Bending stress of rolling element in elastic composite cylindrical roller bearing

A new structure design method of elastic composite cylindrical roller bearing is proposed, in which PTFE is embedded into a hollow cylindrical rolling element, according to the principle of creative combinations and through innovation research on cylindrical roller bearing structure. In order to systematically investigate the inner wall bending stress of the rolling element in elastic composite cylindrical roller bearing, finite element analysis on different elastic composite cylindrical rolling elements was conducted. The results show that, the bending stress of the elastic composite cylindrical rolling increases along with the increase of hollowness with the same filling material. The bending stress of the elastic composite cylindrical rolling element decreases along with the increase of the elasticity modulus of the material under the same physical dimension. Under the same load, on hollow cylindrical rolling element, the maximum bending tensile stress values of the elastic composite cylindrical rolling element after material filling at 0° and 180° are 8.2% and 9.5%, respectively, lower than those of the deep cavity hollow cylindrical rolling element. In addition, the maximum bending-compressive stress value at 90° is decreased by 6.1%.

Stiffness of high-speed cylindrical roller bearing subjected to radial force and bending moment

Presents a practical way of calculation for stiffness of cylindrical roller bearing based on traditional quasistatic analytical methods subject to radial force and bending moment,which take into consideration the effect of such factors as thickness of oil elastohydrodynamic film,pressure,shear force,friction force of cage,centrifugal force and slides,taken into consideration and presents the results of stiffness calculation with a typical example with an aeroengine cylindrical roller bearing were given in the paper.And,discusses the effect of major parameters’influence on stiffness.

Robust Optimization Method of Cylindrical Roller Bearing by Maximizing Dynamic Capacity Using Evolutionary Algorithms

Optimization of cylindrical roller bearings(CRBs)has been performed using a robust design.It ensures that the changes in the objective function,even in the case of variations in design variables during manufacturing,have a minimum possible value and do not exceed the upper limit of a desired range of percentage variation.Also,it checks the feasibility of design outcome in presence of manufacturing tolerances in design variables.For any rolling element bearing,a long life indicates a satisfactory performance.In the present study,the dynamic load carrying capacity C,which relates to fatigue life,has been optimized using the robust design.In roller bearings,boundary dimensions(i.e.,bearing outer diameter,bore diameter and width)are standard.Hence,the performance is mainly affected by the internal dimensions and not the bearing boundary dimensions mentioned formerly.In spite of this,besides internal dimensions and their tolerances,the tolerances in boundary dimensions have also been taken into consideration for the robust optimization.The problem has been solved with the elitist non-dominating sorting genetic algorithm(NSGA-II).Finally,for the visualization and to ensure manufacturability of CRB using obtained values,radial dimensions drawing of one of the optimized CRB has been made.To check the robustness of obtained design after optimization,a sensitivity analysis has also been carried out to find out how much the variation in the objective function will be in case of variation in optimized value of design variables.Optimized bearings have been found to have improved life as compared with standard ones.

A combined experimental and analytical method to determine the EHL friction force distribution between rollers and outer raceway in a cylindrical roller bearing

Friction force is a crucial factor causing power loss and fatigue spalling of rolling element bearings.A combined experimental and analytical method is proposed to quantitatively determine the elastohydrodynamic lubrication(EHL)friction force distribution between rollers and outer raceway in a cylindrical roller bearing(CRB).An experimental system with the instrumented bearing and housing was developed for measuring radial load distribution and friction torque of bearings.A simplified model of friction force expressed by dimensionless speed,load,and material parameters was given.An inequality constrained optimization problem was established and solved by using an experimental data-driven learning algorithm for determining the uncertain parameters in the model.The effect of speed,load,and lubricant property on friction force and friction coefficient was discussed.

凹坑织构位置对81107轴承摩擦磨损性能的影响

通过在机械零件表面进行织构化来改善其摩擦磨损性能的方法已经得到广泛的认可,但其在滚动轴承的应用与研究较少。考虑到滚子与滚道接触区域的内外侧应力较大而中间位置应力相对较小,在81107轴承的轴圈上分别设计并制备了1/4内侧、1/4外侧、1/2内侧、1/2外侧、3/4内侧、3/4外侧、双侧以及全织构等8种不同位置分布的凹坑织构化试样,并利用MMW-1A型万能摩擦磨损试验机、三维非接触式形貌仪和电子天平等设备进行了试验和表征。结果表明:外侧分布织构试样的摩擦磨损性能比内侧的好;1/4外侧分布试样的摩擦磨损性能最好。与光滑轴承相比,磨损量降低了16%,平均摩擦系数降低了47%。这将为滚动轴承的滚道设计和优化提供重要参考。

