The helical gear transmission system of hybrid electric vehicle is composed of compound planetary gear mechanism and parallel shaft gear mechanism. Firstly, the structure and working principle of the power transmission system are analyzed and described, and the influence of the vibration of the helical gear transmission system on the power system is analyzed. The dynamic model of helical gear transmission system is established, and the nonlinear dynamic characteristics of the system are deeply studied and analyzed. The specific research work and conclusions are as follows:
(1) The nonlinear dynamic model of the helical gear transmission system of hybrid electric vehicle is established. The nonlinear factors such as time-varying meshing stiffness, tooth side clearance and comprehensive meshing error in the helical gear transmission system are fully considered. Based on the dynamic theory, the relative meshing displacement of each pair of helical gear pairs in the composite planetary row mechanism is deduced, and on this basis, the transverse torsional nonlinear dynamic model is established, Then, the bending torsion axis nonlinear dynamic model of the parallel shaft gear part is established, and the connecting part of the composite planetary gear mechanism and the parallel shaft gear is properly simplified to establish the nonlinear dynamic equation of the whole system. The nonlinear factors of the system are described mathematically, which lays a theoretical foundation for the next research.
(2) Establishment of hybrid electric vehicle power transmission system model based on simulationx software. For the hybrid electric vehicle power transmission system model studied in this paper, it is composed of engine, motor, brake, composite planetary gear mechanism, parallel shaft gear mechanism, etc. 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 mechanism module not in the software, the secondary development is carried out by using Modelica language to generate the required parallel shaft gear module. Finally, the physical model of helical gear transmission system of hybrid electric vehicle is established.
(3) The dynamic characteristic analysis of helical gear transmission system based on simulationx solves the natural frequency of the system with the help of simulationx software, studies the dynamic characteristics of helical gear transmission system, obtains the influence of helical gear parameters such as time-varying meshing stiffness, phase angle, tooth side clearance, meshing damping and bearing support stiffness on the dynamic characteristics of the system, and improves the vibration characteristics of the whole helical gear transmission system through various adjustments. Using the inherent frequency and natural vibration mode analysis module in simulationx software, the helical gear parameters affecting a large natural frequency of helical gear are changed, so that the natural frequency of the system can effectively avoid the meshing frequency within the working speed range of hybrid electric vehicle, so as to improve the vibration characteristics of helical gear transmission system. However, it is also found that the modification of model parameters usually leads to the improvement of only one frequency range. Overall improvement is impossible. In order to obtain a relatively stable transmission system, the system should be adjusted and analyzed in many aspects according to the actual situation, combined with economy and feasibility. In addition, the establishment of virtual prototype of helical gear transmission system provides an intuitive and reliable platform for studying the dynamic characteristics of helical gear transmission system of hybrid electric vehicle.