JP2004162921A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce vibration and noise of a ball bearing by ensuring lubrication in a slide contact part of a cage 18 and a ball 5 sufficiently. <P>SOLUTION: Chamfering 17 is applied to a peripheral fringe part of an opening of each pocket 8. This chamfer 17 is a curved face having a circular arc cross section shape, and radius of curvature of the cross section shape of the chamfer 17 is 1 to 20 % of outside diameter of the ball 5 to take lubricating oil into a rolling contact part easily in order to solve the problem. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an improvement in a rolling bearing used for various types of rotating machinery , and relates to a rolling bearing capable of reducing vibration and noise of the rolling bearing by sufficiently securing lubrication of a sliding contact portion between a cage and a rolling element. It is intended to be realized.

Ball bearings as shown in FIG. 4 , for example, are widely used as rolling bearings for supporting various rotating parts such as bearing parts of various rotating machinery. In this ball bearing, an inner race 2 having an inner raceway 1 on an outer peripheral surface and an outer race 4 having an outer raceway 3 on an inner peripheral surface are arranged concentrically with each other, and a plurality of races are provided between the inner raceway 1 and the outer raceway 3. The balls 5, 5 are provided so as to roll freely. In the illustrated example, both the inner raceway 1 and the outer raceway 3 are of a deep groove type. Further, the plurality of balls 5, 5 are rotatably held in pockets 8, 8 provided in the holder 6.

The retainer 6 constituting the ball bearing shown in FIG. 4 is called a corrugated press retainer, and a pair of corrugated annular elements each obtained by press forming a metal plate material. 9 and 9 are combined. These two elements 9, 9 have recesses 8a, 8a for forming the pockets 8, 8 at a plurality of positions in the circumferential direction, respectively. Then, the pair of elements 9, 9 are butted at portions deviating from the recesses 8 a, 8 a, and these portions are connected and fixed by a plurality of rivets 10, and the pockets 8 are formed at a plurality of positions in the annular direction in the circumferential direction. 8 as a retainer 6. An inner surface intermediate portion of each of the recesses 8a, 8a is a holding concave surface 11 having a curvature radius slightly larger than a curvature radius of an outer surface of each of the balls 5, 5 and having an arc-shaped cross section. Therefore, when the pair of elements 9 and 9 are abutted, the recesses 8a and 8a are combined to form pockets 8 and 8.

A cage 6a called a crown-shaped cage shown in FIG. 5 has balls 5, 5 ( see FIG. 4 ) at a plurality of circumferential positions of an annular main portion 7 made of synthetic resin or the like . There are provided pockets 8 and 8 for holding the rolling freely. In the case of such a crown-shaped retainer 6a, each of the pockets 8, 8 is provided with one side surface of a pair of elastic pieces 12, 12, which are arranged at an interval from each other on the main portion 7, and the main portion 7, 5 (vertical direction in FIG. 5 ), and spherical concave portions 13, 13 provided between the pair of elastic pieces 12, 12 on one surface (upper surface in FIG. 5 ). The radius of curvature of the concave portions 13, 13 is slightly larger than the radius of curvature of the outer surface of the ball 5. One side surface of these elastic pieces 12 and 12 and concave portions 13 and 13 constitute a holding concave surface.

When assembling the ball bearing, each of the balls 5, 5 is connected to the pair of elastic pieces 12, 12 constituting each of the pockets 8, 8 while elastically expanding the interval between the leading edges thereof. Push between the elastic pieces 12,12. The retainer 6a holds the balls 5 and 5 in the pockets 8 and 8 in such a manner, so that the balls 5 and 5 are connected to the inner raceway 1 and the outer raceway 3 ( see FIG. 4 ) . Between them, so that they can roll freely.

When the above-described cage 6 or the ball bearing provided with the above-described cage 6a is used, the relative rotation between the inner ring 2 and the outer ring 4 is made free with the rolling of the plurality of balls 5,5. . At the time of this relative rotation, the plurality of balls 5, 5 revolve around the inner ring 2 while rotating. The cages 6 and 6a rotate around the inner ring 2 at the same speed as the revolution speed of the balls 5 and 5.

