某型飞机高压油滤螺钉断裂故障分析与维修对策

根据飞机高压油滤的工作原理和结构形式,结合故障现象对故障原因进行分析,确定故障与人为操作不当有关,在未安装油滤滤芯或油滤上下壳体未拧紧的情况下给液压系统增压,油滤的出口被安全活门与衬套阻断,高压油通过衬套将压力传递给垫圈,衬套在没有下壳体支撑的情况下,拉断螺钉,衬套从顶盖中下移,垫圈变形。通过故障复现试验和载荷计算,确定进出口同时供压2.8MPa或进口单独加压超过5.1MPa时,螺钉断裂。建议在油滤安装维护时,应注意油滤在飞机上安装维护要求,供压前务必确认油滤安装状态完好。

Failure Analysis and Maintenance Countermeasures of High Pressure Oil Filter Screw Fracture of a Certain Aircraft

According to the working principle and structure of an aircraft’s high pressure oil filter and combined with the failure phenomenon,the cause of the failure is analyzed,and the failure is determined to be related to improper operations as follows:the hydraulic system is pressurized when the oil filter element is not installed or the upper and lower shells of the oil filter are not tightened,and the outlet of the oil filter is blocked by the safety valve and the bushing;the high-pressure oil transmits the pressure to the gasket through the bushing,and without the support of the lower shell,the screw is broken,the bushing moves down from the top cover,and the gasket is deformed.Through failure recurrence test and load calculation,it is determined that the inlet and outlet simultaneously supply pressure of 2.8MPa or the inlet pressure exceeds 5.1MPa,and the screw will break.It is recommended that when installing and maintaining the oil filter on the aircraft,one should pay attention to the installation and maintenance requirements of the oil filter on the aircraft,and make sure that the oil filter is installed in good condition before supplying pressure.