JP2723980B2 - Lubrication device for vacuum bearings - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lubrication device for improving the life of a bearing used in a vacuum, such as a semiconductor manufacturing device and space-related equipment.

[Conventional technology]

Conventionally, lubrication in a vacuum in which lubricating oil or grease cannot be used has been performed by coating a thin portion of a soft metal or a solid lubricant on a sliding portion. Examples are described in bearing manufacturer catalogs such as NSK Technical Journal, technical samples, and the like, and are common knowledge.

In recent ball bearings, as described in Japanese Patent Application Laid-Open No. 62-270826, in addition to coating the film on the balls and inner and outer rings, a solid lubricant is provided on the cage,
As described in Japanese Patent No. 258224, various measures have been taken to extend the service life, for example, by coating a plurality of films one upon another.

[Problems to be solved by the invention]

However, the bearing used in a lubricating device using a coated thin film as in the above-mentioned prior art has its life limited when the film is worn out and loses the lubricating action. In recent years, efforts have been made to extend the service life of the film, for example, materials, coating methods, and the like. However, the coated film is eventually lost due to friction.

Therefore, the system including the bearing using the lubricating device according to the above prior art has the trouble that the device is stopped one by one due to the life of the film and maintenance such as disassembly and replacement is required.

Further, in a space or the like where maintenance such as replacement of parts is difficult, a system including a bearing using the above-described lubricating device according to the above-mentioned prior art becomes unusable due to the life of the bearing, and the entire system must be abandoned There was a serious problem.

The purpose of this research is to provide a lubricating device that can maintain the lubricating effect of a bearing used in a vacuum where lubricating oil and grease cannot be used for a long period of time, as described above. is there.

[Means for solving the agenda]

In order to achieve the above object, one part of a bearing used in a vacuum or a part of a peripheral part is made of a soft metal, a solid lubricant, or a polymer composite material capable of obtaining a lubricating action, It has a structure in which a potential difference can be applied between a member having a sliding portion and insulation from other members constituting the bearing, and further includes means for changing the atmospheric pressure such as a gas introduction system.

[Action]

By applying a potential difference between a member such as a soft metal, a solid lubricant, or a polymer-based composite material having lubricating action disposed on one portion or a peripheral portion of the bearing, and a member having a sliding portion, Discharge occurs between the two. Thereby, a thin film having a lubricating action can be coated on the sliding portion. That is, it is possible to supply and form a film.

Accordingly, by intermittently applying a potential difference during the operation of the device or when the operation is stopped, and replenishing the membrane as needed, the life can be dramatically improved.

In the case where the atmospheric pressure is too low and discharge does not occur, a gas may be introduced from the provided gas introduction system to change the pressure to a pressure at which discharge can be generated.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the lubricating device of the present invention. This embodiment is an example of a ball bearing used in a vacuum as a bearing. One of the components of the ball bearing is a lubricating soft metal, a solid lubricant, a polymer composite, etc. Is used. Hereinafter, these lubricating soft metals, solid lubricating members, polymer composites, and the like are simply referred to as circulating agents.

In FIG. 1, 1 is a lubricant, 2 is an insulator that insulates the lubricant 1 from other bearing members, and 3, 4, and 5 are balls, outer rings, and inner rings of ball bearings, respectively. Reference numeral 6 denotes a rotating shaft, 7 denotes a casing for fixing the bearing, and 8 denotes a power supply for giving a potential difference between the lubricant 1 and the outer shaft 4 of the bearing. In the bearing thus configured, when a potential difference is applied between the lubricant 1 and the outer ring 4 by the power supply 8, a discharge occurs between the two because the atmosphere is vacuum, and the lubricant is ionized by the discharge. To the outer ring to form a thin film. By performing this operation as needed during the operation of the equipment, a lubricating thin film can be replenished and formed, and the life of the bearing can be drastically extended.

