Behold The Hyundai Uni Wheel. Transportation May Never Be The Same

Air conditioning and touchscreens didn’t alter how cars drove but did revolutionize the driving experience.
Can we please make touchscreens for neccessary functionality illegal, like using phones while driving?
- Yeah, buttons can be found without looking.
  
  They also provide tactile feedback allowing you to be sure they have been pressed without even looking.
- THE reason i got a Mazda, after many years of Mercedes and BMW...
  
  I feel like not enough people realize how amazingly simple and tactile the rotating dial is for doing anything in a car. And especially the placement being down by your arm makes it so easy. I can feel where all those buttons are without taking my eyes off the road.
- Also make them illegal in aircraft! And spacecraft! Seriously stupid.
  
  I vote for cheap PlayStation controllers.
  
  I suppose the advantage on aircraft and spacecraft is that they consolidate functions so you don't have to have 90,000 switches in the cockpit, half of which you won't ever need.
  Anything you need to find in an emergency absolutely should be a physical switch but anything else can probably be a UI interface.
  But in the car you need to keep your eyes on the road at all times, which isn't so much of a requirement in the air.
  
  Also make them illegal in aircraft
  Salty Boeing
- So much this, it makes no sense for using a portable phone to be illegal while driving but yet my car stereo can be a full on entertainment system and require me to have zero feedback to change the channel or answer a call.
- Or at the very least, do what modern airplane cockpits do and have a trackpad/trackball on the center console.
- I'm pretty sure they are for safety critical controls, such as in an aircraft cockpit. In the automotive world, we like to keep it jazzy and smooth, like my romantic life.
  
  They aren't. Light ircraft now use touchscreens that you are supposed to use while bouncing around. They had a knob for a while but then it seemed touchscreens took over. With the knob you still had to look, it at least you didn't have to aim at a bouncing spot on the screen.

Can we have more mechanical posts like this?
- No, you need 555 posts about the shit that a billionaire said about stuff he knows nothing about
  
  And then someone saying something about Linux
  
  On Monday I'm going to tell my boss to fuck off. He isn't going to blackmail me into doing high quality work with money. Honestly, fuck off.
- Be the change you want to see!!
- A new mechanical motion is a seriously big deal and doesn't happen often.
- This requires educated users in their professions to read the news and share it to the public for free when not being paid.

There's 2 significant inaccuracies in the article and 1 large oversight in the official video.
Differentials are not one wheel drive. They can seem to drive only one wheel when spinning the wheels as one let's loose and the other stays still, but it's not driving one wheel. It's still driving both. The problem is the free wheel is spinning at twice the speed indicated on the speedometer and the other is at 0. The driveshaft puts in a certain number of turns, the wheels, together, must add up to an equal output (multiplied by the gear ratio). If the car is going straight with full traction, then they turn the same. If you floor it in snow, one is probably spinning 40% over it's share and the other 40% under. This is not unique to rwd either as fwd cars still very much have a functioning differential. To throw some numbers at it to help clarify the function, let's say the engine is asking the wheels to spin at 30rpm each in a straight line. In a left turn, the right wheel travels further and needs to spin at 35rpm while the inner spins at 25rpm. It still adds up to 60rpm, same as a straight line. Mash it in the snow and it might be 60rpm in the left and 0nin the right or 0 in the left and 60 in the left. It could be 5/55, 40/20, or any other combo as long as it totals 60.
PS: differentials are irrelevant when the wheels aren't connected to each other. Individual-motor wheels, as shown in the video, don't need a diff. The non-drive wheels in a 2-wheel drive vehicle do not have a differential on the non-drive axle.
Cv joints are not specific to fwd as nearly all modern rwd cars with independent rear suspensions have CV joints. I don't know of any trucks still using U-joints either since big trucks are solid axle. Cv joints function the same as U joints. The difference is C.V. joints output constant velocity whereas U-joints (what you'll see often under trucks on the driveshaft, two square C shaft ends with an X link between) have lopey output that gets worse with greater deflection angle. If you own a u-joint bit for your socket wrench, I invite you to play with it. Instead of a solid pinned X between the U ends, CVs have free-rolling balls that can roll inboard and outboard to maintain the link between the shaft's cup and the wheel's cone.
The article is inaccurate but the video ignores this part, so I don't fault The writer. The CV joints are said to be a poor design, yet, it ignores the part where the video reinstalls them at 4:20 and 5:10 for the front wheels. This mechanism does not allow angular deflection between the motor and hub, as it's shown, without a CV joint. Lateral displacement, yes, but not angular - as in it can't steer. This may be an overall improvement by reducing how often it needs to bend (only when steering), but it doesn't eliminate it. And even then, the rear suspension is still designed to change camber as it changes ride height. Camber is the angle of the wheel as measured top to bottom, as in what you see from looking at the wheels from the front of the car. It keeps the wheels flat on the ground as you lean the car in a corner. You may see an overloaded car's rear wheels look like /---\ as viewed from the rear or --/ when hanging free on a lift.
Look, I'm not an engineer at Hyundai (or even a competitor) but this doesn't quite pass the sniff test. Cool idea for sure, but it smells a little like marketing is clamoring for something edgy to display. Even as displayed, the motors and original reduces were already very compact and in close proximity to the wheels compared to a normal engine. The slightly reduced footprint of this uni wheel and slightly increased friction of a bunch of additional gears makes me think this is a fractional improvement in practice rather than a revolutionary improvement.
- I'd be concerned with the amount of unsprung weight this adds, too. You're basically taking the transmission and adding that mass to the hub. Seems like it would be pretty crashy on rough surfaces.
  
