JPH09291946A - Tow-way torque limiter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a torque fluctuation due to irregular operation of a roller when deficiency in interference of the roller occurs owing to the occurrence of unevenness in an elastic deformation amount of the diameter of an outer ring. SOLUTION: A pair of wedge-form spaces 15a and 15b having a narrow direction being reverse are formed in a plurality of pockets 11 formed at the inside diameter surface of an outer ring 1 and rollers 3 are contained in the wedge-form spaces 15a and 15b. An elastic body 17 to exert a press force in the narrow directions of the wedge-form spaces 15a and 15b is located. Roller regulation pieces 18 and 18' to hold a distance between the rollers 3 on both sides of a partition wall at a value higher than a constant value are movably in a peripheral direction between partition walls 12, 12a, and 12b between the pockets 11 and an inner ring 2. The roller 3 deficient in interference is pressed by the elastic body 17 and the reaction force thereof is exerted on the intrusion part of the other roller 3 through the regulation pieces 18 and 18'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional torque limiter.

[0002]

2. Description of the Related Art As a bidirectional torque limiter capable of setting a large torque in both forward and reverse rotation directions, the present applicant has already filed a patent application in Japanese Patent Application No. 7-39820 and a further improved version thereof. A patent application has been filed in Japanese Patent No. 7-252860.

The structure common to the bidirectional torque limiters of the above two applications is such that the inner ring is inserted through the inner diameter side of the outer ring which is elastically deformable in the radial direction, and the required number of pockets separated by partition walls are formed on the inner diameter surface of the outer ring. A pair of wedge-shaped spaces are provided on the bottom surface of each pocket so that the distance between the pocket and the outer diameter surface of the inner ring becomes small in both the forward and reverse rotation directions, and the rollers are housed in the wedge-shaped spaces with a required tightening margin.

In the above-described bidirectional torque limiter, when either the inner ring or the outer ring is normally or reversely rotated, the roller bites into the wedge-shaped space to be in the locked state and transmits the torque. Then, when a load larger than a certain amount is applied, the roller hits the partition wall of the pocket and slips, whereby the lock is released and the inner ring or the outer ring idles.

[0005]

In the bidirectional torque limiter as described above, a structure in which a notch is provided at one position in the circumferential direction of the outer ring is adopted as means for enabling elastic deformation of the outer ring in the radial direction. However, with such a structure, the amount of elastic deformation becomes uneven between the portion near the cut and the portion away from the cut, and therefore some of the plurality of rollers have insufficient tightening margins. is there.

When one of the inner ring and the outer ring rotates in such a state, the roller with insufficient tightening margin does not lock, so that the degree of freedom increases, and irregular movement such as skewing occurs, and the torque limiter does not operate. It causes the transmission torque to fluctuate.

In order to solve the above-mentioned problems, the improved bidirectional torque limiter (Japanese Patent Application No. 7-252860) has O-rings fitted so as to circumscribe all rollers arranged in an annular shape. The elastic force of the ring presses each roller against the outer diameter surface of the inner ring to regulate the irregular movement of the roller.

As mentioned above, the method using the O-ring is also one effective means, but in view of the fact that the life of the O-ring is not sufficient, the present invention uses the restraint means other than the O-ring to cause the irregular movement of the roller. It is an object of the present invention to provide a bidirectional torque limiter that regulates the torque.

[0009]

In order to achieve the above object, the invention of claim 1 inserts an inner ring into an inner diameter side of an outer ring which is elastically deformable in the radial direction, and separates the inner ring surface of the outer ring by a partition wall. Providing a required number of pockets provided, a pair of wedge-shaped spaces with a smaller distance between the inner ring outer diameter surface in both the forward and reverse rotation directions on the bottom of each pocket, each roller is housed in each wedge-shaped space, An elastic body that exerts a pressing force on each roller in the narrow direction of the wedge-shaped space is interposed between the rollers in each pocket, and is present on both sides of the partition between the partition between the pockets of the outer ring and the inner ring. The roller restricting piece for keeping the interval between the rollers at a certain level or more is movably interposed in the circumferential direction.

