One, select the principles of hydraulic oil
1, choose the basis of the hydraulic oil
(1) hydraulic parts. Different hydraulic components used in the hydraulic oil has a minimum configuration requirements, so the choice of hydraulic oil hydraulic type and use of materials, seals and coatings or paint compatible with the hydraulic oil to ensure that all deputy campaign well-oiled, so that the components meet the design life, to meet the performance requirements.
Hydraulic pump is the most sensitive one of the components of the hydraulic oil viscosity and viscosity-temperature performance, therefore, often the requirements of the system pump hydraulic oil as an important basis for choice of hydraulic oil (servo valve system).
(2) system conditions. If the executive body speed, system pressure, and body movements, the accuracy requirements of the higher, the higher the wear and load carrying capacity, such as the requirements of the hydraulic oil.
Possible by the system operating temperature, continuous operation time and the working environment and hygiene conditions, choose the oil should be noted that the oil viscosity, high temperature performance and thermal stability to reduce sludge formation and deposition.
(3) fuel tank size. The smaller the tank the oil oxidation stability, extreme pressure abrasion resistance, higher air release and filtration requirements.
(4) ambient temperature. Hydraulic oil in the ground, water, indoor, outdoor, cold areas, or in the temperature cold area and the nearby whether the high temperature heat or open flame, ambient temperature characteristics, and reasonable choice. If no open flames near the operating temperature below 60 ℃, carrying lighter, you can use an ordinary hydraulic oil, if the equipment required to start in the low temperature, are required to use low pour hydraulic oil.
In summary, if the hydraulic oil of acceptable quality, the system performs high velocity fluid flow rate is also high, the hydraulic loss increases, but leakage is relatively reduced, it should choose the lower viscosity oil; , when the oil flow rate is low, the amount of leakage is relatively increased, will be working bodies of the velocity of impact, it should choose the higher viscosity of oil. Normally, when work pressure is high, should use the high viscosity of the hydraulic oil, because to solve the leak problem should give priority to more than overcome the viscous resistance in hypertension; when working pressure is low, should use low viscosity oil. Ambient temperature is high, the higher viscosity of oil, to the contrary, the lower viscosity oil should be used.
(5) The final determination of the hydraulic oil. Hydraulic oil is initially selected, and pay attention to the verification of their supply, viscosity, and quality characteristics, the scope of application and compatibility of materials, systems and components, to see whether the indicators fully meet the requirements.
(6) economy. Considering the price of the hydraulic oil, life, and the hydraulic system and maintain safe operation of the cycle, etc., focus on the economic benefits of a good brand.
2, the economic analysis to select the hydraulic oil
Choice of hydraulic oil, can not only pay attention to oil prices, while ignoring the variety, quality, maintenance and regeneration, such as high temperature heat and open flames, high temperature, high pressure and sophisticated hydraulic system should I use liquid phosphate ester fire resistant hydraulic oil cheap water content, not because of the price of your fire resistant fluid instead, this would allow the hydraulic pump to premature wear, reduce system accuracy; another example, in the high-pressure hydraulic system, anti-wear hydraulic oil should be used, if the choice of cheap machine oil or antirust, antioxidant hydraulic oil, hydraulic pump life will be shortened. YB-D25 ISO viscosity grade VG46 the varieties L,-the HH and L-HM oil as an example, respectively, for the same vane pump (the pressure of 12.5MPa, the temperature was 65 ° C, speed of 1500r/min), continuous The amount of wear measured amount of wear after running 250h L-HH oil pump for L-HM oil 63 times. Therefore, the high pressure system should not use the L-HH or L-HL oil, L-HM Anti-wear hydraulic oil should I use.
Cold regions and cold compartment for operating high-pressure system, lower in temperature, ambient temperature changes, should be selected high viscosity index, low-temperature hydraulic oil, to make low-temperature oil flow, good cold start easy, but also make system in the winter and summer oil, will not change frequently.
High-quality anti-wear hydraulic oil, high thermal stability, good hydrolytic stability, and ability to break the emulsion, the air release time is short, long life, can improve the health of the system, therefore, high-performance hydraulic system shall be provided with high quality the hydraulic oil.
Selection of high quality hydraulic oil, although oil prices are high, long service life of the oil, hydraulic components, less wear and tear, the system easy to maintain high production efficiency, so the overall cost-effectiveness or cost-effective.
