Maintenance method of excavator running deviation
The excavator travels in a straight line for 20m. If the deviation exceeds 200mm, it indicates that the excavator has a walking deviation fault. The main pump, main travel valve, central swivel, travel motor, travel pilot valve and other components of the excavator have faults, as well as the tension of the crawler, which will cause its travel deviation. The specific maintenance parts and methods are as follows.
(1) Main pump
The excavator adopts double main pumps. If there are differences in the outlet pressure of the main pumps on both sides of the excavator, the overflow pressure of the overflow valve of the main pump and the adjustment of the main pump regulator, the swing angle of the swashplates of the main pumps on both sides is not synchronized or the parts are worn differently, the flow or pressure of the main pumps on both sides will deviate, resulting in the deviation of the excavator.
The maintenance methods are as follows: check whether the outlet pressure of the main pump is normal through the display. If the pressure of the excavator working device (moving bamboo, bucket and bucket) and the slewing device is normal during operation, the possibility of failure of the hydraulic pump can be eliminated; After exchanging the high-pressure oil pipes of the two main pumps, test the machine. If the excavator deviates in the opposite direction, it can be determined that the main pump on the side of slow travel is faulty; The traveling motors on both sides of the excavator are tested with the method of single pump oil supply. If the excavator does not deviate, it can also be determined that the main pump on the side of slow traveling is faulty. Dismantle the main pump with fault, replace the damaged parts, and reassemble it after commissioning on the test bench.
(2) Travel main valve
The main valve core of excavator travel is stuck, and the spring in the valve is soft or broken, which can cause the failure of excavator travel action and lead to the deviation of excavator travel.
The maintenance methods are as follows: exchange the high-pressure oil pipes of the two main pumps, and exchange the central swivel with the four high-pressure hoses connected to the main traveling valve before commissioning. If the excavator deviates in the opposite direction, it can be determined that the valve core of the main traveling valve has failed to act; Measure the overflow pressure of the traveling main valve. If the overflow pressure does not meet the requirements, it can be determined that the valve core of the traveling main valve is faulty. Remove the faulty valve core of the traveling main valve, check whether the spring is soft or broken, and whether there is foreign matter in the valve, and then clean the valve core and replace the damaged parts.
(3) Travel motor
If the safety overflow valve of the traveling motor leaks oil, the oil pressure of the traveling hydraulic system will be too low, resulting in the speed drop of the traveling motor and the traveling deviation of the excavator.
The maintenance method is as follows: exchange the relief valves installed on the left and right travel motors. If the fault phenomenon is opposite, it can be determined that the safety relief valve of the travel motor is faulty. Replace the damaged travel motor safety relief valve.
(4) Blocked oil circuit
If the balance valve orifice in the parking brake oil circuit on one side is blocked by foreign matters, the pressure oil cannot enter the balance valve through the orifice to push its valve core to move, resulting in the parking brake cannot be released, the travel motor cannot rotate, and the excavator has a travel deviation fault.
If the throttling oil circuit of the excavator to release the brake is blocked by foreign matters, the parking brake can not be released, resulting in the failure of the travel motor to rotate and the traveling deviation fault of the excavator. The throttling oil circuit to release the brake is shown in Figure 4.
The maintenance method is as follows: exchange the four high-pressure hoses connected between the central swivel of the excavator and the travel motor, and test the machine. If the fault phenomenon remains unchanged, it can be determined that there is a fault in the travel deceleration mechanism or the travel motor. After exchanging the safety relief valves of the left and right travel motors, the machine can be tested. If the fault does not change, it may be that the balance valve or the brake oil circuit is blocked. It is necessary to clean the balance valve or remove the brake oil circuit, avoid foreign matters from entering the oil circuit during disassembly and assembly, and replace the hydraulic oil and filter element.
(5) Travel pilot valve
The travel pilot valve can output corresponding pressure oil according to the stroke of the joystick, so that the main control valve can generate corresponding movement, so as to control the travel speed of the excavator. If the output oil pressure of the travel pilot valve on both sides is inconsistent, or the valve core of the pilot valve on one side is stuck by foreign matters, it can cause the excavator travel deviation.
The maintenance method is as follows: measure the oil pressure of the travel pilot valve. If the output oil pressure of the travel pilot valves on both sides is inconsistent, it can be determined that the travel pilot valve is faulty; Disassemble and clean the pilot valve and relevant oil circuit, and replace the hydraulic oil and filter element.
In addition, if the tension of the left and right crawlers of the excavator is not the same, it may also cause the excavator to deviate. If the tension of the tracks on both sides is inconsistent, add grease to the track tensioner on the loose side to make it consistent with the tension on the other side.
