高速球轴承的研究和发展

本文在总结高速球轴承运动学、动力学研究的基础上,指出Ｃ．Ｒ．Ｍｅｅｋｓ的保持架六自由度动力学分析模型是一种经济有效的球轴承分析模型。     

滚动轴承弹性接触动态特性有限元分析

滚动轴承弹性滚动接触动态特性直接影响转子系统的精度及动态特性,针对滚动轴承弹性滚动接触动态特性问题,以深沟球轴承61914为例,在同时考虑内环、外环、滚珠及保持架变形的情况下,建立滚动轴承三维弹性滚动接触有限元模型,采用有限单元法计算滚动轴承在不同转速、径向力及轴向力等载荷工况下滚动轴承的接触应力及滚珠与内环的运动状态。结果表明,有限单元法能在满足高精度计算的情况下求解各种复杂工况下的滚动轴承动力学特性,为进一步研究滚动轴承弹性滚动接触动态特性提供有力的研究方法。     

高速角接触球轴承中的冲击滑动研究

高速角接触球轴承中,球与保持架的碰撞会导致球与滚道的冲击滑动,从而引起滚道划伤和轴承早期失效。为探究球与保持架的冲击碰撞导致的瞬时滑动,以某高速角接触球轴承为研究对象,通过对联合载荷下角接触球轴承的动力学仿真,分析了变速工况及保持架结构参数对球与保持架的冲击碰撞、球与滚道的冲击滑动以及零件磨损率的影响。结果发现,加减速及恒定转速下,球与保持架的运动呈现周期性变化;由于球进入和离开径向载荷区域时公转角速度的变化,球与保持架碰撞并导致球相对内、外圈滚道发生冲击滑动;为适应球公转角速度的变化,适当增大兜孔间隙,可以减小球与保持架兜孔碰撞力的大小和频率,从而减小球与滚道的冲击滑动以及保持架的磨损率。     

一种分体式直线分离轴承设计

介绍一种分体式直线轴承,应用于需要相对转动同时也需要作往复直线运动的两个零件之间。分体式直线轴承由外圈、保持架和滚珠、轴组成,保持架的托架根据运动形式选择在轴上或在轴承外圈。当保持架和滚珠在外力作用下移动到某一端时,分体式轴承仍然保证保持架有运动空间,轴和外圈之间相对运动的摩擦力比较小。     

Auto-Eliminating Clearance Auxiliary Bearing Device for Active Magnetic Bearing Systems

An auto-eliminating clearance auxiliary bearing device (ACABD) for active magnetic bearings (AMBs) has recently been designed and a prototype system was tested in this study. ACABD mainly consists of a series of connected tilting supports. In this design, a ball bearing is directly mounted on a rotor as the auxiliary bearing in an AMB system. The outer race of this ball bearing is surrounded by these supports. In the open position, there exists an initial protective clearance between the outer race of the ball bearing and the tilting supports. When the bearing-mounted rotor drops on these supports due to an AMB failure, the friction between the outer race of the ball bearing and the tilting support rotates these supports to eliminate the clearance and recenter the rotor. Due to elimination of the clearance, the possibility of backward whirl of the rotor is eliminated. The movement mechanism of this device is analyzed kinematically. The rotation of these supports, elimination of the protective clearance, as well as the rotor rotating stability after the clearance elimination are discussed from the perspective of statics. Furthermore, a preliminary prototype experimental rig was developed to demonstrate the feasibility of the ACABD after AMB system failure. Experimental results show that, after the AMB system failed, the ACABD immediately eliminated the clearance between the outer race of the ball bearing and the supports and pushed the rotor center close to the initial position.     

Some Dynamic Effects in High-Speed Solid-Lubricated Ball Bearings

Dynamic performance simulations of a high-load, high-speed ball bearing for turbine-engine applications are considered using the available Dynamics of Rolling Element Bearings (DREB) computer program. It is shown that the key element in the bearing design is the traction behavior at the ball/race interface for the prescribed materials. With a given traction model, the geometry of the bearing may be designed to ensure acceptable ball/cage collision forces and to ensure the general stability of the cage.     

A theoretical model to predict the effect of localized defect on vibrations associated with ball bearing

The paper presents an analytical model for predicting the effect of a localized defect on the ball bearing vibrations. In the analytical formulation, the contacts between the ball and the races are considered as non-linear springs. The contact force is calculated using the Hertzian contact deformation theory. A computer program is developed to simulate the defect on the raceways with the results presented in the time domain and frequency domain. The model yields both the frequency and the acceleration of vibration components of the bearing. The effect of the defect size and its location has been investigated. Numerical results for 6305 deep groove ball bearing have been obtained and discussed. The results obtained from the experiments have also been presented.     

