JP2002098150A - Ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retainer which is capable of preventing the induction of retainer sound in the retainer used for a ball bearing. SOLUTION: In the ball bearing having a retainer 50 in which a pocket 1 accommodatingly holds a rolling element is formed in a plurality of positions in the circumferential direction, the ball bearing is characterized in that the pocket 1 has a recess 3 in the face on the axis direction side of the ball bearing and the rolling element is retained in the pocket 1 without having a contact with the inner surface of the recess 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball bearing having a retainer in which pockets for accommodating and holding rolling elements are formed at a plurality of circumferential positions.

[0002]

2. Description of the Related Art Rolling bearings are sometimes used to support rotating parts such as bearings of various rotating machines.
Among them, there are ball bearings using balls as rolling elements. And
As a cage for the ball bearing, a cage made of a resin material or metal, such as a crown shape, a corrugated shape, or a hollow shape is used. These retainers have a plurality of pockets. The inner walls of these pockets have substantially the same shape as the balls held and held by each pocket, and have a spherical shape whose radius of curvature is slightly larger than the radius of the balls. Then, by incorporating a plurality of balls into the pockets, the balls are equally held in the circumferential direction of the bearing.

FIG. 4 shows an example of a conventional crown-shaped retainer. The retainer 80 is made of a material in which glass fibers are mixed with nylon, or a resin material such as polyphenylene sulfide (PPS). The illustrated retainer 80
Are pockets 8 for rotatably storing balls (not shown in FIG. 4) at a plurality of locations in the circumferential direction of the annular main portion 86.
7 are provided. In the case of the retainer 80, each of the pockets 87 has an inner surface of a spherical surface 81. The radius of curvature of the spherical surface 81 is slightly larger than the radius of the held ball.

When assembling the ball bearings, each of the balls is pushed between the pair of elastic pieces while elastically expanding the gap between the tip edges of the pair of elastic pieces constituting each pocket 87. The cage 80 accommodates the balls in the respective pockets 87 in this manner, thereby holding each of the balls rotatably between the outer raceway and the inner raceway of the ball bearing.

When a ball bearing is used, the rolling of the ball causes
The outer ring and the inner ring of this ball bearing rotate freely relative to each other. At this time, the ball revolves around the inner ring while rotating. The retainer 87 rotates around the inner ring at the same speed as the revolution speed of the ball.

A lubricant such as grease or other lubricant is filled or continuously supplied between the inner wall of the outer ring and the outer peripheral surface of the inner ring so that relative rotation can be smoothly performed. This is because an oil film is formed between the ball of the ball bearing and the raceway surface of the inner and outer rings to avoid direct contact between the ball and the raceway surface of the inner and outer rings. This is to prevent vibration and obtain stable rotation for a long time. In some ball bearings, a sealing member such as a seal or a shield plate closes both openings of a space between the inner wall of the outer ring and the outer peripheral surface of the inner ring, and lubricant leaks from this space, or In some cases, foreign matter is prevented from entering this space.

[0007]

In the case of a ball bearing incorporating a retainer as described above, even if a required amount of lubricant is filled or supplied, vibration is induced in the retainer, whereby the ball bearing is thereby produced. In some cases, noise or vibration called cage sound may be generated. Such noise and vibration of the cage is caused by a large amount of movement of the cage with respect to the ball, or
Occurs based on the sliding friction between the ball and the cage.

In order to prevent the retainer sound, it is necessary to minimize the dimensional difference between the diameter of the ball and the diameter of the pocket of the retainer to reduce the amount of movement of the retainer relative to the ball.
If the gap between the ball and the inner wall of the pocket is small, there is a problem that the lubricant adhering to each ball is scraped off by the edge of each pocket and the lubricant becomes insufficient. When the lubricant is insufficient, a large frictional force acts between the ball and the pocket, and the stick-slip phenomenon based on the frictional force causes the cage to self-excitedly vibrate. As a result, the cage sound also occurs. . Also, if the amount of lubricant scraped off at the edge of the retainer is large, there is a shortage of lubricant entering between the ball and the raceway surface, and as a result, excessive friction or seizure occurs and rotation failure occurs. I will.

In view of the above, the present invention provides a ball bearing capable of suppressing the above-described cage sound and preventing excessive friction and seizure between the ball and the pocket. The purpose is to do.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ball bearing provided with a retainer in which pockets for accommodating and holding rolling elements are formed at a plurality of circumferential positions. Wherein the rolling element is held in the pocket without contacting the inner surface of the recess.

