起落架缓冲器掉压及油液微量泄漏故障分析

Failure Analysis of Landing Gear Buffer Pressure Drop and Oil Microleakage

缓冲器是起落架的重要组成部件之一,在飞机起飞着陆时起着缓冲、减震的作用。针对外场一架起落架的油液-氮气式缓冲器掉压及油液微量泄漏故障,通过故障复现、尺寸检测、故障定位等,分析出该故障是由于缓冲器中外筒铬层窜气及装配试验过程中余油未排净而造成的,可通过提高外筒镀覆质量,增加铬层气密检查,排除铬层窜气故障;在确保密封组件尺寸合格、密封性能达标的前提下,只须在装配后增加清除外筒孔口至密封部位环形空腔内残留液压油的工艺安排,即可彻底消除缓冲器掉压及油液微量泄漏故障。该分析故障的方法同样可用于其他零部件失效分析。为了进一步方便此类故障的分析和排查,可对缓冲器类漏油问题建立故障树,健全排故方案,搭建起落架维护手册。

The buffer was one of the important components of landing gear,which played a role of cushion and shock absorption during take-off and landing.Aimed at faults of oil-nitrogen type buffer pressure drop and oil microleakage leakage fault of outfield landing gear,through the fault repetition,size detection,fault location,etc.,it was analyzed that the failure was due to buffer external barrel chrome layer gas channeling and residual oil not free during assembly test.By raising the outer barrel plating quality,adding inspection in the chrome layer,eliminating chromium layer gas channeling fault,and on the premise of ensuring the qualified size and sealing performance of the sealing assembly,the residual hydraulic oil in the annular cavity between the orifite of the outer cylinder and the sealing part was removed completely by adding the technological arrangement after assembly,by doing that,the buffer pressure drop and oil microleakage faults could be completely eliminate.The method of fault analysis could also be applied to failure analysis of other parts.In order to further facilitate the analysis and troubleshooting of such faults,the fault tree could be established for buffer oil leakage problems,and perfected the trouble removal scheme,so as to build landing gear maintenance manual.