Single screw(double screws) extruder gearbox is specially designed for plastic screw extruder design of high precision hard tooth surface with thrust of driving part. Product design adopted the JB/T8853-2001 under the technical specifications. Its characteristic is gear and shaft parts adopt high strength alloy steel. Gear by carburizing, quenching and grinding process. Gear accuracy is 6 according to GB10095-88 Tooth surface hardness HRC54-62. In the hollow output shaft front-end configuration has super specifications of the thrust bearing, screw work under axial force. Bearing and oil seal and other major standard parts are using domestic high quality products, can also according to user needs, equipped with imported products. The machine has small volume, high bearing capacity, stable transmission, low noise, high efficiency, etc. Product performance has reached the international advanced level.