Research On The Virtual Assembly Of Automobile Speed Reducer

Virtual assembly(VM) is a representation of the actual assembly process of product on the computer, it combines virtual reality with assembly modeling techniques effectively. The evaluation on level of component's manufacturability mainly aimed at structure process of product. Manufacturability evaluation on level of manufacture mainly aimed at manufacturing resources , the rationality and manufacturability of components can be ensured through qualitative evaluation. This paper considers the manufacturability evaluation of product during the quantitatively evaluating the assemblability of product. Manufacturability is the premise of assemblability evaluation,and it is unnecessary to discuss the assemblability evaluation of the product without manufacturability. Assemblability evaluation of product could provide some suggestions for the design of product. Based on the manufacturability of product,if the numerical value of assemblability is low,the first step is finding out corresponding component and modifying it according to the evaluation results,then evaluating the manufacturability and assemblability again. Through a series of such process good manufacturability and assemblability could be guaranteed. It is helpful to shorten the time used in designing and developing product, reduce the design cost and reflect market rapidly.This paper establishes models of processing equipment,craft equipment and characteristic using object-oriented modeling methods. First,analyze the structure process of components composing the product,make sure the craft and structure of components are fine. Then evaluate each component's characteristic on the level of manufacturing,search the manufacturing resources by EFCM algorithm. Last, evaluate all of the source comprehensively and obtain the best process scheme.Evaluate assemblability of each component which passed the manufacturability evaluation. This paper establishes the assembly model based on characteristic which provide elementary information of each component and assembly information between each assembled element. Divide the factors which influence assemblability of the product on the level of component and assembly. Give out the qualitative assemblability evaluation by elementary evaluation. The component that can't pass this level of evaluation should be returned to designer for modifying.Evaluate the assemblability of product quantitatively which passed the elementary assemblability evaluation. This paper adopts a method combined fuzzy comprehensive evaluation with analytic hierarchy. In order to use factors effectively,the influencing factors was divided into two levels of component and product. And the level of product is divided into three subclass-level of assembly system,assembly technology and assembly order. First,the first fuzzy comprehensive evaluation of the level of assemble system,assembly technology and assembly order is carried out. Then,the second fuzzy comprehensive evaluation of the level of component and assemble is carried out. Last, do the third comprehensive evaluation to get the assemblability. Contrast the assemblability of products through the result, the optimizing of design scheme can be carried out. When the assemblability evaluation is poor, the factors that influence the assemblability of product could be found by searching step-by-step,feed them back to the designer and repeated the above steps until achieve the designer's requirements.At last, the whole work discussed in this paper is summarized and the research direction of assemblability is prospected.