Magnetic gears, for a bicycle. Chainless bike, dragless drivetrain

[Cloxxki]

I don't believe the magnetic gears offer overunity. But that's not what my post is about.

All my life, I've been fed up with bicycle chain. They wear, get dirty, noisy, and break when least convenient. Oh, and they offer unwanted drag. Still, they are better than the alternative, V belts. Unless...
In progressive high-end bicycle design, the chain and chainline create more and more problems. I want to rid the world of those.

Enter, the chainless bicycle. And no, als not an cardan axle.

Imagine a bike tire or rim lined with evenly spaced directionally magnets. Say, one, two or three per spoke hole. I presume more narrow magnets will weight less and offer better traction.
Because, although magnet gears to my knowledge run 100% efficiently especially at bicycle rpm ranges, they do of course slip. Having the interaction at the very outer end of a bike may offer a distinct advantage over a typical bicle chain (cog roughly 1/10 the tire's diameter) should help. However at this stage I am not sure how it works out then the driven wheel is 73cm across, and the drive wheel is, say, 15cm. the drive wheel would need laterally place magnets perhaps, to account for side-to-side wheel flex (it a reality of life, and in fact aids rideability of the bike). The wide drive magnets might be curved around the receiving wheel magnets to add interaction? My agnetic knowledge already runs out here. Also, I can see a second or third drivewheel be added on the bike frame to increase slip-thorugh torque.

But imagine it for a second.
The rear wheel would be the same as the front wheel, except for the magnets on the outer diameter.  If you go crazy, some pedal power could be tapped off with a pickup coil and be transferred to the front wheel, either via more magnetic gears, or a hub motor. I am not proposing a full-on electric motor conversion becaue I suspect greater loss of efficiency that a regular bike chain. For a front wheel, even a cardan sytem is a real pain though. And channeling only ~20% of available power to the front would result in great handling improvement, for a limited amount of losses. It could even be programmed to kick in only above given power and torque figures, as those would imply an especially steep hill or deep sand/snow section. 60r/40f or 70r/30f power spread would be perfect there I suspect.

I need you to brainstorm with me, and hope to gain knowledge on how wel magnet gears perform. What kind of air gaps can they deal with, and what torque to expect? I would prefer to not have to laterally overlay between wheel and drive, as that's one of the limitations of a chain I was looking to overcome in the first place.

Converting the tire could be as easy as sewing a cloth strip lined with magnets in place behind the tread. In case of a rim, it could be easier still, and not mess with the tire (disposable item). Or a special magnet tube, even easier...

When more than one gear ratio is needed, this could all happen near the crankset. Plenty of technology exists that could be converted for that purpose, even variomatics.
The drive system would need a freewheel in there somewhere for most of us.

Imagine, a bike with no chain to lube, and smoother power transmission from pedal to tire...

Your thoughts on this crazy idea, please!

thanks,

J

[Cherryman]

Hi Cloxxki,

Intresting concept.

I played around with a bike gear/flywheel and cvt a while back (Just as a design study)

Here was my simplest version of magnetic driving, no gears.
(ignore the stuff on the back it is part of the flywheel construction)

But on the subject, the torque will be the main obstacle I guess.
It would be intresting to see if "skipping" when there is too much torque, make some kind of gearing.

Ideal would be a small magnetic CVT with a flywheel. 

Edit: Wrong picture, that one send us backwards. ;-)

Anyway, after this design study I came to the conclusion that having a good , simple CVT gear drive system could be very usefull to all kind of energy related issues.  I abandoned the bike, and still funneling around with an easy CVT design.

[Cherryman]

Here is a nice vid to help see possibilities:

http://www.youtube.com/watch?v=7ZpTIpLJxQo

[Cloxxki]

Thanks for your response! Great minds from great countries think alike...


As Dutchmen we find places to stick a CVT on a daily basis, don't we?


All,
Does anyone know about electro-enhanced magnetic gears? Does it exist, is it viable?
I am think of this to get a much greater peak torque performance from a setup.
For instance, if peak torque would be surpassed for 5% over a whole ride, a battery might be on stand-by to kick in the anti-slip torque support just in time before magnetic traction is lost. Not to aid propulsion, just to prevent the chain "from" temporarily becoming very elastic. If this would be possible, it would help the application of magnetic gears to bicycles greatly.
Thanks in advance for your insight here.

[Cloxxki]

Beauty...
http://www.youtube.com/watch?v=EAELukfr2oY