JPH0988967A - Pulley and ball bearing therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To check or prevent any noise from occurring in time of cold by installing a plastic cage where each axial one side of plural pieces of pocket storing and holding a ball is set to a ring base part and the other side to an opening part respectively, and setting up a guiding part, being guided by an outer ring or inner ring, in this cage. SOLUTION: A cage 2d is equipped with two pockets 3 at circumferential equal positions, and the axial one side is a ring abse part 4 and the other side is an opening part 5, and the peripheral edge is a concave spherical surface. A tongue piece 8 is continuously extended in the outer diametral side tilting direction from the outer diametral side part of a pillar part 7 of this cage 2d, and then a guide part 9 is installed in a tip part outer diameter of the tongue piece 8. When an outer ring 2a is rotated, the cage 2d is dragged around as being pulled by the outer ring 2a by the effect of contact between the guide part 2d and the outer ring 2a and viscosity of an oil film existing between both of them, therefore it comes into contact with a ball 2c by dint of undue contact force. With this contact force, the ball 2c receives revolutional force from a peripheral edge of the pocket 3, whereby its axial behavior is regulated. With this, a self-excited vibration of the ball 2c is restained, and thus any noise in time of cold is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulley, and more particularly to a pulley which is locked to a timing belt of an automobile engine and an accessory driving belt.

[0002]

2. Description of the Related Art Pulleys are arranged in a timing belt of an engine of an automobile, a belt for driving an auxiliary machine, or the like, in order to increase a winding angle of the belt and apply an appropriate tension to the belt. As the pulley, the pulley peripheral surface with which the belt contacts is provided directly on the outer diameter of the outer ring of the ball bearing (shade outer ring).
However, as shown in FIG. 4, a structure in which a pulley main body 11 having a pulley peripheral surface 11c and a ball bearing 12 are fitted and integrated is often used.

The pulley body 11 is made of a steel plate press and has an outer diameter cylindrical portion 11a for hanging a belt and an outer ring 1 of a ball bearing 12.
It has an inner diameter cylindrical portion 11b into which 2a is fitted. The pulley peripheral surface 11c is provided on the outer diameter of the outer diameter cylindrical portion 11a. The ball bearing 12 includes an outer ring 12a fitted to the inner diameter cylindrical portion 11b of the pulley body 11, an inner ring 12b fitted to a fixed shaft (not shown), and a plurality of ball bearings incorporated between the raceways of the inner and outer rings 12b and 12a. The ball 12c, the retainer 12d that holds the ball 12c, and the pair of seals 12e that seals the grease.

In this type of pulley, when the pulley body 11 is rotated by receiving a rotational driving force from the belt, the outer ring 12a of the ball bearing 12 fitted therein rotates together with the pulley body 11.

In the above pulley, the ball bearing 12
The holder 12d of is a so-called snap-on type,
The ball 12c is held by a pocket whose peripheral edge is a concave spherical surface. The diameter of this pocket is usually set by adding a pocket clearance of about 0.2 mm to 0.3 mm to the diameter D of the ball 12c so that the housed and held ball 12c can freely roll. When the bearing is rotating, cage 12
The ball d is brought into contact with and guided by the ball 12c, and rotates as the ball 12c revolves.

[0006]

By the way, when the above pulley is operated in cold weather, a peculiar sound (whistling sound) may be generated depending on the pulley specifications and operating conditions.
This peculiar sound during cold weather, so-called abnormal noise during cold, does not always occur 100% in the market, is affected by temperature and the like, and occurs only in a very limited area in Japan (such as Hokkaido). In addition, it occurs in a very short time (about 1 minute even for a long one) from the start of the engine of the automobile, and then none. Since the abnormal noise during cold has such a complicated property and is difficult to reproduce, the cause of its occurrence has not been clarified yet. Moreover, since pulleys used in automobiles are driven at high temperature and high speed, and durability is one of the important characteristics, it is not possible to take measures to reduce durability. For these reasons, the actual situation is that at present, no effective means that is decisive as a measure against the abnormal noise when the pulley is cold is provided.

