Design improvement for rear axle cover

Abstract

In this thesis, leakages on the rear axle covers used in Ford vehicles are investigated. Main reasons of leakage are discussed and problem is solved by improving rear axle cover design and by improving cover bolt performance. To simulate the real road condition of the vehicle, vehicle durability test and comparison oriented beam fatigue tests are performed with the current rear axle cover designs. Modifications on the bolt hole locations in the cover, thickness and cover flange lenght are the proposals for improvement. Several FE analyses were performed for each proposal. The results of the analyses were compared with the vehicle and beam fatigue test results, which were performed during cover improvement studies. Beside cover design improvement studies, load tests, torque vs. angle test and bolt elongation studies were performed in order to reveal the effects of the parameters on cover bolt performance, such as paint on the surface of the cover in contact with the bolt, sealer, sealer process and torque. Static analyses with static and equivalent dynamic loads considering the condition of the maximum vehicle gross weight effect on the rear axle and the maximum torque transferred from propeller shaft to the rear axle, were performed using finite element software. The results of the analysis were compared with the results of the tests.