JP3494276B2 - Torque limiter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter for limiting a load torque associated with rotation transmitted in one direction or two directions to a set value or less.

[0002]

2. Description of the Related Art Generally, in a paper feeding device of an electronic information device such as a copying machine, a printer, or a facsimile device, a bidirectional torque limiter is provided in a paper double feeding prevention mechanism to prevent double feeding of paper. At the same time, in the case of a paper jam, the paper feeding mechanism can be reversed to easily remove the jammed paper.

As a torque limiter having a structure in which the frictional force between the coil spring and the inner ring changes significantly due to expansion and contraction, there is a torque limiter disclosed in Japanese Patent Application Laid-Open No. 8-270675.
The torque limiter has a structure as shown in FIG. 5, and will be described according to the description of the publication.

An outer ring 2 is provided outside the inner ring 1. The outer ring 2 is open at one end and closed at the other end. An insertion hole 4 is provided on the inner surface of the closed end wall 3, and a shaft insertion hole 5 is provided on the bottom surface of the insertion hole 4.

The inner ring 1 is rotatably supported by inserting one end into the insertion hole 4, and the other end is rotatably supported by a ring-shaped lid 6 attached to the opening of the outer ring 2.

Here, the lid 6 is rotatably attached to the outer ring 2 and is prevented from rotating by a frictional force acting on a contact portion with the outer ring 2.

The coil spring 7 incorporated between the inner ring 1 and the outer ring 2 has a small diameter coil portion 7 at the end of the large diameter coil portion 7a.
b are arranged in series, and the small-diameter coil portion 7b clamps the outer surface of the inner ring 1.

Large diameter coil portion 7a and small diameter coil portion 7
Bending pieces 8 and 9 are provided at each end of b. One bent piece 8 is engaged with an engagement piece 10 formed on the inner surface of the lid body 6, and the other bent piece 9 is engaged with an engagement hole 11 provided on the inner surface of the closed end wall 3 of the outer ring 2. It has been stopped.

Grease is filled between the inner ring 1 and the outer ring 2, and the grease lubricates the contact portion between the inner ring 1 and the coil spring 7. A shaft 12 is inserted inside the inner ring 1, and a pin 13 provided on the shaft 12 engages with a notch portion 14 formed at the other end of the inner ring 1, and the engagement prevents the inner ring 1 from rotating on the shaft 12. It

A small-diameter shaft portion 15 is provided on one end surface of the inner ring 1, and a first oil sump 16 is provided between one end surface of the inner ring 1 and the bottom surface of the insertion hole 4 on the outer periphery of the small-diameter shaft portion 15. There is.

Further, the shaft 1 is attached to one end of the inner diameter surface of the inner ring 1.
Large-diameter hole portion 1 that forms a second oil sump 17 between the two outer surfaces
8 are provided. This second oil sump 17 is for preventing grease from leaking to the outside only with the first oil sump 16, and this application has a point in which the second oil sump 17 is provided.

[0012]

However, in the torque limiter having such a structure, since the grease leaks to the outside only by the first oil sump, which has been performed before this application, the second oil sump is removed. It had to be provided and had a complicated structure.

Even if the second oil sump is provided, if the second oil sump is filled with grease, there is still a problem that the grease leaks to the outside. Therefore, the second oil sump should be sufficiently large. It has the drawback of having to.

In the bidirectional torque limiter using the coil spring, the coil spring moves bidirectionally on the inner ring surface, so that the first and second oil sumps must be provided on the lid side as well. Further complicating the structure.

An object of the present invention is to provide a torque limiter that solves the conventional problem of lubricant leakage and can prevent lubricant leakage with an extremely simple structure.

[0016]

[Means for Solving the Problems] In order to solve the above-mentioned problems, a first aspect of the present invention is directed to a coil spring provided to generate a frictional force between an inner ring and an outer surface of the inner ring, and the coil spring. An outer ring having a locking portion that can lock the end of the outer ring, and a lid that is locked to the outer ring, and lubricates the gap between the inner ring where the coil spring is located and the inner wall of the outer ring. In a torque limiter containing the agent, the inner wall of the side wall of the lid in the gap formed between the inner ring and the outer ring is provided with an annular taper portion having an inclined surface where the inner ring side is thick and the outer ring side is thin. A torque limiter is provided.

