Piston Pump With Improved Efficiency

Abstract

The present invention relates to a piston pump for delivering hydraulic fluid, including a reciprocating piston for building up pressure in a pressure chamber; a sealing element is situated on the piston; during a compression phase, this sealing element produces a seal between the pressure chamber and a low-pressure region of the piston pump and during an intake phase, it opens a connection between the pressure chamber and the low-pressure region in order to draw hydraulic fluid into the pressure chamber.

1 - 18 . (canceled) 
   
   
       19 . A piston pump for delivering hydraulic fluid, the pump comprising a reciprocating piston for building up pressure in a pressure chamber; a sealing element on the piston this sealing element producing a seal between the pressure chamber and a low-pressure region of the piston pump during a compression cycle and opening a connection between the pressure chamber and the low-pressure region in order to draw hydraulic fluid into the pressure chamber during an intake phase. 
   
   
       20 . The piston pump according to  claim 19 , wherein the sealing element has an axial play on the piston. 
   
   
       21 . The piston pump according to  claim 19 , wherein the sealing element on the piston is situated in a stepped region of the piston. 
   
   
       22 . The piston pump according to  claim 19 , further comprising at least one raised region and at least one recessed region on an inner circumference of the sealing element in order to permit an overflow of the sealing element along the recessed region during the intake phase of the piston pump. 
   
   
       23 . The piston pump according to  claim 22 , wherein said at least one raised region and at least one recessed region comprise a plurality of plane-like raised regions that are separated from one another by means of an equal number of interposed plane-like recessed regions. 
   
   
       24 . The piston pump according to  claim 19 , further comprising a bevel on the inner circumference of the sealing element, at the edge oriented toward the low-pressure region. 
   
   
       25 . The piston pump according to  claim 22 , further comprising a bevel on the inner circumference of the sealing element, at the edge oriented toward the pressure chamber. 
   
   
       26 . The piston pump according to  claim 19 , further comprising a spring element exerting a spring force on the sealing element in the axial direction of the piston. 
   
   
       27 . The piston pump according to  claim 26 , wherein the spring element is a leaf spring with a number of protruding spring tabs. 
   
   
       28 . The piston pump according to  claim 26 , wherein the spring element is affixed to the piston. 
   
   
       29 . The piston pump according to  claim 27 , wherein the spring element is affixed to the piston. 
   
   
       30 . The piston pump according to  claim 26 , further comprising a plate-shaped retaining element fastened to the piston and supporting the spring element. 
   
   
       31 . The piston pump according to  claim 27 , further comprising a plate-shaped retaining element fastened to the piston and supporting the spring element. 
   
   
       32 . The piston pump according to  claim 19 , further comprising at least one flattened region on the circumference of the piston providing a flow path for hydraulic fluid from the low-pressure region to the sealing element. 
   
   
       33 . The piston pump according to  claim 19 , further comprising a cylinder element having a cylindrical region, the sealing element resting against the inside of the cylindrical region. 
   
   
       34 . The piston pump according to  claim 19 , further comprising at least one integrally embodied region on the piston, and a return spring for the piston engaging the at least one integrally embodied region. 
   
   
       35 . The piston pump according to  claim 34 , wherein the at least one integrally embodied region for supporting the return spring for the piston comprises a circumferential groove, and wherein the return spring is embodied in the form of a tapering spiral spring. 
   
   
       36 . The piston pump according to  claim 19 , further comprising a return spring for returning the piston to its initial position, the return spring being located in a cam chamber. 
   
   
       37 . The piston pump according to  claim 36 , wherein the return spring is a leaf spring, which is affixed in a groove in the piston. 
   
   
       38 . A brake system or stability system for a vehicle, including a piston pump according to  claim 19 .