A new type of axial-flux magnetic lead screw with inherent spring characteristic

Magnetic Lead Screw (MLS) can transfer slow linear motion into fast rotary motion offering much higher force density than that of traditional linear permanent magnet machines. It has been developed for ocean wave energy harvester and active damper for electrical vehicles. In this paper, a new type of MLS is proposed, where all the permanent magnets of the rotor and translator are magnetized along the axial direction and it utilizes the propelling force between two opposite magnetic polarity poles for driving. It is a new topology for realizing MLS. The rotor and translator magnets can be made in the same shape reducing the manufacturing cost while maintaining good force density. In addition, it has another advantage of inherent spring characteristic that is preferred for e.g. working under resonance condition for achieving the best system efficiency.