Development cooperation started with Bosch Automotive Steering
Intelligent mechatronic rear-axle steering ensures more driving comfort and safety with the highest energy efficiency
Matthias Zink: "An important milestone on the way to becoming an innovative technology partner in the field of chassis systems"

The global automotive and industrial supplier Schaeffler is expanding its range in the rear axle steering area and is entering into a development cooperation with Robert Bosch Automotive Steering GmbH. The aim of the cooperation is to offer customers a complete package for rear axle steering systems and thus to open up the market. Schaeffler supplies the mechatronic rear axle steering (iRWS); Bosch Automotive Steering provides the software and electronics in the form of a Steering Control Unit. “For optimal customer benefit, we combine the strengths of both companies in one overall system,” says Matthias Zink, Board Member Automotive OEM at Schaeffler. "For Schaeffler, intelligent rear-axle steering is an important milestone on the way to becoming the preferred technology partner in the field of chassis systems."

Rear axle steering as a mechatronic evolution

The automotive and industrial supplier Schaeffler launched the mechatronic roll stabilizer (iARC) back in 2015 and established it there. “The experience we have gained in the process flowed directly into the development of the mechatronic rear axle steering,” says Dr. Keiwan Kashi, Head of Mechatronic Systems Business Unit at Schaeffler:
"By combining our mechatronic know-how with our core competence in the industrialization of mechanical and mechatronic components, a highly efficient product has been created that we can adapt individually to customer requirements." Urbanization showing its advantages. Steering in the opposite direction to the front steering reduces the turning circle and increases maneuverability - which, for example, considerably simplifies the search for a parking space in the city. In addition, supporting steering movements of the rear axle improve handling while driving, increase vehicle stability and driving comfort, and improve vehicle safety. The rear axle steering from Schaeffler is characterized by its low system weight of up to eight kilograms, which is made possible by the targeted use of lightweight construction technologies. The core element of the system is a planetary screw drive. This ensures the so-called “self-locking behavior” and thus ensures that the rear-axle steering does not adjust without a control command from the driver. In addition, the planetary screw drive guarantees a very high level of efficiency. The acoustically optimized design proves itself particularly when used in quiet electric vehicles.

Steering Control Unit from Bosch supports safe driving

Bosch contributes the so-called Steering Control Unit to the system. This combines the control unit and electric motor and software in one component. The scalable and modular design of the Steering Control Unit is an important basis in Schaeffler's new rear-axle steering system for numerous driver assistance functions. The use of mechatronic control has already proven itself a million times over in the area of front axle steering. Thanks to the Bosch security concept, the steering is also protected against cyber attacks. Functions and updates are supported by means of "over-the-air" technology. "The third generation of the Steering Control Unit from Bosch has been successfully on the market for front axle steering since last year," says Dr. Stefan Waschul, Head of the Car Steering Systems division at Robert Bosch Automotive Steering GmbH. “We bring this expertise into the cooperation for the rear axle steering. As the market leader for steering systems, we also contribute our experience and know-how in the areas of software and E / E architecture. "

Bosch is already working successfully with this technology in numerous customer applications and has impressed customers with decades of experience in software development and steering control. On the basis of the steering signal recorded by the torque sensor, the electronic control unit calculates the optimum steering assistance and uses this information to regulate the electric motor, which provides the required power. In the Steering Control Unit, the power assistance is not only calculated depending on the steering torque at the steering wheel, but many additional vehicle parameters are also taken into account.