The pump comprises a rotor (4) which is made from three parts (16-18), of which two are produced as identical castings or sintered parts (16,17). The two parts are joined to the rotating third part, which is made as a casting or sintered component, by welding. The spacing gap between the two identical parts forms the slot (6) for the slider (7). The connecting section (18) forms a bearing shaft (19) for the floatingly mounted rotor.
