Patent ID: 7687951

Claim:
A fluid dynamic bearing device, comprising: a shaft member; a cylindrical radial bearing surface forming a radial bearing gap with an outer peripheral surface of the shaft member; a bearing member formed by injection molding with an electroformed portion inserted, the electroformed portion having the radial bearing surface; and a thrust bearing portion equipped with a thrust bearing surface formed on an end surface of the bearing member and a thrust bearing gap facing the thrust bearing surface, wherein the shaft member is supported in a thrust direction by a dynamic pressure action of a lubricating fluid generated in the thrust bearing gap, wherein the electroformed portion is provided at the radial bearing surface thereof with a dynamic pressure generating portion for generating fluid pressure in the radial bearing gap, the dynamic pressure generating portion being formed by depositing a metal on a mold having a protrusion and a recess corresponding to the configuration of the dynamic pressure generating portion and separating the metal from the mold.