JP2012241796A - One-way clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-way clutch capable of suppressing the entire holder from being broken even if a roller jumps.SOLUTION: A plurality of rollers 3 arranged individually in wedge-like spaces S being formed in a plurality of numbers along the circumferential direction between an inner ring 1 and an outer ring 2, are housed respectively in pockets 4c formed in a plurality of numbers along the circumferential direction of a holder 4. The rollers are energized by an elastic member 5 along the direction the wedge-like space S becomes narrower. At each post 4b of the holder 4, a projection 4d for guiding the elastic member 5 when it is attached to the holder 4 is formed to protrude in each of the pockets 4c. The projection 4d includes a projection body part 4d1 which each of the rollers 3 hits when it jumps on the projection 4d side, and a fragile part 4d2 that is broken by the impact force at the time of collision.

Description

  The present invention relates to a one-way clutch.

  The conventional one-way clutch includes an inner ring and an outer ring, a plurality of cylindrical rollers individually disposed in a wedge-shaped space formed in the circumferential direction between the inner ring outer peripheral surface and the outer ring inner peripheral surface, A cage in which a plurality of pockets for individually accommodating the rollers are formed in the circumferential direction, and a plurality of elastic members that are individually disposed in each pocket and urge the rollers in a direction in which the wedge-shaped space is narrowed ( (For example, refer to Patent Document 1).

  The elastic member is attached to a cage, and at that time, the elastic member is guided by a projection protruding from the inner surface of the column portion of the cage. In the one-way clutch configured as described above, when the rollers are urged by the elastic member and pressed against and engaged with the inner and outer rings, the inner and outer rings rotate integrally, and when the engagement is released, the inner and outer rings rotate relative to each other. It is supposed to be.

JP 2002-39221 A

  When the one-way clutch is used for a long period of time, a lubricant such as grease deteriorates due to aging, so that the rollers are easily worn in a state where they are engaged with the inner and outer rings. As the wear progresses, a phenomenon may occur in which the roller slips between the inner and outer rings and jumps to the protrusion side at a high speed (hereinafter also referred to as a jumping phenomenon).

When such a phenomenon occurs, the roller collides against the tip of the protrusion against the urging force of the elastic member, but the impact force is received by the pillar portion of the cage that supports the protrusion. As a result, there is a problem that not only the pillar part which is a part of the cage is damaged by the impact force, but also the entire cage is finally damaged by the repeated collision.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a one-way clutch capable of suppressing the entire cage from being damaged even when a roller jump phenomenon occurs.

  To achieve the above object, the one-way clutch of the present invention is individually disposed in a wedge-shaped space formed in the circumferential direction between an inner ring and an outer ring, and an outer peripheral surface of the inner ring and an inner peripheral surface of the outer ring. A plurality of rollers, a pair of annular portions facing each other in the axial direction, and a plurality of column portions extending in the axial direction between the two annular portions and arranged at equal intervals in the circumferential direction to connect the two annular portions. A retainer in which each of the rollers is individually accommodated in a plurality of pockets formed between the adjacent pillars, and is individually accommodated in each pocket of the retainer and attached to the retainer. And a plurality of elastic members that urge the rollers in a direction in which the wedge-shaped space becomes narrower, and the rollers are pressed against and engaged with the inner and outer rings by the urging force of the elastic members. The wheel can be rotated as a unit and the mesh is released. A one-way clutch that allows relative rotation of the inner and outer rings, and a projection that guides the elastic member when the elastic member is attached to the retainer is formed in the pocket so as to project into the pocket. The protrusion has a protrusion main body portion that collides when the roller jumps in a direction to release the engagement, and a fragile portion that is damaged by an impact force at the time of the collision. To do.

  According to the present invention, since the protrusion protruding into the pocket from the pillar portion of the cage has a fragile portion that is damaged by an impact force when the roller jumps and collides with the protrusion main body portion, the roller jump phenomenon When this occurs, it is possible to prevent the impact force from being transmitted to the column portion via the protrusion by damaging only the protrusion. As a result, even if the collision is repeated, the entire cage can be prevented from being damaged.

  In the one-way clutch, it is preferable that the fragile portion is biased in a radial direction or an axial direction with respect to the protrusion main body portion. In this case, when the roller jumps and collides with the projection, the brittle portion breaks so that the projection main body portion is bent in the radial direction or the axial direction, so that the impact force at the time of the collision may be released in the radial direction or the radial direction. it can. Thereby, it can suppress effectively that the said impact force is transmitted to a pillar part.