In the case of this example, since the lubricant 1 and the plate 1 'on the facing surface are seed materials, it is possible to prevent contamination to the surroundings. In the case of this example, if the outer ring 4, the ball 3, and the inner ring 5 are conductors and are conductive, a thin film can be formed on the inner and outer rings and the ball.

FIG. 2 shows another embodiment, in which a lubricant 1 is used for a part of a peripheral member of a ball bearing. In this example, a thin film having lubricity can be formed by the same operation as in the first embodiment.
Also in this case, the surroundings are prevented by the shield plates 9, 9 '.

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

When the atmosphere is in a high vacuum such as in outer space and discharge does not occur, only when it is desired to supply and form a thin film to the bearing, gas is introduced from the gas supply device 10 to a pressure at which discharge is possible, A discharge is caused by applying a potential difference. In this case, among the various gases such as argon, oxygen, and nitrogen, the most suitable gas may be used according to the lubricant 1 to be used.

The embodiment shown in FIG. 4 shows an embodiment using a sliding bearing as a bearing. For plain bearings,
By the same operation as the embodiment shown in FIGS. 1 to 3,
The thin film can be replenished and formed as needed, and the life can be extended. In the case of plain bearings,
Since the sliding bearing 11 and the shaft 6, that is, the mating surface received by the bearing slide directly, as shown in this example, the lubricant 1, the shaft 6 and the mating surface received by the bearing are used as the conductor. Apply a potential difference between them to form a film
Can be replenished. In this embodiment, a slip ring is used as an example of a means for conducting electrical connection with the shaft 6.

The example shown in FIG. 5 is an example in which this embodiment is applied to a linear motion ball bearing. FIG. 6 is an example applied to a linear sliding bearing. In the embodiment shown in FIGS. 5 and 6, the same operation as the embodiment shown in FIGS. 1 to 4 makes it possible to replenish and form a thin film of the lubricant 1 on the sliding surface. It is possible to extend the life of the device dramatically.

〔The invention's effect〕

According to the present invention, a bearing for a device operated in a vacuum,
Since the lubricant can be replenished and formed as needed during the operation of the equipment, the equipment can be operated stably for a long time, and the life can be greatly extended.

[Brief description of the drawings]

FIGS. 1 to 6 are views 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, 10 gas supply device, 11 slide bearing, 12 linear ball bearing, 13 slip ring .

Claims (9)

(57) [Claims] In a bearing used in a vacuum, at least one of the members having a sliding portion is made of a conductor, and one part of another member of the bearing or one part of a peripheral member. Is composed of a soft metal, a member having the sliding portion is insulated from the soft metal, and a member having the sliding portion is connected to a current between the soft metal and the member. By giving a potential difference to the space between them and causing a discharge,
A lubricating device for a vacuum bearing, wherein a soft metal film is supplied to and formed on a sliding portion of a member requiring a sliding portion. 2. The lubricating device according to claim 1, wherein a discharge is generated during operation or stoppage of the device to replenish and form the soft metal film. 3. A lubrication method for a vacuum bearing according to claim 1, wherein a shield plate is provided to prevent soft metal from adhering to and contaminating members other than the bearing due to electric discharge. 4. A lubricating device for a vacuum bearing according to claim 1, further comprising means for changing an atmospheric pressure when discharging is performed by applying a potential difference. 5. The lubricating device for a vacuum bearing according to claim 1, wherein the bearing is a ball bearing. 6. A lubrication method for a vacuum bearing according to claim 1, wherein the bearing is a plain bearing. 7. A lubricating device according to claim 6, wherein a mating surface received by the bearing is used as a conductor to insulate it from the soft metal,
By providing means for energizing between the power supply and the mating surface, a potential difference is given to the space between the soft metal and the mating surface,
A lubricating device for a vacuum bearing, wherein a soft metal film is replenished and formed on a mating surface. 8. A lubricating device for a vacuum bearing according to claim 1, wherein a solid lubricant is used in place of said soft metal. 9. A lubricating device for a vacuum bearing according to claim 1, wherein a polymer composite material is used in place of said soft metal.