基于UG的EXP文件的直齿圆柱齿轮的参数化设计

根据数据加工的精确性要求，UG提供的表达式文件功能就成了精确建模的首选。利用该功能，实现了渐开线齿轮的轮廓线的精确建模。为满足参数化设计要求，将表达式文件的操作简化，基于VC＋＋6．0平台编制了程序，将渐开线与齿根圆、齿顸圆的交点计算过程隐藏在后台，通过输入渐开线齿轮的模数、齿数、压力角、齿根距和齿顶距等5个参数，即可生成UG所用的表达式文件，一次性将半个齿廓曲线生成而无需任何额外操作。整个程序的参数输入非常简单，对UG的操作也非常简练，满足参数化设计需求。

Parametric Design of Spur Cylindrical Gear based on Exp File of UG

According to the accuracy requirements of CNC machining, the function of Exp file in UG is the first choice to accurate modeling. By using this function, the accurate modeling of contour on involute gear is realized. In order to meet the demands of parametric design, the operation of the expression files is simplified,meanwhile a program is developed based on the platform of VC＋＋6.0. The calculation of intersection points that intersects the involute with dedendum and addendum circle are hidden as black box. Then an exp file for UG is generated by inputting to five parameters., modulus,tooth number, pressure angle,dedendum and addendum distance. And a half of involute profile can be generated in one step without any additional operation. In this design,the input of parametric is very simple,and the operation of UG is concise, furthermore the design can meet the requirements of the parametric design.