JPH051718A - Solid lubrication rolling bearing - Google Patents

Abstract

PURPOSE:To secure the non-conductivity and durability of a solid lubrication film simultaneously. CONSTITUTION:PTEF conventionally used as a solid lubricant of a rolling bearing is a polymer whose average molecular weight is 2X10<5>-3X10<5>, but PTEF telomer (average molecular weight is 1X10<3>-3X10<3>) has an extremely smaller shearing strength and a softer characteristic in comparison with those of above polymer. Therefore, the abrasive powder of PTFE telomer is excellent in its rolling sticking ability and forms a lubrication film by entering even in the minute recessed parts of an opposite surface, and also shows an excellent lubrication performance owing to a small coefficient of friction because of a small shearing resistance. Since this solid lubrication rolling bearing has the lubrication films 1a, 2a, 3a formed by using above PTFE telomer, the lubrication films having a favorable lubrication performance are maintained over a long term due to the good rolling sticking ability and the low coefficient of friction of PTFE telomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid lubricating rolling bearing used in a vacuum of semiconductor manufacturing equipment or space equipment.

[0002]

2. Description of the Related Art Generally, a rolling bearing supplies a lubricant such as grease between the inner and outer races and the rolling elements and between the rolling elements and the cage to reduce rolling friction and sliding friction generated between them. It is designed to improve the durability of the bearing.

By the way, when the rolling bearing is used in a vacuum of space equipment or the like, a lubricant having a high vapor pressure such as grease evaporates into the atmosphere and cannot be used. Also,
When the rolling bearing is used in a highly vacuum-sealed vacuum such as a semiconductor manufacturing facility, the vapor of the lubricant becomes a pollution source of the environment, and therefore a fluid lubricant such as grease cannot be used. Therefore, the rolling bearing used in such an environment needs a solid lubricant having a low vapor pressure.

At present, as a solid lubricant for rolling bearings,
Layered substance-based lubricants such as molybdenum disulfide, soft metal-based lubricants such as gold, silver and lead, and polymer-based lubricants such as PTFE and polyimide are widely used. However, in recent years, in the field of semiconductor manufacturing, the line width of conductive patterns has become finer as the degree of integration of semiconductors has increased. Since there is a risk of short-circuiting, the conductive soft metal solid lubricant tends to be shunned.

[0005]

On the other hand, solid lubricants such as molybdenum disulfide and PTFE (polymer) do not have electrical conductivity, but they have poor transferability and low abrasion resistance, and therefore they are durable. Inferior to soft metals in terms of properties.

Therefore, an object of the present invention is to provide a solid lubricating rolling bearing particularly suitable for use in the field of semiconductor manufacturing, for which purpose the non-conductivity and durability of the solid lubricating coating are secured at the same time. This is a problem to be solved by the present invention.

[0007]

In the present invention, among the components that cause rolling friction or sliding friction of a rolling bearing, at least the surface of the rolling element has an average molecular weight of 1 × 10 ^{3 to} 3 ×.
A lubricating film made of 10 ³ polytetrafluoroethylene (PTFE telomer) was formed.

[0008]

The conventional PTFE used as a solid lubricant for rolling bearings has an average molecular weight of 2 × 10 ^{5 to} 3 × 10 ^5.
However, the PTFE telomer is the above-mentioned polymer.
Compared with, the shear strength is extremely small and it has the characteristics of being soft. Therefore, the abrasion powder of the PTFE telomer has excellent transferability, and even enters into the minute recesses on the mating surface to form a lubricating film. Further, since the shear resistance is small, the coefficient of friction is small and excellent lubricating performance is exhibited.

The solid lubricated rolling bearing of the present invention comprises the PT
A lubricant film is formed using FE telomer.
Due to the good transferability of the FE telomer and the low coefficient of friction, a lubricating film having good lubricating performance can be maintained for a long period of time.

[0010]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 shows a solid lubricating rolling bearing according to the present invention. This rolling bearing consists of inner ring 1, outer ring 2 and inner / outer ring 1
And a plurality of rolling elements 3 interposed between the two rolling elements 3 and cages 4 for holding the rolling elements 3 at equal intervals around the circumference. Lubrication films 1a, 2a, 3a of PTFE telomer are formed on the rolling surfaces of the inner and outer races 1, 2 and the surface of the rolling element 3. This lubricating film is a PTFE telomer (AR from Japan Acheson
C7) was sprayed and adhered to the film-forming surface from a position 25 cm apart, and the average film thickness in this case was 0.6 μm.

FIG. 2 shows the result of a life test conducted on the solid-lubricated rolling bearing having the above structure. For the life test, two test bearings supporting the shaft were used at room temperature and a vacuum degree of 10 ^-6 T.
orr, thrust load 1kgf, rotation speed 2500rpm
The test piece was rotated under the condition (1) and the life was defined as the time point when the total friction torque of the two test bearings reached 100 gcm. As shown in the figure, the solid-lubricated rolling bearing of this embodiment is made of PTFE.
The durability was four times or more that of a conventional solid lubrication rolling bearing having a polymer lubricating film formed thereon (life under the same conditions was 50 hours).

In this embodiment, the lubricating film is formed on the rolling surfaces of the inner and outer races and the surface of the rolling element, but the lubricating film may be formed at least on the surface of the rolling element. Further, the type of bearing is not limited to the one illustrated in FIG. 1 and can be widely applied to rolling bearings in general.

[0014]

As described above, the PTFE telomer is used.
By using as a solid lubricant, it is possible to form a solid lubricant film having non-conductivity and excellent in lubricity and durability. Therefore, according to the present invention, the durability of the solid lubrication rolling bearing is improved as compared with the one using the conventional PTFE solid lubricant, and it is possible to obtain the solid lubrication rolling bearing particularly suitable for use in the semiconductor manufacturing field. You can

[Brief description of drawings]

FIG. 1 is a sectional view showing a solid lubricating rolling bearing of the present invention.

FIG. 2 is a diagram showing a result of a life test.

[Explanation of symbols]

 1 Inner ring 1a Lubrication film 2 Outer ring 2a Lubrication film 3 Rolling element 3a Lubrication film

Claims (1)

Claim: What is claimed is: 1. A polytetrafluoroethylene (1) having an average molecular weight of 1 × 10 ^{3 to} 3 × 10 ³ (at least on the surface of the rolling element among the components that cause rolling friction or sliding friction of a rolling bearing) A solid lubrication rolling bearing characterized in that a lubricating film made of PTFE telomer) is formed.