丁腈橡胶O形密封圈失效原因分析

针对飞机油滤系统漏油故障,通过丁腈橡胶O形密封圈外观质量、尺寸、性能、胶料组分和微观形貌测试,分析O形圈失效原因。结果表明:O形圈表面凹痕与O形圈承压能力和装配间隙有关;O形圈内部存在的分层痕迹和异物与生产过程控制不到位有关;O形圈在液压油环境中受到外力作用是其失效的主要原因,破坏形式为疲劳破坏。设定合理的密封压缩量和装配间隙、保证贮存和硫化环境符合要求、提高O形圈密封面加工质量等措施可以预防O形圈失效。

Analysis on Failure Cause of NBR O-Ring

In this work,the leakage of aircraft oil filter system was investigated and the causes of acrylonitrile-butadiene rubber O-ring failure were analyzed by visual inspection,dimension measurement,performance test,compound composition analysis and micro morphology analysis of the O-rings.The results showed that,the surface indentation was related to the pressure bearing capacity and assembly clearance of the O-ring.There were stratified traces and foreign matters in the O-rings,which were related to the inadequate control of the production process.The main reason of the failure of O-ring was the external force in the hydraulic oil environment,and the failure mode was fatigue failure.The failure of O-ring could be prevented by setting reasonable sealing compression and assembly clearance,ensuring the storage and curing environment according to requirements,and improving the processing quality of O-ring sealing surface.