芯轴参数对薄壁管数控绕弯成形壁厚的影响研究

Effect of Mandrel Parameters on Wall Thickness of Thin-walled Tube in NC Rotary Bending Forming

薄壁管绕弯成形中,芯轴参数是影响管坯成形质量的重要因素。本文建立了薄壁管数控绕弯成形有限元模型,分析了芯轴直径、芯头间距、芯头宽度等工艺参数对管坯壁厚变化的影响规律。结果表明,随着芯轴直径的增大,弯管外弧壁厚减薄率增加,而内弧壁厚增厚率几乎不变;球头间距和球头宽度对管坯壁厚减薄的影响比较显著,外弧壁厚减薄率随着芯头间距和芯头宽度的增加而增大,当芯头间距增加2 mm时,外弧壁厚减薄率增加3%。在相同芯轴参数的成形条件下,管坯外弧壁厚减薄率比内弧壁厚增厚率更敏感。

The mandrel parameters are important factors of influencing the tube blank quality in rotary bending forming ofthin-walled tube. The finite element model of thin-walled tube in NC rotary bending forming was established. The influencinglaws of mandrel parameters （the diameter of mandrel, core head spacing and core head width） on wall thickness variation wereanalyzed. The results show that the thinning rate of outer wall thickness increases with the increase of diameter of mandrel, butthickening rate of irmer wall thickness is almost invariant; the influence of ball head space and bali head width on the thinningof the tube blank wall thickness is obvious. The thinning rate of the outer wall thickness increases with the increase of the corehead distance and the core head width. When the distance between the core heads is increased by 2 rnm, the thinning rate ofouter wall thickness is increased by 3%. And the wall thinning rate of outer wall thickness is more sensitive than thickeningrate of inner wall thickness under the forming conditions of same mandrel parameters.