EP0758056B1 - Method to control a hydraulic actuator and hydraulic control system for carrying out said method - Google Patents

Method to control a hydraulic actuator and hydraulic control system for carrying out said method Download PDF

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Publication number
EP0758056B1
EP0758056B1 EP96111864A EP96111864A EP0758056B1 EP 0758056 B1 EP0758056 B1 EP 0758056B1 EP 96111864 A EP96111864 A EP 96111864A EP 96111864 A EP96111864 A EP 96111864A EP 0758056 B1 EP0758056 B1 EP 0758056B1
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EP
European Patent Office
Prior art keywords
pressure
load
throttle
opening
line
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
EP96111864A
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German (de)
French (fr)
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EP0758056A2 (en
EP0758056A3 (en
Inventor
Rudolf Obering. Brunner
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Hawe Hydraulik GmbH and Co KG
Original Assignee
Heilmeier and Weinlein Fabrik fuer Oel Hydraulik GmbH and Co KG
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Publication of EP0758056A2 publication Critical patent/EP0758056A2/en
Publication of EP0758056A3 publication Critical patent/EP0758056A3/en
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    • 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
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • 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
    • F15B11/003—Systems with 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/01—Locking-valves or other detent i.e. load-holding devices

Definitions

  • the invention relates to a method in the preamble of Claim specified type and a hydraulic Control device for performing the method according to the Preamble of claim 7.
  • the pressure on the control piston corresponds to that from the other Working line derived control pressure. Since the Load pressure in the same direction as the control piston on Closing element of the load holding valve, i.e. in the opening direction and acts against the spring load, is at high load pressure only a low pressure on the control piston is required, in contrast, a very high pressure at low load pressure. This complicates sensitive movement control of the hydro consumer by means of the load holding valve under the load, and both at high load and at low load, because the overall system of the hydraulic circuit is then not stiff enough is.
  • a hydraulic control device with at least one load holding valve in a working line of the hydro consumer, in which in the from the other Working line to the control piston led control pressure line a hydraulic damping device for pressure fluctuations is provided in the system, which consists of a in the control pressure line arranged throttle passage, one of the Control pressure line branching drain line and another Throttle passage in the drain line exists.
  • a hydraulic damping device for pressure fluctuations is provided in the system, which consists of a in the control pressure line arranged throttle passage, one of the Control pressure line branching drain line and another Throttle passage in the drain line exists.
  • this Damping device is permanently due to the throttle arrangement outflowing pressure medium an improved damping achieved.
  • the pressure on the control piston is less is than the control pressure generated in the other working line, the pilot pressure changes indirectly proportionally to load pressure. At high load pressure there is a lower one Opening pressure, while at low load a high one Control pressure is required.
  • the damping device provides a predeterminable hydraulic reduction between the control pressure in the other working line and
  • DE 39 11 022 A1 relates to a hydraulic control device for one-sided via a 4/3-way valve from a single Working line against a loadable lifting cylinder, with a load-holding shut-off valve that is used to lower the load can be unlocked hydraulically via an actuator.
  • the pressurizable control line is connected to an actuator for adjusting the directional valve between a lower position, a shut-off position and a lifting position and also on the actuator for unlocking the check valve is connected.
  • a reset device of the actuator of the check valve extended control line two chokes are provided, between which a relief line to the directional control valve branches off in the lowering and in the locked position of the Directional control valve to the tank is relieved.
  • the check valve is at a predetermined Unlocked pressure value, which is after the pressurized area of the actuator and the force of the closing spring of the Check valve directed.
  • the pressure variations of the control line are used to adjust the directional control valve against spring force between its switching positions and for volume flow control used for the lifting cylinder.
  • the invention has for its object a method of type mentioned and a hydraulic control device to carry out the procedure by which the Movement of the hydraulic consumer controlled by the load holding valve controllable under load regardless of the size of the load is.
  • the setting of the pilot pressure achieved directly proportional to the load pressure that at high load a high pilot pressure and at low Load results in a low pilot pressure.
  • the hydraulic control device then stiff.
  • the movement of the hydro consumer can be controlled sensitively, because at low load of the hydraulic consumers with low pilot pressure and controlled at high load with high pilot pressure becomes.
  • An effective one can then be used, especially at high loads Achieve damping of pressure fluctuations in the system because a large control pressure medium volume is moved. Doing so a load pressure-dependent adjustment of a hydraulic reduction between the control pressure in the other working line and the effective pressure on the control piston.
  • the hydraulic control device is over the throttle arrangement and the drain line depending on the level of the load pressure more or less pressure medium exactly controlled drained.
  • the method variant according to claim 2 is useful because the pressure reduction is only carried out in the control circuit, so that there is no noticeable influence on the other work management the movement speed of the Hydro consumer enters.
  • the opening pressure in direct dependence on the load pressure continuously to adjust. It will be one for each load size optimal pilot pressure enables.
  • control pressure graded adjust, expediently in at least one Step.
  • the respective Variable throttle through the load pressure which is proportional to the load pressure Pressure or one derived from the load pressure electrical signal or via a mechanical adjustment device sensitively adjusted to take into account the just at the control piston necessary pressure in the other Working line adjust the pilot pressure so that this enables sensitive movement of the hydro consumer.
  • pilot pressure is gradually adjusted by increasing Load pressure switched on at least one further throttle passage becomes.
  • the embodiment for connection or disconnection is structurally simple at least one further throttle passage according to claim 10.
  • the throttle passage can be switched on or off in Activated or deactivated depending on the level of the load pressure.
  • the adjustment device can be in accordance with the embodiment Claim 11 on hydraulic, electrical or mechanical Press away. Hydraulically, the Load pressure or the respective adjustment signal from the pilot pressure derived. Electrically, e.g. about a pressure measuring device or a pressure switch from which Load pressure an electrical signal for the adjustment device generated that makes the adjustment of the throttle arrangement. Mechanically, one could use one of load pressure or else the lever mechanism or gear which can be actuated by the opening pressure the respective setting can be made.
  • the embodiment according to claim is particularly advantageous 12.
