Disk storage drive

Abstract

A disk memory drive includes a brushless drive outer rotor motor having an internal space and a stator with windings. The outer rotor coolly encircles the stator and a substantially cylindrical air gap is defined between the stator and the rotor. The rotor includes permanent magnets and a hub fixedly connected with the magnet. A disk mounting section is provided on the hub for accommodating at least one storage disk positioned in a clear space, the mounting section being adapted to extend through a central aperture of the storage disk. The windings and the magnets interacting with the windings are disposed for at least half of the axial longitudinal dimension thereof within a space surrounded by the disk mounting section of the hub. Bearings rotatably mount the rotor and the hub.

What is claimed is: . .1. 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 open end coaxially encircling the stator and a substantially cylindrical air gap defined between the stator and the rotor, the rotor including a hub and including permanent magnet means having a predetermined axial extension fixedly connected therewith for magnetic interaction with said winding means; a disk mounting section provided on the hub for accommodating at least one storage disk located in a clean chamber surrounding said rotor, the mounting section 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 upper and lower bearing means having inner and outer races on a stationary shaft rotatably mounting the rotor and the hub on the shaft, the rotor also including rotational position indicator means interacting with stationary rotational position sensor 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 containing the disk, and 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 the lower bearing means..!.. .2. A disk memory drive according to claim 1, wherein the rotational position indicator means includes permanent magnet poles disposed on the disk-shaped ring member for rotation therewith and wherein the rotational position sensor means is sensitive to magnetic fields and interacts with the permanent magnet poles..!.. .3. A disk memory drive according to claim 1 wherein the rotational position sensor means is mounted on a printed circuit board opposite the disk-shaped member ring..!.. .4. A disk memory drive according to claim 3, further including electronic commutation devices for the electromagnetization of the stator also being mounted on the printed circuit board..!.. .5. A disk memory drive according to claim 3, wherein the printed circuit board is supported on a flange fixed on the stationary shaft..!.. .6. A disk memory drive according to claim 1, further including a magnetic shield means at least circumferentially surrounding the stator for shielding a clean chamber containing the disk from the magnetic flux of the stator and wherein the stationary shaft is of constant diameter and the outer rotor includes a bell-shaped housing with a substantially closed end and a substantially open end, the stator together with the magnetic shield being firmly mounted to the stationary shaft, the inner race of each bearing being firmly mounted on the stationary shaft on either axial side of the stator, the upper bearing being positioned inwardly adjacent of the closed end of the bell-shaped outer rotor, and the lower bearing being positioned adjacent the open end 
     
        of the bell-shaped outer rotor..!.. .7.  A disk memory drive according to claim 1, wherein the internal space of the motor is sealed by means of a cover located at the open end of the outer rotor, the cover also serving as a bearing mounting flange, and the rotational position indicator means being mounted on the outside of the motor cover with respect to the sealed inner space of the motor..!.. .8. A disk memory drive according to claim 1, wherein the outer rotor includes an outer rotor casing of ferromagnetic material, the outer rotor serving also as the hub, the rotational position indicator being mounted on a lower part of the hub outside the sealed inner space of the motor..!.. .9. A disk memory drive according to claim 1, wherein further comprising a bearing mounting flange having projections in the actual axial direction that project into the disk-shaped ring member, and a labyrinth seal located between the projections and the ring member formed by a combination of cylindrical and radially flat gaps having only dimensions of normal clearances between moving parts..!.. .10. A disk memory drive according to claim 9, wherein the projections on the bearing mounting flange are rectangular in section and extend axially..!.. .11. A disk memory drive according to claim 9, wherein the ring member on which part of the bearing race is mounted is substantially flush in the axial direction with the mounting flange, the ring member 
     
     
        being inserted in the outer rotor casing that forms the hub..!.12. A disk memory drive having a brushless drive motor, comprising a stator having a predetermined axial extension, a coaxially positioned outer rotor and circling the stator and defining therebetween a substantially cylindrical air gap, the rotor having a predetermined axial extension, a cylindrically shaped permanent motor magnet disposed adjacent the air gap on the inner circumference of the rotor to rotate therewith and magnetically interact with the stator, a hub on the outer circumference of the rotor firmly fixed to the motor magnet, the hub being provided on its outer circumference with a disk mounting section which extends through the central opening in a storage disk to mount the disk and allowing at least one storage disk to be accommodated thereon, a clean chamber surrounding the disk mounting section to contain the mounted disk therein, at least half of the axial extension of both the stator winding and of the motor magnet interacting therewith being positioned within the space encompassed by the disk mounting section of the hub, a stationary shaft having upper and lower bearing means mounted thereon for rotatably mounting the rotor with hub on the shaft, and seals located axially above the upper and below the lower bearings for sealing the space therebetween from the outer clean 
     
     
        chamber. 13. A disk memory drive according to claim 12, wherein the seals 
     
     
        are magnetic liquid seals. 14. A disk memory drive according to claim 12, wherein the stationary shaft projects axially externally of the upper and 
     
     
        lower seals. 15. A disk memory drive according to claim 12, wherein the 
     
     
        seals are labyrinth seals. 16. A disk memory drive according to claim 15, wherein the labyrinth seal is formed of a member having a substantially L-shaped cross section being mounted on and extending radially from the stationary shaft, the short leg of the L-shaped member extending axially 
     
     
        outwardly. 17. A disk memory drive according to claim . .15,.!. .Iadd.16 .Iaddend.further including a ring member of L-shaped cross section being provided on the rotor and being opposite and complementary to the stationary mounted L-shaped member, the longer leg of the L-shaped member on the rotor extending inwardly toward the stationary shaft with only a 
     
     
        clearance dimension separating the two parts. 18. A disk memory drive according to claim . .15,.!. .Iadd.17 .Iaddend.wherein the stationary L-shaped member lies inboard axially and is substantially encompassed by the rotating L-shaped ring, a flat radial labyrinth gap being formed radially between the respective short legs of the L-shaped members.