EP1135613B1 - Method and control device for controlling a hydraulic consumer - Google Patents

Method and control device for controlling a hydraulic consumer Download PDF

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Publication number
EP1135613B1
EP1135613B1 EP99963215A EP99963215A EP1135613B1 EP 1135613 B1 EP1135613 B1 EP 1135613B1 EP 99963215 A EP99963215 A EP 99963215A EP 99963215 A EP99963215 A EP 99963215A EP 1135613 B1 EP1135613 B1 EP 1135613B1
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EP
European Patent Office
Prior art keywords
pressure
control
pump
spring
consumer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP99963215A
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German (de)
French (fr)
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EP1135613A1 (en
Inventor
Burkhard KNÖLL
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bosch Rexroth AG
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Bosch Rexroth AG
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Publication of EP1135613A1 publication Critical patent/EP1135613A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/0416—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor with means or adapted for load sensing
    • F15B13/0417—Load sensing elements; Internal fluid connections therefor; Anti-saturation or pressure-compensation valves
    • F15B13/0418—Load sensing elements sliding within a hollow main valve spool
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F15B2211/30515—Load holding valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F15B2211/3053—In combination with a pressure compensating valve
    • F15B2211/30555—Inlet and outlet of the pressure compensating valve being connected to the directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/57—Control of a differential pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means

Definitions

  • the invention relates to a method for control a consumer according to the preamble of the claim 1 and a control arrangement for controlling a hydraulic consumer according to the preamble of the claim Second
  • Such a control arrangement is, for example, from WO 95/32364 A1 known.
  • a variable displacement pump is regulated in such a way that it Output creates a pressure that is around a certain Differential amount above the highest load pressure of all hydraulic Consumer of the tax arrangement lies. Let it go constant pumps in connection with a 3-way flow control valve or variable displacement pumps with changeable Use stroke volume.
  • a load sensing controller is provided, which in Meaning of a reduction in the volume of the variable displacement pump of pump pressure and in the sense of increasing the stroke volume the pump of the highest load pressure and one Compression spring can be acted upon.
  • the difference between that Pump pressure and the highest load pressure corresponds to the Force of this compression spring.
  • downstream pressure compensators are in which the pump adjusts to the maximum pressure volume has been and the pressure medium flow is not sufficient to the specified pressure drop across the orifice plates of all Consumers maintain the pressure balances of all controlled hydraulic consumers in the closing direction adjusted so that all pressure medium flows to the individual consumers reduced by the same percentage become.
  • LUDV systems load-independent flow distribution
  • the flow channels are used for reporting the highest load pressure for pump control and the Pressure springs of the individual pressure compensators designed in such a way that the load pressure is reported to the pump controller in an unadulterated manner becomes.
  • the hydraulic pump delivers one Stand-by pressure, which is, for example, 20 bar and to control some consumers or valve arrangements is needed.
  • the one corresponding to the stand-by print Pressure difference must be assigned to the other consumers Orifices are broken down, so that considerable Energy losses occur.
  • the invention is based on the object a method and a control arrangement for control to create at least one hydraulic consumer, where the energy losses are reduced to a minimum are.
  • the invention is reduced Load pressure to the pump reported.
  • the stroke volume of the pump depending on this reported (reduced) Load pressure set, so that the pressure loss accordingly above the orifice plate is less than the pressure difference on the pump controller (variable pump). That is, the pressure drop over the orifice plate is compared to the conventional Solutions reduced, so that a corresponding energy saving he follows.
  • Control arrangement When used to carry out the procedure Control arrangement will reduce this for pump control reported load pressure by interpreting the reaches a control piston of the pressure compensating control spring. This is compared with the state of the Technology much higher spring stiffness or preload designed so that the spring force is about that Pressure corresponds to the one reported to the pump controller Load pressure compared to the actually applied load pressure should be reduced. That is, the control arrangement differs essentially compared to conventional solutions by the choice of the spring, so that already existing Control arrangements easily converted can be.
  • the effective spring force preferably set such that they approximately half of the pressure difference corresponding to Pump controller is present or the state of the art the orifice plate falls off.
  • the response behavior of the control arrangement is special well if the spring force of the spring over the entire Hub, d. H. from a position with fully closed Control piston up to the fully open position remains about constant. This is particularly easy by means of a suitable pressure medium flow guide, where the resulting from the pressure medium flow Flow forces both in the closing direction and act in the opening direction of the pressure compensator and designed in this way are that they become one with the control spring force Add constants independent of the control piston stroke.
  • Such a pressure medium flow guide is, for example from the subsequently published P 198 36 564.0 known, the disclosure of which is expressly referred to here is taken.
  • the pressure compensator is preferably with a nozzle bore, through which at complete controlled pressure compensator the load pressure in the load pressure channel is fed.
  • the pressure compensator is preferably with a nozzle bore, through which at complete controlled pressure compensator the load pressure in the load pressure channel is fed.
  • the pressure in the load pressure reporting line is preferred via another connection hole in the pressure compensator reported in the spring chamber of the control piston, whereby this connection bore a damping nozzle for damping of pressure fluctuations.
  • control arrangement can with a Variable pump and associated control unit or with one Constant pump with inlet pressure balance (3-way flow control valve) be executed.
  • FIG. 1 shows a circuit diagram of a valve disk 2 a valve block with two working ports A, B, one Tank connection T and a pump connection P.
  • a consumer for example a hydraulic motor 116 or a double-acting one Cylinder (not shown) connected.
  • Via the hydraulic Circuit can be one of the working connections Connect A, B to pump port P while the other working connection B, A with the tank connection T is connected.
  • the valve disc also has a control connection LS, over which the load pressure at the assigned Consumer can be tapped.
  • the pump is a variable displacement pump executed, the delivery rate depending on Load pressure of the consumer is regulated.
  • load-sensing circuits are adequate in the prior art known, so that a basic description is dispensed with can be.
  • Figure 1 Construction When controlling several consumers via circuits with that shown in Figure 1 Construction is the highest in terms of consumers applied load pressure to the pump and the delivery rate depending on this highest load pressure set.
  • valve disc 2 In the valve disc 2 is a continuously adjustable Directional control valve 4 with a control direction of the Consumer defining direction and a Speedometer forming orifice plate added.
  • the orifice formed by the directional control valve 4 (Speed section) is connected to a pressure compensator 5, whose control piston 40 in its control position the pressure drop across the orifice independent of the load pressure keeps constant.
  • the output connection of the pressure compensator 5 is hydraulic with the directional part of the directional valve 4 connected, depending on the control one of the Working ports A, B supplied with pressure medium and the another is connected to the tank connection T.
  • In the work lines to the work connections A, B are continuous adjustable, unlockable check valve arrangements 6, 8 switched, the reverse flow in its blocking position prevent from the consumer and in the unlocked Pass position a backflow from the corresponding Working connection A or B towards tank connection T. enable.
  • the directional control valve 4 is activated via Pilot valves 10, 12, through which the end faces of a Directional valve spool 28 of the directional valve 4 with one Control pressure can be applied to this from his to shift the neutral position shown.
  • the Directional valve slide 28 is by two compression springs 30, 32nd biased to its neutral position.
  • the control piston 40 the pressure compensator 5 is in the closing direction of the force a control spring 44 and the highest load pressure Consumer loads through a load pressure channel 22 is tapped by the consumer.
  • the pressure downstream of the directional valve 4 is via a Control line 38 to the one acting in the opening direction End face of the control piston 40 out.
  • the pilot valves 10, 12 are continuously adjustable executed so that a pressure of the order between the tank pressure and the pressure at the pump connection P can be applied to the end faces of the directional valve slide 28 is. This control pressure is also used to unlock the Check valve assemblies 6 and 8 used.
  • a pressure relief valve 45 provided, via which the load pressure in the load pressure channel 22nd is limited.
  • the pressure relief valve 45 is in Spring closing direction and opening direction acted upon by the highest load pressure of the consumers. at If the maximum pressure is exceeded, control oil becomes tank T dissipated.
  • the load pressure channel 22 is furthermore connected to the tank via a tank throttle 47.
  • Figure 2 shows a specifically designed valve disc 2, in which the circuit according to FIG. 1 is implemented.
  • valve disc 2 has the two working connections A, B and a pump connection P and the tank connection T, which is the valve disc packing of the valve block perpendicular to the plane of the drawing.
  • the highest load pressure is all over the Valve block controlled consumers to one with the Load pressure channel 22 connected control connection LS performed.
  • the valve disc 2 has mounting holes for the Directional control valve 4, the directional control valve 28 as Hollow slide is formed.
  • the only in Figure 2 Dashed piston 40 is inside the Directional valve slide 28 out.
  • Each of the check valve assemblies 6 has a pre-opening main cone 72 which cooperates with an impact piston 92, via which the Main cone 72 for unlocking from its valve seat can be lifted off.
  • the two pilot valves 10, 12 are in Cartridge design and in the lower in Figure 2 End face of the valve disc 2 screwed in. Both Pilot valves 10, 12 are, for example electrically operated pressure reducing valves, via which the Pressure at the pump connection P to a system pressure at axial outlet connection of the respective pilot valve 10, 12 is reducible. As can be seen from Figure 1, has each pilot valve 10, 12 next to that with the pump connection P connected input port another one with the Tank connection T connected radial connection.
  • DE 196 46 428 A1 discloses a valve arrangement for Actuation of a double-acting consumer at the hydraulic fluid delivered by a pump via a Directional control valve optionally one of two working connections Can be fed, each of which a check valve assembly assigned. Each check valve arrangement is about controlled a pilot valve assigned to this, the Output control pressure also on one end of the Directional valve spool is present. By energizing both Pilot valves can be found in the directional valve spool Clamp the zero position and the two Unlock check valve assemblies so that the Working connections with the check valve arrangements with a tank can be connected and thus a floating position is adjustable.
  • valve disc 2 for receiving the Directional valve slide 28, a valve bore 50 in which Annular spaces 52, 54, 56, 58 extending radially outward and 60 are formed.
  • annular space 52 is dashed over a in Figure 2 indicated load pressure signaling line 62 with the Load pressure channel 22 connected to the control connection LS is led.
  • the two annular spaces 54 and 56 are over Working channels 66, 68 to the working connections A and B guided.
  • the annular space 58 is on the one hand Pump line 70 connected to the pump port P and on the other hand via a connecting channel 74 to one Radial connection of the pilot valves 10, 12 out.
  • the Annulus 60 is also hydraulic with the pump connection P connected.
  • the directional valve slide 28 is 30.32 in via compression springs biased its basic position shown in Figure 3.
  • the two compression springs 30, 32 are on locking screws 90 supported, the valve bore 50 in the axial direction to lock.
  • the Directional valve slide 28 is designed as a hollow piston and has an axial bore 94, which is shown in the illustration Figure 3 from the left end portion of the directional valve spool 28 extends into the area of the ring channel 60.
  • this axial bore 94 opens a measuring aperture bore star 96, whose breakthroughs as radial bores are formed in the directional valve spool jacket.
  • the orifice hole star 96 arranged between the two annular spaces 58, 60.
  • a directional bore star 98 formed in the shown basic position between the two annular spaces 54, 56 is arranged.
  • the control piston 40 is inside the axial bore 94 slidably guided and via the control spring 44 with a Ring face 100 against a stop shoulder Axial bore 94 biased into its closed position.
  • On Control piston spring chamber 104 is via a connecting bore 106, a damping throttle 108 and an opening 109 connected in the directional valve slide 28 to the annular space 52, so that the load pressure the control piston 40 also in Closing direction applied.
  • Control piston 40 an axial blind hole 110 which in the right ( Figure 4) end face of the control piston 40 opens.
  • the jacket of the control piston 40 is in the mouth region penetrated radially crown-shaped by openings 112.
  • a compensation bore star 114 is at a distance from these trained in the position shown in the area of the annular space 54 is arranged.
  • control piston 40 In the area between the openings 112 and the Bore star 114 is the control piston 40 radial downgraded so that a 112 in the area of the openings first control edge 116 and in the area of Compensation bore star 110 a second control edge 118 is formed.
  • the radially stepped section 115 is in the Area of the first control edge 116 as an inclined surface trained while in the area of the second Control edge 118 is designed as a radial stage.
  • the directional valve slide 28 has two according to Figure 4 axially spaced annular grooves 120, 122 which in the Inner peripheral surface of the axial bore 94 are formed.
  • the two ring grooves 120, 122 are through one Center web 124 separated from each other, the one with the second Control edge 118 cooperates.
  • the one in the illustration 4 right circumferential edge of the first annular groove 120 interacts with the first control edge 116, so that at Axial displacement of the control piston 40 through cooperation the first control edge 116 and the first annular groove 120 a control cross section is opened while by interaction of the second control edge 118 and the Mittelsteg 124 a compensation control cross section is opened.
  • the closed both tax cross sections Regarding further details of this compensation flow guidance on the subsequently published application 198 36 564.0 directed.
  • the directional bore star 98 opens into the first Ring groove 120.
  • the connecting bore 106 designed as an angle bore, with a radial bore leg 126 of the connection bore 106 in the opening 109 of the directional control valve 28 opens.
  • the radial bore leg 126 is arranged so that the connection between the ring channel 52 and the spring chamber 104 over the entire Stroke of the control piston 40 is open. That is, the Control piston 40 is always in the closing direction by the Force of the control spring 44 and the load pressure in the load pressure channel 22 acted upon.
  • the axial bore 110 of the control piston 40 opens its left end portion in a nozzle bore 128, the in turn in a radial bore 130 of the control piston 40 transforms.
  • the opening cross section of the nozzle bore 128 is that when the opening is open Pressure relief valve 45 from the load pressure channel 22 to the tank T flowing control oil quantity reduced so that the responsiveness and efficiency of the hydraulic Control can be improved.
  • the control spring 44 is in the embodiment shown with a large preload or a high spring stiffness executed so that about half the stand-by pressure the variable pump must be applied to the Shift control piston 40 against the force of the control spring 44. That is, at a stand-by pressure of about 20 bar, which in the circuit shown for actuating the Pilot valves 10, 12 is required, the control spring 44th designed as a 10 bar spring.
  • the pressure medium flow along the control piston 44 is by suitable geometric Design of the control cross section described at the beginning and in the opposite direction effective control cross-section designed so that the resultant from the force of the control spring 44 and the flow forces acting on the control piston is a constant that is independent of the control piston stroke. With in other words, the control spring 44 and the flow forces are coordinated so that the result is a horizontal spring characteristic, where the spring force is independent of the stroke of the control piston 40 is.
  • the pressure medium passes through the open orifice hole star 96 in the axial bore 94, see above that the control piston 40 of the pressure compensator against the force of the Control spring 44 is acted upon in the opening direction.
  • the control piston 40 of the pressure compensator against the force of the Control spring 44 is acted upon in the opening direction.
  • the control piston 40 of the pressure compensator against the force of the Control spring 44 is acted upon in the opening direction.
  • the control piston 40 By the pressure build-up at the inlet of the pressure compensator 5 becomes the control piston 40 brought into its left end position in FIG. 3, so that the compensation cross section and the control cross section are fully controlled on.
  • the radial bore 130 is opened via the control edge 132, so that the pressure at the input of the pressure compensator 5 over the axial blind bore 110, the nozzle bore 128, the Radial bore 130 and the opening 109 in the load pressure reporting line 62 and thus into the load pressure channel 22 is reported.
  • load pressure corresponds to the force of the control spring 44 lower than that at the inlet
  • the Stand-by pressure of the variable pump is 20 bar.
  • the Load pressure at the inlet of the pressure compensator, d. H. in the working channel 66, for example, should be 200 bar.
  • a method and a control arrangement are disclosed to control at least one hydraulic consumer.
  • the control arrangement has a pump whose output adjustable depending on the load pressure of a consumer is. Its control takes place via a Proportional directional control valve, one Pressure compensator is assigned, via which the pressure drop over the orifice plate is kept constant regardless of the load pressure. According to the invention, when the pressure compensator is fully open a lower load pressure to the pump is reported, so that the pressure drop across the orifice plate is reduced.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The invention relates to a method and a control device for controlling at least one hydraulic consumer. The control device has a pump. The output of the pump can be adjusted in accordance with the load pressure of a consumer. Control occurs by means of a proportional directional control valve (4) that forms a measuring diaphragm. A pressure balance (5) is associated with the control valve and enables the decrease in pressure to remain constant irrespective of load pressure by means of the measuring diaphragm. According to the invention, a lower load pressure is applied to the pump when the pressure balance is opened fully, whereby the decrease in pressure is attenuated by the measuring diaphragm.

