this post was submitted on 02 Dec 2023
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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.
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.
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.
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.
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 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.