JPH1130236A - Bearing metal material and rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make improvements in a frictional characteristic on boundary lubricating conditions, reducing each individual variation in the frictional characteristic on the working conditions of high temperature and high speed, and to prolong the bearing life by forming a thionic acid metallic salt coat on the surface of a bearing metal material. SOLUTION: Those of bearing steel, case hardened steel and high-speed steel as raceway materials, and blanked cage sheet steel, machined cage carbon steel or the like as cage materials are enumerated. A rolling bearing which applies and charges lubricating oil and grease on the inside is used, and a lubricant is such consisting of liquid and semi-solid ones provided with the specified revolution and heat resistance, therefore mineral oil, polyphenylether or the like are listed up as well. The formation of a thionic acid metallic salt coat on a bearing surface is carried out after it is dipped in a solution of thionic acid ether, and then grease and lubricating oil are applied and charged onto the frictional surface. As the abovementioned, even in such a boundary lubricating condition where an oil film is used up, sulfuric lubricating matter out of the coat is held on the frictional surface, enhancing its lubricity, and metals themselves will in no case come into contact with one another, and besides, there is less in each individual variation in a frictional characteristic, and thus bearing life is stabilized and it is prolongable for hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal material for a bearing used by liquid lubrication, a method for producing the same, and a rolling bearing.

[0002]

2. Description of the Related Art In general, a rolling bearing is constructed by assembling inner and outer races, rolling elements, retainers, seal members, etc. made of bearing steel or other metal. The agent is filled. For example, 10
Rolling bearings that require stable rotation performance under operating conditions of 10000 rpm at 0 to 150 ° C. are filled with grease or the like that has high-temperature, high-speed rotation and good lubrication characteristics.

[0003] Specific examples of the fluid lubricating lubricant to be filled in the rolling bearing include lubricating oils such as petroleum-based lubricants, synthetic lubricating oils, and lubricating greases containing a thickener added thereto. A lubricating grease using an alkyl diphenyl ether oil as a base oil and a diurea compound as a thickener has excellent durability especially at high temperatures and high speed rotation. In addition, the above-mentioned lubricant, antioxidant, extreme pressure agent, those added with various additives such as friction modifier,
It is a more preferred lubricant for rolling bearings with the properties of each additive.

When the conventional fluid lubricated rolling bearing as described above is used in a boundary lubrication state, an interfacial lubrication state in which an oil film does not exist partially or temporarily on its friction surface occurs, and heat is generated at that time. Accordingly, there is a problem that lubricants such as grease are deteriorated due to generation of wear powder due to sliding between metals, and the bearing life cannot be sufficiently extended.

As a rolling bearing for solving the above-mentioned problems, the applicant of the present application has disclosed in Japanese Patent Application Laid-Open No. 7-190073 a fluid-lubricated rolling bearing in which grease or lubricating oil is interposed on a friction surface of a metal rolling bearing. It has been disclosed that a metal phosphate coating can be formed on the friction surface of the bearing to enhance the ability to form an oil film and extend the life of the bearing.

[0006]

However, the above-described conventional rolling bearing has a large variation in its oil film forming ability and durability time even when a metal phosphate coating is formed on the friction surface under the same conditions, and is stable. There is a problem that it is difficult to obtain a rolling bearing of a high quality.

Accordingly, a first object of the present invention is to solve the above-mentioned problems, to improve the friction characteristics of a bearing metal material under boundary lubrication conditions, and to increase the temperature at a high temperature (eg, 120 ° C. or higher)
An object of the present invention is to provide a metal material for bearings that has little individual variation in frictional characteristics under a high-speed use condition and can stably extend the life of the bearing for a long time.

A second object of the present invention is to improve the friction characteristics of a sliding surface of a metal rolling bearing or a friction surface in rolling contact under boundary lubrication conditions, and rotate at a high temperature and a high speed as described above. An object of the present invention is to provide a long-life rolling bearing that can be rotated stably for a long time with little variation among products.

[0009]

Means for Solving the Problems In order to solve the above-mentioned first problem, in the present invention, a bearing metal material in which a metal thiophosphate salt film is formed on the surface of a bearing metal material is used. .

[0010] Alternatively, a means is employed in which a bearing metal material is immersed in a thiophosphate solution to form a metal thiophosphate salt coating on the surface of the bearing metal material to produce the bearing metal material.

In order to solve the second problem, the invention of the present application is a rolling bearing in which a metal thiophosphate metal salt film is formed on a sliding surface or a rolling surface of a metal rolling bearing. is there.

In the invention relating to the bearing metal material of the present application, since the metal thiophosphate coating is formed on the surface of the bearing metal material, even in a boundary lubrication condition in which an oil film is cut off on the friction surface of the bearing, Sulfur-based lubricating substances from the metal thiophosphate coating are retained on the friction surface to enhance lubricity, and there is no direct contact between metals, reducing individual variations in friction characteristics, and stabilizing the bearing life. Metal material for bearings that can be extended for a long time.

