双向偏心轴楔横轧成形数值模拟研究

基于Deform-3D软件建立双向偏心轴楔横轧成形的有限元模型,分析双向偏心轴楔横轧的成形原理,研究成形角、展宽角和坯料温度对偏心距的影响规律。应用MATLAB程序进行非线性拟合,验证双向偏心轴楔横轧成形的可行性。研究结果表明,成形角为31°、展宽角为6°、坯料温度为1 150℃时,双向偏心轴的楔横轧成形质量最优。     

楔横轧工艺成形阶梯轴类件杆部拉断理论分析

利用上限原理和最小能量原理 ,获得了楔横轧工艺成形阶梯轴类件杆部拉断的条件。同时研究了楔横轧变形时杆部拉断与变形程度(εf)、成形角(α)、摩擦因数(m)值以及整形段相对长度(L/Rf)的关系。从而为估测楔横轧成形阶梯轴类件时轧件杆部是否能被拉断提供了理论判据     

楔横轧工艺成形阶梯轴类件杆部拉断理论分析

利用上限原理和最小能量原理,获得了楔横轧工艺成形阶梯轴类件杆部拉断的条件。同时,研究了楔横轧变形时杆部拉断与变形程度（εf),成形角（α）,摩擦因数（m)值以及整形段相对长度（L／Rf)的关系。从而为估测楔横轧成形阶梯轴类件时轧件杆部是否能被拉断提供了理想 判据。     

横轧非回转体轴类件辊型曲线方程

楔横轧非回转体轴类零件是楔横轧近净成形和精确成形的突破性和创新性发展,而轧辊的辊型则是非回转体轴类零件楔横轧成形的基础和关键.在分析楔横轧非回转体轴类件成形工艺原理的基础上,提出“单阶段”楔横轧非回转体轴类零件新工艺;根据轧制过程中轧件与轧辊的相对共轭运动关系推导出楔横轧非回转体轴类件的辊型曲线方程;针对一典型非回转体轴类零件在试验轧机上进行轧制试验.试验结果表明,“单阶段”楔横轧生产的非回转体轴类件主要尺寸精度达到要求,且内部无明显缺陷,这说明“单阶段”楔横轧非回转体轴类件新工艺是完全可行的,且利用辊型曲线方程加工的辊型可以轧制出符合尺寸要求的非回转体轴类件,因而是实现非回转体类零件少无切削加工,改善劳动条件、节材降耗的优质工艺方法.     

楔横轧楔入段端面移动量规律

楔横轧多楔轧制是内楔和外楔同时对轧件进行径向压下、轴向延伸的塑性成形.随着交通运输业的飞速发展,火车轴、汽车半轴等长轴类零件的需求量与日俱增,采用楔横轧多楔工艺成形长轴类零件,具有显著节省辊面、减小设备体积、生产效率高、节材、降低成本等优点.为了充分发挥多楔显著节省辊面的优点,保持内外楔同时起楔,就必须要准确弄清楔入段移动量的变化规律.采用弹塑性有限形变有限元数值方法,根据实际工况模拟楔横轧轧制过程,分析楔入段移动量的变化规律,详细阐述各工艺参数对移动量的影响规律,并与试验测试结果进行比较,得到楔入段端面移动量的变化和影响规律.研究结果为楔横轧多楔同步轧制模具设计提供了重要的理论依据,进一步完善了楔横轧多楔轧制理论.     

楔横轧在汽车等轴类零件上的应用与发展

一、楔横轧技术简况1.楔横轧技术的简要历程20世纪50年代,由原捷克国发明了楔横轧轴类零件成形工艺并首先应用于汽车、五金工具等零件的生产,其技术与设备出口英国、美国等国家,成为国际上公认的轴类零件成形新技术,由于技术复杂等原因,至今只为少数国家全面掌握。     

轧辊直径对楔横轧大型轴类件应力应变影响分析

合理选择轧辊直径是楔横轧成形大型轴类件的重要技术指标,采用ANSYS/LS-DYNA有限元分析软件,对楔横轧轧制大型轴类件进行模拟,分析轧辊直径对楔横轧大型轴类件应力应变影响规律,阐明轧辊直径对于楔横轧大型轴类件轧件质量的影响程度,研究结果为实现大型轴类件楔横轧经济化生产提供理论依据.     

楔横轧多楔成形汽车半轴工艺可行性分析

分析多楔成形长轴类零件时内/外楔对接段的各种形状及其优缺点,建立了楔横轧多楔成形汽车半轴的三维有限元模型.通过选取合理的轧制工艺,模拟楔横轧多楔轧制汽车半轴的过程,获得了内/外楔之间过渡光滑的汽车半轴.结果表明:楔横轧多楔成形汽车半轴工艺是可行的,该研究为多楔成形半轴的模具设计提供了理论依据.     

楔横轧二次楔轧制大断面收缩率的应力应变场分析

利用有限元软件DEFORM-3D,基于三雏刚塑性的有限元理论,对大断面收缩率轴类零件成形过程成功地进行了楔横轧二次楔轧制成形的数值模拟,模拟所得的轧件形状与实际零件基本相同,给出了楔横轧二次楔轧制过程的应力应变分布等重要信息。模拟结果表明：二次楔轧制大断面收缩率轴类零件的心部发生了很大变形;二次楔轧制中间横截面受的横拉应力时间较长、值较大,所以轧件中心更容易产生内部缺陷。     

工艺参数对楔横轧接触区表面应力的影响分析

为深入探明楔横轧接触区变形规律，实现零件楔横轧近终成形，采用有限元数值方法模拟楔横轧轧制过程，获得稳定轧制过程中的接触区的面力和位移，进而求出轧制接触区表面应力。在此基础上，较详细地分析了展宽角、成形角和断面收缩率三个主要工艺参数对接触区表面应力的影响规律，并对所建立的有限元计算模型进行了实验验证。研究结果对合理选择楔横轧工艺参数以及实现零件的精确成形具有重要的现实意义和应用价值。     

