Offering commercial-vehicle manufacturers products that improve comfort and safety, while also reducing weight and maintaining durability, is a solid business strategy, particularly in the current climate where even minute gains in fuel efficiency are pursued. At this September’s International Motor Show (IAA) in Hanover, Germany, ContiTech plans to showcase several such products, including one developed by its Air Spring Systems business unit.
The development? Truck air springs with an “innovative” plastic piston that fully utilizes interior volume for enhanced comfort.
“To achieve a completely usable inner volume, we had to implement a so-called two-piece design in combination with a reliable welding technology,” Diethelm Bauch, Vice President of Air Springs for Commercial Vehicle OEMs at ContiTech Air Spring Systems, explained to SAE Magazines via email. This completely usable inner volume is what makes the technology unique.
“In the past, it was only common to use plastic pistons without or only with partial inner volume. Therefore, the usage was limited to applications with minor demand for comfort,” Bauch continued. “With the new two-piece design, it is now possible to gain the maximum comfort level, which could only be realized with heavier steel pistons so far.”
ContiTech claims that up to 75% of the weight of conventional steel pistons is saved thanks to the use of plastic and a new simulation method. The end result is a potential weight reduction of up to 12 kg (27 lb) per axle.
“The plastic material consists of a special kind of reinforced polyamide 6.6 which provides a tight material specification as well as a complete material database necessary for accurate simulation of the molding process and component strength,” Bauch explained. “The achievement of maximum weight saving in full reflection of the given load specification formed one of the major targets of this development project.”
The safety factor stems from the notion that a more relaxed driver—due to improved ride comfort—is a less fatigued and more alert driver.
Air spring systems equipped with the new plastic piston are “basically suitable for all kind of commercial-vehicle rear axles (and load classes),” he shared.
Start of production for the new air spring system was in October 2011 for the serial demands of “a major European truck builder” (see image for perhaps a clue). The development was carried out in close cooperation with the customer and took about five years, according to Bauch.
ContiTech also worked closely with supplier partners to achieve the development goals, he noted, including the producer of the tooling, as well as with the raw material supplier for the specific fiber-reinforced polyamide resin. He would not disclose the identity of the subsuppliers.