| With the development of science and technology, modern industrial machineries are becoming more heavy-duty, automated and informationalized, at the same time mechanical transmission have to meet intensively high-power, speed and heavy duty, low vibration, low noise, high efficiency, high strength of gear drive.Because of the high degree of coincidence, smooth transmission, the advantages of carrying capacity, spiral bevel gear, as the basis component for motion transmission of the intersecting axes, is widely used for intersection and cross shaft of various machinery, such as automobiles, engineering machinery, rotorpropelled helicopters, and machine tools.The design process of spiral bevel gear with complex mathematical models and geometric shape involved so many subjective factors, such as design standards, formulas and empirical coefficients, that traditional design method need to check a lot of handbooks, depend on rich design experience, do plenty of similar work in each phrase of the design process from parameter design to paper drawing. So it influences heavily the efficiency and quality of design.This paper engaged in the research of the solution of the series problems in design process of spiral bevel gear including a large amount of work to do, unshared design knowledge, serious dependence on professional knowledge. So knowledge engineering, database management techniques and parametric drawing technology was introduced into the design process. Firstly, the knowledge-based design logic of spiral bevel gear is presented after analyzing carefully the design process and finding out factors which impact the efficiency and quality of design. Then, according to the characteristics of the domain knowledge in the design process, knowledge base of spiral bevel gear composed of case base based on the object-oriented method and rule base based on CLIPS paradigm is founded. And on this basis, a CBR-RBR hybrid reasoning mechanism, consisted of CBR based on database and the characteristic matrix and RBR based on CLIPS, and a parametric drawing model based on CAD secondary development are built. By analyzing and solving the example, the superiority of this system in spiral bevel gear design is validated. Lastly, a CAD design system for spiral bevel gear is developed by Microsoft Visual2005, ObjectARX, CLIPS, etc. tools. The target, the thoughts, the function structure, the database design and the software of system are detailed introduced.This paper reduce the workload, weaken defendence on knowledge of, inheritance and sharing of experience in the design, improve the efficiency and quality of the design. |
