JP2527053Y2 - Rolling bearing for vacuum - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing for vacuum used as a bearing for an X-ray tube or the like.

[0002]

2. Description of the Related Art Conventionally, as a rolling bearing for vacuum, FIG.
As shown in (b), inner and outer rings 1 made of stainless steel,
The track surface of No. 2 is super-finished, and the surface of the ball 3 is provided with a silver ion plating (Ag-Ip) film 5.

[0003]

However, in the above-described conventional rolling bearing for vacuum, although the raceway surfaces of the inner and outer rings 1 and 2 are simply super-finished, the hardness of stainless steel is relatively low. For this reason, the raceway surface has a certain degree of roughness. Therefore, under use conditions of high temperature and high speed, irregularities on the raceway surfaces of the inner and outer races 1 and 2 cause the Ag-Ip film 5 of the ball 3 to be shaved, resulting in a large friction torque and a short life.

Accordingly, an object of the present invention is to provide a vacuum rolling bearing having a small friction torque and a long service life even under a use condition of high temperature and high speed.

[0005]

In order to achieve the above object, the vacuum rolling bearing of the present invention is provided with a hard film which is harder than the inner ring and the outer ring and has a high working accuracy on the raceways of the inner ring and the outer ring. A soft metal film having lubricity is provided on the rolling surface of the rolling element, and the hard film is subjected to finish processing so that the surface roughness of the hard film is smaller than the surface roughness of the soft metal film. And

[0006]

Since the hard film is harder than the inner and outer rings, the processing accuracy of the surface is improved, and the surface roughness of the hard film is smaller than the surface roughness of the inner and outer rings themselves. Therefore, the method of shaving the soft metal film on the surface of the rolling element by the hard film is reduced. As a result, the friction torque is reduced, the time for lubrication by the soft metal film is extended, and the life is extended.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. In FIG. 1, reference numerals 1 and 2 denote an inner ring and an outer ring, which are made of high-speed tool steel (SKH) or stainless steel (SH).
US). 3 is a ball made of stainless steel. The raceway surfaces of the inner and outer rings 1 and 2 are coated with titanium nitride (TiN) films 6 and 7 as hard films, which are harder than those, and the surfaces of the TiN films 6 and 7 are lap-finished. The roughness was reduced and cured. As a result, the surface roughness Rz of the TiN films 6 and 7 is set to 0.1.
Below 1 μm, the average was about 0.05 μm and its hardness was 2000-3000 Hv.

On the other hand, on the surface of the ball 3, an Ag-Ip film 5 as a soft metal film having lubricity was applied. The surface roughness of the Ag-Ip film 5 is larger than the surface roughness of the TiN films 6 and 7. However, the surface roughness of the Ag-Ip film 5 was about 0.05 μm because the surface roughness of the TiN films 6 and 7 during operation.

According to the above configuration, since the TiN films 6 and 7 are harder than the inner and outer rings 1 and 2, the processing accuracy when lapping the surface thereof is improved, and as shown in FIG. The surface roughness of the TiN films 6, 7 becomes smaller than the surface roughness of the TiN films 1, 2 themselves. Therefore, the method of shaving the Ag-Ip film 5 on the surface of the ball 3 by the TiN films 6 and 7 is reduced.
As a result, the friction torque decreases, the lubrication time by the Ag-Ip film 5 increases, and the life increases.

When the above bearing is used as a support bearing for an X-ray tube, the inner ring 1 and the outer ring 2 are electrically connected to each other by a conductive brush (not shown) to prevent static electricity.

In the above embodiment, the TiN films 6 and 7 are used as the hard films. However, a titanium carbide (TiC) film may be used, and any film may be used as long as it is harder than the inner and outer rings themselves. Further, a roller may be used as a rolling element, and its rolling surface may be coated with a soft metal film such as an Ag-Ip film.

[0012]

[Effects of the Invention] As is clear from the above description, in the rolling bearing for vacuum of the present invention, the rolling surface of the rolling element is coated with a soft metal film having lubricity, and the raceway surfaces of the inner and outer rings are made harder than those. The hard film is coated with a hard film that can easily be processed with high precision, and this hard film is subjected to finish processing so that the surface roughness of this hard film is smaller than the surface roughness of the soft metal film. In addition, the method of shaving the hard metal film against the soft metal film is reduced, the friction torque is reduced, and the lubrication time is increased, and the life is extended.

[0013]

[Brief description of the drawings]

FIG. 1 is a sectional view of a vacuum rolling bearing according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the present invention and a conventional example.

[Explanation of symbols]

1 ... inner ring, 2 ... outer ring, 3 ... ball, 6, 7 ... TiN
Film, 5 ... Ag-Ip film.

Claims (1)

(57) [Scope of request for utility model registration] 1. A hard film which is harder than the inner ring and the outer ring and has high processing accuracy is provided on the raceway surfaces of the inner ring and the outer ring, and a soft metal film having lubricity is provided on the rolling surface of the rolling element. A rolling bearing for vacuum, characterized in that the film is subjected to finish processing so that the surface roughness of the hard film is smaller than the surface roughness of the soft metal film.