| As an important construction machinery in the construction industry,concrete pump truck is widely used in modern urban infrastructure.In recent years,in order to meet the demand of high-rise buildings,closed hydraulic system concrete pump truck has become the mainstream of the market.In the actual product,the hydraulic system of pumping unit of concrete pump truck is still deficient,which affects the performance of the product.For example,the pressure shock of the distribution circuit and the heat dissipation performance of the pump return circuit need to be further improved.However,in the process of actual product development,a lot of test and testing work is usually needed to improve the system performance,which inevitably increases the cost of research and development,and many test data are difficult to obtain due to the limitations of test conditions.In view of the above problems,the use of computer simulation software to simulate the hydraulic system of concrete pump truck,the actual product development and performance optimization has great engineering practical significance.Firstly,the flow loss Data of the hydraulic pump under different speed,pressure difference and swash plate swing range were obtained by means of test and test,and imported into the simulation model in the form of data data file.The flow loss of the hydraulic pump during simulation was simulated.The key components in the subsystem of the hydraulic system of the pumping unit are modeled respectively.The A10 VO constant pressure variable pump and A4 VG bidirectional variable pump are analyzed according to the variable principle and technical parameters.The simulation model is built by using the signal library,mechanical library and hydraulic library in AMESim.The simulation model of constant pressure variable pump and bidirectional variable pump is verified by comparing the sample curves.According to the sample information and design drawings of the actual product,its internal structure is analyzed and its key parameters are measured.The distribution cylinder,pumping main cylinder and flushing valve are modeled by using the HCD library in AMESim.Based on the analysis of the working principle of the electronic control system of the closed system concrete pump truck,the electronic control constant power and reversing logic models are established by using the state logic library and signal library,and combined with the pipeline layout of the hydraulic system,the whole simulation model of the hydraulic system of the pumping unit is completed.Secondly,the pump unit hydraulic system test bed is built.The test data of 7 measuring points of concrete pump truck with closed hydraulic system were collected and compared with the simulation results of air pump,which verified the accuracy of the simulation model.The results show that the simulation model of the hydraulic system of the closed pumping unit can correctly simulate the pressure change process of the hydraulic system under normal conditions,and the relative error of the simulation model in the stable pumping stage is less than 8%,which lays a foundation for the loading analysis and optimization of the hydraulic system.Finally,the loading model of the hydraulic system of the pumping unit is established,and the dynamic characteristics of the hydraulic system under typical working conditions are simulated and analyzed.The influence factors of pressure shock in distribution loop and pump return flush flow in hydraulic system of pumping unit are discussed.The influence factors of pressure shock in buffer chamber in distribution loop and pump return flush flow in different parameter values are simulated and analyzed.A set of parameter optimization scheme is proposed.By comparing the original scheme,it is found that the optimized scheme reduces the pressure shock of buffer chamber in the distribution loop by about 94 bar,and the system flushing flow increases by about15.4L/min,which verifies the effectiveness and accuracy of the optimized scheme. |
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