JPH07217662A - Solid-lubricated rolling bearing - Google Patents

Abstract

PURPOSE:To provide a solid-lubricated rolling bearing generating little dust so as to be ideally usable for a device needing a clean atmosphere such as a semiconductor manufacturing device and usable also in a vacuum. CONSTITUTION:Plural rolling elements 4 are rotatably held between an inner ring 2 and an outer ring 3 through a crown cage 5, and shield plates 6 are disposed at both end parts of the outer ring 3 in such a way as to come in contact with the crown cage 5, thus forming a rolling bearing 1. Either one of the crown cage 5 and shield plate 6 is formed of material containing fluororesin. Abrasion grain containing fluororesin is generated in association with the rotation of the rolling bearing 1, and this abrasion grain is shifted to the raceway track surface of the inner and outer rings, the pocket inner peripheral surface of the cage 5 and the rolling surface of the rolling element 4 so as to form lubricating coats at these parts. In addition, the cage 5 and the shield plate 6 is formed of materials to become mutually counter electrodes in an electrification rank. In association with the rotation of the rolling bearing 1, both members slide so as to generate static electricity, and the abrasion grain is held in the internal space of the bearing 1 by a shielding effect due to this static electricity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid lubrication rolling bearing, and more particularly to a solid lubrication rolling bearing which is suitable for use in semiconductor manufacturing equipment and other equipment that requires a clean atmosphere and which can be used even in a vacuum state.

[0002]

2. Description of the Related Art A rolling bearing having a structure that uses oil or grease as a lubricant can withstand high speed rotation and a large load because of its excellent lubricity, but on the other hand, oil and grease scatter as the bearing rotates, Alternatively, it has the drawback that it cannot be used when it is exposed to a vacuum condition or a device that requires a clean environment such as a clean room or semiconductor manufacturing device, because it pollutes the external environment of the bearing due to vaporization due to temperature rise. There is.

Therefore, in a clean room, a semiconductor manufacturing apparatus, or a vacuum state, a bearing having a solid lubricating film formed on the raceway surface or the surface of the rolling element is used. As the solid lubricating film, gold, silver, lead, molybdenum disulfide, tungsten disulfide or fluororesin is generally used.
Among these lubricating films, gold, silver, lead and fluororesin are gradually scraped off from the original film-forming surface by the frictional force generated by the rotation of the bearing, and the wear particles scraped off against each other. Lubrication is performed by transferring to a surface and forming a thin film on the surface.

On the other hand, molybdenum disulfide and tungsten disulfide are layered and have cleavage planes themselves,
The cleaved surface is gradually worn to develop lubricity.

[0005]

By the way, in recent years, there has been a tendency toward miniaturization and high integration of various electronic elements including semiconductor elements, and accordingly, a small amount of particles greatly influences the performance and reliability of products. Has become. For this reason, there is a tendency for the demand for low dust generation to increase more and more for bearings used in a clean environment such as semiconductor manufacturing equipment.

However, all the above solid lubricating films are self-sacrificing type lubrication, and the generation of wear particles is unavoidable.
The situation is not sufficient to meet the above demands. Therefore, it is an object of the present invention to provide a solid lubrication rolling bearing which is suitable for use in an apparatus that requires a clean atmosphere, such as a semiconductor manufacturing apparatus, which produces little dust, and which can be used even in a vacuum state.

[0007]

SUMMARY OF THE INVENTION The above object is to rotatably hold a plurality of rolling elements between a pair of bearing rings via a cage, and to further shield plates at both ends of one bearing ring. And a shield plate disposed in contact with at least one of the retainer and the other race ring, and the shield plate and the retainer or the other race ring. At least the contact portion thereof is formed of a material which is a counter electrode to each other in the charging train.

Further, a similar object is that, in the solid lubrication rolling bearing, at least one of the shield plate and the cage is made of a material containing a fluororesin, and is scraped off from the shield plate or the cage as the rolling bearing rotates. Wear particles are transferred to the raceway surface of the bearing ring, the inner peripheral surface of the pocket of the cage and the rolling surface of the rolling element to form a lubricating coating, which is also achieved by a solid lubrication rolling bearing. It

Further, a similar object is that, when the shield plate comes into contact with the other race ring, the other race ring is provided at a portion which comes into contact with the shield plate from a material which is a counter electrode to the shield plate in the charging train. It is also achieved by a solid lubricated rolling bearing, characterized in that an annular member is attached.

