Rolling piston type rotary machine with discharge passage in vane

Claim 1

A rolling piston type rotary machine comprising: a cylinder having a cylindrical inner peripheral surface, a rotor disposed in said cylinder in eccentric relationship to the axis of said cylinder and mounted for revolution in rolling contact with said cylindrical inner peripheral surface of said cylinder, said cylinder being formed therein with a vane chamber having an inner part open substantially radially in said cylindrical inner peripheral surface of said cylinder, said cylinder and said rotor cooperating to define therebetween a generally crescent-shaped space movable about the axis of said cylinder by the revolution of said rotor, a radially inwardly biased vane slidably mounted in said vane chamber and having an inner end in slidng contact with the outer peripheral surface of said rotor so that said vane is reciprocally moved as said rotor is revolved, said vane dividing said crescent-shaped space into a suction chamber and a discharge chamber, said vane chamber having an outer part into and out of which said vane is reciprocally moved, said cylinder being further formed therein with a suction port adapted to be open to said suction chamber and a discharge port communicated with said outer part of said vane chamber, said inner part of said vane chamber and said vane being so shaped as to define therebetween a substantially radial communication passage through which said discharge chamber is adapted to be communicated with said outer part of said vane chamber, said communication passage being so arranged that the communication between said discharge chamber and said outer part of said vane chamber is interrupted at least when the point of contact between said rotor and said inner peripheral surface of said cylinder reaches said vane, said vane being provided with at least one groove formed in a side of said vane, said groove cooperating with a mating wall of said inner part of said vane chamber to provide said communication passage, said groove being shaped such that the cross-section of said communication passage is gradually increased at a substantially constant rate as said vane is moved out of said outer part of said vane chamber.