| 摘要 |
PURPOSE:To improve magnetic efficiency by removing the joint of a yoke in a type wherein the contact and the separation of the yoke and an armature are operated in the air-core of a coil. CONSTITUTION:When a coil 1 is excited, magnetic flux phi flows from a yoke 4 to the long piece 4b of the yoke, to an armature 5, to a gap, to the short piece 4a of the yoke and to the yoke 4, the end 5b of the armature 5 is attracted to the short piece 4a of the yoke against the spring forces of a movable contact 17 and a return spring 6, the armature 5 is shifted to a contact position X2 shown by a full line and consequently, a contact point is closed. In this state, if the coil 1 is demagnetized again, the armature 5 is separated from the short piece 4a of the yoke by the spring forces of the movable contact 17 and the return spring 6, the armature 5 is returned to a separation position X1 shown by a broken line and consequently, the contact point is opened. In this way, the end 5b of the armature 5 which operates contact and separation (attraction and release) and the short piece 4a of the yoke are positioned in the air-core 2 of the coil 1 so not only the leakage of the magnetic flux is reduced but also magnetic reluctance can be reduced and magnetic efficiency is improved since the joint of the yoke conventionally existing is removed.
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