The early form of linear motion bearing is to place a row of wooden poles under a row of skids. Modern linear motion bearings use the same working principle, but sometimes use balls instead of rollers. The simplest rotary bearing is the sleeve bearing, which is just a bushing clamped between the wheel and the axle. This design was subsequently replaced by rolling bearings, in which many cylindrical rollers were used to replace the original bushings, and each roller was like a separate wheel.
An early example of a ball bearing was found on an ancient Roman ship built in 40 BC, which was found in the Italian Lake Nami: a wooden ball bearing was used to support a rotating table. It is said that Leonardo da Vinci once described a ball bearing around 1500. Among various immature factors of ball bearings, one of the most important is that the balls will collide with each other, causing additional friction. But you can prevent this phenomenon by putting the ball into small cages. In the 17th century, Galileo first described the ball bearing of "cage ball". At the end of the seventeenth century, C. Warlow of England designed and manufactured ball bearings, which were installed on mail cars for trial use, and P. Worth of England obtained a patent for ball bearings. The earliest practical rolling bearing with cage was invented by watchmaker John Harrison in 1760 for making H3 hour meter. At the end of the 18th century, H.R. Hertz of Germany published a paper on contact stress of ball bearings. On the basis of Hertz's achievements, R. Stribeck of Germany, A. Palmgren of Sweden and others carried out a large number of tests, which contributed to the development of the design theory and fatigue life calculation of rolling bearings. Later, Russian N.P. Petrov applied Newton's viscosity law to calculate bearing friction. The first patent on the raceway was obtained by Philip Vaughn of Camasson in 1794.
In 1883, Friedrich Fisher put forward the idea of using appropriate production machines to grind steel balls with the same size and accurate roundness, which laid the foundation for the bearing industry. O. Reynold of England made a mathematical analysis of Torr's discovery and derived Reynold's equation, which laid the foundation of hydrodynamic lubrication theory.
