Axial flow fluid compressor with oil supply passage through rotor

Abstract

A compressor having a cylinder and a cylindrical rotational body housed within the cylinder. A spiral groove is formed in the outer peripheral surface of the rotational body, and a spiral blade is fitted in the groove so as to be freely retreated in and projected from the groove in the radial direction of the rotational body. The cylinder and the rotational body are rotated relative to each other by a drive mechanism. A fluid to be compressed is introduced into working chambers defined by the blade, the inner peripheral surface of the cylinder and the outer peripheral surface of the rotational body. The fluid is first guided into the first working chamber from a gas suction port, and then into the second and subsequent working chambers successively, whereby the fluid is compressed. An oil supply mechanism supplies pressurized oil to an oil supply hole formed in the rotational body. The oil supply hole communicates with that area of the bottom of the spiral groove, which corresponds to the position where the second and subsequent working chambers begin when the suction stroke of the first working chamber ends. The pressurized oil urges the outer peripheral surface of the blade onto the inner peripheral surface of the cylinder.