Analysis of Rotor Contact for Screw Compressor(<Special Issue>Micro Mechanical Engineering)

A reliability evaluation of meshing rotor surfaces needs contact theory on a micro size area. We propose a method to evaluate whether a screw compressor rotor has enough contact fatigue strength. The method is based on analyses of three dimensional curvatures and the Hertz contact pressure. At a contact point one of the principal curvatures directs the rotor's sealing line and this is calculated as the gap distribution. Another perpendicular curvature is calculated with an approximate arc to the rotor profile. As the contact point is an inflection point, the contact condition is first calculated on each side and then composed. Using our method we found the rotors of a typical screw compressor have enough strength. This is because the rotor contact pressure is calculated to be 0.57 times of a contact fatigue strength of their material.