液压汽车起重机工作时,载荷和全车重量完全靠四条支腿支撑。如果某条支腿支持不住,发生“软腿”,就会引起事故。我们接触过的液压汽车起重机中,泰山牌QY5型发生“软腿”的现象较多。本文就存在的问题,提出改进意见,供有关部门参考。所谓“软腿”就是支腿液压缸承受较大载荷时,活塞杆发生自行收缩的现象。为了防止发生活塞杆自行收缩,支腿缸一般都安装了双向液压锁,防止缸内液压油向外泄漏。只要液压锁性能符合要求,支腿就能可靠地工作;液压 When the hydraulic truck crane is working, the load and the entire vehicle weight are supported by four legs. If an outrigger doesn’t support it, a “soft leg” will cause an accident. Among the hydraulic truck cranes that we have contacted, the “soft leg” phenomenon has occurred in the QY5 type of the Taishan brand. This paper proposes suggestions for improvement on existing problems for the reference of related departments. The so-called “soft leg” is a phenomenon in which the piston rod self-shrinks when the leg hydraulic cylinder is subjected to a large load. In order to prevent the piston rod from shrinking, the leg cylinder is generally equipped with a bi-directional hydraulic lock to prevent the hydraulic oil in the cylinder from leaking out. As long as the performance of the hydraulic lock meets the requirements, the legs can work reliably;