According to a second aspect of the present invention, the outer ring has a circumferential direction of 1
A cut is provided at each position, and the cut allows the outer ring to be elastically deformed in the radial direction.

According to a third aspect of the present invention, an elastic adjustment ring is fitted on the outer diameter surface of the outer ring, and a pair of protrusions provided on the cut of the outer ring is fitted inside the cut provided on the adjustment ring. A taper surface having a taper angle in the axial direction is formed on the cut ring of the adjustment ring and the opposing surface of each protrusion, and a moving means for relatively moving the adjustment ring in the axial direction is provided.

According to a fourth aspect of the present invention, in any one of the above-mentioned aspects, the surface hardness Hv of those rollers is 900 or more and the surface roughness Ra is 0.04 μm or less.

The upper limit of the surface hardness is about 1800 from the viewpoint of processing difficulty. The smoother the surface roughness, the more desirable it is, and therefore it is not limited. However, for example, about 0.01 μm can sufficiently achieve the object of the invention.

[0014]

In the bidirectional torque limiter having the above structure, when a load is applied to the outer ring to rotate the inner ring in one direction, one roller in each pocket bites into one wedge space and enters a locked state, and torque is transmitted to the outer ring. To be done. At this time, the other roller in each pocket does not lock and does not contribute to torque transmission. That is, one roller in one pocket locks but the other roller does not.

The roller of the portion of the outer ring having a large diameter expansion may not be locked as it is because of insufficient tightening margin.
The elastic body in contact with the roller exerts a pressing force in the narrow direction of the wedge-shaped space to lock it.

When the roller moves in the narrow direction of the wedge-shaped space, the roller pushes and moves the roller regulating piece in the moving direction and presses the roller in an adjacent pocket which is not locked. As a result, the roller that is not in the locked state is constrained between the rear regulating piece and the front elastic body, and irregular movement is regulated.

When the load acting on the outer ring exceeds a certain level, the roller hits the partition wall of the pocket and stops biting, so that the inner ring idles.

When the inner ring is rotated in the opposite direction, the other roller of each pocket bites into the other wedge-shaped space, and the same operation as described above is performed.

Further, contrary to the above, when the load is applied to the inner ring and the outer ring is rotated in either forward or reverse direction, the same operation as above is performed.

When the roller having the surface hardness and the surface roughness as described in claim 4 is used, the roller is less likely to be unevenly worn, and the action of the roller to wear the inner ring and the outer ring is reduced, so that the sliding state is stabilized. , Durability is improved.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIGS. 1 and 2,
The bidirectional torque limiter of this embodiment includes an inner ring 2 coaxially inserted on the inner diameter side of an outer ring 1, a plurality of rollers 3 interposed therebetween, an adjusting ring 4 fitted on the outer periphery of the outer ring 1, and a casing 5. And a lid 6 of the casing 5 and the like.

The inner ring 2 has a cylindrical shape, and the shaft 10 is inserted therein. The inner ring 2 and the shaft 10 are the inner ring 2
The notch 7 formed in the above and the pin 8 protruding from the shaft 10 are integrated with each other.

The outer ring 1 is made of an elastic material such as metal and has a radial cut 9 at one circumferential position. The outer ring 1 can be elastically deformed in the diameter expanding or contracting direction due to the presence of the cut 9.

A plurality of pockets 11 are provided on the inner diameter surface of the outer ring 1.
Is formed, and each pocket 11 is separated by a partition 12 (in the portion of the cut 9 described above, the cut 9 and the partition walls 12a and 12b divided on both sides).

A land portion 13 slightly rising from the bottom surface is formed in the central portion of each pocket 11 in the circumferential direction of the outer ring 1, and the bottom surface of the pocket 11 extending from both sides of the land portion 13 to both partition walls 12 or 12a, 12b. The first sloped surface 14a and the second sloped surface 14b are formed on the respective surfaces.
These inclined surfaces 14a, 14b are high on the land 13 side with respect to the outer diameter surface of the inner ring 2, and the partition walls 12, 12
The a and 12b sides are formed low. Each inclined surface 14a, 14
A first wedge-shaped space 15a and a second wedge-shaped space 15b are formed between b and the outer diameter surface of the inner ring 2.

