Hard disc drive with base incorporating a spindle motor stator

• US 6,501,616 B1
• Filed: 12/22/1999
• Issued: 12/31/2002
• Est. Priority Date: 07/29/1999
• Status: Expired due to Fees

• Current Assignee: Nytell Software LLC (Intellectual Ventures LLC)
• Original Assignee: Encap Motor Corporation
• Inventors: Neal, Griffith D.
• Primary Examiner(s): Nguyen, Hoa T.
• Assistant Examiner(s): Watko, Julie Anne
• Application Number:
  US09/470,424
• Time in Patent Office: 1,105 Days
• Field of Search: 360/99.08, 360/98.07, 360/97.02, 369/258, 369/263, 369/266, 369/269, 369/264
• US Class Current: 360/99.08
• CPC Class Codes: G11B 19/2009 Turntables, hubs and motors for disk drives; Mounting of motors in the drive means for clamping of disk to turntable G11B17/022 and subgroups
• CPC Class Codes: H02K 1/146 consisting of a generally annular yoke with salient poles
• CPC Class Codes: H02K 1/185 to outer stators
• CPC Class Codes: H02K 1/187 to inner stators
• CPC Class Codes: H02K 11/00 Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection casings, enclosures or supports H02K5/00
• CPC Class Codes: H02K 15/12 Impregnating, heating or drying of windings, stators, rotors or machines
• CPC Class Codes: H02K 15/16 Centering rotors within the stator; Balancing rotors
• CPC Class Codes: H02K 21/16 having annular armature cores with salient poles with homopolar co-operation H02K21/20
• CPC Class Codes: H02K 21/22 with magnets rotating around the armatures, e.g. flywheel magnetos
• CPC Class Codes: H02K 21/24 with magnets axially facing the armatures, e.g. hub-type cycle dynamos
• CPC Class Codes: H02K 2211/03 Machines characterised by circuit boards, e.g. pcb
• CPC Class Codes: H02K 3/46 Fastening of windings on the stator or rotor structure
• CPC Class Codes: H02K 5/02 Casings or enclosures characterised by the material thereof
• CPC Class Codes: H02K 5/08 Insulating casings
• CPC Class Codes: H02K 5/1675 radially supporting the rotary shaft at only one end of the rotor H02K5/1677 takes precedence
• CPC Class Codes: H02K 5/1677 radially supporting the rotor around a fixed spindle; radially supporting the rotor directly
• CPC Class Codes: H02K 5/1735 radially supporting the rotary shaft at only one end of the rotor H02K5/1737 takes precedence
• CPC Class Codes: H02K 5/1737 radially supporting the rotor around a fixed spindle; radially supporting the rotor directly
• CPC Class Codes: H02K 5/225 Terminal boxes or connection arrangements specially adapted for submersible motors H02K5/132
• CPC Class Codes: H02K 7/085 radially supporting the rotary shaft at only one end of the rotor H02K7/086, H02K7/09 take precedence
• CPC Class Codes: H02K 7/14 : Structural association with mechanical loads, e.g. with hand-held machine tools or fans with fan or impeller for cooling the machine H02K9/06

Abstract

The present invention is directed to a high speed spindle motor comprising a stator assembly including a stator having multiple conductors that create a plurality of magnetic fields when electrical current is conducted by the conductors and a body of a phase change material such as a thermoplastic substantially encapsulating the stator. A rotatable hub having a magnet connected thereto is in operable proximity to the stator. The high speed motor also includes a shaft, a bearing surrounding the shaft and one of the bearing or shaft being fixed to the stator assembly and the other of the bearing or shaft being fixed to the rotatable hub. Hard disc drives using the motor, and methods of developing and constructing the motor and hard disc drives are also disclosed.

Claims

1. A hard disc drive comprising:

a) a base assembly comprising a body of phase change material the body of phase change material both substantially encapsulating a stator and supporting a shaft;

b) a hub having a magnet connected thereto in operable proximity to the stator, the hub being rotatably supported by a bearing on said shaft;

c) one or more discs supported on said hub; and

d) a read/write head pivotally mounted to the base assembly for accessing data and recording or reading data on the one or more discs.

2. The hard disc drive of claim 1 wherein the base assembly further comprises a second shaft supported by the body of phase change material, the second shaft supporting the read/write head in operable proximity to the one or more discs.

