1 Dirt enters the balance valve in the parking brake oil path on the side of the loader. If the loader is running, if there is dirt blocking the small hole of the balance valve, the parking brake cannot be exempted, and then the walking deviation is caused. This is because when the loader is walking, if the pressure oil cannot enter the tension spring chamber of the balance valve through the small hole of the balance valve to advance the movement of the balance valve spool, 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 there will be 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. ,
2 Dirt blocks the small hole K of the balance valve of the final drive system, resulting in the parking brake cannot be waived
When walking in the loader, if the pressure oil cannot pass through the small hole K on the balance valve to promote the movement of the balance valve spool, the pressure oil cannot pass through the groove on the balance valve to avoid parking power, resulting in the walking motor not rotating normally. Cause the loader to run away. Sweeping method: clean the oil circuit, and pay attention to avoid the entry of dirty things when disassembling in the future, and replace the hydraulic oil and filter element on time,
3 The center reverse joint sealing ring is damaged
The center reversing 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. The mandrel has an annular groove equal to the oil pipe. The hydraulic oil from the main valve core flows through the housing from the vertical hole on the mandrel to the motor. The housing is continuously reversed with the upper body, and the groove on the mandrel can also be kept clear of the oil port on the housing. Hydraulic oil can freely enter and exit on the center joint.
If the filter element of the hydraulic oil is not replaced in time, the bypass valve on the filter element may be opened, and the impurities in the oil directly enter the sliding surface of the center reversing joint without filtering, and the sealing ring on the filter is damaged. The loader The speed of the motors on both sides is not the same due to the leakage of pressure oil from one side during internal walking, which results in the deviation of the loader during walking. The cleaning method is: when replacing the oil on the center reversing joint, replace the hydraulic oil and the filter element together.
4 Leakage of the travel motor safety valve Leakage of the travel motor safety valve will cause the pressure in the system to be too low to allow the travel motor to rotate insufficiently, and then the travel deviation cleaning method will appear: Replace the travel motor safety valve that has been damaged. 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.
5 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 motor is subjected to a huge impact from the outside, the abnormal high pressure in the hydraulic cylinder or motor can be removed, and then the related oil pipes and cylinders are protected from damage. If the walking suction valve is damaged and the spring in the valve is soft or broken, the walking main valve
The oil pressure inside will drop, resulting in insufficient driving force of the walking motor and causing deviation. Sweeping method: repair or replace the suction valve. ,
6 The spool of the walking main valve deflecting from the loader 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. When checking, measure the pressure of the walking main valve oil circuit. The normal value is 30.5MPa. If the walking main valve is damaged, it needs to be replaced or repaired. We have encountered the Daewoo DH220LC-V loader walking deviation. The result is the walking main valve. Caused by the damaged ring, when a walking deviation error occurs, the first consideration should be whether the walking main spool has been damaged.
7 The degree of tension of the crawler is different from left to right. If the loader is walking, the tension of the crawler on the left and right sides is not the same, and it will also make the walking deviation. Sweep out the fault: Fill the loose side with butter to make it as tight as the other side,
8 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, it may cause the filter element to block and open the oil filter bypass valve. The dirty hydraulic oil directly enters the circuit of the proportional valve without filtering, resulting in the spool valve being blocked. If it is stuck, the control oil can not flow to the reverse main control valve through the reverse proportional valve on the deflection side of the loader, which causes the walk to deviate. At this time, check the pressure of the walking proportional valve (3.3MPa). Sweeping method: clean the valve body and phase front oil circuit, replace hydraulic oil and filter element.
Summary: During operation, the loader must select qualified hydraulic oil according to the instructions, pay attention to maintaining the cleanliness of the hydraulic oil to avoid contamination during oil change; together, the hydraulic oil and filter element should be replaced in accordance with the regulations in time, as long as this is the only way to ensure loading The machine has fewer failures, extending its service life.