[0010]

[Operation] According to the present invention, the wear particles generated inside the bearing can be prevented from scattering to the outside of the bearing by the shield plates arranged at both ends of the bearing ring, and the cage and the shield plate can be connected to the opposite electrode of the charging column. When the bearing is rotated, the both members slide with each other as the bearing rotates, and static electricity is generated, and wear particles can be retained inside the bearing due to the shielding effect by the static electricity. Therefore, the wear particles do not contaminate the environment outside the bearing, and can be suitably used for an apparatus or the like that requires a clean atmosphere.

Further, by forming at least one of the cage and the shield plate from a material containing a fluororesin, both the members slide with the rotation of the bearing to generate wear particles having lubricity. Wear particles transfer to the raceway surface of the bearing ring, the inner peripheral surface of the cage pocket, and the rolling surface of the rolling elements to form a lubricating film, so excellent lubrication is possible without forming a lubricating film in advance on these parts. And the manufacturing process of the bearing can be simplified.

Further, the wear particles are gradually generated as the bearing rotates, and are retained inside the bearing by the shield plate and the shielding effect by static electricity, so that the lubricity can be maintained for a longer period of time.

[0013]

EXAMPLES The present invention will be described in detail based on examples. However, the present invention is not limited to the following examples. FIG. 1 is a cross-sectional view of essential parts showing a first embodiment of a solid lubrication rolling bearing according to the present invention. Rolling bearing 1
Is formed by arranging a plurality of rolling elements 4 between the inner ring 2 and the outer ring 3 and holding the rolling elements 4 at equal intervals along the circumference by a crown-shaped cage 5.

In the present invention, the shield plate 6 is further provided so as to come into contact with the crown-shaped cage 5. Shield plate 6
As shown in the drawing, is an annular plate member having a width that is the difference in diameter between the inner ring 2 and the outer ring 3, and is fixed to both ends of the outer ring 3. Further, the rolling bearing 1 according to the present invention has a solid state on the outer peripheral surface (raceway surface) of the inner ring 2, the inner peripheral surface (raceway surface) of the outer ring 3 and the surface (rolling surface) of the rolling element 4 similarly to the conventional bearing. A lubricating film may be formed, or at least one of the crown-shaped cage 5 and the shield plate 6 may be formed of a material containing a fluororesin. In that case, as the rolling bearing 1 rotates, the crown-shaped cage 5 and the shield plate 6 slide to generate wear particles containing a fluororesin, and these wear particles are generated on the raceways of the inner ring 2 and the outer ring 3, It is transferred to the inner peripheral surface of the pocket of the crown-shaped cage 5 and the rolling surface of the rolling element 4 to form a lubricating coating on these portions. The wear particles are generated gradually and continuously with the rotation of the rolling bearing 1, so that the lubricating action can be maintained for a long period of time.

Further, in the present invention, the combination of the materials of the two members is defined so that the materials forming the crown-shaped cage 5 and the shield plate 6 are substances having opposite electrodes in the charging train. Characterize. For example, when the shield plate 6 is formed of a material containing a fluororesin, the crown-shaped cage 5 is a substance that becomes a counter electrode of the fluororesin in the charging train, such as glass fiber, polyamide, polyacetal,
It can be formed of a material containing polyimide, polyamideimide, or the like, or a mixture of these resins and glass fibers.

Both members of the shield plate 6 and the crown-shaped cage 5 can be made of a fluororesin-containing material. In that case, the fluororesin is used so that the two members are opposite to each other in the charging train. It is necessary to change the substance mixed with. The material forming the crown-shaped cage 5 and the shield plate 6 can be reversed from the above.

By defining the combination of the materials forming the crown-shaped cage 5 and the shield plate 6 as described above, the rotation of the rolling bearing 1 causes both members to slide and a charging phenomenon due to friction occurs. The static electricity generated by is charged in the internal space surrounded by the shield plate 6 of the bearing 1,
The shielding effect by the static electricity can more effectively suppress the scattering of wear particles to the outside. It should be noted that there is a minute width gap 7 between the inner ring 2 side end of the shield plate 6 and the inner ring 2, but this gap 7 is also sealed by the shield effect due to static electricity, so that wear particles pass through the gap 7. It does not leak outside.

