The dynamic characteristics of the helical gear transmission system of a new compound power split hybrid electric vehicle of a Chinese company will be studied. When analyzing the dynamic characteristics of the whole system, it is necessary to study not only the nonlinear dynamic characteristics of the compound planetary gear train and the parallel shaft gear, but also the nonlinear dynamic characteristics of the connection between them. The details are as follows:
(1) Firstly, the structure and working principle of the power transmission system of hybrid electric vehicle are described, the vibration and noise generation mechanism of helical gear system in the system is analyzed, and the influence of its vibration on the power transmission system is analyzed.
(2) The helical gear transmission system is divided into two parts: composite planetary gear mechanism and parallel shaft gear mechanism. Fully considering the nonlinear factors such as time-varying meshing stiffness, tooth side clearance and comprehensive meshing error in the helical gear transmission system, the transverse torsional nonlinear dynamic equation of the composite planetary gear system is established by using the second kind of Lagrange equation, and then the bending torsional shaft nonlinear dynamic model of the parallel shaft gear is established, The connecting part is properly simplified, the nonlinear dynamic equation of the whole helical gear system is established, and the nonlinear factors in the system are mathematically described.
(3) The multi-disciplinary advanced modeling and simulation software ITI simulationx is selected as the platform, the corresponding physical modules are established by using the rich physical model library in the software, and the relevant theories of each module are described. Based on the parallel shaft gear module not in the software, the secondary development is carried out with Modelica language to generate the required physical module, and finally build the physical model of hybrid electric vehicle powertrain.
(4) The equations for solving the natural frequency of the system are established, the natural frequency of the power transmission system of hybrid electric vehicle is solved with the help of simulationx software, the dynamic characteristics of helical gear transmission system are studied, and the time-varying meshing stiffness, meshing phase, tooth side clearance, meshing damping and other main parameters as well as the influence of bearing support stiffness on the dynamic characteristics of the system are obtained. Through various adjustments, Improve the dynamic characteristics of the whole helical gear transmission system. Using the natural frequency and natural vibration mode analysis module in simulationx software, the influence degree of parameters and the sensitivity of natural frequency and vibration mode to parameter changes are emphatically considered. By changing relevant parameters, the natural frequency of the system can effectively avoid the meshing frequency within the working speed range of hybrid electric vehicle, so as to avoid resonance. The vibration characteristics of hybrid system are improved. In addition, the virtual prototype of helical gear transmission system in its power transmission system is established by using the multi-body dynamics Library in simulationx, which provides an intuitive and reliable platform for the study of the dynamic characteristics of the whole system.