JPS6482607A - Electromagnet device - Google Patents

Abstract

PURPOSE:To decrease power consumption and to lower manufacturing cost, by determining a position of a recess such that a permanent magnet is apart from the recess when an armature is stabilized by the permanent magnet and a return spring and the permanent magnet is faced with the recess when the armature is actuated by excitation of a coil. CONSTITUTION:Position of a recess 9d is determined such that a permanent magnet 5 is away from the recess 9d when an armature 2 is stabilized by the permanent magnet 5 and a return spring 15, and the permanent magnet 5 is opposed to the recess 9d when the armature 2 is actuated by excitation of a coil 1. If the armature 2 is in the returned state, the coil 1 is not excited and magnetic flux generated by the permanent magnet 5 flows through a path phi1. When current is supplied to the coil 1 in the same direction to that of magnetic flux of a path phi1 flowing across a gap G4, the magnetic flux passes through a path phi2 and the recess 9d is opposed to the pole N of the permanent magnet 5 as the armature 2 is moved. Thereby, a magnetic circuit whose magnetic force is provided by the permanent magnet 5 is opened. In this manner, the gaps G1-G4 are closed and a closed magnetic loop not passing the permanent magnet 5 is formed.