平面螺旋槽动压止推气体轴承的设计

本文简要回顾了平面螺旋槽动压止推气体轴承理论设计的发展，对平面螺旋槽动压止推气体轴承的稳态特性进行了有限元数值求解，与经典设计选用数据对比进行了综合分析，提出了该形式轴承的设计准则。     

提高小孔供气静压气体径向轴承稳定性方法的探讨

对通过向轴承系统引入附加阻尼以提高小孔供气静压气体径向轴承稳定性的方法进行了回顾和分析，介绍了“O”形橡胶圈加稳、Sixsmith式、双气膜、切向进气四种附加阻尼的小孔供气静压气体径向轴承和胶圈加稳切向小孔供气及双气膜切向小孔供气两种复合形式的小孔供气静压气体径向轴承。并对这几种轴承的结构型式、研究发展、应用范围和优缺点进行了详细的描述。     

小孔节流静压止推气体轴承静特性的数值分析

介绍了计算流体力学软件 FLUENT 及其在气体轴承研究中的应用.针对环形小孔节流静压止推气体轴承,基于 FLUENT 软件进行了简化假设并建立了计算模型,利用 FLUENT 软件对止推气体轴承模型进行了数值分析,求解了环形小孔节流静压止推气体轴承的压力场分布、耗气量和承载能力等轴承静特性,并成功捕捉到了大气膜间隙下供气孔周围的压力突降区.对计算结果进行了分析,并与文献计算值以及试验值进行了对比,验证了数值分析的可靠性.     

气体静压小孔节流与多孔质节流性能的比较

本文给出了传统的小孔节流和多孔质节流轴承的理论分析，分析了外部供压气体轴承的进气形式对轴承性能的影响，对于不同类型的小孔节流和多孔质节流的轴承，本文给出了实验结果，并对轴承的性能参数即承载能力，刚度等进行了比较，作者分析了小孔节流和多孔节流止推轴承的承载能力和刚度，结果表明多孔质止推轴承同小孔节流轴承相比，具有高的承载能力。     

高速动压气体轴承箔片材料表面处理的探讨

针对高速透平机械动压气体轴承——箔片式气体轴承金属箔片材料的表面处理问题进行了一定的探讨。对箔片式气体轴承箔片材料的选择、材料的表面处理方法以及该轴承的启停性能和稳定性进行了实验研究。分析表明：通过对箔片材料及表面处理方法的合理选择，可以显著改善箔片式动压气体轴承的启停性能。     

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。     

几何形误差对气体静压圆柱轴承运动精度的影响

几何形误差是影响气体静压圆柱轴承运动精度的主要因素之一。本文从理论上研究了气体轴承副零件因加工过程中形成的几何形误差对气体静压圆柱轴承运动精度的影响,并且,对轴颈具有加工误差时气体静压圆柱轴承的运动精度进行了研究,给出了轴颈的几何形误差与轴承运动精度关系的表达式,为轴承运动精度的理论分析提供了可靠的依据。     

用金属基三维连续网状多孔陶瓷复合材料制作静压气体轴承的可行性研究

介绍了对金属基三维连续网状多孔陶瓷复合材料（MNCC）进行的透气性及用该材料制作静压气体轴承的试验。结果表明，制作的铸铁基高密度陶瓷网络的MNCC材料透气性良好，易于加工，只要进一步实现制作工艺的精确控制，用以制作气体轴承具有开发前景。     

平箔动压止推气体轴承的试验研究

本文提出了一种新型结构的箔片止推动压气体轴承，搭建了多功能止推轴承试验台，并主要针对其承载力性能进行了初步的试验研究，试验轴承的外径为φ38mm，内径为φ16mm，在11000r/min的转速下获得的最大轴向承载力为44.1N。     

