| 摘要 |
PROBLEM TO BE SOLVED: To suppress a decrease in hardness even under a high temperature so as to maintain a long life, by specifying the ratio of a friction coefficient between an inner ring and a rolling body, to a friction coefficient between an outer ring and a rolling body; and an oil film parameter between the outer ring and the rolling body, to an oil film parameter between the inner ring and the rolling body. SOLUTION: Friction coefficient ratioμi/μo between an inner/outer ring and a rolling body is set larger than 0.8 less than 1.0, an oil film parameterΛ=hmin/(R1rms2+ R2rms2) is set to a region larger than 0.8 less than 4.0. Where, hmin represents a minimum oil film thickness, R1rms represents raceway surface root mean square roughness of a bearing ring, and R2rms represents raceway surface root means square. In a calculation example assuming Ra=0.1μm for roughness of the rolling body and outer ring relating to an automatic aligning rolling bearing ofϕ55 mm internal diameter, each practical example 1 to 4 is placed in a calculation range as shown. By applying surface treatment of carbonitriding or the like to an inner ring of large maximum contact bearing pressure, surface hardness is increased, a press dent generated in the bearing ring and the rolling body due to mixing of foreign matter can be small and shallowly suppressed, by decreasing wear even relating to surface damage fatigue, a long life is obtained relating to both fatigue.
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