Construction and Performance Study of a Novel Eccentric Involute Asymmetric Rotor of Roots Vacuum Pumps

As important part of Roots vacuum pump, Roots rotors have great influence on the performance of Roots vacuum pumps. In order to solve the problem that the traditional involute rotor has an unsmooth connection point between the involute and the arc, which leads to increased leakage and decreased operation efficiency, an eccentric involute asymmetric rotor is proposed in this paper by using eccentric involute to smoothly connect the tooth top and tooth root arc. The geometric model of the eccentric involute asymmetric rotor is established, and the effect of profile parameters on area utilization ratio is analyzed. Results show that with the increase of central angle and the decrease of pitch radius, the rotor area utilization ratio increases; compared with the traditional involute rotor, the displacement per revolution of the eccentric involute asymmetric rotor is increased by 17.2%, the outlet flow pulsation is reduced by 9.8%, and the outlet pressure pulsation is reduced by 7.9%. The research content is of great significance to the development of Roots vacuum pumps.