电磁轴承-无轴承电机系统在转子主动控制的应用研究

主动磁轴承借助电磁力来控制转子的振动,无轴承电机在实现转矩控制的同时实现电机的悬浮控制。本文在对永磁偏置三自由度电磁轴承和两自由度无轴承电机的磁悬浮机理一般性描述的基础上,分析了其产生的悬浮控制力。并以转子电磁振动为研究对象,结合电磁轴承和无轴承电机的特点,提出利用一种新型的五自由度磁悬浮异步电机作为执行机构对转子电磁振动进行主动控制,实现了转子系统稳定工作。此系统可以有两方面的应用,既可以用做转子的支承,也可以用做转子振动主动控制的增稳。     

一种新型的电磁轴承系统辅助轴承的设计

采用了一种应用于电磁轴承系统的,用电磁铁控制的可移动新型辅助轴承结构。介绍了电磁轴承的系统构成、工作原理,报告了辅助轴承的使用现况,具体说明了新型辅助轴承主要部件的设计过程。     

转子──电磁轴承系统性能研究

本文介绍了电磁轴承的特性及其研究发展状况，给出了五自由度电磁轴承──转子系统模型，阐述了使转子稳定悬浮和运转的基本控制规律，分析了转子在电磁轴承中运转特性，并给出了转子稳定运转的实验记录曲线。     

电磁轴承中电磁场的有限元分析

在分析以往电磁轴承结构设计及计算方法的基础上 ,论述了电磁轴承电磁场的有限元分析方法 ,建立了电磁轴承的有限元模型 ,编制了电磁轴承电磁场有限元分析软件 ,实现了可视化 ,并给出了实例分析结果     

电磁轴承刚度与阻尼特性的非线性研究

刚度与阻尼特性是电磁轴承重要的性能指标。对电磁轴承刚度与阻尼特性进行了非线性研究,建立了储能飞轮转子系统径向电磁轴承的非线性模型,推导了非线性情况下电磁轴承刚度与阻尼的计算公式,分析了电磁轴承刚度与阻尼的非线性特性,以及控制因数对刚度与阻尼的影响。研究结果表明,增大比例因数,可以使电磁轴承的刚度减小,达到正刚度时的转子位移范围同时减小。通过研究同时确认,电磁轴承阻尼受控制因数的影响较小。     

一种新型轴承—永磁体磁力轴承

一种新型轴承——永磁体磁力轴承南京工业学校（２１０００８）赵家文一、永磁体磁力轴承的原理目前有关磁力悬浮轴承的论述一般均指电磁磁力悬浮轴承，它是八十年代开发的新技术，首先被用于宇宙地球观测卫星，随后逐渐开发转向民用。迄今，电磁磁力悬浮轴承已成功地应用...     

电磁轴承力学特性的有限元分析

利用有限元法对轴向电磁轴承的磁场分布进行了数值模拟分析，并通过对某一实际电磁轴承的轴向轴承磁场分布及电磁力的分析计算，得出了轴向电磁轴承的承载力工作范围和静态刚度曲线，所得结果可作为轴向电磁轴承实际设计的准则。     

磁通方向变化对电磁轴承径向耦合动特性的影响

电磁轴承轴颈径向的微小扰动Δx或Δy除了影响轴承气隙长度外,同时还会影响轴承的磁通方向,此时,如果仅考虑轴承气隙变化,电磁轴承径向不会产生耦合;如果进一步考虑轴承磁通方向的变化,将会改变轴承磁力在径向的分配,从而导致轴承产生径向耦合。本文首先分析了轴颈径向扰动对电磁轴承磁通方向的影响,然后,在同时考虑气隙和磁通方向变化的基础上建立了电磁轴承径向刚度的计算模型,最后给出了轴承磁极耦合刚度的数值计算结果,并进行了相应的分析。     

电磁轴承的工业应用设计

按以前的设计方法,不能保证转子在任何位置都能浮起,且轴承温升过大,可靠性差,本文提出的设计方法,解决了电磁轴承在工业中的实用问题。以径向和推力电磁轴承为例,介绍了轴承结构参数的设计方法,并对不同设计方法的所得结果进行了对比分析。     

电磁轴承开关功放设计

讨论了电磁轴承开关描放各主要参数的方法以及这些参数和电磁轴承系统的关系，提出了设计中的一般原则和注意事项，针中具体的做作制作，结果令人满意。     

Spatially Sampled Pressure Profile Measurements in Externally Pressurized Gas Journal Bearings

Abstract

Externally pressurized gas journal bearings (EPGJBs) are widely adopted to support high-speed rotors. This article presents novel experimental benchmark test data that enable EPGJB model validation. Axial and circumferential pressure profile measurements are presented for a 40-mm-diameter annular restrictor EPGJB operating at speeds up to 25?krpm. The corresponding rotor position, air mass flow rate, and load capacity are also measured. The effects of supply pressure, rotational speed, and load on the measured variables are presented. The measurements are in good agreement with numerical model computations. The cases in which the model deviates from the measured data are discussed in terms of compressible flow theory.     

