| The gearbox performance directly affects the transmission performance of the car chassis,and the gearbox performance testing is an important means to evaluate the performance index of gearbox.In this paper,the gearbox online test bench uses the hydraulic system to realize the movement in the detection process,therefore,it is a necessary link to maintain the good dynamic performance of the hydraulic system of test bench to ensure the accuracy of test results.Establish a mathematical model of each component of the hydraulic system,and the dynamic mathematical model of the system is simulated by software to analyze and optimize the dynamic performance of the system.This paper is aimed at the online test bench for a certain type of automobile manual gearbox,to design the test bench hydraulic system and analyse the dynamic characteristics of the hydraulic system.Mainly completed the following research content:(1)The composition and working process of the gearbox online test bench were discussed,and the schematic diagram of the hydraulic system of the gearbox online test bench were designed,the composition and working principle of the hydraulic system were analyzed,the calculation and selection of the basic components in the hydraulic system were completed,and the performance of the hydraulic system was checked.(2)The node cavity method was selected as the dynamic modeling method of the hydraulic system in this paper;the mathematical models of hydraulic oil,hydraulic pipe,quantitative hydraulic pump,direct-acting relief valve,three-position four-way reverse valve,one-way throttle valve,accumulator,pressure-reducing valve and hydraulic cylinder were established.(3)The simulation model of each hydraulic component was established by using MATLAB/Simulink,and simulate the model to verify the accuracy of the corresponding component mathematical model;based on the node cavity method,the Simulink simulation model of clutch separation and coupling hydraulic subsystem of the test bench was established,the simulation model established in this paper was compared with the simulation results of the mature AMESim model to verify the accuracy of the established model;through dynamic characteristic analysis,to obtain the influence of parameter change of different components on dynamic characteristic of hydraulic system.(4)The genetic algorithm was used to optimize the structural parameters of one-way throttle valve.Through optimization,to obtain the optimal value of the orifice diameter of the one-way throttle valve of the hydraulic cylinder at the desired stable speed and the dynamic response of hydraulic cylinder speed under the condition of optimal result,the results show that the hydraulic system had good stability and strong anti-interference ability.The accuracy of the simulation results was verified through experiments.Main conclusions and innovations of this paper:(1)Based on the node cavity method and the selection principle of the electromagnetic reversing valve,a mathematical model of electromagnetic reversing valve with oil pressure as input and valve orifice flow as output was established.(2)According to the design of gearbox online test bench hydraulic system,the mathematical model of the hydraulic system of test bench was established based on the nodal cavity method,and the influence of different parameters on the dynamic characteristics of the hydraulic system of the gearbox online test bench was analyzed,it provided a reference for improving the dynamic characteristics of the hydraulic system of the gearbox online test bench.(3)To obtain the simulation parameters of the hydraulic system of the test bench under the condition of setting speed by using genetic algorithm and the dynamic response of the hydraulic system of the test bench when it reaches the setting speed. |
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