Patent ID: 7300209

Claim:
An aerodynamic bearing assembly employed in a spindle motor for hard disk drives, the spindle motor including a base, a hub, a stator and a permanent magnet, the base serving as a lower portion of the spindle motor, the hub being rotatably fitted on the base and able to fixedly mount a platter, the stator being formed with a plurality of cores wound around by at least one coil along an outer circumference of the stator and being formed with an open press-fit portion at a center of the stator, the permanent magnet being fitted on an inner circumferential surface of the hub and generating a magnetic field in cooperation with the coil, the aerodynamic bearing assembly comprising: an aerodynamic bearing including a main bearing body formed in a concentric disk shape to serve as an upper portion of the aerodynamic bearing, and an auxiliary bearing body integrally formed on a lower portion of the main bearing body and press-fitted into an open press-fit portion of the stator to fixedly mount the stator on an outer circumferential surface of the auxiliary bearing body, the aerodynamic bearing being fixedly installed in a space between the base and the hub; and a ball bearing for rotatably supporting a center of the hub in both radial and thrust directions at a rotational center of the aerodynamic bearing, wherein at least one of an upper horizontal surface of the main bearing body of the aerodynamic bearing, an outer circumferential surface of the main bearing body of the aerodynamic bearing, a lower horizontal surface of the hub and a lower inner circumferential surface of the hub, is provided with at least one air groove having a predetermined depth, the air groove generating aerodynamic pressure between the hub and the aerodynamic bearing while the hub rotates.