冷轧管机主减速机传动齿轮的过盈联接计算

冷轧管机主减速机具有降速增扭的作用,为节省制造成本,主减速机中的大齿轮采用组装齿圈式的结构,通过热胀法把齿圈与轮芯组装在一起,而齿圈与轮芯的过盈联接则非常重要,需经计算确定合理的过盈量。鉴于此,以某大型冷轧管机为例,运用经典力学理论对主减速机传动齿轮的过盈联接进行计算和分析,提供一种切实可行的计算方法。计算结果表明,该配合设计在足够的安全裕度下可保证动力传递且不发生滑移,该研究为冷轧管机主减速机传动齿轮的过盈联接提供了技术支撑。     

酸轧机组卡罗塞尔卷取机卷筒圆锥面过盈联接失效分析与对策

针对卡罗塞尔卷取机存在的卷筒轴与空心套联接螺栓频繁断裂问题,通过现场调查和理论分析。认为断裂原因由卷筒轴与空心套联接的圆锥配合面过盈量不足所致。为保证卷筒轴工作扭矩的传递,通过分析保证传递扭矩所需的圆锥配合面最小过盈量,并经圆锥配合面的试装,检测过盈量对轴承游隙的影响,最终确定了既能满足轴承游隙要求,又能有效传递工作扭矩的卷筒轴与空心套圆锥配合面的过盈量数据,在现场实施后,取得了满意效果。     

高线粗轧减速机过盈锥套联接设计

阐述了高线粗轧机减速机过盈锥套联接的结构特点,并对其进行了力学分析和计算。与现有圆柱轴配键结构相比,液压过盈锥套联接结构具有:结构简单、定心性好、承载能力高、抗冲击性能强、可承受变载荷以及便于装配、调整和拆卸等优点。该结构已在国内某钢厂高线生产中获得应用。实践证明,该设计结构合理、运行可靠。     

过盈联结传递扭矩的可靠性

根据可靠性设计理论，建立了过盈联结传递扭矩的可靠性设计公式，对通过过盈联结传递载荷的一些重要联结提供了新的设计方法．为提高传递载荷的可靠性提供了新的途径．     

过盈联结传递扭矩的可靠性

根据可靠性设计理论，建立了过盈联结传递扭矩的可靠性设计公式，对通过过盈联结传递载荷的一些重要联提供了新的设计方法，为提高传递载荷的可靠性提供了新的途径。     

隔膜室盖强度的接触有限元分析

运用ANSYS软件对隔膜泵中的隔膜室盖进行接触有限元分析。建立隔膜腔、隔膜室盖以及联接螺栓的接触有限元模型,详细讨论载荷与边界条件的处理方法,应用ANSYS软件的螺栓预紧功能模拟隔膜腔和隔膜室盖的螺栓联接,对隔膜室盖强度的接触有限元法进行计算,得到隔膜室盖接近实际的应力。     

φ400机组轧管机齿轮座发热原因分析及其改造

对原齿轮 +座重新设计。滚动轴承代替滑动轴承 ,减少了起动力矩 ,便于安装、维护、润滑 ,检修时可整体更换 ,既快捷又方便。采用过盈联接传递大扭矩方法 ,结构简单 ,不需要任何紧固件 ,联结定心自位好 ,承载能力高 ,承受交变和冲击载荷性能好 ,安全可靠 ,满足连续生产所需要的最低寿命。     

过盈联结过盈量的计算与修正

为保证过盈联结的工作可靠性 ,确定过盈联结的过盈量除了考虑所传递的载荷以外 ,还应考虑其他条件因素对过盈的影响 ,以合理计算联结过盈 ,在满足联结件材料强度的前提下 ,提高过盈联结的可靠性     

过盈联结过盈量的计算与修正

为保证过盈联结的工作可靠性，确定过盈联结的过盈量除了考虑所传递的载荷以外，还应考虑其他条件因素对过盈的影响，以合理计算联结过盈，在满足联结件材料强度的前提下，提高过盈联结的可靠性。     

端面齿联轴器无键联接配合计算探讨

主要介绍了在冶金机械工程上常见的大过盈量无键联接,分析了其优缺点。并通过端面齿式联轴器的尺寸超差的实例来阐述如何通过大过盈配合的校核计算来进行质量判定。通过该计算校核,能更合适地设定过盈量,把控装配风险和质量,并为大过盈的无键联接厚壁圆筒类零件的生产、装配及检验提供了相应的借鉴资料。     

