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Tribological behavior of coated spur gear pairs with tooth surface roughness

  • Huaiju Liu
  • Heli Liu
  • Caichao Zhu
  • Peitang Wei
  • Jinyuan Tang
Open Access
Research Article


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.


coating gear elastohydrodynamic lubrication (EHL) surface roughness 



This project is supported by the National Natural Science Foundation of China (Nos. 51775060, 51535012, and 51575061).


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© The author(s) 2017

Open Access The articles published in this journal are distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  • Huaiju Liu
    • 1
  • Heli Liu
    • 1
  • Caichao Zhu
    • 1
  • Peitang Wei
    • 1
  • Jinyuan Tang
    • 2
  1. 1.State Key Laboratory of Mechanical TransmissionsChongqing UniversityChongqingChina
  2. 2.State Key Laboratory of High Performance Complex ManufacturingCentral South UniversityChangshaChina

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