Ecobogan
100 W
That being no changing the configuring the internals. Changing up or down yes, all being well!
Downhill project motorcycle transmission
- Thread starter Ecobogan
- Start date
LightningRods
1 MW
I think this is the way to go if all of the engineering problems can be overcome. I don't see why the losses from a constant mesh transmission should be so great as to prevent using one. Isn't the Rohloff Speedhub constant mesh? If the constant mesh transmission is the right power capacity for the motor it's connected to it should be very efficient and reliable.
I'm excited to see how this build turns out!
I'm excited to see how this build turns out!
crossbreak
1 MW
sure. it works in a motorcycle so power is fine if it's in the right rev range. The drag is also acceptable...if you turn it by hand it does not have a lot of friction you could feel.
You could still reduce friction by adding needle bearings. but that adds cost to a low cost product.
Only real drawback i see: Power to weight ratio is low compared to a planetary drive. That is simply a question of cost. If we think about automatic car transmissions (most are planetary i guess). The cost question is also something one would consider soluble.
BTW: The rohloff is constant mesh as most IGHs. not for all gears this is true (many freewheels), but for most. Using IGH sadly denies regen, due the freewheels
A transmission like an automatic car transmission (planetary) with the size of a IGH, but with dog clutches instead of freewheels would be what i would favor
@Ecobogan: throw out gears is something you can still do later
i'd get it work right before doing that. There once was a thread just about this topic from an Italian guy here. He used a 80-100 motor and shift the dogs by RC servo. Maybe I can dig out that thread and post a link.
You could still reduce friction by adding needle bearings. but that adds cost to a low cost product.
Only real drawback i see: Power to weight ratio is low compared to a planetary drive. That is simply a question of cost. If we think about automatic car transmissions (most are planetary i guess). The cost question is also something one would consider soluble.
BTW: The rohloff is constant mesh as most IGHs. not for all gears this is true (many freewheels), but for most. Using IGH sadly denies regen, due the freewheels
A transmission like an automatic car transmission (planetary) with the size of a IGH, but with dog clutches instead of freewheels would be what i would favor
@Ecobogan: throw out gears is something you can still do later
i'd get it work right before doing that. There once was a thread just about this topic from an Italian guy here. He used a 80-100 motor and shift the dogs by RC servo. Maybe I can dig out that thread and post a link.Ecobogan
100 W
I'm not too worried about the friction and as mentioned I won't be removing any gears, as tempting as it may seem, probably ever.
I would have thought that generally auto boxes were heavier and had higher friction losses than the equivalent manual. Seemed to be the case with the old school American V8's.
I'd sure be interested in seeing how the Italian guy did his servo shifting. I was thinking of a BMX brake lever under the rear brake cable operating upshifts and shifting down at the gear lever via one's foot.
Have to get a stack of 5183 tig rods, that being the choice for welding 7005 to 7005 as in the swingarm and welding 7005 to 6061 as in the frame. Spoke to an affable heat treating chap on the frame and he seems to think annealing only is the way forward. Partly due to the two different materials in the frame.
The swingarm is, in my opinion under the most load and perhaps could be hardened because it is only of 7005 and may need to be.
I'll certainly be re asking a few questions before the process takes place.
I've over engineered the stress points in the frame and should be ok with annealing.
The compression and tension loads in the swingarm may need some fish plating and hardening.
More calcs and research.
Thanks guys
I would have thought that generally auto boxes were heavier and had higher friction losses than the equivalent manual. Seemed to be the case with the old school American V8's.
I'd sure be interested in seeing how the Italian guy did his servo shifting. I was thinking of a BMX brake lever under the rear brake cable operating upshifts and shifting down at the gear lever via one's foot.
Have to get a stack of 5183 tig rods, that being the choice for welding 7005 to 7005 as in the swingarm and welding 7005 to 6061 as in the frame. Spoke to an affable heat treating chap on the frame and he seems to think annealing only is the way forward. Partly due to the two different materials in the frame.
The swingarm is, in my opinion under the most load and perhaps could be hardened because it is only of 7005 and may need to be.
I'll certainly be re asking a few questions before the process takes place.
I've over engineered the stress points in the frame and should be ok with annealing.
The compression and tension loads in the swingarm may need some fish plating and hardening.
More calcs and research.
