The pump consists of a flange body where a rotor (4) is enclosed having a slit (6) where a slider can move. The rotor consists of at least two pieces (13,14) of which at least one piece (13) is formed by sintering. The other piece is rotatable and is formed as a journal (14). The journal has a cylindrical recess (15) which is pressed by the cylindrical neck (16) of the sintered piece. A hollow space (17) which is left between the cylindrical recess and the cylindrical neck is filled with a metal (18) of low melting point. When the rotor is heat treated the low-melting point metal, melts and penetrates the porous zone (19) of the sintered piece.
