Drive system having at least one hydraulic actuator

Abstract

The invention relates to a drive system having at least one hydraulic actuator ( 2 ), which is supplied with pressure medium ( 4 ) by means of at least one pressure-medium pump ( 3 ) in a main circuit, the pressure-medium pump ( 3 ) being a rotational-speed-controlled pressure-medium pump that is driven by a motor ( 5 ) at a variable rotational speed and a controlled torque, said drive system being characterized in that leakage fluid ( 7 ) that escapes from a displacement chamber ( 6 ) of the pressure-medium pump ( 3 ) is discharged through a fluid-conducting connection ( 8 ) having at least one check valve ( 9, 16 ), and the at least one check valve ( 9, 16 ) is installed in the fluid-conducting connection ( 8 ) in such a way that the check valve prevents pressure medium from flowing back out of the main circuit into the displacement chamber ( 6 ) or another interior chamber of the pressure-medium pump ( 3 ) and feeds leakage fluid ( 7 ) into the main circuit of the drive system ( 1 ) when there is a slight excess pressure.

1 . A drive system having at least one hydraulic actuator ( 2 ), which is supplied with a pressure medium ( 4 ) by means of at least one pressure medium pump ( 3 ) in a main circuit, wherein the pressure medium pump ( 3 ) is a speed-controlled pressure medium pump, which is driven by a motor ( 5 ) at a variable speed and a controlled torque, characterized in that the leakage fluid ( 7 ), escaping from a displacement chamber ( 6 ) of the pressure medium pump ( 3 ), is discharged through a fluid-conducting connection ( 8 ) having at least one check valve ( 9 ,  16 ), and that the at least one check valve ( 9 ,  16 ) is installed in the fluid-conducting connection ( 8 ) in such a way that the check valve prevents the pressure medium from flowing back out of the main circuit into the displacement chamber ( 6 ) or another interior chamber of the pressure medium pump ( 3 ) and feeds the leakage fluid ( 7 ) into the main circuit of the drive system ( 1 ) when there is a slight excess pressure. 
     
     
         2 . The drive system according to  claim 1 , characterized in that the pressure medium pump ( 3 ) has at least one low pressure port ( 14 ,  14 ′) and/or at least one high pressure port ( 15 ,  15 ′). 
     
     
         3 . The drive system according to  claim 2 , characterized in that the leakage fluid ( 7 ) is discharged at least at one low pressure port ( 14 ,  14 ′) of the pressure medium pump ( 3 ). 
     
     
         4 . The drive system according to  claim 2 , characterized in that the fluid-conducting connection ( 8 ) runs through the respective low pressure port ( 14 ,  14 ′) to at least one high pressure port ( 15 ,  15 ′); and that each port ( 2 ) of the connection ( 8 ) has a check valve ( 9 ,  16 ). 
     
     
         5 . The drive system according to  claim 1 , characterized in that the pressure medium pump ( 3 ) is an axial piston machine; and that two check valves ( 9 ,  16 ) that open in opposite directions are activated in the fluid-conducting connection ( 8 );
 and the fluid-conducting connection ( 8 ) is connected in parallel to a high pressure port ( 15 ,  15 ′) respectively of the axial piston machine.   
     
     
         6 . The drive system according to  claim 1 , characterized in that the pressure medium pump ( 3 ) is bi-directional in the two-quadrant operating mode or is speed-controlled in the four-quadrant operating mode. 
     
     
         7 . The drive system according to  claim 1 , characterized in that the pressure medium pump ( 3 ) charges a pressure accumulator ( 10 ) with a pressure medium ( 4 ); and this pressure accumulator also charges the hydraulic actuator ( 2 ) with pressure medium ( 4 ). 
     
     
         8 . The drive system according to  claim 1 , characterized in that the hydraulic actuator ( 2 ) is an actuating device ( 11 ) for a hydraulic system for roll stabilization of a vehicle. 
     
     
         9 . The drive system according to  claim 7 , characterized in that the pressure accumulator ( 10 ) prestresses the pressure medium ( 4 ) on the intake side ( 12 ) of the pressure medium pump ( 3 ). 
     
     
         10 . The drive system according to  claim 7 , characterized in that the pressure accumulator ( 10 ) charges the pressure medium ( 4 ) in a working chamber ( 13 ,  13 ′) of the hydraulic actuator ( 2 ). 
     
     
         11 . The drive system according to  claim 7 , characterized in that the hydraulic actuator ( 2 ) and the pressure medium container are actuated by a directional control valve in such a way that a suction process is realized. 
     
     
         12 . The drive system according to  claim 1 , characterized in that the pressure medium pump ( 3 ) is used for supplying pressure medium to two hydrostatic working cylinders ( 17 ) that work in opposite directions. 
     
     
         13 . The drive system according to  claim 12 , characterized in that the working cylinders ( 17 ) that work in opposite directions are connected in each instance to a valve ( 18 ) for draining the pressure medium ( 4 ) out of each one of their working chambers ( 13 ,  13 ′). 
     
     
         14 . The drive system according to  claim 13 , characterized in that a check valve (R) is arranged parallel to the valve ( 18 ) in a pressure medium line bridging the valve ( 18 ); and that at least one check valve (R) enables the pressure medium ( 4 ) to flow out of the pressure medium container to the respective hydraulic actuator ( 2 ).