双肘杆压力机误差建模及公差优化分配

Error Modeling and Tolerance Allocation Optimization of Double-Knuckle Press

近净成形要求压力机具有较高的输出精度,为此需要对其进行精度设计,即建立其误差传递模型,从而经济合理地分配各零部件的精度参数。采用矩阵法构建双肘杆压力机传动连杆误差模型及多体系统理论构建其框架几何误差模型;在此基础上,基于误差独立作用原理建立压力机传动连杆-框架综合误差模型,通过灵敏度分析找到影响其输出精度的关键因素;综合考虑加工成本和机构输出可靠性对关键部件公差进行优化分配,进而给出在各零部件加工及装配中应采取的措施。案例研究结果表明,该方法能够建立压力机传动连杆-框架综合误差模型,优化后各关键部件公差均有所增大,兼顾了经济性能和精度性能。

It is necessary to design precision carefully due to the high precision during near net shaping,that means an error model need to be set up,thus main parts can be allocated economically and reasonably. Based on the matrix method,the error model of duoble-knuckle press transmission link was built, as well as the geometric error model of press framewhich was constructed based on multi-body system theory. On the basis of the twindependent contributions theory,thepress transmission link-frame error modelwas established. Then the key factors affecting output precision were figured out through sensitivity analysis. Combined withminimum manufac4uring cos4and reliabili4y of machine ou4pu4, 4 he 4 olerance of main par4s wasoptimized. Measure that fit different parts were given. The results show that the method can be used for error modeling of the press,and meet the requirement of economics and accuracy.