| 摘要 |
PURPOSE:To surely prevent torque from abruptly rising, by making magnetic fluxes diffrent from each other, which pass through plural concentric annular pieces of an armature that are obtained by dividing the latter, to provide differences in time for magnetic absorption. CONSTITUTION:In an electromagnetic coupling device, a magnetic material outer ring member 18, a nonmagnetic material ring member 19 and an annular groove 21 which is formed in an output pulley 4 consisting of a magnetic material annular member 20 formed with a boss section 20A and in which the ring member 19 and a nonmagnetic material member 22 are embedded, constitute magnetic shield sections B, C which have different magnetic shield cross-sectional areas from each other. Therefore, concentric annular pieces of the armature which confront the magnetic shield section B having a larger magnetic shield cross- sectional area are absorbed to the output pulley 4 earlier than concentric annular pieces of the armature which confront the magnetic shield section C, thereby the rise of torque may be made moderate. |
