In a bid to transform the landscape of electric vehicles (EVs), Korean automakers Hyundai and Kia have unveiled their groundbreaking Universal Wheel Drive System named 'Uni Wheel.'
(Photo : Hyundai Motor Group)
What if we take the CV joint, drive shaft, and reducer and move them all into the wheel?
Introducing Uni Wheel
Uni Wheel is taking a fresh perspective on the internal architecture of EVs, cleverly repositioning key drive system components into the previously untapped space within the wheel hub.
Interesting Engineering reported that this inventive approach not only boosts the overall efficiency of the vehicle but also unlocks a considerable amount of internal space, signaling a noteworthy departure from traditional drive system configurations.
The companies highlighted that the system liberates significantly more interior space compared to conventional drive systems, paving the way for future mobility products optimized for various applications, including Purpose Built Vehicles (PBVs).
The unveiling of this technology took place during the Uni Wheel Tech Day hosted by the brand in Seoul on November 29. Kia and Hyundai Motor have taken significant steps by filing and securing eight patents related to the design and technology of Uni Wheel in South Korea, the United States, and Europe.
Departing from Conventional Method
The Uni Wheel design represents a departure from the conventional method of transferring power from the engine to the wheels, commonly seen in internal combustion engine (ICE) vehicles that utilize drive shafts and constant velocity (CV) joints.
In the context of electric vehicles, where the engine and gearbox are replaced by a motor and reduction gear, the Uni Wheel maintains consistency in the final gearbox mechanism, which transmits power to the wheels.
Distinguished by a unique planetary gear arrangement, Electrek reported that the Uni Wheel features a central sun gear flanked by four pinion gears on each side, all enclosed by an encircling ring gear.
The motor-driven power engages the sun gear, initiating a synchronized rotation with the pinion gears, ultimately driving the encircling ring gear and, consequently, the wheel. According to the automakers, this synchronized motion facilitates the forward propulsion of the vehicle.
In contrast to conventional drive systems with standard CV joints that experience efficiency and durability reduction on uneven surfaces due to increased drive shaft deflection angles, Uni Wheel maintains nearly constant efficiency, irrespective of wheel movement.
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Uni Wheel's advancements play a pivotal role in optimizing passenger space, addressing a common challenge faced by traditional electric vehicles (EVs) that often compromise space due to the placement of low batteries necessitating elevated ride heights.
This takes a strategic approach to battery packaging, minimizing any encroachment on passenger space. This attribute holds significant value, particularly in the context of Personal Battery Vehicles (PBVs), where a flat-floor design is imperative for maximizing interior space.
As indicated on their joint press release, Kia and Hyundai Motor are actively engaged in the testing phase for Uni Wheel, focusing on ensuring stability, efficiency, and durability.
These ongoing tests are geared towards refining its development, with a commitment to further enhance efficiency through adjustments to the reduction gear ratio and upgrades to the lubrication and cooling system.
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