The Characteristics Research Of Unloading Valve In Loader Hydraulic System Of Double Pumps Confluence

Loader is one of the major models in the construction machinery industry, the broaduse and amounts of output means huge energy consumption, based on the fundamentalconsiderations of environmental protection and economic sustainable developmentstrategy, but also in response to the call of energy conservation and environmentalprotection. currently, loaders design take the energy conservation, high efficiency as itsdevelopment direction, most of the loader with dual-pump, flow-converging steeringpriority hydraulic system has the advantage of energy-saving, one of the key elements ofthis system is unloading valve, unloading valve is the control unit which makes theworking hydraulic system in the high flow low pressure or high pressure low flowfunction mode, so the study of the characteristics of the unloading valve is full ofpractical significance.This paper analyzed the current research in the domestic and abroad and practicalsignificance about the unloading valve which in the loader with dual-pump,flow-converging steering priority hydraulic system, analyzed its structure and workingprinciple, used the knowledge of fluid dynamics and mechanics combined the basicprinciples of the force balance and flow constant to establish its dynamic mathematicalmodel, and the key size parameters of the confluence unloading valve was calculated.The paper used simulation software AMESim code to establish the unloading valvemodel and hydraulic system simulation model, the pressure curves and the flow curves ofthe unloading valve port EF and PW are achieved through the simulation, and analyzeddynamic characteristics influenced by the different parameters of the main valve and thepilot valve, the simulation results provide a reference for the design of structuralparameters of this unloading valve.Use CFD numerical methods, we can observe the flow state runner inside inner flowfield according to the results of the simulation. Firstly, use the three-dimensionalmodeling software Creo to build the three-dimensional inner flow field model of theunloading valve based on its geometric parameter, secondly, use the software ANSYSICEM CFD to mesh the flow field and set boundary conditions, and then use FLUENT tosimulate and obtain the pressure distribution, flow velocity vector diagram, and analyzedthe main valve inlet pressure and velocity influenced by the different opening degrees andthe different structural parameters of the main valve, the results provide a reference for the optimal design flow of flow field.In order to verify the simulation results, the unloading valve system bench testresults compared with the simulation results and the test results, the two curves arebasically the same, it indicates the correctness and reliability of the simulation model, andalso verify the unloading test dynamic characteristics of the valve with a stable, thecheck valve pressure loss and unloading pressure loss are less, it meets the designrequirements. The conclusion provide some reference to its structural design optimizationand improve its working performance, meanwhile has certain practical significance forthe loader with dual-pump, flow-converging hydraulic system ensure efficient productionloader hydraulic system stable and reliable and energy conservation in constructionmachinery.