Active Steering - BMW System Mechanical Layout

BMW System Mechanical Layout

The BMW active steering system consists principally of a power assisted rack and pinion steering gear, a double planetary gear system in the steering column, and an electric actuating motor.

The double planetary gear system incorporates an input sun gear connected to the driver’s steering wheel, two planetary gears, an output sun gear connected to the steering pinion, and a rotating housing. If the housing is held still, the driver’s steer inputs are translated from the input sun gear, thought the planetary gears (sharing a common lay shaft) to the output sun gear with a net 1:1 ratio. I.e. if the planetary gear housing is held still, conventional steering operation is retained. This characteristic provides a means of steering the vehicle in the event of an active steering system failure.

The planetary gear housing features external gear teeth and can be rotated by a motor and worm gear. Alteration of the housing position allows rotation of the output sun gear independently of the input sun gear position. I.e. if the driver were to hold the steering wheel (and therefore the input sun gear) stationary, driving the planetary gear housing will result in the rotation of the steering pinion (and therefore a steering action at the front wheels). By manipulating the position of the planetary gear housing, the active steering ECU can synthesize a variable steering ratio or generate steering actions independently of the driver.

Read more about this topic:  Active Steering

Famous quotes containing the words system and/or mechanical:

    Few white citizens are acquainted with blacks other than those projected by the media and the so—called educational system, which is nothing more than a system of rewards and punishments based upon one’s ability to pledge loyalty oaths to Anglo culture. The media and the “educational system” are the prime sources of racism in the United States.
    Ishmael Reed (b. 1938)

    The correct rate of speed in innovating changes in long-standing social customs has not yet been determined by even the most expert of the experts. Personally I am beginning to think there is more danger in lagging than in speeding up cultural change to keep pace with mechanical change.
    Mary Barnett Gilson (1877–?)