JP2008281066A - Ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball bearing enhancing durability of a retainer by forming contact points on which surface of rolling elements contact, into a spherical curved surface avoiding pocket end edge parts, and by suppressing a contact load between a pocket and a rolling element. <P>SOLUTION: The ball bearing is provided with: an outer ring 12 having an outer ring raceway 11 in an inner circumferential surface; an inner ring 14 having an inner ring raceway 13 in an outer circumferential surface; a plurality of rolling elements 15 rollably arranged between the outer ring raceway 11 and the inner ring raceway 13; and the wave type press retainer 20 having the plurality of pockets 21 for rollably retaining these plurality of rolling elements 15. The pocket 21 of the wave type press retainer 20 has the pocket end edge parts 21c in an inner circumferential surface 21a and its both ends in a width direction, and the inner circumferential surface 21a of the pocket 21 is a spherical curved surface having a radius of curvature larger than that of the rolling element 15. Contact points P1, P2 contacting with a surface of the rolling element 15 are formed as spherical curved surfaces avoiding the pocket end edge parts 21c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a ball bearing used for a rotary bearing portion of various motors used for general industries.

  Ball bearings used in rotary bearings such as various motors used for general industries include an outer ring having an outer ring raceway on an inner peripheral surface, an inner ring having an inner ring raceway on an outer peripheral surface, the outer ring raceway and the inner ring raceway. And a plurality of rolling elements provided so as to be freely rotatable. The plurality of rolling elements are held in a rollable manner by a wave-type press holder having a plurality of pockets.

  That is, as shown in FIG. 5, in the ball bearing, the outer ring 12 having the outer ring raceway 11 on the inner peripheral surface and the inner ring 14 having the inner ring raceway 13 on the outer peripheral surface are arranged concentrically, and the outer ring raceway 11 and the inner ring raceway 13 are arranged. A plurality of rolling elements 15 are arranged so as to be capable of rolling. A plurality of pockets 17 are provided in a cage 16 having a corrugated press structure that holds the plurality of rolling elements 15 in a freely rollable manner.

  The cage 16 is formed by press-molding a metal plate material, and is configured by connecting a pair of ring members 18 with rivets 19. The plurality of pockets 17 are provided at equal intervals in the circumferential direction of the pair of ring members 18. Each pocket 17 is formed in a spherical concave surface 17a having an arc cross section having a slightly larger radius of curvature than the radius of curvature of the outer surface of the rolling element 15 so as to hold the spherical rolling element 15 so as to wrap the rolling element 15. keeping.

  That is, a pocket gap is formed between the spherical concave surface 17 a of the pocket 17 and the rolling element 15, and the surface of the rolling element 15 and the spherical concave surface 17 a pass through a lubricating film such as grease or oil as the rolling element 15 rotates. In contact with each other, the rolling elements 15 and the pockets 17 rotate with relative movement through the gap.

  In such a ball bearing cage, the inner surface of the pocket that holds the rolling element in a freely rolling manner is a spherical concave spherical surface having a radius of curvature larger than the radius of curvature of the rolling element, and the pocket extends from the edge of the spherical portion. It has also been known that it is configured by a cylindrical surface portion that reaches the opening edge of (see, for example, Patent Document 1).

  Further, in a similar ball bearing cage, the inner surface of the pocket for holding the rolling element in a freely rolling manner is formed by a spherical concave spherical surface having a radius of curvature larger than that of the rolling element, and a radius of curvature larger than the spherical surface. And a curved surface portion that is smoothly continuous from the edge of the spherical portion toward the opening edge of the pocket is known (see, for example, Patent Document 2).

  Further, in the same ball bearing cage, a concave surface having a center of curvature is formed at a position away from the center of the rolling element in the radial direction in the pocket that holds the rolling element in a freely rotatable manner. The distance between the center of curvature and the center of curvature is 0.2 to 2% of the diameter of the pitch circle (for example, see Patent Document 3).

  According to Patent Documents 1 to 3, a pocket gap is formed between the pocket surface of the cage and the rolling element, and the surface of the rolling element and the pocket surface form a lubricating film such as grease or oil as the rolling element rotates. Contact through. Therefore, sliding friction between the inner surface of the pocket and the rolling element can be reduced, and a ball bearing having low noise, low vibration, and durability can be provided.

As shown in FIGS. 6A to 6C, the design of the pocket portion for holding the rolling elements in the ball bearings as shown in Patent Documents 1 to 3 is based on the pocket depth H and the curvature radius R _1. Done. The interference between the rolling element 15 and the retainer 16 is determined according to the pocket shape of the retainer 16 by this design, and the retainer 16 rotates while being guided by the revolution of the rolling element 15. In general, if the pocket clearance of the cage 16 is too wide, the behavior of the cage 16 increases (causes a whirling), which leads to deterioration of vibration and noise. Conversely, if it is too narrow, the rolling element 15 and the cage The friction at the 16 contact portions increases, leading to an increase in torque.

