Valve arrangement for pressure medium supply of a hydraulic consumer

Abstract

A valve arrangement for supplying pressure medium to a hydraulic consumer has two utility ports (A, B) for fluid connection to the consumer and has a first control valve. The first control valve (20) has a first intake (24) via which a first intake flow from the first utility port (A) to the consumer (10) is controllable, has a first return control orifice (26) via which a first return flow (28) from the consumer (10) via the second utility port (B) is controllable simultaneously with the first intake (24), has a second intake (34) via which a second intake flow from the second utility port (B) to the consumer (10) is controllable, and having a second return control orifice (36), via which a second return flow (38) from the consumer (10) via the first utility port (A) is controllable simultaneously with the second intake (34). A second control valve (40) has an intake control orifice (42) used to control the respective intake (24, 34) of the first control valve (20).

Claims

1. A valve arrangement for supplying a fluid pressure medium to a hydraulic consumer, the valve arrangement comprising: first and second utility ports connected in fluid communication to the hydraulic consumer; a pressure supply port; a first control valve having a first inlet controlling a first inlet flow from the first utility port to the hydraulic consumer, having a first control orifice controlling a first return flow from the hydraulic consumer to the second utility port simultaneously with the first inlet, having a second inlet controlling a second inlet flow from the second utility port to the hydraulic consumer, and having a second return control orifice controlling a second return flow from the hydraulic consumer to the first utility port simultaneously with the second inlet; a second control valve with an intake control orifice controlling the respective inlet of the first control valve; a third control valve in a fluid communication connection between the pressure supply port and the second control valve, the third control valve being a 2/2-way pressure compensator controlling a supply of pressure between the pressure supply port and the second control valve, a supply control orifice of the third control valve supply pressure medium in a first position of the third control valve and blocking supply of pressure medium in a second position of the third control valve, the third control valve having a control port receiving a control pressure from a fluid communication connecting line between the second and third control valves to a blocking side of the third control valve; and a load sensing pressure control line being connected to the third control valve on a supply side of the third control valve opposite the blocking side and applying load sensing pressure to the supply side, the load sensing pressure control line being connected to a fluid communication connection line between the first and second control valves.

2. A valve arrangement according to claim 1 wherein the fluid communication connection of the third control valve between the pressure supply port and the second control valve is pressure balanced.

3. A valve arrangement according to claim 1 wherein at least one of the first inlet or the second inlet of the first control valve is without a flow constricting cross section.

4. A valve arrangement according to claim 1 wherein the first inlet and the second inlet of the first control valve are without flow constricting cross sections.

5. A valve arrangement according to claim 4 wherein only the first, second and third control valves control fluid flow between the pressure supply port and the first and second utility ports.

6. A valve arrangement according to claim 1 wherein the first control valve is at least one of a ¾-way proportional valve or a 4/4-way proportional valve being actuatable by pilot pressure regulators.

7. A valve arrangement according to claim 1 wherein the first control valve is a 4/4-way proportional valve being actuatable by pilot pressure regulators and having a floating position for the hydraulic accumulator.

8. A valve arrangement according to claim 1 wherein the second control valve is a 2/2-way proportional valve operable by a pilot pressure regulator, the intake control orifice being open for fluid flow through the second control valve in an activated state of the second control valve and blocks return flow from the first and second inlets of the first control valve in an unactivated state of the second control valve.

9. A valve arrangement according to claim 1 wherein a measurement device taps current fluid pressures at the first and second utility ports and transmits signals representative of the current fluid pressures to a control unit that initiates actuation of the first and second control valves and that control fluid pressure-supplied by a swivel-angle pump connected in fluid communication to the pressure supply port.

10. A valve arrangement according to claim 1 wherein the first control valve is connected on an input side thereof to the second control valve and comprises a return port on the input side of the first control valve.

11. A valve arrangement according to claim 10 wherein the return port is connected in fluid communication to a tank port connectable to a tank.

12. A valve arrangement according to claim 1 wherein the hydraulic consumer comprises a hydraulic working cylinder having a rod chamber and a piston chamber separated by a piston-rod unit.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Referring to the drawing that forms a part of this disclosure that is schematic and not to scale.

(2) The FIGURE is a hydraulic circuit diagram of the essential components of the valve arrangement according to an exemplary embodiment of the invention, with its single control valves and with an electronic control option (ECU).

DETAILED DESCRIPTION OF THE INVENTION

(3) The valve arrangement shown in the FIGURE is used to supply pressure media to a hydraulic consumer 10, in this case in the form of a hydraulic working cylinder. The cylinder has piston rod unit 12 that divides the cylinder into two working chambers, a piston chamber 14 and a rod chamber 16. The piston chamber 14 is connected to a utility port A, and the rod chamber 16 is connected to a utility port B of the hydraulic valve arrangement. Instead of a hydraulic working cylinder a different consumer may be used, for example in the shape of a hydro-motor (not shown). One pressure transducer 18 each is integrated in the fluid connection between the utility port A and the piston chamber 14 as well as between the utility port B and the rod chamber 16. Each pressure transducer 18 transmits its measured results to a central control unit or computing unit ECU (Electronic Control Unit) for further processing.

(4) The valve arrangement has a first control valve 20, which in one of its or first valve positions 22 controls a first intake flow from the first utility port A to the consumer 10 via a first intake 24. In this valve position 22, a first return control orifice 26 is used to route a first return flow 28 from the consumer 10 towards the tank T via the second utility port B at the same time as the first intake 24.

