A study of the dynamic behavior of a passive micro magnetic suspension motor
|關鍵字:||釹鐵硼;磁懸浮;磁浮軸承;微型馬達;被動式阻尼;NdFeB;Magnetic levitation;Magnetic bearing;Micro motor;Passive damping|
The goal of this dissertation was to investigate the dynamic behaviours and the related effects of a proposed passive magnetic bearing (MB) motor. The concept of the bearing used the repulsive magnetic force to levitate the rotor in the radial direction by utilizing the sintered magnet (N45) with high energy product. Not only a mathematical model for the MB was proposed, which can predict the dynamic characteristics of the developed motor, but also a design procedure for fabricating the prototype was introduced. The mathematical model and the prototype points out that the micro magnetic bearing motor can be carried out on the basis of the developed theory and experiments. Beside the basic gyroscopic effect and rotor unbalance effect were observed, the interesting effects including damping effect, bias-magnetic force effect, and scaled-down effect were discussed one by one. Regarding the damping effect, an innovative damping device consisting of a magnetic ring of high permeability and an annular rubber pad can apparently increase the anti-shock ability of the MB motor. Moreover, an approach of the vibration reduction utilizing an induced magnetic force was developed. In addition, a prototype of scaled-down MB motor (the outer magnet with an inner diameter of 5 mm, an outer diameter of 8 mm, and a height of 3.6 mm) was studied. Both the inner and outer part was comprised of a stack structure of high energy product magnet. These rings were arranged on the shaft above the PM of the rotor and the stator. From the experimental observation, the shaft can be rotated without any frictional contacts in radial direction. It shows that the micro magnetic bearing (MMB) demonstrates the lower friction torque loss in comparison with the conventional micro ball bearing (MBB). Moreover, the radial vibration of our device is 21 % lower than the conventional MBB type. The research mentioned above was focused on the motor type with radial air gap. Finally, the dissertation gave the pre-study report regarding a study of axial vibration for a flat-type motor (axial air gap). The results indicate that axial pre-load apparently affects the axial vibration of the motor, and this will be a valuable reference for the research which will be aimed to study the system with the MMB.
|Appears in Collections:||Thesis|
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