Abstract:  Whether the parameter matching of the valve was appropriate and the structure was reasonable determines whether the designed proportional pressure reducing valve could meet the required performance requirements. Aiming at the parameter selection and structure optimization of the high pressure drop proportional pressure reducing valve in the design process, the basic performance, step characteristics, current-pressure characteristics and internal flow characteristics of the valve were studied. Firstly, the amount of valve cover and the opening under the limit condition were obtained through the theoretical calculation. The damping hole diameter and spring stiffness were selected based on the step response characteristics, the theoretical step characteristic curve and the current-pressure characteristic curve of the proportional reducing valve were obtained. Then, the state of the valve under the extreme working conditions was analyzed, and the structure of the pressure reducing valve was optimized in view of the situation. Finally, in order to accurately display the valve‘’s input current signal and output pressure fluctuations, and detect its step characteristics and current-pressure characteristics,a test system was built to test the optimized proportional pressure reducing valve. The experimental results show that when the damping hole is 2mm and the spring stiffness is 25N/mm, the pressure reducing valve has good step characteristics and current-pressure characteristics; reasonably increasing the diameter of the undercut groove of the valve body and increasing the bevel and fillet at the step of the valve core can effectively improve the performance of this pressure reducing valve.
Key words:  hydraulic transmission; parameter matching; step characteristics; currentpressure characteristics; internal flow characteristics; structural optimization; damping hole diameter; spring stiffness