Study On Conceptual Structure And Tolerance Design Method In Product Reverse Engineering

The theory and technology of tolerance design based on conceptual structure Growing Design is studied based on the National Natural Science Fund project " Study on the design theory and application of simultaneous, synthetical and evolving design of product conceptual structure and tolerance" (Number: 50475129). On this groundwork, the tolerance solving and optimizing in product reverse engineering is realized. The main content is as followed:The research status of Conceptual Design of mechanical products and Computer-aided Design tolerances is comprehensively investigated, the problems existing in the Conceptual Design and Computer-aided Design tolerances are discussed, and the reason of the subject selecting consideration is elaborated.According to the similarity between Product Conceptual Design and Biological Growth, in support of the basic theory of that: Theory of Decomposition and Reconstitution (D&R), Function Surface, Generalized Location Principle, the method of Growing Conceptual Design of product which is based on Location Mode according to Top-Down Design ideas is put forward, and the Growing Design model is created, the system function module by the technology of 00 (Object Oriented) is accomplished. The relationship between function, structure, dimension and tolerance is discussed, the tolerance info model is set up and it is combined with structure design to give a general frame of simultaneous design of tolerance and structure.The automatic generation method of dimension chain is studied, which includes closed loop confirmation, storage and acquisition of its dimension and tolerance information, unit loop confirmation, storage and acquisition of its dimension information and assembly error conformation, storage and acquisition of assembly information. The methods of Tolerance analysis and distribution are expatiated. On the basis of product reverse engineering theory, tolerance solving and optimizing is studied, and tolerance reconstitution is realized in product reverse design process. An example of KD-type code printing machine is given to show the tolerance reverse solving and optimizing, the correctness and validity of the theoretical study and technical implementation are verified, and the further work of conceptual structure and tolerance Growing Design are discussed further.This thesis has important reference and guidance for the conceptual design of mechanical products, especially for the research and development work of Computer-aided tolerance design system.