Abstract: A compressor includes a casing having an oil reservoir, a cylinder situated within the casing, a cylindrical rotary body situated eccentrically within the cylinder, the rotary body having first and second spiral grooves extending in opposite directions from the middle part of the rotary body to both ends of the rotary body, first and second spiral blades fitted in the first and second spiral grooves, the blades having outer peripheral surfaces brought into contact with the inner peripheral surface of the cylinder, dividing the space defined by the inner peripheral surface of the cylinder and the rotary body into a plurality of working chambers, thereby constituting first and second compression sections, wherein the first and second blades freely project from and retreat in the first and second spiral grooves in the radial direction of the rotary body, driving means for rotating the cylinder and the rotary body relative to each other, a first refrigerant passage formed in the rotary body and opening to an area

Abstract: A compressor includes a cylinder, and a rotating body located in the cylinder, and a helical groove formed on the outer periphery of the rotating body. A helical blade is fitted in the groove and divides the space between the inner periphery of the cylinder and the outer periphery of the rotating body into operating chambers which have volumes gradually decreasing with distance from one end of the cylinder. The helical blade has dimensions satisfying the following formula:(1+.mu..sup.2) (.alpha./.beta.)<(L+.mu.B)in whichB: axial width, T: radial height, L: exposed height, and .mu.: frictional coefficient, and in which.alpha.=(B.sup.2 +2TL-L.sup.2)/2 +{-B.sup.2 (1-.mu..sup.2)+.mu.BT+.mu..sup.2 TL}/(1-.mu..sup.2).beta.=T-L+{.mu.B(1+.mu..sup.2)+(2.mu.(.mu.(.mu.T-B)}/(1-.mu..sup.2).