某型飞机起落架舱门锁密封失效故障分析

Seal Failure Analysis of Landing Gear Compartment Door Lock in an Aircraft

起落架舱门锁用于起落架舱门的锁闭与打开,在使用过程中出现密封圈和氟塑料圈剪切损伤的情况,经分析,导致该故障的直接原因为壳体原制造缺陷,导致活塞杆运动时密封圈和氟塑料圈进入油槽,反向运动时发生剪切,间接原因为产品修理时未能发现识别密封圈和氟塑料圈损伤的情况,未考虑到壳体油槽制造偏差的风险并制定预防措施。后续在修理时增加活塞杆上的密封圈、氟塑料圈的表面质量检查及壳体油槽位置是否存在明显偏差,并对作动筒进行磨合试验。

The landing gear compartment door lock is used to shut down and open the landing gear hatch.In the process of use,the seal ring and the fluorine plastic ring occurs shear damage.By analysis,the immediate cause of the fault is the shell manufacturing defect,which causes the seal ring and the fluorine plastic ring enter the oil groove,shear occurs when the motion is reversed.The indirect cause is failure to identify damage of the seal ring and the fluorine plastic ring during the repairing.The risk of manufacturing deviation of the oil groove of the shell is not considered and preventive measures are formulated.In the subsequent repair,we add the surface quality inspection of the sealing ring and fluoroplastic ring on the piston rod and check whether there is a significant deviation in the position of the oil groove of the shell,and perform a running-in test on the actuator cylinder.