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Hyundai Uni Wheel electric drive system could revolutionize EV design

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Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#61

Post by robocat »

seltzered_ wrote: post #18

FWIW, there was recently a now-defunct car company (Lordstown motors) that utilized an in-wheel motor from the company Elaphe ( https://in-wheel.com/en/technology/#in-wheel-motor-technolog... ) I think the tradeoff is between more flexibility & fewer parts (no cv joints) but possibly more rolling resistance. But watch the video, this uni-wheel thing is different. It isnt an in-wheel motor, more of a cv-joint alternat…

I'll be interested to see if the Elaphe in-wheel motors are designed into a high ground clearance 4WD. The site says added weight 25-65kg but maybe that is two motors for 2WD? A grunty 4WD tyre like a 33 inch (33/12.50R20) might weigh 33kg per tyre (not sure if rim weight), so the additional unsprung weight for the motor is comparatively reasonable per wheel? In-wheel would allow the suspension to be designed for much better clearance (since no shafts). Tyre might have a speed rating of Q (99mph).

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#62

Post by modeless »

chris_va wrote: post #34

Seems like it's only in-plane motion, so the wheel can't tilt/turn? I assume that means they still need a CV joint for the front wheels regardless, and that it gains no camber when cornering.

One of their animations indeed showed a CV joint in between the motor and the device. But you only need one and it can be absolutely straight when the car is not turning so the efficiency should be good.

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#63

Post by justinclift »

husam212 wrote: post #56
hooby wrote: post #47

The thing I see not mentioned in the article/video, is how the wheels can tilt/turn/angle - without needing a CV joint again. The designs seems to cover all the motion of the wheel in the suspension - but I don't see how this could accommodate steering. Is this for back wheel drive only? Curiously the animations shown in the video, show the uni wheel used in the front of a front wheel drive car - but without ever sho…

Maybe the motor is supposed to turn with the wheel, that doesn't sound like a good idea.

That'd make the motor the pivot point. No idea if that's good or bad though. :)

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#64

Post by throwaw33333434 »

jacquesm wrote: post #38
grogenaut wrote: post #26

Earlier quoted context omitted.

unsprung weight I believe is also a big issue with hub motors esp as you get up to car size at speed

It is the issue for in-hub motors. Solve that one and the world will beat a path to your door and shower you with money.

The other issue is that potholes my get quite expensive.

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#65

Post by benj111 »

husam212 wrote: post #56
hooby wrote: post #47

The thing I see not mentioned in the article/video, is how the wheels can tilt/turn/angle - without needing a CV joint again. The designs seems to cover all the motion of the wheel in the suspension - but I don't see how this could accommodate steering. Is this for back wheel drive only? Curiously the animations shown in the video, show the uni wheel used in the front of a front wheel drive car - but without ever sho…

Maybe the motor is supposed to turn with the wheel, that doesn't sound like a good idea.

Why not?

You'd have an added complication of making the shock absorber the pivot point, and attaching the motor to the top point. Or having a separate pivot point where the motor or wheel can slide up and down.

This does raise the question of why not just attach the motor straight to the wheel.

The standard response to that is a hand wavey "unsprung mass". But has it actually been tried and shown to be an issue?

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#66

Post by benj111 »

nabilhat wrote: post #51

Worth noting, placement at the wheel is somewhat arbitrary. There's nothing to prevent this contraption from working the other way around and being mounted at the chassis instead, aside from squeezing out every bit of space optimization. Axle support would be a concern either way. Controlling deflection of the drive axle adds a structural requirement, certainly a well supported bearing close to this device. The gears…

It's trying to compete against a CV joint and gear box.

That seems like an easier sell.

I'm not sure if we're talking past each other but you wouldn't need an axle to deflect. The motor drive could attach directly to the 'uni wheel' which is in turn connected directly to the wheel. If you're talking about the motor drive shaft, then surely you'd just be moving thrust bearings from the gearbox to the motor (if motors don't already have them)

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#67

Post by semi-extrinsic »

neuralRiot wrote: post #11
thedrbrian wrote: post #3

So we could have a slightly bigger inside to the usual EV SUV. woo

Bigger inside than modern SUVs? What does people transport? How many people ride regularly? What size are people?

I drive a small petrol powered MPV. It has a luggage capacity of 710 liters in the trunk with 5 passengers, 160 liters with 7 passengers, or 1900 liters with 2 passengers. Moreover the trunk is square, so I can go to Ikea and buy a whole new kitchen and fit it in the trunk. The cargo loading capacity with 5 adult passengers is 450 kg. It has a towing capacity of 1650 kg. It also has a large roof box. New price was around $30k depending on trim level.

Now show me a modern EV that has similar specs, and you are talking about a large SUV that's up around the $100k price range.

It's a simple fact that while modern EVs are often styled as SUVs, the inside is comparatively tiny since the battery pack takes up a lot of space.

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#68

Post by benj111 »

jacquesm wrote: post #38
grogenaut wrote: post #26

Earlier quoted context omitted.

unsprung weight I believe is also a big issue with hub motors esp as you get up to car size at speed

It is the issue for in-hub motors. Solve that one and the world will beat a path to your door and shower you with money.

Have you got a source. Everyone mentions this, but I've never come across anyone trying and failing.

Motor scooters have unsprung motors, the motor is a significant proportion of the mass.

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#69

Post by Beijinger »

seltzered_ wrote: post #18

FWIW, there was recently a now-defunct car company (Lordstown motors) that utilized an in-wheel motor from the company Elaphe ( https://in-wheel.com/en/technology/#in-wheel-motor-technolog... ) I think the tradeoff is between more flexibility & fewer parts (no cv joints) but possibly more rolling resistance. But watch the video, this uni-wheel thing is different. It isnt an in-wheel motor, more of a cv-joint alternat…

Is Lordstown defunct?

As far as I know, this Czech company uses in-wheel motors:

https://spartan.mwmotors.cz/ev-traditional-technologies/

Re: Hyundai Uni Wheel electric drive system could revolutionize EV design

#70

Post by Beijinger »

jacquesm wrote: post #38
grogenaut wrote: post #26

Earlier quoted context omitted.

unsprung weight I believe is also a big issue with hub motors esp as you get up to car size at speed

It is the issue for in-hub motors. Solve that one and the world will beat a path to your door and shower you with money.

You can buy a car powered with in-wheel motors here:

We have developed the first production car to use in-wheel hub motors. https://mwmotors.cz/luka-ev/

This car maybe too, as far as I understand it. A Russian UAZ on steroids: https://www.youtube.com/watch?v=RCOf_33C1qc

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