Bearing for main spindle of machine tool
AssigneeNtn Corporation
InventorsHiroshi Tako, Mamoru Mizutani
Life of this patent
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Abstract
A bearing for use in the main spindle of a machine tool is provide, in which at least the raceway of the bearing contains by mass, C: 0.6-1.3%, Si: 0.3—3.0%, Mn: 0.2-.5%, P: 0.03% or less, S: 0.03% or less, Cr: 0.3-5.0%, Ni: 0.1-3.0%, Al: 0.050% or less, Ti: 0.003% or less, O: 0.0015% or less, N: 0.015% or less; and the rest is composed of Fe and unavoidable impurities. The raceway is tempered after either quenching or carbonitriding and its surface hardness presents at least HRC 58 after tempering.
Claims12
A bearing for use in a main spindle of a machine tool, wherein at least a raceway of said bearing is made of steel comprising alloy elements by mass:
- C:
- no less than 0.6% and not more than 1.3%;
- Si:
- no less than 0.5% and not more than 3.0%;
- Mn:
- no less than 0.2% and not more than 1.5%;
- P:
- no less than 0.016% and no more than 0.03%;
- S:
- no less than 0.017% and no more than 0.03%;
- Cr:
- no less than 0.3% and not more than 5.0%;
- Ni:
- no less than 0.5% and not more than 3.0%;
- Al:
- no less than 0.020% and no more than 0.050%;
- Ti:
- no less than 0.0022% and no more than 0.003%;
- O:
- no less than 0.0009% and no more than 0.0015%;
- N:
- no less than 0.008% and no more than 0.015%;
- Fe and unavoidable impurities, and
- wherein said raceway is tempered after either quenching or carbonitriding and its surface hardness presents at least HRC 58 after tempering.
Dependencies are inferred from the claim text.