Ball Bearing (Rolling-Element Bearing)

Rolling-element bearing using spherical balls between inner and outer raceways to minimize rotational friction under load.

Specifications & Metrics

type: Mechanical Power Transmission
governing equation: L₁₀ = (C / P)³ × 10⁶ revolutions (Lundberg–Palmgren fatigue life equation)
primary function: Low-friction shaft rotation supporting combined radial and axial loads
key parameters: Dynamic load rating (C), contact angle (0°–45°), elastohydrodynamic lubricant viscosity
originator: Philip Vaughan (1794 axle groove patent), Jules Suriray (1869), Sven Wingqvist (1907 self-aligning)

Patented in modern grooved-axle form by Welsh ironmaster Philip Vaughan in 1794 and refined with Robert Conrad's 1903 eccentric-loading caged deep-groove design and Sven Wingqvist's 1907 self-aligning spherical raceway, ball bearings replace sliding friction with rolling contact.
Under the 1947 Lundberg–Palmgren metal-fatigue relation, a ball bearing's L₁₀ rating life (the revolutions survived by 90% of a bearing population) is inversely proportional to the cube of the equivalent applied load.
High-speed turbine and aerospace spindles use hybrid angular-contact bearings pairing steel races with silicon nitride (Si₃N₄) ceramic balls that weigh 60% less than steel, cutting centrifugal outer-race loading and enabling 20–40% higher rotational speeds.