JPH0694053A - Torque limiter with automatic resetting function - Google Patents

Abstract

PURPOSE:To provide a torque limiter that is automatically reset at a long time CONSTITUTION:A cylindrical surface 5 is formed in an inner ring 1 and a polygonal engaging surface 9 in an outer ring 2 by square ring-form plate spring 8, respectively, and a roller 13 engaging with a minimum clearance part between both these cylindrical and engaging surfaces 5 and 9 is installed in a pocket of a retainer 11 installed in space between both these inner and outer rings 1 and 2. The retainer 11 is decentered in the radial direction by a bearing 16 attached to an eccentric surface 15 of the inner ring 1, and a circular part 20 of the retainer 11 is made contact with a circular part 19 installed in the outer ring 2. When load torque becomes larger in a state that the roller 13 is engaged, the plate spring 8 deforms to some extent, whereby the roller 13 passes through an engaging position and a clutch comes off. Next, the retainer 11 rotates as contacting with the circular part 19 of the outer ring 2 by dint of turning force out of the inner ring 1, producing a creep there, and thereby the roller is shifted up to the next engaging position at low speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter having a function of automatically returning.

[0002]

2. Description of the Related Art Conventionally, in general industrial machines, there are many means such as a belt, a pulley, a gear or a shaft coupling as a method for transmitting power by rotation.
In order to improve the reliability of the entire machine and prevent fatal accidents, there are many cases of incorporating a safety device to prevent overload in important parts.

In particular, in a propeller propulsion machine of a small ship and a compression circuit of a refrigerator compressor, it is necessary to always have a safety device for disconnecting power transmission on the prime mover side against overload on the driven side.

As such a safety device, there is a conventional device shown in FIG.
Shear pins such as those shown in are commonly used.
The shear pin 71 is inserted between the drive shaft 72 and a driven component (propeller in the figure) 73. When the driven component 73 is overloaded, the pin 71 is broken and the drive shaft 72 is idled.

However, in the structure using the shear pin described above, when repairing the driven side, it is necessary to replenish a new shear pin, which is a workability problem. In particular, in the propeller propulsion shaft of a small boat as shown in FIG. 20, it is necessary to replace the pins at sea, which poses a problem in that work is difficult and dangerous.

On the other hand, a torque limiter as shown in FIG. 21 has been proposed as a safety device that can be automatically restored and repeatedly used. This torque limiter is constructed by pressing a ball 82 held by a hub 81 on the driven side with a spring 83 and pressingly contacting a pocket 85 of a drive flange 84. When the hub 81 is overloaded, the ball 82 is pocketed. Climb from 85 and cut the overload. Further, when the drive flange 84 continues to rotate, the ball 82 enters another pocket 85 and automatically returns to restart the hub 81.

However, in the torque limiter described above, the automatic return operation is performed during the relative rotation of at least one rotation or less between the driving side and the driven side, so that even if the driven side stops due to an abnormality, the driving side is high. If spinning at speed,
There is a drawback that automatic recovery is repeated at extremely short time intervals. For example, when the drive flange 84 is rotating at 1800 rpm, engagement / disengagement of the ball 82 and the pocket 85 is repeated 30 times or more per second, and the torque transmission is restarted. This causes the wear of the contacting parts to significantly progress, and immediately restarts the driven side in an abnormal state, which causes a problem on the driven side.

Therefore, the present invention is to provide a torque limiter for restarting the starting operation at a predetermined long time interval without instantaneously restarting when the driven side stops due to an abnormal state. I am trying.

[0009]

In order to solve the above-mentioned problems, the first means of the present invention is to fit two races, one of which is a driving side and the other of which is a driven side, inside and outside, and both A cylindrical surface is formed on one of the facing surfaces of the bearing ring, and an engaging surface is formed on the other surface, and in the pocket of the cage incorporated between the two bearing rings,
An engaging member for engaging the cylindrical surface and the engaging surface is provided, and an engaging portion of the cylindrical surface or the engaging surface with the engaging member is elastically deformable. The deceleration means for decelerating and transmitting the rotation is connected.

Further, according to the second means of the present invention, the engaging surface is formed as a polygonal surface with respect to the cylindrical surface.

On the other hand, according to a third means of the present invention, the speed reducing means is provided so as to be associated with the driven-side bearing ring and the retainer so as to rotate together, and an annular ring which fits inside and outside with a gap therebetween. And an eccentricity imparting mechanism that causes one of the respective annular portions to be eccentric to bring the two annular portions into contact with each other.

