A New Manufacturing Method for Hourglass Worm Gear Hob Based on a Semi⁃automatic CAD  

一种基于半自动CAD的环面蜗轮滚刀制造方法

作　　者：LONG Xinjiani LI Haitao RUI Chengjie YANG Jie ZHANG Xiaodi WEI Wenjun 龙新佳妮;李海涛;芮成杰;杨杰;张筱迪;魏文军(中国农业大学工学院,中国北京100083;中国农业大学现代农装优化设计北京市重点实验室,中国北京100083;北京奎恩特科技有限公司,中国北京100043)

机构地区：[1]College of Engineering,China Agricultural University,Beijing 100083,P.R.China [2]Key Laboratory of Optimal Design of Modern Agricultural Equipment in Beijing,China Agricultural University,Beijing 100083,P.R.China [3]Beijing Kuiente Technology Co.,Ltd.,Beijing 100043,P.R.China

出　　处：《Transactions of Nanjing University of Aeronautics and Astronautics》2020年第6期914-927,共14页南京航空航天大学学报（英文版）

基　　金：supported by The Development of Design and Manufacturing Technology of Double-Enveloping Worm Pair in High-precision with Little Centre Distance(No.69190135);We would like to thank the Professor Workstation of China Agricultural University in Hebei Baoding Laibo Transmission Machinery Manufacturing Co.LTD(No.20200901).

摘　　要：The top relief surfaces of an hourglass worm gear hob are ground manually in the traditional manufacturing process,which cannot ensure the width of the land surfaces of the hob.Moreover,each geometric feature of the hob has been produced through different manufacturing techniques and machine tools,which results in low efficiency.To solve this problem,we propose a semi-automatic computer aided design(CAD)method for hobs.The point clouds of each feature surface of a hob are calculated by combing mathematical equations of the top relief surfaces built by the proposed method with other existing equations of hob surfaces.According to the point clouds,the method can achieve the automatic modeling for the hob in three-dimensional(3D)software by classifying and extracting the parameter information of the feature-hierarchical knowledge of the hob.Based on the generated 3D model,the entire surfaces of the hob can be manufactured on a four-axis computer numerical control(CNC)milling machine through only twice clamping.Verification of the width of the land surface of the hob manufactured by semi-automatic CAD method on a measuring projector proved the precision of the designed width can be ensured.The edge of the contact area on the worm wheel in a meshing experiment is clear and distinct,which means the worm gear drive is meshed well and the hob manufactured by the proposed method has improved machinability.The method simplifies the processing technique,and improves the design efficiency and production accuracy.在传统的制造工艺中,环面蜗轮滚刀刀齿的顶后角面由手工磨削,不能保证滚刀刀齿刃带面的宽度;滚刀的每一个几何特征曲面是通过不同的制造工艺采用不同的机床加工生成,工艺繁琐且制造效率低。为了简化滚刀制造工艺,提高制造效率和刃带面的制造精度,本文提出一种滚刀半自动计算机辅助设计(Computer aided de⁃sign,CAD)方法。首先建立滚刀螺旋面和侧后角面数学模型,在此基础上提出一种滚刀刀齿顶后角面数学模型的建立方法;根据得到的滚刀数学模型计算得到滚刀各特征曲面点云坐标。以点云坐标为基础,通过对滚刀特征层次知识的参数信息进行分类和提取,实现滚刀在三维软件中的自动化建模。根据生成的三维模型,在四轴数控铣床上仅经过两次装夹可加工出完整环面蜗轮滚刀成品。在测量投影仪上对半自动CAD方法制造出的滚刀刀齿刃带面宽度进行测量,证明了刃带设计宽度的精度可以得到保证。在该滚刀滚切出的蜗轮和对应的蜗杆啮合试验中,蜗轮接触区边缘清晰且界限分明,说明了该蜗杆副传动啮合效果良好,用半自动CAD方法制造的滚刀切削性能良好。所提出的半自动CAD方法简化了滚刀制造工艺,提高了滚刀设计效率和制造精度。

关 键 词：hourglass worm gear hob top relief surface feature-hierarchical knowledge SEMI-AUTOMATIC computer aided design(CAD) 

分 类 号：TH132.4[机械工程—机械制造及自动化]