Research On The Novel Perfect Smooth Profiles Of Claw Rotors And Its Performance Characteristics For Claw Vacuum Pumps

The profiles of claw rotors affect the claw vacuum pump’s performance characteristics directly.In view of the problems that the existing claw rotor profiles contain non-smooth connection points of claw vacuum pumps,a novel perfect smooth profile of claw rotor is proposed in this paper,which is composed of 6 circular arcs and 3 equidistant curves of cycloid.The meshing relationship between each profile is analyzed,and the influence of the changed independent geometric parameters on the performance characteristics is studied.The three-dimensional numerical simulation of claw vacuum pump is realized,getting the distribution of flow field inside the working chamber,and the variation of mass flow rate and velocity vector in the meshing clearance and end clearance;the differences of the performance and mechanical properties are studied between the perfect smoothing claw rotor and the existing four claw rotors,revealing the advantages and disadvantages of different rotor performance during the claw vacuum pumps.The influence of the changed independent geometric parameters on the performance characteristics: the tip circular arc angel is larger,the relative clearance volume and the content ratio are smaller;the tip circular arc radius is larger,the relative clearance volume decreases first and then increases,the content ratio are smaller;the tip claw cusp circular arc radius is larger,the relative clearance volume is larger and the content ratio is smaller;the bottom claw cusp circular arc radius is larger,the relative clearance volume is smaller,the content ratio increases first and then decreases.Compared with the perfect smoothing claw rotor and the existing four claw rotors in the same geometric parameters,straight claw rotator has the smallest relative clearance volume and content ratio,circular arc curved claw rotor has the biggest relative clearance volume,the perfect smoothing claw rotor has the biggest content ratio and smaller content ratio,through the two performance parameters can be judged that the perfect smoothing claw rotor has better performance.The internal leakage of claw type vacuum pump working chamber mainly occurred in the two rotors’ meshing clearance and end clearance,and the force deformation of the rotor is mainly affected by the temperature,as well as the maximum value of the force and deformation in the mixing process.Compared with the perfect smoothing claw rotor and the existing four claw rotors in the same load,the mechanical property of straight claw rotor is the worst and perfect smoothing claw rotor is best.