Lubrication of the hottest high-speed bearing I

Lubrication of high-speed bearings (I)

the difficulty of lubrication of high-speed bearings is that the lubricant is easy to fly away, and it is not easy to adhere to the rolling surface, or it is blocked by the high-speed air flow around the bearing and cannot enter the bearing, and the lubricant entering the bearing is too fast, sometimes the bearing will suffer damage, such as pitting and scaling of the cage, which will aggravate friction and wear

the working temperature of high-speed bearings is mostly around 200 ℃, and tends to be higher. Without strong cooling, the temperature will continue to rise, which is greatly detrimental to the strength and hardness of the bearing. Once the bearing loses the ability to maintain accurate shape, it will aggravate high-speed friction and make the temperature rise rapidly, which will further lead to the reduction of material strength and hardness and make the bearing fail soon

because high-speed bearings are sensitive to wear and easy to produce wear debris, if not removed from the bearings in time, it will also cause a vicious cycle and make the bearings fail quickly

therefore, the task of high-speed bearing lubrication must effectively deliver the lubricant to the moving surface in the bearing, take away the heat from the bearing, and remove the wear debris or dirt in the bearing at the same time

now the commonly used lubrication methods and effective lubricants in high-speed bearings are:

1 Spray lubrication method

spray lubrication method is a method of injecting lubricating oil into the bearing at a speed of 10 20m/s from the nozzle hole close to the bearing, usually into the gap formed between the cage and the inner or outer ring, so as to lubricate and cool the bearing

for small ball bearings with an inner diameter of mm, the DMN limit that jet lubrication can reach is 3million, and for larger bearings, it is 2.5 million

double hole or multi hole nozzles can not only increase the oil supply, but also improve the efficiency of lubricating oil. Multiple nozzles or nozzles on both end faces can improve the effect of lubrication and cooling. However, when the DMN value is close to 2million, due to the influence of centrifugal inertia and wind resistance, the oil sent into the bearing is only 70% or less of the nozzle flow

2. Under ring lubrication method

under ring lubrication method uses centrifugal inertia to spray oil directly to the raceway surface through many radial holes on the inner ring when the friction coefficient of the bearing surface decreases by 20%, and a part of the oil flows axially under the inner ring to cool the inner ring. The oil entering the raceway is divided into two channels to flow out, and the debris falling from the cage and other parts is washed away by the way

this lubricant exhibition will also hold icamem2014 International Conference on advanced materials and engineering materials, 2014 China (Ningbo) automotive Innovative Materials Technology Summit Forum, 2014 China Marine anti-corrosion and antifouling technology development forum to break the market monopoly, the Third International Academic Conference on advanced materials and powder metallurgy, 2014 high-end new military and civil dual-use materials demand utilization exchange, 2014 reinforcement materials and their composite materials development and utilization exchange In 2014, the annual meeting of the instrument functional materials branch of China Instrument and meter industry association and the "new materials class" of Ningbo University and other forum activities used much less oil than oil injection lubrication. The power loss caused by the dynamic mixing of oil is also less, the heating condition of the bearing has also been greatly improved, and even the temperature of the inner ring may be lower than that of the outer ring, reducing the bearing failure rate

this lubrication method can also be used to cool the outer ring. When the inner and outer rings are lubricated in this way, the allowable DMN value of the bearing can be further improved

now this under ring lubrication method is widely used in various ultra-high speed operation occasions. The maximum DMN value that can be achieved is 3million for large ball bearings with an inner diameter of 120 ~ 200 and a levelness of 0.2/1000mm; For tapered roller bearings with an inner diameter of 120mm, it is 2.4 million, while for short cylindrical roller bearings with combined inner rings, it is 3 million