JP2008082454A - One-way clutch with torque limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch with a torque limiter capable of surely maintaining the power cut-off state after cutting off power by once operating a torque limiter. <P>SOLUTION: A cam surface 16 is formed on an inner ring 12. A recess 19 into which a roller 13 enters during overload is formed in a region exceeding a lock position on the cam surface 16. A pocket 18 in a retainer 14 includes a wide part 21 which movably guides the roller 13 moving between a lock position and free position and keeps the axial width longer than the length of the roller, and a narrow part 22 which disables the movement of the roller communicating with the wide part 21 and exceeding the lock position to enter into the recess 19 and keeps the axial width shorter than the length of the roller. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a one-way clutch, and more particularly to a one-way clutch with a torque limiter that is configured to release a locked state when an overload is applied in the locked state.

  For example, in a pulley unit equipped in an auxiliary machine (for example, a compressor for an air conditioner) driven from a crankshaft of an automobile engine or the like by using a belt, the use of a one-way clutch causes fluctuations in belt tension. It is designed to absorb the rotational fluctuation of the pulley.

  A pulley unit (1) for a compressor for an automobile air conditioner shown in FIG. 4 is connected to a crankshaft of an automobile engine via a belt (4) to transmit the engine power to a rotating shaft (3) of the compressor (2). ), A pulley (5) around which a belt (4) is wound, and a hollow shaft arranged on the inner diameter side of the pulley (5) and fixed to the rotating shaft (3) of the compressor (2) (6), an inner ring (71), an outer ring (72), a plurality of balls (73) arranged in two rows, and a retainer (74) for holding these balls (73), and a pulley inner diameter and a hollow shaft Double-row rolling bearing (7) placed between the outer diameter and bottomed cylindrical hub (supporting member for one-way clutch outer ring) fixed to the end of the rotating shaft (3) by a cap nut (8) (9), the inner ring (75) integrated with the outer ring (72) of the rolling bearing (7), the outer ring (76), a plurality of rollers (77) disposed between the two rings (75) (76), each roller ( 77) a biasing member (not shown) for biasing in the biting direction; It has a cage (78) with a pocket to hold a number of rollers (77) and is arranged between the outer diameter of the outer ring (71) of the rolling bearing (7) and the inner diameter of the cylindrical part (9a) of the hub (9). And a one-way clutch (10).

  The outer ring (76) of the one-way clutch (10) is integrated with the rotating shaft (3) via the hub (9), and the inner ring (75) of the one-way clutch (10) is integrated with the pulley (5). Has been. Accordingly, when the pulley (5) is rotationally driven by the belt (4) and power is transmitted from the pulley (5) to the rotating shaft (3) of the compressor (2) via the one-way clutch (10). The one-way clutch (10) is locked when the rotational speed of the pulley (5) is relatively faster than the rotational shaft (3) of the compressor (2), and the pulley (4), hub (9 ) And the rotating shaft (3) are integrated and rotated synchronously, and when the rotational speed of the pulley (5) becomes relatively slower than the rotating shaft (3) of the compressor (2), it enters a free state. Then, the transmission of the rotational power from the pulley (5) to the rotating shaft (3) of the compressor (2) is cut off, so that the rotating shaft (2) continues to rotate only with the rotary inertia force.

  A general one-way clutch does not have a function of interrupting transmission of power from the belt to the rotating shaft of the compressor when an overload is applied. There is a problem of burning or damage. In order to solve this problem, although not shown in the drawings, in Patent Document 1, a recess into which the roller enters is formed in a region beyond the lock position on the cam surface. A one-way clutch with a torque limiter is proposed in which the roller is constrained to not act as a biting member, whereby the outer ring and the inner ring are in a free state, and the operation as a torque limiter that interrupts power transmission is obtained. ing.

In this one-way clutch with a torque limiter, for example, when an abnormality occurs in the rotation of the rotary shaft due to a burn-in failure of the compressor, the load torque of the one-way clutch increases, and this value becomes a required specified value (for example, 60 Nm). When it reaches, the roller is moved to the narrower side of the lock position in the wedge-shaped space and enters the concave portion of the cam surface, so that the roller is not in contact with the pulley or idles, so that only the pulley rotates. Thus, the function of a torque limiter that cuts off power transmission from the pulley to the rotating shaft of the compressor is achieved.
JP 2002-106608 A

  According to the one-way clutch with a torque limiter disclosed in Patent Document 1, when the roller is overloaded, the roller enters the concave portion, so that the locked state is eliminated, thereby interrupting the transmission of power from the belt to the rotating shaft of the compressor. As a result, the problem of belt burn-in or breakage is solved, but the following problems exist in order to ensure a more reliable power shut-off state. That is, after the torque limiter is actuated, the roller may reversely move from the inside of the recess to the locked position due to engine vibration or rotation fluctuation, and the power can be transmitted again, thereby preventing the reverse movement. There is a need.