  I 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 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.
  
  Yep.
  Trucks used these as far back as pre-WWII. It a great solution for off road vehicles to gain clearance. At low speeds, even universal joints work fine for this setup, because the shaft rotates at 1/3 wheel speed, like a drives haft does going into a differential.
  This puts a diff at each wheel.
  Edit: These are called Portal Gears
- I noticed they conveniently didn't talk a lot about steering..
  The claim of "one wheel drive" I think is meant to highlight what happens if traction is lost. It sounds like something I have heard on 4wd off-road forums. I agree the phrase "one wheel drive" is perhaps not a great way to explain the disadvantages of differentials vs limited slip differentials vs locking differentials vs individually driven wheels.
  The idea of "one wheel drive" as I have seen it used, is that in a vehicle with one powered axle assembly (what we normally call 2wd-- either front or rear wheel drive) is that if you lose traction with either drive wheel, the vehicle no longer moves because all power is diverted to the slipping wheel.
  If you have a limited slip differential, there is a limit to how much power is diverted to the slipping wheel. With a locking differential, you only stop moving if you lose traction to both drive wheels.
  Anyway...
  The design is really interesting.
  You also bring up a good point about how camber changes with suspension position. Also the effective track width changes, such as with my 4Runner which has upper and lower control arms, a Double wishbone suspension. If the motor remains in a fixed position, the wheel will move onboard and outboard relative to the motor depending on suspension location.
  I don't quite get how these two effects are addressed with this new design. Or are the suggesting a different suspension technology that they didn't discuss?
  As for steering, I wonder if the design rotates the motor along with the wheel. In that case no CV is needed but I would guess there are some downsides to such a design.
  I agree the video seems kind of... premature. The mechanism is cool but I don't get the sense that its applications haven't exactly been nailed down yet.
  
