Stator assembly

• US 6,362,554 B1
• Filed: 12/22/1999
• Issued: 03/26/2002
• Est. Priority Date: 07/29/1999
• Status: Expired due to Term

• Current Assignee: Intellectual Ventures II LLC (Intellectual Ventures LLC)
• Original Assignee: Encap Motor Corporation
• Inventors: Neal, Griffith D.
• Primary Examiner(s): Waks, Joseph
• Application Number:
  US09/470,429
• Time in Patent Office: 825 Days
• Field of Search: 310/43, 310/51, 310/89, 310/254, 295/96, 296/06, 264/272.13, 264/272.2
• US Class Current: 310/216.003
• 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 1/2788 the rotor consisting of a single magnet or two or more axially juxtaposed single magnets
• CPC Class Codes: H02K 1/34 Reciprocating, oscillating or vibrating parts of the magnetic circuit
• 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 15/10 Applying solid insulation to windings, stators or rotors
• 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 3/38 around winding heads, equalising connectors, or connections thereto
• 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
• CPC Class Codes: Y10T 29/49009 : Dynamoelectric machine

Abstract

A high speed spindle motor is constructed from a stator assembly that includes 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 stator assembly comprising

a) a magnetically inducible core having a plurality of salient poles;

b) a plurality of conductors comprising wire windings around said poles such that magnetic fields are induced in the core when electrical current is conducted through the conductors; and

c) a body of a phase change material substantially encapsulating the core and the conductors, the phase change material having a coefficient of linear thermal expansion of between about 0.8×

10<sup>−

5</sup> in/in °

F. and about 1.5×

10<sup>−

5</sup> in/in °

F. throughout the range of 0-250°

F.

2. The stator assembly of claim 1 wherein the phase change material has a coefficient of thermal conductivity of at least 0.7 watts/meter°

K. at 23°

C.

3. The stator assembly of claim 1 further comprising terminals for connecting the conductors to a power source, the terminals being partially encapsulated in the body.

4. The stator assembly of claim 1 further comprising one or more metal inserts molded into the body, the inserts providing one or more properties selected from the group consisting of increased rigidity, increased thermal conductivity, vibration dampening and enhanced magnetic effect.

5. The stator assembly of claim 1 wherein the core is made from steel laminations.

6. The stator assembly of claim 1 wherein the salient poles are directed outwardly.

7. The stator assembly of claim 1 wherein the salient poles are directed inwardly.

8. The stator of claim 1 wherein the phase change material includes ceramic particles.

9. The stator of claim 1 wherein the phase change material comprises polyphenyl sulfide.

10. A motor comprising the stator assembly of claim 1.

11. A stator assembly comprising:

a) a stator having a magnetically inducible core with salient poles and multiple conductors that create a plurality of magnetic fields when electrical current is conducted through the conductors; and

b) a body of phase change material substantially encapsulating the core and the conductors, the phase change material having a coefficient of linear thermal expansion of between about 0.8×

10<sup>−

5</sup> in/in °

F. and about 1.5×

10<sup>−

5</sup> in/in °

F. throughout the range of 0-250°

F., a thermal conductivity of at least 0.7 watts/meter °

K. and a dielectric strength of at least 250 volts/mil.

12. A stator assembly comprising:

a) a stator having a core with salient poles and multiple conductors that create a plurality of magnetic fields when electrical current is conducted through the conductors; and

b) a body of phase change material substantially encapsulating the conductors, the phase change material being an injection molded thermoplastic having a coefficient of linear thermal expansion of between about 0.8×

10<sup>−

5</sup> in/in °

F. and about 1.5×

10<sup>−

5</sup> in/in °

F. throughout the range of 0-250°

F., a thermal conductivity of at least 0.7 watts/meter°

K. and a dielectric strength of at least 250 volts/mil.