Patent ID: 7690846

Claim:
A bearing device comprising: a bearing ring; a shaft body having a cylindrical portion that is made of carbon steel including pearlite having a cementite layer structure, and the cylindrical portion having an end portion caulked onto the bearing ring; and said shaft body being processed to provide, at least in the end portion of the cylindrical portion of the shaft body, a lamella layer gap of the cementite in the pearlite made greater in thickness than a layer gap outside of the end portion, wherein the shaft body is processed such that a set of characteristics is provided in the end portion, wherein: the characteristics include: the end portion of the shaft body having an average value of the lamella layer gaps of the cementite in a range from 0.2 μm to not more than 0.35 μm, the carbon steel having a carbon content in a range from not less than 0.37% to not more than 0.65%, and the end portion of the shaft body having a hardness of in the range of 20 HRC down to but not less than 15 HRC.