轴承径向游隙自动测量装置的设计与精度分析

针对目前轴承径向游隙检测过程中,人工手动检测效率低、精度差等问题,采用超高精度的激光传感器,研制了一种新的轴承径向游隙自动测量装置。通过测试条件的设计、数据的采集与处理,对装置的测量不确定度进行了分析,并与超高精度Mahr测长仪进行了比对测量。研究结果表明:该装置实现了对轴承径向游隙的自动检测,满足测量的精度要求。     

基于共振法的第三代轮毂轴承负游隙测量技术研究

针对第三代轮毂轴承负游隙难以直接测量的问题,基于Hertz接触理论推导出了第三代轮毂轴承载荷与变形的关系,构建了第三代轮毂轴承负游隙与轴向接触副共振频率的关系曲线;根据幅频特性曲线提出了测量轮毂轴承接触副固有频率的简化共振法模型并研制了第三代轮毂轴承负游隙在线测量仪。由激励器激励轮毂轴承使其产生共振,通过LabVIEW软件采集与分析轮毂轴承共振的特征频率,从而实现第三代轮毂轴承负游隙的在线测量。研究结果表明:第三代轮毂轴承负游隙与接触副共振频率之间存在一定的映射关系,测量值与理论计算值具有较好的一致性,能够满足第三代轮毂轴承负游隙在线测量的工业要求。     

轮毂轴承游隙设计方法研究北大核心

阐述了轮毂轴承游隙的概念,分析了第1代、第2代和第3代轮毂轴承的游隙影响因素,研究了轮毂轴承游隙的计算方法。在此基础上,形成了轮毂轴承游隙设计思路,并给出了轮毂轴承游隙测试验证方法,对指导轮毂轴承产品开发具有重要的意义。     

第三代轮毂轴承游隙的分析与检测

为解决第三代轮毂轴承负游隙难以直接获取的问题,将第三代轮毂轴承游隙的间接测量方法与角接触球轴承轴向载荷-位移关系相结合,开展了轮毂轴承游隙与预紧力的分析,建立了卸载力与预紧力之间的关系,提出了装配件和装车件状态下轮毂轴承游隙的计算方法;在利用加载机构模拟锁紧力的基础上,设计了一种能应用于三代驱动和非驱动轮毂轴承的游隙检测方法以获取轮毂轴承游隙.研究结果表明,第三代轮毂轴承的卸载力与预紧力之间存在线性关系,不同初始游隙的轴承在相同锁紧力矩下导致的轴向位移趋于一致.     

轮毂轴承游隙设计方法研究

阐述了轮毂轴承游隙的概念,分析了第1代、第2代和第3代轮毂轴承的游隙影响因素,研究了轮毂轴承游隙的计算方法。在此基础上,形成了轮毂轴承游隙设计思路,并给出了轮毂轴承游隙测试验证方法,对指导轮毂轴承产品开发具有重要的意义。     

一种新型轴承径向游隙检测与分选装置

研制了轴承径向游隙自动检测与分选装置,可实现自动送料、自动检测与自动分选。该装置机械结构包括送料机构、夹紧机构、顶旋机构和分选机构;控制系统以STC12c5a60S2单片机为核心,采用C语言编制控制程序;测量系统由激光传感器构成,以Lab VIEW编制显示界面,用于数据的采集、显示与分析。试验表明,研制的轴承径向游隙自动检测与分选装置能够快速精确地对轴承径向游隙进行检测与分选。     

第三代轮毂轴承负游隙的弹性变形检测方法

针对第三代轮毂轴承负游隙难以直接测量的问题,提出了一种间接测量负游隙的方法.基于赫兹接触理论建立了轮毂轴承负游隙与弹性变形量之间的映射关系,将负游隙的测量转换为零游隙样件弹性变形量与成品轴承弹性变形量的测量,从而实现第三代轮毂轴承负游隙的快速、简便测量.     

恩梯恩开发出有助于安全控制的3轴负荷传感器内置轮毂轴承

日本恩梯恩公司（NTN）日前开发出了嵌入3轴负荷检测用传感器的轮毂轴承。由于将传感器置于轮毂而非车身上,可提高控制的响应性及精度。因其是3轴检测,路面状况的推断精度得以提高;可准确控制车辆,使轮胎接地能力得以充分发挥。     

第3代轮毂轴承单元轴向游隙影响因素的正交试验

利用正交试验法分析沟位置差、径向游隙、配合过盈量及锁紧力矩等参数对轮毂轴承单元轴向游隙的影响,给出了沟位置差和径向游隙值的控制范围,可为第3代汽车轮毂轴承单元的装配及零配件工艺的优化提供数据支持。     

负游隙对轮毂轴承摩擦力矩的影响研究

通过大量研究发现,汽车轮毂轴承单元的负游隙对其摩擦力矩存在较大的影响。为了明确轮毂轴承负游隙对其摩擦力矩的具体影响,研究了汽车轮毂轴承摩擦力矩的计算方法,以某型号轮毂轴承为例,建立了轮毂轴承负游隙的接触理论模型,分析表明负游隙对钢球与内外圈滚道的接触载荷存在影响。设计了相关试验进一步探究负游隙对轮毂轴承摩擦力矩的关系,试验表明,负游隙对轮毂轴承的摩擦力矩存在较明显的影响,摩擦力矩的平均差值达到了0.2Nm,且随着负游隙绝对值的减小,摩擦力矩呈减小的趋势,这一结论可以为提升轮毂轴承的效率提供参考依据。     

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。     

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.     

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....     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.