Thanks guys
crossbreak
1 MW
here http://endless-sphere.com/forums/viewtopic.php?f=28&t=42262
Ecobogan
100 W
Cheers mate, most informative. Going to tig the frame and swingarm this weekend then just need THE MOTOR!!!
Ecobogan
100 W
Looks like the old Lincoln tig has shat itself so the project is on hold for now. Have got the chain idlers sorted out and JUST NEED A BLOODY WELDER. Going to be weeks till I can go forth and buy another, so not much can happen till then.
crossbreak
1 MW
maybe rent one? when i come to my local weld shop with a piece that is completely ready to weld, they dont talk much..price is always reasonable $$
Ecobogan
100 W
Could rent one or get another fabricator to sort it out but I'm way too egotistical for that. Do need a tig for down the track anyway,and a mill, lathe,laser cutter, plate roller etc!
In the meantime I've re done the lower left side swing arm spar in a solid piece of 6061. Yes I realise it will be heavier but will be worth the weight cost with the bikes impact loads at higher speeds than what the stocker was designed for. The lower spars being under tension so welding to a solid piece is preferable.
I'll possibly be lengthening the swing arm to aid stability so this will help also. So fixing the chain tensioner and idler should be sorted this weekend.
Thus far have been using the mig to tack it all together which is fine until I GET A BLOODY TIG which works fine. Anyway still more that can be done with zero cash input which is where it's at. Did I mention I need a new tig?
Still eating on the motor, controller and throttle, been over 2 months. He did say astroflight can be a tad slow off the line.
Pics coming soon
In the meantime I've re done the lower left side swing arm spar in a solid piece of 6061. Yes I realise it will be heavier but will be worth the weight cost with the bikes impact loads at higher speeds than what the stocker was designed for. The lower spars being under tension so welding to a solid piece is preferable.
I'll possibly be lengthening the swing arm to aid stability so this will help also. So fixing the chain tensioner and idler should be sorted this weekend.
Thus far have been using the mig to tack it all together which is fine until I GET A BLOODY TIG which works fine. Anyway still more that can be done with zero cash input which is where it's at. Did I mention I need a new tig?
Still eating on the motor, controller and throttle, been over 2 months. He did say astroflight can be a tad slow off the line.
Pics coming soon
Ecobogan
100 W
That'd be waiting on the motor . Not planning to eat on it at this stage but life can take some funny turns
LegendLength
100 W
I think this is a great build and absolutely the right way to go. I have done intensive searching myself for appropriate transmissions and always come up empty. I have looked at scooter transmissions, go karts, nuvinci-style, and even small car transmissions (e.g. 500 cc cars). All of them have issues, mostly lack of clutch, too much weight and poor availability & price.
The RPM range and power output of a 2 stroke is perfect for just replacing the piston assembly with a sideways mounted motor (like you have planned to do). The weight is a little high but they do make them solid for a reason. If weight could have been shaved off the transmission for dirtbikes you'd think they would because weight is a very important sales point for 2 strokes.
I suggested a similar setup in the past and got the same kind of responses: "You only need a 3 speed", "A direct drive is better", etc.. That would be true if there were suitable 3 speeds to buy (that have a clutch). Also direct drives are horribly inefficient up steep trails and throwing more power at the problem makes the system much heavier.
Good luck with the build. It will be ground breaking if you can get it going. Maybe it will spur some manufacturers to produce solid, lightweight gearboxes for e-bikes finally even though there has been a glaringly obvious need for years.
One other thing, on the Nuvinci site they had a 'coming soon' section claiming they have lightweight transmissions for ATVs and smaller vehicles. I could never find any info about it but that was years ago so might be worth having a look to see if they have progressed in that area. I'm sure they would be expensive but if they are light enough and can handle the power it may be worth it.
The RPM range and power output of a 2 stroke is perfect for just replacing the piston assembly with a sideways mounted motor (like you have planned to do). The weight is a little high but they do make them solid for a reason. If weight could have been shaved off the transmission for dirtbikes you'd think they would because weight is a very important sales point for 2 strokes.
I suggested a similar setup in the past and got the same kind of responses: "You only need a 3 speed", "A direct drive is better", etc.. That would be true if there were suitable 3 speeds to buy (that have a clutch). Also direct drives are horribly inefficient up steep trails and throwing more power at the problem makes the system much heavier.
