Research on the Influence of Raceway Waviness on the Vibration Characteristics of Deep Groove Ball Bearings

The dynamics model of a 2-degree-of-freedom deep groove ball bearing is established by incorporating the raceway surface waviness model comprising multiple sinusoidal functions superposition.The model is solved using the fourth-order Runge-Kutta method to obtain the vibration characteristics including displacement,velocity,acceleration,and frequency of the bearing.Validation of the model is accomplished through comparison with theoretical vibration frequencies.The influence of the amplitude of waviness of the inner and outer ring raceway surfaces of deep groove ball bearings on the vibration displacement,peak-to-peak vibration displacement and root-mean-square vibration acceleration is analyzed,and the results show that as the amplitude of the inner and outer ring raceway surfaces waviness increases,all the vibration characteristic indexes increase,indicating that the vibration amplitude of the bearings as well as the energy of the waviness-induced shock waveforms increase with the increase of the amplitude of the waviness.

Numerical analysis of loaded stress and central displacement of deep groove ball bearing

The aim of this work is to develop a three-dimensional model of deep groove ball bearing to investigate the loaded stresses and central displacements of bearing rings. The equivalent stresses and central displacements of bearing rings are obtained based on the simulated analysis. Moreover, several parameters, such as load magnitude, raceway groove curvature radius(RGCR), thicknesses of outer and inner rings, are varied to investigate their effects on the equivalent stresses and central displacements of bearing rings. Research results provide useful guidelines for determining the design parameters.

Air flow patterns and noise analysis inside high speed angular contact ball bearings

The vortex formed around the rolling ball and the high pressure region formed around the ball-raceway contact zone are the principle factors that barricades the lubricant entering the bearing cavity, and further causes improper lubrication. The investigation of the air phase flow inside the bearing cavity is essential for the optimization of the oil-air two-phase lubrication method. With the revolutionary reference frame describing the bearing motion, a highly precise air phase flow model inside the angular contact ball bearing cavity was build up. Comprehensive factors such as bearing revolution, ball rotation, and cage structure were considered to investigate the influences on the air phase flow and heat transfer efficiency. The aerodynamic noise was also analyzed. The result shows that the ball spinning leads to the pressure rise and uneven pressure distribution. The air phase velocity, pressure and cage heat transfer efficiency increase as the revolving speed increases. The operating noise is largely due to the impact of the high speed external flow on the bearing. When the center of the oil-air outlet fixes near the inner ring, the aerodynamic noise is reduced. The position near the inner ring on the bigger axial side is the ideal position to fix the lubricating device for the angular contact ball bearing.

Dynamic Stability Analysis of Cages in High-Speed Oil-Lubricated Angular Contact Ball Bearings

To investigate the cage stability of high-speed oil-lubricated angular contact ball bearings, a dynamic model of cages is developed on the basis of Gupta’s and Meeks’ work. The model can simulate the cage motion under oil lubrication with all six degrees of freedom. Particularly, the model introduces oil-film damping and hysteresis damping, and deals with the collision contact as imperfect elastic contact. In addition, the effects of inner ring rotational speed, the ratio of pocket clearance to guiding clearance and applied load on the cage stability are investigated by simulating the cage motion with the model. The results can provide a theoretical basis for the design of ball bearing parameters.

Finite Element Analysis of 6300 Deep Groove Ball Bearing

Rolling bearing is widely used in mechanical support, its general components are the inner ring, outer ring, the ball, retainer etc.. Now many companies in developed countries and university in the rolling bearing as the research object, and has made great progress in design theory, the experiment method and production technology etc. We will use the finite element ANSYS to establish the model of deep groove ball bearing. Through the contact analysis, we can get the contact stress between the rings and balls, strain, contact state, penetration, sliding distance and the friction stress distribution. These values are compared to the theoretical values with Hertz theory, and they have better consistency, provide the good theoretical basis for the optimization design of rolling bearings.

