Due to maintenance or operation reasons, many users have problems with walking deviation when loading. If we encounter deviations in the loader during operation, how to find the cause and remove it?
1 The center reverse joint sealing ring is damaged. The center reverse joint is composed of two parts: the shell and the mandrel. The mandrel equipment is on the lower body, and the shell equipment is on the upper body. Ring groove. The hydraulic oil from the main valve core flows from the straight hole on the mandrel to the motor through the housing. The housing is continuously reversed with the upper body, and the groove on the mandrel can also keep the oil port on the housing open. Hydraulic oil can freely enter and exit on the center joint. If the filter element of the hydraulic oil is not replaced in time, it may cause the bypass valve on the filter element to open, and the impurities in the oil will directly enter the sliding surface of the center reversing joint without being filtered, and the sealing ring on the filter element will be damaged. When running in the machine, the speed of the two sides of the motor is not the same due to the leakage of pressure oil on one side, resulting in a deviation of the loader's walking. The cleaning method is: when replacing the oil on the center reverse joint, replace the hydraulic oil and the filter element together.
2 Dirt enters the balance valve in the parking brake oil path on the side of the loader If the loader is walking, if there is dirt blocking the small hole of the balance valve, the parking brake cannot be waived, and then the walking deviation is formed. This is because when the loader is walking, if the pressure oil cannot enter the spring chamber of the balance valve through the small hole of the balance valve to push the balance valve spool to move, the pressure oil cannot enter the hydraulic system through the groove on the balance valve , Resulting in the parking brake force cannot be exempted, as a result, the walking motor cannot rotate, so it will also show walking deviation. Sweeping method: remove the balance valve and clean it. When disassembling, no dirt can enter; regularly replace the hydraulic oil and filter element that meet the requirements.
3 Leakage of the safety valve of the travel motor The leakage of the safety valve of the travel motor will cause the pressure in the system to be too low and the rotation of the travel motor will not be enough, and then it will show a deviation in walking.
Sweeping method: replace the damaged safety valve of the walking motor. When judging, the safety valves of the left and right walking motors can be swapped to see if they are deflected when walking in the reverse direction.
4 Dirt blocks the small hole K of the balance valve of the final drive system, resulting in parking brakes that are not exempt from walking in the loader. If the pressure oil cannot pass through the small hole K on the balance valve to move the balance valve spool, the pressure The oil can not pass through the groove on the balance valve to avoid the parking power, which causes the walking motor to not rotate normally and form the deflection of the loader. Sweeping method: clean the oil circuit, and pay attention to avoid the entry of dirty things when disassembling backwards, and replace the hydraulic oil and filter element on time.
5 The spool of the walking main valve with the loader deflecting fails to function. If the tension spring in the walking main valve becomes soft or broken, or the spool is stuck, it may cause a drop in oil pressure and a walking deviation. During the inspection, the pressure of the oil path of the walking main valve should be measured. The normal value is 30.5MPa. If the walking main valve is damaged, it needs to be replaced or repaired. Damaged ring caused, when showing the deviation of walking and running, should first consider whether the walking main spool has been damaged. 6 The walking suction valve on the deflection side of the loader is damaged. The suction valve is installed on the hydraulic cylinder and motor of the work equipment. Its function is: when the hydraulic cylinder or the motor is impacted by the outside world, it can remove the abnormal high pressure in the hydraulic cylinder or the motor, and then maintain the related oil pipes and cylinders from damage. If the walking suction valve is damaged and the tension spring in the valve is soft or broken, the oil pressure in the walking main valve will drop, resulting in insufficient driving force of the walking motor and causing deviation. Sweeping method: repair or replace the suction valve.
7 The degree of tension of the crawler is different from left to right. Eliminate the problem: Fill the loose side with butter to make it tighter than the other side.
8 The performance of the oil pump is reduced. When the loader runs straight, the plunger of one of the pump's pump flow regulators is stuck in a certain direction, or because of serious wear, internal leakage, and the system pressure can only reach 29.5MPa, so the walking motor The speed becomes slower and the timing of loading is deviated. Cleaning method: Remove the hydraulic pump assembly from the loader, replace the worn parts, repair the regulator, and replace the hydraulic oil and filter element.
The output pressure of the travel proportional valve on the deflecting side of the loader is too low. The proportional valve can output the corresponding control oil pressure according to the length of the control handle control stroke, so that the main control valve has a corresponding amount of movement, and then control the speed of the work equipment. If the filter element of the oil filter is not changed on time, the filter element may be blocked, causing the bypass valve of the oil filter to open, and the dirty hydraulic oil directly enters the circuit of the proportional valve without filtering, resulting in a spool in the valve If it is stuck, the control oil cannot flow to the reverse main control valve through the reverse proportional valve on the deflecting side of the loader, resulting in walking deviation. Check the pressure of the walking proportional valve (3.3MPa) at this moment. Sweeping method: clean the valve body and the oil path before the phase, and replace the hydraulic oil and filter element. Summary: The loader must use qualified hydraulic oil in accordance with the instructions in the operation, pay attention to maintaining the cleanliness of the hydraulic oil to prevent contamination during oil change; together, the hydraulic oil and the filter element should be replaced in accordance with the regulations in time, and only then can the loading be ensured The machine has fewer problems and extends its service life.
