Compared to internal combustion vehicles, battery-powered cars are much simpler. There’s no oil to change, no multi-gear transmission that can go wrong if you don’t take care of it, and all the mechanical parts usually take up less space.
That’s why we get frunks, a flat floor, and generous trunks on most EVs. But things might be even better in the packaging department, as Korean automakers Hyundai and Kia found out.
Meet the Universal Wheel Drive System (or Uni Wheel for short), which was designed to make room for more stuff under an EV’s body–batteries (which can lead to more range), storage space, or just to have a more airy cabin.
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The compact yet complicated unit integrates a single sun gear that transfers power through a pair of pinion gear arms that can move independently to an outer ring gear in a flexible planetary design. With this approach, there’s no need for a conventional constant velocity (CV) axle to transfer power from the electric motor to the wheel because the input shaft of the Uni Wheel can move up/down and left/right without huge losses in efficiency.
With CV axles out of the picture and a set of redesigned electric motors that are more compact on hand, the drivetrain is simpler and takes up less space on the chassis. Hyundai and Kia say that the system–which is still in its infancy–offers improved ride quality, greater durability, and increased efficiency in addition to better packaging options compared to the current way of doing things.
The Uni Wheel also incorporates the reduction gear that’s usually found next to the electric motor in today’s conventional EVs, which allows for the motor housing to be smaller.
Here’s how Hyundai and Kia describe their creation:
A conventional drive system using a regular CV joint suffers from a decrease in efficiency and durability as the angle of drive shaft deflection increases when traveling over bumpy, undulating surfaces. Uni Wheel can transmit power with almost no change to efficiency regardless of wheel movement, ensuring high durability and ride comfort.
When combined with electronic air suspension that can adjust ride height according to the driving situation, this can be increased to stabilize the vehicle on rough roads or decreased for high-speed driving to improve power and stability.
It’s a pretty interesting concept that’s different from an in-wheel motor which adds even more complexity to the mix. It’s also not the first time Hyundai has shown a concept that might make life easier for future EV drivers, with its Mobis division showcasing the so-called e-Corner System that enables 360-degree turns.
Thoughts? Let us know in the comments below.
