ERJ staff report (BC)
Geneva, Switzerland – Fiat has adopted an integrated jounce bumper system on its Punto car that integrates several components into one to deliver better performance and a lower system cost, reported DuPont at a pre-K show press briefing in Geneva on 13 June.
Part of a vehicle’s shock absorber system, the jounce bumper is designed to absorb impact and dampen noise, vibration and harshness (NVH) by preventing the metal shock absorber spring from fully compacting during shock impacts due to potholes, curb and objects in the road. It also augments the spring function to improve vehicle behaviour when negotiating smaller holes in the road surface, cobblestones, or during rapid direction changes or sudden braking. Patrick Cazuc, automotive director Europe for DuPont Performance Polymers, said the jounce bumper was subject to “a high degree of solicitation” in service. He explained to ERJ that this referred to rapidly varying loading forces.
The component is the result of an integrated design, materials and processing approach by DuPont, Fiat, Insit, and Ossberger. The design, using DuPont’s Hytrel thermoplastic polyester elastomer, eliminates the need for metal or reinforced polyamide saturation cups and acetal or rubber rings normally used to increase energy absorption.
The design obviates the need for metal or reinforced polyamide saturation cups and acetal or rubber rings normally used to increase energy absorption.
Using the TPE instead of foam polyurethane (PUR) or rubber derivatives is claimed to deliver high elastic recovery, excellent fatigue and durability, and little variation in stiffness over a wide range of temperatures. Cazuc added: “Materials are critical in component design and the best results happen when the three primary phases in product development – design, materials and processing – converge.”
The jounce bumper will be featured at the K2013 trade show from 16-23 October in Düsseldorf, at the DuPont exhibit in Hall 06, stand C43.