Kia and Hyundai have unveiled the Universal Wheel Drive System — called ‘Uni Wheel’ —which they promise will revolutionise the design of electric vehicles by incorporating gears into the wheel hubs.
It is said to dramatically improve the space available inside an electric vehicle by moving the main drive system components inside the wheel hub.
In EVs, the engine and transmission are replaced by a motor and reduction gear, but the final method of transmission to the wheels is the same, using drive shafts.
Uni Wheel opens new possibilities and enables a flat-floor configuration by moving an EV’s reduction gear inside the wheel hub, locating a compact individual motor close to each wheel, reducing the length of the drive shafts.
The system frees up significantly more interior space compared with conventional drive systems.
“We are pleased to showcase innovative ideas that could become game changers in the future mobility market,” said Jongsool Park, Senior Fellow at the Institute of Advanced Technology Development of Hyundai Motor Group. “We will perfect the technology so that customers can experience mobility in a completely different and new way.”
Uni Wheel uses a special planetary gear configuration consisting of a sun gear in the centre, four pinion gears on each side and a ring gear surrounding this arrangement. Power generated by the motor is transmitted to the sun gear, which in turn engages the pinion gears to rotate the ring gear. This is connected to the wheel to drive the vehicle.