JPH07174160A - One-way torque limiter - Google Patents

Abstract

PURPOSE:To enable adjustment of torque from the outside by positioning an elastic tube and a shaft fixing member in an outer tube between an outer tube end wall and a cover, engaging a coil spring with the outer tube and the cover in the peripheral surface of the elastic tube, and setting rotational direction frictional force of the cover larger than torsional force of the coil spring. CONSTITUTION:In the case of forwardly rotating a shaft 27 in a direction of winding a coil spring 4 tightened, when a load acting in a gear 29 is a preset torque value or less, torque of the shaft 27 is transmitted through a shaft fixing member 3, elastic tube 2, coil spring 4 and an outer tube 1. When exceeding the torque value, the coil spring 4 and the elastic tube 2 are slipped, to interrput torque. When the torque value is changed, a jig is inserted to an adjusting small recessed part 19 of a cover 5, to rotate it. When turned in a direction of winding the coil spring 4 tightened, a small diameter part 22 is diameterically contracted to diametrically contract the elastic tube 2, and frictional force therebetween is highly generated to increase the torque value. When the cover 5 is rotated in a reverse direction, the torque value is decreased. In the case of reversing the shaft 27, it is raced because of small tightening force against the elastic tube 2 of the coil spring 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to transmission of rotational torque,
Regarding a one-way torque limiter for shutting off, it is used in a paper transport section of an office machine.

[0002]

2. Description of the Related Art In a paper carrying section of an office machine, it acts as a torque limiter in the paper carrying direction, but in the opposite direction, it runs idle so that the paper can be pulled out when a paper jam occurs. A one-way torque limiter is used.

[0003]

In the above-described one-way torque limiter, when the conventional torque limiter is assembled, the torque value cannot be adjusted from the outside, so that the predetermined torque value cannot be obtained after the assembling. Had the inconvenience of having to disassemble it, adjust it, and then reassemble it.

Therefore, an object of the present invention is to make it possible to appropriately adjust the torque value from the outside in the one-way torque limiter.

[0005]

In order to solve the above-mentioned problems, the present invention accommodates an elastic cylinder coaxial with the outer cylinder and a shaft fixing member engaged with one end of the outer cylinder inside the outer cylinder. Then, the elastic cylinder and the shaft fixing member are axially positioned between the end wall of one end of the outer cylinder and the lid fitted to the open end of the other end, and tightened on the outer peripheral surface of the elastic cylinder. One end of the coil spring is fitted to the outer cylinder, the other end is engaged with the lid, and the frictional force in the rotation direction of the lid is set to be large by the twisting force of the coil spring.

[0006]

In the one-way torque limiter having the above-described 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 becomes large and exceeds a predetermined constant torque value, slip occurs between the elastic cylinder and the coil spring, and the torque transmission is interrupted.

When adjusting the above torque value, a force larger than the twisting force of the coil spring is applied to the lid from the outside. When the force is rotated in the winding direction of the coil spring, the tightening force on the elastic cylinder is increased, so that the torque value is increased and when it is rotated in the opposite direction, it is decreased.

When the load side reverses, the tightening force of the coil spring with respect to the elastic cylinder decreases, the outer cylinder idles, and the function of the torque limiter is lost.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 3, a one-way torque limiter according to an embodiment has an outer cylinder 1, an elastic cylinder 2, a shaft fixing member 3,
It is composed of a coil spring 4 and a lid 5.

One end of the outer cylinder 1 is open, and a fitting groove 6 for the lid 5 is formed on the inner peripheral surface of the open end. An end wall 7 is provided at the other end of the outer cylinder 1, and a shaft insertion hole 8 is provided in the central portion of the end wall 7. On the outer surface of the end wall 7, the shaft insertion hole 8
A pair of engaging protrusions 9 are provided around the.

The elastic tube 2 is made of elastic metal or synthetic resin and is formed in a cylindrical shape having a C-shaped cross section. The elastic cylinder 2 has a slit 11 in the axial direction and is formed to have a diameter larger than that of the shaft insertion hole 8. Further, engaging recesses 12 are provided on one end of the slit 11 on the shaft fixing member 3 side and on the opposite side thereof.

In the elastic cylinder 2, when an inward force is applied from the outer peripheral surface of the elastic cylinder 2, the slit 11 becomes narrower and elastically contracts. The elastic cylinder 2 is assembled inside the outer cylinder 1 coaxially with the outer cylinder 1 and pressed against the inner surface of the end wall 7 of the outer cylinder 1.

The shaft fixing member 3 is formed so that its inner diameter is the same as that of the shaft insertion hole 8 and its outer diameter is divided into a large diameter portion 13 and a small diameter portion 14, and a step is formed between both portions 13, 14. Part 15 is present. Further, a pair of engagement protrusions 16 is provided at the end on the large diameter portion 13 side, and a pair of engagement recesses 17 is provided at the end on the small diameter portion 14 side.

The shaft fixing member 3 is coaxially housed inside the outer cylinder 1, and the engaging projection 16 thereof is fitted into the engaging recess 12 of the elastic cylinder 2 to allow the rear end of the elastic cylinder 2 to move. Contact the end face. The rear end portion of the small diameter portion 14 of the shaft fixing member 3 is the outer cylinder 1.
From the open end of the.

