Rolling bearings and methods of producing the same

摘要

The present invention is directed to rolling type bearings having an enhanced resistance to acoustic performance degradation that are best suited for incorporation into information systems as well as methods of producing such rolling type bearings. The resistance to acoustic performance degradation is achieved by improving the microstructure of bearing steel to make it possible to prevent the formation of indentations which can result from prolonged exposure to high-temperature conditions, dropping or other impact loads. A rolling type bearing of the invention comprises outer and inner rings and rolling elements disposed therebetween, at least the outer and inner rings being made of a steel material whose microstructure consists essentially of a mixture of ferrite and cementite. The microstructure consisting essentially of the mixture of ferrite and cementite is produced by quenching or carbonitriding the steel material, and tempering it at a temperature higher than a third stage tempering temperature for steels.