空穴效应对连杆小头轴承润滑及动力学特性的影响

Study on the Influences of Cavitation Effect on Lubrication and Dynamic Characteristics of Connecting Rod Bearing

将热弹流理论与活塞连杆组柔性多体动力学分析结合,利用AVL EXCITE软件建立连杆小头轴承润滑模型,并以油膜压力、轴心轨迹及润滑油填充率确定连杆小头轴承空穴位置,研究空穴效应对连杆小头轴承润滑及动力学特性产生的影响。结果表明,在发动机整个循环工况中连杆小头轴承一直存在空穴现象。考虑空穴后平均峰值油膜压力降低了6.5 MPa,平均油膜厚度降低了1.35μm,活塞销相对连杆小头轴承的速度及加速度分别增大了1.57μm/s和0.25μm/s^(2),连杆小头轴承润滑性能减弱,所受冲击增大。

To study the influences of cavitation effect on the lubrication and dynamic characteristics of the connecting rod small end bearing,the combination of thermal elastohydrodynamic theory and flexible multi-body dynamics analysis of the piston and connecting rod assembly was used.The AVL EXCITE software was employed to establish a lubrication model for the connecting rod small head bearing.By calculating the oil film pressure,shaft trajectory and lubricant filling rate,the cavitation location of the connecting rod small end bearing was determined.The results show that there is always cavitation effect on the connecting rod small end bearing throughout the entire cycle of the engine.After considering the cavitation effect,the average peak oil film pressure of the bearing was reduced by 6.5 MPa,and the average oil film thickness was reduced by 1.35μm.The velocity and acceleration of the piston pin relative to the connecting rod small end bearing increased by 1.57μm/s and 0.25μm/s^(2),respectively,which indicates that the lubrication performance of the connecting rod small end bearing deteriorates and the impact of the bearing increases.