典型精锻模设计实例：第二讲 心轴与磁极精锻模设计

（1）工艺分析 心轴的锻件图由美方直接给出,见图1,所用材料为20钢。图中未注拔模斜度为5°,未注圆角为R1mm,未注公差±0．5mm,角度公差±1°,错差≤0．3mm,残余飞边≤0．3mm,不允许有裂纹和毛刺。     

小批量倾斜小孔的钻削方法

对于单件或小批量制造时圆孔钻削的情况,往往划线后使用普通钻床加工。我们在实践中遇到如图1所示的倾斜小孔的加工,需要钻削20个均布的小孔Ф4．5mm。与基准A的夹角34．5°±0．5°和距中心的高度90．81mm是评价小孔精度的两个重要指标,尺寸73．69mm是通过角度34．5°±0．5°和高度90．81mm计算出的工艺尺寸。     

捷联式光学导引头的稳定、跟踪原理与系统仿真

为研究捷联式光学导引头在系统中的应用,建立了该类导引头的数学模型。应用力学与空间飞行原理,针对捷联式俯仰、方位双框架光学导引头特点,研究其稳定和跟踪工作原理。进行了空间视线的坐标描述与变换,建立了载体扰动下导引头光轴稳定条件和导航解算算法。在此基础上,根据气动弹性振动一阶振型,并结合导引头模型进行系统飞行仿真分析。结果表明：采用远程稳定捷联式导引头方案,在有、无气动弹性干扰下的视线角偏差分别为0．5°和0．005°,气动弹性的干扰使跟踪图像出现了抖动,导引头易丢失目标而无法实现跟踪功能;在一定视场条件下,通过对视线角速率的提取与低通滤波处理,有、无气动弹性干扰下输出的制导信号波动基本相同,末制导CEP约为1m。模型全面体现了捷联式导引头的稳定、跟踪原理以及噪声和干扰对其工作过程的影响。     

45°回转头体工艺计算的另一种解法

我厂XH7910／2型立、卧式加工中心集立式加工中心和卧式加工中心为一体,采用立、卧主轴转换结构,实现工件一次装夹的五面加工技术,结构比较紧凑。其中,立、卧回转头主轴箱体是该机床的主要零件,图1是主轴立、卧转换结构换示意图。图2是回转头体简图,其中45°、（375±0.05）mm及角度形位公差是非常重要的尺寸,加工起来也很困难,这些尺寸的加工精度直接影响着机床主轴的立、卧转换精度。为保证该零件45°夹角、（375±0．05）mm尺寸及其角度形位公差加工精度,我们安排在瑞士DiXi280高精度坐标镗床上加工。     

钢丝绳传动航空光电稳定平台设计

针对某高光谱相机选择系留气球作为飞行平台的使用要求,设计了一台钢丝绳传动两轴稳定平台,对系留气球在方位和俯仰方向的姿态变化进行角度补偿。稳定平台的方位和俯仰传动机构均采用钢丝绳传动,方位轴和俯仰轴的连续驱动力矩分别为93.6 N·m和117 N·m,两轴的最高转速分别为25(°)/s和20(°)/s。对稳定平台进行了实验室测试,测试结果表明:稳定平台的传动精度为5μrad,传动误差不大于0.7%,方位轴和俯仰轴的开环控制伺服带宽分别为15 Hz和35 Hz,正弦跟踪精度均方根误差值分别为0.0045和0.0043。然后进行了外场飞行试验,稳定平台安装在系留气球底部,俯仰框架上安装35 kg的高光谱相机进行空中对地观测,飞行试验中获取稳定平台陀螺稳定数据,得到方位轴和俯仰轴的稳定精度分别为38.83μrad(RMS)和37.26μrad,满足高光谱相机稳定成像的指标要求。     

XS5746数显万能滑枕升降台铣床主轴漏油的修理

1．机床概述 XS5746数显万能滑枕升降台铣床由于床身上部的滑枕结构采用横向进给,滑枕横向移动长度大于普通升降台铣床一倍以上。铣头由两个45°滑座组成,左右可转动360°,抬头低头可转动0-180°,可实现常规和高速切削,并兼有立、卧及万能铣的功能,适用范围广,可进行大批量产品的生产。     

球墨铸铁管接头铸造工艺的优化及应用

我公司生产的出口铸件——球墨铸铁管接头结构简单、品种型号多,有十余种口径尺寸,如三通（包括带螺纹三通、无螺纹三通）、二通（包括90°弯管、45°弯管、22．5°弯管和变径管等）,要求能够承受一定水压（1．2-1．5MPa）,厚度均匀（有6．5mm、6．9mm、7．1mm和12．1mm几种规格）,材质要求为QT450-10。     

DK7632精密数控低速走丝电火花线切割机

工作台面尺寸（长X宽X高）：720×480×220mm;工作台行程（X＊Y）：320x500mm;主轴行程（z）：210mm：U、V轴行程：±50mm;最大工件尺寸（长X宽X高）：900×670×210mm;最大加工厚度：210mm;最大切割锥度／工作厚度：30°／100mm：电极丝直径范围：015～0．3mm;电极丝张力：2—15N;电极丝运行速度：1—12m／min;最大工件重量：500kg;机床消耗功率：15KVA;     

喷水切割系统

据Jet Edge公司介绍，该公司生产的High Rail Gantry高精度喷水切割系统能够将任何材料制成复杂的部件，并且其稳定的高架设计使切割工具能够完全进入封闭工作区，并可抬高关键部件，以使其远离加工环境。该HighRaiIGantry能够使整个封闭工作区的精度达到0．005”，可重复性为0．001”。其2’增量可从4’×4’到24’×14’。客户可以根据自己的需求选择系统，且该系统扩能极为容易。据该公司称，     

面向稳定控制的小体积开环光纤陀螺设计

针对平台稳定、飞行控制等领域的应用特点,设计开发了一系列小体积、低成本、高可靠的开环光纤陀螺,以解决传统机电陀螺、半液浮速率陀螺所面临的响应频率低、寿命短、环境适应性差等问题。此种陀螺及陀螺组合已在导弹导引头稳定,飞行姿态控制等多领域获得成功应用。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.