Investigation of harmful slip in a rolling bearing using a thermographic camera with a derotator

Abstract

Due to their high availability and versatility, rolling bearings are a standard solution for mounting and support of rotating components. The service life of an entire rotating machine is often limited by the service life of rolling bearings. This can be shorter than expected if the rolling bearing is operated in harmful operating conditions, e.g. in the presence of slip. Slip means that there is a deviation between the theoretical angular velocity of the rolling element set and the actual angular velocity. In this context, slip is harmful if it leads to increased friction and thus heating of the bearing. The occurrence and properties of slip are not completely understood yet. Therefore, it is of interest to investigate a relationship between slip and heating of the rolling bearing in order to better understand damages of the rolling bearing. In this work, a method is presented in which, in addition to slip measurements with a high-speed camera, a thermal imaging camera is used to investigate the heating of the bearing during operation. Since the rotational movement and exposure time of the camera would cause motion blur, the thermal imaging camera is operated together with a derotator to optically eliminate the rotational movement. The investigations of the rolling bearing are carried out under different operating conditions (different loads and rotational speeds), which have an influence on the slip behavior of the bearing. Thus, the potential of this investigation method for deepening the understanding of heating and friction in rolling bearings is demonstrated.