In order to solve the above problems, the second aspect of the present invention is that in the first aspect, an oil sump is provided between the inner ring and the lid body to prevent the lubricant from leaking. A characteristic torque limiter is provided.

In order to solve the above-mentioned problems, the third aspect of the invention is to lock an inner ring and a coil spring provided to generate a frictional force between the outer surface of the inner ring and an end portion of the coil spring. An outer ring having a lockable portion and a lid that is locked to the outer ring, and a lubricant is enclosed in a space between the inner ring where the coil spring is located and the inner wall of the outer ring. In the torque limiter, an inner surface of the closed end wall portion of the outer ring in a gap formed between the inner ring and the outer ring includes an annular taper portion having an inclined surface that is thicker on the inner ring side and thinner on the outer ring side. A torque limiter is provided.

In order to solve the above-mentioned problems, the fourth aspect is that in the third aspect, an oil sump is provided between the inner ring and the closed end wall portion of the outer ring to prevent leakage of the lubricant. The present invention provides a torque limiter characterized by being provided.

In order to solve the above problems, claim 5 is claim 1 or claim 2 and claim 3 or claim 4
The present invention provides a torque limiter, which is a combination of the above descriptions.

In order to solve the above-mentioned problems, claim 6 is the method according to any one of claims 1 to 5.
The torque limiter is characterized in that the angle of the inclined surface is 75 ° or less with respect to the surface of the inner ring.

In order to solve the above-mentioned problems, claim 7 is the method according to any one of claims 1 to 6,
The torque limiter is characterized in that the inclination of the inclined surface is substantially linear.

In order to solve the above-mentioned problems, claim 8 is defined by any one of claims 1 to 6.
The torque limiter is characterized in that the slope of the inclined surface is curved in either direction.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION First, a mode for carrying out the invention will be described with reference to FIGS. 1 and 2. 1 and 2, the same symbols as those shown in FIG. 5 indicate corresponding members.

The feature of the present invention resides in that, as shown in FIG. 1 or 2, a part of the closed end wall portion 3 of the outer ring 2 and / or the inner wall of the lid body 6 has an inclined cross section. Especially inner ring 1
In the space S surrounded by the outer ring 2 and the outer ring 2, the closed end wall part 3 or / and the lid 6 of the outer ring 2 is closed on the annular taper part 3a such that the inner ring 1 side is thicker and the outer ring 2 side is thinner. 3 and the annular taper portion 6a is formed on the lid body 6.

The cross section of the inclined surface of the annular tapered portion 3a of the closed end wall portion 3 and the inclined surface of the annular tapered portion 6a of the lid body 6 is preferably a linear inclination, but a curved shape on either side is almost linear inclination. It has been confirmed from various experiments that a similar effect is obtained, and that the inclination angle θ is 75 ° or less with respect to the surface of the inner ring 1 is practically useful.

With such a structure, during the operation of the torque limiter, the coil spring 7 is moved between the inner ring 1 and the outer ring 2 by moving the surface of the inner ring 1 left and right in the drawing due to the expansion / contraction diameter movement. Even if the lubricant filled in the space S flows in the left-right direction in the drawing, the lubricant in the annular taper portion 3a of the closed end wall portion 3 and the annular taper portion 6a of the lid 6 follows the inclination of the outer ring. 2 In order to flow to the inner surface side,
It is considered that the amount of leakage to the oil sump 16 or 16 ′ through the gap between the inner ring 1 and the closed end wall portion 3 or the lid 6 is extremely small.

In this embodiment, the oil sump 16 or 16 ′ is provided between the inner ring 1 and the closed end wall portion 3 or the lid 6, but the oil sump 16 or 16 ′ is selected by selecting a lubricant. It can be omitted.

