基于热弹性流体动压润滑的柴油机曲轴主轴承润滑特性分析

Characteristic Analysis of Diesel Engine Main Bearing Lubrication Based on Thermo-elastic Hydrodynamic Pressure

基于平均流量模型和Greenwood/Tripp微凸体接触理论,采用有限元法与多体动力学结合的方法,考虑柴油机曲轴主轴承轴颈和轴瓦表面粗糙度、曲轴和轴承座的变形及热效应等影响因素,建立某四缸四冲程柴油机曲轴实体模型和数学模型,分析了曲轴轴承间隙、供油压力和温度、油槽宽度等参数变化时的主轴承润滑特性,并对主轴承进行了优化.最终结果表明,四缸四冲程柴油机第二道和第四道主轴承润滑情况较差,通过增大油槽宽度、减小滑油压力、增大轴承间隙、增加粗糙度等手段可以保证柴油机主轴承最小油膜厚度增加,最大油膜压力减小,实现良好润滑。

Based on the average flow model and the Greenwood/Tripp micro convex body contact theory and taking account of such factors as the main bearing of diesel engine crankshaft journal and bearing surface roughness, deformation of the crankshaft and bearing seat and thermal effect, the paper establishes a four-cylinder four-stroke diesel engine crankshaft physical model and mathematical model by using the combined method of finite element method（fem） and multi-body dynamics. The paper also analyzes the crankshaft bearing clearance, oil pressure and temperature and groove width parameter changes of main bearing lubrication characteristics, and the main bearing was optimized. The final result shows that lubrication condition for the second and the fourth is relatively poor. By means of increasing the groove width, reducing the pressure of lubricating oil, increasing the bearing clearance and roughness, the diesel engine main bearing minimal oil film thickness increases, the maximum oil film pressure decreases, and good lubrication can be finally achieved.