Mechanical performance analysis of hollow cylindrical roller bearing of cone bit by FEM

Bearings are key components of cone bit,thus its rapid failure is a major cause of leading to lower life of the bit.To improve the bearing performance and prolong working life,contact mechanics of hollow cylindrical roller bearing of cone bit was simulated.Effects of hollow size,drilling pressure,friction coefficient and fitting clearance on mechanics performance of the bearing were studied.The results show that the maximum equivalent stress of the hollow cylindrical roller bearing appears on the claw journal,and the maximum contact stress appears on the contact pair of the hollow roller.Besides,hollow sizes have a greater impact on the equivalent stress and contact stress of the cylindrical roller,while the influence on the stress of the cone and claw journal is relatively small.With the increasing of the drilling pressure and fitting clearance,equivalent stress and contact stress of bearing parts increase.The friction coefficient has little impact on mechanical performance of the bearing.As the 121/4SWPI517 type hollow cylindrical roller bearing of cone bit an example,the optimal hollow size is 55%,the drilling pressure is 140 kN and the fitting clearance is 0e0.02 mm.

内外圈相对倾斜对圆柱滚子轴承寿命的影响

采用Romax Designer工程分析软件对某大兆瓦风电机组齿轮箱进行整体建模,应用经典滚动轴承理论和“切片法”基本思想,对齿轮箱输出轴圆柱滚子轴承在不同内外圈相对倾斜情况下的接触应力、修形效果和轴承寿命进行大量分析计算;重点对轴承ISO/TS 16281寿命进行分析,分析内外圈相对倾斜量对ISO/TS 16281寿命的影响以及对未修形和对数修形最佳修形凸度量时两种情况下寿命的影响;还将ISO 281寿命和ISO/TS 16281寿命进行对比。研究结果表明,无论轴承是否修形,内外圈相对倾斜对轴承ISO/TS 16281寿命影响非常大,倾斜量越大,ISO/TS 16281寿命越短,对应的最佳修形凸度量越大,相应修形效果越好,ISO/TS 16281:2008额定寿命提高得越大;在内外圈相对倾斜量相同的情况下,ISO/TS 16281寿命与ISO281寿命相差非常大。研究结果可为圆柱滚子轴承优化设计提供参考。

考虑滚道缺陷的圆柱滚子轴承保持架振动特性

基于滚动轴承多体动力学理论,以滚子经过滚道缺陷区域时产生的附加位移表征故障,建立轴承滚道缺陷动力学模型。考虑滚子进出缺陷区域时与滚道间接触载荷的变化,建立圆柱滚子轴承动力学微分方程组并求解,研究滚道缺陷时保持架振动响应规律。结果表明:与正常轴承相比,滚道缺陷会导致保持架与滚子间碰撞力增大且接触频率增加,同时保持架打滑率增大;随缺陷宽度增大,内滚道缺陷时保持架振动加速度级逐渐增加,外滚道缺陷时保持架振动加速度级先减小后增加,缺陷宽度大于1 mm后,内滚道缺陷时保持架的振动加速度级明显更大。

Post-testing measurement of freely movable and diffusible hydrogen in context of WEC formation at cylindrical roller thrust bearings from 100Cr6

Sub-surface crack networks in areas of altered microstructure are a common cause for bearing failures.Due to its appearance under light microscopy,the damage pattern is referred to as White Etching Cracks(WEC).The root causes leading to the formation of WEC are still under debate.Nevertheless,it has already been shown that atomic hydrogen can have an accelerating effect on the formation and propagation of WEC.In addition to hydrogen pre-charging,hydrogen can be released and absorbed during rolling/sliding due to the decomposing of the lubricant and water.The current work focuses on the analysis of the hydrogen content of cylindrical roller thrust bearings after testing in a FE8 type test rig using two different lubricants.Within the framework of this work,two different hydrogen analysis methods were used and assessed regarding their applicability.The results show that the so-called Hydrogen Collecting Analysis(HCA)is more suitable to investigate the correlation between lubricant chemistry and hydrogen content in the test bearings than the Local Hydrogen Analysis(LHA).The measurements with the HCA show a continuously increasing freely movable and diffusible hydrogen content under tribological conditions,which leads to the formation of WEC.Comparative tests with an oil without hydrogen showed that the tendency of the system to fail as a result of WEC can be reduced by using a lubricant without hydride compounds.

