STUDY OF AIR INCLUSION IN LUBRICATION SYSTEM OF CVT GEARBOX TRANSMISSION WITH BIPHASIC CFD SIMULATION

The study of the lubrication in gearboxes is an important issue in the design of off-road machines because their reliability depends mostly on the lubrication performance, as well as the machine's lifetime and overall energy efficiency of the transmission is strongly dependent on the lubrication system behavior: In fact the role of the lubrication system is twofold: firstly to remove the heat generated in the highly loaded rolling bearings and the gears found in the power and accessory gearboxes via heat exchangers; secondly to lubricate these parts. The trend in the development of gearbox transmissions has been towards lower consumption and higher power transmitted, consequently it is necessary to conceive more effective and efficient lubrication systems. Nonetheless the lubrication problem often relies on a trial and error approach and most available scientific literature is based on lumped element model dynamic simulation or one phase thermo-fluid dynamic simulations, overlooking the effects linked to cavitation and air inclusion.