Hyundai and Kia have reinvented the wheel again. The Uni Wheel concept will revolutionize the layout of electric vehicles and significantly increase the useful space. And not just cars, the system can work in wheels ranging from 4 to 25 inches.
There is something a bit inefficient about the way almost every electric vehicle’s powerplant is currently designed, ArsTechnica reports. And it’s not about the battery in the middle – it makes sense for weight distribution until batteries that will be part of the body structure become available. The problem is in the electric vehicle drive train, a bulky device that contains an electric motor, some gears, and usually power electronics.
One of the concepts is to install an electric motor directly into the wheel. However, there are also problems here – the unsprung weight increases (the lighter the wheel, the better), and the engine receives the same loads, shocks and jolts as the wheel, and therefore breaks down much faster.
Uni Wheel is designed a little differently. The wheel has its own electric motor, but it is mounted much closer to the suspension, which frees up more space between the wheels (which can be used for more battery modules, or to increase the luggage compartment). Until now, the problem was that conventional equal angular velocity joints could not handle the angles that would be required given the shorter drive shaft from motor to wheel.
Therefore, instead, the joint, driveshaft and gearbox were moved to a new unit mounted in the wheel. It contains a planetary gear system that transmits drive from the engine to the wheel, but with a multi-link arrangement between the gears, which allows the drive shaft to move in a wide range, repeating the movements of the suspension.
Not limited to passenger electric vehicles, Hyundai and Kia say that Uni Wheel can enable a wheelchair or multi-wheeled robot to climb stairs “as smoothly as an escalator.”
Like many other strange engineering ideas, the Uni Wheel is still at an early stage of development, so there are no guarantees that it will go into mass production in the near future. But both automakers are enthusiastic.