Description

Die Erfindung betrifft ein Verfahren zur Ansteuerung eines Verbrauchers gemäß dem Oberbegriff des Patentanspruchs 1 und eine Steueranordnung zur Ansteuerung eines hydraulischen Verbrauchers gemäß dem Oberbegriff des Patentanspruchs 2.The invention relates to a method for control a consumer according to the preamble of the claim 1 and a control arrangement for controlling a hydraulic consumer according to the preamble of the claim Second

Eine derartige Steueranordnung ist beispielsweise aus der WO 95/32364 A1 bekannt. Bei dieser bekannten Lösung wird eine Verstellpumpe derart geregelt, daß sie an ihrem Ausgang einen Druck erzeugt, der um einen bestimmten Differenzbetrag über dem höchsten Lastdruck aller hydraulischen Verbraucher der Steueranordnung liegt. Dabei lassen sich Konstantpumpen in Verbindung mit einem 3-Wege-Stromregelventil oder Verstellpumpen mit veränderbarem Hubvolumen einsetzen.Such a control arrangement is, for example, from WO 95/32364 A1 known. In this known solution a variable displacement pump is regulated in such a way that it Output creates a pressure that is around a certain Differential amount above the highest load pressure of all hydraulic Consumer of the tax arrangement lies. Let it go constant pumps in connection with a 3-way flow control valve or variable displacement pumps with changeable Use stroke volume.

