Structural Design And Electromagnetic Analysis Of Adjustable Speed Asynchronous Disk Magnetic Coupling

Asynchronous disc magnetic coupling is a new type of magnetic device which is applied to electromagnetic induction principle. Because of its simple structure, achieving the motor and load non-contact power transmission, the damage problems of mechanical coupling itself and the surrounding parts caused by direct contact withstanding high vibration are solved effectively. Achieving the soft start the motor speed functions can be used in mining, petrochemical, marine, paper, steel industry, irrigation project areas of transmission and etc widely. In this paper, a new type of adjustable speed asynchronous disk magnetic coupling was researched and development designed independently. As it had simple structure, transfer torque, and good speed control function, so it had a good value in engineering and offers reference for domestic researches of disc asynchronous magnetic coupling.Firstly, a new type of adjustable speed asynchronous disk magnetic coupling was advanced with its structure and timing device was designed. According to the basic principles of magnetic circuit and work pattern of the coupling, the paper made analysis of magnetic coupling of the main magnetic circuit and magnetic flux leakage, calculated equivalently by equivalent magnetic circuit method, and provided a basis for magnetic circuit analysis of the similar magnetic coupling. By certain assumptions, the solving model of static magnetic field and induced magnetic field was established and the analytical expression of magnetic induction of permanent magnet and the induced current within regions in the coupling was derived. At the same time, taking magnetic field generated within their respective air gap by superposition and the analytical expression under the load air-gap magnetic field was obtained. This paper had calculated the induced currents on the driven plate, analyzed the magnetic coupling relationship in the corresponding electromagnetic, and provided guidance for the initial calculation and design. For the sake of reflecting magnetic field distribution of the magnetic coupling, this paper made use of finite element analysis software ANSOFT to take numerical analysis on the three-dimensional magnetic field of the magnetic coupling under the static and transient state. The distribution of magnetic flux density and induced current and the curves changed over time of magnetic coupling torque under load conditions, power loss and performance parameters such as axial force were obtained. Meantime, this paper conducted simulation analysis of the key parameters of magnetic coupling torque.Through finite element analysis, the magnetic circuit in the magnetic circuit under static and transient was consistent. But the magnetic field under transient was stronger than the static. And indicated that the induced current strengthened the permanent magnet magnetic field; the results of the coupling torque, power losses, axial force curves reflected the magnetic coupling process up and running accurately. And it provided a theoretical basis for reducing the torque ripple and improving start torque.Analysis on the effect of different parameters on the torque of magnetic coupling indicated that: Increasing the air gap would reduce the coupling of the torque; Increasing the thickness of permanent magnet could increase the torque, but the torque could not increase infinitely. When permanent magnet thickness increased to a certain degree, torque curve slope would become smaller and slower increasing; In a certain range, torque would increase with the increasing of coupling poles, driven disk slot number, groove depth and active speed. But after increasing to some extent, torque would reduce with the keeping on increasing of coupling poles, driven disk slot number, groove depth and active speed. And the results provided the basis for the optimization of magnetic coupling.