| 摘要 |
PURPOSE:To stabilize the movement of a rotor and to keep the level and the direction of bearing load constant, by providing a balance piston at one end of a rotor shaft so as to urge the rotor from the discharge side to the suction side by a constant force througout the entire operation of a compressor. CONSTITUTION:In starting operation of a compressor, pressure is acted in a second chamber 30 in a cylinder 28 of a balance piston 27 via a second oil pressure control valve 2, pipe 47 and port 32, so that a male rotor 13 is imparted with a force urging the same from the discharge side to the suction side of the compressor. During full-load operation of the compressor, on the other hand, pressure is acted in a first chamber 29 in the cylinder 28 via a first oil pressure control valve 41 pipe 46 and port 31, so that the force urging the male rotor 13 from the discharge side to the suction side is kept at a proper level. Further, when the mode of operation of the compressor is switched from full-load operation to no-load operation, pressure in the first chamber 29 is lowered, so that the force urging the male rotor 13 from the discharge side to the suction side is kept constant. |
