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Excavator travel motor maintenance and use
2022-04-29
Precautions for the use of excavators
1. Whether it is a big dig or a small dig, try to walk as short as possible. Long-term walking distance will damage the walking wheels of the excavator; try to make way for a flat road when walking through, especially when walking on an uphill road with a slow speed. You must use a slow gear, and if necessary, use a hook to cooperate. Don't let the walking have too much compounding, which is very harmful to walking.
2. The planetary gearbox must be filled with gear oil. After the initial use, the gear oil should be replaced every three months, and then the gear oil should be replaced every 1 year according to different working conditions. After the travel motor has been running for a period of time, the rear cover of the gearbox should be removed, and the wear of the gearbox should be checked regularly for timely maintenance.
3. During the operation of the walking motor, the working condition of the system oil circuit and the motor gear oil should be checked frequently. If the system pressure is abnormally increased, the walking motor leaks, the abnormal temperature rises, the vibration noise or the abnormal pressure pulsation is found, it should be stopped immediately. Find out the cause and repair it in time.
4. When the traveling motor of the excavator is weak or the system is abnormal, it should be stopped immediately to check whether the leakage of the hydraulic motor is normal. If there is a large amount of leakage, the hydraulic motor is damaged and needs to be repaired or replaced.
5. It is recommended to stop for about 15 minutes after the excavator travel motor works continuously for 1-2 hours.
6. Set a safety valve in the circuit that drives the traveling motor. If the hydraulic motor is a radial piston motor, the set value of its overflow pressure should not exceed 22MPa, and if the hydraulic motor is a cycloid hydraulic motor, its overflow pressure should not exceed 17MPa. The set pressure of the motor relief valve can reach about 35Mpa according to the requirements of the host equipment.
7. The neutral function of the steering control reversing valve of the walking hydraulic circuit must be "Y" type or "H" type.
8. If the hydraulic oil is too dirty, it will affect the service life of the excavator travel motor.
Causes of slow walking and how to fix it
1. The sealing ring of the central rotary joint is damaged
The central rotary joint is composed of two parts, the shell and the mandrel. The mandrel is installed on the lower body, the shell is installed on the upper body, and the mandrel is provided with an annular groove equal to the oil pipe. The hydraulic oil from the main spool flows from the vertical hole on the mandrel to the motor through the casing, the casing rotates continuously with the upper body, the groove on the mandrel can also keep the oil port on the casing unobstructed, Oil can enter and exit freely on the center fitting. 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 will directly enter the sliding surface of the central rotary joint without filtering the hydraulic oil, which will damage the sealing ring on the excavator. When walking, the speed of the walking motors on both sides is different due to the leakage of the pressure oil on one side, and the result is that the excavator deviates. The elimination method is: when replacing the oil on the center rotary joint, replace the hydraulic oil and the filter element of the excavator accessories at the same time.
2. Dirt enters the balance valve in the parking brake oil circuit on the side of the excavator
When the excavator is walking, if there is dirt blocking the small hole of the balance valve, the parking brake cannot be released, resulting in a deviation of the walking. This is because the pressure oil cannot enter through the small hole of the balance valve when the excavator is walking. If the spring chamber of the balance valve pushes the balance valve spool to move, the pressure oil cannot enter its hydraulic system through the groove on the balance valve, so that the parking braking force cannot be released, and as a result, the walking motor cannot rotate, so the walking deviation will also occur. . Remedy: remove the balance valve and clean it. During disassembly, no dirt can enter; regularly replace the hydraulic oil and filter element that meet the requirements.
3. Oil leakage from the safety valve of the walking motor
The oil leakage of the safety valve of the walking motor will cause the pressure in the system to be too low and the rotation of the walking motor will not be enough, resulting in the walking deviation. Remedy: replace the damaged safety valve of the walking motor. When judging, the safety valve of the left and right travel motors can be exchanged to see if they are deflected when traveling in the opposite direction.
