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magnetic shocks

no wear no oil smoother ride
  [vote for,

Two magnets would repel eachother inside the shock giving a smooth ride and would never wear out. The type of ride desired would depend on the power of the magnets.
slothdawg2k, Dec 20 2000

Magnetic shock absorbers http://www.sae.org/...papers/2001-01-2071
Ongoing research: The use of magnetic shock absorbers to generate electricity from those bumps in the road. [jutta, Dec 20 2000, last modified Aug 07 2007]

Electromagnet Mattress http://www.halfbake...romagnet_20Mattress
Similar mattress idea [hippo, Dec 20 2000, last modified Oct 04 2004]

Stuff about MagLev Trains http://www.theage.c...18/FFX00Y8P1OC.html
Not directly on the original topic, but addresses some of Odayaka's ideas [RobRoy, Dec 20 2000, last modified Oct 21 2004]

speedyguy's link http://sellisengine...com/magneshock.html
as a link [squigbobble, Apr 30 2005]


       The French have been doing research on magnetic trains for quite a while. One of the advantages of these trains is in fact reduced bumps, friction and interia (by putting the train on an angle during turns). The French got to the point of building a 100km magnetic railroad and it worked (though the electromagnets needed to be cooled at over -100 degrees centrigrade) but the system was never actually used because simulations showed that if the train shut down and that there was a 100km/h latteral wind it would fall over.   

       In Shanghai, construction of a magnetic railroad has begun and I'm not sure how they got over this problem (or maybe just ignored it?). But one of the major issues with using electromagnets is that they require considerable amounts of power especially for something on the weight scale of a train or car.   

       One of the advantages of cars though is that the're much shorter than trains and probably wouldn't be flipped over with 100km/h latteral winds. Maybe roads could be equipped with magnetic tracks? Might be cause for cold feet though, as you step out of your car.
Odayaka, Aug 22 2001

       That sounds like you're describing a magnetic spring, not a magnetic shock absorber. (People often confuse springs and shocks.) This highlights the problem with magnetic suspensions, which is that they're infinitely bouncy, which isn't what you want.   

       A magnetic shock absorber could perhaps be made with a magnet inside an aluminum tube, or with sophisticated computer-controlled electromagnets designed to dampen vibrations.
egnor, Sep 25 2001

       put more than two mag in a tube so shock, spring... whatever is absorberd even more (=[+-] [-+] [+-] [-+] [+-]= etc..) (like my diagram =) electricity could run throw a tube souronding the magnets, but this puts more drain on car batt, if your batt dies or goes low so does your shocks...
i-Mer, Feb 21 2002

       i have an idea for the problem with the magnets repeling to fast thus making them a smoother ride if anyone is interested let me know
lad, Sep 25 2002

       First, go look up "damping" and "spring" and notice the difference (phase!).   

       Magnet forces are too weak to *suspend* a car in the space available.   


       Given Bmax of 1.5 you get a maximum "magnetic pressure" of about 20bar. Hydraulic shocks generate 100s of bar at peak velocity, hence their small cross section. Your "shock" would be massive. This is a *basic* limitation of magnetics and the reason why a hydraulic pump is so much smaller than a matched electric motor.   

       Magnets in repulsion or attraction are also extremely non-linear and anyway the travel is too long.   

       But there are some uses for magnetics in car suspensions, to control damping constant:   

       1. Modulate the viscosity of a magneto-rheological fluid in an otherwise standard fluid damper.   

       2. Actuate a proportional hydraulic throttle valve (see numerous baked active suspension system eg Husco)   

       3. Use radial electromagnets to excite eddy currents in a tube creating a electrically controlled damper (this is definitely possible, I developed an actuator for a variable pitch turbine based on this principle). This way your damping is generated in "magnetic shear" over the whole surface area of the tube. Though I still doubt very much you would get the damping constant required at those low velocities with a reasonably sized/powered system.
shameless_self_reference, Sep 25 2002


speedyguy, Aug 05 2003

       [speedyguy] I didn't even have to read all of that article to know that it was a magnetorheological fluid system, the power consumption is a dead giveaway. They don't work by magnetic repulsion.
squigbobble, Apr 30 2005

       What if you don't want to drive due north?
Basepair, Apr 30 2005

       Darn! Yet again, someone has beaten me to a good idea. I think this might work, although you might have to use a whole lot of very powerful (and thus very expensive) magnets to get enough force to suspend a car. The advantage is that it would never wear out the way coil springs would. The only big problem would come if you hit a really big bump and shattered the magnets.
discontinuuity, Nov 28 2005

       Nice idea, even though it won't work for all the reasons given above. You'd also collect a lot of ferromagnetic junk as you drove along (including dropped small change).
wagster, Nov 28 2005

       we should try for magnetic suspensions
rohitchilli, Aug 07 2007

Custardguts, Nov 22 2007


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