Dynamic analysis of main control valve reversing performance for hydraulic pile hammer

To make hydraulic pile hammer work at high frequencies when control system rapidly reverses,the main control valve was designed to realize the flexible control of the system with rapid reversing.The spool movement was controlled by pressure variation on four ports and the state of spool movement was remembered through inner feedback hole.According to the working principle of main control valve,the dynamic mathematic model of main control valve reversing was established.Using Stateflow to manage the state transfer of spool movement,the simulation model was presented in combination with Simulink.The simulation was done with parameters in the experiment and the reversing time required is in accord with the results of experiment.The effects of main parameters to reversing performance of main control valve were analyzed.The results show that inner chamber diameter has the greatest effects on reversing performance,the diameter of feedback hole was the second,the length of the feedback hole follow and the spring stiffness is the smallest.