| 摘要 |
A pole piece (14a) of the movable core (12) moves in an air gap (25a) between external (61) and internal (16) pole pieces. A pole flange (14b) of the same core (12) moves in an air gap (25b) between a portion (30b) of the external pole piece (61) and a magnetic lobe (36) which is in contact with this latter. A permanent return magnet (17) is disposed between the internal (16) and external (61) pole pieces. The magnet (17), the internal pole piece (16) and the lobe (36) are maintained in a cage (60) of plastic material snap fastened by hooks (78, 80) on the external pole piece (61). Three cross pieces (75, 76, 77) connecting two longitudinal walls of the cage to each other, suitably separate the different magnetic components. The force of attraction of the magnet (17) prevents the pole pieces (16, 61) from leaving it. |
