基于Pro_Engineer的组件参数化建模

文章编号:1004-2539(2006)03-0040-02基于Pro/Engineer的组件参数化建模(武汉理工大学,　湖北武汉　430070)　王三武　刘　坤　马书恒摘要　介绍了Pro/Engineer环境下,通过组件与元件间的共享参数关联,实现组件自上而下的参数化建模方法。

采用这种方法,有利于产品修改和系列化设计,提高设计效率。

关键词　Pro/E　组件参数化建模 引言Pro/Engineer是美国PT C推出的C AD/C AM软件,该软件具有三维实体设计、装配、加工、分析、运动仿真和工程图自动生成等功能,在国内使用广泛。

Pro/E 在组件的设计上,有一种“自顶向下的设计概念”,为组件参数化建模提供了一个方法。

此前,关于元件的参数化研究已趋成熟,本文将就组件的参数化建模进行探讨。

1　组件参数化建模的特点与元件参数化设计相比,组件的参数化设计除要考虑抽象出相同的尺寸外形参数外,还需考虑元件间的配合关系。

Pro/E软件自带的布局模块,可以绘制产品的几何轮廓,建立参数和数学关系式,关联并控制组件内零件模型的几何参数,可以建立全局特征,实现自动装配,为组件参数化设计提供了一种方法。

2　组件参数化建模的步骤2.1　提取共享参数共享参数即组件中涉及或影响元件位置关系、配合关系及与其他组件有相对运动的参数或基准(包括共同的定位中心线、基准面、坐标系等几何参数)基本都已确定,在具体的Pro/E布局模块中要做的是按参数的主次轻重分类,选择重要的参数来控制各元件间装配位置及配合,保证机构机械性能。

如图1,选择3个齿轮的定位尺寸,轴左端面,中心线作共享参数。

2.2　创建布局文件布局模块所做的工作是进行产品的初步规划,在这块工作的重点不是绘制准确的图形,重要的是建立针对上一步的共享参数建立合理的全局定位特征,将参数在图形上表达清晰,在有关联性的参数间建立关系式。

这部分的工作琐碎,可在后续步骤中交替进行。

建立的一般原则应是先整体后细节,先简单后复杂。

如图1定义了3个齿轮的定位参数L1,L2,L3和中心轴AX1,注意选择重要的参数定义,如果开始就企图在布局中建立整个组件的参数,工作量大而且也易出错。

图1　齿轮轴布局图2.3　创建装配图文档根据我们的尝试,创建装配图应遵循下面步骤:①建立全局基准特征,如:上图布局中的基准轴;②声明组件或元件与布局的链接。

布局中创建的参数将与组件的参数进行链接,使组件的参数与布局的参数产生相依的关系,之后只要更改布局的参数值就可以直接控制组件的参数值,从而实现自上而下的参数化。

③装配已经参数化的元件,如齿轮、轴承等;④创建新的元件,这类元件因其他结构而变,一般很难事先就参数化设计,如:轴,套筒等;需要注意的是,一个装配体需要很多页的布局图来清楚的展示定位关系及元件的几何形状。

图1布局图的实体模型图如图2所示。

图2　齿轮轴三维模型2.4　关联元件参数关联元件参数的过程就是组件参数化的过程。

这个过程中的工作需计算尺寸链,定义尺寸之间的关系04 机械传动 2006年式,将组件中各元件的尺寸都用布局中给定参数表示。

过程繁琐但结果将振奋人心,完成后只需修改布局中的相关参数就可实现整个组件的改变,避免了传统设计方法改动繁琐易错的问题,在系列化的产品设计中,这个设计方法可大大地提高设计效率。

2.5　创建参数对话框利用Pro/E 提供的Program 功能,可设计对话框,使修改目标明确,使设计的组件更有弹性。

Program 利用EXEC UTE 的功能为元件与组件建立一座沟通的桥梁。

具体思路:先在组件和元件的Program 文件的I N 2PUT 区建立参数,再在组件里EXEC UTE 区建立关联关系式,在元件RE LATI ON 区建立元件模型中的参数关系式。

