Material of Gear

The commonly used steels for gear manufacturing are quenched and tempered steel, quenched steel, carburized quenched steel and nitrided steel. The strength of cast steel is slightly lower than that of forged steel, which is often used in larger gears; the mechanical properties of gray cast iron are poor and can be used in open gear transmission with light load; ductile cast iron can partly replace steel to make gears; plastic gears are mostly used in places with light load and low noise requirements, and the gears matched with them are usually steel gears with good thermal conductivity.

In the future, gears will develop in the direction of heavy load, high speed, high precision and high efficiency, and strive for small size, light weight, long life and economic reliability.

The development of gear theory and manufacturing technology will further study the mechanism of gear tooth damage, which is the basis of establishing reliable strength calculation method, the theoretical basis of improving the bearing capacity of gear and prolonging the life of gear, developing new tooth profile represented by circular arc profile, researching new gear material and new manufacturing technology, researching elastic deformation, manufacturing and installation of gear. In order to improve the stability of gear operation and increase the contact area of gear teeth at full load, the profile modification of gear teeth is carried out according to the distribution of error and temperature field, so as to improve the bearing capacity of gear.

Friction, lubrication theory and lubrication technology are basic work in gear research. Studying elastohydrodynamic lubrication theory, popularizing synthetic lubricants and adding extreme pressure additives properly in oil can not only improve the load-carrying capacity of tooth surface, but also improve transmission efficiency.