4. Dirt blocks the small hole of the balance valve of the final drive system, causing the parking brake to not be released
When the excavator is walking, if the pressure oil cannot push the balance valve spool to move through the small hole on the balance valve, the pressure oil cannot pass through the groove on the balance valve to release the parking power, so that the walking motor cannot rotate normally, resulting in excavation. The machine walks off track. Remedy: clean the oil circuit, and pay attention to avoid the entry of dirty things when disassembling and assembling in the future, and replace the hydraulic oil and filter element on time.
5. The movement of the main valve spool of the excavator deflected
If the spring in the main travel valve becomes soft or broken, or the spool is stuck, it may cause the oil pressure to drop and travel deviation. During inspection, the pressure of the oil circuit of the main travel valve should be measured. The normal value is 30.5MPa. If the main travel valve is damaged, it needs to be replaced or repaired. We have encountered the Daewoo DH220LC-V excavator walking deviation, and the inspection result is that the main travel valve Caused by the damaged ring, when the running deviation fault occurs, it should first consider whether the running main spool is damaged.
6. The walking oil suction valve on the deflection side of the excavator is damaged
The oil suction valve is installed on the hydraulic cylinder and motor of the working device. Its function is: when the hydraulic cylinder or motor is greatly impacted by the outside world, the abnormal high pressure in the hydraulic cylinder or motor can be removed, thereby protecting the relevant oil pipes and cylinders from damage. If the travel oil suction valve is damaged and the spring in the valve is soft or broken, the oil pressure in the travel main valve will decrease, resulting in insufficient driving force of the travel motor and causing deviation. Remedy: Repair or replace the suction valve.
7. The degree of tension of the crawler varies from left to right
If the excavator is walking, the crawler on the left and right sides has different tightening degrees, which will also cause the excavator to deviate when walking. Troubleshooting: Butter the loose side to make it the same tightness as the other side.
8. The performance of the large pump decreases
1. Whether it is a big dig or a small dig, try to walk as short as possible. Long-term walking distance will damage the walking wheels of the excavator; try to make way for a flat road when walking through, especially when walking on an uphill road with a slow speed. You must use a slow gear, and if necessary, use a hook to cooperate. Don't let the walking have too much compounding, which is very harmful to walking.
2. The planetary gearbox must be filled with gear oil. After the initial use, the gear oil should be replaced every three months, and then the gear oil should be replaced every 1 year according to different working conditions. After the travel motor has been running for a period of time, the rear cover of the gearbox should be removed, and the wear of the gearbox should be checked regularly for timely maintenance.
3. During the operation of the walking motor, the working condition of the system oil circuit and the motor gear oil should be checked frequently. If the system pressure is abnormally increased, the walking motor leaks, the abnormal temperature rises, the vibration noise or the abnormal pressure pulsation is found, it should be stopped immediately. Find out the cause and repair it in time.
4. When the traveling motor of the excavator is weak or the system is abnormal, it should be stopped immediately to check whether the leakage of the hydraulic motor is normal. If there is a large amount of leakage, the hydraulic motor is damaged and needs to be repaired or replaced.
5. It is recommended to stop for about 15 minutes after the excavator travel motor works continuously for 1-2 hours.
6. Set a safety valve in the circuit that drives the traveling motor. If the hydraulic motor is a radial piston motor, the set value of its overflow pressure should not exceed 22MPa, and if the hydraulic motor is a cycloid hydraulic motor, its overflow pressure should not exceed 17MPa. The set pressure of the motor relief valve can reach about 35Mpa according to the requirements of the host equipment.
7. The neutral function of the steering control reversing valve of the walking hydraulic circuit must be "Y" type or "H" type.
