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摆线钢球传动的齿形综合研究 被引量:21
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作者 安子军 曲志刚 张荣贤 《机械工程学报》 EI CAS CSCD 北大核心 1996年第5期41-46,共6页
根据活齿传动理论,研究了摆线钢球传动的齿形形成和钢球运动原理,推出其理论、实际齿形综合方程和钢球运动位置方程,研究了齿形连续性及齿形参数选择。
关键词 摆线 钢球传动 齿形 综合 活齿传动
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水果品质机器视觉检测中的图像颜色变换模型 被引量:19
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作者 应义斌 付峰 《农业机械学报》 EI CAS CSCD 北大核心 2004年第1期85-89,共5页
在水果品质的机器视觉检测过程中 ,水果形状导致的图像颜色失真直接影响最终的检测和分级结果。本文在 6个位置分别采集了 3种大小、1 9种不同表面颜色的标准实验球体的图像。在分析球体的大小、表面颜色和图像采集位置等因素对球体图... 在水果品质的机器视觉检测过程中 ,水果形状导致的图像颜色失真直接影响最终的检测和分级结果。本文在 6个位置分别采集了 3种大小、1 9种不同表面颜色的标准实验球体的图像。在分析球体的大小、表面颜色和图像采集位置等因素对球体图像颜色的亮度、色调和饱和度的影响后发现 ,球体图像的颜色失真主要是颜色的亮度失真。建立了摄像视区中心球体图像的亮度校正模型 ,该模型的相关系数 R2 为 0 .84 6。采用该模型在Matlab软件平台上构建了柑桔图像的颜色校正算法 ,实验结果表明 。 展开更多
关键词 水果品质 机器视觉 检测技术 图像颜色变换模型 自动化分级技术
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摆线钢球行星传动啮合副非线性力学性能研究 被引量:25
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作者 张鹏 安子军 杨作梅 《工程力学》 EI CSCD 北大核心 2010年第3期186-192,共7页
摆线钢球啮合副为空间曲面啮合结构,啮合副承载与变形之间的非线性关系以及啮合副接触区扩展均会对其力学性能产生较大的影响。该文首先利用超静定方法建立了啮合副非线性力学模型,根据啮合力与阻力矩作功相等的原理推导出时变的啮合力... 摆线钢球啮合副为空间曲面啮合结构,啮合副承载与变形之间的非线性关系以及啮合副接触区扩展均会对其力学性能产生较大的影响。该文首先利用超静定方法建立了啮合副非线性力学模型,根据啮合力与阻力矩作功相等的原理推导出时变的啮合力函数。然后将啮合力转换为啮合接触区上的椭球状分布载荷,利用叠加法对接触区微元在集中力作用下的变形与应力结果进行积分,给出了接触区变形挠曲面方程、接触表面下各应力函数,以及最大切应力的深度位置。最后根据钢球位置方程,建立了啮合副不同啮合位置的有限元模型,对钢球与摆线槽的啮合过程进行了数值模拟,分析了啮合副应力分布状态以及啮合点等效应力的变化规律。结果表明:采用啮合副非线性力学模型和接触区分布载荷减少了线弹性和集中力简化处理造成的误差,为啮合副承载状态提供了更符合实际的计算结果。 展开更多
关键词 行星传动 非线性力学性能 赫兹接触 有限元 摆线 钢球 啮合副
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ANALYSIS OF MECHANICS IN BALL SPINNING OF THIN-WALLED TUBE 被引量:18
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作者 JIANG Shuyong REN Zhengyi 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2008年第1期25-30,共6页
Ball spinning is applied to manufacturing thin-walled tube with high precision and high mechanical properties. On the basis of plastic mechanics, by simplifying ball spinning of thin-walled tube as plane strain proble... Ball spinning is applied to manufacturing thin-walled tube with high precision and high mechanical properties. On the basis of plastic mechanics, by simplifying ball spinning of thin-walled tube as plane strain problem, slab method is used for the purpose of calculating the contact deformation pressure. The spinning force components, the torsional moment, the deformation power and the deformation work are calculated further as well. The influence of the two important process parameters such as the feed ratio and the ball diameter on the spinning force components is analyzed in order to further control the spinning force components by regulating the two process variables during the ball spinning process. The stress and strain state in deformable zone as well as mechanics boundary conditions in ball spinning are obtained. The effect of the three spinning force components on the formability of the spun part is analyzed and validated through the ball spinning experiments. The theoretical and experimental results show that the radial spinning component plays a significant role in ball spinning of thin-walled tube, and the mechanics situation in backward ball spinning contributes to enhancing the plasticity of the metal material, but that in forward ball spinning contributes to advancing the axial flow of the metal material. 展开更多
关键词 Power spinning Tube spinning ball spinning Spinning force Slab method
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A 5-DOF Model for Aeroengine Spindle Dual-rotor System Analysis 被引量:18
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作者 HU Qinghua DENG Sier TENG Hongfei 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2011年第2期224-234,共11页