Conventionally, as a measure against abnormal noise during cold use, grease having excellent low temperature characteristics (an oil film is formed evenly in the contact portion between the ball and the raceways of the inner and outer rings even in cold weather) is used. Is being considered. This countermeasure is intended to suppress the generation of abnormal noise during cold by improving the lubrication performance of grease during cold weather, and can be expected to have a considerable effect. However, since the viscosity of the grease decreases, there is a concern about lubrication performance at high temperatures, which may lead to a decrease in durability.

Therefore, the present invention intends to provide a means capable of effectively suppressing or preventing the generation of abnormal noise at the time of cold, taking into consideration the durability and the cost while ensuring the function as a pulley. It is a thing.

[0009]

The applicant of the present invention has confirmed several phenomena shown below in a cold abnormal sound reproduction test. (1) The pulley (outer ring) vibrates at high frequency in the axial direction when abnormal noise occurs in the cold state. Further, this high frequency component matches the acoustic frequency of the abnormal noise during cold. (2) This high-frequency component is not recognized when no abnormal noise is generated in the cold. (3) The high frequency component when the abnormal noise is generated in the cold is the end face 18 of the pulley.
It has the same phase at two fixed positions on the 0 ° side.

Although the mechanism of generation of abnormal noise during cold has not been completely clarified yet, from the above verification, the source of abnormal noise during cold is the bearing, and this is also due to the self-excited vibration of the ball. It is thought that That is, in cold weather, unevenness of the oil film on the raceway surface due to increase in viscosity of the base oil of the grease and decrease in consistency are likely to occur, which causes a minute periodic change in the friction coefficient between the ball and the raceway surface. Self-excited vibration occurs on the ball. Then, it is considered that such self-excited vibration of the ball is transmitted to the outer ring and an abnormal noise is generated. In addition, the self-excited vibration of the ball may be transmitted to the pulley main body through the outer ring, resonate with the natural vibration of the pulley main body, be amplified, and may be expanded as a resonance sound.

On the basis of the above inference, the present invention provides a guide guided to the outer ring or the inner ring by the synthetic resin cage in order to effectively suppress the self-excited vibration of the ball as a measure against abnormal noise during cold. A configuration provided with a section is provided.

For example, in the structure provided with the guide portion guided by the outer ring, when the outer ring rotates, the contact between the guide portion of the cage and the outer ring, the viscosity of the oil film interposed between the two, etc.
The retainer is dragged by the rotation of the outer ring and rotates together, and comes into contact with the ball with an appropriate contact force. At this time, due to the contact force of the cage, the ball accommodated in the cage receives a force in the revolution direction from the peripheral edge of the pocket, and the behavior in a direction other than the revolution direction, particularly the behavior in the axial direction is restricted. As a result, the self-excited vibration of the ball is suppressed, and the abnormal noise during cold is suppressed.

For example, in the structure in which the guide portion guided by the inner ring is provided, when the outer ring rotates, the contact between the guide portion of the cage and the inner ring, the viscosity of the oil film interposed between the two, etc.
The cage is dragged by the stop of the inner ring and stops and rotates,
Contact the ball with moderate contact force. At this time, due to the contact force (brake force) of the cage, the ball accommodated in the cage receives a force in the anti-revolution direction from the peripheral edge of the pocket, and the behavior in a direction other than the revolution direction, particularly the behavior in the axial direction, is restricted. To be done.

The contact force of the retainer with respect to the ball, that is, the force exerted on the ball by the retainer in the direction of revolution or in the direction of anti-revolution, suppresses the free movement of the ball, thereby effectively suppressing self-excited vibration. If the force is too large, the bearing function may be adversely affected. In such a case, the guide part of the cage may be partial in the circumferential direction, and an appropriate contact force may be applied to the ball by adjusting the rotating force caused by the turning or stopping. it can.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A pulley shown in FIG. 1 is an idler pulley used for an accessory drive belt of an automobile. It is a pulley body 1 made of a steel plate press and a single row fitted to the inner diameter of the pulley body 1. It is composed of a ball bearing 2. The pulley main body 1 includes a cylindrical portion 1a, a flange portion 1b extending outward from one end of the cylindrical portion 1a, an outer diameter cylindrical portion 1c extending axially from the flange portion 1b, and an inner diameter side from the other end of the cylindrical portion 1a. Extended collar part 1d
A ring consisting of The ball bearing 2 is provided on the inner diameter of the cylindrical portion 1a.
The outer ring 2a is fitted with the outer peripheral surface 1e of the outer diameter cylindrical portion 1c, which is in contact with a belt (not shown). A belt (not shown) comes into contact with the pulley peripheral surface 1e to function as an idler.

