Abstract: To design the NC axis'repeatability positioning precision of spiral bevel gear milling machine tool reasonably,the active precision design method of spiral bevel gear milling machine tool oriented to the machining precision requirements of parts was proposed.First,the structure and machining principle of NC spiral bevel gear machine tool was analyzed,the tooth surface equation of spiral bevel gear was established with coordinate transformation,and the mapping relationship between tooth surface machining error and NC axis'motion error which named tooth surface machining error model was established by selecting the tooth pitch deviation as the tooth surface error inspecting item.Second,the machining precision requirements of parts was expressed with process capability index Cp and total standard deviation of product characteristic value σw,the expression of NC axis'repeatability positioning precision defined by 4σ principle,and the mapping relationship between tooth surface machining precision and NC axis'repeatability positioning precision which named tooth surface machining precision model was established by combining the standard deviation σ of NC axis'motion error in the tooth surface machining error model.Then,the machining precision requirements of spiral bevel gear was decomposed into NC axis'repeatability positioning precision of spiral bevel gear milling machine tool according to the equal action error distribution principle.The NC axis'repeatability positioning precision of YK2275 spiral bevel gear milling machine tool with six level precision was designed,and the feasibility of the proposed method was verified with the machining precision test of prototype.

Key words: spiral bevel gear, milling machine tool, active precision design, precision distribution, repeatability positioning precision, error model, precision model

摘要： 为合理设计弧齿锥齿轮铣齿机数控运动轴的定位精度,提出一种面向零件加工精度要求的弧齿锥齿轮铣齿机主动精度设计方法。分析了数控弧齿锥齿轮铣齿机的结构和加工原理,通过坐标变换求得弧齿锥齿轮的齿面方程,选取齿距偏差为齿面误差检验项目,建立了机床数控轴运动误差和齿面加工误差之间的映射关系——齿面加工误差模型;用工序能力指数Cp和产品特性值总体标准差σw表示零件的加工精度要求,按4σ原则定义数控运动轴的重复定位精度,并结合齿面加工误差模型中数控轴运动误差的标准差σ,建立了零件加工精度要求和机床数控轴重复定位精度之间的映射关系——齿面加工精度模型;按照等作用误差分配原则,将弧齿锥齿轮的加工精度要求分解为弧齿锥齿轮铣齿机各数控运动轴的重复定位精度。对加工精度要求为6级的YK2275型弧齿锥齿轮铣齿机数控运动轴的重复定位精度进行实例设计,通过样机加工精度测试,验证了所提方法的合理性。

关键词: 弧齿锥齿轮, 铣齿机, 主动精度设计, 精度分配, 重复定位精度, 误差模型, 精度模型