Rotational drive mechanism for driving impeller of water pump of motor vehicle, has electromagnetic device for generating magnetic field to modulate magnetic coupling between ring and track to vary rotation speed of impeller

摘要

The mechanism has a coupling system including an annular magnetic track (11) with an angular alternation of permanent North and South poles and a ring (12) made of a hysteresis magnetic material. The track is secured to an impeller (1) or a rotating element (2). The ring is placed at a distance from air-gap of the track for being magnetized to ensure rotational driving of the impeller by magnetic coupling between the ring and the track. The system has an electromagnetic device to generate a magnetic field to modulate the coupling to vary a rotation speed of the impeller.