The structural design of the shaft is an important step in the design of the shaft to determine the proper shape of the shaft and the overall structural dimensions. It consists of the type, size and position of the part mounted on the shaft, the way the part is fixed, the nature, direction, size and distribution of the load, the type and size of the bearing, the blank of the shaft, the manufacturing and assembly process, the installation and transport, the shaft The deformation and other factors are related. The designer can design according to the specific requirements of the shaft. If necessary, several schemes can be compared to select the design scheme. The following are the general shaft structure design principles: 1. Save materials, reduce weight, try to use equal-strength dimensions or Large section coefficient cross-sectional shape; 2, easy to accurately position, stabilize, assemble, disassemble and adjust the parts on the shaft; 3. Use various structural measures to reduce stress concentration and increase strength; 4. Easy to manufacture and ensure accuracy.