“溜钩”是指起重机起吊重物过程中,当将卷扬机构操纵杆置于中位后,吊钩自动下降的故障。起重机卷扬机构出现“溜钩”故障,会造成所吊物体难以就位,严重时还可能出现安全事故。本文以QY25型汽车起重机为例,根据卷扬机构液压系统工作原理,对汽车起重机“溜钩”故障进行分析,并提出检修方法。1.卷扬机构液压系统原理QY25型汽车起重机卷扬机构液压系 “Slip hook ” refers to the crane lifting heavy objects, when the winch mechanism lever is placed in the middle, the hook automatically fall fault. Crane hoisting agencies appear “slippery hook ” failure, will cause hanging objects difficult to put in place, may also be serious safety accidents. In this paper, QY25-type truck crane, for example, according to winch hydraulic system working principle, the truck crane “slip-hook ” failure analysis and proposed maintenance methods. 1. Hoisting mechanism hydraulic system principle QY25-type truck crane winch hydraulic system