基于功能尺寸最短路径的零件尺寸标注模式的设计

机械零件的尺寸标注模式有多种.尺寸标注模式影响着机械产品的精度和制造成本.为获得零件尺寸合理的标注模式,建立了包含零件尺寸标注所有可能模式的装配尺寸联系路径图;以满足装配体功能尺寸形成路径最短为目标,基于装配尺寸链最短路径原则和最短路径问题的求解,通过2种方法建立了装配体功能尺寸最短路径生成树.功能尺寸最短路径生成树确...     

电磁制动器装配系统的设计与实现

详细介绍了电磁制动器CAD平台的框架结构及装配系统的功能。系统把结构参数、尺寸参数保存在数据库中,通过数据库向用户共享可操作数据,实现零部件模型和数据库之间的双向驱动,解决了特定产品CAD系统中产生的结构参数与产品几何模型尺寸参数间的传递问题,装配系统还具有装配工艺规划与仿真功能。讨论了为实现相应功能装配模型的建立方法,给出了模型库与数据库双向关联与装配工艺规划功能的实现方法。     

基于Inventor的夹具关联设计

基于三维设计软件Inventor 2008,以被加工零件为原始设计基础,利用软件的衍生功能和装配约束自适应特性将设计数据有效关联,使设计跟随原始零件关键尺寸的改变而自动更新,大大提高夹具的设计效率。     

轿车白车身装配过程的一种模型表达方法

提出一种称为“TRAS”模型的轿车白车身装配过程表达模型,通过车身装配树表达工艺过程,通过零件和总成件装配矩阵表达车身结构和装配关系,并通过基准点、定位点、装配点、检测点等及其他要素特征点及其特征矩阵,来描述装配特征和装配尺寸传递关系。该模型为进一步开展定量偏差分析奠定了数据表达基础,可应用于白车身CMM测量数据分析和尺寸偏差诊断。     

装配体的参数化设计研究

通过参数化零件的数据关联分析,并将机械产品的装配模型抽象成两个两件的逐层级联关系,从而对零件模型数据进行装配适应性重构,建立起装配节点上的数据继承、传递和零件驱动关系,实现设计参数和几何模型参数的匹配和连接,从而达到整机产品的参数化设计目的,并以减速箱产品为实例,采用Pro/E系统实现了该装配体的参数化设计.     

浅析门式起重机变型设计

在基因重组的基础上,提出建立装配变形设计的思想。对所装配产品的变型设计原理和变型设计方法进行分析和研究,通过定义装配产品中零件对象的信息模型,建立零件之间的尺寸约束关系模型。以装配门式起重机的部件刚性支腿为研究对象,构建出模型并验证变型过程。     

装配尺寸式的研究

 以装配体内零件要素特征和装配关系信息量最大为目标,对装配体内的各种要素用文字进行描述;提出目标尺寸和相关尺寸概念,以装配基准为线索探索目标尺寸形成的过程,从而建立目标尺寸与相关尺寸之间关系的文字表达式——装配尺寸式,为计算机自动建立装配尺寸关系提供一条新的途径.      

机械装配偏差源及其偏差传递机理研究

分析和研究机械装配偏差源和偏差传递机理用于机械装配精度的预测,机械装备的偏差源按照装尺寸、形位精度、定位精度等影响装配功能的因素可以大致分为三类,即装配位置偏差、几何位偏差和几何形状偏差,建立偏差源的统一表达形式,分析机械装配中零件之间和零件内部的偏差传递机理以及相互作用,明确机械装配中偏差传递的偏差流类型,偏差流可通过偏差向图来进行表达,通过建立机械装配偏差有向图来表达偏差传递和装配功能之间的关系。本文就机械装配精度预测进行简单的说明,着重介绍了机械装配偏差源及其类型,并对机械装配偏差源偏差的传递机理进行了研究。     

J2205胶印机印刷结构虚拟装配平台设计与实现

目的满足胶印机的产品宣传、教育培训等需求。方法以北人J2205胶印机为研究对象,根据印刷机的组成及印刷的实际运转过程,采用Solid Works对胶印机各部分零件进行精确建模并装配成三维机械模型,再利用3ds Max制作零件装配和内部运转的过程动画,最终实现基于VRP的虚拟装配平台。结果完成胶印机虚拟装配平台的制作,该平台能够展现虚拟印刷机印刷部分的整体外观、内部零件、装配过程和内部机械运转动画等。结论将虚拟现实技术与印刷机械相结合,模拟了印刷机械的结构、工作流程及相关特性,可运用于印刷机械的设计研发、产品展示等方面。     

精密微小装配中的传感器与测量技术

装配是高性能精密微小器件或产品制造过程中的关键环节,由于零件及其关键结构的尺寸微小,微小装配必然是基于传感器与测量技术的精密装配。在微小零件装配过程中,需要精确测量待装配零件之间的相对位置和姿态的偏差,控制配合零件之间的接触力或接触状态。首先对用于精密微小装配的传感器技术进行了概述;然后结合精密微小装配中的应用需求,对机器视觉、力觉等主要传感器与测量技术进行了综述,并分析了精密测量与装配控制的技术与方法,旨在对精密装配相关的技术开发、装配设备研制提供参考和借鉴。     

Analysis of dimension data transfer process in product change design

In order to improve product design efficiency, the dimension data transfer process in the process of change design is discussed from two aspects: the propagation of dimension change between the parts and between the key structures inside the part. Firstly, the basic logic structure of product dimension correlation design was analyzed, and the change propagation logic meta-model was established. Then, by analyzing the assembly correlation and dimension correlation among the parts, the correlation path among the parts in assembly and the propagation model of dimension correlation change were established. Taking the change part as the research object, according to the connection and constraint relationship between the internal dimensions of the part, the change propagation path for the internal dimensions of the part was established based on the part modeling process, and the dimension change propagation of the key structures inside the part was completed. Based on the above process, the whole change propagation and data transfer process analysis from the change source to the part and to the specific dimension inside the part were completed. Finally, the validity of the proposed method was verified by an example of a veneer reeling machine. The results show that this method can provide a new idea for the propagation of product dimension change, and provide a theoretical basis for improving product design efficiency.     

