Disc clamp adjustment using heat

Details Disc clamp adjustment using heat Disc clamp adjustment using heat

2002-08-26

2004-03-09

Elve, M. Alexandra (Department: 1725)

Electric heating

Metal heating

By arc

Reexamination Certificate

active

06703584

ABSTRACT:

FIELD OF THE INVENTION
This application relates generally to disc drives and more particularly to a method and system for using heat to adjust a disc clamp of a disc drive.
BACKGROUND OF THE INVENTION
A disc drive typically includes one or more discs that are rotated at a constant high speed by a spindle motor during operation of the drive. Information is written to and read from tracks on the discs through the use of an actuator assembly, which rotates during a seek operation. A typical actuator assembly includes a plurality of actuator arms, which extend towards the discs, with one or more flexures extending from each of the actuator arms. Mounted at the distal end of each of the flexures is a head, which acts as an air bearing slider enabling the head to fly in close proximity above the corresponding surface of the associated disc.
Increasing the density of information stored on discs can increase the storage capacity of hard disc drives. To read the densely stored information, designers have decreased the gap fly height between the heads and the discs. Reducing the gap fly height can lead to increased contact between the head and the data portion of the disc during operation of the disc drive (i.e., head-disc interference). Such interference can excite head and disc resonance frequencies, which can interfere with the servo positioning of the recording heads over the data tracks. For example, if head-disc interference occurs during a servo track writing operation, then spurious vibrations may be written into the servo pattern due to the excitation of head and disc resonance modes. Head-disc interference can also lead to accelerated head and disc surface wear. This may culminate in a “head crash,” a phenomena where the recording head irreparably damages the disc surface, resulting in loss of data and catastrophic disc drive failure.
Head-disc interference is particularly likely if the disc surfaces are not sufficiently flat. Even if discs are flat before being mounted on the spindle motor, the disc clamp that secures the discs to the spindle motor may deform the discs by applying uneven pressure to the discs.
Accordingly there is a need for a disc clamp that more evenly distributes clamping pressure applied to the discs. The present invention provides a solution to this and other problems, and offers other advantages over the prior art.
SUMMARY OF THE INVENTION
Against this backdrop the present invention has been developed. An embodiment of the present invention is a method of adjusting a distribution of clamping pressure applied to a disc by a disc clamp. The method includes identifying the uneven distribution of clamping. A quantity of heat is determined and applied to the disc clamp so that the quantity of heat will remedy the uneven distribution of clamping pressure.
An alternative embodiment of the present invention is a method of adjusting a distribution of clamping pressure applied to a data storage disc by a disc clamp. This method includes analyzing a contour of a data surface of the disc and identifying from the contour an uneven distribution of clamping pressure applied to the disc by the disc clamp. A quantity of heat to be applied to the disc clamp to remedy the uneven distribution of clamping pressure is determined and applied to the disc clamp. Yet another embodiment of the present invention is a system for adjusting a clamping pressure applied to a data storage disc by a disc clamp. The system includes a disc pack assembly having a disc clamp securing a disc to a spindle motor hub. The system also includes means for identifying an uneven distribution of clamping pressure applied to the disc by the disc clamp and for remedying the uneven distribution of clamping pressure by heating the disc clamp for a period of time.


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