三环减速器的工作原理与功率流分析

通过对三环减速器高速轴曲柄转矩变化规律的分析，研究了三相并列平行曲柄输入机构克：服死点、实现连续运动的工作原理，并对减速器中的功率流动和偏心套微动磨损现象进行了探讨。     

Analysis of a cross wedge rolling process for producing drive shafts

The paper discusses the problems of forming parts such as stepped shafts by cross wedge rolling (CWR). In industrial practice, this rolling process is performed at stages, i.e., in several passes, when large cross-sectional reductions are involved. The same can also be done using a different design of this forming process, namely, multi-wedge cross rolling (MWCR), in which the workpiece is simultaneously formed by several pairs of tools (wedges). This paper compares the above two methods with respect to forming a drive shaft. Wedge tools used in both forming processes are described, and the numerical results of the simulations performed to verify the adopted solutions are reported. The results demonstrate that the MWCR method offers more advantages than the classical CWR technique. Consequently, MWCR is then verified in experimental tests. The experimental results confirm that parts such as stepped shafts can be formed by the MWCR method.     

双轴输入式内齿行星轮行星传动的动态受力分析

本文论述了双轴输入式内齿行星轮行星传动的传动原理和动态受力分析，推导出了考虑惯性力、重力时两转臂偏心轴作用力的计算公式和输入轴最大支座反大的计算式。并绘制了转臂偏心轴作用力的变化曲线图。     

Study on the progressive forming mechanism of multi-step shafts based on convex-end billet in the cross wedge rolling technology

The deforming process is complicated and both the end concave and the central defect can be easily formed in multi-step shafts shaped by the cross-wedge rolling technology. To realize the accurate forming of multi-step shafts without stub bar, this article breaks the bondage of traditional flat-end billet, and introduces into convex-end billet. Based on established mechanical models and the damage computation principles, the distribution and change features of stress fields, strain fields and microstructures in different segments of the multi-step shaft during the progressive forming process are analyzed, and the location of the central defect is predicted. It is found that the concave depth of shaft ends decreases as the length of the convex-end of billet increases, the microcosmic grains are affected by the section shrinkage of the shaft segments and the larger the section shrinkage is, the smaller the size of the microcosmic grain will be. It records the longest duration of maximum stress, the largest fluctuation of lateral stress and the most frequent cycle of transverse strain in the multi-step shaft end and therefore the central defect is most likely to occur. The research findings settle a dependable theoretical basis for enhancing the molding quality and realizing the accurate forming for multi-step shafts in cross wedge rolling.

     

支撑轴偏心套自由回转的三环减速器弹性动力学分析

在考虑高速轴变形、行星轴承变形、输出轴支承轴承变形、齿轮副变形及偏心套误差等因素的基础上,又计入了环板的变形,推导了各变形间的协调条件,建立了支撑轴偏心套自由回转的三环减速器传动系统的弹性动力学方程,求解了系统各环节的受力和固有频率,并与原结构的系统动力学性能作了比较。仿真结果表明,取消支撑轴上的键联接,可以消除该轴上偏心套的微动磨损现象,且一般不会导致系统受力性能的恶化,但是此举会大大降低系统第一阶固有频率。     

渐开线花键轴冷滚轧轮的设计

通过对渐开线花键冷滚轧加工原理的分析，提出了冷滚轧轮设计原理，推导了加工奇数齿和偶数齿花键时滚轧轮凸棱齿形的计算方法，介绍了冷滚轧轮的设计方法及步骤。     

三轴式星型内齿行星传动的弹性动力学建模

综合考虑了三轴式星形内齿传动的各轴的弹性、轴承的弹性、齿轮啮合弹性以及输入轴和支承轴的偏心误差,通过5个子系统的运动方程组装获得三轴式星形内齿传动的弹性动力学方程.为系统地分析三轴式星形内齿传动的动力学行为奠定了理论基础.     

畸变测量中偏心角的调整技巧

测量光学系统畸变的方法较多,精密测角法为常用的一种测量方法。为了准确地测试光学系统的畸变量,偏心角的调整极为重要。如果存在偏心角则影响光学系统畸变的测量结果,当偏心角偏大时将可能得出错误的结论。然而偏心角的调整是一项较为复杂的过程,现从原理上对偏心角进行分析,得出一种快速而简便的畸变偏心角调整方法,并给出合理的残余偏心角修正公式,使测试结果更加合理。     

Fabrication of micro spur gears by step powder extrusion of Zn-22wt%Al powder without sintering process

Micro spur gears were fabricated using the LIGA process and step powder extrusion without sintering. It is important to manufacture micro dies with high aspect ratios and determine the appropriate extrusion conditions for the micro-forming process. Micro-extrusion dies with close tolerance and long bearing length were produced by the LIGA process. Superplastic Zn-22wt%Al powders can deform under low stresses and exhibit a good micro-formability (average strain rate: 10^?3s^?1; constant temperature: 250°C). These powders were compacted to a cylinder (diameter: 3 mm; height: 10 mm) under 10kN compressive force, and sintered at 350°C for two hours. Micro spur gear shafts were not produced upon extrusion because of the high working pressure on the die surface. For the reduction of the forming load, step powder extrusion was carried out on the compacted powder without a sintering process, but controlling the temperature dwelling period. This process has succeeded in fabricating micro-gear shafts.     

水轮机主轴轴肩槽加工刀具改进

以某水电站主轴为例,介绍了轴肩槽加工过程中的难点,并进行了分析,给出了解决办法。