Patent ID: 8342078

Claim:
Reciprocating-piston pump having an electromagnetically driveable reciprocating piston having an end surface, which is mounted with a restoring spring, for feeding a liquid, an impact damper composed of an elastomer for damping an impact of the reciprocating piston at the end of a feed phase, a core flange having a core flange surface which is situated opposite the reciprocating piston, with an optimized and substantially uniform gap dimension across the reciprocating piston end surface and core flange surface, which is dependent on the position of the reciprocating piston being provided between the reciprocating piston and the core flange, wherein the kinetic energy of the reciprocating piston during an early feed interval of a feed phase is absorbed primarily by the restoring spring and the feed of the liquid, wherein the kinetic energy of the reciprocating piston during a late feed interval of a feed phase is absorbed primarily by the hydraulic damping of the liquid present in the gap, and wherein the gap width between the reciprocating piston and core flange in the radial direction perpendicular to the axial movement direction of the reciprocating piston at the end of the feed phase is between 1.0 and 0.1 mm.