Abstract: The crankshaft main bearing of a four-cylinder marine power generation diesel engine has been examined based on the multi-body dynamics theory, thermos-elasto-hydrodynamic lubrication mechanism and asperity contact theory, aiming at the reduction of the vibration of the marine diesel engine and the optimization of the lubrication characteristics of the crankshaft main bearing. The lubrication model of the bearing system is established for coupling analysis of dynamics and tribology, obtaining the vibration and lubrication of the five main bearings of the diesel engine crankshaft. It is found that the 2nd, 4th and 5th main bearings of the diesel engine all have the characteristics of boundary lubrication. The influence of multiple bearing parameters on the lubrication characteristics of the main bearings are studied by using the finite element simulation analysis based on the orthogonal test. It concludes that the bearing clearance and oil supply temperature greatly affect the lubrication of the main bearing, followed by the surface roughness of the bearing pad and the oil supply pressure, while the width of the bearing pad is the smallest. The design of the crankshaft-bearing parameters of the original diesel engine is optimized to propose an improved scheme, resulting in a 48.9% increase in the extreme value of the minimum oil film thickness, a 53.2% increase of the minimum oil film thickness and a 21.5% reduction of the asperity contact peak pressure. The lubrication characteristics of the diesel engine are finally improved.

Key words: main bearing, orthogonal test, thermoelastic fluid dynamic pressure lubrication theory, analysis of variation

摘要： 为减少船舶柴油机振动,优化主轴承润滑性能,该文基于多体动力学理论、热弹性流体动压润滑理论和微凸体接触理论,以某四缸船用发电柴油机曲轴和主轴承为研究对象,建立轴承系统润滑模型,综合进行动力学和摩擦学的耦合分析,得出柴油机曲轴5道主轴承的振动和润滑结果,研究发现柴油机第2、4、5道主轴承都存在边界润滑的特征。基于正交试验,采用有限元模型仿真分析,研究多种轴承参数对主轴承润滑性能的影响规律,得出轴承间隙和供油温度对主轴承润滑影响最大,轴瓦表面粗糙度和供油压力次之,轴瓦宽度最小的结论。对原有柴油机曲轴和轴承参数进行优化设计,提出改进方案,使得最小油膜厚度（极值）提高48.9%,最小油膜厚度（平均值）提高53.2%,微凸体接触峰值压力减少21.5%,柴油机润滑性能得到提升。

关键词: 主轴承, 正交试验, 热弹性流体动压润滑理论, 方差分析