(5) In the FIGURE, the first control valve 20 is shown in its blocked neutral position 30. The appropriate operation of the first control valve 20 can bring it into a third valve position 32, in the viewing direction of the FIGURE, the left switching position. In this third valve position 32, the first control valve 20 has a second intake 34, via which a second intake flow from the second utility port B to the consumer 10 is controllable. A second return control orifice 36 is present, via which a second return flow 38 from the consumer 10 via the first utility port A to the tank T is controllable simultaneously with the second intake 34.

(6) The first and second intakes 24, 34 of the first control valve 20 are each free of means to narrow the flow cross section, in particular free of orifices or throttles.

(7) The valve arrangement has a second control valve 40 having an intake control orifice 42, which can be used to control the respective intake 24, 34 of the first control valve 20.

(8) The first control valve 20 is an electromagnetically actuatable 4/4-way proportional valve. In a fourth valve position 44 (shown on the far right), the first control device 20 permits a floating position for the connected consumer 10, i.e. for compensation of a pendulum volume. The piston chamber 14 is directly connected to the rod chamber 16 in the fourth valve position, wherein additional control fluid can be fed from the second control valve 40. At that, a return port 46, connected to the first control valve 20 on the input side, having a connecting line 47 to the tank T, is blocked. As the aforementioned floating position or the valve position 44 is not absolutely necessary, the valve arrangement according to the invention can also be implemented omitting this function and using an electromagnetically actuatable ¾-way proportional valve.

(9) The first control valve 20 is, as usual and in the illustrated manner, held in its neutral position 30 in the non-energized state by two opposing compression springs. Proportional solenoids act in directions of action parallel to the respective compression spring at the valve on opposite control sides. Each proportional solenoid can be actuated, i.e. energized, by the central control unit ECU. While the output side of the first control valve 20 is connected to the two utility ports A, B in a fluid-conveying manner, another connecting line 48, which leads to the output of the second control valve 40, is provided on the input side in addition to the connecting line 47 leading to the first control valve 20.

(10) The second control valve 40 in turn is formed from an electromagnetically actuatable 2/2-way proportional valve. In its actuated position, the intake control orifice 42 is activated. In its un-actuated position, shown in the FIGURE, however, a possible return flow originating from the first intake 24 and the second intake 34 of the first control valve 20, is prevented, namely by a check valve 49 integrated in the second control valve 40. Check valve 49 prevents in its closed position the corresponding return from the output of the second control valve 40 in the direction of its fluid input. Preferably, the non-return valve 49 shuts off the corresponding return medium in a leak-proof manner. Also, in turn, the second control valve 40, in its de-energized state, is held in its shown blocked position by a compression spring. Only upon appropriate current supply, triggered by the central control unit ECU, the proportional solenoid, arranged opposite from the compression spring, is used to open- or closed-loop control the intake flow via the intake control orifice 42 from the input side of the second control valve 40 to its output. Instead of the proportional solenoids, the first or the second control valve 20 or 40, particularly preferred barometric pilot controls having pilot-pressure regulators can be used, in particular for relatively large dimensioned fluid cross sections.

(11) The valve arrangement also has a third control valve 50, preferably in the shape of a pressure compensating valve, which is integrated into a connection between a pressure supply P and the second control valve 40. The third control valve 50 is preferably formed as a 2/2-way pressure compensating valve. In its neutral position shown, its intake control orifice 52 is used to control the intake flow between a pressure supply P and the second control valve 40. In the other position of this pressure compensating valve 50, the corresponding intake flow is blocked.

(12) A load sensing pressure LS acts on the third control valve control side, facing the intake control orifice 52. The load sensing pressure LS is taken from the connecting line 48 between the first control valve 20 and the second control valve 40. A control pressure is present at its control side, facing the blocking position. The control pressure is taken from a connecting line 54 between the second 40 and the third control valve 50. Thus, the output of the third control valve 50 is permanently connected in a fluid-conveying manner to the input side of the second control valve 40 via the line 54. At the side where the load-sensing pressure LS acts on the control side of the third valve 50, the corresponding action is co-supported by a compression spring at the third control valve 50. The load-sensing pressure LS, originating from the connecting line 48, can be transferred, if required, to further valve segments (not shown) via a connection point 56. Furthermore, the load-sensing pressure LS is available at an interface 58 of the valve unit 60, including the first, second and third control valves 20, 40 and 50. Such a load-sensing pressure LS can be used, for instance, to control a swivel-angle pump 62, serving for pressure supply P. The swivel-angle pump 62 in the present case, however, is solely electrically controlled by the central control unit ECU.

(13) The control unit or computer unit ECU shown can, as shown by arrows, receive operating commands on the input side and control some more further valve segments, not shown, on the output side.

(14) The valve arrangement according to the invention is used to implement a resolution of control edges via a first control valve 20 and a second control valve 40. The first control valve 20 has the respective return control orifices 26 and 36 for controlling the return flow from the consumer 10. The second control valve 40 has the intake control orifice 42 for actuating the intake flow to the first control valve 20 and thus to the consumer 10. A third control valve 50 inside the valve unit 60, which is interchangeable as a whole and is also available as a retrofit kit, is formed in the manner of a pressure compensating valve and in all permits an intake volume flow control for the consumer 10.

(15) While one embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the claims.