| 摘要 |
PURPOSE:To raise oil film forming capacity even when water is present in lubricating oil and to prevent the generation of peeling damage by forming independent, fine, concave recesses on the rolling contact surface of ball-and- roller bearing. CONSTITUTION:Surface roughness RMS(L) in the axial direction/surface roughness RMS(C) in the circumferential direction is not more than 1.0 and both Sk values as a parameter of surface roughness in the axial direction and circumferential direction are made so as to become negative. Further, by making the surface area ratio that is shown by fine recesses 10-40% and the average area 35-150mum<2> when arranging by omitting the diameter of equivalent circle of not more than 3mumphi, the oil film forming rate of rolling contact surface is improved and, even when water is present in lubricating oil, peeling damage is not generated on the rolling contact surface and long life can be obtained. |