Model of Rotation Accuracy of High-Speed Spindles on Ball Bearings

For the purpose to improve a design quality of high-speed spindle units, we have developed mathematical models and software to simulate a rotation accuracy of spindles running on ball bearings. In order to better understand the mechanics of ball bearings, the dynamic interaction of ball bearings and spindle unit, and the influence of the bearing imperfections on the spindle rotation accuracy, we have carried out computer aided analysis and experimental studies. When doing this, we have found that the spindle rotation accuracy can vary drastically with rotational speed. The influence of bearing preload has a secondary importance. Comparison of the results of these studies has demonstrated adequacy of the models developed to the real spindle units.

ZERO TRANSMISSION AND ITS APPLICATION IN HIGH SPEED CNC MACHINE TOOLS

In order to realize high speed machining,the special requirements for the transmission and sturctrue of CNC machine tool have to be satisfied.A high speed spindle unit driven by a built-in motor is developed.An oil-water heat exchange system is used for cooling the spindle motor.The spindle is supported by Si_4N_3 ceramic ball angular contact bearings. An oil-air lubricator is used to lubricate and cool the spindle bearings.Some special structures are taken for balancing the spindle.

Numerical Research of the Influences of the Outer Raceway Curvature Radii on the EHL Properties of Ball Bearing

Based on numerical simulation, the influences of outer raceway curvature radii on some EHL properties of deep groove ball bearing were studied in detail. It was found that the second peak film pressure value decreases with the increase of curvature radius Ry. The minimal film thickness increases at first and then decreases with the increase of curvature radius Ry. The minimum film thickness reaches the maximal value when curvature radius Ry is about 1.7r. Film thickness becomes thinner with the increase of Rx with keeping other parameters constant. The conclusions obtained in this paper are very helpful to practical design of ball bearings.

聚脲润滑脂稠化剂对球轴承疲劳寿命的影响

采用光干涉法、动态击穿电压测试对3种聚脲润滑脂样品润滑膜厚进行了表征,同时测试了3种样品的轴承疲劳寿命和温升特性,对比研究了聚脲润滑脂稠化剂对润滑状态的影响,结果表明:聚脲润滑脂稠化剂在摩擦副表面吸附形成垫层,阻碍了润滑脂乏油润滑引起的润滑膜厚持续减小;聚脲润滑脂稠化剂的类型、含量对表面起源型剥落的轴承疲劳寿命有显著影响,合理的稠化剂配方可显著延长轴承疲劳寿命,这可能与聚脲润滑脂稠化剂的回流特性相关。

深沟球轴承塑料保持架的联合仿真优化

为改善深沟球轴承塑料保持架的注塑变形问题,以锁口端部收缩值为优化评价指标,采用模流分析对保持架浇口数量、加强筋形状以及玻纤含量进行优化选择,通过Minitab软件设计响应曲面试验并结合分类回归树(CART)模型获得注塑工艺参数的最优预测组合。结果表明,优化后锁口端部收缩值由2.461 mm降至1.092 mm,下降55.63%,保持架注塑变形问题得到明显改善。再基于Helius联合仿真对保持架的熔接痕强度进行分析,将模流分析结果映射到ANSYS并通过结构求解器进行运算,证明了优化后的深沟球轴承塑料保持架无失效风险,熔接痕处强度满足要求。

径向游隙对深沟球轴承疲劳寿命影响精细分析

采用Romax Designer工程分析软件,应用ISO/TS 16281寿命计算方法,根据经典的滚动轴承理论,对某风机用电机轴深沟球轴承,在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ISO/TS 16281寿命进行了大量的计算,重点对轴承的疲劳寿命进行了精细分析,分析了径向游隙对轴承ISO/TS 16281寿命的影响。研究结果表明,径向游隙对寿命的影响不仅仅是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;相同工况条件下,存在一个相对最优的径向游隙,由于所研究电机的两个轴承所受载荷不同,因而相对最优的径向游不同。研究结果可为深沟球轴承的优化设计提供参考。

