1. The selection of appropriate hydraulic oil plays the role of pressure transmission, lubrication, cooling and sealing in the hydraulic oil system. The improper selection of hydraulic oil is the main reason for the early failure and durability decline of the hydraulic system. The hydraulic oil shall be selected according to the brand specified in the attached operation manual. When it is necessary to use alternative oil under special circumstances, its performance shall be the same as that of the original brand.
2. Precautions for regular maintenance at present, some hydraulic systems of construction machinery are equipped with intelligent devices, which have warning function for some hidden dangers of the hydraulic system, but their monitoring scope and accuracy have certain limitations. Therefore, the inspection and maintenance of the hydraulic system should combine the monitoring results of intelligent devices with regular inspection and maintenance.
(1) 250h inspection and maintenance: check the attachments on the filter screen. If there is too much metal powder, it often indicates that the oil pump is worn or the oil cylinder is pulled.
(2) 500h inspection and maintenance after 500h operation of construction machinery, the filter element shall be replaced regardless of the condition of the filter element, because it is difficult to detect the small damage of the filter element with the naked eye. If it is operated at high temperature for a long time, the filter element shall be replaced in advance.
(3) 1000h inspection and maintenance. At this time, the filter should be cleaned, the hydraulic oil tank should be cleaned, and the filter element and hydraulic oil should be replaced. The oil change time for long-term high-temperature operation should be properly advanced.
(4) 7000h and 10000h inspection and maintenance at this time, the hydraulic system of construction machinery needs to be tested by professionals 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. Prevent solid impurities from mixing into the hydraulic system. Clean hydraulic oil is the life of the hydraulic system. There are many precision coupling parts in the hydraulic system, some of which are equipped with damping holes or gaps. If solid impurities invade, it will cause strain of precision coupling parts, hairpin, oil duct blockage, etc., which will endanger the safe operation of hydraulic system.
4. Prevent air and water from invading the hydraulic system
(1) Prevent air from invading 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, the air will be separated from the oil, and the bubble will break, causing "cavitation" of hydraulic components and noise. 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 "crawling" of actuator. In addition, air will oxidize the hydraulic oil and accelerate its deterioration.
(2) Prevent water from invading the hydraulic system. Excessive water in the hydraulic oil will rust the hydraulic components, emulsify and deteriorate the oil, reduce the strength of the lubricating oil film, and accelerate mechanical wear. In addition to preventing moisture intrusion during maintenance, pay attention to tighten the cover of the oil storage barrel when not in use, and it is best to place it upside down; The hydraulic oil with large water content shall be filtered for many times, and the dried filter paper shall be replaced every time. When there is no special instrument to detect, the hydraulic oil can be dropped on the hot iron plate. The filling can be carried out only after there is no steam and burning immediately.
