Student project: bike drive [Team1]

[[Team1] Gabriel]

Hi erverybody!

My Name's Gabriel and I'm a Student from an University of Applied Sciences in Vienna, study path Mechatronics/Robotics.

We have a subject called "Project- and Processmanagement".
Our task in this subject is to run a project where we create a product (in theory).
During this process our lector supports us with his knowledge and helps us when we have questions about the "processing", like
legal requirements, product costing...
An example: the group last year decided to build a roboter (only in CAD), which collects dog poop on the streets :-D
You can't imagine how many problems occurred an how many steps would have been necessary to comply with legal requirements of the Austrian law to really implement such a robot ^_^

Ok, so why do I write such an uninterresting crap into an eBike-forum?

Originally I wanted to build a mountable drive for a bicycle, so I simply made the suggestion that we build a drive which fits on most bicycles... There were many cool ideas, like using the metro at night for heavy haulage transportation, but they chose mine, hooray!

So we now have about one month time to complete the project. There are two Teams of 6 people each, which are considering it like a competition. Still, I hope [Team2] decides to join us in this great forum with a parallel thread.

Even if we don't build the drive for the project itshelf, I'm still going to build one!
Maybe till end of 2010.

-------
Here we will post our Ideas, CAD-drawings, product costings, marketing ideas... et cetera.

This idea of a "siply to use"-drive may not be new to you or anything special - but everybody who wants can help us developing a good and easy to use drive, we would rejoice over any help you can offer us.
-------

(We will try to read through other posts so that we learn whats realistic and what's nonsense... but we're all new to e-bikes or
creating drive setups, so please don't be bugged if we ask stupid questions or post nonsense...
So it would be nice if you could point out when we are wrong, or when something might not work as we expect ist to... thank you

So... lets do it!!!

 

[[Team1] Gabriel]

In the first meeting we were not sure about what the drive should be used for, what the main direction should be we want to develop the drive into. For fun-driving? Tours? "Easy and quicker to work"-driving...?

So I thought long about why I even wanted to build an eBike in the first place, and what the originally goal, the main thought behind
the drive was...
My main idea which it was based on, was to create a eBike setup, which is cheap, easy to install an easy to use - so that the
bicycle itshelf would become more attractive as an alternative to cars for hurdling short to mid range distances.
-> So that people use less often their cars and maybe, just maybe completely switch to alternative propulsion systems for
automobiles.
Thats the main point - at least for me.

Maybe my colleagues want some other orientation, which we will also discuss here (I hope).

 

[dogman dan]

Suggest you search keword Keppler for some good ideas. Also look at the non hub motor section.

Otherwise you'd be sortof stuck with just buying a kit hubmotor and bolting it on.

The battery is the hardest part, but ready made lifepo4 solutions are out there.

 

[[Team1] Gabriel]

Thanks for the hint!

Otherwise you'd be sortof stuck with just buying a kit hubmotor and bolting it on.

Yeah, I hope we can avoid that and find a solution which is a little more sophisticated/enterprising than that. ^^

I asked my colleagues to think about a concept and to post their ideas/sketches here bevore tomorrow (hope the do so, lol).
I will post my concept ideas shortly.

I would also appreciate if some interrested users could comment on our ideas an evaluate their usability and realizability (or even better, bing in their own ideas).

 

[torker]

Welcome to the forum Gabriel. For the most simple drive I would look at Keplers friction drive. It would still be homebuilt as opposed to a hubmotor. Otherwise a Curry type with a chain to a sprocket on the rear wheel. Good luck. Use the search a lot

Oh I just thought of another possibility. A push trailer. Then you can use it on almost any bike..

 

[[Team1] Gabriel]

Wow, that looks really like something!
here for example: http://endless-sphere.com/forums/viewtopic.php?f=31&t=20491&p=298028&hilit=kepler#p298028

Ivan, I think you were the one who had the idea in our meeting to use a friction drive...
I think you don't need to post a draft or anything any more
But you could search and think about the pros and cons and post them here... or the person who had the idea.

...Curry... sounds yummy ^_^ Will search for it.

A push trailer would really fit on almost any bike but...... we all agreed totally as one of us said:
"I wouldnt want such an ugly looking and unhandy drive hanging at the end of my bike"

 

[torker]

Haha yea but search out " Woody goes shopping" It is a push trailer that holds a lot of groceries.. Kepler is a guy on here that makes an outstanding friction drive.. And Curry - not the spice- sorry.. made rear chain drive bicycles for years. I think they actually switched to hubmotors this year. I could be wrong :|

 

[adrian_sm]

Gabriel"]Thanks, now im really curious what this Kepler-stuff is . Will search for it.

