一台WY32型挖掘机，在施工过程中出现斗杆缸工作乏力并自然下垂现象。起初怀疑是液压缸内泄，但更换活塞组合密封后故障现象仍然存在，经压力测试，认为是由于组合阀组的阀芯内泄所致。为了验证上述判断，我们将该阀组拆下清洗，并将其各控制阀口朝上平放，然后向各个控制口注 In a WY32 excavator, there was a lack of force in the arm cylinder during the construction process and the phenomenon of natural sagging. At first, it was suspected that the hydraulic cylinder was leaking, but the phenomenon of failure still existed after the replacement of the piston combination seal. After the pressure test, it was thought that it was due to the leakage of the valve core of the combination valve group. In order to verify the above judgment, we will remove and clean the valve group, and place each control valve port upward, and then note to each control port.