[0012] According to a fourth aspect of the present invention, the speed reducing means is provided so as to be associated with the orbital ring on the driven side and the retainer so as to rotate together, and has an annular shape which fits inside and outside with a gap therebetween. And a rolling element that is press-fitted between the retainer and the drive-side bearing ring to bring the annular portions into contact with each other by deforming the annular portion associated with the retainer.

Further, according to a fifth aspect of the present invention, the engaging portion of the cylindrical surface or the engaging surface is formed of a plate-shaped elastic material, and the elastic material is allowed to deform on the back side of the elastic material. It provided a slime.

The sixth means of the present invention has a structure in which a projection toward the engaging surface or the cylindrical surface is provided on the surface of the elastic material.

Further, a seventh means of the present invention adopts a structure in which power transmission means such as a gear, a belt groove, and a spline are integrally formed on the driven side bearing ring in each of the above structures.

[0016]

In the above-mentioned first means, when the bearing rings rotate relative to each other, the engaging element engages the cylindrical surface and the engaging surface to establish the clutch, and the wheels rotate integrally.

In this state, when an overload is applied to the driven side race, the cylindrical surface or the engaging surface is elastically deformed, the engaging element passes through the engaging position, and the clutch is disengaged.

The passed engagement element is sent toward the next engagement position by the retainer, but the retainer is decelerated by the reduction gear with respect to the drive-side bearing ring and is rotationally driven. Moves at a low speed and moves to the next engagement position over a long time interval. When this engaging element reaches the position of the next cylindrical surface and engaging surface, the clutch is reengaged and the starting operation is performed.

In the second means, when the engaging surface is formed in a polygonal shape, a large number of engaging surfaces can be formed in the circumferential direction with respect to the cylindrical surface, so that a large number of engaging elements are associated with the cylindrical surface. It can be incorporated between the mating surfaces, and the torque that can be transmitted by the torque limiter can be increased.

Further, in the third and fourth means, when the retainer moves the engaging element passing between the cylindrical surface and the engaging surface toward the next engaging position, the retainer is It is driven in the rotational direction while contacting the fitted annular portion. In this case, when the fitted ring portions come into contact with each other and rotate, creep occurs, and both ring portions relatively move in the circumferential direction by a distance (πδ) obtained by multiplying the fitting gap δ by π in one rotation. It will be. Therefore, by setting the fitting clearance δ to a value that is sufficiently smaller than the nominal diameter dimension of both annular portions, it is possible to remarkably lengthen the time until the engagement element reaches the next engagement position. .

In the above means, each annular portion is
Either be formed integrally with the driven ring and the cage, or
It can be formed on a member mounted so as to rotate together with the driven ring or the cage.

On the other hand, in the fifth and sixth means, when the engagement element approaches the cylindrical surface and the engagement surface, the elastic material is deformed toward the recess of the back surface. In this case, the elastic member is largely deformed due to the engagement between the protrusion provided on the surface of the elastic member and the engaging member, and a large bending stress is generated inside the elastic member, so that a large elastic repulsive force is generated from the elastic member to the engaging member. Occurs. For this reason,
At the position where the maximum stress due to deformation occurs in the elastic material,
Maximum transmission torque can be generated.

Further, in the seventh means, since the power can be directly transmitted from the transmission means formed on the driven ring to the external equipment, the power transmission mechanism can be made compact. In addition, since the number of parts required for transmission can be reduced, the total cost when applying the torque limiter to a mechanical device or the like can be reduced.

[0024]

1 to 5 show a torque limiter of a first embodiment. As shown in FIGS. 1 and 2, an inner ring 1 and an outer ring 2
Is rotatably supported by bearings 3 and 4 arranged at both ends, and is coaxially held by the guides of the bearings 3 and 4.

The outer diameter surface of the center portion of the inner ring 1 is formed by a cylindrical surface 5, and the inner diameter surface of the outer ring 2 facing the cylindrical surface 5 is formed by a polygonal surface 6 of a substantially regular octagon. This polygon 6
A recess 7 having a predetermined length is formed in the central portion of each side in the length direction, and a rectangular ring-shaped leaf spring 8 having the same shape as the inner diameter of the polygonal surface 6 is fitted inside the outer ring 2.

The rectangular ring-shaped leaf spring 8 is incorporated into the polygonal surface 6 to a slight clearance or in an interference fit state. Both ends of each side are in close contact with both ends of each side of the polygonal surface 6. The central portion forms a flexible beam that supports both ends and is deformed toward the recess 7.

The inner diameter surface of each side of the leaf spring 8 serves as an engagement surface 9 which forms a wedge-shaped space with the cylindrical surface 5 of the inner ring 1, and each engagement surface 9 and the cylindrical surface 5 are formed. The dimension a of the minimum clearance 10 between them is set to be slightly smaller than the outer diameter dimension d of the roller 13, which will be described later.

