Due to maintenance or actual operation factors, many customers' excavation opportunities have misaligned walking problems. Once people encounter excavator misalignment during work, how should the excavator maintenance master find the cause and troubleshoot?
1 Central rotary joint seal ring damage. The central rotary joint is composed of a casing and a core rod. The core rod is installed on the lower car body, and the cover is installed on the upper car body. The core rod has the same annular pipe groove as the oil pipeline. The hydraulic oil from the main valve core flows into the motor from the vertical hole on the mandrel through the cover, and the cover rotates continuously with the upper body. The pipe groove on the mandrel can also be smooth with the oil hole on the cover. The hydraulic oil Can freely enter and exit on the connection head of the management center. If the filter element of the hydraulic oil is not removed and replaced early, the intake valve on the filter element will open, and the residue in the oil will enter the drag surface of the rotary joint of the management center as soon as possible, so that the The seal ring is damaged. When the excavator is walking, the working pressure oil on one side of the excavator leaks, and the speed of the two walking motors is different. As a result, the excavator runs off track. The troubleshooting method is: when removing and replacing the oil on the center rotary joint, additionally remove and replace the hydraulic oil and filter element.
2 Foreign matter enters the balance valve in the fuel pipe of the parking brake system on the side of the excavator. Once a foreign matter blocks the small round hole of the balance valve when the excavator is walking, the parking brake system cannot be eliminated, so walking and running will occur. However, this is because when the excavator is walking, if the working pressure oil cannot use the small round hole of the balance valve to enter the yellow chamber of the balance valve to promote the movement of the valve center of the balance valve, the working pressure oil cannot rely on the balance valve. When the trough enters its hydraulic transmission system, the driving force of the parking brake cannot be eliminated. As a result, the walking motor cannot be rotated, which will cause the walking deviation. Troubleshooting method: Remove the balance valve and clean it. When disassembling, no waste should enter; disassemble and replace the hydraulic oil and filter element that meet the requirements as soon as possible.
3 Oil seepage in the travel motor valve Oil seepage in the travel motor valve will cause the operating pressure in the system to be too low and the travel motor will not rotate enough, which will result in running deviation.
Troubleshooting method: dismantle and replace the valve of the walking motor that has long been destroyed. When distinguishing, it is necessary to exchange the valves of the up and down traveling motor to see if it is offset when traveling in the opposite direction.
4 The waste blocks the small round hole K of the balance valve of the final drive device, and the parking brake system cannot eliminate the excavator. When the excavator is walking, if the working pressure oil does not use the small round hole K on the balance valve to promote the valve center of the balance valve When moving, the working pressure oil cannot use the groove on the balance valve to eliminate the driving force of parking, and the walking motor cannot rotate normally, and the excavator will run off the track. Troubleshooting method: Clean the oil circuit, and pay special attention to prevent dirty things from entering in the future when disassembling, and to remove and replace the hydraulic oil and filter element on time.
5 The posture of the valve core of the excavator's offset walking main valve is not working properly. Once the spring in the walking main valve becomes loose or broken, or the valve core is stuck, there will often be a reduction in vapor pressure and a deviation in walking. During the inspection, the working pressure of the fuel pipe of the walking main valve should be accurately measured. The standard value is 30.5MPa. Once the walking main valve is destroyed, it needs to be replaced or repaired. People have encountered Doosan DH220LC-V excavators running off track. The result of the inspection is If the main valve is damaged, if the main valve core is damaged, the main valve core of the excavator should be damaged. 6 The suction valve on the offset side of the excavator destroys the oil suction valve and the hydraulic cylinder and the equipment installed in the working equipment. On the motor. The effect is: when the hydraulic cylinder or motor is subject to extreme external shocks, the abnormal high pressure in the hydraulic cylinder or motor can be removed, so the maintenance related oil pipelines and cylinders will not be damaged. Once the travel suction valve is destroyed, the valve is yellow, soft or broken, the vapor pressure in the travel main valve will be reduced, and the driving force of the travel motor will be insufficient and deviation will occur. Troubleshooting method: repair or replace the suction valve.
7 The chain rail tension level is different once the excavator is walking, the chain rail tension level on the upper and lower sides is different, which will also cause deviation when walking. Fault detection: Fill the loose side with unsalted butter to make it the same degree of tension as the other side.
8 Gasoline pump characteristics are reduced. When the excavator runs in parallel, when the plunger pump of the pump total flow controller of one of the pumps is stuck in a certain position, or because the damage is serious, the internal leakage occurs, and the working pressure of the system software is only Exceeding 29.5 MPa, the speed of the walking motor is very slow, and the excavator may deviate. Troubleshooting method: Remove the hydraulic oil pump from the excavator, replace the damaged parts, repair the controller, and replace the hydraulic oil and filter element.
The output working pressure of the walking proportional valve on the offset side of the excavator is too low. The proportional valve needs to output the relative control steam pressure according to the length of the control lever control stroke arrangement, so that the main pressure regulating valve has a relative displacement, so the control is working The speed of the device. Once the filter element of the oil filter cannot be changed on time, the filter element will be blocked, and the intake valve of the oil filter will be opened. The blackened hydraulic oil enters the control circuit of the proportional valve as soon as possible under the condition of no consideration, and appears inside the valve. If the electro-hydraulic reversing valve is jammed, the operating oil cannot flow through the rotary proportional valve on the offset side of the excavator to the rotary main pressure regulating valve, and the walking deviation occurs. At this time, check the working pressure (3.3MPa) of the walking proportional valve. Troubleshooting method: clean the oil circuit board and the fuel pipe in front of the phase, dismantle and replace the hydraulic oil and filter element.
summary:
In the application of the excavator, the appropriate hydraulic oil must be used according to the instructions for use, and special attention should be paid to ensure the cleanliness of the hydraulic oil to avoid environmental pollution when changing the oil; in addition, the hydraulic oil and filter element should be removed and replaced as soon as possible in accordance with the regulations. Only then can the excavator have fewer problems and increase its service life.
