Views: 1 Author: WGT Publish Time: 2021-11-24 Origin: WGT
The lubrication of gear reducer is of great significance for prolonging its service life, and lubrication can effectively improve the transmission efficiency of gear and the working efficiency of metallurgical machinery and equipment. The following mainly introduces the relevant points of lubrication for mechanical gear reducer.
Selection essentials of lubricating oil for mechanical gear reducer
1. Select lubricating oil with appropriate quality
Gears need high load and cyclic operation, so the selected lubricating oil must have strong oxidation resistance, durable, not easy to change, and easy to precipitate water and dirt. It is usually appropriate to select circulating engine oil. Circulating oil containing antioxidant and antirust additives has better oxidation resistance, durability and antirust. Extreme pressure oils containing anti-wear agents or extreme pressure additives should be selected.
2. Selection of lubricating oil or grease
Some machines can be lubricated freely without difficulty by using lubricating oil or grease. However, the most fuel-efficient and economical one shall be selected.
Generally speaking, the heat dissipation capacity of lubricating oil is better than that of grease, the friction coefficient is small, the use and addition are simple, and the oil film formed is more uniform. As for lubricating grease, it has the characteristics that lubricating oil does not have: mechanical lubrication is required not to drip oil; If the oil retaining ring is perfect, the grease is not easy to leak, and there is no need to add oil for a long time; At higher temperatures, the grease is not easy to thin; The grease itself also has the function of protecting the bearing; The lubrication cycle must be extended for parts that are not easy to refuel; If the oil retainer is good, the effect of preventing dirt intrusion is better.
3. Grasp of oil viscosity
Viscosity is the most basic factor to achieve perfect lubrication (that is, the foundation of forming oil film on two friction surfaces). If the viscosity is too low, the direct friction between metal and metal is easy to occur. If the viscosity is too high, the internal resistance of oil will be increased. Neither of them is appropriate. Generally, select the lower viscosity suitable for a specific machine, and the viscosity should not be too thick. The temperature of lubricating parts, journal speed, load and clearance between lubricating parts also directly affect the demand for viscosity.
4. Selection of lubrication mode
The lubrication method also affects the selection of lubricating oil. For those who use divergent oil supply, oil bath oil supply, circulating oil supply, oil ring oil supply and other methods to refuel, the oil is not only used repeatedly in the lubrication system, but also often dispersed into very small oil droplets and in contact with the air, which is prone to oxidation, at least high-quality and durable oil, such as circulating engine oil, etc. It is better to contain antioxidant and antirust additives and have good antioxidant and antirust properties.
5. Suitable for environmental conditions
The surrounding environment during mechanical operation also directly affects the selection of lubricating oil.
The temperature around the machine directly affects the requirements of oil viscosity. When the surrounding temperature is high, the oil with higher viscosity number shall be selected; On the contrary, if the temperature is lower, the oil with lower viscosity number can be used. For example, when the temperature of the vehicle is below 0 ℃, the oil with sae10w viscosity number shall be used, while when the temperature is above 32 ℃, the oil with sae50 number shall be used. In addition, when the oil is operated at a temperature below 57 ℃, the oxidation is not obvious; However, when the temperature exceeds 60 ℃, the oxidation rate will double for every 10 ℃. Therefore, when the oil in the oil pressure system exceeds 60 ℃, the service life will be halved for every 10 ℃ increase. The oxidation resistance of super grade circulating oil containing antioxidants is about five times or more than that of advanced circulating oil without additives. In order to reduce the temperature of the oil in the lubrication parts and lubrication system, oil coolers or heat sinks are often installed to prolong the service life of the oil and maintain a certain viscosity of the oil.
If the humidity in the atmosphere is high and the machinery is easy to rust, the oil containing anti rust additives shall be used. As another example, when the salt in the air is high, the oil with anti rust function to seawater should be used.
Selection of lubrication mode for gear reducer of mechanical equipment
The lubricating oil of the gear must be selected according to the type, running speed, reduction ratio, rotation number, load and refueling method of the gear. The service conditions of gears vary greatly, such as ambient temperature, humidity, atmosphere and other environmental conditions. Therefore, when selecting lubricating oil, these conditions must be considered together. The actual situation is that, for example, the lubricating oil recommendation benchmark of the machinery manufacturer should also be regarded as an important item. Taken together, it is necessary to review these items. In addition, although it is gear oil, it has a wide variety. The main representative specifications include JIS, API, AGMA, SAE, etc. if it is classified from the general quality, it includes pure mineral oil or Pao gear oil, spiral gear oil, extreme pressure EP gear oil and multi-purpose gear oil. These gear oils are subdivided according to viscosity.
Although the lubricating oil can also be used on open gears, in order to prevent the oil from splashing out or being squeezed out from the tooth surfaces, most lubricants with excellent oil adhesion and oil film strength are required. As the lubricating oil meeting these requirements, the compound oil mixed with animal and vegetable oil is generally used, but because of its high viscosity, the refueling method is limited and inconvenient. As for solvent diluent open gear oil with volatile solvents, the coating and spray oiling method can be used in any occasion. It is easy to use, and can form a strong film on the tooth surface. It is very convenient. However, due to the use of volatile solvents, it is necessary to be careful about its harmfulness and safekeeping methods. There are many cases of wear or rust of open gears due to the adhesion of dust and moisture, so we should try our best to prevent dust and water. At the same time, we must also use lubricating oil with excellent rust resistance.
1) The dropping refueling of lubricating oil is only limited to small and light load. For large and heavy load, it is best to use open gear oil. When using solvent diluted open gear oil, you must pay attention to the above situations.
2) When lubricating with grease, cement machinery, etc. because dust is particularly easy to adhere to the grease, it will become a cause of increased wear when used for a long time. Therefore, it is necessary to wipe the old grease and dust regularly and apply new grease.
3) The slip of spiral gear (worm gear) is very large, and because the oil between worm and wheel will be strongly squeezed, it is difficult to completely maintain the oil film. Therefore, high viscosity oil with strong oil film and good lubricity must be used.
In terms of quality, spiral gear oil and even EP gear oil with mineral oil and grease or oily agent can be recommended. In addition, if the worm is located in the upper structure, oil film consumption is easy to occur during starting, so special attention should be paid, especially when selecting the spiral gear lubricating oil under low temperature conditions, it is best to consult with the lubricating oil manufacturer. When using conical worm gear, the formation of oil film is particularly difficult, so lubricating oil with high viscosity and excellent lubricity must be used.