一种类似于液压起重机回转的作业平台在生产组装后,调试中出现左边支腿缸伸不出来、右边支腿缸伸缩正常的情况。甚至出现左边支腿缸伸出一段后停止,待操纵阀回中位后该缸又回缩的现象。多次操作后,操纵阀出现油路串通等情况(左、右支腿油路完全相同)。更换操纵阀后情况并没有改变,更换左边支腿缸后情况也没有改变。此时发现,右边支腿缸出现自动伸出的状况, A similar operation of the hydraulic crane rotary platform in the production and assembly, the debugging appears in the left leg cylinder stretched out, the right leg cylinder telescopic normal situation. Even left leg cylinder cylinder after a stop, to be manipulated valve back to the center after the contraction of the cylinder phenomenon. After many operations, control valve appears collusion and other conditions (left and right legs exactly the same circuit). The condition has not changed after changing the control valve, and the situation has not changed after replacing the left leg cylinder. At this time found that the right leg cylinder appears automatically extended the situation,