| 摘要 |
PROBLEM TO BE SOLVED: To enable a shutter unit mounted on a digital single-lens reflex camera etc., to secure a magnetic attracting force which is strong enough not to make an armature fall from a yoke as a reaction when a mechanical inhibiting force of a driving lever is removed without altering the constitution of a conventional shutter unit. SOLUTION: A projection part 9 is provided to make the center portion of the armature 5 thick, and a shoulder portion of the projection part 9 has a slope in a direction of adsorption by the armature 5 and two magnetic poles 1a and 1b of yoke 1. Consequently, magnetic flux flows to the projection part 9 to reduce magnetic saturation occurring to the center portion of the armature 5, and the area of confrontation between the magnetic poles 1a and 1b of the yoke 1 and the armature 5 in an adsorption direction increases to pass more magnetic flux, thereby the armature 5 obtains a larger adsorptive power. Here, the projection part 9 is provided in a vacant area of the armature 5 between the magnetic poles 1a and 1b of the yoke 1, so the constitution of the shutter unit is not altered. COPYRIGHT: (C)2007,JPO&INPIT
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