This paper develops a five degrees of freedom(5-DOF) model for aeroengine spindle dual-rotor system dynamic analysis.In this system,the dual rotors are supported on two angular contact ball bearings and two deep gro... This paper develops a five degrees of freedom(5-DOF) model for aeroengine spindle dual-rotor system dynamic analysis.In this system,the dual rotors are supported on two angular contact ball bearings and two deep groove ball bearings,one of the latter-mentioned bearings works as the inter-shaft bearing.Driven by respective motors,the dual rotors have different co-rotating speeds.The proposed model mathematically formulates the nonlinear displacements,elastic deflections and contact forces of bearings with consideration of 5-DOF and coupling of dual rotors.The nonlinear equations of motions of dual rotors with 5-DOF are solved using Runge-Kutta-Fehlberg algorithm.In order to investigate the effect of the introduced 5-DOF and nonlinear dy-namic bearing model,we compare the proposed model with two models:the 3-DOF model of this system only considering three translational degrees of freedom(Gupta,1993,rotational freedom is neglected);the 5-DOF model where the deep groove ball bearings are simplified as linear elastic spring(Guskov,2007).The simulation results verify Gupta's prediction(1993) and show that the rotational freedom of rotors and nonlinear dynamic model of bearings have great effect on the system dynamic simula-tion.The quantitative results are given as well. 展开更多
关键词 AEROENGINE DUAL-ROTOR ball bearing nonlinear dynamics five degrees of freedom
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Quasi-static Analysis of Thrust-loaded Angular Contact Ball Bearings Part Ⅰ:Theoretical Formulation 被引量:16
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作者 CHEN Wenhua1,2,MA Zikui1,GAO Liang1,LI Xinglin3,and PAN Jun2 1 Institute of Mechanical Design,Zhejiang University,Hangzhou 310027,China 2 Institute of Mechanical Design and Manufacturing,Zhejiang Sci-Tech University,Hangzhou 310018,China 3 State Testing Laboratory of Hangzhou Bearing Test & Research Center,Hangzhou 310022,China 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第1期71-80,共10页
Ball bearings play an important role in various rotating machineries,but the complicated kinematic and tribological features of ball bearings make many aspects of their operating behaviors still inconclusive.Most theo... Ball bearings play an important role in various rotating machineries,but the complicated kinematic and tribological features of ball bearings make many aspects of their operating behaviors still inconclusive.Most theoretical analyses of ball bearings up to date are based on either the hypothesis of race control or other empirical models to determine the ball motion of ball bearings,but none of these strategies can reveal and consequently employ the intrinsic coupling mechanism between the spin and the tangential traction of contacting bodies rolling upon one another.To remedy the deficiency of current analytical models for ball bearing analysis,the rolling contact theory is employed to establish an explicit link between motions and interactions within ball bearings.A differential slip model is established to precisely define the slip component due to the significant curvature of the common contact patches between the ball and inner/outer raceways.The creepage and the spin ratio are formulated to accurately define the relative rigid motion between the ball and the inner/outer raceway.Then a quasi-static analytical model is established that can accurately determine the motions of the balls and races of the ball bearing.It can also give a vivid description of the slip and traction distributions within the contact area.The analytical model can be effectively used to analyze the operational conditions and tribological features of solid-lubricated ball bearings.It can also be used optimize the construction of ball bearings for specific applications. 展开更多
关键词 ball bearing QUASI-STATIC CREEPAGE differential slip tangential elastic compliance
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摆线钢球行星传动动力学建模与固有特性分析 被引量:17
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作者 张鹏 安子军 《中国机械工程》 EI CAS CSCD 北大核心 2014年第2期157-162,共6页
首先根据摆线钢球行星传动的受力状态,计入各啮合副之间的载荷分布及其变化规律,建立了摆线钢球行星传动系统的平移—扭转耦合动力学模型;然后通过分析各构件间的相对位移关系,推导出了系统动力学方程,进而通过求解其特征值得到相应派... 首先根据摆线钢球行星传动的受力状态,计入各啮合副之间的载荷分布及其变化规律,建立了摆线钢球行星传动系统的平移—扭转耦合动力学模型;然后通过分析各构件间的相对位移关系,推导出了系统动力学方程,进而通过求解其特征值得到相应派生系统的各阶固有频率和主振型,从而揭示了系统的固有特性;最后分析了摆线钢球行星传动的主要结构参数对固有频率的影响。 展开更多
关键词 行星传动 摆线 钢球 动力学模型 固有频率
