| 摘要 |
PROBLEM TO BE SOLVED: To prevent the service life of grease from being affected by forming a chemical formation treated film on a raceway surface of an outer ring, specifying the film thickness, and specifying the concentration of calcium in the film relative to zinc to keep the rust-proof property and the galling preventive function. SOLUTION: A chemical formation treated film 8 is formed of manganese phosphate, zinc phosphate or calcium zinc phosphate on a surface of raceway surfaces 4, 5 of an inner ring 2 and an outer ring 3 of a bearing 1, and grease 6 is sealed with a seal member 7. The film thickness of the chemical formation treated film is >=1 μm to <=5 μm, and the concentration of calcium in the chemical formation treatment solution to be used in forming the thin film is >=0.4 to <0.8 to the concentration of zinc in the treatment solution. Spherical crystals are especially effective taking into consideration the crystalline shape in forming the thin film, and the time of durability is rapidly reduced when the film thickness exceeds 5 μm, while the time of durability is increased but the rust-proof property becomes inferior if the film thickness is <=1 μm. When the grain becomes coarse, the service life of grease is reduced. Thus, the rust-proof property and the galling preventive function are kept, and the service life of grease is not affected. |
