中文摘要：

为提高无芯模旋压成形质量,引入变速成形技术,提出变进给比旋压成形方法.该方法的关键为获取与旋轮轨迹相适应的进给比设计方案,使成形时间与成形量相匹配,从而保证坯料充分成形.针对道次进给比设计,根据各道次平均环向应变量进行成形时间道次间分配,提出有利于提高形状精度的＂匀速变形原则＂和＂终道次充分成形原则＂.针对道次内进给比设计,根据终道次局部环向应变分布情况进行成形时间道次内优化分配,并提出有利于抑制形状误差的＂大环向应变充分成形原则＂.实验结果显示,在总成形时间不变的条件下,采用变进给比方法进行无芯模旋压成形可以将平均形状误差降低约47%,同时更好地保持坯料壁厚,防止坯料过度减薄.

英文摘要：

To improve forming qualities of die-less spinning,the varying speed forming technology was introduced to develop a novel varying feed ratio spinning method.The key to this approach was to seek a proper schedule of feed ratios according to the geometry of roller path profiles,so that the processing time of each spinning phase could match the amount of processing quantity and the blank could be sufficiently formed.To design the feed-ratio schedules of spinning passes,the optimal allocation algorithms of the processing time was developed according to the average hoop strains of each pass,based on which the uniform speed deformation principle and the sufficiently forming principle for the final pass were proposed to improve the shape precision.In order to optimize the feed-ratio schedule of the final pass,the processing time was optimally allocated according to the local hoop strains,by which the localized difficult forming region could be sufficient deformed and the sufficient forming principle for large hoop strain part was proposed to restrain the shape deviation.The experimental results show that,with the processing time unchanged,the average shape error could be decreased by about 47% through the varying feed ratio processing method in die-less spinning,while the wall thickness is well kept from excessive thinning.