JP3051880B2 - Solid lubricated rolling bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
Also, the present invention relates to a solid lubricated rolling bearing incorporated in OA equipment, information equipment, and the like in which a fluid lubricant such as grease cannot be used.

[0002]

2. Description of the Related Art Generally, a rolling bearing supplies a lubricant such as grease between an inner / outer ring and a rolling element and between a rolling element and a cage to reduce rolling friction and sliding friction generated therebetween. The durability of the bearing is improved.

When a rolling bearing is used in a vacuum of space equipment or the like, a fluid lubricant having a high vapor pressure such as grease evaporates into the atmosphere and cannot be used. In OA equipment and information equipment, fluid lubricant such as grease that evaporates or leaks from bearings may adhere to a disk or the like and cause error movement of the equipment. Can not be used. For this reason, a rolling bearing used in such an environment requires a solid lubricant that has a low vapor pressure and has no fear of leaking from the bearing.

At present, solid lubricants for rolling bearings include:
Layered material such as molybdenum disulfide, soft metal such as gold, silver and lead, and high molecular weight lubricant such as PTFE and polyimide are widely used.

[0005]

For example, a bearing used for a drive mechanism of a space device uses a solid lubricant obtained by subjecting molybdenum disulfide (MoS ₂ ) to a film treatment by sputtering. This is because molybdenum disulfide is a layered substance-based solid lubricant, and is excellent in low torque property as compared with a soft metal-based solid lubricant. On the other hand, molybdenum disulfide is vulnerable to moisture, and its lubricity deteriorates particularly in an environment where the relative humidity is 65% or more. For this reason, the bearing on which the solid lubricating film of molybdenum disulfide is formed is vacuum-packed after the product is completed, for example, so as to be shielded from the atmosphere.

[0006] However, the above-mentioned bearings are used for assembling equipment.
In many cases, it is exposed to the air during the storage process, etc., and when it is used for a long time, there is a concern that the lubricity may deteriorate. Taking the above space equipment as an example, the reality is that satellites are assembled and stored several months before launch, and during that time bearings are inevitably exposed to the atmosphere, and solids are absorbed by moisture. The lubricity of the lubricating film may be deteriorated.

Further, depending on the device into which the bearing is incorporated,
In some cases, the bearing is required to have a function capable of operating in both vacuum and atmospheric environments, and the above-described bearing cannot meet such requirements.

Accordingly, an object of the present invention is to prevent a solid lubricating film made of molybdenum disulfide from deteriorating due to moisture absorption, and to exhibit the excellent lubricity inherent in the film.
This also provides a solid lubricated rolling bearing for both vacuum and atmosphere.

[Means for Solving the Problems]

In the solid lubricated rolling bearing of the present invention, molybdenum disulfide lubricating film layer and molybdenum disulfide lubricating film layer absorb moisture on at least the surface of the rolling bearing that generates rolling friction or sliding friction. Degradation
In order to prevent this , a multilayer solid lubricating film having a protective film layer of PTFE formed on a lubricating film layer of molybdenum disulfide is formed. The above protective film
As a material for forming the layer, the average molecular weight is 1 × 10 ^{3 to} 3 × 1.
0 ³ PTFE can be used.

[0010]

The PTFE material has excellent moisture resistance and does not attract moisture. By covering the surface of the lubricating film layer of molybdenum disulfide with the protective film layer of PTFE, the penetration of moisture is suppressed, so that the lubricating film layer of molybdenum disulfide does not deteriorate its lubricity due to moisture. Maintain good lubricity over a long period of time. On the other hand, since the PTFE material itself has a self-lubricating property, the lubricating property of the molybdenum disulfide lubricating film layer is not impaired by the presence of the PTFE protective film layer.

[0011]

Embodiments of the present invention will be described below.

FIG. 1 shows an embodiment in which the present invention is applied to a deep groove ball bearing. This bearing includes inner ring 1, outer ring 2, inner and outer rings 1
-It is composed of a plurality of rolling elements 3 interposed between the two, and bearing parts such as a cage 4 for holding the rolling elements 3 at equal circumferential intervals.
On the rolling surfaces of the inner and outer rings 1 and 2 and on the surface of the rolling element 3, there are formed multiple layers of solid lubricating films 5, 6, and 7, respectively.

These solid lubricating films 5, 6, 7 are shown in FIG.
As shown in (the rolling surface portion of the inner ring 1), the lubricating film layer 5a (6) of molybdenum disulfide adhered to the surface of the base material.
a.7a) and a PTFE protective coating layer 5b (6b.7) formed on the lubricating coating layer 5a (6a.7a).
b) and a two-layer structure. Lubricating film layer 5a (6a
In a), molybdenum disulfide is applied by high-frequency sputtering to adhere to the base material surface. The protective coating layer 5b (6b, 7b) is sprayed with, for example, a PTFE solution to form a lubricating coating layer 5a (6a).・ Attached to the surface of 7a). The thickness of each lubricating film layer is 0.2 μm for the lower lubricating film layer 5a (6a ・ 7a) and 0.3 μm for the uppermost protective film layer 5b (6b ・ 7b). , FIG.
In FIG. 2 and FIG. 2, these are considerably exaggerated. Further, the solid lubricating films 5, 6, 7 are not limited to the two-layer structure shown in the drawing, and for example, the lubricating film layers 5a (6a.
7a) Another type of lubricating layer may be interposed under the lower layer, or another type of lubricating layer may be formed above the protective layer 5b.