  Individual motors on each wheel will still slip, just with half the power. So sure, it's an improvement by an unrelated mechanism, but not having the wheels connected with a limited slip means it'll still need a traction control system. And even still, the "half" power is a relative term because every car has a different output. That goes for not connecting left to right as much as it goes for front to back. So, not different than a traditional open diff or 2wd. There have been advances in brake-based traction control so they don't just cut power and apply single brakes like the 00s, they can properly modulate pressure to get equal propulsion.
  That's a good point you've mentioned as well - the wheel will change distance to the motor as it goes through it's motions. The only way to avoid that is to place the motor at the effective pivot point of the suspension which is, in a properly design suspension, inside the other wheel to mimic the level dynamics of a solid axle. That of course defeats the short halfshaft design direction. So something has to allow variation in distance. In the non-steer wheels, maybe this could be as simple as a telescoping spline drive. However, the video shows a small black joint at the same time stamps above on the rear and still has those normal-looking cv boots on the fronts.
  Or maybe they're ditching good handling and going with perfectly vertical suspension travel. Give it hard eco tires and it'll slide before the suspension shows it's flaws.
- The steering wheels' hubs rotate in two directions. The steering action rotates through a vertical axis while the typical suspension rotates in a front-to-back axis pinned approximately through the other side of the car. So unless they abandoned common suspension design to let tires lean in turns more than a reasonable amount, there needs to be an allowance for angular deflection. A pinion gear arrangement sounds like it would take up a lot of the space they're trying to save but still not solve the multi-axis problem found at all 4 wheels. I'm trying to not take their video so literally but it's not like it's a dealership rep spouting incomplete info here
  
  But you need a CV or Universal on that drive shaft to accommodate suspension travel (or steering if needed on that wheel).
  
  Unrelated comment, but holy shit I am a huge fan of the M8. So wild to see you on Lemmy, and this comment section is exactly what I'm here for.
  
  With how small the motor is you could also pivot it alongside with the wheel, after all, something pivoting with the wheel doesn't mean that it has to be unsprung.
- You are sort of correct about this, but it's irrelevant since everyone moved onto limited slips decades ago.
  As to the rest- you're wrong. Sorry.
  But the real reason this tech won't be very important is because it's a lot more complicated and expensive than a cheap ass cv joint and is minimally more efficient. I can buy both sides of my vehicle for like $80 and don't have to worry about em again for ages. I think this new hyundai stuff could be reliable, but it's going to be a lot more expensive.
  Also, they look like they'd be noisy.
  
  you're wrong. Sorry.
  No u. Bam, same level argument right there. Are you going to explain why or just throw out contrarian comments?
  Cost will not be a limiting factor. Just about every feature on a 2023 car already costs more than a 1993 car's version. Did adding a wheelspeed sensor, electronic 4-channel hydraulic brake actuator, and dedicated ecm programming cost too much to implement ABS? Did the complication of 40 sensors (100+ now) and a voodoo box of electronics cost too much to go efi instead of carbs? Did the price of disc brakes stop most cars from ditching rear drums? Did the cost of engineering and testing prevent manufacturers from implementing the following nearly-negligible aero improvements to eek out another 0.1% of fuel efficiency;
  aero strakes into mirror shells (prius, escape)
  relaminating roof spoilers into every hatchback/suv and even into every pickup bed
  Vortex generators on the top surface of tail lights (sonata, chr)
  Active grille shutters (fusion)
  Full underbody trays
  Chin spoilers (splitters) on just about every car to keep air out from underneath
  Hood beak splitters to keep grille air off the canopy (Volvo, accord)
  Short antennas/glass-embedded antennas to reduce antenna drag
  Front fender outlet vents to create laminar flow over the wheels (f150 2015+)
  No, it didn't.
  And I'd be interested to hear why you think helical-cut gears will be "noisy". I'm guessing you don't know why reverse whines in certain cars but not the forward gears
  Edit: also, seriously, go do some shopping. LSDs are on the decline. On top of never being common in the first place, manufacturers at removing to brake-based simulated LSD rather than discrete components. There are incredibly few Fwd cars that ever had LSDs and fwd obviously makes up the majority of North American sales. Even Miatas and Mustangs only get LSD with optional packages.
  