The engaging surface 9 and the cylindrical surface 5 of the leaf spring 8 are also described.
An annular cage 11 is provided between the cage 1 and the cage 1.
A large number of pockets 12 are provided at equal intervals on the peripheral surface of No. 1 in correspondence with the engaging surface 9, and rollers 13 as engaging elements are incorporated in each of the pockets 12.

The roller 13 is formed so that the outer diameter dimension d is smaller than the gap other than the minimum clearance 10 between the engaging surface 9 and the cylindrical surface 5, and as shown in FIG.
The engaging surface 9 and the cylindrical surface 5 are engaged only in the vicinity of, and the engaging position constitutes a clutch having a strut angle θ.

Further, the roller 13 bends the leaf spring 8 so as to pass through a gap formed between the leaf spring 8 and the cylindrical surface 5. At the time of this deformation, the leaf spring 8 is supported at both ends. Acts as a flexure beam. Therefore, the torque that can be accurately transmitted can be set depending on the plate thickness of the leaf spring 8 and the amount of deflection thereof, and when a load equal to or greater than the torque is applied, the roller 13 is allowed to pass and the load is released.

As shown in FIG. 1, the outer diameter surface of the inner ring 1 is formed with an eccentric surface 15 which is eccentric with respect to the cylindrical surface 5 by an eccentric amount ε, and a bearing 16 is attached to the eccentric surface 15. The outer diameter surface of the bearing 16 is eccentric by ε with respect to the axis of the inner ring 1 due to the eccentricity of the eccentric surface 15.

The outer diameter surface of the bearing 16 has an O-ring 17
The cage 11 is brought into contact with the inner diameter surface of the cage 11 via a groove, and a radial force is applied to the cage 11 with respect to the inner ring 1 to slightly decenter the cage 11. In the above structure, the eccentric surface 15 and the bearing 16 constitute the eccentricity imparting mechanism 14 for the cage 11. The bearing 16 may be an eccentric bearing having an eccentric inner ring, and the eccentricity imparting mechanism may be configured by fitting the bearing 16 to a surface 15 formed concentrically with the cylindrical surface 5.

The elasticity of the O-ring 17 corrects the shape error of the outer diameter of the bearing 16 and the inner diameter of the retainer 11 to adjust the contact pressure of the bearing 16 to the retainer 11. Further, the bearing 3 incorporated between the outer ring 2 and the inner ring 1 receives the reaction force of the eccentric load by the bearing 16 and acts to smoothly generate the creep described later between the cage 11 and the outer ring 2.

On the other hand, the end portion of the outer ring 2 is L toward the inside.
A circular ring portion 19 is formed on the outer diameter surface of the bent portion 18 so as to enter the inside of the circular ring portion 20 at the tip of the cage 11. The outer diameter surface of the annular portion 19 is formed of a cylindrical surface coaxial with the outer ring 2, and as shown in FIGS. 3 and 4, a part of the outer diameter surface is a circle of the cage 11 which is eccentric in the radial direction. Ring part 2
It is in contact with the inner diameter surface of 0.

The clearance δ between the outer diameter dimension D _L of the annular portion 19 and the inner diameter dimension D _C of the annular portion 20 of the cage 11 is 1 with respect to the nominal diameter D of D _L and D _C. / 300 to 1/2
000 is set. In this case, the cage 11 is eccentric in the radial direction by the eccentric surface 15, but its amount is restricted by the outer diameter dimension D _L of the annular portion 19 and the inner diameter dimension D _C of the annular portion 20. It will be. That is, the eccentricity of the cage 11 is 1/2 of the clearance δ.
Therefore, the ring portion 20 of the cage 11 is the outer ring 2 only at one place.
It contacts the annular portion 19 of.

In the figure, 21 and 22, 23 are
Each of the bearings 4 and 16 is a washer that prevents the bearings from coming into contact with other parts, and 24 is a sealing plate that seals the lubricant.

The torque limiter of this embodiment has the structure as described above, and its operation will be described below. Now, the inner ring 1 is connected to the driving machine side, and the outer ring 2 is connected to the driven side, and as shown in FIGS. 1 and 2, the cylindrical surface 5 of the inner ring 1 and the engagement surface 9 of the rectangular ring-shaped leaf spring 8 are connected to the rollers. With 13 contacted,
When the inner ring 1 is rotated in the direction of the arrow, the roller 13 is engaged with the cylindrical surface 5 and the engagement surface 9 to establish a clutch having a strut angle θ, and the outer ring 2 rotates integrally with the inner ring 1.

