| 摘要 |
PURPOSE:To increase the attracting force of an electromagnet and the separating speed thereof by employing two or more types of ferromagnetic materials of different properties in combination as a magnetic core. CONSTITUTION:Ferromagnetic materials having different properties such as saturated magnetic flux density, corcive force and residual magnetic flux density and so forth are composed in mixture, thereby forming a magnetic core. For example, a permalloy 45 having large attracting force and permalloy 78 having large separating velocity are employed. permalloy 45 is used at 3a, 3c, 5a, 5c and the permalloy 78 are used at 3b, 5b, thereby forming an armature 3 and a yoke 5. Thus, the attracting force and separating velocity of the electromagnet are increased and are utilized for the shutter of a camera or the like. Further, ferromagnetic materials having different hardnesses are combined, and harder material is used for a yoke and softer material is used for the contacts 50b, 51b of the armature, thereby enhancing the contacting strength. |
