Introduction: Helical gears are essential components in high-speed transmission systems, in which meshing power loss arising from friction, viscous shear, and thermal effects substantially compromises transmission efficiency and operational reliability. This study develops a simplified, physics-based method to predict the meshing power loss of helical gear pairs. Methods: A novel simplified calculation method is proposed by reducing a conventional two-dimensional finite line-contact elastohydrodynamic lubrication (EHL) model into a one-dimensional formulation through axial slicing. The model integrates EHL theory, numerical iterative computation, and physical mechanisms related to oil-film shear, viscous dissipation, and tooth-surface friction. Gear kinematics, thermal-coupled film properties, instantaneous engaged-tooth number, load distribution, and the pinion helix angle are simultaneously incorporated. Results: The method was applied to the first-stage helical gear set of a high-speed electric vehicle reducer. The results capture the transient meshing power loss associated with both single-tooth pair meshing and multi-tooth pair interactions. The predicted power loss trends align with the physical evolution of contact load and sliding ratios along the mesh. Discussion: Compared with traditional high-dimensional EHL models, the proposed approach significantly reduces computational effort while maintaining sufficient accuracy for engineering applications. Its ability to describe the dynamic characteristics of meshing loss provides valuable insight into the efficiency behavior of the high-speed helical gears cycle. Conclusion: The proposed simplified model offers a practical and efficient tool for predicting meshing power loss in helical gear transmissions, supporting the design and optimization of highefficiency gear systems used in electric vehicle drivetrains and other high-speed applications.
Jia et al. (Fri,) studied this question.