JP2012241759A - One-way clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-way clutch capable of smoothly a switching rotation state of inner and outer rings, and effectively suppressing breakage of a holder when jumping of a roller occurs.SOLUTION: In each pocket 4c of a holder 4 that holds rollers 3 with constant intervals along circumferential direction, a first elastic member 5 is stored between a post part 4b and the roller 3 which biases the rollers 3 in one direction to be in a locked state and tolerates the rollers 3 to move in the anti-biasing direction against the energizing force into a free state. Further, each pocket 4c houses a second elastic member 6 which biases the rollers 3 in the direction opposite to the jumping direction together with the first elastic member 5 only when the rollers 3 jump in the anti-biasing direction instead of in the free state, to suppress the post part from broken.

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 brought into a locked state where the rollers are pressed against and engaged with the inner and outer rings, the inner and outer rings rotate integrally, and the rollers resist the urging force of the elastic member. Thus, when it moves and enters a free state in which the mesh is released, the inner and outer rings rotate relative to each other.

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.

In order to solve this problem, it is conceivable to set a large spring constant of the elastic member and to avoid or alleviate the collision of the rollers by the biasing force. However, in this case, since the strong biasing force of the elastic member acts on the rollers even in a normal use state, the switching between the locked state in which the inner and outer rings are integrally rotated and the free state in which the inner and outer rings are relatively rotated is smoothly performed. It becomes impossible to do.
The present invention has been made in view of the above-described problems, and can smoothly switch the rotation state of the inner and outer rings, and is effective in breaking the cage when the roller jumping phenomenon occurs. It is an object of the present invention to provide a one-way clutch that can be suppressed to a low level.

  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. And a cage in which the rollers are individually accommodated in a plurality of pockets formed between adjacent column parts, and the rollers are in a locked state in which the rollers are pressed against and meshed with the inner and outer rings. A one-way clutch that allows the inner and outer rings to rotate integrally and allows the relative rotation of the inner and outer rings in a free state in which the meshing is released, and is individually provided between the column portion and the roller in each pocket of the cage. The wedge-shaped space is narrowed by the roller. A plurality of first elastic members that are biased in the direction to be in the locked state, and that allow the rollers to move in the counter-biasing direction against the biasing force to enter the free state; and the cage Only when the roller jumps in the counter-bias direction from the free state and biases the roller together with the first elastic member in the direction opposite to the jump direction. And a plurality of second elastic members that suppress damage to the pillar portion.

  According to the present invention, when the roller jumps in the counter-biasing direction against the biasing force of the first elastic member, the second elastic member attaches the roller together with the first elastic member in a direction opposite to the jumping direction. By urging, the impact force applied to the pillar portion of the cage can be reduced. Thereby, it is possible to effectively prevent the cage from being damaged by the roller jumping phenomenon. Further, since the biasing force of the second elastic member is applied only when the roller jumps in the counter-biasing direction rather than the free state, the roller is moved between the locked state and the free state. In this case, the urging force of the second elastic member is not applied to the rollers. Therefore, in a normal use state, the rotation state of the inner and outer rings can be smoothly switched.

  In the one-way clutch, it is preferable that the second elastic member has a spring constant larger than that of the first elastic member. In this case, since the second elastic member urges the roller in a direction opposite to the jumping direction with a stronger urging force than the first elastic member, it effectively suppresses the breakage of the pillar portion of the cage. Can do.

  In the one-way clutch, it is preferable that the first elastic member and the second elastic member are coil springs. In this case, with a simple configuration, the rotation state of the inner and outer rings can be smoothly switched in a normal use state, and the cage is effectively prevented from being damaged when the roller jumping phenomenon occurs. be able to.

  In the one-way clutch, it is preferable that the second elastic member is disposed inside the first elastic member. In this case, a space for arranging the first elastic member and the second elastic member in the pocket of the cage can be reduced.

  According to the one-way clutch of the present invention, it is possible to smoothly switch the rotation state of the inner and outer rings in a normal use state, and effectively suppress the breakage of the cage when the roller jump phenomenon occurs. can do.

It is sectional drawing of the power transmission device provided with the one way clutch which concerns on the 1st Embodiment of this invention. It is sectional drawing of the said one-way clutch. It is a principal part enlarged plan view of a holder | retainer. It is a principal part expanded sectional view of a holder | retainer. (A) is a side view of a 1st elastic member, (b) is a side view of a 2nd elastic member. It is a principal part expanded sectional view which shows the state in which the roller is urged | biased by the 2nd elastic member. It is a principal part expanded sectional view which shows the one-way clutch which concerns on the 2nd Embodiment of this invention.