  Irrelevant since everyone moved onto limited slips decades ago.
  Lol, what?
  My RSX was made two decades ago in '03, so the newest that would be multiple decades old. It's also a Type-S, the sporty model. It's got an open diff.
  My '93 Subaru Loyale, which is 3 decades old, has two open diffs, with a locking center diff. No limited slip.
  My '04 (almost decades old) Crown Vic PI doesn't have an limited slip. It was an option on Interceptor that the city didn't opt for.
  My '07 (not decades old) Volvo XC70 has no limited slip diffs. It uses the traction control to try to imitate them, but no actual limited slip differentials.
  My partner's '07 (still not decades old) Kia Spectra5 has an open diff.
  The only car in my fleet that has a limited slip is my '02 Subaru Legacy Outback, and it was an option that the person who bought it new opted for, and it's just the rear that's limited slip, the front is still an open diff. Apparently the limited slip isn't even that good either, you can still get stuck with two wheels spinning. I haven't tested that yet, I just got the car.
  If you go out and buy most cars today they'll come with open differentials. The traction control system will likely try to compensate for this, but they do not have limited slip differentials.

Now thar Hyundai has patented it, it will never become popular enough to impact the market and be standardized in more vehicles or change anything, similar to the Wankel engine.
- similar to the Wankel engine
  Was the Wankel engine really a step forward though? I'm a gearhead who does all his own car maintenance, up to and including engine swaps in the past and retro-modding bigger turbos and aftermarket fuel injection systems into my cars (Datsuns in the latter case). That being said, I only know the very basics about rotary engines. I've always admired the Mazda RX's from afar.
  Mazda, who by no means makes a bad gasoline engine, could never get a rotary motor to last well or to have anywhere near decent fuel economy. Also, the rotary design was tried for a while in at least refrigeration compressor applications, where it blew up there a lot more than the other types of compressors as well.
  
  Yea. They have worse efficiency. To get better efficiency from them you would need to run them hotter (afaik), and if you do that they would last even shorter.
  It's great if you want a smaller but still strong engine, but it's not efficient and those seals are a big problem.
  
  The argument is, though I’m not qualified to assess it, that Wankel engines are simpler, smaller, more power dense and, if allowed time to develop, would be an improvement on the traditional ICE. It’s very difficult to assess where we would have ended up and a little by the by, given we need to move away from burning fossil fuel.
  That said, do check out LiquidPiston’s evolution of the Wankel engine. It does sort of look like they’ve solved a number of issues a traditional Wankel engine has.
- But capitalism creates innovation!!!
  
  Some people argue that intellectual property law is not free market capitalism, and is instead a regulation that benefits big business. I'm one of those people
  
  And regulations restrict both.
- "Probably failed cuz they called it the wanker engine lmao. Now set aside another few milli for the copyright lawyers"
- Indeed, nothing that is patented ever makes it to market...

Did none of you watch the video? The article is crap, but the video explains it well.
Go back and watch the video, ya old codgers!
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- I watched the video, but burying a good video under a trash article does not a good sauce make. OP should have just linked the fucking video.

One thing I took from the article is they're trying to sale the idea of having MORE space in a car due to smaller transmission system. In 1 presentation, they show the idea of putting a FUCKING DOUBLE BED IN THE CAR!
I DON'T want MORE space in the SAME sized cars.
I want the SAME space but in SMALLER sized cars.
The space we have now is FINE, and the car sizes are TOO BIG.
STOP MAKING BIGGER CARS!
- If we could get standardized and interoperable electric car parts, that'd be great.
  
  Imagine that XKCD competing standards comic here
- trying to sell* the idea
- You're complaining like this doesn't also mean the same space in smaller cars. Improvement is improvement.
- They have taken us for fools

What a badly written article, wrongly explaining both the diff and the CV joint. That's not what they do or how they work.
- Yeah, skimmed and saw one of his other articles praising the cybertruck and realized this likely wasn't a source worth absorbing.

https://youtu.be/Nd6C0y8xc20
Seems really cool. I will definitely not buy the first model vehicle to use this, though.
- Surprisingly easy to understand video for a complex concept.
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- It is made by Hyundai, I wouldn't touch anything close to cutting edge they make.
  I can already see this tech holding a yard sale on the freeway after a pothole.
  