  • the adjustable throttle arrangement leads together with the Drain line in addition to the pressure reduction the additional task damping of pressure vibrations in the system because by means of the control pressure medium volume guided via the throttle arrangement the peaks and valleys of pressure vibration amplitudes cut and the pressure fluctuations quickly be dampened. Because the hydraulic reduction and the Damping only in the control circuit and with the control pressure medium the associated losses are negligible, especially when the outgoing control pressure medium returned to the unpressurized working line becomes.
  • a hydraulic control device S according to FIG. 1 is used for Motion control of a hydro consumer Z, for example a double-acting hydraulic cylinder with differential piston 1, the two pressurized spaces indicated by 2 and 3 are.
  • the hydro consumer Z is, for example, by a Load L is applied in the direction of the arrow indicated in the Room 3 causes a certain load pressure LD.
  • the hydro consumer Z is via working lines 4 and 5 and a directional control valve W optionally to a pressure source P or a return or tank T can be connected.
  • a hydraulically openable Load holding valve H is arranged, which is a closing element 7 in the closing direction on a seat 8, preferably adjustable spring 6 as well as a pressure P9 Control piston 9 has.
  • the load pressure LD acts against the force of the spring 6 in the seat 8 on the closing element 7.
  • the control piston 9 acts also against the force of the spring 6.
  • a control pressure line 11 branches at point 10 to the control piston 9, via which in the other working line 4 controlled control pressure AD converted to the pressure P9 that correspond to the opening pressure AD, but also can be much lower.
  • a hydraulic damping device D included with the pressure vibrations in the system and can be damped for the control piston 9.
  • Part of the damping device D is expediently adjustable Damping throttle 12 with in the opening direction of the opening piston 9 the damping throttle 12 immediate check valve 13 between a branch 14 of a drain line 15 and the control piston 9 are arranged.
  • a throttle passage 16 (indicated by dashed lines as an adjusting throttle), the together with a discharge throttle passage 17 (also as a variable throttle indicated by dashed lines) in the drain line 15 a adjustable throttle arrangement A forms, for their adjustment an adjusting device C is provided.
  • the drain line 15 is either connected to the tank T or to a working line 5 (not shown).
  • the load holding valve H is in Flow direction to the hydro consumer Z through a line loop 5a can be bypassed, in which an opening to the hydro consumer Z Check valve R is arranged.
  • the adjustment device C is connected to the pilot line 18 a working line 5 connected so that the load pressure in Room 3 is always available in the adjustment device C. is dependent on the adjustable throttle arrangement A. to adjust the height of the load pressure LD so that at high Load pressure more pressure medium discharged via the drain line 15 is considered at low load pressure. At low load pressure even the discharge throttle 17 can be closed completely.
  • the adjustment device C could also be adjusted electrically, for example via an electric Pressure gauge 22 (or a pressure switch) for the Load pressure via a signal line 23 with the adjusting device C is connected. Even a mechanical transmission of a signal dependent on the load pressure to the adjusting device C would be possible.
  • the hydraulic control device is in the position shown in the neutral position.
  • the hydro consumer Z stands.
  • the load pressure is from the load holding valve H and from the check valve R added. If the directional control valve W from the shown neutral position to the left, then the Pressure source P with one working line 5 and the other working line 4 connected to the tank T.
  • the hydraulic motor Z is moved in the lifting direction via the opening check valve R. The speed of movement is e.g. according to the extent the adjustment of the directional control valve W.
  • the extended Pressure medium from room 2 is via the other working line 4 passed to the tank T.
  • the control piston 9 remains without noticeable Impingement.
  • the directional control valve W is from the neutral position shown adjusted to the right, then the other work line 4 with the pressure source P and the one working line 5 with the Tank connected. In the other working line 4 is at the point 10 a pilot pressure AD built up, which also in room 2 of the hydraulic consumer Z works. Via the control pressure line 11 and the adjustable throttle arrangement A, the pilot pressure AD the pressure P9 dependent on the respective load pressure LD is reduced, wherein the adjusting device C is operated depending on the load pressure is that, at high load pressure, a high pilot pressure AD, however at low load pressure LD, a lower pilot pressure AD is controlled.
  • control piston controls 9, the load holding valve H, so that the pressure medium flows out of the one working line 5 and, e.g. the on Directional control valve W, set movement speed reached becomes.
  • the pilot pressure AD is before the start of the movement Hydraulic motor Z, i.e. before opening the load holding valve H, set.
  • the diagram in FIG. 7 shows how the opening pressure AD in relation to the load pressure LD for different loads (vL) is set such that at high load pressure LD a high pilot pressure AD and a smaller load pressure LD also a smaller pilot pressure is set. Even though this is not shown, could at a low load pressure Opening pressure may even be higher than the load pressure.
  • the adjustment the control pressure depending on the respective Load pressure is expediently continuously or, if necessary, gradually, i.e. in at least one stage.
  • the Fig. 2-4 show embodiments for continuous change the control pressure. 5 and 6 allow, however, a gradual change in the pilot pressure.
  • the throttle passage 16 is in the control pressure line 11 used with a fixed passage size.
  • the discharge throttle passage 17 'formed as an adjustment throttle from the pilot line 18 or 18 'with increasing load pressure can increase in their passage size. At low The throttle 17 'can even be completely closed under load pressure become.
  • the throttle passage 16 ' is in the control pressure line 11 is designed as an adjusting throttle 16 ', which extends over the Pilot line 18 or 18 'can be adjusted such that with increasing Load pressure the passage size is reduced.
  • the drain throttle passage 17 in the drain line 15, however, is with fixed passage size arranged.
  • the throttle passages 16 'and 17' are variable throttles trained and via the pilot line 18 or 18 ' adjustable in opposite directions, i.e. the adjusting throttle 16 is with increasing load pressure reduced in their passage size, however, the adjusting throttle 17 'with increasing load pressure in their passage size increased.
  • the respective variable throttle 17 ', 16' could also be electrical or mechanical Signal can be adjusted.
  • the drain throttle passage 17 is a line loop 19 in the drain line 15th bypassed in which a valve 20, e.g. one in the outflow direction opening check valve, and another downstream Throttle passage 17 "are provided.
  • a valve 20 e.g. one in the outflow direction opening check valve
  • an adjusting device C for the throttle arrangement A is a blocking element 21 provided that connected to the pilot line 18 or 18 ' is and at higher load pressure, the valve 20 unlocked, so that the further throttle passage 17 "is switched on. It would be also conceivable, the adjusting device C by means of an electrical Signal or by mechanical means (indicated at 24) to adjust accordingly.
  • throttle passages 16 or 17 are also be provided.
  • the throttle passages 16 or 17 are variable chokes according to the Fig. 2 to 4 to train and adjust. (Restrictor combination with variable throttles and fixed throttles).
  • FIG. 6 which in the function of 5 corresponds to the locking device 21 'by an electrical signal in line 23 (s. Fig.1) actuated with the help of a switching magnet 25 to the Open valve 20 at high load pressure and at low Lock load pressure.
  • FIG. 6 could also several additional drain throttle passages 17 "may be provided. 5 and 6, the throttle passage 16 can have a diameter of 0.5 mm and each throttle passage 17, 17 "one Have a diameter of 0.4 mm.