Good luck with the build. It will be ground breaking if you can get it going. Maybe it will spur some manufacturers to produce solid, lightweight gearboxes for e-bikes finally even though there has been a glaringly obvious need for years.
One other thing, on the Nuvinci site they had a 'coming soon' section claiming they have lightweight transmissions for ATVs and smaller vehicles. I could never find any info about it but that was years ago so might be worth having a look to see if they have progressed in that area. I'm sure they would be expensive but if they are light enough and can handle the power it may be worth it.
Ecobogan
100 W
I believe so too, and in part because it's much easier to run a gutsy final drive. If push bike gear could handle a regular 5-10kw flogging then I mightn't have bothered.
The gearbox is certainly on the over kill side of the scale but, as I've mentioned, this project needs to be able to be added to and modified further down the track(so to speak). If it ends up more dirt bike than downhill that'll be ok, ridden on dirt bike trails of course.
My point is that I just want to build a high performance electric downhill and maybe 9kw peak power will be enough, maybe not, I don't know I haven't ridden one before, there virtually is no such thing to test ride. In my mind using this small bore trans allows further mods without breaking etc etc
Got myself another tig welder the other day, coincidently it's utterly identical to my old Lincoln 250 which mysteriously shat itself, for $200 which is nearly a bargain. So now I have spares, awesome.
Anyway pulled off some a-class super shit welds using thoriated electrodes and some un identified filler rods from the bowels of my shed just to have a crack. Which is what they did. Some 5183 filler rods and zirconiated 3.2mm electrodes are on the way which is what's needed for the 6061 and 7005 combo, not to mention practice practice practice. I have some help I can call on if I get scared.
The likelihood of needing to lengthen the swing arm is a real one so the other day I sacked my dense idea of using the standard swing arm spar and replaced the whole lower spar with a shaped solid piece of 6061 on the sprocket side. This will be made as light as possible but will still be heavier than what was there before. Being able to take higher tension loads and far easier fixing of shaft brackets made this an obvious move....for the time being!
Finally got the chain tensioners sorted out and brackets made.
Thanks for the response mate and I really need to post some more pics
The gearbox is certainly on the over kill side of the scale but, as I've mentioned, this project needs to be able to be added to and modified further down the track(so to speak). If it ends up more dirt bike than downhill that'll be ok, ridden on dirt bike trails of course.
My point is that I just want to build a high performance electric downhill and maybe 9kw peak power will be enough, maybe not, I don't know I haven't ridden one before, there virtually is no such thing to test ride. In my mind using this small bore trans allows further mods without breaking etc etc
Got myself another tig welder the other day, coincidently it's utterly identical to my old Lincoln 250 which mysteriously shat itself, for $200 which is nearly a bargain. So now I have spares, awesome.
Anyway pulled off some a-class super shit welds using thoriated electrodes and some un identified filler rods from the bowels of my shed just to have a crack. Which is what they did. Some 5183 filler rods and zirconiated 3.2mm electrodes are on the way which is what's needed for the 6061 and 7005 combo, not to mention practice practice practice. I have some help I can call on if I get scared.
The likelihood of needing to lengthen the swing arm is a real one so the other day I sacked my dense idea of using the standard swing arm spar and replaced the whole lower spar with a shaped solid piece of 6061 on the sprocket side. This will be made as light as possible but will still be heavier than what was there before. Being able to take higher tension loads and far easier fixing of shaft brackets made this an obvious move....for the time being!
Finally got the chain tensioners sorted out and brackets made.
Thanks for the response mate and I really need to post some more pics
Drum
100 W
Looking forward to seeing more progress on this one.. I'm following it with interest. I think it is a set-up well worth exploring.
My build has a big motor and single reduction ratio, but I can see that a smaller motor with several ratios has some advantages.
As to weight, the BHT motor I am using weighs just over 5kg, so if you can get a system running with similar power at the same weight, and 5 ratios, together with a simple and strong single ratio final drive, it will certainly be interesting!
Good luck with the welding. Getting the right tungstens and filler rods will help a lot. I mostly weld stainless on DC TIG, and whenever I weld Alu on AC I need to practice a bit before it starts coming out smooth.
Best wishes,
Drum
My build has a big motor and single reduction ratio, but I can see that a smaller motor with several ratios has some advantages.
