975x50x1MM Green PVC Conveyor Flat Belt Conveyor Climbing

Bearing is an important part of 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.
Historical development
The early form of linear motion bearing is to place a row of wooden poles under a row of skids. Modern linear motion bearings use the same working principle, but sometimes use balls instead of rollers. The simplest rotary bearing is the sleeve bearing, which is just a bushing clamped between the wheel and the axle. This design was subsequently replaced by rolling bearings, in which many cylindrical rollers were used to replace the bushings, and each roller was like a separate wheel.
An early example of a ball bearing was found on an ancient Roman ship built in 40 BC, which was found in the Italian Lake Nami: a wooden ball bearing was used to support a rotating table. It is said that Leonardo da Vinci once described a ball bearing around 1500. Among various immature factors of ball bearings, one of the most important is that the balls will collide with each other, causing additional friction. But you can prevent this phenomenon by putting the ball into small cages. In the 17th century, Galileo first described the ball bearing of "cage ball". At the end of the 17th century, C. Warlow of England designed and manufactured ball bearings, which were installed on mail cars for trial use, and P Worth obtained a patent for ball bearings. The earliest practical rolling bearing with cage was invented by watchmaker John Harrison in 1760 for making H3 hour meter. At the end of the 18th century, H.R. Hertz of Germany published a paper on contact stress of ball bearings. On the basis of Hertz's achievements, Germany's R. Stribeck and Sweden's A Pamgren et al. conducted a large number of tests, which contributed to the development of the design theory and fatigue life calculation of rolling bearings. Later, Russian N.P. Petrov applied Newton's viscosity law to calculate bearing friction. The first patent on the raceway was obtained by Philip Vaughn of Camasson in 1794.
In 1883, Friedrich Fisher put forward the idea of using appropriate production machines to grind steel balls with the same size and accurate roundness, which laid the foundation for the bearing industry. Britain's O Reynolds made a mathematical analysis of Torr's discovery and derived Reynolds equation, which laid the foundation of hydrodynamic lubrication theory.
Industry overview
According to the data of the National Bureau of Statistics, in 2011, there were 1416 enterprises in China's bearing manufacturing industry (with an annual sales revenue of more than 20 million yuan), which achieved a total industrial output value of 193.211 billion yuan, a year-on-year increase of 27.59%; The sales revenue was 191.097 billion yuan, with a year-on-year growth of 30.30%; The total profit was 12.523 billion yuan, an increase of 26.54% over the previous year. It is estimated that by 2015, the output of bearings in China is expected to exceed 28 billion sets, and the main business income is expected to reach 210 billion yuan, becoming the world's largest bearing production and sales base.
At present, China's bearing industry is mainly faced with three outstanding problems: low concentration of production, low R&D and innovation ability, and low manufacturing technology level.
First, the industrial production concentration is low. Among the world's bearing sales of about 30 billion dollars, the world's eight largest multinational companies account for 75%~80%. Germany's two major companies account for 90% of the total, Japan's five companies account for 90% of the total, and the United States one company accounts for 56% of the total. However, the sales of the 10 largest bearing enterprises in China, such as bearing shaft, accounted for only 24.7% of the total industry, and the production concentration of the top 30 enterprises was only 37.4%.
Second, the R&D and innovation capabilities are low. Weak basic theoretical research in the whole industry, weak participation in the formulation of international standards, few technologies and few patented products.
At present, our design and manufacturing technology is basically imitated, and our product development ability is low, which is reflected in: although the matching rate of domestic main engines has reached 80%, the matching and maintenance bearings of important main engines such as high-speed railway passenger cars, medium and high-end cars, computers, air conditioners, and high-level rolling mills are basically imported.
Third, the level of manufacturing technology is low. The manufacturing process and equipment technology of the bearing industry in China are developing slowly, the CNC rate of turning is low, and the level of grinding automation is low. There are only more than 200 automatic production lines in China. Advanced heat treatment processes and equipment that are critical to bearing life and reliability, such as controlled atmosphere protective heating, double refining, bainite quenching, have low coverage, and many technical problems have not been solved. The research and development of new steel grades of bearing steel, the improvement of steel quality, and the research and development of lubrication, cooling, cleaning, abrasive tools and other related technologies cannot meet the requirements of improving the level and quality of bearing products. As a result, the process capability index is low, the consistency is poor, the product processing size dispersion is large, and the internal quality of the product is unstable, which affects the precision, performance, life and reliability of the bearing.