JP2009191280A5 - - Google Patents

Description

Further, Patent Document 3 discloses a high carbon chromium bearing steel containing Mn of 0.9 to 2.0% in order to improve the rolling fatigue life of mechanical parts such as ball screw parts and one-way clutch parts. A technology is described in which a manufactured material is tempered at 850 to 890 ° C. and then tempered to a temperature of 250 ° C. or less to obtain a surface hardness of 60 to 64 HRC, a residual austenite amount of 20 to 30%, and a prior austenite grain size of 9 or more. Has been. Since Mn lowers the Ms point, it is effective in securing retained austenite, but increasing the amount of Mn, which is a relatively expensive element, leads to an increase in the manufacturing cost of the part, and is applied to roller bearings. Moreover, it becomes a cause which raises the manufacturing cost of a roller bearing. In addition, when the quenching treatment of the component parts of the roller bearing is performed by soaking, which can be performed easily and at low cost, and the amount of retained austenite of the part is to be secured, the dimensional stability of the part deteriorates. there is a possibility.
Other publications that describe techniques for ensuring a rolling fatigue life under a foreign matter-mixed lubricating environment are known as described in Patent Documents 4 to 6, but have similar problems.

1a, 1b, 1c Radial roller bearings 2a, 2b, 2c Thrust roller bearings 3, 3a, 3b Rollers
4a, 4b, 4c cage
5a, 5b, 5c cage
6 shells
7, 7b, 7c Thrust raceway ring 8 Inner ring 9 Rotating shaft 10 Outer ring