Abstract:The mixed highorder Fourier noncircular geardriven differential pump has some performance indexes such as discharge, flow pulsation and the maximum modulus of noncircular gear undercut which have many complex influential factors. In order to obtain the best parameters, the basic relations between the order of Fourier noncircular gear and parameters of vanes were established. The mixed highorder Fourier noncircular gear transmission model was built. The subobjective functions of displacement and flow pulsation, and the maximum modulus of noncircular gear undercut were presented. The target evaluation function using the efficacy coefficient method was put forward. And then the multiobjective optimization method was designed based on genetic algorithm to obtain noninferior solutions when the mixed highorder Fourier noncircular geardriven differential pump has the maximum capacity and the minimum pulsation rate which meets the requirement that the maximum modulus of noncircular gear undercut was more than 1.5 in the same pump cavity size. The flow pulsation rate of the optimized differential pump was 22.04% and the displacement was 3870.44mL. Thus, the flow pulsation rate was decreased by 11.3% and the displacement was increased by 3% compared with the existed study.