工序尺寸换算中假废品的判定及补救措施研究

在工艺基准和设计基准不重合的情况下,在零件加工过程中采用极值法计算工艺尺寸链时经常会出现工序尺寸不合格而最终设计尺寸可能合格的"假废品"现象.为此,以工艺尺寸链极值法计算的特点为基础,对假废品产生的原因进行了分析.为了便于在零件加工过程中判定假废品,通过将工序尺寸作为封闭环尺寸,建立并计算新的尺寸链,得到间接保证设计尺...     

基于FBS的可变功能机械设计变更传播过程及特性分析

介绍了可变功能机械的基本概念及对机械产品进行可变功能设计和进行设计变更传播特性研究的意义.从机械产品概念设计的角度,基于"功能-行为-结构"(FBS)映射模型,分析了机械产品功能之间的关联性,并将功能关联性映射到行为和结构中,在此基础上建立变更设计流程图.通过分析结构体在结构和功能上的约束,得出结构体之间的3种约束关系.在结构体约束关系的基础上,建立结构体关联矩阵,用来描述结构体之间变更传播的可能性.归纳总结了几种典型的传播行为特性,并得出变更传播树模型,为更好选择变更传播路线奠定了理论基础.最后在FBS映射模型基础上对CA6140普通车床进行了数控改造,用传播行为过程图描述了具体零部件之间的变更传播,验证了变更传播分析方法在该映射模型上的可行性.     

基于霍尔三维结构的工业设计模型研究

以霍尔三维结构的思想为启示,论述了在工业设计活动中引入霍尔系统工作方法论的必要性和可行性,结合工业设计学科特点,从时间维、逻辑维、知识维3个维度进行了简要分析。在此基础上,提出了工业设计系统模型的初步构建,旨在为产品设计的实施提供系统化、整体性的理论引导,对于工业设计活动具有方法论层面的指导意义。     

Part dimension deviation control in batch manufacturing process for monitoring error sources

In a batch manufacturing process a cross-correlation exists among dimension deviations of different parts. The modelling and control of these deviations are essential to improve product dimension quality. Traditional dimension deviation statistical control methods have been focused on retrospectively analysing part dimension feature, while based on the spatial relationship between part dimensional features and error sources showed in part dimension error propagation model, this paper presents a method to control part dimension deviation in batch manufacturing that focuses on error sources. At each operation, total part deviation is separated into three components corresponding to three error sources. Therefore, a multivariate exponentially weighted moving average (MEWMA) chart for error sources is proposed to control part dimension deviations with identified error sources attribute to part dimension deviation. Efficiency and reliability of this model were verified by simulation analysis in common error source abnormal patterns, and the model is proved to be effective for detecting small deviations in a batch manufacturing process.     

A multi-phase model for product part change problems

The parts of a product may be changed over the product life cycle for the purpose of enhancing profits, that is to say, product part change has a direct impact on production efficiency and customer satisfaction. The analysis of product part change can provide producers with related components/part suppliers by analysing the product's configuration. Before performing the physical assembly of a specific product, selected part suppliers are connected and have to verify their ability to assemble. This paper proposes an assessment model consisting of three major phases: (1) analysis of the assembly relationship among the parts; (2) preliminary selection of the appropriate parts and their suppliers; and (3) solution selection for supplier association. The proposed model solves the product part change problem for a given related quality level, operation and cost data. The liaison graph, fuzzy theory and value engineering approaches are employed in phases 1 and 2 to analyse the product's configuration and assembly relationships, to deal with production data and to carry out the preliminary analysis. To solve the solution selection model of phase 3, a genetic algorithm based heuristic approach was developed. Finally, the configuration of the stand module of TFT-LCD is used as an example to demonstrate the application and working of the proposed approach. The results of the illustrated example are used to demonstrate its efficiency and effectiveness in solving the part change problem.     

Study on Quality Evaluation Model in Multi-station Assembly Processes

Based on features of dimension variation propagation in multi-station assembly processes, a new quality evaluation model of assembly processes is established. Firstly, the error source of multi-station assembly system is analyzed, the relationship of dimension variation propagation in multi-station assembly processes is studied and the state equation for variation propagation is constructed too. Then, the feature parameters which influence variation propagation and accumulation in multi-station assembly processes are found to evaluate quality characteristic of the assembly system. Through the derivation of equation on dimension variation propagation, station coefficient matrices which are combined and conversed to determine the max eigenvalue are educed. The max eigenvalue is multiplied by the weight coefficient to establish the quality evaluation model in multi-station assembly processes. Furthermore, assembly variation indexes are proposed to judge of the assembly technology process. Finally, through the practical example, the application of the model and assembly variation indexes are presented.     

平面孔系尺寸的建模及其应用研究

针对传统的孔系尺寸计算需要绘制尺寸链图、判断增减环,以及存在过程复杂易出错等问题,提出用工序尺寸的路径图来描述平面孔系的各个孔的加工顺序和加工基准.基于路径图建立全相关的尺寸模型,求解得到具有矢量特征的坐标尺寸,并利用全微分法求解坐标尺寸的公差.避免了现有方法的缺陷,适用于加工中心及数控机床上孔系加工的计算机编程计算.