Hydraulic control system
First Claim
Patent Images
1. A hydraulic control system comprising:
- a variable displacement hydraulic pump for pumping a working fluid;
a hydraulic actuator;
a line connecting said hydraulic actuator to said hydraulic pump such that said hydraulic actuator receives the working fluid from said hydraulic pump;
a control valve provided in said line for changing a flow rate of the working fluid;
a control element which controls said control valve according to a manipulated variable; and
discharge control means for controlling a working fluid discharge quantity of said hydraulic pump such that;
a) the discharge quantity increases for increases of the manipulated variable beyond a threshold level of the manipulated variable, andb) a ratio of increase of the discharge quantity to increase of the manipulated variable adjacent the threshold level is smaller for larger discharge pressures in said line at a position between said pump and said control valve and is larger for smaller discharge pressures in said line at said position between said pump and said control valve.
2 Assignments
0 Petitions
Accused Products
Abstract
A control valve is provided in a line between a variable displacement hydraulic pump and a hydraulic cylinder. The control valve controls flow rate of working fluid supplied to the hydraulic cylinder according to a manipulated variable of a lever. The control increases a discharge of the hydraulic pump in association with the increase in the manipulated variable and also controls to suppress the discharge as the discharge pressure of the hydraulic pump increases. A proper response corresponding to the operator'"'"'s feeling can be realized in consideration of an actual pressure loaded on an actuator on the basis of a positive control system.
-
Citations
8 Claims
-
1. A hydraulic control system comprising:
-
a variable displacement hydraulic pump for pumping a working fluid; a hydraulic actuator; a line connecting said hydraulic actuator to said hydraulic pump such that said hydraulic actuator receives the working fluid from said hydraulic pump; a control valve provided in said line for changing a flow rate of the working fluid; a control element which controls said control valve according to a manipulated variable; and discharge control means for controlling a working fluid discharge quantity of said hydraulic pump such that; a) the discharge quantity increases for increases of the manipulated variable beyond a threshold level of the manipulated variable, and b) a ratio of increase of the discharge quantity to increase of the manipulated variable adjacent the threshold level is smaller for larger discharge pressures in said line at a position between said pump and said control valve and is larger for smaller discharge pressures in said line at said position between said pump and said control valve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
Specification