Next, an embodiment will be described with reference to FIG. The inner ring 1 has a slightly thicker wall thickness at the central portion 1b as compared with the wall pressures at both ends 1a, 1a. Therefore, the central portion 1b has a slightly larger outer diameter than both end portions 1a, 1a. large. An oil sump 16 is formed between the lid 6 and a portion from the central portion 1b to the end 1a, and an oil sump 16 'is formed between the end 1a and the closed end wall portion 3 of the outer ring 2. These oil pools provide a large space S as compared with the space formed between the inner ring 1 and the closed end wall portion 3 or the lid body 6.

A coil spring 7 is attached to the outer diameter surface of the central portion 1b of the inner ring 1 so as to apply an appropriate pressing force. Then, the hooks 7a and 7b of the coil spring 7 are locked to the locking cutouts 2a and 2b, which serve as the locking portions of the outer ring 2, respectively.
The hooks 7a and 7b of the coil spring 7 are formed by bending both ends of the winding wire at a certain angle with respect to an outer surface of a cylinder of which the contour is defined by the winding wire of the coil spring 7, and projecting the outer ring. It is easy to be locked by the two locking notches 2a and 2b. The locking notches 2a and 2b extend in the winding direction of the coil spring 7 and have a structure in which a larger amount of a lubricant L described later is enclosed.

The inner diameter of the outer ring 2 is larger than the outer diameter of the central portion 1b of the inner ring 1, and the space S between the coil spring 7 attached to the central portion 1b of the inner ring 1 and the inner wall of the outer ring 2 is large.
Exists in the space S, and a lubricant L such as grease that stabilizes the slip between the inner ring 1 and the coil spring 7 is present.
Is filled. Then, the lid 6 is fitted to the outer ring 2 to obtain a single torque limiter.

What is important here is that the inner wall surface of the lid 6 has an annular taper portion 6a, as is clear from the above description. Since the annular taper portion 6a has the shape described with reference to FIG. 1, it will not be described in detail, but in the space S between the inner ring 1 and the outer ring 2, the inner peripheral portion of the central opening into which the inner ring 1 enters is thickest, It has a shape that becomes thinner outward with an inclination of 75 ° or less.

Since a torque limiter in which the inner ring 1, the outer ring 2 and the coil spring 7 are combined is widely known, a detailed description of the operation will be omitted, but the closed end wall portion 3 of the inner ring 1 and the outer ring 2 or the lid. A narrow gap exists between the body 6 and the body 6 so as not to hinder the mutual rotation. During operation of the torque limiter, the coil spring 7 expands and contracts in the left-right direction in the drawing by an operation of tightening and loosening the central portion 1b of the inner ring 1, that is, an expanding / contracting diameter operation.

In this embodiment, when the coil spring 7 spreads in the left-right direction, the closed end wall portion 3 and the lid 6 are covered with the coil spring 7.
Acts as a stopper so that it does not spread further in the left-right direction. When the coil spring 7 spreads in the left-right direction,
Since the lubricant filled in the space S receives a force in the extending direction of the inner ring 1 which is the axial direction, the lubricant tends to leak to the outside through a minute gap between the inner ring 1 and the lid 6.

However, in this torque limiter, the lid 6
Since each of the inner wall surfaces of the annular taper portion 6a has an annular taper portion 6a, the lubricant acting on the annular taper portion 6a as the coil spring 7 expands in the left-right direction has an annular taper portion 6a.
It is considered that due to the inclination of, the fluid flows to the outer ring 2 side with almost no flow in the direction of the minute gap between the annular taper portion 6a and the inner ring 1.

This is because unlike the alcohol and water, the lubricant has a sufficiently large viscosity as compared with them, so that almost all of the lubricant flows in the same direction due to the mutual viscosities. This is considered to be one of the reasons why the amount of lubricant flowing to the oil sump 1B through the gap between the lid 6 and the lid 6 is significantly reduced.

According to various experiments, very good results have been obtained without forming a complicated structure or adding a separate member. According to the experiment, the effect increases as the angle θ (FIG. 1 (B)) of the annular taper portion 6a of the lid 6 decreases from 90 °, but if the angle θ is too small, the height of the annular taper portion 6a increases. Since the torque limiter becomes wider and the cost becomes higher, the angle is preferably about 45 ° or more and 75 ° or less in consideration of the effect of the invention, but is not limited to this range.

