JP2006017241A - Ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball bearing capable of smoothly maintaining rotation by reducing the rise of a rotating torque when balls are clogged even when the number of separators disposed in a rolling element raceway is large. <P>SOLUTION: Either of a spherical separator 4 and a columnar separator 14 having a diameter smaller than that of balls 3 is disposed in the same rolling element raceway for the balls 3 carrying the load of the bearing. By this, the bearing torque when the balls are clogged can be reduced more than that in a conventional bearing in which only the columnar separator 14 is disposed. As a result, even the number of the separators disposed in the raceway is large, the rise of the torque in rotating can be suppressed to maintain the smooth rotation of the ball bearing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ball bearing including a plurality of separators between balls arranged in a rolling element raceway.

  For equipment used in environments where it is difficult to use grease, such as semiconductor manufacturing equipment, a cylindrical separator (also called a spacer or spacer) made of a self-lubricating material containing a solid lubricant is used as a ball. Ball bearings arranged between each other are used (see Patent Documents 1 and 2).

  FIG. 4 is a perspective view of a ball bearing using a conventional cylindrical separator, with a part broken away to show the structure of the ball bearing. FIG. 5 shows the separator used in this ball bearing in the end face direction ( It is the figure seen from a) and the longitudinal direction (b).

  The ball bearing includes an outer ring 11 having an outer ring side raceway groove 11a on an inner peripheral surface, an inner ring 12 having an inner ring side raceway groove 12a on an outer peripheral surface, and a plurality of rolling element raceways formed by these raceway grooves. The ball 13 and a plurality of separators 14 fitted in the same rolling element track as the ball 13 and disposed between the balls 13 are mainly configured.

  The separator 14 has a substantially cylindrical shape having an outer diameter slightly smaller than the diameter of the ball 13, and is formed by sintering using, for example, metallic tungsten mixed with tungsten disulfide. In addition, when this separator 14 is seen from the axial center direction (longitudinal direction of a separator) of a ball bearing, the shape of the projection surface has comprised the rectangle like FIG.5 (b).

JP-A-9-144760 Japanese Patent Laid-Open No. 10-47359

  By the way, in the ball bearing using a plurality of columnar separators in the rolling element raceway as described above, the bearing torque may increase when the bearing rotates.

  As shown in the schematic diagram of FIG. 6, this phenomenon is because the cylindrical separator 14 is inclined in the circumferential direction due to clogging caused by the advance and delay of the ball 13, and the corner portion of the separator 14 is the track of the inner and outer rings. It is considered that it is generated by being strongly pressed against the grooves 11a and 12a (so-called wedge effect).

  In addition, this problem is likely to occur in a ball bearing having a large number of balls and separators, and the influence of the ball bearing having a thinner bearing ring is greater.

  The present invention has been made in view of such circumstances, and even when the number of separators arranged on the rolling element track is large, the increase in rotational torque at the time of occurrence of clogging is small, and smooth rotation is maintained. It aims at providing the ball bearing which can be used.

  In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a roller formed between an outer ring side raceway groove provided on an outer ring inner circumferential surface and an inner ring side raceway groove provided on an inner ring outer circumferential surface. A ball bearing comprising a ball and a separator in a moving body track, wherein one or a plurality of the balls are arranged with either a spherical separator or a cylindrical separator having a smaller diameter than the ball. And

  The present invention intends to achieve the intended purpose by arranging two types of separators having different shapes between balls arranged in a rolling element track.

  That is, according to the first aspect of the present invention, by arranging either a spherical separator or a cylindrical separator having a smaller diameter than the ball in the same rolling element raceway as the ball, the rotational torque at the time of occurrence of clogging is obtained. An increase can be prevented. In other words, by replacing a part of the cylindrical separator that becomes a wedge between the inner and outer rings when receiving a force from the load balls adjacent to both sides in the circumferential direction, the conventional cylindrical separator is replaced with an unloaded spherical separator. It is possible to reduce the bearing torque when ball clogging occurs, compared to a ball bearing in which only the ball is disposed. Therefore, in the ball bearing of the present invention, even when ball clogging occurs, an increase in torque during rotation can be suppressed and smooth rotation can be maintained.