Für derartige Load-Sensing-Regelungen ist bei Verstellpumpen ein Load-Sensing-Regler vorgesehen, der im Sinne einer Verringerung des Volumens der Verstellpumpe vom Pumpendruck und im Sinne einer Vergrößerung des Hubvolumens der Pumpe vom höchsten Lastdruck und von einer Druckfeder beaufschlagbar ist. Die Differenz zwischen dem Pumpendruck und dem höchsten Lastdruck entspricht der Kraft dieser Druckfeder. Bei diesen Load-Sensing-Schaltungen ist jedem Verbraucher eine veränderbare Meßblende und eine vor- oder nachgeschaltete Druckwaage zugeordnet, über die der Druckabfall über der Meßblende konstant gehalten wird, so daß die zu einem hydraulischen Verbraucher fließende Druckmittelmenge allein vom Öffnungsquerschnitt der Meßblende und nicht vom Lastdruck des Verbrauchers oder vom Pumpendruck abhängt. Bei den Meßblenden nachgeschalteten Druckwaagen werden in dem Fall, in dem die Pumpe bis zum maximalen Druckvolumen verstellt worden ist und der Druckmittelstrom nicht ausreicht, um den vorgegebenen Druckabfall über den Meßblenden sämtlicher Verbraucher aufrecht zu erhalten, die Druckwaagen aller angesteuerten hydraulischen Verbraucher in Schließrichtung verstellt, so daß alle Druckmittelströme zu den einzelnen Verbrauchern um den gleichen Prozentsatz verringert werden. Bei derartigen LUDV-Systemen (lastunabhängige Durchflußverteilung) bewegen sich dann alle angesteuerten Verbraucher mit einer prozentual um den gleichen Wert verringerten Geschwindigkeit.For such load-sensing regulations is the case with variable pumps a load sensing controller is provided, which in Meaning of a reduction in the volume of the variable displacement pump of pump pressure and in the sense of increasing the stroke volume the pump of the highest load pressure and one Compression spring can be acted upon. The difference between that Pump pressure and the highest load pressure corresponds to the Force of this compression spring. With these load-sensing circuits is a changeable orifice plate for every consumer and assigned an upstream or downstream pressure compensator, through which the pressure drop across the orifice plate is kept constant becomes so that the hydraulic consumer flow of pressure medium only from the opening cross-section the orifice plate and not the load pressure of the consumer or depends on the pump pressure. At the orifice plates downstream pressure compensators are in which the pump adjusts to the maximum pressure volume has been and the pressure medium flow is not sufficient to the specified pressure drop across the orifice plates of all Consumers maintain the pressure balances of all controlled hydraulic consumers in the closing direction adjusted so that all pressure medium flows to the individual consumers reduced by the same percentage become. With such LUDV systems (load-independent flow distribution) then move all targeted consumers with a percentage around the same value reduced speed.

Bei LUDV-Systemen werden die Strömungskanäle zum Melden des höchsten Lastdrucks zur Pumpenregelung und die Druckfedern der Individualdruckwaagen derart ausgelegt, daß der Lastdruck unverfälscht zum Pumpenregler gemeldet wird.In LUDV systems, the flow channels are used for reporting the highest load pressure for pump control and the Pressure springs of the individual pressure compensators designed in such a way that the load pressure is reported to the pump controller in an unadulterated manner becomes.

Bei einigen Anwendungen liefert die Hydropumpe einen Stand-By-Druck, der beispielsweise bei 20 bar liegt und zum Ansteuern einiger Verbraucher oder Ventilanordnungen benötigt wird. Die dem Stand-By-Druck entsprechende Druckdifferenz muß an den den sonstigen Verbrauchern zugeordneten Meßblenden abgebaut werden, so daß erhebliche Energieverluste auftreten.In some applications, the hydraulic pump delivers one Stand-by pressure, which is, for example, 20 bar and to control some consumers or valve arrangements is needed. The one corresponding to the stand-by print Pressure difference must be assigned to the other consumers Orifices are broken down, so that considerable Energy losses occur.

Dem gegenüber liegt der Erfindung die Aufgabe zugrunde, ein Verfahren und eine Steueranordnung zur Ansteuerung zumindest eines hydraulischen Verbrauchers zu schaffen, bei denen die Energieverluste auf ein Minimum reduziert sind.In contrast, the invention is based on the object a method and a control arrangement for control to create at least one hydraulic consumer, where the energy losses are reduced to a minimum are.

Diese Aufgabe wird hinsichtlich des Verfahrens durch die Merkmale des Patentanspruchs 1 und hinsichtlich der Steueranordnung durch die Merkmale des Patentanspruchs 2 gelöst.This task is accomplished with regard to the procedure the features of claim 1 and in terms of Control arrangement by the features of claim 2 solved.

Während bei den bekannten Load-Sensing-Systemen die Regelfeder der Druckwaage stets schwach ausgebildet wurde, um bei vollständig geöffneter Druckwaage den zur Hydropumpe gemeldeten Lastdruck nicht zu verfälschen, wird im Gegensatz dazu bei der Erfindung ein verringerter Lastdruck zur Pumpe gemeldet. Das Hubvolumen der Pumpe wird in Abhängigkeit von diesem gemeldeten (verringerten) Lastdruck eingestellt, so daß entsprechend der Druckverlust über der Meßblende geringer ist als die Druckdifferenz am Pumpenregler (Verstellpumpe). D. h., der Druckabfall über der Meßblende wird gegenüber den herkömmlichen Lösungen verringert, so daß auch eine entsprechende Energieeinsparung erfolgt.While in the known load sensing systems The spring of the pressure compensator is always weak was used in order to open the pressure compensator Not to falsify the hydraulic pump reported load pressure, in contrast, the invention is reduced Load pressure to the pump reported. The stroke volume of the pump depending on this reported (reduced) Load pressure set, so that the pressure loss accordingly above the orifice plate is less than the pressure difference on the pump controller (variable pump). That is, the pressure drop over the orifice plate is compared to the conventional Solutions reduced, so that a corresponding energy saving he follows.

Bei der zur Durchführung des Verfahrens eingesetzten Steueranordnung wird diese Reduzierung des zur Pumpenregelung gemeldeten Lastdruckes durch die Auslegung der auf einen Regelkolben der Druckwaage wirkenden Regelfeder erreicht. Diese wird mit einer im Vergleich zum Stand der Technik wesentlich höheren Federsteifigkeit oder Vorspannung ausgelegt, so daß die Federkraft etwa demjenigen Druck entspricht, um den der zum Pumpenregler gemeldete Lastdruck gegenüber dem tatsächlich anliegenden Lastdruck verringert sein soll. D. h., die Steueranordnung unterscheidet sich gegenüber herkömmlichen Lösungen im wesentlichen durch die Wahl der Feder, so daß auch bereits vorhandene Steueranordnungen auf einfache Weise umgerüstet werden können.When used to carry out the procedure Control arrangement will reduce this for pump control reported load pressure by interpreting the reaches a control piston of the pressure compensating control spring. This is compared with the state of the Technology much higher spring stiffness or preload designed so that the spring force is about that Pressure corresponds to the one reported to the pump controller Load pressure compared to the actually applied load pressure should be reduced. That is, the control arrangement differs essentially compared to conventional solutions by the choice of the spring, so that already existing Control arrangements easily converted can be.

Beim Einsatz einer Regelfeder mit erhöhter Federsteifigkeit oder erhöhter Vorspannung wird die wirksame Federkraft vorzugsweise derart eingestellt, daß sie etwa der Hälfte derjenigen Druckdifferenz entspricht, die am Pumpenregler anliegt oder die beim Stand der Technik über der Meßblende abfällt.When using a control spring with increased spring stiffness or increased preload, the effective spring force preferably set such that they approximately half of the pressure difference corresponding to Pump controller is present or the state of the art the orifice plate falls off.

Das Ansprechverhalten der Steueranordnung ist besonders gut, wenn die Federkraft der Feder über den gesamten Hub, d. h. von einer Stellung mit vollständig geschlossenem Regelkolben bis zur vollständig geöffneten Stellung etwa konstant bleibt. Dies läßt sich besonders einfach durch eine geeignete Druckmittelströmungsführung erreichen, bei der die aus der Druckmittelströmung resultierenden Strömungskräfte sowohl in Schließrichtung als auch in Öffnungsrichtung der Druckwaage wirken und derart ausgelegt sind, daß sie sich mit der Regelfederkraft zu einer vom Regelkolbenhub unabhängigen Konstanten addieren.The response behavior of the control arrangement is special well if the spring force of the spring over the entire Hub, d. H. from a position with fully closed Control piston up to the fully open position remains about constant. This is particularly easy by means of a suitable pressure medium flow guide, where the resulting from the pressure medium flow Flow forces both in the closing direction and act in the opening direction of the pressure compensator and designed in this way are that they become one with the control spring force Add constants independent of the control piston stroke.

Eine derartige Druckmittelströmungsführung ist beispielsweise aus der nachveröffentlichten P 198 36 564.0 bekannt, auf deren Offenbarung hier ausdrücklich Bezug genommen wird.Such a pressure medium flow guide is, for example from the subsequently published P 198 36 564.0 known, the disclosure of which is expressly referred to here is taken.

