Rolling bearing
OwnerShigeru Okita, Susumu Tanaka +1inventors
InventorsShigeru Okita, Susumu Tanaka, Tomonobu Yoshikawa
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Abstract
An inner ring and an outer ring are composed as follows. These members are fabricated with a steel for bearing containing carbon 0.6 wt % or higher. A carbonitrided layer is formed in a raceway surface. The amount of residual austenite at a position of 2% Da depth in the raceway surface is determined to be 1.0 vol % or lower. Hardness at the position of 2% Da depth is set to be HRC58 or more. Nitrogen content (Np) at the position of 2% Da depth is 0.05 wt % or more. A multiple Gd of an impression resistance expressed with the following formula (1) is 1.6 or more, Gd=(H0.2/500)+2·Np (1), wherein in the formula, H0.2 is meant by Vickers hardness at the position of 2% Da depth.
Claims8
A rolling bearing including an outer ring having an outer raceway surface, at least one of an inner ring having an inner raceway surface and a shaft integrally formed with an inner raceway surface, and a plurality of rolling elements rotatably disposed between said outer raceway surface and said inner raceway surface,
- wherein, of the inner ring and the outer ring, at least said inner ring is fabricated with a bearing steel containing a carbon content of 0.6 wt % or more,
- at least said inner raceway surface has a carbonitrided layer, and
- in at least said inner ring, a multiple Gd of an impression resistance expressed with the following formula (1) is 1.6 or more,
- Gd=(H0.2/500)+2·Np (1),
- wherein NP is a nitrogen content (wt %) at a position of 2% Da depth which is located from the raceway surface to the side of a core portion by the amount of a dimension corresponding to 2% of the diameter of the rolling element and
- H0.2 is a Vickers hardness (Hv) at the position of 2% Da depth.
Dependencies are inferred from the claim text.