| 摘要 |
<p>PURPOSE:To improve magnetic efficiency by forming a core cutting a drawn material. CONSTITUTION:A core 1 is a magnetic material such as electromagnetic soft iron. A hoop material formed to an approximately U-shaped cross section by drawing by a central piece 1e and both projection pieces 1a, 1b projecting at both end parts of the central piece 1e is cut to a specified thickness. Thereby, edge faces of both projection pieces 1a, 1b are formed to pole faces 1c, 1d. Accordingly, a pole face 4d is not a punched breaking face and is flat, has good positioning accuracy, and does not cause the deterioration of magnetic characteristic due to bending processing. Therefore, by using the device, it is possible to make a winding space of a coil 2 larger than that of a plane-like one without deteriorating attraction force and its attraction holding power in comparison with a plane-like one, thus improving magnetic efficiency as much.</p> |
