JPH0925958A - One-way clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a function as a one-way clutch together with a function as a rolling bearing. SOLUTION: A one-way clutch 3 is provided with an inner ring 3a fitted on the outer periphery of a shaft sleeve 2, an outer ring 3b fitted in the inner periphery of a pulley body 1, a plurality of balls 3c interposed between the raceway surface 3a1 of the inner ring 3a and the raceway surface 3b1 of the outer ring 3b and synthetic resin made holder 3d. The holder 3d is fittingly attached to the circumferential groove 3b2 of the outer ring 3b and provided on the wall surface of the pocket side with a cam surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-way clutch that transmits / disengages rotational torque in one direction.

[0002]

2. Description of the Related Art Generally, in a mechanical one-way clutch, a plurality of torque transmission members are interposed between an inner rotating member and an outer rotating member so that the torque transmitting members engage with each other.
Rotational torque is transmitted or cut off in one direction between both members via separation, and is roughly classified into a type using balls or rollers (rollers) as a torque transmission member and a type using sprags. In the former type, a cam surface is provided on one of the outer circumference of the inner rotating member and the inner circumference of the outer rotating member, and the cam surface is formed between this cam surface and the other member.
The latter type engages and disengages a ball (or roller) with respect to the wedge gap in the directional direction. The latter type controls the tilt of a sprag having a cam surface so that the outer circumference of the inner rotary member and the inner circumference of the outer rotary member are controlled. Is engaged and disengaged with respect to. In both types of clutches, when torque is cut off, the torque transmission member separates from both members and becomes free.
The clutch itself does not have the function of supporting radial loads,
Usually, it is often used in combination with a radial bearing.

[0003]

As in the prior art, in the structure in which the one-way clutch and the radial bearing are used together, the axial dimension, weight and cost increase, so that the dimensional, weight and
It is disadvantageous for cost-sensitive applications.

The present invention solves the above-mentioned problems by providing a one-way clutch having a function as a one-way clutch and a function as a rolling bearing with a relatively simple structure. It is intended to further reduce the cost and stabilize the clutch function.

[0005]

SUMMARY OF THE INVENTION A one-way clutch of the present invention comprises an inner rotating member having a raceway surface on the outer circumference, an outer rotating member having a raceway surface on the inner circumference, and a space between both raceway surfaces. A plurality of intervening rolling elements and a cage made of synthetic resin, which is disposed on one raceway surface and has a cam surface forming a wedge gap in one direction with the other raceway surface, are provided for the wedge gap of the rolling element. The rotation torque is transmitted / blocked through engagement / disengagement.

The retainer may be a split ring having one split or a partial ring aligned in the circumferential direction.

Further, it is preferable that the retainer is fitted in a circumferential groove provided on one raceway surface. In this case, as the shape of the cage, an annular portion that is fitted and fitted into the circumferential groove, a plurality of pillar portions that extend from the annular portion to the other raceway surface side, and are adjacent to each other in the annular portion and the circumferential direction. It is preferable to have a shape that is surrounded by the pillar portion and has a pocket capable of accommodating the rolling element, and a cam surface that is provided on the pocket-side wall surface of the annular portion and that forms a wedge gap in one direction with the other raceway surface.

As the inner rotating member, the outer rotating member and the rolling elements, the rolling bearing parts can be used as they are or after being slightly processed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a one-way clutch used for an alternator pulley of an automobile will be described below.

The alternator pulley shown in FIG. 1 mainly comprises a pulley body 1 having a belt engaging groove 1a provided on the outer periphery thereof and a one-way clutch 3 interposed between the pulley body 1 and the shaft sleeve 2. As an element, receives the rotational power from the crankshaft of the engine via the transmission belt (V belt),
This is input to an input shaft (which is inserted into the inner circumference of the shaft sleeve 2) of an alternator (not shown).
As will be described later, in such a belt transmission mechanism, the one-way clutch 3 has a slippage of the conduction belt (the peripheral speed of the conduction belt varies due to the variation of the angular velocity on the driving side (crankshaft side) in the belt transmission mechanism. (Due to a difference in peripheral speed with respect to the inertial rotation), it prevents the abrasion of the conductive belt.

The one-way clutch 3 includes an inner ring 3a fitted to the outer circumference of the shaft sleeve 2, an outer ring 3b fitted to the inner circumference of the pulley body 1, a raceway surface 3a1 of the inner ring 3a and a raceway surface 3b1 of the outer ring 3b. Balls 3c, balls 3 interposed between
Synthetic resin cage 3d for holding c and outer ring 3
It is composed of a pair of seal members 3e attached to the inner diameters of both ends of b. The outer ring 3b is fixed by a retaining ring 4 fitted to the inner circumference of the pulley body 1 so as not to come off.

