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The Effect of Surface Roughness to Elastohydrodynamic Lubrication in Spur Gear with non-Newtonian Lubricant

Khanittha Wongseedakaew*

Abstract

This paper presents the effect of surface roughness to performance characteristics of transient isothermal elastohydrodynamic lubrication in line contact of spur gear with non-Newtonian fluids. The time dependent Reynolds equation, elastic equation and viscosity equation were formulated for compressible fluid.

Newton-Raphson method and multigrid method were implemented to obtain the film pressure profiles, film thickness profiles and traction coefficient in the contact region at various loads and speeds. The simulation results show that roughness amplitude has a significant effect on the film pressure in the contact region. The film thickness decrease but traction coefficient increases when surface of gear teeth was rough surface. The film thickness reaches its minimum at approach point when the line of action increase film thickness was increase. The minimum traction coefficient was occurrence at pitch point. The increasing loads, film pressure and traction coefficient increase but film thickness decrease. The film thickness and traction coefficient increase when the speeds increase.

Keywords: Spur gear, Modified Reynolds equation, Multigrid method, non-Newtonian fluid.

*Lecturer, Department of Mechanical Engineering Technology, Collage of Industrial Technology,

King Mongkutts University of Technology North Bangkok, Bangkok 10800, Email: khanitthaw@kmutnb.ac.th

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