柴油机曲轴前油封密封性能分析及优化设计

Sealing Performance Analysis and Optimization Design of Front-end Oil Seal of Diesel Engine

利用ABAQUS软件建立某柴油机曲轴前油封的二维轴对称模型,在静态条件下计算分析油封材料参数、安装过盈量、前唇角以及后唇角对油封唇口最大Von Mises应力、接触压力及其分布的影响。结果表明,随橡胶硬度的增加,唇口最大接触压力几乎呈线性增长,适当提高橡胶硬度可改善密封性能;在曲轴未接触防尘唇前,唇口接触压力随安装过盈量的增大逐渐增大,当曲轴接触油封防尘唇后,油封密封唇口接触压力将减小,因此,在曲轴不接触油封的前提下应选择较大的安装过盈量;当前唇角为45°时,唇口最大接触压力取得最大值,而随后唇角的增加,唇口接触压力呈增大趋势。根据计算结果,对初始曲轴油封的材料和结构进行优化设计。试验证明,改进后的油封具有更好的密封性能。

The two-dimensional axial symmetric finite element model of the front-end oil seal of a diesel engine was estab- lished by using ABAQUS. The effects of the material parameters, the amount of interference, and the low-angle and high-angle on the Von Mises stress,the size and distribution of the oil seal contact pressure under static conditions were analyzed and calculated. The results show that, along with increasing of rubber hardness, the max contact pressure on the lip is increased almost linearly. Sealing performance can be improved by suitably increasing rubber hardness. The contact pressure on the lip is increased gradually along with increasing of the amount of interference before the contact of crankshaft with dust-proof lip, and after that the contact pressure is decreased. Therefore, the larger value of interference must be chosen in the premise that the crankshaft is not in contact with the dust-proof lip. The maximum contact pressure value is reached the maximum value when the low-angle is at 45°,While along with increasing of the high-angle ,the contact pressure along the lip is increased. According to the calculation results, the material and structure of the original oil seal of crankshaft were optimized and designed. It is proved by experiments that the improved oil seal has better sealing performance.