JPH07174159A - Bidirectional torque limiter - Google Patents

Abstract

PURPOSE:To provide a bidirectional torque limiter easily mounted in compactness at a low cost. CONSTITUTION:An elastic tube 3 placed in a condition of contracting the diameter is inserted in an internal diameteric surface of an inner tube 2, to engage a shaft fixing member 4 with one end of the elastic tube 3, and the inner tube 2 of inserting the elastic tube 3 and the shaft fixing member 4 are stored in an outer tube 1, to provide an engaging surface of preventing relative rotation and a grease reservoir 14 in opposed surfaces between an external surface of the inner tube 2 and an internal surface of the outer tube 1. A grease circulating path 16 is provided between the grease reservoir 14 and the internal diametric surface of the inner tube 2, and a device is formed in a manner wherein the inner tube 2 of inserting the elastic tube 3 and the shaft fixing member 4 are positioned in the axial direction between an end wall 8 of the outer tube 1 and a cover 5 fitted to an opening end of this outer tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to transmission of rotational torque,
A bidirectional torque limiter for shutting off is used for driving a constant torque of an office machine.

[0002]

2. Description of the Related Art A bidirectional torque limiter used for driving a constant torque of an office machine is generally a powder type using a magnet or a friction plate type using a slip agent.

[0003]

The above-mentioned powder system has a high cost, and the friction plate system is difficult to unitize, so that there is a problem that the mounting work requires labor.

Therefore, an object of the present invention is to provide a bidirectional torque limiter which is inexpensive, compact and easy to mount.

[0005]

In order to solve the above-mentioned problems, the present invention inserts an elastic cylinder in a reduced diameter state into the inner diameter surface of an inner cylinder, and engages a shaft fixing member at one end of the elastic cylinder. Then, the inner cylinder and the shaft fixing member having the elastic cylinder inserted therein are housed in the outer cylinder in a coaxial state, the outer surface of the inner cylinder and the facing surface of the inner surface of the outer cylinder, an engagement surface for preventing relative rotation, A lubricant reservoir is provided, and a lubricant circulation path is provided between the lubricant reservoir and the inner cylinder inner diameter surface, and the inner cylinder and the shaft fixing member in which the elastic cylinder is inserted are attached to the end wall of the outer cylinder and its end. It is configured such that it is axially positioned between the lid fitted to the open end.

[0006]

In the bidirectional torque limiter having the above structure, torque is transmitted from the shaft fixed to the shaft fixing member to the load side via the gear fixed to the outer cylinder.

When the torque on the load side increases and exceeds a preset constant torque value, slip occurs between the elastic cylinder and the inner cylinder, and the torque transmission is interrupted.

When both the inner cylinder and the elastic cylinder are made of metal, a lubricant such as grease is filled in the lubricant reservoir for use. The lubricant is supplied to the inner diameter surface of the inner cylinder through the circulation path.

When the inner cylinder is made of metal and the elastic body is made of synthetic resin, the lubricity of the synthetic resin is utilized and no lubricant is used. The generated abrasion powder passes through the circulation path to reach the lubricant reservoir, where it is accumulated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the accompanying drawings, the bidirectional torque limiter of the embodiment comprises an outer cylinder 1, an inner cylinder 2, an elastic cylinder 3, a shaft fixing member 4 and a lid 5.

One end of the outer cylinder 1 is opened, an inner peripheral surface 6 for fitting the lid 5 and the shaft fixing member 4 is formed on the inner peripheral surface of the open end, and the lid 5 is fitted on the inner peripheral surface 6. The ditch 7 is formed.

An end wall 8 is provided at the other end of the outer cylinder 1, and a shaft insertion hole 9 is provided in the central portion of the end wall 8. Its end wall 8
A pair of engaging projections 11 is provided around the shaft insertion hole 9 on the outer surface of the.

The inner surface of the outer cylinder 1 between the inner peripheral surface 6 on the open end side and the end wall 8 is a circular arc surface 1 at three equal positions in the circumferential direction.
2 is formed, and a flat surface 13 is formed between the arcuate surfaces 12 to form a non-circular inner surface.

The outer peripheral surface of the inner cylinder 2 has a hexagonal shape, and three of the three surfaces fit exactly with the flat surface 13 of the outer cylinder 1 and are engaged with each other in the circumferential direction so that the outer cylinder 1 and the inner cylinder 2 are joined together. To prevent relative rotation with. Further, a grease reservoir 14 is formed between the circular arc surface 12 of the outer cylinder 1 and the three flat surfaces 13 of the inner cylinder 2.

The inner surface of the inner cylinder 2 is a cylindrical surface, and axial lubricating grooves 15 are provided at regular intervals in the circumferential direction. In the lubricating groove 15 at the position of the grease reservoir 14, both end portions penetrate to the outer surface,
Circulation path 1 for grease between the grease reservoir 14 and the inner peripheral surface
It is 6.

The elastic tube 3 is made of elastic metal or synthetic resin and is formed into a cylindrical shape having a C-shaped cross section. The elastic cylinder 3 has a slit 17 in the axial direction and is formed to have a diameter larger than that of the shaft insertion hole 9. Further, an engaging recess 18 is provided at one end of the slit 17 on the shaft fixing member 4 side and at a position symmetrical to the center thereof.

