新型空心圆柱滚子轴承振动试验

介绍一种滚动轴承振动卧式测量方案,并运用该方案对新型空心圆柱滚子轴承和实心圆柱滚子轴承的振动性能进行了对比分析,结果表明,在一定条件下,新型空心圆柱滚子轴承的振动性能优于实心圆柱滚子轴承.     

涡轮泵流体静压轴承设计及性能特性分析

针对流体静压轴承在液体火箭发动机涡轮泵中的设计和应用,以现有的滚动轴承支承的涡轮泵转子为应用对象,提出流体静压轴承的参数设计思路,采用粒子群优化算法设计得到支承刚度最大化的轴承结构参数组合,并计算分析所设计轴承的性能以及轴承-转子系统的动力学特性。分析表明：优化设计得到流体静压轴承的承载力和支承刚度可以满足要求,但轴承总流量达泵流量的21%,这会显著降低涡轮泵的总体效率;仅将滚动轴承改为流体静压轴承,而不改变其他结构或布局,转子的稳定性不能满足要求;涡轮泵流体静压轴承转子系统设计时应尽量将轴承布置在转子位移较大的位置,以充分发挥其阻尼作用。     

高精度低摩擦陶瓷球滚动轴承

本文介绍了新开发研制的高精度混合陶瓷轴承的材料性能、精度等级和低启动力矩等特性,加工的陶瓷球精度可以达到G3以上,表面粗糙度可以控制在5nm以下,批量生产混合陶瓷轴承精度可以达到P4级以上。实验表明轴承启动力矩小,无润滑状态下启动力矩比相同类型的钢制轴承小一个数量级以上。轴承极限转速高,脂润滑条件下轴承最高极限转速可达6.7万转,轴承使用寿命是同规格钢球轴承的约3～4倍。轴承精度已经达到国外同类产品的精度水平,但成本只有进口陶瓷轴承的～1/2。     

铁路货车等级轴承一般检修工艺的设计

对货车352226X2D1-2RZ第1等级滚动轴承与352226X2-2RZ原型轴承的结构和检修限度进行比较,对第1等级轴承检修工艺中的尺寸检测、轴向自由游隙测定、注脂及等级轴承与车轴轴颈压装工序进行分析,设计了第1等级轴承一般检修的最佳工艺方案,并针对等级轴承在车间现场一般检修时易出现混装问题,提出了有效的工艺控制措施。     

Effect of operating parameters on the threshold voltages and impedance response of non-insulated rolling element bearings under the action of electrical currents

In the present work, the effects of operating parameters on the threshold voltages and impedance response of non-insulated rolling element bearings under the influence of varying levels of electrical currents have been studied. The voltage-current relationships in the bearings have been established.Investigations reveal that first and second threshold voltages appear under the influence of electrical currents in the bearings, depending on the lubricant resistivity, oil film thickness, bearing conditions and the operating parameters. The detected threshold voltages are primarily responsible for momentary flow of current and the further increase in current intensity with a slight change in potential drop across the bearings. The impedance of the bearings becomes negligible as the current intensity across the bearing increases. However, the impedance is more affected by the speed and film thickness than by the load on the bearings.This paper highlights the mechanism of the process of failure of the bearings, using lubricants with different characteristics. The investigations show that the experimentally evaluated threshold voltage coefficients of the bearings, using high resistivity lubricants, increase with speed and are independent of the loads on the bearings. This behaviour of the threshold coefficients of the bearings is used to predict the threshold voltages at different parameters of operation. However, bearings using low resistivity lubricants do not display the threshold voltage phenomenon.The investigation may also be used to determine the safe levels of potential drop across the bearing elements, to avoid damage of the bearings under different operating parameters and also to assess the film thickness by the measured impedance and current intensity response of the bearings.     

陶瓷球轴承内部结构参数优化设计及其性能试验研究

氮化硅陶瓷是一种较好的滚动轴承材料,在此提出了陶瓷球轴承内部结构参数优化设计的基本原则,建立了其优化设计的数学模型,通过对钢球轴承和陶瓷球轴承的性能对比试验,证明了陶瓷球轴承的高速性能要优于钢球轴承,并验证了陶瓷球轴承优化设计原则。     

航空关节轴承挤压翻边固定的仿真和试验研究

对航空关节轴承挤压翻边安装固定进行了仿真和试验研究,通过ANSYS对轴承挤压翻边和轴向推出力进行了仿真,分析了轴承挤压翻边后相关参数的变化及其影响,对仿真分析结果进行了验证,试验结果与仿真分析的结果基本一致.结果表明,轴承与轴承座间隙配合时,轴承挤压翻边安装会降低轴承的空载启动力矩,现有安装工艺能够满足航空轴承安装固定...     

