Contactless Air-Bag Firing and Signal Transmission on the Steering Wheel with an Inductive Contact Unit

The electrical connection between chassis and steering wheel which is used for igniting and monitoring the driver's airbag and also for transmitting horn and other signals today takes the form of a galvanic contact - in other words, an electrically conductive connection. In virtually every case multiple elastic contacts resembling clock springs are used but very occasionally slip rings are still used. Contactless electrical connection would present a wide range of benefits here and would not cost any more. In the case of an AC airbag firing system the usual capacitative coupling would be replaced by the new inductive system.

The use of a magnetic compound material means virtually lossless transmission up to higher transmission frequencies and a comparatively simple manufacturing process. The very first prototype is a system which carries out all essential functions on the rotating part of the steering wheel without the use of electronic elements and which is still predominantly analogue in character. A brief treatment is given of the concept of integrated digital transmission systems on which we are already working.