Influencing factors on rotor overmold designs for robustness against media and thermal shocks

Overmolding magnet rings to achieve a BLDCC rotor has the potential to form cost-effective and reliable rotor assemblies, that are able to withstand harsh environments. Due to the different nature of materials used, integrity over life of the assembly may become an issue if not all influencing factors are considered within the design. With the example of a Nd-Fe-B plastic bonded magnet ring in aggressive media, this contribution sheds light on various mechanisms affecting the endurance performance of an overmold of a ring magnet as well as some possible processes to support the design phase of the rotor.