WO2015145649A1

WO2015145649A1 - Torque limiter and torque limiter unit

Info

Publication number: WO2015145649A1
Application number: PCT/JP2014/058801
Authority: WO
Inventors: 晴日井内; 勇森本; 俊一渡邉; 俊男飯山
Original assignee: オリジン電気株式会社
Priority date: 2014-03-27
Filing date: 2014-03-27
Publication date: 2015-10-01
Also published as: JP5615996B1; JPWO2015145649A1

Abstract

[Problem] To provide a torque limiter with which a rotational torque of a specified value can be obtained even when the coil spring is made smaller. [Solution] The coil spring (13) is formed by lining up multiple single coil springs and is interference-fitted on a cylindrical inner ring member (12), which is formed from a resin, in contact with the outer circumferential surface thereof. One end of the coil spring (13) is held by an outer ring member (14). When the torque between the inner ring member (12) and the outer ring member (14) is at or below a specified value, the coil spring (13) transmits torque between the inner ring member (12) and the outer ring member (14) without slipping. When the torque between the inner ring member (12) and the outer ring member (14) exceeds the specified value, the coil spring (13) slips and blocks torque transmission between the inner ring member (12) and the outer ring member (14).

Description

Torque limiter and torque limiter unit

The present invention relates to a torque limiter and a torque limiter unit that transmit torque below a predetermined value and block transmission of torque exceeding a predetermined value.

In general, when an excessive torque exceeding a predetermined value is applied, the torque limiter cuts off the transmission of the excessive torque. For example, the torque limiter cuts off the paper feeding, conveying and discharging portions of a printer such as an OA device or a copying machine. Widely used in mechanisms.

There are contact type torque limiters that can obtain rotational torque by mechanical friction, and contact type torque limiters are generally composed of three parts: an inner ring member, a coil spring, and an outer ring member. A coil spring is tightly fitted to the outer periphery of the inner ring member and fixed to the outer ring member, and a predetermined rotational torque is obtained by mechanical friction between the inner ring member and the coil spring.

As such a contact type torque limiter, the inner ring member is rotatably housed inside the outer ring member, a coil spring is tightly fitted around the inner ring member, and a hook provided at the end is fixed to the outer ring member. (For example, refer to Patent Document 1).

FIG. 7 is a block diagram showing an example of a conventional torque limiter. The torque limiter 11 is configured by fastening a coil spring 13 to the outer periphery of the inner ring member 12 and fixing one end of the coil spring 11 to the outer ring member 14. The coil spring 13 has a spirally swiveled shape, is in close contact with the outer peripheral surface of the inner ring member 12, and has a predetermined rotational torque obtained by mechanical friction between the outer peripheral surface of the inner ring member 12 and the coil spring 13. I am trying to do it. The inner ring member 12 is provided with a shaft coupling groove 12A. The shaft coupling groove 12A is engaged with a shaft coupling part provided on a shaft (not shown) so that the shaft is coupled to the inner ring member 12.

JP-A-5-26254

However, the contact type torque limiter has a structure in which rotational torque can be obtained by friction sliding between the inner ring member and the coil spring. Usually, the inner ring member is made of resin, and the coil spring is made of metal. Wears due to frictional sliding. Therefore, in order to reduce wear of the inner ring member, an expensive PPS (Polyphenylenesulfide) material containing a large amount of carbon fiber is used for the inner ring member. This increases the cost.

Further, the coil spring 13 may be made of resin instead of metal, and the inner ring member 12 may be made of ordinary resin, but in that case, a predetermined rotational torque may not be obtained. In particular, when the torque limiter is downsized, it is difficult to obtain a predetermined rotational torque.

An object of the present invention is to provide a torque limiter and a torque limiter unit capable of obtaining a predetermined rotational torque even when a coil spring is downsized.

A torque limiter according to a first aspect of the present invention includes a cylindrical inner ring member formed of resin, a coil spring formed by connecting a plurality of one-turn springs, and being in close contact with the outer peripheral surface of the inner ring member. When the torque between the outer ring member holding one end of the coil spring and the inner ring member and the outer ring member is less than a predetermined value, the coil spring does not slip between the inner ring member and the outer ring member. Torque transmission is performed, and when the torque between the inner ring member and the outer ring member exceeds a predetermined value, the coil spring slips to block torque transmission between the inner ring member and the outer ring member. And

The torque limiter according to the invention of claim 2 is characterized in that, in the invention of claim 1, the coil spring has a shape in which a mold can be pulled out in two directions.

A torque limiter unit according to a third aspect of the invention includes the torque limiter according to the first or second aspect, and a shaft that is provided through the inner ring member of the torque limiter and connected to the inner ring member. It is characterized by.

The torque limiter unit according to the invention of claim 4 is characterized in that, in the invention of claim 3, a rotating roller member is attached to the outer ring member of the torque limiter.

According to the present invention, a coil spring is formed by connecting a plurality of one-turn springs, so that a larger torque than that of the same plurality of coil springs having the same outer diameter can be produced. Therefore, even when the coil spring is downsized, a predetermined rotational torque can be obtained.

