The commonly used steels for making gears are quenched and tempered steel, quenched steel, carburized and quenched steel and nitrided steel. The strength of cast steel is slightly lower than that of forged steel, and it is often used for larger gears; gray cast iron has poor mechanical properties and can be used in light-load open gear transmissions; ductile cast iron can partially replace steel to make gears; plastic gears are often used In places where light load and low noise are required, the paired gears generally use steel gears with good thermal conductivity.
In the future, gears are developing in the direction of heavy load, high speed, high precision and high efficiency, and strive to be small in size, light in weight, long life and economical and reliable.
The development of gear theory and manufacturing technology will further study the mechanism of gear tooth damage, which is the basis for establishing a reliable strength calculation method, and the theoretical basis for improving the load-carrying capacity of gears and extending the life of gears; the development is represented by the arc tooth profile. New tooth profile; research new gear materials and new technology for manufacturing gears; research the elastic deformation of gears, manufacturing and installation errors, and the distribution of temperature When increasing the contact area of the gear teeth, so as to improve the bearing capacity of the gear.
Friction, lubrication theory and lubrication technology are the basic work in the research of gears. Research on the theory of elastohydrodynamic lubrication, popularize the use of synthetic lubricating oil and appropriately add extreme pressure additives to the oil, which can not only improve the bearing capacity of the tooth surface, but also Can also improve transmission efficiency
