Study on measurement of three dimensional ball motion and running performance in rolling contact ball bearing under extremely high speed conditions

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The angular contact ball bearings are frequently adopted as the bearing for the spindle of the machine tools. In recent years, these bearings used in machine tools such as machining centers have been required to operate under extremely high speed and heavy load conditions. In order to make clear the causes of heat generation, friction loss and tribo-failures such as smearing in high speed ball bearings, it is indispensable to grasp the contact conditions between ball and races or between ball and separator, and the development of measuring method of the actual ball motion has been desired. Using a magnetized ball and hall elements arranged on the fixed oblique coordinates, the authors tried to measure the behaviour of the ball motion in the angular contact ball bearing 7209A. The results were compared with those of the conventional method with a moving orthogonal coordinate system. Furthermore, the ball motions in the angular contact ball bearing under combined radial and axial loads were also measured. The results obtained are summarized as follows.1.It was confirmed that the measured values such as the rotational speed of the ball and the separator almost agree by two different methods and it was recognized that the prepositional method is practical use and useful.2.Especially, it was recognized that the rotating speed of ball extremely decreased under high speed and light load conditions.3.The ball motion of the angular contact ball bearing is affected by the combined load, and this tendency became remarkably with increase in the shaft speed.4.Furthermore, it was recognized that the load distribution obtained by the numerical analysis has a close relation to the ball motion.