JPH0341218A - Lubricating device for bearing in vacuum - Google Patents

Abstract

PURPOSE:To prolong the service life of a bearing by constructing a part of the bearing to be used in vacuum of a soft metal or solid lubricant with which lubricating effect can be obtained, applying a potential difference between the part of the bearing and a sliding member with both of them insulated from the other constructional members to produce electric discharge, and replenishing thin film with lubricating effect occasionally to sliding portions. CONSTITUTION:Seal plates 1' are constructed of a soft metal or a solid lubricant 1 with which lubricating effect can be obtained. A potential difference is given by a power supply 8 between the seal plates 1' and the bearing outer ring 4 which is the other constructional member of a bearing. By this, since the ambience is in vacuum, electric discharge is produced between both of the seal plates 1' and the outer ring 4, and the lubricant 1 is ionized by means of electric discharge to form a thin film on the outer ring 4. Accordingly, a thin film with lubricating property is formed and replenished during operation by discharging electricity occasionally. Thus, the service life of the bearing can be extended remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lubricating device for improving the life of bearings used in vacuum, such as semiconductor manufacturing equipment and space-related equipment.

[Conventional technology]

Lubrication in a vacuum, where lubricating oil or grease cannot be used, has traditionally been achieved by coating sliding parts with a thin film of soft metal or solid lubricant. Examples of this are also described in bearing manufacturer catalogs such as NSK Technical Journal, technical documents, etc., and it is an in-depth knowledge.

In addition, recently in ball bearings, Japanese Patent Application Laid-Open No. 62-27082
In addition to coating the balls and the inner and outer shafts with films as described in No. 6, solid lubricants may be provided on the cage, and multiple films may be applied as described in JP-A-62-258224. Efforts have been made to extend the lifespan by applying multiple layers of coating.

[Problem to be solved by the invention]

However, unlike the above-mentioned conventional technology, it is not possible to use moisture using a coated thin film. i') Bearings used in equipment reach their lifespan limit when the membrane wears out and loses its lubricating effect. Recently, improvements have been made to extend the life of the film, such as changing the material and coating method, but the coated film is not as good as Iy! It will eventually disappear due to rubbing.

Therefore, a system including a bearing using a lubricating device according to the above-mentioned prior art has the trouble of having to stop the device every time due to the lifespan of the membrane, requiring maintenance such as field and replacement.

Furthermore, in space, etc., where maintenance such as parts replacement is difficult, systems that include bearings that use the conventional lubricating device described above will become unusable due to the life of the bearings, and the entire system will have to be abandoned. There was a serious problem.

As mentioned above, the purpose of this research is to provide a lubricating device that can maintain good lubrication effects over a long period of time for bearings used in a vacuum where lubricating oil, grease, etc. cannot be used. be.

[Means to solve the problem]

As a distant relative of the above purpose, one of the bearings used in vacuum
The part or part of the surrounding part is made of soft metal, solid lubricant, or polymeric composite material that can provide lubrication, is insulated from other bearing components, and has a sliding part. It has a structure that can apply a potential difference between it and the member, and is further equipped with means for changing the atmospheric pressure, such as a gas introduction system.

[Effect]

By applying a potential difference between a member that has a lubricating effect, such as a soft metal, solid lubricant, or polymeric composite material, which is placed in or around a part of the bearing, and a member that has a sliding part, the difference between the two can be reduced. A discharge occurs between them. Thereby, the sliding portion can be coated with a thin film having a lubricating effect. That is, it becomes possible to supply and form the film.

Therefore, 11! ! By applying a potential difference intermittently while the device is in operation or when it is stopped, and replenishing the membrane at any time, the lifespan can be significantly improved.

If the atmospheric pressure is too low to cause discharge, it is sufficient to introduce gas from the provided gas introduction system and change the pressure to a level at which discharge can occur.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a first embodiment of the lubricating device of the present invention. This example is an example of a ball bearing used in a vacuum, and the shield plate, which is one of the components of the ball bearing, is made of lubricating soft metal, solid lubricant, polymer composite material, etc. This is a dispute using . From now on, these lubricating 1
Deceptive metal.

Solid lubricant materials, polymer composite materials, etc. are simply referred to as lubricants.

In FIG. 1, 1 is a lubricant, 2 is an insulator that insulates between the lubricant 1 and other bearing members, and 3, 4 and 5 are balls, an outer ring, and an inner ring of a ball bearing, respectively. Further, 6 is a rotating shaft, 7 is a casing that fixes the bearing, and 7 and 8 are power sources that provide a potential difference between the lubricant 1 and the outer shaft 11 of the bearing. In the bearing configured in this way, when a potential difference is applied between the lubricant 1 and the outside @ 4 by the power source 8, a discharge occurs between the two because the atmosphere is a vacuum, and the lubricant is ionized by the discharge. Then, it is transferred to the outer ring to form a thin film. By performing this operation whenever necessary during operation of the equipment, it is possible to replenish and form a lubricating thin film, thereby dramatically extending the life of the bearing.