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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)
  • Hydraulic Control Valves For Brake Systems (AREA)
  • Forklifts And Lifting Vehicles (AREA)

Abstract

The load hold valve has a closure component spring-loaded and activated in the opening direction by the load pressure of the hydraulic user and a control piston for the closure component activated with pressure against the spring loading. The closure component activation pressure is fed by a control pressure into the other work conduit. Before the commencement of the control of the load hold valve (H) the ratio between the load pressure (LD) and the control pressure (A) is adjusted proportionally to the load pressure in such a way that at high load pressure a high control pressure appertains, and at low load pressure a low control pressure.

Description

Die Erfindung betrifft ein Verfahren der im Oberbegriff des Patentanspruchs 1 angegebenen Art sowie eine hydraulische Steuervorrichtung zur Durchführung des Verfahrens gemäß dem Oberbegriff des Patentanspruchs 7.The invention relates to a method in the preamble of Claim specified type and a hydraulic Control device for performing the method according to the Preamble of claim 7.

Bei einem aus DE-OS 25 59 029 bekannten Verfahren dieser Art entspricht der Druck auf dem Aufsteuerkolben dem aus der anderen Arbeitsleitung abgeleiteten Aufsteuerdruck. Da der Lastdruck in der gleichen Richtung wie der Aufsteuerkolben am Schließelement des Lasthalteventils, d.h. in Öffnungsrichtung und gegen die Federbelastung, wirkt, ist bei hohem Lastdruck nur ein niedriger Druck auf den Aufsteuerkolben erforderlich, hingegen bei niedrigem Lastdruck ein sehr hoher Druck. Dies erschwert eine feinfühlige Bewegungssteuerung des Hydroverbrauchers mittels des Lasthalteventils unter der Last, und zwar sowohl bei hoher Last als auch bei niedriger Last, da das Gesamtsystem des Hydraulikkreises dann nicht steif genug ist. Außerdem ist speziell bei hoher Last die Dämpfung von Druckschwankungen bzw. Lastbewegungen schwierig, da - wie gesagt - der in der anderen Arbeitsleitung aufzubauende Aufsteuerdruck ziemlich genau dem am Aufsteuerkolben wirkenden Druck entspricht und bei niedrigem Aufsteuerdruck nur ein kleines zum Dämpfen nutzbares Steuerdruckmittelvolumen strömt. Eigentlich ist diese Funktion technisch nicht sinnvoll bzw. verkehrt, weil gerade bei hoher Last zum Bewegen des Hydroverbrauchers ein hoher Aufsteuerdruck besser, hingegen bei niedriger Last ein niedriger Aufsteuerdruck besser wäre.In a method of this type known from DE-OS 25 59 029 the pressure on the control piston corresponds to that from the other Working line derived control pressure. Since the Load pressure in the same direction as the control piston on Closing element of the load holding valve, i.e. in the opening direction and acts against the spring load, is at high load pressure only a low pressure on the control piston is required, in contrast, a very high pressure at low load pressure. This complicates sensitive movement control of the hydro consumer by means of the load holding valve under the load, and both at high load and at low load, because the overall system of the hydraulic circuit is then not stiff enough is. In addition, the damping of Pressure fluctuations or load movements difficult because - as I said - the control pressure to be built up in the other working line pretty much the one that acts on the control piston Pressure corresponds and only at low pilot pressure small control pressure medium volume usable for damping flows. This function is actually not technically sensible or wrong, because it can be moved at high loads of the hydro consumer a higher pilot pressure better, however a lower pilot pressure is better at low load would.