Patent Document 3 eliminates vibration and noise problems related to cage movement, and changes the shape of the pocket by shifting the center of curvature of the concave surface forming the pocket shape of the cage from the pitch circle of the rolling element. There is something that let me. Further, as a technique for reducing torque, a method of using a lubricant having a lower viscosity and a method of increasing a pocket clearance are cited.
8 to 10 and 17 to 19 in JP-A-11-125256. 2 to 4 of JP-A-2003-239986 FIG. 1, FIG. 2, FIG. 10 of JP-A-2005-3105

  By the way, a load is usually applied to the ball bearing according to the application. That is, FIG. 7 depicts a state where a ball bearing in which the outer ring 12 is fixed and the inner ring 14 is loaded with a radial load and an axial load is misaligned. Misalignment occurs between the outer ring 12 and the inner ring 14, and the influence is also exerted on the cage through the rolling elements 15. When the misalignment is large, the cage 16 may be damaged.

  In this way, for example, under the usage conditions when the ball bearing is assembled in an inclined state, the behavior of the rolling element becomes unstable, and the position of the rolling element in the ball bearing becomes uneven. As a result, the cage is greatly deformed in the radial direction beyond the pocket gap, so that a large contact force acts on the interference portion between the rolling element and the cage, and the cage may be damaged.

  The present invention has been made paying attention to the above circumstances, and the object thereof is to make the inner peripheral surface of the pocket a spherical curved surface having a radius of curvature larger than the radius of curvature of the rolling element, and the surface of the rolling element comes into contact. An object of the present invention is to provide a ball bearing capable of improving the durability of the cage by making the contact point the spherical curved surface avoiding the pocket edge and suppressing the contact load between the pocket and the rolling element.

  In order to achieve the above object, according to the present invention, the first aspect of the present invention includes an outer ring having an outer ring raceway on an inner peripheral surface, an inner ring having an inner ring raceway on an outer peripheral surface, and an outer ring raceway between the outer ring raceway and the inner ring raceway. A ball bearing comprising a plurality of rolling elements provided movably and a wave press retainer having a plurality of pockets holding the plurality of rolling elements movably, wherein the wave press retainer comprises: The pocket has an inner peripheral surface and pocket edge portions at both ends in the width direction, and the inner peripheral surface of the pocket is a spherical curved surface having a radius of curvature larger than the radius of curvature of the rolling element. The contact point with which the surface contacts is the spherical curved surface avoiding the pocket edge.

Claim 2 is a pocket inner peripheral surface of the corrugated press retainer according to claim 1, wherein a contact point where the surface of the rolling element contacts is obtained by the following formulas (1) and (2): When the height from the bottom to the pocket edge is hi and the height from the pocket groove bottom to the contact point is hp, hp <hi.

However, H: Pocket depth R: The radius of curvature of the outer surface of the rolling element R1: The radius of curvature of the inner peripheral surface of the pocket W: The width of the pocket Claim 3 is the corrugated press cage of claim 1 or 2 It is the rolling element guide.

  According to the present invention, the inner peripheral surface of the pocket is a spherical curved surface having a radius of curvature larger than the radius of curvature of the rolling element, and the contact point where the surface of the rolling element contacts is the spherical curved surface avoiding the pocket edge. Thus, the contact load between the pocket and the rolling element can be suppressed, and the durability of the cage can be improved. Further, by suppressing the scraping of the lubricant at the contact portion by the pocket edge portion, it is possible to suppress an increase in friction due to the lack of the lubricant at this portion and to suppress the noise and vibration of the ball bearing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 4 show a first embodiment, and the same components as those in the prior art will be described with the same reference numerals. The basic structure of the ball bearing is the same as that of the prior art, and an outer ring 12 having an outer ring raceway 11 on an inner peripheral surface and an inner ring 14 having an inner ring raceway 13 on an outer peripheral surface are arranged concentrically. A plurality of rolling elements 15 are arranged so as to be capable of rolling.

A pocket 21 of the corrugated press retainer 20 of the present invention for holding the rolling element 15 so as to roll is configured as shown in FIGS. That is, in FIGS. 1A to 1C, when the width direction of the corrugated press cage 20 is displayed as the x direction, the circumferential direction is the y direction, and the radial direction is the z direction, the pocket 21 of the corrugated press cage 20 is displayed. The inner peripheral surface 21 a is formed in a spherical concave surface having a curvature radius R ₁ slightly larger than the curvature radius R of the outer surface of the rolling element 15.

  FIG. 2 shows that the rolling element 15 is displaced above the pocket 21 of the corrugated press cage 20 with the movement of the ball bearing, and the rolling element 15 contacts at the contact points P1 and P2 of the inner peripheral surface 21a of the pocket 21. It shows the situation. In the figure, when the height from the pocket groove bottom 21b to the pocket edge 21c is hi and the height from the pocket groove bottom 21b to the contact points P1, P2 is hp, hp <hi is set. The rolling element 15 is prevented from contacting (per corner) with the pocket edge 21c.

The hp and hi can be obtained by the following expressions (1) and (2).

