Precautions for maintenance of hydraulic system of large cranes

<

For mechanical construction companies, big cranes are an essential construction vehicle. Most cranes nowadays use electromechanical and hydraulic integration. The normal operation of the hydraulic system is a major sign of the technical situation. Qualified hydraulic oil is the prerequisite for reliable operation of the hydraulic system. Proper maintenance allows the hydraulic system to operate reliably. Xiao Bian said today about some hydraulic system maintenance precautions.

吊车,液压系统,维护

Only the maintenance of the hydraulic system can make the engineering machinery giant work better.

Hydraulic transmission technology has penetrated into all modern engineering fields. Compared with mechanical transmission and electric drive, hydraulic transmission has unique advantages: (1) Under the same volume, the hydraulic drive produces more power than the electric device: ( 2) In the case of the same power, the hydraulic transmission device is small in size, light in weight and compact in structure; (3) The hydraulic transmission has stable quality, high mechanical efficiency and good low-speed load characteristics.

Due to the friction loss and leakage loss, the hydraulic transmission system has a large energy loss; the cleanliness of the fluid is required to be high, and it is required to be replaced periodically; changes in the oil temperature will affect the control of speed and noise and other shortcomings. In addition, construction machinery is often exposed to mud and dust in outdoor work, under wind and rain. The operating load is often variable and accompanied by vibration, and the operating speed is often transient and inertial. Therefore, the hydraulic system of construction machinery should have special requirements: it should have good environmental adaptability and reliable closedness; it should have higher working reliability and the ability of sensitive real-time strain; it should have better maneuverability to make the system Closed and able to do a variety of changes. Therefore, when we use the hydraulic system, we should follow the relevant procedures.

1, choose the right hydraulic oil

Hydraulic oil plays a role in transmitting pressure, lubricating, cooling and sealing in the hydraulic oil system. The improper selection of hydraulic oil is the main reason for the early failure and durability of the hydraulic system. The hydraulic oil should be selected according to the grade specified in the random “operating instructions”. When special oils need to be used, the performance should be the same as the original grade. Different brands of hydraulic oil can not be mixed to prevent the hydraulic oil from producing chemical reactions and changes in performance. Dark brown, milky, smelly hydraulic oil is a deteriorating oil and cannot be used.

2, regular maintenance precautions

At present, some hydraulic systems of construction machinery are equipped with intelligent devices. The devices have warning functions for certain hidden dangers of the hydraulic system, but their monitoring range and accuracy have certain limitations. Therefore, the inspection and maintenance of hydraulic systems should be accompanied by the monitoring results of intelligent devices. Check the maintenance combination regularly.

Check the attachment on the filter screen. If there are too many metal powders, it may mark the wear of the oil pump or cylinder pull. In this regard, it is necessary to diagnose and take appropriate measures before starting up. If it is found that the filter is damaged and dirt accumulates, replace it promptly and replace the hydraulic oil if necessary.

3. The hydraulic oil for the hydraulic system must use the same hydraulic oil as that used in the system. The oil temperature should be between 45~80°C. Take away the impurities from the system with large flow. The hydraulic system should be cleaned more than three times, and all the oil should be discharged out of the system after each cleaning. After cleaning, clean the filter and replace the new filter with new oil.

4, to prevent air and water invasion of the hydraulic system

To prevent air from invading the hydraulic system, the hydraulic oil contains air with a volumetric ratio of 6% to 8% at normal atmospheric pressure. When the pressure is reduced, the air is released from the oil, and the air bubbles burst to make the hydraulic element “cavitation” and generate noise. The large amount of air entering the oil will increase the "cavitation" phenomenon, increase the compressibility of the hydraulic oil, make the work unstable, reduce the work efficiency, and cause adverse effects such as "crawling" of the actuator. In addition, the air will also oxidize the hydraulic oil and accelerate its deterioration. Prevent air intrusion should pay attention to the following points:

1) After maintenance and oil change, the air in the system shall be excluded according to the provisions of the "operating instructions".