Effect of fluid film wave bearings on attenuation of gear mesh noise and vibration

The attenuation of the gear mesh noise/vibration by fluid film wave bearings relative to rolling element bearings was experimentally investigated. Tests were performed on a gearbox that can accommodate both rolling element bearings and wave bearings. It was found that at specific speeds and torques, the wave bearings could significantly reduce the noise/vibration compared to rolling element bearings. Because the gear noise is accompanied by noise from other sources, a method was developed to extract from the original signal only the mesh harmonic components.The wave bearing dynamic coefficients were also predicted. It was found that adjusting the wave bearing parameters could considerably increase the capacity of the wave bearings to attenuate the gear mesh noise and vibration.     

高速滚动轴承柔性转子试验机

支承高速柔性转子的滚动轴承的寿命、可靠性及失效形式十分复杂,很难得到准确的理论分析结果。因此新研制了高速滚动轴承柔性转子试验机,可以模拟轴承的载荷、转速、润滑等工况条件,测试支承柔性转子系统的轴承性能,为高速轴承性能分析提供准确的试验数据。对支承柔性转子的滚动轴承进行了试验,验证了试验机的可靠性,发现与刚性转子系统相比,柔性转子系统振幅增大且轴心轨迹复杂,这将影响支承轴承的动力学特性。     

六叶柱形浮环轴承流体动力学特性的边界元分析

采用边界元方法对六叶柱形浮环轴承润滑剂的流体动力学特性进行了研究,得到了六叶柱形浮环轴承润滑区的流场分布、轴瓦内表面上的压力分布及浮环外表面的压力分布. 对几种偏心率下六叶柱形浮环轴承的数值计算结果进行了比较分析,得到几种偏心率下六叶柱形浮环轴承压力随偏心率的变化规律.结果表明:与无浮环轴承相比,在各种偏心率下,多叶浮环提高了轴承的稳定性,内摩擦功耗减少,可延长轴承的使用寿命.采用边界元方法分析多油叶复杂结构的浮环轴承流体动力学特性问题是非常方便有效的.     

机器人用四点接触球轴承旋转精度影响因素

针对机器人用四点接触球轴承旋转精度难以预测和控制的问题,提出了同时考虑轴承内圈沟道和外圈沟道圆度误差的轴承旋转精度数值计算方法。根据轴承内部元件运动学和几何学关系建立轴承旋转精度数值计算模型。使用MATLAB编写轴承旋转精度求解程序,得到内圈沟道圆度误差幅值和谐波阶次、外圈沟道圆度误差幅值和谐波阶次、钢球直径偏差及钢球个数对轴承旋转精度的影响规律。进行了轴承旋转精度试验,验证了仿真结果的正确性。轴承旋转精度涉及很多指标,所研究的四点接触球轴承旋转精度衡量指标指轴承外圈径向跳动。结果表明：轴承外圈径向跳动随着内外沟道圆度误差幅值的增大先平稳后快速增大,随着内圈外沟道圆度误差谐波阶次的增大呈现周期性变化,随着钢球直径偏差的增大呈线性减小,随着轴承内部钢球个数的增大呈指数减小。所建模型解决了四点接触球轴承旋转精度难以进行理论求解的问题,能够准确预测轴承的旋转精度,为四点接触球轴承的精度设计提供了理论基础。     

含铅量对Fe-Pb-3Cu系含油轴承性能的影响

在含油轴承试验机上，通过对Fe-Pb-3Cu系列含油轴承运转时的摩擦系数和温升等性能参数的试验测试对比，讨论了含铅量对Fe-Pb-3Cu系列含油轴承性能的影响。试验结果表明，在不同含铅量的四种Fe-Pb-3Cu系含油轴承中，Fe-20Pb-3Cu含油轴承的摩擦性能为最好。这就说明在Fe-Pb-3Cu系含油轴承中，含铅量太大和太小都对含油轴承的性能不利，只有当含铅量达到一个恰当的值时，含油轴承的摩擦性能才能达到最佳。     

改进的变渗透度含油轴承

本文介绍了作者研制的一种沿圆周方向和半径方向均变渗透度含油轴承，与以往的变渗透度含油轴承相比，其内部结构更为合理，其高低渗透度区过渡平缓，应力集中得到缓和，在制造和使用过程中不易破裂。理论分析与实验研究均表明：与普通含油轴承相比，其性能更为优越。     