Where H: pocket depth R: radius of curvature of the outer surface of the rolling element R1: radius of curvature of the inner peripheral surface of the pocket W: pocket width.

  Next, an analysis example using the present invention is shown. FIG. 3 is a front view of the ball bearing that is the subject of this analysis. Between the outer ring 12 and the inner ring 14, eight rolling elements 15 are arranged so as to be able to roll, and each rolling element 15 is corrugated. It is held in the pocket 21 of the press holder 20. Further, as shown in FIG. 7, the ball bearing is assumed to be loaded with a composite load consisting of radial and axial directions that cause misalignment. Furthermore, it is assumed that each pocket inner peripheral surface 21a has a radius of curvature that is completely R1 as an analysis condition. FIG. 4 shows the results of calculation of the load on the corrugated press cage of the ball bearing. In the conventional cage, the relationship between hp and hi becomes hp> hi, and the rolling element 15 is squared at the edge of the pocket 21. On the other hand, an analysis example in the case of hitting is indicated by a broken line curve, and as an example of the present invention, an analysis result in which hp = 0.98hi is indicated by a solid line curve.

  When the conventional relationship between hp and hi is hp> hi (dashed line curve) and when hp <hi (solid line curve) of the present invention, a large contact load is applied at the azimuth angles of 0 ° and 180 ° of the rolling element 15. However, when hp <hi, the rolling element 15 avoids the cornering of the pocket 21 against the edge 21c, so that the concentrated load near both the azimuth angles 0 ° and 180 ° of the rolling element 15 is reduced. It is suppressed and damage to the corrugated press cage 20 can be prevented. That is, as shown by the solid line curve, it can be seen that extreme contact force concentration has been eliminated. Therefore, a durable ball bearing can be provided.

  Furthermore, by making the contact points P1, P2 with which the surface of the rolling element 15 contacts the inner peripheral surface 21a avoiding the pocket edge 21c, the contact load between the pocket 21 and the rolling element 15 is suppressed, and the corrugated press The durability of the cage 20 can be improved. Further, by suppressing the scraping of the lubricant at the contact portion by the pocket edge 21c, it is possible to suppress an increase in friction due to the lack of the lubricant at this portion and to suppress the noise and vibration of the ball bearing.

  In the analysis example of FIG. 4, hp = 0.98hi, but by changing the parameters according to the size of the ball bearing and the intended use, and designing so that hp <hi, The concentrated load generated between the cage and the cage can be suppressed, and the corrugated press cage 20 can be prevented from being damaged.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine the component covering different embodiment suitably.

The pocket part of the corrugated press cage | basket of the ball bearing in the 1st Embodiment of this invention is shown, (a) is a side view, (b) is sectional drawing which follows the AA line, (c) is BB. Sectional drawing of only one side of a pocket along a line. The figure which shows the contact state of the pocket and rolling element of the corrugated press holder | retainer of the embodiment. The front view of the ball bearing of the embodiment. The graph which shows the numerical analysis result of the contact load of the corrugated press holder | retainer and rolling element in the 1st Embodiment of this invention, and the contact load of the conventional corrugated press retainer and a rolling element. The perspective view which a part of conventional ball bearing cut away. The pocket part of the cage | basket of the conventional ball bearing is shown, (a) is a side view, (b) is sectional drawing which follows CC line, (c) is sectional drawing along the DD line, and only one side of a pocket Figure. The longitudinal side view which shows a mode that the outer ring | wheel of the conventional ball bearing is fixed and the ball bearing by which the radial load and the axial load were loaded to the inner ring | wheel has produced misalignment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Outer ring raceway, 12 ... Outer ring, 13 ... Inner ring raceway, 14 ... Inner ring, 15 ... Rolling element, 20 ... Corrugated press cage, 21 ... Pocket, 21a ... Inner peripheral surface, 21c ... Pocket edge

Claims (3)

An outer ring having an outer ring raceway on an inner peripheral surface, an inner ring having an inner ring raceway on an outer peripheral surface, a plurality of rolling elements provided between the outer ring raceway and the inner ring raceway, and a plurality of rolling elements. In a ball bearing provided with a corrugated press cage having a plurality of pockets for holding a moving body in a freely rolling manner,
The pocket of the corrugated press cage has an inner peripheral surface and pocket edge portions at both ends in the width direction, and the inner peripheral surface of the pocket has a spherical curved surface having a radius of curvature larger than the radius of curvature of the rolling element. The ball bearing is characterized in that the contact point with which the surface of the rolling element contacts is the spherical curved surface avoiding the pocket edge. The contact point where the surface of the rolling element contacts the pocket inner peripheral surface of the corrugated press cage is obtained by the following formulas (1) and (2), and is a height from the pocket groove bottom to the pocket edge. 2. The ball bearing according to claim 1, wherein hp <hi, where hi is the height and hp is the height from the pocket groove bottom to the contact point.

Where H: pocket depth R: radius of curvature of the outer surface of the rolling element R1: radius of curvature of the inner peripheral surface of the pocket W: pocket width   The ball bearing according to claim 1, wherein the corrugated press cage is the rolling element guide.

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