Patent ID: 8215898

Claim:
A turbine unit for refrigerating/cooling air cycle comprising a compressor, an expansion turbine, a main shaft, a rolling contact bearing for supporting the main shaft, an electromagnet for supporting part or the entirety of a thrust force applied to the main shaft, a sensor for detecting the thrust force and a controller for controlling a support force by the electromagnet in accordance with an output of the sensor, the compressor having a compressor rotor and the expansion turbine having a turbine rotor, the compressor rotor and the turbine rotor being attached to the main shaft so that the compressor rotor is driven by the power generated by the turbine rotor, or by a motor having a motor rotor attached to the main shaft, the sensor being interposed between a stationary outer ring of the rolling contact bearing and a spindle housing for supporting the stationary outer ring, and the sensor including sensor elements arranged in a circumferential direction of the main shaft, each sensor element having the properties changeable in accordance with a pressing force urged thereupon and capable of electrically detecting the change in the properties, thereby to detect the thrust force from an output of the sensor elements, wherein the sensor includes a plurality of magnetostrictors or super magnetostrictors arranged in the circumferential direction of the main shaft and detects a permeability of the magnetostrictors or super magnetostrictors thereby to detect the thrust force, and wherein the plurality of magnetostrictors or super magnetostrictors are sandwiched between two yolk members made of a soft magnetic material.