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 of a power transmission device including a one-way clutch according to a first 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 of 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 and a retainer 4 that holds the rollers 3 at equal intervals in the circumferential direction. 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 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.

  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. A plurality (eight) of wedge-shaped spaces S are formed between the surfaces in the circumferential direction. Rollers 3 are individually arranged in each wedge-shaped space S. 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 in this way, when the inner ring 1 and the outer ring 2 are to rotate relative to each other in one direction (clockwise direction in FIG. 2), the roller 3 is in a direction in which the wedge-shaped space S is narrowed. The contact surface 3a of the roller 3 comes into 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 engaged with the inner and outer rings 1 and 2 in a locked state. 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 are to rotate relative to each other in the other direction (counterclockwise direction in FIG. 2), the roller 3 moves slightly in the direction in which the wedge-shaped space S is widened. 3 and the engagement between 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 an enlarged plan view of a main part of the cage 4 and FIG. 3 and 4, the one-way clutch 10 further includes a plurality of first elastic members 5 and a plurality of second elastic members 6 that elastically bias each roller 3 in one direction. The first elastic member 5 is formed of a compression coil spring, and is individually accommodated between the column portion 4b and the column 3 in each pocket 4c of the cage 4 and attached to the column portion 4b. At that time, the first elastic member 5 is guided by the protrusions 4d provided to protrude from the respective pillar portions 4b. The protrusion 4d also serves as a guide when the second elastic member 6 is attached to the cage 4.

  The first elastic member 5 attached in this way has one end in contact with the side surface 4b1 of the column portion 4b and the other end in contact with the contact surface 3a of the roller 3. As a result, the first elastic member 5 urges the roller 3 in the direction in which the wedge-shaped space S is narrowed to the locked state, and the roller 3 moves in the counter-biasing direction against the urging force. Thus, the free state is allowed.

  Similarly to the first elastic member 5, the second elastic member 6 is formed of a compression coil spring, and is individually accommodated between the column portion 4b and 3 in each pocket 4c of the cage 4, and attached to the column portion 4b. It has been. Further, as shown in FIGS. 5A and 5B, the second elastic member 6 has a winding diameter D2 smaller than the winding diameter D1 of the first elastic member 5, and a free length L2 of the first elastic member 6. The length is set shorter than the free length L1 of the member 5, and one end is in contact with the side surface 4b1 of the column portion 4b in a state of being disposed inside the first elastic member 5. Further, the second elastic member 6 has a spring constant larger than the spring constant of the first elastic member 5, the linear d <b> 2 being set larger than the wire diameter d <b> 1 of the first elastic member 5.

  As a result, as shown in FIG. 4, the second elastic member 6 is in contact with the rollers 3 in a normal use state in which the roller 3 moves between the locked state and the free state while being urged by the first elastic member 5. It is arranged in a non-contact position. Then, only when the roller 3 jumps in the counter-biasing direction from the free state against the biasing force of the first elastic member 5, the second elastic member 6 moves in the direction opposite to the jumping direction. 5 and the roller 3 are energized. At this time, as shown in FIG. 4, the free length L2 of the second elastic member 6 is set to be longer than the total length L3 in the protruding direction of the protrusion 4d, so that before the roller 3 collides with the protrusion 4d, the roller 3 can be energized.

  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. It becomes easy to wear in the locked state in which the outer peripheral surface 1a and the inner peripheral surface 2a of the outer ring 2 are engaged. As this wear progresses, the roller 3 slips between the inner and outer rings 1 and 2, causing a phenomenon that jumps at high speed in the direction indicated by the arrow B in FIG. 4.

  In this case, the roller 3 moves in the counter-biasing direction against the urging force of the first elastic member 5 and tries to collide with the front end surface 4d1 of the protrusion 4d on the column part 4b side of the cage 4. However, in the one-way clutch 10 of the present embodiment, as shown in FIG. 6, the roller 3 abuts against the second elastic member 6 before colliding with the protrusion 4 d, so that the roller 3 is moved by the second elastic member 6. It is biased in the direction opposite to the jumping direction. Thereby, since it can avoid or relieve | moderate that the roller 3 collides with protrusion 4d, the impact force added to the pillar part 4b of the holder | retainer 4 can be reduced, and it suppresses that the pillar part 4b is damaged. be able to. Therefore, it is possible to effectively suppress the entire cage 4 from being damaged by the jumping phenomenon of the rollers 3.

