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

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 equ...

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Bibliographic Details
Main Author: Kyosuke Ono
Format: Article
Language:English
Published: Japanese Society of Tribologists 2019-12-01
Series:Tribology Online
Subjects:
Online Access:https://www.jstage.jst.go.jp/article/trol/14/5/14_267/_pdf/-char/en
Description
Summary: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.
ISSN:1881-2198