Coextrusion Head Segmentation for Tire Insert Geometry

The extrusion head is segmented into multiple independent flow channels (first flow channel for underlayer mixture, second flow channel for tread mixture, third flow channel for electrically conductive mixture). Each channel operates independently with its own pressure control, allowing the insert to be extruded at lower pressure through a dedicated channel rather than forcing high-rigidity material through the underlayer and tread channels which would require excessively high pressure.

The profiling blade is designed with a localized electrically conductive mixture application zone at its tip. This allows the third electrically conductive rubber compound to be applied only where needed (at the interface between underlayer and tread) rather than throughout the entire extrusion process, enabling precise control of insert geometry and reducing the pressure required for insertion.

The extrusion head includes a dedicated third flow channel specifically for the electrically conductive mixture, separate from the channels for underlayer and tread mixtures. This segmentation ensures that the insert material is delivered through a controlled, dedicated pathway with consistent geometry, preventing random variations in insert cross-section that would occur if material had to pass through the variable geometry of the other flow channels.

The profiling blade acts as an intermediary device that receives the electrically conductive mixture from the third flow channel and precisely positions it at the interface between underlayer and tread. The blade's geometry controls the exact shape and position of the insert, ensuring consistency along the profile length while simplifying the overall extrusion head structure compared to using a complex nozzle system.

The electrically conductive mixture is applied locally at the precise interface between the underlayer and tread through the tip of the profiling blade, rather than being extruded through the entire width of the flow channels. This localized application ensures that the insert width is exactly what is needed for electrical conductivity without excessive width, and maintains consistent cross-section along the profile length.

The third flow channel for electrically conductive mixture is segmented into multiple smaller sub-channels or openings at its outlet, positioned at the underlayer-tread interface. This segmentation allows precise control of the insert width and distribution, ensuring adequate electrical conductivity while minimizing unnecessary insert width and eliminating random cross-section variations.