The rollers 3 are incorporated in the first wedge-shaped space 15a and the second wedge-shaped space 15b of each pocket 11, respectively. That is, the pair of rollers 3 is incorporated in the pocket 11 at one place. The inclination angles of the inclined surfaces 14a and 14b forming the wedge-shaped spaces 15a and 15b are the same as those of the rollers 3
Is formed in a size that causes a locking action when the bite penetrates into the wedge-shaped spaces 15a and 15b.

The inner surfaces of the wedge-shaped spaces 15a, 15b on the partition walls 12, 12a, 12b side are a first stopper surface 16a and a second stopper surface 16b, respectively, and the stopper surfaces 16a, 16b are the outer ring 1 respectively. It has a function of stopping the biting of the roller 3 within the range of elastic deformation.

Between the land portion 13 of each pocket 11 and the outer diameter surface of the inner ring 2, each wedge-shaped space 15a,
An elastic body 1 formed of spring pieces having an S-shape when viewed from the outer peripheral direction of the outer ring 1 between the rollers 3 incorporated in 15b.
7 is interposed (see FIG. 2 (b)), thereby applying an elastic force in opposite circumferential directions to the rollers 3 on both sides thereof.

Further, each of the above-mentioned partition walls 12, 12a, 12b.
And the outer diameter surface of the inner ring 2, the plate-shaped roller restricting piece 18 having a width across both sides of the partition wall 12 (in the cut 9 portion, both sides including the break 9 and the partition walls 12a and 12b on both sides thereof). , 18 'are interposed.

The side edges of the roller restricting pieces 18, 18 'approach the adjacent rollers 3 of both adjacent pockets 11, and when either one of the rollers 3 moves in the circumferential direction, it is pushed by that roller 3. It freely moves in the circumferential direction and is pressed against the other roller 3.

The adjusting ring 4 is made of an elastic material such as metal and is fitted around the outer ring 1 with a required space. A radial cut 19 is provided at one position in the circumferential direction of the adjusting ring 4 to allow elastic deformation in the radial direction.

A pair of projections 21 protruding in the radial direction from the cut 9 of the outer ring 1 are respectively opposed to the opposed surfaces of the cuts 19, and the opposed surfaces of the projections 21 and the cuts 19 are axially opposed to each other. Taper surface 22 having the same taper angle,
23 is formed (see FIG. 3).

The outer ring 1, the inner ring 2, the rollers 3 and the adjusting ring 4 are assembled in a casing 5. Casing 5
Has one end open, and a shaft hole 25 is formed in the closing wall 24 at the other end.

On the inner surface side of the closing wall 24, the first and second wedge-shaped spaces 15a and 15b of each pocket 11 of the outer ring 1 are formed.
A plurality of protrusions 26 (see FIG. 2) to be fitted into the ends of the pockets 11 are formed, and the protrusions 26 and the partition walls 12, 12 of the pocket 11 are formed.
By engaging with a and 12b, torque is transmitted between the outer ring 1 and the casing 5. A spring 27 is housed between the inner surface of the closing wall 24 and the adjusting ring 4, and an engaging protrusion 28 that engages with an external member to transmit torque is formed on the outer surface of the closing wall 24. .

The lid 6 is fitted around the inner ring 2 with a slight gap, and a rib 29 is formed on the outer diameter surface thereof.

The rib 29 is fitted into the fitting groove 31 of the casing 5.
It is fitted with a slight tightening allowance (a tightening allowance that can be rotated with a certain amount of force after installation).

As shown in FIG. 4, on the inner surface of the lid 6, a pressing surface 33 for the roller 3 and the outer ring 1 is formed around the shaft hole 32. An inclined surface 34 having an inclination angle of is provided in three equal positions.

On the end face of the adjusting ring 4 on the lid side, there are provided projections 35 opposed to the inclined surfaces 34, and the projections 35 are pressed against the inclined surfaces 34 by the pressing force of the spring 27.

