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.
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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
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?
We both know the answer to that question. And boy howdy am I stoked for cars to get fully enshittified where you have to have a yearly subscription for the software that allows your tires to move, otherwise you functionally just bought a 45,000 dollar paperweight.
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.
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.
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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.
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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.
It directly replaces the CV, so it’s the thing saving the space. Sure, if there was still only one motor, and a shaft connecting the two sides, less room would be available. But the space saving, and the reason why splitting the motor in two makes sense in the first place, is the uni wheel.
Also, yes, there are shorter CV joints, but they lose efficiency the shorter they are, because they need to translate through larger angles.
As to why putting the entire motor into the wheel isn’t a great idea for cars is because you want to keep as much weight of the vehicle on top of the suspension. If the motor is in the wheel, ride quality will suffer due to the increase of unsprung weight.
Ah, really good points. Thanks for the perspective. My expertise (if I may so generously call it that) ends at the manufacture and assembly processes. Thanks for the perspective.
Honestly, I get most of my knowledge from watching a bunch of youtube videos, so it’s not like you’re talking to an engineer or anything haha
But I do usually like to pick out the more technical videos, explaining the theory behind all this, so I guess I picked up on some things ^^
Having these gears in the hub instead of a motor would decrease unsprung weight.
The gears are necessary to allow the wheel to move without having to move the input shaft.Edit: sorry, I misunderstood your comment. I agree.
Somehow I thought you’re saying the gears should be attached to the motor.
I didn’t think about that. Thanks for pointing it out.
Can we have more mechanical posts like this?
This requires educated users in their professions to read the news and share it to the public for free when not being paid.
Be the change you want to see!!
A new mechanical motion is a seriously big deal and doesn’t happen often.
No, you need 555 posts about the shit that a billionaire said about stuff he knows nothing about
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.
And then someone saying something about Linux
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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.
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.
There’s still CV-joints there in the video despite the uniwheel. You can’t turn the wheels without one. I’m probably just not understanding this but seems like instead of making the drivetrain more simple this just adds more moving parts that’s going to need oil changes and replacing.
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.
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Ok but then torque changes when you turn the wheel. Hopefully the effects are too slight to matter
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I think they’re getting at the fact this design would generate massive amounts of torque steer. With the motor input vertical, any rotation will also try and change your steering direction.
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.
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.
A U-joint has worse modulation between input and output than a CV joint. However, I did look again at the video as big as I could and you are right, the motors are pivoting. It seems to only pivot a partial amount and still at an angle to the wheel. Something is still being glossed over.
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.
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’m glad you said it this time. My fingers are starting to get tired from harping on them all the time.
And I will fight you before you confiscate my last motorcycle.
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My completely unfounded hypothesis is that a lot of these guys are just all sour grapes because they are in a position wherein they can’t afford a car (or a motorcycle, or whatever). So they think everyone else should be miserable like them, too.
The environmental aspects I get, but I also get the feeling that’s actually just a post-hoc rationalization to the whole no-personal-transportation sect.
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I had three cars and a motorcycle at one point, though now I’m down to one car and a bicycle. But whatever makes you feel superior, I guess. Fuck the people with legitimate ideas to improve life and the environment.
I have one word for those people:
Ambulance.
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I don’t want to get rid of cars as a technology, just privately owned passenger cars.
Certainly with the reality of suburban life in the US.
Reality is what we make it. Fuck cars
Nah they’re great. And they’re not going away, thankfully.
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.
My 50cc scooter does! And I guess technically my electric bicycle does too, because it’s got a rear wheel hub motor and the wheel is on its own suspension independent of the frame.
…That’s about all I can think of off the top of my head, actually.
Because it throws things out of balance a lot of the time and causes damage to the components.
What makes you think a monowheel could be remotely preferable to cars in any possible way, whether from an individual or societal perspective?
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.
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.
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.
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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.
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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.
- 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.
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.
Yea, companies love to tout their “electronic differential” that’s nothing more than an open diff and traction control via the brakes (Toyota Tundra comes to mind, as recent as 2017).
Yeah. I guess the person I replied to fell for their marketing? However, even traction control wasn’t terribly common 20 years ago. I’m not sure what they’re on about.
It surprises the hell out of me that ABS wasn’t even mandatory in the US until 2008 I think. Retro mustangs were available without it. I think we got mandatory tire pressure monitoring around the same time, actually, although it was done by comparing wheel speeds over time. So yeah, traction control wasn’t all that common indeed. I think GM was still running 3-channel ABS on their trucks then too
Me too, it was super late. However, holy crap it’s different in quality between manufacturers.
My RSX has great ABS, even on gravel or in the snow. It does way better than I could in most situations. Coming from my '98 corolla (without ABS) to the RSX was a massive improvement in braking.
The ABS on my Crown Vic, which is one year newer than my RSX, just doesn’t work. You don’t lock up the wheels, so I guess by the definition of ABS, it works. However, the ABS also increases your stopping distance by a lot. I need to figure out the best way to disable it. Pulling a fuse doesn’t work, as that’s also the fuse for the dash instruments. When I do it I’ll do a test to make sure that the stopping distance is improved by as much as I think it will be.
