Schaeffler rear-wheel steering system goes into series production; planetary roller gear

Schaeffler has begun series production of a new mechatronic rear-wheel steering system, bringing enhanced agility on bends and superior inner-city maneuverability to the new electric SUV of a well-known vehicle manufacturer.

By adding steering functionality to the rear axle, Schaeffler’s new technology improves handling in city traffic, enhances lane-change stability, and makes the vehicle easier to park.

The key to Schaeffler’s new rear-wheel steering system is the planetary roller gear—a first based on precision mechanical engineering from the company’s in-house industrial technology operations. The result is a highly compact system that is lightweight, quiet in operation, and optimized for easy vehicle integration.

Planetary roller gear: The technology innovation that sets the Schaeffler rear-wheel steering system apart from the rest. Photo: Schaeffler (SevenM)

Additional vehicle models featuring the steering system by Schaeffler are due to go into production before the end of 2023 as well as in 2024.

Schaeffler’s rear-wheel steering system consists of two subassemblies. The first—and the key to it all—is a precision mechanical system featuring a planetary roller gear from the company’s Industrial division that has been specifically adapted for automotive applications. The second is the powerpack, comprising the electronics, electric motor, and software. Schaeffler develops the overall system and takes care of its integration into the customer’s vehicles.

The planetary roller gear sets the Schaeffler system apart from rear-wheel steering systems made by other manufacturers, which traditionally use trapezoidal screw drives. Consequently, the Schaeffler product not only meets the stringent safety standards of Automotive Safety Integrity Level D (ASIL D), but it also yields significantly increased efficiency, reduced friction, and shorter system reaction times.

The system is especially advantageous for drivers of electric vehicles because it compensates for the downsides of the longer wheelbase necessitated by the underfloor battery position common in such vehicles. A longer wheelbase means a larger turning radius and hence reduced maneuverability.