This paper first proposes a magnetic lead screw which is comprised of a conventional steel lead screw and a magnetic nut. The nut is made from a helically-magnetized cylindrical permanent magnet and an external steel cover. A driving force from the screw to the nut is transmitted through the magnetic coupling without mechanical contact. So the magnetic lead screw can be used in vacuum, does not make noise and vibration, and is free from lubrication problem. However, the axial stiffness and maximum carrying load of the magnetic lead screws are smaller than those of ordinary lead screws. Experimental magnetic lead screws are made and it is proved that experimental results of the carrying load and stiffness in the axial direction agree well with simulated ones using the FEM models. It is also clarified that the thread depth and fiat width of lead screw affect the carrying load of the mechanism.