  According to the one-way clutch of the present invention, when the roller jumping phenomenon occurs, only the protrusion is damaged, so that the impact force when the roller collides with the protrusion is prevented from being transmitted to the pillar portion of the cage. be able to. As a result, even if the collision is repeated, the entire cage can be prevented from being damaged.

It is sectional drawing which shows the power transmission device provided with the one-way clutch which concerns on one Embodiment of this invention. It is sectional drawing which shows the said one-way clutch. It is a top view which shows the holder | retainer of the said one-way clutch. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is a principal part expanded sectional view which shows other embodiment of a holder | retainer. It is a principal part enlarged plan view which shows other embodiment of a holder | retainer.

Hereinafter, embodiments of the one-way clutch of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing a power transmission device including a one-way clutch according to an embodiment of the present invention. This power transmission device is a pulley device with a built-in clutch for an alternator (hereinafter referred to as a pulley device) provided in a vehicle such as an automobile. The pulley device includes an annular sleeve 21 fixed to a rotating shaft (not shown) of an alternator, and an annular pulley 22 disposed coaxially with the sleeve 21 on the radially outer side of the sleeve 21. Yes. A belt groove 22a is formed on the outer peripheral surface of the pulley 22, and an endless drive belt 23 is hung on the belt groove 22a. The drive belt 23 is wound around the pulley 22 and a drive pulley (not shown) fixed to the crankshaft of the engine.

  A one-way clutch 10 and a pair of rolling bearings 20 are provided between the sleeve 21 and the pulley 22. A pair of rolling bearing 20 consists of a deep groove ball bearing, for example, and is arrange | positioned adjacent to the axial direction both sides of the one-way clutch 10. FIG. The rolling bearing 20 supports the sleeve 21 and the pulley 22 so as to be relatively rotatable, and also supports a radial load acting on the pulley 22.

  FIG. 2 is a cross-sectional view showing the one-way clutch 10. 1 and 2, the one-way clutch 10 includes a plurality of rollers disposed so as to be capable of rolling between an inner ring 1 and an outer ring 2, and an outer peripheral surface 1a of the inner ring 1 and an inner peripheral surface 2a of the outer ring 2. 3 is provided. The inner ring 1 is externally fitted and fixed to a sleeve 21, and rotates integrally with the sleeve 21. The outer ring 2 is arranged coaxially with the inner ring 1 and is fixed to the inner peripheral side of the pulley 22, and rotates integrally with the pulley 22. The roller 3 has a cylindrical shape, and eight rollers are arranged in the circumferential direction in this embodiment.

  The one-way clutch 10 further includes a cage 4 that holds the rollers 3 at equal intervals in the circumferential direction, and a plurality of elastic members 5 that elastically urge the rollers 3 in one direction. The cage 4 is made of a synthetic resin material mixed with a reinforcing material such as glass fiber, and extends in the axial direction between a pair of annular portions 4a facing each other in the axial direction, and the circumferential direction. It has a plurality of column parts 4b which are arranged at equal intervals and connect the two annular parts 4a. A plurality of pockets 4c are formed between both annular portions 4a and the adjacent column portion 4b, and each roller 3 is individually accommodated in each pocket 4c. The elastic member 5 is formed of a compression coil spring, and is individually accommodated in each pocket 4c of the cage 4 and attached to the column portion 4b.

  In FIG. 2, the inner peripheral surface 2 a of the outer ring 2 is a cylindrical surface, and the outer peripheral surface 1 a of the inner ring 1 is the same number (eight) cam surfaces as the rollers 3. The cylindrical surface of the outer ring 2 and the cam surface of the inner ring 1 A plurality of (eight) wedge-shaped spaces S are formed in the circumferential direction. The rollers 3 are individually arranged in each wedge-shaped space S, and the elastic member 5 urges the rollers 3 in the direction in which the wedge-shaped space S is narrowed. The outer peripheral surface of the roller 3 is a contact surface 3a that contacts the cylindrical surface of the outer ring 2 and the cam surface of the inner ring 1, and the contact surface 3a is formed straight in the width direction (axial direction). The one-way clutch 10 is in an environment in which grease is provided between the inner and outer rings 1 and 2 as a lubricant.

