Abstract:Aimed at the presence of vibration and noise problems in gear pumps, a new structure of multi-gear variable gear pump was proposed. According to theoretical analysis on flow characteristics, the MATLAB software was used to program the instantaneous flow characteristic for simulation analysis. The results show that as compared with normal external gear pump, not only the displacement can be changed by the variable pump, with which the instantaneous flow increased significantly and flow pulsation enormously reduced, but also the effective control is realized of the pump vibration and noise, with good flow characteristics quality.