US Patent 7511920 Hard disk and spindle motor assembly

A spindle motor assembly includes a spindle motor having a shaft and a hub that rotates on the shaft, and a hard disk having a data storage medium mounted in the form of a whole disk, and a fastener attached to the center of a bottom surface of the disk-shaped data storage medium that faces the spindle motor. The fastener is a screw or a nut. In the case in which the fastener is a screw, a head of the screw is attached to the bottom surface of the hard disk, and the body of the screw is received in a screw hole in the upper portion of the shaft of the spindle motor. In the case in which the fastener is a nut, the nut is engaged with an external thread on an outer circumferential surface of the hub of the spindle motor.