AT Load Spectrum Establishment Based On Road Test And Numerical Simulation

The large-horsepower hydromel chanical transmission consisting of hydraulic torque converters,planetary gear trains,hydraulic retarders,and electronically controlled hydraulic control systems is a sophisticated device combining electromechanical and hydraulic control.It has an important influence on the dynamic performance of the vehicle.The transmission load spectrum is an indispensable data for transmission design,analysis,and testing.From the perspective of domestic research,the dynamic load spectrum acquisition of automatic transmission basically stays at the theoretical level,and there are few methods and techniques for researching deeply on it.Based on the cooperation project between North University of China and a company in Chongqing about the study of "XXXXX",the numerical simulation of the load signal of the transmission and the study of load spectrum preparation method are carried out.Firstly,a random road model was established in this paper: The power spectrum density data of the road irregularity power spectrum density was discretized to obtain the power spectrum density data.The above data was calculated to obtain the discrete Fourier transform data,and the road roughness data was calculated by the inverse Fourier transform after the data was complemented;Then,the simulation model of the load spectrum of the transmission was established: the two-degree-of-freedom vibration model of armored vehicles and the calculation of the load torque of the automatic transmission were established,the dynamic load moments of different surface transmissions are taken as the torque imposed on the output of the model during simulation.The torque converter model and the engine excitation torque model were established,and the engine excitation torque obtained was used as the torque applied to the input of the model during simulation.The dynamic models of constant speed and acceleration conditions under different gears were established respectively,and the load data were obtained through simulation analysis.Finally,the load spectrum of the transmission was compiled: The data obtained from the simulation was counted by rainflow counting method in order to get the amplitude-average rainflow matrix under different conditions;Then the probability distribution of the average amplitude was tested,and the correlation test shows that the two are independent;Then,the multi-state synthesis,the determination of the maximum amplitude of the average amplitude,and the compilation of the 2D design spectrum were carried out so as to establish the c of the 8-level automatic transmission.Through the research,it could provide a reliable reference for the simulation analysis and establishment methods of the automatic transmission load spectrum in the future.