Abstract
High-pressure viscosity of lubricant is important for elucidating the lubrication state of metalworking, bearing and gear in the elastohydrodynamic lubrication (EHL) region. The van der Waals type viscosity equation was derived in a previous report and it was applied to the estimation of high-pressure viscosity. Furthermore, I accumulated the data of various lubricants for three material-specific constants included in this equation, namely absolute zero viscosity µt=0 [mPa･s], viscosity coefficient S [GPa/K²], and pressure constant PV [GPa]. In this study, a multiple regression equation was derived by conducting the multiple regression analysis on the three material-specific constants as target variables, while the physical properties and the chemical structure of the lubricant were explanatory variables. As a result, it was revealed that the three material-specific constants (ηt=0 mr-eq, S mr-eq, PV mr-eq) in the van der Waals type viscosity equation and the high-pressure viscosity ηmr-eq [mPa･s] could be estimated from this multiple regression equation for unknown lubricants only by analyzing their physical properties and chemical structures, without experimentally measuring viscosity using high-pressure viscosity test apparatus.
