Magnetic disk storage apparatus and method for controlling magnetic disk storage apparatus
AssigneeHitachi, Ltd.
InventorsKenji Yoshida, Hiroshi Satou, Kenji Nishimura
Life of this patent
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Abstract
In a magnetic disk storage apparatus, when power supply is stopped, a magnetic head can be retracted safely and quickly so as not to be damaged. There are provided a back electromotive force detecting means that detects back electromotive forces developed in coils of a voice coil motor for moving a magnetic head when power supply is stopped, and a brake control means that judges a movement speed of the magnetic head from the detected back electromotive forces, and brakes the voice coil motor when the movement speed is greater than a preset first limited speed.
Claims10
A magnetic disk storage apparatus comprising:
- a first motor for rotating magnetic disk;
- a magnetic head for reading information from storage tracks on magnetic disk rotated by the first motor;
- a second motor for moving the magnetic head over the disk;
- and
- a second motor driving control circuit for controlling the movement of the magnetic head by controlling drive currents of the second motor,
- wherein there are provided a back electromotive force detecting means for detecting back electromotive forces developed in coils of the second motor when power supply is stopped, and a brake control means for judging a movement speed of the magnetic head from detected back electromotive forces and braking the second motor when the movement speed is greater than a preset first limited speed.
A magnetic disk storage apparatus comprising:
- a first motor for rotating magnetic disk;
- a magnetic head for reading information from storage tracks on magnetic disk rotated by the first motor;
- a second motor for moving the magnetic head over the disk;
- and
- a second motor driving control circuit for controlling the movement of the magnetic head by controlling drive currents of the second motor,
- wherein there are provided a back electromotive force detecting means for detecting back electromotive forces developed in coils of the second motor when power supply is stopped, and a brake control means for judging a movement speed of the magnetic head from detected back electromotive forces and braking the second motor when a movement speed in one direction is greater than a preset first limited speed and when greater than a second limited speed in a direction opposite to the one direction.
A method of controlling a magnetic disk storage apparatus comprising:
- a disk rotating motor for rotating magnetic disk;
- a magnetic head for reading information from storage tracks on magnetic disk rotated by the disk rotating motor;
- a head moving motor for rotating the magnetic head over the disk;
- and a head moving motor driving control circuit for controlling the movement of the magnetic head by controlling drive currents of the head moving motor,
- wherein the method comprises the steps of:
- detecting back electromotive forces developed in coils of the head moving motor when power supply is stopped;
- judging a movement speed of the magnetic head from the detected back electromotive forces;
- and
- braking the head moving motor when a movement speed in one direction is greater than a preset first limited speed and when greater than a second limited speed in a direction opposite to the one direction.
Dependencies are inferred from the claim text.