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Convergence of Newton's Method and Uniqueness of the Solution of Equations in Banach SpacesⅡ 被引量:15
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作者 XingHuaWANG ChongLI 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2003年第2期405-412,共8页
Some results on convergence of Newton's method in Banach spaces are established under the assumption that the derivative of the operators satisfies the radius or center Lipschitz condition with a weak L average.
关键词 Nonlinear operator equation Newton's method Lipschitz condition with L average Convergence ball
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Microstructure and electrical properties of Y_2O_3-doped ZnO-based varistor ceramics prepared by high-energy ball milling 被引量:14
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作者 Hongyu Liu Xueming Ma +1 位作者 Dongmei Jiang Wangzhou Shi 《Journal of University of Science and Technology Beijing》 CSCD 2007年第3期266-270,共5页
Y2O3-doped ZnO-based varistor ceramics were prepared using high-energy ball milling (HEBM) and low-temperature sin- tering technique, with voltage-gradient of 1934-2197 V/mm, non-linear coefficients of 20.8-21.8, le... Y2O3-doped ZnO-based varistor ceramics were prepared using high-energy ball milling (HEBM) and low-temperature sin- tering technique, with voltage-gradient of 1934-2197 V/mm, non-linear coefficients of 20.8-21.8, leakage currents of 0.59-1.04 μA, and densities of 5.46-5.57 g/cm3. With increasing Y2O3 content, the voltage-gradient increases because of the decrease of ZnO grain size; the non-linear coefficient and the leakage current improve but the density decreases because of more porosity; the donor con- centration and density of interface states decrease, whereas the barrier height and width increase because of the acceptor effect of Y2O3 in varistor ceramics. 展开更多
关键词 inorganic materials electrical properties high-energy ball milling VARISTOR MICROSTRUCTURE low-temperature sintering zinc oxide yttrium oxide
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Enhanced mechanical properties and degradation rate of Mg-Ni-Y alloy by introducing LPSO phase for degradable fracturing ball applications 被引量:16
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作者 Jingfeng Wang Shiqing Gao +6 位作者 Xiuying Liu Xing Peng Kui Wang Shijie Liu Weiyan Jiang Shengfeng Guo Fusheng Pan 《Journal of Magnesium and Alloys》 SCIE 2020年第1期127-133,共7页
In this work,as-cast Mg-Ni-Y alloys were proposed to develop a feasible material for fracturing balls,and their mechanical performance and corrosion behavior were systematically investigated.Long period stacking order... In this work,as-cast Mg-Ni-Y alloys were proposed to develop a feasible material for fracturing balls,and their mechanical performance and corrosion behavior were systematically investigated.Long period stacking order(LPSO)phase was firstly introduced to improve both the mechanical properties and degradation rate of magnesium alloys.With the increase of LPSO phase,the compressive strength was improved significantly,while the elongation of the alloys decreased owing to the relatively brittle nature of LPSO phase.Due to the higher corrosion potential of LPSO phase,the LPSO phase can accelerate the corrosion process by providing more micro-couples.However,the LPSO phase would serve as the corrosion barrier between the corrosion medium and the matrix when the contents of LPSO phase are too high in Mg92.5Ni3Y4.5 and Mg87.5Ni5Y7.5 alloys.As-cast Mg97.5Ni1Y1.5 alloy with satisfactory mechanical properties and rapid degradation rate was successfully developed,exhibiting a high degradation rate of 6675 mm/a(93℃)in 3 wt.%KCl solution and a favorable ultimate compressive strength of 410 MPa.The degradation rate of Mg97.5Ni1Y1.5 alloy is 2-5 times of the current commercial magnesium alloy fracturing materials. 展开更多
关键词 Mg-Ni-Y magnesium alloys Fracturing ball LPSO phase Degradation rate Mechanical properties
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国外会计盈余价值相关性研究综述及启示 被引量:7
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作者 文远怀 袁淳 《经济研究参考》 2006年第91期40-44,共5页
关键词 会计盈余信息 价值相关性 资本资产定价理论 会计信息 综述 国外 有效市场理论 ball
