This 250W mid -drive is promoting itself as having an revolutionary and patented “Always Variable Transmission/CVT”. Let’s check out what little data is offered…
Revonte-ONE, from Finland
Usually, I’d not be all for a brand new 250W drive unit, however…this one marketed itself as having an revolutionary CVT transmission. By limiting the quantity of enter energy that’s allowed on “street-legal” ebikes for many European ebikes, some very sensible engineers have spent a substantial quantity of effort and time attempting to determine find out how to get the very best attainable wheel-torque from the modest allowable inputs…
Lavelle ebikes within the UK was impressed by the Revonte system, and so they have contracted to make use of this intelligent mid-drive.
The Revonte-ONE system
Though Switzerland and Austria enable a spectacular 500W in a avenue authorized ebike (Dankeshoen!), nearly all of European ebikers should wrestle together with a modest 250W of enter. I don’t know whether or not I needs to be disillusioned or offended, however…I’ve taken dumps that used greater than 250W of power…(I already use 1500W each time I experience, and I plan to improve to 2500W as a result of I’m a degenerate power-hungry addict)
I don’t approve of ebikers who drive recklessly at high-speeds and endanger pedestrians, however…if you wish to exchange a automotive with an ebike, and you’re carrying a toddler together with two baggage of groceries…how a lot energy do you have to be allowed to have if you deal with a steep uphill in your ebike? (for those who experience safely, the right reply is 2500W…or extra)
If this was simply one other weak 250W Euro ebike, I wouldn’t waste my time writing about it. Nevertheless, their declare of utilizing a CVT is intriguing. I’ve emailed the corporate, and so they declare the system is so distinctive, it was patentable. I haven’t discovered the patent but, however I’ll maintain trying…
What can we moderately speculate in regards to the Revonte CVT, from the small quantity of knowledge they’ve reluctantly revealed? They state that the guts of the CVT is a planetary gear-set. That is very plausible, since planetaries are a compact and strong method to enable an electrical motor to spin many occasions sooner than the mid-drive output.
Most electrical motor designs have effectivity curves that work properly round 3,000-RPMs, however the rear wheel of a 26-inch ebike is touring at 26-MPH when it’s spinning at solely 336-RPMs. That may require roughly a 9:1 discount in RPM’s between the motor and the wheel. A planetary gearset is a sturdy, compact, and reasonably priced method to accomplish this.
The Revonte system solely permits a 250W enter. Despite that, they produce a decent and spectacular 90-Nm of output torque.
So…how do they accomplish having a “Always Variable Transmission”? I’m a fan of mechanical units, and I’ve seen crane transmissions that used two motors coupled by a planetary gear-set. One motor offered the absolute best torque on the slower speeds, and the second motor offered a a lot greater pace when the crane wanted to boost or decrease the hook quickly when it was un-loaded.
Revonte answered my emails however stated they don’t seem to be able to reveal the main points simply but. It’s virtually sure that the principle motor drives the solar gear of the planetary gear-set (see the graphic above), so what does the secondary motor do? I imagine it drives both the sting of the ring gear, or it drives they fringe of the service plate that anchors the axles of the three planet-gears…both choice would supply a variable output because it pertains to torque and pace.
In the end, anyone will tear one aside and submit pics on the internet, and…with their permission, I’ll re-post them right here. (together with a hyperlink to any patents)
I want Revonte the very best of luck. Offering 90-nM from solely 250W is spectacular, plus the variable transmission declare is intriguing. I need to know the way they completed this, and I’ll submit any discoveries right here…
Written by Ron/spinningmagnets, February 2020