考虑轨道不平顺激励的轴箱轴承振动特性分析

轴箱轴承在运行工况下的振动特性对于保障行车安全具有重要意义。首先,基于Ansys与Simpack联合仿真平台,分别建立了轨道-车辆系统动力学模型和考虑外圈局部故障的轴承座-轴承有限元模型;其次,对动力学模型施加轨道不平顺激励,输出轴箱径向载荷作为有限元模型的外载荷;然后,将仿真值与理论值进行对比,证明了所建立的轴箱轴承联合仿真模型的有效性;最后,基于此模型分析了轨道不平顺激励时不同宽度故障以及不同故障边缘对轴承振动特性的影响。结果表明:随着故障宽度的增加,轴箱轴承整体振动加速度RMS逐渐变大,故障冲击的幅值以及包络谱的特征能量值先增大后减小;随着故障边缘平缓程度的增加,轴箱轴承整体振动加速度RMS值、故障冲击的幅值以及包络谱的特征能量值逐渐降低;轨道不平顺激励增加了轴承的振动。

径向游隙对圆柱滚子轴承疲劳寿命的影响

应用经典的滚动轴承理论和“切片法”的基本思想,以某大兆瓦风电机组齿轮箱输出轴轴承为例,采用Romax Designer工程分析软件,计算了圆柱滚子轴承不同径向游隙时的轴承内部载荷分布、接触应力、套圈滚道当量动载荷和寿命,分析径向游隙对轴承ISO/TS 16281寿命的影响。研究结果表明:径向游隙不仅通过对轴承内部载荷分布、接触应力和套圈滚道当量动载荷的影响而对寿命产生影响,还通过对寿命修正系数等因素的影响而对寿命产生影响。研究结果可为滚子类轴承的优化设计提供参考。

弹性环式挤压油膜阻尼器一体化圆柱滚子轴承保持架振动特性分析

航空发动机主轴中滚动轴承为了降低系统振动经常与弹性环式挤压油膜阻尼器(elastic ring squeeze film damper, ERSFD)联合使用。基于滚动轴承动力学理论和流体力学控制方程,采用变步长积分算法建立圆柱滚子轴承与ERSFD耦合的动力学分析模型,对外圈带ERSFD的圆柱滚子轴承保持架振动特性和打滑率进行研究。研究结果表明:与未装配ERSFD的圆柱滚子轴承相比,ERSFD可以提高圆柱滚子轴承保持架的稳定性。过大或过小的弹性环凸台数量与宽度都不利于圆柱滚子轴承保持架的稳定性,需要选择合适的凸台数量和宽度。径向载荷与转速对带弹性环的圆柱滚子轴承保持架稳定性影响显著,保持架涡动频率的谐波次数随着径向载荷的增加而减少,其对应的幅值也减小;保持架涡动频率的谐波次数随着转速的增加而增加,其对应幅值也增加。

异形外圈圆柱滚子轴承径向游隙测量装置设计

针对异形外圈圆柱滚子轴承在高精度、定量载荷条件下的径向游隙测量问题,基于静、动态相结合的测量原理完成了异形外圈圆柱滚子轴承径向游隙测量装置设计。介绍了整机结构以及具体操作步骤,并根据异形外圈圆柱滚子轴承特殊的外圈结构以及自重大引起摩擦力较大的问题采取了加载、测量位置可调整机构以及导轨替代滑动摩擦的设计;对形变误差、径向跳动误差和其他误差进行了分析,各部分误差相对较小。

非稳态工况下外圈带有ERSFD的圆柱滚子轴承保持架动态特性

为降低航空发动机主轴传动系统的振动,通常将弹性环、挤压油膜阻尼器与圆柱滚子轴承联合使用。基于滚动轴承动力学理论和流体力学控制方程,建立了外圈带有弹性环式挤压油膜阻尼器(ERSFD)的圆柱滚子轴承动力学分析模型,采用GSTIFF预估-校正变步长积分法对动力学微分方程组进行求解,分析转速、冲击载荷以及弹性环结构参数(凸台宽度、凸台数量)对外圈带有ERSFD的圆柱滚子轴承保持架动态特性的影响,结果表明:外圈带有ERSFD的圆柱滚子轴承保持架稳定性高于普通圆柱滚子轴承;转速和冲击载荷对保持架动态特性影响较大,保持架打滑率随着转速的增大而增大,随着轴承所受冲击载荷的增大而减小;过大或过小的弹性环凸台数量与宽度都不利于圆柱滚子轴承保持架的稳定性,需要选择合适的凸台数量和宽度。

