In-hub spindle motor with separate fluid dynamic bearings

DETAILED DESCRIPTION Thus, it is an object of the present invention to create an improved hydrodynamic bearing which is relatively insensitive to changes in load and rotational speed.
Yet another objective of the present invention is to provide a hydrodynamic bearing motor in which the bearing is open at both the upper and lower ends.
A related objective of the invention is to provide a hydrodynamic bearing open at both ends in which the balance of fluid flow or pressure within the total system is maintained.
A further objective of the invention is to design a hydrodynamic bearing useful in a spindle motor or the like in which the motor could be attached to both the top cover and the base of the housing for the spindle motor.
Another objective of the invention is to provide a hydrodynamic bearing useful in a spindle motor or the like which is stiffer than known standard spindle motors which are supported only at one end.
Another objective is to provide a hydrodynamic bearing design having balanced internal fluid pressures during operation to minimize the likelihood of any lubricating fluid being lost during operation.
These and other objectives of the present invention are achieved by providing 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 shaft and two independent bearings, comprising a top cone or bi-sphere and a bottom cone or bi-sphere sphere separated by a segment of the shaft.
More specifically, 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