Leonardo da Vinci drew a ball bearing using rolling spheres to reduce friction between moving surfaces.
His sketches show balls arranged so that one ring or surface could move against another with rolling contact instead of sliding contact. Rolling reduces friction because the contact surfaces do not have to scrape across one another in the same way.
The drawing appears in Leonardo’s studies of mechanics and is often cited as an early ball-bearing concept. It was not a complete modern bearing specification, and Leonardo did not create the standardized, sealed bearings used in machines today.
Ball bearings are sometimes confused with gears because both can transmit or support motion. Gears have teeth that mesh to transfer rotation, whereas bearings support moving parts and reduce resistance. Leonardo’s design concerns support and friction reduction.