Patent ID: 8304946
Filing Date: 2012-11-06
Classification: F16C

Abstract:
1. A spindle motor, comprising: a stationary support shaft perpendicularly fastened to a base plate; a thrust plate fitted over the stationary support shaft at a position adjacent to the base plate; a sleeve fitted over the stationary support shaft so as to be rotatable, the sleeve being coupled to a rotor casing, onto which a magnetic disk is seated, the rotor casing surrounding a circumferential outer surface of the sleeve; an annular stopper fastened to the sleeve or the rotor casing to support a lower surface of the thrust plate and prevent the sleeve from being removed from the stationary support shaft, the stopper forming a first fluid sealing part between the stopper and the thrust plate; and an annular sealing cap coupled to the sleeve or the rotor casing to store fluid between the sealing cap and an upper surface of the sleeve and form a second fluid sealing part between the sealing cap and the stationary support shaft, wherein the sleeve has therein a fluid circulation hole, through which the fluid, pumped by a first and second radial bearing, using dynamic pressure between the sleeve and the stationary support shaft, is moved to the first and second radial bearing via the sealing cap such that the fluid circulates around the sleeve.