Research On Anti-shock Mechanism And Experiment Of Load-sensing Hydraulic System

The huge hydraulic shock that the main flow control valve closing suddenly affects the life of hydraulic components and the stability of the load-sensing system,there is an urgent need to study the hydraulic shock mechanism and anti-shock method to improve the stability and reliability of the the load-sensing system.This paper targets a load-sensitive system and mainly studies the influential factors and the anti-shock method of the load-sensing system.1)A mathematical model was established based on high shock of the load-sensing system,the main factors that affecting stability of the load-sensitive system were analyzed.The main reason for the pressure shock in load sense hydraulic system was by the main flow control valve closing for the pump displacement changing lag,a method to reduce the shock by releasing excess flow of the pump was proposed with anti-shock valve.2)Simulation on the A10 VSO Rexroth load-sensitive pump was done with AMESim,the effect of the main valve closing time,flow,load pressure,pipe length and diameter were researched in the load-sensitive system.The results indicate that the pressure shock was related to the main valve closing time,flow,the pipe length and diameter independent of load pressure in the load-sensing system.The pressure shocks basically disappeared after the closing time of main flow control valve got to 900ms;the shock pressure increased with the increase of flow;the pipe length and diameter was increased would reduce pressure shock,but the response time of the system was relatively delayed.3)According to the proposed flow elimination method,the anti-shock test bench was built by using the M4-12JW2-V01 chip high-pressure multi-way valve,the test bench based on self-made measurement system with LabVIEW and CAN bus were constructed to research on shock characteristics of hydraulic system at different load pressure,flow and main flow control valve closing speed.The results indicated that the closing time of main flow control valve between 1~900ms made system produce shock,after which the shock would basically disappear;when the flow rate increased 10L/min in the load-sensing system,the pressure shock growth rate was 23.94% in the 50 ms of the main valve closing speed.Within the matching flow range,the system pressure shock was below 10% compared to the maximum shock 65% without anti-shock valve.The anti-shock valve can not only improve the stability of the system but also verify the correctness of the simulation results and the effectiveness of the proposed method.The proposed method based on flow elimination and the results of this study can provide a reference method for the anti-shock load-sensing system.