Some Studies On Bearing Clearance And Unbalance Response Prediction Of Rotor Bearing System

Abstract

newline Rolling element bearings are extensively used in many high-speed types of machinery such as gas and steam turbines, pumps, high-speed compressors, generators etc. Reliable prediction of faults in such machineries is a challenging and important task in the modern industries. Even a very small fault in rolling element bearing significantly affects the performance of the rotor-bearing system. The fault in rolling element bearings if not detected in time can cause tragic failures of the machineries supported by these bearings. The operating parameters like variations in the machinery speed, unbalance, operating load, bearing clearance, damages to the structural elements, viz., inner race, outer race, rollers, cage, etc., can cause a bearing to vibrate at higher energy levels and consequently will accelerate its wear. Therefore it is important to identify these faults to minimize the vibration levels, which affects the system performance drastically. Also it is observed that rotating machineries used in modern industries are designed for high speeds, tight tolerances and high reliability to transmit maximum power under different working conditions. To design such a system detailed dynamic analysis in the design stage is necessary to maximize the life of the equipment and to improve its overall performance. The rotor-bearing system of modern machineries is complex and needs a reliable and accurate prediction of change in its dynamic characteristics. The fault diagnosis and detection plays an extensively important role in the design of high-speed machinery. The performance of any rotating machine depends to a large extent on the smooth and quiet running of rolling bearings. Overall dynamic behavior of any such machine is directly affected by vibrations characteristics of bearings used in it. Rolling bearing in any machine is a major source of vibrations due to varying compliance, time varying contact forces, radial clearance, and bearing defects.