Rotordynamics of a Trans-Rotary Magnetic Gear Rotor
Trans-Rotary Magnetic Gear (TROMAG) has recently been introduced as a reliable and efficient way of converting low-speed, high-force translation into high-speed, low-torque rotation, or vice versa. The gear can be used in any high force linear motion application; specifically, it would be a strong contender for wave energy harvesting. The TROMAG consists of two main parts: a rotor and a translator, both of which are formed by furnishing tubular ferromagnetic iron cores with helically-disposed permanent magnets. In this paper, the dynamics of the rotor is studied by employing the Finite Element Method (FEM) and using a simplified model where a flexible rotor is spinning on the flexible isotropic bearings. The rotor system has non-idealities that may excite the system to vibrate. In addition, the non-idealities in geometry cause uneven magnetic pulling force that is considered as an external force. The transient response of the rotor-bearing system is studied by varying the eccentricity of the rotor with respect to the translator. The vibration characteristics of the rotor-bearing system of the TROMAG are evaluated and presented in this paper.