卡门曲线回转体旋压工艺参数优选试验研究

针对生产卡门曲线薄壁回转体零件旋压成型中存在的大端不贴模、拉裂、外表面起皮等旋压缺陷,确定了旋压工艺方案,从旋轮工作角、进给比及材料热处理等角度进行了不同工艺参数的试验研究,通过试验找出了最优的旋压工艺参数.试验结果对提高旋压件质量有良好的指导作用.     

三旋轮缩颈旋压机的设计

根据缩颈旋压机的运动特点,分析了旋轮数目对旋压结果的影响,旋轮布局对旋压质量的影响;并对旋轮与旋轮芯轴之间的连接设计,旋轮主轴与旋轮芯轴的结构设计等作了特别说明。     

回归分析普通旋压筒形件的成形性

筒形件普通旋压中,制品常出现板材拉薄开裂和板材失稳起皱等成形性重缺陷。通过对铝合金材料筒形件普通旋压试验,发现板厚比t_0/d、旋压比D_0/d、旋轮移动速度V、旋压初角θ_0、旋轮移动距离p等多种加工参数对产品成形性影响很大。因此对生产实践和试验中获得的原始数据进行了计算机多重回归分析,得到了确保产品成形性的最适工艺参数。     

超半球壳体多道次拉深旋压工艺研究

针对1060超半球壳体基于板坯多道次拉深旋压进行成形性分析,提出两模法和两轮法的旋压成形试验方案,并设计不同旋压试验方案的芯模和旋轮工装.通过MC2000型数控录返旋压机,分别采用R13、R20和R25、R8不同圆角半径的圆弧式旋轮对1060板坯进行两模法和两轮法的多道次拉深旋压成形试验.两模法旋压毛坯件的凸缘边减薄严重,成形效果差;两轮法旋压采用R25旋轮4道次快速进给,R8旋轮4道次中低速精整旋压的旋压工艺,其旋压件贴模度高,成形效果好.试验结果表明:两轮法旋压工艺能实现板坯经多道次拉深旋压成形为超半球壳体.通过降低芯模转速,调整进给比和降低道次减薄率,可以消除旋压成形过程中出现的反挤、波纹和起皮等缺陷.     

四边圆角形截面筒形件的旋压成形方法研究

基于导杆机构运动原理,提出了一种四边圆角形截面筒形件的旋压成形方法,运用高副低代的转化方法,建立了四边圆角形截面筒形件旋压成形过程中旋轮运动轨迹的数学模型,得到了旋轮及零件的机构运动关系;同时,对成形过程中旋轮运动轨迹进行仿真与计算,分析了旋轮个数与轮盘尺寸对旋压成形过程的影响;得出成形过程中有利于零件成形质量及改善轮盘速度波动情况的轮盘尺寸与旋轮数量,为四边圆角形截面筒形件的加工工艺研究提供了理论基础.     

旋轮与芯模间隙对内外齿旋压缺陷的影响规律

旋轮与芯模间隙是影响旋压件成形质量的重要工艺参数。离合器毂的内外齿形在旋压成形中易出现齿侧壁呈弧形、齿顶圆角不饱满等缺陷,提出采用齿侧壁弧形度?、齿顶圆角不饱满度χ等来定量表征上述缺陷的大小,并基于有限元软件ABAQUS对内外齿旋压成形过程进行了数值模拟,获得了旋轮与芯模间隙对齿侧壁呈弧形、齿顶圆角不饱满等缺陷的影响规律,并获得了特定条件下的旋轮与芯模间隙的最佳值。结果表明,随着旋轮与芯模间隙的减小,齿侧壁弧形度?、齿顶圆角不饱满度χ随之减小;当旋轮与芯模间隙值取齿顶壁厚的公称尺寸与下极限尺寸的中间值时,可满足齿形壁厚要求并最大限度改善成形缺陷。有限元模型结果与成形试验结果吻合度良好。     

