提高套筒滚子链传动疲劳寿命的优化设计

本文以套筒滚子链传动疲劳寿命为目标函数,对其传统参数的优化设计进行了探讨,通过实例设计,证实了本方法的优越性。     

滚子修形对轴承性能影响的研究

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     

高速陶瓷滚子轴承的疲劳寿命与可靠性分析

陶瓷滚动体密度小，强度高，耐磨损，用于高速轴承可以有效地提高轴承的寿命和可靠度，以最大动态切应力理论和赫兹理论为基础，推导建立了以外圈滚道疲劳失效为准则的高速陶瓷轴承疲劳寿命和可靠度的计算式，并以航空燃气轮机轴承为例，进行了计算和分析。附图１幅，表１个，参考文献５篇。     

凸轮滚子轴承疲劳寿命及滚子接触应力计算

根据凸轮作用在圆柱滚子轴承上的径向力计算了轴承的疲劳寿命;根据凸轮与轴承接触的运动关系计算了滚子轴承的极限转速;分析计算了圆柱滚子轴承的载荷分布,并根据得出的最大滚子载荷计算了轴承的内外圈与滚子的接触应力。结果表明,滚子轴承的极限转速在许用极限转速范围内;轴承外圈的疲劳寿命与滚子的寿命在一般的使用工况下均能达到设计使用要求;滚子与内外圈的最大接触应力在所选用材料的许用应力范围之内。     

圆锥滚子轴承加速试验后的显微组织及疲劳分析

7206E轴承在B30-60R试验机上加速试验后,利用金相SEM、TEM及X射线衍射仪观察测试,其结论是:滚道面未发生严重塑性变形,轴承失效主要是由于润滑油中混入了尘埃、磨屑和外来异物,滚子结构设计不合理造成的几何应力集中,粗大非金属夹杂物和工艺缺陷等原因所致。附图9幅,表2个,参考文献4篇。     

提高滚子冷镦模具寿命的措施

分析影响滚子冷镦模具寿命的因素，提高其使用寿命，节约模具成本。     

A Fatigue Life Comparison of Two-Row Tapered Roller Bearings and Spherical Roller Bearings

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 b_m rating factor to spherical roller bearings compared to a b_m rating factor of 1.10 for that of tapered roller bearings.     

高频焊管机辊轮寿命研究

目前高频焊管机运行不稳定，主要是辊轮寿命较低。本文通过分析和实验，提出了提高辊轮寿命的途径和措施。     

轧辊修复技术探究

介绍了分段镶套法修复冷硬铸铁轧辊的工艺,在实验的基础上分析了高铬铸铁的耐磨特性和耐磨铸套的生产工艺特点,提供了一种轧辊修复再生方案,解决了普通冷硬铸铁轧辊耐磨性差,使用寿命短,设备维修费用高的问题。     

影响托辊寿命的原因分析及改进方案

针对DTⅡ和TD75型托辊使用寿命低的问题,分析了影响托辊寿命的原因,提出了改进托辊结构方案.改进后的托辊寿命提高约5000 h,降低了皮带机的运行成本.     

滚动直线导轨寿命影响因素研究

通过对影响疲劳寿命诸多因素的分析,建议在以后的计算中可采用修正后的寿命计算公式。并针对各因素,提出了延长寿命的措施。     

Optimized Logarithmic Roller Crowning Design of Cylindrical Roller Bearings and Its Experimental Demonstration

A logarithmic profile is essentially an optimal geometry for rolling machine elements such as bearing rollers and raceways. Under most conditions of loading, it yields lower stresses to give longer endurance. Lundberg first suggested the basic profile, and some researchers followed him by modifying it to satisfy engineering requirements. In this article, the authors propose a mathematical optimization method for logarithmic profiles in roller bearing applications. Moreover, rolling contact fatigue life tests are carried out to make a comparison among logarithmically crowned, standard partially crowned, and modified partially crowned rollers. Results show that the logarithmically crowned rollers are beyond the modified partially crowned rollers in fatigue life, especially in poor lubrication conditions, although the logarithmic rollers require less workload to process the crowning.     

Fatigue Life Reduction of Roller Bearings Due to Debris Denting: Part II - Experimental Validation

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.     

滚子链传动振动特性的研究

提出了滚子链传动的横向振动新模型，依据新模型导出了滚子链传动时横向动力响应的表达式     

汽车链滚子元件的高速多冲抗力研究

通过台架和道路行驶试验,利用扫描电镜微观分析了汽车链在正常服役条件下的失效形式。试验结果表明:汽车链传动中滚子元件的失效形式主要表现为冲击疲劳破坏,并伴有疲劳点蚀、磨粒磨损现象。根据试验结果,探讨了合理选择滚子零件的材料及热处理工艺、合理设计滚子的成形工艺和外廓形状等措施,以提高汽车链的抗多冲疲劳断裂和耐磨损的能力。