盾构轴承滚道的中频淬火工艺

盾构主轴轴承特殊的工作条件决定其必须具有极高的可靠性,轴承滚道中频淬火的硬度和硬化层深度是决定其是否具有高可靠性的重要指标之一。为了使盾构主轴轴承滚道的中频淬火质量满足较高的技术要求,采用样圈进行了大量的中频淬火工艺试验,通过试验验证,给出了盾构主轴轴承滚道中频淬火工艺及工艺参数。     

硬质合金钻头在淬火件中的应用

大型轴承的试验主轴吊装丝孔在试验装置中作用是十分重要的,它关系到轴承试验后如何安全拆卸。因此,试件淬火前遗漏的加工问题在淬火后用常规的加工方法是无法解决的,而硬质合金钻头在淬火件中起到其独特的作用。     

盾构轴承套圈齿部淬火工艺研究

盾构主轴轴承齿面和齿根中频淬火的硬度、硬化层深度是决定其是否具有高可靠性的重要指标之一,为了使盾构主轴轴承齿面和齿根的淬火质量满足技术要求,对其中频淬火时采用感应器的结构以及中频淬火工艺参数进行了研究。介绍了盾构主轴轴承齿面和齿根中频淬火工艺试验所用感应器的结构、试验工艺参数以及试验后的检验结果。     

42CrMoA风电主轴热处理工艺

正风电主轴为大型锻件,热处理工艺为调质,工件淬火出炉后采用不同的淬火冷却介质及淬火冷却时间来满足生产使用要求。淬火是热处理工艺中的重要工序,为保证大型锻件足够深的淬硬层来满足轴向性能及切向性能,整个工件截面必须有合理的温度梯度分布,也可减小淬火过程中的应力。42CrMoA风电主轴的热处理工艺有很多可参考,但是并不是照搬就可以满足所有产品的性能要求,为此我们再一次对其进行了分析和研究,通过不断调整参     

大兆瓦风电主轴双列圆锥滚子轴承的承载接触机理

在风力发电机组弹性接触承载数值分析平台的基础上,建立了风电主轴双列圆锥滚子轴承的全尺寸接触模型,并用于研究给定工况下的3MW风电主轴轴承承载接触机理.在径向载荷条件下,比较了风电轴承接触载荷有限元结果与赫兹理论计算结果,从而验证了数值模型分析的合理性;在此模型的基础上,研究了倾覆力矩对风电轴承接触载荷分布的影响规律以及极限工况下的轴承接触载荷与变形分布;最后,分析了轴承轴向游隙变化对轴承承载接触载荷的影响.通过研究发现,给定工况条件下,轴向游隙负向增大时,最大接触载荷变大,轴向游隙正向增大时,受载的滚子变少,轴承最大接触载荷不断增大.风电主轴双列圆锥滚子轴承承载接触机理研究可为大兆瓦风电轴承柔性设计技术提供理论依据.     

模块化轴承系统

<正> NKE公司为风电增速机行星齿轮开发了一个模块化轴承系统,使所用的轴承得以标准化,减少了零部件种类,同时简化了物流管理。奥地利NKE公司为风电增速机行星齿轮开发了一个模块化轴承系统。这种新型轴承系统使所用的轴承得以标准化,减少了零部件种类,简化了物流管理。该系统已在德国某著名变速箱生产厂的1.5MW、2MW和2.5MW风电增速机中应用。大多数风机通过增速机将相对较低的主轴旋转速度提高为发电所     

大型风电机组主轴轴承压紧工艺探讨

随着风电产业的日益发展,风电机组的功率呈现增长趋势。风机传动链的结构改变,选用的主轴轴承结构也有所变化。以往在主轴支撑结构中使用较多的调心滚子轴承正在逐渐地被圆锥滚子轴承方案所取代。本文主要介绍了某型风电机组圆锥滚子主轴轴承的装配工艺、安装要求,以及采用的轴承压紧3种方案的优缺点分析比较,为该结构主轴轴承装配工艺提供了参考。     

舍弗勒助推华锐进军海上风电

由华锐风电自主研发的中国首台海上6MW风力发电机组,日前在江苏省射阳县临港产业区完成吊装,该机组是国内目前实现吊装的最大兆瓦级风电机组。舍弗勒集团作为主轴轴承和变桨轴承供应商,全程参与了相关轴承组件的开发与供货。     

不同工况下风电机组主轴轴承动态特性研究

为获得风电机组主轴轴承在不同工况下的动态特性,以某汽轮厂1.5 MW风电机组为例,对主轴进行抽象简化,根据叶素理论推导出主轴轴承所承受的轴向载荷和径向载荷。利用UG软件建立主轴轴承模型,导入Adams中建立主轴轴承多刚体动力学模型,对三种不同工况下主轴轴承滚子与内圈、外圈、保持架的之间的相互作用进行分析。结果表明:在风机紧急刹车阶段,主轴轴承滚子与内圈、外圈、保持架的之间的相互作用力最大,转速突变阶段次之,启动至平稳阶段最小。     

新型静止式曲轴淬火工艺

1.目前存在的问题现在,大部分曲轴感应淬火机床在淬火时,曲轴需要旋转。“U”型感应器对每个连杆颈和主轴颈进行加热时,要求曲轴在围绕自身主轴旋转时,感应器应尽可能靠近连杆颈或主轴颈的轴承面,因为连杆颈相对主轴颈径向偏心,连杆颈会围绕主轴颈作旋转运动。曲轴的旋转速度各不相同,一般为24~32r/min。由于连杆颈相对主轴颈径向偏心,感应淬火机床的一些部件(包括电源的输出变压器,水冷感应器,铜排和电缆等),重量一般超过900kg,并且必须和曲轴一起在相同的轨道上作旋转运动。为保证如此笨重的系统的旋转轨迹的运行精度,需要配备一个特别的…     

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.     

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。     

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....     

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.