From this state, when the torque applied to the outer ring 2 becomes large, as shown in FIG. 5, the engaging surface 9 of the leaf spring 8 constituting the clutch bends toward the recess 7 side, and the strut angle decreases as well. The torque that can be applied is reduced. Then, when the overload continues, the roller 13 has the minimum clearance 1
After passing through 0, it is released to the opposite side of the engaging surface 9 that was acting as a clutch, and loses the clutch function. As a result, the torque limiter of the embodiment exerts a torque releasing function for a torque equal to or higher than the set value, and functions as a safety device for preventing overload.

Since the released roller 13 is restricted in its circumferential movement by the retainer 11, and the retainer 11 is in contact with the annular portion 20 and the annular portions 19 of the outer ring 2,
Rotation of the roller 13 and the cage 11 is suppressed.

From the above state, when the drive side continues to rotate and the inner ring 1 and the outer ring 2 rotate relative to each other, the cage 11 is acted by the eccentricity imparting mechanism 14 so that the annular portion 19 of the outer ring 1 as shown in FIG. At the outer diameter of, it makes a rotational motion in contact and causes creep. That is, the annular portion 20 of the cage is the outer ring 1
During one rotation of the annular portion 19 of, the relative movement is made in the circumferential direction by an amount (πδ) obtained by multiplying the fitting clearance δ of that portion by π.

The rotation direction of this creep is the same as the rotation direction of the inner ring 1, and the rotation number of the creep, that is, the rotation number Nc of the cage 11 is Nc with respect to the rotation number N of the inner ring 1.
= (Δ / φD) × N In this case, since the value of the fitting clearance δ is set in the above range, the cage 11 is 1/300 to 1/2000 of the rotation speed of the inner ring 1.
It will rotate at the number of rotations. For example, when the rotation speed N of the inner ring 1 is 1800 rpm, the time T from when the clutch is released to when the clutch mechanism operates again is T = 1 / {(1800 / 60) x (1/300 to 1/2
000) × 8} = 1.25 to 8.33 seconds.

As described above, in the torque limiter of the embodiment,
When the torque exceeds the set torque, the clutch function is lost and the torque transmission is cut off. After a few seconds, the clutch is automatically re-engaged and this is repeated. Therefore, after the driven side has stopped in an abnormal state, it is possible to obtain a sufficient time margin, and the usage example in which the driven side abnormal state is recovered in a relatively short time, for example, a propeller propulsion machine for a small boat, It exhibits extremely effective functions as a safety device such as refrigeration compressor compression avoidance.

On the other hand, when the inner ring 1 rotates in the direction opposite to the arrow from the state shown in FIG. 1, the torque is not transmitted during the time when the clutch is idling, and thereafter, the clutch automatically operates to increase the torque. The transmission is performed, and the same operation as described above is performed thereafter.

The setting of the time from the interruption of the torque transmission to the reconnection is adjusted by adjusting the fitting gap δ between the outer diameter of the annular portion 19 of the outer ring and the inner diameter of the annular portion 20 of the cage. However, it is also possible to change the number of angles of the rectangular ring-shaped leaf spring 8.

6 to 8 show a second embodiment. In this example, a front lid 31 is press-fitted and fixed to one end of the outer ring 2, and a rear lid 32 is press-fitted to the other end thereof, and bearings 33 and 34 provided between the front lid 31 and the rear lid 32 and the inner ring 1 allow the outer ring to be formed. 2 is rotatably supported.

On the inner surface of the front lid 31, the holder 1 is attached.
1. A bent portion 31a that bends toward 1 is provided, and an annular portion 19 that fits inside an annular portion 20 provided at the tip of the cage 11 is formed on the outer diameter surface of the bent portion 31a. A fitting gap δ is provided between the annular portion 19 and the annular portion 20.

On the other hand, a groove 35 around the circumference is formed on the inner diameter surface of the annular portion 20, while a groove 36 around the circumference is formed on the outer diameter surface of the inner ring 1 so as to correspond to the groove 35. The three rolling elements 37 made of steel balls are press-fitted between the grooves 35 and 36. The rolling elements 37 are equally spaced in the circumferential direction by the ball cage 38 (120 degree intervals).
The cage 1 is arranged by means of rolling between the grooves 35 and 36.
1 is guided in the circumferential direction with respect to the inner ring 1.

The diameter D _W of the rolling element 37 is
The rolling element 37 is larger than the gap between the groove 35 provided in the cage 11 and the groove 36 provided in the inner ring 1, and each rolling element 37 is
1 and the inner ring 1 are set so as to be assembled in a press-fit state, and the press-fitting of the rolling element 37 causes the annular portion 20 of the retainer 11 to deform with each rolling element 37 as an apex, as shown in FIG. At the deformed portion 39, the annular portion 20 comes into contact with the annular portion 19 of the outer ring 2.

