Patent ID: 8381404

Claim:
A method of manufacturing a fluid dynamic bearing in which, by supporting a bearing base material having, at its center, a housing hole portion for a shaft capable of relative rotation and by rotating the bearing base material around the central axis thereof, the inner surface of the housing hole portion is cut with a cutting tool to form a dynamic pressure groove including a folded portion that defines a fluid discharging side, the method comprising: forming a substantially linear groove having a length corresponding to a circumferential direction width of the dynamic pressure groove formed on the inner circumferential surface of the housing hole portion, along the circumferential direction of a surface orthogonal to a first processing direction along the central axis of the bearing base material, by the cutting tool that performs a micro alternating drive in a second processing direction orthogonal to the first processing direction, said forming of a substantially linear groove comprising progressively decreasing the groove depth of the linear groove corresponding to an area of the folded portion toward the fluid discharging side, and comprising forming the substantially linear groove to have a uniform depth in areas other than the area of the folded portion; and extending the dynamic pressure groove that extends in the first processing direction by continuously forming the substantially linear grooves in the first processing direction by displacing the relative positions of the bearing base material and the cutting tool in the first processing direction.