JPH1137158A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure excellent lubricating ability so as to improve durability by forming a hard layer, formed of TiN, TiCN, or the like, on the friction face or contact face of a bearing ring or a rolling element, and forming a solid lubricating layer, formed of an MoS2 film, on the surface of the hard layer. SOLUTION: A rolling bearing has a bearing ring, rolling elements and a cage as components. A hard layer is formed on the rolling friction face or sliding contact face of the bearing ring or rolling element, and a solid lubricating layer formed of an MoS2 film is formed on the surface of the hard layer. As the hard layer, a film of TiN, TiCN, CrN, Cr2 N, or the like superior in surface pressure withstanding strength to a TiC film, and a chrome metal film or chrome plated film can be used. Not the independent layer of each film but multilayer structure can also be formed. As a method of forming the hard film, an ion plating method is effective from the viewpoint of a forming condition and workability. The hard layer and solid lubricating layer can be formed on the rolling friction face or sliding contact face of the cage, but molding out of self-lubricating resin is also possible. With this constitution, durability is considerably improved under high vacuum and high load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rolling bearing having durability under a high load in a vacuum.

[0002]

2. Description of the Related Art In a rolling bearing used in a vacuum, gold, silver, lead, or the like is formed on a surface of a bearing component that generates rolling friction or sliding friction, for example, a rolling surface of an inner or outer ring or a surface of a rolling element. A solid lubricating film made of a soft metal or a layered material such as molybdenum disulfide is formed to lubricate the bearing.

Particularly, molybdenum disulfide (MoS ₂ ) is used in combination with a retainer made of a fluororesin,
The durability is improved by lubricating the transfer film from the cage. Furthermore, it has been proposed to form a hard layer of TiC as an underlayer in order to increase the durability of the MoS ₂ film under a high load.

[0004]

SUMMARY OF THE INVENTION However, TiC
Although the film has high hardness, there is a problem that the film is easily peeled off from the base material by repeated rolling due to a large internal compressive stress. Further, the processing for forming the TiC film requires the use of acetylene gas or methane gas. These gases have high flammability or difficult to control the gas pressure, and therefore have problems in forming conditions and workability.

An object of the present invention is to prevent peeling of a coating film under high load conditions on a rolling friction surface or a sliding contact surface of a bearing ring, a rolling element, and its retainer constituting a rolling bearing, and to provide a high load in a vacuum. An object of the present invention is to ensure stable lubrication of a rolling bearing under conditions and improve durability.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a rolling bearing comprising a raceway, a rolling element and its retainer as components, and a rolling friction surface of the raceway or the rolling element. Alternatively, use TiN on the sliding contact surface.
A hard layer selected from a film, a TiCN film, a CrN film, and a Cr ₂ N film is formed, and a solid lubricating layer made of a MoS ₂ film is formed on the surface of the hard layer. Further, the retainer can be formed from a self-lubricating resin.

[0007] The hard layer formed on the friction surface of the bearing component can reduce the deformation under a high load in a vacuum and can surely support the load. For this reason, local peeling and abrasion of the solid lubricating layer formed of the MoS ₂ film formed on the hard layer can be suppressed, and the durability of each of the hard layer and the solid lubricating layer can be improved. Therefore, the durability of the rolling bearing under a high load in a vacuum can be improved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A rolling bearing according to the present invention
The bearing ring, the rolling element and its retainer as constituent parts, and the rolling friction surface or the sliding contact surface of the bearing ring or the rolling element,
A hard layer is formed, and MoS ₂ is formed on the surface of the hard layer.
A solid lubricating layer composed of a film is formed.

As the hard layer, a TiN film, a TiCN film, a CrN film, a Cr ₂ film having a higher surface pressure resistance than a TiC film.
An N film or the like can be used, and a chromium metal film or a chromium plating film can also be used. In addition, a multilayer structure such as a two-layer structure in which a TiN film and a TiCN film are combined may be used instead of a single layer of each of the above films.

There are various methods for forming the hard film. When the ion plating method is employed, the use of a flammable gas such as acetylene gas or methane gas can be used in a small amount, and the gas pressure can be easily controlled. Therefore, it is effective in terms of forming conditions and workability. In addition, since a film having different components can be continuously formed, a multilayer film can be formed by changing the components and concentrations of the film forming gas in multiple stages.

In this ion plating method, a gas containing a coating component to be formed is introduced into a vacuum vessel, a DC voltage is applied to the coated component to generate an arc discharge, and the coating is formed under the discharge. Is the way. The gas used at this time is an inert nitrogen gas (C ₂ H in TiCN).
_{The two} gases are small. ).

In the above-mentioned rolling bearing, the cage is
The hard layer and the solid lubricating layer may be formed on the rolling friction surface or the sliding contact surface, but may be formed from a resin having self-lubricating properties. Examples of such a resin having self-lubricating properties include a fluorine resin.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Angular contact ball bearings (NTN: F-) with raceways (inner and outer rings) and rolling elements (balls) made of stainless steel
SF863), and a TiN film (T
iN film thickness: 0.5 μm), and Mo
An S ₂ film (MoS ₂ film thickness: 0.3 μm) was formed. The inner and outer rings, balls and cage made of fluororesin (NT
Angular contact ball bearings were assembled using BEAREE FL3800 manufactured by N Company.

An angular ball bearing is assembled by using the obtained parts, a load (GPa) of the surface pressure shown in FIG. 1 is applied, a durability life test is performed at a rotation speed of 2500 rpm, and the inner and outer rings after the test are completed. The wear state of the rolling surface and the surface of the ball was examined by microscopic observation. In addition, the test is 10 ^-6 ~
The test was performed in a vacuum of 10 ^-7 Torr. The result is shown in FIG.

In addition, a durability life test was carried out in the same manner as described above for an angular ball bearing in which only a MoS ₂ film was formed without forming a TiN film on the rolling surfaces of the inner and outer rings and the surface of the rolling element. The result is shown in FIG.

As a result , it became clear that the provision of the TiN film increased the durability life by 6 to 20 times.

[0017]

According to the present invention, by providing a hard film on the friction surface of the bearing component, the durability of the solid lubrication film provided on the friction surface under high vacuum and high load can be increased. It is considered that a good effect is also exerted on the durability of the transfer film from the retainer made of the fluororesin, and both effects greatly improve the durability.

Further, by employing the ion plating method, the workability of the treatment of the hard film layer composed of the TiN, TiCN, and Cr-based coatings is improved, so that the productivity of the bearing can be improved.

Further, even when a WS ₂ film having the same kind of properties as the MoS ₂ film as the solid lubricating film according to the present invention is used, the same effect can be obtained by providing the hard film.

[Brief description of the drawings]

FIG. 1 Results of durability life test

Claims (2)

[Claims] In a rolling bearing comprising a raceway, a rolling element and its retainer as components, a TiN film, a TiC film is formed on a rolling friction surface or a sliding contact surface of the raceway ring or the rolling element.
N film, rolling bearings CrN film, to form a hard layer selected from Cr ₂ N film, characterized in that the formation of the solid lubricant layer consisting of MoS ₂ film on the surface of the hard layer. 2. The rolling bearing according to claim 1, wherein the cage is made of a self-lubricating resin.