The disclosure relates to an internal gear pump as a hydraulic pump for a slip-controlled vehicle brake system. The disclosure proposes to configure the internal gear pump as a preassembled module with a cartridge as housing, which can be pressed into a receptacle of a hydraulic block of the vehicle brake system. The cartridge has two steps which are parallel to one another for attaching a press-in ram and for orienting the cartridge in an angularly correct manner by means of the press-in ram, and a sealing surface, with which the cartridge bears in a sealed manner in the receptacle of the hydraulic block when the cartridge is pressed into the receptacle.