Modeling Geometric Wire Bending Behavior in Needle Winding Processes Using Circular Arcs with Tangential Linear Functions

Abstract

The increasing demand for high-quality yet low-cost electrical machines for electric and hybrid electric vehicles requires optimizing manufacturing processes across all machine elements. The needle winding technology offers the potential to meet these requirements for the production of essential components: copper windings. Thereby, the understanding of wire behavior plays a key role. In particular geometric wire bending behavior significantly influences the planning and execution of winding trajectories. Thus, building on previous work, this paper takes further steps toward a data-driven empirical approach to modeling geometric wire bending behavior. The overarching goal is to provide an efficient and comprehensive model of wire bending geometry as a function of wire tensile force and wire exit angles at the needle outlet. Spline models generated with the help of a purpose-built test bench with a dedicated image processing pipeline serve as the basis for a simplified modeling approach. The proposed model is based on circular arcs with tangential linear functions, allowing the wire bending geometry to be defined with only three parameters. Qualitative analyses of the resulting model behavior and quantitative investigations of the model errors show accurate approximation results and confirm the suitability of the developed method.