Planetary reducer internal gear using 20CrMnTi carburizing and quenching and grinding has the advantages of small volume, light weight, high carrying capacity, long service life, stable running, low noise, large output torque, the characteristics of high efficiency, large speed ratio, safety performance. Both the characteristics of power flow, the use of the teeth. Is a kind of extensive new gear reducer general. The maximum output power of up to 104kW. Suitable for lifting and transporting, engineering machinery, metallurgy, mining, petrochemical, construction machinery, textile and light industry, medical equipment, instruments, vehicles, ships, weapons, aerospace and other industrial sectors planetary series of new varieties of WGN fixed axis gear reducer, gear reducer, WN composite elastic load balancing less differential gear reducer device