How to do high temperature resistant materials and lubrication of the engine bearing - bearing knowledge

After the invention of the plane, the plane has increasingly become indispensable to modern civilization. As we all know, the aircraft engine is one of the most important parts of an aircraft, aircraft engine bearing by burning after the high temperature of the gas turbine, gas turbine driven by a shaft. In the complex structure of engine, engine bearing is the most important thing in this structure, the core of the structure. Can say, the entire structure of the engine, are to be carried out under the drive of bearing work; Bearing, therefore, is to determine the engine performance of a 'brain', for its manufacturing process is also the most exquisite. Of the many properties, heat resistance, is the first heavy engine. If a motor bearing can't afford to severe friction caused by high temperature under high speed rotation, again the strong load capacity and the degree of lubrication, all is lost. In a Russian engine, Russia is casting type, and the United States USES is welded. Domestic is subject to material science and reason of structural mechanics, and there is no solution to the problem of high temperature resistant. First of all, we learn about the aircraft engine operating conditions: 1, high speed. General aircraft engine speed above 18000 r/min, the material requirements of such a high speed is high. 2, high temperature. Engine operating temperature is very high, the operating temperature of the bearing may reach 300 ℃, bearing materials need to be tolerated high temperature. 3, high reliability. Both civil aircraft and fighter jets are very high to the requirement of reliability, juggle is human life. Know the operation condition of the bearing, you can choose to adapt to the working condition of bearing, due to the bearing operating temperature is very high, outer ring USES the AISI M50 material with good resistance to high temperature and high temperature stability, the material at 300 ℃ C still can reach 58 HRC hardness. When high-speed operation, due to the bearing inner ring is rotational, centrifugal force is very large, bearing inner ring cross section subject to cyclic tensile stress, so the inner ring surface can't have any micro crack, to avoid crack propagation under tensile stress, and therefore often USES AISI M50NiL material for inner ring. Because the speed is very high, in order to reduce the additional load caused by the centrifugal force of steel ball, generally use the lighter quality, hardness higher ceramic material, such as ammoniation silicon ( 文中介绍) Or titanium carbide ( TiC) Materials such as steel, sometimes in order to increase the wear resistance of the bearing inner and outer circle and reduce friction, in - Spraying ceramic outer ring raceway. Engine temperature more than 300 ℃ C ah, up to more than 1500 C, how to bearing temperature 300 ℃ C, this is the lubrication system of the credit, in fact there is also a main bearing lubrication system function is the cooling effect. To launch the main bearing as an example, the main bearing is one of the key components of aircraft engine. Under the condition of high speed, high temperature, complex loading operation, main bearing quality and performance directly affect the engine performance, life and reliability. The aircraft engine is one of the key indicators of high reliability. To guarantee the reliability, one of the premise is to ensure that the bearings have a long life - within the engine Main bearing, the life of a military aircraft engine requirements in 3000 hours, commercial aircraft engine is more demanding, to reach tens of thousands of hours. In aircraft engine bearing working environment can use 'purgatory' to describe, they should not only with tens of thousands of RPM speed high speed for a long time, even under various forms of extrusion stress, friction and ultra high temperature. In fact, the high speed turbine in order to reduce the friction with the floating bearing commonly, can only transfer torque, friction to a minimum, angular contact bearings are only used for other moment under axial thrust is mainly composed of thrust bearing. Engine blade is mainly composed of composite material, not too big compressor blade requirements. Lubrication of the engine shaft and the airway. Gas turbine blades and guide blade in the middle of the airway, blade surface laser with holes, useful when working on the blade surface formation gas film separated by high temperature gas. In order to increase the service life of the engine performance and, in the development of high temperature alloy, the manufacturing process plays a great boost to the development of alloy. Due to the emergence of vacuum smelting technology, metal removal of harmful impurities and gas in the accurate control of alloy composition, in particular, the high temperature alloy to improve performance. Subsequently, the directional solidification and single crystal growth, powder metallurgy, mechanical alloying, ceramic cores, ceramic filter, such as isothermal forging new technology research is successful, promoted the rapid development of high temperature alloy. The directional solidification technology is the most prominent, the use of directional technology make directional solidification and single crystal alloy, its temperature is close to 90% of initial melting point. Therefore, the current world advanced aircraft engine blades are manufactured orientation, single crystal alloy turbine blade. From the point of international scope, has formed the equiaxial crystal nickel-based casting high temperature alloy, directional solidification system column crystal and single crystal alloy. High temperature alloy powder from the first generation of 650 ℃ to 750 ℃, 850 ℃ powder turbine disc and double performance powder plate, used for advanced high performance engines. Bearing manufacturing, not only need to material science, mechanics and powerful technology. Also need a lot of objective conditions, for example, must have the appropriate raw materials and excellent metal smelting capacity. Not only that, the experimental process of engine is not flat, require a lot of money, as well as excellent talents and equipment to undertake various types of test, this kind of put a lot of research for a country, can also cause a heavy burden.