http://www.engineerlive.com/Design-Engineer/Power_Transmission/Magnets_offer_advantages_as_an_alternative_to_mechanical_gears/22078/
No, it's an additional system.etard said:So is this just basicly a multi layered motor like Luke is proposing in the axial flux thread with different windings and the motor just switches between two different winding counts to get the desired motor speed?
It's already covered by patents, that's why they're free to.........fireraisr said:Amazing that they would publish a video with such detailed conceptual and structural info. I bet someone with a fair amount of mechanical and machining know how could replicate this in a shop. Shoot, I may want to have a crack at it myself when I finish my upper division physics classes.
Miles said:It's already covered by patents, that's why they're free to.........fireraisr said:Amazing that they would publish a video with such detailed conceptual and structural info. I bet someone with a fair amount of mechanical and machining know how could replicate this in a shop. Shoot, I may want to have a crack at it myself when I finish my upper division physics classes.
fireraisr said:Amazing that they would publish a video with such detailed conceptual and structural info. I bet someone with a fair amount of mechanical and machining know how could replicate this in a shop. Shoot, I may want to have a crack at it myself when I finish my upper division physics classes.
Low ratio is up to 50:1!:Contactless, high-efficiency, high-torque transmission with inherent overload protection
The high-torque magnetic gear was invented and demonstrated by Magnomatics co-founder Dr Kais Atallah in 2001. This pioneering research has been extended by Magnomatics to provide a mature range of gear technologies that are suitable for a very wide range of applications.
Advantages over mechanical gears
* Reduced maintenance and improved reliability
* Lubrication free
* Higher efficiency than conventional gears
* Precise peak torque transmission and inherent overload protection
* Physical isolation between input and output shafts
* Inherent anti-jamming transmission
* Significantly reduces harmful drivetrain pulsations
* Allows for misalignment/vibration of shafts
* Very low acoustic noise and vibration
A magnetic gear uses permanent magnets to transmit torque between an input and output shaft without mechanical contact. Torque densities comparable with mechanical gears can be achieved with an efficiency >99% at full load and with much higher part load efficiencies than a mechanical gear. For higher power ratings a magnetic gear will be smaller, lighter and lower cost than a mechanical gear. Since there is no mechanical contact between the moving parts there is no wear and lubrication is not required. Magnetic gears inherently protect against overloads by harmlessly slipping if an overload torque is applied, and automatically and safely re-engaging when the fault torque is removed.
Magnomatics has developed a range of magnetic gear technologies for achieving low and high ratios and a linear gear variant. The magnetic gear concept has been extended to provide both an ultra high torque density pseudo direct drive electrical machine and a variable ratio gear topology for continuously variable transmission systems.
http://www.magnomatics.com/Technology/Magnetic-CVT.aspxContactless high-torque magnetic gears with ratios of less than 50:1 with inherent overload capability
A low ratio magnetic gear uses a series of steel pole-pieces to modulate the fields produced by two permanent magnet rotors with different numbers of magnetic poles. The magnet arrays rotate at different speeds with the gear ratio determined by the ratio of magnets in each array. The transfer of motion between input and output shafts is passively achieved using just high power permanent magnets.
A high degree of magnetic coupling between the rotors allows for torque densities comparable with mechanical gears to be realised. Gear ratios of 50:1 down to 1.01:1 with almost zero torque ripple are readily achievable. The low ratio magnetic gear forms an integral component within Magnomatics’ new type of permanent magnet machine, the ultra high torque density pseudo direct drive, PDD®.
Low ratio magnetic gears can be realised in a conventional radial field or in an axial arrangement when a thin “pancake†design is required. Unlike conventional mechanical gears the magnetic gear can be arranged to provide geared linear movement.
Contactless, high efficiency continuously variable transmission system with inherent overload protection
Advantages
* High efficiency
* Contactless, lubrication-free variable transmission
* Inherent overload, torque fuse capability
* Speed of prime mover matched with variable speed load
The high torque density low ratio magnetic gear concept has been extended by Magnomatics to create a variable ratio magnetic gear which can be used as an integral component in a continuously variable transmission (CVT) or Infinitely Variable Transmission (IVT). The magnetic CVT allows a variable speed drive to be connected to a fixed speed load, is highly efficient and compact, requires no cooling or lubrication and is suitable for applications as diverse as hybrid vehicles and wind turbines.
