Patent ID: 6324841
Filing Date: 2001-12-04
Classification: F04B

Abstract:
Output- and/or torque-regulating device for at least two adjustable hydraulic pumps (10, 11) having in each case one hydraulic servo control unit (22, 23) per hydraulic pump (10, 11) for infinitely variable adjustment of the delivery rate,wherein the delivery rate of each hydraulic pump (10, 11) is determined by the pressure of the respective hydraulic pump (10,11) in a delivery pressure line (16, 17) associated with the hydraulic pump (10, 11) and by the pressures in control lines (20,21) provided for each hydraulic pump (10, 11),wherein each servo control unit (22, 23) comprises a swing-out device (31, 32) setting a pump actuator (37, 38) for maximum delivery rate and a piston (39, 40), which acts upon the pump actuator (37, 38) to reduce delivery rate and the piston area of which is loaded by the delivery pressure or connected to an outlet (41) by means of a hydraulically operated control valve (25, 28), and operation of the control valve (25, 28) is effected by the control pressure in the control line (20; 21) of the, in each case, associated hydraulic pump (10;11),wherein for each servo control unit (22, 23) there is provided a torque valve (42, 43) having a valve piston (62), which is moved in a valve sleeve (61) and forms a sealing fit with the valve sleeve (61) and the closing force which is determined by a measuring spring arrangement (4, 47), the measuring spring arrangement (4, 47) connected to the pump actuator (37, 38) and preloaded depending upon the set delivery rate,and wherein each torque valve (42; 43) connects the control line (20; 21) of the, in each case, associated hydraulic pump (10; 11) depending upon the pressure in said control line (20;21) and upon the control pressure in the control line (21; 20) or the control pressures in the control lines of the, in each case, other hydraulic pump(s) (11; 10) to the outlet (41) with simultaneous preloading of the measuring spring arrangement (46; 47),characterized inthat for a specific hydraulic pump (10; 11) the control pressure in the control line (21; 20) or the control pressures in the control lines of the, in each case, other hydraulic pump(s) (11; 10) act(s) both upon the valve piston (62) and upon the valve sleeve (61) of the torque valve (42; 43) associated with the specific hydraulic pump (10; 11) andthat the output- and/or torque-regulating device controls two adjustable hydraulic pumps (10,11) and in the torque valve (22; 23) of a specific hydraulic pump (10,11) the control line (21; 20) of the, in each case, other hydraulic pump (11; 10) loads a valve sleeve-positioning piston (83) with the control pressure prevailing in said control line (21; 20), with the result that the valve sleeve-positioning piston (83) displaces the valve sleeve (61) inside the valve housing (60) against a restoring spring (81) and/or the measuring spring arrangement (46; 47).