JP2008185108A - Pulley unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically block transmission of rotary torque when a relative rotation speed between a drive ring and a driven ring exceeds a predetermined level, in a one-way clutch in a pulley unit. <P>SOLUTION: In an annular space part formed between an outer ring 8 (drive ring) and an inner ring 9 (driven ring) concentrically arranged, an annular cage 12 for housing respective rollers 13 therein is arranged rotatably only in a counterclockwise direction with respect to the inner ring 9; a contact surface 23a at a free end of a weight member 17 mounted rotatably in the circumferential direction of the inner ring is brought into contact with an inner peripheral surface 16a of a second pocket 16 with tensile force of a tension spring 24; and, when the rotating speed of the inner ring 9 exceeds a predetermined level, the weight member 17 is rotated in a direction reverse to a rotating direction by its rotating centrifugal force to forcibly push back the cage 12, whereby the roller 13 arranged in a wedge upper space part 19 in a lock state is moved to a position in an unlock state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pulley unit using a one-way clutch mechanism.

  Rotational torque from the engine of the vehicle (automobile) is belt-transmitted from the crank pulley to the driving wheel on the outer ring side of the pulley unit mounted on the auxiliary machine rotation shaft, via a one-way clutch mechanism incorporated in the pulley unit. , And transmitted to the auxiliary machine rotation shaft (driven wheel) on the inner ring side. As this auxiliary machine, there are an air conditioner compressor, a water pump, an alternator, a cooling fan, and the like. And as this pulley unit, the technique disclosed by patent document 1, 2 exists.

In recent years, alternator pulleys (primary wheels) have become smaller in diameter in response to engine idling. For this reason, when the engine rotates at high speed, the alternator (driven wheel) also rotates at a high speed corresponding to the pulley ratio. However, in the case of an alternator, even if the rotational speed exceeds a certain level, the amount of power generation does not increase. For this reason, it is inefficient even if the rotation speed of the alternator is increased unnecessarily. Moreover, because the alternator has to be strengthened for parts such as a bearing that supports the rotating shaft so that the alternator can cope with high-speed rotation, useless costs are generated.
JP 2001-82586 A JP 2002-106686 A

  In view of the above-described problems, the present invention automatically interrupts transmission of rotational torque when the relative rotational speed of the driving wheel and the driven wheel exceeds a predetermined level in the one-way clutch in the pulley unit. The challenge is to do so.

Means for Solving the Problems and Effects of the Invention

The present invention for achieving the above-mentioned problems
In a pulley unit comprising a driving pulley, a driven rotation shaft, and a one-way clutch mechanism interposed between the driving pulley and the driven rotation shaft,
The one-way clutch mechanism is
A driving wheel rotated integrally with the driving pulley,
A cam surface having a rotational radius that changes along the circumferential direction so as to form a wedge-shaped space between the driven wheel and the driven wheel. The cam surface is fixed to the driven rotary shaft and rotates integrally with the driven rotary shaft. A driven wheel,
Switching between a locked state disposed in the wedge-shaped space portion and being bitten in the wedge-shaped space portion and an unlocked state in which the biting is released, and the rotational speed of the driving wheel is the rotational speed of the follower. A wedge member that is locked into the wedge-shaped space when it falls below,
It has a pocket-shaped space portion that is disposed in an annular space formed between the driving wheel and the driven wheel, is rotatable relative to the driving wheel and the driven wheel, and holds the wedge member. An annular cage;
In a state where the wedge member is in the locked state and the driven wheel is rotating following the driving wheel, the level is changed from a normal rotation state in which the rotational speed of the driving wheel is less than a predetermined level. As the state shifts to a high-speed rotation state that exceeds, the rotational centrifugal force causes the cage to rotate in a direction opposite to the rotation direction, thereby forcing the wedge member from the locked position to the unlocked position. A cage moving mechanism to be moved;
It is characterized by having.

  In the present invention, the cage can rotate relative to the driven wheel. When the rotational speed of the driving wheel shifts to a high-speed rotation state exceeding a predetermined level, the cage rotates the cage in the opposite direction by the rotational centrifugal force, and the wedge member And a cage moving mechanism for forcibly moving the device from the locked position to the unlocked position. That is, when the driving wheel rotates at a high speed exceeding a predetermined level, the rotational centrifugal force acts on the cage moving mechanism, so that the rotation speed of the driven wheel is automatically suppressed, and the driven wheel is determined in advance. It will not be rotated at a rotational speed exceeding the specified level. For this reason, it is not necessary to unnecessarily increase the strength of the driven wheel, and the cost of the pulley unit can be reduced.

