Leonardo da Vinci drew a ball bearing as balls moving between two rings to reduce friction.
His sketches, made around 1498, show the basic idea of placing rolling balls between concentric surfaces. Instead of allowing one surface to slide directly against another, the balls roll between them, reducing friction and helping rotary motion. The design is associated with Leonardo’s studies for a machine that may have included a rotating platform.
Leonardo did not invent every later feature of modern ball bearings. His drawings show an early conceptual understanding, but they lacked practical cage designs that keep the balls evenly spaced. Without a cage, the balls can rub against one another and collect in a cluster, reducing efficiency.
Modern ball bearings use carefully manufactured rings, hardened balls, cages, seals, and lubricants. They appear in vehicles, electric motors, bicycles, and industrial machinery. Leonardo’s importance lies in recognizing the value of rolling contact centuries before mass-produced precision bearings became possible.