内燃机曲轴密封的结构分析和材料工艺研究

Structure Analysis and Material Technology Study of ICE Crankshaft Seal

建立了油封的非线性有限元模型,分析不同结构的油封与轴过盈配合时的接触压应力分布和变形情况,并计算了密封面之间的油泄漏量,为油封的结构设计提供理论依据。研究了烧结工艺对聚四氟乙烯复合材料力学性能的影响,结果表明:设计合理的PTFE油封必须使压力上升段与压力下降段的最大梯度相差不大、接触应力曲线平缓且呈扁平形分布,从而使密封面之间不容易产生动压力,由压差造成的油液流量小;材料的回复性是影响油封密封性的重要因素,无须单纯追求提高压缩模量和伸长率等。

The nonlinear finite element model of oil seal was established, the contact compressive stress distribution and deformation of interference fit between oil seal and axis which had different structures were analyzed and the leakage between oil seal surfaces was calculated which offered theoretical reference for oil seal structure design. The influence of sintering technology on PTFE mechanical performance was further researched. The results show that the appropriate PTFE oil seal must have a small difference between the maximum gradients of pressure rise segment and pressure fall segment and have gentle and flat distribution, which makes dynamic pressure hardly occur between seal surfaces and the flow caused by pressure difference small. It is also proved that the material elasticity recovery is the main factor influencing sealing performance and its improvement is not only the increase of compression modulus and elongation.