以图1为例建立轴径、齿轮和轴承孔径的联系,在组件中输入如下语句:I NPUTDI A1NUM BER //DI A1为参数名”输入轴粗端直径”DI A2NUM BER //number 为参数类型”输入轴细端直径”E ND I NPUTEXEC UTE PART GEAR-60图3　程序执行时的提示菜单GE AR-DI A =DI A1E ND EXEC UTE EXEC UTE PART AXIS DI A1=DI A1DI A2=DI A2E ND EXEC UTE………………EXEC UTE ASSE M BLY 61802BE AR-I N-DI A =DI A1E ND EXEC UTE上述语句中,“part ,assembly ”表示欲控制的下一级元件类型。

其后为文件的名称。

在参数关系式中左边参数是下一级文件Program 中定义的参数名称,右边的为组件中定义的参数名称。

如需修改设计,再生零件后选择参数输入新值即可完成。

将轴径修改后,组件图如图4所示。

3　组件参数化设计在具体产品开发中的应用 设计任务要求开发出若干系列适用不同尺寸要求的管道扫查装置,其结构类似,采用了这种参数化方法,缩短了设计周期。

其中行走小车部分绘制布局图如图5所示。

总成图见图6。

图4　更改参数后齿轮轴模型图5　实例驱动小车布局图图6　驱动小车设计完成图4　结论利用Pro/E 软件的全参数化功能设计复杂的机械装配体,通过参数关联构成基于装配体的参数化建模,将有利于设计的后续修改和系列化设计,提高设计效率,其建立的参数也能被装配体的结构分析及优化所利用。

