微型配对轴承启动摩擦力矩的测量

针对微型配对轴承启动摩擦力矩测量比较困难的问题,在原有摩擦力矩测量仪的基础上,设计了加载螺栓以及定位轴,可实现微型配对轴承启动摩擦力矩的检测,经实际使用证明,该方法简单有效,而且测量结果准确可靠。     

低温下润滑剂对微型轴承启动摩擦力矩的影响

对于微型轴承启动摩擦力矩敏感的应用场合,测试润滑剂性能的影响十分重要,介绍了一种微型轴承低温启动摩擦力矩测试装置,其可根据要求改变轴向载荷,测试结果表明:该装置室温下与用YZC-II摩擦力矩测试仪测得的结果吻合;在不同的超低温下测试了几种润滑剂对微型轴承启动摩擦力矩的影响,测得的数据有较好的重复性。     

仪器轴承摩擦力矩检查仪试制成功

山东烟台轴承仪器厂于去年试制成功仪器轴承启动摩擦力矩,平均摩擦力矩和最大摩擦力矩检查仪,经山东省机械工业厅组织     

M992型微型轴承摩擦力矩测量仪的研制

本文分析了微型轴承摩擦力矩特性,提出了设计摩擦力矩测量仪的主导思想。对新研制的M992型测量仪作了介绍。仪器适用于测量内径2～8毫米、外径5～18毫米的向心球轴承和向心推力球轴承,被测轴承上可施加100～500克的轴向负荷,被测轴承可垂直或水平放置于仪器中。对构成仪器的机械部分和电气部分作了详细阐述。给出了微型轴承摩擦力矩影响因素的典型曲线。附图13幅、表8个,参考文献12种。     

讯号控制ДМП—_(20)~2摩擦力矩仪试制成功

微型仪器轴承的摩擦力矩值大小是考核产品质量的重大指标之一。现在普遍采用的一种凰Mn—_(20)~2摩擦力矩仪是:被测量的轴承,内圈套在仪器的心轴上,外圈套上一个带有摆杆的摆轮,当仪器的电机旋转时,通过轴承本身的摩擦带动了套在外圈上的摆轮的摆杆,根据轴承本身的摩擦力矩大小通过摆轮上的摆杆反映为仪器面板上角度的变化,即由角度大小来确定摩擦力矩值。其计算式为     

特殊结构低磨擦力矩微型轴承的加工

随着科学技术的发展,在一些特殊的应用领域对微型轴承的性能提出了更高的要求,为了满足主机的使用要求,许多新结构、新型号的轴承应运而生,相应的微型轴承的加工工艺也将引入一些非常规的方法以达到预期的目的。本文介绍一种特殊结构低摩擦力矩微型轴承的加工工艺。1　轴承的主要结构和指标图1所示是一种特殊结构的微型轴承。该轴承采用片状保持架,外圈与普通微型轴承类似,内圈为分离型的非对称双半圈结构,双半圈组合安装,配套使用,其中一个为带台阶的内圈,其高度仅为1.17mm。保持架安装在这个台阶上。轴承精度为P4级,启动摩擦力矩不大于0.…     

大型转盘轴承启动摩擦力矩的试验及分析

转盘轴承工况复杂、转速极低、承受载荷重。启动摩擦力矩往往大于理论计算值,为了确定轴承摩擦力矩的精确数值,分别测试不同轴向载荷状况下转盘轴承启动摩擦力矩,总结了转盘轴承的启动摩擦力矩随载荷大小变化的规律及关系,为轴承的设计及工艺方法提供试验数据。     

基于ADAMS的滚滑轴承摩擦力矩研究

针对在高速、重载的情况下轴承摩擦力矩较大,极容易发热和磨损,导致使用寿命大大降低的问题,基于轴承摩擦力矩测量原理建立了滚滑轴承的摩擦力矩数学模型,并以此为基础利用ADAMS软件建立了滚滑轴承的动力学仿真模型。考虑到摩擦力矩数值的波动性,对变化规律进行了分析,并给出了滚滑轴承启动摩擦力矩和动摩擦力矩在仿真试验中的提取方法;研究了不同径向载荷、转速、滚子与滑块之间的间隙和径向游隙对摩擦力矩的影响;借助SKF轴承摩擦力矩计算器,验证了仿真模型的正确性。研究结果表明:4种不同工况结构参数对滚滑轴承启动摩擦力矩和动摩擦力矩都有一定影响,该结果可为滚滑轴承降低摩擦力矩设计提供参考依据。     

陀螺框架轴承摩擦力矩分析

针对陀螺框架轴承要求启动摩擦力矩小而稳定的苛刻要求,建立轴承摩擦力矩分析模型,在已有的球与内外圈弹性滞后、差动、自旋、润滑影响因素引起的摩擦力矩分析基础上,重点考虑浪形及冠型保持架引起的摩擦力矩。求得的轴承启动、动态摩擦力矩与YZC-II测试仪测试结果吻合较好。分析表明,浪形保持架整体优于冠型保持架,保持架与球作用引起的摩擦力矩比例随轴向载荷减小而增大,该比重在启动过程中较大,在动态过程明显降低;通过对4种型号框架轴承不同转速的摩擦力矩分析,当转速低于2 r/min时,轴承摩擦力矩受转速影响不大,随着速度增大,启动速度对轴承启动摩擦力矩值、动态摩擦力矩波动范围影响突显出来。     

M992轴承摩擦力矩测量仪的改进

Ｍ992型轴承摩擦力矩测量仪(以下简称Ｍ992仪)用于测量微型轴承摩擦力矩的最大值和平均值,并可通过记录仪记录被测轴承摩擦力矩变化的轨迹。由于该仪器采用集成运放构成各单元电路,测量值的计算也采用模拟线路来完成,因此调整元件多,且因元件的寿命和精度等因素影响,使仪器故障率较高,常需专业人员对仪器进行调整、维修,这给仪器的使用带来很大的不便。1　改进方法为提高Ｍ992仪的稳定性、可靠性等功能,采用单片微型计算机对Ｍ992仪进行改进后,可完成轴承摩擦力矩测量过程的数据采样、模数转换、平均值和最大值的计算以及仪器机械转动部件(…     

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...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

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.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

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....     

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.