Seagate Technology Incorporated

Mohamed Mizanur Rahman

Hans L Leuthold

Gunter Karl Heine

Raquib Uddin Khan

Alan Lyndon Grantz

Samnathan Murthy

Norbert Steven Parsoneault

Roger Allen Addy

Michael David Kennedy

Matt L Shumway

Wesley R Clark

Anthony Joseph Aiello

Troy Michael Herndon

Robert Alan Nottingham

Jeffry Arnold LeBlanc

Susan Immisch

Etoli Wolff

Peter R Riegler

Steve Parsoneault

Norbert Steve Parsoneault

To reduce the whirling air vortices which are normally formed at the disc tip, the outer edge of the disc surface may be gradually thinned down to a sharp tip. An alternative approach, the disc tip is gradually reduced in width and rounded at its outer edge. A flow obstruction may be incorporated in the shroud adjacent the edge of the disc tip. This obstruction may comprise a small substantially rectangular insert extending from the inner edge of the housing. Or, the inner surface of the portion of the housing adjacent the ends of the disc may incorporate grooves therein. These grooves, which are roughly herringbone in shape, and would have their center near either the edge of disc in a single disc environment or mid-way between the disc in a two disc environment.

Control flow instability to reduce disk flutter and half frequency whirl

A method of designing an improved bearing system is provided. In one embodiment, the method for designing a fluid dynamic bearing system includes determining a first stability ratio for a first journal bearing configuration. The method further includes determining a second stability ratio for a second journal bearing configuration. In one embodiment, the first configuration has two sub-journal bearings and the second configuration has three sub-journal bearings. The two stability ratios may then be compared to determine whether adding a sub-journal increases the stability ratio of the bearing system.

Method for designing a fluid dynamic bearing system

A fluid dynamic bearing is provided having two surfaces rotatable with respect to each other, a lubricating medium located in a gap between the two surfaces during rotation of the bearing, and an interrupted and offset groove pattern formed on one of the two surfaces to distribute the lubricating medium over the surface of the bearing. The groove design is intended to be useable in either a journal, thrust or other fluid bearing design.

Grooving pattern for grooved fluid bearing

In one embodiment, a plurality of axially oriented bearings defined along gaps between rotor and stator are provided to provide radial stiffness to the system; and these bearings are coupled together by radially oriented gaps. Grooves and/or magnets may be defined in order to maintain the stability and relative spacing of the gaps, while allowing free relative rotation of parts of the system with minimum power loss. A central conical bearing may be provided, having a fluid dynamic bearing around its conical surface, and being connected to an axially parallel but radially displaced axially oriented journal style bearing. The combined effects of these bearings is sufficient to maintain or even enhance the overall stability of the system.

Multiple radial/axial surfaces to enhance fluid bearing performance

A bearing system in which an axially stiff narrow gap fluid dynamic gas bearing is preloaded by an axially less stiff larger gap fluid dynamic bearing. As an example two fluid dynamic bearings are provided spaced apart along a shaft, radially aligned with an air/gas filled spherical or conical or similar type bearing. A shaft end thrust bearing is also defined for axial support.

Low power hybrid bearing

A bearing system in which an axially stiff narrow gap fluid dynamic gas bearing. As an example two fluid dynamic bearings are provided spaced apart along a shaft, one of the bearings comprising a fluid dynamic bearing, the other comprising an air bearing. The fluid dynamic bearing has a larger gap, while the air bearing has a relatively small gap. The overall working surface area of the air bearing may be twice as much or more than the working surface area of the fluid bearing.

Hybrid spindle bearing

A bearing system in which an axially stiff narrow gap fluid dynamic gas bearing is preloaded by an axially less stiff larger gap fluid dynamic bearing. As an example two fluid dynamic bearings are provided spaced apart along a shaft, one of the bearings comprising a fluid dynamic bearing, the other comprising an air bearing. The fluid dynamic bearing has a larger gap, while the air bearing has a relatively small gap. The overall working surface area of the air bearing may be twice as much or more than the working surface area of the fluid bearing.