Für den Fall, daß der Lastdruck in der zur Pumpe geführten Lastdruckmeldeleitung über ein Druckbegrenzungsventil begrenzt ist, wird die Druckwaage vorzugsweise mit einer Düsenbohrung ausgeführt, über die bei vollständig aufgesteuerter Druckwaage der Lastdruck in den Lastdruckkanal eingespeist wird. Durch die Düsenbohrungen in den den einzelnen Verbrauchern zugeordneten Druckwaagen werden die Verlustströmungen bei mehreren vollständig aufgesteuerten Druckwaagen und bei geöffnetem Druckbegrenzungsventil verringert. Auch dieses Vorsehen einer Düsenbohrung steht im Widerspruch zu den bisher bei Load-Sensing-Systemen eingesetzten Konstruktionen, da dort - wie eingangs erwähnt- stets ein unverfälschter Lastdruck zur Pumpenregelung gemeldet wurde. Aus diesem Grund wurde der hydraulische Widerstand des Strömungskanals zum Pumpenregler möglichst gering gewählt, damit der Druckabfall und eine Verfälschung des Lastdruckes bei vollständig geöffneter Druckwaage möglichst gering ausfällt.In the event that the load pressure in the pump Load pressure reporting line via a pressure relief valve is limited, the pressure compensator is preferably with a nozzle bore, through which at complete controlled pressure compensator the load pressure in the load pressure channel is fed. Through the nozzle holes in the pressure scales assigned to the individual consumers the loss flows in several fully controlled Pressure balances and with the pressure relief valve open reduced. This also provides a nozzle bore is in contradiction to the previous load sensing systems used constructions because there - as mentioned at the beginning - always an unadulterated load pressure for pump control has been reported. For this reason the hydraulic resistance of the flow channel to the pump controller chosen as low as possible so that the pressure drop and a falsification of the load pressure when fully open Pressure balance is as low as possible.

Der Druck in der Lastdruckmeldeleitung wird vorzugsweise über eine weitere Verbindungsbohrung in der Druckwaage in den Federraum des Regelkolbens gemeldet, wobei diese Verbindungsbohrung eine Dämpfungsdüse zur Dämpfung von Druckschwankungen aufweist.The pressure in the load pressure reporting line is preferred via another connection hole in the pressure compensator reported in the spring chamber of the control piston, whereby this connection bore a damping nozzle for damping of pressure fluctuations.

Die erfindungsgemäße Steueranordnung kann mit einer Verstellpumpe und zugehöriger Regeleinheit oder mit einer Konstantpumpe mit Eingangsdruckwaage (3-Wege-Stromregelventil) ausgeführt sein.The control arrangement according to the invention can with a Variable pump and associated control unit or with one Constant pump with inlet pressure balance (3-way flow control valve) be executed.

Sonstige vorteilhafte Weiterbildungen der Erfindung sind Gegenstand der weiteren Unteransprüche.Other advantageous developments of the invention are the subject of further subclaims.

Im folgenden wird ein bevorzugtes Ausführungsbeispiel der Erfindung anhand schematischer Zeichnungen näher erläutert.The following is a preferred embodiment the invention with reference to schematic drawings.

Es zeigen:

  • Figur 1 ein Schaltschema einer erfindungsgemäßen Steueranordnung;
  • Figur 2 eine Ventilscheibe mit der Steueranordnung aus Figur 1;
  • Figur 3 eine Detaildarstellung einer Ventilanordnung mit einer verstellbaren Meßblende und einer nachgeschalteten Druckwaage und
  • Figur 4 eine Detaildarstellung der Ventilanordnung aus Figur 3.
    • Show it:
  • Figure 1 is a circuit diagram of a control arrangement according to the invention;
  • FIG. 2 shows a valve disk with the control arrangement from FIG. 1;
  • Figure 3 is a detailed view of a valve assembly with an adjustable orifice and a downstream pressure compensator and
  • FIG. 4 shows a detailed illustration of the valve arrangement from FIG. 3.

    • Figur 1 zeigt einen Schaltplan einer Ventilscheibe 2 eines Ventilblocks mit zwei Arbeitsanschlüssen A, B, einem Tankanschluß T und einem Pumpenanschluß P. An die beiden Arbeitsanschlüsse A, B ist ein Verbraucher, beispielsweise ein Hydromotor 116 oder ein doppeltwirkender Zylinder (nicht dargestellt) angeschlossen. Über die hydraulische Schaltung läßt sich einer der Arbeitsanschlüsse A, B mit den Pumpenanschluß P verbinden, während der jeweils andere Arbeitsanschluß B, A mit dem Tankanschluß T verbunden ist.FIG. 1 shows a circuit diagram of a valve disk 2 a valve block with two working ports A, B, one Tank connection T and a pump connection P. To the two working ports A, B is a consumer, for example a hydraulic motor 116 or a double-acting one Cylinder (not shown) connected. Via the hydraulic Circuit can be one of the working connections Connect A, B to pump port P while the other working connection B, A with the tank connection T is connected.

    Die Ventilscheibe hat des weiteren einen Steueranschluß LS, über den der Lastdruck an dem zugeordneten Verbraucher abgegriffen werden kann.The valve disc also has a control connection LS, over which the load pressure at the assigned Consumer can be tapped.

    Die nicht dargestellte Pumpe ist als Verstellpumpe ausgeführt, deren Förderleistung in Abhängigkeit vom Lastdruck der Verbraucher geregelt wird. Derartige Load-Sensing-Schaltungen sind im Stand der Technik hinlänglich gekannt, so daß auf eine grundlegende Beschreibung verzichtet werden kann. Bei der Ansteuerung mehrerer Verbraucher über Schaltungen mit dem in Figur 1 dargestellten Aufbau wird der jeweils höchste an den Verbrauchern anliegende Lastdruck zur Pumpe gemeldet und die Förderleistung in Abhängigkeit von diesem höchsten Lastdruck eingestellt.The pump, not shown, is a variable displacement pump executed, the delivery rate depending on Load pressure of the consumer is regulated. Such load-sensing circuits are adequate in the prior art known, so that a basic description is dispensed with can be. When controlling several consumers via circuits with that shown in Figure 1 Construction is the highest in terms of consumers applied load pressure to the pump and the delivery rate depending on this highest load pressure set.

    In der Ventilscheibe 2 ist ein stetig verstellbares Wegeventil 4 mit einem die Ansteuerungsrichtung des Verbrauchers bestimmenden Richtungsteil und einem die Meßblende bildenden Geschwindigkeitsteil aufgenommen. Der durch das Wegeventil 4 gebildeten Meßblende (Geschwindigkeitsteil) ist eine Druckwaage 5 nachgeschaltet, deren Regelkolben 40 in seiner Regelstellung den Druckabfall über der Meßblende lastdruckunabhängig konstant hält. Der Ausgangsanschluß der Druckwaage 5 ist hydraulisch mit dem Richtungsteil des Wegeventils 4 verbunden, über den je nach Ansteuerung einer der Arbeitsanschlüsse A, B mit Druckmittel versorgt und der andere mit dem Tankanschluß T verbunden wird. In den Arbeitsleitungen zu den Arbeitsanschlüssen A, B sind stetig verstellbare, entsperrbare Rückschlagventilanordnungen 6, 8 geschaltet, die in ihrer Sperrstellung die Rückströmung vom Verbraucher verhindern und in der entsperrten Durchlaßstellung eine Rückströmung vom entsprechenden Arbeitsanschluß A oder B zum Tankanschluß T hin ermöglichen.In the valve disc 2 is a continuously adjustable Directional control valve 4 with a control direction of the Consumer defining direction and a Speedometer forming orifice plate added. The orifice formed by the directional control valve 4 (Speed section) is connected to a pressure compensator 5, whose control piston 40 in its control position the pressure drop across the orifice independent of the load pressure keeps constant. The output connection of the pressure compensator 5 is hydraulic with the directional part of the directional valve 4 connected, depending on the control one of the Working ports A, B supplied with pressure medium and the another is connected to the tank connection T. In the work lines to the work connections A, B are continuous adjustable, unlockable check valve arrangements 6, 8 switched, the reverse flow in its blocking position prevent from the consumer and in the unlocked Pass position a backflow from the corresponding Working connection A or B towards tank connection T. enable.

    Die Ansteuerung des Wegeventils 4 erfolgt über Pilotventile 10, 12, über die die Stirnseiten eines Wegeventilschiebers 28 des Wegeventils 4 mit einem Steuerdruck beaufschlagbar sind, um diesen aus seiner dargestellten Neutralposition zu verschieben. Der Wegeventilschieber 28 ist durch zwei Druckfedern 30, 32 in seine Neutralposition vorgespannt. Der Regelkolben 40 der Druckwaage 5 ist in Schließrichtung von der Kraft einer Regelfeder 44 und vom höchsten Lastdruck der Verbraucher beaufschlagt, der über einen Lastdruckkanal 22 vom Verbraucher abgegriffen wird. Der Druck stromabwärts des Wegeventils 4 ist über eine Steuerleitung 38 zur in Öffnungsrichtung wirkenden Stirnfläche des Regelkolbens 40 geführt.The directional control valve 4 is activated via Pilot valves 10, 12, through which the end faces of a Directional valve spool 28 of the directional valve 4 with one Control pressure can be applied to this from his to shift the neutral position shown. The Directional valve slide 28 is by two compression springs 30, 32nd biased to its neutral position. The control piston 40 the pressure compensator 5 is in the closing direction of the force a control spring 44 and the highest load pressure Consumer loads through a load pressure channel 22 is tapped by the consumer. The pressure downstream of the directional valve 4 is via a Control line 38 to the one acting in the opening direction End face of the control piston 40 out.

    Die Pilotventile 10, 12 sind stetig verstellbar ausgeführt, so daß ein Druck in der Größenordnung zwischen dem Tankdruck und dem Druck am Pumpenanschluß P an die Stirnseiten des Wegeventilschiebers 28 anlegbar ist. Dieser Steuerdruck wird auch zur Entsperrung der Rückschlagventilanordnungen 6 und 8 verwendet.The pilot valves 10, 12 are continuously adjustable executed so that a pressure of the order between the tank pressure and the pressure at the pump connection P can be applied to the end faces of the directional valve slide 28 is. This control pressure is also used to unlock the Check valve assemblies 6 and 8 used.