The pocket of the cage provided in the ball bearing according to the present invention has a shape which is not similar to the ball accommodated in the pocket due to the presence of the concave portion, and the rotation axis of the ball bearing formed in the pocket. It is possible to take a large amount of space in the direction as compared with the case of the conventional cage. By taking this space amount large, it becomes possible to contain more lubricant in this space,
Friction vibration of the contact portion between the retainer and the rolling element can be sufficiently suppressed. As a result, induction of the cage sound can be prevented.

This space is not formed in the running direction of the ball as the rolling element, and it is preferable that a large amount of lubricant is not taken in this direction. According to this, vibration does not occur due to an increase in the resistance of the lubricant to the rotation, and no cage noise is generated.

The pocket is preferably formed of a spherical portion for holding the ball and a concave portion. In particular, the concave portion is preferably a cylindrical surface portion or a conical surface portion. The center of the spherical portion may be coincident with the center of the cylindrical surface portion or the conical surface portion,
They do not have to match. However, the positional relationship between the spherical surface and the cylindrical surface or the conical surface must be such that the cylindrical surface or the conical surface is more concave than the spherical surface over the entire area. According to this configuration, the cylindrical surface portion or the conical surface portion does not contact the rolling element. Further, it is preferable that an edge is formed at the boundary between the spherical surface portion and the cylindrical surface portion or the conical surface portion. In the vicinity of the edge portion, it is preferable to make a relatively large step between the spherical surface portion and the cylindrical surface portion. By doing so, the gap between the inner wall of the pocket and the rolling element can be made relatively large in the vicinity of the edge portion,
It becomes easier to hold the lubricant in this gap.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described in detail.

In the present specification, the "circumferential section of the cage" refers to a cross section of the cage parallel to the circumferential surface of the ball bearing in which the cage is incorporated.
The vertical dashed line in FIG. 1 described below is a line parallel to the axis of the ball bearing, and the horizontal dashed line is a line parallel to the circumferential direction of the ball bearing. FIG. 2 is a perspective view showing a part of the retainer shown in FIG.

Hereinafter, the present embodiment will be described with reference to FIG. 1 and FIG. FIG. 1 shows a part of a circumferential cross section of a retainer 50 provided in an embodiment of the ball bearing of the present invention. FIG. 2 shows a part of the retainer 50 as a perspective view. The retainer 50 has a crown shape and includes a plurality of pockets 1 for retaining balls. However, only one pocket 1 is shown. An inner wall of the pocket 1 has a radius r1 from the center c1 of the spherical surface and a spherical portion 2 formed on the rotational direction (left-right direction in FIG. 1) of the ball bearing.
And a cylindrical surface portion 3 formed on the axial direction (vertical direction in FIG. 1) of the ball bearing. The cylindrical surface portion 3 is formed from the inner peripheral end 4 to the outer peripheral end 5 of the cage 50. Further, the cylindrical surface portion 3 has a radius r2 from the cylindrical center c2.

Attention is now directed to FIG. In the case of the present embodiment, the center c2 of the cylinder is displaced from the center c1 of the sphere by a distance d in the vertical chain line direction in FIG. However, cylindrical center c
2 may coincide with the sphere center c1, and in this case, the radius r1 of the spherical portion 2 is always different from the radius r2 of the cylindrical surface portion 3. However, when the cylindrical center c2 is separated from the spherical center c1 by a distance d upward in the vertical chain line direction in FIG. 1 as in the present embodiment, the ball held by the spherical portion 2 and the cylindrical surface portion 3 The distance to the bottom of the pocket 8
, The thickness h of the bottom portion 8 can be suppressed from being reduced, and the strength of the bottom portion 8 of the retainer 50 can be prevented from being reduced.

The spherical center c1 and the radius r of the spherical portion 2
1, and each of the cylindrical center c2 and the radius r2 of the cylindrical surface portion 3 need not be single, and at least one of the spherical portion 2 and the cylindrical surface portion 3 may be formed of a plurality of curved surfaces.

In the pocket 1, the cylindrical surface portion 3 is concave with respect to the spherical surface portion 2. Due to the presence of the concave portion, one of the ball bearings formed in the pocket 1 in the rotation axis direction (in FIG. The space to the side) is larger than in the case of the conventional cage. This relatively large space makes it possible to retain more lubricant in this space when balls are stored in the pocket 1. As a result, induction of the cage sound can be prevented.

