Consistently on the trail of mobility trends

REHAU researches polymer load-bearing stuctures for electromobility

Polymer specialist REHAU is consistently committed to the areas of alternative drive concepts, new approaches to mobility and lightweight construction. As innovators, we are a valued development partner to all of the well-known national and international automotive suppliers – and even the bicycle industry will value the know-how from REHAU in the future. This is because, for some time, REHAU has been committed to the “load bearing structures for single and multi-track vehicles” research project promoted by the German federal ministry of economics and energy, which started in October 2012. In focus: new types of construction methods for functionally integrating, light and aesthetic supporting frame structures made of polymer materials. Project partners REHAU, bicycle OEM Storck Bicycle and the Institute for Lightweight Construction and Plastics Technology (ILK) of Dresden technical university are currently halfway there – all the production and test phases should be completed by the middle of 2015. Under the project title “Thermobility”, thermoplastic fibre composites are being used.

“Lightweight construction is an important issue for REHAU,” emphasises Alexander Oelschlegel, Head of Corporate Research and Development for Advanced Technologies at REHAU. “The development of a functionally integrating frame for high-quality e-bikes is just one aspect of this. We can learn a lot from the development phase, gaining knowledge about stability and material properties, which we transfer into the other areas.”

Alexander Oelschlegel likes to compare the project approach with the product evolution of bumpers, coming from the classic “bumper bar” (tube) into which a huge diversity of functions has been integrated over the decades. “Our objective is to produce an industrially manufactured product for the mobility of tomorrow, which combines high functional integration with a high standard of quality.”

In the development of the black technology demonstrator, REHAU consistently relies on the advantages of injection moulding. Two half-shells are injection moulded and put together in a load-bearing structure. This must be created such that it can support the loads occurring and both sides remain permanently bonded together. “In the second half of the project, our objective is to develop a structure with the most comprehensive possible functional integration for an e-bike and thus to identify the advantages of the injection moulding process over established metal structures,” says Alexander Oelschlegel. He emphasises that the greatest challenge probably lies in mastering the technical requirements whilst remaining profitable. “We want to develop a load-bearing structure into which the drive, battery, engine control, displays, USB socket, charging cable, light, lock etc. can be completely integrated” – integrated into a new type of flat design.

“Naturally, there were initially a few sceptics about this project approach. There is a lot to consider in practice with respect to material selection, joining process and stability. However, experience from the first 18 months of the project has made us very confident!” The response to the first mobile technology demonstrator, “tb one”, taught Alexander Oelschlegel’s team that the Thermobility project is a very emotive subject, which people like to discuss. “Everyone brings individual personal experience,” the project manager describes with a broad smile. “Many employees have already put the “tb one” prototype through its paces.” This is borne out by the trails on the carpet in REHAU’s Strontium office building in the upper Franconian town of Rehau.

If the “tb two” currently in development proves itself then the OEMs will also benefit: the bicycle frame, which would be “made in Europe”, will impress with short supply chains and high functional integration. Alexander Oelschlegel uses few words to say in a nutshell what motivates the REHAU team: “ultimately being competitive – and setting new standards with respect to design and functional integration.”

Alexander Oelschlegel 
REHAU Head of Corporate Research and Development for Advanced Technologies, Rehau location
Head of Corporate Process Engineering for Pipes/Mouldings