Patent ID: 7201517

Claim:
A hydrodynamic bearing device comprising: a hydrodynamic bearing member that uses dynamic pressure generated by pressurizing lubricant fluid with a dynamic pressure generating means to support a rotary shaft in a non-contact manner; two radial hydrodynamic bearing portions, spaced in the axial direction, being provided in a portion of the area created between a radially opposing inner circumferential wall of said hydrodynamic bearing member and an outer circumferential wall of said rotary shaft; a thrust hydrodynamic bearing portion being provided in a portion of the area created in the thrust direction between the axial end surface of a rotary member that rotates together with said rotary shaft and the axial end surface of said hydrodynamic bearing member; said lubricant fluid being projected in a bearing space without interruption, said bearing space being formed to be continuous from said radial hydrodynamic bearing portions at two positions to said thrust hydrodynamic bearing portion; wherein said bearing space from one of said two radial hydrodynamic bearing portions, which is adjacent to said thrust hydrodynamic bearing portion, to said thrust hydrodynamic bearing portion capable of communicating with an axially outside space, which is adjacent to the other radial hydrodynamic bearing portion, through a pressure-adjusting bypass created separately from said bearing space; a fluid reservoir, which is configured by the gap space created by enlarging said bearing space of said radial hydrodynamic bearing portion in the radial direction, being provided in said bearing space between said two radial hydrodynamic bearing portions; and wherein pumping power is applied to said lubricant fluid in said two radial hydrodynamic bearing portions maintaining said lubricant fluid in said fluid reservoir at a positive pressure, which is greater than the atmospheric pressure.