another 80-100 rear drive build thread (now with Tongxin)

crossbreak

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Hey guys!

Since my original Thread http://endless-sphere.com/forums/viewtopic.php?f=30&t=30387&start=30

got too much OT, this is the continue of my build. Today I will start making the frame clamps of the gearbox. But first some pics of the bike ( a 2003 Giant XTC Mammoth):

(I bought it for about 400 bucks from the bay, it was only that cheap because the fork leaks and the front brake was missing)

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This is the latest version of the drive:
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Thanks for following this, I learned a lot from the other members, that's why I wanna share my ideas But new ones are always welcome, please comment!
 
Interesting build. Where did you get those hand guards from?
 
And your search term on the bay would be? Sorry I don't mean to side track your thread, but would love some of these.
 
motocross hand gards:
http://www.ebay.com/sch/i.html?_nkw=motocross+hand+guards+&_cqr=true&_nkwusc=motocross+hand+gards&_rdc=1

http://www.rockymountainatvmc.com/typeDetail.do?navTitle=Control&webCatId=12&webTypeId=191&navType=type
 
frame mounts:
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I used 10mm alu sheet, but I should have used 12mm. The screws arre all M6

The mounts can also be used as hub motor mounts. The width should then be 100mm, not 80mm.
pieces of bike tube portect the frame from scratches.
 
Hmm quick question - Obviously there is a free wheel in the rear hub to stop the pedals from spinning when you're not peddling (or the motor is not running) while the wheel is spinning - no different from any normal pushy out there.

HOWEVER! What's stopping your feet from being ripped off when the motor is running? What stops the peddling going nuts when you get the motor going? I'm assuming another freewheel setup between the peddles and the motor?

Sorry I know that's nub. Just curious!
 
I'm assuming another freewheel setup between the peddles and the motor?

that's right. A DICTA freewheel between rigt crankarm and the chainwheel prevents the cranks from turning while using the motor. I got it from eclipse bikes.http://www.eclipsebikes.com/chainwheel-cranks-p-998.html The other standart chainrings (44T and 32 T) are just bolted with the standart four srews on it. Yet I don't have a front derailleur, maybe I won't need it anymore when getting support from the motor. I can still shift the front chainring using my right foot :D

Another one on the secondary drive shaft (the one with the small sprocket and the big plastic gear) prevents the motor from turning while pedaling. It's visible on this picture (the sprocket on which the big plastic gear is mounted):


In total there are three freewheels build in when it's done.

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crossbreak said:
Hey ...............
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............

inspiring drive/build mate, ive been debating how to go about a mid drive for a while, and this might be the thing that pulls me away form a middriving hub to a 80100/8085... Re-terminating seems like a good option since it almost halves the kv, and would be an interesting project in itself to...

What material is your 1st reduction drive cogs made out of? is that nylon/strengthened? and how much power do you intend running? I could only see reference to 45V, but not to amps...

edit
forgot to ask too, are you using a CC or a ebike (ie lyen) controller?
 
Hi sn0wchyld,

I didn't care much about the electrics yet. I designed the gearbox to last about 10NM at 4000rpm at the motor, thats about 4kW in short term, with steady load it should last about 3NM at the same speed, about 1.4kW. I hope that all of the chains and gears will last about 10.000 km or two years with good lubrication (including the final shift drive). Then they will be replaced all together.

The bike should not be faster than 35mph or 55km/h, to save battery capacity. Wind drag makes the most, which rises exponentially with speed.
The pinion gear is made of 11SMnPb30 Steel (not stainless), big one of casted polyoxymethylene (POM), their module is 2.

