Ah no, the little g310 motor is not an option for regen braking, without an extra set of thrust bearings to counter the axial force from the helical gears. https://www.youtube.com/watch?v=KDuZFQy_Q-I
I was wanting to do this as the front motor and maybe later convert to a clutchless planet gear carrier for regen, or consider the ezee with off the shelf fixed carriers available, but 3.8 vs 2.3kg 🤔 how hard could it be to add thrust bearings... #regenBraking#eBike
@enobacon i have several of those bafangs with helical gears that I got for a song last summer. I was going through the exact same thought process a couple weeks ago. I gave up on it as needlessly complicated, but if you can sort it out please post details!
@Karstan is there not enough space for a second set of thrust bearings, no place for them to bear against? Given the size, weight, side cable exit, better fit in the dropouts, low noise, it's exactly what I want except the regen ability. Like if somebody is going to build a new carrier, is there a place to put them? I'm not clear on where the clutch mechanism is in here though, is it in the black axle bit or under the three planet gears? https://youtu.be/e2oS5HORtFk?t=110
@enobacon It's part of the exterior housing as I understand it. See attached photo where I circled in orange. (My motors are sightly different G320s, but the differences are minimal.)
I'm not clear where the thrust bearings would need to go to make it work? On the outer edge of the planetary gears? In my 2nd photo, the current/existing bearings are underneath, then would the new one go on top? If so, maybe if you machined down the width of those outer teeth there would be room?
@Karstan Yeah I guess you would need a redesign to that black plate/shaft to hold the thrust bearings (maybe no change to the gears, if there is clearance above the plate) and then to weld the clutch or replace/fix that outer geared bit somehow.
@enobacon I've been looking at this bafang g3xseries regen issue again this week for some reason. I think I've worked it out.
Remove the clutch/bearing/gear, and weld the exterior to the interior so it doesn't spin
shave down the "cups" off the interior plate on the axle thing. (Where the pins that serve as axles for the 3 gears slot in.) This will make room for thrust bearings
@enobacon 3) replace said 6mm pins above with some slightly longer ones to compensate for step 2 above (https://www.mcmaster.com/91595A458)
4)Add some thrust bearings to the top of the gears after removing the "cups" underneath the axle plate https://www.mcmaster.com/7806K58
5) There's only 3.5 mm of space in between the bottom of the axle/plate and the bearing surface, so the thrust bearing washers will need to be replaced with these https://www.mcmaster.com/3088A063
@Karstan they do have some that lock two ways on the flatted axle but it would be nice to get some engagement like the splined thing on the gmac and just use round axles (or why can they not be machined down that 1mm that sits in the fork.)
@enobacon The thrust bearings have a pretty decent capacity I think? Dynamic 270 lbs, Static 410lbs. x3 bearings. And this is just the axial thrust which I imagine is significantly less than the torque?
@Karstan it could be that nothing in the thrust bearings compares to the limitations of the torque arm, but something might be pressed into the casing one way, or some other trick where the reverse load pops it out. Overall it sounds like you're on the right track. I also wonder if the added friction might be a drag vs having a little play so the reverse bearings aren't touching, but then how much can the travel back and forth + impact cause fatigue.
@enobacon I'm bummed. I tackled this project again primarily because I was hoping to figure out a way to side-mount these to use on a reverse trike project. But it'd unfortunately require completely re-engineering them. :/
I'm just going to use an old direct drive motor on the rear wheel I think. Before tackling the Bafang hub idea, I was looking at repurposing some wheelchair wheels. But I couldn't figure out an easy way to retrofit brakes onto them. So I ordered some 15mm axle hubs off ebay.
@enobacon Yeah, not just a different axle. The axle/plate and attachment points would have to strengthened significantly I think. There's just not enough material there or room to add them. It's actually and amazingly well-engineered little motor. But engineered for a very specific purpose.
@Karstan I can't find the name now but there was a freakbike builder space in inner SE ~2018. Probably somebody at Thursday Night Ride knows what's up lately.
@Karstan keeping the original thrust bearings there though? The other thing would be where is the reverse thrust force is transferred to, or if friction and heat in that direction/component somehow become a limitation.
@enobacon yup, same thrust bearings at the other end.
Yeah, it could be an issue potentially? Thrust in that direction would be into the axle plate which is held in place by three screws. But the other side of that plate rests against the axle bearing when the motor casing is reassembled.
@enobacon nope, no thrust bearings other than those original 3. That axle bearing could potentially fail potentially? But it's held in place by the casing and backed up by the fork and axle nut. It's not goimg anywhere. Though easy enough to replace it, or even add a thrust bearing between the outer casing and the axle plate. There's just enough room for a needle bearing.
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