Abstract:The piston rod is an important component of a large diaphragm pump, and its weight affects the sealing performance of the piston. A high-quality piston rod can easily cause a large force on the bottom of the piston sealing ring, and the top seal is not tightly sealed, resulting in piston seal leakage or even failure, affecting the operational performance of the diaphragm pump. In order to reduce the weight of piston rod of diaphragm pump and its influence on the sealing performance of piston, and improve the efficiency of diaphragm pump, a new type of lightweight piston rod was designed based on the piston rod of a certain type of diaphragm pump, and the new piston rod with different structure parameters is simulated. The results show that necking diameter D and fillet radius A have the greatest influence on the maximum equivalent stress of piston rod, and the maximum equivalent stress decreases with the increase of necking diameter D and fillet radius A The influence of inclination angle B and fillet radius C angle on the maximum stress is not obvious.