Disk storage device having a hub sealing member feature

Abstract

A disk memory drive includes a brushless drive outer rotor motor having an internal space and a stator with windings. The outer rotor coaxially 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 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. 
     
     
       2. A disk memory drive according to  claim 1 , wherein said rotating means interacting with said stationary means comprises rotational position indicator means which 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 2 , wherein the shaft is a stationary shaft. 
     
     
       4. A disk memory drive according to  claim 3  wherein the rotational position sensor means is mounted on a printed circuit board opposite the disk-shaped member ring. 
     
     
       5. A disk memory drive according to  claim 4 , further including electronic commutation devices for the electromagnetization of the stator also being mounted on the printed circuit board. 
     
     
       6. A disk memory drive according to  claim 4 , wherein the printed circuit board is supported on a flange fixed to the stationary shaft. 
     
     
       7. A disk memory drive according to  claim 3 , 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. 
     
     
       8. A disk memory drive according to  claim 2 , 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. 
     
     
       9. A disk memory drive according to  claim 2 , 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. 
     
     
       10. A disk memory drive according to  claim 2 , 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. 
     
     
       11. A disk memory drive according to  claim 10 , wherein the projections on the bearing mounting flange are rectangular in section and extend axially. 
     
     
       12. A disk memory drive according to  claim 10 , 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. 
     
     
       13. A disk memory drive having a brushless drive motor, comprising a stator having a predetermined axial extension, a coaxially positioned outer rotor encircling the stator and defining therebetween a substantially cylindrical air gap, the rotor having an inner circumference and an outer circumference and a predetermined axial extension, a cylindrically shaped permanent magnet having a predetermined axial extension disposed adjacent the air gap on the inner circumference of the rotor to rotate therewith and magnetically interact with the stator, a ferromagnetic hub on the outer circumference of the rotor firmly fixed to the motor magnet, the hub radially surrounding the predetermined axial extension of said permanent magnet and being provided on its outer circumference with a disk mounting section which can extend through the central opening in a storage disk to mount at least one storage disk thereon, a shaft having first and second axially separated bearing means mounted thereon rotatably mounting the rotor with hub on the shaft, and seals located axially outside of the axial extension of the first and second bearing means for sealing the space therebetween. 
     
     
       14. A disk memory drive according to  claim 13 , wherein the shaft is a stationary shaft. 
     
     
       15. A disk memory drive according to  claim 14 , wherein the seals are magnetic liquid seals. 
     
     
       16. A disk memory drive according to  claim 14 , wherein the seals are labyrinth seals. 
     
     
       17. A disk memory drive according to  claim 14 , wherein the stationary shaft projects axially externally of the upper and lower seals. 
     
     
       18. A disk memory drive according to  claim 14 , 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. 
     
     
       19. A disk memory drive according to  claim 16 , 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. 
     
     
       20. A disk memory drive according to  claim 16 , 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. 
     
     
       21. A disk storage device, comprising in combination: 
       
         a housing that encloses a clean chamber for providing an environment that is maintained substantially contaminant free;  
       
       
         at least one hard magnetic storage disk provided in said clean chamber for rotation about an axis, said at least one disk having a central opening;  
       
       
         at least one data head that is provided in said clean chamber and that allows information to be stored on and read from said at least one hard magnetic storage disk;  
       
       
         a motor support member forming part of said housing;  
       
       
         a hub member that is provided in said clean room, said hub member having a cylindrical portion that extends through the central opening of said at least one disk whereby said at least one disk is mounted on and rotated by said disk support member, said disk support member including an end wall, wherein a generally enclosed space is defined between adjacent surfaces of said disk support member and said motor support member, and wherein a plurality of holes are formed in said end wall that are generally parallel to said axis and extend through said end wall from said generally enclosed space to said clean room;  
       
       
         a brushless direct current motor that is mounted on said motor support member and that is adapted to rotate said disk support member about said axis, said brushless direct current motor including a stator concentric with said axis, a stator winding disposed on said stator, and a rotor mounted for rotation about said axis relative to said stator, said rotor having a permanent magnetic ring mounted on a magnetically conductive member in a manner such that a generally cylindrical air gap is defined between adjacent surfaces of said stator and said permanent magnetic ring, said brushless direct current motor further including a shaft aligned on an axis and at least one bearing affixed to said shaft;  
       
       
         a disk clamp assembly that is operatively engaged with said plurality of holes to secure said at least one disk to said hub member; and  
       
       
         wherein said hub member further includes a sealing member that is disposed on a surface of said hub member that defines a portion of said generally enclosed space, said sealing member generally reducing the transfer of contaminant particles that are created by the engagement of said disk clamp assembly with said hub member into said clean chamber.  
       
