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Easy-fill, easy-press conical bearing

Imported: 24 Feb '17 | Published: 06 Jan '04

Robert A. Nottingham, Jeffry A. LeBlanc, Troy M. Herndon

USPTO - Utility Patents

Abstract

The cone which is pressed onto or otherwise affixed to the shaft to cooperate with the sleeve to form a conical hydrodynamic bearing is modified to provide a flat surface at the axially outer end of the cone most distant from the conical surface which is used to form the conical bearing in cooperation with the bearing seat of the sleeve and the intervening fluid. The sleeve surface facing the second angled surface of the bearing cone is modified to diverge more sharply away from the second surface of the cone, or to simply be spaced further away. In this way, a larger reservoir is formed, diminishing the possibility of oil evaporation and oil loss. Finally, a relatively flat shield is supported from the sleeve overlying the flat upper surface of the cone. The divergence of the upper bearing cone surface from the surrounding sleeve also allows for filling the bearing before the shield is installed. This solves the problem of trying to fill the bearing through a small hole either directly in the protective shield or between the protective shield and the outer diameter of the shaft. Not having the hole in the shield also lowers the likelihood of evaporation or splash loss of oil from the conical bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top land view of a disc drive data storage device in which the present invention is useful.

FIG. 2 is a vertical sectional view of a typical disc drive spindle motor in which the present invention is useful.

FIG. 3A is a vertical sectional view of a known conical bearing; FIGS. 3B and 3C are vertical sectional views of embodiments of the present invention.

Claims

1. A conical hydrodynamic bearing comprising a shaft and a sleeve mounted for rotation around said shaft, the sleeve being supported for rotation relative to the shaft at least in part by the conical bearing comprising a cone fixed to the shaft and having a first angular surface co-operating with a bearing seat surface of the sleeve across a gap filled with a fluid, at least one of the angular bearing surfaces having a plurality of grooves thereon, the bearing cone comprising a secondary angled surface extending from an end of the conical bearing surface toward an axial end of the cone, and ending in surface substantially normal to the axis of the shaft, whereby the cone may be easily pressed in place and located on the shaft.

2. A hydrodynamic bearing as claimed in claim 1 wherein the cone includes a fluid circulation return path extending through the cone and terminating at the secondary angled surface of the cone, the fluid being maintained in the reservoir to cover the exit opening of the return path so that the fluid is maintained between the first surface of the cone and the facing bearing seat surface of the sleeve.

3. A hydrodynamic bearing as claimed in claim 2 wherein the reservoir defined by the surface of the sleeve facing the secondary angled surface of the cone, the surface of the sleeve extending substantially perpendicular to the normal surface by which the cone terminates, the reservoir extending to an end of the conical bearing.

4. The hydrodynamic bearing of claim 1 wherein the second angular surface of the cone is spaced from an inner surface wall of the sleeve to define a reservoir adjacent to an end of the fluid filled conical bearing.

5. A hydrodynamic bearing as claimed in claim 4 further comprising a substantially flat shield extending from an upper surface of the sleeve across the normal surface of the cone.

6. A hydrodynamic bearing as claimed in claim 5 wherein the shield includes a slightly offset portion extending partially across the normal surface of the cone to provide a spacing between the normal surface of the cone and the interior surface of the shield to diminish the possibility of fluid escaping from the hydrodynamic bearing between the shield and the cone normal surface.

7. A hydrodynamic bearing as claimed in claim 4 wherein an interior surface of the sleeve faces the secondary angled surface of the cone and is spaced therefrom to form a fluid reservoir extending axially to an upper axial end of the fluid bearing.

8. A hydrodynamic bearing as claimed in claim 7 wherein the interior surface of the sleeve is spaced from the second angular surface of the cone by a surface extending axially from the bearing seat so that a larger reservoir capable of collecting particles in the fluid is defined.

9. A hydrodynamic bearing as claimed in claim 8 further comprising a substantially flat shield extending from an upper surface of the sleeve across the normal surface of the cone.

10. A spindle motor for use in a disc drive comprising a shaft and a sleeve supported for relative rotation, the sleeve supporting a hub and one or more discs thereon, the sleeve being supported by a conical bearing comprising a cone fixed to the shaft and having a first angular surface co-operating with a bearing seat surface of the sleeve across a gap filled with a fluid, at least one of the angular bearing surfaces having a plurality of grooves thereon, the bearing cone comprising a secondary angled surface extending from an end of the conical bearing surface toward an axial end of the cone, and ending in surface substantially normal to the axis of the shaft, whereby the cone may be easily pressed in place and located on the shaft.

11. The spindle motor of claim 10 wherein the second angular surface of the cone is spaced from an inner surface wall of the sleeve to define a reservoir adjacent to an end of the fluid filled conical bearing.

12. The spindle motor as claimed in claim 11 wherein the cone includes a fluid circulation return path extending through the cone and terminating at the secondary angled surface of the cone, the fluid being maintained in the reservoir to cover the exit opening of the return path so that the fluid is maintained between the first surface of the cone and the facing bearing seat surface of the sleeve.

13. The spindle motor as claimed in claim 12 wherein the reservoir defined by the surface of the sleeve facing the secondary angled surface of the cone, the surface of the sleeve extending substantially perpendicular to the normal surface by which the cone terminates, the reservoir extending to an end of the conical bearing.

14. The spindle motor as claimed in claim 13 further comprising a substantially flat shield extending from an upper surface of the sleeve across the normal surface of the cone.

15. The spindle motor as claimed in claim 4 wherein an interior surface of the sleeve faces the secondary angled surface of the cone and is spaced therefrom to form a fluid reservoir extending axially to an upper axial end of the fluid bearing.

16. The spindle motor as claimed in claim 15 wherein the cone includes a fluid circulation return path extending through the cone and terminating at the secondary angled surface of the cone, the fluid being maintained in the reservoir to cover the exit opening of the return path so that the fluid is maintained between the first surface of the cone and the facing bearing seat surface of the sleeve.

17. The spindle motor as claimed in claim 14 wherein the shield includes a slightly offset portion extending partially across the normal surface of the cone to provide a spacing between the normal surface of the cone and the interior surface of the shield to diminish the possibility of fluid escaping from the hydrodynamic bearing between the shield and the cone normal surface.

18. The spindle motor as claimed in claim 10 wherein the interior surface of the sleeve is spaced from the second angular surface of the cone by a surface extending axially from the bearing seat so that a larger reservoir capable of collecting particles in the fluid is defined.

19. A spindle motor for use in a disc drive comprising a shaft and a sleeve supported for relative rotation, the sleeve supporting a hub and one or more discs thereon, the sleeve being supported by the conical bearing comprising a cone fixed to the shaft and having a first angular surface co-operating with a bearing seat surface of the sleeve across a gap filled with a fluid, at least one of the angular bearing surfaces having a plurality of grooves thereon, the bearing cone comprising a secondary angled surface extending from an end of the conical bearing surface toward an axial end of the cone, and means included in said cone adjacent said secondary angled surface whereby the cone may be readily located on the shaft.

20. A spindle motor as claimed in claim 19 wherein the sleeve comprises means for defining an easily filled axially oriented reservoir.