JPH05296259A - Torque limiter - Google Patents

Abstract

PURPOSE:To facilitate assembling of a torque limiter that uses a coil spring and enhance the position stability of the coil spring. CONSTITUTION:A large diameter cylindrical face 5 and a small diameter cylindrical face 6 are formed in the outer periphery of a spring connecting tube 4 provided at the end wall 2 of an outer tube member 1. The outside diameter of the small diameter cylindrical face 6 is roughly the same as that of an inner ring 10 inserted into an outer tube member 1. The small diameter coil portion 21 of a coil spring 20 is held in interference fit with the outside of the spring connecting tube 4 and the outside diameter coil portion 22 of the coil spring 20 is held in interference fit with the inside of the cylindrical portion 32 of a lid body 30 attached to the open end portion of the outer tube member 1. The coil spring 20, the outer tube member 1, the coil spring 20 and the lid body 10 are connected to one another by fitting so as to facilitate assembling of a torque limiter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant torque load applied to a rubber roller in a paper feeding section or a paper separating section of an office automation equipment such as a copying machine, a facsimile machine, a laser beam printer or the like, or a back of a drawing section of continuous paper. The present invention relates to a torque limiter used for tension or the like.

[0002]

2. Description of the Related Art As shown in FIG. 5, a large-diameter coil portion 43 and a small-diameter coil portion 44 are provided on a coil spring 42 provided outside an inner ring 41, and the small-diameter coil portion 44 allows the inner ring 41 to be formed.
The inner ring 4 in the direction to rewind the coil spring 42.
1 is rotated 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 and the small diameter coil portion 44 are rotated. The outer cylinder member 45 by causing a slip between
The torque limiter, which cuts off the transmission of torque to, is characterized by its simplicity and low cost.

In the above torque limiter,
Rotate the lid 46 attached to the open end of the outer cylinder member 45,
The torque setting value is adjusted by adjusting the binding force with which the small-diameter coil portion 44 tightens the inner ring 41.

[0004]

By the way, in the above torque limiter, the hooks 4 are provided at both ends of the coil spring 42.
7 and 48 are formed, the hook 47 on the large-diameter coil portion 43 side is engaged with the engaging hole 49 provided in the lid body 46, and the small-diameter coil portion 4 is formed.
Since the hook 48 on the fourth side is engaged with the engagement hole 51 formed in the end wall 50 of the outer tubular member 45, there is a problem that assembly is difficult.

Further, when the torque set value for rotating the lid 46 is adjusted, a rotational moment also acts on the coil spring 42, and the posture of the coil spring 42 collapses, causing a problem that torque fluctuation easily occurs.

It is a technical object of the present invention to solve the above problems, to facilitate the assembly of the torque limiter, and to improve the posture stability of the coil spring.

[0007]

In order to solve the above-mentioned problems, in the present invention, a lid is attached to the open end of the outer cylinder member, and the coil spring is twisted by the rotation of the lid. In a torque limiter for adjusting a binding force by which a small-diameter coil section tightens an outer-diameter surface of an inner ring, a smaller-diameter coil section, which is larger than the outer diameter of the inner ring, is connected to an end wall of the outer tubular member by a close-fitting fit. A spring connecting cylinder is provided, a cylindrical portion is formed on the one lid, and a large-diameter coil portion of the coil spring is connected to the inner diameter surface of the cylindrical portion with an interference fit.

In order to suppress the torque fluctuation due to the inconsistency of the axial center of the spring connecting cylinder and the inner ring, a small diameter cylindrical surface having a diameter substantially the same as the outer diameter of the inner ring is formed on the outer periphery of the tip of the spring connecting cylinder. Of.

[0009]

According to the present invention, as described above, the spring connecting cylinder is formed on the end wall of the outer cylindrical member, the cover is provided with the cylindrical portion, and both ends of the coil spring are tightly fitted to the spring connecting cylinder and the cylindrical portion. As a result, the assembly is easy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIGS. 1 and 3, the torque limiter according to the present invention comprises an outer cylinder member 1, an inner ring 10, a coil spring 20 and a lid 30.

The outer cylinder member 1 is open at one end, and an engaging groove 2 is provided on the inner circumference of the opening. Further, an end wall 3 is formed at the other end of the outer cylinder member 1, and a spring connecting cylinder 4 is formed on the end wall 3.
Is provided. A large-diameter cylindrical surface 5 and a small-diameter cylindrical surface 6 are provided on the outer circumference of the spring connecting cylinder 4, and the outer diameter of the small-diameter cylindrical surface 6 is substantially the same as the outer diameter of the inner ring 10.

