某型直升机行星齿轮机构弹流润滑研究

分析了某型直升机主减速器行星齿轮机构弹流润滑工况,研究了该齿轮系弹性润滑最薄弱啮合部位,计算得出了行星齿轮传动机构中齿宽、齿轮模数和压力角等齿轮参数对弹性润滑油膜厚度的影响,提出了改进直升机主减速器行星齿轮机械润滑状态的新思路和具体改进方案,结果证明增加行星轮和太阳轮的齿宽、模数和齿轮啮合角及提高润滑油粘度和粘压系数,可有效地改进齿轮润滑,减少齿面失效,提高行星齿轮传动机构的可靠性。     

圆弧齿行星减速器的效率计算

圆弧齿行星传动为一种K-H-V型行星传动,如图1所示。这种传动的行星轮a为一纯圆弧齿的外齿轮,与其相啮合的内齿轮b为一装有圆柱形针齿的针轮。由于内、外齿轮齿数相差较少(常为一齿差),故为一种新型少齿差传动。圆弧齿行星减速器的结构与目前广泛使用的摆线针轮行星减速器基本相同,其工作原理是依据长幅外摆线的形成原理而动作的。     

渐开线齿轮传动齿面滑动摩擦耗散功率研究

基于齿轮系统的功能传递原理和摩擦耗散机理,分析了齿轮传动过程中单齿和双齿啮合的特性,求解了齿面滑动速度和齿面法向正压力分配系数,建立了齿轮系统瞬时啮合耗散功率计算的数学模型,并以某NGW型行星齿轮减速器为例计算了组成系统的各对齿轮传动的瞬时摩擦耗散功率和传动效率。结果表明:单齿啮合区齿面滑动摩擦耗散功率较小,双齿啮合区齿面滑动摩擦耗散功率较大;齿面滑动摩擦耗散功率和啮合传动效率具有周期性和时变性,并且具有很大的突变性;外啮合齿轮副齿面摩擦耗散功率大于内啮合齿轮副;各行星轮和中心轮的啮合状态之间的相位关系对瞬时摩擦耗散功率和传动效率影响很大,对行星轮系传动的平稳性有一定影响。     

装载机驱动桥行星齿轮架磨损原因及改进措施

<正>1.故障现象某5t轮式装载机在使用过程中出现驱动桥轮边减速器异常发热现象。拆解检查后发现,齿轮传动系统运转良好,磨损量不大,但是轮边减速器的行星齿轮架磨损严重,行星齿轮侧面的垫片已完全陷入行星齿轮架内。齿轮油变质发黑,行星齿轮架磨损情况如图1所示。2.行星齿轮架结构该装载机采用整体式驱动桥,具有2级减速装置。驱动桥中间为采用圆锥齿轮主减速器,主减速器内设有采用圆锥齿轮的差速器。轮边减速器采用直齿行星齿轮减速器。该驱动桥具有结构     

大型行星齿轮减速器疲劳损坏原因分析及解决方案

行星齿轮已广泛应用于舰船、汽车、建材等领域。针对大型行星齿轮减速器行星结构,从微观方面分析了现有设计理论存在的局限,并对长期运转后疲劳损坏情况进行了原因分析:行星齿面因长期受力不均衡,齿面长期运转后易产生微裂纹。利用有限元分析了行星结构壁厚对齿轮齿根应力的影响,并提出了从优化结构设计到提高加工制造精度等多方面提高大型行星齿轮减速器可靠性的解决方案。     

含有直廓内齿轮行星轮系的传动误差计算与噪声试验

针对硬齿面内齿轮渗碳淬火后难于实现磨削的现状,提出以易于成形磨削的直线齿廓代替渐开线齿廓的方法。建立行星轮系齿轮的几何模型,利用齿面接触分析技术、承载接触分析技术和行星轮相位差的概念计算行星轮系传动误差。在不同转速和载荷下对渐开线内齿轮行星减速器和直廓内齿轮行星减速器进行噪声对比试验。传动误差计算和噪声试验均表明,在一定载荷条件下,直廓内齿轮行星轮系代替渐开线内齿轮行星轮系在工业上是完全可行的。     

RV减速器基于装配条件的配齿方法研究

RV减速器传统配齿方法受到中心轮齿数必须为行星轮数目整数倍的装配条件限制。从行星轮加工的角度分析提出了齿轮加工转角公式,该公式克服了装配条件的限制,以CSRV-160E-171型减速器为例对传统配齿方案进行了改进。对比了两种配齿方案的结果,结果证实采用新型配齿方案选出的最佳齿数组合能够减小减速器整机体积,同时提高了传动效率和输出转矩。进行了虚拟样机装配验证及Pro/E运动学仿真,结果表明齿轮加工转角公式与新型配齿方案的正确性。     

NN型渐开线少齿差行星减速器承载能力实验及齿轮修形方法研究

针对NN型渐开线少齿差行星减速器的承载能力问题,在减速器载荷实验台上进行了样机承载能力的实验研究。该减速器传动系统中的双联齿轮偏载现象严重,为了改善双联齿轮的承载情况,首先,使用齿轮修形方法进行了双联齿轮的齿面修形和载荷虚拟仿真分析,降低了双联齿轮齿面的单位长度载荷,改善了双联齿轮的齿面载荷分布不均和齿面接触斑位置,并提高了双联齿轮的传动精度;然后,制造了齿轮修形后的样机;最后,在减速器载荷实验台上进行了样机承载能力的实验。研究结果表明:修形前该减速器具有很高的承载能力,但其传动系统中的双联齿轮偏载现象严重;在相同的实验条件下,齿轮修形后齿面接触斑位置居于齿面中心,齿面无磨损,改善了齿面载荷分布情况,降低了齿面的载荷,提高了减速器的承载能力。     

电动车轮毂电机行星齿轮减速器均载性能分析

针对轮毂电机中浮动式行星齿轮减速器建立了浮动行星齿轮传动系统的动力学方程,并推导了均载系数的计算公式。利用ADAMS对太阳轮和内齿圈与各行星轮之间的动态接触力进行仿真,并对比分析了不同浮动结构类型对行星齿轮系统内外啮合副的均载性能的影响。仿真结果表明,双浮动类型行星齿轮系统的行星轮啮合力分布更均匀,运行过程中较少出现波动和突变;其均载系数最小,均载性能明显优于无浮动和单浮动结构的行星齿轮;研究结果为行星齿轮减速器的选型及其均载设计提供支持。     

基于ANSYS对EBZ260掘进机减速器结构强度的分析研究

根据掘进机结构和性能参数的要求,以EBZ260型掘进机减速器为研究对象,建立行星减速器有限元分析模型,在仅考虑切向作用载荷情况下,计算了心轴、行星轮、内齿圈的应力分布情况.根据计算的结果可知减速器最大应力为449.6 MPa,最大变形量0.091 9 mm,最后对行星轮提出优化改进方案,研究对提高设备使用寿命具有重要意义,对减速器结构强度的研究具有积极参考价值.     

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.