JP3350178B2 - Solid lubricated bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid lubricating bearing used as a protective bearing for a rotating body in a magnetic bearing type turbo molecular pump, for example.

[0002]

2. Description of the Related Art Conventionally, a magnetic bearing type turbo-molecular pump of this type has a protection bearing 1 as shown in FIG. , But comes into contact with the rotating body 2 only when the function of the magnetic bearing 3 for supporting the rotating body 2 in a fixed position is lost for some reason.

Such a protective bearing 1 is constituted by a solid lubricated bearing as shown in FIG. 4, and the solid lubricated bearing is formed by first and second angular bearings 4 and 5 arranged in a double row. .

The side surfaces A ₁ and A ₂ of the outer races 4 a and 5 a in the two angular bearings 4 and 5 are tightly fixed to each other, while the side surfaces B ₁ and B _{2 of the} inner races 4 b and 5 b are fixed.
The play is set such that a certain gap a is formed between them. That is, the inner races 4b and 5b have their side surfaces B ₁ and B ₂ facing each other with a certain gap a therebetween, and can rotate independently of each other. The reason for setting the play and providing the gap a is that the inner rings 4 b and 5 b and the rolling elements 4
This is to prevent the rotating body 2 from becoming heavy due to the expansion of c and 5c and the generation of a thrust force during the expansion.

In a vacuum environment, lubricants such as oils and fats evaporate and contaminate the inside of the vacuum vessel and cannot be used. Therefore, the surfaces of the angular bearings 4 and 5 are replaced with lead, oil or the like instead of lubricants. A highly extensible metal such as silver or gold is coated as the solid lubricant 6.

[0006] Such coating of the solid lubricating material 6 is normally performed by the rolling elements 4c, 5c and the inner and outer rings 4a, 4a.
It is sufficient to apply it to the race surfaces b, 5a and 5b, but it is easier and easier to apply the entire surface than to the partial surface as described above. Has been applied to the entire outer periphery of.

[0007]

However, in the conventional solid lubricating bearing as described above, the outer peripheral surfaces of both angular bearings 4 and 5 are coated with the solid lubricating material 6, so that the angular bearing 4 ,
5 is subjected to a thrust load by the rotating body 2, and the inner ring 4b,
When the gap a between the inner rings 4b and 5b disappears and a force acts between the inner rings 4b and 5b, the solid lubricants 6 adhere to each other. The moving bodies 4c and 5c expand, and a thrust force is generated during the expansion, so that the effect of preventing the rotating body 2 from becoming heavy cannot be obtained (rotation becomes heavy if thermal expansion occurs while being adhered). In addition, since the relative positions of the inner rings 4b and 5b are not fixed, the cores of the inner rings 4b and 5b may be displaced and adhere to each other during the adhesion.

In such a situation of adhesion, once the rotating body 2 comes into contact with the angular bearings 4 and 5, the rotational resistance of the rotating body 2 increases, and the load applied to the rotating body 2 increases. At the same time, since the damping between the rotating body 2 and the angular bearings 4 and 5 becomes large, it may not be possible to easily return from the state where the rotating body 2 and the angular bearings 4 and 5 are in contact with each other.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a solid lubricated bearing in which adhesion between inner rings is prevented.

[0010]

In order to achieve the above object, the present invention comprises first and second rolling bearings, and both rolling bearings are fixedly attached to one side of each outer ring. In a solid lubricated bearing, one side surfaces of the inner ring are provided to face each other with a gap therebetween, and each inner diameter surface is coated with a solid lubricant .
One side of the inner ring of the rolling bearing
And a coating layer made of a different material is provided on one side surface of the inner ring of the second rolling bearing facing the second rolling bearing .

[0011]

According to the present invention, when a thrust load is applied to the first and second rolling bearings, the gap between the inner rings disappears, and when a force acts between the inner rings, the inner rings are interposed through the coating layers of different materials. Touching.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a solid lubricated bearing according to the present invention will be described below in detail with reference to FIGS.

As shown in FIG. 1, the solid lubricated bearings have first and second rolling bearings, which are arranged in a double row.
And second angular bearings 4, 5;
And outer ring 4 of both angular bearings 4 and 5
The side surfaces A ₁ and A _{2 of} the inner rings 4 a and 5 a are tightly fixed to each other, while the side surfaces B ₁ and B _{2 of the} inner rings 4 b and 5 b are provided to face each other with a certain gap a. Since this is the same as in the conventional example, the same reference numerals are given to the same members, and the detailed description is omitted.

