Dynamic characteristic analysis of multi-stage gearbox transmission system considering gearbox flexibility

ZHAO Yong; YU Ying; ZHANG Yuanyuan; YANG Jiajun; QIN Lijun

doi:10.16578/j.issn.1004.2539.2026.03.010

Abstract：[Objective]In order to accurately calculate the dynamic characteristics of the multi-stage gear transmission of a loader and the influence of gearbox structure flexibility on dynamic response,an efficient numerical calculation method for dynamic response considering the flexibility of the casing was proposed.[Methods]Firstly,considering the stiffness and error excitation of the gear transmission system,a multi-degree-of-freedom dynamic model of the multi-stage gear transmission system with bending-torsion coupling was established using the concentrated mass method.Secondly,using finite element software and Romax software,a finite element model of the gearbox was established.Finally,based on the substructure method,a coupled dynamic equation for the gearbox and transmission system was constructed,which added a new degree of freedom for the gearbox condensation point on the basis of the transmission system dynamic equation.The dynamic meshing force and bearing support reaction could be obtained by using the Runge-Kutta method.[Results]The results show that the influence of gearbox flexibility on the transmission system is related to the position of the gear pair and working conditions.At low speeds and light loads condition,the influence of gearbox flexibility on the dynamic meshing force in the transmission system is relatively small.Due to the direct contact between the bearing and the gearbox,the influence of the gearbox on the transmission system is attenuating from the bearing to the gear pair.Therefore,the influence of the gearbox flexibility on the bearing support reaction is greater than that on the gear meshing force.Therefore,in order to accurately predict the vibration noise of high-speed and heavy-duty complex transmissions,the flexibility of the gearbox can't be ignored.