| 摘要 |
An electromagnet has a pot-shaped enclosure having a cylindrical portion and consisting of magnetizable material, and an elongated guide means which consists of non-magnetizable material and extends substantially centrally of the pot-shaped enclosure. A winding is mounted in the enclosure. An armature is slidably mounted for movement lengthwise on the guide means in response to changes in condition of energization of the winding. The enclosure has a pole piece which defines an internal surface and the armature has an external surface defining, with said internal surface, a clearance whose width remains substantially unchanged while the armature moves with reference to the guide means. The enclosure and armature have conical pole faces which define a conical gap which varies in response to movement of the armature with reference to the guide means. |