FIG. 4 is a diagram showing a second embodiment of this torque limiter, and the same symbols as those in FIG. 3 indicate the corresponding members. This embodiment differs from the embodiment shown in FIG. 3 in that not only the lid 6 is provided with an annular taper portion 6a, but also the closed end wall portion 3 of the outer ring 2 is provided with a similar annular taper portion 3a. Is characterized by. The shape, function, etc. of the annular taper portion 3a are the same as those of the annular taper portion 6a of the lid body 6, and therefore description thereof will be omitted.

In the above-mentioned embodiments, the unidirectional torque limiter composed of a single coil has been described. However, a unidirectional torque limiter in which two or more coil springs are coupled in series can be implemented in exactly the same manner. As shown in the example,
The same effect can be obtained with a bidirectional torque limiter in which two or more coil springs screwed in opposite directions are connected in series.

The coil spring 7 may have approximately one turn to any number of turns, and the winding of the coil spring may have any elasticity, for example, various types from wide to round.

[0041]

As described above, the lid body serving as the end wall,
Since the inner wall surface of the closed end wall portion of the outer ring has a shape with an annular taper portion, the amount of lubricant leaked to the outside through the gap between the inner ring, the lid, and the closed end wall portion of the outer ring is significantly suppressed. Therefore, it is not necessary to provide the oil sump in a two-stage manner, and by selecting a lubricant, a torque limiter that does not require an oil sump can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a torque limiter according to the present invention.

FIG. 2 is a diagram showing a second embodiment of a torque limiter according to the present invention.

FIG. 3 is a diagram showing a first embodiment of a torque limiter according to the present invention.

FIG. 4 is a diagram showing a second embodiment of the torque limiter according to the present invention.

FIG. 5 is a diagram for explaining a conventional torque limiter.

[Explanation of symbols]

1 ... inner ring 6 ... lids 1a, 1a ... small diameter end portion of inner ring 7 ... coil spring 1b ... large diameter central portion 7a, 7b of inner ring 1
・ Coil spring hook 2 ... Outer ring 16, 16 '
··· Oil sumps 2a, 2b ··· Notch for locking S ··· Space 3 · · · Closed end wall

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16D 7/02

Claims (8)

(57) [Claims] 1. An outer ring having a coil spring provided so as to generate a frictional force between an inner ring and an outer surface of the inner ring, an outer ring having a locking portion capable of locking an end of the coil spring, and the outer ring. And a lid body that is locked to the inner ring of the outer ring, and a lubricant is filled in a gap between the inner ring where the coil spring is located and the inner wall of the outer ring. The torque limiter is characterized in that the inner surface of the side wall of the lid in the gap is provided with an annular taper portion having an inclined surface that is thicker on the inner ring side and thinner on the outer ring side. 2. The torque limiter according to claim 1, further comprising an oil sump between the inner ring and the lid to prevent the lubricant from leaking. 3. An inner ring and a coil spring provided so as to generate a frictional force between the inner ring and the outer surface of the inner ring, an outer ring provided with a locking portion capable of locking an end of the coil spring, and the outer ring. In a torque limiter having a lid body locked to the inner ring of the outer ring and the inner ring in which the coil spring is located, a space between the inner ring and the outer ring. A torque limiter, characterized in that an inner surface of the closed end wall portion of the outer ring in the formed gap has an annular taper portion having an inclined surface that is thicker on the inner ring side and thinner on the outer ring side. 4. The torque limiter according to claim 3, further comprising an oil sump between the inner ring and the closed end wall portion of the outer ring for preventing the lubricant from leaking out. 5. A torque limiter, characterized in that the combination of claim 1 or claim 2 and claim 3 or claim 4 is combined. 6. The angle according to claim 1, wherein the angle of the inclined surface is 75 ° with respect to the surface of the inner ring.
A torque limiter characterized in that: 7. The torque limiter according to any one of claims 1 to 6, wherein the inclination of the inclined surface is substantially linear. 8. The torque limiter according to any one of claims 1 to 6, wherein the inclination of the inclined surface is curved in either direction.