基于正多边形截面薄壁零件旋压成形质量研究

基于新型非圆旋压成形方法,讨论正多边形零件旋压成形的旋轮对零件轮廓的成形轨迹方程。以等边三角形截面以及正五边形截面的旋压为例,研究新型非圆旋压成形方法在旋压过程中的主轴转速、旋轮进给比和道次三项工艺参数对正多边形截面旋压件壁厚差的影响。应用有限元软件进行仿真分析,根据仿真结果分析正多边形旋压件的壁厚分布规律,即正多边形旋压件的壁厚呈周期性分布,最大壁厚发生在正多边形旋压件的圆角处。采用Box-Behnken实验设计方法设计仿真实验,根据仿真数据对零件的壁厚差进行方差分析,建立了关于壁厚差的预测模型并对其进行优化,最后进行多组仿真研究用来验证模型准确性。结果表明主轴转速、旋轮进给比、道次对正多边形零件壁厚差的影响显著,主轴转速与壁厚差呈正相关,而进给比壁厚差呈负相关,道次对壁厚差的影响先减小后增加。     

薄壁油缸QXK63-10数控强力旋压机旋压工艺研究

金属旋压工艺的原理是将被加工金属坯料套在芯模上,芯模随机床主轴旋转,旋轮沿芯模移动,在旋轮的压力下利用金属的可塑性,逐点将金属加工成所需要的空心回转体零件。尤其是薄壁管形件经旋压后可以达到较好的内孔直线度、表面粗糙度及较高的尺寸精度。另外,经旋压加工后的零件力学性能将会得到较大改善,表面残留应力可以控制在压应力状态,因此提高了零件的疲劳强度。     

铝合金轮毂旋压成形的数值模拟分析研究

铝合金轮毂旋压技术是近几年才发展起来的车轮成形新工艺方法,运用刚塑性有限元软件DEFORM 3D对铝合金轮毂旋压成形过程进行数值模拟,考察了特定减薄率、进给率等主要工艺参数对成形过程的影响规律。要保证铝合金轮毂旋压成形质量,关键是控制好三个主要工艺参数因素,即选择正确的进给率,合理的旋压道次,合适的旋轮圆角半径。通过综合分析数值模拟计算的结果,得出一组较合理的工艺参数,可以为旋压铝合金轮毂的实际生产提供理论指导。     

旋轮与芯模之间的间隙对锥形件强力旋压的影响

通过分析锥形件强力旋压时旋轮与芯模之间的间隙对旋压过程的影响。分析找出合适的偏离值以及减小不利影响的措施。     

ANALYSIS ON THE SPINNING FORCES IN FLEXIBLE SPINNING OF CONES

Flexible spinning is a new type of spinning process where spin-forming is performedwithout using a mandrel. Combining shearing and rolling processes, the calculation formulas of thespinning forces in flexible spinning of cones is presented. The effects of the main processing parame-ters, such as gripping force G applied to the blank by the inner roller, the feed rate of rollers f and theroundness radius of outer roller r_o, on the spinning forces are analyzed experimentally and theoreti-cally.     

ANALYSIS ON THE SPINNING FORCESN IN FLEXIBLE SPINNING OF CONES

Flexible spinning is a new type of spinning process where spin-forming is performed without using a mandrel. Combining shearing and rolling processes, the calculation formulas of the spinning forces in flexible spinning of cones is presented. The effects of the main processing parameters, such as gripping force G applied to the blank by the inner roller, the feed rate of rollers f and theroundness radius of outer roller ro, on the spinning forces are analyzed experimentally and theorelically.     

工艺参数对平板毛坯普旋成形的影响规律

基于ABAQUS/Explicit平台建立了符合实际的普旋三维仿真模型,利用此模型对平板毛坯普旋成形过程进行了模拟,研究了旋轮进给率、旋轮圆角半径、旋轮入旋角、板料厚度4个关键参数对平板毛坯普旋(第一道次)成形过程及旋压件质量的影响。结果表明:入旋角对板料的壁厚变化有较大的影响;旋轮圆角半径和板料厚度仅对板料的壁厚减薄率影响较大,对板料的壁厚增厚率影响很小;当旋轮进给率的值较小时,旋轮进给率对普旋成形过程影响不大。基于以上研究,最后得到了合理的工艺参数取值。     

滚珠丝杠副滚动体自旋运动分析

滚珠丝杠副滚动体自转运动中包含自旋和纯滚动,滚动体的自旋运动造成滚动体滑动。利用角接触轴承旋滚比的概念和目前对滚珠丝杠副自旋运动的研究情况,采用运动分析的方法分析了丝杠公称直径、接触角和螺旋升角对滚珠丝杠副自旋运动的影响情况,为设计和选用滚珠丝杠副参数提供了参考。     

