发动机连杆轴承摩擦润滑过程动态仿真研究

Dynamic Simulation Research on the Friction Lubrication Process of Engine Connecting Rod Bearings

以某重型柴油机的连杆轴承为研究对象,通过仿真计算发现Singhal、Schnerr and Sauer及Zwart-Gerber-Belamri这3种空化模型中,Singhal模型对峰值压力更敏感,用该空化模型探究了进油口位置对空化范围的影响及轴颈和轴瓦之间径向相对运动对油膜空化的影响。结果表明:对于稳态计算模型,沿着轴颈转动方向,最小油膜厚度下游侧出现显著的空化现象,且空化范围受到最小油膜厚度和进油口之间范围的影响;而在动态仿真过程中,当轴间隙减小时,峰值压力逐步增加,在最小轴间隙(1μm)处达到最大(187 MPa);当轴间隙增大时,峰值压力突降,此时在最小油膜厚度下游处将发生显著空化;空化主要发生和消失的过程均发生在轴颈远离轴瓦的过程中,其中当轴间隙约为40μm时空化最为剧烈;随着轴间隙进一步增加,空化程度逐渐减弱,在轴间隙约为110μm时空化消失。

Taking the connecting rod bearing as the research object,through simulation calculation,it was found that among the three cavitation models Singhal,Schnerr and Sauer and Zwart-Gerber-Belamri,the Singhal was more sensitive to the peak pressure. And Singhal was used to study the influence of the position of the oil inlet on the cavitation range and the influence of the radial relative motion between the journal and bush on the oil film cavitation. Results show that in steady state simulation,along the rotation direction of the journal,the cavitation phenomenon is obvious on the downstream of the minimum oil film thickness,and the cavitation range is affected by the range between the minimum oil film thickness and the oil inlet. In the transient state simulation, when the shaft clearance decreases, the peak pressure increases gradually, and reaches the maximum(187 MPa) at the minimum oil film thickness(1 μm). When the shaft clearance increases,the peak pressure drops suddenly. In this process,significant cavitation will occur in the downstream of the minimum oil film. Cavitation mainly occurs and disappears when the journal moves away from the bush.When the shaft clearance is about 40 μm,the cavitation is the most severe. With the further increase of the shaft clearance,the cavitation degree gradually decreases. When the shaft clearance reaches about 110 μm,the cavitation disappears.