GEOMETRIC AND SOLID MODELING FOR GEAR CAD/CAM

摘要

This paper deals with geometric and solid modeling of involute gears. First, necessity of computer aided design and manufacturing (CAD/CAM) of gears is introduced. Next, parametric equation of the involute curve and its approximate expression by linear or circular segments within a specified tolerance are described. Then, solid modeling processes of a spur gear, a helical gear, a bevel gear and a special chamfer on gear teeth are completed by using general-purpose software "R.F. Plug-ins Gear Drawing Tool Ver.3.0 for Rhinoceros" and "thinkdesign Ver.8.0". Finally, feature-based parametric solid modeling, transformation of CAD data to CAM are discussed. The research result has been applied to the three-dimensional (3D) CAD and numerical control (NC) manufacturing of gears and timing pulleys in Araoka Co. Ltd. It shows that CAD/CAM is effective for special gears or small batch processes of gears used in prototype machines.