叶脉形仿生织构化推力圆柱滚子轴承摩擦性能分析与试验

为了研究叶脉形仿生织构对推力圆柱滚子轴承摩擦磨损性能的影响,利用ANSYSWorkbench建立推力圆柱滚子轴承的有限元模型,对试验工况下未织构化和织构化推力圆柱滚子轴承的真实物理状态进行了瞬态动力学分析,并试验验证。利用激光表面织构化技术制备了叶脉形仿生织构试样,并使用MMW-1A立式万能摩擦磨损试验机进行了试验。仿真与试验结果表明:与未织构化轴承相比较,叶脉形仿生织构化轴承摩擦系数的上升拐点明显延长,轴圈、保持架和座圈的磨损率分别降低96.92%、96.74%和98.92%,显著提高了轴承的耐磨性能,与仿真结果一致。这为叶脉形仿生织构设计的理论研究奠定了基础。

二级齿轮减速器高速级轴承动态特性分析

为探究减速器轴承在动载荷作用下的动态特性变化规律,以高速级轴承为研究对象,采用广义有限元法建立了计入轴柔性、齿轮与轴承时变刚度的二级齿轮传动系统动力学模型,求解并获得轴承动载荷。基于显示动力学法建立了轴承有限元模型,计算在动载荷作用下轴承外圈的应变时域历程,并通过试验验证仿真结果的正确性。最后分析了轴承在动载荷和恒定载荷下接触特性以及打滑特性的变化规律,结果表明:在动载荷作用下,动应力波动幅值增加且内圈运动轨迹呈不稳定态势;外圈动态接触力呈余弦分布形式且波动周期与动载荷保持一致;保持架和滚子的打滑率增加,滚子运动轨迹椭圆率减小且出现“滞后承载,提前退出”的承载形式。

三瓣波滚道圆柱滚子轴承径向游隙及预载荷计算

考虑三瓣波滚道波形,推导了三瓣波滚道圆柱滚子轴承径向游隙及其内部预载荷的计算方法,并以某三瓣波滚道圆柱滚子轴承为例,计算了轴承径向游隙并分析了预载荷分布情况以及外滚道波形值、基圆径向游隙对轴承预载荷的影响,结果表明:轴承最大预载荷随着外滚道波形值增大而增大,随着基圆径向游隙增大而减小,说明可以通过外滚道波形值和基圆径向游隙控制轴承最大预载荷。

圆柱滚子轴承摩擦力矩试验机

针对现阶段圆柱滚子轴承摩擦力矩试验机测量载荷较小以及大径向载荷条件下测量精度不高的问题,基于平衡法研制了圆柱滚子轴承摩擦力矩试验机,试验机主体为卧式结构,最大载荷可施加至10 k N,可以在不同转速和润滑条件下测量圆柱滚子轴承的摩擦力矩。基于试验分析了径向载荷对圆柱滚子轴承摩擦力矩的影响规律,结果表明圆柱滚子轴承摩擦力矩随径向载荷的增加逐渐增大,摩擦力矩测量值与理论计算值相差较小,验证了圆柱滚子轴承摩擦力矩试验机的实用性。

考虑磨损的全断面硬岩掘进机主轴承寿命计算

主轴承是全断面硬岩掘进机传动系统的重要部件,在恶劣的服役环境下会因磨损疲劳复合作用导致寿命计算困难,分散性大,因此提出一种考虑磨损的TBM主轴承寿命预测模型。首先,为确定主推滚子载荷,建立主轴承载荷分布计算模型并通过有限元模型进行验证;然后,为获得滚子接触特性,建立滚子与滚道接触的局部有限元模型,以最大接触载荷为输入进行求解;最后,基于Archard磨损理论与连续损伤力学理论对主轴承疲劳寿命进行预测。某4.8 m级TBM主驱动轴承的寿命预测结果表明:滚子中心处不发生磨损,磨损深度从滚子中心到两端先增大后减小,导致最大接触应力从最初边缘处的1253 MPa增大至中心处的1584 MPa,滚子有效接触长度从94 mm增大至96 mm,计算得到主轴承寿命为15778 h。

轮轨冲击对提速客车轴箱轴承系统的影响分析

将铁路车轮踏面扁疤运动模型模拟得到的冲击载荷引入双列圆柱滚子轴承轴箱系统力矩平衡模型,数值分析不同扁疤参数在铁路运行工况下导致的轴箱中组配的圆柱滚子轴承内部接触变形、偏转与局部极限接触应力的影响,进而评估轴箱中组配的圆柱滚子轴承系统的接触疲劳损坏与轮轨冲击接触的相关性,建议扁疤长度控制在40 mm以内。