A time‐varying meshing stiffness model for gears with mixed elastohydrodynamic lubrication based on load‐sharing

Abstract

In mixed elastohydrodynamic lubrication (EHL), the load distribution between the gear meshing surfaces is shared by the oil film and the asperities of the gear's rough surface. Based on the load‐sharing concept, this paper proposes a time‐varying meshing stiffness (TVMS) model for gears with mixed EHL. The initial step involves the utilization of the Greenwood‐Williamson model to calculate the contact stiffness of surface asperities, while the lubricating film is assessed using a curve‐fitting formula to investigate the influence of gear surface morphology on TVMS. Subsequently, the incorporation of gear fillet foundation deformation and friction enables accurate TVMS determination. The proposed method is employed to examine the meshing stiffness of the gear pair under both dry lubrication and EHL conditions. Comparative analysis reveals favorable agreement between the proposed model and experimental results obtained under dry lubrication, thereby highlighting the superior performance of the proposed approach. Moreover, the time‐varying friction coefficient under EHL is computed, and the impacts of gear surface morphology parameters, temperature, speed, and load on lubrication conditions and TVMS are investigated. The findings presented in this paper contribute significantly to advancements in gear design and performance.

Dynamic analysis of planetary gear transmission based on Lagrange interpolation polynomials

“…In EHL conditions, the load distribution between the gear meshing surfaces is shared by the oil film and the asperities of the gear's rough surface. To improve the modeling accuracy, the time-varying meshing stiffness (TVMS) of the gear pairs under EHL is calculated based on load-sharing concept in the previous research [23]. The TVMS calculation model considers that contact load between the meshing surfaces of the gear pair is distributed among the asperities and the lubricating film under mixed EHL, and the TVMS is calculated using the potential energy method.…”

“…The contact stiffness and time-varying friction coefficient of the gear pair are determined through load-sharing analysis. The TVMS calculation is found in [23]. in details.…”

“…h is the oil film thickness. The oil film pressure and thickness are calculated by the equations ( 7) and (33) in [23].…”

“…The meshing damping ratio of gears ς = 0.10 [28] is taken in simulation. Usually, the coefficient of friction is small under mixed EHL conditions, and it is set as 0.05 [23]. The tooth backlash is 0.5 µm [18].…”

“…To investigate the influence of temperature, the speed of the gear is set to 1000 rpm, the load of the carrier is 50 N•m, and the viscosity of the lubricating oil at different temperatures is calculated by the equation (44) in [23]. The other parameters are set as previously.…”