V形辊道的过盈配合设计及有限元模拟

运用圆柱面过盈联结的计算公式,简化设计了给定参数的V形辊道的辊身和辊轴的过盈配合。并运用有限元软件ANSYS WORKBENCH,对设计的V形辊道进行了模拟计算。模拟计算结果验证了设计的正确性。     

3-D simulation of metal forming processes with automatic mesh generation

The numerical simulation of industrial metal forming processes requires robust and feasible solution methods. In this context, any solution procedure must be able to handle three-dimensional problems with general contact conditions and severe deformations. The latter condition necessitates automatic mesh-generation abilities. At the same time, the simulation tool must be economical and user-friendly. In this paper, a solution procedure is introduced which is able to perform the numerical simulation of complex industrial metal forming processes without any interference. The procedure is based on the rigid-plastic finite element method and is primarily suited to the analysis of bulk metal-forming processes. To ensure a real automatic simulation, the numerical procedure is made robust by using Euler time integration, a Newton-Raphson solver which is coupled with a direct iteration solver, a linear contact algorithm and, finally, a completely automatic hexahedral mesh generation scheme. The method is implemented in the ANSI-C programming language. To demonstrate the effectiveness of the method an industrial application has been simulated: A spider produced from a cylindrical initial workpiece by cold radial-extrusion.     

平面一次包络环面蜗杆传动圆盘式给料机的传动效率

动力蜗杆传动的综合质量指标是承载能力和传动效率．通过平面一次包络环面蜗杆传动圆盘式给料机与普通圆柱蜗杆传动圆盘式给料机的效率实验，对比二者的差异，又通过蜗轮蜗杆啮合时接触线及接触线和滑动速度之间夹角的分析，说明平面一次包络环面蜗杆传动圆盘式结料机在效率上优于圆柱蜗杆传动圆盘式给料机．     

温度对整辊内嵌式板形检测辊过盈配合的影响

 在用整辊内嵌式板形检测辊检测可逆冷轧生产过程中带钢的在线板形状况时,板形检测辊的热变形影响辊体内孔面与传感器顶部间过盈配合面的接触状况,引起板形检测信号的间断消失。以整辊内嵌式板形检测辊为研究对象,应用有限元技术对冷轧可逆轧制各道次中检测辊辊体内孔面与骨架顶部过盈配合面各节点副的温度差值、径向相对位移进行模拟分析,获取温度差值对各节点副相对位移和传感器预压力的影响规律。分析结果表明,第3道次各节点副的温度差值最大,大部分节点副的径向相对位移超过配合过盈量,使得传感器预压力接近零,严重影响带钢作用在辊体表面的压力传递,容易造成板形检测信号的中断。     

Broad beam attenuation of kilovoltage photon beams: effect of ion chambers

In kilovoltage X-ray treatment, beam shaping and shielding normal tissue are accomplished by thin sheets of lead cutout, the thickness of which is selected based upon either published data or measurements. Available broad beam attenuation (BBA) data are found to be unsatisfactory and are the subject of this investigation. BBA is defined as the ratio of intensity with (I) and without (I0) attenuating medium for a large field in a phantom. BBA = I(x,t,E)/I0(x,0,E), where x is the depth of measurement, t is the thickness of attenuator, and E is the beam energy. The depth x should be zero for kilovoltage beams and dmax for megavoltage beams. Unfortunately, x is limited by the window thickness which is the core of this study. A Farmer-type cylindrical ion chamber and three parallel plate ion chambers (Capintec, PS-033; Markus; and Holt) were used to measure BBA for kilovoltage beams from a Siemens Stabilipan unit. Results indicate that attenuation is strongly dependent on the window thickness. For the 240 kVp beam, the thickness of lead for 5% and 1% transmissions are 3.1 mm, and 5.2 mm, respectively, with the Capintec chamber. The corresponding values of lead thickness for the Markus chamber are 2.3 mm and 4.0 mm; for the Holt chamber the values are 1.1 mm and 2.2 mm; and for the cylindrical chambers the values are 1.1 mm and 2.3 mm, respectively. Similar variabilities in lead thickness with ion chambers were also noted for the other kilovoltage beams. The large differences in lead thicknesses produce enormous clinical errors, especially for shielding eye and other critical structures. For small thickness of lead (< 0.1 mm), a 20-fold increase in surface dose could be observed instead of usual beam attenuation. This is due to intense low energy photoelectrons liberated from lead sheets in the contact with tissue. It is concluded that the lead thickness required to shield normal tissue varies with ion chamber. Until national or international guidelines for broad beam transmission measurements are established, the shielding materials in contact with skin should be coated with a thin (> or = 0.3 mm) low atomic number medium. In such a situation, transmission measurements will be independent of the choice of an ion chamber.     

