吊车的液压阀是调控吊车运行压力的重要配件，因此，我们一定要对吊车的液压阀进行良好的了解，详细了解吊车的液压阀是否能够起到减压的作用，才可以让吊车的运行质量变得更加的优秀。
The hydraulic valve of the crane is an important accessory to control the pressure of the crane. Therefore, we must have a good understanding of the hydraulic valve of the crane, and know in detail whether the hydraulic valve of the crane can reduce the pressure, so as to make the operation quality of the crane more excellent.
那么，究竟有哪些原因会导致吊车的液压阀无法起到减压的作用呢？就让我们一起来了解一下：
So, what are the reasons that make the hydraulic valve of the crane unable to reduce pressure? Let's understand:
1、吊车的先导阀上阻尼孔堵塞。该孔堵塞后，先导阀不起控制作用，而出口压力油液通过主阀内阻尼孔充人主阀上腔，主阀芯在弹簧作用下，处于最下端位置，阀口一直大 开，故阀不起减压作用，进出口压力同步上升或下降。
1. The damping hole on the pilot valve of the crane is blocked. After the hole is blocked, the pilot valve does not play a control role, and the outlet pressure oil fills the upper chamber of the main valve through the internal choke hole of the main valve. Under the action of spring, the main valve core is at the bottom position, and the valve port is always wide open, so the valve does not play a role in reducing pressure, and the inlet and outlet pressure rises or falls synchronously.
2、泄油口堵塞。该口堵塞后，吊车先导阀无法泄油，不能工作的后果与先导阀上阻尼孔堵塞一样，故进出口油压也是同步上升或下降。
2. The drain port is blocked. After this port is blocked, the pilot valve of the crane can not drain oil, and the consequence of not working is the same as that of blocking the damping hole on the pilot valve, so the oil pressure at the inlet and outlet also rises or falls synchronously.
3、吊车主阀芯在全开状态下被卡死，也会造成液压阀无法减压的情况出现。
3. When the main valve core of the crane is stuck in the fully open state, the hydraulic valve can not reduce pressure.