Tribological behavior of coated spur gear pairs with tooth surface roughness

Abstract

Abstract:Coating is an effective way to reduce friction and wear and to improve the contact-fatigue lives of gear components, which further guarantees a longer service life and better reliability of industrial machinery. The fact that the influence coefficient linking the tractions and stress components could not be expressed explicitly increases the difficulty of coated solids contact analysis. The complicated tribological behavior between tooth surfaces influenced by lubrication and surface roughness further adds difficulty to the coated gear pair contact problems. A numerical elastohydrodynamic lubricated (EHL) contact model of a coated gear pair is proposed by considering the coupled effects of gear kinematics, coating properties, lubrication, and surface roughness. The frequency response function and the discrete convolute, fast Fourier transformation (DC-FFT) method are combined to calculate the surface deformation and the subsurface stress fields at each meshing position along the line of action (LOA). The Ree-Eyring fluid is assumed to incorporate the non-Newtonian effect, which is represented in the generalized Reynolds equation. Influences of the ratio between the Young's modulus of the coating and the substrate on the contact performance, such as pressure, film thickness, tooth friction coefficient, and subsurface stress field, are studied. The effect of the root mean square (RMS) value of the tooth surface roughness is studied by introducing the roughness data, deterministically measured by an optical profiler.

Study on contact fatigue of a wind turbine gear pair considering surface roughness

“…Due to the increasing demand for improved performance, reduced weight, and increased service lives of advanced geared machines such as wind turbines, which present significant contact fatigue issues leading to economic repercussions, diverse engineering techniques have been applied such as case carburizing [1], nitriding [2], and coating [3] to improve the resistance of gear contact fatigue failure. Gears failure due to rolling contact fatigue (RCF) occur in a variety of modes such as spalling [4], micropitting [5], and tooth flank fracture [6].…”

Roles of microstructure, inclusion, and surface roughness on rolling contact fatigue of a wind turbine gear

“…As the requirements on power densities and load capacities of wind turbine gearboxes keep increasing, the probabilities of gear RCF phenomena increase. Therefore, carburized or nitrided gears are widely used as they have high resistance to fatigue. However, different failure modes due to RCF, such as micropitting, pitting, and deep spalling, still occur frequently during engineering practice.…”

Nonlinear Dynamic Characteristic Analysis of a Coated Gear Transmission System

“…It brings a new research task for developing innovative materials, in which the surface-strengthening technology is a key. Currently, coat plating has been extensively applied in gear components to obtain higher power densities and fatigue lives [1][2][3]. On the other hand, with the increasingly strict restriction on transmission noise, the prediction and control of its vibration have attracted tremendous attention.…”