171–180 of 192 posts
This wouldn't have worked for ICE cars, because in order to have a reasonable range of up-and-down movement the gear ratio needs to be quite high (ie, the pinion gear has to be much smaller than the ring gear). It's 6.2:1 in the article, about 2x what's appropriate for the top gear on an ICE car.
My first question, on seeing a picture of the drive, was how this allowed the wheel to be turned for steering - this is, after all, the difficult part of driving the front wheels (if you are not using an in-hub motor) and is why a CV joint, and not just any universal joint, is needed (when turning sharply, the wheel axis is nowhere near parallel to the motor axis.) Neither the article nor the video mentioned steering…
I think this would make most sense with an axial flux motor. That’d keep the package quite compact.
I’m guessing the camper changes mentioned could also be handled by the motor pivoting up and down as well. But I can’t say for sure if that makes sense.
I love innovation. There still needs to be a CV joint to allow steering, but short of hub motors[1] There isn't much you can do about that. What I would be interested to see is how lubrication works. Do you think they just have a bunch of oil in the bottom and rely on centrifugal force to fling it to the ring gear? Then let surface tension transmit it to the sun gear? [1] They are heavy and heavy wheels affect ride q…
Naw, because if you look closely in the video you can see that the motors turns with the wheel. With small EV motors that’s not unreasonable.
Presumably the motor is free to tilt up and down a bit as well to deal with changing camber.
> but short of hub motors[1] There isn't much you can do about that.
I mean, it is pretty much a hub motor that has been decouple in the vertical motion so it doesn’t contribute to unsprung mass, and with a good reduction gear as a bonus.
Earlier quoted context omitted.
Why only high performance though. A motor per wheel simplifies everything. No diff, no CV joints, you don't need this, just a simple planetary gearbox. You gain space, lower manufacturing costs (theoretically, assuming multiple motors doesn't offset the other cost reductions, although as you could base a 2wd and 4wd high performance version on the same motor, that's an even harder case to make).
Everyone says "unsprung mass" but you also have to provide cooling without ingesting all the dirt and water off the road. It's not that simple.
My first question, on seeing a picture of the drive, was how this allowed the wheel to be turned for steering - this is, after all, the difficult part of driving the front wheels (if you are not using an in-hub motor) and is why a CV joint, and not just any universal joint, is needed (when turning sharply, the wheel axis is nowhere near parallel to the motor axis.) Neither the article nor the video mentioned steering…
In the video you can see the motors turning with the wheels. So there’s no problem there at all. I think this would make most sense with an axial flux motor. That’d keep the package quite compact. I’m guessing the camper changes mentioned could also be handled by the motor pivoting up and down as well. But I can’t say for sure if that makes sense.
Earlier quoted context omitted.
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
Earlier quoted context omitted.
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
That Luka has some pretty interesting tech and is so sharp-looking. I hope it's a massive success.
Earlier quoted context omitted.
Hub motors make wheels quite heavy, which means that there's more unsprung mass [1] in the vehicle, making it less responsive under acceleration/braking and more noisy and sensitive to vibrations. They're common in electric scooters, bikes and bicycles though. [1] https://en.wikipedia.org/wiki/Unsprung_mass
newer designs are silent, weigh about 2lbs or a little under a kilo, can produce upwards of 100nm torque at 1000w.
Earlier quoted context omitted.
newer designs are silent, weigh about 2lbs or a little under a kilo, can produce upwards of 100nm torque at 1000w.
1kW isn't going to suffice. Car motors are >100kW.
With all those extra gears, the efficiency should be comparable? Would only work for real wheels of course.