Analysis of natural characteristics of double input face gear split-parallel transmission system

The double input face gear split-parallel transmission system was taken as the research object, and the translation-torsion coupling dynamic model including transmission errors, meshing damping and support stiffness was established based on the lumped parameter method. In addition, by analyzing the relative displacement relationship and force situation of each gear pair, the motion differential equations of each gear were established according to Newton's second law. Meanwhile, the natural frequencies and mode shapes of the system were obtained through utilizing the eigenvalue of the dynamic equation, and the influence laws of the meshing stiffness and support stiffness on the natural frequencies were also studied. By solving the modal strain energy and kinetic energy of the system, the frequency order corresponding to the larger modal energy of each gear was revealed. The results show that among the natural frequencies corresponding to the 7 multiple roots, 1 multiple root has the largest number of natural frequency, most of which contains high-order frequencies. The system contains many vibration modes, and there are unique translational vibration modes and torsional vibration modes of each drive stage gear. Similarly, in the vibration mode vector corresponding to the natural frequency with the same number of multiple roots, multiple vibration modes coexist. For the total system modal energy, the total strain energy at the 46th order frequency is the largest, and the system overall deformation is the largest, and the total kinetic energy at the 60th order frequency is the largest, and the system vibration is the most intense. The higher-order natural frequencies are more sensitive to changes in meshing stiffness and support stiffness, and the sensitivity increases sequentially with the increase of stiffness. Meanwhile, the change of the system stiffness will lead to modal transition when the natural frequencies encounter similar frequencies, and the vibration modes will be exchanged suddenly, and then it will remain unchanged until the frequencies are close again. Therefore, The mode transition points should be avoided as far as possible in the dynamic design. © 2022 Central South University of Technology. All rights reserved.