Localized damages such as spalls, dents and raised metal may develop on bearing raceways and roller bodies in operation for various reasons. They can excite bearings and adjacent mechanical structures into vibration. By measuring machine vibration, it is possible to detect potential bearing damage. However, to do so, it is critical to understand the bearing vibration characteristics that are excited by localized damages.
The vibration of a TRB (tapered roller bearing) excited by a localized damage on a rotating cone (inner ring) raceway was studied using a three-dimensional, non-linear vibration model. Bearing vibration responses were analyzed in three directions. The responses exhibited multiple BPFI (ball passing frequency, inner) harmonics. The spectral envelope is determined by the bearing’s dynamic properties. The vibration characteristics in the axial direction were discovered to be different from those in the radial directions. The reason behind that is revealed in this paper.