Research on the Calculation Method for the Envelope in Rotor Profile of Screw Compressor

The quality of the screw rotor profile has determined the performance of screw compressor.The arc,elliptical arc,parabola,straight line and cycloid could be expressed by simple parameter equation at present.But all these parameter equation's envelope couldn't be expressed by simple form because of the existence of the envelope conditions.Considering about that,in the actual design,the process of transforming the rotor's profile into the tooth of the cutter could be accomplished by a series of discrete points which is dense enough.So this paper proposes a route about calculating group of discrete points which belong to the parameter equation's envelope on the base of traditional theory.