Hydraulic system for a vehicle, such as an aircraft

Abstract

A hydraulic system for reducing mechanical loads or noise development is disclosed having at least two hydraulic pumps including a pump element, such as a piston or rotary gear. The hydraulic pumps can be speed-controlled by a pump controller to achieve a nominal pressure P0. The pump controller further includes an offset (Δx) between the pump elements and controls one of the hydraulic pumps such that the pump elements move in an anti-cyclic manner, that is, a phase shift of about 180°.

1 . A hydraulic system for a vehicle, comprising:
 a plurality of hydraulic pump apparatus configured for generating hydraulic pressure, each hydraulic pump apparatus comprising a hydraulic pump, wherein the hydraulic pump has a pump discharge and at least one pump element that is configured to displace hydraulic fluid through the pump discharge to generate the hydraulic pressure, wherein the pump discharges are fluidly connected to form a common discharge; and   a pump controller configured to determine an offset between a pair of pump elements, wherein the pump controller is configured to adjust the offset such that the pair of pump elements moves in an anti-cyclic manner.   
     
     
         2 . The hydraulic system according to  claim 1 , wherein the pump controller is configured to adjust the offset such that one of the pair of pump elements discharges hydraulic fluid, when the other of the pair of pump elements draws in hydraulic fluid. 
     
     
         3 . The hydraulic system according to  claim 1 , wherein at least one pump discharge and/or the common discharge comprises a pressure sensor that is configured for measuring the pressure of the hydraulic fluid, and the pump controller is configured to control each hydraulic pump apparatus by controlling a speed of the hydraulic pump, such that a nominal pressure is kept at the respective pump discharge and/or common discharge. 
     
     
         4 . The hydraulic system according to  claim 1 , wherein the hydraulic pump apparatus comprises an electric pump motor that is operatively coupled to the pump controller to be controlled and that drives the hydraulic pump. 
     
     
         5 . The hydraulic system according to  claim 1 , further comprising a position determining unit that is configured to determine a pump element position of each pump element, and the pump controller is configured to determine the offset based on the pump element positions of the pair of pump elements. 
     
     
         6 . The hydraulic system according to  claim 5 , wherein the position determining unit comprises a position sensor that is configured to measure a quantity that is indicative of the pump element position. 
     
     
         7 . The hydraulic system according to  claim 6 , wherein the position sensor is chosen from a group consisting of an optical position sensor, a magnetic position sensor, a resolver, an electrical power sensor, and an electrical current sensor. 
     
     
         8 . The hydraulic system according to  claim 6 , wherein the position sensor is disposed on the hydraulic pump, the pump element, or the electric pump motor. 
     
     
         9 . The hydraulic system according to  claim 1 , wherein the pump controller is configured to adjust the offset by controlling the speed of the hydraulic pump. 
     
     
         10 . The hydraulic system according to  claim 1 , further comprising at least one hydraulic actuator that is supplied with hydraulic fluid from the common discharge. 
     
     
         11 . An aircraft comprising a hydraulic system according to  claim 1 , wherein the hydraulic system is configured to drive any of a high-lift device, a door or freight door, a landing gear, and a control surface. 
     
     
         12 . A method for operating a hydraulic system according to  claim 1 , the method comprising:
 a plurality of hydraulic pump apparatus generating hydraulic pressure, each hydraulic pump apparatus comprising a hydraulic pump, wherein the hydraulic pump has least one pump element that displaces hydraulic fluid through a pump discharge to generate the hydraulic pressure, and the pump discharges are combined into a common discharge; and   a pump controller determining an offset between a pair of pump elements, wherein the pump controller adjusts the offset such that the pair of pump elements moves in an anticyclic manner.   
     
     
         13 . The method according to  claim 12 , further comprising:
 a position determining unit determining a pump element position of each pump element, and the pump controller determining the offset based on the pump element positions of the pair of pump elements.   
     
     
         14 . The method according to  claim 13 , wherein the pump controller adjusts the offset by controlling the speed of the hydraulic pump. 
     
     
         15 . The method according to  claim 12 , further comprising at least one hydraulic actuator being supplied with hydraulic fluid from the common discharge.