风电主轴调心滚子轴承中挡边结构对其性能的影响

以三点支承风电机组传动系统主轴用双列调心滚子轴承为研究对象,介绍了固定中挡边、浮动中挡边、无中挡边3种挡边结构轴承,基于风电主轴轴承典型工况,建立轴承动态分析模型,分析中挡边结构对轴承轴向位移、PV值、滚子偏摆、摩擦功耗的影响.分析结果表明,固定中挡边轴承刚性好,轴向位移小,PV值小,滚子姿态稳定,滚道摩擦功耗低,性能...     

Contact mechanics and lubrication analyses of ceramic-on-metal total hip replacements

Ceramic-on-metal (CoM) total hip replacements have shown reduced wear and friction. Lubrication and contact mechanics analyses play an important role in providing an overall understanding for the tribological performance of CoM bearings. In the present study, the steady-state contact mechanics and elastohydrodynamic lubrication (EHL) and transient EHL of CoM bearings were analyzed. The dry and lubricated contact pressures of CoM bearings showed typical characteristics of hard-on-hard hip bearings. The effects of head radius and radial clearance on the lubrication performance were predicted. CoC and CoM bearings are more likely to benefit full fluid film lubrication than MoM bearings.     

双层气浮平台中气浮支承动力学参数设计的研究

针对双层气浮运动平台中气浮支承动力学参数设计问题,分析了气浮支承动力学参数的一般规律,提出了减小双层气浮平台同步误差的设计原则,并通过两种不同双层气浮平台动力学性能设计方案验证了所提出的设计原则。研究结果表明:选择和设计气足时需综合考虑多方面因素,包括气足承载力、刚度和阻尼参数的合理设计,设计时为了避免产生共振应遵循气足固有频率远离工作频率和平台结构频率的设计原则;当气浮平台对同步特性有需求时,双层气浮平台的气足固有频率应该相等,使双层平台具有相同的动力学性能,对干扰和驱动指令具有相同的响应特性,从而保证两者的同步精度。     

电磁轴承动刚度的自动测量

针对电磁轴承动刚度难以测量的问题,构建了一套简单的刚度测量系统用来自动测量电磁轴承的动刚度。该系统采用电磁轴承的数字控制器、功放、电磁铁作为激振器,电磁轴承的电涡流传感器作为拾振器,自行研制的测量分析系统作为测量分析工具。给出电磁轴承动刚度的测量结果。测量结果表明,该系统能较准确测量电磁轴承的动刚度。此测量系统还可以用于其他轴承刚度的测量,也可用于系统辨识。     

平箔式箔片止推气体轴承静特性的理论研究

根据平箔式箔片止推轴承的结构。导出了求解箔片止推气体轴承特性的方程。利用有限元法进行了数值求解。比较了箔片止推轴承与刚性轴承的不同之处，并讨论了影响箔片止推轴承特性的因素。     

Severity Estimation of Cracked Shaft Vibrations within Fluid Film Bearings

The equations of motion, with four degrees of freedom, taking into consideration the flexibility, damping and cross coupling of the fluid film bearings are derived for a cracked Jeffcott rotor supported on fluid film bearings.

Dimensionless equations are developed for dynamic radial load, dynamic pressure developed in the fluid film bearings and coefficient of dissipation considering the journal vibrations in two harmonics; bearing fluid film stiffness and damping coefficients. These are applied to a cracked Jeffcott rotor supported on different types of bearings, i.e., cylindrical journal bearings, offset cylindrical bearings, tilting pad journal bearings and three-lobe bearings. Based on the allowable dynamic pressure developed in the fluid bearings, the severity of cracked shaft and allowable crack depths are estimated in this study. Measurement of dynamic pressure and dissipation for monitoring the crack growth is suggested. However, 2x vibration is the best indicator of cracks in the shafts.     

滚动轴承内部温度状态监测技术

在摩擦学和传热学理论的基础上,建立了滚动轴承温度场数值仿真模型,对轴承内部温度的分布进行了研究,获得了环境温度、工作载荷和润滑脂容积比变化时轴承温度的修正公式。并以轴承的振动和润滑脂温度为监测参数,建立了轴承状态监测系统。运用温度分布规律对测点温度进行了修正,有效地消除了环境温度、工作载荷以及润滑脂容量变化对报警准确性的影响。