In the retainer 50, the center angle of the arc forming the cylindrical surface portion 3 has an angle α. Assuming that the angle α is bisected around a line (vertical chain line in FIG. 1) parallel to the axis of the ball bearing into which the retainer 50 is incorporated, and the angles α1 and α2, respectively, in the present embodiment, the angle α1 And the angle α2 are equal. However, depending on the use conditions and use environment of the ball bearing, the angle α
1 and the angle α2 may be different.

Here, reference is made to FIG. FIG. 3 is an enlarged view near the edge 7 in FIG. As is particularly clear from FIG. 3, the end of the cylindrical surface 3 is formed at an angle β with respect to a line parallel to the axis of the ball bearing in which the cage 50 is incorporated. The angle β may be 0 degree, but if the angle β has a certain size (β> 0) as in the present embodiment, a space corresponding to the angle β can be provided, and the lubricant is filled in this space. Can be held.

The positional relationship between the spherical surface portion 2 and the cylindrical surface portion 3 is such that the cylindrical surface portion 3 is more concave than the spherical surface portion 2 over the entire area. In this embodiment, the recess is located on the bottom side of the pocket. According to this configuration, the cylindrical surface portion 3 does not come into contact with the ball. In the vicinity of the edge portion 7, it is preferable that a step between the spherical surface portion 2 and the cylindrical surface portion 3 is relatively large. By doing so, the gap between the ball and the inner wall of the pocket 1 can be made relatively large near the edge portion 7, so that a large amount of lubricant can be held in this gap.

The pocket 8 of the conventional retainer 80 shown in FIG.
In 7, when the ball is in contact with the pocket bottom,
The rotation of the cage 80 becomes unstable with respect to the rotation of the bearing, that is, the revolution of the ball. This is because the bottom surface of the pocket and the ball are in one-point contact, and there is nothing to restrict the relative movement of the ball and the pocket 87 in the circumferential direction. This state corresponds to, for example, a case where the bearing is installed and operated in such a manner that the opening of the crown-shaped cage faces downward. In such a case,
Since the rotation of the cage becomes unstable in the circumferential direction as described above with respect to the revolution of the ball, a cage sound is induced.

On the other hand, according to the above embodiment, since the two edges 7 are arranged so as to face each other in the circumferential direction, the retainer 50 moves in any of the axial directions with respect to the ball. However, a state in which the cage is supported by one of the edges 7 is obtained, and stable cage rotation is obtained, and induction of cage sound is suppressed. Such an operation and effect can be obtained in the same manner for the machined cage and the corrugated press cage.

The embodiments described above are examples for carrying out the present invention, and the present invention can be carried out without being limited to these embodiments. For example, the recess formed in the pocket need not be a cylindrical surface, but may be a conical surface, for example. Further, the retainer does not need to be crown-shaped, but may be a waveform or a timer having a hollow shape. For example, in the case of a corrugated cage or an extruded cage, a recess is formed on at least one surface, preferably both surfaces, of the inner wall of the pocket in the axial direction of the cage.

[0026]

As described above, in the ball bearing according to the present invention, the pocket for holding the rolling element has a recess on the axial side of the ball bearing, and the rolling element contacts the inner surface of the recess. Because it is characterized by being held in the pocket without
It is possible to prevent induction of the cage sound.

[Brief description of the drawings]

FIG. 1 shows an axial section of a cage according to an embodiment of the present invention.

FIG. 2 shows a perspective view of a cage according to the embodiment of the present invention.

FIG. 3 shows a partially enlarged view of the retainer shown in FIG.

FIG. 4 is a perspective view of a retainer provided in a conventional ball bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pocket 2 Spherical part 3 Cylindrical surface part 4 Inner peripheral end of retainer 5 Outer peripheral end of retainer 7 Edge c1 Center of spherical part c2 Center of cylindrical surface part r1 Radius of spherical part r2 Radius of spherical part 50 Cage

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nobuta, Nobori 1-5-50 Kugenuma Shinmei, Fujisawa-shi, Kanagawa F-term in NSK Ltd. (reference) 3J101 AA02 AA32 AA42 AA62 BA25 BA44 BA50 CA11 EA36 EA63 FA01 FA33

Claims (1)

[Claims] 1. A ball bearing provided with a retainer in which pockets for accommodating and holding rolling elements are formed at a plurality of positions in a circumferential direction, wherein the pocket has a concave portion on a surface of the ball bearing on an axial direction side; A ball bearing wherein the moving body is held in the pocket without contacting the inner surface of the recess.