Hyundai Motor and sister-company Kia have introduced a groundbreaking innovation for EVs. Dubbed the Universal Wheel Drive System, or ‘Uni Wheel’, the system promises to transform the design of future EVs due its novel approach to EV drive systems.
The Uni Wheel is an integrated wheel drive system that essentially relocates the key drivetrain components such as the driveshafts, CV joints, transmission and differential/reduction gears within the wheel hub itself, thus freeing up space between the wheels both at the front and rear.
Additionally, by replacing the large drive motor with four-smaller motors that sit closer to the wheels, the Uni Wheels creates a flat-floor configuration, freeing up substantial interior space.
This design innovation allows for the development of what the company calls Purpose Built Vehicles (PBVs) and other mobility products optimized for various applications.
Also read: Hyundai-Kia files trademark for Hypercasting - Korea alternative to Tesla's Gigacasting
The Uni Wheel incorporates a special planetary gear configuration that enables multi-axis movement. This unique design, featuring a sun gear, pinion gears, and a ring gear, allows for a wide range of suspension articulation.
Power generated by the motor is transmitted to the sun gear, which in turn engages the pinion gears to rotate the ring gear that is connected to the wheels itself.
An innovation in itself, is the pinion gear assembly, which are connected to each other to form two linkages, and this multi-link mechanism enables Uni Wheel’s multi-axis movement to allow a wide range of suspension articulation.
Besides being compact the Uni Wheel is claimed to deliver greater gear ratio reduction, which in turn improves torque. With independent control of up to four efficient electric drive motors, the Uni Wheel also allows for sophisticated torque vectoring, which enhances stability and overall driving performance, depending on the vehicle application.
The Uni Wheel optimizes battery packaging, minimizing the impact on passenger space. Traditional EVs often sacrifice passenger room due to the low placement of batteries, resulting in a raised ride height. Uni Wheel's flat-floor platform addresses this issue, enhancing passenger space, a valuable feature for PBVs seeking a low, flat-floor design.
This flexibility provided by Uni Wheel allows for the creation of new seating arrangements and designs, particularly relevant in the era of fully autonomous driving.
Also read: Review: Hyundai Ioniq 6 Max AWD - There is a price for beauty, but is it too much?
Also given its scalability, the Uni Wheel accommodates wheel sizes ranging from 4 inches to 25 inches, meaning it can be adapted for normal vehicles to mobility devices like wheelchairs, bicycles, and even delivery robots.
Hyundai Motor and Kia are actively testing and refining Uni Wheel to ensure stability, efficiency, and durability. The companies have applied for and registered eight patents related to Uni Wheel in South Korea, the United States, and Europe, emphasizing their commitment to advancing this innovative technology.