Patent ID: 8256962

Claim:
A fluid dynamic bearing device comprising: a shaft member; a bearing member in an inner periphery of which the shaft member is inserted, which has on an outer peripheral surface thereof a fixing surface for fixation to a bracket, which is formed as an integral member including a sleeve portion and protruding portions arranged on both sides in an axial direction of the sleeve portion and having inner peripheral surfaces with diameters larger than that of the inner peripheral surface of the sleeve portion, and which is open at both axial ends; a cover member which is fixed to an inner periphery of one protruding portion; a radial bearing portion radially supporting the shaft member by a dynamic pressure action of a lubricant fluid generated in a radial bearing gap between an outer peripheral surface of the shaft member and an inner peripheral surface of the sleeve portion; a thrust bearing portion which comprises a thrust bearing gap facing an axial end surface of the sleeve portion, and which supports the shaft member in a thrust direction by a dynamic pressure action of a lubricant fluid generated in the thrust bearing gap; a dynamic pressure generating portion which is formed by molding in the inner peripheral surface of the sleeve portion and which generates the dynamic pressure action of the lubricant fluid in the radial bearing gap; a seal member arranged in an inner periphery of the other protruding portion and forming a seal space; and a fluid flow path which has a portion open at both axial end surfaces of the sleeve portion of bearing member and through which the lubricant fluid flows between the thrust bearing gap of the thrust bearing portion and the seal space.