Aus DE 40 21 347 C2 ist eine hydraulische Steuervorrichtung mit wenigstens einem Lasthalteventil in einer Arbeitsleitung des Hydroverbrauchers bekannt, bei der in der von der anderen Arbeitsleitung zum Aufsteuerkolben geführten Steuerdruckleitung eine hydraulische Dämpfungsvorrichtung für Druckschwankungen im System vorgesehen ist, die aus einem in der Steuerdruckleitung angeordneten Drosseldurchgang, einer von der Steuerdruckleitung abzweigenden Ablaßleitung und einem weiteren Drosseldurchgang in der Ablaßleitung besteht. Mit dieser Dämpfungsvorrichtung wird aufgrund permanent über die Drosselanordnung abströmenden Druckmittels eine verbesserte Dämpfung erzielt. Obwohl der Druck auf den Aufsteuerkolben geringer ist als der in der anderen Arbeitsleitung erzeugte Aufsteuerdruck, ändert sich der Aufsteuerdruck indirekt proportional zum Lastdruck. Bei hohem Lastdruck ergibt sich ein geringer Aufsteuerdruck, während bei niedriger Last ein hoher Aufsteuerdruck erforderlich ist. Die Dämpfungsvorrichtung stellt zwar eine vorbestimmbare hydraulische Untersetzung zwischen dem Aufsteuerdruck in der anderen Arbeitsleitung und dem Druck auf den Aufsteuerkolben her, jedoch ohne die nachteilige Gesetzmäßigkeit: hoher Lastdruck, niedriger Aufsteuerdruck; niedriger Lastdruck, hoher Aufsteuerdruck, zu eliminieren.From DE 40 21 347 C2 is a hydraulic control device with at least one load holding valve in a working line of the hydro consumer, in which in the from the other Working line to the control piston led control pressure line a hydraulic damping device for pressure fluctuations is provided in the system, which consists of a in the control pressure line arranged throttle passage, one of the Control pressure line branching drain line and another Throttle passage in the drain line exists. With this Damping device is permanently due to the throttle arrangement outflowing pressure medium an improved damping achieved. Although the pressure on the control piston is less is than the control pressure generated in the other working line, the pilot pressure changes indirectly proportionally to load pressure. At high load pressure there is a lower one Opening pressure, while at low load a high one Control pressure is required. The damping device provides a predeterminable hydraulic reduction between the control pressure in the other working line and the pressure on the control piston, but without the disadvantage Lawfulness: high load pressure, low pilot pressure; low load pressure, high pilot pressure, to eliminate.

Bei einer aus DE 32 16 580 A1 bekannten hydraulischen Steuervorrichtung ist in der anderen Arbeitsleitung zusätzlich eine Verstelldrossel enthalten, die mit zunehmendem Lastdruck ihre Durchgangsgröße verkleinert. Auf diese Weise wird lastdruckabhängig die Bewegungsgeschwindigkeit des Hydroverbrauchers unter der Last gegenüber der am Wegeventil eingestellten Bewegungsgeschwindigkeit verringert. Es ergibt sich zum Aufsteuern des Lasthalteventils bei hohem Lastdruck ein niedriger Aufsteuerdruck, weil der Aufsteuerdruck mit dem am Aufsteuerkolben wirkenden Druck übereinstimmt. Ferner wird nach Bewegungsbeginn des Hydroverbrauchers bei hohem Lastdruck der Aufsteuerdruck gegenüber dem Aufsteuerdruck vor Bewegungsbeginn abgesenkt.In a hydraulic control device known from DE 32 16 580 A1 is an additional one in the other work management Variable throttle included, which with increasing load pressure Passage size reduced. In this way it becomes dependent on the load pressure the speed of movement of the hydro consumer under the load compared to the movement speed set on the directional control valve reduced. It results in taxation of the load holding valve at high load pressure a low one Pilot pressure, because the pilot pressure with that on the pilot piston acting pressure matches. Furthermore, after Start of movement of the hydro consumer at high load pressure Control pressure compared to the control pressure before the start of movement lowered.