  After owning a Hyundai I won't touch anything made by Ford or Chevy again. This car has had literally nothing wrong with it for over 70k miles. Except routine maintenance like brakes, oil changes, air filter and tires.

The explaination of how differentials work was painfully wrong. An I lost confidence in this author's ability to explain the topic.
- Ok. Care to elaborate, please?
  
  https://youtu.be/yYAw79386WI
  
  https://upload.wikimedia.org/wikipedia/commons/3/3e/Around_the_Corner_%281937%29_24fps_selection.webm
  Wiki to the rescue!
  It's a great video from 1937.
  How the automobile differential allows a vehicle to turn a corner while keeping the wheels from skidding. Reverse telecine & introduction edited out.
  And the article has info as well https://en.m.wikipedia.org/wiki/Differential_(mechanical_device)
  Modern cars have "traction control", which detects when a wheel turns more than the other wheel. If it turns too much more, it will engage a "diff lock" and lock the differential which makes each wheel turn with the same power/speed/energy as if the differential was just a solid axle.
  The long & the short of it is that a differential is only "1 wheel drive" when the differential "thinks" (it's not smart) it should put all the power into 1 wheel - which is when the cars computer locks the differential.
  
  Please forgive my laziness - https://chat.openai.com/share/45e326f5-1653-4c51-b057-b36326963559
- Came here to say this.
- It was sooooo wrong. Painful is right.

The one thing they don't really talk about is how it turns. The animations show vertical movement almost exclusively. At one point in the video there is a far shot showing a car turning and it looks like they actually swivel the entire motor to keep it perpendicular to the wheel which if true is going to pretty heavily limit it's turning angle and radius.
- The front wheels show CV-looking boots at 4:20 and 5:10. Even the rear wheels will likely need cv joints. Independent suspensions change camber with that coroner's ride height to improve traction. That's why when a car is overloaded, the wheels look like /---\ and when it's on a lift, the wheels go --/ (to varying degrees).
  
  While there is some kind of boot shown the entire selling point of this thing was that it's supposed to eliminate the need for CV joints. At that same 5:10 mark or there about you can also see the shot that appears to show the motors being pivoted to turn the wheel. I suspect these are not CV joints although they are joints most likely for camber adjustment as you point out, probably something like a universal joint.
- Not a problem in RWD applications.
  
  The whole pitch was based on replacing CV joints on front wheel drive vehicles.
  From the presentation it looks limiting and to be honest it looks a bit overly complicated and likely to have some massive early growing pains. CV joints are comparatively simple and this is supposed to be more reliable? That's not how it works.
  
  Always need a flexible joint such as CV or Universals to compensate for suspension movement. And they work in pairs, because +angular change is compensated by - angular change of opposite end of shaft.
- My guess is they will only put this on rear-wheel-drive cars. The system doesn't look like it can rotate at all on that horizontal plane and moving the entire motor (that is sticking out of the back of the wheel) is basically a non-starter.
  Edit, it may be possible to add another gear-set to enable rotation on the horizontal plane. But at that point I'm starting to wonder if the entire system is getting too complicated.
  
  Like a CV joint? They kinda made a point in how great it was to get rid of the CV joint only to need to put it back in to get steering.
- Even if it was only useful at the rear, it would allow the battery to be moved further back and produce a better weight distribution. Most cars are front-heavy.
- Ok but then torque changes when you turn the wheel. Hopefully the effects are too slight to matter

For the lazy people out there: https://www.youtube.com/watch?v=Nd6C0y8xc20
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If you're gonna go through all this trouble, why not put motors directly into the wheels? Then you can bypass the drivetrain all together and directly power the wheels.
- If you put the motor in the wheel you increase the unsuspended mass. Bad for handling and ride quality
- 4 motors is more expensive than 1 motor and a bunch of gears
  
  Do really need need 4?
  If you cant get by on 2, you might have less power, but you can get better efficiency. With better efficiency you can have a smaller battery for the same range and reduce some of your increased cost that way.
  