Regarding the other structure, the first structure described above is used.
Since it is the same as the embodiment of FIG.

In the second embodiment described above, when the inner ring 1 and the outer ring 2 rotate relative to each other, the roller 13 engages with the minimum clearance between the cylindrical surface and the engaging surface 9 to establish a clutch, and the two wheels are integrated. Rotate with. In this state, when the outer ring 2 is overloaded, the leaf spring 8 on the surface of the engaging surface 9 is deformed, and the roller 13
Passes through the minimum clearance and the clutch is disengaged.

The passed roller 13 is moved toward the next minimum clearance by the retainer 11, but the retainer 11
Is deformed by the press-fitting of the rolling element 37, a plurality of places of the annular portion 20 are in contact with the annular portion 19 of the outer ring, so that creep occurs, and the annular portions 19 and 20 are fitted with each other in one fitting gap. Relative movement in the circumferential direction by a distance multiplied by the pi.

In the above structure, the annular portion 20 of the cage 11 is
Since the contact between the ring portion 19 of the outer ring 2 and the outer ring 2 is made in three places, and the contact load on each of the ring portions 19 and 20 is dispersed and reduced, wear of the surface of each ring portion 19 and 20 is suppressed, and long contact is achieved. A lifetime is obtained.

FIG. 9 shows a third embodiment. In this example,
Six rolling elements 37 are incorporated between the cage 11 and the inner ring 1 at intervals of about 120 degrees, with two rolling elements 37 as one set. Each rolling element 37 is held at a predetermined position by a retainer 38. The six rolling elements 37 are arranged at positions where the revolving speed of each rolling element is the same.

On the other hand, in the fourth embodiment shown in FIG. 10, two rolling elements 37 are incorporated between the retainer and the inner ring, and both ring portions 1
It is designed so that the 9 and 20 are contacted at two places.
Further, in the example of FIG. 6, four rolling elements may be assembled at 180 degree intervals by setting two rolling elements between both annular portions.

The contact state between the cage and the annular portion of the outer ring is not limited to the contact at three or two points as in the above-mentioned example, and contact at four or more points by incorporating a required number of rolling elements. The state may be obtained.

By the way, in each of the above-mentioned embodiments, as shown in FIG. 2, the rectangular ring-shaped leaf spring 8 forming the engaging surface 9 is formed.
Each side of the plate spring 8 is formed in a flat plate shape so that the roller 13 slides smoothly, and a recess 7 for deforming the plate spring 8 is provided on the back surface of the central portion of the plate spring 8. In the structure in which the leaf spring 8 is supported at both ends in this way, the elastic strength of the central portion of the leaf spring 8 is small and the elastic strength of both end portions is large. For this reason, when the roller 13 approaches the minimum clearance of the engagement surface 9, the bending stress generated in the leaf spring 8 is as shown in FIG. 11, when the contact angle θ of the roller 13 is the central portion of the leaf spring 8. While it becomes maximum when it becomes zero, the magnitude of the torque that can be transmitted becomes larger as the angle θ becomes larger, and becomes zero when the angle θ at which the elastic repulsive force of the leaf spring 8 is small is zero.

That is, the magnitude of the torque that can be actually transmitted has a relationship between the reaction force due to the deformation of the leaf spring 8 and the contact angle θ of the roller 13, but in the above structure, when an attempt is made to increase the transmission torque. Since the maximum transmission torque cannot be generated at the position where the maximum stress of the leaf spring 8 occurs, there is a problem that the torque transmission efficiency becomes low.

On the other hand, the fifth embodiment shown in FIG. 12 shows an embodiment in which the shape of the leaf spring is improved in order to deal with the above problem. In this example, in the central portion of the leaf spring 8 forming the minimum clearance of the engaging surface 9,
A protrusion 41 facing the cylindrical surface 5 is provided.

The projection 41 is formed by providing two inclined portions 42 and 43 which are symmetrically inclined inward in the central portion of the leaf spring 8 where the contact angle θ becomes zero. Cylindrical surface 5 when the contact angle θ is zero with the surface of 43
The angle β formed by the tangent line of
The angle is set such that the roller 13 is sandwiched between the inclined portions 42 and 43 and the cylindrical surface 5 to act as a clutch (when the range is usually 5 to 15 degrees is desirable) when the bite 3 is engaged.

