梳形铣刀的多线磨加工

齿杆梳形铣刀是用于加工油泵调速齿杆梳形齿条的刀具,刀具齿形精度要求高,见图1。从铣刀加工工艺过程可知,铲磨是决定该铣刀精度的关键。原采用单线砂轮磨削铣刀齿形如图2。第一圈齿磨完后,将砂轮架移动一个齿距,磨削第二圈齿,这样连续往复多次进行磨削,直到齿距和齿深都达到图纸要求。由于机床上齿轮、丝杠的传动误差、拖板的进给系统误差和磨头部分轴向窜动及径向跳动误差等都会直接影响齿距和齿深精度,虽然在加     

碗形工件通用磨夹具

图示夹具是用于磨削柴油机涡流室镶块外圆的。固定顶尖1和顶尖体8分别安装在头架和尾架顶尖孔中,顶尖体8上安装单列向心轴承101、103和单列推力球轴承8103。垫圈10可防止轴承101轴向窜动。工件装上夹具后,调整尾架内弹簧顶紧力。     

喷油泵总成凸轮轴轴向窜动间隙检测调整装置的应用

喷油泵总成中凸轮轴轴向窜动间隙是影响喷油泵总成性能的关键因素之一,因此,必须合理检测凸轮轴轴向窜动间隙的大小,为正确判断提供科学依据.经过大量的分析研究和工艺试验,设计了两套检测装置,通过两者组合使用,可以完成凸轮轴轴向窜动间隙大小的检测与调整,被广泛用于装配线上工序质量控制.     

中心孔磨床的磨轴结构改进

磨削中心孔的磨轴需要很高的转速和精度,我厂生产的系列中心孔磨床的磨轴最高转速达45000r／min,轴端的轴向窜动和径向跳动皆为0．002mm,所以磨轴的装配和加工都有很大的难度。最初小皮带轮和砂轮轴的联接采用图a所示结构,两者之间通过月牙键传递扭矩,轴向用螺母顶紧。砂轮轴是磨轴的关键零件,精度高、工序多,提高砂轮轴的成品率对磨轴的加工装配很关键。由于砂轮轴的轴径较小,只有机：状gmm,轴上键槽的对称度很难保证,键槽铣过后再磨削外圆,则外圆尺寸不易控制。热处理时,在键槽附近易产生微裂纹,试车时常常在此处断裂,因而…     

顶拉—支承磨削法

用顶拉-支承法磨削长轴套(如钻床的齿条套简、内圆磨具的套简、镗床的空心主轴)两端内孔,是近年来用得最广的一种方法。本文着重讨论磨削精度分析及误差补偿。图1是利用这种磨削方法磨削T611镗床空心主轴的情形。工件1的左端由不旋转的死顶尖2支承,两个弹簧3装在螺钉5杆部压向夹板,把工件压紧到顶尖2上,使其不能轴向窜动,右端支持在中心架6的两个下部可调卡爪上(上部那个卡爪不用)。     

螺杆轴向窜动误差分析

螺杆轴向窜动误差是影响螺旋传动精度的重要因素之一,螺杆轴向窜动误差呈周期性变化.最大的轴向窜动误差计算公式为△max＝Dtanamin,对于αmin为什么取最小者,文献资料上并没有具体分析,针对此问题分三种情况展开分析了螺杆轴肩端面、轴承止推面的形位误差对螺旋传动精度的影响,进一步完善了最大轴向窜动误差的理论计算公式.     

增加辅助装置提高加工精度

生产中，我们经常遇到许多节状材料需要加工，由于原材料表面易有锈蚀，加工中往往受顶尖的轴向顶紧力，使原材料向卡盘方向窜动，车出的工件加工长度易小于实际要求的长度。有时顶不紧原材料还会匕出撞伤操作者。为解决这些问题，我们可以在卡盘主轴心孔内增加顶丝辅助装置。     

F3精轧减速机高速轴轴窜分析

介绍承钢1780 mm精轧机F3减速机高速轴的轴窜问题,通过对轧制过程中高速轴的受力分析,结合现场检测,找出导致减速机高速轴发生窜动现象的原因,提出了具体改进措施,有效解决了轴向窜动现象,防止出现重大设备事故。     

汽车车轮形状误差的测量和分析

介绍了汽车车轮径向跳动和轴向窜动误差的测量原理和数据处理方法。由计算机控制的半自动测量台,测量及数据处理速度快,精度高,系统性能稳定。     

S3030/5M导轨磨床的结构分析(二)

四、磨头结构和进给传动结构 要实现高精度的磨削除具有运动平稳、精度高的工作台外,磨头及进给机构还应具备以下6个特点: 1.磨轴具有较高的径向和轴向精度 该磨床装有卧式磨头(图8、11)和立式万能磨头两种。 主轴装砂轮的锥径部的径向跳动为3μm,轴向窜动2μm,主轴安装轴承的轴颈跨距≈600mm,由于两轴径轴承自身回转误差形成的回转轴线,与主轴中心线成比例误差;主轴锥颈部与前轴承之间的距离较小于与支承主轴两端的轴承之间的距离,从而保证了锥颈的径向跳动,轴向精度靠两对轴向推力轴承保证。主轴组件装在套筒内,然后再装入壳体内,这给加工…     

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.