Abstract: To meet the requirements of constructing 3D machining process models for box parts of diesel engines rapidly,a method for removal volume of crankshaft holes was proposed.The characteristics of crankshaft holes of diesel engines' box parts were analyzed,and the crankshaft holes were divided into Unit-hole Features (UHF).Judgment algorithm for non-closed internal cylindrical surface in UHF was developed by taking UHF as the research object.The non-closed internal cylindrical surface was screened in the whole model in axial and radial based on geometric reasoning method.According to the arrangement of UHF's adjacent faces,UHF was divided into outer-loop feature and inner-loop feature,and the recognition algorithm process for them was proposed.According to the type of UHF,the removal volume of UHF was constructed.To verify the effectiveness of the proposed method,the modular for constructing removal volume of crankshaft holes was developed based on NX.

Key words: crankshaft holes, removal volume, face group, unit-hole feature

摘要： 为满足柴油机箱体零件三维机加工艺模型快速创建的要求,提出了构建曲轴孔系去除体的算法流程。首先,分析柴油机箱体曲轴孔系特征,将曲轴孔系按照面的邻接关系分解为单位孔特征,以单位孔特征为研究对象,提出单位孔特征内非封闭内圆柱面的判断算法;然后基于几何推理的方法,利用初选的非封闭内圆柱面的轴向和径向两个特性在全模型上筛选;其次,依据单位孔特征相邻面分布情况,将单位孔特征分为外环孔特征和内环孔特征,并创建各自的识别算法;最后,基于单位孔特征的类型构建材料去除体积。基于NX开发的曲轴孔系去除体构建功能模块验证了该方法的有效性。

关键词: 曲轴孔系, 去除体, 面组, 单位孔特征