In the above structure, when the roller 13 approaches the minimum clearance of the engaging surface 9, the leaf spring 8 deforms toward the recess 7 on the back surface, but when the roller 13 enters the inside of the protrusion 41. Thus, the inclined portions 42 and 43 and the cylindrical surface 5 act on the roller 13 as a clutch. When the leaf spring 8 is largely deformed outward by the wedge action of the clutch, a large bending stress is generated inside the leaf spring 8.
A large repulsive force is generated from the leaf spring 8 to the roller 13.

For this reason, as shown in FIG. 13, the bending stress due to the deformation of the leaf spring 8 increases in proportion to the contact angle θ approaching zero, and the magnitude of the transmission torque also increases. Therefore, the maximum transmission torque can be generated at the position where the leaf spring 8 produces the maximum bending stress, and a large torque can be efficiently transmitted.

On the other hand, FIGS. 14 to 19 show a sixth embodiment. In this example, as shown in FIG. 14, a plurality of belt grooves 51 and 52 are formed on the outer diameter surface of the outer ring 2 so that the outer ring 2 itself can be used as a power transmission pulley. Further, as shown in FIGS. 14 and 15, a through hole 53 through which the drive shaft of the prime mover is inserted and a key groove 54 are formed on the inner diameter surface of the inner ring 1 on the drive side.
Is directly driven by a prime mover.

A cylindrical surface 5 is formed on the outer diameter surface of the central portion of the inner ring 1 in the same manner as in the above-mentioned embodiment, but the inner diameter surface 6 of the outer ring 2 facing the cylindrical surface 5 has a circular shape. 16 spring seats 55 are formed in the circumferential direction.
, 8 spring plates 8a, 8b, ... 8h are incorporated.

The spring plates 8a to 8h are arranged so as to have different pitches (intervals of positions at which they are engaged with the rollers 13) when assembled in the outer ring 2 as shown in FIG. The inner surface of each spring plate 8a to 8h forms an engagement surface 9 forming a wedge-shaped space with respect to the cylindrical surface 5 with respect to the cylindrical surface 5.

The spring plates 8a to 8h are assembled in a slightly interference fit between the spring seats 55 of the outer ring 2, and the spring plates 8a to 8h are mounted between the spring plates 8a to 8h and the inner diameter surface 6 of the outer ring 2. A recess 7 is provided to allow deformation of the plate. Further, a protrusion 41 directed toward the cylindrical surface 5 of the inner ring 1 is formed at the center of each spring plate 8a to 8h, and the engaging surface 9 near the protrusion 41 and the roller 13 contact each other to form each spring plate. 8a to 8h are adapted to be deformed.

An annular retainer 56 is provided between each spring plate and the cylindrical surface 5 of the inner ring 1, and the same pitch as that of each spring plate 8a-8h is provided on the peripheral surface of this retainer 56. 8 pockets 57 are formed, and the rollers 13 as the engaging elements are incorporated in the respective pockets 57. As shown in FIG. 19, the outer diameter dimension d of the roller 13 is such that the spring plates 8 a to 8 h are bent toward the recess 7 side and the spring plates 8 a to 8 h are bent.
It is set so that the roller 13 can pass through a space formed between a to 8h and the cylindrical surface 5.

The spring plates 8a-8h are shown in FIG.
Further, as shown in FIG. 18, a rear lid 58 that is press-fitted into the rear end of the outer ring 2 is inserted, and the rear lid 58 is provided with a flange 59 that elastically deforms the spring plate. This flange 59 has a projection 41 whose outer diameter surface is the inner surface of each spring plate 8a-8d.
Is formed in such a size that it abuts against the
Each spring plate is elastically deformed between the three points of 1 and the spring seats 55, 55 of the outer ring 2 so that a preload is applied. By incorporating the spring plates 8a to 8h in the preload state, the spring plates 8a to 8h are prevented from coming out of the outer ring 2 or being separated from each other due to vibration after assembling.

On the other hand, the tip of the retainer 56 is the bearing 33.
The annular member 60 coaxially with the inner and outer rings is connected to the protruding portion, and the annular portion 6 is attached to the inner diameter surface of the annular member 60.
1 is formed. The annular member 60 is tightly fitted to the retainer 12 by fitting the inner diameter surface of the annular member 60 and the uneven portion 67 provided at the end of the retainer 56, and by fitting the annular member 60 and the retainer 56. Is immovable in the axial direction, but is connected so as to be relatively rotatable in the rotational direction with a predetermined torque.

A front lid 62 having an L-shaped cross section is press-fitted at the tip of the outer ring 2, and an annular portion 63 which fits inside the annular member 60 is formed on the inner surface of the front lid 62. A fitting gap δ is provided between the annular portion 63 and the annular portion 61 of the annular member 60.

