Patent ID: 6781268
Filing Date: 2004-08-24
Classification: F16C,G11B,H02K

Abstract:
A spindle motor comprising:a shaft; a sleeve formed with a through-hole fox rotary-play insertion of said shaft; a rotor having a round top plate in the rotational center of which said shaft is constituted integrally, and a circular cylindrical wall depending from said top plate, said rotor cylindrical wall having along its inner circumferential surface an inclined face sloping so that the inner diameter of said wall contracts with further separation from said rotor top plate; a radial bearing section configured by an oil-retaining micro-gap being formed in between an inner circumferential surface of said sleeve and an outer circumferential surface of said shaft, and by dynamic-pressure-generating grooves being provided for inducing, in response to said rotor spinning, fluid dynamic pressure in the oil retained in the micro-gap; a thrust bearing section configured by an oil-retaining micro-gap being formed in between an upper-end face of said sleeve and a bottom face of said top plate, and by dynamic-pressure-generating grooves being provided for inducing, in response to said rotor spinning, fluid dynamic pressure in the oil retained in the micro-gap; and a taper-seal area formed sloping from radially outward heading inward with respect to the rotational center axis, in between said inner circumferential surface of said rotor cylindrical wall and an outer circumferential surface of said sleeve, in a gap whose inter-surface dimension gradually flares with further separation from said rotor top plate, wherein a boundary surface of the oil forms within said taper-seal area.