Modified Reynolds Equations for High Viscosity Surface Layer and Thin Film Lubrication Analysis of Tapered/Tapered Land Bearings as Models of Surface Texture

Autor: Kyosuke Ono
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Tribology Online, Vol 14, Iss 5, Pp 267-278 (2019)
Druh dokumentu: article
ISSN: 1881-2198
DOI: 10.2474/trol.14.267
Popis: The development of thin film lubrication theory is vital for future micro-textured lubrication technologies. Therefore, a modified Reynolds equation was derived in this research by incorporating the variable viscosity effect in a tribochemical adsorbed layer. The modified factors of the Reynolds equation were expressed as closed form functions for a one-sided viscosity function determined from the measured effective viscosity. Using the one-dimensional modified Reynolds equation, the load capacity and friction coefficients of micro-tapered/tapered land bearings as texture models were numerically investigated. By performing a parametric study with different viscosity ratios (10 and 100), taper lengths (10, 50, and 250 µm), taper angles, and land length ratios and a surface layer thickness of 10-nm, it was found that a high load capacity and an extremely low friction coefficient of less than 10–4 on the stationary surface could be achieved with a bearing gap of a few tens of nanometers. Since the surface height irregularities between the textures can be compensated for by the elastic deformation caused by high pressures, the lubrication regime in a parallel textured slider can be realized if the roughness heights on the mating surfaces are reduced to less than the bearing gap, using the running-in process.
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