取向型微沟槽高速球铣加工制备方法及其减摩性能研究

探究直接利用高速球铣加工工艺制备取向型表面微沟槽织构的方法,并对该类型表面微织构的减摩性能进行研究.鉴于高速球铣加工工艺走刀路径灵活可变、表面材料残留几何尺寸与分布形态具备可控性的特点,利用Matlab仿真对高速球铣加工表面形貌进行预测,通过高速球铣加工试验验证仿真结果,并基于流体动压润滑理论,结合Fluent流体仿真分析与高速环-块摩擦磨损试验,对该类型表面微织构的减摩性能进行分析.当切削参数选用径向切深明显大于每齿进给量的组合时,高速球铣加工表面残留材料能够形成明显的微沟槽形貌,且微沟槽特征的取向可由球头铣刀的走刀路径进行控制;微沟槽承载能力与其取向密切相关,随着微沟槽取向角由90°减小至20°,负压区与正压区范围呈现扩大趋势,油膜内逆流效应逐渐减弱,动压效应逐渐增强,微沟槽承载能力提高了20.64%,表面摩擦系数由0.02845降低至0.02165;然而,当取向角过小时,负压区与正压区的范围过小,不能形成有效的收敛楔,微沟槽承载能力下降,表面摩擦系数上升.通过高速球铣加工工艺能够实现取向型表面微沟槽织构的可控制备,且该类表面的减摩性能与取向角α密切相关,在本文研究范围内,取向角为20°时表现出最小的摩擦系数与最高的油膜承载力.本文研究结果可为表面织构造型方法提供一种新思路,能够为满足零件表面的减摩需求提供很好的解决方法.

基于综合熵权-信噪比的球轴承外圈沟道ELID磨削加工参数优化

为提高球轴承外圈沟道表面的加工质量,实现对电解在线砂轮修整ELID磨削加工试验中摆动参数、磨削参数的精确控制,设计正交试验并基于试验数据建立表面质量与加工参数之间的二阶响应模型和指数回归模型;通过熵权理论确定表面粗糙度与轮廓度的综合权重,最终获得最优加工参数,并结合信噪比的基本特性分析加工参数对表面质量的影响程度。结果表明:指数回归模型对表面粗糙度预测较为精确,二阶响应模型对轮廓度预测较为精确,误差均在5%以下;表面粗糙度、轮廓度综合权重分别为0.4568,0.5432,最优加工参数为摆动幅度11°、摆动速度6°/s、砂轮转速19500 r/min、工件转速50 r/min;加工参数的影响程度由大到小依次为摆动幅度、摆动速度、工件转速、砂轮转速。

深沟球轴承喷油润滑搅油损失研究

为了揭示喷油润滑时深沟球轴承搅油损失随喷油润滑条件的变化,提高齿轮箱综合传动系统的性能,建立深沟球轴承喷油润滑下的数值计算模型,并用SKF模型进行验证。采用数值模拟和设计正交方案的方法研究喷油润滑时深沟球轴承内部流场运动状态,以及在不同工况参数下深沟球轴承喷油润滑的搅油损失,并通过极差分析和方差分析确定各个因素对轴承搅油损失的影响程度。研究表明:在喷油润滑过程中,外圈表面润滑油体积分数随着润滑油的进入不断提高,并且逐渐趋于均匀稳定,而内圈表面润滑油体积分数则始终很低;喷嘴角度对轴承内部润滑和搅油功率损失影响很大,当喷嘴朝向外圈时,搅油力矩最小,但润滑性能较差,当喷嘴朝向内圈时,润滑性能最好,但搅油力矩稍大;各个因素对轴承搅油损失影响由大到小顺序为节圆直径、转速、喷油压力、喷嘴直径、温度。研究结果对探究深沟球轴承喷油润滑搅油机制和提升车辆传动效率提供了重要的设计和理论参考。

电机轴承振动特性试验

针对电动机支承轴承的振动问题,以某型变压器鼓风机中电动机非传动端支承轴承为研究对象,在分析转子临界转速的基础上,搭建电动机振动测试系统研究转速、升速率、保持架类型、预载荷和配置游隙等因素对轴承振动特性的影响,试验结果表明:电动机在小于临界转速的工况下运行时,轴承振动频率以电动机转频为主;随着电动机转速的升高,x,y,z方向的振动值均随转速提高而增大,转速对x方向振动的影响最大,对z方向振动的影响最小;电动机启动过程对轴承振动有明显影响,应尽量减小达到工作转速所需时间以避免电动机产生过大的振动;轴承游隙对其振动也存在一定影响,非传动端轴承宜采用CN游隙组;相对于钢制冲压保持架,电机轴承采用尼龙保持架时运转稳定性更好;过大或过小的预载荷均不利于轴承稳定运转。

