关键词: 几何公差, 配合约束, 旋量矩阵, 公差分配, 公差优化

Abstract: When the tolerance principle is a related principle,how to establish a quantitative conversion relationship from dimensional tolerances to geometric tolerances and realize the precise allocation of geometric tolerances is an urgent problem.By the qualitative analysis and quantitative calculation of the top-down distribution of geometric tolerances,the method of geometric tolerance allocation based on fit constraint was proposed.According to the constraints among fit tolerance,cross-reference tolerance and self-reference tolerance,the model of tolerance correlation based on fit constraint was constructed.Based on the above correlation,the design process model of geometric tolerance synchronous with the product structure was constructed.According to the order and surface type of assembly joints,the analysis method of spinor matrix was proposed,and the geometric tolerance constraint of correlating surface was generated based on the spinor matrix.By taking the geometric tolerance constraints,the machining precision constraint and the constraints of cross-reference tolerance values on self-reference tolerance values as constraints,and the minimum cost as the objective function,the genetic algorithm was used to optimize the geometric tolerance value.The distribution of geometric tolerances was carried out by taking the crankshaft piston mechanism as an example.After comparing with the empirical method,the economy and effectiveness of the proposed method were verified.

Key words: geometric tolerance, fit constraint, spinor matrix, tolerance allocation, tolerance optimization