| 摘要 |
PURPOSE:To prevent generation of excessive attracting force of the electromagnet when attraction is completed by a method wherein a penetrating hole, a groove, etc., is provided in a movable core to make the width at the middle part to be narrowed substantially. CONSTITUTION:The penetrating hole 10 having the hole diameter D is formed at the middle part of the movable core 5 to make width at the middle part to be narrowed (B-D) substantially, and accordingly the quantity of magnetic flux is limited when attraction is completed, and action of excessive attracting force to the movable core 5 is prevented. By providing the penetrating hole 10, reduction of increase of magnetic flux according to approach of the movable core 5 to a core 3 up to the neighborhood of the saturated value can be attained. |