     
     
       22. The disk storage device of  claim 21  wherein said magnetically conductive member provides at least a portion of a magnetic return path for said permanent magnetic ring.  
     
     
       23. The disk storage device of  claim 21  wherein said shaft is rotatable about said axis.  
     
     
       24. The disk storage device of  claim 21  wherein said permanent magnetic ring is formed from a generally radially oriented permanent magnetic material.  
     
     
       25. The disk storage device of  claim 24  wherein said permanent magnetic ring is radially magnetized to form a plurality of permanent magnets of alternating polarity, the radial magnetization of said permanent magnets varies in a substantially trapezoidal manner in a circumferential direction, and a pole gap is defined between the magnetic poles in each of said permanent magnets such that the circumferential extent of each pole gap is small compared to the circumferential extent of the magnetic poles in the pair of permanent magnets adjacent thereto.  
     
     
       26. The disk storage device of  claim 25  wherein said permanent magnetic material comprises a mixture of ferrite and an elastic material.  
     
     
       27. The disk storage device of  claim 21  said hub member comprises a generally non- magnetically conductive material.    
     
     
       28. The disk storage device of  claim 27  wherein said generally non- magnetically conductive material comprises aluminum.    
     
     
       29. The disk storage device of  claim 21  wherein said rotor comprises an external rotor.  
     
     
       30. The disk storage device of  claim 21  wherein said permanent magnetic ring coaxially surrounds the portion of said stator that forms said air gap.  
     
     
       31. A disk storage device, comprising in combination: 
       
         a housing that encloses a clean chamber for providing an environment that is maintained substantially contaminant free;  
       
       
         at least one hard magnetic storage disk provided in said clean chamber for rotation about an axis, said at least one disk having a central opening;  
       
       
         at least one data head that is provided in said clean chamber and that allows information to be stored on and read from said at least one hard magnetic storage disk;  
       
       
         a hub member that is provided in said clean room, said hub member having a cylindrical portion that extends through the central opening of said at least one disk whereby said at least one disk is mounted on and rotated by said disk support member, said disk support member further including an end wall, a plurality of holes being formed in said end wall that are generally parallel to said axis and extend through said end wall;  
       
       
         a brushless direct current motor that is adapted to rotate said disk support member about said axis, said brushless direct current motor including a stator concentric with said axis, a stator winding disposed on said stator, and a rotor mounted for rotation about said axis relative to said stator, said rotor having a permanent magnetic ring mounted on a magnetically conductive member in a manner such that a generally cylindrical air gap is defined between adjacent surfaces of said stator and said permanent magnetic ring, said brushless direct current motor further including a shaft aligned on an axis and at least one bearing affixed to said shaft; and  
       
       
         a cover ring that is disposed on a surface of said hub member so that the transfer of contaminant particles from said hub member into said clean chamber is generally reduced, said contaminant particles being created by the engagement of a disk clamp assembly with said plurality of holes in said hub member.  
       
     
     
       32. The disk storage device of  claim 31  wherein said magnetically conductive member provides at least a portion of a magnetic return path for said permanent magnetic ring.  
     
     
       33. The disk storage device of  claim 31  wherein said shaft is rotatable about said axis.  
     
     
       34. The disk storage device of  claim 31  wherein said permanent magnetic ring is formed from a generally radially oriented permanent magnetic material.  
     
     
       35. The disk storage device of  claim 34  wherein said permanent magnetic ring is radially magnetized to form a plurality of permanent magnets of alternating polarity, the radial magnetization of said permanent magnets varies in a substantially trapezoidal manner in a circumferential direction, and a pole gap is defined between the magnetic poles in each of said permanent magnets such that the circumferential extent of each pole gap is small compared to the circumferential extent of the magnetic poles in the pair of permanent magnets adjacent thereto.  
     
     
       36. The disk storage device of  claim 35  wherein said permanent magnetic material comprises a mixture of ferrite and an elastic material.  
     
     
       37. The disk storage device of  claim 31  said hub member comprises a generally non- magnetically conductive material.    
     
     
       38. The disk storage device of  claim 37  wherein said generally non- magnetically conductive material comprises aluminum.    
     
     
       39. The disk storage device of  claim 31  wherein said rotor comprises an external rotor.  
     
     
       40. The disk storage device of  claim 31  wherein said permanent magnetic ring coaxially surrounds the portion of said stator that forms said air gap.