The Magnetic Fields Of Electromechanical Integrated Toroidal Drive

Electromechanical integrated toroidal transmission is a new composite drive based on toroidal drive, which integrated mechanism with electromagnetism and control. By the coupling of magnetic fields, the transition and output of motion and power are completed; therefore, it is important for theoretic analysis and application of the drive system studying drive mechanism and related other problems of electromechanical integrated transmission. This paper investigated thoroughly the principle of magnetic mesh, magnetic drive, calculation of the component magnetic field distribution, the coupling effect of magnetic field and the design of model machine for the electromechanical integrated mechanism.Based on electromagnetic theory, basic equations of the magnetic fields are given about magnetometive scalar and vector under three kinds of coordinates. Based on toroidal drive, magnetic meshing principle of electromechanical integrated toroidal drive is analyzed by combining magnetic mesh characteristic; movement relations of components are presented. The correct meshing conditions and the meshing tooth number formulas of single tooth and multi teeth mesh for the drive are given. The forces for the transmission are analyzed as well. The magnetic circuits of the stator, worm, planet and the total transmission are analyzed, which offer theory basis for magnetic field computation.The worm magnetic field of the drive is analyzed and calculated. The calculation models of single-phase and tri-phase fields are constructed, the formulas of the 3-D magnetic field for single-phase wires are derived, and the equations of the total magnetic field are obtained by the superposition principle, the decomposing results of the magnetic field under different coordinates are given. The magnetic field of the worm windings is calculated, which shows the distribution of the worm magnetic field.From the theory of permanent magnet, the planet tooth magnetic field and total planet magnetic field for the electromechanical integrated toroidal drive are studied, the model of magnetic field distribution for cylinder magnet tooth is presented, the formula of spacial field distribution for permanent magnet teeth is derived, the transformation matrix of coordinates between planet tooth and planet is given, the magnetic field formulas of the whole planet is obtained by the principle of coordinate transformation, the distribution of the magnetic field at axis and different axial sections are analyzed. The distribution of the space magnetic field is obtained; the correctness of the result is validated by FEM simulation.The stator permanent magnetic field of the electromechanical integrated toroidal drive are calculated and analyzed by finite element method. Finite element model of the stator is presented, corresponding conditional variations questions of constant magnetic field are deduced by variation principle from partial differential equations of constant magnetic field, and three steps of variation questions are illustrated. The key problems in finite element method calculation of permanent magnetic field of the drive are analyzed in detail. The whole and partial magnetic fields of the stator are calculated by finite element software, and the distributions of the permanent magnetic field of the stator are obtained.The mechanical models of electromechanical integrated toroidal drive with magnetic meshing between stator and planet or between worm and planet are established on the base of electromagnetic theory. Equivalent current model of permanent magnetic body of planet tooth is given. The calculating formulas of the magnetic field force between stator and planet or between worm and planet are deduced. The calculating formulas of the output torque of the drive are deduced as well. The output torque of the drive is calculated and analyzed; the influence factors and their influence on output torque are summarized. It offers the design base of the drive.The principle tests of the drive are done. The results validate correctness of theory analysis.