Lubricant such as grease or other lubricating oil is filled or continuously supplied to a portion between the outer peripheral surface of the inner ring 2 and the inner peripheral surface of the outer ring 4 so that the relative rotation is smoothly performed. . In addition, vibration and noise are not generated in the ball bearing, and a failure such as seizure is prevented. In some ball bearings, the sealing member such as sealing plates and the shield plate, closing the openings at both ends of the space between the outer peripheral surface and the inner peripheral surface of the outer ring 4 of the inner ring 2, the lubricant from this space In some cases, leakage or prevention of foreign matter such as dust into this space may be prevented. However, FIG. 4 shows a ball bearing without such a sealing member.

  In the case of a ball bearing incorporating the retainers 6 and 6a as described above, even if a required amount of lubricant is filled or supplied, vibrations are induced in the retainers 6 and 6a, and the retainers 6 and 6a are incorporated. In some cases, noise or vibration called cage sound is generated in the ball bearing. Such vibrations of the cages 6 and 6a cause a large amount of movement of the cages 6 and 6a with respect to the balls 5 and 5, and therefore, the vibration between the balls 5 and 5 as rolling elements and the cages 6 and 6a. Occurs based on the sliding friction of Conventionally, in order to suppress the generation of such cage sound, the gap between the inner surfaces of the pockets 8, 8 and the rolling surfaces of the balls 5, 5 has been reduced, so that the cages 6, 6a for the balls 5, 5 have been reduced. The amount of movement of the cage is reduced, and the occurrence of cage sound is suppressed.

However, simply reducing the amount of movement of the cages 6 and 6a with respect to the balls 5 and 5 causes cage noise due to the inner peripheral shape of the pockets 8 and 8 of the cages 6 and 6a. Concerning the reason for this will be described with reference to FIG 6-7. As shown in FIGS. 6 to 7 , sharp (greater curvature) corner portions 15, 15 are present at the opening peripheral portions 14, 14 of the pockets 8 of the retainers 6, 6 a . Resistance to lubricant flow. That is, both the corrugated cage 6 made by press-molding a metal plate and the crown-shaped cage 6a made by injection-molding a synthetic resin have the opening peripheral portions 14, 14 of the pockets 8, 8. Has a sharp edge due to burrs or the like, the curvature of each of the corners 15 is very large.

Therefore, if the gap between the inner surface of the pocket 8 and the rolling surface of the ball 5 is reduced to suppress the cage sound, the rolling surface of the ball 5 and the holding concave surface 11 (in the case of the cage 6 shown in FIG. In the retainer 6a shown in Fig. 5 , it is difficult for the lubricant to flow into the gap 16 between the elastic pieces 12, 12 and one side surface and the concave portion 13). That is, the lubricant that tries to enter the gap 16 from the surrounding space with the rolling of the ball 5 is scraped off by the corners 15, 15, and becomes difficult to enter the gap 16. For this reason, a sufficient amount of lubricant is not taken in the gap 16 between the holding concave surface 11 and the rolling surface of the ball 5, and the friction of the sliding contact portion between the cages 6, 6a and the ball 5, 5 is reduced. Vibration cannot be sufficiently suppressed, causing vibration and noise.

The present invention has been made in view of the above-described circumstances, and has been made to reduce the vibration and noise of a rolling bearing by ensuring sufficient lubrication of a sliding contact portion between a cage and a rolling element.

Any of the rolling bearings of the present invention, like the above-described conventional rolling bearing , has an inner ring having an inner ring raceway on the outer peripheral surface, an outer ring having an outer ring raceway on the inner peripheral surface, and a space between these inner raceways and the outer raceway. The vehicle includes a plurality of rolling elements rotatably provided, and a retainer for rotatably holding the rolling elements . The retainer is formed in a ring shape as a whole so as to freely roll a plurality of rolling elements, and has pockets at a plurality of positions in a circumferential direction.
In particular, in the rolling bearing according to the first aspect, cylindrical portions are formed at both ends of the pockets, and the cylindrical portions are formed at the inner edge of each cylindrical portion and at the center of each pocket. Both end edges of the spherical concave portion are continuous by chamfering .
Further, in the rolling bearing according to the second aspect, in the opening at both ends of each pocket, a mortar-shaped inclined surface whose inner diameter increases toward the opening peripheral portion of each pocket is formed, The inner edge of each of these inclined surfaces and both edges of a spherical concave portion formed at the center of each pocket are continuous by chamfering.

