Patent ID: 8376722

Claim:
An electric compressor equipped with a motor unit, a rotary shaft rotated by the motor unit, a motor casing for axially supporting the rotary shaft, a compression casing provided to one end side of the motor casing, and an impeller provided to one end side of the rotary shaft and which rotates inside the compression casing, wherein: the rotary shaft is axially supported by a radial bearing in the motor casing in the rotational direction, and is supported by a thrust air bearing in an axial direction, the thrust air bearing includes a flange portion of a disk shape provided at an outer circumference in the diameter direction of the rotary shaft, a front thrust bearing provided in the front side of the flange portion, and a rear thrust bearing provided in the rear side of the flange portion, the front thrust bearing and the rear thrust bearing are fixed to the motor casing or the compression casing, and are each equipped with a top foil of a thin plate shape which faces both sides of the flange portion, and a bump foil of a corrugated plate shape which elastically supports the top foil, the flange portion is sandwiched by the front thrust bearing and the rear thrust bearing at a predetermined pressure, the motor casing includes a pressure chamber which introduces therein the pressure of gas generated by the rotation of the impeller, the rotary shaft is equipped with a load cancellation section which faces the pressure chamber and which receives pressure inside the pressure chamber in a direction opposite to the load in the axial direction generated by the rotation of the impeller, and wherein the pressure chamber is sealed by a side face of a canceller flange and a side face of an opening of a canceller casing, the canceller flange provided on an opposite side of the rotary shaft from the impeller.