The inner ring 10 is inserted inside the outer tubular member 1 from the open end. A shaft (not shown) is inserted inside the inner ring 10, and the inner ring 10 is rotated by the rotation of the shaft. In order to transmit the rotation of the shaft to the inner ring 10, a notch 11 is provided at an end portion of the inner ring 10 located outside the outer tubular member 1.
A pin provided on the shaft is engaged with the notch 11.

The coil spring 20 has a small diameter coil portion 21 and a large diameter coil portion 22, and the small diameter coil portion 21 is the inner ring 10.
And it is tightly fitted on the outer side of the spring connection cylinder 4.

The lid body 30 is incorporated inside the opening end of the outer cylinder member 1, and the ridge 31 formed on the outer diameter surface is engaged with the engagement groove 2. A cylindrical portion 32 is provided on the inner surface of the lid body 30, and the end portion of the large-diameter coil portion 22 is tightly fitted inside the cylindrical portion 32. Further, on the outer surface of the lid body 30,
A wrench engagement hole 33 for rotating the lid body 30 is provided.

Now, in the case where a left-handed coil spring is used as the coil spring 20, the inner ring 10 is shown in FIG.
When rotating counterclockwise as indicated by the arrow, the small-diameter coil portion 21 of the coil spring 20 and the inner ring 10 are tightly fitted together, so that the rotation of the inner ring 10 is transmitted to the outer tubular member 1 via the coil spring 20.

When the load acting on the outer cylinder member 1 is increased, the coil spring 20 is expanded in diameter by contact with the inner ring 10, and the binding force for tightening the inner ring 10 of the small-diameter coil portion 21 is gradually reduced. When the frictional force acting on the part is balanced, slippage occurs and the inner ring 10 spins.

If the tightening force for tightening the inner ring 10 of the small-diameter coil portion 21 is larger than the tightening force for tightening the spring connecting cylinder 4, slipping may occur between the fit-connecting cylinder 4 and the small-diameter coil portion 21. However, the spring coupling cylinder 4 has a large-diameter cylindrical surface 5 that is larger than the outer diameter of the inner ring 10.
Since the binding force of the coil spring 20 at is larger than the binding force of the coil spring 20 at the outer circumference of the inner ring 10, slippage does not occur between the large-diameter cylindrical surface 5 and the small-diameter coil portion 21, and the inner ring 10 and the small-diameter coil portion are not slipped. It is possible to surely cause slippage at the contact portion of 10.

As shown in FIG. 2, an inclined surface 7 is formed on the inner surface of the end wall 3 of the outer tubular member 1, and a step 8 corresponding to the wire diameter of the coil spring 20 is provided. Since the coil spring 20 is prevented from rotating with respect to the outer tubular member 1 by engaging the end faces of the above, the slip between the large-diameter cylindrical surface 5 and the small-diameter coil portion 21 can be reliably prevented. You can

When adjusting the torque setting value, the lid 30 is rotated with the outer cylinder member 1 fixed. Now lid 3
When 0 is rotated in the direction of the arrow shown in FIG.
Since 1 is prevented from rotating by the binding force that tightens the large-diameter cylindrical surface 5, the coil spring 20 is rotated by the rotation of the lid body 30.
Is twisted and expands in diameter. At this time, since the large-diameter coil portion 22 strongly contacts the inner surface of the cylindrical portion 32, the lid body 30 and the large-diameter coil portion 22 do not slip, while the small-diameter coil portion 21 tightens the inner ring 10 by its expanded diameter. The force is reduced, and the torque setting value can be reduced. On the contrary, when the lid body 30 is rotated in the opposite direction, the large-diameter coil portion 2
The force to reduce the diameter of 2 acts, and it will slip.
That is, the small-diameter coil portion 21 has a structure in which a tightening force higher than the initial design is not applied.

At the time of adjusting the torque set value as described above, since the large-diameter coil portion 22 is tightly fitted in the cylindrical portion 32 of the lid body 30, the rotational force of the lid body 30 is applied to the coil spring 20 as a couple. Therefore, the posture of the coil spring 20 does not collapse.

