A one-piece injection-molded clip-on feature for a vehicle air extractor has proven a lightweight, cost effective option to improving the quality of air inside the cabin while reducing ingress of noise into the vehicle. Developed and molded by Wegu Manufacturing Inc. (Whitby, ON), the part won the chassis/hardware award the 42nd Annual Society of Plastics Engineers (SPE) Automotive Innovation Awards Competition.
The mechanism acts as a one-way pneumatic valve, allowing air to exhaust, but reducing the amount of noise that can re-enter through the extractor. Already deployed in the 2012 model Ford Escape and Ford Edge, the solution can be applied to any vehicle using an air extractor, including heavy equipment and transport trucks
The "Dual Rate" mechanism is molded as a flat one-piece component in a single shot mold incorporating living hinges and plastic torsional springs for flap motion are integrally molded. "The mechanism is molded in an open position which provides the torsion bars with preload once installed onto the air extractor," explains Naithan Loach, Sales and Engineering Manager at Wegu.
Further, the living hinge design and gating permitted Wegu to bypass conventional wisdom that requires the living hinge be made of 100% virgin polypropylene and qualify the design using a much stiffer and thus lighter 40% talc filled polypropylene.
The original design, which utilizes a steel spring, required proximity sensors and a vision system to damage-protect the tool. The plastic spring design, however, is pre-sprung without the use of any slides, tooling inserts or secondary spring loading methods. A weight saving of 200g/vehicle was thereby achieved. Elimination of all steel components also makes the part 100% thermoplastic, and therefore easy to recycle. The grade was supplied by Rhetech, Inc. (Whitmore Lake, MI).