In the early form of linear motion bearings, a row of w […]
In the early form of linear motion bearings, a row of wood poles was placed under a row of rafts. Modern linear motion bearings use the same principle of operation, except that balls are sometimes used instead of rollers. The simplest rotary bearing is a bushing bearing, which is simply a bushing sandwiched between the wheel and the axle. This design was subsequently replaced by a rolling bearing that replaced the original bushing with a number of cylindrical rollers, each rolling body being like a separate wheel.
An example of an early ball bearing was found on an ancient Roman ship built in Lake Nami, Italy, built in 40 BC: a wooden ball bearing is used to support the rotating table top. It is said that Leonardo da Vinci described a ball bearing around 1500. Among the various immature factors of ball bearings, it is important that collisions occur between the balls, causing additional friction. But this can be prevented by putting the ball in a small cage. In the 17th century, Galileo made the earliest description of the "cage ball" ball bearing.
At the end of the seventeenth century, the British C. Vallo designed and manufactured ball bearings, and installed on the mail truck trial and the British P. Worth patented ball bearings. The first practical rolling bearing with cage was invented by watchmaker John Harrison in 1760 for the production of the H3 chronograph. At the end of the eighteenth century, H.R. Hertz of Germany published a paper on the contact stress of ball bearings. On the basis of Hertz's achievements, R. Stebbeck of Germany and A. Palmer of Sweden conducted a large number of experiments, which contributed to the development of the design theory and fatigue life calculation of rolling bearings. Subsequently, N.P. Petrov of Russia applied Newton's law of viscosity to calculate bearing friction. The first patent on the ball channel was obtained by Carmarthen's Philip Vaughan in 1794.
In 1883, Friedrich Fisher proposed the use of a suitable production machine to grind steel balls of the same size and roundness, laying the foundation for the bearing industry. The British O. Renault conducted a mathematical analysis of Thor's discovery and derived the Reynolds equation, which laid the foundation for the fluid dynamic lubrication theory.