S114011 Analysis of the friction characteristics of oil impregnated sintered bearing and the fluidity of lubricating oil in below freezing conditions : Relationship between the permeability of the bearing and oil film condition in bearing clearance

Abstract

There have been a number of issues concerning the sliding characteristics of oil-impregnated sintered bearings caused at the temperature below freezing. However, the relationship between bearing design parameters and tribological characteristics below freezing has not been clarified yet. In this study, we experimentally investigated the coefficient of friction and separation degree between the oil-impregnated sintered bearing and the journal operating at below-freezing temperature. The experimental results show that unlike the case in the range of a higher temperature than the room temperature, the temperature below freezing conditions yields a higher coefficient of friction μ and a lower separation degree τ at start of operation than those under steady-state condition. The differences in μ and τ between those at start of operation and under steady-state condition are more marked for a higher permeability of the porous matrix.