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US 4,197,489 AGranted
Spindle drive system
AssigneeMFE Corporation
InventorsDavid S. Dunn, Fernando M. Vasconselos
Life of this patent
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Abstract
A floppy disk drive system employs an inside-out DC motor whose centrally located stator is mounted directly to the chassis. The motor has a tubular rotor that encircles the stator and it is supported co-axially with the stator by the rotary disk drive spindle. A timing and commutation disk is mounted directly on the rotor and, together with speed control and commutation networks, maintains uniform motor speed.
Claims5
A disk drive system comprising
- A. a chassis,
- B. a generally cylindrical brushless DC motor stator secured to the chassis,
- C. a tubular brushless DC motor rotor, said rotor having an inside diameter slightly greater than the diameter of the stator,
- D. a spindle secured to one end of the rotor co-axially with the rotor,
- E. means for rotatively supporting the spindle from the chassis so that the rotor envelops the stator and is co-axial therewith, and
- F. means for controlling the speed of said motor, said controlling means including
- (1) means extending around the perimeter of the rotor defining a timing track,
- (2) sensing means positioned adjacent the timing track for producing an electrical signal indicating the angular speed of the rotor relative to the sensing means,
- (3) means for generating a speed reference signal,
- (4) means for comparing said speed signal and said reference signal to develop an error signal indicating the deviation of the rotor speed from the reference speed, and
- (5) means responsive to the error signal for controlling the current to said stator so as to regulate the speed of the rotor to minimize said error signal.
8 more elements
Dependencies are inferred from the claim text.