| 摘要 |
PROBLEM TO BE SOLVED: To provide a shaft having a surface that functions as a raceway surface of an inner ring of a rolling bearing, such as a pinion shaft of a planetary gear device, which has adequate rolling fatigue characteristics under such a harsh environment as to deteriorate a capability of forming an oil film and is hard to cause heat deformation (plastic bending). SOLUTION: The pinion shaft 5 is obtained by using a material of a predetermined alloy steel and subjecting the material to carburizing or carbonitriding treatment, quenching treatment, sub-zero treatment and tempering treatment at 150 to 200°C. Then, the shaft contains 0.8 to 2.0 mass% in total of carbon and nitrogen on the surface, has the surface hardness of 700 to 900 by Vickers hardness (Hv), contains 20 to 50 vol% of retained austenite on the surface, and contains no retained austenite in the core portion. COPYRIGHT: (C)2010,JPO&INPIT |
