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齿轮传动啮合接触冲击分析 总被引:28,自引:1,他引:27
基于接触动力学相关理论和齿轮传动物理模型,提出齿轮传动啮合接触冲击概念,研究齿轮啮合传动时由啮合点处速度差异导致的轮齿接触冲击现象,建立齿轮啮合接触冲击模型,给出啮合接触冲击求解算法,分析不同冲击转速、冲击位置对冲击合力、冲击时间和冲击应力的影响,并利用解析计算式对比计算各个冲击位置和冲击速度条件下的最大冲击力,验证数值计算结果的有效性.研究表明:冲击转速和冲击位置对冲击合力、冲击时间以及冲击应力均产生较大影响.同时还给出不同冲击条件下齿面上最大接触应力点在整个冲击接触过程的分布,为接触疲劳和疲劳累积的深入研究提供参考,计算结果表明最大接触应力点集中在齿宽中部附近区域,并且受冲击速度的影响很小. 相似文献
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《机械工程材料》1985,(2)
本文对球磨机各种类型衬板,即ZGMn13衬板、ZGMn13Cr2衬板及ZG42CrMn2SiMo衬板的磨损表面形貌特征进行失效分析,并提出球磨机衬板选材方面的原则。实践表明,球磨机衬板在磨损过程中,一般是高应力碾磨损、凿削式破碎磨损及疲劳磨损的综合表现。由于衬板按装位置不同、磨料硬度,粒度不同以及衬板材质、形状结构等因素影响,衬板磨损的形貌也各不同。其失效方式主要是磨损,其次是断裂。在磨损过程中,磨料夹在衬板与磨球之间,经过磨球与磨料、磨球与衬板、磨球与磨球的撞击和接触,使磨粒受力而刺入衬板表面并产生相对滑移,使衬板表面产生犁皱。同时在压应力作用下,使衬板表面塑性组织产生变形、脆性组织 相似文献
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方斌 《机械工人(热加工)》2005,(7):76-77
我公司热电厂使用的磨球是球磨机主要易损件之一,以往先后使用过抗磨锻钢磨球和球墨铸铁磨球。抗磨锻钢磨球具有韧性好,不易破碎的特点,但是硬度偏低,不耐磨,球耗较高,易失圆;球墨铸铁磨球球化率波动较大,要求严格的热处理工艺,同时球的破碎率较高。目前市场上常见的还有高铬铸铁磨球和低铬铸铁磨球,相对高铬铸铁磨球而言, 相似文献
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火电厂球磨机用金属磨球和衬板,一方面受煤的高应力犁削磨损;另一方面受小能量多次冲击。因而,要求具有一定的耐磨性、韧性和强度。目前国内火电厂球磨机磨球等广泛采用45号钢和高锰钢制造。其使用周期短,更换频繁。据测,火电厂中仅制粉系统,每年钢球磨耗达10万吨以上。为此,我们立足于国内,在实验室试制成高铬锰钛铸铁。采用以锰代钼来提高铸铁的淬透性获得马氏体,加入钛铁以提高硬度和强度,并 相似文献
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球磨机中磨球的失效主要包括两方面,即磨损及碎裂或剥落。由于上述损坏而降低球磨机的效率、增加电耗。一般磨机尺寸愈大,所受冲击作用也愈大,磨球的磨损和碎裂也加剧。因此现代水泥工业中对球的材质提出很迫切的要求,即什么材质为佳?目前国内使用的有锻钢及铸铁二种磨球,其中以高铬铸铁磨球的耐磨性为佳,广泛性于中、小型球磨机上。在φ3.2米以上的磨机上使用,应注意化学成份的调整:碳含量约在2.15~2.75, 相似文献
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空投车辆着陆过程的冲击应力分布状态影响空投车辆油箱的服役可靠性。针对空投车辆跌落过程油箱结构的冲击应力规律研究,建立了充油75%的油箱有限元模型,采用CEL方法对油箱进行流固耦合计算,结合实车空投试验,分析了油箱本体动态应力分布以及液体状态。结果表明:跌落冲击过程,油箱壳体与内部隔板翻边搭接位置处应力最大;油箱底部橡胶缓冲垫是降低油箱结构动态应力的有效形式,缓冲垫接触面积达到原来的四倍,油箱结构动态应力下降10 MPa。研究结果对空投车辆油箱服役可靠性提升有重要的理论指导,也可为空降车空投结构设计与校核提供理论依据。 相似文献
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根据2个钢球Hertz接触的应力分析,推导出球笼式万向节钢球与星形套和钟形壳接触的应力计算式,并对球组节圆直径进行了优化设计,得出钢球与星形套和钟形壳间的最大接触应力与载荷的立方根成正比,优化设计的球组节圆直径系数K=0.54~0.55。 相似文献
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氮化硅陶瓷球滚动接触疲劳寿命模型 总被引:4,自引:0,他引:4
针对球与圆柱接触模型中的陶瓷球,利用WEIBULL断裂统计方法导出球疲劳失效概率与寿命之间的关系方程,在相关额定寿命与最大接触应力的数值解基础上,基于最大主拉应力,构建氮化硅陶瓷球的滚动接触疲劳寿命与接触应力的数学模型.经与不同接触应力水平下的滚动接触疲劳寿命试验结果验证,表明该拉应力一寿命模型的正确性,从而验证了氮化硅陶瓷球的滚动接触疲劳失效源于最大主拉应力,而非基于最大切应力的设想.通过与L.P切应力一寿命模型预测结果的比较,表明拉应力一寿命模型适合于陶瓷球的接触疲劳寿命预测. 相似文献
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Hybrid ceramic ball bearings, which are composed of silicon nitride (Si3N4) balls, ANSI 440C stainless steel rings and PTFE based composite retainers, are tested at high speed and heavy loading in cryogenic conditions. The rolling contact fatigue behavior of steel rings and ceramic balls in liquid nitrogen is analyzed. In addition, four-ball fatigue testing was done at room temperature with oil lubrication. The crush load of ball against ball in liquid nitrogen, which