To save you some searching here are links to a couple of "bolt on any bike" style friction drives.

First up the "kepler" drive.
http://www.eboo.st/
http://www.endless-sphere.com/forums/viewtopic.php?f=31&t=20491
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=16550

Second up, the Hidden Power.
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=21357

Finally, another bunch of students came up with this. Not a bolt on kit, but still a nice complete looking product.
http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=21159

Looking forward to seeing what you come up with.

- Adrian

 

[[Team1] Gabriel]

Nice! Thanks Adrian.

Man, the "hidden power" looks awesome! So small!

 

[docnjoj]

Here is a very simple yet strong idea! Made from hardware store stuff.
otherDoc

http://endless-sphere.com/forums/viewtopic.php?f=28&t=14387&start=0&hilit=pillow+bearing

 

[michaelplogue]

Goped had an interesting 'all in one' unit that included everything in one package. Dosen't look like they are selling it anymore. It's no longer listed on their web site.

 

[[Team1] Gabriel]

Yeah! Also a good idea.

And this Goped...that looks really easy to use and install - I hope we can come up with a similar good idea!

I see now... it wasnt a mistake to go to this forum

So here my originally idea, which I wanted to build before I knew about the project.
I didn't find anything with "curry" maybe you would call this a Currie-drive?

I wanted to use a relatively cheap BL Motor from Hobby King (I am actually buying there, but for RC-flying it should have used max. around 200W, that would have been enough.
Like you can see in this draft I made...:

... I wanted to use drivebelts (red) to lower the noise level. I also planed a "free wheel" on the big belt gear below the controller, so that one could pedal without rotating the motor.

Funny, my draft actually fits one of my 1kW RC-setups nicely:

OT: here you can see the setup in action, topspeed 190km/h, start around 0:44.

I think when I would want to use max. 200W, I could build in an even tinyer Motor.
I think the "box" with all components would easily be designable below 1kg.
+ ~4-5kg LiPo battery I had in mind would have made a nice setup for <40km distances (with pedaling).

Pro's:
+ relatively easy to install (mounting maybe with cheap hose clamps from a hardware store)
+ light drive (<ikg)
+ motor + controller in one box - saves some extra wiring

Cons:
- Dangerous, exposed chains & pedals turn when Motor works - like when you use throttle control, not a pedellec setup..
- still 2 things to install - battery pack and box
- not inconspicious/elegant
- could get out of place after bike falling down/ smashing ground
- need to expose chain, you would have to remove the chain case (if you had one)
- you can't use all gears any more


That was my originally Idea, second's coming...

 

[amberwolf]

What you show there, driving the bottom bracket chainrings, is a "cyclone" or "stokemonkey" type of drive, also known as a BB (bottom bracket) or mid-drive.

They can work very well, in a wide range of conditions, but they are not as easy to adapt to every bike as some others can be, because of the wide range of spacing of chainrings, cranks, frame tube sizes, angles, etc.

Also, they require changing the original cranks for freewheeling ones, unless you always pedal along with the motor. One disadvantage of always pedalling along is that if you gun the motor throttle you can accidentally knock your feet off, and get your heels clobbered for a bit while you try to recover. My CrazyBike2 (in my avatar) uses a drive a little like that, and didn't freewheel the cranks, though it will once I get it back working again.


Another option that I have pondered but have not yet seen done (though ti probably has been) is to drive the bottom of the chainline coming out of the cranks, so that it pulls the chain along.
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=21690&start=0
I just started the thread now, so I can work out the idea there without interfering with your thread, but you can take any ideas you want from there and run with them.

 

[[Team1] Gabriel]

Thanks for the explaination... many names for just one drive, easy for a beginner to onfuse something.

but you can take any ideas you want from there and run with them.

Yeah! That's the spirit! If all people had that altruistic attitude, the world would be a much better place 8)
Nice, it seems that at least here are a bit more of this kind souls concentrated



Ok, back to topic.
My second idea came after I stumbled across RevoPower:

That a gas-operated drive is out of the question is absolutely clear,
but the idea itshelf - to just change one wheel - and only the wheel, sounds similar universally usable as a friction drive to me.

So why not pack everything into the front wheel? (For that question it would be nice if some of you, more experienced guys, could comment on)
(but of course the controller/batteries would not rotate with the wheel!)

