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.
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 has not been 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. "Gu? The original combination "stahlkugelfabrik" or "Fischer Aktien-Gesellschaft" 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.
Industry development
Bearing is an important basic component of various mechanical equipment, and its accuracy, performance, life and reliability play a decisive role in the accuracy, performance, life and reliability of the main engine. In mechanical products, bearings are high-precision products, which not only need the comprehensive support of mathematics, physics and other disciplines, but also need the services of material science, heat treatment technology, precision machining and measurement technology, numerical control technology, effective numerical methods and powerful computer technology, so bearings are also products representing the national scientific and technological strength.
After the international financial crisis broke out in 2008, in response to the financial crisis, the state adopted a proactive fiscal policy, increased infrastructure investment, and stimulated economic development. Benefiting from the development of related industries, the production and sales scale of bearings has expanded rapidly, the profit level has been improved, and the development of the industry has obviously accelerated. According to the data of Forecast of Production and Marketing Demand and Analysis Report of Transformation and Upgrading of Bearing Manufacturing Industry in China issued by Prospective Industry Research Institute, in 2065438, there were a total of enterprises1416 in China bearing manufacturing industry (the annual sales income was more than 20 million yuan), and the total industrial output value was 65438+ sales income19/kl.
In recent years, world-renowned enterprises have entered the bearing market in China and established production bases, such as SKF Group in Sweden, Schaeffler Group in Germany, Timken Company in the United States, NSK Company and NTN Company in Japan. These companies not only operate globally, but also manufacture globally. With the advantages of brand, equipment, technology, capital and production scale, it has launched fierce competition with domestic bearing enterprises. At present, domestic enterprises are mainly engaged in the production of general bearings, and there are few special and high-end bearing manufacturers with immature technology. Therefore, if domestic enterprises want to compete or even surpass foreign advanced bearing brands, they still need to experience a long period of development in technology and other aspects.
During the "Twelfth Five-Year Plan" period, the effects of national macroeconomic policies will continue to show, domestic economic growth will remain strong, the international market will also recover slowly, and the momentum of economic stabilization and recovery will gradually increase. The development of national economy will stimulate the investment in infrastructure, and then promote the development of metallurgy, electric power, construction machinery, building materials, energy and other industries. At the same time, the state has issued ten industrial revitalization plans to provide policy support for the development of automobile, aerospace, machine tools, wind power and other industries, and the demand for bearings in these industries will gradually expand. In addition, the country attaches great importance to the equipment manufacturing industry and the trend of bearing localization is increasingly obvious, and the bearing market in China will usher in a broader development space. At the same time, with the development of bearing main engine industry in China, the product structure of shaft sleeve will change, the proportion of its high-end products in the products will increase, and the sales unit price will also increase. It is estimated that by 20 15, China's bearing output is expected to exceed 28 billion sets, and its main business income is expected to reach 2 10 billion yuan, making it the largest bearing production and sales base in the world.
With the intensification of competition in bearing manufacturing industry, mergers and acquisitions and capital operation between large bearing manufacturing enterprises are becoming more and more frequent. Domestic excellent bearing manufacturing enterprises pay more and more attention to the research of industry market, especially the in-depth study of industry development environment and product buyers. Because of this, a large number of excellent domestic bearing manufacturing brands have risen rapidly and gradually become the leader in the bearing manufacturing industry!