In this example, since the lubricant 1 and the plate 1' on the opposing surface are seed materials, it is possible to prevent contamination of the surroundings. In this example, if the outer ring 4 and balls 3. Domestic import 5 becomes 4
If it is an m-body and is electrically conductive, a d-film can also be formed on the inner and outer axes and on the balls.

FIG. 2 shows another embodiment, in which lubricant 1 is used in a part of the peripheral members of the ball bearing. In this example as well, a lubricating thin film can be formed by the same operation as in Example No. ↓. Also in this case, the shield plates 9,9' prevent contamination of the surroundings.

FIG. 3 shows still another embodiment of the present invention,
The embodiment shown in FIGS. 1 and 2 is further equipped with a gas supply device.

In cases where the atmosphere is a high vacuum such as in outer space and no discharge occurs, gas is introduced from the gas supply device 10 to a pressure that allows discharge only when it is desired to replenish and form a thin film on the bearing. A potential difference is applied to cause a discharge. In this case, the most suitable gas may be used among various gases such as argon, oxygen, and nitrogen according to the lubricant 1 to be used.

The embodiment shown in FIG. 4 shows an embodiment in which a drop bearing is used as the bearing. In the case of sliding bearings as well, the thin film can be replenished as needed by operations similar to those in the embodiments shown in FIGS. In the case of a sliding bearing, since the sliding bearing 11 and the shaft 6, that is, the mating surface that is received by the bearing, slide directly, as shown in this example, the shirt 1-6, that is, the mating surface that is received by the bearing, slides directly. and as a conductor,
Electrodeposition is applied between the lubricant 1 and the shaft 6 to form a film.
Can be replenished. In this example, a slip ring is used as an example of a means for energizing the shaft 6.

The example shown in FIG. 5 is an example in which this embodiment is applied to a direct-acting ball bearing. FIG. 6 shows an example of application to a linearly moving verri bearing. In both the embodiments shown in Figs. 5 and 6, by performing the same operations as in the embodiments shown in Figs. 1 to 4, it is possible to replenish and form a thin film of lubricant 1 on the sliding surface. It becomes possible to dramatically extend the lifespan of

〔Effect of the invention〕

According to the present invention, lubricant can be supplied and formed as necessary to the bearings of equipment operated in a vacuum while the equipment is operating, so the equipment can be operated stably for a long period of time and has a long lifespan. can also be increased dramatically.

[Brief explanation of drawings]

FIG. 1 to FIG. 6 are diagrams each showing an embodiment of the present invention. 1... Lubricant, 1' - Seal plate, 2 - Insulator, 3°4.5... Ball, outer ring and inner ring, 6... Shaft, 7
・Casing, 8・Current, 1o...Gas supply device, 1
1... Sliding bearing, 12 ・Direct acting ball bearing, 1
3...Slip ring.

Claims (1)

[Claims] 1. In a bearing used in a vacuum, at least one of the members having a sliding part is made of a conductor, and some of the other members of the bearing or surrounding members are made of a conductor. a part of which is made of a soft metal, the member having the sliding part is insulated from the soft metal, and further a current is connected between the member having the sliding part and the soft metal, A lubricating device for a vacuum bearing, characterized in that a soft metal film is supplied and formed on a sliding part of a member that requires a sliding part by applying a potential difference to the space between them and causing an electric discharge. 2. The lubricating device for vacuum bearings according to claim 1, wherein the lubricating device replenishes and forms the soft metal film by causing an electric discharge intermittently during operation or when the device is stopped. 3. A method for lubricating a vacuum bearing according to claim 1 or 2, characterized in that a shield plate is provided to prevent soft metal from adhering to and contaminating members other than the bearing due to electrical discharge. 4. The lubricating device for a vacuum bearing according to any one of claims 1 to 3, further comprising means for changing the atmospheric pressure when applying a potential difference to cause discharge. 5. The vacuum bearing lubrication device according to any one of claims 1 to 4, wherein the bearing is a ball bearing. 6. A method for lubricating a vacuum bearing according to any one of claims 1 to 6, wherein the bearing is a sliding bearing. 7. In the lubricating device according to claim 6, the mating surface on which the bearing is received is used as a conductor to insulate between the soft metal and a means for supplying current between the power source and the mating surface. A lubricating device for a vacuum bearing, characterized in that a potential difference is applied to the space between the bearings and a soft metal film is replenished and formed on the opposing surface. 8. A lubricating device for a vacuum bearing according to any one of claims 1 to 7, characterized in that a solid lubricant is used in place of the soft metal. 9. The lubricating device for a vacuum bearing according to any one of claims 1 to 8, characterized in that a polymer composite material is used in place of the soft metal.