First rear axle transmission crossbeam made of plastic in the Mercedes-Benz S-Class; 25% weight savings over aluminum
02 July 2015
The first plastic transmission crossbeam in the rear axle subframe has been developed by ContiTech Vibration Control and BASF for the S-Class from Mercedes-Benz. The crossbeam is made from the engineering plastic Ultramid A3WG10 CR, a specialty polyamide from BASF which is particularly reinforced and optimized to withstand high mechanical loads.
Compared to the previous beam made from die-cast aluminum, this highly durable component offers a weight saving of 25%, better acoustics as well as excellent mechanical properties even at high temperatures and conforms to the latest crash requirements. The design expertise of BASF’s simulation tool Ultrasim also made a major contribution to these properties.
The plastic load-bearing structural component meets all the requirements for the static and dynamic loads which act on a transmission beam. As a central component of the rear axle it supports part of the torque which is transferred from the engine to the transmission, and bears a constant share of the load of the differential.
To replace the aluminum in this demanding, crash-relevant application, the plastic has to meet high mechanical requirements. The plastic Ultramid A3WG10 CR (CR = crash-resistant), which is 50% glass fiber reinforced, shows optimum strength and rigidity and displays a low tendency to creep under constant loading. In addition, the material has to withstand high bending torques. The component shows good NVH performance.
BASF used its Ultrasim simulation tool in the early phase of development of the new crossbeam in order to determine the size of the component, optimize the component geometry and predict how the component would behave in injection molding and in operation: The simulation of ultimate loads, strengths under dynamic loading and crash safety reflected the real component behavior very well. ContiTech Vibration Control used Ultrasim’s Integrative Simulation to model the entire manufacturing chain. Thus it was possible to define the component geometry at an early stage and reduce the number of prototypes.
I had not thought we would see plastic for structural components for years, it at all.
Amazing.
Posted by: Davemart | 02 July 2015 at 02:28 PM
Re-enforced plastics (3-D printed?) can already be made to replace complex steel and aluminum components.
Initial cost may be higher but total lifetime cost, due to reduced weight and non-rusting, could be very different.
Future extended range BEVs should take advantage of lower weight re-enforced plastic components and lower drag design to double the range with same batteries?
Posted by: HarveyD | 03 July 2015 at 09:52 AM