The electric vehicle (EV) revolution is rapidly reshaping the landscape of personal transportation. As battery ranges improve and charging infrastructure expands, EVs are transitioning from novelty to norm. At the epicenter of this transformation lies the very heart of the vehicle – the drivetrain. This critical system, responsible for transferring power from the motor to the wheels, is undergoing a radical reimagining to unlock the full potential of electric mobility.
Leading this revolution is Hyundai Motor Group and its trailblazing Uni Wheel concept – an ingenious drivetrain design that embeds the entire propulsion system within the wheel itself. This disruptive approach promises enhanced efficiency, dynamics, and versatility compared to traditional EV layouts.
The Rise of the E-Axle
The bulk of modern EVs utilize compact, modular e-Axle units to power their wheels. Integrating the electric motor, gearbox, and differential into a single self-contained unit, e-Axles offer substantial space savings compared to bulky combustion engines and complex transmissions.
Typical e-Axle positioning in modern EVs mirrors their internal combustion predecessors, with prime real estate beneath the cabin occupied by a large centralized motor powering either the front or rear wheels. Some performance models utilize a dual layout with an e-Axle at both axles.
While the e-Axle minimizes the intrusion of oily machinery into the cabin, its concentrated mass still consumes valuable space that could enable more capacious and flexible interior designs. This antiquated convention of a centralized power unit is precisely what Hyundai seeks to challenge with its radical new drivetrain concept.
The Wheel Reimagined with Uni Wheel
Hyundai’s ingenious Uni Wheel rewrites the rulebook on EV drivetrain conventions, essentially miniaturizing the entire e-Axle down to the scale of a pizza and embedding it directly within each wheel.
This revolutionary integrated hub motor eschews traditional half-shafts, differentials, and gearboxes in favor of a compact planetary gear system encased within the wheel. Power from the battery feeds compact permanent magnet synchronous motors within each Uni Wheel, which then transfer torque to the road via this intricate gearing.
The layout bears an uncanny resemblance to our solar system – with the motor assuming the role of the Sun at its heart and an outer ring gear orbiting the rim like Saturn. Sandwiched between lies a quartet of pinion gears that bridge the gap between sun and ring, ensuring smooth power transmission even as the complex suspension articulates.
This ingenious arrangement allows each self-contained wheel system to receive and modulate power individually – granting unprecedented granular control while eliminating energy losses in traditional driveline components. Let’s delve deeper into the anatomy and functionality of Hyundai’s avant-garde drivetrain concept.
Anatomy of the Uni Wheel
Hyundai filed extensive patents unveiling the intricacies behind its futuristic Uni Wheel module, which integrates the following components into a single, compact unit:
- Permanent magnet synchronous motor
- Planetary gear reduction system
- Electronic parking brake
- Control module with integrated inverter
Permanent Magnet Synchronous Motor The compact yet powerful permanent magnet synchronous motor forms the beating heart of the module. Positioned at the center of the hub, it receives electricity from the battery to generate torque instantly on demand. The pint-sized electric motor provides a higher power density compared to asynchronous induction motors common in EVs today.
Planetary Gear Reduction
This critical component utilizes the internal gear train to reduce the high rotational speed of the electric motor to slower wheel speeds while multiplying torque for strong acceleration. The elaborate four-pinion layout keeps all components engaged regardless of wheel articulation, ensuring constant power transmission.
Integrated Brake and Control Module Hyundai houses the parking brake actuator and control module with the integrated inverter neatly within the Uni Wheel. This minimizes external components while granting each wheel smart autonomous control via the small onboard computer.
Benefits of Hyundai’s Revolutionary Drivetrain
By effectively embedding the heart of the powertrain within each wheel rather than beneath the chassis, Hyundai’s Uni Wheel concept unlocks profound benefits unmatched by traditional EV layouts. Let’s examine some of the key advantages conferred by this trailblazing new architecture:
- Enhanced Interior Space
Removing bulky components from beneath the cabin creates opportunities for more spacious and flexible interior configurations. The expanded footwell and flatten floor enabled by the in-wheel motors allows for greater entry and exit ease while providing intelligent storage solutions.
- Lower Center of Gravity
With heavy motors located at each wheel rather than centralized mass hanging below the cabin, vehicles equipped with the Uni Wheel system enjoy a lower center of gravity. This enhances high-speed stability and handling for a more planted ride.
- Precise Torque Vectoring
Independent power at each wheel provides unprecedented traction control authority not possible in conventional EVs. This enables sharp turns facilitated by counter-rotation torque vectoring, using opposite lock at the inner and outer wheels. Similarly, calibrated application of power side-to-side can enhance high speed stability.
- Improved Off-Road Capability
The ability to accurately meter torque to individual wheels is a boon for traversing low traction surfaces. Carefully balancing the torque load prevents wheel slippage, enabling remarkable traction even on slippery terrain. This helps URW-equipped EVs retain mobility no matter the road conditions.
- Dynamic Performance Tuning
With direct wheel hub access, the compact yet powerful motors of the Uni Wheel system lend themselves to easy performance upgrades, allowing aftermarket specialists to extract even greater power. The modular layout also streamlines production of specialized performance variants from the factory.
- Modular Scalability
The self-contained Uni Wheel modules offer versatile applicability across vehicle segments, from compact city runabouts to heavy-duty trucks. Their compact nature facilitates flexible packaging, with the number of driven wheels customizable to application. Costs are contained via mass production of a single module scaled across models.