具有局部表面损伤的滚动球轴承动力学建模

提出了一种滚动球轴承局部表面损伤故障的动力学分析方法。模型中每个轴承元件具有6个运动自由度,并完整地考虑了陀螺效应、离心力及润滑牵引等动力学因素。通过几何特征的变化对局部表面损伤进行了建模。采用四阶变步长Runge-Kutta-Fehlberg积分法对动力学方程进行了数值求解,并在时域和频域中对动力学响应进行了分析。研究结果表明,由于考虑了润滑剂的牵引效果,计算得到的故障特征频率较纯滚动假设下的计算结果有一定的差异。文中综合考虑了轴承元件的三维运动、相对滑动、润滑效应以及局部表面损伤等因素,因此所提出的模型更为全面、有效和实用。     

A dynamic model of ball bearing for simulating localized defects on outer race using cubic hermite spline

In this paper a dynamic model is presented for predicting the vibration behavior of a ball bearing under the influence of localized defects on the outer race. The calculation of contact force is based on Hertzian contact deformation theory. The pulse generated by the ball striking the defect on outer race is modeled by using the blending functions of the cubic hermite spline. The effect of change in the angular position of the defect, size of the defect on outer race, multiple defects on outer race and the variation of load on the vibration amplitude is predicted by this model. A computer program in MATLAB is developed and the governing equation of motion is solved by Euler’s method. The numerical results are presented as a function of variation of the geometry of the outer race due to the impact at the defect and normal race contact w.r.t. time and the conclusion about the health of the bearing is determined by the spectral analysis. To validate the results, experimentation has also been performed.     

球笼式万向节钢球运动分析与仿真

钢球是球笼式万向节的核心部件之一,它的运动规律对万向节的功能有至关重要的影响。证明钢球球心的内外轨道一定是相交的,在此基础上给出钢球在内外轨道约束下的运动学微分方程,利用所得结果严格证明球笼式万向节的等速性。通过求解钢球运动,对钢球相对于星形套、钟形壳以及球笼的运动进行运动学仿真。仿真结果揭示钢球运动的共性特征:全部钢球都分布在一个以内外轨道中心连线中点为圆心的圆上,钢球在分布圆上的方位角变化率在输入角速度数值附近周期性变化,且各不相等;钢球相对内外轨道的弧线位移大小相等、方向相反;钢球相对球笼槽中心存在沿径向和切向位移,相对位移均随时间周期性变化。研究结果为球笼式万向节的设计提供了参考。     

推力球轴承接触问题有限元分析

推力球轴承是被广泛应用的支承机械,用于承受转速较低的轴向载荷.它是由上下座圈、保持架和球体组成的可分离结构,分为单向推力球轴承和双向推力球轴承两种.着重分析了不同尺寸、形状的球形滚动体和橄榄球形滚动体对接触情况下的应力和变形量的影响.使用Pro/E建立实体模型,导入ANSYS进行数值模拟和计算.通过对获得的数值模拟结果和赫兹理论解进行对比,结果表明有限元分析是比较准确而且可靠的.最大接触应力和弹性趋近量取决于滚动体与滚道接触处的主曲率和、主曲率差,与滚动体形状、体积没有直接联系.     

Measurement of Cage and Pocket Friction in a Ball Bearing for Use in a Simulation Program

Few measurements have ever been made of the drag forces arising in a ball bearing due to viscous friction of the balls rotating in the cage pockets and the cage rotating inside the raceway. This paper reports measurements of both these sources of friction on simulations of just one bearing, but the data are compared with general analytical expressions for predicting the friction, and agreement is good. Finally, the data for the ball/pocket friction are compared against a theoretical model based on simple viscous shear and are shown to be in excellent agreement.     