The large-diameter coil portion 22 is entirely cylindrical.
When it is tightly fitted in 2, the rotational displacement of the large-diameter coil portion 22 due to the rotation of the lid body 30 is directly transmitted to the small-diameter coil portion 21 and delicate adjustment becomes difficult.
Since the end portion is fitted into the cylindrical portion 32, the rotation of the lid body 30 can be absorbed by the large-diameter coil portion 22, and as a result, the torque setting value can be finely adjusted.

When assembling the torque limiter, the small-diameter coil portion 21 is fitted into the spring connecting cylinder 4, and the large-diameter coil portion 2 is attached.
After fitting 2 into the cylindrical portion 32 and press-fitting the lid 30 inside the opening of the outer tubular member 1, the inner ring 10 is inserted inside the lid 30, and the tip of the inner ring 10 in the insertion direction is a small-diameter coil. It is press-fitted inside the part 21.

When assembling the torque limiter as described above,
As shown in FIG. 4A, when the outer diameter of the spring connecting cylinder 4 is the same throughout the axial direction and the outer diameter is larger than the outer diameter of the inner ring 10, a coil spring is provided outside the spring connecting cylinder 4. When the small-diameter coil portion 21 of 20 is press-fitted, a displacement e ₁ occurs in the axial center between the portion where the small-diameter coil portion 21 is fitted to the spring coupling cylinder 4 and the portion where it is not fitted. In that state, as shown in FIG. 4B, the inner ring 10 is attached to the small-diameter coil portion 21.
When fitting the deviation of both the axis is not small in the same displacement in the axial e ₂ occurs in the spring coupling tube 4 and the inner ring 10, rise to the torque fluctuation by displacement of its axis, performance There is a problem of lowering.

However, in the present invention, a large-diameter cylindrical surface 5 and a small-diameter cylindrical surface 6 are provided on the outer periphery of the spring connecting cylinder 4, and the outer diameter of the small-diameter cylindrical surface 6 is made substantially the same as the outer diameter of the inner ring 10. Therefore, the deviation of the axial center between the spring coupling cylinder 4 and the inner ring 10 is extremely small, and a high-performance torque limiter with small torque fluctuation can be obtained.

[0026]

As described above, in the torque limiter according to the present invention, the small-diameter coil portion of the coil spring is fitted on the outside of the spring connecting cylinder to connect the coil spring and the outer cylinder member to each other. Since the lid is connected, the assembly of the torque limiter is extremely easy.

Further, since the end portion of the large-diameter coil portion is inserted into the cylindrical portion of the lid body, the rotation of the lid body can be absorbed in the portion of the large-diameter coil portion which is not fitted to the cylindrical portion, and the torque setting value can be set. It can be subtly adjusted.

Further, since the rotation of the lid is transmitted to the coil spring at the fitting portion between the spring connecting cylinder and the large-diameter coil portion, the posture of the coil spring does not collapse and it is possible to prevent torque fluctuation during torque transmission. it can.

Further, a large-diameter cylindrical surface and a small-diameter cylindrical surface are provided on the outer circumference of the spring connecting cylinder, and the outer diameter of the small-diameter cylindrical surface is made substantially equal to the outer diameter of the inner ring, so that the coil spring is coaxial with the inner ring. It is possible to provide a high-performance torque limiter with extremely small torque fluctuation.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a torque limiter according to the present invention.

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

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

4A and 4B 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 4 Spring connection cylinder 6 Small diameter cylindrical surface 10 Inner ring 20 Coil spring 21 Small diameter coil part 22 Large diameter coil part 30 Lid body 32 Cylindrical part

Claims (2)

[Claims] 1. A small-diameter coil portion for assembling a coil spring between an outer cylinder member and an inner ring provided inside the outer spring member, and a large-diameter coil portion having a diameter larger than that of the coil spring, the small-diameter coil portion having a smaller diameter. The 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 rotation of the lid adjusts the binding force with which the small diameter coil part tightens the inner ring. In the torque limiter for adjusting the torque setting value, the end wall of the outer tubular member is larger than the outer diameter of the inner ring,
A spring connecting cylinder is provided to connect the small-diameter coil section with a close-fitting fit.On the other hand, a cylindrical section is formed on the lid, and the large-diameter coil section of the coil spring is fitted to the inner diameter surface of the cylindrical section by a close-fitting fit. A torque limiter characterized by being connected together. 2. The torque limiter according to claim 1, wherein a small diameter cylindrical surface having a diameter substantially the same as the outer diameter of the inner ring is provided on the outer circumference of the tip end portion of the spring coupling cylinder.