Pump device

A pump device, comprising:

• a pump housing having a pump space therein;
• a pump piston longitudinally movable in the pump housing, the pump piston being connected to and actuated by an actuating solenoid;
• an outlet valve in the pump housing being openable by the pump piston for discharging a fluid during a delivery stroke;
• in the pump space of the pump housing, during a suction stroke, the pump piston being capable of generating a negative pressure and, upon passing over a control edge of the pump housing delimiting the pump space, the pump piston being capable of establishing a fluid connection between a fluid inlet in the pump housing and the pump space allowing the pump space under an effect of the negative pressure present in the pump space and filling the pump space with a filling volume of the fluid resulting from a fluid flow routed along an outer circumference of parts of the pump piston in a direction of the outlet valve, and subsequently, during the delivery stroke, the filling volume being discharged from the pump space via the outlet valve;
• and
• the pump space having various chambers provided with different diameters, the various chambers including a central chamber having at least partially a diameter that is forming an annular gap between the pump housing and an outer wall of the pump piston with an outer diameter of the pump piston in an area of a guide of the pump piston in the pump housing.