Fluid bearing with non-uniform grooves

1. An apparatus, comprising:

a fluid dynamic bearing,

wherein the fluid dynamic bearing comprises a set of pressure-generating grooves, and

wherein the set of pressure-generating grooves comprises a plurality of chevron-shaped grooves, each chevron-shaped groove comprising at least two characteristics selected from a non-uniform depth, a non-uniform angle, a non-uniform width, or a non-uniform length, selected to provide a predetermined spindle-motor stiffness to the fluid dynamic bearing during steady-state operation and during a shock event.

2. The apparatus of claim 1 , wherein the fluid dynamic bearing comprises

a journal bearing comprising a sleeve and a shaft configured for a fluid therebetween,

wherein the set of pressure-generating grooves comprises a set of upper journal bearing grooves and a set of lower journal bearing grooves.

3. The apparatus of claim 2 , wherein each chevron-shaped groove comprises an outside wall, the vertex of which points to an adjacent chevron-shaped groove, and an inside wall, the vertex of which points to the outside wall of the same chevron-shaped groove.

4. The apparatus of claim 3 , wherein the non-uniform depth comprises the outside wall of each chevron-shaped groove being deeper than the inside wall.

5. The apparatus of claim 3 , wherein the non-uniform depth comprises the inside wall of each chevron-shaped groove being deeper than the outside wall.

6. The apparatus of claim 3 , wherein the non-uniform depth comprises a center groove of each chevron-shaped groove being deeper than both the outside wall and the inside wall.

7. The apparatus of claim 3 , wherein the non-uniform angle comprises the vertex of the outside wall of each chevron-shaped groove being a narrower angle than the vertex of the inside wall.

8. The apparatus of claim 2 , wherein the set of upper journal bearing grooves and the set of lower journal bearing grooves are the same.

9. The apparatus of claim 2 , wherein the sleeve comprises both sets of journal bearing grooves.

10. The apparatus of claim 2 , wherein the shaft comprises both sets of journal bearing grooves.

11. The apparatus of claim 1 , wherein the fluid dynamic bearing comprises

a thrust bearing comprising a thrust surface and an opposing surface configured for a fluid therebetween,

wherein the set of pressure-generating grooves comprises a set of thrust bearing grooves.

12. The apparatus of claim 11 , wherein each chevron-shaped groove comprises an outside wall, the vertex of which points to an adjacent chevron-shaped groove, and an inside wall, the vertex of which points to the outside wall of the same chevron-shaped groove.

13. The apparatus of claim 12 , wherein each chevron-shaped groove comprises a symmetric depth profile selected to provide a predetermined spindle-motor stiffness during steady-state operation and during operation at a temperature higher than an optimum temperature range, wherein the symmetric depth profile comprises a center groove of each chevron-shaped groove of the set of thrust bearing grooves being deeper than both the inside wall and outside wall of the groove.

14. The apparatus of claim 13 , wherein the optimum temperature range is between about 35° C. and 45° C.

15. The apparatus of claim 13 , wherein the center comprises an angled bottom or a flat bottom.

16. The apparatus of claim 11 , wherein the thrust surface comprises the set of thrust bearing grooves.

17. The apparatus of claim 11 , wherein the opposing surface comprises the set of thrust bearing grooves.

18. The apparatus of claim 1 , wherein each chevron-shaped groove comprises a non-uniform depth and at least one characteristic selected from a non-uniform angle, a non-uniform width, or a non-uniform length.

19. The apparatus of claim 18 , wherein each chevron-shaped groove comprises a first segment, from the vertex of the chevron-shaped groove to a first terminus, oriented toward an end of the fluid dynamic bearing, and a second segment, from the vertex of the chevron-shaped groove to a second terminus, oriented toward the center of the fluid dynamic bearing, and wherein the non-uniform width comprises the first terminus of each chevron-shaped groove being narrower than the second terminus.

20. The apparatus of claim 18 , wherein each chevron-shaped groove comprises a first segment, from the vertex of the chevron-shaped groove to a first terminus, oriented toward an end of the fluid dynamic bearing, and a second segment, from the vertex of the chevron-shaped groove to a second terminus, oriented toward the center of the fluid dynamic bearing, and wherein the non-uniform length comprises the first segment of each chevron-shaped groove being longer than the second segment.

21. An apparatus, comprising:

a fluid dynamic bearing,

wherein the fluid dynamic bearing comprises a set of pressure-generating grooves, and

wherein the set of pressure-generating grooves comprises a plurality of chevron-shaped grooves, each chevron-shaped groove comprising at least two characteristics selected from the group consisting of a non-uniform depth, a non-uniform angle, a non-uniform width, and a non-uniform length, selected to provide a predetermined spindle-motor stiffness to the fluid dynamic bearing during steady-state operation and during a shock event.

22. The apparatus of claim 21 , wherein each chevron-shaped groove comprises a non-uniform depth and at least one characteristic selected from the group consisting of a non-uniform angle, a non-uniform width, and a non-uniform length, wherein each chevron-shaped groove comprises a first segment, from the vertex of the chevron-shaped groove to a first terminus, oriented toward an end of the fluid dynamic bearing, and a second segment, from the vertex of the chevron-shaped groove to a second terminus, oriented toward the center of the fluid dynamic bearing, and wherein the non-uniform width comprises the first terminus of each chevron-shaped groove being narrower than the second terminus.