A New Design Method for the Rotor Profile Curve of the Cam Pump

Abstract

The cam pumps are especially suitable for the transmission of the liquids with different impurities or pure solid materials. A new design method for the rotor profile curve of the cam pump was put forward to improve the wear-proof of the addendum of the rotors. A rotor with a simple profile curve was designed and then the profile curve of another rotor would be generated by a tool whose cutting profile curve was the same as the designed rotor profile curve. This method was stated and a mathematic model was built based on gear meshing theory by choosing an ellipse as the designed rotor profile curve. The influence of the design parameters on the generated rotor profile curve, the area utilization coefficient of the pump and the relative normal curvature of the two profile curves at the contact points were analyzed. The results demonstrated as: the designed profile curve can be some kind of simple continuous curve and the generated profile curve is continuous curve as well; the area utilization coefficient, C, increases by increasing the major semi-axis of the ellipse, a, or decreasing the minor semi-axis, b, if the designed profile surface is an elliptic one; the maximum of the area utilization coefficient, Cmax, will decrease when the blade number of the rotor 2, z2, increases because of the undercutting; the maximum of the area utilization coefficient is 0.48 when z2 is 2; the blade number of the rotor 2 is no more than 4.