Based on the fluid dynamic characteristics of gear pump

a robust design method was proposed to solve the large noise

low volume efficiency in external gear pump caused by high pressure of trapped oil. A type of high pressure gear pump was used as the research object

modeled and simulated by CFD professional software PUMPLINX. The effects on trapped oil pressure by cat eye type unloading groove structure parameters

gear pump speed

load pressure and medium characteristics were analyzed. An approximate model of trapped oil pressure was built based on the design of experiments and response surface function methods. Finally

in order to reduce the impact of uncontrollable of factors such as pump speed

load pressure and medium characteristics on pump performance

the robust performance evaluation model was built to optimize the cat type unloading groove structure parameters and achieve the trapped oil pressure model subjecting to normal distribution in the case of the minimum mean square error. Besides

with the change of random and uncontrollable factors

the robust performance of trapped oil pressure was verified; the result displayed that the trapped oil pressure peak before robust design fluctuated from 40% to 18% after robust design

so the stability and reliability of working pump were improved.