In this paper, the models for different power loss sources in transmissions from literature are applied and compared, which form the two methods - ISO 14179-2 and the joint model to estimate the power losses in a transmission. A 2-speed transmission in an electric vehicle is used as a case study to compare the two methods and validate them with experimental data.

In recent years the estimation of gearbox power loss is attracting more interest — especially in the wind turbine and automotive gearbox industry — but also in industrial gearboxes where heat dissipation is a consideration as well. As new transmissions concepts are being researched to meet both ecological and commercial demands, a quick and reliable estimation of overall efficiency becomes inevitable in designing the optimal gearbox.

This paper is intended to enlarge the application range of radial cylindrical roller bearings by means of a more precise determination of thrust load capacity and more cost-effective design.