Bearing performance enhancement utilizing sleeve/hub radial surfaces

A hydrodynamic bearing system where the bearing includes a shaft and two independent bearings, including a top cone or bi-sphere and a bottom cone or bi-sphere separated by a segment of the shaft. The bearing includes a hub supported bearing element rotating around the shaft and the shaft supported top cone and bottom cone; complementary surfaces of the bearing element and the cone define a narrow gap between the bearing support element for the bearing fluid. Sealing plates or seal elements define a fluid gap with a radially extending face of the cone; a gap also exists between an interior surface portion of each cone and the shaft. These gaps are connected so that separate flow paths are established, one around the top cone or bi-sphere and one around the bottom cone or bi-sphere. By providing two independent bearings, the stator can be mounted to the shaft, facing magnets supported on the hub to form an in-hub motor. When the load or RPM changes, the fluid pressure or movement in each bearing may change but the function of the bearing and its ability to provide stiffness and stability to the system will not be lessened.

In-hub spindle motor with separate fluid dynamic bearings

A disc drive actuator arm is an extended arm having forward edge to engage fluid flow due to rotation of the disc, a rear edge, and a top surface and a bottom surface along which fluid flows. The top and bottom surfaces join the forward and rear edges, and the fluid flow has a boundary layer along the top surface and the bottom surface. The arm has an aerodynamic cross-section so that the fluid flow boundary layer does not separate at the forward and rear edges. The fluid flow past the arm from the forward edge to the rear edge is substantially laminar to prevent vortex shedding.

Aerodynamically streamlined actuator arm for disc drives

A method of creating an improved hydrodynamic fluid bearing is provided which is relatively insensitive to shock vibration changes in load and rotational speed. The hydrodynamic bearing motor in which the bearing is open at both the upper and lower ends, and in which the balance of fluid flow within the bearings is maintained. The assembly of the hydrodynamic bearing is more easily assembled, and the gaps are easily adjusted. In the design of the hydrodynamic bearing, the tolerances for assembly of the various components is minimized; that is, the critical nature of many of the gaps is diminished.

Both ends open fluid dynamic bearing having a journal in combination with a conical bearing

A bearing assembly including a bearing cone (,) having a crowned bearing surface (,) with V-shaped grooves (,) that are shallow at their apex (,) and deepest at the outer edges (,). When mated with a female bearing seat, lubricating fluid builds up along the midline of the bearing surface as the bearing seat rotates about the bearing cone.

Crowned conical bearing

An improved capillary seal for use with a hydrodynamic bearing is disclosed, which provides a stronger or stiffer seal for a fluid dynamic bearing motor which is open at both ends, and is used with top cover attached motors utilizing fluid dynamic bearings. The design of the capillary seal uses centrifuigal force to actively push the oil back into the FDB while it is spinning, combined with the capillary tension which holds oil in the FDB during stationary periods. Also, the seal design comprises two walls which converge toward an apex near an adjacent fluid dynamic bearing. This design allows air, trapped within the seal and the associated FDB, to be expelled, eliminating air bubbles from the fluid dynamic bearing.

Centrifugal capillary seal for use with fluid dynamic bearings

A hydrodynamic bearing useful as a bearing cartridge or as the cartridge may be incorporated into a spindle motor or the like, where the bearing includes a stationary shaft and two independent bearings, comprising a top cone and a bottom cone separated by a segment of the shaft. The bearing includes a sleeve rotating around and surrounding the shaft, and the top cone and bottom cone and defining a narrow gap between the sleeve and the shaft and cones. Sealing plates are supported on the sleeve to seal off the ends of the bearing and are located along the shaft beyond the cones. A gap also exists between an interior surface portion of each cone and the shaft. Thus, separate flow paths are established, one around the top cone and one around the bottom cone. By providing two independent paths, the flow rates do not have to be the same in each conical flow path for the bearing seals to function properly.

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San Jose, CA, United States of America

Mohamed Mizanur Rahman