Yeah I had an idea for something like that sometime last year. It's basically a U-shaped solenoid and the bike rim has permanent magnets fixed to it. The problem is low torque but high speeds, I thought it would be good for a roady style bike. I got the idea thinking of ways to replicate the japanese electric motorcycle prototype that was shown a few years back.amberwolf said:Well...actually... how about a magnetic "friction drive". Put magnets on the rim similar to what they seem to be using for their magnetic gearing, with a drive "gear" that engages and pulls them along. Do this on both sides of the rim. Then you can keep the whole thing narrow for a bike, assuming the motor is forward (or aft) of the wheel, rather than to the side of it.
dequinox said:
Freaking cool! Now all we need is magnetic chain drives!! :lol:
kfong said:I wonder if external power is actually needed if you just want a fixed gear setup. Seems like a simple fixed gear setup can be done this way like the first half of the video without adding power.
Improved field strengths and design techniques mean that smaller and lighter magnets can replace larger composite magnets or create new opportunities.…
Magnomatics' magnetic gears use permanent magnets to transmit torque between an input and output shaft…
paultrafalgar said:dequinox said:
Freaking cool! Now all we need is magnetic chain drives!! :lol:
If you know me, you will know that I like to throw in daft ideas in case some genius is listening and can use it as lateral thinking fodder.
So, dequinox's "daft idea" suggests this to me:
If you had a rubber belt with a continuous series of magnets stuck on the outside, with the said belt arranged just like an ordinary bike chain over chainring (toothed to engage with belt) at the front and "derailleur" at the back (maybe 3 toothed cogs to engage belt), you could have a tube around the top of the belt with electromagnets imbedded in it and a controller that would switch them on and off in such a fashion to drive the belt forward (bit like a linear motor).
No need for dual freewheels at the rear and no need for a secondary system separate from the pedal-power transmission. Regeneration is easy and "cogging" is no problem, because when you aren't using the motor the electromagnetic coils are not energised.
What do you think?
liveforphysics said:What they neglect to mention are the eddy current losses.
Those magnet holders an anything in motion through the magnetic fields, or anything with magnetic fields in motion against it all must be non-conductive or this thing is a giant eddy current brake.
Every one of the models shown would make excellent heaters, but very poor efficiency gear reductions for things moving in the 4 digit RPM range.
liveforphysics said:Those magnet holders an anything in motion through the magnetic fields, or anything with magnetic fields in motion against it all must be non-conductive or this thing is a giant eddy current brake.
Every one of the models shown would make excellent heaters, but very poor efficiency gear reductions for things moving in the 4 digit RPM range.
Even accounting for some degree of hype you would think the efficiency should at least be somewhere in the ballpark of mechanical gears.magnomatics said:Higher efficiency than conventional gears…
Torque densities comparable with mechanical gears can be achieved with an efficiency >99% at full load and with much higher part load efficiencies than a mechanical gear. For higher power ratings a magnetic gear will be smaller, lighter and lower cost than a mechanical gear.…
A high degree of magnetic coupling between the rotors allows for torque densities comparable with mechanical gears to be realized.…
liveforphysics said:It's kinda neat, but when a gear stage can easily (and normally does) last the life of the vehicle with no hassles, and each gearing stage is also in the 98-98.5% range, and you can make it from, and locate it near metal/conductive parts, I just don't see much appeal.
Even if the efficiency is worse than mechanical gears they could be very very useful.magnomatics said:Very low acoustic noise and vibration…
Gear ratios of 50:1 down to 1.01:1 with almost zero torque ripple are readily achievable.…
For higher power ratings a magnetic gear will be smaller, lighter and lower cost than a mechanical gear…
Low ratio magnetic gears can be realized in a conventional radial field or in an axial arrangement when a thin “pancake†design is required.