The wheels on the EV go round and round, round and round. No matter how much you rethink the wheel, they are round, but that round wheel made out of dandelions still has a lot of technology wear left in it. Continental has generated a new wheel for electric vehicles with the New Wheel Concept, which was developed to meet the specific braking requirements for EVs.
According to Continental’s press release, The wheel rim consists of an aluminum carrier star with the brake disk and the outer rim with the tire. In contrast to conventional wheel brakes, the New Wheel Concept brake actuates the aluminum disk from the inside, allowing for a particularly large disk diameter, which benefits the braking performance. EVs generate additional electricity through recuperation (braking using the electric motor), which results in extended range and the wheel brakes are used less frequently. The corrosion-free aluminum brake disk also prevents the formation of rust, which can impair the braking effect on cast-iron brake discs.
“Electromobility needs new solutions for braking technology,” said Craig Belevender, Head of Hydraulic Brake Systems for Continental in North America. “Using conventional brakes is not very effective for these vehicles. The New Wheel Concept meets all the demands that electric driving places on the brake. We used our braking know-how to develop a solution that provides a consistently reliable braking effect in the electric vehicle.”
Thanks to lightweight materials, the New Wheel Concept reduces the weight of the wheel and brake, enabling additional weight savings in EVs. Further advantages of the concept are much easier wheel and brake pad changes, as well as that the disk not being subject to wear.
The New Wheel Concept is based on a new approach towards the wheel and axle design that permits a wide brake disk friction radius since the space available in the wheel is optimally utilized. During development, the New Wheel Concept’s braking performance was initially designed for medium and compact class vehicles. In accordance with today’s requirements for this application, the brake is sturdy and fulfills all the established criteria, even though it is used much less frequently in an EV.
“In EVs, it’s crucial that the driver uses the friction brake as little as possible,” said Paul Linhoff, Head of Brake Pre-Development in the Chassis & Safety Business Unit at Continental. “During deceleration, the momentum of the vehicle is converted into electricity to increase the vehicle’s range. While the driver continues to operate the brake pedal, it doesn’t necessarily mean that the wheel brakes are actuated.”
When the driver brakes more energetically, the deceleration torque of the electric motor is no longer sufficient by itself, so the wheel brake is needed. Drivers need a reliable and consistent braking effect, which can be impaired by too much rust on the brake disk. This is due to less friction between the brake pad and the brake disk. In addition to regular braking, the automatic emergency braking function needs to fully rely on the availability of the friction brake effect.
In perfect harmony – material and design
The design of the New Wheel Concept uses the strengths of lightweight aluminum material for the brake. Thanks to the long leverage effect on the large brake disk, relatively low clamping forces are sufficient to provide a high level of braking efficiency. Since aluminum is a very good heat conductor, the heat generated in the disk during braking is quickly dissipated.
Based on initial test results, Continental assumes that the aluminum disk is not subject to wear and that abrasion only takes place on the pads. Due to an intelligent design of the Concept, replacing both the pads and wheels is very easy.
“Since the brake disk is fixed on the outside and the brake engages from the inside, the brake caliper can be designed particularly light and stiff. The force is transmitted largely symmetrically into the center of the axle, and this has a favorable effect on the noise behavior of the brake,” Linhoff said. “A side-effect that is extremely desirable in a quiet EV.”
Continental will demonstrate the New Wheel Concept during the International Motor Show, IAA in Frankfurt/Main