalized, the frictional state of both surfaces of each member becomes equal, so that a stable torque is obtained. Can be transmitted.

According to the third aspect of the present invention, since one end of the pressure spring is fixed to the friction material reinforcing plate, the friction material reinforcing plate is indirectly fixed to the driving member. The friction material rubs the driven member in substantially the same state, so that the frictional states of both surfaces of the driven member become substantially equal, and a stable torque can be transmitted.

According to a fourth aspect of the present invention, the nut is used as a pressure adjusting member, the pressure adjusting member is screwed into a male screw cut at the end of the shaft portion, and the holding nut is further screwed into contact with the pressure adjusting member. Therefore, when the power is no longer transmitted, the pressure adjusting member does not rotate even if indirectly receiving a force in the anti-rotational direction from the stopped driven member, so that the pressure of the pressure spring does not loosen, Limit torque does not fluctuate. Therefore, stable torque can be transmitted.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the present invention.

FIG. 2 is a front view showing an embodiment of the present invention.

FIG. 3 is a vertical sectional front view showing an example of the related art.

4 (a) is a perspective view and FIG. 4 (b) is a right side view showing a conventional example of a means for preventing fluctuation of limit torque.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Torque limiter 2 Drive member 3 Follower member 4 Pressure adjusting member 5 First friction material 6 Second friction material 7 Friction material reinforcing plate 8 Elastic member 9 Shaft 10 Flange 11 Drive gear 13 Supporting means 14 Follower gear 18 Pressing nut

Claims (4)

[Claims] A driving member having a shaft portion and a disk-shaped flange portion, a first friction material inserted into the shaft portion and slidably in contact with the flange portion, and fitted to the shaft portion. A disk-shaped driven member inserted and slidably in contact with the first friction material, a second friction material inserted into the shaft portion and slidably in contact with the driven member, and fitted into the shaft portion; A friction material reinforcing plate which is inserted and slidably contacts the second friction material, a pressure adjusting member which clamps an elastic member in a compressed state between the friction material reinforcing plate and the shaft portion; And a supporting means movably in the axial direction and fixedly supported at an arbitrary position of the shaft portion. 2. A friction coefficient between a sliding surface between a flange portion and a first friction material, a friction coefficient between a sliding surface between the first friction material and a driven member, and a friction coefficient between the driven member and a second friction material. 2. The torque limiter according to claim 1, wherein the friction coefficient of the sliding surface is equal to the friction coefficient of the sliding surface between the second friction material and the friction material reinforcing plate. 3. The torque limiter according to claim 1, wherein one end of the pressure spring is fixed to the friction material reinforcing plate. 4. A nut as a pressure adjusting member, a female screw cut into the pressure adjusting member and a male screw cut into an end of the shaft portion having no flange portion as supporting means, and screwed into the male screw to form the nut. 4. The torque limiter according to claim 1, further comprising a holding nut for contacting the pressure adjusting member.