During the “Uni Wheel Tech Day” in Seoul, Korea, the Hyundai Motor Company and Kia Corporation presented their new Universal Wheel Drive System, or “Uni Wheel.” This innovative approach to electric vehicle drivetrain aims to revolutionize the design of future mobility devices.
The Uni Wheel integrates the major drive system components inside the wheel hub, freeing up interior space in the vehicle. This results in a new drive system framework and allows for the development of mobility goods tailored for various uses, including purpose-built vehicles (PBVs).
In traditional internal combustion engine vehicles, drive shafts and constant velocity (CV) joints transfer power from the engine to the transmission and, ultimately, the wheels. For an EV, the engine and gearbox are replaced with a motor and reduction gear, but the power transmission mechanism to the wheels remains the same.
Compared to traditional drive systems, the Uni-Wheel frees up a large amount of interior space, allowing for the development of mobility goods in the future that are tailored for various uses, including purpose-built vehicles (PBVs).
Jongsool Park, Senior Fellow at Hyundai’s Institute of Advanced Technology Development, said, “We are pleased to showcase innovative ideas that could become game changers in the future mobility market. We will refine the technology to give customers a unique mobility experience.”
With the Uni Wheel system, Hyundai has adopted a similar but distinct strategy. It uses a unique planetary gear layout with a sun gear at the center, four pinion gears on each side, and a ring gear covering everything. The motor’s power is transferred to the sun gear, which rotates the ring gear by engaging the pinion gears. This is linked to the steering wheel and propels the vehicle. The pinion gears on Uni Wheels form two linkages, and this multi-link mechanism allows for a wide range of suspension flexibility through Uni Wheels’s multi-axis movement.
To optimize Uni Wheel’s development, Hyundai and Kia are constantly testing its stability, efficiency, and durability. They also plan to keep working to increase Uni Wheel’s efficiency by changing the reduction gear ratio and improving the cooling and lubrication systems.
In addition to the U.S. and Europe, the automakers have applied for and registered eight patents pertaining to Uni Wheel in South Korea.