悬链线型线轴瓦对连杆大头轴承润滑特性的影响

Influence of Catenary Profile on Lubrication Characteristics of Conrod Big-end Bearing

针对柴油机连杆大头轴承润滑不良和摩擦磨损的问题,结合轴承型线的设计理论,建立了悬链型线的数学表达式。运用AVL POWER UNIT搭建连杆柔性多体动力学模型,研究了连杆大头轴承的悬链线型线对其润滑特性的影响。结果表明:当连杆大头轴承采用悬链线型线轴瓦时,随着型线径向变化量的逐步增加,峰值油膜压力先减小后增大,最小油膜厚度先增大后减小,总摩擦功耗先减小后增大。当采用径向变化量为方案4(变化量6μm)的悬链线型线轴瓦时,最小油膜厚度增加了0.22μm,峰值油膜压力减少了10.92 MPa,总摩擦功耗减少了0.28 kW,有利于减小轴承的摩擦磨损功耗和改善连杆大头轴承的总体润滑性能。通过曲线拟合分析得到了最小油膜厚度、峰值油膜压力和总摩擦功耗这3个评价参数的函数关系,为连杆大头轴承润滑特性的优化设计提供参考依据。

Because of poor lubrication and friction and wear of the conrodbig-end bearing of a diesel engine, based on the design theory of bearing profile, the mathematical expression of catenary profile is established. Using the AVL power unit that builds a flexible multi-body dynamics model of the conrod, the influence of the catenary profile of the conrod big-end bearing on its lubrication characteristics was analyzed. The calculation results show that: when the radial variation of thecatenary profile gradually increases, the peak oil film pressure first decreases and then increases, the minimum oil film thickness first increases and then decreases, and the total friction power loss first decreases and then increases. When the catenary bushing with the radial variation of option 4(variation 6 μm) is adopted, the minimum oil film thickness increases by 0.22 μm, the peak oil film pressure is reduced by10.92 MPa, and the total frictional power loss is reduced by 0.28 kW, thus being useful toreduce the friction and wear power consumption of the conrod big-end bearing and to improve its overall lubrication performance. Through curve fitting analysis, the function relationship of the three evaluation parameters of minimum oil film thickness, peak oil film pressure and total friction power loss is obtained, providing a reference for the optimal design of lubrication characteristics of the conrod big-end bearing.