Patent ID: 6316857
Filing Date: 2001-11-13
Classification: F16C,H02K

Abstract:
A spindle motor comprising:a base plate;a sleeve that is joined with said base plate, said sleeve is hollowed through vertically, the interior of the sleeve is widened at a bottom part so that said interior is stepwise difference;a stator assembly is joined to an outer surface of said sleeve above said base plate;a shaft inserted in said sleeve so that said shaft can revolve and is integral with a flange-shaped thrust at a bottom part coinciding with the interior where said sleeve interior has been widened;a rotor assembly with a hub center part joined to a top part of said shaft and a magnet attached at an inner cylindrical surface that is an outer cylindrical edge of said hub extended downward, the magnet generates electro-magnetic force by interaction with said stator assembly;a set of pressure-generating grooves that generate fluid kinetic pressure in a radial direction of the shaft, the grooves are respectively formed at upper and lower parts of the interior of said sleeve opposing the outer surface of said shaft; andanother set of pressure-generating grooves that generate fluid kinetic pressure in an axial direction, the grooves are respectively formed at a top surface of the base plate that is opposite a bottom surface of said thrust within said stepwise difference interior of said sleeve.