The gear box shall bear the force from the wind wheel and the reaction force generated during gear transmission, and shall have sufficient rigidity to bear the force and torque, prevent deformation and ensure the transmission quality. The design of gear box shall be carried out according to the layout arrangement, processing and assembly conditions, easy inspection and maintenance of wind turbine power transmission. With the continuous and rapid development of the gearbox industry, more and more industries and different enterprises have applied the gearbox, and more and more enterprises have developed and expanded in the gearbox industry.

　　Gear box is an important component widely used in mechanical transmission. When a pair of gears mesh, due to the inevitable errors of tooth pitch and tooth shape, meshing impact will occur during operation, resulting in noise corresponding to gear meshing frequency, and friction noise between tooth surfaces due to relative sliding. Since gear is the basic part of gearbox transmission, reducing gear noise is very necessary to control gearbox noise. Generally speaking, the noise of gear system is mainly caused by the following aspects:

　　1. Gear design. Improper parameter selection, too small coincidence, improper or no tooth profile modification, unreasonable gearbox structure, etc. In gear processing, the pitch error and tooth profile error are too large, the tooth side clearance is too large, and the surface roughness is too large.

　　2. Gear train and gearbox. Assembly eccentricity, low contact accuracy, poor parallelism of shaft, insufficient stiffness of shaft, bearing and support, low rotation accuracy and improper clearance of bearing, etc.

　　3. Input torque in other aspects. Fluctuation of load torque, torsional vibration of shafting, balance of motor and other transmission pairs, etc.