铁路大型养路机械信号干扰与抑制方法研究

为抑制对讲机高频载波信号对铁路大型养路机械传感器信号的干扰,通过使用高频示波器采集干扰信号并对电感式开/关量传感器的工作原理进行分析,同时运用仿真软件对高频干扰信号与传感器内部的LC振荡电路进行仿真;通过仿真分析发现高频干扰信号与传感器电源信号相叠加影响了LC振荡电路的正常起振;并在π型电源滤波电路的基础上通过仿真计算结合现场试验的方法找到合适的滤波电感值,最终消除了高频干扰对传感器的影响使传感器工作正常。     

角接触球轴承流固耦合仿真分析

角接触球轴承在运行过程中的润滑状况至关重要,润滑油直接影响滚动轴承的接触状态。为分析角接触球轴承的润滑状况以及考虑润滑时轴承的机械特性,基于有限元和晶格玻尔兹曼方法,建立了双向流固耦合轴承仿真模型,对角接触球轴承进行动力学有限元仿真和润滑流体仿真,并与轴承拟静力学理论计算结果进行对比,验证模型的准确性。分析结果表明,保持架与滚珠接触并撞击,在轴承腔内油膜压力最大,滚珠与内圈、外圈滚道接触区分别为第二、第三大油膜压力区。润滑油受滚珠公转影响,沿着滚珠转动方向流动,实现对滚珠与内圈、外圈和保持架之间的润滑。滚珠运动和最大接触应力仿真结果与轴承拟静力学理论求解结果一致,即流固耦合仿真模型计算轴承机械特性具有较高的准确性。     

滚动轴承故障特征的时间—小波能量谱提取方法

振动信号中的周期性冲击现象是诊断滚动轴承各元件故障的重要依据之一,针对滚动轴承故障特征,在小波变换理论基础上提出一种时间—小波能量谱信号处理方法,它能够有效地提取出振动信号中冲击成分的时域和频域特征。利用时间—小波能量谱方法分析正常、外圈故障、内圈故障、滚珠故障等四种状态下滚动轴承的振动信号,并与传统的包络解调分析方法进行对比分析。时间—小波能量谱不仅可以有效提取出冲击特征明显的滚动轴承外圈故障,还能提取出内圈、滚珠等信号特征微弱的滚动轴承故障,而包络解调分析方法只能提取出外圈故障特征而不能提取出滚珠故障、内圈故障特征。结果表明,时间—小波能量普比包络解调分析方法更能有效地提取出振动信号中的冲击信号成分。     

内、外双锁口圆孔实体保持架加工方法的改进

针对三、四点角接触球轴承内、外双锁口圆孔实体保持架加工难度大、生产效率低,并且保持架材料调质后硬度高、加工困难的问题,通过改变常规的加工工艺流程及刀具,制定了可行的内、外双锁口圆孔实体保持架的加工方法。     

Application of an envelope technique in the detection of ball bearing defects in a laboratory experiment

To judge the diagnostic capabilities of an envelope technique, based on enveloping the resonance frequency of a transducer,

1 Bearcon Signature™, Carl Schenck AG, Germany

artificially damaged ball bearings (SKF 6207) were run under oil lubrication at different radial loads and speeds in a laboratory experiment. Damage to the outer race, inner race and ball of different magnitudes was introduced by spark erosion and the response of the measurement system was analysed. The results showed that vibration spectrum components of outer race defects showed up in the envelope spectra of undamaged bearings, and that the detectability of defects was primarily limited by the speed of the bearing; on occasion the automatic scaling facility of the analyser was a limiting factor. Inner race and ball defects showed the well-known effects of load modulation in the defect contact zone, which can become dominant in the envelope spectra at high loads and speeds. This phenomenon could be confirmed by computer simulation. The detection of ball damage was hampered by the fact that overrolling of the defect in purely radially loaded bearings takes place incidentally. This drawback could be mitigated by applying a trigger technique to the envelope signal.     

Predicting polygonal-shaped defects during hot ring rolling using a rigid-viscoplastic finite element method

We applied a rigid-viscoplastic finite element method to investigate polygonal-shaped defects that occur during ring rolling and developed an improved analysis model with relatively fine finite elements near the roll gap to reduce the computational time, along with a scheme to minimize the volume change. We also simulated the formation of a polygonal-shaped defect during hot ring rolling of a ball bearing outer race. The results were in good qualitative agreement with actual experimental phenomena.     

钢丝滚道球轴承的点接触问题有限元仿真

以某型飞行器三轴仿真转台主轴轴系中的钢丝滚道球轴承为例,通过ANSYS对该滚珠．滚道间的非协调性接触问题进行有限元建模与仿真,发现最大接触应力发生在钢丝滚道的表面,而滚珠的最大接触应力发生在其接触面正下方短距离内。有限元分析结果有力地阐明了点蚀易在钢丝滚道接触表面形成并逐渐扩展的机理。本文的工作为进一步开展钢丝滚道的点蚀及磨损的实验研究提供了理论依据。