Coolant pump with plastic bonded magnet

A combustion engine coolant pump for pumping a coolant to an internal combustion engine, the combustion engine coolant pump comprising:

• a stationary pump frame;
• a driving wheel configured to be driven by the internal combustion engine;
• a pump wheel configured to be driven by the driving wheel;
• a switchable friction clutch configured to couple the driving wheel with the pump wheel, the switchable friction clutch comprising,
• a friction surface arranged at the driving wheel,
• only one separate ferromagnetic body, and
• a shiftable clutch disc comprising a ferromagnetic material, the shiftable clutch disk corresponding to the friction surface, and being,
• connected with the pump wheel,
• configured to co-rotate with the pump wheel, and
• axially shiftable between an engaged position and a disengaged position;
• an axial pretension spring configured to pretension the shiftable clutch disc into the disengaged position with a pretension force;
• a permanent magnet comprising a plastic bonded permanent magnet body comprising permanent magnetic particles embedded into a first plastic matrix material, the permanent magnet being configured to have a permanent magnet polarization and to cause an axial magnetic attraction force which forces the shiftable clutch disc towards the friction surface into the engaged position;
• and
• an electromagnet arranged in a magnetic circuit together with the permanent magnet, the electromagnet being configured, when energized, to generate an electromagnet polarization which is opposite to the permanent magnet polarization of the permanent magnet so as to reduce a total magnetic attraction force of the permanent magnet with respect to the shiftable clutch disc to thereby push the shiftable clutch disc into the disengaged position via the pretension spring,
• wherein,
• the only one separate ferromagnetic body of the switchable friction clutch is configured to directly support each of the permanent magnet and the electromagnet.