In this embodiment, the outer ring 3b is obtained by dividing the bearing outer ring of the standard deep groove ball bearing into two along the bearing center line, and providing the circumferential groove 3b2 at the groove bottom of the raceway surface 3b1. . The outer ring 3b is divided into two parts because the ball 3
This is for facilitating the assembling of c between the raceway surfaces 3a1 and 3b1, and the reason why the circumferential groove 3b2 is provided on the raceway surface 3b1 is to mount the retainer 3d described below.
As the inner ring 3a, the bearing inner ring of the standard deep groove ball bearing is used as it is.

As shown in FIG. 2, the cage 3d is made of synthetic resin, and has an annular portion 3d1 fitted and fitted in the circumferential groove 3b2 of the outer ring 3b, and continuously extending from the annular portion 3d1 to the inner diameter side. A plurality of pillars 3d2, a pocket 3d3 formed by being surrounded by the annular portion 3d1 and the pillars 3d2 circumferentially adjacent to each other, and a cam surface 3d4 provided on the wall surface of the annular portion 3d1 on the pocket side. ing. In addition, in this embodiment, the cage 3d is a split ring having one split port 3d5, and can freely expand or contract when an external force is applied from the inner diameter side or the outer diameter side, and elastically recovers when the external force is removed. Return to the state of. The outer diameter D of the retainer 3d in the natural state is set to be approximately the same as the groove bottom diameter of the circumferential groove 3b2 of the outer ring 3b.
“Similar” includes the case of being apparently the same (within the range of manufacturing error), the case of being slightly large, and the case of being slightly small. The width of the cage 3d may be slightly smaller than the width of the circumferential groove 3b2.

As shown enlarged in FIG. 3, the cam surface 3d4 of the cage 3d forms an angle with the tangent line L at the contact point C1 of the ball 3c with the raceway surface 3a1 (contact point C2 with the raceway surface 3b1). It is a tapered surface inclined by θ. This inclination angle θ may be set based on a general value for a one-way clutch. Since the cam surface 3d4 has such a shape, a wedge gap reduced in one direction (counterclockwise rotation direction in the figure) is formed between the cam surface 3b4 and the raceway surface 3a1.

FIG. 3 shows a state in which the ball 3c is separated from the wedge gap. In this state, the ball 3c
c rolls while contacting raceway surfaces 3a1 and 3b1 at points C1 and C2, and functions as a normal bearing rolling element. Therefore, the rotation torque is blocked between the outer ring 3b and the inner ring 3a, and the outer ring 3b runs idle with respect to the inner ring 3a. At the same time, the radial load from the outer ring 3b is supported by the plurality of balls 3c. On the other hand, from the state shown in the figure, the ball 3c relatively moves in the counterclockwise direction with respect to the retainer 3d to move the cam surface 3d.
When 4 is pressed, the cage 3d slightly expands in diameter and the annular portion 3
The wall surface (outer diameter D) on the side opposite to the pocket of d1 is in pressure contact with the groove bottom of the circumferential groove 3b2. Then, when the ball 3c further moves (or tries to move relatively) to the left in the leftward rotation direction from this state, the ball 3c moves to the cam surface 3d4 and the raceway surface 3.
The ball 3c is locked by completely engaging the wedge gap formed with a1. As a result, the rotational torque from the outer ring 3b is transmitted through the route of the outer ring 3b → the cage 3d → the ball 3c → the inner ring 3a, and the inner ring 3a rotates integrally with the outer ring 3b.

The one-way clutch 3 retains the engagement and disengagement of the ball 3c with respect to the wedge gap as described above.
It is configured to be automatically carried out by rotating the outer ring 3b of d with rotation. As described above, the outer diameter D of the retainer 3d in the natural state (the state in which no force is received from the balls 3c) is set to be approximately the same as the groove bottom diameter of the circumferential groove 3b2. Therefore, when the outer ring 3b rotates, the annular portion 3d
1 due to the contact between the circular groove 3b2 and the circular groove 3d
1 and the circumferential groove 3b2, the viscosity of the oil film formed between the cage 3d causes the retainer 3d to receive a force in the rotational direction from the outer ring 3b and rotate together. For example, in FIG. 3, when the outer ring 3b rotates in the left rotation direction, the cage 3d is dragged by the rotation of the outer ring 3b and rotates together with the left rotation direction. Therefore, the balls 3c move relative to the retainer 3d in the right rotation direction and separate from the wedge gap, and the rotation torque is blocked. From this state, when the rotation of the outer ring 3b is switched to the right rotation direction, the cage 3d is dragged by the rotation of the outer ring 3b and is rotated together with the right rotation direction. Therefore, the ball 3c
Moves relative to the retainer 3d in the counterclockwise rotation direction to engage with the wedge gap, and the rotational torque is transmitted. That is, by the change in the relative rotation direction of the outer ring 3b with respect to the inner ring 3a,
The clutch torque transmission / disconnection automatically switches.

