Patent ID: 8568119

Claim:
A single-screw compressor configured to compress a fluid in a compression chamber, the single-screw compressor comprising: a screw rotor including a spiral groove formed in a spiral pattern on an outer circumferential portion thereof; a casing accommodating the screw rotor; and a gate rotor including a plurality of gates formed in a radial pattern, the gates being configured and arranged to mesh with the spiral groove of the screw rotor, the compression chamber being defined by the screw rotor, the casing and the gates such that the fluid is compressed in the compression chamber when one of the gates relatively moves from a start end of the spiral groove toward a terminal end of the spiral groove in the spiral groove, in the spiral groove, a discharge side portion is a portion extending from a predetermined position of the spiral groove at a certain point in a compression phase to the terminal end thereof, and a suction side portion is a portion other than the discharge side portion, a clearance between a side wall surface of the suction side portion and a side surface of the gate is constant, a clearance between a side surface of the gate and a side wall surface of the discharge side portion of the spiral groove being larger than a clearance between the side surface of the gate the side wall surface of the suction side portion of the spiral groove, and the clearance between the side wall surface of the discharge side portion of the spiral groove and the side surface of the gate gradually increasing as the gate disposed in the spiral groove comes closer to the terminal end of the spiral groove.