Abstract: In order to solve the key questions, wrap profile construction and profile modification for multi-wraps scroll machinery, the model of orbiting central position is presented, the generation characteristic and motion meshing law of multiply wraps on two scroll plates are determined, the mathematic model of meshing profile construction for multi-wraps with random wrap numbers is established, the conditions of common curves being used for meshing profile for multi-wraps are given, and the construction criteria of meshing profile for multi-wraps are obtained. The study results lay theoretical foundation for directly constructing new meshing profile which can realize correct meshing. The new multi-wraps profiles such as regular polygon involute, combination profile as well as tapered thickness wrap profile are proposed, and the new multi-wraps profile modification methods including arc profile modification method, circle involute profile modification method and combination curve profile modification method are proposed, too. The theory system of multi-wraps meshing profile including the existing single wrap profile is established.

Key words: Construction criteria, Meshing profile, Multi-wraps, Scroll machinery, Wrap profile modification