但笔者并不提倡将每一个细节都建立参数进行控制,那将使工作更加繁琐。

事实上,只需将重要的参数关联起来,在工作中注意将布局和Program 方法结合使用,一般前者使用在装配位置参数控制上,后者使用在装配元件几何形状参数的控制上。

设计人员在决定使用自上而下的参数化设计时,必须有清晰的总体思路,再通过上述方法,方可提高效率,事半功倍。

参考文献1　张沛颀,裴建昌等.Pro/E NGINEER 野火版进阶设计.北京:人民邮电出版社,20042　王三武,景仁坤,余旭阳.基于Pro/Engineer 齿轮自动化造型.机械传动,2004(5)收稿日期:20050523作者简介:王三武(1959-),男,湖北浠水人,副教授14第30卷　第3期 基于Pro/Engineer 的组件参数化建模 Abstract　Many questions in natural science and engineering are trans2formed into nonlinear equations to be found,Newton iterative method isan im portant technique to one dimensional and multidimensional vari2ables and iterative process exhibits sensitive dependence on initial guesspoint.F or the first time,a new method to find all s olutions based on u2tilizing tw o dimension chaos mapping based on logistic m odel with onepower coupling term to obtain locate initial points to find all s olutions ofthe nonlinear questions is proposed.The numerical exam ples in linkageaccurate points m ovement synthesis show that the method is effective.K ey w ords:　Chaos　T w o dimension mapping　Logistic m odel　Linkage mechanism　N onlinear equationsK inem atics Analysis of a Three-dimension T ranslational P arallelR obot Zhang Y inglong(23)…………………………………………Abstract　A parallel robot of(P//R//R)//(C//R//R)(P//R//R)is introduced.The mechanical principle and the position of the par2allel robot are discussed firstly by the screw theory,then freedom of theparallel robot is g ot.The conclusion of freedom are certificated by usingthe s oftware of ADAMS.At last,the s olutions are developed for the in2verse and forward kinematics including position,velocity and accelera2tion analysis.K ey w ords:　Parallel robot　Screw theory　K inematics analysisStudy on p arameterized model and virtu al assembly of involute he2lical gearLuo Shanming,Wang Jian,Wu X iaoling,Chen Lifeng,Huang Jinglong(26)…………………………………………………………Abstract　Based on Pro/Engineer,the method of3D parameterizedm odel of inv olute helical gear with m odification is studied and the prin2ciple of virtual assembly with meshing backlash is introduced.Inputgear width,helical angle and five basic parameters of inv olute helicalgear,the accurate3D s olid m odel of inv olute gear w ould be attainedautomatically.I t is significant to im prove the accuracy of design,as2sembly and manu facturing of the inv olute helical gear.K ey w ords:　Helical gear　Parametric m odel　Virtual assembly　Meshing backlashA Simulating Analysis Model for SpiralB evel G ear Meshing inAerostat R educer Li Y uan,Y uan Jiehong,Li Junwu(29)…………Abstract　By using the large finite element method s oftware MSC.Marc,A3-D nonlinear contact analysis m odel for a pair of spiral bev2el gear with several meshing teeth pairs is established.Based on them odel,A quasi-static meshing simulation in the case of definite torqueand rotary speed are carried out in a meshing period.The numerical re2sults which indicating the variety of the contact status,the contactstress,the bending stress in the location of teeth root and the torque androtary speed of gear pair vs.the different meshing position are present2ed,and show a very g ood agreement with the meshing rules in reality,and simultaneously,the rationality of the m odel is be verified.K ey w ords:　MSC.Marc　Finite element method　S piral bevel gear　C ontact　Quasi-static meshingK ey T echnology of Free-form Surface R everse E ngineeringXu Y ingxun,Ding Hao,Zhu Shigeng(32)………………………Abstract　The key technology and research way was presented of the reverse engineering,The data processing and C AD m odel was intro2 duced.The C AD m odel and re-design of the real part are illustrated. K ey w ords:　Reverse engineering　Free-form sur face　P oint cloud M odel reconstructionP arameterization of Cycloid G ear in FA P lanetary T ransmission of Cycloid al N eedle-wheel Zhang D ongsheng,G uan T ianmin(35)……Abstract　In order to get accurate and automatical cycloid gear m odel rapidly,which is very com plex entity in FA planetary transmission of cycloidal needle-wheel,m odle parameterization of cycloid gear is fin2 ished,by setting up mathematics m odel to describe the gear profile of cycloid gear,and adopting the advanced programming language that Pro/E offers.Only by inputting already known design parameters,de2 signer may get three-dimensional entity m odel what he needs very ac2 curately and rapidly.K ey w ords:　FA planetary transmission of cycloidal needle-wheel　Cycloid gear　Parameterization　Automatic characteristic m odeling The Three-dimension P arametric Solid Model of Double Arc G ear Liu K unmin,Wang T ie(37)…………………………………Abstract　A method of setting up accurate three-dimension paramet2 ric s olid m odel of double arc gear by using the parametric function of Pro/Engineer is introduced.This method can im prove the efficiency and precision of design.I t provides a foundation for intensity analysis,smu2 lation and virtual assembly of s olid m odel of double arc gear.K ey w ords:　D ouble arc gear　Parametric　S olid m odel　Pro/Engi2 neerP arametric Assembly Modeling B ased on Pro/E ngineerWang Sanwu,Liu K un,Ma Shuheng(40)………………………………Abstract　A method of m odeling parametric assembly under Pro/Engi2 neer is intraduced,by connecting the sharing parameters between the assembly and the com ing the method,it is in fav or of the m odification and serialized design of a product,thereby of developing the design efficiency.K ey w ords:　Pro/E　Parametric assembly m odeling3D P arametric CAD of Cylindrical C amsHuang K ai,Li Lei(42)………………………………………………………………Abstract　The3D parametric m odeling of cylindrical cams is realized under Pro/E environment using its program function.As a result,the efficiency,accuracy,and extent of intelligence of design and manu fac2 ture for this type of cams can be im proved significantly.K ey w ords:　3D　ParametricC AD　Cylindrical cams　Pro/E Method of Selecting the Modification Coefficient of the G ear for the F luid Coupling G ear PumpZhao Wenshu,Zhang Xudong,S i Jian,Luo Y uhong(44)…………………………………………2 英文摘要 。