Car wheel bearings are maintenance-free bearings, but some can be maintained manually.

Bearing is an important component in contemporary mechanical equipment. Its main function is to support the mechanical rotating body, reduce the friction coefficient during its movement, and ensure its rotation accuracy.

According to the different friction properties of moving components, bearings can be divided into two categories: rolling bearings and sliding bearings. Among them, rolling bearings have been standardized and serialized, but compared with sliding bearings, their radial size, vibration and noise are larger, and their prices are also higher.

Rolling bearings generally consist of four parts: outer ring, inner ring, rolling elements and cage. According to the shape of the rolling elements, rolling bearings are divided into two categories: ball bearings and roller bearings.

Basic information

Bearing ("Bearing", Japanese people call it "shaft bearing") is a component that fixes and reduces the load friction coefficient during mechanical transmission. It can also be said that when other parts move relative to each other on the shaft, it is a part used to reduce the friction coefficient during power transmission and keep the center position of the shaft fixed. Bearings are an important component in contemporary mechanical equipment. Its main function is to support the mechanical rotating body to reduce the friction coefficient of the mechanical load during the transmission process of the equipment. According to the different friction properties of moving components, bearings can be divided into rolling bearings and sliding bearings.

Introduction

China is one of the earliest countries in the world to invent rolling bearings. In ancient Chinese books, the structure of axle bearings has long been recorded. Judging from archaeological relics and data, China's oldest bearing with the prototype of a modern rolling bearing structure appeared in Xuejiaya Village, Yongji County, Shanxi Province from 221 to 207 BC (Qin Dynasty). After the founding of New China, especially since the 1970s, driven by the strong drive of reform and opening up, the bearing industry has entered a new period of high-quality and rapid development.

At the end of the seventeenth century, C. Wallow of England designed and manufactured ball bearings and installed them on mail trucks for trial use. P. Worth of England obtained the patent for ball bearings. At the end of the 18th century, H.R. Hertz of Germany published a paper on the contact stress of ball bearings. On the basis of Hertz's achievements, R. Strebeck of Germany, A. Pamgren of Sweden and others conducted a large number of experiments and contributed to the development of the design theory and fatigue life calculation of rolling bearings. Subsequently, N.P. Petrov of Russia applied Newton's viscosity law to calculate bearing friction.

O. Reynolds of the United Kingdom conducted a mathematical analysis of Thor's discovery and derived the Reynolds equation, which laid the foundation for hydrodynamic lubrication theory. The early form of linear motion bearings was a row of wooden poles placed under the crowbar. This technology may date back to the construction of the Great Pyramid of Giza, although there is no clear evidence. Modern linear motion bearings use the same operating principle, except that balls are sometimes used instead of rollers. 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 simply 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 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 Guamp; szlig; 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 1895, Henry Timken designed the first tapered roller bearing. Three years later, he obtained the patent and established the Timken Company.

In 1907, Sven Wingquist of the SKF bearing factory designed the earliest modern self-aligning ball bearing.