Comment on Behold The Hyundai Uni Wheel. Transportation May Never Be The Same
XeroxCool@lemmy.world 11 months agoI considered that but couldn’t make any conclusions. The driveshaft and sun gear are not added to the unsprung. I’d guess only half the weight of planets and carriers is added. It definitely adds the weight of the ring gear to both the unsprung mass.
I’m also curious how this affects rotational mass. So while every component spinning with the wheel from tire to motor shaft has rotational inertia, small-diameter components such as drive shafts have relatively little rotational inertia. Wheels and even brake discs have a lot more. I don’t have numbers obviously but I’m curious if the rotational mass of the ring gear ends up being detrimental compared to a heavier-weight lower-inertia cv setup.
barsoap@lemm.ee 11 months ago
Isn’t the ring gear the wheel body (or whatever it’s called), that is, even a fixed axle would have weight there, the gearteeth even provide stiffness. CV joints also contain unsprung mass, I’d say there might be a bit of a difference but nothing drastic. With modern fancy biomimetic wheel body geometries and everything you’ll probably definitely be lighter than 80s steel rims. What happened to spoked wheels, anyway.
BearOfaTime@lemm.ee 11 months ago
The CV only contributes half it’s mass to unsprung weight, and this system still requires a drive shaft and either a CV or u-joint. But with more mass at the hub.
Typical hubs are still lighter than this, because this setup still requires the hub structure, it’s just adding gearing out there.
barsoap@lemm.ee 11 months ago
Half of the hub is unsprung, the transition between sprung and unsprung is at those fancy articulating planetary gears. The drive shaft is definitely sprung, it and the motor is completely static relative to the battery and everything.