Originally Posted by Ecky (Post 672715)

Interesting in principal. However due to gears being different sizes, they would only align while rotating such that they're repelling part of the time, and would attract an equal portion of the time. I think this would only work with a 1:1 gear - which is 4th gear in most manuals these days. And, the reduction in physical contact would only be as strong as the magnetic force, which is to say, probably millinewtons or less, compared with hundreds of newtons exerted by the engine that needs to transfer between the two gears, forcing them together.

There probably IS friction reduction to be found in manual gearboxes that simply isn't happening because nobody is building new manual gearboxes anymore. It's probably also not the lowest hanging fruit yet.

Originally Posted by Logic (Post 672712)

This is just a crazy idea I had and thought I'd put 'out there':

Take your well run in manual gearbox apart.
Wrap thick copper wire around each gear and discharge a large capacitor through the wire to magnetize the gears so the tops are north and and the bottoms south. (not left north and right south. Although that may work too)

Now all the gears are magnetized such that they repel each other when the box is put back together.

Due to the very small gaps between gear teeth the repulsive force should be substantial enough to avoid gear tooth contact a lot of the time, and greatly decrease the pressure with which the teeth push on each other all the time.

I have no idea how much difference this would make?? Research Reqd!

You'd still have to add oil. (drag. maybe thinner oil?)
Then there's the issue of all that fine metal that usually accumulates on the sump plug magnet! On a well run in gearbox..?

It'd be great if some one here knows the maths in this and can chip in so I don't have to go look it all up! :)

Originally Posted by Ecky (Post 672731)

I've actually never considered magnetizing only small sections of a continuous steel object before. I'm not even certain you can, or how the field would propagate (would it cancel itself out?) and I'm not having any luck searching for an answer.

My best guess is that it isn't possible. I imagine the fields would cancel.

EDIT: It appears to be possible. It would likely be a very weak magnet depending on how the poles interact, and would be prohibitively expensive to manufacture. It's a fun thought experiment though.

Originally Posted by oil pan 4 (Post 672883)

My nearly 30 year old t56 transmission had magnets in the bottom of the case. Along with about 1/8 inch of transmission mud all along the bottom.

Originally Posted by wdb (Post 672732)

What's the point? You still need oil. Sturdy stuff too. There are heavy loads inside a gearbox, not just on the gear teeth themselves. Plus it is impossible for the gears to do their jobs at all if they don't impart force from one to the other.

Originally Posted by oil pan 4 (Post 672740)

Then they will attract iron particles and wear even faster.

Originally Posted by Logic (Post 672948)

:) Yes you would still need oil.

"impart force": Like magnetic poles repel and, according to the maths, the force with which they repel is squared as the distance between them decreases:
So Force = Magnetic Constant /Distance squared.
So the maths says; when D is 0; F is infinite, regardless of how strong the magnet is...
https://socratic.org/questions/the-f...ionality%20%23

ie: You will still get all the force/torque, but without the gears ever physically touching, much like you cant get the like poles of a bar magnet to ever touch... theoretically..?

Originally Posted by Logic (Post 672946)

Yes one gear shaft is a solid piece.
My guess was that as long as one kept all the norths in the same direction; you'd be fine.
I too looked, but couldn't find info on this. Link?

The other shaft is all separate gears. Easy enough.

And yes; Just a Thought Experiment at this stage.
:)

Originally Posted by aerohead (Post 672765)

Two things came to mind.
1) The gears are hydrodynamically lubricated. In operation, they never actually make physical contact with one another. So we'd be working on a problem that never existed in the first place.

Originally Posted by aerohead (Post 672765)

Two things came to mind
2) Secondly, if one were to magnetize the gears, they'd be in a position to attract any ferrous metal debris suspended in the gear oil.
It would in essence be like pouring 'sand' into the transmission.

Originally Posted by Ecky (Post 672950)

Unfortunately, the force is only infinite if the magnet is a point source with no physical dimensions - a bit like those physics textbook problems talking about ladders moving at the speed of light through an open barn door. Doesn't actually exist. From my reading, in practice all magnets have the center of their pole somewhere inside their structure (not at the very edge), and the pole is really only where the electromagnetic field lines converge, and it moves around depending on how it interacts with other fields. With a purely steel gear of that size, you're likely to get a few fractions of a pound of repulsive force.




I spent a few hours reading on this but didn't save any links. Best I can tell, to build this, you'd need to recast the gear where the alloyed metal in the middle is not ferromagnetic (possibly in a face centered cubic crystalline structure), while having the atoms in the teeth all aligned outward with a different crystalline structure, such as body-centered. The magnetic fiends of the different teeth would interact with each other, and there needs to be a path for the field lines to make their way around to the underside of the teeth without interference. You also risk any shocks to the gear (such as when changing gears) completely reorienting the magnetic fields. I expect this to be a multimillion dollar project to produce one set of gears, which would have a repulsive force under a pound, that might demagnetize the first time you put it in gear.

Originally Posted by Logic (Post 672958)

Well there goes one crazy idea! :)
I'm glad it caught your imagination and thx for researching it and replying Ecky.

Originally Posted by Logic (Post 672948)

:) Yes you would still need oil.

"impart force":
Like magnetic poles repel and, according to the maths, the force with which they repel is squared as the distance between them decreases:
So Force = Magnetic Constant /Distance squared.
So the maths says; when D is 0; F is infinite, regardless of how strong the magnet is...
https://socratic.org/questions/the-f...ionality%20%23

ie: You will still get all the force/torque, but without the gears ever physically touching, much like you can't get the like poles of a bar magnet to ever touch... theoretically..?

Originally Posted by Logic (Post 672712)

This is just a crazy idea I had and thought I'd put 'out there':

Take your well run in manual gearbox apart.
Wrap thick copper wire around each gear and discharge a large capacitor through the wire to magnetize the gears so the tops are north and and the bottoms south. (not left north and right south. Although that may work too)

Now all the gears are magnetized such that they repel each other when the box is put back together.

Due to the very small gaps between gear teeth the repulsive force should be substantial enough to avoid gear tooth contact a lot of the time, and greatly decrease the pressure with which the teeth push on each other all the time.

I have no idea how much difference this would make?? Research Reqd!

You'd still have to add oil. (drag. maybe thinner oil?)
Then there's the issue of all that fine metal that usually accumulates on the sump plug magnet! On a well run in gearbox..?

It'd be great if some one here knows the maths in this and can chip in so I don't have to go look it all up! :)