Innovative Torsional Vibration Reduction Devices - Vehicle-Related Design and Component Strength Analysis

Downsizing and downspeeding are currently important development approaches of the automobile industry to improve fuel efficiency and to reduce emissions. Decreased operational speeds in combination with higher combustion pressures lead to an increase of the excitation of torsional vibrations by the combustion engine. Torsional vibrations in powertrains can cause strength and NVH problems as well as lower driving comfort and reliability of the vehicle. Currently, conventional systems for reduction of torsional vibrations are increasingly reaching their limits. In cooperation with several institutes of the Technische Universität München (TUM) innovative concepts for an improved reduction of torsional vibrations in automotive powertrains have been developed. Several of those concepts have been realized as prototype assemblies engineered by the Gear Research Centre (FZG). ([6], [7], [8], [12], [13], [14]) During the design process, different challenges with regard to mass, mass moment of inertia and space demands have to be considered to ensure system performance and to meet vehicle-related requirements. Demands of prototype assemblies regarding modularity and installation interfaces to the available testing environment have to be considered as well. The demanding, partially atypical and dynamic mechanical loads of the components require both analytical and FEA-based strength analysis attending to the design process of the prototype assembly. With regard to bearings and gears with oscillating load, several steps of design and strength analysis have to be performed. Selected systems are presented in concept with special regard to their prototype designs. Selected design steps and performed strength calculations for major components used in the developed torsional vibration reduction devices are introduced.