Further, in the rolling bearing of the present invention, since the metal thiophosphate coating is formed on the friction surface, the metal thiophosphate coating can be formed even under boundary lubrication conditions in which the oil film is cut off on the friction surface of the bearing. Sulfur-based lubricating substance is retained on the friction surface to improve lubricity, and there is no contact between metals, and individual variations in friction characteristics are reduced, that is, rolling that can prolong bearing life stably for a long time Become a bearing.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The bearing metal material used in the present invention is a well-known metal material that can be used for bearing components (inner / outer rings, rolling elements, cages, etc.), and in particular, the types of metal materials are limited. Not something. As a specific example, a bearing steel (high carbon chromium bearing steel JIS G480) is used as a material for a bearing ring.
5), case hardening steel (JIS G4104 etc.), high speed steel (A
MS6490), stainless steel (JIS G430)
3) and induction hardened steel (JIS G4051 etc.). As the material for the retainer, a steel plate for a punched retainer (J
IS G 3141), carbon steel for machined cage (J
IS G 4051) and a high-strength brass casting (JIS H 5102 etc.) for a machined cage. It is also possible to use a metal plate, white metal containing lead or tin, and other bearing alloys.

The rolling bearing in the present invention is not particularly limited in the form of a radial bearing, a thrust bearing and the like, but the inner and outer rings and the rolling elements are made of a metal capable of being treated with a thiophosphoric acid film. The retainer and the seal member may be made of not only metal but also plastic or ceramic.

In the present invention, the inside (gap) of the rolling bearing
Use a rolling bearing by liquid lubrication, in which lubricating oil or grease is applied or filled. The kind of the lubricant is not particularly limited as long as it is a liquid or semi-solid lubricant having a required rotation speed and heat resistance. Usable lubricating oils include, for example, mineral oil, polyphenyl ether, alkyl diphenyl ether, polyolefin and the like. In addition, grease obtained by adding a thickening agent such as metal soap or polyurea to such a lubricating oil as a base oil and increasing the thickness can also be used.

In order to form a metal thiophosphate coating on the above-mentioned metal bearing surface, the rolling bearing is immersed in a thiophosphate ester solution, and then the friction surface is coated or filled with grease or lubricating oil. As a typical example of the above-mentioned thiophosphoric acid ester, trithiophosphoric acid represented by the formula (RO) ₃ P = S (wherein R represents an aryl group, an aliphatic hydrocarbon group or an alicyclic hydrocarbon group). Esters are mentioned. Specific examples of the thiophosphoric acid triester include triphenyl thiophosphate (C ₆ H ₅ O) ₃ P） S.

When the above-mentioned bearing alloy is reacted with the thiophosphoric acid triester to form a metal phosphate film on the surface thereof, it is preferable to carry out the reaction while heating to increase the reaction speed.

[0019]

【Example】

[Example 1] 5 g of triphenyl thiophosphate (manufactured by Ciba-Geigy: Ilgarbe TPPT) was dissolved in 95 g of lubricating oil (manufactured by Matsumura Sekiyu KK: Moresco Hilube LB100), and a disc formed of bearing steel in this solution. A substrate (outer diameter 50 mm, inner diameter 8.1 mm, thickness 7 mm) was immersed and kept at 120 ° C. for 100 hours to form a film of iron thiophosphate or another metal thiophosphate on the disk substrate surface.

On one side of this disk substrate, 2 mg of lubricating oil (Shinfluid 601 manufactured by Nippon Steel Chemical Co., Ltd.) was uniformly applied, and a friction and wear test was conducted under the conditions shown in Table 1 below. The time (h) required until the friction coefficient reaches μ = 0.3 is shown in FIG.

[0021]

[Table 1]

[Comparative Example 1] A disk having no metal thiophosphate coating (the same as that used in Example 1) was used, and lubricating oil (Shinflud 601 manufactured by Nippon Steel Chemical Co., Ltd.) was applied to one surface of the disk. 2) was uniformly applied, and a friction and wear test was conducted under the conditions shown in Table 1 above. The results are also shown in FIG.

As is clear from the results of FIG. 1, the disk of Example 1 in which the metal thiophosphate coating was formed was 6 times more than the comparative example 1 in which the disk of the same material had no metal thiophosphate coating. A bearing life (hour) of up to 30 times was shown.

Example 2 5 g of triphenyl thiophosphate (manufactured by Ciba-Geigy: Ilgarbe TPPT) was lubricated with oil (Moleco LB100 manufactured by Matsumura Sekiyu KK)
5 g, and immerse bearing 6204 (radial ball bearing (single row deep groove ball bearing), bearing steel) from NTN Corporation in this solution, immersed at 120 ° C. for 100 hours, inner / outer ring, rolling element An iron thiophosphate or other metal thiophosphate metal salt film was formed on the surface of.

