Analysis of guide modes in vertical hot ring rolling and their effects on the ring’s dimensional precision using FE method

In the vertical hot ring rolling (VHRR) process, roundness, outer radius, and width spread are three important indexes to the formed ring’s dimensional precision. In this paper, features of the guide modes of the VHRR process, such as single fixed guide mode (SFGM) and single follow-up guide mode (SFUGM), are analyzed to investigate their effects on the ring’s dimensional precision. The geometrical models of all the guide modes are then established and reliable three-dimensional coupled thermal-mechanical elastic-plastic FE models of the VHRR process are developed in ABAQUS/Explicit. Some key technologies, such as the guide roller’s motion control, are reasonably dealt with. The research results show that: (1) The roundness of the rings rolled by SFUGM is obviously superior to that of the ring rolled by SFGM. (2) With the same feed amount, the outer radius of the ring rolled by SFGM is always larger than that of the rings rolled by SFUGM. (3) During the rolling process of the ring rolled by SFGM, severe eccentricity will exist at the ring’s center, which is not obvious in the rolling process of the ring rolled by SFUGM. (4) The average value of width spread of the ring rolled by SFGM is slightly larger than that of the rings rolled by SFUGM. The research results can yield an understanding of some phenomena in the VHRR process. The modeling methods presented in this paper have general significance in the study of the VHRR process of the ring with complex profile.     

Modeling of on-line measurement for rolling the rings with blank size errors in vertical hot ring rolling process

The size errors of the ring blanks have a considerable effect on the vertical hot ring rolling process and the ring products’ dimensional precision. In this paper, the geometric relationship between the ring’s outer diameter and the measuring roll’s displacement is studied, and then, the influence of the blank size errors on this geometric relationship is analyzed. Subsequently, a modeling method of the measurement model for vertical hot ring rolling process is proposed, that is, the ring’s outer diameter can be measured indirectly through the relations of the ring’s outer diameter with respect to the measuring roll’s displacement and the ring blank’s outer diameter. Using this modeling method, the on-line measurement model of a certain type of vertical hot ring rolling mill was established, and the verification experiments were also conducted. The experiments showed that this on-line measurement model could calculate the ring’s outer diameter precisely, and the absolute errors of the formed rings were less than ±1.5 mm. The research results of this paper have general significance for the on-line measurement and process control of vertical hot ring rolling process.     

Numerical simulation and experimental study on geometry variations and process control method of vertical hot ring rolling

The accurate geometry and effective control during the ring rolling process are the prerequisites for the ring products’ precise forming. In this paper, the interaction modes and rules between ring and rolls in vertical hot ring rolling (VHRR) process are analyzed, and the change laws of the ring’s geometry are studied. Based on the ABAQUS/Explicit software and its subroutine VUAMP, the finite element (FE) model of the VHRR process with measurement and control is established. Then, the ring rolling process of a groove-section profile ring is simulated. During the simulation, the ring’s outer diameter, roundness error, and the stability of the rolling process are detected in time, and the close-loop control of feed plan of the drive roll and measuring roll are also employed. The results obtained show the following: (1) Four feed stages are divided by means of a step-down feed movement, that is, bite stage, main rolling stage, precise forming stage, and sizing stage. (2) At bite and main rolling stages of the VHRR process, the ring’s center swings in a spiral line, and the rolling process is unstable, the ring’s roundness becomes worse, while the process is entering the precise forming stage, by means of the guide roll, the rolling process becomes steady and the ring’s roundness tends to be better. (3) The measuring roll contacts with the ring at the main rolling stage, afterwards, it is pushed back at the precise forming stage by ring’s growth. When the measuring roll meets the desired displacement value, a stop feeding command will be fed back, and the ring rolling process enters the sizing stage. At the sizing stage, the ring’s outer diameter still increases a little. (4) A series of VHRR experiments are conducted, and FE results are in good agreement with experimental results. The absolute errors of the ring’s outer diameter and the roundness are within 1 mm. The research results of this paper have practical significance to guide the VHRR production.     

