The lubrication of gear reducer is of great significance for the extension of its service life. Moreover, the transmission efficiency of gear can be effectively improved and the working efficiency of metallurgical machinery and equipment can be improved by lubrication. Metallurgical machinery and equipment such as coke making machine, coke pusher, limestone and ore sintering equipment, large blower, ore bucket traction wire rope and other furnace top equipment, chemical furnace, blast furnace, belt conveyor, etc., that is to say, metallurgical machinery equipment is usually exposed to dust or corrosive dust environment, which is prone to corrosion, cavitation and wear. Therefore, it is necessary to lubricate the transmission parts of metallurgical machinery equipment such as bearings, gears, wire ropes, etc; The dry oil lubrication system of No. 0 or No. 1 extreme pressure lithium grease can be used for lubrication of large blast furnace, ore bucket traction wire rope and other furnace top equipment. The top machinery can be lubricated by phosphate refractory liquid as hydraulic medium. The hot metal car is loaded and the temperature is high, and it needs to be lubricated with lithium grease with the drop point greater than 125 ℃. The following mainly introduces the lubrication points of gear reducer of metallurgical machinery.

1、 Structural characteristics of gear reducer for metallurgical machinery

Gear reducer is based on gear, worm and bearing as supporting components. The common gear reducers in metallurgical machinery include worm, helical gear, umbrella and helical gear worm reducer. When selecting different types of gear reducer, the bearing selection of metallurgical machinery is different, which is usually divided into angular contact bearing and radial contact bearing. The inner cavity of gear box is connected with the bearing. The main transmission of gear reducer in metallurgical machinery equipment is mainly through the relative movement of gear and bearing, so it needs more mechanical work, and the meshing surface between bearing and gear needs greater lubrication, in order to ensure that the gear has better transmission efficiency, and can ensure that the spur gear and bearing have enough long service life.

2、 Selection of lubricating oil for gear reducer of metallurgical machinery

1. Choose suitable quality lubricating oil
Gears need high load and circulating operation, so the selected lubricating oil must have strong oxidation resistance, durable, not easy to change itself, and easy to precipitate water and dirt, so it is usually appropriate to select circulating oil. The circulating oil containing antioxidants and antirust additives has better antioxidation, durability and antirust properties. Extreme pressure oil containing antiwear agent or extreme pressure additive 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, it should be selected according to the most fuel-efficient and economical one. Generally speaking, the heat dissipation capacity of lubricating oil is better than that of grease, with small friction coefficient, easy to use and add, and uniform oil film. As for lubricating grease, it has the characteristics that lubricating oil does not have: mechanical lubrication requires that no oil can be dripped; If the oil guard ring is perfect, the grease is not easy to leak, and there is no need to add oil for a long time; At higher temperature, the grease is not easy to thin; The grease itself can also protect the bearing; The lubrication period must be extended for parts that are not easy to be lubricated; If the oil guard ring is good, the effect of preventing dirt invasion is better.

3. Oil viscosity control

Viscosity is the most basic factor to achieve satisfactory lubrication (that is, the formation of oil film on the two friction surfaces). If the viscosity is too low, direct friction between metal and metal is easy to occur, and if the viscosity is too high, the internal resistance of oil will be increased. Generally, it is enough to choose a 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 lubricating method also affects the selection of lubricating oil. Most of the oil is supplied by means of divergent oil supply, oil bath oil supply, circulating oil supply, oil ring oil supply, etc. the oil is not only used repeatedly in the lubrication system, but also often dispersed into tiny oil drops to contact with the air, which is prone to oxidation. At least high-quality and durable oil, such as circulating oil, is required. It is better to contain anti-oxidation and anti rust additives with good anti-oxidation and anti rust properties.

5. Suitable for environmental conditions

The temperature around the machine directly affects the requirement of oil viscosity. When the ambient temperature is high, the oil with higher viscosity should be selected; On the contrary, the oil with lower viscosity can be used for the oil with lower temperature. For example, when the temperature of the vehicle is below 0 ℃, SAE 10 W oil should be used, and when the temperature is above 32 ℃, SAE 50 oil should be used. In addition, the oxidation of oil is not obvious when the temperature is below 57 ℃; However, over 60 ℃, the oxidation rate doubled for every 10 ℃ increase. Therefore, when the oil temperature 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 oil in lubricating parts and lubricating systems, oil coolers or heat sinks are often installed to extend the service life of oil and maintain a certain viscosity of oil.

If the humidity in the atmosphere is high and the machinery is easy to rust, the oil containing anti rust additive shall be used. If the salt content in the air is high, the oil with antirust function for seawater should be used.

3、 The choice of lubrication mode of gear reducer for metallurgical machinery equipment

1. Closed gear

The lubricating oil of gear must be selected according to the type of gear, running speed, reduction ratio, number of revolutions, load and oil filling method. The service conditions of gears are various, 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 standard of machinery manufacturers should also be regarded as an important item. In general, it is necessary to review these items. In addition, although it is gear oil, it has a wide variety of specifications, mainly including JIS, API, AGMA, SAE, etc. if classified from the general quality aspect, there are pure mineral oil or R & O gear oil, spiral gear oil, EP gear oil and multi-purpose gear oil, which are subdivided according to viscosity.

2. Open impeller

Although lubricating oil can also be used in open gear, in order to prevent the oil from splashing out or being extruded from the tooth surface, most of the lubricants with excellent adhesion and film strength are required. As a lubricant meeting these requirements, the compound oil mixed with animal and vegetable oil is generally used, but because of its high viscosity, the oiling method is limited and the usage is 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 open gear wear or rust due to the adhesion of dust and water, so we should try our best to prevent dust and water, and at the same time, we must use lubricating oil with excellent rust resistance.

It is better to use open gear oil for large and heavy load, and pay attention to the above situation when using solvent diluted open gear oil.

When using grease lubrication, cement machinery, etc. are easy to attach dust on the grease, so long-term use will increase wear. Therefore, it is necessary to wipe the old grease and dust regularly before applying new grease.

Spiral gear (worm gear) has a high degree of smoothness, and because the oil between worm and wheel will be strongly squeezed, it is difficult to keep the oil film completely. Therefore, high viscosity oil with strong oil film and good lubricity must be used.

In terms of quality, it can be recommended that the spiral gear oil with mineral oil, oil or oily agent, or even EP gear oil. In addition, if the worm is located in the upper structure, it is easy to cause oil film loss when starting, so special attention should be paid, especially when selecting the spiral gear lubricant under low temperature conditions, it is best to consult with the lubricant manufacturer. When using conical worm gear, the formation of oil film is particularly difficult, so it is necessary to use high viscosity and excellent lubricating oil.