Bearing is an important part of modern 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 elements, bearings can be divided into rolling bearings and sliding bearings. Among them, rolling bearing has been standardized and serialized, but compared with sliding bearing, its radial size, vibration and noise are larger and its price is higher.
Rolling bearings are generally composed of outer ring, inner ring, rolling body and cage. According to the shape of rolling elements, rolling bearings are divided into two categories: ball bearings and roller bearings.
Basic information
Bearing ("bearing", Japanese call it "bearing") is a component to fix and reduce the friction coefficient of load during mechanical transmission. It can also be said that when other parts on the shaft move relatively, it is used to reduce the friction coefficient in the process of power transmission and keep the center position of the shaft fixed. Bearing is an important part of modern mechanical equipment. Its main function is to support the mechanical rotating body, so as to reduce the friction coefficient of mechanical load in the transmission process of equipment. According to the different friction properties of moving elements, bearings can be divided into rolling bearings and sliding bearings.
brief introduction
China is one of the countries that invented rolling bearings earlier in the world. In China's ancient books, the structure of axle bearings has been recorded for a long time. According to archaeological relics and materials, the earliest bearing with modern rolling bearing structure in China appeared in Xuejiaya Village, Yongji County, Shanxi Province from 2265438 BC to 207 BC. After the founding of New China, especially since 1970s, bearing industry has entered a brand-new high-quality and rapid development period under the strong impetus of reform and opening up.
/kloc-At the end of 0/7th century, C. Wallow in Britain designed and manufactured ball bearings, and put them on a mail truck for trial use. P. Worth in Britain obtained a patent for ball bearings. /kloc-at the end of the 8th century, H.R. Hertz of Germany published a paper on contact stress of ball bearings. On the basis of Hertz's achievements, R. Striebeck of Germany and A. Parmgren of Sweden carried out a lot of experiments, which contributed to the development of 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 England made a mathematical analysis of Thor's discovery, and deduced Reynolds equation, which laid the foundation of hydrodynamic lubrication theory. In the early form of linear motion bearing, a row of wooden sticks were placed under the pry plate. This technology may be traced back to the construction in great pyramid of giza, although there is no clear evidence. Modern linear motion bearings use the same working principle, but sometimes balls are used instead of rollers. The earliest sliding bearings and rolling bearings were made of wood. Ceramics, sapphires or glass are also used, and steel, copper, other metals and plastics (such as nylon, phenolic plastics, Teflon and UHMWPE) are widely used.
From heavy-duty wheel shafts and machine tool spindles to precision clock parts, rotary bearings are needed in many occasions. The simplest rotary bearing is a sleeve bearing, which is just a bushing sandwiched between the wheel and the axle. This design was later replaced by rolling bearings, that is, many cylindrical rollers were used instead of the original bushings, and each roller was like an independent wheel. The earliest practical rolling bearing with cage was invented by watchmaker john harrison in 1760 for making H3 chronograph.
An early example of ball bearing was found on an ancient Roman ship found in Lake Nano, Italy. This wooden ball bearing is used to support the rotating table top. The ship was built in 40 BC. It is said that Leonardo da Vinci once described a ball bearing with a ratio of 1500. Among all kinds of immature factors of ball bearings, it is very important that the balls will collide and produce extra friction. But putting the ball in a small cage can prevent this phenomenon.
/kloc-in the 0/7th century, Galileo first described the "fixed ball" or "cage ball" ball bearing. But after a long time, it was not realized to install bearings on the machine. The first patent on fairway was obtained by Philip Vaughan of Carmarthen in 1794. ?
In 1883, Friedrich Fisher put forward the idea of using a suitable production machine to grind steel balls with the same size and accurate roundness. This laid the foundation for establishing an independent bearing industry. The original combination "stahlkugelfabrik" or "Fischer Aktien-Gesellschaft" of "Financial Auto Car Care & ampszlig" later became a trademark, registered on July 29th, 1905.
1962, the trademark FAG was modified and still used today, and it became an inseparable part of the company in 1979.
1895, Henry Timken designed the first tapered roller bearing. Three years later, he obtained a patent and established Timken Company.
1907, Sven Wingqvist of SKF Bearing Factory designed the earliest modern self-aligning ball bearing.