The virtual design method ofgear based on knowledge integrates knowledge engineering and parametric design technology, and develops the virtual design system of gearbox gear based on NX platform. The system framework is shown in Figure 1.
The main design process of gearbox gear is as follows:
1) The design parameters, formulas, features, structures, properties and other knowledge of gears are summarized. The knowledge base of gear design is formed by using appropriate knowledge expression method, which is convenient for system call and engineers to check. Parameter and formula knowledge can be imported into NX expression and associated with gear parametric model. Feature and structure knowledge are represented by production method and used for reasoning and judgment. Attribute and design experience knowledge are described by ontology to further improve the sharing and reuse of gear knowledge.
2) Build human-computer system interface. Using NX / open to make user menu and user input dialog box, it is convenient for designers to input design parameters and realize seamless connection between gear virtual design system and modeling software NX.
3) Establish gear model library. Parametric modeling of different gear features is carried out, and associated with gear parameters, formulas and rules to form a general gear model library. It makes the gear model have the ability to evolve multiple structures without conflict, which can make up for the shortcomings of the traditional simple parametric design system.
4) Create parametric gears. In the environment of visual studio 2013, a program is written to associate user design parameters with gear model, establish rules and make intelligent selection of gear structure.
The knowledge-based gearbox virtual design system can intelligently and rapidly design the gears, reduce the repetitive work of designers such as consulting design manual and modeling repeatedly, improve the efficiency of model construction in gearbox virtual simulation, and shorten the research and development cycle of gearbox.