The above operation will be described in the context of the alternator pulley. When the peripheral speed of the conductive belt decreases due to the decrease in the angular velocity of the crankshaft, the input rotation of the outer wheel (driving side) is different from the inertial rotation of the inner wheel (driven side). Slightly delayed. At this time, if the outer ring and the inner ring were connected to each other, the input from the inner ring to the outer ring would be reversed and a gap between the peripheral speed of the conductive belt and the rotation of the pulley body would be generated, which would cause the conductive belt to move to the pulley body. Slip against. The one-way clutch 3 cuts off torque transmission between the outer ring 3b and the inner ring 3a when the outer ring 3b is delayed in rotation, that is, when the outer ring 3b is rotated relatively to the left in FIG. By idling it (by blocking the reverse input from the inner ring 3a), slip due to a decrease in the peripheral speed of the conductive belt is prevented and the wear thereof is suppressed. When the torque is cut off, the one-way clutch 3 functions as a rolling bearing,
It also plays the role of supporting the belt load of the conductive belt. From this state, when the outer ring 3b rotates relative to the inner ring 3a in the right rotation direction, the clutch automatically switches to torque transmission. That is, the torque transmission / disengagement of the clutch is automatically switched by a change in the angular velocity of the crankshaft and a change in the peripheral velocity of the transmission belt.

Since the switching responsiveness of the one-way clutch 3 depends on the accompanying rotational force of the retainer 3d, the shape of the cam surface 3d4 (tilt angle θ, etc.), the clutch clearance, etc. It is recommended to set the optimum value according to the situation.

Examples of the synthetic resin forming the cage 3d, which is the main element of the clutch as described above, include polyamide (PA), polyacetal (POM), polyether sulfone (PES), and polyether ether ketone ( PEEK), polyamideimide (PAI), polyetherimide (PEI), polyphenylene sulfide (PPS), thermoplastic polyimide and other thermoplastic resins, as well as phenolic resins, wholly aromatic polyimide (PI) and other thermosetting resins, etc. Can be used. However, from the viewpoint of ensuring durability, it has excellent mechanical properties, wear properties, and thermal properties. When the retainer 3d is a complete ring (without a split), the amount of contraction required for the clutch element is reduced. It is desirable to have good sliding characteristics because it has elasticity to the extent that diameter expansion can be expected, and it is expected to slide with the circumferential groove 3b2 when spinning, and from the viewpoint of manufacturing cost reduction. Considering that it is desirable to be a material that is inexpensive and has excellent moldability, polyamide resins (PA) and polyether ether ketone resins (PEEK) are considered to be preferable among these synthetic resins, and among them, polyamide is preferable. Resin (PA) is considered to be particularly preferred. Examples of polyamides include polyamide 6, polyamide 6-6, polyamide 4-6, and polyamide 6-1.
0, polyamide 6-12, polyamide 11, polyamide 12, etc. can be used.

Further, in order to further improve the sliding characteristics, the above polyamide resin may contain a fluorine resin or the like. Examples of the fluorine-based resin include polytetrafluoroethylene resin (PTFE) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (P
FA), using tetrafluoroethylene-hexapropropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene resin (PCTFE), polyvinyl fluoride resin (PVF), etc. And among them, PT
FE, PFA, FEP, and ETFE are desirable, and PTFE having the lowest friction coefficient (dynamic friction coefficient 0.1
0) is particularly desirable.

Further, various fillers may be blended within a range that does not impair the effects of the present invention. Fillers include glass fiber, carbon fiber, aramid fiber, potassium titanate whisker, wollastonite, aluminum borate whisker,
Reinforcing material such as calcium sulfate whisker, inorganic powder such as molybdenum disulfide, graphite, carbon, calcium carbonate, talc, mica, kaolin, iron oxide, glass beads, phosphate compound, polyimide resin, aromatic polyester resin, polyether Various fillers such as resin powder such as ketone resin, polyphenylene sulfide resin, and silicone resin, and internal lubricant such as silicone oil, fluorine oil, wax, and stearic acid compound can be exemplified.

