Pump Element of a Hydraulic Unit for a Vehicle Brake System

Abstract

A pump element of a hydraulic unit for a vehicle brake system is configured to deliver brake fluid via a piston that is mounted so as to reciprocate in a cylinder. The piston has a first and a second active surface, of which the first active surface is configured to cause brake fluid to be delivered from the cylinder during forward movement of the piston, and the second active surface is configured to cause brake fluid to be delivered from the cylinder during backward movement of the piston.

1 . A pump element of a hydraulic unit for a vehicle brake system, configured to deliver brake fluid via a piston mounted so as to reciprocate in a cylinder,
 wherein the piston has a first and a second active surface, of which the first active surface is configured to cause brake fluid to be discharged from the cylinder during forward movement of the piston and the second active surface is configured to cause brake fluid to be discharged from the cylinder during backward movement of the piston.   
     
     
         2 . The pump element as claimed in  claim 1 , wherein the first and second active surfaces are configured to be of different sizes in relation to each other. 
     
     
         3 . The pump element as claimed in  claim 1 , wherein
 the first active surface is located so as to act in a first cylinder chamber and the second active surface is located so as to act in a second cylinder chamber; and   the pump element includes a first line, through which brake fluid can flow from the first cylinder chamber into the second cylinder chamber during the forward movement of the piston.   
     
     
         4 . The pump element as claimed in  claim 3 , wherein a first non-return valve is positioned in the first line. 
     
     
         5 . The pump element as claimed in  claim 3 , wherein the first line passes through the piston. 
     
     
         6 . The pump element as claimed in  claim 1 , wherein the pump element includes only one suction line that is configured to feed brake fluid to the piston. 
     
     
         7 . The pump element as claimed in  claim 3 , wherein:
 the pump element includes only one pressure line that is configured to discharge brake fluid via the piston; and   the one pressure line is connected to the second cylinder chamber.   
     
     
         8 . The pump element as claimed in  claim 1 , wherein the pump element includes an intake chamber into which brake fluid is drawn during the forward movement of the piston. 
     
     
         9 . The pump element as claimed in  claim 8 , wherein the pump element further includes a second line, through which brake fluid is transferred from the intake chamber to the first active surface during the backward movement of the piston. 
     
     
         10 . The pump element as claimed in  claim 9 , wherein the second line passes through the piston.