Active steering

The active steering is a special steering for motor vehicles, wherein the steering ratio between the steering wheel and the wheels can be changed as a function of the driving speed.

The active steering system allows for low and medium speeds ( inter alia when parking ) a large steering angle of the wheels in a relatively small steering wheel. This results in average velocities to a sporty - direct steering when parking to less steering effort. At high speeds, for example on the highway, the steering angle compared to the steering wheel is small, so the steering is indirectly and comfortable. This also provides steering error can be compensated.

At slow speeds, the required steering wheel rotation of a straight line until it stops less than one revolution (300 °). This is only about half of the required steering wheel turns at the usual car steering.

The active steering system consists of a planetary gear and an electric motor before the actual steering gear. The transmission angle of the input shaft (steering wheel ) and the output shaft (pinion ) on the sun gears and planetary gears is done. In the case of the superimposition of the electric motor drives the planet carrier, and thus there is an additional relative movement of the sun gears. This movement leads to the desired superposition or change the steering ratio.

Was developed active steering by ZF Steering Systems GmbH, in cooperation with BMW. It is offered as an option among others, the BMW 5 Series E60/61 since 2003.

The Active Steering received the Innovation Award of German Industry in January 2004.

In the March 2010 published new BMW 5 Series models, the Active Steering was extended: The new system is called Integral Active Steering and steers the rear wheels of the vehicle with accordingly. The steering deflection of the rear wheels shall not exceed 2,5 °.

A competing development with other components is the dynamic steering of Audi, which also comes from the supplier ZF Steering Systems GmbH.