Sure, you would not get much range - (how much? Let's say we use A123's. Another question where some experienced users could be of much help, because you can easily and quickly estimate what we would have to calculate! I mean, we have to calculate it later anyway, but you know, just that we have some data we can discuss on)
- but range is not the main issue here, (as long it concerns me, I'm still waiting for some input from my folks).
This would also mean less batteries, which are still the most expensive part - so it gets cheaper (yeah, an advantage! ), but is still an usable drive for short to mid range rides.

You just wold need to fix the batteries, controller and motor to some plate, (hub or geared RC-Motor - choosing what would be cheaper), fix the plate to the shaft, the shaft to the fork (similar like in the picture, but easily removable), then attach the turning output in some way (clutch? fixed?) to the ball bearing mounted spokes and voilá.
And when you want to charge the batteries, you simply open the quick release, take the wheel with you and charge it in max. 45min.

Pro's:
+ very easy to install
+ cheap
+ (conditionally) light in weight
+ relatively cheap charger suffices ->
+ small battery means also possible fast-charging times with a cheap charger
+ nearly no cables... no... hey!! Maybe really NO cables -> what about a wireless throttle control! - yeah! ^_^
+ can be designed very attractive (see picture above)
+ no annoying battery packs which occupy space
+ no screws/Tools needed to assemble
+ disassembled in a few seconds

Cons:
- short range
- no inbuilt charger possible/reasonable
- security? (Or just take the wheel with you into your home, office... shopping cart :lol: )
Can't think of more cons at the moment, sorry

Sounds like much work concerning structure and design, but hey, why are we here?!...

Leaves behind the question if this is viable...

 

[[Team1] Gabriel]

Hey, if we would design that concept in a certain way: plates instead of spokes, with different size holes punched into... and painted yellow...
...it coincidentally would also fit the name I initially came up with: Cheasy - (cheap and easy) :lol:

 

[adrian_sm]

That sounds just like MIT's Copenhagen wheel.

http://senseable.mit.edu/copenhagenwheel/

 

[[Team1] Gabriel]

Hmm, at first glance the concepts look a lot alike.
But when you take a closer look you see that this is just a style-product. Not soo expensive for such a kind of product indeed (600$), but i'm not so sure about the usability of the batteries - and all the rest.
Somehow this wheel insn't very atractive to me ... not because of the form or anything, but the teaser is just... no information about anything, also on the whole site: only style, style, style.

And this issue about "environmental sensing capabilities"... may be nice, but I mean even if you know how much CO and NOx you breathe and db you get into your ears, you can't do anything about it at the moment, and I'm pretty sure nobody would turn around and take a total detour only because some values on their phone changed.
What's nice is the idea to save the data of your trip on your smartphone (an iPone of course) , but not really necessary.
You could buy a cheap wireless speedometer and would have saved much development costs that way.
And you haven't even a tangible throttle control (ok, as a pedellec, changing motor support level through your phone is passable)... but changing gears through your SmartPhone?!?!
(When they would at least change automatically, but this... I better leave no comment there)

The other drive would have at least one big advantage: easy to take with you and charge. (Where do you charge your copenhagen-bike when you live in an 14th floor apartment ?)
And: with this concept you could keep your gear shift :lol:

Thanks for this information! - now I know that this isnt such a bad concept and also realizable, because they wouldn't have built it, if it would be too uneconomical or not worth building.

But still - please give inputs what you think about the viability, batteries, possible range(let's say a max. 200W Motor), or maybe you even have suggestions for the mechanical implementation...?
Or do you remember an old thread where such a concept had been discussed?

Thanks :wink:

 

[[Team1] Gabriel]

Now I suddenly realized one huge disadvantage of the coppenhagen wheel: what if you forgot/lost your smartphone?

 

[bandaro]

Gabriel"]
So here my originally idea, which I wanted to build before I knew about the project.
I didn't find anything with "curry" maybe you would call this a Currie-drive?

I wanted to use a relatively cheap BL Motor from Hobby King (I am actually buying there, but for RC-flying it should have used max. around 200W, that would have been enough.
Like you can see in this draft I made...:

... I wanted to use drivebelts (red) to lower the noise level. I also planed a "free wheel" on the big belt gear below the controller, so that one could pedal without rotating the motor.

