一、前言已往在旧的齿轮公差标准中,仅规定周节累积误差这一检验项目来控制齿轮在一转范围内平均传动比的变动。但随着机器和仪器制造业的发展,对齿轮在局部范围内平均传动比的变动又提出了新的要求。为此国际标准ISO1328—1975(E)《平行轴渐开线齿轮—ISO精度制》以及苏联标准ΓOCT1643—72《中模数圆柱齿轮传动公差》都增加了一项叫做K个周 I. Introduction In the past, in the old standards for gear tolerance, only the test items for cumulative error in the week were specified to control the average gear ratio change within one revolution of the gear. However, with the development of machinery and equipment manufacturing industry, new requirements have also been put forward on the variation of the average gear ratio of the gear in the local area. To this end the international standard ISO1328-1975 (E) “parallel axis involute gear-ISO precision” and the Soviet Union standard ΓOCT1643-72 “in the module cylindrical gear drive tolerance” have added a called K weeks