The block diagram of the torque limiter which concerns on 1st Embodiment of this invention. Explanatory drawing of the torque limiter which concerns on 2nd Embodiment of this invention. The block diagram of an example of the torque limiter unit which concerns on 3rd Embodiment of this invention. The block diagram of another example of the torque limiter unit which concerns on 3rd Embodiment of this invention. Explanatory drawing in the case of shape | molding the coil spring 13 in 2nd Embodiment of this invention with a molding machine. Explanatory drawing in the case of shape | molding the conventional coil spring 13 with a molding machine. The block diagram which shows an example of the conventional torque limiter.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a configuration diagram of a torque limiter according to a first embodiment of the present invention. In the torque limiter according to the first embodiment of the present invention, the coil spring 13 is formed by connecting a plurality of one-turn springs 13a to 13d to the conventional example shown in FIG. FIG. 1 shows a case where four one-turn springs 13a to 13d are provided. The same elements as those in FIG.

The first spring 13 a is in contact with the outer peripheral surface of the inner ring member 12 and is tightly fitted. One end is fixed to the outer ring member 14 and the other end is fixed to the connecting portion 15. The second spring 13 b is in contact with the outer peripheral surface of the inner ring member 12 and is tightly fitted. One end is not fixed and the other end is fixed to the connecting portion 15. Similarly, the third spring 13c and the fourth spring 13d are also fitted in contact with the outer peripheral surface of the inner ring member 12, one end is not fixed, and the other end is fixed to the connecting portion 15. ing. Thus, in the first embodiment of the present invention, the coil spring 13 is formed by four one-turn springs 13a to 13d.

Here, the slit torque Ts of the coil spring 13 is expressed by the following equation (1). μ is a friction coefficient, and N is the effective number of windings of the spring wound around the inner ring member 12. K is expressed by the following equation (2).

Ts = K {1- (1 / ε ^2πμN )} (1)
K = EIδ / R ² (2)
E is a longitudinal elastic modulus, I is a secondary moment of section, δ is a margin (for a radius), and R is a radius of the inner ring member 12. Assuming that K = 1 and μ = 0.11, Ts (N = 1) = 0.499 when the spring has one turn (N = 1) and Ts when the spring has two turns (N = 2) When (N = 2) = 0.745 and the spring has 3 turns (N = 3), Ts (N = 3) = 0.875.

On the other hand, the slit torque Ts (three) of the coil spring 13 when three springs each having one turn (N = 1) are used is Ts (three) = 0.499 × 3 = 1.497. On the other hand, the slit torque Ts (N = 3) of the three coil springs 13 is Ts (N = 3) = 0.875 as described above. Therefore, the ratio between Ts (three) and Ts (N = 3) is expressed by the following equation (3).

Ts (3) / Ts (N = 3) ≈1.71 (3)
The slit torque Ts (three) of the coil spring 13 when three springs with one turn (N = 1) are used is about 1.times. Of the slit torque Ts (N = 3) of one coil spring 13 with three turns. Seven times the torque can be obtained. As described above, by providing a plurality of one-turn springs, it is possible to output a larger torque than before with a spring having the same outer diameter.

Next, a second embodiment of the present invention will be described. 2A and 2B are explanatory views of a torque limiter according to a second embodiment of the present invention, in which FIG. 2A is a configuration diagram and FIG. 2B is a perspective view. The torque limiter according to the second embodiment of the present invention is such that the shape of the coil spring 13 is such that the mold can be pulled out in two directions.

When the coil spring 13 is formed of resin, the resin is injected into a mold and molded. Since the coil spring 13 has a spiral portion that spirally turns, in such a spring shape, a mold that can be pulled out in three or more directions must be slid and molded. Therefore, since it cannot be molded unless it is a large molding machine, the mold cost and the unit price of the product increase.

6A and 6B are explanatory diagrams when the conventional coil spring 13 is molded by a molding machine. FIG. 6A is a configuration diagram of the conventional coil spring 13, and FIG. 6B is a ZZ line of FIG. 6A. FIG. FIG. 6 shows a case where the outer ring 14 and the coil spring 13 are integrally formed.

As shown in FIG. 6A, when the die is slid in the two directions of the arrow A1 direction and the arrow A2 direction in the cross section taken along the line ZZ, a coil spring is obtained as shown in FIG. 6B. Since 13 is a spirally swiveled shape, the back is wide and the front is narrow as viewed from the drawing side of the mold. Therefore, the side wall portion 17 of the outer peripheral portion 16 of the coil spring 13 is caught by the mold and the mold cannot be removed. Therefore, in the second embodiment of the present invention, the shape of the coil spring 13 is formed so that the mold can be pulled out in two directions.

FIG. 5 is an explanatory view when the coil spring 13 according to the second embodiment of the present invention is molded by a molding machine, and FIG. 5A is a perspective view of the coil spring 13 according to the second embodiment of the present invention, and FIG. ) Is a cross-sectional view taken along line ZZ in FIG. FIG. 5 shows a case where the outer ring 14 and the coil spring 13 are integrally formed.

