The Development On Parameterized CAD System Of Three-ring Gear Reducer

The Three-Ring gear reducer, invented by a Chinese engineer in 1985, is a novel type of planetary transmission devices with small tooth differences. It has many advantages over traditional reducers, such as large transmission ratio, high loading capacity, compactness, low cost and wide adaptability. So it has been widely used in many fields. Nowadays 380 types of the new product series have been designed by Tianjin University.This thesis is aimed to apply parametric design to the new product series of three-ring gear reducer. In usual designing of product, the workings on the drawing take almost half of the total time. Furthermore, the parts and the assemblies are similar in mechanical structure and design mode in the serialization development. If we make it one by one, the repeated work will waste a lot.In this situation, a parametric drawing system of three-ring gear reducer has been built. The system developed with LISP and VBA, is based on AutoCAD. The man-machine interfaces are designed with VBA, which has great advantage in interface-making. Assembling drawings and part drawings are completed with LISP automatically. Users input appropriate parameters in the interface, and then it comes with corresponding drawings subsequently. The system realizes parametric drawing and it has avoided fuzzy work availably, enhanced efficiency greatly.