Gas compressor with variably biased vanes

A gas compressor comprising:

• a cylinder having side blocks attached to its end surface;
• a rotor rotatably disposed within the cylinder;
• vanes which slide within a vane groove formed on an outer peripheral surface of the rotor and which is arranged so as to be projectable from the outer peripheral surface of the rotor toward an inner peripheral surface of the cylinder;
• a compression chamber constituted by a small chamber that is partitioned off and defined in the interior of the cylinder by the cylinder, the side block, the rotor, and the vanes, which alternately increases and decreases in volume as the rotor rotates, and sucks in a refrigerant gas in a low-pressure chamber due to the volume variation to compress and then discharge it into a high-pressure chamber side;
• a scoop groove with which a bottom portion of the vane groove communicates during a suction and compression process of the refrigerant gas and from which a vane back pressure is supplied into the bottom portion of the vane groove;
• a high pressure supply hole with which the bottom portion of the vane groove communicates at a time immediately before discharge of the refrigerant gas and from which a vane back pressure having a pressure higher than the vane back pressure supplied from the scoop groove is supplied into the bottom portion of the vane groove;
• and
• a pressure control valve which interconnects the scoop groove with a low-pressure chamber side when there has occurred a reversed pressure relationship between the low-pressure chamber and the high-pressure chamber, wherein
• the scoop groove and the high pressure supply hole are arranged so as to be spaced apart from each other, and an interval therebetween is set to an interval sufficient to ensure that the vane groove is communicated with neither the scoop groove nor the high pressure supply hole.