Scroll type fluid machine having wraps formed of circular arcs

摘要

The present invention enables a scroll fluid machine to have a maximum design volume ratio without increasing an outside dimension of scrolls and allows the basic spiral curve of the scroll to be configured with simple curves. The basic spiral curve of a scroll wrap comprises a group of concentric semicircles, a group of circular arcs having a center different from that of the group of semicircles, and a group of straight lines or curves connecting the group of semicircles and the group of circular arcs together, and a diameter of the outer-most circumferential semicircle of a fixed scroll member is twice as large as radius of the outer-most circumferential circular arc of an orbiting scroll member. In addition, an outer diameter of an end plate of an orbiting scroll is equal to an outer diameter of the outer-most circumferential wrap of the scroll.