System for controlling a hydraulic variable-displacement pump

Abstract

In the case of a system for controlling a hydraulic variable displacement pump, the latter is acted upon in the direction of increasingly pump capacity over an energy storage system and, in the opposite direction, over a hydraulic adjusting device, the adjustment of the variable displacement pump being controlled over a flow regulator, which is constructed especially as a restrictor and the passable cross section of which is variable and which is located in the connection between the adjusting device and the reservoir, and which, for the sudden increase in the pump capacity of the variable displacement pump, opens up a drainage cross section to the reservoir, over which cross section an almost loss-free drainage of the pressure medium, displaced by the admission over the energy storage system, is possible.

1 . System for controlling a hydraulic variable-displacement in which a variable displacement pump is acted upon in its control direction, corresponding to the increase in the pump capacity, over an energy storage system, and, in the opposite direction, over a hydraulic control device, which is controlled at a return pipeline that is branched off from the a high pressure intake, discharges excess amounts pumped and runs out into a reservoir, and furthermore, is controlled as a function of the return pipeline pressure between a flow-control valve in the return pipeline and a flow regulator downstream therefrom, a connection to the reservoir, variable in the discharging cross section, being assigned to the control device, the flow regulator forming the connection of variable discharging cross section to the reservoir and that the control device is located in the return pipeline between the flow-control valve and the flow regulator, the discharging cross section of the control device, controlled over the flow regulator, being controlled in such a manner with respect to the reservoir that, when the variable displacement pump is adjusted to the maximum pump capacity, the size of the drainage cross section is maximized for an unrestricted drainage.  
   
   
       2 . The system of  claim 1 , wherein the flow regulator is controlled as a function of control parameters specified by the consumer.  
   
   
       3 . The system of  claim 1 , wherein the flow regulator is controlled as a function of parameters determined by the consumer environment.  
   
   
       4 . The system of  claim 1 , wherein the flow regulator is an adjustable restrictor.  
   
   
       5 . The system of  claim 1 , wherein a measurement restrictor is disposed downstream, in the direction of the control device, from the flow-control valve controlling the passable cross section of the hydraulic control device and that a control piston, which is constructed as a pressure-maintaining valve, is acted upon by pressure, on the one hand, through the connection to the pressure side of the variable displacement pump and, in the opposite direction to this, by a spring as well as over a branch, which is connected downstream from the measurement restrictor.  
   
   
       6 . The system of  claim 1 , wherein the control device is adjusted, the volumes of the control device, which change in opposite directions (pressure space, rear area) are connected with one another and communicate with little loss.  
   
   
       7 . The system of  claim 1 , wherein the system is a control agent of a power-assisted steering system.  
   
   
       8 . The system of  claim 1 , wherein the system is for a transmission.  
   
   
       9 . The system of  claim 1 , wherein the variable displacement pump is as a rotary vane pump.  
   
   
       10 . The system of  claim 1 , wherein the system is for a continuous variable automatic transmission (CVT).