Investigation on dynamic characteristics of herringbone planetarygear system considering tooth surface friction

The sliding friction on the tooth surface is an important factor affecting the dynamic characteristics of herringbone planetary gear system (HPGS) which is a complex high power density system. A novel coupling dynamic model of HPGS with friction effect is proposed through an iterative numerical scheme under the tribo-dynamic condition, and the dynamic characteristics are discussed considering tooth surface friction. The results show that the dynamic meshing force amplitude increases obviously after considering friction, and rises slowly with the increase of roughness. When the load increases gradually, the main peak of dynamic meshing force response increases obviously, but the frequency of the main resonance peak remains unchanged. With the increase of input torque, the main peak of meshing force increases because the input torque, as the input of the transmission system, is positively correlated with the dynamic characteristics of herringbone planetary gear transmission system. The influence of friction excitation on dynamic characteristics gradually decreases with the increase of input speed. As the internal excitation of the system, the friction excitation will also affect the dynamic characteristics. The main peak of dynamic mesh force increases significantly compared with that without considering friction, and increases slowly with the increase of roughness. With the increase of roughness, the dynamic characteristics of the transmission system increase slightly after friction excitation, so the amplitude of dynamic meshing force increases. However, as the roughness continues to increase, the lubrication state changes from full film lubrication to partial elastohydrodynamic lubrication. When the Savg\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${S}_{avg}$$\end{document} of the tooth surface exceeds 1.2 μm, that is, the rough peak contacts, the friction excitation has little effect on the dynamic characteristics, so the amplitude of the main peak of dynamic meshing remains almost unchanged.