Abstract: An improved foil thrust bearing includes a pair of members arranged for relative rotation with respect to one another. One of the pair of members is adapted to rotatably support the other. A thrust bearing disk is operatively disposed between the pair of relatively rotatable members. The thrust bearing disk has a plurality of diverging surface ramps. The surface ramps can comprise an inner ramp and an outer ramp. The thrust bearing disk can also comprise a plurality of radial slots. A plurality of separately formed, converging surface compliant foils are disposed on the thrust bearing disk and between the ramps. An underspring element is operatively disposed between the thrust bearing disk and one of the rotatable members, with the underspring element having a plurality of alternating upper and lower ridges.

Abstract: An improved foil thrust bearing having a thrust runner and a thrust plate includes an underspring element positioned adjacent to the thrust plate. The underspring element comprises, in one embodiment, a plurality of alternating first apertures and spring portions, with at least one spring portion having a periodic configuration and comprising a leading edge and a trailing edge. The periodic configuration is defined by a plurality of pitches that vary between the leading and trailing edges. Also defining the periodic configuration is a plurality of periodic elements that vary in longitudinal length between the leading and trailing edges. A thrust bearing disk is disposed intermediate the underspring element and the thrust runner. The disk comprises a plurality of transition areas that provide a stepped configuration to the disk. The transition areas match a plurality of circumferential positions of the first apertures in the underspring.