The bidirectional torque limiter of the embodiment is as described above, and its operation will be described below. Now, with the protrusion 35 of the adjustment ring 4 in contact with the lower position of the inclined surface 34 of the lid 6, there is a sufficiently large gap between the tapered surfaces 22 and 23 and between the outer ring 1 and the adjustment ring 4. However, it is assumed that interference does not occur even if the outer ring 1 is expanded to the maximum diameter.

Therefore, in FIG. 1, the inner ring 2 is indicated by an arrow A in the figure.
When it is rotated in the direction, the roller 3 in the first wedge-shaped space 15a moves in the rotation direction to expand the outer ring 1 and bite into the first wedge-shaped space 15a to perform a locking action. 1 rotates together with the inner ring 2 and torque is transmitted to the casing 5.

In this case, even if there is a roller 3 that does not lock in the first wedge-shaped space 15a as it is because the tightening margin is insufficient due to the difference in the expanded diameter of the outer ring 1, the rollers in each first wedge-shaped space 15a are present. All 3 are pressed in the narrow direction of the wedge-shaped space by the elastic force of the elastic body 17, and thus perform a locking action. Further, the roller regulating piece 1 is moved by the movement of the roller 3.
8, 18 'is pushed and moved, and its roller regulating piece 18,
18 'pushes the roller 3 in the second wedge-shaped space 14b of the other pocket 11 which is adjacent in the direction of movement,
Is pressed against the elastic body 17.

Such an action occurs in a chain in the circumferential direction, and the reaction force from the roller 3 acting on each elastic body 17 is transmitted through the other roller 3 and the roller restricting pieces 18, 18 'to ensure the reliability. It is supported by any one of the other rollers 3 which is biting.

When the load acting on the outer ring 1 through the casing 5 increases while the torque is being transmitted as described above, the outer ring 1 as shown by the one-dot chain line in FIG.
The cut 9 of the roller spreads and the biting amount of the roller 3 increases,
When the load is further increased, the roller 3 comes into contact with the stopper surface 16a of the first wedge-shaped space 15a, and the biting of the roller 3 into the first wedge-shaped space 15a is stopped. As a result, the locking action of the roller 3 is lost, and it is not possible to support a load higher than that, and the inner ring 2 idles.

On the other hand, when the inner ring 2 is rotated in the opposite direction to the above, the roller 3 in the second wedge-shaped space 15b of each pocket 11 performs a locking action and performs the same action as described above.

That is, the roller 3 is rotated in both forward and reverse directions.
Serves as a torque limiter that transmits torque within a range in which it comes into contact with the stopper surfaces 16a and 16b and causes idling when the torque is larger than that.

In the above, the case where the torque is transmitted from the inner ring 2 to the outer ring 1 has been described.

When the lid 6 is rotated from the outside and the adjusting ring 4 is pushed in by the inclined surface 34, the tapered surfaces 22, 2 are formed.
The gap of 3 becomes small, or it adheres. As a result, when the outer ring 1 is expanded in diameter by the movement of the roller 3, the adjustment ring 4 is also expanded, and the total force of both is applied to the roller 3, so that a large torque can be transmitted.

As is apparent from the above description, the torque limiter of the present invention uses the outer ring 1 and the adjusting ring 4 as spring members at the time of overload, and the roller 3 is strongly pressed against the inner ring 2 so A large friction torque is obtained by sliding the inner ring 2.

The required function of the torque limiter is to rotate with a torque within the standard at the time of overload. Therefore, in order to improve the durability, it is necessary to stabilize the sliding state.

In the torque limiter described above, the spring force changes depending on the amount of deformation of the outer ring 1 and the adjusting ring 4, so that when the sliding parts of the outer ring 1, the inner ring 2 and the rollers 3 wear, the amount of deformation of the outer ring 1 decreases, and the spring The power becomes smaller. As a result, the rotational torque at the time of overload decreases, and it is necessary to suppress wear of each sliding portion in order to improve durability.

