There are 9 kinds of reasons, all of which can cause the excavator to run off course

July 6, 2021
Latest company news about There are 9 kinds of reasons, all of which can cause the excavator to run off course

Due to maintenance or operation reasons, many users' excavators will have the fault of walking deviation. If we encounter the phenomenon of running deviation in the work of excavators, how to find the cause and eliminate it?

1. The sealing ring of the central rotary joint is damaged

The central rotary joint is composed of a shell and a mandrel. The mandrel is installed on the lower body, and the shell is installed on the upper body. The mandrel is provided with an annular groove equal to the tubing. The hydraulic oil from the main valve core flows to the motor from the vertical hole on the core shaft through the shell, and the shell continues to turn with the upper body. The groove on the core shaft can also keep the oil opening on the shell smooth, and the hydraulic oil can freely enter and exit on the central joint. If not timely replacement of hydraulic oil filter, could lead to filter on the bypass valve opens, the hydraulic oil without filter makes the impurity in the oil directly into the center of the swivel joint sliding on the surface, make its sealing ring damage, videotapes excavator caused by the pressure oil leakage on one side of the walk on both sides of the motor speed is different, the result is to avoid wandering. The elimination method is to replace the oil on the central rotary joint, and replace the hydraulic oil and filter element at the same time.


2. Dirt enters the balance valve in the parking brake oil road on the side of the excavator

Walking excavator if there is dirt blocked the balance valve holes, lead to parking brake cannot be lifted, resulting in walking running deviation, this is because the videotapes excavator, pressure oil if not through balancing valve holes into the balance valve spring chamber to promote balanced valve core is moving, the pressure oil can't through the groove of the balancing valve into the hydraulic system, As a result, the stopping brake force cannot be lifted, and the walking motor cannot rotate, so there will be walking deviation. Elimination method: remove the balance valve and clean, in the disassembly, no dirt into; Replace the hydraulic oil and filter element that meet the requirements regularly.


3, walking motor safety valve oil leakage

The leakage of the safety valve of the walking motor will lead to the low pressure in the system so that the rotation of the walking motor is not enough, resulting in the running deviation. Elimination method: replace the damaged walking motor safety valve. When judging, the safety valve of the left and right walking motors can be changed to see whether the reverse walking is deflected.


4. Dirt blocks the small hole K of the balance valve of the final transmission system, resulting in the parking brake cannot be lifted

When the excavator is walking, if the pressure oil can not push the balance valve spool to move through the hole K on the balance valve, the pressure oil can not lift the parking power through the groove on the balance valve, leading to the normal rotation of the walking motor, resulting in the excavator walking deviation. Elimination method: clean the oil road, and pay attention to the future disassembly to avoid dirty things into, and to replace the hydraulic oil and filter element on time.


5. The spool of the main valve of excavator deflection fails

If the spring in the main valve becomes soft or broken, or the spool is stuck, it may cause the oil pressure to decrease and the running deviation may occur. When checking, the pressure of the oil road of the main valve should be measured, and the normal value is 30.5MPa. If the main valve is damaged, it should be replaced or repaired. We once encountered Daewoo DH220LC-V excavator walking off track, and the inspection result is caused by the damage ring of the main valve.


6. The walking oil suction valve on the deflection side of the excavator is damaged

The suction valve is mounted on the hydraulic cylinder and motor of the working device. Its function is: when the hydraulic cylinder or the horse by the outside huge impact, can remove the abnormal high pressure in the hydraulic cylinder or the motor, so as to protect the relevant tubing and cylinder from damage. If the walking oil suction valve is damaged and the spring in the valve is soft or broken, the oil pressure in the walking main valve will be reduced, leading to the insufficient driving force of the walking motor and causing the deviation. Elimination method: repair or replace the suction valve.


7. The tightness degree of caterpillar is different

If the excavator is walking, the tightness of the tracks on the left and right sides is not the same, it will also make the running deviation when walking. Troubleshooting: Add butter to the loose side to make it as tight as the other side.


8. The performance of oil pump decreases

When the excavator walks in a straight line, the plunger of the pump flow regulator of one of the pumps is stuck in a certain position, or because of serious wear, internal leakage, system pressure can only reach 29.5mpa, so that the speed of the walking motor is slow, and the excavator will run off. Elimination method: remove the hydraulic pump assembly from the excavator, replace the worn parts, repair the regulator, and replace the hydraulic oil and filter element.


9. The output pressure of the walking proportional valve on the deflection side of the excavator is too low

The proportional valve can output the corresponding control oil pressure according to the length of the operation handle to control the stroke, so that the main control valve has the corresponding amount of movement, so as to control the speed of the working device. If unable to change the filter cartridge, on time may lead to blockages in the filter element, make the oil filter bypass valve is opened, the dirty hydraulic oil in the case of unfiltered directly into the proportional valve circuit, lead to the slide valve is stuck inside the valve, control oil cannot be the excavator deflection rotary proportional valve to turn on one side of the main control valve, wandering in walking. At this point, check the pressure of the proportional valve (3.3mpa).

Elimination method: clean the valve body and the oil circuit before the phase, replace the hydraulic oil and filter element.


The excavator must choose qualified hydraulic oil according to the requirements of the manual in use, pay attention to keep the cleanliness of hydraulic oil, prevent pollution when changing oil; At the same time, the hydraulic oil and filter element should be replaced in time according to the provisions, only in this way to ensure less failure of the excavator, prolong its service life.