| 摘要 |
PURPOSE:To prevent dust from penetration and facilitate smooth and high speed operation of a movable core for a long life by a method wherein an operation bar is fixed to the center of the movable core and a plurality of ventilation paths are provided along an axis of the movable core. CONSTITUTION:Bearings 5, 6 are pushed into a case 11 and the case 11 is tightly sealed up. A coil 2, a movable core 3 which is held by the bearings 6 and a cushon material are contained in the case 11 and an operation bar 4 is fixed to the center of the movable core 3 and held by the bearing 5. A plurality of ventilation paths 12 are provided to the movable core 3 along its axis. With this composition, penetration of dust is prevented so that the movable core 3 can be operated smoothly for a long life and, as the air is ventilated by the ventilation paths 12 provided to the movable core 3, the movable core 3 can be operated with a high speed. |
