US 6,118,620 A · In-hub spindle motor with separate fluid dynamic bearings

Abstract

A hydrodynamic bearing system where the bearing includes a shaft and two independent bearings, comprising 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 said bearing element and said 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.

Claims20

Dependent claims

A spindle motor for use in a magnetic data storage system including a shaft having a central section and two independent fluid dynamic bearings on opposite sides of said central section,

each of said bearings comprising a bearing cone fixed to the shaft and tapering inwardly towards said central section, and a bearing seat rotating around the shafts each of the bearing seats having a fluid bearing surface which is complementary to a surface of said bearing cone to thereby establish a first section of a fluid dynamic bearing,
each of said fluid dynamic bearings further comprising a second gap section defined between an inner surface of said bearing cone and a surface of said shaft, and a third portion of a gap defined between a radially extending surface of said bearing cone and a complementary surface rotating with said bearing seat, so that a continuous gap is formed around each of said bearing cones, and
fluid in said continuous gap separating said complementary surfaces of said bearing seat and said bearing cone to allow free rotation of said bearing seat relative to said shaft and said bearing cone and a centrifugal capillary seal on one side of each said bearing cone and a grooved pumping seal on the opposite side of each said bearing cone to isolate and contain said fluid within said independent fluid dynamic bearings.

A magnetic disc storage system comprising:

a base,
a rotatable magnetic storage disc having an axis of rotation,
a transducing head for reading and writing information on the disc,
a fixed shaft supported in said base having a central section supporting a stator, and
independent fluid dynamic bearings on opposite sides of said central section of said shaft located near to said base and distant from said base on the opposite side of said stator,
said fluid dynamic bearings each comprising a generally conical bearing member supported from said shaft and having a generally conical surface extending inwardly toward said central section of said shaft and cooperating with a complementary generally conical face of a bearing seat,
said bearing seats extending generally radially away from said shaft beyond said stator and supporting a hub, a magnet aligned with said stator, activation of said stator causing rotation of said hub,
rotation of said hub being supported by lubricating fluid in first and second gaps defined between said generally conical surfaces of said conical bearing members on said shaft, complementary surfaces on said bearing seat and a centrifugal capillary seal on one side of each said bearing and a grooved pumping seal on the opposite side of each said bearing to isolate and contain said fluid within said independent fluid dynamic bearings.

5 more elements

Dependencies are inferred from the claim text.

In-hub spindle motor with separate fluid dynamic bearings

Life of this patent

In-hub spindle motor with separate fluid dynamic bearings

Life of this patent

Abstract

Claims20