The Research And Design Of Nested Permanent Magnet Magic Ring

There is a kind of special permanent magnetic mechanism—nested permanent magnet magic ring which is composed of two concentric magic rings, each of them is made up of permanent magnet segments with different magnetization directions. The magnetic conductivity of permanent-magnet material approaches to the air, so the magnetic field produced by the outer ring may pass through the inner ring free, and the central magnetic field is a vector superimposition of two magnetic fields. If we design the magic ring properly, a magnetic flux density level several times as much as the remanence of permanent magnet material can be achieved, and realized continuously to change from zero to the maximum value by the synchronized contra-rotation of the inner ring and the outer ring.It is complicated of the structure and the work process of nested magic ring, the inner ring must withstand certain degree degaussing field function of the outer ring. The permanent magnet blocks interact with the move of their position, and abnormal magnetization including local saturation, local demagnetization and rotational magnetization easily emerge. The work point of magnetic field might achieve arbitrary quadrant of hysteresis loop, so the ideal nested magic ring is unable to work normally under the theory value. Though some foreign researchers produced some nested magic ring mechanisms, they are not comprehensively simulates the magnetic field distribution and the magnetization condition in the assembly and the work process, and the value of magnetic field is low.Based on analysis of basic structure and work process, one kind of improved nested magic ring is proposed. The material of the inner ring has a higher coercive force, and the outer ring has a bigger remanence. The improvement nested magic ring not only may have bigger field intensity under a smaller volume, but also better reduce the magnetic field component of x axis.Combining the vector Preisach hysteresis model and finite element analysis, a dynamic magnetic field analysis is implemented for nested magic ring in the process of assembling and working. Through adding the certain shape of the soft magnetic material or the permanent-magnet material in the center air gap, two kind of special enhanced nested magic ring are designed. It may choose the appropriate structure according to different needs.