Structure Design And Optimization Of Multi-way Valve For Tractor Hydraulic System

Tractor is one of the most primary agricultural machinery in our country,and the hydraulic system as a transmission technology has become an important part of tractor.Moreover,multi-way valve is the most key component in tractor hydraulic system,its main function is to control one or more actuators’ movement,so its performance determines the whole performance of tractor.But at present,the multi-way valve of domestic tractor hydraulic system exists some problems,such as excessive leakage,serious pressure loss and excessive operating force of hands and so on,which seriously restrict the development of multi-way valve as well as agricultural machinery equipment.Aiming at above problems,this paper adopts the multi-way valve of 1002/1202 series caterpillar tractor hydraulic system as a research object,and summarizes the development status of domestic and foreign multi-way valves,and puts forward a particular form of designing scheme of the new-type four-position spool valve notches.The methods of theoretical analysis,numerical simulation and experimental verification are used in combination for further researching.The mathematical model of new-type notches is constructed,particle swarm optimization algorithm is used to optimize the structure of notches and we can get the optimal design parameters.Multiway valve geometry model is built by Solidworks software,then the model will be imported to the fluid simulation software Fluent to finish the simulation calculation based on computational fluid dynamics principle,the results show that the new valve compared with the original valve,flow channel local maximum velocity decreases,pressure loss and leakage also reduces,steady-state flow force acting on the spool decreases in the process of working,furthermore the operating force of hands is less than the maximum steady-state flow force,which enhance the working stability of multi-way valve.According to the industry standard,this paper develops a test scheme and designs principle diagram of test system,using the comprehensive hydraulic testing platform to carry out the relevant performance test of multi-way valve,test results show that the experimental data and simulation data are basically consistent,which verify the correctness of flow simulation and the reasonability of the structure of new-type four-position spool valve notches.The structure of four-position spool valve notches of tractor hydraulic systemmulti-way valve is optimized in this paper,which can improve valve port flow characteristics of multi-way valve and enhance the overall performance of tractor.At the same time,the flow field simulation and test method can be used to guide the design of multi-way valve and other hydraulic components,and provide data support and theoretical guidance for the development of related products.