Low power spindle motor with a fluid dynamic thrust bearing having a reduced outer diameter
View Patent ↗A spindle motor for use in a disk drive having a rotor assembly and a stator assembly. The rotor assembly has a hub and a rotating shaft with an outer diameter, the hub being mounted for rotation on the rotating shaft. The stator assembly has a bearing sleeve with a bottom opening, the rotating shaft being inserted into the bearing sleeve for rotation. A counter-plate is inserted into the bottom opening of the bearing sleeve thereby closing the bottom opening. A thrust plate is mounted on the rotating shaft in opposing relationship with the counter-plate, the thrust plate having an outer diameter. A fluid dynamic thrust bearing is formed between the counter-plate and the thrust plate. A ratio between the outer diameter of the shaft to the outer diameter of the thrust plate is reduced to reduce spindle motor's power consumption.
1. A spindle motor for use in a disk drive comprising:
a rotor assembly, said rotor assembly further comprising a hub and a rotating shaft having an outer diameter, said hub being mounted for rotation on said rotating shaft;
a stator assembly, said stator assembly further comprising a bearing sleeve having a bottom opening, said rotating shaft being inserted into said bearing sleeve for rotation;
a counter-plate inserted into said bottom opening of said bearing sleeve thereby closing said bottom opening; and
a thrust plate mounted on said rotating shaft in opposing relationship with said counter-plate, said thrust plate having an outer diameter;
wherein a fluid dynamic thrust bearing is formed between said counter-plate and said thrust plate, and wherein a ratio between said outer diameter of said shaft to said outer diameter of said thrust washer is less than 1.86.
2. The spindle motor according to claim 1 , wherein said spindle motor is used in a disk drive having a size factor of 3.5″.
3. The spindle motor according to claim 2 , wherein said outer diameter of said thrust plate is approximately 7 mm.
4. The spindle motor according to claim 2 , wherein said ratio is approximately 1.755.
5. The spindle motor according to claim 2 , wherein said ratio is approximately 1.780.
6. The spindle motor according to claim 1 , wherein said spindle motor is used in a disk drive having a size factor of 2.5″ or less.
7. The spindle motor according to claim 6 , wherein said outer diameter of said thrust plate is approximately 5 mm.
8. The spindle motor according to claim 6 , wherein said ratio is approximately 1.666.
9. The spindle motor according to claim 6 , wherein said ratio is approximately 1.656.
10. The spindle motor in accordance with claim 1 further comprising a fluid dynamic radial bearing formed between said rotating shaft and said bearing sleeve.
11. A hard disk drive having a spindle motor, said spindle motor comprising:
a rotor assembly, said rotor assembly further comprising a hub and a rotating shaft having an outer diameter, said hub being mounted for rotation on said rotating shaft;
a stator assembly, said stator assembly further comprising a bearing sleeve having a bottom opening, said rotating shaft being inserted into said bearing sleeve for rotation;
a counter-plate inserted into said bottom opening of said bearing sleeve thereby closing said bottom opening; and
a thrust plate mounted on said rotating shaft in opposing relationship with said counter-plate, said thrust plate having an outer diameter;
wherein a fluid dynamic thrust bearing is formed between said counter-plate and said thrust plate, and wherein a ratio between said outer diameter of said shaft to said outer diameter of said thrust plate is less than 1.86.
12. The disk drive according to claim 11 , wherein said disk drive has a size factor of 3.5″.
13. The disk drive according to claim 12 , wherein said outer diameter of said thrust plate is approximately 7 mm.
14. The disk drive according to claim 12 , wherein said ratio is approximately 1.755.
15. The disk drive according to claim 12 , wherein said ratio is approximately 1.780.
16. The disk drive according to claim 11 , wherein said disk drive has a size factor of 2.5″ or less.
17. The disk drive according to claim 16 , wherein said outer diameter of said thrust plate is approximately 5 mm.
18. The disk drive according to claim 16 , wherein said ratio is approximately 1.666.
19. The disk drive according to claim 16 , wherein said ratio is approximately 1.656.
20. The disk drive in accordance with claim 11 further comprising a fluid dynamic radial bearing formed between said rotating shaft and said bearing sleeve.