Leonardo da Vinci drew an early ball bearing to reduce friction between moving surfaces.
The design appears in studies dating to the late 15th century and uses balls held between rings or tracks. As the parts move, the balls roll rather than allowing one surface to slide directly over another. That principle reduces friction and can make rotating machinery more efficient.
Leonardo’s drawing is frequently called an early ball-bearing design, but it was not a modern standardized bearing. His sketches explored several arrangements, and manufacturing precise, durable components remained difficult in the Renaissance. The basic concept nevertheless resembles the rolling-element bearings later developed for clocks, machines, vehicles, and industrial equipment.
Bearings were especially relevant to Leonardo because he investigated gears, shafts, pulleys, and other mechanisms. A bearing does not provide power by itself; it supports a rotating or moving part while limiting resistance. This distinction separates it from a gear, which transfers motion and torque.