Specifically, the cage moving mechanism is
A base end portion is attached to the driven wheel so as to be rotatable along the rotation direction of the driving wheel, and a free end portion enters the pocket-shaped space portion of the cage and is disposed close to the inner peripheral surface thereof. A weight member,
A rotation restricting means for preventing the weight member from rotating in a direction opposite to the rotation direction of the driving wheel in a normal rotation state of the driving wheel;
Can be equipped with.

  The cage moving mechanism can be realized with a simple configuration by the weight member and the rotation restricting means.

  The rotation restricting means may be a tension spring attached between the free end portion of the weight member and the driven wheel.

  Since the rotation restricting means is a tension spring, its configuration is extremely simple and inexpensive.

  And the said weight member can be made to be attached alternately between the said wedge members in the circumferential direction.

  Since the weight member and the wedge member are alternately attached in the circumferential direction, the balance between the function of the weight member and the function of the wedge member is good, and the generation of abnormal noise and flapping is suppressed.

  Further, the weight member may be attached in parallel with the wedge member in the axial direction.

  In this case, the wedge member can be attached without reducing the number of weight members. For this reason, the function of the one-way clutch mechanism is not limited at all.

  Examples of the present invention will be described. 1 is a cross-sectional view of a pulley unit 100 to which a one-way clutch 5 is attached, FIG. 2 is a cross-sectional view taken along line XX of FIG. 1, FIG. 3 is a perspective view of an inner ring 9 and a cage 12, and FIG. It is an enlarged view of the principal part.

  As shown in FIG. 1, the pulley unit 100 of the present embodiment includes an auxiliary machine rotation shaft 1, a pulley 2 that is concentrically arranged on the outer peripheral portion of the auxiliary machine rotation shaft 1, and an outer peripheral surface of the auxiliary machine rotation shaft 1. And two rolling bearings 3 and 4 disposed in an annular space formed between the inner periphery of the pulley 2 and a one-way clutch 5 interposed between the rolling bearings 3 and 4. I have. The auxiliary machine rotating shaft 1 is connected to an input shaft of an auxiliary machine (for example, an alternator) of an automobile engine. A plurality of belt grooves 2a are provided on the outer peripheral surface of the pulley 2 (alternator pulley), and a belt 6 from a crankshaft of an automobile engine is hung on each belt groove 2a. The pulley 2 is driven and rotated by the power of the engine. In FIG. 1, 7 is a seal.

  First, the one-way clutch mechanism (one-way clutch 5 in this embodiment) will be described. As shown in FIGS. 1 and 2, the one-way clutch 5 includes an outer ring 8 (driving wheel) that rotates integrally with the pulley 2, and an inner ring 9 (driven wheel) that is arranged concentrically with the outer ring 8. The cage 12 is disposed in an annular space formed between the outer ring 8 and the inner ring 9. The outer peripheral surface of the inner ring 9 has a regular octagonal shape, and each flat surface has a wedge-shaped space portion 19 (for locking each wedge member (roller 13) held by the cage 12 (locked state)). A cam surface 14 is formed to form (described later).

  As shown in FIGS. 3 and 4, the cage 12 has a substantially cylindrical shape, and its maximum inner diameter is slightly larger than the maximum outer diameter of the inner ring 9. The retainer 12 is non-rotatable in the clockwise direction with respect to the inner ring 9 by the protrusion 12a provided on the inner diameter side, but is rotatable in the counterclockwise direction. Yes. The cage 12 is provided with a plurality of pockets 15 and 16 at a predetermined interval in the circumferential direction. In the case of the one-way clutch 5 of the present embodiment, four first pockets 15 for arranging the rollers 13 are provided, and four second pockets for arranging each weight member 17 (described later). A pocket 16 is provided. The first and second pockets 15 and 16 are alternately provided in the circumferential direction.

  A compression spring 18 is attached to the inner peripheral surface 15a on one side of the first pocket 15 in the cage 12 to urge the roller 13 and place the roller 13 in the vicinity of the biting position. Further, the inner peripheral surface 15 b on the other side of the first pocket 15 has a hollow shape (V shape) corresponding to the outer diameter of the roller 13. Here, each cam surface 14 of the inner ring 9 is a flat surface, whereas the inner peripheral surface of the outer ring 8 is curved in a circular shape. For this reason, of the annular space portion, the space portion surrounded by the cam surface 14 of the inner ring 9, the inner peripheral surfaces 15 a and 15 b of the first pocket 15 and the inner peripheral surface of the outer ring 8 is the both ends of the cam surface 14. The height of the portion (the side close to the inner peripheral surfaces 15a and 15b) is a wedge-shaped space portion 19 that is lower than the height of the central portion. The outer diameter of each roller 13 is smaller than the maximum height of the wedge-shaped space portion 19 (the height of the central portion of the cam surface 14), and the height of the wedge-shaped portion (both ends of the cam surface 14). A little larger than). Each roller 13 is disposed in the vicinity of the biting position of the wedge-shaped space 19 by the urging force of the compression spring 18. At this time, a minute gap exists between the outer peripheral surface of each roller 13 and the inner peripheral surface of the outer ring 8 or the cam surface 14 of the inner ring 9. Thereby, the rotational torque of the outer ring 8 is not transmitted to the inner ring 9 (unlocked state).

