Disk centering method and apparatus for centering disks for disk drives

A method of centering a disk on the rotational axis of a motor, the motor including a hub, the disk having an outer diameter and an inner diameter, defining a center hole, comprising the sequential steps of:

• (a) loosely fixing the disk to the hub so that a portion of the hub protrudes into the center hole of the disk;
• (b) placing a contact element in contact with the outer diameter of the disk;
• (c) moving the contact element towards the rotational axis of the motor until a portion of the edge of the center hole of the disk contacts the protruding portion of the hub;
• (d) simultaneously rotating the disk and the hub and moving the contact element away from the rotational axis of the motor until the rotating element no longer contacts the disk, thereby centering the disk on the rotational axis of the motor;
• and
• (e) securely fixing the disk to the support surface of the hub.

A method of centering a disk on the rotational axis of a motor, the motor including a hub having a disk support surface, the disk having an outer diameter and an inner diameter, the inner diameter defining a center hole, comprising the sequential steps of:

• (a) loosely fixing the disk to the support surface of the hub so that a portion of the hub protrudes into the center hole of the disk;
• (b) placing a rotating element in contact with the outer diameter of the disk;
• (c) moving the rotating element towards the rotational axis of the motor after said step (b) until a portion of the edge of the center hole of the disk contacts the protruding portion of the hub;
• (d) simultaneously rotating the disk and the hub and gradually increasing the distance between the rotating element and the rotational axis of the motor at a linear rate of R inches per revolution, where R is approximately equal to or less than the desired runout of the outer diameter of the disk, until the rotating element no longer contacts the disk;
• and
• (e) securely fixing the disk to the support surface of the hub.

An apparatus for centering a disk on the rotational axis of a motor mounted to the base plate of a disk drive, the motor including a hub, the disk having an outer diameter and an inner diameter defining a center hole, comprising:

• first means for locating and supporting the base plate and the motor;
• second means for contacting the outer diameter of the disk;
• third means, provided on said first means, for rotating the motor and the hub at a selected rotational velocity;
• and
• fourth means, provided on said first means, for moving said second means toward the rotational axis of the motor until the inner diameter of the disk contacts the hub and for moving said second means away from the rotational axis of the motor at a rate related to the rotational velocity of the disk.

An apparatus for centering a disk on the rotational axis of a motor mounted to the base of a disk drive, the motor including a hub, the disk having an outer diameter and an inner diameter defining a center hole, comprising:

• first means for locating and supporting the base plate and the motor;
• second means for contacting the outer diameter of the disk;
• a drive unit;
• a drive head rotated by said drive unit;
• a drive arm, having said drive head mounted thereon, for rotating the hub and the disk, said drive arm being attached to said first means so that said drive arm moves between a position where said drive head engages the hub and a position where said drive head is disengaged from the hub;
• and
• third means, provided on said first means and mechanically connected to said drive unit, for moving said first means towards the rotational axis of the motor until the inner diameter of the disk contacts the hub and for moving said second means away from the rotational axis of the motor at a rate of R inches per revolution of the hub and disk, where R is approximately equal to or less than the desired runout of the outer diameter of the disk.