Displacement type fluid machine having rotation suppression of an orbiting displacer

A displacement type fluid machine, comprising:

• a closed vessel;
• a cylinder and a displacer provided between end plates in said closed vessel, said cylinder and said displacer being shaped wherein an outer peripheral surface of said displacer and an inner peripheral surface of said cylinder each have a shape comprising a plurality of volute portions formed by multi-arc shaped curves, and wherein the shape of the outer peripheral surface of said displacer is similar to but smaller than the shape of the inner peripheral surface of said cylinder such that when a center of said displacer and a center of said cylinder are aligned with each other, one space is formed by the outer peripheral surface of said displacer and the inner peripheral surface of said cylinder, and when said displacer is set to an orbiting position, a plurality of spaces are formed by an outer peripheral surface of said displacer and the inner peripheral surface of said cylinder;
• a drive shaft provided in said closed vessel and having a central longitudinal axis aligned with a central axis of said cylinder and having an eccentric portion on which said displacer is mounted to make an orbital motion around the central longitudinal axis of said drive shaft and the central axis of said cylinder;
• at least one rotation prevention mechanism comprising a pin member extending from said cylinder into a pin member receiving hole provided in said displacer, said pin member having an oil feed hole axially extending within said pin member;
• and
• a lubricating oil storage portion provided at a bottom of said closed vessel;
• wherein said oil feed hole communicates with said lubricating oil storage portion.