[0014] In the solid lubricant bearing, while the copper coating layer 7 on one side B ₂ of the inner race 5b of the second angular bearing 5 to a material of copper as shown in the figure are provided, the on one side surface B ₁ of the inner ring 4a in one of the angular bearing 4 is formed of lead coating layer 8, the material of lead, copper coating layer 7 and the lead coating layers 8 are opposed to each other.

That is, one side surface B ₂ of the inner ring 5b in the second angular bearing 5 and one side surface B ₁ of the inner ring 4b in the first angular bearing 4 are provided with a copper coating layer 7 as a coating layer made of different materials. It is provided so as to face through the lead coating layer 8.

[0016] Incidentally, one aspect B ₂ than the portion of the inner ring 5b of the second angular bearing 5, in particular the rotary body 2 as inner diameter surface C _1, C ₂ of the angular contact bearings 4,5
In order to ensure lubrication during sliding with the rotor 2, a lead coating layer 8 made of lead as a solid lubricant is provided on a surface which is in direct sliding contact with the rotor 2.

According to such a solid lubricated bearing,
When the thrust load by the rotating body 2 is applied to the angular bearings 4 and 5, the gap a between the inner rings 4b and 5b disappears,
A force acts between the inner rings 4a and 5b.
One side surfaces B ₁ and B _{2 of the} b and 5b are in sliding contact with each other via the copper coating layer 7 and the lead coating layer 8, that is, the dissimilar metals are in sliding contact with each other, so that the inner rings 4b and 5b are less likely to adhere to each other. Smooth rotation of the inner rings 4b, 5b is obtained.

Therefore, in the solid lubricated bearing of the above embodiment, the thrust load by the rotating body is applied to the angular bearing, the gap between the inner rings disappears, and even when a force acts between the inner rings, the inner rings are coated with copper. Since the layers and the lead coating layer are in sliding contact with each other via a dissimilar metal, adhesion between the inner rings is prevented, and problems such as an increase in the load applied to the rotating body are eliminated.

[0019] Incidentally, distribution to the one side B ₂ of the inner ring 5b in one aspect B ₁ and the second angular bearing 5 of the inner ring 4b in the first angular bearing 4, a copper coating layer 7 and the lead-coating layer 8, respectively When the copper coating layer 7 is provided, the copper coating layer 7 is provided on the entire outer periphery of the first and second angular bearings 4 and 5 as shown in FIG.
This forms the lead-coating layer 8 over the entire surface of the copper coating layer 7, then scraped lead coating layer 8 only one side B ₂ of the inner race 5b of the second angular bearing 5, the underlying copper coating layer 7 May be configured to be exposed.

The copper coating layer 7 may be formed on one side surface B ₁ of the inner ring 4 b of the first angular bearing 4, and the lead coating layer 8 may be formed on one side surface B ₂ of the inner ring 5 b of the second angular bearing 5. .

The coating layers made of different materials are not limited to the combination of the copper coating layer 7 and the lead coating layer 8, but may be appropriately selected and applied as long as the combination of materials hardly causes adhesion.

[0022]

According to the solid lubricating bearing according to the present invention, as described above, one side of the inner race in the first rolling bearing and one side of the inner race in the second rolling bearing are coated with different materials. Because each layer is provided, a thrust load is applied to the rolling bearing by the rotating body, the gap between the inner rings disappears, and even when a force is applied between the inner rings, the inner rings pass through the dissimilar metal between the copper coating layer and the lead coating layer. The sliding contact prevents the inner rings from adhering to each other, thereby eliminating problems such as an adverse effect such as an increase in load applied to the rotating body.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a solid lubricated bearing according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the solid lubricated bearing according to the present invention.

FIG. 3 is a cross-sectional view of a turbo-molecular pump incorporating a solid lubricated bearing.

FIG. 4 is a sectional view of a conventional solid lubricated bearing.

[Explanation of symbols]

 4 1st angular bearing (1st rolling bearing) 5 2nd angular bearing (2nd rolling bearing) 7 Copper coating layer 8 Lead coating layer

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16C 19/00-19/56 F16C 33/30-33/66 F16C 32/00-32/06

Claims (1)

(57) [Claims] 1. A rolling bearing comprising first and second rolling bearings, wherein both rolling bearings are provided so that one side surface of each outer ring is closely fixed and one side surface of each inner ring faces each other with a gap therebetween. And a solid lubricated bearing having a solid lubricant coated on each inner diameter surface, wherein one side of the inner ring of the first rolling bearing and
One of the inner rings of the second rolling bearing facing each other with a gap therebetween.
A solid lubricated bearing, wherein a coating layer made of a different material is provided on each of the side surfaces .