As described above, the wear particles are prevented from scattering outside the rolling bearing 1 due to the shield effect of the shield plate 6 and static electricity, so that the environment outside the bearing 1 is not polluted. The inner ring 2 and the outer ring 3 are often made of a stainless alloy in order to prevent the generation of rust and the like, but some stainless alloys have high conductivity depending on the type. Static electricity generated by sliding on the shield plate 6 may cause a so-called discharge phenomenon through the inner ring 2 and the outer ring 3 to reduce the shielding effect due to static electricity. Therefore, the discharge phenomenon can be suppressed by forming an insulating film on the raceways of the inner ring 2 and the outer ring 3.

Further, although FIG. 1 shows an example in which the shield plate 6 is fixed to the outer ring 3, even if the shield plate 6 is fixed to the inner ring 2 as shown in FIG. Is obtained. FIG. 3 is a cross-sectional view of essential parts showing a modified example of the solid lubrication rolling bearing 1 shown in FIG. As shown in the figure, of the pair of shield plates 6 of the rolling bearing 1, the shield plate 6a on the side that does not contact the crown-shaped holding member 5 has a substantially convex cross section, and is arranged in contact with the rolling element 4. There is. Here, by forming the shield plate 6a with a material containing a fluororesin, the rolling element 4 and the shield plate 6a slide with the rotation of the rolling bearing 1, and the rolling surface of the rolling element 4 is directly lubricated. Property is imparted, wear particles containing fluororesin are generated and transferred to the raceway surfaces of the inner ring 2 and the outer ring 3 and the inner peripheral surface of the pocket of the crown-shaped cage 5, and a lubricating coating is formed on these parts. To be done.

At the same time, the sliding effect between the crown-shaped cage 5 and the shield plate 6 causes a shielding effect due to static electricity, so that scattering of wear particles to the outside of the rolling bearing 1 is effective together with the shield plates 6 and 6a. Can be prevented. Although FIG. 3 shows an example in which the shield plate 6 is fixed to the outer ring 3, the shield plates 6 and 6a may be fixed to the inner ring 2 as in FIG.

FIG. 4 is a sectional view of the essential parts showing a second embodiment of the solid lubrication rolling bearing 1 according to the present invention. In this rolling bearing 1, a corrugated press cage 5a is used instead of the crown cage 5 in the first embodiment, and a shield plate 6 is used.
Is configured to contact the inner ring 2 without contacting the corrugated press holder 5a. The inner ring 2 has a circumferential wall 2a whose end is cut out over the entire circumference thereof, and a charging ring 8 made of a material that is opposite to the material of the shield plate 6 in the charging row is fitted in the cutout. And the shield plate 6
Are attached to the outer ring 3 so as to come into contact with the charging ring 8.

Here, by forming the shield plate 6 from a material containing a fluororesin, the charging ring 8 and the shield plate 6 slide with the rotation of the rolling bearing 1 and wear particles containing the fluororesin are generated. Occurs and the raceways of inner ring 2 and outer ring 3,
It is transferred to the inner peripheral surface of the pocket of the crown-shaped cage 5 and the rolling surface of the rolling element 4, and a lubricating coating is formed on these portions. At the same time, since the shield plate 6 and the charging ring 8 slide, a shield effect due to static electricity is exhibited, so that scattering of wear particles to the outside of the rolling bearing 1 can be effectively prevented together with the shield plate 6. .

Although FIG. 4 shows an example in which the shield plate 6 is fixed to the outer ring 3, the shield plate 6 is the same as in FIG.
May be fixed to the inner ring 2 and the charging ring 8 may be provided on the outer ring 3. Further, the charging ring 8 can be made of a fluororesin-containing material, and the shield plate 6 can be made of a material that is a counter electrode to the charging ring 8 in the charging train. Further, FIG. 5 is a diagram showing an outline of the dust test apparatus used in the present invention.
The test bearing 9 has a housing 11 via a spring 10.
Two of them are mounted inside and rotated by a rotation introducing machine 12 with a magnetic fluid seal. The dust generated from the test bearing 9 due to the rotation is collected in the funnel 13 provided at the lower part of the device, and then the light scattering type particle counter 1
It is sent to 4 and the number of dust particles is counted. (Examples 1 to 6 and Comparative Examples 1 to 3)
The inner ring 2, the outer ring 3 and the rolling element 4 are commonly used, and the materials of the cage 5 and the shield plate 6 and the presence / absence of contact between the cage 5 and the shield plate 6 are changed as shown in Table 1 and shown in FIG. A dusting test was conducted using a dust tester. In addition, in Examples 2 and 3 and Comparative Examples 2 and 3, a solid lubricating film made of MoS ₂ or WS ₂ was previously formed on the inner ring 2, the outer ring 3 and the rolling elements 4.

