Foil thrust bearing with varying radial and circumferential stiffness

Claim 2

A spring cluster disc for a foil thrust bearing; the disc defining an axis thereof and comprising a spaced, circumferentially extending plurality of spring sets in collectively annular positional relation; the sets being structurally adapted to provide stiffness variation such that, in a circumferential direction, both radial and circumferential stiffness first increases and then decreases.

Claim 3

The invention of claim 1 further comprising in combination with the disc: a plurality of substantially trapezoidal pads connected to the disc, each being overlaid on a respective spring set.

Claim 4

The invention of claim 1 wherein each spring set comprises a spring member having a plurality of slots formed therethrough; each slot having a respective radial dimension, and the stiffness variation being effected by variation in the radial dimension of the slots.

Claim 5

The invention of claim 3 wherein each spring set consists of the spring member.

Claim 6

The invention of claim 3 wherein the spring member is corrugated to form a plurality of corrugations; the slots being formed through crest of the corrugations.

Claim 7

The invention of claim 1 wherein each spring set comprises an arcuate spring member having a plurality of slots formed therethrough; the slots being arranged in a plurality of alignments thereof, each of the alignments comprising a respective number of the slots, and the stiffness variation being effected by variation in the number of slots in the alignments.

Claim 8

The invention of claim 4 wherein each spring set consists of the spring member.

Claim 9

The invention of claim 4 wherein the spring member is corrugated to form a plurality of corrugations, the slots being formed through crests of the corrugations.

Claim 10

The invention of claim 1 wherein each spring set comprises a spring member having a plurality of slots formed therethrough; each slot having a respective radial dimension; the slots being arranged in a plurality of alignments thereof; each of the alignments comprising a respective number of the slots, and the stiffness variation being effected by variation in both the radial dimension and number of slots in the alignments.

Claim 11

A foil thrust bearing, comprising in combination: a first disc having a plurality of foils connected thereto; a second disc coaxial with and having a surface adapted to face the first disc; the surface defining a dimensionally common plurality of spaced and arcuately extending trapezoidal regions; each region subtending an angle extending in a first circumferential direction from a respective first radial-line segment defining a respective first circumferential border of the region to a respective second radial-line segment defining a respective second circumferential border of the region; each region extending in a radial direction from a radially inner line defining a first radial border of the region to a radially outer line defining a second radial border of the region; the regions being registered with the foils as determined in a circumferential direction; and within each of the regions, a set of springs connected to or integral with the second disc; each set being configured to provide stiffness variation such that, in a circumferential direction, both radial and circumferential stiffness first increases and then decreases.

Claim 12

A foil thrust bearing, comprising in combination: a first disc having a plurality of foils connected thereto; a second disc coaxial with and having a surface adapted to face the first disc; the surface defining a dimensionally common plurality of spaced and arcuately extending trapezoidal regions; each region subtending an angle extending in a first circumferential direction from a respective first radial-line segment defining a respective first circumferential border of the region to a respective second radial-line segment defining a respective second circumferential border of the region; each region extending in a radial direction from a radially inner line defining a first radial border of the region to a radially outer line defining a second radial border of the region; the regions being registered with the foils as determined in a circumferential direction; and within each of the regions, a set of springs connected to or integral with the second disc; each set being configured to provide stiffness variation such that, in a circumferential direction, both radial and circumferential stiffness first increases and then decreases.