How To Identify Some Common Problems And Problems Of Hydraulic Excavator?
The primary way to troubleshoot the system of large hydraulic excavators is still the diagnosis method. Maintenance personnel use the theoretical knowledge and accumulated experience, combined with the practice of the machine, quickly diagnose the fault location and cause of a way.
1. Listen
"Listen" is to use the ear to check the hydraulic system for abnormal sounds. Normal machine operation has a certain rhythm and rhythm, and maintain stability. Therefore, understand and grasp these rules, and maintain stability. Therefore, understanding and grasping these rules can accurately diagnose whether the hydraulic system is working normally; Together, according to the change of rhythm and rhythm, as well as the parts of abnormal sound, the parts of the fault can be determined, and the parts of the fault can be determined and the degree of damage.
A high-pitched, high-pitched whistle, usually inhaled air; Hydraulic pump "chirp" or "cluck" sound, often pump shaft or bearing damage; The reversing valve announces the sound of "wheezing", which is the lack of stem opening; The heavy "tap" sound may be the sound of overload valve. If it is cavitation sound, it may be that the oil filter is blocked by dirt, the hydraulic pump suction pipe is loose, or the oil tank level is too low.
Second look
"Look" is to see the working condition of the hydraulic system through the eyes. Such as whether the amount of oil in the tank meets the requirements, there is no bubble and discoloration phenomenon (machine noise, oscillation and creeping are often related to many bubbles in the oil); The oil leakage situation at the sealing part and the pipe street number; Pressure gauge and oil temperature gauge in the operation of the indicated value change; There is no damage to the fault parts, gradual falling off of the connection and loosening of the fixed parts. When the problem of hydraulic oil leakage occurs, after removing the lack or uneven torque of the fastening bolt, it should also be checked whether the pressure is excessive before replacing the oil seal that may have been severely worn or damaged. When installing the oil seal, the type and quality of the oil seal should be checked, and the installation should be accurate.
Three trials
"Try" is to operate the actuator of the machine hydraulic system, and determine the fault location and cause from its operating condition.
(1) Comprehensive test. According to the planning function of the hydraulic system, the test is done one by one to determine whether the fault is in some areas or in the whole area. If the full maneuver fails or is weak, the first thing to check is whether the pilot operating pressure is normal, whether the clutch (connecting shaft) is slipping (loose), whether the initiating power is met, whether the hydraulic oil is enough and the seal status of the hydraulic pump inlet. The fault symptom of energy-saving excavator is only manifested as the active fall of the boom, then the cause of the fault may be in the oil circuit of the reversing valve, overload valve or hydraulic cylinder, and has nothing to do with the hydraulic pump and the main safety valve.
(2) Communication test. When only a certain primary circuit or a function is lost in the hydraulic system, the oil circuit with the same (or related) function can be communicated to further determine the fault location.
Four touches
"Touch" is the use of active fingers to feel, to see whether the pipeline or component of the pressure system occurs oscillation, impact and abnormal oil temperature rise and other problems. If you touch the pump shell or hydraulic parts by hand, according to the degree of cold and heat, you can identify whether the hydraulic system has abnormal temperature rise, and determine the cause and location of the temperature rise. If the pump housing is overheated, it means that the pump is severely drained or air is sucked in. If the oscillation is abnormal, it may be that the balance of the reverse component device is not good, the fastening screw is loose, or there is gas in the system.
The first thing to test is the output power of the initiator itself. If the output power of the initiator is lower than the rated power, The cause of the problem may be poor fuel quality, low fuel pressure, wrong valve gap, a cylinder of the starter does not work, wrong injection timing, wrong setting of fuel amount, air leakage of the intake system, faulty brake and its operating rod and carbon accumulation of the turbocharger.