The test results are also shown in Table 1.

[0025]

[Table 1]

The test conditions are as follows. -Test bearing 608-Axial load 9.8N-Rotational speed 300rpm-Atmosphere In air From the above test results, the materials of cage 5 and shield plate 6 were combined so as to be opposite electrodes in the charging column, and cage 5 and shield were also combined. By contacting the plate 6 (Examples 1 to 6), even if the materials of both members do not come into contact with each other even in a combination that forms a counter electrode in the charging column (Comparative Examples 1 and 2), both members It can be seen that compared with the case where the materials of No. 2 are not opposite to each other in the electrification train and both members are not in contact with each other (Comparative Example 3), the amount of dust generation and the durability life of the bearing are significantly superior.

[0027]

As described above, according to the present invention, the wear particles generated inside the bearing can be prevented from scattering to the outside of the bearing by the shield plates arranged at both ends of the bearing ring, and the cage and the shield can be prevented. By forming the plate and the material on the opposite electrode of the electrification row, both the members slide as the bearing rotates and static electricity is generated, and wear particles are held inside the bearing by the shielding effect due to this static electricity. You can Therefore, the wear particles do not contaminate the environment outside the bearing, and can be suitably used for an apparatus or the like that requires a clean atmosphere.

Further, by forming at least one of the cage and the shield plate with a material containing a fluororesin, both the members slide with the rotation of the bearing to generate wear particles having lubricity. Wear particles transfer to the raceway surface of the bearing ring, the inner peripheral surface of the cage pocket, and the rolling surface of the rolling elements to form a lubricating film, so excellent lubrication is possible without forming a lubricating film in advance on these parts. And the manufacturing process of the bearing can be simplified.

Further, wear particles are gradually generated as the bearing rotates, and are retained inside the bearing by the shield effect of the shield plate and static electricity, so that the lubricity can be maintained for a longer period of time.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a first embodiment of a solid lubrication rolling bearing according to the present invention.

2 is a cross-sectional view of essential parts showing a modified example of the solid lubrication rolling bearing shown in FIG.

FIG. 3 is a cross-sectional view of essential parts showing another modified example of the solid lubrication rolling bearing shown in FIG.

FIG. 4 is a cross-sectional view of essential parts showing a second embodiment of the solid lubrication rolling bearing according to the present invention.

FIG. 5 is a schematic view showing a dust test apparatus used in the present invention.

[Explanation of symbols]

 1 rolling bearing 2 inner ring 2a peripheral wall 3 outer ring 4 rolling element 5 retainer 6 shield plate 7 gap 8 charging ring 9 test bearing 10 spring 11 housing 12 rotation induction machine with magnetic fluid seal 13 funnel 13 14 particle counter 14

Claims (3)

[Claims] 1. A rolling bearing in which a plurality of rolling elements are rotatably held between a pair of bearing rings via a cage, and shield plates are attached to both ends of one bearing ring. The shield plate is disposed in contact with at least one of the cage or the other race, and the shield plate and at least a contact portion of the cage or the other race are in a charging train. A solid-lubricated rolling bearing, which is formed of materials that are opposite to each other. 2. At least one of the shield plate or the cage is made of a material containing a fluororesin, and wear particles scraped off from the shield plate or the cage as the rolling bearing rotates, 2. The solid lubrication rolling bearing according to claim 1, wherein a lubricating coating is formed by transferring to the inner peripheral surface of the pocket of the cage and the rolling surface of the rolling element. 3. When the shield plate comes into contact with the other raceway ring, an annular member made of a material which is a counter electrode to the shield plate in the charging train is attached to a portion of the other raceway ring contacting the shield plate. The solid lubrication rolling bearing according to claim 1, wherein