Funny, my draft actually fits one of my 1kW RC-setups nicely:

OT: here you can see the setup in action, topspeed 190km/h, start around 0:44.

good to see schools doing projects like this, i hope to do one later in my degree (industrial design). now, i am currently working on a two stage reduction crank driven system like you had posted, and i dont think that it will suit your criteria to be honest.

this is because a) it really is designed around a bike/specific style. the system you have drawn for example would work on that bike, but if the frame is a slightly different shape, or even the tubes are different shapes then it is not going to be a bolt on kit. my system is designed entirerly around my bike, pretty much all the systems similar are designed around the builders bike...

b) the gears you have drawn, assuming they stay to scale, will not be very strong, they should handle 200w or so, but even steel gears that size would be a limiting factor. i looked into beveled gears like you have for my build but they were simply to expensive for me at the width i would need, so i am using a pulley, not ideal for the second reduction but i shall deal with that when i can.... as said freewheel cranks would basically be a must.

i may get shot for saying it, but either a hub motor or a friction drive i think are the best bet. hub motor kit that includes a rear wheel with the motor, wires, a battery to hang from the top bar on the triangle and a throttle would be the simplest for a hub motor kit. battery could be smaller and fit in one of the seat bags, depending how much range you need.

for a friction, something like keplers design, the expendable length will fit any wheel size, all seat posts are round, and it does not effect pedaling/rolling. battery mounting will again depend on the range you need, but could be anywhere really. a wireless throttle wouldn't be too expensive and could greatly help with simple installation.

good luck!

 

[[Team1] Gabriel]

Hi
Thanks for your reply!

I believe you just quickly scanned over the text and looked mainly at the pictures, so maybe you misunderstood the drawings slightly, but I could be wrong:

.... but even steel gears that size would be a limiting factor. i looked into beveled gears like you have for...

For the gears in the box I planned tooth belt driven ones, so that you have less wear; and primary it reduces the noise level.

as said freewheel cranks would basically be a must.... but if the frame is a slightly different shape, or even the tubes are different shapes then it is not going to be a bolt on kit...

Yeah, I think that are the two main problems of this design.
But I wanted to post my first idea anyway, even if I knew that this solution was not very universal.

i may get shot for saying it, but either a hub motor...

Kabaang!

I think a hub motor set is out of the question, because everything you have to handle with the chain or in the back wheel area - people say: "ah, that's to complicated for me to install, I think I'll stay with my old bike", or they just are too lazy to do 45 minutes of work on their bicycle (i think that unexperienced people would al least need that much time to install everything, when they got a hub motor set).

Also it would be very unadventurous if a bunch of students like us just compilated a few finished parts - and didn't even clamp them together in reality (because this is a theoretical project) - when we could do so much more.

But dont worry about the theoretical part... like I said, independent from the outcome of the project, I'm still going to build the drive this or next year, that's a given!

 

[[Team1] Gabriel]

Here is one possible way like I ment it:

the grey parts are fixed on a plate (I didn't drew the plate, you have to imagine it is there; and all parts are glued onto it or something like that) ant the plate is fixed with the shaft.

the red parts can spin.

 

[bandaro]

yeah, the wheels are a great big place where plenty of batteries can be mounted, just two problems:

1) so much mass on the wheels will make low range speeds very inefficient. torque will be low as well.

2) gyroscope. trying to turn with that much weight on the front will be more difficult as it is, but when you have some speed the wheel will try to stay vertical, there are some wheels for kids bikes that have a weighted wheel that can spin inside the regular wheel frame, to help kids stay upright when riding slowly. cant say how much of a gyroscopic effect you will have, but i imaging it will be noticeable, making turning at speed much harder.

the trainer wheels: http://www.thegyrobike.com/ they may have a german speaking site also... sorry to tear apart the idea, it would be really simple to install otherwise. have you looked at the petrol bike motors? they may have some drive ideas you could copy.

 

[amberwolf]

Also take a look at the http://neodymics.com site; there is a document there with a battery / motor wheel too.

 

[Miles]

This one got less publicity than the Copenhagen wheel:
http://green.autoblog.com/2009/02/19/mit-greenwheel-simply-an-electric-bicycle-revolution/
http://techtv.mit.edu/videos/2385-green-wheel---smart-mobility-ubiquitous-computing

 

[liveforphysics]

Supremely poor motor and ESC choices for an EV appliction.

Each reduction stage is a new point for failure, efficiency loss, noise (even with belts), needless complexity, etc.

A motor that handles 1kw just fine when it has 100mph propwash blasting over it, and it's almost always in it's optimal RPM range is a lot different than being enclosed in a wheel and having RPMs directly related to vehicle speed.

I'm not any fan of the bionix system, but in this case, it would seem if you're determined to fit an entire drive system into a wheel for some reason, simply mounting as many LiPo packs as possible around the outside of a bionix hub would give a silent, more reliable, cheaper to build, more functional end result. (yes I know in the bionix example the controller is fixed to the stator, so it wouldn't be quite that easy, but the idea is the same.)