Magnetic switch capable of performing normal detection for a long period of time

Abstract

A magnetic switch hardly affected by an external magnetic field even if a cheap magnet is used and capable of performing magnetic detection for a long period of time is provided. A first magnetic path L and a second magnetic path L in which a stationary rail and a movable rail lead magnetic fluxes are formed in a non-shielding state where magnetism shielding is not interposed in a gap G between a magnet M and a Hall element H to secure the number of magnetic fluxes that pass through the Hall element H. Therefore, it is not necessary to use a costly rare earth magnet having a large number of generated magnetic fluxes. In n shielding state where the magnetism shielding is interposed in the gap G, the first magnetic path L is shielded. As a result, the number of magnetic fluxes that pass through the Hall element H is almost zero. Since the magnet M and the Hall element H are covered with the stationary rail and the movable rail , the magnetic switch is hardly affected by the external magnetic field.