    In einem allen Verbrauchern gemeinsamen Abschnitt des Lastdruckkanals 22 ist ein Druckbegrenzungsventil 45 vorgesehen, über das der Lastdruck im Lastdruckkanal 22 begrenzt ist. Das Druckbegrenzungsventil 45 ist in Schließrichtung von einer Feder und in Öffnungsrichtung vom höchsten Lastdruck der Verbraucher beaufschlagt. Bei Überschreiten des Maximaldrucks wird Steueröl zum Tank T hin abgeführt. Der Lastdruckkanal 22 ist des weiteren über eine Tankdrossel 47 mit dem Tank verbunden.In a section of the Load pressure channel 22 is a pressure relief valve 45 provided, via which the load pressure in the load pressure channel 22nd is limited. The pressure relief valve 45 is in Spring closing direction and opening direction acted upon by the highest load pressure of the consumers. at If the maximum pressure is exceeded, control oil becomes tank T dissipated. The load pressure channel 22 is furthermore connected to the tank via a tank throttle 47.

    Figur 2 zeigt eine konkret ausgebildete Ventilscheibe 2, in der die Schaltung gemäß Figur 1 realisiert ist.Figure 2 shows a specifically designed valve disc 2, in which the circuit according to FIG. 1 is implemented.

    Wie bereits erwähnt hat die Ventilscheibe 2 die beiden Arbeitsanschlüsse A, B sowie einen Pumpenanschluß P und den Tankanschluß T, die die Ventilscheibenpackung des Ventilblocks senkrecht zur Zeichenebene durchsetzen. Darüber hinaus ist der höchste Lastdruck aller über den Ventilblock angesteuerten Verbraucher an einen mit dem Lastdruckkanal 22 verbundenen Steueranschluß LS geführt.As already mentioned, the valve disc 2 has the two working connections A, B and a pump connection P and the tank connection T, which is the valve disc packing of the valve block perpendicular to the plane of the drawing. In addition, the highest load pressure is all over the Valve block controlled consumers to one with the Load pressure channel 22 connected control connection LS performed.

    Die Ventilscheibe 2 hat Aufnahmebohrungen für das Wegeventil 4, dessen Wegeventilschieber 28 als Hohlschieber ausgebildet ist. Der in Figur 2 lediglich gestrichelt angedeutete Regelkolben 40 ist im Inneren des Wegeventilschiebers 28 geführt.The valve disc 2 has mounting holes for the Directional control valve 4, the directional control valve 28 as Hollow slide is formed. The only in Figure 2 Dashed piston 40 is inside the Directional valve slide 28 out.

    Parallel zum Wegeventil 4 sind in der Ventilscheibe 2 die beiden entsperrbaren Rückschlagventilanordnungen 6, 8 aufgenommen. Jede der Rückschlagventilanordnungen 6 hat einen mit einer Voröffnung versehenen Hauptkegel 72, der mit einem Aufstoßkolben 92 zusammenwirkt, über den der Hauptkegel 72 zum Entriegeln von seinem Ventilsitz abhebbar ist.Parallel to the directional control valve 4 are 2 in the valve disc the two unlockable check valve arrangements 6, 8 added. Each of the check valve assemblies 6 has a pre-opening main cone 72 which cooperates with an impact piston 92, via which the Main cone 72 for unlocking from its valve seat can be lifted off.

    Die beiden Pilotventile 10, 12 sind in Patronenbauweise ausgeführt und in die in Figur 2 untere Stirnfläche der Ventilscheibe 2 eingeschraubt. Bei den Pilotventilen 10, 12 handelt es sich beispielsweise um elektrisch betätigbare Druckminderventile, über die der Druck am Pumpenanschluß P auf einen Systemdruck am axialen Ausgangsanschluß des jeweiligen Pilotventils 10, 12 reduzierbar ist. Wie aus Figur 1 entnehmbar ist, hat jedes Pilotventil 10, 12 neben dem mit dem Pumpenanschluß P verbundenen Eingangsanschluß noch einen mit dem Tankanschluß T verbundenen Radialanschluß.The two pilot valves 10, 12 are in Cartridge design and in the lower in Figure 2 End face of the valve disc 2 screwed in. Both Pilot valves 10, 12 are, for example electrically operated pressure reducing valves, via which the Pressure at the pump connection P to a system pressure at axial outlet connection of the respective pilot valve 10, 12 is reducible. As can be seen from Figure 1, has each pilot valve 10, 12 next to that with the pump connection P connected input port another one with the Tank connection T connected radial connection.

    Zur Absicherung des Drucks am Tankanschluß T ist in der Ventilscheibe 2 des weiteren ein Rückschlagventil 114 vorgesehen.To secure the pressure at the tank connection T is in a check valve 114 intended.

    Hinsichtlich weiterer Details der Rückschlagventilanordnung 6, 8 und der Pilotventile 10, 12 und deren Funktionsweise sei auf die Druckschrift DE 196 46 428 A1 der Anmelderin verwiesen.For further details of the check valve assembly 6, 8 and the pilot valves 10, 12 and their Operation is based on the publication DE 196 46 428 A1 referred to the applicant.

    Die DE 196 46 428 A1 offenbart eine Ventilanordnung zur Ansteuerung eines doppeltwirkenden Verbrauchers, bei der von einer Pumpe gefördertes Hydraulikfluid über ein Wegeventil wahlweise einem von zwei Arbeitsanschlüssen zuführbar ist, denen jeweils eine Rückschlagventilanordnung zugeordnet ist. Jede Rückschlagventilanordnung wird über ein dieser zugeordnetes Pilotventil angesteuert, dessen Ausgangssteuerdruck auch an einer Stirnseite des Wegeventilschiebers anliegt. Durch Bestromung beider Pilotventile lassen sich der Wegeventilschieber in seiner Nullstellung einspannen und die beiden Rückschlagventilanordnungen entriegeln, so daß die Arbeitsanschlüsse über die Rückschlagventilanordnungen mit einem Tank verbindbar sind und somit eine Schwimmstellung einstellbar ist.DE 196 46 428 A1 discloses a valve arrangement for Actuation of a double-acting consumer at the hydraulic fluid delivered by a pump via a Directional control valve optionally one of two working connections Can be fed, each of which a check valve assembly assigned. Each check valve arrangement is about controlled a pilot valve assigned to this, the Output control pressure also on one end of the Directional valve spool is present. By energizing both Pilot valves can be found in the directional valve spool Clamp the zero position and the two Unlock check valve assemblies so that the Working connections with the check valve arrangements with a tank can be connected and thus a floating position is adjustable.

    Der Aufbau des Wegeventils 4 und der Druckwaage 5 wird im folgenden anhand der Detaildarstellung gemäß Figur 3 beschrieben.The structure of the directional valve 4 and the pressure compensator 5 is in the following based on the detailed representation Figure 3 described.

    Demgemäß hat die Ventilscheibe 2 zur Aufnahme des Wegeventilschiebers 28 eine Ventilbohrung 50, in der sich radial nach außen erstreckende Ringräume 52, 54, 56, 58 und 60 ausgebildet sind. Wie aus Figur 3 entnehmbar ist, ist der Ringraum 52 über eine in Figur 2 gestrichelt angedeutete Lastdruckmeldeleitung 62 mit dem Lastdruckkanal 22 verbunden, der zum Steueranschluß LS geführt ist.Accordingly, the valve disc 2 for receiving the Directional valve slide 28, a valve bore 50 in which Annular spaces 52, 54, 56, 58 extending radially outward and 60 are formed. As can be seen from FIG. 3, the annular space 52 is dashed over a in Figure 2 indicated load pressure signaling line 62 with the Load pressure channel 22 connected to the control connection LS is led.

    Die beiden Ringräume 54 und 56 sind über Arbeitskanäle 66, 68 zu den Arbeitsanschlüssen A bzw. B geführt. The two annular spaces 54 and 56 are over Working channels 66, 68 to the working connections A and B guided.

    Der Ringraum 58 ist einerseits über eine Pumpenleitung 70 mit dem Pumpenanschluß P verbunden und andererseits über einen Verbindungskanal 74 zu einem Radialanschluß der Pilotventile 10, 12 geführt. Der Ringraum 60 ist ebenfalls hydraulisch mit dem Pumpenanschluß P verbunden.The annular space 58 is on the one hand Pump line 70 connected to the pump port P and on the other hand via a connecting channel 74 to one Radial connection of the pilot valves 10, 12 out. The Annulus 60 is also hydraulic with the pump connection P connected.

    Die in Figur 2 dargestellten axialen Ausgangsanschlüsse der Pilotventile 10, 12 sind über Steuerkanäle 76, 78 mit den Federräumen 80, 82 des Wegeventils 4 verbunden. Von dort sind die Steuerkanäle 76, 78 weiter zu den Rückschlagventilanordnungen 6 bzw. 8 geführt.The axial shown in Figure 2 Output connections of the pilot valves 10, 12 are over Control channels 76, 78 with the spring chambers 80, 82 des Directional control valve 4 connected. From there are the control channels 76, 78 further to check valve arrangements 6 and 8 respectively guided.

