Elastic Connecting-Rod Bearing With Piezoviscous Lubricant: Analysis of the Steady-State Characteristics

Abstract

The effect of the deformation of an automotive connecting-rod on the oil film characteristics are studied. The simultaneous elastic deformation and pressure distribution are obtained by iterative methods in steady-state conditions under realistic speeds and loads (5500 rpm, 25,000 N). Plane elasticity relations are used in this study. The following parameters are investigated: —bearing characteristics: bearing thickness B and bearing clearance C, —operating conditions: journal speed N and applied load W, —lubricant: viscosity μ0 and piezoviscous coefficient α. As a result of the deformation, the maximum pressure and the attitude angle are decreased and the relative eccentricity is greatly increased. The minimum oil film thickness is slightly but systematically decreased. The piezoviscosity effect is noticeable only at high loads: it increases slightly the oil film thickness and the maximum pressure. An empirical dimensional equation for the minimum oil film thickness hm is derived numerically for the bearing considered. Thus: hm∼μ0NW0.5(1+0.06108α)B0.12C0.09