Design of a milling cutter for a novel three-lobe arc-cycloidal helical rotor

Abstract

This paper focuses on the design of a milling cutter for machining the arc-cycloidal helical rotor of a Roots blower. The milling cutter is developed on the basis of a novel rotor of a Roots blower which consists of both concave and convex arcs and a cycloidal curve in the transversal section. The geometric analysis of the transverse section and the helical tooth profile for the proposed rotor are presented. The paper reveals the contact characteristics between the cutter and the rotor blank being machined and derives the normal vectors of three different tooth sections. The paper further develops equations of the contact line for the conjugate motion of the cutter and the rotor blank and presents a design methodology of the milling cutter. The interference in the machining process is then investigated and numerical results are produced. The results from the analysis demonstrate that there is no interference in the machining using the developed cutter. The developed cutter is then demonstrated in the end of this paper in machining the novel arc-cycloidal helical rotor with three lobes.