For mechanized construction enterprises, the technical situation of construction machinery is good or not the direct production of enterprises can be a direct factor. In terms of hydraulic transmission of construction machinery, the normal operation of the hydraulic system is a good sign of its good technical condition. Qualified hydraulic oil is the reliable operation of the hydraulic system protection, the correct maintenance is the fundamental operation of the hydraulic system. To this end, I work according to the practice, the general operating environment in the construction machinery hydraulic system maintenance for a rough discussion.

1. Select the appropriate hydraulic oil
Hydraulic oil in the hydraulic system plays a transfer pressure, lubrication, cooling, sealing the role of hydraulic oil selection is not appropriate hydraulic system early failure and the main reason for the decline in durability. The hydraulic oil should be selected according to the grade specified in the random “instruction manual”. In case of using the substitute oil, the performance should be the same as that of the original grade. Different grades of hydraulic oil can not be mixed to prevent the hydraulic oil to produce chemical reactions, performance changes. Dark brown, milky white, smell the oil is metamorphic oil, can not be used.

2. Prevent solid impurities from entering the hydraulic system
Clean hydraulic oil is the life of the hydraulic system. There are many precision coupling in the hydraulic system, some with damping holes, and some gaps and so on. If the solid impurity invasion will result in precision even pieces of injury, hairpin, oil blockage, etc., endangering the safe operation of the hydraulic system. General solid impurities to invade the hydraulic system through: hydraulic oil is not clean; refueling tool is dirty; refueling and maintenance, maintenance carelessness; hydraulic components desquamation and so on. Can prevent the solid impurities from the following aspects of the invasion system:

2.1 when refueling
Hydraulic oil must be filtered and refueled, and the refueling tool should be clean and clean. It is not possible to remove the filter at the tank filling point in order to increase the fueling speed. Refueling personnel should use clean gloves and overalls to prevent solid impurities and fiber impurities from falling into the oil.

2.2 when maintenance
Remove the hydraulic tank fueling cover, filter cover, detection hole, hydraulic tubing and other parts, resulting in the system when the oil channel to avoid dust, the demolition of the site must be thoroughly cleaned before opening. If you remove the oil tank cover, remove the dirt from the tank cover, loosen the tank cover, remove the debris remaining in the joint (can not be washed with water to avoid water infiltration tank), confirm the cleaning before opening the fuel tank cover. If you need to use the wipe material and hammer, you should choose not to wear fiber impurities and rubbing the material attached to the rubber hammer. Hydraulic components, Hydraulic Hose to be carefully cleaned, with high pressure air dry after assembly. Selection of packaging integrity of the genuine filter (inner packaging damage, although the filter is intact, it may be unclean). Oil cleaning at the same time cleaning the filter, the application of the filter before the application of cleaning materials carefully clean the bottom of the filter shell dirt.

2.3 cleaning of the hydraulic system
The cleaning oil must use the same hydraulic oil as the system, with an oil temperature between 45 and 80 ° C, with large flow as much as possible to remove impurities from the system. Hydraulic system to be cleaned more than three times, after each cleaning, while the oil heat to release all of the system. After cleaning and then clean the filter, replace the new filter and add new oil.

3. Prevent air and water from intruding into hydraulic systems

3.1 to prevent air intrusion hydraulic system
At atmospheric pressure, the hydraulic fluid contains air with a volume ratio of 6 to 8%. When the pressure is reduced, the air is free from the oil. The bubble is broken and the cavitation is generated. A lot of air into the oil will make the “cavitation” phenomenon intensifies, hydraulic oil compression increases, work instability, reduce efficiency, the implementation of components work “crawling” and other adverse consequences. In addition, the air will make the hydraulic oil oxidation, to accelerate the deterioration of oil. To prevent air invasion should note the following:

1, after repair and oil change according to the random “manual” provisions to exclude the air in the system in order to normal operation.

2, the hydraulic pump suction pipe mouth shall not be exposed to oil, suction piping must be sealed well.

3, the pump drive shaft seal should be good, pay attention to the replacement of the oil seal should use the “lips” genuine oil seal, can not use “single lip” oil seal instead, because the “single lip” oil seal can only one-way seal oil, do not have Closer function. The unit had a Liugong ZL50 loader overhaul, the hydraulic pump appeared continuous “cavitation” noise, oil tank oil level automatically increased and other failures, the query hydraulic pump repair process, found that the hydraulic pump drive shaft oil seal misuse ” Single lip “caused by oil seal.

3.2 to prevent water intrusion hydraulic system
Oil contains excessive moisture, will make the hydraulic components rust, oil emulsion deterioration, lubricating oil film strength, speed up mechanical wear. In addition to maintenance to prevent moisture invasion, but also pay attention to the oil tank when not in use, to tighten the lid, the most Good inversion placed; water content of the oil to be filtered several times, each filter once to replace a dry filter paper, in the absence of special equipment testing, the oil can be heated to the hot iron plate, no steam and Immediately burn can only raise.

4. Note in the operation

4.1 mechanical work to be gentle and smooth
Mechanical operation should avoid rough, otherwise it will inevitably produce shock load, so that mechanical failure frequently, greatly shorten the service life. The impact load generated on the one hand, on the one hand the mechanical structure of early wear, fracture, broken, on the one hand the hydraulic system to produce the impact pressure, the impact of pressure will damage the hydraulic components, oil seal and high pressure tubing joints and hose Premature failure of oil spill or burst pipe, overflow valve frequent action oil temperature rise