Misalignment effect on gearbox failure: An experimental study

Abstract

Overhang-meshing gears, deflection of pinion/gear shaft, bearing wear, assembly error, poor adjustment of bearings and foundation are the reasons of misalignment in gear drives.In the present work, the misalignment effect on gearbox failure is investigated experimentally using vibration analysis. Misalignment between motor and gearbox is measured using laser alignment system (LAS). The effect of input shaft speed and load on the gearbox failure is also discussed.The misalignment effect primarily observes on the gearbox drive end taper roller bearing and distresses gear transmission. Physical and microscopic examinations of the dismantle gearbox confirm similar findings as observe from vibration spectrum. Severe damages in taper roller bearing (32206) and multiple pits on all the rollers and cone. The bearing cage is deformed badly due to overload and misalignment. The effect of bearing failure on gear’s damage is also investigated. Non-uniform contact patch is observed on the meshing gears in the plane of action. Misalignment results in scuffing failure on the pinion addendum and gear dedendum regions due to limited lubricant in the overstress region. At the end of the test, all the four seals appears safe, while the coupling spiders damage seriously.