Rolling bearing
AssigneeNsk Ltd.
InventorsHiromichi Takemura, Yasuo Murakami
Life of this patent
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Abstract
An inner ring 3 of the rolling bearing is formed by a steel material having the following composition. This steel material contains as alloying constituents C, Si, Mn and Cr in an amount of from 0.65 to 1.20% by weight, from 0.10 to 0.70% by weight, from 0.20 to 1.20% by weight and from 0.20 to 1.80% by weight, respectively, and has an oxygen content of not more than 16 ppm. The content of retained austenite left after heat treatment is from 0 to 6% by volume and the surface hardness HRC of the bearing surface is from not less than 57 to not more than 65. Accordingly, it is possible to drastically prolong the lifetime of a rolling bearing operating under high vibration and load such as bearing for alternator.
Claims10
A rolling bearing comprising:
- a stationary race;
- a rotating race;
- and
- a plurality of rolling elements provided between said stationary race and said rotating race and lubricated with a grease,
- wherein at least one of the rotating race and the stationary race is made of a steel material containing:
- 0.65 to 1.20% by weight of C;
- 0.10 to 0.70% by weight of Si;
- 0.20 to 1.20% by weight of Mn;
- and
- 0.20 to 1.80% by weight of Cr,
- wherein said steel material further comprises an oxygen content of not more than 16 ppm, and
- wherein a content of retained austenite of said rotating race after subjecting to a heat treatment is from 0 to 6% by volume, and wherein a content of retained austenite of said stationary race is not less than 7% by volume after subjecting to a heat treatment.
Dependencies are inferred from the claim text.