  An object of the present invention is to provide a one-way clutch with a torque limiter in which the power cut-off state is reliably maintained once the torque limiter is operated and the power is cut off.

  A one-way clutch with a torque limiter according to the present invention includes an outer ring, an inner ring, a plurality of rollers disposed between both wheels, a biasing member that biases each roller in a biting direction, and a cage having a pocket that holds each roller. A cam surface that defines the lock position and free position is formed on either the outer ring or the inner ring, and a recess is formed in the region beyond the lock position on the cam surface where the roller enters when overloaded. In the one-way clutch with a torque limiter, the pocket of the cage is configured so that the roller moving between the lock position and the free position is movably guided so that the axial width is larger than the roller length, and the wide portion And a narrow portion whose axial width is smaller than the roller length, making it impossible to move the roller that has entered the recess beyond the lock position. It is intended to.

  This one-way clutch includes, for example, a pulley around which a belt is wound, a rotating shaft arranged on the inner diameter side of the pulley, a rolling bearing arranged between the inner diameter of the pulley and the outer diameter of the rotating shaft, and a rolling bearing. It is suitably used as a one-way clutch in a pulley unit (power transmission device) having a one-way clutch disposed between an outer ring and a cylindrical hub inner diameter fixed to a rotating shaft. Such a pulley unit can be used in an auxiliary machine such as a compressor for an air conditioner of an automobile and other various devices.

  The outer ring, inner ring and rollers of the one-way clutch are made of metal, and the cage is made of synthetic resin. The biasing member is, for example, a coil spring, but is not limited thereto. The cam surface may be formed on the inner ring or may be formed on the outer ring.

  Normally, the roller is in the wide part of the pocket of the cage and moves between the locked position and the free position, thereby functioning as a one-way clutch. When an abnormality occurs (overload), the roller is fitted into the concave portion of the cam surface by the excessive torque and enters the narrow portion of the cage, thereby releasing the locked state. At the same time, the roller cannot be moved.

  According to the one-way clutch with a torque limiter of the present invention, at the time of overload, the roller fits into the recessed portion of the cam surface due to the excessive torque, and enters the narrow portion of the cage, so that the locked state is At the same time, the rollers cannot move, so that once the torque limiter is activated and the power is cut off, the power cut-off state is reliably maintained.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an embodiment of a one-way clutch with a torque limiter according to the present invention.

  This one-way clutch (10) is used as the one-way clutch (10) shown in FIG. 4, and is formed into a cylindrical outer ring (11) and a polygonal shape, and these portions are in a locked position and a free position. Is arranged in a wedge-shaped space (17) formed by an inner ring (12), which is a cam surface (16), and an inner peripheral surface of the cam surface (16) and an outer ring (11). The inner ring (12) and the inner ring (12) rotate relative to each other in one direction (locking direction) to engage between the outer ring (11) and the inner ring (12), and engage in relative rotation in the other direction (free direction). A roller (13) as a plurality of biting members for releasing the spring, and a coil spring (15) as a biasing member for biasing the roller (13) in the biting direction (narrow side of the wedge-shaped space (17)), And an annular cage (14) having a pocket (18) for accommodating the roller (13) and the coil spring (15) and positioning the roller (13) in the wedge-shaped space (17). .

  According to this one-way clutch (10), when the rotational speed of the outer ring (11) is relatively higher than that of the inner ring (12), the roller (13) moves to the narrow side of the wedge-shaped space (17) (counterclockwise in the figure). The outer ring (11) and the inner ring (12) are integrated and rotate synchronously. However, when the rotation speed of the outer ring (11) becomes relatively slower than the inner ring (12), the roller (13) is rolled to the wide side (clockwise in the figure) of the wedge-shaped space (17) and is free. Therefore, transmission of rotational power from the outer ring (11) to the inner ring (12) is interrupted, and the inner ring (12) continues to rotate only with the rotational inertia force.

  The one-way clutch (10) is formed with a recess (19) into which the roller (13) enters in a region beyond the lock position on the cam surface (16). Then, corresponding to the recess (19), as shown in FIG. 2, the pocket (18) of the retainer (14) can be moved with a roller (13) that moves between the locked position and the free position. The wide part (21) whose axial width is larger than the roller length is guided, and the movement of the roller (13) that continues to the wide part (21) and enters the recess (19) beyond the lock position is impossible. Thus, a narrow portion (22) having an axial width smaller than the roller length is formed. The cage (14) is made of synthetic resin, and the pocket (18) is elastically deformable.

