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Practical Magnetic Levitating Transmission Gear System Loses Its Teeth
Zothecula writes: A new transmission device that uses magnetic levitation to almost completely eliminate friction and wear has been developed as part of the MAGDRIVE research project, a collaboration of seven European nations. The creation of the unit entailed the development of a magnetic gear reducer and corresponding frictionless magnetic axles. Aimed primarily for use in spacecraft due to its extended mechanical life, the system is also adaptable for use in automobiles, railways, and aircraft.
It looks too bulky to provide a lot of gears in an automotive application, but if it could provide just two that you couldn't strip out no matter how much torque you put through them, it could be a really nice match for EVs. They would benefit from a transmission, but it's difficult for any transmission of a reasonable size to handle the output torque.
Electric cars don't need gears in the first place. The only reason we have gears in IC engines is because, 1. it would be expensive and hard to keep the engines in sync if you had a separate one for each wheel, 2. IC engines operate in most efficiently at very specific RPMs. Notice how the tachometer tends to hover around 2000 rpm as you shift gears? That's what the gears are for, to keep the engine at a constant RPM. Electric motors work just as efficiently at just about any RPM.
If your car has a CVT, it's a "Continuously Variable Transmission". The gear ratio continously varies, hence the name.
It's unrelated to the CV ("Constant Velocity") joints on the transaxle. Those are joints that maintain a constant velocity on the input and output shafts even though there is a bend in the middle, as opposed to a universal joint that has some change in angular momentum that varies based on the angle of the bend.
dom