Effect of roughness on meshing power loss of planetary gear set considering elasto-hydrodynamic lubrication

Abstract

Meshing power loss is one of the most important parts in power loss calculation of planetary gear set. However, most of the conventional methods assumed the friction coefficient between gears as a constant value in the meshing power loss calculation, and most importantly, the influence of gear tooth surface geometry is usually ignored, for example, roughness. Therefore, a new meshing power loss calculation model for planetary gear set that considers tooth surface roughness is proposed on the basis of elasto-hydrodynamic lubrication method. With the proposed model, a planetary gear set dynamic model that considers friction force between gears is first established to study the time-varying meshing forces, sliding speeds, and curvature radii of the gear pairs. Then, an elasto-hydrodynamic lubrication model of the gear pair contact interface is constructed to investigate and modify the friction force distribution in the gear meshing process of the dynamic model iteratively until the meshing forces converge to stable values. Furthermore, the relationship between the tooth surface roughness and film thickness is studied in the elasto-hydrodynamic lubrication model. After that, the meshing power loss is calculated based on the obtained meshing forces, friction coefficients, sliding speeds, and so on. The results show that there is a sudden growth of the meshing power loss at the end of the meshing cycle, which has a good agreement with the meshing force impact. And, it is found that tooth surface roughness has a direct influence on the meshing power loss of sun–planet gear pair, which yields an increasing tendency as the surface roughness growing.

Time-Varying Meshing Stiffness and Dynamic Parameter Model of Spiral Bevel Gears with Different Surface Roughness

“…They investigated the dynamic characteristics of the gear system under different roughness and input torque conditions. Wang et al [6] proposed a new calculation model for meshing power loss in planetary gearsets, considering gear surface roughness based on the elastohydrodynamic lubrication method.…”

Experimental‐based study of gear vibration characteristics incorporating the fractal topography of tooth surface

“…Kim and Singh 11 proposed a noise source model for gear surface roughness considering sliding contact between meshing teeth and verified that the noise level increases with the increase of speed and surface roughness. Wang et al 12 proposed a new model for calculating the power loss of planetary gear meshing considering tooth surface roughness and investigated the relationship between tooth surface roughness and the dynamic response. Zhou et al 13 developed a finite element model of a megawatt wind turbine gear and used the developed model to comparatively study the effects of microstructure, inclusions, and surface roughness on the contact fatigue behavior of the gear.…”

TEHL analysis of VH-CATT cylindrical gear transmission in elliptical contact considering time-varying parameters

“…14 For planetary gear, the model of EHL was established, which consider the effects of roughness. 15 After Pu et al 16 established the EHL model considering roughness of a spiral bevel gear, Zhang et al 17 predicted the coefficient of friction and tooth surface wear of this gear using TEHL technology. After establishing a TEHL model covering the full film, mixed, and boundary lubrication, Simon presented the methods to improve the lubrication performance of hypoid gear based on multi-objective optimization, 18 optimization of manufacture parameters, 19 and machine tool setting parameters.…”