精密轴承用PEEK保持架结构及注塑工艺优化

针对原PEEK保持架兜孔无锁口,采用侧向抽芯机构进行注塑加工时外圆精度低的问题,将保持架兜孔分成内外两部分且设计为球面,注塑模具采用单分型面注塑模结构。并对注塑工艺浇口结构和浇口数量进行优化,基于正交试验得到最优工艺参数为模具温度180℃、熔体温度390℃、保压时间5 s和保压压力55 MPa。实际加工表明:外径面圆度不大于0.15 mm占86%;拉伸强度远高于65 MPa;200℃高温摩擦系数平均值为0.195,磨痕宽度平均值为0.9625 mm,磨损量平均值为0.1394 mm^(3);与相应公差等级套圈、球合套后,轴承旋转精度达到P4,振动值达到Z4。

基于粒子群-遗传混合算法的深沟球轴承优化设计

为了提高深沟球轴承的服役性能,提出一种基于粒子群-遗传混合算法的优化设计方法。其以额定动载荷和额定静载荷为目标函数,以滚动体直径、节圆直径、滚动体数目和内外圈滚道沟曲率半径系数为设计变量,基于粒子群算法,引入罚函数和遗传交叉、变异操作,解决带约束优化问题求解和局部最优问题。并以6206型轴承为算例,对优化后的轴承进行应力分析和敏感度分析。结果表明,所提出算法的收敛性能较好、优化能力较强、运算速度较快,优化后的深沟球轴承接触应力下降了31.7%,从而验证了所提出方法的有效性。

油气润滑下滚动轴承内润滑油输运与分布试验观察

受限于试验设备与试验条件,针对油气润滑的研究多基于数值模拟或球-盘点接触试验,这不符合轴承内部实际接触情况,特别是轴承内润滑介质的分布与输运的试验研究相对缺乏。搭建滚动轴承润滑行为模拟试验台,采用玻璃外环代替轴承外圈,利用光学方法直接观测油气润滑下滚动轴承内润滑油的分布与供给过程,并以SKF6008深沟球轴承为研究对象,分析转速和供气压力对供油效果的影响,结果表明:油气润滑输运的油滴可铺展在轴承外圈内表面,直接供给接触区;高压气体在较高转速下能够输运供给油层至接触区附近。

基于热弹流理论的球轴承胶合失效研究

基于热弹流理论建立了适用于球轴承的胶合分析模型,通过数值计算方法获得了用来表征胶合程度的温度安全系数和膜厚安全系数在计算域中的分布.针对球轴承提出了其考虑乏油润滑影响的胶合失效判定方法,该方法综合考虑温度及膜厚对球轴承胶合失效的影响,不仅可以判断球轴承滚道与滚动体接触副之间是否发生胶合,还可以确定其发生胶合的具体区域及胶合程度.研究了不同入口油膜厚度、径向载荷和内圈转速对球轴承抗胶合承载能力的影响.结果表明:入口油膜厚度降低、径向载荷增大和内圈转速升高会增加球轴承胶合失效风险.

面向轴承润滑增效的内圈表面沟槽引流可视化仿真与试验研究

高速轴承套圈表面添加沟槽是提升轴承润滑效率的有效手段.针对高速旋转套圈表面沟槽对润滑油流动的引导机理和影响规律研究,本文中通过可视化仿真和试验研究,监测对比了润滑油在轴承光滑内圈和带沟槽内圈表面的流动行为,基于内圈滚道内润滑油流量评估沟槽结构对润滑油的导向效果,最后通过轴承乏油状态下的温升试验验证了分析结果的合理性.结果表明,与光滑内圈相比,具有不同凹槽结构的内圈可能会增强/减弱润滑介质流动,合理/不合理的沟槽设计存在提高/降低轴承润滑效率的可能.