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Influence of high energy ball milling on Al-30Si powder and ceramic particulate 被引量:12
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作者 LI Yuan yuan(李元元) ZHANG Da tong(张大童) XIAO Zhi yu(肖志宇) 《中国有色金属学会会刊:英文版》 CSCD 2000年第3期324-327,共4页
The influence of high energy ball milling on Al 30Si powder and ceramic particulate SiC was studied by means of SEM, XRD and DSC. The results show that Al 30Si powder and their microstructure are obviously refined aft... The influence of high energy ball milling on Al 30Si powder and ceramic particulate SiC was studied by means of SEM, XRD and DSC. The results show that Al 30Si powder and their microstructure are obviously refined after high energy ball milling process. The alloy powder and SiC p stick closely to each other without interfacial reaction. DSC results detect no reaction but relaxation of the samples. So high energy ball milling can be used as an effective method for ceramic particulate pre treatment in the fabrication of MMC. 展开更多
关键词 HIGH ENERGY ball MILLING interfaces Al 30Si POWDERS CERAMIC POWDERS
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Synthesis of Fe_3O_4 nanoparticles by wet milling iron powder in a planetary ball mill 被引量:11
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作者 Ding Chen Song Ni Zhenhua Chen 《China Particuology》 SCIE EI CAS CSCD 2007年第5期357-358,共2页
Fe3O4 nanoparticles with sizes ranging from 30 to 80 nm were synthesized by wet milling iron powders in a planetary ball mill. The phase composition and the morphologies of the as-synthesized products were measured by... Fe3O4 nanoparticles with sizes ranging from 30 to 80 nm were synthesized by wet milling iron powders in a planetary ball mill. The phase composition and the morphologies of the as-synthesized products were measured by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Nanosized Fe3O4 particles were prepared by wet milling metallic iron powder (-200 mesh, 99%) in a planetary ball mill equipped with stainless steel vials using iron balls under distilled water with a ball-to-powder mass ratio of 50:1 and at a rotation speed of 300 rpm. The use of the iron balls in this method played a key role in Fe3O4 formation. The present technique is simple and the process is easy to carry out. 展开更多
关键词 FE3O4 Wet milling Planetary ball mill
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Progress in the Study of False Smut Disease in Rice 被引量:15
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作者 Xiaoyi Guo Yan Li +3 位作者 Jing Fan Liang Li Fu Huang Wenming Wang 《Journal of Agricultural Science and Technology(A)》 2012年第11期1211-1217,共7页
Rice false smut disease is an increasing concern for research and production, not only because of the increasing epidemic occurrence in rice production, but also the intriguing specific pathogenesis of the disease to ... Rice false smut disease is an increasing concern for research and production, not only because of the increasing epidemic occurrence in rice production, but also the intriguing specific pathogenesis of the disease to be a unique pathological system to enrich the molecular mechanism of plant-microbe interaction. Progresses have been achieved in the pathogen phylogenetic placement, the alternative hosts, the pathogen morphology and diversity, the toxins generated by false smut balls, the artificial inoculation method, and the pathogen transformation as well as rice resistance to the disease. However, it is still controversy on the infection process. It is not clear how the life cycle of this pathogen is coupled with the disease cycle. This review summarized our current understanding on the pathogen, the pathogenesis, and the rice resistance to the disease. Future work should pay attention to developing a more rapid and effective system to evaluate rice resistance and susceptibility to the disease, screening of rice germplasm for disease-resistance breeding, studying the resistance inheritance, and investigating the molecular mechanism of rice-false smut fungus interaction. 展开更多
关键词 RICE false smut disease false smut ball disease cycle resistance review.
