孔轴配合的精度预测与公差优化设计∗

摘要

Taking cylindrical hole shaft j oint surface as the research obj ect,the actual error model of hole shaft j oint surface with coupled tolerance was studied based on the new generation of GPS standard system.Taking cylindricity for instance,combining with the cylindrical form error evaluation method in the GPS standard,the external associated size actual change interval solving model of the cylindrical hole shaft surface was established,and the effect of actual error on fitting property was analyzed by using Monte Carlo method to simulate the random error.The formation mechanism of hole shaft j oint surface er-ror under the coupling effect of three kinds of tolerance,including direction tolerance and position toler-ance,was analyzed,the actual error models of cylindrical hole shaft j oint surface under different fitting properties were established,and the actual change interval of each error component of the j oint surface and actual fitting property were obtained.Hole shaft actual assembly accuracy prediction in the design phase was achieved by taking the tolerance optimization design of the hole and shaft parts with the actual hole shaft j oint surface accuracy and fitting property requirements as the constraints,and hole shaft processingcost as the obj ective.Finally,the feasibility and practicability of this method were verified with an example of hole shaft assembly accuracy analysis and tolerance optimization.%以圆柱形孔轴配合的结合面为研究对象，研究了新一代 GPS 标准体系下多公差项的孔轴配合实际误差模型。以圆柱度为例，结合 GPS 标准中圆柱面形状误差的评定方法，采用蒙特卡洛法模拟误差的随机性，建立了孔轴圆柱面体外拟合尺寸实际变动区间求解模型，并分析实际误差对配合性质的影响。分析了包括方向公差(或位置公差)在内的三类公差耦合作用下孔轴结合面误差的形成机理，建立了不同配合性质下的圆柱形孔轴结合面的实际误差模型，获得了结合面误差分量的实际变动区间以及实际的配合性质。实现了在设计阶段对孔轴实际装配精度的预测。以实际的孔轴结合面精度与配合性质要求为约束，孔轴加工成本为目标，进行了孔轴零件的公差优化设计。最后以一孔轴配合的装配误差分析与公差优化为例，验证了该方法的可行性与实用性。