Cause analysis and inspection methods of several common hydraulic system faults of Komatsu excavator, including insufficient pressure of excavator, insufficient power of excavator, falling and shaking of excavator boom, etc.
1. The excavator has insufficient power. There are two types of situations: one is insufficient power for boom, bucket and right travel. The analysis shows that the overflow valve on one side of the main pump is out of order. Adjust the pressure or replace the overflow valve as required after patrol inspection and verification; If the power of stick, swing and left travel is insufficient, the overflow valve on the other main pump side may fail. After inspection and verification, adjust the pressure or replace the valve as required.
2. The excavator pressure is insufficient. It is found that the function of the main overflow valve fails, which makes it impossible for the hydraulic system to establish a normal working pressure. At this time, the pressure of the main overflow valve can be inspected, and then the valve can be adjusted or replaced according to the specified pressure.
3. When the excavator pilot valve is in the neutral position, the boom, stick and bucket move quickly to the no-load side, such as boom lowering, bucket opening, etc. The reason may be that the overflow valve at the oil port opens when the pressure is lower than the specified pressure, which makes the pressure of the overflow valve at the oil port unable to support the load of the hydraulic cylinder. The crawling condition of the hydraulic cylinder can be inspected when the pilot operated valve is in the neutral position. If the measured value of the hydraulic cylinder has exceeded the specified value, check the pressure of the oil port overflow valve and adjust or replace it according to the regulations.
4. The power of a part of the excavator working device is insufficient. This may be due to the failure of the oil port relief valve in the faulty oil circuit. Inspect the pressure of the oil outlet overflow valve in the faulty oil circuit, and then adjust the pressure or replace the valve as required. If the actions (retraction and extension) on both sides of the machine lack sufficient power, check the oil filter in the oil tank. There may be broken seals in the oil filter. Clean the oil filter and replace the seal.
