不对中对膜片联轴器耦合转子轴承系统固有特性的影响

考虑转子系统不对中因素的影响后,建立了膜片联轴器耦合转子 轴承系统的动力学模型,分析了在对中和不对中两种状态下转子系统的特征值、模态和系统的稳定性。结果表明,在一定量的不对中作用下,不对中对系统的临界转速影响不大,系统的模态显著改变;当不对中较大时,对系统动力学特性的影响不可忽略,其中系统的稳定性有恶化的趋势。     

提高冲击式破碎机转子轴承寿命的措施

冲击式（包括锤式和反击式）破碎机由于长期在恶劣条件下工作，加剧了转子轴承的磨损。转子轴承不但价格昂贵，而且更换十分困难，往往造成停产损失。如何采取有效措施来提高冲击式破碎机转子轴承的使用寿命，是制造厂家和用户十分关心的问题。下面是笔者从设计制造方面提出的几条措施，供参考。１正确选择转子轴承的型号和寿命由于双列向心球面滚子轴承具有承载能力强、调心性能好等优点，所以多选用这种型号的轴承作为转子轴承。由于转子轴承的受力十分复杂，很难用理论公式进行计算，有的教科书推荐用经验公式P＝３G（G为转子体质量）…     

轴承预负荷及叶轮质量对高速泵转子动力性能的影响

为抑制振动、优化提升高速泵转子动力性能,对高速泵轴承及转子系统建模,分析轴承预负荷及不锈钢、钛合金诱导轮叶轮状态下对转子动力性能的影响,计算结果表明预负荷的增加能够抑制工作转速下的振动幅值,转子的稳定性降低,但对数衰减率在0.1之上,满足稳定性要求;相比不锈钢诱导轮叶轮,钛合金诱导轮叶轮状态下能够大幅提高转子的临界转速。试验及现场应用表明:振动位移的峰峰值能够控制在合理范围内。预负荷可倾瓦轴承及钛合金诱导轮叶轮的应用优化了转子的动力性能,解决了实际工程问题。     

篦冷机破碎机转子轴承的两种冷却方式

１前言篦冷机在水泥生产线上是关键设备，它不仅可使物料快速冷却，还可以从冷却过程中回收余热进行再利用，同时起着筛分物料和输送物料的作用。篦冷机破碎机则是篦冷机的“咽喉”，它的正常运行直接关系到整条生产线的正常运转，而破碎机转子轴承是容易出问题的地方，本文介绍的内容是篦冷机破碎机转子轴承的两种冷却方式。这里提到的篦冷机破碎机是锤式破碎机。破碎机转子轴承座有两个：一端为固定端，转子轴与轴承座位置相对固定；另一端为活动端，转子轴与轴承座位置相对可以移动，用来补偿转子轴在不同温度下的膨胀量，本文中的轴承座…     

N102JHP径向轴承质量问题初探

Ｎ１０２ＪＨＰ转子振值一直处于“黄灯”区，是影响生产正常进行的一大隐患，而轴承的好坏又是影响转子运行的关键所在。本文从理论上对转子径向轴承进行了一定的分析，说明从轴承图纸到备件加工中存在的一系列问题，并提出相应的解决办法。     

气体轴承透平膨胀制冷机的低频振动特性

针对气体轴承结构的某航空用空气透平膨胀机出现的低频振动现象,进行了不同轴承供气压力与升速率下的转子低频振动特性试验研究。通过分析不同参数下转子的气膜涡动和气膜振荡特性,证实了低频振动对转子运动行为及失稳的影响,在合适的供气压力和升速率下低频振动可以得到有效的抑制和消除。揭示了转子低频振动与系统机械效率之间的关系,并提出了一种计算低频振动耗能的方法。     

JS推力瓦轴承故障分析及处理措施

可倾瓦推力轴承具有瓦块调节灵活、能有效补偿转子的不对中等特点被广泛用于大型机泵。实际运行中,若轴承在设计及制造方面存在缺陷或不足,即使采用类似金斯伯雷结构的轴承同样会出现故障导致机组无法稳定运行。通过对推力轴承的结构原理进行分析,查找出轴承副推力瓦损坏的原因,并采取了针对性的改进措施。     

基于ARMD的轴承特性对转子临界转速的影响

通过改变轴承的油楔数、宽径比和间隙比,运用转子动力学软件ARMD,得到国产某型号双级透平发电装置中转子不同轴承特性下的临界转速。结果表明:采用4油楔轴承的转子一阶临界转速最大,且减小其轴承宽径比及间隙比有利于转子一阶临界转速的提高。     

高速多级空气透平膨胀机转子动力学研究

对一种新型多级同轴空气透平膨胀机进行了转子动力学研究,利用ANSYS建立了转子轴承系统临界转速的理论计算模型,使用半联轴器等效了减速器高速轴的影响,并通过大量升速实验验证了计算结果。研究结果显示该空气透平额定转速位于一阶和二阶临界转速之间,其实际一阶临界转速为18 600r/min,理论计算结果和实验结果误差为2.9%;计算了不同轴承刚度下转子轴承系统的固有频率,并通过转子振型图分析了一阶和二阶临界转速下最大振幅处的位置,为转子的设计提供了理论依据。     

空气压缩机轴承温度高原因分析与对策

空气压缩机作为合成氨装置的关键机组，自投用以来轴承温度居高不下，轴承温度缓慢上涨，长期在120℃以上运行，过高的轴承温度影响机组安全稳定运行。根据机组运行历史结合离心式压缩机相关知识理论，从润滑油系统、转子和轴承的结构等方面进行原因分析，最终找出轴承温度高的原因。     

