Geometric Product Specification of Gears: The GeoSpelling Perspective

Gears as the key transmission parts of machineries are widely used in mechanical and aeronautical fields. GeoSpelling, a framework standardized as ISO 17450-2005 supported tolerancing process by a set of concepts and mathematical algorithms, is a coherent and complete model to manage the shape variations of geometrical parts. Considering current gear specification standards incline to inspection convenient ignoring tolerance quality control, so it is a realistic necessary to develop a coherent gear specification model based on GeoSpelling language. This model should not only consider integrating functional requirements involved in design stage but also be able to correspond to manufacturing and inspection procedures.In this paper a new approach based on discrete geometry is introduced to design gear specification model. It is also focus on a perspective discussion on how SSA (Statistical Shape Analysis) method could be a solution to analyze the gear integrated errors into different individual errors, such as tangential composite error, tooth-to-tooth tangential composite error, pitch accumulated deviation, tooth-to-tooth pitch accumulated deviation and geometric eccentricity.The fundamentals mentioned above provide a reliable methodology for analyzing gear manufacturing errors. As a result it is able to enhance the computational processing capability and metrological traceability for gear quality control.