Abstract: An electromagnetic clutch includes a first rotation transmission portion, annular field core, rotation stop member, second rotation transmission portion, armature, and spring member. The annular field core is supported by the first rotation transmission portion via a first bearing. The first bearing is housed in a hollow portion of the field core and fitted on an inner circumferential surface of the field core. The rotation stop member includes a flat portion which is fixed to an end of the field core on a side opposite to the armature. The flat portion is formed integrally with a retaining piece which projects toward the hollow portion of the field core and faces the first bearing when viewed from the axial direction of the field core.

Abstract: An electromagnetic clutch includes a first rotation transmission portion, annular field core, rotation stop member, second rotation transmission portion, armature, and spring member. The annular field core is supported by the first rotation transmission portion via a first bearing. The first bearing is housed in a hollow portion of the field core and fitted on an inner circumferential surface of the field core. The rotation stop member includes a flat portion which is fixed to an end of the field core on a side opposite to the armature. The flat portion is formed integrally with a retaining piece which projects toward the hollow portion of the field core and faces the first bearing when viewed from the axial direction of the field core.

Abstract: An electromagnetic coupling device includes a damper rubber member to mitigate the sound generated during attraction of the armature to the rotor. The spring constant of the damper rubber member is increased by increasing the contact surface of the damper rubber member at a head portion of the torque transmission pin.