Development trend of industrial Gear Oil: the improvement of gear box manufacturing technology and the specification evolution of industrial gear oil are two major factors affecting the development trend of industrial gear oil. 1. Development of Industrial Gear Equipment With the rapid development of the gear industry, the industrial gearbox is developing towards greater power, higher load and smaller volume, and the working environment is humid. The increase of the load increases the contact pressure of the tooth surface and the wear and pitting between metals; The reduction of gearbox volume means that there is less oil for lubricating gears and bearings, which will lead to the increase of oil temperature and accelerate the oxidation of oil. The sludge generated in the oxidation process will shorten the service life of oil and gearbox components; 2. Evolution of Industrial Gear Oil Specifications AIST 224 standard has always represented the highest specification of industrial gear oil, and the quality of L-CKD gear oil in the national standard GB 5903-2011 Industrial Closed Gear Oil formulated in China has reached this standard. In addition, the commonly used industrial gear oil specifications include the national standard ISO 12925, AGMA 9005-E02 EP in North America, and DIN51517-3 in Europe. From the above development of industrial gear manufacturing and industrial gear oil specifications, the future industrial gear oil should not only have good tribological properties, but also meet the requirements of energy conservation, environmental protection and safety as far as possible.
Application of Synthetic Base Oil in industrial gear oil 1. Application of PAO in Industrial Gear Oil In the early days, PAO was mainly used in the military industry. Until the late 1980s, with the significant growth of market demand and the progress of civil technology, PAO lubricating oil began to obtain large-scale application. In terms of preparation method, foreign companies mainly use ethylene copolymerization α- PAO base oils with different viscosities are prepared from sunflower hydrocarbons by catalytic oligomerization and hydrogenation saturation. because α- Because of its high purity, high catalytic activity and selectivity, and easy to strictly control the process conditions, the performance of the product is superior to that of PAO products prepared by wax hydrolysis, fractionation and re polymerization, mainly in the aspects of high viscosity index, good low-temperature performance, and good thermal oxidation stability. 2. Application of Synthetic Esters in Industrial Gear Oils Synthetic ester is another kind of widely used Base Oil for lubricating oil synthesis. It is an organic compound composed of ester functional groups obtained by esterification reaction dehydration of organic acids and organic alcohols under the action of catalyst. Its greatest feature is that the multiple ester bonds (- CO - OR) in the ester molecules endow the ester molecules with polarity, thus endowing ester oils with many incomparable properties: good thermal oxidation stability, excellent lubrication performance, solubility and biodegradability of polar substances. According to the number and position of ester groups in the molecule, synthetic esters are divided into monoesters, diesters, polyol esters and diesters. Polyol ester and double ester are mostly selected as the base oil of biodegradable gear oil, and their biodegradation rate is more than 70%. It should be noted that PAO type synthetic industrial gear oil will generally be added with a small amount of ester base oil. This is because PAO is difficult to dissolve additives, while ester oil can dissolve additives and also dissolve in PAO. Secondly, PAO will shrink the sealing rubber, while ester oil will expand the rubber. Therefore, when two base oils coexist, the impact on the sealing performance of the rubber will be offset. In addition, due to the biodegradability of synthetic esters, most biodegradable industrial gear oils choose synthetic esters as base oils. 3. Application of PAG in Industrial Gear Oil PAG is a linear polymer prepared by ring opening homopolymerization and copolymerization of ethylene oxide, propylene oxide, epoxy butane and other raw materials in the presence of catalyst. PAG base oil has extremely low friction coefficient, excellent lubricating performance, extremely high viscosity index, excellent low-temperature fluidity and excellent thermal oxidation stability. However, PAG lubricating oil is incompatible with mineral lubricating oil, some coatings and paints, so it is necessary to clean the lubricating system, use fluororubber or nitrile rubber seals, and use epoxy resin paint or no paint inside the lubricating system. Because PAG industrial gear oil has the characteristics of low friction coefficient, it is suitable for lubrication of gear pairs with many sliding forms, especially turbine and hyperbolic gears. There is almost no residue, gum and other deposits in the lubrication process, which can ensure that the lubrication system is clean, reduce the blockage of the lubrication system pipeline and precision valve, and effectively prevent equipment damage caused by low oil level or oil-free lubrication of the equipment due to the above reasons. PAG type industrial gear oil, such as Kunlun Synthetic Elevator Oil, is specially designed for worm gear applications, especially in heavy and harsh operating environments. To sum up, the three types of synthetic base oils have different properties and different application ranges. Poly α- Due to its good oxidation stability and low temperature fluidity, olefins (PAO) are commonly used for gear lubrication under extreme operating conditions; Synthetic esters are mostly used in biodegradable gear oil because of their good biodegradability; polyether (PAG) is often used for lubrication of worm gears because of its low friction coefficient.