DE 39 11 022 A1 betrifft eine hydraulische Steuervorrichtung für einen einseitig über ein 4/3-Wegeventil aus einer einzigen Arbeitsleitung gegen eine Last beaufschlagbaren Hebezylinder, mit einem lasthaltenden Sperrventil, das zum Senken der Last hydraulisch über ein Stellglied entsperrbar ist. Eine mit variablem Druck beaufschlagbare Steuerleitung ist an ein Stellglied zum Verstellen des Wegeventils zwischen einer Senkstellung, einer Absperrstellung und einer Hebestellung und auch an das Stellglied zum Entsperren des Sperrventils angeschlossen. In der zu einer Rückstellvorrichtung des Stellglieds des Sperrventils verlängerten Steuerleitung sind zwei Drosseln vorgesehen, zwischen denen eine Entlastungsleitung zum Wegesteuerventil abzweigt, die in der Senk- und in der Sperrstellung des Wegesteuerventils zum Tank entlastet ist. Auch bei Druckvariationen in der Steuerleitung wird das Sperrventil bei einem vorbestimmten Druckwert entsperrt, der sich nach der Beaufschlagungsfläche des Stellglieds und der Kraft der Schließfeder des Sperrventils richtet. Die Druckvariationen der Steuerleitung werden zum Verstellen des Wegesteuerventils gegen Federkraft zwischen dessen Schaltstellungen und zur Volumenstromregelung für den Hebezylinder eingesetzt.DE 39 11 022 A1 relates to a hydraulic control device for one-sided via a 4/3-way valve from a single Working line against a loadable lifting cylinder, with a load-holding shut-off valve that is used to lower the load can be unlocked hydraulically via an actuator. One with variable The pressurizable control line is connected to an actuator for adjusting the directional valve between a lower position, a shut-off position and a lifting position and also on the actuator for unlocking the check valve is connected. In to a reset device of the actuator of the check valve extended control line, two chokes are provided, between which a relief line to the directional control valve branches off in the lowering and in the locked position of the Directional control valve to the tank is relieved. Even with pressure variations in the control line, the check valve is at a predetermined Unlocked pressure value, which is after the pressurized area of the actuator and the force of the closing spring of the Check valve directed. The pressure variations of the control line are used to adjust the directional control valve against spring force between its switching positions and for volume flow control used for the lifting cylinder.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren der eingangs genannten Art sowie eine hydraulische Steuervorrichtung zur Durchführung des Verfahrens anzugeben, mit denen die vom Lasthalteventil gesteuerte Bewegung des Hydroverbrauchers unter Last unabhängig von der Größe der Last feinfühlig steuerbar ist.The invention has for its object a method of type mentioned and a hydraulic control device to carry out the procedure by which the Movement of the hydraulic consumer controlled by the load holding valve controllable under load regardless of the size of the load is.

Die gestellte Aufgabe wird erfindungsgemäß mit den Merkmalen des Patentanspruchs 1 und den Merkmalen des Patentanspruchs 7 gelöst.The object is achieved according to the invention with the features of claim 1 and the features of claim 7 solved.

Verfahrensgemäß wird durch die Einstellung des Aufsteuerdrucks direkt proportional zum Lastdruck erreicht, daß sich bei hoher Last ein hoher Aufsteuerdruck und bei niedriger Last ein niedriger Aufsteuerdruck ergibt. In jedem Fall ist die hydraulische Steuervorrichtung dann steif. Die Bewegung des Hydroverbrauchers läßt sich feinfühlig steuern, weil bei geringer Last der Hydroverbraucher mit niedrigem Aufsteuerdruck und bei großer Last mit hohem Aufsteuerdruck gesteuert wird. Speziell bei hoher Last läßt sich dann auch eine wirksame Dämpfung von Druckschwankungen im System erzielen, weil ein großes Steuerdruckmittelvolumen bewegt wird. Dabei wird eine lastdruckabhängige Verstellung einer hydraulischen Untersetzung zwischen dem Aufsteuerdruck in der anderen Arbeitsleitung und dem am Aufsteuerkolben wirksamen Druck vorgenommen. In der hydraulischen Steuervorrichtung wird über die Drosselanordnung und die Ablaßleitung in Abhängigkeit von der Höhe des Lastdrucks mehr oder weniger Druckmittel exakt gesteuert abgelassen. Dadurch ist es möglich, für einen hohen Lastdruck einen hohen Aufsteuerdruck einzusteuern, obwohl der am Aufsteuerkolben wirksame Druck nur gering sein darf, weil dann der Lastdruck ohnedies bereits einen Großteil der Federkraft auf das Schließelement überwindet. Für die feinfühlige Bewegungssteuerung des Hydroverbrauchers ist jedoch der in der anderen Arbeitsleitung eingesteuerte hohe Aufsteuerdruck vorteilhaft. Umgekehrt wird bei niedrigem Lastdruck der niedrige Aufsteuerdruck in der anderen Arbeitsleitung eine feinfühlige Bewegungssteuerung des Hydroverbrauchers über das Lasthalteventil ermöglichen.According to the procedure, the setting of the pilot pressure achieved directly proportional to the load pressure that at high load a high pilot pressure and at low Load results in a low pilot pressure. In any case the hydraulic control device then stiff. The movement of the hydro consumer can be controlled sensitively, because at low load of the hydraulic consumers with low pilot pressure and controlled at high load with high pilot pressure becomes. An effective one can then be used, especially at high loads Achieve damping of pressure fluctuations in the system because a large control pressure medium volume is moved. Doing so a load pressure-dependent adjustment of a hydraulic reduction between the control pressure in the other working line and the effective pressure on the control piston. In the hydraulic control device is over the throttle arrangement and the drain line depending on the level of the load pressure more or less pressure medium exactly controlled drained. This makes it possible for a high Load pressure to control a high pilot pressure, although the effective pressure on the control piston may only be low because then the load pressure already already has a large part of the spring force overcomes the closing element. For the sensitive Motion control of the hydro consumer is, however, the in the other working line brought high control pressure advantageous. Conversely, at low load pressure, the low one Control pressure in the other working line a sensitive Motion control of the hydro consumer via the Enable load holding valve.

Die Verfahrensvariante gemäß Anspruch 2 ist zweckmäßig, weil die Druckuntersetzung nur im Steuerkreis vorgenommen wird, so daß in der anderen Arbeitsleitung kein spürbarer Einfluß auf die am Wegeventil eingestellte Bewegungsgeschwindigkeit des Hydroverbrauchers eintritt.The method variant according to claim 2 is useful because the pressure reduction is only carried out in the control circuit, so that there is no noticeable influence on the other work management the movement speed of the Hydro consumer enters.

