Pressure Pile Driver, Dual Relief Valve Hydraulic System Pressure Building Process Failure Analysis And Dynamic Characteristics

Among the equipment of pile construction, hydraulic static pile driver has its prominent advantages such as low noise, small vibration and non-pollution. Therefore, it is widely used. With the tonnage accretion of the hydraulic static pile driver and the flow increase in the hydraulic system, the old single unloading relief valve cannot meet the requirements of unloading system. Consequently at present the largest tonnage of static pile driver hydraulic system often adopt the dual overflow valve to unload, however, in practical work when the pile driver with more system flux from the unloading state switches to working conditions, there is often a problem of being unable to establish a system pressure, seriously affected the normal working of the pile driver.In view of this question, according to the common reason of hydraulic system abnormal pressure, this paper first analyzed the breakdown lies in the forerunner type overflow valve main valve core unable to act normally. Then after the double overflow valve discharge presses in the system the position discharge, the thesis made use of the power linkage chart and Matlab/Simulink as the modeling and simulation tool to carry on the dynamic characteristic simulation analysis on the process of establishing the system working pressure, obtaining the breakdown reason: There is mutual influence relations between the double overflow valve; The main valve core high and low cavity fat liquor's pressure difference, the stable state fluid power's size is big to the main valve core movement's influence and other reasons.Finally, according to the breakdown reason, the paper proposed to change the overflow valve 2 damping hole size and the overflow valve 2 recoil check spring's precompression quantity, put forward the solution based on the system return route. It carried on the simulation analysis to the solution, elaborating the good and bad points of each plan. The paper also has carried on the field test to the feasibility of each plan, thus proposing solution of the problem that double overflow valve is unable to establish the system pressure.