Negative Pressure in the Oil Film of Journal Bearing : 1st Report : Modelling of Negative Pressure Development and Influences of Parameters on Pressure Distribution

Abstract

Using a bubble theory which takes into account the surface dilatational viscosity κ, influences of eccentricity ε, 4 bubble and 4 bearing parameters on pressure distribution are studied for the oil film in journal bearing : When κ is neglected, the maximum negative pressure is given by a formula containing only a dimensionless surface tension. For small ε, pressure distribution scarcely depends on bubble parameters, and coincides nearly with that calculated by conventional theory under Reynolds condition. For large ε, it changes also with bubble parament values. Whether ε is small or large, the maximum pressure hardly depends on bubble parameters, but depends only on bearing parameters. It is nearly equal to that calculated by conventional theory under Reynolds condition. For increasing ε, κ and shaft speed, the pressure distribution tends to that of Sommerfeld type.