Spur gear retro-direct
- Thread starter Miles
- Start date
HAL9000v2.0
10 kW
HAL9000v2.0
10 kW
Miles said:
Just retro-direct. But it will be nice to have it all.
HAL9000v2.0
10 kW
Didn't read comment, I was amused with the picture so I assumed that grey is output shaft.
HAL9000v2.0
10 kW
Yep I've thought about this.
Guts of a bafang-ish motor: The freewheel is keyed on the axle, when the cog on the motor's bell turns, it pushes the spur gears that locks the freewheel, so power gets transmitted to the outside ring. The gear down is as if the motor's bell gear was driving the ring directly. If the motor were made to turn the other way, the freewheel would disengage and allow the spur gears to spin around.
But if one were to add a second freewheel, inverted in rotation compared to the first and with two gear steps using gears like the ones in the P2-A, then reversing the motor would lock this second freewheel and drive the bike onwards with greater reduction.
So it seems fairly doable, but probably not without dumping a lot of money. Also In this form factor, getting the width to fit well between drops or fork ends seems like it would be the main issue, but also retro direct gearing prohibits reverse, and seems it would be easy to break something by forcing it.
Guts of a bafang-ish motor: The freewheel is keyed on the axle, when the cog on the motor's bell turns, it pushes the spur gears that locks the freewheel, so power gets transmitted to the outside ring. The gear down is as if the motor's bell gear was driving the ring directly. If the motor were made to turn the other way, the freewheel would disengage and allow the spur gears to spin around.
But if one were to add a second freewheel, inverted in rotation compared to the first and with two gear steps using gears like the ones in the P2-A, then reversing the motor would lock this second freewheel and drive the bike onwards with greater reduction.
So it seems fairly doable, but probably not without dumping a lot of money. Also In this form factor, getting the width to fit well between drops or fork ends seems like it would be the main issue, but also retro direct gearing prohibits reverse, and seems it would be easy to break something by forcing it.
Mathurin,
Good thinking. I've considered an epicyclic retro-direct, too, but my idea is a bit different to yours, and not in a hub motor. Still working on it...
Also, you might be interested to have a look at this:
http://v3.espacenet.com/publicationDetails/originalDocument?CC=WO&NR=2008088169&KC=&locale=EN_ep&FT=E
Good thinking. I've considered an epicyclic retro-direct, too, but my idea is a bit different to yours, and not in a hub motor. Still working on it...
Also, you might be interested to have a look at this:
http://v3.espacenet.com/publicationDetails/originalDocument?CC=WO&NR=2008088169&KC=&locale=EN_ep&FT=E