Besonders zweckmäßig ist es gemäß Anspruch 3, den Aufsteuerdruck in direkter Abhängigkeit vom Lastdruck kontinuierlich zu verstellen. Es wird auf diese Weise für jede Lastgröße ein optimaler Aufsteuerdruck ermöglicht.It is particularly useful according to claim 3, the opening pressure in direct dependence on the load pressure continuously to adjust. It will be one for each load size optimal pilot pressure enables.

Bei einer einfacheren Ausführungsvariante des Verfahrens reicht es gemäß Anspruch 4 aus, den Aufsteuerdruck abgestuft einzustellen, und zwar zweckmäßigerweise in wenigstens einer Stufe.In a simpler variant of the method it is sufficient according to claim 4, the control pressure graded adjust, expediently in at least one Step.

Bei der Vorgangsweise gemäß Anspruch 5 wird mit der Druckminderung der jeweils optimale Aufsteuerdruck eingestellt und bei hohem Lastdruck ein spürbares Steuerdruckmittelvolumen bewegt, was für eine effektive Dämpfung von Druckschwingungen im System vorteilhaft ist.In the procedure according to claim 5 is with the pressure reduction the optimal pilot pressure is set and a noticeable control pressure medium volume at high load pressure moves, what an effective damping of pressure vibrations is advantageous in the system.

Der bei der Verfahrensvariante gemäß Anspruch 6 angegebene Einstellbereich läßt nahezu alle in der Praxis auftretenden Einsatzbedingungen optimal beherrschen. Bei sehr niedrigem Lastdruck könnte die Druckminderung sogar auf den Faktor Null reduziert werden, so daß der volle Aufsteuerdruck am Aufsteuerkolben wirksam ist.The specified in the process variant according to claim 6 Setting range leaves almost all that occur in practice Master operating conditions optimally. At very low Load pressure could even reduce the pressure to a factor of zero be reduced so that the full pilot pressure on the pilot piston is effective.

Bei der Ausführungsform gemäß Anspruch 8 wird die jeweilige Verstelldrossel durch den Lastdruck, den dem Lastdruck proportionalen Druck oder durch ein vom Lastdruck abgeleitetes elektrisches Signal oder über eine mechanische Verstelleinrichtung feinfühlig verstellt, um unter Berücksichtigung des gerade am Aufsteuerkolben notwendigen Drucks in der anderen Arbeitsleitung den Aufsteuerdruck so einzustellen, daß dieser eine feinfühlige Bewegung des Hydroverbrauchers ermöglicht.In the embodiment according to claim 8, the respective Variable throttle through the load pressure, which is proportional to the load pressure Pressure or one derived from the load pressure electrical signal or via a mechanical adjustment device sensitively adjusted to take into account the just at the control piston necessary pressure in the other Working line adjust the pilot pressure so that this enables sensitive movement of the hydro consumer.

Bei der alternativen Ausführungsform gemäß Anspruch 9 wird der Aufsteuerdruck stufenartig verstellt, indem mit zunehmendem Lastdruck wenigstens ein weiterer Drosseldurchgang zugeschaltet wird.In the alternative embodiment according to claim 9 the pilot pressure is gradually adjusted by increasing Load pressure switched on at least one further throttle passage becomes.

Baulich einfach ist die Ausführungsform zur Zu- bzw. Abschaltung wenigstens eines weiteren Drosseldurchgangs gemäß Anspruch 10. Der zu- bzw. abschaltbare Drosseldurchgang wird in Abhängigkeit von der Höhe des Lastdruckes aktiviert oder deaktiviert. The embodiment for connection or disconnection is structurally simple at least one further throttle passage according to claim 10. The throttle passage can be switched on or off in Activated or deactivated depending on the level of the load pressure.

Die Verstelleinrichtung läßt sich bei der Ausführungsform gemäß Anspruch 11 auf hydraulischem, elektrischem oder mechanischem Weg betätigen. Auf hydraulischem Weg wird aus dem Lastdruck oder auch aus dem Aufsteuerdruck das jeweilige Verstellsignal abgeleitet. Auf elektrischem Weg wird, z.B. über eine Druckmeßvorrichtung oder einen Druckschalter, aus dem Lastdruck ein elektrisches Signal für die Verstelleinrichtung erzeugt, das die Einstellung der Drosselanordnung vornimmt. Auf mechanischem Weg könnte mit einem von Lastdruck oder auch dem Aufsteuerdruck betätigbarem Hebelmechanismus oder Getriebe die jeweilige Einstellung vorgenommen werden.The adjustment device can be in accordance with the embodiment Claim 11 on hydraulic, electrical or mechanical Press away. Hydraulically, the Load pressure or the respective adjustment signal from the pilot pressure derived. Electrically, e.g. about a pressure measuring device or a pressure switch from which Load pressure an electrical signal for the adjustment device generated that makes the adjustment of the throttle arrangement. Mechanically, one could use one of load pressure or else the lever mechanism or gear which can be actuated by the opening pressure the respective setting can be made.