  In addition, the ball bearing of this invention can employ | adopt suitably the structure by which the said spherical separator and the said cylindrical separator are alternately arrange | positioned for every other said ball | bowl. (Claim 2)

  In order to avoid contact between the load balls, it is desirable to dispose these separators all between the balls, and it is preferable that these separators are disposed so that the same shape is not biased in the circumferential direction. . With this configuration, the ball bearing of the present invention can maintain a smooth rotation with a low torque over a long period of time.

  As described above, according to the ball bearing of the present invention, even when the number of separators arranged in the raceway is large, an increase in rotational torque when a ball clogging occurs can be suppressed.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view in the axial parallel direction showing the structure of the ball bearing in the embodiment of the present invention, and FIG. 2 is an axial cross-sectional view of this ball bearing.

  The basic structure of the ball bearing in this embodiment is the same as that of a conventional ball bearing, and an outer ring 1 having an outer ring side raceway groove 1a on an inner peripheral surface, and an inner ring 2 having an inner ring side raceway groove 2a on an outer peripheral surface. A plurality of balls 3 arranged on the rolling element raceway formed by these raceway grooves are mainly configured.

  A feature of the ball bearing in the present embodiment is that spherical separators 4 and cylindrical separators 14 each having a smaller diameter than the balls 3 are alternately arranged in the circumferential direction between the balls 3 fitted in the rolling element raceways. Is a point. The cylindrical separator 14 in this example is formed by sintering metallic tungsten mixed with tungsten disulfide, as in the conventional example, and the spherical separator 4 is formed using stainless steel.

  FIG. 3 is a schematic diagram for explaining the state of the ball 3 and the separators 4 and 14 when ball clogging occurs during rotation in the ball bearing configured as described above. In the drawing, the diameter difference between the ball 3 and the spherical separator 4 is exaggerated for easy identification.

  As shown in this figure, the ball bearing according to the present embodiment is configured such that the spherical separators 4 that do not become wedges between the inner and outer rings are alternately arranged with the cylindrical separators 14 in the circumferential direction. , 3, the increase in rotational torque is suppressed as compared with the conventional ball bearing using only the cylindrical separator 14 in the conventional example (FIG. 6).

  Therefore, the ball bearing in the present embodiment does not increase in torque even when ball clogging occurs due to rotation of the bearing, and can maintain smooth rotation.

  In addition, the detailed shape of the cylindrical separator 14 is not limited to the example in this embodiment, For example, you may perform a chamfering process or R process to the edge part (corner part) of both end surfaces. In the present invention, the material of the cylindrical separator 14 and the spherical separator 4 is not particularly limited.

  Furthermore, in the present embodiment, an example in which these separators are arranged every other ball 3 is shown, but the arrangement of the separators in the ball bearing of the present invention is not limited to the configuration in this example. The separators may be arranged at intervals of a plurality of balls. Moreover, the spherical separator 4 and the cylindrical separator 14 do not necessarily have to be alternately arranged in the bearing circumferential direction.

It is sectional drawing of the axis-parallel direction which shows the structure of the ball bearing in embodiment of this invention. It is an axial sectional view of the ball bearing of FIG. In the ball bearing of this invention, it is a schematic diagram explaining the state of a ball | bowl and a separator when a ball clogging generate | occur | produces during rotation. It is a perspective view which shows the structure of the ball bearing using the conventional cylindrical separator. It is the figure (a) which looked at the separator used for the conventional ball bearing from the end surface direction, and the figure (b) which looked from the longitudinal direction. In a conventional ball bearing, it is a mimetic diagram explaining a state of a ball and a separator at the time of ball clogging generating during rotation.

Explanation of symbols

1,11 Outer ring 1a, 11a Outer ring side raceway groove 2,12 Inner ring 2a, 12a Inner ring side raceway groove 3,13 Ball 4 Spherical separator 14 Cylindrical separator 5,15 Shield

Claims (2)

  A ball bearing comprising a ball and a separator in a rolling element raceway formed between an outer ring side raceway groove provided on an outer ring inner circumferential surface and an inner ring side raceway groove provided on an inner ring outer circumference surface, A ball bearing, wherein one or a plurality of balls is provided with either a spherical separator or a cylindrical separator having a smaller diameter than the balls. The ball bearing according to claim 1, wherein the spherical separator and the cylindrical separator are alternately arranged in the circumferential direction every other ball.

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