Abstract: Analyzes the adjusting principle and structure of the 3-way flow valve.The 3-way flow valve is used in the quantitative pump load sensing hydraulic system.The analytical model of the damping hole’s characteristic is built and mathematical model of cavity’s dynamic-pressure is established in the process of the 3-way flow valve having a load sensing.Then the main structure parameters of the 3-way flow valve is simulated by Matlab software.Those structure parameters can influence the pressure’s variation.It concludes 4 parameters can affects the 3-way flow valve’s left-pressure in different ways.The damping hole’s diameter,the damping hole’s length,the left cavity,the valve core’s flow-gain of the 3-way flow valve are analyzed.The conclusion that when designing the 3-way flow valve,the damping hole’s size,the left cavity’s structure,the valve core’s shape should be suitable is produced.This work may offer some theoretical basis for the 3-way flow valve’s design which used in the quantitative pump load sensing hydraulic system.

Key words: quantitative pump, load sensing, 3-way flow valve, characters’ analysis