The operation itself when the cage incorporated in the rolling bearing of the present invention configured as described above rotatably holds a plurality of rolling elements is the same as that of the cage incorporated in the conventional rolling bearing described above. Same as in the case.
In particular, in the case of the rolling bearing of the present invention, the lubricant is easily taken into the gap between the inner surface of the pocket and the rolling surface of the rolling element, and the rolling surface of the rolling element and the inner periphery of the pocket of the cage are easily taken. The lubrication state of the sliding contact portion with the surface is improved. That is, based on the presence of the chamfer formed at the peripheral edge of the opening of each pocket, the flow of the lubricant into the pocket is not prevented, and the lubricant easily flows into the pocket. For this reason, vibration and noise called cage sound hardly occur.
As a result, in the rolling bearing of the present invention, generation of cage noise is suppressed, and a low-vibration, low-noise rolling bearing can be obtained. Further, in the case of the rolling bearing of the present invention, the friction of the sliding contact portion between the rolling surface of the rolling element and the inner peripheral surface of the pocket of the cage is reduced, so that the wear resistance of the cage can be improved.

In the case of carrying out the present invention, preferably, the rolling element is a ball, and positioning of the retainer in the radial direction is performed by ball guide based on engagement with the ball. Further, the chamfer is a curved surface having a circular cross section, and the radius of curvature of the cross section of the chamfer is 1 to 20% of the outer diameter of the ball.
More preferably, the radius of curvature of the cross-sectional shape of the chamfer is 2 to 16% of the outer diameter of the ball. More preferably, the radius of curvature of the cross-sectional shape of the chamfer is 5 to 15% of the outer diameter of the ball.

FIG. 1 shows a first embodiment of the present invention. This embodiment is intended that the present invention is applied to a crown type cage shown in FIG. 5. Similar to the above-mentioned conventional cage 6a ( see FIG. 5 ), the cage 18 is provided at an annular main portion 7 made of synthetic resin and at a plurality of circumferential positions of the main portion 7 and has an inner side. And a plurality of pockets 8 for holding the balls 5 as rolling elements one by one so as to freely roll. Each of these pockets 8 is formed by a pair of elastic pieces 12 and 12 (see FIG. 5 ) which are arranged at an interval from each other in the main part 7 and one side in the axial direction of the main part 7 (the upper surface in FIG. And a concave portion 13 provided between the pair of elastic pieces 12. One side of the concave portion 13 and the elastic piece 12 is in a spherical concave surface having a radius of curvature R ₁₃ is slightly larger than the radius of curvature r of the rolling surface of the ball 5 to be held the cage 18. The concave portion 13 and one side surface of the pair of elastic pieces 12 constitute a holding concave surface for holding the ball 5 in a freely rolling manner. Further, in the case of the retainer 18 of the present embodiment , cylindrical portions 19, 19 are formed at both end openings of the pockets 8, and the inner edges of the cylindrical portions 19, 19 and the pockets 8 are formed. Both end edges of the spherical concave portion 13 formed at the central portion are continuous by chamfers 17 and 17, respectively. The retainer 18 having the pockets 8 provided with the chamfers 17 and 17 is formed by injection molding of a synthetic resin. These chamfers 17, 17 are formed at the time of the injection molding. However, in some cases, the chamfers 17, 17 may be formed by barrel processing after the injection molding. Furthermore, the shapes of the chamfers 17 formed at the time of injection molding can be finished by barrel processing.

