JPH09229077A - Ceramics bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To favorably maintain lubricating ability of the rolling face and the sliding face of a ceramics bearing for a long term. SOLUTION: This ceramics bearing is formed so that at least one of two members 1 or 2 and 3 relatively rolling or sliding is made of ceramics, fluoridized compound layer 5 of metal element constituting the ceramic material is formed on the rolling or sliding face of the members 1, 2, 3 made of ceramics. The fluoridized compound layer 5 is formed by changing the composition of the surface layer of the member made of ceramic itself, separation in case of what is called a coating film is not generated, and the lubricating ability is very excellent, hence frictional resistance is reduced so as to restrain abrasion, and rolling or sliding motion is made smooth for a long term.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a ceramic bearing. In particular, it relates to a material suitable for use in a vacuum environment, a high temperature environment, a low temperature environment, a corrosive environment, and the like.

[0002]

2. Description of the Related Art Heretofore, the applicant of the present application has made various studies on rolling bearings and sliding bearings made of ceramics. In the first place, ceramic rolling bearings and sliding bearings can be suitably used in environments where general lubricants such as grease and oil cannot be used, but in order to improve the smoothness of rolling and sliding parts. It is considered to coat the rolling surface or the sliding surface with a solid lubricant. As the solid lubricant, for example, gold,
Examples thereof include soft metals such as silver, copper, tin, and lead, and fluororesins (for example, PTFE: polytetrafluoroethylene).

[0003]

By the way, in the above-mentioned coating film, abrasion, peeling, etc.
Problems such as difficulty in holding for a long period of time are pointed out. In the case of direct contact without a lubricating film, adhesive wear is less than that of metal, but friction resistance during rolling and sliding increases and smoothness decreases. In addition, since ceramics have a much higher hardness than steels and therefore have a high surface pressure, in extreme cases, the rolling and sliding surfaces may be worn or damaged early and become rough, causing vibration or vibration. This leads to an increase in noise.

Therefore, an object of the present invention is to make it possible to maintain the lubricity of rolling surfaces and sliding surfaces in a ceramic bearing for a long period of time.

[0005]

The ceramic bearing of the present invention has two members out of two members that relatively roll or slide.
At least one is formed of ceramics mainly composed of silicon nitride, and a fluoride compound layer with a constituent metal element of the ceramics material is formed on the rolling / sliding surface of the ceramics member. There is.

In the present invention as described above, since the surface layers of the rolling surface and the sliding surface have good lubricity, peeling such as the coating film is eliminated, and the friction resistance is reduced to cause abrasion. Since it is suppressed, rolling and sliding motions are smooth for a long period of time.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below with reference to the embodiments shown in FIGS.

FIG. 1 shows an embodiment of the present invention.
[Fig. 3] is a vertical sectional view of an upper half of a rolling bearing. In the figure, A indicates the whole of a radial type rolling bearing, and here, an inner ring 1, an outer ring 2, a spherical rolling element 3, and a cage 4 are shown.
As an example, a deep groove type ball bearing including In this rolling bearing A, a fluoride compound layer 5 is formed on the surfaces of the raceways of the inner and outer races 1 and 2 and the surface of the rolling elements 3.

The inner and outer races 1, 2 and the rolling element 3 are made of a ceramic material mainly composed of silicon nitride. As the ceramic material, as a sintering aid, yttria (Y ₂ O ₃ ) and alumina (Al ₂ O ₃ ), and other materials such as aluminum nitride (AlN) and titanium oxide (TiO 2)
₂ ), silicon nitride (Si ₃ N ₄ ) using spinel (MgAl ₂ O ₄ ), and alumina (Al ₂
O ₃ ), silicon carbide (SiC), zirconia (Zr
O ₂ ), magnesium oxide (MgO), aluminum nitride (A
In) can be used. However, only the rolling elements 3 may be made of a ceramic material, and the inner and outer rings 1, 2 may be made of a metal material. Examples of this metal material include high carbon chromium bearing steel such as JIS standard SUJ2. When corrosion resistance is required,
A martensitic stainless steel such as JIS SUS440C, for example, a metal material obtained by subjecting a precipitation hardening stainless steel such as JIS SUS630 to an appropriate hardening heat treatment is preferable. For light-load applications, for example, austenitic stainless steel such as JIS SUS304 can be used.