Next, 0.23-0.25 g of commercially available mineral oil-based grease (Nig Ace WR-S, manufactured by Nippon Grease Co., Ltd.) is filled in the rolling surface of this bearing, and a non-contact seal made of iron is attached to the side surface of the bearing. The life of the rolling bearing was examined by the following test method.

<< Durability Test of Rolling Bearing >> Three bearings of Example 2 were used, and a rotating shaft with a motor was attached to these inner rings to apply a thrust load of 6.8 kgf. Radial load 6.8kg
f, and the inner ring was rotated via a rotating shaft at a speed of 10,000 revolutions per minute in an atmosphere of 150 ° C. When the rotational torque of these bearings increases and the input current of the electric motor driving the rotating shaft exceeds the current limit (ie, when the rotational torque becomes twice or more the starting torque), the life of the rolling bearing is reduced. (Time: h), and the respective results are shown in the graph of FIG.

[Comparative Example 2] Mineral oil-based grease (Nig Ace WR-S, manufactured by Nippon Grease Co., Ltd.) was applied to the rolling surface of the bearing 6204 having no metal thiophosphate coating in the range of 0.23 to 0.23.
0.25 g was sealed, a non-contact seal made of iron was attached to the side surface of the bearing, and a durability test of the rolling bearing was performed in exactly the same manner and under the same conditions as in Example 2. The results are also shown in FIG.

Comparative Example 3 Tricresyl phosphate 7.36
g was diluted with 2-propanol to prepare 200 ml of a phosphoric acid triester solution, and this solution was used to add both bearings 6204 (made by NTN Corporation: radial ball bearings (single-row deep groove ball bearings), bearing steel) and rolling bearings. Moving body at solution temperature 60 ° C
For 2 hours to form a film of iron phosphate or other metal phosphate on the surface.

Next, 0.23-0.25 g of commercially available mineral oil-based grease (Nig Ace WR-S, manufactured by Nippon Grease Co., Ltd.) is filled in the rolling surface of the bearing, and a non-contact seal made of iron is attached to the side surface of the bearing. The durability (life time) of the rolling bearing was examined by the test method described above.

As is clear from the results shown in FIG. 2, in the embodiment 2 in which the metal thiophosphate coating was formed on the surfaces of the inner and outer rings of the bearing and the rolling elements, the metal thiophosphate coating was formed on the surface of the component. 6 to 24 times the life (hours) of the bearing compared to Comparative Example 2, which did not.

In the bearing life of the second embodiment, the difference between the shortest time and the longest time of the three test pieces is 290 hours, which is 1.7 times, which is a stable long-term bearing. Life was over. However, in the test piece of Comparative Example 3 in which the metal phosphate coating was formed, the difference between the shortest time and the longest time of the three test pieces was 550 hours, which was a 2.8-fold difference. The difference (variation) between the individual life times of the pieces was large.

[0032]

As described above, the invention of the present application in which a metal thiophosphate film is formed on the surface of a metal material for a bearing,
Even when used under boundary lubrication conditions, the bearing metal material is not exposed to the friction surface and maintains lubricity, preventing the generation of metal abrasion powder and preventing grease deterioration under high temperature and high speed use conditions There is an advantage that the bearing life of the rolling bearing is small, and there is little individual variation, and the bearing life is stable and long.

Further, the invention according to the manufacturing method for forming a metal thiophosphate coating on the surface of a metal material for a bearing improves the friction characteristics of the metal material for a bearing under boundary lubrication conditions, and allows the metal material for a bearing to be used at a high temperature and a high speed. Therefore, there is an advantage that a metal material for a bearing can be provided which has less individual variation in friction characteristics and can stably prolong the bearing life and extend for a long time.

Further, in the invention relating to the rolling bearing, since the metal thiophosphate salt coating is formed on the friction surface, the friction characteristics under boundary lubrication conditions are improved, and the rolling bearing which rotates at high temperature and high speed is manufactured. There are few individual variations,
There is an advantage that the rolling bearing has a long life and can rotate stably for a long time.

[Brief description of the drawings]

FIG. 1 is a table showing the results of friction and wear tests of Example 1 and Comparative Example 1.

FIG. 2 is a table showing results of endurance tests of Example 2 and Comparative Example 2.

FIG. 3 is a table showing the results of a durability test of Comparative Example 3.

Claims (4)

[Claims] 1. A bearing metal material formed by forming a metal thiophosphate salt coating on the surface of a bearing metal material. 2. A method for producing a bearing metal material, comprising immersing a bearing metal material in a thiophosphate ester solution and forming a metal thiophosphate salt coating on the surface of the bearing metal material. 3. The method according to claim 2, wherein the thiophosphate is triphenyl thiophosphate. 4. A rolling bearing having a metal thiophosphate metal salt film formed on a sliding surface or a rolling surface of a rolling contact made of a metal rolling bearing.