Patent ID: 7150610
Filing Date: 2006-12-19
Classification: F01C

Abstract:
1. A gas compressor comprising: a compressor main body which sucks, compresses, and discharges refrigerant gas, and an oil sump which stores oil for lubricating the compressor main body, the compressor main body being composed of a cylinder, side blocks disposed at axial ends of the cylinder, a rotor rotatably mounted to undergo rotation in the cylinder, vane grooves extending inwardly from an outer peripheral surface of the rotor toward an inner periphery thereof, and vanes slidable in respective ones of the vane grooves for slidably advancing and retracting during rotation of the rotor; a back pressure space including bottom portions of the vane grooves and attaining a middle pressure between a suction pressure and a discharge pressure during normal operation of the compressor main body; a first high pressure oil passage establishing communication between the oil sump and the vane groove bottom portions when the vanes are at their discharge stroke positions; a second high pressure oil passage establishing communication between the oil sump and the back pressure space; and an opening/closing valve for opening and closing the second high pressure oil passage.