As we all know, bearings (mainly referred to as rolling bearings here) are important and indispensable basic components in contemporary machinery and equipment. Although its rise has a history of more than a hundred years, but because of its relationship with the national economy and people's livelihood, all countries in the world have spared no effort to develop their own bearing industry, and borrowed superb modern science and technology. The development of the world machinery industry and other industries has made outstanding contributions to the progress of human society.

However, the development level of the bearing industry in various countries is uneven, even very disparate. Even if the conditions are met and develop rapidly in countries and regions, due to the consideration of benefits and many other aspects, it is impossible for all varieties to be mass-produced without taking into account the economic benefits. It is a very primitive idea to be self-sufficient in everything. Modern countries use It is also difficult for a great country to do everything without asking for help. Human society is the common world of all mankind. The exchange of ideas, culture and material is the trend of the times. The international trade of bearings came into being and developed continuously by taking advantage of this historical trend. The international trade of bearings is following the development footsteps of the world bearing industry. Like the development process of the world bearing industry, it has also experienced several historical stages that are both interconnected and unique.

The first stage, the initial stage of the world bearing industry, was from the end of the 19th century to the beginning of the 20th century. At that time, although the invention of bearings had been around for a while, the industrial production of bearings had just started from scratch and was quite naive; the main features were: ① The production scale was extremely small, and a large factory only had a dozen sputums going to Yanjiao to play in Japan. The output is only a few sets to hundreds of sets, which belongs to manual workshop production; ② The equipment is simple and the technology is backward, and most of them are produced by experience; ③ The material is mainly carbon steel, the precision is not high, and the price is expensive; ④ There are few varieties and very useful uses. limited. This is the gong time of bearing international trade. At that time, the bearing production technology was only in the hands of a few companies such as the United Kingdom, Germany, Sweden, and the United States, and the technology was kept secret and not communicated with each other; there was no bearing production equipment, so it was difficult to popularize; there were too few bearing varieties, The use is narrow, the market is small, and the price is expensive. No one cares about it except for the assembly of the main engine; the output is very small, and it can not be sold to foreign countries, so that Japan only saw bearing samples for the first time in 1910. The second stage, the growth stage of the good world bearing industry, is about from the end of the First World War to after the Second World War. The two world wars stimulated the development of the military industry, the status of bearings in the military industry has become increasingly prominent, coupled with the rapid development of science and technology, the short-term stability after World War I and the urgent need for arms in World War II, prompted the rapid growth of the world bearing industry, the main features: ① The production scale has expanded rapidly, and the output has increased rapidly. The output of major bearing producing countries has exceeded 35 million sets; ② The production equipment is complete, the technical means are advanced, and the mass production of machine groups is generally adopted; ③ The bearing materials have developed to alloy steel such as chrome steel. Product accuracy is greatly improved; ④ The variety of bearings is increased, which are widely used in many fields such as automobiles, aircraft, tanks and armored vehicles, machine tools, instruments, meters, bicycles, and sewing machines. If the first stage is the monopoly period of the bearing country's sun trade, that is, the breeding stage, then this second stage is the growth stage of the bearing international trade, which is characterized by: due to the expansion of the production scale, the output has far exceeded the domestic needs; ② The variety of bearings has increased and the scope has been expanded. {TodayHot} has thus formed an international bearing market, and the international bearing trade has appeared on the stage and entered its role. During the Second World War, people's understanding and attention to bearings sublimated to the point where the Allied forces attacked the Nazis in Germany. Large-scale cluster bombing, destroying the enemy's morale and economy in one fell swoop, was a typical tactic of World War II. When driving to the German mainland to attack the target, the Allies believed that in order to weaken the enemy's combat effectiveness, they must attack the German submarine factories and bases, aircraft factories, bearing factories,