The Pressure Discharge Impact And Its Reduction Technology Research Of Large Press

Abstract:Contraposed the4000t-die-forging press’s impact vibration and obvious noise in the process of pressure relief, with a great influence on the system reliability,the traditional pressure relief methods didn’t apply to electro-hydraulic proportional relief valve’s pressure relief system that was unique to the4000t-die-forging press.It needs to optimize unloading control mode to solve the problem of shock absorption and noise reduction in different load pressures without changing hardware.It derived ideal unloading pressure curve when unloading steadily by analysing pressure relief impact vibration mechanism of large press.It got the steadily unloading control mode by the relief system’s reverse simulation model of Simulink.It got steadily unloading control modes of other commonly used load pressures by the same method. Provided a reference for site unloading debugging.Main research contents are as follows.Firstly, analyzed the research progress of hydraulic impact’s improvement measures and ideal unloading curve,and analyzed its’pros and cons. Comparaed and studied several commonly used pressure relief plan, analyzed their optimization improvements and still existing problems. And studied the vibration mechanism of the pressure relief. Analyzed pressure relief impact mechanism caused by air pockets and the resonance phenomenonSecondly, It deduced stable pressure relief curves based on the impact essential characteristics of pressure relief. In order to deduce optimum unloading curve more comprehensively, respectively from the working cylinder compression, pressure relief valve’s flux and valve port’s flow velocity three angle were derived, And analyzed the three factors’s unloading curves that changed in sinusoidal and uniform two kinds of different situations.Identified using electro-hydraulic proportional overflow cartridge valve to pressure relief is the best pressure relief scheme.Thirdly, Put forward the reverse modeling and simulation analysis method, reversely model and simulate press’s pressure relief system by the derived pressure relief curves,obtained the proportional solenoid input voltage curve of electro-hydraulic proportional relief valve.And finally fitted the voltage signal mathematical expressions by the Matlab software.Fourthly, Experiments verified the correctness of the pressure relief system simulation model by contrasting simulation curve with experimental curve. It showed different conditions cannot adopt fixed unloading way by comparing the unloading experiment under different loading pressure,.It got ideal pressure relief curve’s unloading effect was more better and gentler to the default unloading way of the press by contrasting the advantages and disadvantages between ramp signals discharge pressure curve and the ideal unloading curve. Ideal unloading curve could be used to solve the4000t-die-forging press pressure relief’s impact problems.Finally, it derived the proportional electromagnetic valve input voltage of4000t-die-forging press in the other initial unloading pressure according to the reverse modeling and simulation method.Analyzed the key factors as well as the influence law affecting pressure relief.It provides theoretical reference of solving the impact problem of unloading for the future.