Cologne – BOGE Elastmetall GmbH, a global provider of vibration technology and plastics applications for the automotive industry, in close cooperation with the LANXESS High Performance Materials (HPM) business unit, have jointly developed the first all-plastic brake pedal, designed for use in electric vehicles (EV).
The plastic pedal owes its high mechanical strength and low weight to a thermoplastic composite design. Its structure comprises an insert made from Tepex dynalite, a continuous-fiber-reinforced thermoplastic composite from LANXESS, and several tapes.
“The composite structure makes the brake pedal 50-percent lighter than a comparable steel design,” explains Dr. Klaus Vonberg, an expert in lightweight design at HPM’s Tepex Automotive Group. “The structural component meets the demanding load requirements thanks to the tailor-made fiber-layer construction of the Tepex insert and additional local tape reinforcement. Extensive automation allows the geometrically complex safety-critical component to be manufactured efficiently and in a way that is suitable for large-scale production,”
The fully consolidated semi-finished products Tepex dynalite have a thermoplastic matrix that is typically reinforced with layers of continuous glass-fiber fabric. The brake pedal for the battery-electric sports car uses a composite structure with a polyamide 6 matrix, which contains unidirectional fiber layers inside and fabric layers with fibers arranged at 45° angles on the two covering layers. The inner layers are what give the component its excellent tensile and bending strength.
Tapes are thin plastic strips with unidirectionally oriented, high-strength continuous fiber systems embedded in the thermoplastic matrix. Multiple tapes with glass-fiber rovings are used in the brake pedal to reinforce the bottomside of the component. Since the tapes and the Tepex insert consist of mutually compatible plastic matrices, the tapes can simply be welded onto the Tepex insert using a laser. This results in tailor-made laminates with fiber layers that follow the load paths precisely and are adapted to the exact load-specific component requirements. The covering layers of the insert with their 45° fiber layers, combined with the tapes on top, thereby ensure the high torsional strength of the pedal.
“This tailor-made fiber-layer structure and the combination of organic sheets and tapes have made it possible to reduce brake pedal weight even further while simultaneously achieving the exceptionally high level of mechanical characteristics that such a safety-critical component needs to provide,” said Dr. Daniel Häffelin from the Innovation Center at BOGE Elastmetall.
There are currently four different brake pedal designs in mass production based on an all-plastic version. For all component versions, the load paths are also optimized to suit the various torsion directions.
The LANXESS release can be viewed by clicking HERE.