Patent ID: 7553141

Claim:
A rotary fluid machine comprising: an eccentric rotary piston mechanism including a cylinder having an annular cylinder chamber, an annular piston housed in an eccentric fashion relative to the cylinder in the cylinder chamber and dividing the cylinder chamber into an outer cylinder chamber and an inner cylinder chamber, and a blade disposed in the cylinder chamber and dividing each of the outer and inner cylinder chambers into a first chamber and a second chamber, the cylinder and the annular piston relatively executing eccentric rotary motion; a driving mechanism for driving the eccentric rotary piston mechanism; a casing configured to house the eccentric rotary piston mechanism; and a coupling member by which the annular piston and the blade are mutually movably coupled together, the cylinder being provided with the blade, the coupling member having a first sliding surface against the annular piston and a second sliding surface against the blade, and the outer cylinder chamber being formed on an outside of the annular piston and the inner cylinder chamber being formed on an inside of the annular piston differ from each other in suction shutoff angle, a suction shutoff angle of the outer cylinder chamber being greater than a suction shutoff angle of the inner cylinder chamber.