The sleeves made of anti-friction materials in sliding bearings are also called bearing bushings and bushings. It is usually cast on the inner surface of the bearing bush, mainly to reduce costs and save valuable wear-reducing materials. Thickness 0.5-6mm, used for large size or important bearings. The bearing bushing mainly replaces the wear of the shaft, and also supports the operation of the shaft, reduces friction and wear, and reduces vibration.
The earliest sliding and rolling element bearings were made of wood. Ceramic, sapphire or glass are also used, and steel, copper, other metals, and plastics (such as nylon, bakelite, Teflon, and UHMWPE) are commonly used.
From heavy-duty wheel axles and machine tool spindles to precision watch parts, rotating bearings are needed in many applications. The simplest swivel bearing is a sleeve bearing, which is just a bushing sandwiched between the wheel and axle. This design was later replaced by rolling bearings, which replaced the original bushings with many cylindrical rollers, each rolling element acting like a separate wheel. The first rolling bearing with a cage that was put into practical use was invented by watchmaker John Harrison in 1760 to make the H3 chronograph.
An early example of a ball bearing was found on an ancient Roman ship found in Lake Nami, Italy. This wooden ball bearing is used to support the rotating tabletop. This ship was built in 40 BC. Leonardo da Vinci is said to have described a ball bearing around 1500. Among the various immature factors of ball bearings, a very important point is that the balls will collide with each other, causing additional friction. But you can prevent this phenomenon by putting the balls into small cages. In the 17th century, Galileo Galileo made the earliest description of "fixed ball" or "cage ball" ball bearings. But for a long time, the installation of bearings on the machine has not been realized. The first patent for a ball channel was obtained by Philip Vaughan of Carmarthen in 1794.
In 1883, Friedrich Fischer proposed the idea of ??using suitable production machines to grind steel balls of the same size and accurate roundness. This laid the foundation for the creation of an independent bearing industry. The initials "Fischers Automatische Gu?stahlkugelfabrik" or "Fischer Aktien-Gesellschaft" later became a trademark, registered on July 29, 1905. In 1962, the FAG trademark was modified and is still in use today, and became an integral part of the company in 1979.
In 1907, Sven Wingquist of the SKF bearing factory designed the earliest modern self-aligning ball bearing.