  Next, the cage moving mechanism will be described. As shown in FIGS. 3 and 4, a weight member 17 is attached to the second pocket 16 of the cage 12. That is, a recess 21 is provided in the cam surface 14 corresponding to the second pocket 16 of the cage 12 in the inner ring 9. The base end portion 17 a of the weight member 17 is accommodated in the recess 21. A fulcrum shaft 22 attached to the recess 21 along the axial direction of the inner ring 9 is inserted into the base end portion 17 a of the weight member 17, and the weight member 17 is circumferential with respect to the axis of the fulcrum shaft 22. It can be rotated along. The free end portion 23 of the weight member 17 bulges toward the inner peripheral surface 16a side of the second pocket 16, and the end surface portion is disposed opposite to the inner peripheral surface 16a of the second pocket 16. A contact surface 23a is formed. Further, the free end portion 23 of the weight member 17 is connected to the bottom surface portion of the concave portion 21 of the inner ring 9 via a tension spring 24. For this reason, the free end 23 of the weight member 17 is always pulled by the tension spring 24.

  Since the contact surface 23a of the weight member 17 is in contact with the inner peripheral surface 16a of the second pocket 16, the counterclockwise rotation of the cage 12 is restricted. Further, the surface (back surface 23 b) opposite to the contact surface 23 a of the cage 12 and the inner peripheral surface 16 b of the second pocket 16 are disposed close to each other.

  The operation of the one-way clutch 5 of this embodiment will be described. As shown in FIG. 4, when the outer ring 8 is in a stationary state (non-rotating state), the tension force of the tension spring 24 acts on the free end portion 23 of the weight member 17, and the contact surface 23a is held. Abutted against the second pocket 16 of the vessel 12. For this reason, the retainer 12 does not rotate counterclockwise. Further, in this state, each roller 13 is urged by the compression spring 18 and is disposed in the vicinity of the biting position of the wedge-shaped space portion 19 formed in the portion of the first pocket 15 of the corresponding retainer 12. Yes. (Unlocked).

  When the outer ring 8 is driven and rotated in the direction of the arrow 25 (the urging direction of the compression spring 18), the roller 13 is moved in the urging direction of the compression spring 18 while rolling (spinning). For this reason, the roller 13 enters the end portion (biting position) of the wedge-shaped space 19 and is bitten by the wedge-shaped space 19 (locked state). This state is indicated by a two-dot difference line in FIG. As a result, the rotational torque of the outer ring 8 reaches the inner ring 9 (meaning that “the clutch is connected”), and the outer ring 8 and the inner ring 9 are integrally rotated in the direction of the arrow 25. Since the contact surface 23a of the free end portion of the weight member 17 is in contact with the inner peripheral surface 16a of the second pocket 16 of the cage 12 by the tensile force of the tension spring 24, the rotating weight member 17 vibrates. The generation of abnormal noise is suppressed.

  As shown in FIG. 5, when the rotational speeds of the outer ring 8 and the inner ring 9 exceed a predetermined level and the rotational centrifugal force of the inner ring 9 becomes larger than the tensile force of the tension spring 24, the weight member 17 gradually , About the axis of the fulcrum shaft 22 is rotated in the direction of the arrow 20 (the direction opposite to the arrow 25). The back surface 23b of the weight member 17 comes into contact with the inner peripheral surface 16b of the second pocket, and the cage 12 is forcibly pushed back in the direction of the arrow 26 (the direction opposite to the arrow 25). As a result, the cage 12 is rotated in the direction of the arrow 26 to move the roller 13 disposed at the biting position in the first pocket 15. The roller 13 is released from the pressure contact state (locked state) between the inner peripheral surface of the outer ring 8 and the cam surface 14 of the inner ring 9, and is brought into a floating state (unlocked state) by centrifugal force. As a result, the rotational torque of the outer ring 8 does not reach the inner ring 9 (meaning that the clutch is disengaged), and the inner ring 9 rotates by inertia, so that the rotational speed of the inner ring 9 does not increase any more. In other words, when the rotational speed of the inner ring 9 exceeds a predetermined level, the rotational speed is automatically suppressed.

