Abstract: An electromagnetic clutch assembly for use with a refrigerant compressor for an automotive air-conditioning system includes a first rotatable member, such as a rotor, having an axial end plate of magnetic material and a second rotatable member connected to an outer end of a drive shaft of the compressor. An armature plate of magnetic material is elastically connected to the second rotatable member. The armature plate faces the axial end plate of the rotor with an axial air gap therebetween. An electromagnetic device is disposed within the rotor and is operable to attract the armature plate into contact with the axial end surface of the rotor such that the rotation of the rotor can be transmitted to the drive shaft when the electromagnetic device is activated.

Abstract: In an electromagnetic clutch comprising a plurality of leaf springs for supporting an armature plate (18) to a shaft (14) so that the armature plate (18) faces a pulley (16) in an axial direction with a gap left therebetween, each of the leaf springs has a substantial length which is adjusted in response to a size of the gap. This results in changing of a spring constant of each of the leaf springs. When the armature plate is moved towards the pulley, the size of the gap becomes gradually small. Simultaneously, the armature plate is subjected to a suction force which acceleratingly increases in response to decreasing of the size of the gap. However, it is possible to reduce a noise which is generated when the armature plate is attracted to the pulley. This is because the armature plate comes into soft collision with the pulley.