| On the demand of the more severe competition in the market economy environment, the enterprise has to provide the customer what they need in shorter time. To develop the product CAD system served for individual demand is becoming the choice of many enterprises.The work of this paper is based on the Zhejiang science and technology key project (project NO. 2004C11025) "Automobile EPS(Electric Power Steering) development and key technology research" . It makes deep research into the EPS product, using the UG NX3.0 as the development software and the Visual C++ 6. 0 as the programming environment, makes the research and development of the product CAD system with the UG programming interface UG OPEN/API and some rapid design technologies , such as parameterized, modularized, auto-assembly technology, and finally establish the EPSCAD system. It also carry out the optimization design of the transmission outfit (the worm gear and worm wheel) based on the MATLAB software.On the basis of other people's research result, this paper makes some new trial in the following field, which ends with the expectant result.First, a parameterized design tool with well adaptability is provided. It uses the functions such as the characteristic select dialogue and the sketch select dialogue which is provided by UG, to acquire the model sketch and characteristic in the CAD software, which makes parameters of the sketches and the characteristics to self-display, makes the meaning expression of the non-standard part parameters, and there is no need to do lots of 2D drawing to illustrate the part. It uses the all-through part and all-through expression functions to achieve the auto-exchange of target parts and the transfer of parameters relationships in the assembly. It is more flexible, has more function than the form of just using 2D drawing, and is not limited to exact structure with wide application.Second, provide a simple, fast auto-assembly technology, which involve the concept of assembly interface. It divided the assembly model into three layer: assembly interface model, orientation relationship model and the product assembly relationship, which solve the extract of the assembly information and the expression of the product model. It is simple, not limited to the part structure and without programming. Further more, it applies the parametric technology into auto-assembly and the check of assembly interference check to improve the assembly flexibility.Provide a new method for the modeling of worm gear. Because of the nonlinear quality of the involutes worm axis section, it is difficult to make a accurate model of involutes worm. As defined, the end section of the involutes worm is involutes, herein, this paper thinks up a totally new modeling method, which generates the worm gear model by sweeping the end section along a helix line. In comparison to the known methods of involutes worm modeling, This new method is more accurate and has high stability for parameterized driven. |
