Patent ID: 7391139
Filing Date: 2008-06-24
Classification: F16C,H02K

Abstract:
1. A spindle motor comprising a stationary member and a rotational member which is rotatable with respect to the stationary member via a radial bearing portion and a thrust bearing portion, wherein: the rotational member includes a shaft, and an outer cylindrical member and a rotor hub attached to the shaft, the outer cylindrical member being formed of an cylindrical portion and a collar portion extending from one end of the cylindrical portion in a direction perpendicular to an outer peripheral surface; the stationary member includes a sleeve member having an inner peripheral surface opposing an outer peripheral surface of the cylindrical portion of the outer cylindrical member in a radial direction, and an upper surface opposing a lower surface of the collar portion of the outer cylindrical member in an axial direction; the radial bearing portion is formed of a fluid between the outer peripheral surface of the cylindrical portion of the outer cylindrical member and the inner peripheral surface of the sleeve opposing it in the radial direction, and a dynamic pressure generating groove formed on at least one of the outer peripheral surface of the cylindrical portion of the outer cylindrical member and the inner peripheral surface of the sleeve; and the thrust bearing portion is formed of a fluid between the lower surface of the collar portion of the outer cylindrical member and the upper surface of the sleeve opposing it in the axial direction, and a dynamic pressure generating groove formed on at least one of the lower surface of the collar portion of the outer cylindrical member and the upper surface of the sleeve.