Further, a cylindrical roller bearing 64 is incorporated between the annular member 60 and the cylindrical surface 5 of the inner ring 1 as shown in FIGS. 16 and 17. This cylindrical roller bearing 64 is
An annular roller cage 65 and three cylindrical rollers 66 arranged at 120 degree intervals in the circumferential direction by the roller cage 65.
The cylindrical roller 66 rolls and the cage 5
6 is rotated and guided with respect to the inner ring 1.

The diameter of the cylindrical roller 66 is larger than the radial distance between the annular member 60 and the inner ring 1, so that each cylindrical roller 66 is assembled between the annular member 60 and the inner ring 1 in a press-fitted state. The press-fitting of the cylindrical roller causes the annular member 60 to be deformed with the cylindrical roller 66 as the apex as in FIG. 8, and the annular portion 61 and the annular portion 63 are brought into contact with each other at the deformed portion. It has become.

In the embodiment having the above structure, the drive shaft of the prime mover is fitted into the through hole 53 of the inner ring 1 and the outer ring 2 is inserted.
External devices on the driven side are directly connected to the belt grooves 51, 52 of the device via a transmission belt. Then, as shown in FIG. 15, when the inner ring 1 rotates in the direction of the arrow in a state where the roller 13 is in contact with the cylindrical surface 5 of the inner ring 1 and all the spring plates 8a to 8h, the roller 13 becomes the cylindrical surface 5. The clutch engages with the engagement surface 9 to establish a clutch. Therefore, the outer ring 2 rotates integrally with the inner ring 1, and the driving force is directly transmitted from the outer ring 2 to the external device.

From this state, when the torque applied to the outer ring 2 becomes large, as shown by the chain line in FIG. 19, the spring plates 8a to 8h forming the clutch are bent toward the recess 7 side, and when the overload continues, The roller 13 passes through the minimum clearance. In this case, the transmission torque when the eight spring plates 8a to 8h simultaneously bend and act is set to the limiter torque T.

When the prime mover continues to rotate while the above torque transmission is released and the inner ring 1 and the outer ring 2 rotate relative to each other, the annular member 60 comes into contact with the annular portion 61 and the annular portion 63.
Creep occurs while rotating around the outer diameter of the annular portion 63. Therefore, each roller 13 moves to the next engagement position at a low speed.

In this movement, when the spring plate 8d is first re-engaged with the next roller 13 as shown in FIG. 15, only the spring plate 8d engages at this time, and the engagement is unequal. Other spring plates 8a to 8c and 8e to 8 arranged at a pitch
Since h is not engaged, the transmission torque thereof is smaller than the limiter torque T, and the initially set torque is not transmitted to the driven outer ring 2.

Similarly, the other spring plates 8a-8c, 8e-
The rollers 13 are sequentially engaged with 8h, but in each case, the transmission torque is small because the eight spring plates do not engage at the same time.

Therefore, the engagement interval of the rollers 13 at the set torque is eight times that in the case where the respective sides of the leaf spring 8 have an equal pitch as shown in FIG. 2, and the time for the torque limiter to automatically return is set. The spacing will be extended eight times.

On the other hand, in the above structure, when the roller 13 moves to the next engagement position between the cylindrical surface 5 and the spring plates 8a to 8h and enters the engagement state, the cage 56 has a rotating structure as a rolling bearing. Since they are the same, they try to rotate at almost half the speed of rotation of the inner ring, but the ring member 60 that generates creep tries to rotate at a significantly lower speed than that, so the number of rotations between them is large. Difference occurs. In that case, when the torque generated by the difference between the rotations of the two exceeds the circumferential fixing force determined by the contact pressure of the interference fit portion between the cage 56 and the annular member 60, the cage 56 and the annular member. 60 rotates relative to each other to absorb the difference in rotation between the two. Therefore, the annular member 60 and the annular portion 63 that generate creep
A large slip does not occur between the contact portion of the roller 1 and the roller 13 and the inner ring 1, and the abrasion of the surface thereof is suppressed.

In the sixth embodiment, the spring plate 8a is used.
Although the case where the pitches of 8 to 8h are arranged so as to be different from each other has been described, they may be arranged at the same pitch as in the other embodiments.

Further, in each of the above-mentioned embodiments, the inner ring is on the driving side and the outer ring is on the driven side. Conversely, even if the inner ring is fixed and the outer ring is rotated on the driving side, the same operation as described above is performed. Is obtained.

Further, although the engaging surface 9 is formed by a plate-shaped spring and the clutch is opened by the deformation of the plate-shaped spring, the surface of the engaging surface 9 or the cylindrical surface 5 in the vicinity of the minimum clearance portion is formed. Only the elastic member such as rubber may be formed so that the roller 13 can pass by the elastic deformation.

