The Conceptual Design Method of Mechanical Products

The conceptual design is the first step of product designing process, it decides the technology economic effect of product radically. The goal of conceptual design is to match the product function with its structure, but the complex relationship between function and structure is a difficult problem in the conceptual design. So a corresponding solution is proposed in the paper. This method is proposed based on the principles as bellows:The product ?function? is a generalized concept. The function attribute not only includes technical attribute described by numerical value, but also includes the attribute described by ?language?, which is called the semantic attribute, such as ?on?-off? and ?protection? of electrical products. Compared with the technical attribute, semantic attribute often describes product function with a bigger granularity, and decides the product structure; However, the size of granularity used for describing product function and structure character of different technical attribute are quite different. So the conceptual design method is proposed in this paper as bellows. Step 1:Firstly separate a product super class into several subclasses according the semantic attribute, which can used to classify each subclasses; and then classify the subclasses´ structure attribute to go on classifying, at last get a tree chart finally. Step2: To contrapose a certain branch node of a ?tree?, it distract all of the technical attributes of their offspring, use the rough theory for attribute reduction,and then take the ?kernel? which is gotten after the attribute reduction as each subclasses´ technical attributes set. Step 3: To seek for product cases of each subclass, set up this subclass´s standard pattern acorroding to all kinds of technical attributes statistical data about those cases. According to the users´ demands about designing, compare the comparability of the ?product to be designed? and interrelated standard pattern, then choose one or several kin- ds of the product type which can almost meet the designing demands. When the designing demand is not completed, the fuzzy attributes of the standard pattern can set to ?the product to be designed?, on which the product conceptual design can be completed.