Surface Modelling and Design Approach for a Multiple Cone Screw-bush Pair

To improve the carrying capacity and the flow stability of the screw pump and to solve the problem of cavitation generated by oil and gas leakages,a surface forming method was investigated based on the multiple column screw and single cone screw theory. An equation of the cone screw-bush pair surface was established according to the space engagement theory. A flow equation of multiple cone screwbush pair was built up based on the cone screw-bush pair sectionequation and the rule of its variation.The calculation method of the screw structure size at a given flow rate was determined as well. A kinematics equation of the multiple cone screw-bush pair was obtained after a through kinematics analysis of the multiple cone screw-bush pair was conducted. The movement rule of a multiple cone screw-bush pair was summarized. A cone screw and a bush solid model were processed based on the 3D model of the cone screw-bush pair and the 3D printing technology. The correctness of the kinematics equation about multiple cone screw-bush pair was verified. Moreover,the motion simulation of the pair was conducted by using pro/mechanism and the kinematics rules were verified at the same time.