Transmission of movement and energy transmission, friction wheel drive, key drive, harmonic drive, gear transmission, rope transmission and helical transmission, as well as transmission shafts, couplings, clutches and brakes and other corresponding shafting 0 (part). 3, supporting the role of 0 (parts), such as bearings, boxes and chassis and so on. 4 lubrication system and sealing. 5, Spring and other 0 (part) pieces. As a discipline, mechanical parts start from the overall mechanical design, the principle, structure, characteristics, application, failure form, bearing capacity and design procedure of various basic parts are studied synthetically using the results of each relevant discipline, and the theory, method and criterion of the basic parts of the design are studied, and the theoretical system of this subject is established. Become an important foundation for research and design machinery.