Electromagnetically operated friction disk-free clutch

The electromagnetic disk-free clutch includes a cylindrical rotor supported on one rotary part and defining at one end face a frictional disk and at the other end face an annular groove which accommodates a tubular stator with an electromagnetic coil. The frictional ring of the rotor faces a corresponding frictional ring of a spring-biased armature which is supported for joint rotation and for an axial displacement on the other rotary part. The stator part adjoining the open end of the annular gap is radially extended to form a covering flange having a cross section substantially equal to the cross section of the axially directed parts of the stator and the rotor. The face of the rotor forming the frictional ring is provided with uniformly distributed openings and the axial dimension of the annular groove in the rotor exceeds that of the stator. The resulting air gap between the bottom of the annular groove and the stator prevents the formation of attractive forces acting on the stator in axial direction and the openings in the end portion of the rotor cause a compression of the magnetic flux before it enters the armature.