  Further, as shown in FIG. 4, since the biasing force of the second elastic member 6 is applied only when the roller 3 jumps in the counter-biasing direction rather than the free state, the roller 3 is in the locked state and the free state. In a normal use state of moving between the two, the urging force of the second elastic member 6 is not applied to the rollers 3. Therefore, in the normal use state, the rotation state of the inner and outer rings 1 and 2 can be switched smoothly.

  Further, since both the first elastic member 5 and the second elastic member 6 are composed of compression coil springs, the rotation state of the inner and outer rings 1 and 2 can be smoothly switched in a normal use state with a simple configuration. At the same time, the cage 4 can be effectively prevented from being damaged when the roller 3 jumps.

Further, since the second elastic member 6 has a spring constant larger than the spring constant of the first elastic member 5, the roller 3 is pushed in a direction opposite to its jumping direction with a stronger biasing force than the first elastic member 5. Can be energized. Thereby, it can suppress effectively that the pillar part 4b of the holder | retainer 4 is damaged.
Further, since the second elastic member 6 is disposed inside the first elastic member 5, a space for disposing the first elastic member 5 and the second elastic member 6 in the pocket 4 c of the cage 4 is reduced. be able to.

  FIG. 7 is an enlarged cross-sectional view of a main part showing a one-way clutch according to a second embodiment of the present invention. In the one-way clutch of the present embodiment, the protrusion 4d that protrudes from the column portion 4b of the cage 4 also serves as the second elastic member. Specifically, the protrusion 4d is a protrusion main body part 4d2 protruding from the side surface 4b1 of the pillar part 4b, and a second elastic member fixed to the protrusion main body part 4d2 so as to cover the protrusion main body part 4d2. It is comprised by the elastic part 4d3.

  The protrusion main body 4d2 is made of the same material as the pillar 4b, which is another component of the cage 4, and is made of a synthetic resin material mixed with a reinforcing material such as glass fiber. The elastic portion 4d3 is made of synthetic rubber and has a spring constant larger than that of the first elastic member 5. The outer shape of the elastic portion 4d3 is formed to be the same as the outer shape of the protrusion 4d in the first embodiment so that it can be guided when the first elastic member 5 is attached.

  In the case of this embodiment, when the roller 3 jumps at a high speed in the direction indicated by the arrow B in FIG. 7, the roller 3 moves in the counter-biasing direction against the biasing force of the first elastic member 5, and the elastic portion 4d3. It collides with the tip surface 4d1. At that time, the elastic part 4d3 is elastically deformed, whereby the impact force at the time of the collision can be reduced. Thereby, it can suppress effectively that the holder | retainer 4 is damaged by the jumping phenomenon of the roller 3. FIG.

  The present invention is not limited to the above-described embodiment, and can be implemented with appropriate modifications. For example, in the first embodiment, the second elastic member 6 is disposed inside the first elastic member 5, but the winding diameter D <b> 2 of the second elastic member 6 is larger than the winding diameter D <b> 1 of the first elastic member 5. The second elastic member 6 may be disposed outside the first elastic member 5 by increasing the size.

Further, the first elastic member 5 may be other elastic members such as a leaf spring and a synthetic rubber in addition to the compression coil spring. Further, the second elastic member 6 may be another elastic member such as a leaf spring in addition to the above embodiment.
In the above-described one-way clutch 10, 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, 5: first elastic member, 6: second elastic member, 10: one-way clutch, S: wedge-shaped space

Claims (4)

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 pillar portions,
A one-way clutch that allows the inner and outer rings to rotate integrally in a locked state in which the rollers are pressed against and engaged with the inner and outer rings, and that allows relative rotation of the inner and outer rings in a free state in which the engagement is released;
In each pocket of the cage, it is individually accommodated between the column portion and the roller, and the roller is urged in the direction in which the wedge-shaped space is narrowed to be in the locked state and resists the urging force. A plurality of first elastic members that allow the rollers to move in the counter-biasing direction to enter the free state;
Only when the rollers are individually accommodated in the pockets of the cage and the rollers jump in the counter-biasing direction from the free state, the rollers are biased together with the first elastic member in the direction opposite to the jumping direction. And a plurality of second elastic members that suppress damage to the pillar portion.   The one-way clutch according to claim 1, wherein the second elastic member has a spring constant larger than that of the first elastic member.   The one-way clutch according to claim 1 or 2, wherein the first elastic member and the second elastic member are coil springs.   The one-way clutch according to claim 3, wherein the second elastic member is disposed inside the first elastic member.

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