Optimization of Wheel Hub Gasket and Cap Design to Prevent Grease Contamination and Bearing Failures

摘要

Wheel end bearing is one of the critical components of the vehicle as it directly faces the road loads for harsh operating environment. Bearing being a precisely manufactured component and rotating at high speed, utmost care is required while assembling as well as during operation. In operating condition wheel end is directly exposed to outside environment making it prone to entry of contamination. This contamination if not prevented from entering into wheel end through proper sealing it would cause lubricant contamination and consequently bearing failure. Bearing replacement and overall wheel end service is time consuming activity reducing the turn out time of the vehicle. In wheel ends, one side is sealed with the help of seal while the other side is protected by cap and gasket. This cap-gasket interface is very critical from sealing perspective and utmost importance needs to be taken while designing the same. This paper focuses on the various aspects of design to be considered while designing gasket and caps for the sealing of wheel hubs. Additionally CAE analysis methodology is adopted to virtually find the effects of different gasket and hub cap parameters on sealing. Hub cap and gasket together forms a wheel end sealing. In wheel ends, a gasket is mounted on wheel hub face and cap is bolted on to it. When the bolt is tightened, tightening force gets transferred from hub cap to gasket and generates compression. This compression makes the joint leak proof. Different design parameters like cap thickness, bolt preload are studied to find out the performance of the gasket joint. Pressure compression curve of gasket is used for studying the behavior of gasket at different cap thickness. For virtual analysis sealing performance of gasket and cap is evaluated by doing nonlinear analysis of gasket joint. ANSYS workbench is used as a finite element analysis tool to simulate wheel hub gasket performance. Some additional steps are used in this analysis besides other conventional nonlinear analysis in ANSYS. CAE results are then finally evaluated by physical fitment of parts on vehicles and measurement is done accordingly. Footprints of gaskethub cap is taken on physical vehicle and compared with virtual footprints. Also contamination studied on periodic intervals between new and old designs to analyze the results