Ultrasonic Measurement of Load of Rolling Element Based on the Influence of Contact Deformation on Ultrasonic Propagation

The measurement of rolling element load helps to judge bearing useful service life. At present, the load of rolling element is mainly estimated by strain gauge. However, this method usually destroys the structure of the bearing. The measurement results cannot reflect rolling element load of real bearings. In this article, a novel ultrasonic method is proposed to measure the load of rolling element. First, the influence of outer raceway’s deformation on ultrasonic propagation path of a planar probe is analyzed with a ray approach. Then, the peak width induced by contact deformation is used as a new ultrasonic indicator to measure the rolling element load, which has fewer application limitations than the previous ultrasonic methods. Further, the relationship between the rolling element load and ultrasonic peak width is established. Finally, the theoretical model was verified by both finite element simulation and experiments without oil lubricated. The measurement results with oil lubricated in the real field showed that the maximum measurement error is 12.3%, compared with the ROMAX quasi-statics simulation results. Nondestructive sensor installation and convenient data acquisition make it possible to apply the presented method in actual industrial field.