F-0324 Analysis for Polygonal Error of Screw Rotor which is Cut by Using the Hob

Abstract

A precise analysis has been made for the polygonal error of the screw rotor which is cut by using the hob. Firstly, in case that the cutting edge profile of the hob is given as a series of dispersive points, theoretical equations are derived to represent the profile of the screw rotor which is cut by using the hob. Secondly, a theoretical analysis is made to obtain the polygonal error of the screw rotor by using these equations. Thirdly, a numerical analysis method is proposed to obtain the polygonal error of the screw rotor. Finally, the theories in this analysis are verified by applying the numerical analysis method to the dimensions of the screw rotor hobs.