As shown enlarged in FIG. 2, the ball bearing 2 is
Outer ring 2 fitted to the inner diameter of the cylindrical portion 1a of the pulley body 1
a, a plurality of balls 2c incorporated between the raceways of the inner ring 2b fitted to a fixed shaft (not shown), the inner and outer rings 2b, 2a, and a cage 2d for holding the balls 2c at equal intervals around the circumference.
And a pair of seals 2e (not shown) for holding grease.

As shown in FIG. 3, the cage 2d is of a so-called snap-on type formed by injection-molding a synthetic resin, for example, and has a plurality of pockets 3 equidistantly arranged on the circumference. The one side in the axial direction is the annular base 4, and the other side in the axial direction is the opening 5. Pocket 3
Is drawn as a concave spherical surface, and the diameter of the pocket 3 is a general value in this type of cage, that is, the ball 2c.
It is set by adding a pocket clearance of about 0.2 mm to 0.3 mm to the diameter D of. However, the diameter of the pocket 3 is not limited to this, and may be optimally set according to the usage conditions.

The space between the pockets 3 is partitioned by the pillar portion 7, and the pillar portion 7
Of the opening 5 by a pair of claws 6 extending in an arc shape from the tip of
Is configured. The opening 5 is set smaller than the diameter of the ball 2c, and the claw 6 is formed thin so as to be elastically deformable. Inner / outer ring 2b,
The tips of the pair of claws 6 are pressed against the ball 2c incorporated between the raceway surfaces of 2a, and the ball 2c is accommodated in the pocket 3 while elastically spreading the opening 5 with the ball 2c. After accommodating the ball 2c, the retainer 2d is prevented from falling off by the pair of elastically restored claws 6.

A tongue piece 8 extends continuously from the outer diameter side portion of the column portion 7 of the cage 2d in the outer diameter side inclination direction, and a guide portion 9 is provided at the outer diameter of the tip end portion of the tongue piece 8. The guide unit 9 is, for example,
The surface is straight in the axial direction and has a curvature corresponding to the curvature in the circumferential direction of the inner diameter surface (guide surface) 2a1 of the outer ring 2a in the circumferential direction. As described above, the area and the number of the guide portions 9 which are partially circumferentially arranged can exert a contact force on the ball 2c to such an extent that the self-excited vibration can be effectively suppressed. , Is set from the viewpoint. In this embodiment, a tongue piece 8 and a guide portion 9 are provided for each pillar portion 7. The pillar portion 7 is provided with a recessed recessed portion 7a in order to enhance the elastic deformability of the tongue piece 8 in the radial direction.

The cage 2d is a ball bearing 2 in the form shown in FIG.
Incorporated in When assembled, the guide portion 9 of the cage 2d elastically contacts the inner diameter surface 2a1 of the outer ring 2a, or a slight guide clearance is formed between them. When the outer ring 2a rotates, the cage 2d is dragged by the rotation of the outer ring 2a due to the contact between the guide portion 9 of the cage 2d and the inner diameter surface 2a1 of the outer ring 2a, the viscosity of the oil film interposed between the two, and the like. The pocket 3 is rotated together, and the peripheral edge of the pocket 3 comes into contact with the ball 2c with an appropriate contact force. At this time, the contact force of the retainer 2d causes the ball 2c to receive a force in the revolution direction from the retainer 2d, and the behavior in a direction other than the revolution direction, particularly the behavior in the axial direction is restricted. This allows the ball 2c
Self-excited vibration is suppressed, and abnormal noise during cold is suppressed.