[0082]

As described above, according to the present invention, a plurality of engaging positions where the engaging elements of the clutch are engaged by the cylindrical surface and the engaging surface are provided between the two bearing rings, and the holding elements hold the engaging elements. Since the container is decelerated and rotated with respect to the drive-side bearing ring, the engaging element that moves from one engagement position to the next engagement position can be rotated at a low speed. Therefore, it is possible to provide a torque limiter with a sufficient time margin for recovery from an abnormal state and machine stoppage, because the time from the disconnection of torque transmission by the clutch to the reconnection can be lengthened.

[Brief description of drawings]

FIG. 1 is a sectional view showing a torque limiter of a first embodiment.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a diagram for explaining the creep phenomenon of the embodiment.

FIG. 5 is an enlarged sectional view showing a clutch portion of the above.

FIG. 6 is a sectional view showing a second embodiment.

7 is a sectional view taken along line VII-VII of FIG.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 is a sectional view showing a third embodiment.

FIG. 10 is a sectional view showing a fourth embodiment.

FIG. 11 is a graph showing the relationship between the bending stress of the leaf spring and the transmission torque.

FIG. 12 is a sectional view showing a fifth embodiment.

FIG. 13 is a graph showing the relationship between the bending stress of the leaf spring and the transmission torque.

FIG. 14 is a sectional view showing a sixth embodiment.

FIG. 15 is a sectional view taken along line XV-XV in FIG.

16 is a sectional view taken along line XVI-XVI in FIG.

FIG. 17 is an enlarged cross-sectional view showing the creep occurrence portion of the above.

FIG. 18 is a sectional view taken along line XVIII-XVIII in FIG.

FIG. 19 is a sectional view showing the action of the above clutch.

FIG. 20 is a diagram showing a conventional example.

FIG. 21 is a diagram showing another conventional example.

[Explanation of symbols]

 1 Inner ring 2 Outer ring 5 Cylindrical surface 8 Square ring-shaped leaf spring 9 Engagement surface 10 Minimum clearance part 11 Cage 12 Pocket 13 Roller 14 Eccentricity imparting mechanism 15 Eccentric surface 16 Bearings 19 and 20 Ring part 37 Rolling body 38 Cager 41 Protrusions 51, 52 Belt groove 56 Retainer 60 Annular member 61 Annular portion 63 Annular portion 66 Cylindrical roller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. 4-203775 (32) Priority date Hei 4 (1992) July 30 (33) Priority claim country Japan (JP)

Claims (7)

[Claims] 1. Two bearing rings, one of which is a driving side and the other of which is a driven side, are fitted inside and outside, and a cylindrical surface is formed on one of the facing surfaces of the two bearing rings and an engagement surface is formed on the other. An engaging element for engaging the cylindrical surface and the engaging surface is provided in a pocket of the cage incorporated between the both races, and an engaging portion of the cylindrical surface or the engaging surface with the engaging element is elastic. A torque limiter with an automatic return function, which is formed so as to be deformable and in which a deceleration means for decelerating and transmitting the rotation of the drive-side bearing ring is connected to the cage. 2. The torque limiter with an automatic return function according to claim 1, wherein the engagement surface is a surface having a polygonal shape with respect to a cylindrical surface. 3. An annular portion provided in association with the orbital ring on the driven side and a retainer so as to rotate together with each other, and an annular portion fitted inside and outside with a gap therebetween, and the respective annular portions of the annular portion. The torque limiter with an automatic return function according to claim 1 or 2, further comprising: an eccentricity imparting mechanism that causes one of the annular portions to come in contact with each other by eccentricity. 4. The deceleration means is provided in association with the orbital ring on the driven side and the retainer so as to rotate together, and an annular portion fitted inside and outside with a gap therebetween, and on the retainer and the drive side. The torque with automatic return function according to claim 1 or 2, further comprising: a rolling element that is press-fitted between the annular ring portion and the bearing ring to deform the annular portion associated with the cage to bring the annular portion into contact with each other. limiter. 5. The cylindrical surface or the engaging portion of the engaging surface is formed of a plate-shaped elastic material, and the back side of the elastic material is provided with a dimple that allows deformation of the elastic material. A torque limiter with an automatic return function according to any one of 1. 6. The torque limiter with an automatic return function according to claim 5, wherein the elastic member has a surface provided with a protrusion toward the engagement surface or the cylindrical surface. 7. The torque limiter with an automatic return function according to claim 1, wherein a power transmission means such as a gear, a belt groove, and a spline is formed integrally with the driven-side bearing ring.