In order to meet such requirements, the surface hardness of the roller 3 is Hv900 or more and the surface roughness Ra is 0.0.
It is necessary that the thickness be 4 μm or less. As the material of the roller 3, steel whose hardness is increased by heat treatment, steel whose surface is hard-plated, cemented carbide or ceramic is used. The upper limit of surface hardness is Hv1 considering the difficulty of processing.
Set to 800.

The surface roughness of the roller 3 is 0.04 μm or less by grinding or lapping. It is desirable that the surface is smooth. For example, it may be about 0.01 μm.

[Test Results] FIG. 6A shows the results of the durability test of the torque limiter, and FIG. 6B shows the results of the comparative tests. The surface hardness and surface roughness of the roller in these cases are
As shown in the figure.

[0054]

As described above, according to the bidirectional torque limiter of the present invention, rollers are incorporated in a pair of wedge-shaped spaces having narrow directions opposite to each other, an elastic body is interposed between the rollers, and the rollers are adjacent to each other. Even if there is a roller that has a non-uniform tightening due to the diameter expansion of the outer ring due to the interposition of a roller regulating piece between the adjacent rollers between the pockets, the elasticity of such roller is The presence of the roller restricting piece as a body and force transmitting member makes it possible to restrict the movement of the roller. As a result, it is possible to prevent the torque fluctuation due to the irregular operation of the roller and to achieve a stable function as a torque limiter.

Further, by increasing the surface hardness of the roller and decreasing the surface roughness, uneven wear of the roller and wear of the inner and outer rings are suppressed, and durability is improved. Also, even under severe operating conditions that could not be dealt with so far, the torque can be stabilized when overloaded, and the usable range can be expanded.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment.

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

FIG. 3 is a partially cutaway plan view of the above.

FIG. 4 is a partially exploded perspective view of the same.

FIG. 5 is a partially enlarged sectional view of the above.

FIG. 6A is a graph of a durability test. FIG. 6B is a graph of a durability test of a comparative example.

[Explanation of symbols]

 1 Outer ring 2 Inner ring 3 Roller 4 Adjustment ring 5 Casing 6 Lid 7 Notch 8 Pin 9 Cut 10 Shaft 11 Pocket 12 Partition 12a, 12b Partition 13 Land part 14a First inclined surface 14b Second inclined surface 15a First wedge-shaped space 15b Second wedge-shaped space 16a First stopper surface 16b Second stopper surface 17 Elastic body 18, 18 'Roller regulation piece 19 Cut 21 Protrusion 22 Tapered surface 23 Tapered surface 24 Closing wall 25 Shaft hole 26 Projection 27 Spring 28 Engagement projection 29 rib 31 fitting groove 32 shaft hole 33 pressing surface 34 inclined surface 35 protrusion

Claims (4)

[Claims] 1. An inner ring is inserted through an inner diameter side of an outer ring that is elastically deformable in the radial direction, and a required number of pockets separated by a partition wall are provided on the inner diameter surface of the outer ring. A pair of wedge-shaped spaces with a small distance from the outer diameter surface of the inner ring are provided, the rollers are housed in the wedge-shaped spaces, and the rollers are placed between the rollers in the pockets in the narrow direction of the wedge-shaped space. A roller regulating piece for maintaining a certain distance or more between the rollers existing on both sides of the partition between the partition between the pockets of the outer ring and the inner ring is provided in the circumferential direction with an elastic body exerting a pressing force interposed. A bidirectional torque limiter that is movably interposed. 2. The bidirectional torque limiter according to claim 1, wherein a cut is provided at one position in the circumferential direction of the outer ring, and the outer ring is elastically deformable in the radial direction by the cut. 3. An elastic adjustment ring is fitted on the outer diameter surface of the outer ring, and a pair of protrusions provided on the cut of the outer ring is fitted inside the cut provided on the adjustment ring, and the cut of the adjustment ring is formed. 3. A taper surface having a taper angle in the axial direction is formed on the facing surface of each protrusion, and a moving means for relatively moving the adjustment ring in the axial direction is provided.
Bidirectional torque limiter described in. 4. The roller has a surface hardness Hv900 or more,
The bidirectional torque limiter according to any one of claims 1 to 3, wherein the surface roughness Ra is 0.04 µm or less.