Progress in Magnetic Gearing for Aeronautics and Space Applications

Magnetic gears harness the magnetic force between non-contacting sets of permanent magnets. They achieve a gear ratio through the geometry and constrained motion of the magnets or the transformation of the magnetic fields by carefully shaped soft magnetic material. Their non-contact nature eliminates the need for gear lubrication and the wear mechanisms associated with mechanical contact. Magnetic gears have the potential to reduce the strong, tonal vibration and noise that is inherent to mechanical gears. Magnetic gears are also easily integrated into electric machines because they rely on the same physics and utilize the same materials and many of the same components. For these reasons and the invention of higher performing magnetic gear configurations over the past 20 years, magnetic gears have received growing attention for aerospace applications. This presentation summarizes the motivation for studying magnetic gears and the progress made in developing the technology to meet the demanding requirements of aerospace applications. The focus is on the development completed and ongoing at NASA, but SBIR projects in the field are summarized. The discussion focuses on the application of magnetic gears and magnetically-geared motors in electrified aircraft propulsion systems and actuation systems for space mechanisms. The NASA work includes the design, optimization, and testing of magnetic gears and magnetically-geared motors for electrified vertical takeoff and landing aircraft and the design and ambient environment testing of a magnetically-geared actuator for use in extremely cold and dusty space environments. The presentation concludes with thoughts on the technical barriers to adoption and potentially fruitful topics for future research.