  And also, if one of the wheel motors breaks down will the inevitably obtuse software of the car allow me to drive on three wheels, or will it sit idle until a certified technician arrives and inputs a service code?

Not a new idea, military trucks used reduction gear drives in the wheels before WWII. Edit: Portal Gears.
One downside to doing this is adding unsprung weight, which is not a good idea.
And it will still need a CV at the wheel to accommodate suspension travel.
- You're right on unsprung weight, this is going to add quite a bit, especially if you fill the thing with oil.
  Not sure how you still need a CV though, as this performs that function. Watch the video, there's a good animation. Basically this is a reduction gear and CV joint in one unit.
  
  Camber. It allows the wheels to tilt allowing them to keep their entire tread on the ground when only one side of the vehicles suspension is compressed, like during a turn.
- Also need them to steer the car

I don't understand how they are going to keep dust and dirt out of it. The point where the drive input goes in has so much movement.
- It will have a boot or case on it and will be filled with grease. Just like a cv joint or ball joint.
  
  Then how is it an improvement?

I cannot think of a car company I'd trust less to do this than Hyundai/Kia.
- Somebody better tell them
  
  Hyundai/Kia owners have, in large numbers, told Kia Group about quality issues their cars have. Their usual response is to gaslight everyone until some government agency sues.
  
  Somebody had* better tell them

So in short, this adds suspension directly to the wheel, at the cost of higher maintenance? That's it?
- While increasing energy efficiency and available space, both of which can be used for extending EV range (by adding more batteries that deplete more slowly) - one of the biggest EV issues right now.
  Or you could just fit a mini party bus inside a hatchback, whichever you prefer.
  To your point though, one of the othe big EV issues is cost (both purchase and maintenance) - even if a large chunk of it is artificial. Wonder what the price tag and lifespan on these things will be.
  
  EV maintenance cost is quite low compared to ICE vehicles. Brakes and suspension are probably the biggest wear items, but brakes have comparatively less wear because of the regen braking.
- It's not suspension. It compacts down the differential and cv joint (linkage from the engine to the wheel).
  
  It compacts the whole drivetrain, from engine to the wheel. The space saving they were showing was mostly from the miniaturization and splitting of the motor.
- It's pretty smart. It is like a wheel-motor but without all the unsprung weight.

Article made it sound like only front wheel drive exists now and that only front wheel drive cars use CV joints lol.

Honestly I don't care at this point, I won't buy anything from Hyundai.
- I haven't been paying attention to Hyundai, what did they do?
  
  Locally (Baltimore MD), in the city at least, there's been a plague of car thefts for a while, specifically of Hyundai and Kia models. I forget the exact details, but there's a software glitch that basically makes them child's play to hotwire and roll off with.

so the pretty much only upside compared to hub motors is less weight in the wheels, and comared to conventional drivetrain layouts there's added complexity and slight extra interior space? i mean innovation is key, but i don't quite see the upsides as much as the hyundai engineers.
- I think weight in the wheels is a huge downside of hub motors though? So this kinda takes a middle ground... Unsprung weight is still increased but not nearly as much.
- Exactly.
  Has all the advantages/disadvantages of any other portal gear.
  https://wikiless.tiekoetter.com/wiki/Portal_axle
- Probably useful in other applications. A universal joint is used in so many places other than cars

This is pretty cool!
But, in the video there is a quick flash of text that went away after 1s, 120km/h max speed?
- they're probably going to improve it further

From a mechanical standpoint, the new bearing saves a nearly negligible amount of space. Splitting the motor up and moving it to the notoriously wasted wheel well space is what clears up the center of the frame. Still very cool. It's basically a single output differential, which is already quite compact. No need to split the rotation for turning since the wheels rotation will no longer be mechanically linked.
- But eliminating the long half shaft that accompanies the CV joint is what allows that space to be used.
  
