Device and method for measuring thickness variation of large roller element bearing rings

The thickness variation of a large bearing ring is an important measure effecting on the rotational accuracy and partly defining the dynamic properties of the bearing. For example, when a bearing inner ring is installed on a rotor shaft, the final roundness profile of the installed bearing inner ring is the sum of the roundness profile of the rotor shaft roundness and the thickness variations of the inner ring and the possible conical adapter sleeve. In the present study, a device and a method for measuring the thickness variation of large roller element bearing rings was presented. To enhance the measurement quality, each measurement consisted of 20 rounds of measurement data, which were averaged in the frequency domain after the Fast Fourier Transform. In addition, the quality of the measurement was analysed by comparisons with existing devices, coordinate measurement machine (CMM) and roundness measurement machine, and by repeatability measurements. In the analysis, both thickness variation profiles and their harmonic components were investigated. The results show, that the overall agreements with the CMM and the roundness measurement machine were satisfying and good respectively. The repeatability of the proposed device was similar to the roundness measurement machine. According to the results, the device and the method were considered to be valid and deserve further interest and investigation for the bearing ring measurements.