The core joint of aircraft engines - analyzing the key role of aviation bearings

At the recently concluded 15th China Airshow, many new aircraft engines such as AEF1200 and 177S attracted a lot of attention. As the pinnacle of modern industrial technology, the aircraft engine has an aircraft bearing inside, which is like a key "connection point" and is crucial to ensuring the reliability of the engine.

When the aircraft engine is running, the rotor can rotate at a speed of tens of thousands of revolutions per minute. Any slight error may cause huge centrifugal force and friction, leading to engine failure. So, how do aircraft bearings ensure the stable operation of the engine?

Aircraft bearings act as a bridge between the rotor and the engine housing, and are mainly composed of three parts: inner ring, outer ring and rolling element. Among them, the inner ring is connected to the rotor, and the outer ring is fixed to the engine housing. The rolling element realizes a smooth transition between the inner and outer rings, ensuring that the rotor can rotate stably around the axis.

Manufacturing high-quality aircraft bearings is a very challenging task. With the continuous improvement of aircraft engine performance requirements, especially in terms of temperature, load, speed, life and reliability, the design and production of aircraft bearings have become more complicated.

On the one hand, aircraft bearings need to meet extremely precise standards. At high speeds, even small dimensional deviations can cause vibrations, affect engine performance or cause failures. Irregularities in rolling element shape can lead to uneven stress distribution, increase the risk of wear and shorten service life. High surface roughness not only increases energy consumption, but also produces fine particles, reduces efficiency and poses a safety hazard.

Therefore, the precision of aviation bearings must be strictly controlled. Taking the F100 engine used in F-15 and F-16 as an example, the shape and size accuracy of its aviation bearings must be maintained at the micron level, the roundness error of the rolling element and raceway must not exceed 1 micron, and the surface finish must be controlled within the range of 0.1 to 0.2 microns.

On the other hand, the extreme working environment places extremely high demands on the selection of materials. Aviation bearings need to withstand huge axial and radial loads and cope with engine vibration and airflow impact. For example, the internal temperature of the F100 engine can reach 1700 degrees Celsius and the pressure can reach 20 standard atmospheres. This means that the materials used to manufacture aviation bearings must have high strength, high temperature resistance, high pressure resistance and fatigue resistance.

At present, aviation bearings used in many advanced fighters mostly use special alloy steels or ceramic materials. For example, Rolls-Royce of the United Kingdom chooses M50 steel to manufacture aviation bearings. This steel exhibits excellent high temperature strength and hardness after heat treatment. Silicon nitride ceramics, with its high hardness, low friction coefficient, excellent corrosion resistance and oxidation resistance, show excellent performance under extreme conditions.

Aviation bearings are one of the important symbols of high-end aviation manufacturing, reflecting the country's technological level in this field. With the application of new materials, design optimization, advancement of manufacturing processes and development of testing technology, aviation bearings in the future will have higher load-bearing capacity, better adaptability, longer service life and higher reliability.