在机械中象螺栓、弹簧、齿轮、轴承、轴、键之类的通用零件数量多,使用面广,它们的设计计算和选用在整个机械设计的过程中占有相当的比重,人们要化不少时间来完成这一工作,而且它们的设计和选用合理与否还直接影响到所设计机器的功能、经济效益和使用寿命。因而长期以来,机械设计和研究人员高度重视通用机械零件的设计理论和方法的研究,逐步形成了比较系统的设计和选用方法。 In machinery such as bolts, springs, gears, bearings, shafts, keys and the like a number of common parts, the use of a wide range of their design calculations and selection of the entire mechanical design process occupies a considerable proportion of people to a lot of Time to complete this work, and their design and selection of a reasonable or not also directly affect the design of the machine’s function, economic efficiency and service life. For a long time, mechanical design and researchers attach great importance to the design of general mechanical parts theory and methods of research, and gradually formed a more systematic design and selection methods.