Spindle motor having a fluid dynamic bearing system

Abstract

The invention relates to a spindle motor having a fluid dynamic bearing system, used particularly for driving the storage disks of hard disk drives, having a baseplate, a stationary bearing bush disposed in an opening in the baseplate, a shaft rotatably supported in an axial bore in the bearing bush by means of the fluid dynamic bearing system, a hub connected to the shaft, and an electromagnetic drive system. The invention is characterized in that the shaft has a flange that is fixed in an opening in the hub and whose outside diameter is significantly larger than the smallest outside diameter of the shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

On the left and right hand sides of the drawings, half sections of different embodiments of the spindle motors according to the invention (or parts thereof) are shown.

FIG. 1A shows an embodiment of parts of a spindle motor according to the invention having a stepped shaft flange.

FIG. 1B shows an embodiment of a part of a spindle motor according to the invention having a straight shaft flange and a hub pressed on from “below”.

FIG. 2A shows an embodiment of a part of a spindle motor according to the invention having an integrated stopper element.

FIG. 2B shows an embodiment of a part of a spindle motor according to the invention having a hub resting on the upper surface of the shaft flange.

FIG. 3A shows an embodiment of a part of a spindle motor according to the invention having a stepped shaft flange.

FIG. 3B shows an embodiment of a part of a spindle motor according to the invention having a straight shaft flange and an integrated stopper element.

FIG. 4 shows an embodiment of a spindle motor according to the invention having a connecting sleeve between the shaft flange and the hub.

FIG. 5A shows an embodiment of a spindle motor according to the invention that substantially corresponds to FIG. 1A.

FIG. 5B shows an embodiment of a spindle motor according to the invention that substantially corresponds to FIG. 1B.

FIG. 6A shows an embodiment of a spindle motor according to the invention having a straight shaft flange and an integrated stopper ring.

FIG. 6B shows an embodiment of a spindle motor according to the invention having a straight shaft flange and an integrated stopper ring.

Claims

1. A spindle motor having a fluid dynamic bearing system, used particularly for driving the storage disks of hard disk drives, having a baseplate (6; 306; 406), a stationary bearing bush (3; 103; 203; 303; 403) disposed in an opening in the baseplate, a shaft (1; 103; 203; 303; 403) rotatably supported in an axial bore in the bearing bush by means of the fluid dynamic bearing system, a hub (4; 104; 204; 304; 404) connected to the shaft, and an electromagnetic drive system (7, 8; 307, 308; 407, 408), characterized in that the shaft has a flange (2; 102; 202; 302; 402) that is fixed in an opening in the hub and whose outside diameter is significantly larger than the outside diameter of the shaft.

2. A spindle motor according to claim 1, characterized in that the outside diameter of the flange (2; 102; 202; 302; 402) is at least 1.5 times the smallest diameter of the shaft.

3. A spindle motor according to claim 1, characterized in that the outside diameter of the flange (2; 102; 202; 302; 402) corresponds substantially to the outside diameter of the bearing bush.

4. A spindle motor according to claim 1, characterized in that the flange (2; 102; 202; 302; 402) is integrally formed as a single piece with the shaft.

5. A spindle motor according to claim 1, characterized in that a space (11; 111; 211; 311; 411) formed by the interfaces between the hub (4; 104; 204; 304; 404) and the bearing bush (3; 103; 203; 303; 403) is conical in cross-section.

6. A spindle motor according to claim 1, characterized in that the outside diameter of the flange (2; 102; 202; 302; 402) is designed with a step.

7. A spindle motor according to claim 1, characterized in that the flange (2;. 102; 202; 302; 402) is connected to the hub (4; 104; 204; 304; 404) by means of a press fit.

8. A spindle motor according to claim 1, characterized in that an axial bearing (13; 113; 213; 313; 413) is formed between the flange and the bearing bush (3; 103; 203; 303; 403).

9. A spindle motor according to claim 1, characterized in that a recirculation channel (15; 315; 415) connects one end face of the bearing bush (3; 303; 403) to its other end face by means of which pressure is equalized in the adjoining regions of a bearing gap (5; 305; 405).

10. A spindle motor according to claim 1, characterized in that the flange (2; 102; 202; 302; 402) is connected to the hub (4; 104; 204; 304; 404) by means of a welded joint.

11. A spindle motor according to claim 1, characterized in that the hub (4; 104; 204; 304; 404) is pressed onto the shaft or the flange respectively (2; 102; 202; 302; 402) from below.

12. A spindle motor according to claim 1, characterized in that the axial play of the shaft (1; 101; 201; 301; 401) is restricted by a stopper element that is formed by parts of the hub (4; 104; 204; 304; 404) and of the bearing bush (3; 103; 203; 303; 403).

13. A spindle motor according to claim 12, characterized in that the axial play of the shaft (1; 101; 201; 301; 401) is restricted by an end plate (9; 109; 209; 309; 409) that is disposed at one end of the shaft.

14. A spindle motor according to claim 13, characterized in that the end plate is connected to the shaft (1; 101; 201; 301; 401) by a screwed, pressed, bonded or welded joint.

15. A spindle motor according to claim 1, characterized in that the finishing work to the surfaces of the shaft and/or the hub is carried out after the two components have been joined.

16. A hard disk drive having a spindle motor according to claim 1.