Scientists Have Created New High-Tech 'Fluid Gears' That Can Rotate Without Making Contact

Many mechanical devices run on gears. Even the most reliable electric vehicles have simple gears that transmit motor torque to the wheels. However, the constant friction gears experience due to their continuous contact (the grinding of gears, one might say) results in a ton of wear and tear. Scientists might have found a solution to this age-old problem thanks to fluid dynamics.

In January 2026, researchers at New York University and NYU Shanghai revealed they had invented a new type of gear that is completely contactless — at least with other gears. According to the study (which was published in Physical Review Letters), this novel style of cylindrical gear can influence the movement of other gears by "spinning up fluid," specifically a "glycerol-water solution" with controllable viscosity and density. Oh, and bubbles to monitor the fluid's flow. This liquid essentially serves as the gear's teeth.

The researchers discovered that when one gear (cylinder) was spun close enough to an immobile one, the active gear produced a fluid flow that could "grip" the passive gear and make it spin in the opposite direction. You might expect that this mechanism would only be effective up to a certain distance, and you'd be half right; if the active gear's speed was increased, the far-away one would start spinning in the same direction, similar to how pulley systems work. It might be simple, but hey, that's how smart homes functioned before the microchip.

You may be wondering what advantages these new "fluid gears" have over standard gears. One of the researchers, Leif Ristroph (Associate Professor of Mathematics at NYU's Courant Institute School of Mathematics, Computing, and Data Science) stated it comes down to the limitations of standard gears. According to Ristroph, normal gears need teeth that "mesh just right," and any flaw or even external crumb can make them jam, whereas fluid gears don't have these issues. In fact, their speeds and directions can change "in ways not possible with mechanical gears."

That's all well and good, but what do we need with gears that never break or jam? One potential market is soft robots (robots that use flexible components instead of hard ones). Imagine, if you will, a future where a soft robotic system packs your groceries, and instead of using a standard gear train, the robot utilizes fluid gears that can adjust gear ratios on the fly without risk of jamming or potentially damaging its components.

Of course, these gears were recently invented, and while the original study paper outlines potential applications, we will require more time to fully understand the limitations of this nascent technology. Fingers crossed these gears can be used to create bicycles with "chains" that never snap or dislocate — assuming engineers can build a fluid container that can stand up to the rigors of bicycling.