  I mean you're not wrong, but without separating the single motor to one at each wheel, you'd still have to translate the power from one point to each wheel. The uni bearing doesn't provide that benefit. Separate motors DOES. And tuned and articulating short shafts are not a new thing. So even without this new bearing as long as you had separate motors for each wheel all you would have is a short CV shaft between the motor and the wheel. Hell why not save all of the space and just incorporate the motor into the hub??? Since BDC motors are more efficient when wider and smaller, it would be very easy to fit them within current day hubs.
  I mean, don't get me wrong, I honk for planetary gear designs every time. So I'm not knocking this design. It's simple, machinable, and direct. It's brilliant for what it is. It's just not the space saver that they are touting it to be. The video literally showed two seats side by side with a bed in the back. Unless kia started making a suburban, I'm just not that naive.

Anyone remember the Hyundai debacle where the transmission gears stripped mid-drive? Yeah..... I'm not trusting their gear-making ability (or lack thereof) with precision gears inside all of my wheels. Pass.
- Hyundai doesn't make gears, they buy them. Idk if they are buying them from the same distributor but I doubt it since that was a major issue.
  
  I hope not. But with their track record, I wouldn't put it past them. From my personal experience with them, I won't trust them again.

I don't get what this does or what's the benefit. There's still a cv-joint there. Otherwise the wheels can't turn
- It replaces the cv joint. Watch the video.
  
  There's the CV-joint
- It's a bit overcomplicated wheel reductor hub, used in some trucks and widespread in heavy equipement, but the input shaft can move a bit. And the artictle doesn't mention anything about oil in it or how it is sealed.
- The motor could move with the wheel, but there goes that space they saved.

I was just learning about CVJ gearing the other day and was thinking cars should use it instead of fixed gear ratios. Very cool.
- It's still a fixed ratio though?
  
  Oh I was looking at constant velocity transmissions. Similar concept to the uniwheel, as far as the gearing. As least, if I understand it correctly.

Setting aside all of the already observed questions in the comments already about mechanical viability, i.e. how this assemblage is supposed to steer. The elephant in the room is whether or not this is equivalently economical to produce compared to an axle with a CV joint in it, and/or if it will acceptably reliable for roadgoing vehicle use, what with having a shitload more moving parts in there.
The animation shows the geartrain assembly in an open faced housing, which if that's how it's ultimately designed is going to mean that there is now no way to keep the gears in a bath of oil or transmission fluid like is presently done in traditional transmissions and differentials. And yes, even in CV joints which are packed with grease inside their rubber sealing boots. I'll let you in on a big automotive industry secret: There's a reason current transmissions and other geartrain devices are kept suspended in oil all the time. A big one. One that has to do with your transmission not glowing red hot by the time you make it to your destination, or converting itself into glitter within the first mile.
Even setting aside lubrication concerns -- Maybe the thing is chock-a-block full of sealed ballraces or something, for all I know -- the big open slot they depict for the axle to move up and down in is just begging for a stone, a stick, a stray bolt, or any other show-stopping piece of debris from getting in there and causing you to have a very expensive day. Ditto with the gap around the edge of the sun gear, which is going to need a bitchin' huge mechanical seal on it at the minimum. If the solution is perhaps to put some kind of rubber boot over the opening that moves with the axle, it's going to have to be ridiculously flexible and remain so even throughout all kinds of temperatures and operating environments. Cars, you know, being devices quite infamous for being operated outdoors in the weather and all.
I mean, I can't imagine Hyundai's engineers haven't thought of this. But I wonder if this is one of those works-in-the-lab-and-test-track things, and they're expecting someone else to figure out the viability challenges.
- I guess this design would require a few seals to keep the mechanism bathed in oil and keep foreign contaminants out.
  Is there enough oil volume to keep the mechanism cool at highway speeds?
  And how do those tiny gears hold up to the loading? They seem a lot smaller than an equivalent pinion gear in a solid axle, for example And they were rather vague on their stress testing. Seemed like a bit like hand waving and "trust us bro".
- I’m in full agreement.
  Expanding on your concern about the sun gear is what dirt, brine water/winter treatment will have on the mechanism over time. The best case scenario is this becoming more inefficient over time if it gums up, the worst case is having debris act like sandpaper on the gears, ever-so-slowly weakening the teeth over time.
  Maybe they’ve thought of this but I can’t help but to think this is just trying to get a headline or two.

