| 摘要 |
<p>PURPOSE:To prevent an attractive force of a solenoid from being reduced hardly even when a movement distance becomes large by a method wherein two or more magnetic substances are arranged one after another from the inside of a hollow iron core to the other end side of an excitation coil via a magnetic reluctance. CONSTITUTION:Two or more spherical magnetic substances 18 are arranged to be adjacent to one another in an axis core position of a bobbin 12; one end of the arranged spherical magnetic substances 18 is inserted into a hollow iron core 15; the other end comes into contact with a magnetic yoke 14. The spherical magnetic substances 18 are put in and inserted into a nonmagnetic pipe 19. When a selfholding type is adopted, a permanent magnet 21 is fixed to the upper part of the nonmagnetic pipe 19 coming into contact with the magnetic yoke 14. Magnetic flux generated when an electric current flows to an excitation coil 11 flows from an inner end of the hollow iron core 15 to the side of the magnetic substances 18 on the side of the permanent magnet 21; the hollow iron core 15 is attracted to the inside of the excitation coil 11. Even when the electric current to the excitation coil 11 is cut off in a state that the hollow iron core 15 is brought into contact with the permanent magnet 21, the hollow iron core 15 is attached to the permanent magnet 21 and becomes a self-holding state. By this setup, even when a movement distance of the iron core becomes large, a self- holding force is never reduced.</p> |
