The commonly used gearbox lubrication methods include gear oil lubrication, semi fluid grease lubrication and solid lubricant lubrication. Gear oil can be used for those with good sealing, high speed, large load and good sealing performance; For those with poor sealing performance and low rotating speed, semi fluid grease can be used for lubrication; Molybdenum disulfide superfine powder can be used for lubrication in oil forbidden occasions or high temperature occasions.
The lubrication system of the gearbox is of great significance to the normal operation of the gearbox. Large wind power generation gearbox must be equipped with a reliable forced lubrication system to inject oil into the gear mesh area and bearings. Insufficient lubrication accounts for more than half of the causes of gearbox failure. The temperature of lubricating oil is related to the fatigue of components and the life of the whole system. - Generally, the maximum oil temperature of the gearbox during normal operation shall not exceed 80 ℃, and the temperature difference between different bearings shall not exceed 15 ℃. When the oil temperature is higher than 65 ℃, the cooling system starts to work; When the oil temperature is lower than 10 ℃, start the machine after heating the lubricating oil to the preset temperature.
In summer, because the wind turbine is in full operation for a long time, and the high altitude direct sunlight, the operating temperature of oil products rises above the set value; When used in winter in the northeast cold region, the lowest temperature often reaches below - 30 ℃, the lubricating oil in the lubricating pipeline is not flowing smoothly, and the lubrication of gears and bearings is not sufficient, which causes the gearbox to stop at high temperature, and the tooth surface and bearings to wear. In addition, the low temperature will also increase the viscosity of the gearbox oil. When the oil pump is started, the load is heavy, and the oil pump motor is overloaded.
The gearbox lubricating oil has an optimal temperature range for operation. It is recommended to design a lubricating oil thermal management system for the gearbox lubricating system: when the temperature exceeds a certain value, the cooling system starts to work; when the temperature is lower than a certain value, the heating system starts to work, and the temperature is always controlled within the optimal range. In addition, improving the quality of lubricating oil is also an important aspect that must be considered in the lubrication system. Lubricant products must have excellent low temperature fluidity and high temperature stability, and the research on high-performance lubricating oil should be strengthened.
