Abstract:Aimed at the tribologic design problem of a large fanshaped bearing with PTFEmetal composite thrust pads used in hydro power unit,a three dimensional thermohydromechanical coupled elastohydrodynamic lubrication model of the composite pad was established.The effects of the dimension of pad structure on the bearing performances were analyzed.The results show that the thickness of PTFE has a large impact on the bearing performances,too thick of PTFE layer will have adverse effect to contact strength of pad surface,elastohydrodynamic lubrication state and heat dissipation of the bearings,in especial,the contact temperature is raised rapidly along with increasing of PTFE thickness.The increasing of thicker steel base can increase the minimum thickness of oil film at a certain extend,but has little effect on maximum contact temperature and contact strength of surface of pad.