| With the improvement of science and technology level and production processes,the performance requirements for CNC plate shearing machine are increasing.CNC plate shearing machine is mainly composed of mechanical structure,hydraulic system and electronic control system,and among them,the hydraulic system is an very important part,Its design level and reliability directly affect the quality of sheet shearing.High-power plate shearing machine is forging equipment which has high energy consumption.How to develop an efficient and energy-saving hydraulic system which doesn't affect the performance of plate shearing machine is one of the major research projects science researchers currently face.The main research work are as follows:(1)Designed a set of energy-saving hydraulic systems based on the working characteristics of CNC plate shearing machine.The energy consumption of the hydraulic system was analyzed,and the reasons of the energy loss of the system was found out and by extension,the relevant energy-saving measures were put forward that the method of load sensitive pump,accumulator auxiliary tool return and integrated hydraulic system.(2)According to the principle of load-sensitive and pressure-compensated hydraulic system,the mathematical model of load-sensitive pump was established and the influence of load-sensitive valve on the dynamic response of variable pump was analyzed.In order to ensure that the shearing speed control of the cylinder will not be affected by the change of the working load,the speed control circuit was designed which comprises proportional throttle valve and pressure compensating valve,so as to realize the control strategy that the speed of the cutting cylinder has nothing to do with the change of the load.Through comparing the calculation of the efficiency of the quantitative pump system and the load-sensitive system,it was concluded that the load-sensitive system was 13% less energy consumption than the quantitative pump system.Through analyzing the working efficiency by contrast when it has auxiliary accumulator return or not,the result showed when accumulator was adopted,the energy-saving had increased by 4.2% with respect to the lack of accumulator.(3)Through AMESim simulation,the dynamic characteristics of the load-sensitive pump as well as the characteristics of pressure difference and flow of the throttle valve was analyzed by contrast before and after the compensating valve was added.The AMESim simulation model of the hydraulic system of CNC plate shearing machine was established so that the research on the synchronization of the main and auxiliary shearing cylinders,and the pressure and flow characteristics of the variable pump,and the auxiliary return characteristics of the accumulator was conducted.The feasibility of the hydraulic system design of CNC shears was verified by the simulation results.It is of great significance for the future design and application of plate shearing machine in the actual production.(4)Based on the principle of scale experiment,the three-dimensional integrated design of CNC plate shearing machine hydraulic system was carried out and the experimental prototype has been produced.The dynamic characteristics of the hydraulic system was studied experimentally.The effects of different load pressure p,different flow rate Q and structural parameters of the cartridge inserted electromagnetic overflow valve on dynamic characteristics of the hydraulic system are analyzed.The experimental results are in good agreement with the simulation curves,and the correctness of the simulation is verified. |
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