| 摘要 |
PURPOSE:To increase the magnetic attractive force produced by a solenoid, by forming a plurality of gaps where a plunger and a yoke face with a small clearance, at different positions axially and radially of the plunger. CONSTITUTION:When exciting current is supplied to a solenoid 31 in the state that a plunger 26 is located at its lowermost position, magnetic flux is produced in a magnetic path 45 and the plunger 26 is attracted by the yoke 32. Here, since three gaps 41a, 41b, 41c are formed almost in parallel with the magnetic path 45, the magnetic resistance of the magnetic path 45 can be reduced to an extremely small value and the magnetic flux density in the magnetic path 45 can be increased to a great extent. When the plunger 26 is displaced, the magnetic resistance is increased at the three positions of the gaps 41a, 41b, 41c and the permeance increasing rate of the magnetic path 45 to the movement of the plunger 26 is also increased. Therefore, it is enabled to move the plunger 26 by a small solenoid with a low power consumption. |
