The main manifestations of the failure:
When a Hitachi ZX330 excavator worked to 8000h, it was weak when walking on the right during construction work. It was significantly shifted to the right when straight on the flat ground, everything was normal when turning right, and it was very slow when turning left; the right walking motor was running If there is a tremor, the diesel engine needs to run at a high speed; when going uphill, the base of the right walking does not move, and everything is normal on the left.
The root cause of the failure of the Hitachi ZX330 excavator to walk on the right side:
First: Main valve: Because everything else is working normally, it is judged that the main valve is not faulty.
Second: Control valve: The control valve includes the main valve stem, variable working pressure compensation valve, valve, relay and pilot valve, etc. Control valve failures generally include the walking valve stem not moving or the stroke arrangement is small; the valve stem and valve hole The mutual cooperation gap is large, and there is internal leakage; the valve working pressure is low, and the relay control circuit is not good. This problem will cause the right walking weakness. After inspection, everything is normal for the upper and lower pilot valves. But the stroke arrangement of the main valve stem How, whether there is internal leakage, whether the valve working pressure is reduced, etc., it is difficult to determine for a while. Lengthen the up and down hydraulic oil pipes on the center connector, and interchange and connect the up and down oil pipelines. If the oil pipeline is interchanged and connected, the failure is relatively Migration, it can be judged that the control valve is faulty. The experimental result is that the right walking is still weak. According to the above inspection, there is no control valve and no control loop level to distinguish the fault.
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Third: Central connector: The central connector transfers the gear oil from the excavation part (upper end) to the walking drive equipment (bottom). If the central connector (rotary joint) leaks inside, a certain amount of high-pressure oil will flow into the return oil pipe , It may cause walking weakness. This car has been applied for 8000h, and whether there is any leakage in the center connector, it is not easy to distinguish under the condition of collapse, so it is temporarily a question.
Fourth: Right walking motor: Because it is inconvenient to listen to and touch the walking motor and hydraulic tubing when the excavator is walking, and it is not safe, so the right walking track is suspended with the bucket as the supporting point. Wait for the diesel engine When the driving wheel is not rotating, you can hear a slight "hissing" sound of the motor; when the driving wheel is not rotating, you can actually operate the handle chain rail again. After the rotation speed is increased, the speed ratio of the right walking is still much lower than all normal speed ratios, and the "hissing" sound is also increased. The same method is used to detect a part of the left walking, and the above abnormal situation is not indicated. Therefore, it is judged that there is a leakage in the right walking motor. The output torque of the motor is reduced, and the walking is weak. For the walking speed reduction equipment, because its driving force transmission is normal and there is no sound, the oil temperature, oil product, and oil volume in the speed reduction equipment are all normal, so the speed reduction equipment can be removed There is a fault.
Based on the above analysis and inspection, it was decided to disassemble and inspect the right travel motor first. After disassembling the motor, it was shown that the valve body at the support point of the valve plate was damaged seriously, and the valve body moved, causing the inlet and return fuel pipes to communicate and the working pressure oil to leak. The results are consistent. Two smooth pins are processed again, and the fault is eliminated after installation.
In short, the normal construction of the excavator requires 100% cooperation and connection with every action. This requires all owners to not only focus on the construction environment, but also closely observe the excavation during the construction process. Whether every movement of the machine is normal. Therefore, once the excavator is found to be abnormal in the course of the work, it must not be forcibly constructed in order to catch up with the construction period, but a thorough excavator maintenance inspection must be done. Otherwise, the construction period is overdue, but the excavation opportunities will have more serious failures, and it will be too late if I really regret it!
