3 ms·
In-board motors, one per wheel, have all those advantages you state for wheel motors, but none of the disadvantage of excessive unsprung weight. Additionally, a
by coryrc 6y ago
In-board motors, one per wheel, have all those advantages you state for wheel motors, but none of the disadvantage of excessive unsprung weight. Additionally, a bad pothole means only replacing a cheap wheel and not an expensive motor.
Steel wheels on a 112kW car do not weigh near 43 kg. Don't fall for the empty promises.
(Random first hit: 23 lbs for a steel wheel: https://www.amazon.com/dp/B01MA3OFTN https://www.amazon.com/dp/B01MA3OFTN)
They'll never be cost-effective for freeway-capable cars. I'll make a long term bet on it with anybody.
EDIT: your linked study says you can add features to somewhat make up for the excessive unsprung weight. Sure, which is why I'm pointing out not that it can't be done, but that it costs more for the same performance and always will (at Earth gravity and freeway speeds).
- sudosysgen 6y agoSteel rims alone? No. Brakes, plus axles and various power transfer components, as well needlessly complex superfluous suspension? Yes. A very important distinction is also that the moment of inertia of a hub motor is not much bigger because the weight is concentrated in the center vs the extremities. In-board motors, one per wheel, have the issues of still needing all of the weighty unsprung mass of a car but adding additional mechanical complexity in the transfer mechanism as well as just adding mass and taking up space in general, plus needing more cooling. I am willing to bet that the braking system alone in the average car is more than 28kg. Besides, cars with hub motors that have less unsprung weight that the original car they were based one have been built, for example this one : https://web.archive.org/web/20090318173319/http://www.causecast.org/news_items/7667-michelin-unveils-active-wheel-in-affordable-electric-car https://web.archive.org/web/20090318173319/http://www.causec...