Determination of Fatigue life of Spiral bevel gears used in automotive differential gearbox

Abstract

This paper describes the experimental destructive testing of spiral bevel gears used in automotive differential gear box. The experimental testing is aimed at early detection of failure of spiral bevel gears during operation by continuously recording and comparing the sound and vibration characteristics during testing. For this purpose, a special fatigue test rig has been developed which can apply dynamic rotational loads with the help of a three phase AC electric motor. The accelerometers located on the drive side (crown pinion) and the slave side (crown wheel) measures the vibration characteristics and an acoustic sensor place near the gears in mesh measures noise levels. The acquired data in time domain are then converted to frequency domain by using a FFT. The signature of failure of pinion was obtained. Three pairs of gears were tested a new gear pair, a used gear pair and a gear pair after breakage of one teeth of pinion. The results obtained show that there is a significant increase in sound and vibration level for used and damaged gear pair. By comparing the results, it is possible for early prediction of point of failure which can be a significant finding in early detection of failure of spiral bevel gears.

Design and Numerical Simulation using Vibration Analysis for the Detection and Reduction of Failures of the Gear Pair of the Differential System of a Powertrain

“…Demonstrating that the previous stresses are directly proportional to the operating torque. Recently, analysis and test results of a differential gearbox of an automobile have been reported [4][5][6]. The authors perform a static and dynamic analysis of various bodies of the Mahindra-Bolero car's differential gearbox assembly, determining the limiting torque at which the gearbox fails.…”