The aim of this study is to develop a thermal modeling of a grease lubricated rolling bearing in order to analyze the heat evacuated through its solid parts and the lubricant. The system under consideration in this study is a clutch thrust bearing and more precisely a sealed single row angular contact ball bearing. To analyze heat transfer inside the bearing, two models have been developed using the thermal network method. These models have been compared to measurements performed on a specific test rig. As some heat transfers appear to be negligible, in the end a simplified model is proposed.

In order to use electric motors which run up to 40,000 rpm in future automotive applications, this study aims to experimentally investigate if splash lubrication technique is worth considering for high-speed gears, i.e., for tangential gear speed up to 60 m/s. To this end, a specific test rig has been used to operate a single spur or helical gear in various operating conditions (lubricant, oil sump volume, temperature, etc.). Churning loss is measured and, as the fraction of air in the lubricant (namely, oil aeration) can be influential on this source of dissipation, a specific sensor is also employed for online monitoring of oil sump aeration. By inserting some moveable walls in the gearbox, it is demonstrated that churning losses and oil aeration can be significantly reduced by mounting these flanges at an appropriate distance to the gear lateral faces. Based on dimensional analysis, an engineering criterion is proposed to properly choose the clearance between the tested gear and the flanges.