| 摘要 |
<p>An electromagnetic device, such as a relay, having a stationary core (13) and a movable armature (24), each having three pole faces (16, 16 min , 17; 29, 30, 28), forms a magnetic circuit having three substantially parallel legs when the core (13) and the armature (24) are brought together. The centre leg, but not the two side legs, of the magnetic circuit includes a region of decreased magnetic permeability which separates the centre pole faces (17, 28) and which is constituted by an air gap and a non-magnetic coating (49) on the centre pole face (28) of the armature (24), which coating (49) is more resistant to wear than the material of the uncoated pole faces forming the two side legs of the magnetic circuit. …<??>The air gap and coating between the centre pole faces aids separation of the core (13) and armature (24) whilst avoiding excessive magnetic reluctance which would impair closing movement of the core (13) and armature (24).</p> |
