Pitting detection in worm gearboxes with vibration analysis

• Three escalators gearboxes were diagnosed for pitting failure.
• Vibration analysis was used for pitting detection.
• Three algorithms were employed for signal analysis, including statistical metrics, Spectral Kurtosis and envelop analysis.
• We find the pitting detection is depending on measurement direction.

Diagnostics of worm gear defects with vibration analysis is challenging and this is reflected in the limited number of publications. However, these gears are commonly used in many applications such as escalators, mills, and conveyors, and significant cost may arise from their down time due to unidentified defects. This paper aims to apply various vibration analysis techniques to diagnose the presence of naturally developed faults within worm gearboxes.The condition of three different worm gearboxes were assessed using various vibration signal analysis techniques including a few statistical measures, Spectral Kurtosis and enveloping. This was undertaken in an attempt to identify the presence of defects within the worm gearboxes. It is shown that irrespective of the predominantly sliding motion of the gears, diagnosis of faults is feasible as long as the appropriate analysis technique is employed. In addition the results show sensitivity to the direction of vibration measurement.