考虑几何公差的设计与工序公差并行分配研究

Research on Concurrent Design and Process Tolerances Allocation in Consideration of Geometrical Tolerances

设计与工序公差并行分配大多数集中于尺寸公差的并行设计上,较少考虑几何公差。研究的目标是对并行公差模型进行扩展研究,以便考虑几何公差要求。首先,根据几何公差各自的特点,将其转换为等效尺寸公差或仅作为附加加工约束处理;然后,以期望质量损失和制造成本之和最小为目标函数,以产品功能约束、几何公差约束和经济工序边界约束为约束条件,对并行公差分配模型进行扩展,并采用非线性规划技术对扩展后的模型进行求解以获得优化的设计公差和工序公差值;最后,通过滚轮装配的并行公差优化分配实例验证该方法的有效性。

Design and process tolerances concurrent allocation mostly focuses on the concurrent design of dimensional tolerances,with little consideration for geometric tolerances.The objective of this paper is to extend the concurrent tolerancing model to consider geometrical tolerance requirements.Firstly,the geometrical tolerances are either converted into equivalent dimensional tolerances or only treated as additional machining constraints based on their respective characteristics.Then,the concurrent tolerancing model is extended based on ensuring the fulfillment of the product’s functional requirements,taking the combination of expected quality loss and manufacturing cost as target function,and taking the functional constraints,geometrical tolerance constraints and process bound constraints as the constraint conditions.After having established the concurrent tolerancing model,the nonlinear programming technique is employed to solve this extended model to gain the optimal design and process tolerances.Finally,an example of wheel assembly is given to illustrate the validity of the suggested method.