Driving motor, especially for a pump

Described is a drive motor, in particular for a pump, which has a rotor having a drive shaft, and a stator enclosed by a stator casing which is enclosed by an outer casing. The stator casing and the outer casing form an intermediate space which is hermetically sealingly closed off and which is filled with a cooling fluid. The cooling fluid is positively moved by means of a coolant impeller. For that purpose the coolant impeller is coupled to the drive shaft of the electric drive motor by means of a permanent magnet coupling which is in the form of a synchronous coupling, a hysteresis coupling or an eddy current coupling.