In the rolling bearing of the present embodiment incorporating the cage configured as described above, the operation itself when the cage holds the plurality of balls 5 in a freely rolling manner is incorporated in the above-described conventional rolling bearing . It is the same as in the case of the cage. In particular, in the case of the cage incorporated in the rolling bearing of the present embodiment, the rolling surface of the ball 5 and one side surface of the pair of elastic pieces 12, lubricant to the point of entering into the gap 16 between the concave portion 13, so scraping without taken in apertures peripheral portions 14 partially enters efficiently into the gap 16. For this reason, a sufficient amount of lubricant is taken into the gap 16 between the one side surface of the pair of elastic pieces 12, 12 and the concave surface portion 13 and the rolling surface of the ball 5, and furthermore, the lubricant is introduced into the gap 16. The agent can be held for a long time. As a result, the frictional vibration of the sliding contact portion between the retainer 18 and the ball 5 can be sufficiently suppressed, and the possibility of inducing vibration or noise called retainer sound is reduced.
In any case, each of the chamfers 17 is a curved surface having a circular cross section. The radius of curvature of the cross-sectional shape of each of the chamfers 17 is set to 1 to 20% of the outer diameter of the ball 5 held in the pocket 8. More preferably, the radius of curvature of the cross-sectional shape of each of the chamfers 17, 17 is 2 to 16% of the outer diameter of the ball 5, and more preferably, the radius of curvature of the cross-sectional shape of each of the chamfers 17, 17 is 5 5 to 15% of the outer diameter of In the case of this embodiment, the lubricant is efficiently taken into the gap 16 between the rolling surface of the ball 5 and the concave portion 13 of the pocket 8 through the chamfers 17 and 17 as described above. The possibility of inducing vibration and noise called cage sound is reduced.

FIG. 2 shows a second embodiment according to the present invention. In the case of this embodiment, mortar-shaped inclined surfaces 20, 20 whose inner diameters increase toward the opening peripheral portion of the pocket 8 are formed at both end openings of the pocket 8, and these inclined surfaces 20, 20 are formed. And the two end edges of the spherical concave portion 13 formed at the center of the pocket 8 are continuous by chamfers 17a, 17a, respectively. The retainer 18a having the pockets 8 provided with the chamfers 17a, 17a is formed by injection molding of a synthetic resin as in the case of the first embodiment. The chamfers 17a, 17a are formed at the time of the injection molding. However, in some cases, the chamfers 17a, 17a may be formed by barrel processing after the injection molding. Further, the shapes of the chamfers 17a, 17a formed at the time of injection molding can be finished by barrel processing.
In any case, each of the chamfers 17a, 17a is a curved surface having a circular cross section. The radius of curvature of the cross-sectional shape of each of the chamfers 17a is set to 1 to 20% of the outer diameter of the ball 5 held in the pocket 8. More preferably, the radius of curvature of the cross-sectional shape of each of the chamfers 17a, 17a is 2 to 16% of the outer diameter of the ball 5, and more preferably, the radius of curvature of the cross-sectional shape of each of the chamfers 17a, 17a is 5 to 15% of the outer diameter of In the case of this embodiment as well, the lubricant is efficiently taken into the gap 16 between the rolling surface of the ball 5 and the holding concave surface 13 of the pocket 8 through the chamfers 17a, 17a. And the likelihood of inducing vibrations and noise, referred to as "sound", is reduced.

An experiment conducted to know the effect of the radius of curvature of chamfering on the generation of cage sound will be described.
In this experiment , the ratio of the radius of curvature of the chamfers 17 , 17 to the outer diameter (diameter) of the ball 5 was varied using the retainer 18 as in the first embodiment shown in FIG. The effect on the cage sound that sometimes occurred was measured. The test conditions are as follows.
(1) Bearing used: Deep groove ball bearing with nominal number 6202 (outer diameter 35 mm, inner diameter 15 mm, width 11 mm)
Cage used: outer diameter 25.5 mm, inner diameter 21.5 mm, width 5.80 mm, crown-shaped cage guided by balls, central angle θ of concave portion 13 (see FIG. 1 ): 46 degrees
(2) Operating conditions Lubrication conditions: 40% volumetric filling of ether urea grease with a kinematic viscosity of 100 cst in a fillable space Rotational speed: 4000 rpm
Radial load: 100kgf
Thrust load: 50kgf
Ambient temperature and humidity: 0 ° C, 20%

