Enhancement of flank load-carrying capacity of oil-lubricated plastic gears

• Applicant: Professor Dr.-Ing. Karsten Stahl
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 560225405

To date, only limited knowledge is available on the achievable tooth flank load capacity for helical plastic gears. In relevant calculation methods for determining the tooth flank load capacity, such as VDI 2736, the influence of the helix angle has not yet been sufficiently taken into account. The aim of theoretical and experimental investigations is to derive findings on the load-carrying capacity of helical and sliding speed-optimized plastic gears. Furthermore, geometry influences on the tooth flank load capacity that have not been taken into account so far are to be integrated into common analytical calculation methods. The microstructures present on the gear surface and in the material depth have a significant influence on the achievable pitting load capacity of thermoplastic gears. In the proposed research project, optimal microstructures in terms of load-carrying capacity will be identified. In the future, this is to enable the optimum utilization of the potential carrying capacity of the material during the manufacturing process by means of targeted temperature control during the injection molding process. Due to the large number of thermoplastic gear materials available on the market, the generalizability of the findings obtained is of particular importance. The aim of the work is to derive generally valid statements on carrying capacity behavior that can be transferred to different materials, based on the results of the previous project and the expected results. In addition to the investigation of the carrying capacity, the main focus is on the statistical lifetime behavior. The consideration of previously neglected influences in the calculation of helical gears picks up on the carrying capacity potential of helical-toothed plastic test gears and, like an optimization of the microstructure, contributes to a further increase in carrying capacity. Overall, the performance range of thermoplastic gears is thus further increased and a safe and economical gear design is made possible.

• DFG Programme: Research Grants