Smoothing Out Roadblocks to Reality
While Hyundai’s Universe Wheel drivetrain ushers an exciting new chapter for electric mobility, a few hurdles stand between its radical conceptual roots and widespread commercial adoption.
- Acoustic Refinement
The location of mechanical components within the wheel brings potential for new noise pathways into the cabin. Meticulous acoustic engineering is vital to attenuating gear whine from the transmission and electric motor hum for a pleasantly quiet cabin. Specialized dynamic dampers and sound insulation solutions will be critical.
- Reliability Testing
The intricacy of the planetary gear system and susceptibility to debris ingression pose concerns regarding reliability and durability. Extensive testing over millions of articulation cycles will help validate longevity claims and build confidence for real-world deployment.
- Steering Integration
Early prototypes of the URW lacked a steering solution, using Simple pivot turns by varying wheel speeds. For practical applications, a compact steering knuckle integrating tie rods for full dynamic steering control is essential. This demands careful packaging within the space-constrained wheel.
- Serviceability
While self-contained, integrated wheel systems simplify manufacturing, they risk higher repair costs if issues arise. Smart prognostics to catch problems early and quick-swap modular designs will be pivotal to avoiding extended downtime for owners.
Pioneering New Possibilities
Hyundai’s revolutionary Uni Wheel drivetrain concept emphatically proves that thinking outside the box can deliver profound advancements where convention falls short. By literally reinventing the wheel, Hyundai has taken an audacious step towards unlocking a new era of boundless possibility for electric mobility.
While skeptics will rightly question its feasibility in the near term, visionary concepts like this help jolt the industry out of stagnant patterns into uncharted territory ripe for innovation. Just as gas tanks migrated inboard over a century ago, perhaps the next 100 years will witness the mechanicals once again returning inside the wheels – where it all began over a 1000 years ago.
Hyundai Hints at Steer-By-Wire Integration for More Extreme Mobility
Emboldened by the radical drivetrain innovation of its Uni Wheel technology, Hyundai Motor Group is doubling down on next-generation mobility solutions with its unique take on steering systems in electric vehicles.
The recent unveiling of Hyundai’s MOBION concept electric vehicle, created by subsidiary Hyundai Mobis, gave the public its first taste of the futuristic “e-Corner System. This proprietary package aims far beyond enhancing drivetrains, promising to fundamentally redefine chassis mobility.
At its foundation lies fully decoupled, individually controlled wheels akin to the Uni Wheel detailed earlier. However, while the Uni Wheel redesigned the transmission of power to the tires, MOBION’s e-Corner system takes things further by integrating critical chassis functions like steering, braking, and suspension duties directly into each wheel system.
This effectively creates four independent robotic wheels, granting the vehicle complete omnidirectional movement including crab-walking diagonally and even rotating in place. Such remarkable maneuverability could enhance safety in urban areas, tight parking garages, and off-road trails. But just how does Hyundai steer its ambitious steering solution towards reality?
Steer-by-Wire Hints
A key enabler for MOBION’s advanced omnidirectional capabilities is full steer-by-wire integration. This allows the vehicle dynamic control module to articulate wheels without the constraints of traditional mechanical linkage.
By ditching cumbersome steering columns and racks, the compact packaging of the e-Corner Module creates space for components like airbags within the cabin. This minimizes injury risks while granting designers immense freedom sans bulky equipment intrusions under the dash.
MOBION’s steer-by-wire system utilizes sensor data regarding vehicle parameters like speed, wheel orientation, and steering angle to enable tailored assistance optimized for every maneuver. For example, low speed turns can remain easy while stability increases proportionally during highway cruising.
Built-in safety mechanisms integrate redundancy through twin communication channels and backup mechanical links between the wheels that re-engage during failures. Autonomous emergency features bring the vehicle to controlled stops if systems are unresponsive.
Logistics solutions company Hyundai Glovis recently acquired a majority stake in Ohira Corporation, a Japanese startup pioneering compact steer-by-wire systems. Their technology dubbed “True Steer” is being closely integrated into Hyundai’s new concept vehicle developments like MOBION.
True Steer essentially eliminates traditional front wheels, replacing them with compact single-wheel modules each housing their own motor, brakes, suspension, and steer-by-wire articulation mechanics. This wheel-as-a-vehicle approach further shrinks the e-Corner module while enhancing safety via built-in redundancy.
Paving a Roadmap for Mass Adoption
MOBION’s radical maneuverabilityhints at a tantalizing mobility future unfettered by vehicular conventions from the internal combustion era. However, several key challenges still stand in the path to mass production.
Hardware costs may remain prohibitively high for mainstream vehicle segments for years barring breakthroughs in economy of scale. Extensive testing and validation are also needed to comply with safety regulations across global markets.
Gradual deployment in commercial mobility fleets allows accelerated cost reduction before transitioning key technologies into production passenger vehicles. For example, Hyundai’s IONIQ5 already incorporates elements of the e-Corner system in its optional four-wheel steering variant that sharpens agility.
As solutions emerge to tame costs while advancing safety, expect steer-by-wire enabled omnidirectional mobility to inch closer towards becoming an extraordinary yet everyday reality. Hyundai‘s showcar concepts provide an electrifying glimpse into the autonomous ecosystems of tomorrow, where vehicles dance eloquently around us in perfect synchronicity.
