Maintenance technology of hydraulic system of engineering machinery

1. Selecting suitable hydraulic oil plays the role of transferring pressure, lubrication, cooling and sealing in the hydraulic oil system. Improper selection of hydraulic oil is the main reason for the early failure and durability decline of the hydraulic system. Hydraulic oil shall be selected according to the brand specified in the random operation manual. When the substitute oil is needed in special cases, the performance shall be the same as that of the original brand.

 

At present, some construction machinery hydraulic system is equipped with intelligent device, which has warning function for some hidden dangers of hydraulic system, but its monitoring range and accuracy is limited to a certain extent. Therefore, the inspection and maintenance of hydraulic system should combine the monitoring results of intelligent device with regular inspection and maintenance.

 

(1) 250h inspection and maintenance inspection: the attachment on the filter screen of the filter cleaner, such as too much metal powder, usually indicates oil pump wear or oil cylinder pull cylinder.

 

(2) after 500h inspection and maintenance engineering machinery runs for 500h, the filter core should be replaced regardless of the condition of the filter core, because it is difficult to detect the small damage of the filter core by naked eyes, and the filter core should be replaced in advance if the operation takes a long time in high temperature.

 

(3) the filter should be cleaned, the hydraulic oil tank should be cleaned, the filter core and hydraulic oil should be replaced at the time of 1000h inspection and maintenance. The oil change time of long-term high-temperature operation should be appropriately advanced.

 

(4) the hydraulic system of construction machinery at 7000h and 10000h shall be inspected by professional personnel for necessary adjustment and maintenance. According to practice, the imported hydraulic pump and hydraulic motor must be overhauled after working for 10000h. Otherwise, the hydraulic pump and hydraulic motor may be damaged due to disrepair, which is fatal to the hydraulic system.

 

3. Preventing solid impurities from mixing into the clean hydraulic oil is the life of the hydraulic system. Hydraulic system has many precision components, some with damping holes or gaps. If the solid impurities invade, it will cause the damage of the precision parts, the card, the blockage of oil channel and so on, which will endanger the safe operation of the hydraulic system. (the most technology is WeChat's most powerful technical information platform, like to pay attention to the most technology! Search for the most technical or man-machine concerns.

 

4. Prevent air and water from invading hydraulic system

 

(1) prevent air intrusion into the hydraulic system. Under normal pressure and temperature, the hydraulic oil contains air with a volume ratio of 6%~8%. When the pressure is reduced, air will free from the oil. A large amount of air entering the oil will aggravate the phenomenon of "cavitation", increase the compressibility of hydraulic oil, work instability, reduce work efficiency, and the "creep" of actuator. In addition, air will also make the hydraulic oil oxidize, accelerating its deterioration.

 

(2) to prevent water intrusion into the hydraulic system, excessive water in the hydraulic oil will cause the hydraulic components to rust, the oil emulsion will deteriorate, the oil film strength will be reduced, and the mechanical wear will be accelerated. In addition to maintenance to prevent water intrusion, attention should also be paid to the oil storage tank when not in use to tighten the cover, preferably placed upside down; The hydraulic oil with high water content shall be filtered for many times, and the drying filter paper shall be replaced once every time. When there is no special instrument to test, the hydraulic oil can be dropped on the hot iron plate, no steam out and immediately combustion before refilling.

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