Scroll type fluid machine with an involute spiral based on a circle having a varying radius

摘要

A scroll type fluid machine including two scroll members, each having a spiral body formed on a base plate, which are arranged to make their spiral bodies mesh with each other to form a confined space therebetween, one of said scroll members being arranged to make an orbiting movement relatively to the other scroll member to successively enlarge or reduce said confined space to expand or contract a fluid confined in said space, wherein said spiral body has a shape formed by an involute based on a circle having a radius which varies in accordance with an involute angle.