That’s interesting, so it is pulsing under heavy braking? Is that a common problem? I wonder if either unplugging all the sensors or maybe the module itself would disable it. Just the sensors might freak it out and cause constant abs actuation each startup until it confirms the fault.
Just how many cars do you have, exactly??
- It’s a hobby. I justify it because they’re worth under 15k combined. Many folk have two cars worth double of all 6 of mine combined (licensing/insurance included)
The RSX is on the chopping block. I want to get a more dedicated sports car, since I’m privelaged enough to own multiple vehicles.
The Outback and Volvo are wrecked title purchases from copart that I’ll get salvage titles for, then enjoy for a bit before selling to break even, or even for a possible profit.
The crown vic is my beater. I drift it. I take it on logging roads. I take it on the Gambler 500. It’s fucking awesome. I’ll always have one, probably.
The Loyale is something I’ve wanted since highschool. I love the push button 4WD. I love how comically slow it is. I love the interior. I get quite a few compliments on it. It needs some work, but that’s part of the fun. I dunno if I’ll own it forever, but I really like the thing.
I, as of recently, own my grandpa’s 1984 Oldsmobile Delta 88 Royale. I’ve gotten similar compliments to the Loyale on it. My grandpa is about two weeks away from dying of cancer. I’ll own that car forever.
My partner owned a Spectra5 when I met her. It’s our economy car, which every household needs. I’d like to upgrade it to a Volt at some point.
I definitely own too many vehicles, but I love the variety and unique characteristics of each of them.
Sort of related, but I’m not one of those dickish gearheads, I use and support public transport, and think that the world as a whole would be better off with fewer cars. If one doesn’t want to drive, then they shouldn’t fucking have to.
Hey don’t let me take your fun away from you. I just think it’s an unusual amount of cars, but if you enjoy it then that’s great! Sounds pretty cool tbh
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;
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aero strakes into mirror shells (prius, escape)
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relaminating roof spoilers into every hatchback/suv and even into every pickup bed
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Vortex generators on the top surface of tail lights (sonata, chr)
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Active grille shutters (fusion)
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Full underbody trays
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Chin spoilers (splitters) on just about every car to keep air out from underneath
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Hood beak splitters to keep grille air off the canopy (Volvo, accord)
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Short antennas/glass-embedded antennas to reduce antenna drag
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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.
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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.
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.
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
Not quite portal gears, that has the input shaft fixed at the top. This is like an adjustable portal gear.
Meh, it’s still a portal hub, where you put the input shaft is a minor difference. It’s still putting the gearset in the hub, increasing the total weight of the vehicle, and increasing unsprung weight.
Calling it a new thing is a lie. All they’ve done is switch it to planetary gears. I’d bet lots of money this was tried a long time ago, and was shelved in favor of an offset input shaft.
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.
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.
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.
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.
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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
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.
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But you need a CV or Universal on that drive shaft to accommodate suspension travel (or steering if needed on that wheel).
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Now imagine there is a handle sticking out of the crankshaft that needs to rotate around the shaft with the hand crank as it gets turned. That is the motor.
The video never showed the motor moving along with wheels turning, only the up and down part. In fact, when they showed space savings they showed the motors as stationary with no clear way to turn.
Suspension movement still requires flex in the shaft. There’s no way around it unless the engine moves with the suspension
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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.
The explaination of how differentials work was painfully wrong. An I lost confidence in this author’s ability to explain the topic.
It was sooooo wrong. Painful is right.
Came here to say this.
Ok. Care to elaborate, please?
Please forgive my laziness - https://chat.openai.com/share/45e326f5-1653-4c51-b057-b36326963559
https://upload.wikimedia.org/wikipedia/commons/3/3e/Around_the_Corner_(1937)_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.
That’s only some cars.
Many today still use open diffs. Some use open diffs and braking to produce a result that looks like traction control or a torque biasing diff.
Some cars use electronically-controlled diffs that can vary pressure on clutches using simple electric servos to bias torque - Bendix is a big supplier of such things to companies like Honda.
Others use hydraulics, similar to torque converters, to bias torque (e.g. Audi’s original Quattro system).
And others use gearing to bias torque, such as Quaife differentials.
Factory systems (with rare exceptions) don’t use locking diffs (GM has one as an option, others may).
Here is an alternative Piped link(s):
https://piped.video/yYAw79386WI
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I’m open-source; check me out at GitHub.
Perfecter
That was awesome and perfectly explanatory. I learned something new today
There are a lot of these from back in the couple of decades after WWII when society actually cared about science and knowledge and companies used the spreading of knowledge as a selling point.
There’s a bunch of old training vids like that on YouTube. Lots of people could learn how to present from them - they’re so much better than most stuff on YouTube.
Perfect
Apparently I can watch that video every couple months and still be equally amazed by it.
Please remind me to watch this again in a few months, it’s super cool.Right?
I’m continually blown away at what 19th-century engineers understood and could do.
I knew exactly which video that would be. Such a perfectly clear explanation.
This is cool, but wouldn’t it make any tire issue an engine issue and this way more expensive and difficult to deal with?
Seems like this adds more than a bit to the unsprung weight of the wheel.
