Practical magnetic levitating transmission gear system loses its teeth
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 we looked at back in 2010. 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.
Researchers from the Universidad Carlos III de Madrid (UC3M) created the magnetic drive system reducer in response to a problem of mechanical wear initially posed by the European Space Agency (ESA), where conventionally-connected gears, axles, and drive shafts remain problematic due to their lubrication requirements and relatively short life spans.
"The operating life of these devices can be much longer than the life of a conventional gear reducer with teeth, and can even work in cryogenic temperatures," said Efrén Díez Jiménez, a researcher from the UC3M Department of Mechanical Engineering. He added that even after an overload, the device will continue to function. And if the axle is blocked, “the parts simply slide amongst themselves, but nothing breaks."
To demonstrate their device, the UC3M researchers created two prototypes. The first is designed for use in space, and is a cryogenic model that keeps the axles floating via levitating superconductor bearings that work at a temperature of around -210° C (-346° F) in a vacuum. The superconducting magnet also helps stabilize the rotating parts to prevent oscillating motions or imbalances.
Prototype number two is designed to be used at room temperature. In this case, the magnetic reducer sees the gear teeth replaced with permanent magnets that repel and attract each other so that "the transmission of couples and forces between the moving parts with contact is achieved."
According to the researchers, the second prototype may be used in any area where standard mechanical gear reducers are employed, such as in machinery for railroads, the oil industry, or in engineering applications in general. The researchers also believe that the lack of any lubricants would make the gear system especially suitable for sterile applications, such as those found in the pharmaceutical, biomedical, and food production areas.
As for space applications, Jiménez says applications for the technology range, "from robot arms or antenna positioners, where high-precision movements are needed or when contamination from lubricants is undesired, to vehicles that, because of temperature or extreme conditions of absence of pressure, shorten the life of conventional mechanisms, as happens with the wheels of a Rover that has to go on Mars."
Despite the fact that the cryogenic superconductor prototype addressed the problem posed by ESA, it is the prospect of using a frictionless drive at ordinary temperatures and in everyday situations that will likely have the most appeal.
"No doubt the room temperature prototype is the one that can have the biggest impact and industrial application," said the researchers.
A spin-off company called MAG SOAR has also been created to explore commercial exploitation of technologies arising from this project. Presented at a number of different conferences organized by ESA, NASA, and the American Society of Mechanical Engineers, the results of the MAGDRIVE research have also been published in the Journal of Engineering Tribology.
The video below shows the superconducting cryogenic magnetic device in action.