微小型高速透平径向箔片动压气体轴承的研究

微小型高速透平膨胀机的发展对微小型动压气体轴承的开发提出迫切的要求,研制微小型动压气体轴承十分必要。在一台微小型高速透平膨胀机上对平箔型、弹性片支承型、鼓泡型3种不同的径向箔片气体轴承分别进行了研究。试验结果表明3种箔片轴承均能满足运行要求,通过比较发现,鼓泡型径向箔片气体轴承具有加工简单,运转稳定的特点。配合鼓泡型动压止推轴承,对全鼓泡型箔片轴承全动压透平膨胀机进行研究。初步试验最高转速可达22万r/min。     

Experimental Investigation of Friction and Electrical Characteristics of the Porous Bearings with Axial Grooves for Laser Scanner

The electrical and frictional properties of axially grooved oil-impregnated sintered-metal bearing (porous metal bearing) with varying loads and speeds were measured. The results were compared with the performance of bearings without grooves and conventionally used ball bearings. The test results showed that the frictional values of the porous bearings were lower than those of ungrooved bearings and ball bearings, and that the porous bearings operated in a full-hydrodynamic lubrication regime. The values of rating current, starting time and jitter revealed that the grooved-bearing had better electrical characteristics than the ungrooved bearing as well as the ball bearing. From the endurance tests on start-stop and continuous operating, it was confirmed that this bearing could be mass-produced for use in a laser scanner unit.     

Stability Analysis of Floating Ball Bearing

Conventional disk drive motors supported on ball bearings (BBs) cause nonrepeatable runout (NRRO) due to the surface imperfections on balls and raceways. NRRO is a source of track misregistration between head and disk that inhibits high track density in a hard disk drive. Fluid dynamic bearings with herringbone grooves either on the rotating or stationary surfaces are a suitable replacement for conventional ball bearings. Herringbone grooved bearings have considerably lower noise level than ball bearings and have better stability compared to plain journal bearings at concentric operating position. However, herringbone-grooved patterns are difficult to manufacture because groove depth is of the order of bearing clearance. The major limitation of the BBs is the direct contact between the rotating and stationary parts and also lack of damping effects. This present work attempts to overcome these drawbacks in BBs by eliminating the metal-to-metal contact using a layer of fluid film, and a theoretical analysis of stability characteristics of a floating BB is presented. Results indicate that there is an improvement in the stability of floating BB rotor systems with increase in outer to inner film clearance ratio (β) from 0.7 to 1.3, and with decrease in ratio of outer race radius to inner race radius (δ) from 3.0 to 1.2.     

Measurements of Compressibility Effects in Stepped Thrust Gas Film Bearings

Hydrodynamic gas film bearings are used for supporting high-speed, lightly loaded rotating machinery. Stepped-type gas film bearings are often used for such machinery because of theïr simple structure, high stability and load carrying capacity. This paper describes the measurements of compressibility effects on the static and dynamic characteristics of stepped thrust gas film bearings. In the experiments, the minimum film thickness, friction torque on the bearing surface and stiffness and damping coefficients of gas films are measured for a range of rotational speed from 10,000 rpm to 20,000 rpm under a constant stator mass and a fixed step height. The measured data are compared with the theoretical results and the gas film compressibility effects on the static and dynamic characteristics of the bearings are discussed. The experimental results agree well with the predicted results based on the compressible lubrication theory.     

The Role of Radial Clearance on the Performance of Foil Air Bearings

Load capacity tests were conducted to determine how radial clearance variations affect the load capacity coefficient of foil air bearings. Two Generation III foil air bearings with the same design but possessing different initial radial clearances were tested at room temperature against an as-ground PS304 coated journal operating at 30000 rpm. Increases in radial clearance were accomplished by reducing the journal's outside diameter via an in-place grinding system. From each load capacity test the bearing load capacity coefficient was calculated from the rule-of-thumb (ROT) model developed for foil air bearings.

The test results indicate that, in terms of the load capacity coefficient, radial clearance has a direct impact on the performance of the foil air bearing. Each test bearing exhibited an optimum radial clearance that resulted in a maximum load capacity coefficient. Relative to this optimum value are two separate operating regimes that are governed by different modes of failure. Bearings operating with radial clearances less than the optimum exhibit load capacity coefficients that are a strong function of radial clearance and are prone to a thermal runaway failure mechanism and bearing seizure. Conversely, a bearing operating with a radial clearance twice the optimum suffered only a 20% decline in its maximum load capacity coefficient and did not experience any thermal management problems. However, it is unknown to what degree these changes in radial clearance had on other performance parameters, such as the stiffness and damping properties of the bearings.     

