Analysis of lubrication and dynamic characteristics of spur gear considering angular misalignment error

Angular misalignment error is a common issue in gear transmission systems, significantly altering mesh characteristics and structural integrity. While numerous studies have investigated the contact mechanics and dynamic responses induced by these errors, their coupled influence on transient elastohydrodynamic lubrication (EHL) has been largely overlooked, limiting the predictive accuracy of current models. To address this fundamental gap, this paper proposes a novel integrated multi-physics framework that systematically couples a three-dimensional gear contact model, a line-contact EHL model, and a translational-torsional dynamic model. The primary novelty lies in capturing the underlying interaction mechanisms where misalignment-induced non-uniform load distributions directly alter real-time lubrication performance, which subsequently feeds back into the dynamic system via modified oil film stiffness and damping. By systematically evaluating tilting, twisting, and comprehensive misalignment errors, the results reveal that misalignment severely increases the amplitude of oil film pressure and thickness along the tooth width while reducing the total contact area. Notably, twisting misalignment error exhibits the most pronounced detrimental influence due to its higher sensitivity to mesh clearance. Furthermore, dynamic responses of the gear system demonstrate a significant increasing trend as the error amplitude grows. Finally, experimental validation utilizing a customized misaligned gear test rig confirms the accuracy of the proposed model. This work provides a comprehensive analytical framework for investigating the complex tribo-dynamic characteristics of gear systems under angular misalignment.