Another advantage of putting drivetrain components in the wheel is you can just swap them out easily rather than having to tear the engine bay apart. Really outstanding work!
- On the other hand, if you hit a pothole is it gonna completely fuck up your engine? I know they mentioned stress tests, but that would worry me.
  
  Yeah, I think they can solve those problems but I don’t want the first or second generation
  
  That was my thought as well. The pinion gear linkage looks comparatively fragile with its smaller gears and levers. Smacking a deep pothole at speed would likely cause the pinion gear to smack against the wheel, which wouldn't be good.

I know Hyundai is Korean and all, but this presentation style where the host pretends to be demonstrating a product "uh, wait a second . . . what if we" and is speaking almost like it's a personal conversation between the two of you is giving me huge Nintendo Direct vibes when they demonstrate unreleased games and play them for you.
Is this a common sort of business/sales presentation method in SEA?

There needs to be more music in the background, and the narrator needs to speak with more enthusiasm about more needless details of how smaller makes it possible to use the space for something else. /s
The concept is cool though.

So how does it handle potholes?
- you didn't watch the whole video huh?
  
  Video is like the worst possible way to demonstrate something.
  I can't watch a video at the moment as I'm busy not working. I need quiet text thanks.
  
  For some reason video wouldn't play on mobile for me, if anyone had a similar issue here's the link: https://youtu.be/Nd6C0y8xc20

BEHOLD
- Corn?

Seems like this adds more than a bit to the unsprung weight of the wheel.

This is cool, but wouldn’t it make any tire issue an engine issue and this way more expensive and difficult to deal with?

Fascinating, but in the video they very quickly swipe off-screen that the top speed their new system was able to achieve was 120 kph / ~75 mph.
I imagine something like this would have to be limited to vehicles that never need to approach speeds above that on a highway, so maybe busses or indoor shipping & receiving vehicles.

Neat!

That's neat, I'm looking forward to electric vehicles with the sort of modularity and space they are envisioning due to the extra space.

EV already have much smaller gearboxes, because they don't need to shift.
Now they need 4 of them, not just 1.
Such a gain in weight :-)
- This isn’t a gearbox. It’s a means of transferring power to the wheel, while having the electric engine sitting right next to the wheel.
  
  This isn’t a gearbox.
  Then it's the replacement for one.

I don't need video(s) to understand the subject here : I just use an image search :
https://duckduckgo.com/?q=%2B%22Hyundai+Uni+Wheel%22&t=ofa&iar=images&iax=images&ia=images
This is a mechanical device that allows coupling of any wheels of any vehicles to any electric motor.
it is designed in such a way to permit vertical movement of the wheel without the need of such movement of the motor. So basically it is a new type of suspension.
Since it needs many gears in a row for the transit of mechanical energy it will incure an inefficiency factor.

Expected a monowheel got something about cars. Blegh.
- Cars are never going away entirely, and no one wants them to.
  If we can make them better.. then that's great
  
  no one wants them to
  Well, some people do... but those people are out of touch with reality.
- I think it's actually pretty cool. Takes the sprung weight of an electric motor and reduces it's footprint significantly allowing for more range in electric vehicles because now that footprint can be used for batteries. And it doesn't sacrifice driveability or comfort? Kind of revolutionary. If it allows for streamlining of manufacturing it could help bring down the cost of electric vehicles which would make them more palatable for people who don't live in the most ideal place for an electric vehicle. Especially with increased range. It would also allow for hopefully less moving parts that fail and need to be replaced.
  
  Almost no vehicles have unsprung motors anyway.
- What makes you think a monowheel could be remotely preferable to cars in any possible way, whether from an individual or societal perspective?