低噪声密封轴承润滑脂选用及机理分析(续前)

2．2 典型低噪声密封轴承润滑脂的流变性和胶体性能 使用动态离心分油试验机、表观粘度试验机、流动压力测试仪和电子扫描显微镜等试验装置对选定的润滑脂进行试验分析。从众多的润滑脂噪声试验研究中，标定润滑脂流变性和胶体安定性的下列试验数据对轴承的振动性能产生重要的影     

我国滚动轴承润滑脂现状与发展（上）

众所周知，润滑脂的性能优劣对轴承的使用寿命有很大影响，在目前中国的市场上，用于滚动轴承的润滑脂名目繁多，各种润滑脂的性能各有特点，本文对中国轴承行业主要使用的密封轴承润滑脂现状进行了评述，并在此基础上利用动态离心分油试验机、     

润滑脂的动态分油能力对轴承振动性能的影响

采用离心分油试验机和滚筒试验机在不同温度下对润滑脂进行剪切和动态分油性能试验。采用振动仪测定不同状态的润滑脂对轴承振动的影响，对试验结果的分析表明：润滑脂进入接触区的难易程度是影响振动性能的主要因素，良好的动态分油能力和适度的皂纤维尺寸可缓解轴承中的贫油状态。     

基于BeQuiet+试验机的精密轴承润滑脂噪声性能评价方法

随着轴承制造技术的不断进步,润滑脂成为影响精密轴承噪声性能的重要因素。针对轴承运行的不同阶段,利用BeQuiet+试验机对轴承启动阶段润滑脂的噪声值、轴承运行阶段润滑脂的噪声等级、中频段及高频段的振动值和阻尼值进行测试,并与S0910-Ⅲ轴承振动测定仪的测试结果进行比较,发现对于噪声性能相差较大的润滑脂,两者测试结果具有很好的对应性,而对噪声性能相差较小的润滑脂,BeQuiet+试验机法有更好的区分性。利用BeQuiet+试验机建立精密轴承润滑脂噪声性能的评价方法,使用6种不同杂质粒子和微观形貌的润滑脂对该评价方法进行了验证。该评价方法重点关注轴承整个运行阶段的噪声性能以及运行过程中噪声的稳定性,能够较好地区分精密轴承润滑脂的噪声性能。     

我国滚动轴承润滑脂现状与发展（下）

在研究中我们选择了几种国内密封轴承生产公司常用的润滑脂，分别对之进行表观粘度、离心分油和其他一般理化指标的化验，然后使用速度型BVT-1A轴承振动测量仪、BANT轴承异音分析仪及加速度型S0910-1轴承振动测量仪进行分析(我们选择的几种数据都为联合国援助杭州轴承试验研究中心国家检测实验室(CNAL NO．L0309)和燕化集团天津润滑油脂有限公司共同合作的硕士研究生论文研究项目得到的数据，     

润滑脂流变性对滚动轴承振动性能的影响

采用表观粘度仪和振动仪研究了润滑脂的流变性对轴承振动性能的影响.研究发现,润滑脂在一定剪切速度下的表观粘度偏低对轴承振动性能有利,但润滑脂的表观粘度非常小时,在加工精度较差的中大型轴承上振动噪声性能反而不够理想;润滑脂的流变性能对中小型轴承振动噪声的影响有决定性作用,对微小型轴承的振动性能影响不明显,这符合摩擦学行为系统依赖性的规律.     

基于BP神经网络的电机轴承润滑脂含量判定方法

传统电机轴承润滑脂含量判定方法通过停转进行润滑脂含量测量,这种方法使用起来极其不便利,而且很多轴承的润滑脂都是密封的。针对其停转、拆封的不便,提出了一种基于BP神经网络的电机轴承润滑脂含量判定方法。利用采集到的电机轴承的振动数据,对其进行统计特征提取,通过BP神经网络来构建润滑脂含量与统计特征之间的函数关系。经试验验证,该方法可以有效地检测出电机轴承润滑脂含量,对电机轴承的维修保护有着重要意义。     

高速轴密封的结构

机床高速轴的密封，有多种形式。如果高速轴轴承采用油液润滑，则传统的接触式和非接触式密封方式，都有一定程度的渗漏，密封效果不太好。 笔者提出了一种在专用机床上的动力头主轴新型结构，其密封的结构形式与装配关系如图所示。 主轴是通过前后端的 46200、 46300角接触球轴承支承，而在主轴最前端选用了一个 180000型向心球轴承，轴承内外圈与轴颈和壳体孔结合处各有“ O”型密封圈密封，由于 180000型轴承本身两端带密封圈，不但可以密封轴承内部的润滑脂，使润滑脂泄漏不出去，而且还可以挡住外部油液，使油液不能通过轴承内外圈之…     

硬盘驱动器(HDD)主轴轴承

从性能要求、尺寸、密封、润滑等各方面介绍了硬盘驱动器主轴轴承的特点及改进。通过试验证明，使用塑料保持架的轴承噪声变化和振动性能较好；同时对几种润滑脂作了对比分析。     

低噪声润滑脂试验分析

将ＣＧ－２、ＭＰ－ＤＸ脂和汉沽脂作了密封轴承振动对比试验。试验结果表明，汉沽脂可使轴承振动值普遍降低，平均降低３．９～９．２ｄＢ，大大优于另两种润滑脂。附表３个。     

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.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

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。     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

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...