Reciprocating-Piston Pump With Plain Bearing Traversed By Flow

An electromagnetically driven reciprocating-piston pump, comprising:

• a cylinder having a cylinder bearing surface;
• a piston having a piston bearing surface and configured to displace a liquid, the piston received in the cylinder to form a bearing gap between the cylinder bearing surface and the piston bearing surface;
• at least one depression defined in at least one of the cylindrical bearing surface and the piston bearing surface, where the at least one depression extends along a length of the piston or the cylinder in the form of a spiral shaped groove;
• a valve located at an end of the piston;
• and
• an armature chamber spaced apart from the valve and positioned relative to the piston, wherein a low-resistance fluidic connection is formed through the valve, into a transverse bore, and connected to the armature chamber at least partially by a flow of the liquid delivered by the piston acting in interaction with the cylinder by way of the at least one depression to provide an output rate of the reciprocating-piston pump.