地脚螺栓蠕变松弛对大型数控机床几何精度衰退的影响

发布时间：2018-02-26 05:11

  本文关键词： 地脚螺栓 蠕变松弛 几何精度 精度衰退 大型数控机床　出处：《西安交通大学学报》2015年09期 　论文类型：期刊论文

【摘要】：针对大型数控机床地脚螺栓蠕变松弛的问题,建立了分布式螺栓预紧力和蠕变力的计算模型及螺栓顺序预紧和室温蠕变的模拟模型。计算模型中考虑了螺栓常温蠕变特征和螺栓孔单元间的弹性交互作用,量化分析时利用了模拟模型,以揭示蠕变松弛对机床几何精度衰退的影响规律。结合20℃环境温度下拉拔实验获得了8.8级T型地脚螺栓的3个蠕变系数,再经9 000h蠕变模拟得到的地脚螺栓预紧力松弛比约为14.8%,床身导轨安装面直线度和平行度的相对衰退量分别为4.3μm和2.8μm。该结果表明,所建模型对大型数控机床基础件的螺栓预紧优化和几何精度保持能力的提升具有指导意义。
[Abstract]:Aiming at the problem of creep relaxation of anchor bolts in large NC machine tools, The calculation model of pretightening force and creep force of distributed bolts and the simulation model of bolt preload and room temperature creep are established. The creep characteristics of bolts at room temperature and the elastic interaction between bolt holes are taken into account in the calculation model. The simulation model is used to reveal the influence of creep relaxation on the geometric precision decline of machine tools, and three creep coefficients of 8.8 T type anchor bolts are obtained by drawing experiments at 20 鈩，

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