directly relates to the inner quality of the balls, is also evaluated. The results show that the spalling of silicon nitride balls, rather than micro pitting on the steel raceways, is the main cause for the failure of the hybrid ball bearings in liquid nitrogen. The fatigue mechanism of the ceramic balls is similar to that of ceramic balls at room temperature, but the characteristics of crack propagation are different because of differences between the cryogenic liquid medium and oil. Although most of the fatigue cracks originated from internal defects within the ceramic balls, the silicon nitride balls exhibit a high load capacity. When silicon nitride balls are loaded against steel balls, the steel balls are crushed while the silicon nitride balls do not exhibit plastic deformation. When ceramic balls with a 11.113 mm diameter are loaded against each other, crushing takes place at a nominal contact stress of 27~29 GPa. 相似文献
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Tingqiang Yao Liguo Xian Lihua Wang Xiaobao Liu 《Journal of Mechanical Science and Technology》2017,31(9):4119-4135
The dynamics of ball bearings are important to fatigue breakage, dynamic performance and motion precision of mechanisms connected by ball bearings joints with multi-clearances. In this study, a new method is proposed for multibody dynamics analysis on mechanisms under the effects of radial internal clearances and impact of balls/cage pockets interactions of ball bearings. Including balls/rings interactions and balls/cage pockets interactions, the three dimensional dynamics models of the crank slider mechanism are established and calculated by generalized-α algorithms on the basis of Hertzian contact theory and penalty function method. The rules of eccentric trajectories of inner and outer ring center for one ball bearing joint are verified with the results calculated by XU’s references. The results of dynamic errors, motion trajectories, dynamic forces are achieved under different speeds, radial clearances and number of ball bearings. The speeds and radial clearances are critical to the dynamic performances and motion precision of mechanisms, especially the number of ball bearings. The number of ball bearings is important to impact force and motion stability of the mechanism. 相似文献
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ANALYSIS OF MECHANICS IN BALL SPINNING OF THIN-WALLED TUBE 总被引:2,自引:1,他引:1
JIANG Shuyong REN Zhengyi 《机械工程学报(英文版)》2008,21(1):25-30
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. 相似文献
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基于滚动接触蠕滑理论将球轴承滚动体与滚道的接触问题分解为法向赫兹接触子问题和切向粘滑子问题,提出了基于滚动接触蠕滑理论的球轴承摩擦力矩计算方法,揭示了球轴承滚动体相对内外滚道的滚滑粘着运动特性,解决了球轴承滚动体运动姿态难以确定的问题,为固体润滑/干接触条件下球轴承摩擦力矩的准确计算提供了理论依据。在轴向载荷作用下对采用PTFE保持架全陶瓷Si3N4/GCr15/不锈钢球轴承进行摩擦力矩试验,试验结果与计算结果对比表明,球轴承蠕滑分析模型能够得到比较准确的摩擦力矩计算结果,比不考虑滚动接触区粘滑效应的切片离散化模型更准确。 相似文献