考虑多公差耦合的几何要素误差建模及产品装配精度预测

为了准确有效地实现零件几何要素误差建模,提出了一种基于多公差耦合作用下的几何要素误差建模方法.该方法采用小位移旋量(SDT,small displacement torsor)描述公差,针对平动公差与固定公差耦合建立几何要素误差模型,通过利用约束方程的不合格率p,推导各个误差分量参数的实际的分布规律,建立几何要素误差模型.采用雅可比旋量模型将该方法扩展应用于复杂装配体的装配误差建模中,实现了装配精度的预测.以顶尖尾座装配精度预测为例,验证了该方法的合理性及可行性.

Geometric element error modeling considering multi-tolerance coupling and accuracy prediction of product assembly

In order to accurately and effectively realize the geometrical element error modeling of parts, a geometric element error modeling method based on multi-tolerance coupling is proposed in this paper. Small displacement torsor (SDT) was adopted to describe the tolerance, and the geometric element error model for the translation of the translational tolerance and the fixed tolerance was established. By using the failure rate p of the constraint equation, the actual distribution of the parameters of each error component was derived and the geometric element error model was built. The method was extended to the assembly error modeling of complex assemblies by using the Jacobian spin model, realizing the prediction of assembly accuracy. The rationality and feasibility of the method are verified by the prediction of the assembly accuracy of the top tailstock.