JPH10281166A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing excellent in corrosion resistance and size stability and provide an increased life. SOLUTION: In a rolling bearing 1, track rings 2 and 3 are formed of non- crystalline synthetic resin and at least the surface part of a rolling body 4 is formed of a solid lubricant. As noted above, a material being excellent in corrosion resistance and wear resistance and also excellent in dimensional stability is selected as a material for the track rings 2 and 3. Further, lubricity of a contact portion with the track rings 2 and 3 is improved by the solid lubricant of the rolling body 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rolling bearing. In particular, the present invention relates to a rolling bearing used in an environment where corrosive substances exist, such as a transport system of a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Conventionally, in the above-mentioned applications, rolling bearings made of corrosion-resistant stainless steel are used.

[0003] Specifically, the applicant of the present invention has disclosed that
Made of S standard SUS440C, and retainer is JIS standard S
US304 is used as a base material and the surface is coated with a solid lubricant such as PTFE. For rolling elements, JIS standard SUS440C is used as a base material and PT
It is coated with a solid lubricant such as FE.

[0004]

By the way, in the above-mentioned metal material, an alkali solution (such as potassium hydroxide) used in a photoresist cleaning step in a semiconductor manufacturing apparatus is used.
On the other hand, in particular, it is inevitable that the inner and outer rings where the metal surface is exposed are eroded and worn.

In the above-described transfer system of a semiconductor manufacturing apparatus, since a heavy object is not transferred, the load-bearing performance does not need to be very high. However, if the life of the bearing is short, it is necessary to frequently replace the bearing. Each time the production line must be stopped, the operation rate of the line falls, and there is a problem that the production cost of the semiconductor increases.

On the other hand, it is conceivable to form the bearing ring with a synthetic resin material. Conventionally, as a material of a bearing ring, for example, polyacetal (PO) having excellent corrosion resistance and wear resistance has been used.
M) and other crystalline synthetic resins. However, these crystalline synthetic resins suffer from dimensional shrinkage (post-shrinkage) due to post-crystallization after molding, resulting in poor dimensional stability and short bearing life. Problem. Further, in the case of a resin having a low glass transition temperature such as polyacetal (POM), the working atmosphere is set to 40 as in the above-described photoresist cleaning step.
In a temperature range of up to 80 ° C., there is a problem that creep deformation occurs and the life of the bearing is shortened.

Accordingly, an object of the present invention is to provide a long-life rolling bearing having excellent corrosion resistance and dimensional stability.

[0008]

In the first rolling bearing of the present invention, the race is formed of an amorphous synthetic resin, and at least the surface of the rolling element is formed of a solid lubricant.

In the second rolling bearing according to the present invention, the race is formed of polyethersulfone (PES), and at least the surface of the rolling element is formed of a solid lubricant.

In the third rolling bearing of the present invention, the race is formed of polyethersulfone (PES), and at least the surface of the rolling element is formed of carbon material.

In a fourth rolling bearing of the present invention, the race is formed of polyethersulfone (PES), and the entire rolling element is formed of carbon material.

In short, according to the present invention, the material of the bearing ring does not need to be selected from materials that cause post-shrinkage, such as a conventional crystalline resin such as polyacetal (POM). Inexpensive materials with excellent dimensional stability are selected.

The amorphous synthetic resin used as the bearing ring does not deteriorate or change its dimensions over a long period of time even in an environment where corrosive substances such as alkaline solutions are present. In addition, since the solid lubricant on the surface of the rolling element improves the lubrication of the rolling contact portion or the sliding contact portion with the bearing ring, wear and damage are suppressed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on embodiments shown in FIGS.

1 and 2 relate to an embodiment of the present invention. FIG. 1 is a sectional view of an upper half of a rolling bearing, and FIG.
It is sectional drawing which shows the example of use of a rolling bearing. In the drawing, reference numeral 1 denotes the whole rolling bearing, 2 denotes an inner ring, 3 denotes an outer ring having a radially outward flange 3a, 4 denotes a plurality of spherical rolling elements, and 5 denotes a crown-shaped cage.

