Torques for electromechanical integrating toroidal drive

In this study, an electromechanical integrating toroidal drive is proposed and its operating principle is introduced. The equations of electromechanical coupled force and the rotor torque for the drive are given by means of electromagnetic theory and mechanical principle. The influenced factors of the rotor torque are analysed and their influences are obtained. There are periodic changes in the rotor torque and the change mainly depends on the tooth number of planet. The changes of the rotor torque along with mechanical and electric parameters of the drive and the limit-driving torque of the drive are presented. The limit driving torque is influenced by rotating angle of the planet and other factors. The minimum limit value decides the load-carrying ability of the drive. The equal-limit torque conditions between planet-worm and planet-stator are discussed. In order to obtain the equal-limit torque, a deterministic relation should be met among the current of the worm, the magnetic induction intensity of the permanent magnet stator, and the airgap thickness.