弹性支承箔片动压气体径向轴承的实验研究

对新型结构弹性支承箔片动压气体径向轴承进行试验研究,在高速透平膨胀机(主轴轴径D=25.0mm、转子总长l=250.5mm、转子质量Gm=891g、额定工作转速10.64×104r/min)上达到了转子转速14.8×104r/min、超速40%的良好试验效果。对这种弹性支承箔片动压气体径向轴承的振动特性和稳定性进行试验研究。结果表明,该轴承具有优良的动态特性与稳定性,能有效抑制高速自激涡动的发展,在正确选择结构参数和表面处理方法后,有望替代目前在高速透平机械中广泛应用的静压气体轴承。     

Stability of a rigid rotor in turbulent hybrid porous journal bearings

Stability characteristics of hybrid porous journal bearings with a turbulent fluid film have been investigated theoretically following Constantinescu's turbulent lubrication theory. The stability curves have been drawn for different Re, eccentricity ratios, slenderness ratios and bearing speed parameters. In the absence of any experimental data, laminar flow results obtained by this analysis have been compared and found to be in excellent agreement with the previous results. It is observed that turbulence deteriorates the stability of the rotor and for better performance the value of the bearing feeding parameter, β, should be kept small.     

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。     

Properties and prospective applications of ultra thin layered rubber-metal laminates for limited travel bearings

Limited and/or oscillating motions represent the most severe operating conditions for conventional bearings, both sliding and antifriction. Thin-layered rubber-metal laminates seem to be ideal substitutes for conventional bearings for oscillating motions. This paper descirbes experimental investigations of the compression and shear properties of flat and spherical laminates. The very high compression stiffness and strength of the laminates are accompanied by low shear stiffness. Strong non-linearity of the hardening type in compression is accompanied by weak non-linearity of the softening type in shear. Substantial non-linearity in compression starts as early as at relative compression 0.001. Applications of thin-layered laminates for compensating couplings, U-joints, gears, vibration isolators and impact cushioning in joints of mechanisms are described. Expressions have been derived for efficiency of couplings and joints equipped with laminates     

滚动轴承和滚珠丝扛中润滑油脂的外溅性

滚动轴承或直线运动轴承中的润滑油脂，可能飞溅出颗粒，粘附在液晶制品或硬盘上，导致设备失效。所以，这种设备轴承所使用的润滑油脂尽可能降低飞溅性。但低飞溅性的润滑油脂可能带来耐磨性、噪声、阻力矩等问题。因此，我们需要一种油脂，它既具有低飞溅性，又有较高的性能和使用寿命。为了开发低飞溅性的油脂，作者研究了油脂成分和飞溅性的关系。一些数据下面会提到。飞溅颗粒的多少和基油成分有很大关系，例如，润滑油脂基油是矿物油或合成碳化氢油，它们极性低，飞溅颗粒少；相反，如果是酯油，它的极性高，飞溅性也高。飞溅颗粒的多少也取决于增稠剂的类型和含量，例如浓的润滑油脂的飞溅数量少。作者证实了飞溅出来的颗粒不仅有基油颗粒，而且有细小的油脂颗粒，油脂颗粒的直径范围在０．１１ 到０．２μｍ 。     

Optimisation of slot entry hybrid gas bearings

Optimisation of hybrid gas bearings is considered from the view-point of minimum total power dissipation on load per unit power of the bearing. The optimisation techniques presented in this paper are derived on a varyin clearance basis. The selection of bearing design parameters for the optimum condition varies according to the restraints and constraints of the design. Therefore, the bearing design parameters are related and selected in order to achieve the optimum performance. The optimum design condition for minimum total power dissipation occurs when the friction power is three times the pumping power (K = 3).     

Hybrid journal bearings with particular reference to hole-entry configurations

There is a spectrum of pressure-fed journal bearings ranging from the purely hydrostatic bearing characteristics, ie zero speed operation, to the purely hydrodynamic bearing characteristics which depend completely on speed. Between these two extremes, hybrid bearing characteristics rely on mixed modes of external pressurisation and speed-dependent pressurisation. Large high speed hydrodynamic bearings require the lubricant to be pumped under pressure for temperature control. It is therefore attractive to use this external source of pressure to enhance the start-up performance by reducing wear and improving stability. Hybrid bearings offer the possibility of improving on both the zero-speed characteristics of hydrostatic bearings and on the whole range of speed characteristics of hydrodynamic bearings. It is concluded that hole-entry bearings may be particularly effective when compared with other bearing configurations for good load support and low energy consumption, when used in any of the four modes of operation including: zero-speed hydrostatic mode; high-speed hydrodynamic mode; zero and high-speed hybrid mode; and jacking mode where areas are pressurised for start-up. A modification to the procedure for solving the Reynolds equation is introduced to cope with cavitated regions. The technique presented for solving the bearing pressures and cavitation boundaries is efficient and has relevance to any type of liquid film bearing     

Conical whirl instability of turbulent flow hybrid porous journal bearings

An analysis of conical whirl instability of an unloaded rigid rotor supported in a turbulent flow hybrid porous journal bearing has been presented, following Constantinescu's turbulent lubrication theory. The effect of bearing feeding parameter (β), Reynolds number (Re), ratio of wall thickness to journal radius (H/R) and anisotropy of porous material on the stability of rotor-bearing system has been investigated. It is observed that higher values of β gives better stability and higher stability is predicted if the porous bush is considered to be isotropic.     

Experimental Investigation of Laser Surface Textured Parallel Thrust Bearings

Performance enhancements by laser surface texturing (LST) of parallel-thrust bearings is experimentally investigated. Test results are compared with a theoretical model and good correlation is found over the relevant operating conditions. A comparison of the performance of unidirectional and bi-directional partial-LST bearings with that of a baseline, untextured bearing is presented showing the benefits of LST in terms of increased clearance and reduced friction.