The Static Stiffness Measurement Of Disk-Shaped Hybrid Magnetic Bearings

With the rapid development of magnetic levitation technology, the magnetic levitation technology's application seeped to each life domain. While the magnetic bearing plays a great important role on maglev technology . Due to its no mechanical wear, low power consumption, low noise, long life, no lubrication, no oil pollution and other advantages, it's especially applicable to special environment like high-speed, vacuum, ultra-clean, and so on. It can be used in he field of machine machining , aerospace, vacuum techniques , turbo machinery , identification and testing equipment in rotor dynamics and so on . It is recognized as a very promising new type bearing.The Hybrid Magnetic Bearing studied in this paper is improved on traditional magnetic bearing . It can be applied broadly in new high-tech fields like bearing-less motor and artificial heart pump ,due to its simple structure, small size of axial direction, the carrying ability of axial loads and radial loads meanwhile, and other characteristics. It is greatly focused on by domestic and overseas Experts and scholars. However, whatever studies on bearings that are designed on any kind of theory, they are the studies on the stiffness property and the damping characteristic.This paper first introduces the disk-shaped hybrid magnetic bearing that is studied on the subject, and defines its static stiffness. Establish the Static mechanical model and the static radial stiffness model via basic Electromagnetic theory——the force and the stiffness are represented by mixed polynomial of the stator ampere-turn and the Relative displacement between stator and rotor with unknown coefficients, and then unknown coefficients will be soluted by the measuring displacement, anpere-turn and force, and then get the static radial stiffness of the magnetic bearing.Secondly , designs a high precision equipment that can measure the stiffness of the disk-shaped hybrid magnetic bearing on any direction without limitation of critical point and supplies a method according to this equipment.Finally, presents measurement results of the permanent magnetic field and the X-axis static radial stiffness function of the disk-shaped hybrid magnetic bearing based on the model.