JP2008106913A - One-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch which surely holds a coil spring and surely maintains the state of power disengagement once the torque limiter is actuated to disengage the power in the case of application to one provided with a torque limiter. <P>SOLUTION: A projecting spring-guide 21 is formed in a retainer 14 in order to guide the coil spring 15. A protrusion 21a is formed in the spring guide 21 so as to reduce the clearance relative to a cam face 16 smaller than the wire diameter. A recess 21b is formed in the spring guide 21 so that the clearance between the cam face 16 and the coil spring 15 is made smaller than the diameter of the wire, and a recess 21b is formed in opposition to the protrusion 21a in the part of the spring guide 21 so that the coil spring 15 is easily thrust thereto. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a one-way clutch, and more particularly to a one-way clutch used in a pulley unit.

  For example, in a pulley unit installed in an auxiliary machine (for example, a compressor or alternator for an air conditioner) driven from a crankshaft of an automobile engine or the like, the tension fluctuation of the belt can be achieved by using a one-way clutch. It is designed to absorb the rotational fluctuations of the pulleys accompanying this.

  A pulley unit (1) for a compressor for an automobile air conditioner shown in FIG. 5 is connected to a crankshaft of an automobile engine via a belt (4) and transmits 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) and a coil spring (not shown) It has a cage (78) having a pocket for holding a plurality of rollers (77), and is arranged between the outer ring (71) outer diameter of the rolling bearing (7) and the cylindrical part (9a) inner diameter 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 (3) 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, Patent Document 1 has a recess for unlocking a roller in a region beyond the lock position on the cam surface, and is overloaded. The one-way clutch with a torque limiter that can be operated as a torque limiter in which the outer ring and the inner ring are in a free state and the power transmission is interrupted by being restrained in a state where the roller does not act as a biting member Has been proposed.
JP 2002-106608 A

  According to the one-way clutch with a torque limiter disclosed in Patent Document 1, when an overload is applied, the roller enters the unlocking recess, so that the locked state is eliminated, thereby transmitting power from the belt to the rotating shaft of the compressor. Since the belt is cut off, the problem of the belt burn-in or breakage is solved. However, the following problems exist to secure a more reliable power cut-off state. That is, when the torque limiter is activated, a gap is generated between the roller and the coil spring that biases the roller, and there is no need to hold the coil spring, so the coil spring becomes free and engages between the outer ring and the inner ring. In this case, it is possible that the power is transmitted again. Therefore, it is necessary to prevent the coil spring from being caught between the outer ring and the inner ring.

  The reason why the coil spring becomes free when there is nothing to hold the coil spring is because the spring is mounted by allowing the coil spring to fall freely, even in a one-way clutch without a torque limiter. It is a problem to prevent the coil spring from falling off while ensuring the ease of the above.

  The object of the present invention is to reliably hold the coil spring, and when applied to the one with a torque limiter, once the torque limiter is actuated and the power is cut off, the power cut-off state is ensured. It is to provide a one-way clutch that is maintained.

  A one-way clutch according to the present invention includes an outer ring, an inner ring, a plurality of rollers arranged between both race rings, a coil spring that urges each roller in a biting direction, and a cage that holds each roller. One of the inner ring and the inner ring is provided with a cam surface defining a lock position and a free position, and a protruding spring guide for guiding the coil spring is provided in the cage. In the clutch, the spring guide is provided with a projection for making the gap with the cam surface smaller than the wire diameter of the coil spring, and a recess for facilitating insertion of the coil spring in the portion of the spring guide opposite to the projection Is formed.

  The coil spring is fitted into the spring guide so that the tip portion protrudes, and the tip surface is applied to the roller. The protrusion is provided at a position where the first turn of the coil spring is caught so as not to hinder expansion and contraction of the coil spring. By forming a recess to facilitate the insertion of the coil spring in the spring guide part on the opposite side of the protrusion, the diameter of the spring guide in the part with the protrusion can be made smaller than the inner diameter of the coil spring. It becomes easy to mount the coil spring by free fall.

