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基于汽车车身柔性薄板零件装配建模方法,建立柔性薄板零件公差优化设计方法。根据柔性薄板零件测点装配偏差与各偏差源间的确定性模型,综合得到测点装配偏差的方差与零件制造方差和夹具定位方差之间的模型,以零件测点平均方差为公差设计函数,工序能力指数和零件制造方差比为约束函数进行零件公差优化设计,并采用车身后地板装配进行应用分析。结果表明,搭接焊接结构的零件公差设计需同步进行,对接焊接结构零件公差设计各自独立进行,而角接焊接结构的零件公差设计则先进行其中对接零件公差设计,然后进行搭接零件公差设计;搭接焊接结构中零件间刚度差异比较大时,刚度小的零件公差可以取相对更大的公差。
Based on the assembly modeling method of automobile body flexible thin-plate parts, the tolerance optimization design method of flexible thin-plate parts is established. According to the deterministic model between assembly point deviation and each deviation source of flexible thin-plate parts, the model of variance between assembly point assembly deviation and part manufacturing variance and fixture positioning variance is obtained synthetically. Taking the variance of part measurement point as the tolerance design function, Process capability index and variance ratio of manufacturing parts for the constraint function to optimize the design of part tolerances, and the use of vehicle body rear floor assembly for application analysis. The results show that the design tolerances of lap welding structure should be synchronized, but the tolerance design of butt welding structure parts should be carried out independently, while the tolerance design of the angle welded structure should be designed first, and then the tolerance design of lap joint ; Lap welding structure when the stiffness difference between parts is relatively large, the stiffness of small parts tolerance can take a relatively larger tolerance.