JPH0637628U - Torque limiter - Google Patents

Abstract

(57) [Abstract] [Purpose] To facilitate the assembly of a torque limiter using a coil spring and shorten the overall length to make it compact. [Structure] A large diameter cylindrical surface 9 and a small diameter cylindrical surface 10 are formed on the outer periphery of a spring connecting cylinder 8 provided on an end wall 7 of the outer cylindrical member 1, and the outer diameter of the small diameter cylindrical surface 10 is set inside the outer cylindrical member 1. The outer diameter of the inner ring 2 inserted into the inner ring is approximately the same as the outer diameter. The small-diameter coil portion 4 of the coil spring 3 is tightly fitted to the outside of the spring coupling cylinder 8, and the large-diameter coil portion 5 of the coil spring 3 is abutted against the protrusion 12 of the lid 6 attached to the open end of the outer cylinder member 1. Contact. The protruding portion 12 is formed from a part of a cylinder having about 1/8 of the entire circumference, and the large-diameter coil portion 5 has about 1 turn.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a torque limiter used for a rotary shaft of OA equipment and other various equipment.

[0002]

[Prior art]

 The torque limiter is used to apply a constant torque to the rubber roller of the paper feed section and the paper separation section of OA equipment such as copiers, facsimiles, and laser beam printers, or to back tension the continuous paper pull-in section. . An example of a torque limiter used for such a purpose is shown in FIG.

As shown in the figure, a large-diameter coil portion 43 and a small-diameter coil portion 44 are provided on a coil spring 42 provided outside the inner ring 41, and the inner ring 41 is tightened by the small-diameter coil portion 44 to wind the coil spring 42. When the inner ring 41 is rotated in the returning direction and the rotational force is transmitted to the outer cylinder member 45 via the coil spring 42, and when the load acting on the outer cylinder member 45 exceeds a preset torque limiter value, the inner ring 41 is rotated. The torque limiter that causes a slip between the small diameter coil portion 41 and the small diameter coil portion 44 to cut off the transmission of torque to the outer cylinder member 45 is simple and low in cost.

In the torque limiter as described above, the lid 46 mounted on the open end of the outer tubular member 45 is rotated, and the small diameter coil portion 44 adjusts the binding force with which the inner ring 41 is tightened. I am trying to make adjustments. 47 and 48 are hooks, 49 and 51 are engaging holes, and 50 is an end wall.

[0005]

[Problems to be solved by the device]

 By the way, the coil spring of the conventional torque limiter is composed of a large-diameter coil portion and a small-diameter coil portion as described above, which makes the elastic coefficient of the spring different and facilitates the adjustment of the torque setting value. There is.

However, since the large diameter portion of the spring, which is the torque adjusting portion, is long, there is a problem in that the entire length of the main body becomes long.

Further, since the hooks at both ends of the coil spring are engaged with the engaging holes provided in the lid body and the end wall to prevent rotation, there is a problem that assembly is difficult. As a method for solving this, a small diameter is used. On the coil side, a boss that is a tight fit to the inner diameter of the small diameter coil is formed on the end wall side and engaged with this.The large diameter coil side forms a cylindrical portion inside the lid, and the inner diameter of the cylindrical portion A method is considered in which they are engaged by interference fit.

However, in this method, if the large-diameter portion of the spring is tightly fitted within the inner diameter of the cylindrical portion of the lid, torque fluctuation may occur when the spring is restrained while tilted.

In consideration of the above-mentioned problems of the conventional torque limiter, the present invention facilitates assembly without engaging in the coil springs and causing torque fluctuations, and the large diameter portion of the coil springs is used. It is an object of the present invention to provide a torque limiter configuration that is short and has a short overall length.

[0010]

[Means for Solving the Problems]

 As a means for solving the above problems, the present invention is directed to a coil spring inserted between an outer cylinder member and an inner ring provided inside thereof, the coil spring comprising a small-diameter coil portion for tightening the inner ring and a large-diameter coil having a larger diameter. The small-diameter coil part is connected to the outer cylinder member, the large-diameter coil part is connected to the lid attached to the open end of the outer cylinder member, and the small-diameter coil part tightens the inner ring by the rotation of the lid. In the torque limiter that adjusts the force to adjust the torque setting value, a spring-connected cylinder in which the coil part that is larger than the outer diameter of the inner ring and is smaller than the outer diameter of the inner ring is connected to the inner rear end wall of the outer cylinder member by interference fit. Of the torque limiter, in which the large-diameter coil portion is provided for approximately one turn, and a protrusion formed by a part of the circumference is formed on the inner side of the lid body to press the large-diameter coil portion in the radial direction on the inner diameter side. It was a composition.

[0011]

[Action]

 According to the torque limiter of the present invention having the above-mentioned structure, one end of the coil spring is fitted and connected to the spring connecting cylinder, and the other end has the large-diameter coil portion in contact with the protruding portion, so that the assembly is easy and the entire length is long. Is getting shorter.