As shown in FIGS. 5 (a) and 5 (b), the coil spring 13 of the second embodiment of the present invention has a straight portion and a spiral portion (oblique portion), as shown in FIG. 5 (a). Further, a cross section taken along the line ZZ in the direction perpendicular to the linear portion of the coil spring 13 is taken, and in that cross section, the coil spring 13 is formed so that the front is wide and the back is narrow as viewed from the drawing side of the mold. The Therefore, even if the mold is slid in the two directions of the arrow A1 direction and the arrow A2 direction, the side wall portion 17 of the outer peripheral portion 16 of the coil spring 13 is not caught by the mold.

Thus, the coil spring 13 according to the second embodiment of the present invention has a straight portion and a spiral portion (an oblique portion), and the outer peripheral portion 16 of the coil spring 13 has a trapezoidal cross-sectional shape. And in the cross section of the orthogonal part of the linear part of the coil spring 13, the coil spring 13 is formed so that the front is wide and the back is narrow as viewed from the drawing side of the mold, so that the side wall of the outer peripheral part 16 of the coil spring 13 The portion 17 is not caught by the mold. Accordingly, the mold size of the coil spring 13 can be reduced, and molding with a small molding machine is possible, so that the mold cost and the product unit price can be suppressed.

2A and 2B, each of the springs 13a to 13d has a straight portion and a spiral portion (oblique portion). The arrangement of the springs 13a to 13d is the same as in the first embodiment shown in FIG. The other end is fixed to the connecting portion 15. Hereinafter, the second spring 13b, the third spring 13c, and the fourth spring 13d are also fitted in contact with the outer peripheral surface of the inner ring member 12, one end is not fixed, and the other end is It is fixed to the connecting portion 15.
Thus, in the second embodiment of the present invention, the coil spring 13 is formed by four one-turn springs 13a to 13d. The coil spring 13 has a straight portion and a spiral portion (an oblique portion). The outer peripheral portion 16 of the coil spring 13 has a trapezoidal cross section. The front side is wide and the back side is narrow as viewed from the drawing side of the mold. Thereby, the mold can be pulled out in two directions.

FIG. 3 is a configuration diagram of an example of a torque limiter unit according to the third embodiment of the present invention. The torque limiter unit of this example is obtained by mounting a shaft 18 on the torque limiter 11 shown in FIG. A torque limiter unit is formed by penetrating the shaft 18 through the inner ring member 12 formed in a cylindrical shape with resin. The shaft 18 is connected to the inner ring member 12 by engaging a shaft connecting portion 19 provided on the shaft 18 with a shaft connecting groove portion 12 </ b> A provided on the inner surface of the inner ring member 12.

3 shows the torque limiter unit in which the shaft 18 is attached to the torque limiter 11 of the first embodiment shown in FIG. 1, but the shaft 18 is attached to the torque limiter 11 shown in the second embodiment shown in FIG. A torque limiter unit may be formed by mounting.

FIG. 4 is a configuration diagram of another example of the torque limiter unit according to the third embodiment of the present invention. In another example of the torque limiter unit, a rotating roller member 20 is additionally attached to the outer ring member 14 of the torque limiter 11 with respect to the torque limiter unit shown in FIG. The same elements as those in FIG. 3 are denoted by the same reference numerals, and redundant description is omitted.

Rotating roller member 20 is attached to torque limiter 11 of this torque limiter unit. The roller portion 21 of the rotating roller member 20 is, for example, a rubber roller that continuously feeds cut sheets from a sheet stock of a copying machine.

4 shows the torque limiter unit in which the shaft 18 is attached to the torque limiter 11 of the first embodiment shown in FIG. 1, but the shaft 18 is attached to the torque limiter 11 of the second embodiment shown in FIG. May be.

Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ... Torque limiter, 12 ... Inner ring member, 12A ... Shaft connection groove part, 13 ... Coil spring, 14 ... Outer ring member, 15 ... Connection part, 16 ... Outer peripheral part, 17 ... Side wall part, 18 ... Shaft, 19 ... Shaft connection part, 20 ... Rotating roller member, 21 ... Roller part

Claims

A cylindrical inner ring member made of resin;
A coil spring that is formed by connecting a plurality of one-turn springs and is fitted in contact with the outer peripheral surface of the inner ring member;
An outer ring member holding one end of the coil spring;
When the torque between the inner ring member and the outer ring member is a predetermined value or less, the coil spring does not slip and torque is transmitted between the inner ring member and the outer ring member, and the inner ring member and the outer ring member A torque limiter characterized in that when the torque between them exceeds a predetermined value, the coil spring slips to interrupt torque transmission between the inner ring member and the outer ring member.
The torque limiter according to claim 1, wherein the coil spring has a shape in which a mold can be pulled out in two directions.
The torque limiter according to claim 1 or 2,
A torque limiter unit comprising: a shaft provided through the inner ring member of the torque limiter and connected to the inner ring member.
The torque limiter unit according to claim 3, wherein a rotating roller member is attached to the outer ring member of the torque limiter.