141–150 of 192 posts
Excellent for sales/mechanic! Now wheel will cost more than chasis $)
And gears close to wheel used in off-road vehicles looong time, to create more clearance but they was headache, because need much additional mechanic time, and there was huge losses.
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You could probably get away with changing the tires, rather than replacing the entire wheel. The more interesting question to me is what happens if you get a flat tire? Does everyone need to carry a spare uniwheel, or wait to get towed?
Most people wait to get towed these days on those rare occasions that they get a flat tyre. In over forty years of driving I've only had three flats. One I changed the wheel, the second I just drove slowly for twenty miles because the tyre was at the end of its useful life anyway, the third was on a narrow rural road on a slope so in the winter in the dark so I just waited for the car to be taken away on the back of…
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Unsprung mass sucks. You don’t notice on smooth surfaces, but if you are cornering on a rough surface the wheel ends up losing contact with the ground after each bump. It’s extra-dangerous when its the rear wheels because the car can spin out.
It's not unsprung. The wheel and gear bit are the only unsprung parts; think of it like the motor attaching directly to the wheel bearing, and the wheel is able to move vertically on the bearing. I think this only works with RWD, because the turning wheels can't be sprung without also having to rotate the springs. It would be a better suspension (closer to racing suspensions) than standard, because wheels wouldnt toe…
"This does raise the question of why not just attach the motor straight to the wheel. The standard response is ...unsprung mass"
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The wheel can move up and down relative to the motor, so you can still attach a shock absorber to the wheel, without the motor being involved. The video shows this at 2:36.
Yes my point is, why have the complication of this set up at all.
Benefits according to the article: "reduced packaging size, improved ride quality, greater durability and, importantly, increased efficiency."
This wouldn't have worked for ICE cars, because in order to have a reasonable range of up-and-down movement the gear ratio needs to be quite high (ie, the pinion gear has to be much smaller than the ring gear). It's 6.2:1 in the article, about 2x what's appropriate for the top gear on an ICE car.
I think this could have worked with an ICE, but there is no real point: the CV joint is simple and the advantages to this don't apply when you have a single large power source.
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Looks like they already abandoned that idea: https://mwmotors.cz/luka-ev-traditional/
Interesting, I wonder what the technical reasons were for the change. It has gone this way with pretty much every hub motor concept that I've seen so far, either they don't make it of the drawing board, or they end up abandoned at the prototyping stage. The GP had me wondering if someone had actually managed to conquer it but alas that doesn't seem to be the case. It's a neat little car though, reminds of the Daihats…
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I thought the same thing and was disappointed to see a planetary gear setup to turn an outer ring gear. Shame, we have come so far in EV motor design and yet Hyundai seems stuck on drivetrain power design.
My experience with a planetary gear in a bicycle is that it produces additional noise. I wonder if this would be noticeable for an automobile.
Maybe I can't tell from the video, or maybe they're not working on this yet... But what about the steering wheels? Surely the driveshaft will have to have a joint on it on the front wheels in order for the front wheels to turn? Also this doesn't look like it would deal with camber changes which are needed to keep your tires flat on the road when cornering...
I also notice that unsprung weight was not mentioned. The "Uniwheel" clearly has advantages over CV joints, but it also looks like a significant increase in unsprung weight. They also gloss over "splitting the motor". It looks like 4 individual wheel motors, which would indeed be optimal for the torque vectoring that they mention. Still, looks like a very cool development. I hope it works out to be a real advance
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Most people wait to get towed these days on those rare occasions that they get a flat tyre. In over forty years of driving I've only had three flats. One I changed the wheel, the second I just drove slowly for twenty miles because the tyre was at the end of its useful life anyway, the third was on a narrow rural road on a slope so in the winter in the dark so I just waited for the car to be taken away on the back of…
I have yet to buy a car without one, but I suppose that'll be changing soon enough.
I guess they will still need a cv joint, just because wheels get out of alignment all the time. That aside, it would interesting if someone made a 3d model one could print to try this out at home for small robots.
Looking at the video on their website it seems the EV motors are supposed to be mounted directly into each wheel, then you only need to account for oscillations on the X and Y axis.