As a method of molding the above polyamide resin,
Although various known molding methods such as injection molding, extrusion molding, monomer casting, and powder molding can be adopted, injection molding is preferable in consideration of low cost, work efficiency, and the like. Further, heat treatment and heat treatment may be performed after the molding. The heat treatment is performed to relieve the residual stress of the molded product, enhance dimensional stability, enhance crystallinity, and enhance mechanical properties. As the heat treatment agent, water, liquid paraffin, quenching oil or the like can be used. The tempering treatment is a treatment for forcibly absorbing water up to the equilibrium water content in a short time in order to enhance dimensional stability. It is recommended to use boiling water or an aqueous solution of potassium acetate. Further, after molding, the outer peripheral surface and the inner peripheral surface may be subjected to grinding processing or the like.

As the synthetic resin forming the cage 3d,
In addition to the synthetic resin exemplified above, a copuna resin can also be used.

In addition to the above-exemplified synthetic resins, synthetic resins having physical properties (sliding characteristics, mechanical characteristics, etc.) that are the same as or better than the above-mentioned synthetic resins can be adopted.

In the embodiment shown in FIG. 4, the cage 3d is constructed by aligning a plurality of partial rings 3d 'in the circumferential direction. Each partial ring 3d 'has an annular portion 3d'1 fitted and fitted in the circumferential groove 3b2 of the outer ring 3b, two pillar portions 3d'2 extending inward from the annular portion 3d'1, and an annular portion. A pocket 3d'3 surrounded by 3d'1 and two pillars 3d'2 and a cam surface 3d'4 provided on the pocket-side wall surface of the annular portion 3d'1 are provided. . When the cam surface 3d'4 is pushed by the ball 3c, each partial ring 3d 'moves slightly to the outer diameter side, and the wall surface of the annular portion 3d'1 on the side opposite to the pocket is pressed against the groove bottom of the circumferential groove 3b2. . The other basic operational effects are the same as those of the above-described embodiment, so the description thereof will be omitted.

In the embodiment shown in FIG. 5, in the structure shown in FIG. 4, the column portion 3 on the side opposite to the wedge gap of each partial ring 3d 'is provided.
The spring member 3e is attached to d'2. The spring member 3e includes a U-shaped mounting portion 3e1 that is fitted to the column portion 3d′2, and a tongue piece 3e2 that is curved and continuous from the mounting portion 3e1. Since the tongue piece 3e1 of the spring member 3e constantly contacts the ball 3c and presses the ball 3c toward the wedge gap side, the switching response to torque transmission is better than that of the configuration shown in FIG.

In the embodiment shown in FIG. 6, a seal member such as an O-ring 5 is interposed between the outer circumference of the outer ring 3b and the inner circumference of the pulley body 1. The O-rings 5 are fitted in annular grooves provided on the outer periphery of the outer ring 3b, and one O-ring 5 is arranged on each of the left and right sides of the divided portion of the outer ring 3b. This is effective in preventing the lubricant from leaking from the divided portion of the outer ring 3b.

In FIG. 7, the raceway surface 3b1 of the outer ring 3b has a Gothic arch shape. Ball 3c is raceway surface 3
It makes angular contact with b1 at two points C3 and C4 and does not make contact with the groove bottom portion where the circumferential groove 3b2 is provided. At the time of rolling, the ball 3c does not come into contact with the inlet edge portion of the circumferential groove 3b2, which is effective as a means for improving durability.

The embodiment shown in FIG. 8 has an inner ring 3a and an outer ring 3b.
And the insertion grooves 3g and 3f are provided in each. The insertion groove 3g communicates with the raceway surface 3a1 from one end surface of the inner ring 3a, and the insertion groove 3f communicates with the raceway surface 3b1 from one end surface of the outer ring 3b. The balls 3c can be inserted from the receiving grooves 3g and 3f between the raceway surfaces 3a1 and 3b1. Therefore, the outer ring 3b of this embodiment has an integral structure instead of the above-described two-divided structure.

The embodiment shown in FIG. 9 uses rollers (rollers) 3c 'as rolling elements. The outer ring 3b 'is
The bearing outer ring of the standard cylindrical roller bearing is divided into two along the center line of the bearing, and the raceway surface 3b'1 is provided with a circumferential groove 3b'2. The circumferential groove 3b'2 is located substantially at the center of the raceway surface 3b'1 and is wider than the configuration of the above-described embodiment, and correspondingly, the width of the cage 3d is also increased. Therefore, it can be expected that the load capacity of the radial load is increased by using the rollers 3c 'as the rolling elements and the capacity of the braking torque is increased by the strength of the cage 3d. As the inner ring 3a ', the bearing inner ring of the standard cylindrical roller bearing is used as it is.