As to weight, the BHT motor I am using weighs just over 5kg, so if you can get a system running with similar power at the same weight, and 5 ratios, together with a simple and strong single ratio final drive, it will certainly be interesting!
Good luck with the welding. Getting the right tungstens and filler rods will help a lot. I mostly weld stainless on DC TIG, and whenever I weld Alu on AC I need to practice a bit before it starts coming out smooth.
Best wishes,
Drum
Ecobogan
100 W
I think I'm going senile, just re read a post of mine a few back and I just said the same thing twice, nearly verbatim on the swingarm. Oh well lucky I really shine in other areas.
Thanks Mr Drum, the drive unit itself should come in at about 5kg maybe a tad more with oil and side cover plates. Like most welders (the people that is) we run migs almost exclusively and dc stick on site. With relative success I ac tig welded the plenum chamber and custom aluminium ductail on my sportsbike. As you mentioned it's the personality of the material not the principle that takes some getting used to.
There will be some taking it easy and checking for cracks before doing anything too daft that's for sure!!
I just received a message from Matt that the motor, controller and throttle is now on its way-wooooooohoooooo.
I do however have a question for you lads and ladies, two in fact. The first being that i'm looking to purchase the batteries fairly soon. I was considering a bunch of eight 5000mah 6s hobbyking/turnigy's running four groups of two in series then paralleling them giving 20ah and 880whr's. This at about $600 seems to be reasonable. I did stumble across the 22000mah 6s Tattu that would work out to be about the same. Also jonescg custom packs. Any thoughts kids?
Also is regen braking a suitable option as a rear brake instead of a disc rotor? If I could do away with a rear brake altogether that'd be nice. This wouldn't be so much to get a recharge but to negate having to build a disc set up in board of the drive sprocket, do able but a pain if can be avoided. The drive sprocket is mounted as far out as possible for swingarm clearance and countershaft sprocket alignment. May have to get Matt involved here.
Am out of the workshop this weekend unfortunately but next week is dedicated downhill time, so yes it will be welded up with ensuing pics, I promise.
Cheers
Thanks Mr Drum, the drive unit itself should come in at about 5kg maybe a tad more with oil and side cover plates. Like most welders (the people that is) we run migs almost exclusively and dc stick on site. With relative success I ac tig welded the plenum chamber and custom aluminium ductail on my sportsbike. As you mentioned it's the personality of the material not the principle that takes some getting used to.
There will be some taking it easy and checking for cracks before doing anything too daft that's for sure!!
I just received a message from Matt that the motor, controller and throttle is now on its way-wooooooohoooooo.
I do however have a question for you lads and ladies, two in fact. The first being that i'm looking to purchase the batteries fairly soon. I was considering a bunch of eight 5000mah 6s hobbyking/turnigy's running four groups of two in series then paralleling them giving 20ah and 880whr's. This at about $600 seems to be reasonable. I did stumble across the 22000mah 6s Tattu that would work out to be about the same. Also jonescg custom packs. Any thoughts kids?
Also is regen braking a suitable option as a rear brake instead of a disc rotor? If I could do away with a rear brake altogether that'd be nice. This wouldn't be so much to get a recharge but to negate having to build a disc set up in board of the drive sprocket, do able but a pain if can be avoided. The drive sprocket is mounted as far out as possible for swingarm clearance and countershaft sprocket alignment. May have to get Matt involved here.
Am out of the workshop this weekend unfortunately but next week is dedicated downhill time, so yes it will be welded up with ensuing pics, I promise.
Cheers
Ecobogan
100 W
So I happened by some batteries today on our dear old ebay. They're 5000mah 6s 20c Turnigy's that are advertised as being slightly 'puffy' due to mild overcharging.
Old mate assures me that they are still fine and are relatively new. Now at $60 for the pair, and there are three pairs, tells me that they're are proper knackered.
Can Li Po's be 'puffy' and still be ok? The price is right and they are nearby but this could be coz they're very wrong. Tell me what you think and here's the link
http://www.ebay.com.au/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.H0.X5000mah+6s+lipo&_nkw=5000mah+6s+lipo&_sacat=0&_from=R40
Old mate assures me that they are still fine and are relatively new. Now at $60 for the pair, and there are three pairs, tells me that they're are proper knackered.