FIG. 3 shows the results of a life test performed on the deep groove ball bearing having the structure shown in FIG. In the life test, two test bearings supporting a shaft were tested at room temperature and contact surface pressure of 60 kg.
The bearing was rotated under the conditions of f / mm ² and 2500 rpm, and the total friction torque of the two test bearings was 100 gcm.
The point at which it reached was the life. The test bearing is a test bearing in which a solid lubricating film consisting only of molybdenum disulfide is formed on the rolling surface of the inner and outer rings and the surface of the rolling element (referred to as bearing A).
And 2 of the test bearing (referred to as bearing B) having the configuration shown in FIG.
Under the above conditions, prepare the bearing A and apply a vacuum of 10 ^-6 T
The bearing B was operated in a vacuum of orr or lower, and in vacuum after being left in saturated steam, and in vacuum after being left in saturated steam. As shown in the figure, the life when the bearing (bearing B) of the present invention is operated in saturated steam is almost the same as the life when the bearing A is operated in a vacuum. Is hardly affected by moisture.

In this embodiment, the solid lubricating films 5, 6 and 7 are formed on the rolling surfaces of the inner and outer rings 1 and 2 and the surface of the rolling elements 3. May be formed on the surface. Also, in FIG.
Solid lubricating films 5, 6, 7 are formed on the entire outer surface of the solid lubricating film. However, unnecessary portions of the solid lubricating film, such as fitting surfaces, are not subjected to film treatment by masking, or are not treated with the final product. It is also possible to remove it before it becomes. Further, the type of the bearing is not limited to the deep groove ball bearing as shown in FIG.

It is known that molybdenum disulfide is excellent in low torque, but slightly inferior in dust generation. The means described below is effective as a means for solving this problem. That is, generally, the PTFE material used as a solid lubricant has an average molecular weight of 2 × 10 ^{5 to} 3
It is a polymer of × 10 ⁵ , and this polymer is used in the above-described embodiment.
Instead of the protective coating layer 5b, the average molecular weight is 1 × 10 ^{3 to} 3
The protective film layer 5b made of × 10 ³ PTFE (referred to as PTFE telomer) is used as the lubricating film layer 5 of molybdenum disulfide.
It is formed in the upper layer of a. The wear powder of the PTFE telomer has excellent transferability and penetrates into minute concave portions of the mating surface to form a lubricating film, so that the wear powder (particles) is hardly scattered and low dust is generated. Further, since the shear resistance is small, the coefficient of friction is small, and excellent lubrication performance is exhibited. This P
By forming the protective coating layer 5b using a TFE telomer, the low dust generation of the bearing is significantly improved as compared with the case using a PTFE polymer. In addition, since the PTFE telomer has the same water resistance as the PTFE polymer, the intended purpose of the present invention is not impaired.

[0017]

As described above, according to the present invention, the protective film layer of PTFE is formed on the lubricating film layer of molybdenum disulfide, so that the lubricating film layer of molybdenum disulfide is formed. Does not deteriorate due to moisture and exhibits good lubricating properties over a long period of time. In addition, the average molecular weight is 1
Protective coating layer made of PTFE of × 10 ³ to 3 × 10 ³
Is formed on top of the molybdenum disulfide lubricating film layer
Prevents moisture deterioration of the molybdenum disulfide lubricating film layer
At the same time as improving the low dust generation of the bearing.
Wear.

[Brief description of the drawings]

FIG. 1 is a sectional view of a deep groove ball bearing showing an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view around a rolling surface of an inner race in FIG.

FIG. 3 is a diagram showing the results of a life test.

[Explanation of symbols]

Reference Signs List 1 inner ring 2 outer ring 3 rolling element 5 solid lubricating film 5a lubricating film layer of molybdenum disulfide 5b protective film layer of PTFE 6 solid lubricating film 6a lubricating film layer of molybdenum disulfide 6b protective film layer of PTFE 7 solid lubricating film 7a disulfide Molybdenum lubricating layer 7b PTFE protective layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16C 33/66 F16C 33/58 F16C 33/32 F16C 33/34

Claims (2)

(57) [Claims] To claim 1, wherein at least the rolling friction or surface causing the sliding friction among the parts constituting the rolling bearing, and a lubricating coating layer of molybdenum disulfide, Jun said molybdenum disulfide
In order to prevent deterioration of the lubricating film layer due to moisture absorption,
PTFE formed on top of a lubricating film layer of molybdenum fluoride
A solid lubricated rolling bearing, wherein a multi-layer solid lubricating film having a protective film layer is formed. 2. The PTFE having an average molecular weight of 1 × 10 ^Three
~ 3 × 10 ^Three 2. The solid lubricating rolling shaft according to claim 1, wherein
Receiving.