  Therefore, according to the compressor pulley unit (see FIG. 4) provided with the one-way clutch (10), for example, when an abnormality occurs in the rotation of the rotary shaft (3) due to a seizure failure of the compressor (2), When the load torque of the one-way clutch (10) increases and this value reaches a required specified value (for example, 60 Nm), the roller (13) moves to the narrower side of the locking position in the wedge-shaped space (17) (in the figure). It is moved counterclockwise) and enters the recess (19) of the cam surface (16). As a result, the rollers (13) cannot be engaged between the two wheels (11) and (12), and the power transmission from the pulley (5) to the rotating shaft (3) of the compressor (2) is cut off. The function of the torque limiter is fulfilled.

  The width of the pocket (18) of the cage (14) (the width of the narrow portion (22)) at the position where the roller (13) fits into the recess (19) is shorter than the length of the roller (13). Therefore, as shown in FIGS. 3 (a) and 3 (b), the roller (13) fitted in the recess (19) is also rotated in the narrow portion (22) of the pocket (18). The movement is also impossible, and the roller (13) does not leave and return to the locked position. As a result, even when overloaded, the pulley (5) continues to rotate, causing no rotation loss of the crankshaft and preventing the belt (4) from slipping on the pulley (5). The service life of the compressor is improved, and the devices connected through the compressor (2) and the belt (4) are not adversely affected.

  In the case of the conventional one-way clutch shown in FIGS. 3 (c) and 3 (d) (the parts having the same shape as those of the one-way clutch (10) according to the present invention are denoted by the same reference numerals), the pocket (88) of the cage (84). Is the same at the position where the roller (13) fits into the recess (19) (the same width as the wide portion (21)), and the roller (13) in the recess (19) is rotatable and The inside of the pocket (88) can be moved in the circumferential direction. When the roller (13) is fitted into the recess (19), the roller (13) is rotating at a high speed, so that the roller (13) may come into contact with the bottom surface of the recess (19) and be violated. There is a possibility of moving in the reverse direction indicated by the arrow in (d) and returning to the biting position (lock position) indicated by the two-dot chain line in FIG. In this case, the torque limiter function is not continued.

  On the other hand, in the one-way clutch (10) according to the present invention, the torque limiter function once obtained does not reverse, and the seizure of the pulley accompanying the locked state is reliably prevented. To restore this state, the one-way clutch (10) may be disassembled to return the rollers (13) to their original positions, or the one-way clutch (10) itself may be replaced.

  In the above embodiment, the one-way clutch (10) has been described as a compressor pulley unit for an air conditioner of an automobile. However, the use of the one-way clutch is not limited to this. Further, the one-way clutch has a cam surface formed on the inner ring, but the pocket shape of the cage consisting of the wide part and the narrow part has one direction in which the cam surface is formed on the outer ring. The same applies to the clutch.

FIG. 1 is a cross-sectional view showing an embodiment of a one-way clutch according to the present invention. FIGS. 2A and 2B show the rollers held in the pockets of the cage. FIG. 2A is a cross-sectional view, and FIG. 2B is a diagram viewed from the outside in the radial direction. FIG. 3 schematically shows the operation and effect of the one-way clutch according to the present invention in comparison with the conventional one. (A) is a cross-sectional view, and (b) is a diagram viewed from the outside in the radial direction. It is. FIG. 4 is a cross-sectional view showing a pulley unit for a compressor which is an example in which the one-way clutch according to the present invention is used.

Explanation of symbols

(10) One-way clutch
(11) Outer ring
(12) Inner ring
(13) Roll
(14) Cage
(15) Coil spring (biasing member)
(16) Cam surface
(18) Pocket
(19) Recess
(21) Wide part
(22) Narrow part

Claims (1)

The outer ring, the inner ring, a plurality of rollers arranged between the two rings, a biasing member that biases each roller in the direction of biting, and a cage having a pocket that holds each roller, and either one of the outer ring or the inner ring In addition, in the one-way clutch with a torque limiter, a cam surface that defines a lock position and a free position is formed, and a recess is formed in the region beyond the lock position on the cam surface.
The cage pocket movably guides the roller that moves between the locked position and the free position, and has a wide portion whose axial width is larger than the roller length, and is connected to the wide portion and beyond the lock position in the recess. A one-way clutch with a torque limiter, characterized in that it has a narrow portion whose axial width is smaller than the length of the roller, making it impossible for the rollers to enter.

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