Pump unit for a high-pressure pump

A pump unit for a high-pressure pump, comprising:

• a pump housing having a low-pressure inlet via which a working medium is fed to a working chamber formed in the pump housing, and a high-pressure outlet via which the working medium is discharged from the working chamber,
• a pump piston channel formed in the pump housing, the pump piston channel having a longitudinal axis,
• a pump piston having a solid form with no internal passages or hollows and arranged movably along the longitudinal axis in the pump piston channel and coupled hydraulically directly to the working chamber,
• a compensation piston coupled hydraulically directly to the working chamber and arranged movably in a compensation piston channel having a second axis,
• wherein the compensation piston channel is arranged along the longitudinal axis opposite the pump piston channel, and
• a spring element coupled mechanically to the compensation piston at an end of the compensation piston that faces away from the working chamber, the spring element disposed in a compensation vessel, wherein the spring element is configured to influence a position of the compensation piston based on a force which acts on the spring element,
• wherein the compensation piston moves against the spring element to keep the pressure in the working chamber constant over the course of a continuation of the delivery stroke of the pump piston, and the compensation piston hydraulically separates the compensation vessel from the working chamber,
• wherein the working medium enters the compensation vessel via the low-pressure inlet.