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In this paper, the effect of the grinding undercut of the raceways on the longitudinal pressure distribution of the profiled rollers, which are the most popular axial profile employed by the bearing manufacturers, was discussed. Based on the profiled roller geometrical equations and numerical calculation of three-dimensional elastic contact problems of finite length, a new numerical method for calculating the crown drop evaluation considering the effect of grinding undercut was used. The analyses of two structure case, that roller length is greater or less than raceway width, were carried out and compared with each other. The Results show that the width of grinding undercut must be considered in determining the crown drop of rollers. 相似文献
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分析了辊压机粉磨技术的特点,归纳总结了辊压机粉磨技术在水泥厂的应用情况,指出以辊压机作为预粉磨、混合粉磨及联合粉磨是目前较常用的工艺,终粉磨节能效果最好,但要注意对水泥质量的影响。 相似文献
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Elastohydrodynamic Lubrication Studies on Effects of Crowning Value in Roller Bearings 总被引：1，自引：0，他引：1
CHENXiao－yang SHENXue－jin 《上海大学学报(英文版)》2001,5(1):76-81
The purpose of this paper is to present a comparison of numerical calculations and experiment results of optical interferometry in finite line contact for the elastohydrodynamic lubrication(EHL)problem of Lundberg‘s profiled cylindrical roller under the conditions of flooded state,moderate load and material parameter.It shows clearly the effects of crowning value on the variations of oil film shape and thickness.The agreement between numerical analysis and experiment results is very good.The results indicate there must be an optimum crowning value that will induce the thickest and most even oil film in EHL state for a given working condition,and this value is larger than the design value in dry contact state for the same working coditiona. 相似文献
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为确保大型旋转动力设备安全可靠运行,须定期对其核心部件转子进行测频及探伤检测,以评估其工作性能。基于多年的经验积累,研发了一套转子测频分析系统。该系统通过比对叶片固有频率分散度的变化,能够发现设备存在的安全隐患,从而避免设备故障或事故的发生。 相似文献
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连铸机扇形段辊子劣化倾向分析 总被引：1，自引：0，他引：1
贾昕 《辽宁科技学院学报》2006,8(4):25-26
辊面的磨损量是连铸机扇形段辊子失效、修复的一个重要参考依据.本文对本钢1600板坯连铸机的几个主要辊子供货商所供产品在使用中的辊面磨损量进行了劣化分析. 相似文献
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雷泽红 《武汉工程职业技术学院学报》2011,(4):3-6
针对冷轧支撑辊的使用工况和使用要求,合理选择冷轧支撑辊辊身堆焊工艺路线和焊材,通过焊前预热、轧辊表面埋弧堆焊、焊后热处理等措施,实现了Ф1525mm的Cr5辊整体修复,并通过实际生产线上的运行考核,能较好地满足生产使用要求,有效降低了轧钢成本。 相似文献
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吴国胜 《武汉工程职业技术学院学报》2004,16(1):18-25
本文记叙对武钢1700mm连轧机组断裂的3支D．H．合金铸钢支承辊的事故调查、取样检验和失效分析，找出了断裂原因，认为支承辊辊身芯部组织未经球化处理，存在大量夹杂物和碳化物偏聚，有害气体含量严重偏高，造成支承辊辊身抗拉强度和延伸率严重不足，冲击韧性随环境温度变化明显，是这3支支承辊发生断裂的主要因素；建议改进D．H．支承辊熔炼工艺和热处理工艺，增强辊身芯部组织的强韧性，才能提高D．H．支承辊在武钢1700mm连轧机组的使用效果。 相似文献
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石春有 《武汉工程职业技术学院学报》2010,22(3):20-22
重轧生产线BD2区域是轧制线上问题的多发区域,如:打卫板、断梁、粘铁皮、轧辊更换频繁等。多起质量事故问题均于BD2轧辊有关.为此,对影响BD2生产的因素进行调查,对P50、P60的BD2轧辊孔型进行分析,查明事故原因,并就此提出整改措施。 相似文献
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A case study of a significant surface settlement induced by tunneling in permeable strata with the shallow tunneling method is presented in this paper. The measurements of surface settlements along the excavation direction were first analyzed to highlight the impacts of groundwater seepage. Due to the groundwater inflow inside a double-arched tunnel, the surface settlement developed to a high level far beyond the measured crown settlement. The settlement-affected zone extended to 4 times the tunnel height ahead of the forefront heading and 1.5 times the tunnel height behind the hindmost heading. Consolidation resulting from high pore pressure change was considered to be the main mechanism for the large surface settlements. In addition, a 3D fluid-mechanical coupled numerical analysis was carried out to confirm the relationship between the significant surface settlement and pore pressure variation. This analysis reveals that lowering the permeability of the small pipe grouting zone, especially of the primary lining, could lessen the drop in