  In the one-way clutch 10 configured as described above, when the inner ring 1 and the outer ring 2 try to rotate relative to each other in one direction (clockwise direction in FIG. 2), the roller 3 is moved by the urging force of the elastic member 5. The wedge-shaped space S slightly moves in the direction of narrowing, the contact surface 3a of the roller 3 is in pressure contact with the outer peripheral surface 1a of the inner ring 1 and the inner peripheral surface 2a of the outer ring 2, and the roller 3 is between the inner and outer rings 1, 2. Will be engaged. By engaging the rollers 3 in this way, the inner and outer rings 1 and 2 can rotate integrally in the one direction.

  On the other hand, when the inner ring 1 and the outer ring 2 try to rotate relative to each other in the other direction (counterclockwise direction in FIG. 2), the roller 3 has a wide wedge-shaped space S against the urging force of the elastic member 5. By slightly moving in this direction, the engagement between the roller 3 and the inner and outer rings 1 and 2 is released. By releasing the engagement of the rollers 3 in this way, the relative rotation of the inner and outer rings 1 and 2 in the other direction is allowed.

  FIG. 3 is a plan view showing the cage 4 of the one-way clutch 10, and FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3 and 4, each column portion 4b of the retainer 4 has a protrusion 4d for guiding the elastic member 5 when the elastic member 5 is attached to the column portion 4b of the retainer 4. The axial center portion of the side surface 4b1 of the column portion 4b It is fixed to. The protrusion 4d is formed so as to protrude into the pocket 4c, and has a protrusion body part 4d1 formed on the front side and a weak part 4d2 formed on the base side. The protrusion main body 4d1 is formed so as to become gradually thinner toward the tip in the plan view of FIG. 3 and the side view of FIG. An elastic member 5 is loosely fitted to the protrusion main body 4d1 from the tip side.

  The tip surface 4d3 of the projection body 4d1 is a collision surface that collides when the roller 3 jumps as will be described later. The fragile portion 4d2 is formed to be fragile to such an extent that it is damaged by the impact force at the time of the collision. Specifically, as shown in FIG. 4, the fragile portion 4d2 is formed so that the thickness in the radial direction (vertical direction in FIG. 4) is thinner than the protrusion main body portion 4d1.

  Further, the fragile portion 4d2 is formed at a position biased radially inward (lower side in FIG. 4) with respect to the protrusion main body portion 4d1, and gradually increases in the radial direction toward the side surface 4b1 of the column portion 4b. It is formed to be thin. Thereby, when the roller 3 collides with the projection main body portion 4d1, the fragile portion 4d2 is damaged by the impact force such that the projection main body portion 4d1 is bent radially outward (upper side in FIG. 4).

  In the one-way clutch 10 configured as described above, if the one-way clutch 10 is used for a long period of time, the grease between the inner and outer rings 1 and 2 deteriorates due to secular change. Wear easily occurs when the outer peripheral surface 1a and the inner peripheral surface 2a of the outer ring 2 are engaged with each other. When this wear progresses, the roller 3 slips between the inner and outer rings 1 and 2 and, as indicated by an arrow B in FIG. The phenomenon of jumping and jumping may occur.

  In this case, the roller 3 collides against the front end surface 4d3 of the projection main body 4d1 against the urging force of the elastic member 5, and the impact force is transmitted from the projection main body 4d1 to the column portion 4b via the fragile portion 4d2. . However, in the one-way clutch 10 of the present embodiment, when the impact force is transmitted from the protrusion main body portion 4d1 to the fragile portion 4d2, the fragile portion 4d2 is damaged by the impact force. As a result, the protrusion main body 4d1 is bent radially outward as indicated by a two-dot chain line in FIG. 4, and therefore, the impact force can be prevented from being transmitted to the column portion 4b. As a result, even if the roller 3 jumps and the collision with the protrusion 4d is repeated, only the protrusion 4d in the pocket 4c where the jumping phenomenon occurs is damaged, and the annular portion 4a and the column portion 4b are included. It is possible to suppress the entire cage 4 from being damaged. If the entire cage 4 is damaged, the function of the one-way clutch 10 is suddenly lost. However, if the structure of the present invention is used, only the protrusion 4d that is a part of the cage 4 is damaged. Therefore, the function as the one-way clutch 10 can be maintained by the rollers 3 accommodated in the pockets 4c that remain without the protrusions 4d being damaged. That is, the function of the one-way clutch 10 is not suddenly lost, and the reliability of the one-way clutch 10 can be improved.

