I was searching for different types of gearing set-ups last night for a new way to power a board and I started thinking about how mopeds have a type of CVT that could be used. I searched for a electric longboard with CVT and this came up:
The Voltige Board
OMG if this is really going to be comming to market… wow…
it’s interesting. I wounder how good of a product they end up making.
This is somewhat limited in the current design to 1wd. And at that, your not going to have very good performance already. Don’t know if the CVT will really be noticeable.
In terms of performance, I can’t imagine this beating a dual drive setup with the same sized motors.
Since the CVT is not for performance in this case, there is another useful use, which is range. It will likely be the best range possible with a single motor.
Also, think this has been talked about on here before.
These guys are local, tried meeting up with them, but no go… so in the meantime it’s vaporware
Why can’t this be used for 2WD? Surely you’d add a the 2nd motor on the other side and have the unit wider?
Genuinely asking as I’m not familiar with how CVTs work… Yet
Complexity and space restraints would make it harder. In a car, theres one cvt transmission. So what do you do? Either each motor gets it’s own CVT transmission or you do what cars do and split 1 motor. Either way, a lot of work. 1wd CVT is doable, as seen here.
For anyone who doesn’t know what a CVT is, this is a helpful video.
no brakes possible. no regen.
using a single spring to control the outer variator and relying just the belt tension sounds like a terrible idea. for one, even a kevlar belt will wear quickly, and what happens when the springrate goes out of spec?
a car cvt uses hydraulic or mechanical force to adjust the variators and belt ratio.
That’s a definite deal breaker
or i should say i’m pretty sure it has no brakes. cant imagine how brakes would work with a cvt…or no i can imagine it and they would suck.
Esk8 without brakes, sounds scary.
What makes you say there would be no breaks it seems like it could have brakes no problem, and it looks like a simple fix to make it dual drive. The linear motor that pulls towards our backwards, it’s positioned on the one side. Just position it in the middle and add a drive to both sides.
ok, hummie, I got it, two motors at two different kv’s and/or two different gearing ratios, effectively producing a software 2-gear eskate where the power can be focused to one motor or the other depending on torque and speed requirements and increase overall efficiency…this would retain the break and regen and produce something similar too the CVT but only in steps…
A lot of application relays in springs, all of the UTV and quadbikes use centripetal force to change the gearing and the belts last pretty long
But what kills is efficiency, this type of CVT waste a lot of energy on heat due to friction, in the BAJA SAE team that I participated we got a peak of 60% maximum power transfer, with an average of 40%, for a battery powered vehicle is a no go, only if they manage to improve that
Regarding breaks, they can put a hub motor at the front that could be used only for breaking. But it makes that esk8 even more complex.
Can someone please explain why breaks wouldn’t work with this? I don’t see how they suddenly don’t work in this setup.
It’s my opinion that brakes would work fine - if you can transfer power one way you can transfer it the other. And in fact, with clever software you could even tune the brakes for more or less regen based on your preferences. (think of the gas pedal in a 2018 Leaf). My Prius has CVT and regen.
But @Pedrodemio nailed it - the problem is efficiency.
I think there’s space for a simple electronically controlled motorcycle-style 2-speed transmission if you could figure out how to get it to shift without jarring too much. This is a great term project for some ME student (hint).
(Edit) Ok, I just watched the video. The way they did the CVT is quite clever and easy to reproduce. I’d say a week in the shop to have a working prototype. So we can test this design even if it the product is vapour.
Thinking about this 2 speed gearing, it should be possible to fit a planetary gear inside the wheel pulley, but it’s going to be expensive since the gears is gonna be tiny and you would need lots of planets to manage the stress. Also some form of locking/unlocking the gear set
As a proof of concept or just because it’s fun it’s doable, but as this same discussion has been done a lot of times, for most use cases of our boards this is not needed due to peak torque at low rpm of electrical motors
One place this could works is with EMTB, never ridden one so I can’t say if the massive setups we see here lack torque for some of the serious climbs out there, but there is way more space to fit this mechanism
Very interesting topic I’ve spoke of a transmission before, but I was thinking something different with two different gear sizes abs the motor shooting in the same way to each gear while moving side ways as well