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

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another concept with a gearless mini hub motor from conhis in china


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):



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


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:

[vintagerider]

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, [quote][/quote] 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

[vintagerider]

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 thanks

[LegendLength]

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).

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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.

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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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The Phaser Gearbox won't work long because it has a 13tooth (or less) sprocket on the crank arm. Even a very light person will make it fail when it engages

primary reduction to a jackshaft? what do you think?

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The 1KW for the NuVinci is WRONG!

It has 5KW max, look here: http://www.fallbrooktech.com/docs/kitform.pdf

[Nehmo]

Impressive. I'm following everything you do.

So, I've got a question for now. The freewheels, you used a Dicta freewheel already attached to the chainwheel (front sprocket). How do they attach to each other?
Your recommendation is UK£ 39.95 = $63.32 U.S. dollars before shipping form the UK. Naturally, since you're in Germany, your suppliers are in Europe. I'm in the US, and it usually isn't worth buying from European suppliers for me because of the shipping cost.

I'm wondering if buying the chainwheel & freewheel combined is the way to go. The alternative is getting them separately and attaching them to each other via a crank spider or something.

[LegendLength]

I did a quick search on the nuvinci max power and found http://www.motoredbikes.com/showthread.php?t=8227 :

[...] if you expect them to last,and it would seem prudent to limit the torque input to below 70,corresponding to about 1.7 HP.(at 130 input rpm)

So about 1.0 - 1.5 kW max power. But it must be talking about the n171 because that thread was from 2008.

I'd probably agree with you here and lean more towards the manufacturer's spec for max power (for the 360). There doesn't seem to be much real world testing out there unfortunately, even on the older 171 models.

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The most special thing with the freewheel crank is the SPIDER!!

It's just a special crank arm with BSA-threads on it.

Don't know if I would spend the $65 for this agian. Because most times I pedal anyway

If fallbrook says, the NUVinci can last 5KW, than it will I guess, just look at that link again I posted

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Has anyone ever seen a gearless friction drive planetary except the NuVinci? Opened up a so called "geared" sensorless hubmotor a Q126-SWX, reated at 36V, 210 rpm and 6.1amps
The ratio is about 1:10 I guess
I'd like to see how this performs at 72V
I ask myself if a KU123 100V caps can handle 72V??

[Spicerack]

I think this gearless hub motor will slip and not do very much at high power. They also have been known to crack the outer ring. If you want power, it has to be gears, not friction type.

[docnjoj]

Has anyone ever seen a gearless friction drive planetary except the NuVinci? Opened up a so called "geared" sensorless hubmotor a Q126-SWX, reated at 36V, 210 rpm and 6.1amps
The ratio is about 1:10 I guess
I'd like to see how this performs at 72V
I ask myself if a KU123 100V caps can handle 72V??

Hey Crossbreak!
Where can I get a motor like that? I don't think if it is like the Tongxin it will take 72 volts but they are quiet!
otherDoc

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I think this gearless hub motor will slip and not do very much at high power. They also have been known to crack the outer ring. If you want power, it has to be gears, not friction type.

Thanks for your post! Sorry, my post is OT because this motor is not meant to be build on the black bike this thread is about.

High power at low weight means high rpm, which means a lot of noise with gears. My 80100 concept is really noisy. Couldn't get it much more quiet by encapsulating it.

The gearless drive will slip if the max torque is reached. Just like the NuVinci. I tested it with 20amps at 36V, that was ok. So it should even last 20amps at 100V because the torque will stay the same. I guess the best efficency region of this inrunner motor is at 5amp at 2000rpm and about 42Volts input (just my 2 cents). It's a 15N4P inrunner with a about 50KV.

I wanna go for 55V with 15s lipo or 72V with 20s, but I want to stay below 15amps. I want to use a KU63. I guess 55V are all it can take. The FETS are HY-1707 rated for 70V. I will change the caps.

Its for my 1KWH long range stealth bike with middle motor. The motor mount will be in the lower frame triangle. I will post picture in new thread soon. It has a thirty year old 3-speed Sachs Torpedo Hub which has really little friction and is very durable to beat hills.

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Sadly I can't tell you where to get such a motor. The guy I bought it from is a polish guy who disappeared

[Edit: they are still available if you find a reseller]

[docnjoj]

Sadly I can't tell you where to get such a motor. The guy I bought it from is a polish guy who disappeared

Well Crossbreak, thanks anyway. There is a thread on a Tongxin motor as a mid-drive on someone's trike that looked quite professional. He used it attached to the front boom of the tadpole and ran it off a left side freewheel on the threaded portion of the case. It seems to be ideal since you have a split axle on those motors and there is really no weight as a midrive on it.
otherDoc

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Hey docnjoj !

Thanks for the TongXin MidDrive tip! It's just like I imagine, also thanks to y amberwolf who tried to build that:





amberwolf shows us a 24t sprocket on the motor

I think the sprocket is too large for my purpose

The motor does 190rpm at 36V. I want 100 at the crankwheel. I have 38t on it. So I calculate t=38/190*100=20

I guess I will be lucky with 18.

[docnjoj]

Yes I am definitely looking forward to following AW's build.
otherDoc

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Notice that one bearing is missing. I had only one 12x21x5mm one, I have to buy a second. It should be pushed into the right part in the picture below. Also a bushing which should be between the bearings isn't manufactured jet.



I know that a second freewheel doesnt make much sence, but the one I used has much less drag than the originial one still build-in.

[docnjoj]

That looks very professional and sanitary, Crossbreak. I will subscribe mainly to see how well that roller motor holds up!
otherDoc

[Samd]

+1 subscribed.

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OK! Now you got me

I will test this motor in my black mountainbike first, just like the Conhis motor
i mean this one (note my new 130mm fork and 203mm brake rotor )

The fork was 40 bucks from the bay, the disk about 10 with shipping from china

I can also recommend the upper head light ( an Cree XML T6 Flaslight front end ), for about 15 bucks with shipping from the chinese bay.