Kolbenpumpe

摘要

A piston pump delivering hydraulic liquid, especially for vehicle braking systems, with a step piston which can be displaced axially in a pump compartment (11) .In order to lower production costs of the step piston (12) said piston is made from one cylinder (14) with a substantially constant outer diameter and a fixed sleeve (16) which cannot be displaced axially and which is preferably pressed onto the cylinder (16). An elastomer seal is placed on a section of the cylinder (141) limited by the sleeve (16), thereby sealing the cylinder (14) in relation to the wall (111) of the pump compartment (11) and subdividing it into two pumping chambers (21,22) with variable volumes.