| 摘要 |
PROBLEM TO BE SOLVED: To suppress any abnormal discharge and electric damages by preventing the charge of a rotating body while maintaining long service life. SOLUTION: Electric conductivity is given between the inside of a bearing and an outer ring by containing, at least one of 20-60 wt.% nitride, carbide or boride of transition element in a ceramic material user for a bearing component while maintaining long durability by the ceramic material. The increase and distribution of the bearing vibration are suppressed by forming crystalline grains of silicon nitride of columnar crystals of the width of <=5 μm, and the bearing of long service life and high reliability can be obtained. At least one of 20-70 wt.% nitride, carbide or boride of the transition element is contained in the surface of the rolling element, and the strength is further improved by setting the inside content to be smaller than the surface. |
