Use hydraulic oil gauge to accurately diagnose the fault of excavator hydraulic system
Posted: Mar 26th, '25, 04:26
In the daily operation of excavators, the hydraulic system is like its "power heart" to ensure the efficient and stable operation of various actions. As an intuitive "monitor" of the state of the hydraulic system, the hydraulic oil gauge plays a key role in discovering and diagnosing system faults in time. Through the accurate interpretation of the hydraulic fuel gauge data, maintenance personnel can quickly locate the fault point, develop effective maintenance strategies, reduce equipment downtime, and improve work efficiency. This paper will discuss in detail how to use hydraulic oil gauge to diagnose the fault of excavator hydraulic system, and help the majority of machine owners and maintenance personnel to master this practical skill.
Hydraulic gauge Basics: Understand key data
The excavator hydraulic system is usually equipped with multiple hydraulic oil gauges to monitor the pressure, flow and other parameters of different parts. Among them, the main pressure oil gauge reflects the pressure value of the main oil circuit of the system, which is an important basis for judging the working status of key components such as hydraulic pump and relief valve. Under normal circumstances, the main pressure value of different types of excavators will be clearly marked in the product manual, generally between 20-40MPa. For example, the standard value of the main pressure of a common type of excavator is 32MPa, and when the hydraulic oil gauge displays a value that deviates from this range, it may indicate that there is a fault in the system.
The flow gauge is used to monitor the flow rate and flow of hydraulic oil in the pipeline, and its value change can reflect the output capacity of the hydraulic pump and whether there is a blockage in the pipeline. In addition, there is a pilot pressure gauge for monitoring the pilot oil line pressure, the pilot system is responsible for controlling the action of the main oil line reversing valve, the abnormal pilot pressure will directly lead to operation failure, the normal pilot pressure is generally about 2-5MPa.
Abnormal pressure diagnosis: Identify potential causes of failure
Low pressure
When the hydraulic oil gauge shows that the main pressure is too low, it may be caused by a number of reasons. First of all, hydraulic pump failure is one of the common factors. Hydraulic pump internal parts wear, such as the plunger, valve plate, etc., will lead to a decrease in the volume efficiency of the pump, the output pressure is insufficient. At this time, you can check by disassembling the hydraulic pump, observe the wear of the parts, and replace the severely worn parts if necessary.
Secondly, the failure of the relief valve will also cause the pressure to be too low. The function of the relief valve is to overflow excess oil back to the tank to protect the system when the system pressure exceeds the set value. If the spool of the relief valve is stuck in the open position, or the spring fatigue fails, the system pressure cannot be established. During maintenance, the relief valve can be cleaned, adjusted or replaced by the spring to restore its normal working performance.
In addition, insufficient hydraulic oil, pipeline leakage, etc., will also lead to pressure drop. Check the oil level of the hydraulic tank to ensure sufficient oil; At the same time, carefully check the connection parts of the pipeline to see whether there is oil leakage, and repair the leak point in time. For example, the main pressure oil gauge of an excavator at a certain construction site shows only 18MPa. After inspection, it is found that a joint of the hydraulic oil pipeline is loose. After fastening the joint and replenishment of hydraulic oil, the pressure returns to normal.
overpressure
The hydraulic oil gauge shows that the pressure is too high. This may be due to a blockage in a part of the system, such as a clogged filter, resulting in poor oil flow and elevated pressure buildup. Regular replacement of the filter is an effective measure to prevent such failures. In addition, when one of the reversing valve spool in the system is stuck in the closed position, the oil cannot circulate normally, and the pressure is too high. At this time, it is necessary to disassemble and clean the reversing valve to ensure the flexible movement of the spool. If the pressure continues to be too high, it may also cause damage to the system seals, oil pipes, etc., leading to more serious failures.
Troubleshooting Traffic anomalies: Insight into the system running status
Abnormal flow gauge values often reflect problems with hydraulic pumps or pipelines. When the flow rate is too low, it may be that the internal wear of the hydraulic pump is serious, resulting in a reduction in the output flow rate; It may also be that there is a foreign body blocked in the pipeline, restricting the flow of oil. For hydraulic pump wear, it is necessary to repair or replace in time; For pipeline blockage, the method of flushing the pipeline can be used to eliminate the fault. On the contrary, if the flow rate is too high, it may be that there is leakage in the system, and some oil is directly reflow without the executing element, at this time, it should be checked whether the seal is damaged and whether the pipeline is damaged.
Comprehensive diagnosis: multi-parameter collaborative analysis
In the actual fault diagnosis, it can not only rely on the data of a single hydraulic oil gauge, but need to synthesize several oil gauge parameters for analysis. For example, when the main pressure is normal but the flow is abnormal, the fault may be concentrated in the line or the actuator; If the main pressure and pilot pressure are abnormal at the same time, it may be a problem with core components such as hydraulic pumps or relief valves. Through multi-parameter collaborative analysis, the fault point can be locked more accurately and the diagnosis efficiency can be improved.
Regular maintenance and monitoring: prevent failures
In order to give full play to the role of hydraulic oil gauge in fault diagnosis, it is very important to maintain and monitor the hydraulic system regularly. Regularly check the cleanliness and oil level of hydraulic oil, and replace hydraulic oil and filter as required; Before each operation, observe the initial value of the hydraulic oil gauge, record the data changes during the operation process, and establish the operation file of the equipment. Through long-term data accumulation and analysis, the potential problems of the system can be discovered in advance, and timely preventive measures can be taken to avoid the impact of sudden failures on the construction schedule.
