Piston pump

Abstract

The invention relates to a piston pump having a pump housing including a plurality of pump components determining the function of the piston pump, such as a pump piston which is guided in sections, a piston return spring, and a suction and pressure valve. The piston pump also has an annular chamber which delimits the pump piston on the suction side and is designed as a compensating chamber for the liquid, a delivery chamber which delimits the pump piston on the pressure side, and an elastic sealing ring for sealing the pump piston in the direction of a pump drive chamber. To prevent leakage in the direction of the pump drive chamber, the elastic sealing ring is provided with a groove into which is inserted a spring element which presses the sealing ring against the pump piston.

1 . A piston pump, for delivering pressure medium in hydraulic brake systems with traction control, having a pump housing which a plurality of pump components which define the function of the piston pump, including a pump piston which is guided in sections in a guide band and is pressed into the pump housing and an annular space which limits the pump piston on the suction side and is configured as a replenishment space for the fluid, and having a delivery space which limits the pump piston on the pressure side, and having an elastic sealing ring which is arranged between the annular guide band and a stepped bore in the pump housing for sealing the pump piston in a leak-free manner in the direction of a piston drive space which is formed in the pump housing, wherein the elastic sealing ring is provided with a groove, in which a spring element which presses the sealing ring onto the pump piston is inserted. 
     
     
         2 . The piston pump as claimed in  claim 1 , wherein the elastic sealing ring is manufactured from a material with unrestricted dry running characteristics. 
     
     
         3 . The piston pump as claimed in  claim 1 , wherein the sealing ring is fixed in the pump housing directly between the guide band and a supporting ring which is pressed into the stepped bore, an annular gap being provided between the supporting ring and the sealing ring. 
     
     
         4 . The piston pump as claimed in  claim 3 , wherein an axial gap is arranged between the supporting ring and the pump piston, which axial gap extends to the annular gap, as a result of which a pressure medium connection is produced between the replenishment space and the sealing ring. 
     
     
         5 . The piston pump as claimed in  claim 1 , wherein the sealing ring is fixed directly between a bore step in the pump housing and the guide band in the pump housing, the guide band is pressed into the stepped bore, an annular gap being provided between the guide band and the sealing ring. 
     
     
         6 . The piston pump as claimed in  claim 5  wherein an axial gap is arranged between the guide band and the stepped bore, the axial gap extending to the annular gap, as a result of which a pressure medium connection is produced between the replenishment space and the sealing ring. 
     
     
         7 . The piston pump as claimed in  claim 1 , wherein, in order to generate a constant pressing force of the sealing ring onto the circumferential face of the pump piston, the spring element is configured as a spreading element which generates a radial force. 
     
     
         8 . The piston pump as claimed in  claim 1 , wherein the groove is configured as an annular groove which opens laterally into the sealing ring, runs around over the side face of the sealing ring, and the groove opening of which faces the annular gap. 
     
     
         9 . The piston pump as claimed in  claim 2 , wherein the material with unrestricted dry running characteristics is polytetrafluoroethylene (PTFE).