Design And Simulation Of Planetary Gear CVT For Electric Vehicle

With the increasing shortage of energy and environmental pollution,reforming the traditional internal combustion engine,finding new alternative energy sources and researching and developing low-emission and energy-saving automobiles have become the common goal of many countries.Pure electric drive is the main strategic orientation for the development of new energy automobiles and the transformation of automobile industry.As one of the core components of automobile,transmission has also received extensive attention.Based on the existing planetary gear transmission,this paper presents a new type of planetary gear CVT with internal meshing of two motors,which can directly achieve deceleration and increase speed by adjusting the speed of input and output of two motors without changing the transmission ratio.In-depth study of the transmission output and efficiency changes when the output of two motors changes,and build a simplified vehicle model simulation to verify whether the transmission meets the dynamic requirements of the vehicle.According to the design requirements,this paper completes the design of power transmission unit of planetary gear train of CVT,such as planetary gear and solar gear,and the design of speed regulation transmission unit of speed regulation gear,and checks its key parts and dangerous sections.The accurate three-dimensional model of transmission is built by Creo,and the gear pair is assembled according to the connection and transmission relationship.The interference of transmission part is checked.After ensuring that the model is non-interference and the assembly is complete and correct,the output speed of transmission is analyzed by ADAMS,and compared with the theoretical speed,the design is reasonable.According to the interface between ADAMS and MATLAB/SIMULINK software,the model is imported into SIMULINK,and the transmission efficiency is simulated and analyzed according to the mathematical formula.Combining with the analysis results,the output speed range of the speed-regulating motor and the corresponding relationship between the output speed of the two motors and the transmission efficiency are determined when the transmission efficiency is better.Selecting the parameters of an electric vehicle,the whole vehicle is modeled based on SIMLINK software combined with control strategy.According to the different throttle opening input,the detailed simulation analysis is carried out to analyze the dynamic characteristics of the transmission under different working conditions.The research results show that the transmission is more efficient than the single input transmission.Combining with the actual vehicle type analysis,it proves that the transmission meets the dynamic requirements of electric vehicles,and is feasible and can be applied to vehicles.As the electric vehicle industry in China is still in the developing stage,the study of transmission power characteristics has certain guiding significance for the development of electric vehicles.