- Fiber-reinforced composite leaf spring based on the polyurethane matrix resin
- Completely new rear axle concept
- Weight saving of 4.5 kg
Already a permanent feature of automotive engineering, lightweight construction methods continue to steadily gain in importance. Due to automation and cycle time issues, however, manufacturing composite components under mass-production conditions is a major challenge. Now a fiber-reinforced composite leaf spring based on the polyurethane matrix resin Loctite MAX 2 from Henkel is being used in the chassis of the new Volvo XC90, a crossover SUV of which the new rear axle concept is to serve as a platform for other model series. Benteler-SGL is aiming to produce several hundred thousand of these leaf springs per year.
Low viscosity material allows shorter cycle times during RTM
Henkel has contributed its process know-how in RTM (resin transfer molding) to further optimize the cycle times in the manufacture of the fiber-reinforced leaf springs. Due to its low viscosity, the polyurethane matrix resin Loctite MAX 2 rapidly fills the mold and quickly yet gently impregnates the fiber material, resulting in short injection times. With the curing rate also faster than that of epoxy resins, overall cycle times are shorter.
Innovative rear axle concept
The suspension of the new Volvo XC90 features a transverse fiber-reinforced composite leaf spring instead of the usual array of coil springs. This gives rise to a highly compact design as well as producing a weight saving of some 4.5 kilograms compared to a conventional coils spring concept. Further functional benefits arise from a smoother ride and improved NVH (noise, vibration, harshness) behavior. The trunk volume is also increased because there are no suspension turrets. Volvo operates on the basis of what is called the “Scalable Platform Architecture” (SPA) principle, according to which certain successfully implemented concepts are flexibly adapted for application to further vehicle models. The new rear axle is destined to be incorporated into additional automobile models in the near future.
“The example of our leaf spring for Volvo Cars demonstrates that fiber composite mass production is today already a reality. What’s more, with this flexible component design, we are able to cover an entire platform with a relatively small number of spring variants.” says Frank Fetscher, Head of Business Development at Benteler-SGL Automotive Composites.