Research Of Bicycle Rear Triangle Frame CAD System Based On Knowledge And Parameterized Methods

Bicycle frame design is the most important and crucial process in bicycle development. As the structure of bicycle frame seems to be simple, it has a low threshold to enter the domestic bicycle design and manufacture business. The domestic manufacturers attach much more importance to earn profit from the manufacturing and managing processes than emphasizing on the quality of the product, and there is a big gap between the domestic and international levels of bicycle design. As a tool to improve the efficiency and quality of frame design, the bicycle frame CAD system starts to draw more and more attention.The domestic frame CAD systems are generally developed on the basis of 2D design technology. There are some disadvantages in these systems. For example, the dimensions are not parameterized, users have to start over again if one step is wrong, it is difficult to involve frame design knowledge, and design effect can not be displayed in real-time. This thesis studies on the above problems, by using parametric technology on 3D design platform, and the solutions to the above-mentioned problems is provided.Based on the characteristics of parameterized design and key technologies of knowledge based engineering, and specially according to the characteristics of the construction, figure, assembly-parameter of bicycle frame design, the article has achieved repeated using of experiential parameter and knowledge by adopting methods such as automatic reading experiential datasheet, computing parameter by making use of program, manual data-input or modifying and so on. Based on analyzing the characteristics of Rear End design and the associated characteristics with Chain Stay and Seat Stay, different design methods are analyzed in detail, and rapidly assembling of Rear End, Chain Stay and Seat Stay is achieved by using the method of combining top-down-assembly with down-top-assembly method. Based on analyzing special technologies and UDF characteristics, the repeated using of different sectional shapes by using UDF technology on the tube section design is also achieved, and this will greatly shorten the time spent on fixing the dimensions and orientations on sketches.In this study, the author worked together with the group members and developed the bicycle frame CAD system, and was mainly in charge of the Rear frame design. By using the new CAD system, the assembly 2D drawing, which formerly needed 2 days to finish, can now be completed smoothly in only 2 hours.