Control device for a hydraulic piston machine with a variable flow rate

Abstract

A control device for a hydraulic piston machine with a variable flow rate averaged over time has a plurality of pistons each defining a working chamber with a changeable value and connectable to high-pressure and low-pressure line via first and second valves actuable in an electric fashion, and an electronic control unit operating the valves in several modes, so that the valves can be operatable only in the partial stroke mode, or in the partial stroke mode and in the idle stroke mode, or in the partial stroke mode and in the full stroke mode, or in the way that all three modes are used on a limited number of working chambers and only the idle stroke and the full stroke modes are used on the remaining working chambers.

1 . A control device for a hydraulic piston machine, having a variable flow rate averaged over time, having a plurality of pistons ( 12 ) that each define a working chamber ( 13 ) whose volume changes with the stroke of a piston ( 12 ) and that is connectable to a high-pressure line ( 16 ) via a first valve ( 17 ,  45 ) and to a low-pressure line ( 18 ) via a second valve ( 19 ,  35 ), with at least one of the two valves of a working chamber being actively actuatable in an electric fashion, and having an electronic control unit ( 25 ) that is able to operate the actively actuatable valves ( 19 ,  35 ,  45 ) of the working chambers ( 13 ) in a partial stroke mode in which only a portion of the piston stroke is used,
 wherein the actively actuatable valves ( 19 ,  35 ,  45 ) are operable only in the partial stroke mode.   
     
     
         2 . A control device for a hydraulic piston machine, having a variable flow rate averaged over time, having a plurality of pistons ( 12 ) that each define a working chamber ( 13 ) whose volume changes with the stroke of a piston ( 12 ) and that is connectable to a high-pressure line ( 16 ) via a first valve ( 17 ,  45 ) and to a low-pressure line ( 18 ) via a second valve ( 19 ,  35 ), with at least one of the two valves of a working chamber being actively actuatable in an electric fashion, and having an electronic control unit ( 25 ) that is able to operate the actively actuatable valves ( 19 ,  35 ,  45 ) of the working chambers ( 13 ) in an idle stroke mode in which the piston stroke is not used and a partial stroke mode in which only a portion of the piston stroke is used,
 wherein the actively actuatable valves ( 19 ,  35 ,  45 ) are operable only in the partial stroke mode and in the idle stroke mode.   
     
     
         3 . A control device for a hydraulic piston machine, having a variable flow rate averaged over time, having a plurality of pistons ( 12 ) that each define a working chamber ( 13 ) whose volume changes with the stroke of a piston ( 12 ) and that is connectable to a high-pressure line ( 16 ) via a first valve ( 17 ,  45 ) and to a low-pressure line ( 18 ) via a second valve ( 19 ,  35 ), with at least one of the two valves of a working chamber being actively actuatable in an electric fashion, and having an electronic control unit ( 25 ) that is able to operate the actively actuatable valves ( 19 ,  35 ,  45 ) of the working chambers ( 13 ) in a partial stroke mode in which only a portion of the piston stroke is used and a full stroke mode in which the full piston stroke is used,
 wherein the actively actuatable valves ( 19 ,  35 ,  45 ) are operable only in the partial stroke mode and in the full stroke mode.   
     
     
         4 . A control device for a hydraulic piston machine, having a variable flow rate averaged over time, having a plurality of pistons ( 12 ) that each define a working chamber ( 13 ) whose volume changes with the stroke of a piston ( 12 ) and that is connectable to a high-pressure line ( 16 ) via a first valve ( 17 ,  45 ) and to a low-pressure line ( 18 ) via a second valve ( 19 ,  35 ), with at least one of the two valves of a working chamber being actively actuatable in an electric fashion, and having an electronic control unit ( 25 ) that is able to operate the actively actuatable valves ( 19 ,  35 ,  45 ) of the working chambers ( 13 ) in an idle stroke mode in which the piston stroke is not used, a partial stroke mode in which only a portion of the piston stroke is used, and a full stroke mode in which the full piston stroke is used,
 wherein all three modes are used on only a limited number of working chambers ( 13 ) and only the idle stroke mode and the full stroke mode are used on the remaining working chambers.   
     
     
         5 . The control device as recited in  claim 4 ,
 wherein all three modes are used only on every other working chamber ( 13 ).   
     
     
         6 . The control device as recited in  claim 4 , wherein all three modes are always used on the same working chambers ( 13 ). 
     
     
         7 . The control device as recited in  claim 1 ,
 wherein the electronic control unit ( 25 ) makes a new respective selection of the mode in successive cycles of the piston machine and in the partial stroke mode, makes a new respective selection of the useful stroke of a piston ( 12 ).   
     
     
         8 . The control device as recited in  claim 1 ,
 wherein once the mode has been selected for a working chamber ( 13 ), it is maintained over the course of at least two successive cycles of the piston machine.   
     
     
         9 . The control device as recited in  claim 8 ,
 wherein during an operation of a working chamber ( 13 ) in the partial stroke mode, the height of the useful stroke is maintained over the course of at least two successive cycles of the piston machine.