  Further, when the roller 3 jumps and collides with the projection main body portion 4d1, the fragile portion 4d2 is broken so that the projection main body portion 4d1 bends radially outward, so that the impact force at the time of the collision is released radially outward. Can do. Thereby, it can suppress effectively that the said impact force is transmitted to the pillar part 4b.

  FIG. 5 is an enlarged cross-sectional view of a main part showing another embodiment of the cage. The retainer 4 is formed at a position where the weakened portion 4d2 of the protrusion 4d is biased radially outward (upper side in FIG. 5) with respect to the protrusion main body portion 4d1. In the case of the present embodiment, when the roller 3 jumps in the direction indicated by the arrow B in FIG. 5 and collides with the projection main body 4d1, the projection main body 4d1 is radially inward (as indicated by the two-dot chain line in FIG. Since the fragile portion 4d2 is broken so as to be bent in the lower side of FIG. 5, the impact force at the time of the collision can be released radially inward. Thereby, it can suppress effectively that the said impact force is transmitted to the pillar part 4b.

  The present invention is not limited to the above-described embodiment, and can be implemented with appropriate modifications. For example, the shape of the protrusion 4d of the cage 4 may be as shown in FIG. 6 (a) or (b). The protrusion 4d in FIG. 6A is formed at a position where the fragile portion 4d2 is biased to one axial side (the upper side in FIG. 6A). In this case, due to the impact force when the roller 3 jumps, the fragile portion is bent so that the protrusion 4d bends to the other side in the axial direction (lower side in FIG. 6A) as shown by a two-dot chain line in FIG. 4d2 is damaged. The protrusion 4d in FIG. 6B is formed at a position where the fragile portion 4d2 is biased to the other side in the axial direction (the lower side in FIG. 6B). In this case, due to the impact force when the roller 3 jumps, the fragile portion 4d2 is bent so that the protrusion 4d bends to one side in the axial direction (the upper side in FIG. 6B) as indicated by the two-dot chain line in FIG. Will be damaged. 6A and 6B, the impact force can be released to one side in the axial direction or the other side in the axial direction, so that the impact force is transmitted to the column portion 4b. Can be suppressed.

Moreover, each shape of the protrusion main-body part 4d1 of the protrusion 4d and the weak part 4d2 is not restricted to the shape of the said embodiment, It can change suitably.
Furthermore, in the one-way clutch of this embodiment, the cam surface is formed on the outer peripheral surface 1 a of the inner ring 1, but the cam surface may be formed on the inner peripheral surface 2 a of the outer ring 2.

  1: inner ring, 1a: outer peripheral surface, 2: outer ring, 2a: inner peripheral surface, 3: roller, 4: retainer, 4a: ring portion, 4b: pillar portion, 4c: pocket, 4d: protrusion, 4d1: protrusion Body part, 4d2: weak part, 5: elastic member, 10: one-way clutch, S: wedge-shaped space

Claims (2)

An inner ring and an outer ring,
A plurality of rollers individually disposed in a wedge-shaped space formed in the circumferential direction between the inner ring outer circumferential surface and the outer ring inner circumferential surface;
A pair of annular portions facing each other in the axial direction, and a plurality of pillars extending in the axial direction between the annular portions and arranged at equal intervals in the circumferential direction to connect the annular portions, and adjacent to each other A cage in which the rollers are individually accommodated in a plurality of pockets formed between the pillars;
A plurality of elastic members that are individually accommodated in the pockets of the cage and attached to the cage, and bias the rollers in a direction in which the wedge-shaped space is narrowed,
A one-way clutch that allows the inner and outer rings to rotate integrally in a state in which the rollers are pressed against and engaged with the inner and outer rings by the urging force of the elastic member, and that allows relative rotation of the inner and outer rings in a state in which the engagement is released. There,
Each pillar portion of the retainer is formed with a protrusion protruding into the pocket for guiding when the elastic member is attached to the retainer.
The one-way clutch characterized in that the protrusion has a protrusion main body portion that collides when the roller jumps in a direction to release the engagement, and a weak portion that is damaged by an impact force at the time of the collision. .   The one-way clutch according to claim 1, wherein the fragile portion is biased in a radial direction or an axial direction with respect to the protrusion main body portion.

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