In short, mastering the method of using hydraulic oil gauge to diagnose the fault of excavator hydraulic system is the key to ensure the stable operation of excavator and extend the service life of equipment. Both the owner and the maintenance personnel should pay attention to the hydraulic oil gauge as an important tool, constantly improve the fault diagnosis ability, and escort the efficient operation of the excavator.
Hydraulic gauge Basics: Understand key data
The excavator hydraulic system is usually equipped with multiple hydraulic oil gauges to monitor the pressure, flow and other parameters of different parts. Among them, the main pressure oil gauge reflects the pressure value of the main oil circuit of the system, which is an important basis for judging the working status of key components such as hydraulic pump and relief valve. Under normal circumstances, the main pressure value of different types of excavators will be clearly marked in the product manual, generally between 20-40MPa. For example, the standard value of the main pressure of a common type of excavator is 32MPa, and when the hydraulic oil gauge displays a value that deviates from this range, it may indicate that there is a fault in the system.
The flow gauge is used to monitor the flow rate and flow of hydraulic oil in the pipeline, and its value change can reflect the output capacity of the hydraulic pump and whether there is a blockage in the pipeline. In addition, there is a pilot pressure gauge for monitoring the pilot oil line pressure, the pilot system is responsible for controlling the action of the main oil line reversing valve, the abnormal pilot pressure will directly lead to operation failure, the normal pilot pressure is generally about 2-5MPa.
Abnormal pressure diagnosis: Identify potential causes of failure
Low pressure
When the hydraulic oil gauge shows that the main pressure is too low, it may be caused by a number of reasons. First of all, hydraulic pump failure is one of the common factors. Hydraulic pump internal parts wear, such as the plunger, valve plate, etc., will lead to a decrease in the volume efficiency of the pump, the output pressure is insufficient. At this time, you can check by disassembling the hydraulic pump, observe the wear of the parts, and replace the severely worn parts if necessary.
Secondly, the failure of the relief valve will also cause the pressure to be too low. The function of the relief valve is to overflow excess oil back to the tank to protect the system when the system pressure exceeds the set value. If the spool of the relief valve is stuck in the open position, or the spring fatigue fails, the system pressure cannot be established. During maintenance, the relief valve can be cleaned, adjusted or replaced by the spring to restore its normal working performance.
In addition, insufficient hydraulic oil, pipeline leakage, etc., will also lead to pressure drop. Check the oil level of the hydraulic tank to ensure sufficient oil; At the same time, carefully check the connection parts of the pipeline to see whether there is oil leakage, and repair the leak point in time. For example, the main pressure oil gauge of an excavator at a certain construction site shows only 18MPa. After inspection, it is found that a joint of the hydraulic oil pipeline is loose. After fastening the joint and replenishment of hydraulic oil, the pressure returns to normal.
overpressure
The hydraulic oil gauge shows that the pressure is too high. This may be due to a blockage in a part of the system, such as a clogged filter, resulting in poor oil flow and elevated pressure buildup. Regular replacement of the filter is an effective measure to prevent such failures. In addition, when one of the reversing valve spool in the system is stuck in the closed position, the oil cannot circulate normally, and the pressure is too high. At this time, it is necessary to disassemble and clean the reversing valve to ensure the flexible movement of the spool. If the pressure continues to be too high, it may also cause damage to the system seals, oil pipes, etc., leading to more serious failures.
Troubleshooting Traffic anomalies: Insight into the system running status
Abnormal flow gauge values often reflect problems with hydraulic pumps or pipelines. When the flow rate is too low, it may be that the internal wear of the hydraulic pump is serious, resulting in a reduction in the output flow rate; It may also be that there is a foreign body blocked in the pipeline, restricting the flow of oil. For hydraulic pump wear, it is necessary to repair or replace in time; For pipeline blockage, the method of flushing the pipeline can be used to eliminate the fault. On the contrary, if the flow rate is too high, it may be that there is leakage in the system, and some oil is directly reflow without the executing element, at this time, it should be checked whether the seal is damaged and whether the pipeline is damaged.
Comprehensive diagnosis: multi-parameter collaborative analysis
In the actual fault diagnosis, it can not only rely on the data of a single hydraulic oil gauge, but need to synthesize several oil gauge parameters for analysis. For example, when the main pressure is normal but the flow is abnormal, the fault may be concentrated in the line or the actuator; If the main pressure and pilot pressure are abnormal at the same time, it may be a problem with core components such as hydraulic pumps or relief valves. Through multi-parameter collaborative analysis, the fault point can be locked more accurately and the diagnosis efficiency can be improved.
Regular maintenance and monitoring: prevent failures
In order to give full play to the role of hydraulic oil gauge in fault diagnosis, it is very important to maintain and monitor the hydraulic system regularly. Regularly check the cleanliness and oil level of hydraulic oil, and replace hydraulic oil and filter as required; Before each operation, observe the initial value of the hydraulic oil gauge, record the data changes during the operation process, and establish the operation file of the equipment. Through long-term data accumulation and analysis, the potential problems of the system can be discovered in advance, and timely preventive measures can be taken to avoid the impact of sudden failures on the construction schedule.
In short, mastering the method of using hydraulic oil gauge to diagnose the fault of excavator hydraulic system is the key to ensure the stable operation of excavator and extend the service life of equipment. Both the owner and the maintenance personnel should pay attention to the hydraulic oil gauge as an important tool, constantly improve the fault diagnosis ability, and escort the efficient operation of the excavator.