Comparative Study of Techniques Used for Gearbox Diagnosis

The aim of this paper is to present two widely used techniques in gearbox diagnostics through implementation of these techniques on a heavy duty truck with two types of local faults, broken teeth and defected bearing. The first technique presented in this study is the stationary STSF (Spatial Transformation of Sound Field) which is based on the measured acoustic signal captured in the nearfield of the operating gearbox. The second technique is the Vibroacoustic technique which is based on the vibration signal picked up on the gearbox surface. The results from acoustic signals were compared with vibration signals. In contrast to Vibroacoustic technique, unless special methods and particular arrangement are used to reconstruct the acoustic field, STSF may suffer from some difficulty and limitations. Also, background noise or any acquisition errors may result in an erroneous reconstruction of the acoustic quantities.