Apparatus for eliminating whirl instability in a gas supported bearing

A gas-supported bearing assembly comprising:

• a. a cylindrical bearing sleeve having a longitudinal axis and a cylindrical inner surface including a first bearing surface;
• b. a cylindrical bearing shaft positioned coaxially within the bearing sleeve, separated from the bearing by a gaseous medium, and having a cylindrical outer surface including a second bearing surface, wherein a relative rotational velocity is established between the bearing sleeve and the bearing shaft to generate a bearing supporting force through the gaseous medium along a bearing overlap zone where the first bearing surface overlaps the second bearing surface but is separated from the second bearing surface by the gaseous medium to form first and second spaced apart gas bearings, the bearing overlap zone having a defined length along the longitudinal axis;
• and
• c. a pneumatic load ramp formed in one of the bearing surfaces creating a chamber between the first and second bearings and having a length along the longitudinal axis less than the length of the bearing overlap zone for generating a load in the gaseous medium within the camber to apply an asymmetric load through the gaseous medium in the chamber to the bearing assembly at a location fixed relative to either the sleeve or the shaft to eliminate bearing while instability, the first and second gas bearings restricting axial flow of the gaseous medium along the longitudinal axis into or out of the chamber.