Influence factors on gearbox power loss

Purpose - Besides other approaches, fuel savings in automotive applications and energy savings, in general, also require high-efficiency gearboxes. Different approaches are shown regarding how to further improve gearbox efficiency. This paper aims to address these issues. Design/methodology/approach - The paper takes the following approach: theoretical and experimental investigations of bearing arrangements and gear design as well as lubricant type and lubricant supply to the components lead to efficiency optimisation. Findings - No-load losses can be reduced, especially at low temperatures and part-load conditions when using low-viscosity oils with a high viscosity index and low oil immersion depth or low spray oil supply of the components. Bearing systems can be optimised when using more efficient systems than cross-loading arrangements with high preload. Low-loss gears can contribute substantially to load-dependent power loss reduction in the gear mesh. Low-friction oils are available for further reduction of gear and bearing mesh losses. All in all, a reduction of the gearbox losses in an average of 50 per cent is technically feasible. Originality/value - Results from different projects of the authors and from the literature are combined to quantitatively evaluate the potential of power loss reduction in gearboxes.