As the synthetic resin forming the cage 2d as described above, for example, polyamide (PA), polyacetal (POM), polyether sulfone (PES),
In addition to thermoplastic resins such as polyetheretherketone (PEEK), polyamideimide (PAI), polyetherimide (PEI), polyphenylene sulfide (PPS) and thermoplastic polyimide, phenol resin, wholly aromatic polyimide (PI), etc. A thermosetting resin or the like can be used. However, considering that mechanical properties, wear properties, and thermal properties are excellent from the viewpoint of ensuring durability, and that it is desirable that the material is inexpensive and has excellent moldability from the viewpoint of manufacturing cost reduction, Among these synthetic resins, polyamide resin (PA) and polyether ether ketone resin (PEEK) are considered to be preferable, and polyamide resin (PA) is particularly preferable among them. As the polyamide, for example, polyamide 6, polyamide 6-6, polyamide 4-6, polyamide 6-10,
Polyamide 6-12, Polyamide 11, Polyamide 12
Etc. can be used.

Further, in order to assist the lubrication by the internal grease, the polyamide resin may contain a fluorine resin or the like. By the contact between the cage 2d and the ball 2c,
A fluororesin transfer film having good lubricity is formed on the surface of the ball 2c or the like, which is effective in preventing stick-slip which is a factor in inducing self-excited vibration of the ball 2c. Examples of the fluorine-based resin include polytetrafluoroethylene resin (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), tetrafluoroethylene-hexaprolopropylene copolymer resin (FEP), and tetrafluoroethylene. Ethylene-ethylene copolymer resin (ETFE),
Polychlorotrifluoroethylene resin (PCTFE), polyvinyl fluoride resin (PVF) and the like can be used, and among them, PTFE, PFA, FEP, ETF
E is desirable, and PT has the lowest friction coefficient among these.
FE (dynamic friction coefficient 0.10) 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.

In this embodiment, the cage 2d is attached to the outer ring 2
Although it is configured to guide with a, according to the above-mentioned mode,
The cage may be guided by the inner ring.

[0026]

The present invention has the following specific effects. (1) When the bearing rotates, the peripheral edge of the cage pocket comes into contact with the ball with an appropriate contact force, and the behavior of the ball in a direction other than the revolution direction, particularly the behavior in the axial direction, is restricted, so self-excited vibration of the ball is suppressed. As a result, the abnormal noise during cold is effectively suppressed. (2) Since the effects as described above can be obtained regardless of the type of the grease to be filled, there is no fear of lowering the high temperature durability unlike the conventional pulley using grease having excellent low temperature characteristics. (3) Since the generation of abnormal noise during cold can be suppressed or prevented with a simple configuration, it is also advantageous in cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the ball bearing shown in FIG.

FIG. 3 is a plan view (FIG. A: a view from the outer diameter side) showing the vicinity of the pocket of the cage, a bb sectional view in FIG. 3a (FIG. B), and a cc sectional view in FIG. 3a (FIG. C). ).

FIG. 4 is a sectional view showing a conventional pulley.

[Explanation of symbols]

 1 Pulley Main Body 2 Ball Bearing 2c Ball 2d Cage 3 Pocket 4 Annular Base 5 Opening 9 Guide

Claims (5)

[Claims] 1. A cage made of synthetic resin, wherein a plurality of pockets for accommodating and holding balls are formed, and one side in the axial direction of the pocket is an annular base portion, and the other side in the axial direction is an opening, and the cage is an outer ring. Alternatively, a ball bearing for a pulley having a guide portion guided by the inner ring. 2. The ball bearing for pulley according to claim 1, wherein the guide portion is a partial portion in the circumferential direction. 3. A pulley comprising: a pulley main body having a pulley peripheral surface with which the belt comes into contact; and the pulley ball bearing according to claim 1 or 2 fitted to the pulley main body. 4. A guide which is made of synthetic resin and has a plurality of pockets for accommodating and holding balls, wherein one side of the pocket in the axial direction forms an annular base portion, the other side of the pocket in the axial direction forms an opening, and is guided to the outer ring or the inner ring. A retainer for a ball bearing for a pulley, which has a portion. 5. The cage for pulley ball bearings according to claim 4, wherein the guide portion is a partial portion in the circumferential direction.