强冲击载荷作用下柴油机连杆大头瓦磨损机理研究

Research on wear mechanism of diesel engine connecting rod bearing under strong impact load

针对强冲击载荷作用下柴油机连杆大头瓦磨损机理开展研究,基于微观弹性流体润滑与多体动力学理论,构建了柴油机曲柄连杆机构多体动力学模型,对连杆大头瓦进行润滑仿真研究,获得轴瓦瞬态润滑特性,掌握油膜压力、粗糙接触压力以及油膜厚度变化规律。在此基础上,研究不同轴瓦间隙、工作负荷及转速条件对大头瓦润滑特性的影响,分析油膜力、粗糙接触力以及峰值油膜压力的变化规律;进一步,建立磨损模型分析强冲击载荷作用下大头瓦磨损深度。理论方程结果通过故障模拟实验进行了验证,可为连杆大头瓦磨损故障机理与故障诊断研究提供指导。

Based on the theory of micro-elastic fluid lubrication and multi-body dynamics,a multi-body dynamic model of diesel engine crank-connecting rod mechanism is built to study the wear mechanism of diesel engine connecting rod big end bearing under strong impact load.The lubrication simulation study of connecting rod big end bearing is carried out to obtain the transient lubrication characteristics of bearing pad and master the change law of oil film pressure,rough contact pressure,and oil film thickness.On this basis,the influence of different bearing clearance,working load and rotating speed on the lubrication characteristics of the big end bearing is studied,and the variation rules of oil film force,rough contact force and peak oil film pressure are analyzed.Furthermore,the wear model is established to analyze the wear depth of the big head pad under strong impact load.The results of the theoretical equation are verified by the fault simulation test,which provides guidance for the research on the wear fault mechanism and fault diagnosis of the connecting rod big end bearing.