Svenska mekanikdagar 2013

Övrigt konferensbidrag, 2013

Gearbox is an essential element in power transmission. Efficient gearbox means efficient power transmission. Hence lower energy consumption. Losses in the gearbox can be sorted into two; load-dependent and load-independent losses. Load-dependent are related to friction, and load-independent losses are mainly related to lubricant. Load-independent losses are the focus of this paper. An experimental rig (Chalmers gearbox rig) based on the FZG gear test rig was built. The test gears have a slight gap in between the mate teeth and are driven by slave belt and in order to eliminate contact (friction). The idea is to get pure load-independent losses. Flow visualization study was chosen as a first method to study oil flow inside a gearbox. A set of external flash and a camera were used to capture instantaneous splashes in different pitch line velocity and different oil level. Hydrotreated process oil was used due to its transparency. The temperature of the oil was maintained at 40°C to match the viscosity of Castrol Syntrans 75W-85 at 90°C. Understanding the splash behavior are essential in order to understand the flow phenomena and to be able to study the flow further with more advance method, such as computational fluid dynamics (CFD) or particle image velocimetry (PIV).