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超环面行星蜗杆传动啮合特性研究 被引量:9
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作者 许立忠 王灵忠 赵永生 《农业机械学报》 EI CAS CSCD 北大核心 1997年第4期139-143,共5页
采用空间啮合理论对超环面行星蜗杆传动的啮合特性进行了系统的研究。给出了定子螺旋面和转子蜗杆齿廓曲面方程以及行星轮轮齿滚珠与定子螺旋面及转子蜗杆之间的接触线方程。以上述工作为基础,进而导出了行星轮轮齿滚珠与定子螺旋面及... 采用空间啮合理论对超环面行星蜗杆传动的啮合特性进行了系统的研究。给出了定子螺旋面和转子蜗杆齿廓曲面方程以及行星轮轮齿滚珠与定子螺旋面及转子蜗杆之间的接触线方程。以上述工作为基础,进而导出了行星轮轮齿滚珠与定子螺旋面及转子蜗杆之间的接触线上诱导法曲率以及接触线与相对速度之间夹角计算公式。分析了啮合特性的影响因素和影响规律,为该种传动的设计与制造提供了理论依据。 展开更多
关键词 蜗杆传动 啮合 滚珠
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Fabrication,microstructures,and properties of copper matrix composites reinforced by molybdenum-coated carbon nanotubes 被引量:12
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作者 NIE Junhui JIA Chengchang +3 位作者 JIA Xian ZHANG Yafeng SHI Na LI Yi 《Rare Metals》 SCIE EI CAS CSCD 2011年第4期401-407,共7页
Multiwalled carbon nanotubes (CNTs) were coated by a molybdenum layer using carbonyl thermal decomposition process with a precursor of molybdenum hexacarbonyl. The Mo-coated CNTs (Mo-CNTs) were added into copper p... Multiwalled carbon nanotubes (CNTs) were coated by a molybdenum layer using carbonyl thermal decomposition process with a precursor of molybdenum hexacarbonyl. The Mo-coated CNTs (Mo-CNTs) were added into copper powders to fabricate Mo-CNT/Cu composites by means of mechanical milling followed by spark plasma sintering. The Mo-CNTs were uniform dispersion in the Cu matrix when their contents were 2.5 vo1.%-7.5 vol.%, while some Mo-CNT clusters were clearly observed at additions of 10.0 vo1.%-15.0 vol.% Mo-CNTs in the mixture. The mechanical, electrical, and thermal properties of the Mo-CNT/Cu composites were characterized, and the results showed that the tensile strength and hardness were 2.0 and 2.2 times higher than those of CNT-free specimens, respectively. Moreover, the Mo-CNT/Cu composites exhibited an enhanced thermal conductivity but inferior electrical conductivity compared with sintered pure Cu. The uncoated CNT/Cu composites were fabricated by the similar processes, and the measured tensile strength, hardness, thermal conductivity, and electrical conductivity of the CNT/Cu composites were lower than those of the Mo-CNT/Cu composites. 展开更多
关键词 metallic matrix composites mechanical properties ball milling MOLYBDENUM carbon nanotubes
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Mechanochemical decomposition of pentachlorophenol by ball milling 被引量:11
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作者 WEI Yinglei, YAN Jianhua, LU Shengyong, LI XiaodongState Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第12期1761-1768,共8页
