特殊环境中滚动轴承的润滑

本文综述国外有关在特殊环境中工作的 滚动轴承的润滑问题。对于在液氧和液氢中运转的超低温轴承来说,保持架可用PTFE材料,采用固体润滑剂,并应注意轴承的冷却;超高真空中轴承的润滑材料应选用自润滑性复合材料,并用复合材料做保持架;工作温度高于350℃的高温轴承应采用固体润滑剂进行润滑。文中介绍了有关润滑材料的试验情况。     

基于ADAMS的球轴承保持架动力学仿真

随着滚动轴承性能要求的不断提高,其动力学研究已经成为滚动轴承结构设计、提高轴承性能的不可或缺的组成部分,而保持架的运动性能决定了滚动轴承运动稳定性。因此,在引入一定假设条件的基础上,采用动力学分析软件ADAMS对深沟球轴承进行了动力学仿真,研究了不同工况及不同结构设计参数下保持架的振动特性,为滚动轴承的设计提供支持。     

不同引导方式下保持架运动特性分析

随着对滚动轴承性能的要求越来越高,其动力学特性成为轴承设计至关重要的部分。针对角接触球轴承腔内保持架的运动特性,基于ADAMS建立了保持架不同引导方式下的动力学仿真模型,对比分析了在保持架不同引导方式及不同工况下角接触球轴承腔内保持架打滑率、质心轨迹、质心速度与质心加速度等变化规律。该研究对滚动轴承结构优化设计、提高轴承稳定性具有重要的参考意义。     

聚四氟乙烯基固体润滑保持架材料

本文主要对航天器中常用的聚四氟乙烯基固体润滑保持架材料的填充剂及其对固体润滑保持架材料主要性能的影响进行了研究。     

滚动轴承保持架动力学研究进展

保持架动力学性能对于滚动轴承的高速和噪声性能至关重要,从理论和试验研究两个方面综述了国内、外在滚动轴承保持架动力学方面的主要进展,并对保持架未来的研究方向进行了展望。     

保持架间隙对滚动轴承性能的影响

保持架间隙对滚动轴承性能的影响江苏石油化工学院郑伯伟上海交通大学董师予关键词：滚动轴承,保持架,间隙滚动轴承主要由滚动体、内圈、外圈和保持架组成,其中保持架的作用是将滚动体保持在保持架内,沿圆周均匀分布;同时保持架可以避免滚动体之间相互接触,否则由于...     

固体润滑轴承保持架试验分析

通过固体润滑保持架的磨损转移试验 ,对保持架的摩擦、磨损及转移性能进行了研究。分析可知 ,固体润滑保持架的稳定性取决于钢球与沟道的摩擦性能、保持架兜孔间隙与引导间隙的取值两个方面。另外 ,选择保持架材料时应充分考虑其耐磨性能     

高速高温轴承塑料保持架的研究

1引言 对于滚动轴承保持架，树脂材料因比金属材料具有良好的自润滑性而得到了广泛的应用。通常，能热塑成形的热塑树脂做成的冠形保持架因其生产效率高、易装配而广泛使用。然而，树脂保持架有个问题，那就是在高温下刚度降低，并且由于在高速离心力作用下产生蠕变使得尺寸变化很大。     

高速滚动轴承的动力学分析

在高速轻载的工况条件下，打滑引起的接触表面损坏（如打滑切伤或擦伤）已成为高速滚动轴承的主要失效原因。本文根据牛顿运动定律，建立了滚动轴承动力学模型，分析了轴承元件间的相互作用和滚动轴承的有关动力学特性。利用本文所编制的软件，对滚子的公转和自转转速及保持架转速进行了动态模拟，分析了滚子和保持架的打滑，得到了与实际相符的结果     

N90自润滑保持架材料的研制

滚动轴承常因保持架磨损、疲劳及断裂等原因造成损坏。因此,原子能工业压水反应堆控制机构中使用的轴承,除要求保持架材料具有耐高温、耐水蚀、抗辐射和有一定的物理机械性能外,还要求具有一定的自润滑性和较好的磨合性。为此,我所用粉末冶金方法研制成功N90自润滑保持架材料。经实际使用证明,用这种材料制造的轴承保持架能达到予期的热态寿命,并具有优异的自润滑性能。现将N90自润滑保持架材料的制造工艺及影响材料性能的诸因素分述如下。     

Cage Speed of Hydrodynamic Rolling Hybrid Bearings

Hydrodynamic bearings are subjected to wear during starts and stops due to the absence of sufficient film pressure to effect complete separation of the sliding surfaces. In an earlier publication, our group reported the development of a new hydrodynamic rolling hybrid bearing (HRHB) to overcome the wear problem in hydrodynamic bearings. In the configuration, the transition of operation modes between the rolling bearing supporting state and the hydrodynamic bearing supporting state was realized by the clearance of the rolling bearing. Here we report on the development of a method to identify the operation modes for HRHBs based on monitoring the cage speed of the rolling bearing. The variation of cage speed with the shaft speed is measured. The effects of external load and starting time on the cage speed are also investigated experimentally. The results show that variation in the cage speed reflects changes in the load on the rolling bearing, as well as the operation modes of the HRHBs. With increases in the shaft speed, the variation in the cage speed presents three stages: the increasing stage, the decreasing stage, and the stationary stage. In the first two stages, the HRHB works at the rolling bearing supporting state while in stationary stage, the HRHB works at the hydrodynamic bearing supporting state. In additions to its property of no wear sufferance during starts and stops, compared to hydrodynamic bearings there is little risk of catastrophic failure with HRHBs during any interruption to the lubricant supply and compared to rolling bearings there is no fatigue failure. Therefore this hybrid design is useful at very high speeds.     

