The transmission shaft is the main force transmission component in the universal transmission device. It is usually used to connect the transmission (or transfer case) with the drive axle, and to connect the differential and drive the wheels when steering the drive axle and disconnecting the drive axle. There are two types of transmission shafts: solid shafts and hollow shafts. In order to reduce the weight of the transmission shaft, save materials and improve the strength and rigidity of the shaft, the transmission shaft is mostly hollow. Generally, the thin steel plate with the thickness of 1.5~3.0mm is adopted, while the super-heavy truck directly adopts seamless steel pipe.