I will start with a sensorless 12-FET, 37V, 15amps (about 500W) with 10ah 10s2p LiPo. If that runs good, I want to increase it to 24-FET 48V, 100amps, 13S Lipo with 20ah and the same but then modded controller. I want to stay below 60V because of legal issues. I also don't like to add halls or optical sensors to the motor, but most likely I will have to.
 
another concept with a gearless mini hub motor from conhis in china
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the motor was simply added to the elongated drivechain. It pulls really hard whit a 16t sprocket (the 2mm alluminium bar to the front takes this load). The freewheel was just screwed on bsa-threads on the motor, but reversed. That way it drops out when the motor engages.
To prevent this, I screwed a plate at the end with three M3 screws, which worked really fine for normal riding. But when I rised the maxamps to 30, the screwes cracked during a hard bench test :( (full throttle, while spinning, full brake):

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The coulor of my jeans has nothin to do with my political bias :D


Six will make the job I guess.

Sadly the enlacement angle of the pedal chainwheel is to small, thats why it slips when pedaling hard :( guess a enduro chainguide would solve this. The chain survives longest keeping 180 degrees at least.

It was nice to see how it performed, but it's sluggish at 36V compared to the 80-100. This one needs more voltage. But at more than 48V a 16t sprocket is too big, it would need another reduction stage. Otherwise its quiet and waterproof. The shaft is too long to simply put it in front of the bottom bracket, it would interfere with the crank arms. The shaft could be shortened if I could get it out. Has anyone ever disassembled a gearless motor? Can't see how this works, removing all of the screws doesn't help... what do I oversee :?:


[EDIT] I know now how to open up the motor. You need a puller. Watch a video about this, search for "hub motor dissasemble" [/EDIT]


BUT this motor is really load at low speeds and high torque. Thats why I sold it in the end.
 
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Another concept with the 80-100. It is calculated for 4KW @ 4000rpm peak and 2.5KW@ 3000rpm continous.
The chain drive won't survive this very long. That's what I'm researching about concepts with build in gearbox. ATM im thinking of an SRAM S7-Speed hub box build into the output axle of the final drive. This would reduce the tourque it has to handle by factor 2.5. CAD-Pics on that topic will follow soon.

Another idea would be to integrate the shift chain into the gearbox like this phaser gearbox:

phaser400_4.jpg
 
wow very cool build i was considering a hubie but i am now leaning towards this design, thank you by the way as i searched everywhere for that free-wheel crank, bikes.http://www.eclipsebikes.com/chainwheel-cranks-p-998.htm. i love this forum people have some great ideas here. the plastic gears are for quietness i presume? i find a lot of links to cool stuff on there threads :D
 
just a question? do you think a nuvinci hub would work on the back wheel? with that kind of power would it destroy the hub? just a question not meaning to suggest, just something i was wondering about since nuvinci does warrantee there hubs with low power e-bikes, (not sure the power at the moment) oh one more thing what is the reduction in your gearbox idea before crankwheel :D thanks
 
I've heard the nuvinci cannot handle more than 1 kW or so, but may be mistaken.

Great looking build btw. I like the lack of a belt between the motor and the jackshaft. Do you know how strong the plastic gear is though? (just about to read your original build thread so ignore if it's already answered there).
 
The 1KW for the nuvinci can be reread at their specs. But the 1KW is at 1000rpm. It should mean that it can last about 10Nm torque.

The Plastic Gear has 60 teeth, module M2 and can last 18Nm torque, the motor sprocket has 12T, that would be 18NM/60x12=3,6Nm at the motor. That is about 2.2KW continous power it will withstand.

If you want to go further you should just take a larger motor gear. but you have to keep in mind that you should get an over all ratio from the motor to the pedal cranks of about 6000/120=50 if you go for 48V and take the 130KV 80-100.
 
I think for a high power concept one should go for a 48V gearless hubmotor build into the frame triangle with a 1:2.5 ratio chain to the rear wheel. Then the battery voltage should be raised to 200V. The maxamps to about 70.

That would make about 200Vx70=14KW

My concept aims more on efficency than on power tahs why I calculate with 2.2KW continous, since I wont consume more than that in real life use. Otherwise my battery would be empty in less than half an hour :( (with 37V Lipo 10S 20Ah, 0.72kWh)
 
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