弧齿锥齿轮在φ2.2M圆锥破碎机的应用

φ2.2M弹簧圆锥破碎机传动轴部的传动齿轮为直齿锥齿轮传动,相互啮合的轮齿是线接触,由于齿轮制造,安装的误差以及传动时的变形,容易产生仅轮齿一端接触的现象,从而引起载荷集中,传动不平稳,承载能力低,传动效率也比较低,容易产生断齿等现象.通过改造直齿锥齿轮传动为格里森弧齿锥齿轮传动,提高齿轮的重合度,从而增大了接触比,减轻了冲击,使传动更平稳,并且降低了噪音:负荷比压降低,磨损较均匀,相应增大了齿轮的负载能力,使用寿命更长:并且可以进行齿面的研磨,以降低噪音,改善接触区和提高齿面光洁度.     

Fracture of metals during pulsed loading

Experimental modeling of the dynamic fracture of a metal caused by a flyer plate of finite sizes revealed the formation of a channel-like crack under the contact zone as a result of the focusing of side rarefaction waves. The system of coaxial cylindrical cracks that sequentially form around the channel-like crack also has a spall nature of fracture and is localized at the sites of interference of rarefaction waves.     

Upsetting of a cylindrical blank by conical and flat dies. Part 1

The plastic flows of metal for the light stages in the upsetting of a cylindrical blank by conical and flat dies are considered. The position of the flows division is established at the boundary of two free surfaces at the end of the blank: the internal (conical) surface; and the external (lateral) surface. We may identify phenomenological aspects of the upsetting of a cylindrical blank by conical and flat dies: the direction of the displaced-metal flows; the curvature of the trajectory; the transition from sections that have no contact with the tool to end sections of the blank’s surface; the alternating rotation of the primary axes of the coordinate-grid cells; and the deformational rotation and shear near the end. The deformation due to the conical and flat dies is found to be superior to that associated with decrease in the contact friction and with the conversion of braking frictional forces to active forces. The theoretical conclusions are based on analysis of the same coordinate grid within the billet on the basis of nine photographs in step-by-step upsetting.     

Monoclonal antibody anti-type I and anti-zebrin II labelling in siluriform fishes: the role of shared lineage versus shared function in polypeptide co-distributions

Vibroarthrography (VAG) is an innovative, objective, non-invasive technique for obtaining diagnostic information concerning the articular cartilage of a joint. Knee VAG signals can be detected using a contact sensor over the skin surface of the knee joint during knee movement such as flexion and/or extension. These measured signals, however, contain significant interference caused by muscle contraction that is required for knee movement. Quality improvement of VAG signals is an important subject, and crucial in computer-aided diagnosis of cartilage pathology. While simple frequency domain high-pass (or band-pass) filtering could be used for minimizing muscle contraction interference (MCI), it could eliminate possible overlapping spectral components of the VAG signals. In this work, an adaptive MCI cancellation technique is presented as an alternative technique for filtering VAG signals. Methods of measuring the VAG and reference signals (MCI) are described, with details on MCI identification, characterization, and step size optimization for the adaptive filter. The performance of the method is evaluated by simulated signals as well as signals obtained from human subjects under isotonic contraction.     

钢中非金属夹杂物形态对其去除行为的影响

采用物理模拟手段研究球形、立方体、圆柱体、树枝状、团簇状等钢中常见形状夹杂物形状修正系数的差异性,并分析粒子表面形貌和运动取向对形状修正系数的影响.粒子的形状修正系数与阻力系数满足线性正相关,可以用形状修正系数评价粒子的上浮去除能力;在体积相同情况下,同类型夹杂物粒子的去除能力依次为树枝状(垂直)<粗糙球形<立方体<圆柱(半经6 mm)<圆柱(半经4 mm)<树枝状(水平)<团簇状(水平)<光滑球形;粗糙表面的球形其表面积约为光滑球形的2倍,其形状修正系数同时增加2.1倍.简单粒子的形状修正系数受运动取向影响较小,复杂粒子则受运动取向影响较大,树枝状颗粒垂直上浮时的形状修正系数约为水平上浮时的2倍.