pore pressure in the overlying strata, further reducing the total surface settlement. The numerical results also suggest that the transverse range of vertical displacement could be quite wide, and the settlement developed integrally from the tunnel crown towards the ground surface due to groundwater seepage. Moreover, the effect of advance drainage on surface settlement was investigated based on the same numerical model. Drainage with horizontal boreholes could considerably increase the safety of tunnel heading but had limited impact on surface settlement. Finally, the applications of pre-grouting and advance drainage measures were discussed for tunneling cases in permeable strata. 相似文献
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张瑗 《辽宁科技学院学报》1999,(2)
用有限差分法模拟轧辊正火的冷却过程,得出温度场的一较大温度降低值,据此结果用有限单元法求出此时间内的场中各节点的位移;借以得出单元内的平均应力;且仅为热应力。然后进行热应力对轧辊断裂作用的分析讨论。 相似文献
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红树植物无瓣海桑北移种植的生长适应研究 总被引：1，自引：0，他引：1
分析了北移种植在福建省霞浦、连江、泉港、集美、漳浦5个样地无瓣海桑（Sonneratiaapetala）的存活率、株高、根长、冠幅、生物量及生物量分配,结果表明：无瓣海桑人工引种北界在26°47′N～26°16′N之间,且存活率随着纬度的增高而降低;各样地无瓣海桑营养器官的含水量为：叶〉根〉茎,其含水量均值分别为86．4％、71．0％、63．0％,植株有机质在根茎叶器官分配为茎〉根〉叶;根部的长度和重量随着纬度的升高而下降;株高、冠幅随着纬度的升高有所变化,但没有显著性差异． 相似文献
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本文以平面二次包络环面蜗杆传动为实例,应用数值方法研究空间啮合问题。通过模拟蜗杆磨削过程和蜗轮滚切过程,生成以一组平行平面曲线定义的蜗杆曲面及与之共轭的蜗轮齿面,观察设计参数和加工参数对蜗杆磨削区域大小的影响。这一方法为空间啮合传动曲面检测及预测啮合质量提供了数据基础。 相似文献
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吴海勇 《闽西职业大学学报》2014,(1):106-109
选用钎焊金刚石和固定压头单颗金刚石磨粒磨削玻璃．测量了磨削速度与磨削法向力和切向力的耦合关系,以及不同磨削速度下玻璃表面质量的变化情况。研究表明,磨削法向力和切向力随着磨削速度的增加呈单调递减的趋势,磨削玻璃表面质量（划痕长宽）与磨削速度有着密切关系,划痕尺寸与磨削法向力的变化趋势一致。 相似文献
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Jaehoon Yim 《Educational Studies in Mathematics》2010,73(2):105-120
This study investigated how children tackled a task on division by fractions, and how they formulated numerical algorithms
from their strategies. The task assigned to the students was to find the length of a rectangle given its area and width. The
investigation was carried out as follows: First, the strategies invented by eight 10- or 11-year-old students, all identified
as capable and having positive attitudes towards mathematics, were categorised. Second, the formulation of numerical algorithms
from the strategies constructed by nine students with similar abilities and attitudes towards mathematics was investigated.
The participants developed three types of strategies (making the width equal to 1, making the area equal to 1, and changing
both area and width to natural numbers) and showed the possibility of formulating numerical algorithms for division by fractions
referring to their strategies. 相似文献
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廖昌城 《福建工程学院学报》2015,(3):250-253
提高刀辊材料硬度可减少磨损,延长其使用寿命,提高模切速度,但会导致与之配合的砧辊损伤更为严重。为了使刀辊和砧辊系统总磨损量达到最小,试验研究了刀辊和砧辊的硬度匹配问题。利用滚动磨损试验机研究了刀辊与砧辊的硬度匹配,分析了不同硬度刀辊与砧辊匹配时的摩擦磨损与表面损伤行为。结果表明:不同硬度刀辊和砧辊试样匹配对滚动摩擦系数基本无影响;随刀辊硬度增加,刀辊磨损量呈下降趋势,砧辊磨损量表现为线性增加,刀辊和砧辊总磨损量呈先降低后增加的趋势,当刀辊与砧辊硬度比为1.016时,刀辊和砧辊系统总磨损量达到最小。刀辊硬度对刀辊和砧辊试样表面损伤形貌没有影响,刀辊和砧辊试样表面损伤形貌均表现为表面剥落损伤机制。 相似文献
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Da-wei XUE Ming-can CHEN Mei-xue ZHOU Song CHEN Ying MAO Guo-ping ZHANG 《Journal of Zhejiang University. Science. B》2008,9(12)
To understand genetic patterns of the morphological and physiological traits in flag leaf of barley, a double haploid (DH) population derived from the parents Yerong and Franklin was used to determine quantitative trait loci (QTL) controlling length, width, length/width, and chlorophyll content of flag leaves. A total of 9 QTLs showing significantly additive effect were detected in 8 intervals on 5 chromosomes. The variation of individual QTL ranged from 1.9% to 20.2%. For chlorophyll content expressed as SPAD value, 4 QTLs were identified on chromosomes 2H, 3H and 6H; fur leaf length and width, 2 QTLs located on chromosomes 5H and 7H, and 2 QTLs located on chromosome 5H were detected; and for length/width, 1 QTL was detected on chromosome 7H. The identification of these QTLs associated with the properties of flag leaf is useful for barley improvement in breeding programs. 相似文献