The most common arrangement form of the shaft system of the wind turbine is that the large shaft connected to the wind wheel is supported on two separately arranged bearings, and its end is connected to the gear box through a tension sleeve. The bracket of the gear box is installed on the nacelle chassis, and the high-speed shaft of the gear box is connected to the generator with a flexible coupling. This is the so-called "one-line" arrangement. The abnormal load of the wind wheel is usually borne by two large shaft bearings, the gear box is less affected, and the main components are spaced apart, which is convenient for installation and maintenance. Sometimes the generator is reversed to shorten the length of the nacelle. On the large axle box, the input and output shafts of the gear box are on the same side. The large axle box is integrated with the main bracket, which has sufficient support rigidity, and the weight concentration of each part in the engine room is better.