Research On Pressure Response And Return Stroke Energy-Saving Characteristics Of Hydraulic System For Super CNC Plate Shearing Machine

Hydraulic system is a power system of the CNC machine, which provides shearing force to cut the sheet metal, and its standards and reliability have a direct influence on the maximum shearing force. According to recent researches in this field, one new hydraulic system is developed in this paper, which is suitable for cutting large span and thick plate. Moreover, the system pressure response and the return stroke energy-saving characteristics of the tool holder aided by accumulator are analyzed using numerical simulation and experimental methods. The main research contents are as follows:(1) A new hydraulic system for super CNC shearing machine is designed independently, which firstly used accumulator coupled with return cylinders to make the tool holder return. And it has remarkable energy saving effect. According to the analysis of system, the total pressure loss is 1.44 MPa, which meets the requirements of the hydraulic system and laid the foundation for the subsequent theoretical analysis.(2) Mathematical model and simulation model of the cartridge electromagnetic relief valve are established, and the boundary conditions of the simulation model are set up to analyze the system pressure and displacement of the main spool during the cycle working process. The research results show that the time consuming of building pressure is much longer than that of pressure relief, and pressure pulse is large when the system starts to unload. Moreover, the effects of structure parameters of the valve, input flow rate and working pressure on the system pressure response are analyzed comparatively.(3) The simulation model using accumulator to make the tool holder return is established. Then, the effect of initial inflation volume and effective area of liquid chamber of the accumulator on the return stroke energy-saving characteristics are analyzed. The larger of them, the more slowly return response is. Finally, the energy consumption of two balance model is compared. It is found that the energy consumption of the system using accumulator is reduced by 14.8%.(4) The hydraulic experiment system is built up, and its experimental scheme to study system pressure response is carried out. Static unloading pressure and pressure response characteristics of the cartridge electromagnetic relief valve are investigated. The experimental results show that with the increase of the input flow rate, the unloading pressure can increase to a certain extent, at the same time, the pressure pulse also increases. The experimental results are consistent with the previous, which verifies the correctness of the theoretical analysis.