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。     

轴向缝切向进气轴颈轴承稳定性的试验研究

本文设计了组合式及嵌入式轴向缝切向进气轴颈轴承,将其装配到与１５０Ｎｍ＾３／ｈ制氧机配套的中压透平膨胀机上进行试验,实测了不同设计参数下的轴承失稳转还,并分析了影响轴承失稳转速的各种因素。     

SPF复合自润滑轴承的设计与性能研究

讨论了用于自润滑系统中一种新型滑动轴承的设计与性能,较好地解决了自润滑轴承的材料选择,复合方式,多孔层的结构和自润滑层成分设计等问题。采用新设计可有效地提高自润滑轴承的承载能力、极限pv值、耐磨性和高温使用寿命。试验结果表明SPF复合自润滑滑动轴承的某些性能已超过DU轴承。     

Effect of Rolling Bearing Refurbishment and Restoration on Bearing Life and Reliability

For nearly four decades it has been a practice in commercial and military aircraft application that rolling-element bearings removed at maintenance or overhaul be reworked and returned to service. The work presented extends previously reported bearing life analysis to consider the depth (Z₄₅) to maximum shear stress (τ₄₅) on stressed volume removal and the effect of replacing the rolling elements with a new set. A simple algebraic relationship was established to determine the L₁₀ life of bearing races subject to bearing rework. Depending on the extent of rework and based on theoretical analysis, representative life factors for bearings subject to rework ranged from 0.87 to 0.99% of the lives of new bearings. Based on bearing endurance data, 92% of the bearing sets that would be subject to rework would result in L₁₀ lives equaling and/or exceeding that predicted for new bearings, with the remaining 8% having the potential to achieve the analytically predicted life of new bearings when one of the rings is replaced at rework. The potential savings from bearing rework varies from 53 to 82% that of new bearings depending on the cost, size, and complexity of the bearing.     

The possibility of evaluating turbo-set bearing misalignment defects on the basis of bearing trajectory features

This paper presents the results of computer simulation of bearing misalignment defects in a power turbogenerator. This malfunction is typical for great multi-rotor and multi-bearing rotating machines and very common in power turbo-sets. Necessary calculations were carried out by the computer code system MESWIR, developed and used at the IFFM in Gdansk for calculating dynamics of rotors supported on oil bearings. The results are presented in the form of a set of journal and bush trajectories of all turbo-set bearings. Our analysis focuses on the vibrational effects of displacing the two most vulnerable machine bearings in horizontal and vertical directions by the maximum acceptable range calculated with regard to bearing vibration criterion. This assumption required preliminary assessment of the maximum values for the permissible bearing dislocations. We show the relations between the attributes of the particular bearing trajectories and the bearing displacements in relation to their base design position. The shape and dimensions of bearing trajectories are interpreted based on the theory of hydrodynamic lubrication of oil bearings. It was shown that the relative journal trajectories and absolute bush trajectories carry much important information about the dynamic state of the machine, indicating also the way in which bearings are loaded. Therefore, trajectories can be a source of information about the position and direction of bearing misalignments. This article indicates the potential of using trajectory patterns for diagnosing misalignment defects in rotating machines and suggests including sets of trajectory patterns to the knowledge base of a machine diagnostic system.     

An Experimental Comparison of Two Steadily Loaded Plain Journal Bearings

A potentially powerful effect on the characteristics of plain journal bearings is local thermal deformation of the bearing surface. Although there are a few analyses that consider the effect, it is ignored by most journal bearing codes used by industry. There is also almost no experimental data in the literature that focuses on this effect. To generate such data, two identical, 101 mm dia., 57 mm long bearings—one fabricated from steel and one from bronze—have been tested in a precision journal bearing test rig. Comparisons between shaft displacement data for steady loading of the two bearings show that the deformations are important to consider.