1.伸缩臂自动回缩1台新装机的QY25型汽车起重机伸缩臂伸出后,当伸缩手柄处于中位时出现缓慢自动回缩现象。(1)伸缩臂液压控制原理伸缩臂液压控制原理如图1所示,从其工作原理可以看出,当操纵手柄处于中位时,由于平衡阀处于关闭状态,无杆腔的油液被平衡阀封住,不能外泄,伸缩缸处于静止不动状态。只有当平衡阀有故障或伸缩缸密封件磨损时,吊臂才会出现缓慢自动回缩现象。 1. Telescopic automatic retraction A newly installed QY25 truck crane telescopic arm stretched out, when the retractable handle in the middle of a slow automatic retraction phenomenon. (1) Telescopic hydraulic control principle Telescopic hydraulic control principle shown in Figure 1, from its working principle can be seen, when the joystick in the middle, due to the balance valve is closed, the rodless chamber of the oil is balanced Valve seal, can not be leaked, telescopic cylinder in a stationary state. Only when the balance valve is defective or the telescopic cylinder seals wear out, the boom will slowly and automatically retract.