柴油机曲轴油封密封失效机理分析及改进

徐统伟，于涵，刘佳，贾德民

潍柴动力股份有限公司，山东 潍坊  261061

摘要：为降低柴油机曲轴油封密封失效故障率，统计分析某平台柴油机曲轴油封的市场故障数据，利用鱼骨图从人、机器、材料、方法、环境、测量6方面分析油封密封失效漏油的可能原因，通过不同供应商油封可靠性台架对比试验和油封一致性考核台架试验验证失效根本原因；在此基础上提出改进措施并进行改进后的市场跟踪验证。结果表明：水泥搅拌车用油封的故障率最高，后油封的故障率显著高于前油封；故障油封的主要失效模式包括主唇线故障、偏磨和毛毡起毛；油封随动性与胶料致密度不足、生产装配工艺缺陷、端盖及齿轮轴端面未涂胶、组合式油封可装配性差是密封失效的根本原因。采取优化油封参数、注射硫化工艺、在端盖和齿轮轴头端涂胶、改进装配工艺等改进措施后，油封市场故障率明显降低。

关键词：柴油机；油封；密封失效；耐久试验；改进措施

Analysis on the sealing failure of a diesel engine crankshaft oil seal and its improvement

XU Tongwei, YU Han, LIU Jia, JIA Demin

Weichai Power Co., Ltd., Weifang 261061, China

Abstract: To reduce the seal failure rate of diesel engine crankshaft oil seals, market failure data of a certain platform′s diesel engine crankshaft oil seals is statistically analyzed. Using fishbone diagrams, possible causes of oil seal failure and leakage are analyzed from six aspects: human, machine, material, method, environment, and measurement. The root cause of failure is verified through comparative tests of oil seal reliability from different suppliers and oil seal consistency assessment bench tests. On this basis, the improvement measures to reduce the sealing failure rate are proposed and tracked in the market. The results show that the failure rate of oil seals for cement mixer trucks is the highest, and the failure rate of the rear oil seal is significantly higher than that of the front oil seal. The main failure modes of faulty oil seals include main lip line failure, eccentric wear, and felt fuzzing. The main reasons for seal failure are the insufficient of followability of the oil seal and the inadequate density of the rubber material, defective production assembly process, uncoated end caps and gear shaft end faces, and poor assembly performance of combination oil seals. The oil seal parameters are optimized, as well as the injection vulcanization process, gluing on end caps and gear shaft heads, and assembly processes. After improvement, the failure rate of the oil seal market has significantly decreased.

Keywords: diesel engine; oil seal; seal failure; durability test; improvement measure