2) The suction nozzle of the hydraulic pump must not expose the oil surface. The suction pipeline must be sealed well.

3) The seal of the oil pump drive shaft should be good. When replacing the oil seal, a “double-lip” genuine oil seal should be used instead of a “single-lip” oil seal, because the “single-lip” oil seal can only seal oil in one direction and does not have seal gas. The function. After a unit of the Liugong ZL50 loader was overhauled, the hydraulic oil pump suffered continuous “cavitation” noise and the oil tank oil level rose automatically. After consulting the hydraulic oil pump repair process, it was discovered that the hydraulic oil pump drive shaft oil seal was misused. Single lip" caused by the oil seal.

After reading the article, expect everyone to pay more attention to the maintenance of the crane hydraulic system.

After 500 hours of operation of the construction machinery, no matter how the condition of the filter element should be replaced, because the tiny damage of the filter element is difficult to detect with the naked eye, if the high temperature operation for a long time should also replace the filter element in advance.

At this time, the filter should be cleaned, the hydraulic oil tank cleaned, the filter element replaced, and the hydraulic oil replaced. Long-term, high-temperature operation should be performed in a timely manner. If you can guide oil change through oil detection analysis is the most economical, but pay attention to prolong the use of hydraulic oil, should be tested once every 100h, in order to promptly find and replace the deterioration of hydraulic oil.

At this time, the hydraulic system of the construction machinery needs to be inspected by a professional and necessary adjustments and maintenance are performed. According to practice, imported hydraulic pumps and hydraulic motors must be overhauled after 10,000 hours of operation. Otherwise, hydraulic pumps and hydraulic motors may be damaged due to disrepair, which is a fatal damage to the hydraulic system.

5, to prevent solid impurities mixed into the hydraulic system

Clean hydraulic oil is the life of the hydraulic system. There are many precision parts in the hydraulic system, some have damping holes or gaps. If the solid impurity invades, it will cause the precision joints to be damaged, card issuing and oil passage blocking, which will endanger the safe operation of the hydraulic system. Common solid material intrusion approaches include: impervious hydraulic oil; impure clean refueling equipment; refueling and careless maintenance; and hydraulic component descaling. Solid impurities can be prevented from invading the system in the following ways:

(1) The hydraulic oil must be filtered when refueling, and the refueling tool should be cleaned reliably. It is not possible to remove the filter at the filler port of the hydraulic tank in order to increase the refueling speed. Refuelling personnel should use clean gloves and work clothes.

(2) Remove the cover of the hydraulic oil tank, filter cover, detection hole, hydraulic oil pipe, etc. during maintenance, and avoid the dust when the oil passage of the hydraulic system is exposed. The dismantling site must be thoroughly cleaned before opening. When dismantling the hydraulic tank filler cap, first remove the dirt around the fuel tank cap, loosen the fuel tank cap and remove any debris that remains in the joint (do not flush it with water to prevent water from seeping into the tank). Make sure that the cap can only be opened after cleaning. If you need to use the wiping material and hammer, you should choose a wiping material that can not get rid of fiber impurities and a special hammer that hits the surface with rubber. Hydraulic components, hydraulic hoses should be carefully cleaned, and then assembled with high pressure air. Use a genuine, well-packed filter cartridge (if the packaging is damaged, it may be dirty even though the filter cartridge is intact). Clean the filter at the same time when changing the oil, and carefully remove the dirt from the filter housing by applying the wipe material before installing the filter element.


Professional Dc Charging Station manufacturer is located in China, including DC Ev Charger,Dc Charging Pile,Dc Fast Charging, etc.

Dc Ev Charger

Dc Charging Station,Dc Ev Charger,Dc Charging Pile,Dc Fast Charging

Shenzhen Hongjiali New Energy Co., Ltd. , https://www.hjlcharger.com