Can Li Po's be 'puffy' and still be ok? The price is right and they are nearby but this could be coz they're very wrong. Tell me what you think and here's the link
http://www.ebay.com.au/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.H0.X5000mah+6s+lipo&_nkw=5000mah+6s+lipo&_sacat=0&_from=R40
Ecobogan
100 W
Ok so I found some direct material on the viability of de puffing these exact batteries. Thank you Aussie jester and endless sphere, or should I say endless fear. I might be able to get all 6 for about $100 if no one bids
Ecobogan
100 W
Missed out on the batteries, they went for nearly shelf price anyway. Well it looks like my new TIG that I scored is an equal piece of shite compared to the old one, very ratty arc pulses and will only run on max amperage etc and it was all pissing me off good and proper. Out of the blue my good mate Fez lent me his AC/DC square wave adjustable AC balance star trek machine to finish the job and instantly I was pulling some classy welds. Made all the difference, especially in out of position and awkward corners.I've got a wee bit more welding to do but it is 9/10 done. There'll be a fair deal of trimming and cleaning up to do
Attachments
Ecobogan
100 W
Bit hard to see what's going on in the photos. I'll try taking the next photos outdoors in better light. Will be in the workshop tomorrow
Ecobogan
100 W
Ok you're all right, my welds aren't super classy but about 50mm of one of them was uber nice. Finished off all the TIG work today and did a mock assembly. No flex anywhere and she's all still square and true. As mentioned there's a bit of trimming and cleaning up but getting close to fitting the astro 3220
Attachments
stuntmanmike
100 W
Sick!
Ecobogan
100 W
Anyone have a link to a detail of the best way to fix the drive gear to the astroflight shaft?
Was thinking a double d, key, press fit, spline or something similar.
The inside of the gear is 14mm and the shaft is 12.7 so needs some kind of coupling adapter.
Sick. Yes hoping so
Was thinking a double d, key, press fit, spline or something similar.
The inside of the gear is 14mm and the shaft is 12.7 so needs some kind of coupling adapter.
Sick. Yes hoping so
Drum
100 W
Hi Ecobogan, That's coming along really well. Relatively compact, no clearance issues and the weight is low and forward.
Looking forward to seeing it finished!
As far as fitting the gear to the 1/2" shaft of the Astro, Matt ("Recumpence" on ES forums) makes really well engineered drives using these motors. It might be worth looking at his builds for ideas.
If you can find an adapter bush with a "Double D" bore to suit the 1/2" shaft, it would be fairly easy to machine it to a snug fit in your gear and TIG it in, although the wall thickness would be minimal. I wonder if your gear is hardened in the bore.. if it could be bored out a bit to leave greater wall thickness in the adapter it would be easier.
These adapters are hard to machine by conventional machinery, but can be laser or waterjet cut to quite good tolerances, although they might have to be made up of two or more side by side because the cutting accuracy drops with thicker materials.
Dave
Looking forward to seeing it finished!
As far as fitting the gear to the 1/2" shaft of the Astro, Matt ("Recumpence" on ES forums) makes really well engineered drives using these motors. It might be worth looking at his builds for ideas.
If you can find an adapter bush with a "Double D" bore to suit the 1/2" shaft, it would be fairly easy to machine it to a snug fit in your gear and TIG it in, although the wall thickness would be minimal. I wonder if your gear is hardened in the bore.. if it could be bored out a bit to leave greater wall thickness in the adapter it would be easier.
These adapters are hard to machine by conventional machinery, but can be laser or waterjet cut to quite good tolerances, although they might have to be made up of two or more side by side because the cutting accuracy drops with thicker materials.
Dave
Samd
10 MW
Seriously cool project mate, well done.
Ecobogan
100 W
Cheers lads. I actually bought the motor and controller off Matt himself, should be here in a few days.
Have searched through a few of his threads and couldn't find much detail on the gear mount other than a picture of what's clearly a grub screw on flat arrangement, there may be more info I haven't discovered. I asked Matt about this when I bought the motor, may have to ask him again.
I thought it may need something more serious, perhaps not. This is next on the menu
Have searched through a few of his threads and couldn't find much detail on the gear mount other than a picture of what's clearly a grub screw on flat arrangement, there may be more info I haven't discovered. I asked Matt about this when I bought the motor, may have to ask him again.
I thought it may need something more serious, perhaps not. This is next on the menu