Two, the rational use of hydraulic oil
1, the quality of the factors affecting hydraulic oil
(1) water. Oil water content of the water in accordance with the technical standards of the GB GB/T1118.1-94 test the quality indicators should be not more than traces. If excessive moisture in the oil must be replaced; otherwise, will not only damage the bearing, but also steel surface rust, thereby enabling the hydraulic oil emulsion, deterioration and generate sediment hinder the cooler thermal conductivity affect the valve, reducing the oil filters have an effective work area, increasing the abrasive action of the oil.
(2) oxidation. General mechanical work of the hydraulic oil temperature to 30-80 ° C, the life of its operating temperature of the hydraulic oil is closely related to the experience tells us that when the working oil temperature exceeds 60 ℃, an increase of 8 ° C, the oil life will be halved, 90 ° C oil life expectancy is about 60 ℃ for 10% of the oil, because oil is oxidized. Carry out the reaction of oxygen and hydrocarbons in the oil, the oil slowly oxidized, black color, viscosity rise, and may end up seriously to the oxide can not be dissolved in the oil, brown mucus layer deposition in the system somewhere, easy to plug components of the control oil passages, ball bearings, spool, hydraulic pump piston wear increased, affecting the normal operation of the system. Oxidation also produce corrosive acid. Oxidation process begins slowly, and when you reach a certain stage, the oxidation rate suddenly accelerates, the viscosity will be followed by a sudden increase, resulting in work temperature rise, the faster the oxidation process, the accumulated sediment and acid will be more Finally, the oil can not be reused.
(3) impurities. Impurities can not only wear the various moving parts, and once they are stuck in the spool or the other deputy campaign will affect the normal operation of the entire system, cause the machine to malfunction.
(4) air. Hydraulic oil containing gas, wall and components of the bubbles overflow will impact the formation of cavitation, the system is not working properly, a little longer will result in component damage.
(5) physical and chemical reactions. The fuel tank shall clean the paint, etc., will lead to changes in the chemical properties of oil.
2, inspection and maintenance of oil
Water content: The release of 2-3cm3 oil to a test tube, put it aside for a few minutes to make the bubbles disappear, and then heating the oil (such as with a lighter), while at the top of the test tube mouth attention to listen to whether there is water vapor slight "bang bang" sound If so, then the oil contains water.
Generally do not have the conditions to carry out the inspection of the system, oil water content, the easiest way to inspection machine after standing overnight, the tank bottom oil drain plug open and emit a little oil into a container, field observation of oil if contains water.
Odor and appearance: the unused oil and used oil oil sample a, in the same temperature and the glass dish in comparison, if the color of the oil very different or have a special smell, the spent The oil has gone to be replaced. If no significant difference between two kinds of oil-like color and odor, can be two kinds of oil samples at the same time place a night, if equipped with a container of used oil appears at the bottom of the precipitation, the oil system must go through the fine filter oil for filtering and cleaning the tank.
In addition, attention should be paid the following oil matters:
(1) before starting to check the oil level, check the opening of each oil is in the correct standby.
(2) 5min or so the machine idling, check the level gauge oil bubbles, if a new car or change the hydraulic oil, idle air bubbles in the oil standard is normal to allow the machine to work the bubbles disappear.
(3) pay close attention to the temperature of the oil. When the machine working for some time, if the oil temperature high is best to stop to rest, until the oil temperature to normal and re-work, to extend the life of the system with the oil.
(4) should be noted that the values ??of various parameters of the hydraulic system is normal and pay attention to the system external characteristics - sound. If the system inlet water or oil poor, is issued by the abnormal sound. Meter reading fluctuations in value is not normal, should be promptly shut down, the investigation.
(5) filter hydraulic oil on a regular basis. Impurity particles in the oil control within the limits prescribed.
(6) Replace the hydraulic oil on a regular basis. Oil change on a regular basis in accordance with the requirements of the specification of the machine, replace the oil filter, conditional detection should be based on the results to determine whether oil; to develop the oil change intervals can also be based on the mechanical use of the venue and system requirements, and drain intervals included in the equipment technical file.
Note: The oil change new oil and old oil should be the same specifications of the same grade, oil, used oil should be all done and rinse the body, hydraulic cylinders, etc., put not they wash not return lines can be opened into a temporary barrels, adding a new oil, to move the engine so that the new oil replacement of old oil out, the principle is to inject new oil must be subject to not less than the system filtration accuracy The oil filter filter, if the site is indeed unconditional, should replace the oil filter system by adding new oil to run about 1h; machine by a new oil idle, should re-check the oil level, if necessary, continued to add new oil.
(7) when not in the car wash or machine of the tank should be hooded to prevent the moisture in the air to enter.



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