Investigation of the ball-bearing temperature rise under an oil-air lubrication system

Ball-bearings are widely used on many high-speed rotating systems. However, heat generation and dynamic loading caused by high-speed operation have been the limiting factors for increasing the speed limit of many high-speed ball-bearing applications. Therefore, providing proper lubrication and preload to reduce heat generation effectively is a major task for high-speed ball-bearings. Recently, oil-air lubrication has been used on high-speed ball-bearings because of precise oil quantity control and high cooling efficiency. However, the fluctuation in oil supply resulting from the periodic oil feeding is unfavourable. In this study, equipment for measuring the fluctuation in the oil supply was established. The operation parameters affecting the stability of the oil supply for an oil-air lubrication system were experimentally studied. A test rig for high-speed ball-bearings was also developed. Tests were conducted to study the effects of the preload, oil quantity, air flowrate and rotating speed on the bearing temperature rise. The operating conditions that provide a stable oil supply and low bearing temperature rise were established.