Imagine this: Your electric vehicle doesn't just accelerate like a rocket; its rear wheels become the brakes! British firm YASA is making this a reality, and it could revolutionize EV design.
Their secret? Axial flux motors, which are not only incredibly powerful but also potentially eliminate the need for large rear brakes.
Here's the deal: EVs already rely heavily on regenerative braking, which uses the motor to slow the car and recapture energy. This means traditional mechanical brakes are used less. Since most braking power is concentrated at the front, rear brakes can be downsized. Volkswagen's ID.4, for instance, uses rear drum brakes. But YASA is taking this concept to a whole new level.
In a recent announcement, YASA unveiled a prototype in-wheel motor. This innovative design combines their axial flux motor with a compact inverter. The result? A staggering 750 kilowatts (986 horsepower) per wheel! According to YASA, this could lead to dramatically smaller rear brakes.
Tim Woolmer, YASA's Chief Technical Officer, explained that the motor is designed to handle all the thermal demands of braking. Safety backups would include a small emergency brake or even the motor itself acting as a brake, even if electronics fail.
The benefits are compelling: lower weight and a more compact design. The motor itself, without the inverter, weighs a mere 27.9 pounds and boasts incredible power density. In a dyno test, it generated 26.7 kW per pound – a potential world record! Factoring in the reduced weight from smaller brakes and other components, YASA estimates a total weight saving of around 440 pounds.
But here's where it gets interesting: Several companies have tried to bring in-wheel motors to market, but YASA's technology seems particularly well-suited. Axial flux motors are thinner than conventional radial flux motors because the magnetic force travels parallel to the axis of rotation. This allows for a more compact form factor, perfect for fitting inside wheel hubs.
Weight reduction is crucial for in-wheel motors, as unsprung mass is a major hurdle. While YASA's design is still in the prototype phase, the potential is undeniable. Mercedes-Benz, YASA's parent company, has already showcased these motors in concept cars like the Vision One-Eleven and AMG GT XX.
What do you think? Could this be the future of EV braking? Do you see any potential drawbacks or challenges? Share your thoughts in the comments below!