Besonders vorteilhaft ist die Ausführungsform gemäß Anspruch 12. Die verstellbare Drosselanordnung führt zusammen mit der Ablaßleitung neben der Druckuntersetzung die zusätzliche Aufgabe einer Dämpfung von Druckschwingungen im System aus, weil mittels des über die Drosselanordnung geführten Steuerdruckmittelvolumens die Kuppen und Täler von Druckschwingungsamplituden gekappt und die Druckschwingungen somit rasch gedämpft werden. Da die hydraulische Untersetzung und die Dämpfung nur im Steuerkreis und mit dem Steuerdruckmittel durchgeführt werden, sind die damit verbundenen Verluste vernachlässigbar, insbesondere dann, wenn das abströmende Steuerdruckmittel in die gerade drucklose Arbeitsleitung zurückgeführt wird.The embodiment according to claim is particularly advantageous 12. The adjustable throttle arrangement leads together with the Drain line in addition to the pressure reduction the additional task damping of pressure vibrations in the system because by means of the control pressure medium volume guided via the throttle arrangement the peaks and valleys of pressure vibration amplitudes cut and the pressure fluctuations quickly be dampened. Because the hydraulic reduction and the Damping only in the control circuit and with the control pressure medium the associated losses are negligible, especially when the outgoing control pressure medium returned to the unpressurized working line becomes.

Grundsätzlich ist bei allen Ausführungsformen zu berücksichtigen, daß durch die Abstimmung der Beaufschlagungsfläche des Aufsteuerkolbens mit der Lastdruck-Beaufschlagungsfläche des Schließelements bereits ein Übersetzungsfaktor in die Steuervorrichtung integriert ist, um den Aufsteuerdruck in der anderen Arbeitsleitung in ein für die Steuerung günstiges Verhältnis zum Lastdruck zu bringen. Dieses Verhältnis wird auch bei der Erfindung mitberücksichtigt und dadurch gewinnbringend ergänzt, daß das Verhältnis zwischen dem Aufsteuerdruck und dem am Aufsteuerkolben wirkenden Druck noch zusätzlich lastdruckabhängig verstellt wird. Mit dieser sozusagen überlagerten hydraulischen Untersetzung zwischen dem Aufsteuerdruck und dem am Aufsteuerkolben wirkenden Druck ist es möglich, das Verhältnis zwischen der Beaufschlagungsfläche des Aufsteuerkolbens und der Beaufschlagungsfläche des Schließelementes sogar noch günstiger zu wählen.In principle, it must be taken into account in all embodiments that that by coordinating the surface area of the Control piston with the load pressure area of the Closing element already has a translation factor in the control device is integrated to the pilot pressure in the other Work management in a favorable ratio for the control to bring to the load pressure. This ratio will also taken into account in the invention and thereby profitable adds that the relationship between the opening pressure and the pressure acting on the control piston in addition is adjusted depending on the load pressure. Overlaid with this, so to speak hydraulic reduction between the pilot pressure and the pressure acting on the control piston, it is possible the ratio between the exposure area of the Control piston and the contact surface of the closing element to choose even cheaper.

Anhand der Zeichnung werden Ausführungsformen des Erfindungsgegenstandes erläutert. Es zeigen:

Fig. 1
ein Blockschaltbild einer hydraulischen Steuervorrichtung mit einer integrierten Schema-Schnittdarstellung eines Lasthalteventils,
Fig.2-6
Detailvariationen zu Fig. 1, und
Fig. 7
ein Diagramm.
Embodiments of the subject matter of the invention are explained with the aid of the drawing. Show it:
Fig. 1
1 shows a block diagram of a hydraulic control device with an integrated schematic sectional representation of a load holding valve,
Fig.2-6
Detailed variations to Fig. 1, and
Fig. 7
a diagram.

Eine hydraulische Steuervorrichtung S gemäß Fig. 1 dient zur Bewegungssteuerung eines Hydroverbrauchers Z, beispielsweise eines doppeltwirkenden Hydraulikzylinders mit Differentialkolben 1, dessen beide Beaufschlagungsräume mit 2 und 3 angedeutet sind. Der Hydroverbraucher Z wird beispielsweise durch eine Last L in der angegebenen Pfeilrichtung beaufschlagt, die im Raum 3 einen bestimmten Lastdruck LD hervorruft. Der Hydroverbraucher Z ist über Arbeitsleitungen 4 und 5 und ein Wegesteuerventil W wahlweise an eine Druckquelle P bzw. einen Rücklauf oder Tank T anschließbar.A hydraulic control device S according to FIG. 1 is used for Motion control of a hydro consumer Z, for example a double-acting hydraulic cylinder with differential piston 1, the two pressurized spaces indicated by 2 and 3 are. The hydro consumer Z is, for example, by a Load L is applied in the direction of the arrow indicated in the Room 3 causes a certain load pressure LD. The hydro consumer Z is via working lines 4 and 5 and a directional control valve W optionally to a pressure source P or a return or tank T can be connected.

In der einen Arbeitsleitung 5 ist ein hydraulisch aufsteuerbares Lasthalteventil H angeordnet, das eine ein Schließelement 7 in Schließrichtung auf einen Sitz 8 beaufschlagende, vorzugsweise einstellbare, Feder 6 sowie einen mit einem Druck P9 beaufschlagbaren Aufsteuerkolben 9 aufweist. Der Lastdruck LD wirkt entgegen der Kraft der Feder 6 im Sitz 8 auf das Schließelement 7. Bei Beaufschlagung wirkt der Aufsteuerkolben 9 ebenfalls entgegen der Kraft der Feder 6. Von der anderen Arbeitsleitung 4 zweigt im Punkt 10 eine Steuerdruckleitung 11 zum Aufsteuerkolben 9 ab, über die der in der anderen Arbeitsleitung 4 eingesteuerte Aufsteuerdruck AD zu dem Druck P9 umgesetzt wird, der dem Aufsteuerdruck AD entsprechen, aber auch wesentlich niedriger sein kann.In one working line 5 is a hydraulically openable Load holding valve H is arranged, which is a closing element 7 in the closing direction on a seat 8, preferably adjustable spring 6 as well as a pressure P9 Control piston 9 has. The load pressure LD acts against the force of the spring 6 in the seat 8 on the closing element 7. When applied, the control piston 9 acts also against the force of the spring 6. From the other work management 4 a control pressure line 11 branches at point 10 to the control piston 9, via which in the other working line 4 controlled control pressure AD converted to the pressure P9 that correspond to the opening pressure AD, but also can be much lower.

