密臀av,日韩白嫩少妇露点性爱视频,无码黑人一区,淫语人妻系列

In fact, as early as the Qin and Han Dynasties gear appeared, was made of wood and metal. From its manufacturing materials, we can see that it is used to manufacture all kinds of mechanical products, one of the important parts. In the real life of our common gear types are: from the structural point of view, there are mainly bevel gears, cylindrical gears and non-circular gear, etc., from the tooth point of view, the main application of the most widely used involute gear and cycloidal gear Wait. Gear manufacturing is a specialized process, in order to mass and efficient production of gear, must be used with professional equipment and special tools.

Recently, the application of computers has been expanding and widely used and the continuous development of numerical control technology, along with the development of powder metallurgy products and processing technology, especially the processing of large gears is a leap of development, Out of a lot of new technology. Such as the new CNC milling machine, the new spiral bevel gear CNC machine tools, the use of new tool materials. Which can make large gears faster and more efficient; can be processed more types of gear, the scope of application is more extensive; processing efficiency and accuracy also improved, but also to a certain extent, to protect the environment; work efficiency has improved The In addition, with the development of powder metallurgy products, the application of oil bearing more and more widely.