| 摘要 |
PURPOSE:To stably actuate an electromagnetic clutch for changing the ratio between the rotational speed of an engine and that of an accessory, by concentrically arranging two ring-like movable pieces in the clutch and by attracting the movable pieces such that a plurality of electromagnets each composed of a coil which does not surround the centers of the respective movable pieces are selectively energized. CONSTITUTION:First second movable pieces 2, 4 are concentrically arranged on a V-shaped pulley 1 while a plurality of electromagnetic 16 (16a, 16b) are disposed in an electromagnetic clutch stator 12 in an accessory casing 13 on two circumferences. When the electromagnet 16A is energized, the second movable piece 4 is alone attracted. At this time the magnetic force lines generated by the electromagnet 16A pass from an inner iron core 16b through the second movable piece 4 and an outer iron core 16a and are closed so that it is possible to prevent the magnetic force lines from leaking. Since no magnetic flux externally leaks when the electromagnets 16 are energized, as mentioned above, it is possible to stably engage and disengage the clutch.
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