Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Disk record
Reexamination Certificate
2001-06-28
2004-05-25
Heinz, A. J. (Department: 2653)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Disk record
Reexamination Certificate
active
06741420
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a spindle motor, and more particularly to a hydrodynamic spindle motor with a hydrodynamic heating element.
BACKGROUND OF THE INVENTION
Hydrodynamic spindle motors include a spindle hub rotatably coupled to a stationary spindle portion through a hydrodynamic interface. The spindle hub rotates relative to the stationary spindle portion by operation of a motor coupled to the stationary spindle portion and the spindle hub. Hydrodynamic spindle motors are used in some applications to rotate a disc stack for operation of a disc drive. Discs are stacked on the spindle hub for co-rotation. For operation, power is supplied to the motor to rotate the spindle hub. Sufficient power must be supplied to overcome drag or friction between the hydrodynamic fluid and the rotating components. During idle periods, such as during a power save mode, or when the disc drive is powered “off”, the temperature of the hydrodynamic fluid can drop, increasing viscosity of the fluid. This is especially true at extreme operating temperature ranges. This increased viscosity of the hydrodynamic fluid increases power required to initiate rotation and rotate the spindle motor “up to speed” for operation of the disc drive. Embodiments of this invention address these and other features and provides advantages not previously recognized nor appreciated in the prior art.
SUMMARY OF THE INVENTION
The present invention relates generally to a hydrodynamic spindle motor including an internally disposed heating element in a stationary spindle portion having a spindle hub rotatably coupled thereto. The hydrodynamic spindle motor has particular application for supporting discs for co-rotation for a disc drive. The heating element is activated to control viscosity of a hydrodynamic fluid of a hydrodynamic bearing rotationally supporting the spindle hub relative to the stationary spindle portion. These and various other features as well as advantages which characterize embodiments of the present invention will be apparent upon reading the following detailed description and review of the associated drawings.
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Elsing John
Jennings David J.
Castro Angel
Heinz A. J.
Seagate Technology LLC
Westman Champlin & Kelly P.A.
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