Bearings for home-built gyroscope?

[Amateur -1]

Yes I know they have magnetically levitated trains.

I know they are expensive.

They are expensive because they are complicated.

If you could make them work without being complicated they would be cheaper.

The people who buy trains do not want them any more expensive than they need to be.

So the people who make them complicated do that because that can not make them simple.

If your idea for a bearing worked then it would be simple and cheap and so people would use it. They don't.

So your idea does not work.

Magnetic bearings do work, but they are much more complicated than your idea.

 

Dear 'John Cuthber'

 

1. I only told you about the trains doe to they are magnetically Levitated

 

2. What I was talking being costly is the off the self Magnetic bearings.

 

3. Back in the early 90's The HIA [Houston Inventors Association] members

 

gave magnetic barring gyro kits for the Schools class's to put together.

 

What you see here is just some of the parts in the kits. Along with my Ids for HIA.

 

These Kits came Hobby Lobby. This when I made my gyro.

 

Edited May 8, 2012 by Amateur -1

[John Cuthber]

Great! Now you can tell us how well they cope with radial loads.

Incidentally, what is the nylon/plastic for in your diagram?

Edited May 8, 2012 by John Cuthber

[Amateur -1]

Great! Now you can tell us how well they cope with radial loads.

Incidentally, what is the nylon/plastic for in your diagram?

 

 

 

 

These Kits came Hobby Lobby.

 

This when I made my gyro.

 

I made mine a little bigger just to see if I could

 

And it did work ,but I do not have the

 

means to do test any kind testing.

 

But, just my be you can see it now.

 

What is the nylon/plastic for in your diagram?

 

They hold the bottom and top magnets and align the shift magnets

 

so the magnets a prose each other. Making it float on the fields.

Edited May 8, 2012 by Amateur -1

[doG]

Amateur -1

 

Well the one that I made was made from a 9" flywheel off a out board motor and was about 3.5Lb.

And I can assure you the that ½ in. By 3/8^th. thick button magnets are strong enough that you can not

 

 

pull the apart & for sure that you and a friend would be able push them together.

OK, that hints at the axial load capability and says nothing of the radial load question I raised. Do you understand the difference between axial and radial loads?

[John Cuthber]

I think it's plain that he doesn't realise that, for his design, the radial loads are taken by the nylon.

That's fine for a toy, but with a big, fast rotor they wouldn't cope. They would overheat and melt in much the same way as, for example, cheese.

 

That's why proper magnetic bearings are expensive and complicated: they have to deal with radial and mixed loads.

[doG]

I think it's plain that he doesn't realise that, for his design, the radial loads are taken by the nylon.

That's fine for a toy, but with a big, fast rotor they wouldn't cope. They would overheat and melt in much the same way as, for example, cheese.

 

That's why proper magnetic bearings are expensive and complicated: they have to deal with radial and mixed loads.

I realize that. That's why my next question was how much radial or centrifugal force would be created if a 1kg mass with a 150mm radius moving at 20,000 rpm was 1g out of balance

[John Cuthber]

Another interesting one would be to calculate the forces if you tried to turn it upside down (WRT the set up in the digram) say in 1 second assuming the shaft length is the same as the rotor diameter Feel free to make such other assumptions as you see fit.

[THX-1138]

How well does that handle radial loads?

 

Hmm. If the sleeve is Teflon™ or some low-friction high-temperature plastic, and it's supported by being sunk press-fit into the gimbal frame, this might work really well.

[doG]

Hmm. If the sleeve is Teflon™ or some low-friction high-temperature plastic, and it's supported by being sunk press-fit into the gimbal frame, this might work really well.

Do understand that PTFE or any high temperature plastic is going to have a compressive yield point where the radial load will extrude the material. You should examine the forces John and I mentioned above and compare them with the mechanical properties listed here. IMO, this approach to the design would become a lesson on how not to build a gyroscope.

[Externet]

For ~$10, a Sunon computer fan could be canibalized for its magnetic suspension technology; perhaps can be applied on your project.

 

http://www.sunonusa.com/index2.asp?f=technology&p=maglev

 

Another brand is Enermax:

 

http://www.digitaldingus.com/reviews/enermax/warpenlobal/index.php

[doG]

The application is a fairly massive gyroscope (I'm guessing the rotor is about 1kg) spinning at whatever RPM I can safely manage. The bearings are to mount the spindle in the inner gimbal, so they need to be able to support the axial thrust and provide low-friction support of the spindle rotation. And be strong enough to support the precession forces if the gimbal is locked and an attitude change is attempted....

 

 

For ~$10, a Sunon computer fan could be canibalized for its magnetic suspension technology; perhaps can be applied on your project.

 

http://www.sunonusa.com/index2.asp?f=technology&p=maglev

 

Another brand is Enermax:

 

http://www.digitaldingus.com/reviews/enermax/warpenlobal/index.php

 

I'm kind of thinking that Sunon thing is probably not going to do well with a 1kg rotor but maybe I'm missing something here. Could you fill me in on the blanks Externet?

[THX-1138]

For ~$10, a Sunon computer fan could be canibalized for its magnetic suspension technology; perhaps can be applied on your project.

 

http://www.sunonusa.com/index2.asp?f=technology&p=maglev

 

Looking at the diagram and description, I must not understand how it works. Unless the 'magnet plate' is an active rather than a passive element, I would expect all sorts of issues with eddies and other induction effects in the plate. And I'm not seeing the fields being used for repulsion, which is what I associate with the term 'mag lev,' but with attraction for stabilisation. I'm seeing not a magnetic bearing, but magnets used to reduce wear on a more conventional bearing.

 

Or am I all wet?

[Rina]

A great article on bearings: http://www.mechanicaldesignforum.com/content.php?82-Ball-Bearings-Guide-to-selection-applications-calculations

 

I would say these would be okay: https://www.mrosupply.com/bearings/bearing-sleeve/2176959_ah2313_fag-bearing/