International Business Machines Corporation

David F Glaess

Thomas S Larson

Patricia Joanne Wadkins

Randall Mason Bates

Peter E Brooks

Disclosed is a disk drive having a spindle motor, a disk that is rotated by the spindle motor, and a movable actuator arm that carries a read/write head. The head physically engages a parked, or home, position at the Inner Diameter (ID) of the disk when the spindle motor is not energized and the disk is stationary. The electrical energization that must be applied to the spindle motor in order to breakaway the head from the disk (i.e., the breakaway current), and the energization that is necessary to cause the motor to achieve a stable spinning state (i.e., the spin current) are monitored. Possible future failure of the disk drive is predicted as a function of any changes in these two-electrical parameters, as these parameters may change over a period of time; i.e., may change over a number of disk drive stop/start events.

Method and apparatus for predicting failure of a disk drive

Disclosed is a disk drive having a spindle motor, a disk that is rotated by the spindle motor, and a movable actuator arm that carries a read/write head. The head physically engages a parked, or home, position at the Inner Diameter (ID) of the disk when the spindle motor is not energized and the disk is stationary. The electrical energization that must be applied to the spindle motor in order to breakaway the head from the disk (i.e., the breakaway current), and the energization that is necessary to cause the motor to achieve a stable spinning state (i.e., the spin current) are monitored. Possible future failure of the disk drive is predicted as a function of any changes in these two electrical parameters, as these parameters may change over a period of time; i.e., may change over a number of disk drive stop/start events.

A clamp ring for clamping disks to a rotating hub includes a inner diameter leg portion, a cross member portion and a disk contacting portion. A cross sectional view of the clamp ring is N-shaped. The clamp ring is heated so that it thermally expands to a diameter that is larger than the outer diameter of the hub. A thermally expanded clamp ring is placed on the top of the disk stack which has at least one disk. An axial load is placed on the inner diameter leg portion as the clamp ring cools. The inner diameter grips the hub as it cools. The cross member is compressed as the clamp ring cools. The disk contacting portion moves slightly as the clamp ring cools. This movement counteracts the outward movement of the disk contacting portion of the clamp during loading resulting in little tendency to cone the disk. The result is a disk stack clamped without a resulting radial load on the disks.

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Rochester, MN, United States of America

David F Glaess