Research On Function Structure And Assembly Redesign Of Adaptable-function Mechanical Products

The adaptable-function mechanical system is a kind of mechanical system which can accomplish different functions by changing the system components or adjusting the connection between the components.Compared with the traditional single-function mechanical products,this kind of products have the characteristics of compact structure and multiple functions.However,with the continuous development of science and technology and the constant updating of the market demand,such products might also need upgrading in function and performance,or due to the new market demand.For example,the functional structures of the product(i.e.the structural components delivering the adaptable functions)may not cater for customer requirements any longer,and the assembly and disassembly of product structure(necessary for switching between different functions)may not be as convenient asexpected.Therefore,it is of significance to conduct research on redesign of the adaptable-function mechanical products,which has not been done comprehensively as yet.To address this problem,this thesis will carry out the following aspects of research:First of all,the functional structure of the adaptable-function mechanical products is analyzed and studied,and the sub-functions of the products are obtained through the decomposition of the function tree model;then the use degree and priority of the functions are defined,and the subfunctions obtained are further investigated by the questionnaire to obtain the feedback of the target users on their usage;finally,the questionnaire data is processed to obtain the functions suitable for the target users,making it ready for the further study of redesign.Secondly,the selection of suitable sub-functions and combination of the sub-functions,together with their corresponding functional structures,are studied.The classification of functions and the expected new function are obtained through questionnaire survey and data processing,followed by analysis of the behavioral processes and the behavioral structure of the product in delivering each of the functions,with which the functions are combined.And,the interface design of the components is also carried out,so that the product structure is eventually formulated.Finally,the feasibility of these methods is verified by the case study of multi-functional combination pliers.Thirdly,the technical and economic analysis of the new parts introduced in the redesign process is carried out to ensure that the introduction of new parts is feasible;then the replacement parts are redesigned to the design requirement,so as to ensure the implementation of the overall function of the product.Based on these results,the cost of the product is evaluated to assist the designer in making design decision.Finally,five assembly redesign rules and the corresponding assembly redesign steps for the adaptable-function products are proposed to meet the requirement of design for assembly used for switching between functions.The feasibility of the proposals is verified by the redesign of a multifunction rescue escape chair.