三维非轴对称偏心类管件旋压成形时的变形力分析

采用主应力法建立了三维非轴对称偏心类薄壁管件旋压成形时的变形力的理论计算公式,并对旋轮公转角度γ、道次偏移量δ等成形工艺参数对旋压力变化的影响进行了理论分析。结果表明,在偏心类管件旋压过程中,旋压力随旋轮公转角度γ作周期性变化,其变化的幅度取决于道次偏移量δ的大小。对工件道次偏移量δ、旋轮进给比f和名义压下量Δ等主要成形工艺参数对最大旋压力的影响进行了理论分析和试验研究,理论计算结果与试验结果吻合较好。     

Study on compound spinning technology of large thin-walled parts with ring inner ribs and curvilinear generatrix

Given their rapid development, aerospace and other high-tech industries are in urgent need of process technology for large complex thin-walled shells represented by large thin-walled parts with ring inner ribs and curvilinear generatrix. To make up for the deficiency in existing forming methods, this paper presents a compound spinning process that integrates counter-roller spinning, multi-neck spinning, and hot spinning. The finite element models for the counter-roller spinning and multi-neck spinning forming of such parts are established, and these models can simulate the influences of different spinning process parameters on workpiece maximum equivalent stress and maximum ovality. The 2A12 aluminum alloy tube blank is used in this paper. The process parameters for obtaining the counter-roller spinning for such parts are as follows: a feed ratio of 1.0 mm/r and a roller nose radius of 8 mm. The process parameters of multi-neck spinning are as follows: a feed ratio of 3.0 mm/r and a roller nose radius of 80 mm; and the forming temperature of hot spinning is 200–250 °C. Verification by a compound spinning test found that the numerical simulation results are consistent with the process test results. The process parameters can be used for guiding the actual production of large thin-walled parts with ring inner ribs and curvilinear generatrix.     

Finite element simulation and experimental investigation on the forming forces of 3D non-axisymmetrical tubes spinning

3D non-axisymmetrical tube (NAT) spinning is a kind of new spinning technology, which breaks through the restriction that only axisymmetrical hollow parts could be produced by traditional spinning technology. The research on the spinning force aims to optimize the machine design and the processing parameters selection. The neck-spinning process of the 3D NAT is simulated by 3D elastic–plastic finite element software, MARC. The characteristics of the neck-spinning force of 3D NAT are compared with that of the axisymmetrical tube (AT) spinning. The effect of the main forming parameters, such as offset amount, oblique angle, nominal reduction of blank radius, feed rate and path direction, on the spinning forces have been studied theoretically and experimentally. It shows that during 3D NAT spinning, the spinning forces varies periodically with the revolution angle of the roller around the blank; the spinning force during backward path spinning is greater than that of forward path spinning. The simulation results conform well to the experimental ones.     

An analysis of force distribution in shear spinning of cone

An analytic model for calculation of shear spinning force incorporate factor of over-roll (press down) of the blank is derived. The effects of blank thickness, roller nose radius, mandrel revolution and roller feed on the spinning force are discussed. Results obtained from calculation were compared with the experiment and other theoretical predictions. It is found that the present findings yield optimum results.     

Effects of processing parameters on the surface quality of square section die-less spinning

In view of the importance of the surface quality in the application to the square section die-less spinning, the effects of several key parameters which include roller path, half-cone angle, and roller nose radius on the surface quality are investigated. Through the geometric model of residual height, the effect law of the roller path is obtained: the surface quality increases with the decrease of the axial distance of two adjacent slices. Then the finite element model of the square section die-less spinning is established, and the normal force and axial strain states in the deforming process are adopted to predict the relationship between the surface quality and the half-cone angle. Combined with the residual height model and finite element analysis, the roller nose radius’ effect on the surface quality is also obtained. Enlargement of the two parameters can improve the surface quality. All the analysis results are verified by the surface waviness test of the specimens from the workpiece after spinning.     

环件辗扩过程的导向辊控制工艺及设备的研究

导向辊的控制在环件辗扩中有着重要意义.对现有的导向辊控制方式及其存在的问题进行了分析,通过对导向辊运动轨迹的分析,提出了一种新的导向辊控制工艺,并给出了该控制工艺的设备实现方法.最后通过有限元分析软件ABAQUS对具体的环件辗扩实验进行了模拟分析,结果表明,采用该导向辊控制工艺进行环件辗扩可以得到较高质量的环件产品.