  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 cam surface may be formed on the inner ring or may be formed on the outer ring.

  The one-way clutch may be provided with a torque limiter or may not be provided with a torque limiter. In the one-way clutch with a torque limiter, for example, a lock-release concave portion into which a roller enters when overloaded is formed in a region beyond the lock position on the cam surface.

  In the case of a one-way clutch with a torque limiter, normally, the roller is in the cage pocket and moves in the circumferential direction between the locked position and the free position, thereby functioning as a one-way clutch. It is. In an abnormal state (overload), the roller is fitted into the unlocking recess of the cam surface by the excessive torque, thereby releasing the locked state. At this time, the coil spring is prevented from dropping from the spring guide by the protrusion, and the coil spring is not dropped and is not caught between the inner ring and the outer ring.

  According to the one-way clutch of the present invention, once assembled, the coil spring does not fall off, so that the subsequent work is facilitated, and when the torque limiter is provided, the coil spring is prevented from falling off. Since the coil spring is prevented from biting between the inner ring and the outer ring, 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.

  1 and 2 show a first embodiment of a one-way clutch according to the present invention.

  This one-way clutch (10) is used as the one-way clutch (10) shown in FIG. 5, 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 disposed in a wedge-shaped space (17) formed by the cam ring (16) defining the inner ring (12), the cam surface (16) and the inner peripheral surface of the outer ring (11), and the outer ring (11) When the inner ring (12) rotates relative to one direction (locking direction), the outer ring (11) engages with the inner ring (12), and when it rotates relative to the other direction (free direction) Roller (13) as a plurality of biting members to be released, coil spring (15) for biasing roller (13) in the biting direction (narrow side of wedge-shaped space (17)), roller (13) and coil It has a pocket (18) for accommodating the spring (15), and an annular cage (14) for positioning the roller (13) in the wedge-shaped space (17).

  The cam surface (16) is formed by forming the outer peripheral surface of the inner ring (12) to have a polygonal cross-sectional shape (an octagon in the figure), and a counterclockwise side portion of each surface (side in the cross-section) A space between the inner periphery of the outer ring (11) is used as a wedge-shaped space (17).

  The circumferential length of each pocket (18) of the cage (14) is smaller than the outer diameter of the roller (13) + the free length of the coil spring (15). Thereby, the roller (13) and the coil spring (15) are always in contact with each other regardless of the position of the roller (13). The axial dimension of the cage (14) pocket (18) is larger than the axial length of the roller (13), so that the roller (13) is pocketed between the locked and free positions. Guided by (18) and can move.

  The cage (14) is provided with a protruding spring guide (21) for guiding the coil spring (15), and the coil spring (15) is connected to the spring guide (21) as described later. It is fitted. The spring guide (21) is provided closer to the inner ring (12) side than the middle between the inner ring (12) and the outer ring (11). Contact with (11) is prevented. On the radially inner part of the spring guide (21), a protrusion (21a) is provided to make the gap with the cam surface (16) smaller than the wire diameter of the coil spring (15). A concave portion (21b) for facilitating the insertion of the coil spring (15) is formed at a position corresponding to the protrusion (21a) in the radially outer portion of).

  The inner ring (12) is formed with a lock release recess (19) in which the roller (13) enters when overloaded, in a region beyond the lock position on the cam surface (16).

  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. Thus, in a normal state (one-way clutch operation state), the roller (13) can move between the locked position and the free position, and when a large torque load is applied, the roller (13) becomes the inner ring (12). It is forced to move in a narrower direction of the wedge-shaped space (17) in a state of being bitten between the outer ring (11). When the roller (13) is fitted into the unlocking recess (19), the inner ring (12) and the outer ring (11) are in a free state.

  Therefore, according to the compressor pulley unit (see FIG. 5) provided with the one-way clutch (10), for example, when an abnormality occurs in the rotation of the rotating 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 unlocking 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. 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.

