The reason for the failure of Komatsu PC130-8M0 excavator to walk should be known. Of course, there are many types of failure. This article will use examples to describe the reasons for the failure of the excavator to walk on the left side and the maintenance methods.
Specific details: The operator learned that the bucket cylinder oil seal of the excavator was broken, causing oil pollution Dismantle the oil pipe and each valve element of the main control valve, clean them and reassemble the test machine. The left side of the machine still cannot walk.
Analysis of excavator repair:
1. The left traveling main valve of the excavator is stuck,
2. The left travel pilot valve of the excavator is faulty,
3. There is a problem with the traveling balance valve on the left side of the excavator,
4. The straight travel valve of the excavator is faulty,
5. The excavator traveling motor or reducer is faulty
6. The left traveling oil path at the rotary joint of the excavator center is connected,
Troubleshooting:
First, check the left pilot oil pressure. It is normal to measure the output oil pressure of the left travel pilot valve to 3.5MPa with a pressure gauge on site The left and right pilot pressure oil pipes were exchanged for testing, and the failure was still the same, thus eliminating the possibility of failure of the pilot valve.
Disassemble and check the left side main travel valve. Other functions of the machine are normal, indicating that the main pump controlling the left side travel is normal. Disassemble the left side main travel valve, move the valve core of the main valve manually, and feel that the valve core slides freely without jamming. Clean the left side main travel valve for many times, and test the machine after reassembly. The fault still exists.
Check the balance valve and safety valve, remove the left travel motor, remove the central transmission shaft of the reducer, remove the balance valve for cleaning, and then reinstall it for testing. The machine still cannot travel. Remove the two safety valves on the left motor and replace the safety valves on the right travel motor, and the failure remains after testing.
Disassemble and inspect the linear travel valve. It is analyzed that if the left travel valve element is normal, the high-pressure oil pipe directly connected to the travel motor should have a large amount of pressure oil when operating the excavator to travel left. When removing one oil pipe on the left travel motor, almost no oil flows out of the oil pipe when operating the excavator to travel. Although oil flows out of the oil pipe when operating in the opposite direction, the pressure is very low (oil return pressure). Considering that each valve element has been disassembled, It may be that the installation direction of the valve element of the linear travel valve is wrong. After the valve element of the linear travel valve is reversely installed and tested, the fault of the machine disappears.
The faults in this example are caused by the wrong installation of the valve element. The reason is that the installation direction and position of the valve element were not paid attention to when the valve element was disassembled for cleaning or inspection Therefore, during the disassembly of hydraulic components, the installation direction, order and position of each component must be kept in mind, and components must not be lost, wrongly installed or omitted, otherwise old faults may not be eliminated and new faults may be added.
