Rennschmiede Pforzheim – they have their concept


While the Rennschmiede Pforzheim team was previously represented at the Formula Student competition by a combustion-engine vehicle, it will enter an electric race car for the first time in 2020. This not only means a change in design, but also in support from STOBER. While this support was purely financial in the past, the drive specialists now also provide gear units, motors, drive controllers and plenty of know-how. At the end of November, the students invited sponsors and supporters to the college, where they presented the new concept of the RSP20.

The students of Rennschmiede Pforzheim know it will not be easy for them at the upcoming Formula Student Electric (FSE). They have previously celebrated successes on the big racing tracks of the world with vehicles equipped with a combustion engine. "Developing a purely electric race car is certainly new territory for us. We have to completely rework our concept," says Michael Schaffranek to the group of gathered sponsors, friends and supporters invited by the college, Hochschule Pforzheim. Schaffranek studies mechanical engineering and has assumed technical leadership of the mechanics for this season. Making it into the top ranks is not even the goal in in 2020, however. "For now, we want to develop a vehicle that we can even get to the starting line. On this basis, we can then improve throughout the year." The Rennschmiede team relies on familiar technologies and the help of sponsors to build a roadworthy race car. These sponsors include STÖBER Antriebstechnik from Pforzheim. "We have long had an excellent relationship with the college," says Stephan Scholze, Head of Management Center Electronics at STOBER. "In the past, we provided purely financial support as a platinum sponsor of the team. Now, we supply top-quality drive components, and our engineers help the team out with their extensive expertise," adds Dr. Florian Dreher, STOBER's primary contact for matters of geared motors. The drive specialist supplies two high-speed synchronous servo motors, which the aspiring engineers then attach to the rear axle, as well as two compact planetary gear units and two highly dynamic SI6 drive controllers. These units are used in machine tools, for example, or even in pickand-place systems—in other words, wherever movement and positioning have to be extremely fast and precise. And this is a pet project of the Pforzheim specialists. "We actually don't equip vehicles with our solutions," explains Dr. Dreher. For this reason, he and his colleagues from the respective development departments modified the gear units slightly, and the motors and drive controllers a little more—"but did not integrate them," he emphasized. That is ultimately a job to be done by the students. While drive controllers are located in the control cabinet at STOBER customer facilities, in race cars, they must be in a housing that protects them against dirt and moisture. In addition, highefficiency cooling for the geared motors and more power at the controllers are also important.

"The students develop the concepts in close cooperation with STOBER experts, and ultimately implement them on their own," says Dr. Dreher, describing the collaboration. After all, they know exactly what they need—how much torque is necessary at the rear axle, for instance, or where the components must be attached. "It is important that we coordinate the motors and gear units to each other optimally for this purpose," says Schaffranek, explaining one of the design tasks. "On curves, the outer wheel turns faster than the inner wheel. We're still working out how to handle that." In this way, the racing team will make its new race car, which is called RSP20 this season, ready for qualification step by step. Formula Student Germany is a design competition where experts judge the teams in terms of concept, planning and on the vehicle itself. Since all race cars are prototypes, they have to comply with a variety of safety measures and rules. If the teams meet these basic requirements with their cars, they can take part in the race. "They check the battery, the electrical safety, all safety-related components and accessories, and more," says Schaffranek. No operating fluid is allowed to leak and regulations for rollover protection must be met. They must also comply with a certain volume level and pass a brake test. "We want to be able to complete every test successfully with the new RSP20," the future mechanical engineer explains. "Because only then will we also be allowed to drive it." And it will pass the tests—STOBER engineer Stephan Scholze is sure of that. "Some things will surely go wrong in the course of the project, but that is the only way the students will learn. We will be by their side to offer our knowledge at all times." The prototype is to be completed in February 2020.