Patent ID: 7825558

Claim:
A fan having an electronically commutated drive motor for driving fan blades, which drive motor comprises a stator; a rotor equipped with a shaft, which shaft is radially journaled in non-contact fashion on the stator using permanent magnets and is axially displaceable relative to the stator and is drivingly connected to the rotor, which rotor is in turn drivingly connected to a fan wheel whose interior defines a cylindrical air gap in which, during operation, a substantially radial magnetic flux extends in a predetermined direction, a plunger coil which extends into the cylindrical air gap and to which the stator is mechanically connected, so that, upon an axial displacement of the shaft relative to the stator, a relative location, of the plunger coil with respect to the cylindrical air gap, changes, and an axially-magnetized permanent magnet which generates a magnetic flux in the cylindrical air gap, said permanent magnet having, associated with it, a flux-conducting piece that has an approximately cylindrically configured external periphery which defines a radially inner boundary of the cylindrical air gap.