    Der Wegeventilschieber 28 ist über Druckfedern 30,32 in seine in Figur 3 dargestellte Grundposition vorgespannt.The directional valve slide 28 is 30.32 in via compression springs biased its basic position shown in Figure 3.

    Die beiden Druckfedern 30,32 sind an Verschlußschrauben 90 abgestützt, die die Ventilbohrung 50 in Axialrichtung abschließen.The two compression springs 30, 32 are on locking screws 90 supported, the valve bore 50 in the axial direction to lock.

    Wie eingangs bereits erwähnt, ist der Wegeventilschieber 28 als Hohlkolben ausgeführt und hat eine Axialbohrung 94, die sich in der Darstellung nach Figur 3 vom linken Endabschnitt des Wegeventilschiebers 28 bis in den Bereich des Ringkanals 60 erstreckt. In dieser Axialbohrung 94 mündet ein Meßblenden-Bohrungsstern 96, dessen Durchbrüche als Radialbohrungen im Wegeventilschiebermantel ausgebildet sind. In der dargestellten Grundposition ist der Meßblenden-Bohrungsstern 96 zwischen den beiden Ringräumen 58, 60 angeordnet.As already mentioned at the beginning, the Directional valve slide 28 is designed as a hollow piston and has an axial bore 94, which is shown in the illustration Figure 3 from the left end portion of the directional valve spool 28 extends into the area of the ring channel 60. In this axial bore 94 opens a measuring aperture bore star 96, whose breakthroughs as radial bores are formed in the directional valve spool jacket. In the The basic position shown is the orifice hole star 96 arranged between the two annular spaces 58, 60.

    Im Axialabstand zum Meßblenden-Bohrungsstern 96 ist ein Richtungsbohrungsstern 98 ausgebildet, der in der gezeigten Grundposition zwischen den beiden Ringräumen 54, 56 angeordnet ist.In axial distance from the orifice bore star 96 is a directional bore star 98 formed in the shown basic position between the two annular spaces 54, 56 is arranged.

    Durch die vorbeschriebene Geometrie kann das Druckmittel vom Pumpenanschluß P je nach Ansteuerung des Wegeventilschiebers 28 über die Pumpenleitung 70, den Meßblenden-Bohrungsstern 96, die Axialbohrung 94, den Richtungsbohrungsstern 98 und den Arbeitskanal 66 zum Verbraucher A oder entsprechend über den Ringraum 60, den Meßblenden-Bohrungsstern 96, die Axialbohrung 94, den Richtungsbohrungsstern 98 und den Arbeitskanal 68 zum Verbraucher B geführt werden.Due to the geometry described above, this can be done Pressure medium from the pump connection P depending on the control of the Directional control valve 28 via the pump line 70, the Orifice hole star 96, the axial bore 94, the Directional bore star 98 and the working channel 66 for Consumer A or accordingly via the annular space 60, the Orifice hole star 96, the axial bore 94, the Directional bore star 98 and the working channel 68 for Consumer B are led.

    Der Regelkolben 40 ist innerhalb der Axialbohrung 94 verschiebbar geführt und über die Regelfeder 44 mit einer Ringstirnfläche 100 gegen eine Anschlagschulter der Axialbohrung 94 in seine Schließstellung vorgespannt. Ein Regelkolbenfederraum 104 ist über ein Verbindungsbohrung 106, einer Dämpfungsdrossel 108 und einen Durchbruch 109 im Wegeventilschieber 28 mit dem Ringraum 52 verbunden, so daß der Lastdruck den Regelkolben 40 ebenfalls in Schließrichtung beaufschlagt.The control piston 40 is inside the axial bore 94 slidably guided and via the control spring 44 with a Ring face 100 against a stop shoulder Axial bore 94 biased into its closed position. On Control piston spring chamber 104 is via a connecting bore 106, a damping throttle 108 and an opening 109 connected in the directional valve slide 28 to the annular space 52, so that the load pressure the control piston 40 also in Closing direction applied.

    Gemäß der vergrößerten Darstellung in Figur 4 hat der Regelkolben 40 eine Axialsacklochbohrung 110, die in der rechten (Figur 4) Stirnfläche des Regelkolbens 40 mündet. Im Mündungsbereich ist der Mantel des Regelkolbens 40 radial kronenförmig von Durchbrüchen 112 durchsetzt. In Abstand zu diesen ist ein Kompensationsbohrungsstern 114 ausgebildet, der in der dargestellten Position im Bereich des Ringraums 54 angeordnet ist.According to the enlarged representation in Figure 4, the Control piston 40 an axial blind hole 110 which in the right (Figure 4) end face of the control piston 40 opens. The jacket of the control piston 40 is in the mouth region penetrated radially crown-shaped by openings 112. In A compensation bore star 114 is at a distance from these trained in the position shown in the area of the annular space 54 is arranged.

    Im Bereich zwischen den Durchbrüchen 112 und dem Bohrungsstern 114 ist der Regelkolben 40 radial zurückgestuft, so daß im Bereich der Durchbrüche 112 eine erste Steuerkante 116 und im Bereich des Kompensationsbohrungssterns 110 eine zweite Steuerkante 118 ausgebildet wird.In the area between the openings 112 and the Bore star 114 is the control piston 40 radial downgraded so that a 112 in the area of the openings first control edge 116 and in the area of Compensation bore star 110 a second control edge 118 is formed.

    Der radial zurückgestufte Abschnitt 115 ist im Bereich der ersten Steuerkante 116 als Schrägfläche ausgebildet, während er im Bereich der zweiten Steuerkante 118 als Radialstufe ausgeführt ist.The radially stepped section 115 is in the Area of the first control edge 116 as an inclined surface trained while in the area of the second Control edge 118 is designed as a radial stage.

    Der Wegeventilschieber 28 hat gemäß Figur 4 zwei axial beabstandete Ringnuten 120, 122, die in der Innenumfangsfläche der Axialbohrung 94 ausgebildet sind.The directional valve slide 28 has two according to Figure 4 axially spaced annular grooves 120, 122 which in the Inner peripheral surface of the axial bore 94 are formed.

    Die beiden Ringnuten 120, 122, sind durch einen Mittelsteg 124 voneinander getrennt, der mit der zweiten Steuerkante 118 zusammenwirkt. Die in der Darstellung nach Figur 4 rechte Umfangskante der ersten Ringnut 120 wirkt mit der ersten Steuerkante 116 zusammen, so daß bei Axialverschiebung des Regelkolbens 40 durch Zusammenwirken der ersten Steuerkante 116 und der ersten Ringnut 120 ein Steuerquerschnitt aufgesteuert wird, während durch Zusammenwirken der zweiten Steuerkante 118 und dem Mittelsteg 124 ein Kompensationssteuerquerschnitt geöffnet wird. In der gezeigten Grundposition sind die beiden Steuerquerschnitte geschlossen. Hinsichtlich weiterer Details dieser Kompensationsströmungsführung sei auf die nachveröffent- lichte Anmeldung 198 36 564.0 verwiesen.The two ring grooves 120, 122 are through one Center web 124 separated from each other, the one with the second Control edge 118 cooperates. The one in the illustration 4 right circumferential edge of the first annular groove 120 interacts with the first control edge 116, so that at Axial displacement of the control piston 40 through cooperation the first control edge 116 and the first annular groove 120 a control cross section is opened while by interaction of the second control edge 118 and the Mittelsteg 124 a compensation control cross section is opened. In the basic position shown are the closed both tax cross sections. Regarding further details of this compensation flow guidance on the subsequently published application 198 36 564.0 directed.

    Der Richtungsbohrungsstern 98 mündet in der ersten Ringnut 120. Gemäß Figur 4 ist die Verbindungsbohrung 106 als Winkelbohrung ausgeführt, wobei ein Radialbohrungsschenkel 126 der Verbindungsbohrung 106 im Durchbruch 109 des Wegeventilschiebers 28 mündet. Der Radialbohrungsschenkel 126 ist so angeordnet, daß die Verbindung zwischen dem Ringkanal 52 und dem Federraum 104 über dem gesamten Hub des Regelkolbens 40 geöffnet ist. D. h., der Regelkolben 40 wird in Schließrichtung stets durch die Kraft der Regelfeder 44 und den Lastdruck im Lastdruckkanal 22 beaufschlagt.The directional bore star 98 opens into the first Ring groove 120. According to FIG. 4, the connecting bore 106 designed as an angle bore, with a radial bore leg 126 of the connection bore 106 in the opening 109 of the directional control valve 28 opens. The radial bore leg 126 is arranged so that the connection between the ring channel 52 and the spring chamber 104 over the entire Stroke of the control piston 40 is open. That is, the Control piston 40 is always in the closing direction by the Force of the control spring 44 and the load pressure in the load pressure channel 22 acted upon.

    Die Axialbohrung 110 des Regelkolbens 40 mündet an ihrem linken Endabschnitt in einer Düsenbohrung 128, die ihrerseits in einer Radialbohrung 130 des Regelkolbens 40 übergeht.The axial bore 110 of the control piston 40 opens its left end portion in a nozzle bore 128, the in turn in a radial bore 130 of the control piston 40 transforms.

