The small parts that Leonardo da Vinci drew 500 years ago now support the joints of AI robots

I. A Genius Design Forgotten for 300 Years: A Bearing Prototype Hidden in a Manuscript

In 1967, while sorting ancient books, staff at the National Library of Spain stumbled upon two dusty notebooks—the Madrid Manuscript I. As the researchers carefully unfolded the yellowed pages, a seemingly simple mechanical sketch left the audience speechless: spherical objects neatly arranged between two metal disks. Even more astonishingly, these "balls" were neatly separated by a circular frame, virtually identical to the ball bearings found in modern factories. This design, created between 1493 and 1497, predates the first bearing patent obtained by Welsh inventor Philip Vaughan by nearly 300 years. At a time when sliding friction sleeves were still used, Leonardo da Vinci had accurately anticipated the core principle of "rolling friction replacing sliding friction" and even pioneered the inclusion of a "cage" to prevent ball collision and wear. This structure remains one of the three core components of a bearing (raceway ring, rolling element, and cage).

II. More Than Just Drawings: Reflections on Leonardo da Vinci's "Friction Revolution"

The greatness of this Renaissance master extended far beyond his mere drawings. In his densely packed Latin manuscript, the Madrid Manuscript I, he systematically studied friction: "The degree of wear on a surface is directly proportional to the pressure and inversely proportional to the contact area." He even experimentally calculated the coefficient of friction for different materials, conclusions that align remarkably with empirical data from modern tribology. His original motivation for designing bearings was to address the power loss problem of another of his inventions: the human-powered helicopter. Although his "helicopter," made of linen and reeds, failed to take off due to insufficient material strength, the principle of "efficient force transmission" embodied in the bearing design laid the seeds for modern machinery. Leonardo da Vinci predicted in his notebooks: "These small balls will make heavy machinery light, as if giving it wings." Today, everything from bicycle wheels to aerospace engines bears out this assertion.

III. History's Regret: Why did a brilliant design lie dormant for 300 years? 

Although Leonardo da Vinci's bearing design was theoretically perfect, it was relegated to mere theoretical speculation in his time. The key bottleneck lay in materials and manufacturing processes: 15th-century blacksmiths were unable to forge uniformly sized steel balls, and lacked the precision machining equipment to guarantee the roundness tolerances of the raceways. It wasn't until the Industrial Revolution of the 18th century, and the demand for standardized production brought about by steam engines, that Philip Vaughan successfully applied a similar design to carriage axles in 1794, ushering in the industrial age of bearings. Even more lamentable was the lack of a patent system. During the Renaissance, intellectual property protection was largely unheard of. Leonardo da Vinci's manuscripts were mostly private research notes. Following his death in 1519, many of his designs were forgotten in the corners of libraries. Vaughan, along with Henry Timken, who later invented the tapered roller bearing, though standing on the shoulders of giants, was later hailed as the "Father of Bearings" for their contributions to patents and mass production.
IV. A Tribute Across Time and Space: From Manuscripts to AI Robotic "Joints"

When modern engineers open Leonardo da Vinci's manuscripts, they are often amazed by the forward-thinking nature of his designs. The Japanese company JTEKT has recreated his bearings at a 1:1 scale. Testing has shown that this cage-type bearing reduces friction losses by 70% compared to contemporary plain bearings. In today's intelligent era, da Vinci's wisdom is being passed down in even more striking ways: • In the medical field: Intuitive Surgical's "da Vinci" surgical robot uses porous bronze sliding bearings in its robotic arm joints, with an oil-retention structure with a pore size of just 20 microns. This aligns with the idea of "using grease to reduce friction" in da Vinci's notebooks, allowing surgical precision to be controlled within 0.02mm; • In the aerospace field: The Mars rover's drive wheel bearings use graphene self-lubricating technology, with a friction coefficient as low as 0.008. This "extreme environment adaptation" design logic coincides with da Vinci's design of dust-proof bearings for war machines; In the industrial field: The Tesla Optimus robot alone is equipped with over 100 precision bearings. The core structure of these "mechanical joints" still adheres to the three elements of "raceway - rolling element - cage" defined by da Vinci.

Ⅴ. Genius's Revelation: True Innovation is Never a Flash of Inspiration

Leonardo da Vinci wrote in his notebooks: "All innovations originate from the observation of nature and the deconstruction of its principles." He observed that rolling wheels require less effort than sliding, which led him to abstract the principle of rolling friction. The orderly movement of bird wings led him to conceive the structure of cage dividers. This "phenomenon-to-essence" approach to thinking is more worthy of inheritance than bearing design itself. Today, the global bearing market has exceeded $100 billion. From mobile phone vibrating motors to wind turbines, these inconspicuous components underpin the operation of modern industry. As we marvel at the agile movements of AI robots, perhaps we should remember the genius who worked at his desk 500 years ago—the tiny ball bearings he drew have rolled through the dust of history and into a more sophisticated future.