Abstract:
An apparatus for controlling an electrohydraulic system of a work machine having an engine that drives a variable displacement pump is disclosed. A pump displacement setting device produces a pump command signal indicative of a desired displacement of the variable displacement pump. An engine speed setting device produces an engine command signal indicative of a desired rotational speed of the engine. A power manager receives the pump and engine command signals, determines an efficient engine speed and pump displacement, and produces an engine control signal that decreases the engine speed to the efficient engine speed and a pump control signal that increases the pump displacement to an efficient pump displacement, while maintaining a substantially constant pump flow rate.
Abstract:
A control device for variable hydraulic machines, and specifically for variable axial piston machines equipped with a servo system that is connected to a swash plate so that the discharge/displacement volume is infinitely variable. The hydraulic machine is equipped with a sensor that detects the piston displacement and is connected with an electronical control unit that controls the swash angle position of the swash plate and is pressure controlling the servo system by an electrohydraulic converter. A method for the infinite controlling of the volume flow of hydraulic machines, by which the servo system is connected to the swash plate of the hydraulic machine, and by which a conduction of a signal from a sensor to the control unit, a pressure controlling of the servo system by an electrohydraulic converter as well as the controlling of the swash angle position of the swash plate by the electronical control unit is realized.
Abstract:
The invention concerns an output and moment regulation device for an adjustable hydraulic pump (1) with a hydraulic servo setter for the continuous adjustment of the delivery rate. Adjustment of the delivery rate is dependent on the delivery pressure of the hydraulic pump (1) in a delivery pressure line (10) and an actuating pressure in a control line (12), and the setter is provided with a spring (4) which forces a pump regulating member (3) in the direction of maximum delivery rate and with at least one piston (6) which acts on the pump regulating member (3) in the direction of delivery rate reduction. The piston face can be subjected via a hydraulically operated control valve (8) to the feed pressure, or is connected to a discharge (19), the control valve (8) is actuated by actuating pressure in the control line (12), and a moment valve (17) is provided whose closure force is set by a metering spring arrangement (18) connected to the pump regulating member (3) and pre-stressed in accordance with the delivery pressure setting; and the moment valve (17) connects the control line (12) to the discharge (19) in accordance with the control pressure in the control line (12) and the pre-stress in the metering spring arrangement (18); and the control line (12) which branches off from the operating pressure line (15) of the pump is provided with an adjustable choke device (13) for adjusting the control pressure acting on the control valve (8) and moment valve (17), specifically, on the closure members thereof.
Abstract:
A standard hydraulic control valve block has a first control valve (2) and a second control valve (3) that co-operates with the first control valve and communicates therewith through hydraulic medium lines (28-31, 33). The second control valve (3) has a valve piston (5) controlled on the one hand by a hydraulic control pressure in a pressure chamber (25) and on the other hand by a spring pressure part (7). In order to simplify the construction and mounting of the control valve block without affecting its operation and using a remote controlled seat valve, an additional hydraulic medium line (36) is designed in the control valve block and the spring pressure part (7) of the second control valve (3) is replaced by an electrically controlled seat valve (60.1; 60.2). The seat valve (60.1; 60.2) has an electromechanical control part (66.1; 66.2) and at least two hydraulic connections (63.1; 64.1) that act as a valve inlet (63) and a valve outlet (64.1; 64.2). The valve piston (5) of the second control valve (3) is at rest so that one (64.1; 64.2) of both hydraulic connections (63, 64.1; 64.2) of the seat valve (60.1; 60.2) is at the same time connected to an available hydraulic connection (T) and the other hydraulic connection (63) is connected to the additional hydraulic medium line (36).
Abstract:
The invention concerns an output and moment regulation device for an adjustable hydraulic pump (1) with a hydraulic servo setter for the continuous adjustment of the delivery rate. Adjustment of the delivery rate is dependent on the delivery pressure of the hydraulic pump (1) in a delivery pressure line (10) and an actuating pressure in a control line (12), and the setter is provided with a spring (4) which forces a pump regulating member (3) in the direction of maximum delivery rate and with at least one piston (6) which acts on the pump regulating member (3) in the direction of delivery rate reduction. The piston face can be subjected via a hydraulically operated control valve (8) to the feed pressure, or is connected to a discharge (19), the control valve (8) is actuated by actuating pressure in the control line (12), and a moment valve (17) is provided whose closure force is set by a metering spring arrangement (18) connected to the pump regulating member (3) and pre-stressed in accordance with the delivery pressure setting; and the moment valve (17) connects the control line (12) to the discharge (19) in accordance with the control pressure in the control line (12) and the pre-stress in the metering spring arrangement (18); and the control line (12) which branches off from the operating pressure line (15) of the pump is provided with an adjustable choke device (13) for adjusting the control pressure acting on the control valve (8) and moment valve (17), specifically, on the closure members thereof.
Abstract:
A capacitor controller of a variable capacity hydraulic pump comprising a capacity control cylinder (6) including a capacity control piston (6a) for driving a capacity control member (5) of a variable capacity hydraulic pump, and a large diameter chamber (7) and a small diameter chamber (10) disposed on both sides of the capacity control piston (6a), for driving the capacity control piston (6a) in a capacity decreasing direction by a pressure oil supplied to the large diameter chamber (7) and driving the capacity control piston (6a) in a capacity increasing direction by the pressure oil supplied to the small diameter chamber (10), a passage allowing the small diameter chamber (10) to communicate with a pump exhaust path (2), at least one control valve (8, 9) for controlling the capacity of the variable capacity pump by selectively allowing the large diameter chamber (7) to communicate with the pump exhaust passage (2) or with a tank (56), and a variable throttle valve (30) disposed in a passage which allows the large diameter chamber (7) to communicate with the pump exhaust passage (2) or with the tank (56), and controlling the flow of the pressure oil supplied to, or flowing out from, the large diameter chamber (7), wherein the variable throttle valve (30) can be switched between a first state where the throttle open area is inversely proportional to the self exhaust pressure of the pump exhaust passage (2) and a second state where the throttle open area is set to a predetermined open area by an external signal irrespective of the self exhaust pressure.