| 摘要 |
PURPOSE:To reduce the reluctance of a magnetic circuit and to increase the attraction force of an armature by making the face of the armature touch the end surface of a yoke at the position where the free end of the armature is separated from an electromagnet. CONSTITUTION:When a coil 12 has no current, the free end 10 of an armature 11 is separated from an iron core 14 by a restoring spring and a face 6 touches an end surface 5. When the current flows in the coil 12 in this state, magnetic flux PHI flows, e.g., in the direction shown by an arrow and the free end 10 of the armature 11 is attracted by the iron core 14 of an electromagnet 1 but no magnetic leakage exists and the magnetic efficiency of a magnetic circuit is good since the end surface 5 of a yoke 4 touches the face 6 of the armature 11. Since part of the magnetic flux PHI flows from a side surface 7 to a branch piece 8 in addition to the attraction force F1 of the iron core 14 to the free end 10, the branch piece 8 is attracted by attraction force F2 and the total force affecting the armature 11 is a resultant force F1 + F2.
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