生长型设计中公差进化设计方法研究

为实现生长型设计中尺寸链及形位公差项目的自动生成,在产品结构设计自动化技术基础上,研究生长型设计中公差进化设计的策略与原则。指出生长型设计中紧随结构的自顶向下、不断进化,公差进化设计模型也呈现为一种层次式结构;同时由于功能表面及其名义特征所具有的承载功能及几何信息的特点,可作为公差进化演绎的单元载体;在此基础上建立公差进化设计的基本过程模型。提出产品结构进化设计中,构建基于功能表面的装配网络以及基于名义特征的约束网络的双层装配约束网络的基本方法,给出辅助公差进化设计的公差断言;在此基础上,给出基于双层装配约束网络及公差断言的尺寸链及形位公差进化设计的基本过程。以活塞精镗销孔夹具的公差设计为例,说明所提出的公差进化设计方法在生长型设计中的成功应用。

Tolerance Evolutionary Strategy in Incremental Growth Design

In order to realize the automatic generation of dimension chain and geometric tolerance items in incremental growth design process,the evolutionary tolerance design strategy and its characteristics are studied on the basis of automation technology in the product structure design.The theoretical foundation for the growth design as well as the hierarchical tolerance evolutionary model is given.With the evolution of structure design in top—down style,the tolerance design develops and evolves in the same way,that is,following the evolution of product structure,tolerance grows from the initial accuracy requirements to the final state,during which the basic units in structure growth—functional surfaces and their nominal features are used as the tolerance evolutionary carriers.The basic method for the construction of two-layer correlation network including assembly network based on functional surfaces and constraint network based on nominal features is proposed,and the tolerance assertions to assist tolerance evolutionary design are given.The basic process for evolutionary design of dimensions chain and geometric tolerance based on the two-layer correlation network are presented.The tolerance design of a piston clamp is used as an example to demonstrate the successful application of the proposed tolerance evolutionary strategy in the incremental product growth design process..