A Practical Method for Measuring Rolling Element Load Distribution of Rolling Bearings Using a Fiber Optical Sensor (2nd Report, Dynamic Measurement)

Abstract

An external load applied to a rolling bearing is distributed among the rolling elements. The conventional calculation of load distribution among rolling elements already established assumes that the bearing races, shaft and housing are rigid except for elastic deformations at the individual contacts between rolling elements and raceways. In many applications, the bearing rings as well as the supporting structures can not be considered rigid, so that the actual load distribution is different from that predicted on the above assumption. Several experimental methods to determine the load distribution of rolling bearings have been proposed so far. Their methods, however, can not provide dynamic load distributions while rolling elements make one revolution along the raceway. The objective of this study is to establish a more direct method than the other ones for determining rolling element load distributions not only statically but also dynamically. In the method herein proposed, the strains of rollers developed under an applied load are measured by using an optical fiber strain sensor mounted on a roller of a measuring cylindrical roller bearing. The obtained strain data provides rolling element load distributions. This paper presents the method for determination of dynamic load distributions, and shows examples of dynamic measurements using the method. The dynamic behaviors of the load distributions and the correspondence of the experimental results to the conventional theory have been investigated. In addition, the comparison of the dynamic load distributions obtained here and the static ones presented in Part I of this study has been made.