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.
Ok. Care to elaborate, please?
Please forgive my laziness - https://chat.openai.com/share/45e326f5-1653-4c51-b057-b36326963559
Perfect
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.
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Perfecter
I knew exactly which video that would be. Such a perfectly clear explanation.
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.
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).
Came here to say this.
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.
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 don’t need video(s) to understand the subject here : I just use an image search :
https://duckduckgo.com/?q=%2B"Hyundai+Uni+Wheel"&t=ofa&iar=images&iax=images&ia=imagesThis 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.
What makes you think a monowheel could be remotely preferable to cars in any possible way, whether from an individual or societal perspective?
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.
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.
Reality is what we make it. Fuck cars
Nah they’re great. And they’re not going away, thankfully.
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.
Certainly with the reality of suburban life in the US.
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.
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.
The axis of the motor doesn’t need to be parallel to the axis of the wheel.
If the axis of the motor is vertical, you could use a ring and pinion gear to transfer the torque to the driveshaft running out to the wheel, and have the steering wheels pivot around the axis of the motor.
Ok but then torque changes when you turn the wheel. Hopefully the effects are too slight to matter
Please elaborate.
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.
Driving the streering wheels exerts a force on the driving surface. That causes the steering wheels to have a tendency to toe in.
Looking from the top, you could run the motor clockwise on the right side and anti-clockwise on the left to cancel some of that, but the motor has very little leverage compared to the wheels.
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.
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.
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Can we have more mechanical posts like this?
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.
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
deleted by creator
For the lazy people out there: https://www.youtube.com/watch?v=Nd6C0y8xc20
Here is an alternative Piped link(s):
https://www.piped.video/watch?v=Nd6C0y8xc20
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I’m open-source; check me out at GitHub.
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.
This is cool, but wouldn’t it make any tire issue an engine issue and this way more expensive and difficult to deal with?
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”.
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Article made it sound like only front wheel drive exists now and that only front wheel drive cars use CV joints lol.
Seems like this adds more than a bit to the unsprung weight of the wheel.
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?