    In der dargestellten Grundposition des Regelkolbens 40 ist die Radialbohrung 130 durch die Innenumfangswandung des Wegeventilschiebers 28 verschlossen. Bei einer Axialverschiebung des Regelkolbens 40 gegenüber dem Wegeventilschieber 28 wird die Radialbohrung 130 durch eine Steuerkante 132 aufgesteuert, die durch den Durchbruch 109 im Wegeventilschiebermantel ausgebildet ist. D. h., bei Bewegung des Regelkolbens 40 gegen die Kraft der Regelfeder 44 und den im Federraum herrschenden Steuerdruck wird der Druck stromabwärts der Meßblende in den Lastdruckkanal 22 und damit auch in den Federraum 104 gemeldet. Der Durchmesser der Düsenbohrung 128 ist wesentlich kleiner als der entsprechende Verbindungsquerschnitt bei den eingangs genannten, herkömmlichen Druckwaagen. Letztere waren stets so ausgelegt, daß über dieser Verbindungsbohrung nur ein vernachlässigbarer Druckabfall erfolgt, so daß der Lastdruck bei vollständig aufgesteuertem Regelkolben 46 unverfälscht zur Regelpumpe gemeldet wird.In the basic position of the control piston shown 40 is the radial bore 130 through the inner peripheral wall of the directional control valve 28 closed. At a Axial displacement of the control piston 40 relative to the directional valve spool 28, the radial bore 130 through a Control edge 132 opened by the breakthrough 109 is formed in the directional valve spool jacket. That is, when the control piston 40 moves against the force of the control spring 44 and the control pressure prevailing in the spring chamber the pressure downstream of the orifice plate into the load pressure channel 22 and thus also reported in the spring chamber 104. The diameter of the nozzle bore 128 is essential smaller than the corresponding connection cross section at the conventional pressure compensators mentioned at the beginning. Latter were always designed so that this connection hole there is only a negligible drop in pressure, so that the load pressure when fully open Control piston 46 is reported to the control pump in an unadulterated manner becomes.

    Durch den erfindungsgemäß ausgebildeten, geringen Öffnungsquerschnitt der Düsenbohrung 128 wird die bei geöffnetem Druckbegrenzungsventil 45 aus dem Lastdruckkanal 22 zum Tank T strömende Steuerölmenge reduziert, so daß das Ansprechverhalten und der Wirkungsgrad der hydraulischen Steuerung verbessert werden. Due to the low trained according to the invention The opening cross section of the nozzle bore 128 is that when the opening is open Pressure relief valve 45 from the load pressure channel 22 to the tank T flowing control oil quantity reduced so that the responsiveness and efficiency of the hydraulic Control can be improved.

    Die Regelfeder 44 ist beim gezeigten Ausführungsbeispiel mit einer großen Vorspannung oder einer großen Federsteifigkeit ausgeführt, so daß etwa der halbe Stand-By-Druck der Verstellpumpe aufgebracht werden muß, um den Regelkolben 40 gegen die Kraft der Regelfeder 44 zu verschieben. D. h., bei einem Stand-By-Druck von etwa 20 bar, der bei der gezeigten Schaltung zur Betätigung der Pilotventile 10, 12 benötigt wird, ist die Regelfeder 44 etwa als 10-bar-Feder ausgebildet. Die Druckmittelströmung entlang des Regelkolbens 44 ist durch geeignete geometrische Ausgestaltung des eingangs beschriebenen Steuerquerschnittes und des in entgegengesetzter Richtung wirkenden Kompensations- steuerquerschnittes so ausgelegt, daß die Resultierende aus der Kraft der Regelfeder 44 und den auf den Regelkolben wirkenden Strömungskräften eine vom Regelkolbenhub unabhängige Konstante ist. Mit anderen Worten gesagt, die Regelfeder 44 und die Strömungskräfte werden derart aufeinander abgestimmt, daß sich im Ergebnis eine horizontale Federkennlinie einstellt, bei der die Federkraft unabhängig vom Hub des Regelkolbens 40 ist.The control spring 44 is in the embodiment shown with a large preload or a high spring stiffness executed so that about half the stand-by pressure the variable pump must be applied to the Shift control piston 40 against the force of the control spring 44. That is, at a stand-by pressure of about 20 bar, which in the circuit shown for actuating the Pilot valves 10, 12 is required, the control spring 44th designed as a 10 bar spring. The pressure medium flow along the control piston 44 is by suitable geometric Design of the control cross section described at the beginning and in the opposite direction effective control cross-section designed so that the resultant from the force of the control spring 44 and the flow forces acting on the control piston is a constant that is independent of the control piston stroke. With in other words, the control spring 44 and the flow forces are coordinated so that the result is a horizontal spring characteristic, where the spring force is independent of the stroke of the control piston 40 is.

    Zum besseren Verständnis sei die Funktion der erfindungsgemäßen Steueranordnung erläutert. Zunächst sei angenommen, daß lediglich ein einziger Verbraucher über den Ventilblock mit Druckmittel versorgt werden soll. Dazu werden die Pilotventile 10, 12 entsprechend angesteuert, so daß eine Steuerdruckdifferenz auf die Stirnseiten des Wegeventilschiebers 28 wirkt. Entsprechend dieser Steuerdruckdifferenz wird der Wegeventilschieber 28 aus seiner federvorgespannten Grundposition herausbewegt, so daß der Meßblenden-Bohrungsstern 96 beispielsweise durch eine Steuerkante 133 aufgesteuert wird. Entsprechend wird durch die Axialverschiebung des Wegeventilschiebers 28 auch der Richtungsbohrungsstern 98 aufgesteuert, so daß der Arbeitskanal 66 mit Druckmittel aus der Pumpe versorgt wird und der Arbeitskanal 68 mit dem Tankanschluß T verbunden wird.For a better understanding, the function of the invention Control arrangement explained. First, let's assume that only a single consumer about the Valve block to be supplied with pressure medium. To the pilot valves 10, 12 are activated accordingly, so that a control pressure difference on the end faces of the Directional valve slide 28 acts. According to this control pressure difference the directional valve slide 28 from his spring-biased basic position moved out so that the Orifice hole star 96, for example by a Control edge 133 is opened. Accordingly by the axial displacement of the directional valve slide 28 also opened the directional bore star 98, so that the working channel 66 is supplied with pressure medium from the pump and the working channel 68 with the tank connection T is connected.

    Das Druckmittel tritt durch den aufgesteuerten Meßblendenbohrungsstern 96 in die Axialbohrung 94 ein, so daß der Regelkolben 40 der Druckwaage gegen die Kraft der Regelfeder 44 in Öffnungsrichtung beaufschlagt ist. Durch den Druckaufbau am Eingang der Druckwaage 5 wird der Regelkolben 40 in seine in Figur 3 linke Endposition gebracht, so daß der Kompensationsquerschnitt und der Steuerquerschnitt vollständig auf gesteuert sind. Dabei wird über die Steuerkante 132 die Radialbohrung 130 aufgesteuert, so daß der Druck am Eingang der Druckwaage 5 über die Axialsacklochbohrung 110, die Düsenbohrung 128, die Radialbohrung 130 und den Durchbruch 109 in die Lastdruckmeldeleitung 62 und damit in den Lastdruckkanal 22 gemeldet wird. Dieser in den Lastdruckkanal 22 gemeldete Lastdruck ist allerdings entsprechend der Kraft der Regelfeder 44 niedriger als der am Eingang der Druckwaage und im Arbeitskanal 66 herrschende Lastdruck. Die Verstellpumpe wird dann in Abhängigkeit von diesem niedrigeren Lastdruck angesteuert.The pressure medium passes through the open orifice hole star 96 in the axial bore 94, see above that the control piston 40 of the pressure compensator against the force of the Control spring 44 is acted upon in the opening direction. By the pressure build-up at the inlet of the pressure compensator 5 becomes the control piston 40 brought into its left end position in FIG. 3, so that the compensation cross section and the control cross section are fully controlled on. Doing so the radial bore 130 is opened via the control edge 132, so that the pressure at the input of the pressure compensator 5 over the axial blind bore 110, the nozzle bore 128, the Radial bore 130 and the opening 109 in the load pressure reporting line 62 and thus into the load pressure channel 22 is reported. This reported in the load pressure channel 22 However, load pressure corresponds to the force of the control spring 44 lower than that at the inlet of the pressure compensator and load pressure prevailing in working channel 66. The variable pump then becomes lower depending on this Load pressure controlled.

    Der Deutlichkeit halber sei dies nochmals an einem Zahlenbeispiel erläutert. Es sei angenommen, daß der Stand-By-Druck der Verstellpumpe 20 bar beträgt. Der Lastdruck am Eingang der Druckwaage, d. h. im Arbeitskanal 66, soll beispielsweise 200 bar betragen. Die Regelfeder 44 ist als sogenannte 10-bar-Feder (unabhängig vom Hub) ausgelegt. D. h., bei vollständig aufgesteuerter Druckwaage wird dann in den Lastdruckkanal 22 ein Druck von 200 bar - 10 bar = 190 bar gemeldet. Die Pumpe wird dann entprechend auf 210 bar eingeregelt, so daß der Druckabfall über der Meßblende lediglich noch 10 bar beträgt. For the sake of clarity, this is again one Numerical example explained. It is assumed that the Stand-by pressure of the variable pump is 20 bar. The Load pressure at the inlet of the pressure compensator, d. H. in the working channel 66, for example, should be 200 bar. The rule spring 44 is a so-called 10 bar spring (regardless of Stroke). That is, with the fully open Pressure compensator is then a pressure in the load pressure channel 22 from 200 bar - 10 bar = 190 bar reported. The pump will then adjusted accordingly to 210 bar, so that the Pressure drop across the orifice plate is only 10 bar.

