Piston Pumps for a Hydraulic Vehicle Brake System

Abstract

A piston pump as a recirculating pump of a hydraulic traction control vehicle brake system is disclosed, with two pump pistons which are arranged in an opposed arrangement and bear on the outside against an eccentric bearing ring for their lifting drive. The pump pistons are arranged with an offset in the longitudinal direction of a pump shaft, so that they exert a moment upon the bearing ring, which moment presses rolling bodies in the rolling bearing against the pump shaft even when the forces with which the pump pistons press from outside against the bearing ring cancel one another. The rolling bodies roll even when the forces of the pump pistons are compensated.

1 . A piston pump for a hydraulic vehicle brake system, the piston pump having a rotationally drivable pump shaft, a rolling bearing, arranged on the pump shaft, with a bearing ring, and at least two pump pistons which are arranged around the rolling bearing and the end faces of which bear against the bearing ring, and further the pump pistons have an offset in the longitudinal direction of the pump shaft. 
     
     
         2 . The piston pump according to  claim 1 , wherein the offset is smaller than a diameter of the pump pistons. 
     
     
         3 . The piston pump according to  claim 1 , wherein the rolling bearing has a rolling bearing cage. 
     
     
         4 . The piston pump according to  claim 1 , wherein each pump piston has a piston return spring which acts upon it against the bearing ring. 
     
     
         5 . The piston pump according to  claim 1 , wherein the pump pistons are arranged opposite one another with respect to the pump shaft. 
     
     
         6 . The piston pump according to  claim 1 , wherein the rolling bearing has bodies of revolution as rolling bodies. 
     
     
         7 . The piston pump according to  claim 1 , wherein:
 the bearing ring is arranged eccentrically with respect to the pump shaft, and   the rolling bodies have different diameters correspondingly to a different gap width between the pump shaft and the bearing ring.