The lid 5 is inserted into the outer diameter surface of the small-diameter portion 14 of the shaft fixing member 3 with a slight clearance, and the outer diameter surface of the lid 5 is press-fitted into the inner diameter surface of the opening of the outer cylinder 1 so that the lid The rib 18 formed on the outer diameter surface of the groove 5 fits in the fitting groove 6.

The coil spring 4 is formed by tightly winding a square wire, and comprises a small diameter portion 22 and a large diameter portion 23 continuous with the small diameter portion 22.
Hooks 24 and 25 are provided on the small diameter portion 22 and the large diameter portion 23, respectively. The small diameter portion 22 is tightened to the outer diameter surface of the elastic cylinder 2. The large diameter portion 23 is fitted around the large diameter portion 13 of the shaft fixing member 3 with a gap. The side hooks 24 of the small diameter portion 22 are engaged holes 2 formed on the inner surface of the end wall 7 of the outer cylinder 1.
6 and the hook 25 of the large diameter portion 23 is inserted into the engaging hole 21 of the lid 5.

The lid 5 is brought into contact with the step portion 15 of the shaft fixing member 3 and thereby positions the shaft fixing member 3 and the elastic cylinder 2 in the axial direction. A plurality of torque adjusting small recesses 19 are provided on the outer surface of the lid 5. Further, an engagement hole 21 for the coil spring 4 is provided on the inner surface thereof.

The lid 5 receives the twisting force of the coil spring 4, but the frictional force between the outer diameter surface of the lid 5 and the inner diameter surface of the outer cylinder 1 is set to be larger than the torque due to the above-mentioned twisting force. Therefore, it is prevented from rotating freely.

When the torque value is adjusted, the lid 5 is rotated by inserting a jig into the adjustment small recess 19 on the outer surface thereof, so that the frictional force is within a range in which it can be rotated for adjustment. Is set.

The one-way torque limiter of the embodiment is constructed as described above, and when the shaft 27 rotates in the winding tightening direction of the coil spring 4, the frictional force generated between the small diameter portion 22 and the elastic cylinder 2 is reduced. The magnitude determines the torque value.

The projection 28 of the shaft 27 is fitted and fixed in the engagement recess 17 of the shaft fixing member 3, and the end wall 7 of the outer cylinder 1 is fixed.
A rotation transmitting member such as a gear 29 is mounted on the shaft 27 protruding from the shaft 27, and the engagement protrusion 9 of the outer cylinder 1 is fitted and fixed to the gear 29.

When the shaft 27 normally rotates in the winding direction of the coil spring 4 and the magnitude of the load acting through the gear 29 is equal to or less than a preset torque value, the torque of the shaft 27 is the torque of the shaft fixing member. 3 is transmitted through the elastic cylinder 2, the coil spring 4, and the outer cylinder 1.

When the magnitude of the load exceeds a preset torque value, a slip occurs between the coil spring 4 and the elastic cylinder 2, and the torque transmission is interrupted.

When it becomes necessary to change the torque value, an appropriate jig is inserted into the adjusting small recess 19 of the lid 5, and the lid 5 is rotated. At this time, when the coil spring 4 is turned in the tightening direction, the diameter of the small diameter portion 14 is reduced and the diameter of the elastic cylinder 2 is reduced. Therefore, the frictional force between them becomes large and the torque value becomes high.
When the lid 5 is rotated in the opposite direction, the torque value becomes low.

On the other hand, when the shaft 27 reverses, the tightening force of the coil spring 4 against the elastic cylinder 2 is small, so that the shaft 27 idles.

By filling a lubricant between the inner diameter surface of the outer cylinder 1 and the outer diameter surfaces of the elastic cylinder 2 and the shaft fixing member 3, maintenance can be made free.

[0027]

As described above, in the torque limiter of the present invention, the torque can be adjusted by operating the lid of the outer cylinder, so that the torque value can be appropriately adjusted from the outside even after assembly or during use. There is convenience.

[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 Elastic cylinder 3 Shaft fixing member 4 Coil spring 5 Lid 6 Fitting groove 7 End wall 8 Shaft insertion hole 9 Engagement protrusion 11 Slit 12 Engagement recess 13 Large diameter part 14 Small diameter part 15 Step part 16 Engagement Protrusion 17 Engagement recess 18 Rib 19 Small recess 21 Engagement hole 22 Small diameter part 23 Large diameter part 24, 25 Hook 26 Engagement hole 27 Shaft 28 Protrusion 29 Gear

Claims (1)

[Claims] 1. An elastic cylinder coaxial with the elastic cylinder and a shaft fixing member engaged with one end of the outer cylinder are housed inside the outer cylinder, and the elastic cylinder and the shaft fixing member are provided at one end of the outer cylinder. Position axially between the end wall and the lid fitted to the open end of the other end,
One end of the coil spring tightened on the outer peripheral surface of the elastic cylinder is fitted to the outer cylinder and the other end is engaged with the lid, and the frictional force in the rotation direction of the lid is made larger than the twisting force of the coil spring. One-way torque limiter set.