Patent ID: 6404087
Filing Date: 2002-06-11
Classification: F16C,H02K

Abstract:
A motor comprising:a shaft; a pair of disk-shaped thrust plates attached proximate either end of said shaft, said pair of thrust plates therein having mutually opposing axially inward faces; a sleeve having a radially inner peripheral surface opposing said shaft on its outer circumferential surface via radial micro-gaps, thrust faces opposing the axially inward faces of said pair of thrust plates via thrust micro-gaps, and inner peripheral surfaces radially opposing outer circumferential surfaces of said pair of thrust plates via gaps therewith; a pair of thrust dynamic-pressure bearing portions formed retaining a lubricant within said thrust micro-gaps, being defined in between the axially inward faces of said pair of thrust plates and the thrust faces of said sleeve by which they are axially opposed, wherein the lubricant retained in said thrust micro-gaps fronts on air within the gaps defined in between said thrust plate outer circumferential surfaces and said sleeve inner peripheral surfaces; a pair of radial dynamic-pressure bearing portions adjoining the pair of thrust dynamic-pressure bearing portions, wherein lubricant is retained, continuously with lubricant retained in said thrust dynamic-pressure bearing portions, within said micro-gap defined in between the outer circumferential surface of said shaft and the radially inner peripheral surface of said sleeve, wherein an annular gas intervention retaining air is provided approximately midway of said radial micro-gaps, meanwhile lubricant retained respectively in said pair of radial dynamic-pressure bearing portions fronts on air retained in the gas intervention, and the pairs of thrust dynamic-pressure bearing portions and radial dynamic-pressure bearing portions continuously retaining said lubricant are respectively configured as a first dynamic-pressure bearing section and a second dynamic-pressure bearing sections meanwhile all edges of the lubricant retained in the dynamic-pressure bearing sections form meniscuses due to balancing of surface tension of and intermolecular forces in said lubricant, and air pressure and surface energy of components the edges of the lubricant contact; and at least one communicating axial pathway formed in said sleeve, said axial pathway axially inter-penetrating said thrust faces configuring said pair of thrust dynamic-pressure bearing portions, wherein lubricant is retained continuously in said pair of thrust dynamic-pressure bearing portions, wherein lubricant shifts mutually through said communicating pathway between said first dynamic-pressure bearing section and second dynamic-pressure bearing section so as to make radii of curvature of the meniscuses formed at the edges of the lubricant retained in the dynamic-pressure bearing sections equal.