Power-assisted steering pump

Abstract

The invention relates to a pump, especially a power-assisted steering pump, comprising a current regulating valve, the current regulating valve comprising a hydraulic resistance, such as a main throttle and a regulating piston, whereby the main throttle can optionally be a regulating pin and an annular orifice.

1 - 11 . (canceled).  
     
     
         12 : A pump comprising: 
 a flow-control valve having a hydraulic resistance; and    an electrically adjustable bypass throttle valve disposed in parallel to the flow control valve.    
     
     
         13 : The pump as recited in  claim 12 , wherein the pump is for a vehicle power-assisted steering system.  
     
     
         14 : The pump as recited in  claim 12 , wherein the flow-control valve includes a control piston and a primary throttle valve.  
     
     
         15 : The pump as recited in  claim 14 , wherein the primary throttle valve includes a control pin and an annular orifice.  
     
     
         16 : The pump as recited in  claim 12 , wherein a volumetric flow rate from the pump to a consumer is electrically changeable.  
     
     
         17 : The pump as recited in  claim 16 , wherein the consumer is a vehicle steering system.  
     
     
         18 : The pump as recited in  claim 14 , wherein a pressure differential acting on the bypass throttle valve is the same as a pressure differential acting on the primary throttle valve.  
     
     
         19 : The pump as recited in  claim 16 , wherein the bypass throttle valve reduces the volumetric flow rate from the pump to the consumer in response to an increasing drive current.  
     
     
         20 : The pump as recited in  claim 16 , wherein the bypass throttle valve increases the volumetric flow rate from the pump to the consumer in response to an increasing drive current.  
     
     
         21 : The pump as recited in  claim 14 , wherein the electrically adjustable bypass throttle valve is installed onto an existing pump having the flow control valve.  
     
     
         22 : The pump as recited in  claim 14 , wherein the primary throttle valve provides a basic volumetric flow rate to a steering system with or without electrical power, and wherein the electrically adjustable bypass throttle valve is configured to modify the basic volumetric flow rate to a modified volumetric flow rate according to at least one parameter.  
     
     
         23 : The pump as recited in  claim 22 , wherein the at least one parameter includes at least one of a driving speed, an engine speed, a cornering behavior, a braking characteristic, a vehicle stability, a steering angle, a steering-wheel angular velocity, a wheel speeds and a wheel slip.  
     
     
         24 : The pump as recited in  claim 12 , wherein the electrical bypass throttle valve saves energy.  
     
     
         25 : The pump as recited in  claim 12 , wherein the electrical active bypass throttle valve enables an active steering system.