Investigation of the influence of material anisotropy on teeth excitation

• Applicants: Professor Dr.-Ing. Welf-Guntram Drossel; Professor Dr.-Ing. Berthold Schlecht
• Subject Area: Engineering Design, Machine Elements, Product Development ; Acoustics ; Mechanical Properties of Metallic Materials and their Microstructural Origins ; Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 273223221

The acoustic optimization has a large priority for gear manufacturers. Because of environmental constraints and comfort requirements it is necessary to observe limiting values. Especially for gear units with lightweight construction a differentiated optimization is required. To realize that an important approach is the reduction of the gear mesh excitation using new manufacturing technologies, which lead to better load capacities and ideal properties of materials and components. For this purpose the effects caused by the manufacturing of the toothings will be investigated in detail in this project, whereas the focus will be on analysing generative laser beam melting and rolling of toothings. The rolling of toothings with involute profile has reached a level of development, which allows the use of these toothings in power transmissions. In terms of the influence of the manufacturing bibliographical references and own investigations show, that rolled toothings have higher bending and fatigue strengths compared to cutted toothings. In contrast to that there is almost no published knowledge about the acoustic behaviour of toothings produced by rolling. Just one publication by the Technical University of Munich, published in the 1960s, describes that the gear mesh excitation depends in addition to other cause variables significantly on the fibre structure of the gear wheel and the surface quality of the tooth flanks. Furthermore in relevant technical literatures there are general propositions about the topic of a better smoothness, which are not proved reliably. For this reason they provide an opportunity of profound research issues. The involved research unit 2 has already experiences in terms of the generative manufacturing of toothings emerged from a current DFG project, which deals with the production of gear wheels using 16MnCr5 powder to integrate cooling channels into the wheel's structure. Additionally this manufacturing method offers a great potential for special geometries of the gear wheel, which are relevant for acoustic and lightweight reasons. The focus of this project is the scientific verification of a better acoustic behaviour caused by property modifications of rolled or generative produced toothings compared to gear wheels manufactured by cutting based on the same geometry. As part of the project the evidence of the property modification should be provided by intensive fundamental research. The cause-effect relationships have to be recognized in a macroscopic and microscopic level of the material properties and should be integrated in an calculation model. This model is supposed to predict the gear mesh excitation in consideration of the different material properties.

• DFG Programme: Research Grants