A typical dynamic bearing design comprises a ring shaped or circular
thrust plate mounted at or near the end of a shaft, the shaft defining
together with a surrounding sleeve a journal bearing by providing grooves
on only one of the two surfaces facing the gap between the shaft and
sleeve. On the ring shaped thrust plate supported by the shaft, the
traditional upward thrust bearing defined between the lower face of the
thrust plate and the facing surface of the sleeve is maintained; but no
grooves are on the surface of the thrust plate distant from the shaft and
a facing counterplate surface. Further, the journal bearing is defined to
have an asymmetry so that a bias force pressure along the surface of the
shaft toward the thrust plate is established. The combination of the
journal groove asymmetry pumping action toward the shoulder or thrust
plate, together with the single grooved thrust bearing, is sufficient to
establish a constant pressure between the distal surface of the thrust
plate and the facing counterplate, as well as between the groove thrust
plate and the facing shoulder surface.