Cooperation with SonoMotors

04.12.2020

Munich / Neustadt an der Weinstraße
December 4, 2020

Cooperation with SonoMotors

The Sion on the road: collaboration with Team Rosberg Engineering

Today we are pleased to announce the closer cooperation between SonoMotors and TRE.

For the innovative vehicle development Sion, TRE is the partner for chassis development from concept to SOP. TRE is also responsible for manufacturing the chassis prototypes (axle modules). This collaboration demonstrates that TRE is a competent partner for up-and-coming carmakers, especially in innovative vehicle projects such as the Sion, due to its “out of one hand philosophy”. In collaboration with our colleagues at SonoMotors, we have written a blog article describing details of the development collaboration.

Whether we like it or not, millions of people drive cars in Germany every day. According to a 2017 study by the Infas survey institute, the car is by far the most popular mode of transport. So it’s no surprise that of the 3.2 billion kilometers traveled in this country every day, around 60 percent are done in our beloved passenger car.

What exactly happens inside the vehicle while we maneuver it precisely through the traffic jams of the big city and across the country’s expressways fades into the background – at least if you’re not an automotive enthusiast. In this context, the chassis, and thus also the steering of a car, is a central aspect, especially as far as the driving experience is concerned. Just think of the worlds that lie between a car with and without power steering.

Our partner for suspensions: TRE

When it came to selecting a suitable axle concept, we already teamed up with a professional from the world of motorsport in 2018: Team Rosberg Engineering, or TRE for short. The company, headquartered in Neustadt an der Weinstraße, traces its roots back to its namesake racing driver and Formula 1 world champion Keke Rosberg.

In the late 1990s, Rosberg took the approach of incorporating expertise from motorsport into the development of production vehicles. His idea: a development center for chassis systems that benefits from the expertise of racing engineers and is thus also of use to mainstream car manufacturers. Today TRE is one of the leading companies in the field of chassis development.

TRE’s corporate headquarters in Neustadt an der Weinstraße in Rhineland-Palatinate.

Managing Director Eckardt Doehrer describes the company’s vision in an interview as follows: “TRE has made it its goal to offer customers all development steps from white sheet of paper to prototype from a single source, if desired. For the collaboration with Sono Motors, we are developing the entire suspension and chassis system for series vehicle and prototype.”

From computer model to finished axis

Computer work is indispensable for the development of vehicle parts. With the help of CAD models, engineers design the various components and assemble them. Many different factors have to be taken into account. “TRE’s scope is divided into the areas of design, simulation and production,” explains Axel Hoffmann, Head of Chassis Development. “In the design team, making the best possible use of the available installation space, the chassis is laid out and the new components are designed.”

The CAD models are checked and adjusted again and again.

The development of the so-called subframe is particularly exciting. The engineers are developing this in such a way as to ensure high lateral stiffness and a high degree of deformability of the frame in the event of a frontal crash. These two goals must be combined with the special installation space requirements of an electric drive.

CAD model of Electronic Drive Unit and subframe.

The positioning of all components of the chassis is carried out in close cooperation with the multi-body simulation team. The developers also evaluate the kinematic parameters and their influence on the design. The steering system of the Sion in particular was analyzed extensively by TRE, since the requirements for steering wheel position, pedal free travel, joint angle and kinematics have to be met in a confined space.

An ADAMS model of the front chassis.

The computer simulations also already include components from potential suppliers so that the desired overall vehicle behavior can be achieved. This allows engineers to include the vehicle’s requirements – lateral, longitudinal and vertical dynamics, comfort, sufficient ground clearance, a tight turning circle – in their calculations and implement them.

The developers also simulate various loading conditions, on the one hand to test elastic compliance and on the other to test the vehicle’s ground clearance. The results are displayed in a corresponding CAD model for all participants.

Simulation of different load conditions on the CAD model.

For the new prototype, some parts had to be manufactured by hand based on the chassis development for the series. In June this year, TRE began to derive the design of the entire chassis for the prototypes based on the CAD model for the production vehicles at that time.

Welding work on the subframe.

“We have designed more efficient prototype manufacturing processes for parts such as subframes, wheel carriers, stabilizer bars and composite control arms, which are mass-produced in high volumes using expensive tooling,” explains Axel Hoffmann. “The properties and functions of the prototype parts designed in this way already largely correspond to those in the production vehicle – despite the fact that no production tools are used. This means the vehicles can be used for tuning runs and road tests.”

The computer model of the front axle of the new prototype.

Of course, there will still be differences in detail to the series. The prototypes are secured with predominantly quasi-static load cases. These parts are further optimized in terms of component mass and service life for the final series application. The tools used to manufacture the series axles will also be different, as large quantities have to be produced in contrast to prototype production.

The single wheel module and the finished front axle module.

In October, the ready-to-install axle modules were transported to Roding. There, they have already been installed in the prototypes and tested for their function. We have already shared some photos of the production at Roding with you. If you haven’t seen them yet, you can do so here.

The big picture in view

TRE is a really important partner for us. We are very happy to have the concentrated expertise of this team on our side. With Nico Rosberg, TRE shareholder and Formula 1 world champion, the team is also backed by a sustainable entrepreneur and investor. Nico was enthusiastic about the Sion and Sono Motors and shares our goal of driving positive change for society and the environment: “As a sustainability entrepreneur, I am particularly keen to contribute our expertise to the development of the Sion by Sono Motors and to further develop the future of alternative mobility concepts.”

As far as the project is concerned, we agree wholeheartedly with TRE CEO Eckardt Döhrer when he says: “We are delighted to be able to contribute our in-depth know-how and TRE’s more than 20 years of experience in chassis development at Sono Motors to the development of the Sion, thereby helping to shape technological progress in future-oriented mobility concepts.” With partners like these, our ambitious goals can be achieved!

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