The present invention is not limited to the structure exemplified above. For example, the raceway surface may be directly formed on the inner circumference of the pulley main body, the shaft sleeve or the outer circumference of the mating shaft, and the cage having another shape. (For example, one without a pillar portion) may be used, or the retainer may be a complete ring having no slit (in this case, the material elasticity of the retainer is used to perform the required expansion / contraction). According to the above-mentioned structure, the cage may be provided with a circumferential groove on the raceway surface of the inner ring or the like (the raceway surface on the side where the cage is mounted. However, the present invention is based on the circumferential groove of the raceway surface. It is not limited to the configuration for fitting and fitting). Further, the one-way clutch of the present invention is not limited to a belt transmission mechanism such as an alternator pulley, but can be widely used for a general mechanism for transmitting or interrupting rotational torque in one direction.

[0032]

The present invention has the following effects.

(1) The one-way clutch of the present invention has a function as a one-way clutch and a function as a rolling bearing in spite of its relatively simple structure, so that it can be compared with the conventional structure used in combination with the radial bearing. In addition, the axial dimension can be reduced, the weight can be reduced, and the cost can be reduced. In particular, it is suitable for applications with severe dimensional, weight, and cost constraints.

(2) Since the cage is made of synthetic resin,
Excellent workability and cost efficiency. In particular, when the cage is formed by injection molding, etc., it is extremely advantageous in terms of workability, cost, and mass productivity, and the cam surface is smooth because there is no shearing of the material compared with the case of machining. The rotation torque transmission function and cutoff function are stable.

(3) Since the phenomenon of biting between the rolling elements and the cam surface of the cage (biting phenomenon) does not occur, the clutch function is ensured. In addition, since the impact force at the time of sudden switching to torque transmission and the vibration transmitted through the inner rotating member and the outer rotating member are absorbed by the elasticity of the cage made of synthetic resin, vibration characteristics and acoustic characteristics are improved. Is also excellent.

(4) As the inner rotating member, the outer rotating member, and the rolling elements, standard rolling bearing parts are used as they are, or
Since it can be used after being slightly processed, it is extremely advantageous in terms of cost.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an alternator pulley according to an embodiment (FIG. 1A) and a transverse sectional view of a one-way clutch (FIG. 1B).

FIG. 2 is a side view of a cage.

FIG. 3 is an enlarged sectional view showing a peripheral portion of a cam surface in FIG.

FIG. 4 is a cross-sectional view of a one-way clutch according to another embodiment.

FIG. 5 is a cross-sectional view (FIG. A) of a one-way clutch and a perspective view (FIG. B) of a spring member according to another embodiment.

FIG. 6 is a vertical cross-sectional view of an alternator pulley according to another embodiment.

FIG. 7 is an enlarged sectional view showing an outer ring raceway surface of a one-way clutch according to another embodiment.

FIG. 8 is a vertical sectional view (FIG. A) of an alternator pulley according to another embodiment and a horizontal sectional view (FIG. B) of a one-way clutch.

FIG. 9 is a longitudinal sectional view (FIG. A) and a transverse sectional view (FIG. B) of a one-way clutch according to another embodiment.

[Explanation of symbols]

 3 1-way clutch 3a Inner ring 3b Outer ring 3c Ball 3d Retainer 3a1 Raceway surface 3b1 Raceway surface 3b2 Circumferential groove

Claims (6)

[Claims] 1. An inner rotating member having a raceway surface on its outer circumference, an outer rotating member having a raceway surface on its inner circumference, a plurality of rolling elements interposed between both raceway surfaces, and one raceway surface. And a cage made of synthetic resin having a cam surface that forms a wedge gap in one direction with the other raceway surface, and the transmission of rotational torque through engagement / disengagement of the rolling element with respect to the wedge gap. A one-way clutch characterized by disengagement. 2. The one-way clutch according to claim 1, wherein the retainer is a split ring having one split. 3. The one-way clutch according to claim 1, wherein the retainer is a partial ring aligned in the circumferential direction. 4. The cage according to claim 1, wherein the cage is fitted in a circumferential groove provided on the one raceway surface.
Two or three one-way clutch. 5. The retainer is adjacent to the annular portion and the circumferential direction, the annular portion being fitted to the circumferential groove, and the plurality of pillar portions extending from the annular portion toward the other raceway surface side. It is characterized in that it has a pocket that is surrounded by a pillar portion and that can accommodate a rolling element, and a cam surface that is provided on the wall surface of the annular portion on the pocket side and that forms a wedge gap in one direction with the other raceway surface. The one-way clutch according to claim 4. 6. The one-way clutch according to claim 1, wherein the inner rotating member, the outer rotating member, and the rolling elements are rolling bearing parts.