摘要
提出了一种基于关键特征和图的零件公差建模方法。定义了零件的关键特征和参考坐标系;基于关键特征和扩展型的有向图,通过定义关键特征之间的公差关系、公差属性、公差变动方向等,实现了公差元的表示;采用图的和运算,建立了零件公差模型。该模型有利于公差链的生成与分析,并采用实例验证了该方法的有效性。
The desired requirements for a tolerance model for part are： completeness, compatibility, computability and validity. We aim to meet these requirements in a way different from past researchers. Past researchers dealt with dimension tolerance, form tolerance and position tolerance separately. We build a unified tolerance model that deals with these three tolerances simultaneously. Our approach is based on Key Features （KFs） and directed graph. KFs include point KF, line KF and plane KF. We build a meta-tolerance model with five kinds of information： （1） a set made up of KFs; （2） a set made up of lines which connect KFs; （3） clear designation of type of tolerance： dimension, form or position; （4） attributes of tolerance which include size and type of tolerance value; （5） variational direction of KF, where variational direction is represented by unit-vector. We build our tolerance model with the above-mentioned meta-tolerance model and the principles of sum operation in graph theory. So a unified tolerance model comes into being. This model is propitious to representation of tolerancing experience from engineers and that from analysis of tolerance chain. As shown by an example given in this paper of a common .type of machine part, our approach does satisfy the desired requirements for a tolerance model for part： completeness, compatibility, computability and validity.
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
2005年第5期647-651,共5页
Journal of Northwestern Polytechnical University
基金
航空基金(01H53067)
西北工业大学青年教师创新基金资助
关键词
公差元
公差建模
关键特征
图论
tolerance model, meta-tolerance, Key Feature（KF）, graph theory