The cage 4 is made of synthetic resin material in addition to mild steel such as JIS standard SPCC material. As a synthetic resin material, general polyamide resin (nylon 66)
In addition to thermoplastic resins having heat resistance, for example, polytetrafluoroethylene (hereinafter abbreviated as PTFE), fluorine-based resins such as ethylene tetrafluoroethylene (ETFE), polyether ether ketone (PEEK), and polyphenylene sulfide (PPS). ), Polyether sulfone (PES), and engineering plastics such as nylon 46 can also be used. As the form of the cage, not only the waveform shown in the figure but also a crown type is used.

The fluoride compound layer 5 is made of silicon fluoride when silicon nitride or silicon carbide is used as ceramics, and is aluminum fluoride when alumina or aluminum nitride is used, and zirconia is used. In the case of zirconium fluoride, when magnesium oxide is used,
It is magnesium fluoride. Such a fluorinated compound layer 5
Is formed as follows. For example, when silicon nitride is used as the ceramic, the fluorinating agent is applied to all the surfaces of the target ceramic inner / outer rings 1 and 2 and the rolling element 3 by ion implantation or CVD. Is injected to a required depth, and is allowed to undergo reaction diffusion as necessary, the surface regions of the silicon nitride (Si ₃ N ₄ ) which is the main composition of the raceway grooves of the inner and outer rings 1 and 2 and the rolling element 3 are It is fluorinated and becomes silicon fluoride (SiF ₄ ). In other words, the surface portions of the inner and outer rings 1 and 2 and the rolling elements 3 are modified,
It has excellent lubricity. Here, the fluorinated compound layer 5 is formed, for example, in a region from the surface to an appropriate depth of, for example, about 0.5 μm. The fluorinating agent used is F
Ion species containing (fluorine) or F, such as CF ₄ , B
F ₂ ⁺ , CHF ₃ , SF _{6 and the} like can be mentioned. In the case of the ion implantation method, for example, the ion implantation voltage is 30 to 200 KeV,
The ion implantation amount is set to 10 ¹⁴ to 10 ¹⁶ K / cm ² .

In such a rolling bearing A, the inner / outer rings 1 and 2 and the rolling element 3 themselves are changed in rolling, and the composition of the surface layer of the sliding surface is changed. Further, since it has extremely excellent lubricity, frictional resistance is reduced, wear is suppressed, and rolling and sliding operations are smooth for a long period of time. Therefore, the rolling torque characteristic and the vibration / noise characteristic of the rolling bearing A are improved.

By the way, the present invention is not limited to the above-mentioned embodiments, and various applications and modifications can be considered.
For example, in the embodiments, deep groove type ball bearings are cited as the bearing type, but the present invention can be applied to other types of rolling bearings and various types of slide bearings. In addition, the fluorinated compound layer 5
May be formed only on at least a member formed of ceramics among the bearing components, but the formation target is not particularly limited.

[0014]

According to the ceramic bearing of the present invention, the surface of the portion that rolls or slides in the ceramic member is
It has excellent lubricity and has been modified to have almost no peeling or wear, so rolling and sliding operations can be smoothed for a long period of time, and torque characteristics and vibration / noise characteristics can be improved. Become.

Therefore, the ceramic bearing of the present invention is
In particular, when used in a harsh environment such as a vacuum environment, a high temperature environment, a low temperature environment, or a corrosive environment, it is suitable because it can achieve a long life.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an upper half of a ceramic bearing according to an embodiment of the present invention.

[Explanation of symbols]

 A ceramic bearing 1 inner ring 2 outer ring 3 rolling element 4 cage 5 fluoride compound layer

Claims (1)

[Claims] 1. A ceramic bearing in which at least one of two members that relatively rolls or slides is formed of ceramics, wherein the ceramics member has a rolling / sliding surface on which the ceramics A ceramic bearing, wherein a fluorinated compound layer with a constituent metal element of the material is formed.