Process modeling of linear coil winding processes with a subsequent deformation model

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The winding of electric drives is a decisive for the its performance and thus has to meet stronger demands regarding its manufacturing. For hybrid electric vehicle applications concentrated windings, also called tooth coils, are state of technology. They are design with a noncircular coil body which is being wound continuously with a copper wire. The major challenge for efficient windings is the layer structure after a defined winding scheme, a flush winding, which results in a high copper fill factor. In order to ensure a proper operability a damage of wire insulation or a reduction of the wire gauge, which would lead to a higher electric resistance, must be prevented. The linear winding process, as a direct winding process, enables a wire sensitive winding with a high productivity. Currently, the process design as well as the achievable coil quality parameters are determined on empiric experimental bases. This is due to the unknown parameter cross-interaction of semi-manufactured goods and the process. In particular, the influence of the wire and its deformation behavior and effects, like a gauge reduction due to strong straining, cold hardening or the spring back behavior while placing the wire onto the coil body, are unknown for the linear winding process. This results in decreased productivity and lower winding quality parameters. The deduced scientific objective is a deformation based process model which interlinks theses different effects in order to determine stress-strain-states of the wire within the production process and the in the final product. The new gained process knowledge will be used as an input model for a new wire oscillation control. With the specific use of deformation effects a better winding result can be achieved as well by optimizing the process frame parameters. Different deformation effects will be investigated by separate experiments and then joined into a consistent material model for insulated copper wire. The link of the different effects during the winding process will be modeled at the place of occurrence using FEM with a demonstrator coil dummy. Of particular interest are the wire load conditions while placing the wire around the coil body edges, the resulting wire behavior and induced fluctuations of the wire tensions. Since most effects cannot be measured within the process, a multi body dynamic simulation will be developed to determine the wire load conditions. This process simulation will be linked with the earlier derived material model in order to include the dependencies of the wire bending torque from the deformation frame conditions.