PURPOSE: To provide an electromagnet of high sensitivity, by a method wherein magnetic flux generated by a coil and magnetic flux generated by a permanent magnet are independent of each other to constitute magnetic circuit, multiplying attractive force is produced to a movable block, and the magnetic flux generated by the coil does not pass through the permanent magnet.
CONSTITUTION: A polar electromagnet 1 is composed of a core block 2, a permanent magnet 4 and a movable block 5. At setting state magnetic flux c is produced by current I and coincides to magnetic flux m from the permanent magnet 4 in the flux direction passing through a left end portion 10a of a movable iron piece 10 and an end side 7a of core 7 thereby the multiplied attractive force is generated. Even if the current I flowing in the coil 3 is interrupted in this state, the movable block 5 remains to be held by the magnetic flux m. For transferring to the reset state, if the current flowing in the coil 3 is reversed the direction of magnetic flux c is reversed, thereby the movable block 5 is moved in the direction of reset state. In the reset state magnetic flux c generated by coil 3 coincides to magnetic flux m by the permanent magnet 4 in the direction passing between a left end portion 11a of a movable iron piece 11 and an end side 8a of a core 8.
MAENISHI KOUZOU
TSURUYOSHI KENICHI
HONDA SUEAKI
SANO TAKEZOU
KISHIMOTO SHIYUUICHI
