Numerical and Experimental Analysis of the Transmission Error in Hybrid Metal-Composite Gears

• Numerical analysis of hybrid metal-composite gear meshing by using an analytical-FE gear contact model. • Experimental analysis of the Static Transmission Error in hybrid gears under different operating conditions. • Experimental evaluation of the impact of the manufacturing process on the meshing behaviour of transmissions with hybrid gears. The aim of this work is to provide a numerical analysis and an experimental characterization of the meshing behaviour of hybrid metal-composite gears, manufactured by press-fitting a carbon fibre reinforced polymer (CFRP) web into a steel gear structure. Hybrid gears have been recently proposed as an answer to the quest for lighter mechanical transmissions, with improved meshing performance in comparison to conventional lightweight gears. Numerical and experimental studies at single-gear level as well as gear-pair testing demonstrated a huge potential for such a technology to contribute to system-level weight reduction. In this paper, the meshing behaviour of a hybrid gear, manufactured by interference fitting and engaging with a conventional steel gear, is analysed numerically by using a hybrid gear contact model that combines, in a multibody simulation environment, an analytical description of the non-linear contact phenomena with a Finite Element (FE) formulation of the overall gear compliance. An experimental characterization of the Static Transmission Error (STE) is also given by using a high-precision gear test-rig, where quasi-static tests have been carried out under different load conditions. Important indications on how the manufacturing process must be implemented to prevent from poor meshing performance are illustrated.