环件冷辗扩中单辊随动导向运动规律研究

根据立式单导向辊随动导向冷辗环机的实际工况，建立了矩形截面环件和深沟球截面环件冷辗扩的运动学模型，分析两种环件的直径变化规律，研究了一定辗扩工艺条件下导向辊的运动规律。建立根据冷辗扩工艺来确定导向辊运动的一整套设计方法，并用MATLAB编写求解程序以求解所有的设计参数。精确地控制导向辊的运动规律有利于提高环件冷辗扩的精度。研究结果为冷辗环机的设计制造提供了依据。     

滚针轴承外圈滚道宽度测量方法的改进

滚针轴承外圈宽度通常通过手指塞规进行检测,由于滚针轴承外圈内部空间狭小,用手检测很不方便且效率低。针对以上问题,将宽度塞规装上手柄,代替手进入外圈内部测量滚道宽度,使测量简便、效率高。     

航空自润滑关节轴承的内锥面滚铆工具设计

依据航空标准的规定要求,研究了一种新型的翻边固定的滚铆工具,以实现滚轮纯滚动、表面质量好、对轴承启动力矩影响小的质量目标。根据速度合成定理研究了滚轮实现纯滚动的条件,设计了内锥面的滚轮;以滚铆MS14101-9关节轴承为例,研究了两种滚轮对轴承外圈座圈之间的贴合度、轴承内外圈等效应力、轴向推出力、翻边表面质量的影响;最后,通过虚拟正交试验,以航空标准规定的轴承启动力矩范围为约束,以翻边固定后的轴承内圈外球面位移变化量为优化指标,研究了内锥面滚轮的滚铆工具的翻边载荷和公转转速的参数优化。研究结果表明：内锥面滚轮的工具可实现良好的工艺质量;当翻边工具的翻边载荷4000 N、公转转速200 r/min时,可以保障翻边固定后工艺质量指标和轴承启动力矩在航空标准规定范围内。     

滚动轴承动态接触特性数值模拟中若干问题

滚动轴承运转过程中的动态接触特性与轴承使用寿命密切相关,目前主要是利用各种数值模拟技术开展轴承动态接触行为研究。通过在ANSYS/LS-DYNA研究平台上开展不同模型设计参数下滚动轴承动态接触特性的数值模拟研究,考察材料模型的设计、边界约束模式的选择和单元大小的定义等因素对数值模拟结果的影响情况。研究结果表明,由刚性体内外圈模型计算得到的滚子组最大应力仿真结果明显大于由弹性体内外圈模型得到的结果,且载荷方向上轴心位移变化起伏较大;采用外圈转动、内圈固定的边界约束模式时,轴承各组件上的最大动态接触应力值以及轴心在载荷方向的位移均高于采用内圈转动、外圈固定约束模式时的求解结果;单元大小也明显影响最终的动态模拟结果,较小单元尺寸下得到的应力结果明显大于较大单元尺寸下的模拟结果。研究结论可以为轴承动态接触特性数值模拟过程中模型构建方案的合理确定提供参考。     

球面滚子三点测量的应用

介绍了在生产现场用轴仪测量球面滚子轴承滚子滚动面曲率半径和球面曲率位置的方法,测量精确、简便、效率高。     

超大型环件径轴向轧制过程稳定性与圆度自适应控制方法研究

超大型环件径轴向轧制过程失稳、失圆等异常状态常导致轧环终止和产品质量波动。提出了轧环过程稳定性和圆度自适应控制方法,从历史数据中归纳人工控制经验知识,建立了基于锥辊转速模糊调节的轧制稳定性控制方法,制定了基于导向力反馈的轧制圆度控制策略。运用ABAQUS有限元软件和子程序二次开发,设计了轧环过程稳定性和圆度自适应控制子程序,建立了16 m超大型环件轧制过程控制有限元模型,仿真分析了锥辊转速模糊调节、导向力反馈以及基于限幅滤波的锥辊转速模糊调节+导向力反馈综合控制下的轧环过程偏移量和圆度误差变化规律,结果表明该方法与常规规划控制相比,环件偏移量减小了48.3%,圆度误差减小了61.8%。     

垂直轴风机圆锥滚子轴承有限元分析

基于有限元法在接触问题中的应用,对垂直轴风机顶部双列圆锥滚子轴承进行非线性分析.以轴承外圈的内表面和内圈的外表面为目标面,以滚子为接触面创建接触对。得到轴承Mises应力趋势及接触应力的变化规律,最大应力值出现在距外载最近的滚子上。对最大承载滚子环向接触应力的路径分析表明,应力分布曲线呈抛物线状,符合赫兹弹性体接触理论的分布规律。     