高速纺丝机筒管夹头的研究

本文对环形夹紧和弹性支承的筒管夹头结构进行了介绍和讨论,并对筒管夹头系统进行动态特性分析和临界转速计算,使其工作转速远离临界转速,避开共振区,从而获得筒管夹头在超越临界转速下安全、平稳和可靠地工作的理论依据。并求得系统中的某些主要参数(支承刚度、轴承间距、系统质量、动不平衡)变化时对临界转速的影响。通过实验校核和验证得出了合理的设计方案。     

Effects of cyclic compression and thermal aging on dynamic properties of neoprene rubber bearings

The dynamic properties of rubber bearings frequently used as isolators in structures could be significantly deteriorated because of the change of microstructure in rubber caused by cyclic compression and thermal aging. As a result, a catastrophic failure of bridges and buildings unexpectedly occurs when they are subjected to earthquake attack. Here, the dynamic properties of neoprene rubber bearings before and after different cycles of compressive loading or various periods of thermal aging were first measured and compared to each other. On the basis of the experimental results, the effects of cyclic compression and thermal aging on the stiffness, energy absorption, and equivalent viscous damping coefficient of neoprene rubber bearings are investigated. It is found that the deterioration of dynamic properties of neoprene rubber bearings caused by either cyclic compression or by thermal aging is significant and should be taken into account in designing rubber bearings. © 2007 Wiley Periodicals, Inc. JAppl Polym Sci, 2008     

基于小波神经网络的滚动轴承故障诊断

根据滚动轴承振动信号的频域变化特征 ,采用小波包分析对其建立频域能量特征向量 ,利用径向基函数神经网络完成滚动轴承故障模式的识别。理论和试验证明了该方法的有效性。     

球磨机润滑油站的运行分析

合理配置球磨机润滑油站，是使球磨机安全运行和延长其使用寿命的一个重要条件。对以动静压轴承为主轴承的球磨机，采用高、低压稀油对其进行强制润滑。较详细地介绍以这种润滑方式所配置的润滑油站的组成、工作特点、工作原理以及在运行中应注意的一些问题。     

The importance of axial misalignment on the long term strength of polyethylene pipe butt fusion joints

The importance of axial misalignment at polyethylene pipe butt fusion joints has been assessed by undertaking elevated temperature lifetime tests. Both medium and high density polyethylene pipes were fusion joined to give aligned and controlled misaligned butt joints. These were tested under either a constant or fluctuating internal pressure loading using conditions that induced failure by slow, stable crck growth. It was observed that the lifetime of a butt joined system depends upon both the internal pressure or pressure range applied and the level of misalignment at the butt fusion joint. Increasing either the internal pressure (range) or the misalignment reduced system performance. These two variables of misalignment and internal pressure (range) may be incorporated into a single parameter, the amplified axial stress (or stress range) at the butt joint. This amplified or butt joint axial stress (or stress range) may be derived by considering the additional bending stresses introduced at the butt joint by virtue of misalignment combined with the axial stress loading.     

Increased flow property of polycarbonate by adding hollow glass beads

The steady shear viscosity and dynamic viscoelastic properties of glass beads (GB) filled polycarbonate (PC) melts were studied at varying filler diameters and concentrations. The PC/GB composites containing small amounts of GB bore lower melt viscosity and dynamic modulus than those of pure PC at studied frequencies and shear rates, showing a “ball‐bearings” effect. For highly filled systems, the viscosity and dynamic modulus were decreased further at higher frequencies and shear rates. This ball‐bearings effect was enhanced by changing the GB from larger to smaller one. The oscillatory experiments with modified shear stress showed a stress‐dependent decrease of the viscoelastic properties, and revealed an interfacial slip mechanism, combined with the polymer chains disentanglement at melt/solid interfaces. The scaling relationship between the relative viscosity and the mean interparticle gap confirmed that the interfacial slip and polymer chains disentanglement were induced by the extremely high local shear developed in the narrow gaps between the nearby rotating spheres. POLYM. ENG. SCI., 45:1119–1131, 2005. © 2005 Society of Plastics Engineers     

反置式高温动态选粉机的研制与应用

第三代选粉机在不同技术条件下,根据不同需要发展了多种类型,反置式高温动态选粉机是专为适应高温物料分选而开发的新型选粉机,由于具有独特的笼轮锥体反置结构,避免了主轴轴承受到高温环境的影响,在实际应用中取得了良好的效果。     

谈陶瓷轴承的应用及市场前景

陶瓷轴承作为一种重要的机械基础件,由于具有金属轴承所无法比拟的优异性能,近年来,在国计民生的各个领域中得到了日益广泛的应用。随着加工技术的不断进步,工艺水平的日益提高,陶瓷轴承的成本不断下降,陶瓷轴承广泛应用的时代已经到来。根据开拓陶瓷轴承是高技术发展的需要,本文阐述了陶瓷轴承的主要用途和应用领域和陶瓷轴承的主要类别;以及陶瓷轴承的主要性能特点;同时指出了陶瓷轴承的市场广阔前景。     

Finite element analysis of the temperature uncertainty during spark plasma sintering: Influence of the experimental procedure

Finite element analysis of the dispersion of the dwell temperature during spark plasma sintering (SPS) was performed considering two error sources: misalignment of the axial pyrometer and a shift of the die relatively to the sample. Both error sources induce comparable temperature deviations. In the case of a pyrometer misalignment, these deviations are sensitive to the sample diameter. The errors have no significant effect on the radial temperature gradient within the sample; however, they modify the level of temperature which can be considerably deviated from the set point in the case of cumulative errors.