Screw pump

The invention relates to a screw pump, comprising a spindle housing in which a drive spindle and at least one driven spindle meshing therewith are accommodated, the drive spindle having a spindle core and at least two spindle contours surrounding the spindle core, on the end side of which a coupling element is arranged in a recess axially delimited by a bottom surface, the two contour recesses between the two spindle contours are offset by 180 degrees and communicate with the recess, and wherein the coupling element has a socket for a drive shaft of the drive motor and is rotationally fixedly coupled to the drive spindle in at least one rotational direction of the drive spindle by means of a form-fitting engagement with an axially projecting projection, the projection laterally defines a recess and engages in a lateral receptacle of the coupling element, the bottom surface is defined by the main shaft core in the outlet region of the two contour recesses, and the coupling element is rounded in the element reg