    Bei den herkömmlichen Systemen würde aufgrund der schwachen Regelfeder 44 ein Lastdruck zur Regelpumpe gemeldet werden, der dem Druck am Eingang der Druckwaage entspricht, d. h. die Pumpe würde beim Stand der Technik auf 220 bar eingeregelt, so daß der Druckabfall über der Meßblende 20 bar betragen würde. Durch die erfindungsgemäße Auslegung der Druckwaage läßt sich somit eine erhebliche Energieeinsparung bewirken, da der Druckabfall über der Meßblende bei vollständig aufgesteuerter Druckwaage 5 verringert wird.In the conventional systems, due to the weak control spring 44 reported a load pressure to the control pump be the pressure at the inlet of the pressure compensator corresponds, d. H. the pump would be in the prior art adjusted to 220 bar so that the pressure drop across the Orifice plate would be 20 bar. By the invention Design of the pressure compensator can thus be considerable Saving energy because the pressure drop over the orifice plate with the pressure compensator fully open 5 is reduced.

    Für den Fall, daß nun über den Ventilblock ein zweiter hydraulischer Verbraucher betätigt wird, dessen Lastdruck größer als derjenige des vorbeschriebenen Verbrauchers ist, so wird die dem zweiten Verbraucher zugeordnete Druckwaage vollständig aufgesteuert und dieser Lastdruck in den Lastdruckmeldekanal gemeldet und die Regelpumpe entsprechend angesteuert. Durch den in Schließrichtung wirkenden höheren Druck wird der Regelkolben 40 des vorbeschriebenen Verbrauchers in seine Regelposition verschoben, in der die Steuerkante 132 die Radialbohrung 130 zugesteuert hat. In dieser Regelposition liegt am Eingang der Druckwaage der höhere Lastdruck des zweiten Verbrauchers an. Dieser Druck wird über die Druckwaage abgedrosselt, so daß am Druckwaagenausgang (Arbeitskanal 66) der niedrigere Lastdruck des ersten Verbrauchers anliegt. D. h., über den dem ersten und dem zweiten Verbraucher zugeordneten Meßblenden fällt jeweils die gleiche Druckdifferenz von etwa 10 bar ab.In the event that a second via the valve block hydraulic consumer is operated, its load pressure larger than that of the consumer described above is the one assigned to the second consumer Pressure compensator fully opened and this load pressure reported in the load pressure reporting channel and the control pump controlled accordingly. By in the closing direction acting higher pressure is the control piston 40 of shifted the previously described consumer into its control position, in which the control edge 132 the radial bore 130 has contributed. In this control position is at the entrance the pressure compensator the higher load pressure of the second consumer on. This pressure is throttled over the pressure compensator, so that at the pressure compensator outlet (working channel 66) lower load pressure of the first consumer is present. D. that is, via the one assigned to the first and the second consumer Orifice plates have the same pressure difference from about 10 bar.

    Wie bereits eingangs erwähnt wurde, wird durch das Vorsehen der Düsenbohrung 128 der Steuerölstrom über das Druckbegrenzungsventil zum Tank aufgrund des erhöhten hydraulischen Widerstandes minimiert, so daß die Verluste der Anlage auf ein Minimum reduziert sind. As already mentioned at the beginning, the Providing the nozzle bore 128 of the control oil flow over the Pressure relief valve to the tank due to the increased hydraulic Resistance minimized, so that the losses the system are reduced to a minimum.

    Anstelle der vorbeschriebenen Verstellpumpe könnte auch eine Konstantpumpe mit 3-Wege-Stromregelventil eingesetzt werden.Instead of the variable pump described above a constant pump with 3-way flow control valve is also used become.

    Offenbart sind ein Verfahren und eine Steueranordnung zur Ansteuerung zumindest eines hydraulischen Verbrauchers. Die Steueranordnung hat eine Pumpe, deren Leistung in Abhängigkeit vom Lastdruck eines Verbrauchers einstellbar ist. Dessen Ansteuerung erfolgt über ein eine Meßblende bildendes Proportionalwegeventil, dem eine Druckwaage zugeordnet ist, über die der Druckabfall über der Meßblende lastdruckunabhängig konstant gehalten wird. Erfindungsgemäß wird bei vollständig geöffneter Druckwaage ein niedrigerer Lastdruck zur Pumpe gemeldet, so daß der Druckabfall über der Meßblende verringert wird.A method and a control arrangement are disclosed to control at least one hydraulic consumer. The control arrangement has a pump whose output adjustable depending on the load pressure of a consumer is. Its control takes place via a Proportional directional control valve, one Pressure compensator is assigned, via which the pressure drop over the orifice plate is kept constant regardless of the load pressure. According to the invention, when the pressure compensator is fully open a lower load pressure to the pump is reported, so that the pressure drop across the orifice plate is reduced.

    Claims (10)

    1. A method for driving a consumer through a control arrangement, having a pump whose output is controlled as a function of a control pressure in a control pressure channel (22) in such a way that the pump pressure is above the control pressure by a predetermined pressure differential, and a directional valve (4) forming a measuring orifice and having a directional valve slide (28) in which a control piston (40) of a pressure compensator (5) is slidably mounted, through which the pressure drop across the measuring orifice is kept constant irrespective of the load pressure of a consumer, the pressure downstream of the measuring orifice being applied to the control piston (40) in the opening direction and a control spring (44) and the control pressure being applied to the control piston (40) in the closing direction, and the pressure downstream of the measuring orifice being indicated to the control pressure channel (22) when the pressure compensator (5) is completely opened, characterized in that when the pressure compensator (5) is completely opened a pressure is indicated to the control pressure channel (22) which is substantially lower however lower by less than the predetermined pressure differential than the load pressure of the consumer.
    2. A control arrangement for driving at least one hydraulic consumer, having a pump whose pump pressure is adjustable as a function of a control pressure in a control pressure channel (22) in such a way that the pump pressure is higher than the control pressure by a predetermined pressure differential, having a directional valve (4) for driving the consumer, the directional valve (4) forming a measuring orifice and having a directional valve slide (28), in which a control piston (40) of a pressure compensator (5) is slidably mounted, through which the pressure drop across the measuring orifice can be maintained constant irrespective of the load pressure of a consumer, and to which the pressure downstream of the measuring orifice is applied in the opening direction and to which a control spring (44) and the control pressure is applied in the closing direction, wherein the pressure downstream of the measuring orifice may be indicated to the control pressure channel (22) when the pressure compensator (5) is completely opened, characterized in that the spring constant and/or the bias of the control spring (44) are dimensioned such that when the pressure compensator (5) is completely opened a load pressure of the consumer is indicated to the pump which is substantially reduced however reduced by less than the predetermined pressure differential.
    3. A control arrangement according to claim 2, characterized in that the spring force of the control spring (44) corresponds to about half the pressure force corresponding to said pressure differential.
    4. A control arrangement according to claim 2 or 3, characterized in that the pressure fluid flow is controlled in such a way that the flow forces acting on the control piston (40) in combination with the force of the control spring (44) exert an approximately constant force on the control piston (40) throughout the control piston stroke.
    5. A control arrangement according to claim 4, characterized in that the control piston (40) comprises two control edges (116, 118) allowing a control cross section or a compensating cross section to be driven, enabling pressure fluid flows to be caused acting in the opposite direction.
    6. A control arrangement according to any one of claims 2 to 5, characterized in that the control piston (40) comprises a nozzle bore (128) through which a connection between a space downstream of the measuring orifice to the control pressure channel (62, 22) may be opened up, in which a pressure limiting valve (45) is disposed for limiting the control pressure.
    7. A control arrangement according to claim 6, characterized by a communication bore (106), through which the spring chamber (104) of the control piston (40) is connectable with the control pressure channel (62, 22).
    8. A control arrangement according to claim 7, characterized in that a damping nozzle (108) is provided in the communication bore (106).
    9. A control arrangement according to any one of claims 2 to 8, characterized in that the pressure differential corresponds to about 20 bar and the force of the control spring (44) corresponds to about 10 bar.
    10. A control arrangement according to any one of claims 2 to 9, characterized in that the pump is a constant pump having an input pressure compensator, or is a variable pump.
    EP99963215A 1998-11-30 1999-11-11 Method and control device for controlling a hydraulic consumer Expired - Lifetime EP1135613B1 (en)

    Applications Claiming Priority (3)

    Application Number Priority Date Filing Date Title
    DE19855187A DE19855187A1 (en) 1998-11-30 1998-11-30 Method and control arrangement for controlling a hydraulic consumer
    DE19855187 1998-11-30
    PCT/DE1999/003601 WO2000032944A1 (en) 1998-11-30 1999-11-11 Method and control device for controlling a hydraulic consumer

    Publications (2)

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    EP1135613A1 EP1135613A1 (en) 2001-09-26
    EP1135613B1 true EP1135613B1 (en) 2003-04-09

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    US (1) US6516614B1 (en)
    EP (1) EP1135613B1 (en)
    DE (2) DE19855187A1 (en)
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    Also Published As

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    US6516614B1 (en) 2003-02-11
    DE59905000D1 (en) 2003-05-15
    DE19855187A1 (en) 2000-05-31
    WO2000032944B1 (en) 2000-08-31
    WO2000032944A1 (en) 2000-06-08
    EP1135613A1 (en) 2001-09-26

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