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

[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

[crossbreak]

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.

[crossbreak]

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

[crossbreak]

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

[crossbreak]

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.

[crossbreak]

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.

[GITech]

Awesome crossbreak! Thanks for the insite on many different topics and all the pics.

I just read both of your threads. You have done a lot of different things in a short time! Very cool!

I was just looking into breaks. I see that a 9" disc rotor is available for the Fox-40 (the fork I'm using), I was thinking about going for that but are much more expesive than ~$10. from china for a 203mm!

Oh, gotta cut it short, baby's crying!

Later,
Jay

[crossbreak]

[crossbreak]

I was just looking into breaks. I see that a 9" disc rotor is available for the Fox-40 (the fork I'm using), I was thinking about going for that but are much more expesive than ~$10. from china for a 203mm!

the 10 bucks was an auction. But there are tektro brake disks for 15 bucks fixed price. 9" would be more than 203mm.
But advertance for your bayb is most important. Don't bother with disk brakes My drive would be further if I'd have done that. Maybe I'd even had a child myself I see that you postet just minutes ago.. are you from europe?

You have done a lot of different things in a short time! Very cool!

that's what a learning engineer does I dont want to do sth. else the next 5 years. My concepts get cheaper lighter and more simple with each iteration (about 35 yet).

But I will come back to the first topic (80-85 hub) again.

Im really intersted in your topic. Please post more pics also

[crossbreak]

Finished the tongxin motor today (bushings etc.) , next sundays comes the housing. Sry for no pics.

I also started a tutorial thread about the delta to star resoldering for getting 75KV out of the 80-100 KV130, which I hope will be finished next sunday also:

http://endless-sphere.com/forums/viewtopic.php?f=30&t=36767

[crossbreak]

I threw away my primary concept. Not really stealthy. The new one is more
I exchanged the 18T 1/2"x1/8" frewheel sprocket for a 15T 8mmx3mm sprocket. That way the motor can be mounted below thebottom bracket.

Sadly I couldn't write the WYE tutorial, since I had too much to do. But here's the finished Tongxin motor, sadly I had no time for a mount yet
You can hope for next weekend

Notice the slots i sawed in to make it possible to push the motor into the extruded 90mm (100mm outer dia) alu alloy tube. The motor measures 91.05mm in diameter (edit: the upper cast piece is only 90.5mm). It was too hard to push it with the bench wise without the slots. I can pull it out again with a puller.




Notice the rather short chain
The sprocket has 15, the chainwheel 35 teeth.
Iknow that this is really thight, but it saves so much place. Let's see how long it will survive

[crossbreak]

the green mount is made from polyethylen, which was first rasped and heated to 130°C (it gets flexible at 100°C, it melts at 150??) in the oven then squeezed by the srews. Makes a perfect fit.

[crossbreak]

btw I had a short ride on it this morning. except the sporadic chain noises it is really quiet : sounds like bad allignment.

I'll try to make a vid if they're gone..

[crossbreak]

The mounts bend too much, thats why the chain makes noises and sporadicly jumped off. I fixed this problem by adding 2x20mm aluminium bars between the housing and the bracket to keep the distance when the motor pulls on the chain. It's a kind of a chain tensioner, it's not final, but it now works completely silent, the noise from the wheels is louder No cyclist or pedestrian I pass recognizes me first if I don't bell


another bar on the tension side of the chain:



The last problem to solve is the load on the front freewheel. It sometimes stalls, it''s bended to hard. the distance between it and the chain ring is too large (I marked it in the picture below). Another bearing between the shaft and the chainring could take this load (it's also shown in the cad picture below)

[crossbreak]

A Vid to show how silent it operates:

http://www.youtube.com/watch?v=5ErFn8hIpNM&feature=youtu.be

[crossbreak]

here you can see the bearing between the chainring and the bottom bracket that i meant.
The 8mm chain was waste after about 90km I'll try a 3/8 x 7/32" chain with 13 to 32T now.


the swing arm isn't where it should, but it shows the principle.

[crossbreak]

The chain cracked again due undercharged chain tension. A roller type chain tensioner cannot work good with a short chain.
Also, fastening the motor with it's housing on any frame part radially will always lead to bad alignment. So I decided to directly mount it on the bottom bracket by a 5mm alloy sheet on each side of the bracket. The right sheet will be fastened by the bracket directly, the left sheet by three bushings and screws on the right sheet.
The motor will the be fastened on the right sheet axially by twelve M3 screws. The left side will just have a hole in which the motor fits in.

I decided to use a spiral type chain tensioner now, which varys the distance between bottom bracket and motor axle. I've got one on my motorcycle which works great. Should look like these:

Edit: they are also called " snail cams", as denise told me.



I also shortened the Tongxin by one centimeter:



As you can see all the holes, I tried hard to radially fasten the tongxin with M4 screws and get the chain aligned. It worked so bad I cannot recommend at all. I thought, there are so many on endless-sphere who did it similar, it just has to work. It does but not very long, since it's not stiff enough. The green plastic spacer I made, sucks. It was just a bad idea. When I got the new sheets done ( I ran out of alu alloy ) , I will post the plans for everyone whos interested.

[shock]

Awesome work! Enjoyed reading this thread, very clean and well thought out designs. Personally I think this was the best design. Keeps the motor protected, has the reduction gears, and is still quite stealthy. Keep it up!

[crossbreak]

-

[crossbreak]

Awesome work! Enjoyed reading this thread, very clean and well thought out designs. Personally I think this was the best design. Keeps the motor protected, has the reduction gears, and is still quite stealthy. Keep it up!

[/quote]

thanks for your post!You are right, this design has many advantages as you mentioned. It is signal gear, but a three speed gear hub in the jackshaft would make it complete (it would take less load there). I'm working on this.

My Tongxin design has it's own 5mm alloy housing armor That's why it wont be harmed through dirt.

[crossbreak]

the motor could be mounted under the bottom bracket, the hubgear above. Inside the frame. I imagine a two sheet design like the tripendo (http://www.tripendo.com/) with blended edges. Wouldn't that be a beauty without an cables boxes mounted to the frame etc...

Such a frame souldn't be to hard to make if one has a good master plate like a great existing conventional frame