考虑空穴和微观弹流润滑效应的连杆大头轴承热弹流混合润滑分析

基于多体动力学原理建立了考虑空穴效应和微观弹流润滑效应的连杆大头轴承热弹性流体动力混合润滑的计算模型,提出了穴蚀位置的识别方法,分析了轴承润滑状态并获得了轴承摩擦损失的热量分配方法.结果表明:连杆大头轴承处于混合润滑状态,其粗糙接触发生在上轴瓦顶部的两侧边缘;结合轴心轨迹、润滑油填充率、润滑油填充率的变化率和液动油膜压力变化率可以有效识别穴蚀位置;连杆大头轴承的平均摩擦功率为0.44kW,最大粗糙摩擦功率仅为111.1mW,但对其瞬时摩擦功率的监测并不能判断局部的润滑状态;大头轴承的润滑热量散失以热传导为主要方式.

Mixed Thermo-Elastohydrodynamic Lubrication of Connecting Rod Big End Bearing Considering Cavitation and Micro-Elastohydrodynamic Conditions

Abstract： Based on multi-body dynamics, the lubrication calculation model was built for connecting rod big end bearing with consideration of mixed thermo elastohydrodynamic, cavitation and micro-elastohydrodynamic conditions. The method to find cavitation erosion region was proposed, the lubrication state was analyzed, and the heat dissipation of frictional power loss was calculated. The results show that the bearing is in a mixed lubrication state, the asperity contact takes place at both edges of upper bearing top; the cavitation erosion position is recognized by the axis orbit, the lube oil fill ratio, the fill ratio rate of change and the hydrodynamic pressure rate of change; the mean frictional power is 0.44 kW; the maximum transient asperity frictional power is only 111.1 mW, and the monitoring of transient frictional power will not accurately recognize the local lubrication state; and the heat conduction is the main way of energy dissipation in big end bearing lubrication.
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