大尺寸环件高温测量技术研究

大尺寸环件毛坯在高温下轧制成型,为控制环件毛坯的形状、尺寸,需对环件进行在线测量,由于被测工件温度高,故采用激光非接触式测量。文章采用直射式激光位移三角法测量环件厚度,用激光测距法测量环件外径和内径,分别讨论了直射式三角法测量原理和激光测距原理;针对被测工件温度高以及环境温度高的特点,分析了温度对测量精度的影响,提出了提高测量精度的措施。     

立式轧环机轧制中环件运动学规律

提出在轧制过程中环件中心不在芯辊和驱动辊中心连线上的轧制几何模型，并基于此模型导出环件中心位移、速度、加速度、环件转动惯量及转速和转动加速度的计算公式，建立了环件的运动学参数与环件壁厚和轧制进给量之间的关系，为环件轧制过程的在线测量和控制提供理论依据。     

考虑锥向金属流动的大型锥形筒节轧制力计算模型

由于大型锥形筒节存在锥度,考虑金属沿锥向的流动,首先采用微分分层计算法和切块法建立了大型锥形筒节轧制力力学模型;然后基于ABAQUS有限元软件,建立了大型锥形筒节轧制过程仿真模型。模型计算结果和有限元仿真结果表明：力学模型计算轧制力与有限元计算总轧制力的相对误差在20%以内。对比分析了力学模型和有限元模拟计算单位轧制力的分布。通过分析芯辊和外辊的转速比,得出了所建力学模型的稳定轧制的适用范围。     

圆锥滚子基面球径与直径测量关系的探讨

圆锥滚子基面的球面半径与其滚动表面的直径之间,有着必然联系。通过深入探讨两者间的关系,可以为加工工艺的制定、产品的测量提供必要的依据。     

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.     

轧环机轧辊的设计

分析了轧环机轧辊尺寸对咬入、锻透、环件刚性、环件最大初始壁厚及设备能力的影响。在综合考虑各种因素的基础上,提出了轧环机轧辊设计准则,这对于环件轧制工艺设计有指导意义。     

梯形轴承外圈冷辗扩的有限元模拟

基于阶梯形环件轧制理论,初步设计模具、毛坯和工艺参数,应用Abaqus软件建立轧制的三维模型,并利用Abaqus/Explicit显式算法对阶梯形环件轴承外圈的冷辗扩成形进行模拟分析,揭示出梯形环件轧制缺陷的成形机理和轧制过程中金属流动的特性.并在KKD160精密辗环机上进行轧制试验,验证了毛坯和模具的形状合理.     

基于线结构光的三维垂线位移测量方法

垂线测量法是观测大坝变形位移的一种简便而有效的方法,在实际大坝变形监测中得到广泛应用。 针对现有垂线坐标 仪大多只能测量垂线二维位移且结构复杂的问题,本文提出了一种基于线结构光的三维垂线测量方法。 基于垂线测量中垂线 方向不变,利用线结构光测量原理实现垂线三维位移测量。 首先,本文采用线结构光测量获取垂线二维位移,然后基于垂线上 固定标志点的成像光线和垂线相交于一点的事实,综合垂线二维测量结果和通过相机内参数恢复的固定标志点成像光线方程, 实现垂线三维位移测量。 实验结果表明,本方法在水平面内 Y 方向上的位移测量精度为±0. 1 mm,在水平面内 X 方向和竖直 Z 方向上的位移测量精度达到±0. 05 mm,测量范围为 0~ 80 mm。 相较目前垂线位移测量方法,本文方法垂线位移测量精度和测 量范围更高,且测量结构简单。     

外球面轴承外圈冷辗扩有限元分析

基于环件轧制理论,分析外球面轴承外圈的冷辗扩工艺,应用Abaqus软件建立轧制的三维模型,并利用 Abaqus/Explicit显式算法对外球面轴承外圈的冷辗扩成形进行模拟分析,研究了不同的模具结构、尺寸和进给规范对成形过程的影响,揭示了外球面轴承外圈冷辗扩成形的机理.