Since one coil of the large-diameter coil portion in which the coil spring is expanded is pressed in the radial direction inside the protrusion formed on the lid, a torque is applied by applying a radial load to the spring. By rotating the lid and changing the position of the protrusion, the radial load applied to the spring is changed to adjust the applied torque. This facilitates assembly without torque fluctuations.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 3, the torque limiter according to the present invention comprises an outer cylinder member 1, an inner ring 2, a coil spring 3 and a lid 6.

The outer tubular member 1 is open at one end, and an engaging groove 1a is provided on the inner circumference of the opening. An end wall 7 is formed at the other inner end of the outer cylinder member 1, and a spring connecting cylinder 8 is provided on the end wall 7. A large-diameter cylindrical surface 9 and a small-diameter cylindrical surface 10 are provided on the outer periphery of the spring connecting cylinder 8, and the outer diameter of the small-diameter cylindrical surface 10 is substantially the same as the outer diameter of the inner ring 2.

The inner ring 2 is inserted inside the outer tubular member 1 from the open end. A shaft (not shown) is inserted inside the inner ring 2, and the inner ring 2 is rotated by the rotation of the shaft. In order to transmit the rotation of the shaft to the inner ring 2, a notch 11 is provided at an end of the inner ring 2 located outside the outer tubular member 1, and a pin provided on the shaft is engaged with the notch 11. There is.

The coil spring 3 has a small-diameter coil portion 4 and a large-diameter coil portion 5, and the small-diameter coil portion 4 is tightly fitted to the outer side of the inner ring 2 and the spring connecting cylinder 8.

The lid body 6 is incorporated inside the opening end of the outer cylinder member 1, and the protrusion 6b formed on the outer diameter surface is engaged with the engagement groove 1a. The inner surface of the lid body 6 is provided with a protrusion 12 that is formed of approximately 1/8 of the entire circumference, and the large-diameter coil portion 5 contacts the inside of the protrusion 12. The large-diameter coil portion 5 has approximately one turn. Further, the outer surface of the lid body 6 is provided with a wrench engagement hole 6a for rotating the lid body 6.

In this embodiment configured as described above, torque transmission is performed as follows.

When a left-handed coil spring is used as the coil spring 3, when the inner ring 2 is rotated counterclockwise as shown by the arrow in FIG. 1, the small-diameter coil portion 4 of the coil spring 3 and the inner ring 2 are tightly fitted. Therefore, the rotation of the inner ring 2 is transmitted to the outer tubular member 1 via the coil spring 3.

When the load acting on the outer cylinder member 1 is increased, the coil spring 3 is expanded due to the contact with the inner ring 2, and the binding force for tightening the inner ring 2 of the small-diameter coil portion 4 is gradually reduced. When the frictional force acting on that part and the frictional part are balanced, slippage occurs and the inner ring 2 spins.

At that time, if the binding force for tightening the inner ring 2 of the small-diameter coil portion 4 is larger than the binding force for tightening the spring connecting cylinder 8, slipping may occur between the spring connecting cylinder 8 and the small-diameter coil portion 4. However, in reality, the spring connecting cylinder 8 has a large-diameter cylindrical surface 9 larger than the outer diameter of the inner ring 2, and the binding force of the coil spring 3 on the large-diameter cylindrical surface 9 is the coil on the outer circumference of the inner ring 2. Since the binding force of the spring 3 is larger than the binding force of the spring 3, slippage does not occur between the large-diameter cylindrical surface 9 and the small-diameter coil portion 4, and slip can be surely produced at the contact portion between the inner ring 2 and the small-diameter coil portion 4. .

As for the end of the small-diameter coil portion 4, as shown in FIG. 2, a step corresponding to the wire diameter of the coil spring 3 is formed by forming an inclined surface 7 a on the inner surface of the end wall 7 of the outer tubular member 1. By providing 13 and engaging the end surface of the coil spring 3 with the step 13, the coil spring 3 is prevented from rotating with respect to the outer tubular member 1, so that the large-diameter cylindrical surface 9 and the small-diameter coil portion 4 are combined. It is possible to reliably prevent slippage between them.

In the torque transmitting action of the torque limiter, the inner diameter side of the protrusion 12 is outside the outer diameter of the small-diameter coil portion 4 of the coil spring, and is located inside the outer diameter of the large-diameter coil portion 5. Therefore, the large-diameter coil portion 5 of the coil spring can be pressed by the protrusion 12 in the radial direction, and a radial load can be applied to the coil spring.

Further, since the coil spring smoothly rises from the small-diameter coil portion 4 to the large-diameter coil portion 5 in approximately one turn, the large-diameter coil portion 5 is pressed in the radial direction on the protrusion 12 by the relative position in the circumferential direction. The force is different and the radial load applied to the coil spring can be changed.

Since the radial load is applied to the coil spring by the protrusion 12, it is possible to add a minute torque to the torque generated between the small-diameter coil portion 4 and the inner ring 2. By rotating the lid 6 with respect to the outer cylinder member 1 to change the position of the protrusion 12 and adjusting the additional torque, the overall torque can be finely adjusted.