  When the coil spring (15) becomes free, the coil spring (15) may return to the locked state by being caught between the inner ring (12) and the outer ring (11), but the coil spring (15) The protrusion (21a) prevents the spring guide (21) from falling off, and the coil spring (15) does not get caught between the inner ring (12) and the outer ring (11). There is a limit to increasing the free length so that the coil spring (15) does not become free, but by preventing the coil spring (15) from falling off, the free length of the coil spring (15) is the same as before. Thus, the coil spring (15) can be restrained even when the torque limiter is operated.

  In order to assemble the one-way clutch (10), as shown in FIG. 3, a jig (22) corresponding to the inner ring (12) is used, and the cage (14) is assembled into the jig (22). After that, the coil spring (15) is fitted into the spring guide (21). In the jig (22), a recess (22a) is formed in a portion corresponding to the protrusion (21a) of the spring guide (21), so that the coil spring (15) can be It can be easily fitted into the guide (21).

  FIG. 4 shows a second embodiment of the one-way clutch according to the present invention.

  The one-way clutch includes a cylindrical outer ring (61), an inner ring (62) formed in a polygonal shape and having this portion as a cam surface (63), and an inner ring between the cam surface (63) and the outer ring (61). A roller (65) disposed in a wedge-shaped space (64) formed by the peripheral surface, an annular cage (66) for holding the roller (65), and a roller (65) having a narrow wedge-shaped space (64) And a coil spring (67) for urging to the side (lock side). The coil spring (67) is attached to a spring guide (68) provided in the cage (66) so as to protrude in the wedge-shaped space (64) direction.

  A protrusion (68a) is provided on the radially inner portion of the spring guide (68) to make the gap with the cam surface (63) smaller than the wire diameter of the coil spring (67). A concave portion (68b) for facilitating insertion of the coil spring (67) is formed at a position corresponding to the protrusion (68a) in the radially outer portion of). According to this one-way clutch, as shown in FIG. 3, the coil spring (67) can be easily inserted into the spring guide (68). The coil spring (67) can be prevented from falling off during work (such as assembling the cage assembly between the inner and outer rings).

  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. The one-way clutch described above has a cam surface formed on the inner ring, but the configuration in which the protrusion is provided on the spring guide similarly applies to the one-way clutch formed on the outer ring. Can be applied.

FIG. 1 is a cross-sectional view showing a first embodiment (with a torque limiter) of a one-way clutch according to the present invention. FIG. 2 is an enlarged view of a main part of FIG. FIG. 3 is a cross-sectional view showing a method of attaching a coil spring to the one-way clutch according to the present invention. FIG. 4 is a cross-sectional view showing a second embodiment (without a torque limiter) of the one-way clutch according to the present invention. FIG. 5 is a cross-sectional view showing a pulley unit for a compressor as an example in which the one-way clutch according to the present invention is used.

Explanation of symbols

(10) One-way clutch
(11) (61) Outer ring
(12) (62) Inner ring
(13) (65)
(14) (66) Cage
(15) (67) Coil spring
(16) (63) Cam surface
(19) Recess
(21) (68) Spring guide
(21a) (68a) Projection
(21b) (68b) Recess

Claims (3)

The outer ring, the inner ring, a plurality of rollers arranged between the two race rings, a coil spring that urges each roller in the biting direction, and a cage that holds each roller, and either one of the outer ring or the inner ring In the one-way clutch, a cam surface defining a lock position and a free position is formed on the raceway ring, and a protruding spring guide for guiding the coil spring is provided in the cage.
The spring guide is provided with a projection for making the gap with the cam surface smaller than the wire diameter of the coil spring, and a recess for facilitating insertion of the coil spring is formed in the portion of the spring guide opposite to the projection. One-way clutch characterized by that.   The one-way clutch according to claim 1, wherein a recess for releasing the lock is formed in a region beyond the lock position on the cam surface so that the roller enters when overloaded.   3. A method of assembling a one-way clutch according to claim 1 or 2, wherein the coil spring is fitted into the protruding spring guide after the retainer is assembled in the jig, and the concave portion is formed in the portion corresponding to the spring guide protrusion of the jig. And the coil spring can be easily fitted into the spring guide.

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