An application of the rolling bearing 1 is, for example, a transport system of a semiconductor manufacturing apparatus as shown in FIG. In the drawing, 10 is two parallel rail frames, 11
Is a shaft installed between the two rail frames 10,
Reference numeral 12 denotes a roller rotatably supported on the outer periphery of both ends of the shaft 11 via the rolling bearing 1. Reference numeral 13 denotes a spacer interposed between the inner ring 2 of the rolling bearing 1 and the rail frame 10. In this example, the rolling bearing 1 rotates the outer ring, the load acting on the rolling bearing 1 becomes a light load of, for example, 1 kgf or less, and the rotation speed becomes low, for example, about several tens of rpm.

The inner and outer rings 2, 3 and the retainer 5
Is an amorphous synthetic resin such as polyether sulfone (P
ES). Amorphous synthetic resin materials such as PES are resistant to corrosion against alkali solutions, for example, in immersion experiments in alkali solutions (potassium hydroxide solution or sodium hydroxide solution), there is no change in size and weight and no corrosion occurs. Excellent in nature.

The rolling element 4 may be formed entirely of a solid lubricant such as carbon. In this case, commercially available carbon spheres can be used. The rolling elements 4 may be made of, for example, a bearing steel or the like as a base material and the surface thereof is coated with carbon. In addition, a material coated with a soft metal such as gold or silver or a layered solid lubricant such as molybdenum disulfide may be used instead of carbon.

The physical properties of the PES are shown in Table 1 below. If the bearing is used under conditions of light load and low-speed rotation as in the transfer system of the semiconductor manufacturing equipment shown in FIG. 2,
There is no problem in strength. Also, the PES in the present embodiment
Is excellent in moldability such as low post-shrinkage and good dimensional stability, so that the inner and outer rings 2 and 3 and the retainer 5 can be manufactured by injection molding, which can contribute to a reduction in manufacturing cost. Further, since the glass transition temperature is as high as 225 ° C. and the elastic modulus is less dependent on the temperature, creep deformation does not occur even in an environment of 40 to 80 ° C. such as a photoresist cleaning step.

[0020]

[Table 1]

The inner and outer rings 2 and 3 are made of PES, and the rolling elements 4 are made of various materials as shown in Table 2. As shown in Table 2 below, it is found that the rolling element 4 has excellent corrosion resistance to an alkaline solution such as potassium hydroxide or sodium hydroxide, except when the rolling element 4 is made of a bearing steel such as SUJ2. In Table 2, ○ means no abnormality and △ means corrosion.

[0022]

[Table 2]

It should be noted that the present invention is not limited to only the above embodiment, and various applications and modifications are conceivable.

(1) In the above embodiment, the rolling bearing 1
As an example, a deep groove ball bearing having an outer ring 3 with a flange is illustrated, but the bearing type and bearing type are generally well-known, such as an angular ball bearing, a cylindrical roller bearing, a tapered roller bearing, a radial type, The present invention can be applied to various types such as a thrust type.

(2) The application of the rolling bearing of the present invention is not limited to the transfer system of the semiconductor manufacturing apparatus shown in FIG.
It can be used for bearing parts that have relatively light load and low speed rotation in various electric and mechanical products.

[0026]

According to the present invention, a material excellent in corrosion resistance, abrasion resistance, heat resistance and formability is selected as a material of a raceway, and a solid lubricant is applied to at least the surface of the rolling element. The lubrication of the contact area between the bearing ring and the retainer is enhanced by forming the groove to prevent wear and damage, thereby extending the life.

As described above, it is possible to provide a long-life synthetic resin rolling bearing that is inexpensive but avoids dimensional change and deterioration particularly in a corrosive environment and stabilizes rolling characteristics. As a result, in use,
It is not necessary to frequently replace the rolling bearing, which can contribute to a reduction in running costs.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing an example of use of the rolling bearing of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolling bearing 2 Inner ring 3 Outer ring 4 Rolling element 5 Cage

Claims (4)

[Claims] 1. A rolling bearing, wherein a race is formed of an amorphous synthetic resin, and at least a surface portion of a rolling element is formed of a solid lubricant. 2. The bearing ring is made of polyether sulfone (PE).
S), wherein at least a surface portion of the rolling element is formed of a solid lubricant. 3. The bearing ring is made of polyether sulfone (PE).
A rolling bearing formed of S), wherein at least a surface portion of the rolling element is formed of a carbon material. 4. The race is made of polyether sulfone (PE).
S), wherein the entire rolling element is formed of a carbon material.