Patent ID: 9051653
Filing Date: 2015-06-09
Classification: C23C,F16C

Abstract:
1. A rolling bearing comprising: an inner ring having a raceway on an outer circumferential surface thereof, an outer ring having a raceway on an inner circumferential surface hereof, a plurality of rolling elements which roll between said raceway of said inner ring and said raceway of said outer ring, and a cage retaining said rolling elements, wherein at least one bearing member selected from among said inner ring, said outer ring, said rolling elements, and said cage is made of an iron-based material, wherein said bearing member made of said iron-based material has a curved surface, a hard film is formed on said curved surface, said curved surface is at least one curved surface selected from among said raceway of said inner ring, said raceway of said outer ring, said rolling contact surfaces of said rolling elements, and a sliding contact surface of said cage, wherein said hard film is composed of a foundation layer, composed mainly of chromium, which is formed directly on said curved surface; a mixed layer, composed mainly of tungsten carbide and diamond-like carbon, which is formed on said foundation layer; and a surface layer, composed mainly of said diamond-like carbon, which is formed on said mixed layer, wherein said surface layer has a gradient layer part, disposed at a side adjacent to said mixed layer, said gradient layer part having a structure, in which a structure ratio between a graphite structure and a diamond structure in said diamond-like carbon of said gradient layer part, which inclines toward the diamond structure as a distance from said mixed layer increases, thus said gradient layer part being formed so that hardness of said gradient layer part becomes higher continuously or stepwise from said mixed layer and wherein a content rate of said tungsten carbide in said mixed layer becomes lower continuously or stepwise in a direction from a side of said foundation layer toward a side of said surface layer, and a content rate of said diamond-like carbon in said mixed layer becomes higher continuously or stepwise in said direction.