The mechanochemical dechlorination of pentachlorophenol (PCP) was studied using CaO and SiO2 powder as additives. The effects of the milling time and additives on the dechlorination rate were investigated. The resul... The mechanochemical dechlorination of pentachlorophenol (PCP) was studied using CaO and SiO2 powder as additives. The effects of the milling time and additives on the dechlorination rate were investigated. The resulting product was characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), thermogravimetric analysis (TG) and ion chromatography (IC). It is found that grinding operation could dechlorinate PCP, with the formation of inorganic chloride and amorphous carbon. The addition of quartz to the grinding mixture facilitated dechlorination. On the basis of the experimental results, the decomposition mechanism was proposed. Decomposition predominantly proceeds through rupture of C-Cl bond in PCP molecule, followed by the formation of inorganic chlorides. 展开更多
关键词 ball milling DECHLORINATION MECHANOCHEMICAL PENTACHLOROPHENOL
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Dynamic Stability Analysis of Cages in High-Speed Oil-Lubricated Angular Contact Ball Bearings 被引量:13
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作者 刘秀海 邓四二 滕弘飞 《Transactions of Tianjin University》 EI CAS 2011年第1期20-27,共8页
To investigate the cage stability of high-speed oil-lubricated angular contact ball bearings, a dynamic model of cages is developed on the basis of Gupta’s and Meeks’ work. The model can simulate the cage motion und... To investigate the cage stability of high-speed oil-lubricated angular contact ball bearings, a dynamic model of cages is developed on the basis of Gupta’s and Meeks’ work. The model can simulate the cage motion under oil lubrication with all six degrees of freedom. Particularly, the model introduces oil-film damping and hysteresis damping, and deals with the collision contact as imperfect elastic contact. In addition, the effects of inner ring rotational speed, the ratio of pocket clearance to guiding clearance and applied load on the cage stability are investigated by simulating the cage motion with the model. The results can provide a theoretical basis for the design of ball bearing parameters. 展开更多
关键词 dynamic analysis high-speed angular contact ball bearing CAGE STABILITY SIMULATION
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稀土高铬铸铁磨球的稳定化生产 被引量:12
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作者 王仲珏 《铸造设备研究》 2001年第3期18-20,共3页
研究了磨球在磨机筒体中的运动状况和失效原因。针对稀土高铬铸铁磨球的热加工特点 ,为发挥其良好的抗磨性能 ,提出在生产条件下 。
关键词 稀土高铬铸铁 磨球 稳定化生产 铸造
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高硼铸钢的制备与应用 被引量:10
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作者 宋绪丁 蒋志强 符寒光 《铸造技术》 EI CAS 北大核心 2006年第8期805-808,共4页
针对常用磨球材质脆性大、耐磨性低、磨耗高,以硼为主要合金元素,研制了高硼铸钢磨球。为了净化钢液,研究了高硼钢液吹氩净化工艺,选择氩气流量15~25L/min,氩气压力10~15MPa,吹氩时间5~8min,吹氩后钢液的静置时间5~8min的... 针对常用磨球材质脆性大、耐磨性低、磨耗高,以硼为主要合金元素,研制了高硼铸钢磨球。为了净化钢液,研究了高硼钢液吹氩净化工艺,选择氩气流量15~25L/min,氩气压力10~15MPa,吹氩时间5~8min,吹氩后钢液的静置时间5~8min的吹氩净化处理工艺,钢液净化效果好。高硼铸钢磨球经950~1050℃加热后快速淬火和180~250℃回火处理后,具有硬度高、硬度均匀性好和韧性高等特点,用于研磨矿粉和煤粉,磨耗与高铬铸铁球相当,成本降低30%以上,综合效益显著。 展开更多
关键词 高硼铸钢 净化处理 磨球 冲击韧度 耐磨性
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