3. The hard disc drive of claim 2 wherein the second shaft is supported by the body of phase change material by being injection molded therewith.

4. The hard disc drive of claim 1 wherein the body of phase change material is a monolithic body of thermoplastic material.

5. The hard disc drive of claim 1 further including a cover, the cover being attached and cooperating with the body of phase change material to provide a housing for the hard disc drive.

6. The hard disc drive of claim 1 wherein the stator comprises a core having a plurality of poles and windings around said poles.

7. The hard disc drive of claim 1 wherein the shaft is supported by the body of phase change material by being injected molded therewith.

8. The hard disc drive of claim 1 wherein the shaft is supported by the body of phase change material by being added to the base assembly after the base assembly is formed.

9. A hard disc drive comprising:

a) a high speed motor having;

i) a stator assembly comprising a stator having multiple conductors that create a plurality of magnetic fields when electrical current is conducted by the conductors and a body of a phase change material substantially encapsulating the stator, the phase change material also forming at least a part of a base assembly for the hard disc drive;

ii) a hub having a magnet connected thereto in operable proximity to the stator;

iii) a shaft having an axis;

iv) a bearing allowing rotation of the hub about the axis of the shaft; and

v) one of the shaft or bearing being fixed to the stator assembly by the body of phase change material and the other of the shaft or bearing being fixed relative to the rotatable hub;

b) one or more discs supported on said hub; and

c) a read/write head pivotally mounted to the base assembly for accessing data and recording or reading data on the one or more discs.

10. The hard disc drive of claim 9 wherein the shaft is fixed to the stator assembly.

11. The hard disc drive of claim 9 wherein the shaft is fixed relative to the body.

12. The hard disc drive of claim 9 wherein the shaft is freely rotatable relative to the body.

13. The hard disc drive of claim 9 wherein the bearing is fixed to the stator assembly.

14. The hard disc drive of claim 13 wherein bearing is fixed to the body.

15. The hard disc drive of claim 14 wherein the magnet is fixed to the hub.

16. The hard disc drive of claim 9 wherein the shaft is fixed to the hub.

17. The hard disc drive of claim 9 wherein the conductors comprise a plurality of windings.

18. The hard disc drive of claim 9 wherein the stator assembly and magnet are generally coplanar.

19. The hard disc drive of claim 9 wherein the bearing comprises a hydrodynamic bearing.

20. The hard disc drive of claim 9 wherein a solid insert is also substantially encapsulated within the body when the stator is encapsulated.

21. The hard disc drive of claim 9 wherein the phase change material includes ceramic particles.

22. The hard disc drive of claim 9 wherein the phase change material has a coefficient of linear thermal expansion of less than 2×

10<sup>−

5</sup> in/in/°

F. throughout the range of 0-250°

F.

23. The hard disc drive of claim 9 wherein the bearing comprises steel, the hub comprises aluminum and the phase change material haves a coefficient of linear thermal expansion that is between the coefficient of linear thermal expansion of the steel and the coefficient of linear thermal expansion of the aluminum.

24. The hard disc drive of claim 9 wherein the phase change material comprises polyphenyl sulfide.

25. The hard disc drive of claim 9 wherein the phase change material comprises liquid crystal polymer.

26. The hard disc drive of claim 9 wherein the phase change material comprises either PET, PBT, or PCT polyester.

27. The hard disc drive of claim 9 wherein the phase change material has a dielectric strength of at least 250 volts/mil.

28. The hard disc drive of claim 9 wherein the phase change material has a thermal conductivity of at least 0.7 watts/meter°

K. at 23°

C.

29. The hard disc drive of claim 9 wherein the phase change material is a thermoplastic material and is injection molded to form the body.

30. The hard disc drive of claim 9 wherein the phase change material has a coefficient of linear thermal expansion of less than 1.5×

10<sup>−

5</sup> in/in/°

F. throughout the range of 0-250°

F.

31. The hard disc drive of claim 9 wherein the phase change material has a coefficient of linear thermal expansion of between about 0.8×

10<sup>−

5</sup> in/in/°

F. and about 1.2×

10<sup>−

5</sup> in/in/°

F. throughout the range of 0-250°

F.