The elastic cylinder 3 is formed to have the same length as the inner cylinder 2 and is inserted into the inner peripheral surface of the elastic cylinder 3 in a state of being elastically reduced in diameter. The radial force exerted by the elastic cylinder 3 on the inner diameter surface of the inner cylinder 2 becomes the torque value of the torque limiter.

The shaft fixing member 4 has the same inner diameter as the shaft insertion hole 9 described above, and a collar 19 is formed on the outer peripheral surface of the inner end thereof.
The other end side projects to the outside of the outer cylinder 1. A pair of engagement projections 21 is provided at the end portion on the side of the collar 19 and one engagement recess 22 is provided at the other end.

The collar 19 is fitted on the inner peripheral surface of the outer cylinder 1 with a slight clearance. Further, the engaging projection 21 is engaged with the engaging recess 18 of the elastic cylinder 3, and the inner cylinder 2 and the elastic cylinder 3 integrated with the inner cylinder 2 are provided between the collar 19 and the end wall 8 of the outer cylinder 1. Performs axial positioning of.

The lid 5 is fitted to the outer diameter surface of the shaft fixing member 4 with a slight clearance, and the lid 5 presses the outer surface of the collar 19 and the ribs 23 on the outer peripheral surface of the lid 5 cover the outer cylinder 1. It is fitted and fixed in the fitting groove 7 of the inner peripheral surface 6.

By fitting the lid 5 as described above,
All the constituent members of the outer cylinder 1, the inner cylinder 2, the elastic cylinder 3, the shaft fixing member 4, and the lid 5 are integrated.

The bidirectional torque limiter of the embodiment is constructed as described above, and the projection 25 of the shaft 24 is fitted in the engaging recess 22 of the shaft fixing member 4 and the shaft 24 protruding from the end wall 8 of the outer cylinder 1 is provided. A rotation transmitting member such as a gear 26 is attached to the portion, and the engagement protrusion 11 of the outer cylinder 1 is fitted and fixed to the gear 26.

When the magnitude of the load acting through the gear 26 is equal to or less than a preset torque value when the shaft 24 is rotating in either forward or reverse directions, the torque of the shaft 24 is the torque of the shaft fixing member. 4, the elastic cylinder 3, the inner cylinder 2, and the outer cylinder 1 are transmitted. When the load magnitude exceeds a preset torque value, slip occurs between the elastic cylinder 3 and the inner cylinder 2,
The torque transmission is cut off.

When both the inner cylinder 2 and the elastic cylinder 3 are made of metal, grease is filled in the grease reservoir 14 in order to achieve lubrication between the contact surfaces of the both. The enclosed grease reaches the inner peripheral surface of the inner cylinder 2 through the circulation path 16 and is held in the lubrication groove 15 to perform a lubricating action.

If the inner cylinder 2 is made of metal and the elastic cylinder 3 is made of synthetic resin, the lubricity of the elastic cylinder 3 can be utilized, and no grease is used. The abrasion powder generated by the sliding contact between the inner cylinder 2 and the elastic cylinder 3 passes through the circulation path 16 and accumulates in the grease reservoir 14.

[0026]

As described above, the bidirectional torque limiter of the present invention has a small number of parts, is low in cost, and is easy to assemble. Further, since the respective parts are integrated, handling and mounting work become easy. Further, since it has a grease reservoir that communicates with the inner diameter surface of the inner cylinder, greasing work is unnecessary for a long period of time, and maintenance becomes easy. Further, when the elastic body is made of synthetic resin and is not lubricated, the grease reservoir serves as a reservoir for the abrasion powder, so that the trouble caused by the abrasion powder can be avoided.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a sectional view taken along line II-II of the above.

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

[Explanation of symbols]

 1 Outer Cylinder 2 Inner Cylinder 3 Elastic Cylinder 4 Shaft Fixing Member 5 Lid 6 Inner Circumferential Surface 7 Fitting Groove 8 End Wall 9 Shaft Insertion Hole 11 Engagement Protrusion 12 Arc Surface 13 Flat Surface 14 Grease Reservoir 15 Lubrication Groove 16 Circulation Path 17 Slit 18 Engagement recess 19 Collar 21 Engagement protrusion 22 Engagement recess 23 Rib 24 Shaft 25 Protrusion 26 Gear

Claims (1)

[Claims] 1. An elastic cylinder in a reduced diameter state is inserted into an inner diameter surface of the inner cylinder, a shaft fixing member is engaged with one end of the elastic cylinder, and the inner cylinder and the shaft fixing member into which the elastic cylinder is inserted are externally attached. Stored coaxially in the cylinder, on the opposite surface of the outer surface of the inner cylinder and the inner surface of the outer cylinder,
An engagement surface for preventing relative rotation and a lubricant reservoir are provided, a lubricant circulation path is provided between the lubricant reservoir and the inner diameter surface of the inner cylinder, and the inner cylinder into which the elastic cylinder is inserted and the shaft are fixed. Parts
A bidirectional torque limiter that is axially positioned between the end wall of the outer cylinder and the lid fitted to the open end thereof.