Air-supported bearing for turbine engines

In a thermal turbine engine having a ceramic rotor, having a cylindrical shaft, adapted to rotate at high rotational speeds, a bearing comprising an air-supported bearing, said air-supported bearing including an outer bearing ring and an inner bearing ring, and a lubricating air film being maintained intermediate said bearing rings, the improvement comprising:

• said inner bearing ring including a convex spherical outer surface and said outer bearing ring including a concave inner spherical surface substantially complementary to and positioned adjacent said convex outer spherical surface with a spherical fluid gap existing between the convex and concave surfaces, said inner bearing ring also including a cylindrical inner surface substantially complementary to and positioned adjacent to the outer cylindrical surface of said cylindrical shaft with a cylindrical gap existing therebetween, and the materials of said inner bearing ring and the shaft of said ceramic rotor being selected so that the cylindrical gap between said shaft and said inner bearing ring remains substantially constant over the entire temperature range and rotational speed range of said turbine engine, and the diameters of said shaft and said inner bearing ring being dimensioned relative to each other so that a friction contact exists between said inner bearing ring and said shaft at lower rotational speeds of said engine whereas a dynamic lubricating air film is produced intermediate said shaft and said inner bearing ring at higher rotational speeds.