大型推力轴承PTFE-金属复合瓦热弹流润滑设计

Design of PTFE-Metal Composite Pad of Large Thrust Bearing Based on Thermal Hydrodynamic Lubrication Analysis

针对水力发电机组用大型扇形PTFE-金属复合瓦推力轴承摩擦学设计问题,建立复合轴瓦三维热流固耦合的弹流润滑模型,分析轴瓦结构尺寸对轴承性能参数的影响规律。结果表明,PTFE层厚度对轴承性能有非常重大的影响,过厚的PTFE材料对轴承的散热、弹流润滑状态、瓦面接触强度等都会造成不利影响,尤其是会造成轴承接触温度随PTFE厚度增加而迅速升高;钢基体厚度增加够一定程度上增加最小油膜厚度,但对瓦面接触强度和最大接触温度的影响不大。

Aimed at the tribologic design problem of a large fan-shaped bearing with PTFE-metal composite thrust pads used in hydro power unit, a three dimensional thermo-hydro-mechanical 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.