Publication Details
Abstract
Differentials are vital and delicate pieces of equipment in the automotive power-transmission group, and unnoticed damage or malfunction in the crown wheel and pinion will lead to expensive downtime and even, in the worst possible scenario, dangerous failures. Vibration analysis is a widely accepted and non-destructive method of identifying such faults in autos. The paper describes an experimental study on the vibration behavior of an auto differential in five conditions healthy, with a damaged pinion tooth, with a fractured pinion tooth, damaged crown wheel tooth, and broken crown wheel tooth in two states of operation at the input speeds of the pinion of 2000 and 3000 rpm. A special stand was created and included the differential itself, an electric engine with belt-and-pulley drive, a speed regulator, vibration insulators, and a piezoelectric accelerometer connected with the data-acquisition system.The theoretical gear-meshing frequencies (GMF) of the pinion’s crown wheel and of their harmony were gained through the use of gear geometry and revolution rate values compared to the experimental results achieved through measurements. The outcomes show that the vibration intensity follows a linear relationship with the increasing intensity of the fault (healthy < worn < broken) in both gears, that the vibration caused by a broken tooth happens in the form of sudden pulses and can be measured in figures, that additional harmonics of GMF are introduced and increase with the accumulation of defect severity in the crown wheel, and that the separation of the symptoms of defects from the background level increases due to the increase of rotational speed of 2000–3000 rpm. This observation makes it possible to better understand the behavior of a differential’s vibration signal, and thus create the basis for a future automated fault classification.