The torque value of the present torque limiter is determined by the tightening margin between the inner ring 2 and the small diameter coil portion 4. The deviation from the set torque value at that time is compensated by adding torque by fine adjustment. The torque limiter basically has no adjusting mechanism, and only the additional torque is adjusted by changing the relative position of the protrusion 12 with respect to the large-diameter coil portion 5 by rotating the lid body 6.

Therefore, the torque limiter does not set the torque by rotating the lid 6 to expand the small-diameter coil portion 4 and reduce the binding force for tightening the inner ring 2. By adding a small torque obtained by applying a radial load to the large-diameter coil portion 5 to the torque value determined by the dimensions of the inner ring 2 and the small-diameter coil portion 4, a fine adjustment mechanism that compensates for the deviation from the set torque value is provided. It is something I had.

At the time of assembling the torque limiter, the small-diameter coil portion 4 is fitted into the spring connecting cylinder 8 and the large-diameter coil portion 5 is brought into contact with the projection 12 so that the lid body 6 is placed inside the opening of the outer cylinder member 1. After press-fitting, the inner ring 2 is inserted inside the lid 6, and the tip end of the inner ring 2 in the insertion direction is press-fitted inside the small-diameter coil part 4.

At the time of assembling the torque limiter as described above, as shown in FIG. 4A, the outer diameter of the spring coupling cylinder 8 is made the same throughout the entire axial direction, and the outer diameter is smaller than the outer diameter of the inner ring 2. In the case of a large size, when the small-diameter coil portion 4 of the coil spring 3 is press-fitted to the outside of the spring connecting cylinder 8, the small-diameter coil portion 4 is fitted into the spring connecting cylinder 8 and the shaft of the non-fitting portion. A misalignment e ₁ occurs. When the inner ring 2 is fitted into the small-diameter coil portion 4 in that state as shown in FIG. 4 (b), the axial centers of the two do not become the same, but the axial center of the spring coupling cylinder 8 and the axial center of the inner ring 2 are not the same. There is a case where the shift e ₂ occurs, and a torque fluctuation occurs due to the shift of the shaft center, which lowers the performance.

However, in this invention, a large-diameter cylindrical surface 9 and a small-diameter cylindrical surface 10 are provided on the outer periphery of the spring connecting cylinder 8, and the outer diameter of the small-diameter cylindrical surface 10 is made substantially the same as the outer diameter of the inner ring 2. Therefore, the deviation of the axial center between the spring connecting cylinder 8 and the inner ring 2 is extremely small, and a torque limiter with a small torque fluctuation and high performance can be obtained.

[0031]

[Effect of device]

 As described in detail above, the torque limiter of the present invention has a coil spring inserted between the outer cylinder member and the inner ring, one end of which is tightly fitted to the spring connecting cylinder and the other end of which is a large-diameter coil portion of approximately one turn. Since it is configured to abut on the protrusion inside the lid and hold it in the radial direction, it is easier to assemble than the conventional one, and the large-diameter coil part is shorter, so the total length of the torque limiter is shorter. it can.

In addition, since the end of the large-diameter coil portion of the coil spring is not restrained by the lid, the danger of the spring tilting due to the assembling method is avoided, and the external force applied to the spring can be released, which reduces torque fluctuations. .

Further, when the outer diameter of the large-diameter coil portion is not uniform, the torque adjustment may not be smoothly performed. However, since the large-diameter coil portion has approximately one turn, the torque adjustment can be performed more reliably. You will be able to do it.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a torque limiter.

FIG. 2 is a cross-sectional view showing a part of the above outer cylinder member.

FIG. 3 is an exploded perspective view of the above.

4 (a) and 4 (b) are views for explaining a problem that occurs when the spring connecting cylinder is made larger than the outer diameter of the inner ring.

FIG. 5 is a sectional view showing a conventional torque limiter.

[Explanation of symbols]

 1 Outer Cylinder Member 2 Inner Ring 3 Coil Spring 4 Small Diameter Coil Section 5 Large Diameter Coil Section 6 Lid 7 End Wall 8 Spring Connection Tube 9 Large Diameter Cylindrical Surface 10 Small Diameter Cylindrical Surface 12 Projection

Claims (1)

[Scope of utility model registration request] 1. A small-diameter coil, wherein a coil spring is inserted between an outer cylinder member and an inner ring provided inside thereof, and the coil spring comprises a small-diameter coil portion for tightening the inner ring and a large-diameter coil portion having a diameter larger than that. Part is connected to the outer cylinder member, the large-diameter coil part is connected to the lid attached to the open end of the outer cylinder member, and the small-diameter coil part adjusts the binding force to tighten the inner ring by the rotation of the lid, and the torque is adjusted. In the torque limiter for adjusting the set value, a spring coupling cylinder is provided on the inner end wall of the outer cylinder member, in which a small diameter coil portion having a diameter smaller than the outer diameter of the inner ring is coupled by interference fit, and a large diameter coil portion is provided. Is approximately one turn, and a protrusion formed of a part of the circumference is formed inside the lid, and the large diameter coil portion is pressed in the radial direction on the inner diameter side thereof.