Samenvatting

Environmental protection plays an important role today. The automobile industry in particular is constantly criticized when it comes to pollutant emissions. Not only the automotive industry, but also the automotive suppliers are committed to deliver more energy efficient solutions. The rolling bearing industry in particular is committed to contribute towards a reduction of CO2 emission by improving the efficiency rate of vehicle drive lines. SKF has launched a special Environmental Vehicle program (ENVI), dedicated to the development of energy efficient solutions. Part of the program is the development of a variable preload system for bearing units to reduce friction losses. The actuator for this project is developed in a previous stage at SKF Automotive Development Centre. The next stage, that is considered in this report is to investigate the influences and potential benefits of applying such a system on a bearing unit. Additionally, the system is optimized to meet the highest friction reduction feasible with acceptable bearing life and stiffness. The Hybrid Pinion Unit, developed by SKF for a rear axle differential is used as a case study.