Schaeffler strengthens commitment to rear axle steering

Development cooperation started with Bosch Automotive Steering

Intelligent mechatronic rear axle steering ensures greater driving comfort and safety at 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 worldwide automotive and industrial supplier Schaeffler expands its offer in the field of rear axle steering and joins Robert Bosch Automotive Steering GmbH in the development cooperation. The aim of the cooperation is to offer customers a complete package of rear axle steering systems and thus to open up the market. Schaeffler supplies the mechatronic rear axle steering (iRWS); Bosch Automotive Steering supplies the software and electronics in the form of a Steering Control Unit. "For optimal customer benefit, we combine the strengths of both companies in a single system," says Matthias Zink, Executive Board Automotive OEM at Schaeffler. "For Schaeffler, intelligent rear axle steering is an important milestone on the way to becoming preferred technology partners in the field of chassis systems."

Rear axle steering as mechatronic evolution

Already in the year 2015, Schaeffler, the automotive and industrial supplier, launched and established the mechatronic cheek stabilizer (iARC). "The experience we have gained from this has directly influenced the development of mechatronic rear axle steering," says Dr. Keiwan Kashi, Head of Mechatronic Systems 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 emerged, The mechatronic rear axle steering increases driving comfort as well as safety and can play out its advantages especially in the course of urbanization. In this way, steering in the opposite direction to the front steering reduces the turning circle and increases the manoeuvrability, which for example considerably simplifies the search for parking spaces in the city. In addition, supporting steering movements of the rear axle improve handling during driving, increase vehicle stability and driving comfort, and improve vehicle safety. The rear axle steering of Schaeffler is characterized by the 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 wave drive. This ensures self-restraint and thus ensures that the rear axle steering does not change without the driver's control. In addition, the planetary wave drive guarantees a very high efficiency. The acoustic-optimized design is particularly suitable for use in quiet e-vehicles.

Bosch Steering Control Unit supports safe driving

Bosch controls the Steering Control Unit (Steering Control Unit). This combines controller and electric motor and software in one component. The scalable and modular design of the Steering Control Unit is an important basis in the new rear axle steering system of Schaeffler for numerous driver assistance functions. The use of mechatronic control has already proven to be a million-fold success in the field of front axle steering. Thanks to the Bosch Security concept, the steering is also secured against cyber attacks. Functions and updates are supported by over-the-air technology. "The third generation of Bosch Steering Control Unit has already been successful for front-wheel steering in the market since last year," says Dr. Stefan Waschul, Head of the Robert Bosch Automotive Steering GmbH's product range of car steering systems. "We are bringing this expertise into cooperation for rear-axle steering. As market leader for steering systems, we also contribute our experience and know-how in the fields of software and e/e architecture."

Bosch is already working successfully with this technology in numerous customer applications and has decades of experience in software development and steering control. Based on the steering signal recorded by the torque sensor, the electronic control unit calculates the optimal steering support and controls with this information the electric motor, which provides the required power. The Steering Control Unit does not only calculate the servo support depending on the steering point on the steering wheel, but also takes into account many additional vehicle parameters.