Abstract: A shaft having a thrust plate at or near one end, and a sleeve cooperating with the shaft to define one or more journal bearings and a counterplate (which may be supported by the sleeve or defined by the sleeve) defining at least one counter thrust surface in cooperation with the thrust plate. In order to maintain an enhanced fluid distribution across the journal bearing and maintain pressure distribution boundary conditions as desired, one or more grooves are defined along the shaft extending behind or between the thrust plate and the shaft. The grooves typically extend from one radial side of the thrustplate behind the thrustplate and up to a point on the shaft adjacent or nearly adjacent to one of the journal bearings. Alternatively, the slot or slots may extend to a point between two journal bearings.

Abstract: 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.