Excavator has a wide range of operation and relatively high frequency of use. After a long period of operation, there will be varying degrees of wear and failure. Today, Xiaobian takes the long arm excavator as an example to talk about what we should do in the face of failure.

故障1:斗杆油缸的膨胀和收缩缓慢而微弱

Fault 1: the expansion and contraction of the stick cylinder are slow and weak

在长臂挖掘机工作过程中，如果斗杆油缸膨胀缓慢且薄弱，我们应进行如下检查。

During the working process of long arm excavator, if the expansion of stick cylinder is slow and weak, we should carry out the following inspection.

1.检查密封是否失效。松开低压腔的油管，释放腔内的液压油，然后启动发动机向高压腔内注入压力油。没有液压油流出低压室的油管，表明斗杆油缸的活塞密封良好。如果密封失效，低压腔和高压腔中的液压油将由于内部泄漏而相互交叉。

1. Check whether the seal is invalid. First, loosen the oil pipe in the low pressure chamber, release the hydraulic oil in the chamber, and then start the engine to inject pressure oil into the high pressure chamber. No hydraulic oil flows out of the oil pipe in the low pressure chamber, indicating that the piston of the stick cylinder is well sealed. If the seal fails, the hydraulic oil in the low pressure chamber and the high pressure chamber will cross each other due to internal leakage.

2.检查吸油阀是否正常。吸油阀是一种双向保护阀，安装在液压缸和液压马达等执行机构上。当液压缸或马达的腔产生瞬时高压时，高压腔中的高压油将打开吸油阀中的溢流阀溢流，而负压腔中吸油阀的单向阀打开，从油箱中吸油补充负压，从而保护油路。

2. Check whether the safety oil suction valve is normal. Safety suction valve is a kind of two-way protection valve, which is installed on the actuator of hydraulic cylinder and hydraulic motor. When the instantaneous high pressure is generated in the cavity of the hydraulic cylinder or motor, the high pressure oil in the high pressure cavity will open the overflow valve in the safety oil suction valve to overflow, while the one-way valve of the safety oil suction valve in the negative pressure cavity will open to absorb oil from the oil tank to supplement the negative pressure, so as to protect the oil circuit.

由于在斗杆油缸的工作回路上安装了两个吸油阀，如果一个吸油阀的单向阀不能成为双向直接连接，或者当溢流阀的溢流压力很低时，侧油腔内的油压就不能建立，压力油通过单向阀或溢流阀直接排入油箱，使斗杆油缸动作缓慢，不能甚不能工作。如果吸油阀有此故障，操作手柄处于空档位置并停止后，斗杆油缸将自动缓慢回落；相反，如果没有这种现象，吸油阀的故障可以。

Because two safety oil suction valves are installed on the working circuit of the stick cylinder, if the check valve of one safety oil suction valve cannot be directly connected in two directions, or when the overflow pressure of the relief valve is very low, the oil pressure in the side oil chamber cannot be established, and the pressure oil is directly discharged into the oil tank through the check valve or the relief valve, so that the stick cylinder moves slowly and cannot even work. If the safety suction valve has this fault, the stick cylinder will automatically and slowly fall back after the operating handle is in the neutral position and stops; on the contrary, if there is no such phenomenon, the fault of the safety suction valve can be eliminated.

3.检查PPC阀和主控制阀。PPC阀，又称先导式控制阀，是一种比例压力控制阀，它可以根据操作手柄的行程输出相应的控制压力和流量，使主控阀芯有相应的运动，从而起到控制执行器速度的作用。主控制阀中的每个阀芯控制油路的开关。如果一个阀芯磨损、卡住或甚堵塞，相应致动器的油压和流量将降低，导致致动器动作缓慢甚不动作。

3. Check PPC valve and main control valve. PPC valve, also known as pilot control valve, is a kind of proportional pressure control valve, which can output the corresponding control pressure and flow according to the stroke of the operating handle, so that the main control valve core has the corresponding movement, so as to control the speed of the actuator. Each spool in the main control valve controls the switch of the oil circuit. If a spool is worn, stuck or even blocked, the oil pressure and flow rate of the corresponding actuator will decrease, resulting in slow or even no action of the actuator.

如果斗杆油缸回路的控制油管更换为工作正常的压力控制阀，故障将消失。

If the control oil pipe of the stick cylinder circuit is replaced with a pressure control valve that works normally, the fault will disappear.

故障2:行走偏差

Fault 2: Travel Deviation

当长臂挖掘机出现跑偏故障时，应检查挖掘机组合阀。拆下限压阀上的两根油管，用塞子堵住出油口，启动发动机，用塞子组合阀和长臂挖掘机拉动行走控制手柄，检查油压是否正常；拆卸行走组合阀另一侧的两根油管，再次启动发动机，观察其限压阀的两个油孔是否有油流出。如果没有这种现象，排除组合阀的故障。

When the long arm excavator deviates, the excavator combination valve should be checked first. Remove the two oil pipes on the lower limit pressure valve, plug the oil outlet with the plug, start the engine, pull the travel control handle with the plug combination valve and the long arm excavator, and check whether the oil pressure is normal; remove the two oil pipes on the other side of the travel combination valve, start the engine again, and observe whether there is oil flowing out of the two oil holes of the pressure limit valve. If there is no such phenomenon, remove the fault of combination valve.

此时，我们应该检查旋转接头。

At this point, we should check the central swivel.

由于旋转接头处有许多油道，容易相互串通，我们可以先拆卸行走电机的两根油管，然后连接行走电机的一根油管。该动作完成后，再次起动发动机，拉动堵塞油管马达的换向阀，观察油压是否过低，液压马达的油孔是否有油流出。如果有，则认为是旋转接头的油道密封问题，更换后才能。

Because there are many oil channels at the center rotary joint, which are easy to connect with each other, we can first remove two oil pipes of the walking motor, and then connect one oil pipe of the walking motor. After the action is completed, start the engine again, pull the change-over valve blocking the oil pipe motor, and observe whether the oil pressure is too low and whether there is oil flowing out of the oil hole of the hydraulic motor. If there is, it is considered that the sealing problem of the oil passage of the central rotary joint can be solved only after replacement.

故障3:惯性旋转角度太大

Fault 3: the inertia rotation angle is too large

在增华体会国际 的过程中，由于转弯制动不及时或制动力不足，在惯性力的作用下，上部机体的转弯角度过大。鉴于这个故障问题，我们应该按如下方式处理:

In the process of increasing the long arm excavator, the turning angle of the upper body is too large under the action of inertia force due to the untimely turning braking or insufficient braking force. In view of this problem, we should deal with it as follows:

1.检查旋转锁紧阀的电路连接是否牢固，有无短路或断路，并测量电磁阀线圈和阀芯工作是否正常；

1. Check whether the circuit connection of the rotary locking valve is firm, whether there is short circuit or open circuit, and measure whether the solenoid valve coil and valve core work normally;

2.测量并检查制动油压是否在正常范围内(正常范围油压为3 MpA)；

2. Measure and check whether the brake oil pressure is in the normal range (the oil pressure in the normal range is 3 MPa);

3.拆下旋转电机，检查弹簧是否断裂，弹性是否正常，制动压盘上的密封圈是否完好。

3. Remove the rotating motor, check whether the spring is broken, whether the elasticity is normal, and whether the sealing ring on the brake pressure plate is in good condition.