基于特征的三维装配尺寸/公差链生成研究

针对目前基于特征的尺寸/公差链生成主要集中于二维的情况,本文进行了三维装配尺寸/公差链生成的研究.基于特征的尺寸工程语义的表达以及基于特征自由度变动的三维公差信息的表示,给出了三维尺寸/公差信息的公差图存储结构;在分析零件配合关系及建立装配特征关联矩阵的基础上,提出了根据产品装配特征和指定封闭环信息的装配尺寸/公差链自动生成算法,该算法考虑到零件特征配合的方向性,可以简化装配尺寸/公差链自动生成的复杂度;通过实例验证了所提出的算法,证明有效.

Features-Based Generation of 3D Assembly Dimension/Tolerance Chain

The generation of an assembly dimension/tolerance chain is the basis of tolerance analysis and synthesis.Differing from the current research which mainly concentrates on two dimension(2D) chains,this paper discusses the generation of a 3D dimension/tolerance chain.The engineering semantic representation of dimensions and 3D tolerances introduced are based on features.The tolerance chart is given as a storage chart of 3D tolerances.With analysis of assembly relations of parts and establishing associated matrix of assembly features and tolerance charts,an algorithm to generate the dimension/tolerance chain automatically is proposed according to the information of the assembly features and closed-link.That the direction of feature-dimension can reduce the complexity of the algorithm has been taken into account.Finally,a case study is given to validate the proposed algorithm.