eCVTs on EBikes

[stancecoke]

To make one rpm of the wheels the outer motor then has to rotate through every tooth it normally does, plus it has to undo all the teeth the center motor driving the outside ring in reverse took up.

There is no variability on the carrier speed and on the sun gear speed.
If you want a cadence of 70/min, the carrier has exactly the speed that the fix ratio of the belt 1 defines. If you want to ride 15 mph, the sun gear (and with this the motor 2) has exactly the speed that is needed to turn the rear wheel with 15 mph.
The only variable thing is the speed of the ring gear. The motor 1 has to be controlled exactly to the speed that leads to a cadence of 70/min and the bike speed of 15 mph. We could calculate the needed ring gear speed easily, if we would know the exact teeth numbers of all gears... (planetary, belt, sprockets)
The motor 1 will have to work in generator mode or has to turn backwards, as the sum of the torques has to be zero.

 

[lnanek]

Hmm, maybe that's why it's called the torque motor and not the speed motor. Since we can vary the torque it experiences. The earlier examples even had a case where it was going forward but experiencing negative torque:


Too bad that means it can't always be in the most efficient RPM for the motor, though.

 

[stancecoke]

Some more detailed information is available on the Gobao system now:

"Die Zukunft des E-Bikes ist stufenlos": Wie ein Toyota-Getriebe das E-Bike revolutioniert

Schalten war gestern! Gobaos neuer E-CVT-Antrieb schiebt dich mit 150 Nm vollautomatisch den Berg hoch. Ein Automatikroller mit Mega-Muckis oder die E-Bike-Revolution? Wir sind den Prototyp gefahren!

www.bike-x.de

Gobao also combines two electric motors with a planetary gearbox. According to the schematic diagram, rider and motor power are fed together into the ring gear, while the control motor regulates the gear ratio via the sun gear. The output is routed through the planet carrier.

So the advantage, that the main motor uses the gear to run in an efficient speed range is kept.

 

[Alon-ChargeBike]

Some more detailed information is available on the Gobao system now:

"Die Zukunft des E-Bikes ist stufenlos": Wie ein Toyota-Getriebe das E-Bike revolutioniert

Schalten war gestern! Gobaos neuer E-CVT-Antrieb schiebt dich mit 150 Nm vollautomatisch den Berg hoch. Ein Automatikroller mit Mega-Muckis oder die E-Bike-Revolution? Wir sind den Prototyp gefahren!

www.bike-x.de

So the advantage, that the main motor uses the gear to run in an efficient speed range is kept.

This topology is called input split, the disadvantage is that now the ratio motor must match the torque of the rider + the assist motor

 

[stancecoke]

now the ratio motor must match the torque of the rider + the assist motor

We are looking forward to see your solution for a hub motor system