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。     

Lubricant Life Tests on Ball Bearings for Space Applications

An experimental program has been conducted to compare the effective lives of ball bearings operating in vacuum with various types of MoS₂ solid films, and with a special high vacuum oil, as lubricants. The test bearings were size 205 bearings running at 30 rpm under a ten-pound radial load. Two particular combinations were also evaluated in oscillating motion tests. Torque was used as the criterion for failure. Prior to test the bearings were subjected to a 2100-pound static load to simulate launch loading. The results of these tests showed that most of the solid film-lubricated bearings were effective for the first several hundred hours, then gave high and erratic torque values as the result of debris being formed by wear of the lubricant film. A sodium-silicate bonded solid lubricant film, which contained MoS₂ and graphite, was found to be particularly promising in both rotation and oscillation. One particularly significant result of this work was the finding that the oil-lubricated bearings showed a sudden, large increase in torque after running effectively for about 1400 hours in vacuum. This behavior has often been predicted but has apparently never been observed experimentally, at least for rolling-contact hearings.     

转速波动工况滚动轴承打滑动力学特性分析

滚动轴承实际运转过程中经常存在的转速波动现象,对滚动轴承的运行状态产生重要影响。基于Hertz接触理论和变形-位移相容条件建立滚动体与套圈的相互作用模型,采用非线性弹簧模拟滚动体与保持架间的相互作用,建立了转速波动工况下滚动轴承打滑动力学模型。通过与实验测试结果的对比,验证了所提出的动力学模型的正确性,并在此基础上分析了转速波动对滚动轴承打滑的影响及不同转速波动幅值、频率下滚动轴承的打滑特性。结果表明:轴承转速波动会造成保持架转速出现波动,导致轴承出现打滑,且滑动主要出现在滚动体与内圈之间;转速波动幅值对轴承打滑影响较大而频率影响较小。     

An experimental investigation into the friction and wear characteristics of unlubricated roller bearings

Lubricated rolling element bearings usually fail by fatigue. In the case of unlubricated rolling element bearings failure is due to wear of the rolling elements and cage. As the amount of wear increases so the friction torque of the bearing increases until catastrophic failure occurs and the bearing seizes.     

滚动轴承的磁流体密封及其性能

利用磁性流体良好的润滑和自密封性能，选择饱和蒸气压极低的基液和分散剂，使磁性流体达到极低的蒸发性能，将其应用到高真空洁净环境中的滚动轴承上。经动力学分析，效果良好，与陶瓷氮化硅轴承及聚四氟烯涂膜的轴承相比，有良好的性价比。     

双曲率兜孔静音轴承保持架设计

传统深沟球轴承浪形保持架兜孔一般采用球形或椭球形结构,轴承在高速运转时滚动体不能充分润滑,存在噪声大、滚动体可能被划伤、使用寿命短等问题。文中在总结对比国内外保持架设计研究方法的基础上,以改善滚动体和保持架的润滑为目标,设计了一种具有双曲率兜孔结构的浪形保持架,分析了所设计保持架的减振降噪机理,最后通过测试验证了该结构能够有效地减振降噪,达到了静音轴承的标准。     

陶瓷滚动轴承在高速主轴单元中的应用

为了提高生产率和加工精度，机床主轴向高速化发展的趋势引人注目，陶瓷滚动轴承具有一系列的优良性能，在高速及特殊环境等条件下工作的机械中，正逐步得到应用。介绍陶瓷滚动轴承的特声、及其在高速主轴单元中的应用，为陶瓷轴承的实际应用提供一定的依据。     

Rolling Bearing Performance and Film Formation Behavior of Four Multiply Alkylated Cyclopentane (MAC) Base Greases for Space Applications

Four multiply alkylated cyclopentane (MAC)-based greases, used for space applications, were used for rolling contact fatigue tests employing thrust ball bearings. These greases were R2000, ML, MU, and 5200 and were made from the same base oil 2001A. Each grease had a different thickener, which were sodium soap, Li soap, urea, and polytetrafluoroethylene (PTFE), respectively. The effect of the grease thickener on the ball bearings' fatigue life in vacuum and atmospheric environments was investigated via testing. For the greases R2000, MU, and ML it was found that the oil film formation in the experiments performed under vacuum conditions declined remarkably in comparison to under atmospheric conditions. For the 5200 grease, the oil film formation was almost the same as under atmospheric conditions. These results were supported by the occurrence of cage wear in the ball bearing fatigue tests. In the absence of sufficient films, high wear rates were measured.     

Materials in Rolling Element Bearings for Normal and Elevated (450°F) Temperature

The effect of vacuum melting has been under investigation by the author's company for several years. Fatigue testing has been conducted on races and balls in full-sized bearings, so that the results can be interpreted directly into bearing performance.

Studies have been made of both induction and consumable electrode vacuum melted steel. Material inspection has shown a more consistently high level of cleanliness in consumable electrode vacuum steel than that melted by induction.

Improvement in life of bearings made of vacuum melted steels does not appear to be commensurate with the improvement in cleanliness. This is regarded as confirming evidence to a long-held view that cleanliness is not the only factor involved in the fatigue property of steel. Fatigue studies have been made of both 52100 and high temperature steels. Bearing ratings range from 17% less than the AFBMA basic load rating to 23% greater than this rating for vacuum melted 52100 steel. In a test of vacuum melted tool steel (M–1), the bearing load rating was 22% greater than the basic load rating for 52100 steel.

There is no indication that vacuum melting has served to reduce the number of early failures more proportionately. Where there has been a change in life, the curve of bearing lives has been displaced, but retains the same general shape.