| Nowadays,electric vehicles are becoming increasingly popular due to the shortage of oil energy and the deterioration of environment.However,most electric vehicles are equipped with single speed reducer which cannot meet the requirements of both power and economy.Hence,it is essential to assemble a suitable transmission for an electric vehicle.Taking into account the cost of electric vehicles and the complexity of the transmission system,2-speed AMT has more advantages over other multi-speed transmission.In this paper,a kind of shift mechanism of e-2AMT in a pure electric vehicle has been researched.The shift mechanism is driven by brushless DC motor and composed of a worm gear mechanism,a cam hub and a shift fork.A multi-objective genetic algorithm is used to match the worm gear mechanism ratio and the helical angle of the cam hub in the shift actuator taking the less shift time and lower shift motor power as the optimization target so as to obtain the better mechanism design scheme.After that,the synchronizer and the shift actuator are modeled and analyzed by ADAMS multi-body dynamic analysis software.According to the simulation results,the synchronization process of synchronizer and the overall performance of shift mechanism are analyzed.The shift actuator is modeled by MATLAB / Simulink.Through the joint simulation of MATLAB and ADAMS,the dynamic response and control effect of the shift system are simulated,the performance of the shift mechanism is evaluated according to the selected shift performance indices,and some optimization program of relevant parameters is proposed to enhance the shift quality.Finally,the bench test was carried out to verify the design of the e-2AMT system.The experimental results show that the shift actuator designed in this paper has high reliability,which can meet the accuracy,rapidity and smoothness of the shift process. |
