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This paper reports on the roller skew in tapered roller bearings monitored by contact potential difference probes. The effect of the load, rotational speed, and viscosity of lubricant on roller skew angle, along with the variation of bearing torque with the running conditions, were measured on a LM501300 bearing. Two greases (SHC15 and SHC460) were used to lubricate the bearing. The skew angles were found to vary from 0.15° to 0.6°. The results indicate that the skew angle depends on the friction force at the roller-rib interface. An empirical equation is derived which relates the skew angle to the bearing operational parameters. 相似文献
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Tests were run to compare the fatigue life of two-row tapered roller bearings to that of spherical roller bearings. Both bearing types had an outer diameter of 110 mm with the spherical roller bearing having a 22 percent larger dynamic radial load rating than the tapered roller bearings. All tests were run at 165 percent of the respective two-row dynamic radial load ratings. The results show that both the indirect mounting (double cup or outer ring) and the direct mounting (double cone or inner ring) tapered roller bearings gave significantly better fatigue lives than the spherical roller bearings. These results appear to contradict the present ISO 281 standard which assigns a 1.15 bm rating factor to spherical roller bearings compared to a bm rating factor of 1.10 for that of tapered roller bearings. 相似文献
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An Association of American Railroads (AAR) class F (6 1/2 × 12) tapered-roller bearing assembly is modeled, using finite elements, to examine thermally-induced failures observed in the laboratory when the bearing is operating at relatively high speeds. It is hypothesized that this failure is caused by an unstable thermal expansion/internal bearing load feedback process. Sequentially-coupled, transient thermal and static structural models are used to obtain the thermal-mechanical transient time response as a function of speed, seal type, and lubricant starvation at the rib contact. The model assumes no external loads and zero initial preload (zero end-play). Therefore, the loads developed in the bearing are thermally-induced and self-equilibrated. Two train speeds, viz. 80 and 100 mph, are considered. Simulation results indicate that at axle rotational speeds equivalent to a train speed of 100 mph, a combination of grease starvation and heat flux from the contact seals cause high rib temperature and subsequent unstable load growth which will lead to failure. At rotational speeds equivalent to train speeds of 80 mph or for bearing assemblies that utilize special design seals, the rib temperature is relatively low and no operational instabilities were observed for the model used. 相似文献
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A model is developed to describe the effects of adapter crown wear on the misalignment of a railroad tapered-roller bearing. Wear of the crowned surface results in a flat on top of the adapter. This flat, in contact with the wear plate, is shown to have the capacity to transmit a moment between the bearing and the side-frame of the truck. The magnitude of the moment transmitted is dependent on the length of the flat. These analytical results are coupled with model results from a bearing manufacturer, which give the relationship between bearing misalignment, and thus transmitted moment, and reduction in fatigue life of the bearing. The analysis indicates that a slightly worn adapter has no appreciable effect on the rated fatigue life of the bearing, but once a threshold level in adapter crown wear is reached, the bearing fatigue life will begin to decrease. Large amounts of adapter crown wear will result in significant bearing misalignment and a corresponding reduction in the fatigue life of the bearing. 相似文献
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Life tests have been conducted for tapered roller bearings. Bearing race ways are pre-dented with particles of various types and sizes. Life reductions due to surface indentation are calculated by a stress-based life model using the measured raceway topography. The predictions are compared and validated with testing results. The study concludes that bearing life reduction is primarily determined by the slopes and area densities of surface indentations. Life reduction factor decreases as dent slope and area-density increase. The hardness and fracture toughness of the denting particles have a noticeable effect on bearing life reduction. Ductile particles cause more severe life reduction than the brittle particles. Surface failures associated with small dents are superficial and often appear in forms of “micro-pitting” and “micro-peeling.” Large dents generated by ductile particles cause severe damage to bearing raceways and are more likely to induce surface pits and spalls. 相似文献
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滚子修形对轴承性能影响的研究 总被引:3,自引:2,他引:3
为了提高滚子轴承的工作寿命和承载能力,普遍采用滚子修形。本文研究了直线滚子、全凸滚子、凸弧-直线滚子和对数滚子的母线方程及修形参数,在相同的工况条件下,分析计算了这四种滚子的接触应力沿接触线的变化情况,得出了对数滚子具有最佳受载状态的结论。并以提高轴承工作寿命为目标,建立了确定最佳修形量的数学模型,分析了修形量对轴承受载特性的影响,得出了滚子合理修形可以显著改善高速滚子轴承受载状态的结论 相似文献
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圆锥滚子轴承动态刚度分析 总被引:4,自引:0,他引:4
圆锥滚子轴承承受 5个方向上的载荷 ,相应地产生 5个方向上的位移 ,同时考虑到滚子的惯性力 ,导出了相应的刚度计算模型 ,并给出了计算实例 ,为轴承设计和工况选用提供了分析方法。附图 1幅 ,参考文献 4篇。 相似文献
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高速滚子轴承的拟动态分析计算 总被引:2,自引:0,他引:2
本文建立了高速滚子轴承的拟动态分析计算模型和方法,研究了浪子凸度、滚子倾斜及滚子歪斜等因素对高速滚子轴承工作性能的影响。采用分片计算法确定滚子上载荷分布规律,用数值稳定性好的BFGS变尺度法求解非线性方程组。通过对某航空发动机转子的圆柱滚子轴承进行分析计算,证实了本文方法的实用性。 相似文献
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应用Pro/E与ADAMS软件对圆锥滚子轴承进行联合仿真分析,利用接触碰撞理论模拟轴承实际工作状态,得到滚子与套圈以及滚子与保持架的接触载荷变化情况,获得了圆锥滚子轴承的动态特性,提高了计算效率,并为圆锥滚子轴承的动态设计提供理论依据。 相似文献
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对数修形圆锥滚子的弹流润滑分析 总被引:5,自引:0,他引:5
考虑接触体表面的弹性变形效应与润滑剂的压粘效应,建立圆锥滚子轴承的弹性流体动力润滑模型;并进行了完全数值解分析,得到了流体动压力分布、油膜形状与表面层内Mises应力分布。分析了对数修形圆锥滚子的弹流润滑特性。结果表明,直母线的圆锥滚子的弹流压力分布在滚子两端存在压力峰,并在滚子表层有应力集中现象;而对数母线的滚子在两端区域没有很高的压力峰和应力集中。滚子大端的流体动压力较高,而滚子的小端压力较低;在滚子的两端区域存在较小的油膜厚度,而且滚子小端的油膜厚度更薄;对数修形的圆锥滚子的最小油膜厚度增大,而中心油膜厚度减小;总体上对数修形滚子的弹流润滑状态得到改善。 相似文献
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分析了218248滚子圆锥面上存在的凹坑状缺陷,其产生原因是由于原材料存在严重的脱碳现象。使表面非常软的滚子在软窜或软磨加工中极易遭受碰撞而形成的。 相似文献
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由某公司生产的30307轴承,在考核其寿命时,试验至174 h时轴承损坏.现对其失效的原因进行分析. 1 表面缺陷形貌观察 拆套后发现外圈、保持架均完好无损坏,而滚子靠近小头处的工作表面沿圆周方向有不同程度的剥落(图1),同时内圈滚道靠近小端面油沟处沿圆周方向存在一条磨印(图2). 相似文献