| Hot pressing hydraulic press is a kind of press which presses the iron and steel sheet which is heated to austenite,closes the mold quickly and keeps the pressure,making it into a fixed shape.Compared with the traditional cold press hydraulic press,its processed parts have high strength,good formability,lighter weight under the condition of meeting the mechanical properties of parts,in line with the national energy conservation and emission reduction policy,welcomed by major automobile manufacturers,with broad application prospects and development potential.Firstly,according to the load characteristics of the hot forming workpiece,the hydraulic system of the hot forming machine is designed,which is characterized by the combination of the main loop and the accumulator loop for liquid supply,which can realize the working speed under three required working conditions.In view of the excessive energy consumption of the press system when 5 cylinders are pressurized in parallel,the working mode of graded compression is designed.Due to the structural defects of the original oil tank of the press,the hydraulic press has deformation of the high oil tank,the damage of the pressure sensor of the upper chamber of the hydraulic cylinder,and the fault of the "bursting" of the hydraulic cylinder.In the process of pressing the hot forming hydraulic press,under the condition of increasing deformation resistance of the pressed workpiece,a compound pressure-flow electrical feedback control pump with adjustable power was introduced.The closed-loop speed control of the hydraulic cylinder was realized by PID feedback adjustment of the variable pump power,so that the working speed of the hydraulic press was kept constant.When the pump supply capacity is insufficient,an accumulator supply strategy based on maximum pump power is adopted to maintain the cylinder speed.AMESim software was used to model and simulate the hydraulic system components and control system of hot pressing forming machine,and the influence of energy consumption of hydraulic system,working mode of hydraulic cylinder,working speed and different load forces on the proportion of active work in hydraulic system was studied.Put forward a kind of variable pump power regulation with accumulator for liquid phase speed control strategy,through the established model of thermoforming machine hydraulic system,hydraulic press for hot pressing forming under the different work mode and work into the speed of hydraulic cylinder speed curve was analyzed,and the results show that this kind of hydraulic cylinder speed control strategy when applied to the hydraulic extrusion forming effect is good. |
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