升降货梯http://m.iyunsun.com/启闭机能正常启、闭闸门，说明控制阀组及液压站各项功能基本正常；闸门开启后下滑量严重超标，说明启闭机液压系统存在较为严重的泄漏；无外漏油现象，说明泄漏存在于启闭机液压系统内部。根据故障现象和检查情况分析，泄漏部位应在液压缸和控制阀组。

1、由于升降货梯启闭机运行时间较长，液压缸密封环和支承结构破坏、磨损、老化以及缸筒内壁拉伤是造成液压缸内泄漏的主要原因。闸门被提升并锁定于开闸位置后，液压系统停止工作，液压缸进出油道均被切断，液压缸有杆腔在闸门自重作用下会建立起一定油压力，而无杆腔有体积增大倾向，油压相对外较低，两油腔间会形成一压差。
Because cargo lifter hoist run longer, hydraulic cylinder seal ring and bearing structural damage, wear, aging and injury is caused by the inner wall of the cylinder hydraulic cylinder leakage main reason. After the gate is raised and locked in the gate position, the hydraulic system to stop working, hydraulic cylinders are cut out of the oil passages, hydraulic cylinder rod chamber gate under its own weight in certain oil pressure will build, without the rod cavity volume increases tendencies, low oil pressure relative to the outer, will form a pressure differential between the two oil chamber.

2、升降货梯启闭机提升闸门至开闸位置后，液压缸是利用二位插装换向阀阀芯密封锥面作锁定。二位插装换向阀阀芯锥面多次动作后会有一定量的磨损; 阀芯锥面一侧为有杆腔压力油，油压较高，另一侧为冋油道，油压基本为零；在压差作用下，液压缸有杆腔高压油会通过磨损处泄漏回油箱，形成系统泄漏，使液压缸有杆腔体积减小，活塞下移，表现为闸门下滑。
Cargo lifter hoist lifting gate to gate position, the hydraulic cylinder is the use of two sealed cartridge spool valve cone as locked. Cartridge valve spool two cone after repeated actions will have a certain amount of wear and tear;spool cone rod chamber pressure side for oil, high oil pressure, the other side of the road for Jiong oil, hydraulic basic zero; in effect under pressure, hydraulic cylinder rod chamber pressure oil will leak back to the tank through the fray to form a system leak, the hydraulic cylinder rod chamber volume decreases, the piston down, the performance of the gate fell.

3、在年久失修下滑量较大的升降货梯http://m.iyunsun.com/液压启闭机中，一般液压缸内泄漏和系统泄漏同时存在，本启闭机两种泄漏情况都存在，以液压缸内泄漏为主，系统泄漏为辅。
Decline in disrepair large amount of cargo lifter hydraulic hoist, in general, the hydraulic cylinder leaks and system leaks exist, this hoist two kinds of leaks are present, the main hydraulic cylinder leak, the system for leaks auxiliary.