Patent ID: 8347648

Claim:
A turbine unit used in an air cycle refrigerating/cooling system comprising: a first heat exchanger for cooling air; a turbine unit comprising: a compressor for compressing the air; and an expansion turbine for adiabatically expanding the air; a second heat exchanger for cooling the air, wherein the first heat exchanger, the compressor, the second heat exchanger, and the expansion turbine are cooperatively connected in series by an air path, and wherein a compressor rotor of the compressor and a turbine rotor of the expansion turbine are attached to a common main shaft in the turbine unit in such a manner that the turbine unit drives the compressor rotor with a power generated by the turbine rotor, and wherein the main shaft is rotatably supported by a rolling contact bearing, and wherein part or the entirety of a thrust force applied to the main shaft is supported by an electromagnet; and a pressure equalizing device for equalizing gas pressures at opposite ends of the rolling contact bearing comprising: (a) a first gap defined in a part of an outer surface of the main shaft between an inner ring of the rolling contact bearing and the main shaft, (b) a second gap provided between an outer ring of the rolling contact bearing and a first member in contact with the outer ring, or (c) a communication passage provided within the first member configured to make contact with the outer ring.