Excavator walking deviation maintenance method
The excavator travels straight for 20m. If the deviation exceeds 200mm, it means that the excavator has a walking deviation problem. Excavator main pump, walking main valve, central rotary joint, walking motor, walking pilot valve and other components are faulty, and the tension of the crawler is problematic, which will cause their walking deviation. The specific repair parts and methods are as follows.
(1) Main pump
The excavator adopts double main pumps. If there are differences between the main pump outlet pressure on both sides of the excavator, the main pump overflow valve overflow pressure, and the adjustment of the main pump regulator, the swash plate swing angles of the main pumps on both sides are not synchronized or the parts are worn. Differences will cause deviations in the flow or pressure of the main pumps on both sides, causing the excavator to run away.
The maintenance method is as follows: you can check whether the main pump outlet pressure is normal through the display. If the working pressure of the excavator working device (moving bamboo, stick, bucket) and the slewing device is normal, the possibility of failure of the hydraulic pump can be ruled out; 2 Test the machine after the high-pressure oil pipes of the main pump are exchanged. If the excavator runs in the opposite direction, it can be judged that the main pump on the slow walking side is faulty; use the single pump oil supply method on both sides of the excavator to test the machine. If the excavator does not Deviations can also determine that the main pump on the slow walking side is defective. Remove the faulty main pump, replace the damaged parts, and install them again after passing the debugging on the test stand.
(2) Walking main valve
The main valve spool of excavator is stuck, and the spring in the valve is soft or broken, which can cause the excavator to fail to move and cause the excavator to drift.
The maintenance method is as follows: the high-pressure oil pipes of the two main pumps are exchanged, and the four high-pressure hoses connected to the central rotary joint and the walking main valve are interchanged. The spool action fails; measure the overflow pressure of the walking main valve. If the overflow pressure does not meet the requirements, it can be judged that the walking main valve spool is faulty. Remove the faulty walking main valve spool, check whether the spring is soft or broken, and whether there is foreign matter in the valve, then clean the spool and replace the damaged parts.
(3) Walking motor
If the safety relief valve of the travel motor leaks oil, it will cause the hydraulic pressure of the travel hydraulic system to be too low, causing the speed of the travel motor to drop and the excavator to run away.
The maintenance method is as follows: replace the relief valves of the left and right travel motors. If the fault phenomenon is opposite, it can be determined that the travel motor safety relief valve is faulty. Just replace the damaged safety relief valve of the walking motor.
(4) The oil line is blocked
If the orifice of the balancing valve in the one-sided parking brake oil path is blocked by foreign objects, the pressure oil cannot enter the balancing valve through the orifice to push its spool to move, resulting in the parking brake cannot be released and the walking motor cannot rotate 3. The excavator has a walking and running failure.
If the throttling oil passage of the excavator's brake is blocked by a foreign body, it may also cause the parking brake to not be released, causing the walking motor to fail to rotate, and the excavator to have a running deviation failure. The throttle oil passage for releasing the brake is shown in Figure 4 As shown.
The repair method is as follows: after exchanging the four high-pressure hoses connected to the central rotary joint of the excavator and the walking motor, test the machine. If the failure phenomenon remains unchanged, it can be determined that the walking deceleration mechanism or the walking motor is faulty. After swapping the safety relief valves of the left and right running motors and testing the machine, if the fault phenomenon remains unchanged, it may be the balance valve or the brake oil circuit is blocked. The balance valve needs to be cleaned or the brake oil circuit is removed. Avoid foreign matter entering the oil circuit, and replace the hydraulic oil and filter element.
(5) Walking pilot valve
The walking pilot valve can output corresponding pressure oil according to the stroke of the joystick, so that the main control valve produces a corresponding amount of movement, thereby controlling the walking speed of the excavator. If the output oil pressure of the pilot valve on both sides is inconsistent, or the spool of the pilot valve on one side is stuck by foreign objects, it can cause the excavator to run away.
The maintenance method is as follows: measure the hydraulic pressure of the travel pilot valve. If the output oil pressure of the travel pilot valve on both sides is inconsistent, it can be determined that the travel pilot valve is faulty; disassemble and clean the pilot valve and related oil circuit, and replace the hydraulic oil and filter element.
In addition, if the excavator on the left and right sides of the track tension is not consistent, it can also cause excavator walking deviation. If the tension of the tracks on both sides is inconsistent, add grease to the slack track tensioner to make it consistent with the tension on the other side.
