弧齿锥齿轮螺旋变性展成法切齿原理与仿真分析

传统加工方法加工弧齿锥齿轮副会使其接触区呈现对角线接触的不良现象,针对该现象,提出一种新型螺旋锥齿轮加工方法——螺旋变性展成法。为揭示螺旋变性展成法的切齿原理,根据机床、刀具和工件间的运动位置关系,以微分几何和齿轮啮合原理为基础,运用矢量分析法,以齿面中点为计算点建立切齿数学模型,分析推导机床调整参数计算公式;以一对弧齿锥齿轮为例进行了几何参数、刀具参数及机床调整参数的计算,建立弧齿锥齿轮三维虚拟仿真加工模型并进行齿面接触分析;最后,基于以上参数在数控铣齿机上进行切齿试验,齿面接触分析与滚检试验结果说明了螺旋变性展成法消除对角线接触的有效性。     

螺旋变性展成法加工锥齿轮副的建模与仿真分析

针对螺旋锥齿轮副接触区呈现对角线接触的传统加工,提出了一种新型的螺旋锥齿轮加工方法-螺旋变性展成法。该方法大轮采用展成法加工,小轮采用螺旋变性法加工。给出了刀具和工件的加工运动关系,利用齿轮啮合原理,分别建立了加工大轮和小轮的刀盘切削面方程及啮合方程。并由此获得大轮和小轮的齿面方程。依据齿面方程分别构建了齿轮副的三维模型,并进行啮合仿真分析。分析结果表明,使用螺旋变性展成法加工螺旋锥齿轮副可以从理论上避免接触区呈对角线接触的现象。     

螺旋锥齿轮的接触区及切齿机床的选用问题

螺旋锥齿轮副的接触区和齿面接触分析运动曲线是螺旋锥齿轮副重要的质量指标,影响螺旋锥齿轮的强度、寿命和啮合噪声。如何选用切齿机床和大、小轮的切齿方法以获得理想的接触区和齿面接触分析运动曲线是值得我们螺旋锥齿轮制造者关注的问题。     

弧齿锥齿轮双重螺旋法切齿原理及齿面接触分析研究

弧齿锥齿轮双重螺旋法具有高效、可实现干切削的特点,是Gleason制弧齿锥齿轮的先进加工方法。为揭示双重螺旋法的切齿原理,以大轮成形法加工的弧齿锥齿轮双重螺旋法为研究对象,以啮合原理和微分几何学为基础,根据刀盘、机床、工件之间的运动位置关系,利用矢量法、基于齿面3个参考点建立切齿数学模型,推导机床调整参数的计算过程;然后,以齿槽中点作为参考点,修正弧齿锥齿轮副的齿坯几何参数;另外,以小轮产形面方程代替其共轭齿面方程,提出新的齿面失配设计新方法,与传统方法相比简化计算过程。以一对7×43的准双曲面齿轮副为例进行设计计算和切齿加工,齿面接触分析与滚动检查结果验证所提出的双重螺旋法切齿原理的正确性,并根据该切齿原理开发弧齿锥齿轮双重螺旋法的设计软件,为该方法在国内的推广提供理论基础与技术支撑。     

基于螺旋锥齿轮切齿工序误差分析

对影响螺旋锥齿轮制造加工精度的重要因素——切齿工序误差进行了分析,提出了齿面接触区误差、齿距误差、齿面粗糙度误差修正方案,并指出切齿工序误差对齿轮噪音有严重影响。     

接触区偏移对螺旋锥齿轮齿根弯曲强度的影响

采用强度公式分析螺旋锥齿轮齿面接触区偏移对其啮合传动的齿根弯曲强度的影响;研究齿面接触区偏移的螺旋锥齿轮切齿调整参数计算方法;建立螺旋锥齿轮接触区偏移的动态接触有限元模型,利用有限元分析软件Abaqus计算接触区偏移的螺旋锥齿轮动态啮合齿根弯曲应力。计算结果表明为提高螺旋锥齿轮齿根弯曲强度性能,在轻载情况下,正车面接触区位于齿面中部较好;在重载情况下,正车面接触区应适量偏向小端;无论轻载还是重载情况下,倒车面接触区应适量偏向大端。     

双重螺旋法切齿参数对螺旋锥齿轮啮合特性的影响

针对螺旋锥齿轮双重螺旋法加工,考虑切齿参数误差,采用齿面接触分析方法,以双重螺旋法加工的(8×43)准双曲线齿轮副为例,分析了切齿参数对凹凸两齿面啮合特性(接触迹位置、传动误差及瞬时接触椭圆特征)的影响,获得了齿面接触位置对切齿参数误差敏感性特征。结果表明:滚比对接触迹位置的影响最大,正向滚比误差使得接触印痕向轮齿的大端以及齿顶方向移动,造成齿根附近潜在接触区增大;而径向刀位对齿长方向的影响较大,刀具齿形角在齿高方向的影响较为明显,角向刀位对接触迹位置则几乎没有影响。     

有误差的螺旋锥齿轮传动接触分析

以多体系统误差建模理论和齿轮啮合原理为基础,提出含有机床运动几何误差以及齿轮副安装误差的螺旋锥齿轮齿面接触分析(Error tooth contact analysis, ETCA)方法。以SGM法(大轮展成法加工,小轮变形法加工)加工的弧齿锥齿轮为例,通过ETCA分析,得到机床运动误差和安装误差对螺旋锥齿轮齿面加工质量影响的定量关系,对ETCA和TCA的结果进行对比分析,结果表明机床运动误差和安装误差对螺旋锥齿轮的齿面接触质量有较大的影响,为了通过齿面接触分析达到更准确的反调加工参数的目的,采用ETCA的分析结果指导加工参数反调更为合理。     

螺旋锥齿轮的齿面接触

螺旋锥齿轮齿面接触精度是影响螺旋锥齿轮副啮合质量最重要的质量环节。因此。螺旋锥齿轮的齿形设计、计算和加工的质量和精度对螺旋锥齿轮副起至关重要的作用。本文将从螺旋锥齿轮的切齿原理、计算理论基础、齿面接触修正等方面一一分析。     

螺旋锥齿轮批量加工通配方法的研究

分析了螺旋锥齿轮通配中存在的关键理论和技术问题,利用齿轮设计分析软件对基本加工参数进行设计计算和齿面接触TCA分析,利用CNC齿轮测量中心对加工后的齿轮进行齿面误差测量并进行反调和修正.通过切齿试验结果表明:经过测量和反调,所加工的齿轮与标准理论齿轮基本一致,滚检后的接触区与理论仿真接触区也基本吻合,齿轮副可以进行互换,为螺旋锥齿轮批量加工的通配问题提供了一种解决途径.     

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.