  When the rotational speed of the inner ring 9 falls below a predetermined level, the tension force of the tension spring 24 becomes larger than the centrifugal force of the inner ring 9, and the contact surface 23a of the free end of the weight member 17 again becomes the first contact surface 23a. The two pockets 16 are brought into contact with the inner peripheral surface 16 a and the cage 12 is rotated in the direction of the arrow 25. Since the roller 13 moves while rolling and enters the end portion (wedge portion) of the wedge-shaped space portion 19, the rotational torque of the outer ring 8 reaches the inner ring 9 again, and the outer ring 8 and the inner ring 9 move in the direction of the arrow 25. It is rotated integrally.

  The one-way clutch 5 of the above-described embodiment is a case where the rollers 13 and the weight members 17 are alternately arranged in the circumferential direction of the cage 12. However, like the cage 27 shown in FIG. 6, the rollers 13 and the weight members 17 may be arranged in the pocket 27 in a parallel state in the axial direction. In this case, there is an advantage that each weight member 17 can be arranged without reducing the number of rollers 13.

  In the one-way clutch of this embodiment, when the rotational speed of the inner ring 9 that follows the outer ring 8 that is driven to rotate exceeds a predetermined level, the rotational torque of the outer ring 8 is not automatically transmitted (the clutch is disconnected). When the rotational speed of the inner ring 9 falls below a predetermined level, the rotational torque of the outer ring 8 is automatically transmitted (the clutch is connected). That is, since the rotation speed of the inner ring 9 can be automatically controlled only by the cage moving mechanism (the weight member 17 and the tension spring 24) having a simple configuration, it is not necessary to wastefully increase the strength of the inner ring 9. Thus, the cost of the pulley unit 100 can be reduced.

It is sectional drawing of the pulley unit 100 to which the one way clutch 5 was attached. It is the XX sectional view taken on the line of FIG. 3 is a perspective view of an inner ring 9 and a cage 12. FIG. It is an enlarged view of the principal part of FIG. FIG. 6 is an operation explanatory diagram of the one-way clutch 5. It is a schematic plan view of the holder | retainer 27 of another Example.

Explanation of symbols

100: Pulley unit
1: Auxiliary machine rotary shaft (driven side rotary shaft)
2: Pulley (primary pulley)
5: One-way clutch (one-way clutch mechanism)
8: Outer ring (motor wheel)
9: Inner ring (driven wheel)
12, 27: Cage
13: Roller (wedge member)
14: Cam surface 15, 16, 28: Pocket (pocket-shaped space)
16a: inner peripheral surface
17: Weight member (cage moving mechanism)
17a: proximal end
19: Wedge-shaped space
23: Free end
24: Tension spring (turning restricting means)

Claims (5)

In a pulley unit comprising a driving pulley, a driven rotation shaft, and a one-way clutch mechanism interposed between the driving pulley and the driven rotation shaft,
The one-way clutch mechanism is
A driving wheel rotated integrally with the driving pulley,
A cam surface having a rotational radius that changes along the circumferential direction so as to form a wedge-shaped space between the driven wheel and the driven wheel. The cam surface is fixed to the driven rotary shaft and rotates integrally with the driven rotary shaft. A driven wheel,
Switching between a locked state disposed in the wedge-shaped space portion and being bitten in the wedge-shaped space portion and an unlocked state in which the biting is released, and the rotational speed of the driving wheel is the rotational speed of the follower. A wedge member that is locked into the wedge-shaped space when it falls below,
It has a pocket-shaped space portion that is disposed in an annular space formed between the driving wheel and the driven wheel, is rotatable relative to the driving wheel and the driven wheel, and holds the wedge member. An annular cage;
In a state where the wedge member is in the locked state and the driven wheel is rotating following the driving wheel, the level is changed from a normal rotation state in which the rotational speed of the driving wheel is less than a predetermined level. As the state shifts to a high-speed rotation state that exceeds, the rotational centrifugal force causes the cage to rotate in a direction opposite to the rotation direction, thereby forcing the wedge member from the locked position to the unlocked position. A cage moving mechanism to be moved;
A pulley unit comprising: The cage moving mechanism is
A base end portion is attached to the driven wheel so as to be rotatable along the rotation direction of the driving wheel, and a free end portion enters the pocket-shaped space portion of the cage and is disposed close to the inner peripheral surface thereof. A weight member,
A rotation restricting means for preventing the weight member from rotating in a direction opposite to the rotation direction of the driving wheel in a normal rotation state of the driving wheel;
The pulley unit according to claim 1, further comprising:   The pulley unit according to claim 2, wherein the rotation restricting means is a tension spring attached between a free end portion of the weight member and the driven wheel.   The pulley unit according to claim 2 or 3, wherein the weight members are alternately attached between the wedge members in the circumferential direction.   4. The pulley unit according to claim 2, wherein the weight member is attached in parallel with the wedge member in the axial direction.

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