A study on axle gear whine noise reduction with deflection test

Abstract

Hypoid gears are used in rear drive and four-wheel drive (4WD) vehicle axles. For this reason, hypoid gear whine noise has long been recognized as a problem, but there have been few or no studies of problem-solving techniques or procedures. This study analysed the possible causes of hypoid gear whine noise for its reduction and investigated the data that should be considered for the optimal shape design of hypoid gears in axle-based vehicles and the procedures for using the data for optimization. For these purposes, a hot deflection test was performed, using an actual gear mounting and the temperature of a cast-aluminium axle housing, with completely processed gear. This test covered the operating range of gear loads, from ‘no load’ to ‘peak load’. Under peak load conditions, the contact pattern extended to the tooth boundaries without showing a concentration at any point on the tooth surface. The transmission error was tested on an axle assembly triaxial real car load and at the correct temperature condition of the axle housing.