Troubleshooting the fault of weak movement of hydraulic excavators

The DH280LC-3 hydraulic excavator, after three years of use, has shown the following symptoms during operation: weak movement. It moves relatively normally on flat roads, but becomes weak when encountering resistance. It is slightly better when retreating, and it is also difficult for the machine to turn.

We conducted the inspection item by item in the order of "mechanical part first, then hydraulic system".

First, check the walking deceleration part. Since the machine has both forward and backward movements during operation, the power transmission between the walking motor and the walking drive wheel is relatively normal, the oil level and quality are also normal, and there is no external damage, the possibility of this part of the fault can be ruled out. Check the walking motor again. First, support the right track. When rotating the track, no obvious abnormal noise or jamming was found, and the left track was also relatively normal. Check the hydraulic pump. If the hydraulic pump is not working properly, it will affect all the movements of the machine. However, during operation, except for walking, all other movements of the machine are normal, and the working pressures of the front and rear hydraulic pumps are also displayed normally on the monitor. Continue to inspect the control valve. Due to the limitations of the conditions, only the size of the stroke and the flexibility of the valve stem movement are checked. Both of these items are normal. Check the center rotary joint. If there is leakage inside the center rotary joint, some of the high-pressure oil will flow into the return oil pipe when the walking resistance is large, which will also cause weak walking. Due to the internal leakage of the joint, disassembly is necessary for judgment. Therefore, this part is temporarily regarded as a suspicious point. Atlas air compressor parts.

Based on the fault phenomena of this machine and the inspection results of the above-mentioned parts, and in combination with the recent replacement of sealing parts for each working hydraulic cylinder, after a comprehensive analysis, we have made whether the center rotary joint is leaking internally the key point of the inspection. So, the rotary joint of the center was disassembled and inspected. After disassembly and inspection, it was found that most of the sealing parts on the internal rotary rotor had been damaged or fallen off, and those that were not damaged had also hardened and lost their sealing ability. After the sealing parts were replaced and the machine was reinstalled, it returned to normal.