8. If the hydraulic oil is too dirty, it will affect the service life of the excavator travel motor.
Causes of slow walking and how to fix it
1. The sealing ring of the central rotary joint is damaged
The central rotary joint is composed of two parts, the shell and the mandrel. The mandrel is installed on the lower body, the shell is installed on the upper body, and the mandrel is provided with an annular groove equal to the oil pipe. The hydraulic oil from the main spool flows from the vertical hole on the mandrel to the motor through the casing, the casing rotates continuously with the upper body, the groove on the mandrel can also keep the oil port on the casing unobstructed, Oil can enter and exit freely on the center fitting. 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 will directly enter the sliding surface of the central rotary joint without filtering the hydraulic oil, which will damage the sealing ring on the excavator. When walking, the speed of the walking motors on both sides is different due to the leakage of the pressure oil on one side, and the result is that the excavator deviates. The elimination method is: when replacing the oil on the center rotary joint, replace the hydraulic oil and the filter element of the excavator accessories at the same time.
2. Dirt enters the balance valve in the parking brake oil circuit on the side of the excavator
When the excavator is walking, if there is dirt blocking the small hole of the balance valve, the parking brake cannot be released, resulting in a deviation of the walking. This is because the pressure oil cannot enter through the small hole of the balance valve when the excavator is walking. If the spring chamber of the balance valve pushes the balance valve spool to move, the pressure oil cannot enter its hydraulic system through the groove on the balance valve, so that the parking braking force cannot be released, and as a result, the walking motor cannot rotate, so the walking deviation will also occur. . Remedy: remove the balance valve and clean it. During disassembly, no dirt can enter; regularly replace the hydraulic oil and filter element that meet the requirements.
3. Oil leakage from the safety valve of the walking motor
The oil leakage of the safety valve of the walking motor will cause the pressure in the system to be too low and the rotation of the walking motor will not be enough, resulting in the walking deviation. Remedy: replace the damaged safety valve of the walking motor. When judging, the safety valve of the left and right travel motors can be exchanged to see if they are deflected when traveling in the opposite direction.
4. Dirt blocks the small hole of the balance valve of the final drive system, causing the parking brake to not be released
When the excavator is walking, if the pressure oil cannot push the balance valve spool to move through the small hole on the balance valve, the pressure oil cannot pass through the groove on the balance valve to release the parking power, so that the walking motor cannot rotate normally, resulting in excavation. The machine walks off track. Remedy: clean the oil circuit, and pay attention to avoid the entry of dirty things when disassembling and assembling in the future, and replace the hydraulic oil and filter element on time.
5. The movement of the main valve spool of the excavator deflected
If the spring in the main travel valve becomes soft or broken, or the spool is stuck, it may cause the oil pressure to drop and travel deviation. During inspection, the pressure of the oil circuit of the main travel valve should be measured. The normal value is 30.5MPa. If the main travel valve is damaged, it needs to be replaced or repaired. We have encountered the Daewoo DH220LC-V excavator walking deviation, and the inspection result is that the main travel valve Caused by the damaged ring, when the running deviation fault occurs, it should first consider whether the running main spool is damaged.
6. The walking oil suction valve on the deflection side of the excavator is damaged
The oil suction valve is installed on the hydraulic cylinder and motor of the working device. Its function is: when the hydraulic cylinder or motor is greatly impacted by the outside world, the abnormal high pressure in the hydraulic cylinder or motor can be removed, thereby protecting the relevant oil pipes and cylinders from damage. If the travel oil suction valve is damaged and the spring in the valve is soft or broken, the oil pressure in the travel main valve will decrease, resulting in insufficient driving force of the travel motor and causing deviation. Remedy: Repair or replace the suction valve.
7. The degree of tension of the crawler varies from left to right
If the excavator is walking, the crawler on the left and right sides has different tightening degrees, which will also cause the excavator to deviate when walking. Troubleshooting: Butter the loose side to make it the same tightness as the other side.
8. The performance of the large pump decreases
When the excavator walks straight, the plunger of the pump flow regulator of one of the pumps is stuck in a certain position, or due to serious wear, internal leakage, and the system pressure can only reach 29.5MPa, the speed of the travel motor is slowed down. , the excavator may deviate. Remedy: Remove the hydraulic pump assembly from the excavator, replace the worn parts, repair the regulator, and replace the hydraulic oil and filter element.
