Patent ID: RE38772

Claim:
A disk memory drive comprising: a brushless drive motor having an internal space defined therein and a stator including winding means defining magnetically active parts of the drive motor and having a given axial extension, the motor having an outer rotor with an inner circumference, an outer circumference and an open end coaxially encircling the stator and a substantially cylindrical air gap defined between the stator and the rotor, the rotor including a separate non ferromagnetic hub and a soft iron ring element interiorly of said hub and radially located means forming a permanent magnet interiorly of said ring having a predetermined axial extension fixedly connected therewith for magnetic interaction with said winding means; a disk mounting section provided on the outside of said hub for accommodating at least one storage disk for location in a clean chamber surrounding said rotor when the drive motor is mounted for operation, the disk mounting section on the hub along its axial length being adapted to extend through a central aperture of the storage disk, the winding means and the magnet means interacting therewith being disposed for at least half of the axial extension thereof within a space surrounded by the disk mounting section of the hub; and first and second axially separated bearing means having inner and outer races on a shaft rotatably mounting the rotor and the hub on the shaft, the motor also including rotating means interacting with stationary means for determining the rotational position of the rotor, the internal space of said motor, which includes the internal portions thereof with the bearing means, being sealed off against the clean chamber when the drive motor is mounted for operation, a disk-shaped ring member being located with precision at the open end of the rotor between the inner circumference of the rotor and the outer race of one of the axially separated bearing means, and means stationary containing leads establishing electrical connection between the internal space and the outside of the motor.