The relationship between the radius of curvature of each of the chamfers 17 and the loudness of the cage noise generated during operation was determined under the above-described conditions, and the results shown in FIG. 3 were obtained. In FIG. 3 , the horizontal axis represents the ratio between the radius of curvature of the cross-sectional shape of each of the chamfers 17 and 17 and the outer diameter of the ball 5 held in the pocket 8, and the vertical axis represents the conventional shape as shown in FIG. Assuming that the noise level generated by the ball bearing constituted by using the retainer 6a is 0 dB, the difference in the noise level of the ball bearing when using the retainer in which the radius of curvature of each of the chamfers 17 and 17 is changed, Represents.
As is apparent from FIG. 3, when the radius of curvature of the cross-sectional shape of each of the chamfers 17 and 17 is set to 1% or more of the outer diameter of the ball 5 held in the pocket 8, the effect of temporarily reducing the cage sound can be obtained. can get. More preferably, if the radius of curvature of the cross-sectional shape of each of the chamfers 17 , 17 is set to 2 to 16% of the outer diameter of the ball 5, the effect of reducing the retainer sound becomes remarkable. More preferably, if the radius of curvature of the cross-sectional shape of each of the chamfers 17 , 17 is set to 4 to 15% of the outer diameter of the ball 5, the effect of reducing the retainer sound becomes more remarkable.

The difference in the radius of curvature affects not only the loudness of the retainer sound but also the workability. In other words, the regulation on the lower side leads to ease of mold processing, and the regulation on the upper side leads to reduction in machining cost by saving barrel machining time. Further, as a processing method for setting each of the chamfers 17 and 17 to a desired radius of curvature, any conventionally known processing method may be employed. However, in the case of a synthetic resin cage, it is preferable to perform processing with a mold from the viewpoint of processing cost. Also, in the case of a metal cage, it is preferable to perform processing by barrel processing also from the viewpoint of processing cost. When the radius of curvature of the cross-sectional shape of each of the chamfers 17 , 17 is larger than 20% of the outer diameter of the ball 5 held in the pocket 8, the holding force of the ball 5 is weakened, and the amount of movement of the cage is reduced. There is an adverse effect that the ball 5 becomes large or the ball 5 comes off from the pocket 8. For this reason, those having a radius of curvature exceeding 20% of the outer diameter of the ball 5 are unsuitable as a cage for enabling normal operation of the bearing, and the design of a rolling bearing incorporating such a cage is not suitable. Have difficulty. Therefore, the radius of curvature needs to be 20% or less of the outer diameter of the ball 5.

In each of the above-described embodiments, an example in which the present invention is applied to a ball bearing provided with a crown type cage has been described. However, the present invention is not limited to the ball bearing having the above crown type cage, as long as a rolling bearing provided with a cage, a ball bearing having a waveform retainer, it further be applied to a roller bearing it can. In addition, in order to minimize the amount of displacement of the cage with respect to the rolling element, the present invention has a structure in which the gap between the rolling surface and the inner surface of the pocket is made small, as well as a structure in which this gap has a normal size. But you can get the effect.

FIG. 2 is an enlarged cross-sectional view showing a first embodiment of the present invention, with a part of the retainer holding a ball. The figure similar to FIG . 1 which shows the same Example 2. FIG . 4 is a diagram illustrating a relationship between a radius of curvature of chamfering and a loudness of a cage sound generated during operation . FIG . 3 is a partially cut perspective view showing an example of a conventionally known ball bearing . The perspective view showing another example of the conventionally known cage . FIG. 5 is an enlarged cross-sectional view showing a state where the ball is held by the retainer shown in FIG. 4 . FIG. 6 is an enlarged cross-sectional view showing a state where a ball is held by the retainer shown in FIG. 5.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Inner ring track 2 Inner ring 3 Outer ring track 4 Outer ring 5 Ball 6, 6a Cage 7 Main part 8 Pocket 8a Depression 9 Element 10 Rivet 11 Holding concave surface 12 Elastic piece 13 Concave surface 14 Opening edge 15 Corner 16 Gap 17, 17a chamfer 18, 18a cage 19 cylindrical part 20 inclined surface

Claims (2)

  In a rolling bearing retainer, which is formed in an annular shape as a whole so as to hold a plurality of rolling elements so as to be able to roll freely and is provided with pockets at a plurality of positions in a circumferential direction, at least an opening peripheral portion of each of the pockets A cage for a rolling bearing, characterized in that a part of the roller is chamfered. The rolling according to claim 1, wherein the rolling element is a ball, the chamfer is a curved surface having a circular cross section, and a radius of curvature of the cross section of the chamfer is 1 to 20% of an outer diameter of the ball. Bearing cage.

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