Ford, Schaeffler demo advanced wheel hub drive

April 16, 2013 // By Christoph Hammerschmidt
In tomorrow's city cars, electric wheel hub drives will be the solution of choice - they enable innovative, extremely flexible and versatile design solutions. Carmaker Ford and mechatronics company Schaeffler AG have developed such a drive and integrated it into a concept vehicle based on a Ford Fiesta.

The E-Wheel Drive, as they called their development, contains all functional elements associated to generating thrust, deceleration, and safety. Electric motor, power electronics along with the associated control unit, brake and cooling system are all integrated into the wheel hub. Unlike the normal Fiesta, the concept vehicles is equipped with a rear wheel drive.

Fig. 1: Wheel hub drives offer remarkable design freedom. For full resolution click here .

Each motor in the test vehicle provides 40kW of peak power or 33 kW of continuous output. Thus, the vehicle disposes of a total engine power comparable to a vehicle with a conventional 110 hp / 90 hp engine. The liquid-cooled electric motor is currently available in its second design iteration and has reached beta status, offering a remarkable torque of up to 700 Nm. In comparison to the first design version shown in 2010 in an Opel Corsa, this is an increase of 33 % more power and 75% more torque. The motor is supplied from a high voltage battery with 360 to 420 volts. The wheel hub drive is relatively heavy: Compared to a normal wheel with brake and wheel bearing, the hub drive weighs 45 kilograms more; the total weight is 53 kilograms. The entire drive has a volume of 16 litres which makes it possible to integrate it into a standard 16" rim. While the current design version adds another 6 kg compared to its predecessor, the engineers were able to reduce the vehicle's total weight since the cooling system as well as the power electronics along with the control unit could been integrated into the wheel, which made complex wiring redundant.

The current vehicle serves as experimental platform. "Wheel hub drives can unfold their strengths only in new, innovative vehicle concepts", said Schaeffler executive manager Peter Gutzmer at the presentation of the vehicle during the congress of a car magazine. "A highly integrated wheel hub drive