In der Steuerdruckleitung 11 ist eine hydraulische Dämpfungsvorrichtung D enthalten, mit der Druckschwingungen im System und für den Aufsteuerkolben 9 abdämpfbar sind. Teil der Dämpfungsvorrichtung D ist eine zweckmäßigerweise einstellbare Dämpfdrossel 12 mit in Aufsteuerrichtung des Aufsteuerkolbens 9 die Dämpfdrossel 12 umgehendem Rückschlagventil 13, die zwischen einer Abzweigung 14 einer Ablaßleitung 15 und dem Aufsteuerkolben 9 angeordnet sind.In the control pressure line 11 is a hydraulic damping device D included with the pressure vibrations in the system and can be damped for the control piston 9. Part of the damping device D is expediently adjustable Damping throttle 12 with in the opening direction of the opening piston 9 the damping throttle 12 immediate check valve 13 between a branch 14 of a drain line 15 and the control piston 9 are arranged.

Zwischen den Abzweigungen 10 und 14 ist ein Drosseldurchgang 16 (strichliert angedeutet als Verstelldrossel) angeordnet, der zusammen mit einem Ablaßdrosseldurchgang 17 (ebenfalls als Verstelldrossel strichliert angedeutet) in der Ablaßleitung 15 eine verstellbare Drosselanordnung A bildet, zu deren Verstellung eine Verstelleinrichtung C vorgesehen ist. Die Ablaßleitung 15 ist entweder an den Tank T angeschlossen oder an die eine Arbeitsleitung 5 (nicht gezeigt). Das Lasthalteventil H ist in Strömungsrichtung zum Hydroverbraucher Z durch eine Leitungsschleife 5a umgehbar, in der ein zum Hydroverbraucher Z öffnendes Rückschlagventil R angeordnet ist.Between the branches 10 and 14 is a throttle passage 16 (indicated by dashed lines as an adjusting throttle), the together with a discharge throttle passage 17 (also as a variable throttle indicated by dashed lines) in the drain line 15 a adjustable throttle arrangement A forms, for their adjustment an adjusting device C is provided. The drain line 15 is either connected to the tank T or to a working line 5 (not shown). The load holding valve H is in Flow direction to the hydro consumer Z through a line loop 5a can be bypassed, in which an opening to the hydro consumer Z Check valve R is arranged.

Die Verstelleinrichtung C ist über eine Pilotleitung 18 an die eine Arbeitsleitung 5 angeschlossen, so daß der Lastdruck im Raum 3 stets auch in der Verstelleinrichtung C zur Verfügung steht, um die verstellbare Drosselanordnung A in Abhängigkeit von der Höhe des Lastdrucks LD so zu verstellen, daß bei hohem Lastdruck mehr Druckmittel über die Ablaßleitung 15 abgelassen wird als bei niedrigem Lastdruck. Bei niedrigem Lastdruck könnte sogar die Ablaßdrossel 17 vollständig geschlossen werden. The adjustment device C is connected to the pilot line 18 a working line 5 connected so that the load pressure in Room 3 is always available in the adjustment device C. is dependent on the adjustable throttle arrangement A. to adjust the height of the load pressure LD so that at high Load pressure more pressure medium discharged via the drain line 15 is considered at low load pressure. At low load pressure even the discharge throttle 17 can be closed completely.

Alternativ wäre es möglich, die Verstelleinrichtung C auch an eine Pilotleitung 18' anzuschließen, in der der Aufsteuerdruck AD wirksam ist. Ferner könnte die Verstelleinrichtung C auch elektrisch betätigt werden, beispielsweise über einen elektrischen Druckmesser 22 (oder einen Druckschalter) für den Lastdruck, der über eine Signalleitung 23 mit der Verstelleinrichtung C verbunden ist. Auch eine mechanische Übertragung eines vom Lastdruck abhängigen Signals an die Verstelleinrichtung C wäre möglich.Alternatively, it would also be possible to adjust the adjustment device C to connect a pilot line 18 'in which the pilot pressure AD is effective. The adjusting device C could also are operated electrically, for example via an electric Pressure gauge 22 (or a pressure switch) for the Load pressure via a signal line 23 with the adjusting device C is connected. Even a mechanical transmission of a signal dependent on the load pressure to the adjusting device C would be possible.

In der gezeigten Stellung befindet sich die hydraulische Steuervorrichtung in der Neutralstellung. Der Hydroverbraucher Z steht. Der Lastdruck wird vom Lasthalteventil H und vom Rückschlagventil R aufgenommen. Wird das Wegesteuerventil W aus der gezeigten Neutralstellung nach links verstellt, dann werden die Druckquelle P mit der einen Arbeitsleitung 5 und die andere Arbeitsleitung 4 mit dem Tank T verbunden. Der Hydromotor Z wird über das öffnende Rückschlagventil R in Heberichtung bewegt. Die Bewegungsgeschwindigkeit richtet sich z.B. nach dem Ausmaß der Verstellung des Wegesteuerventils W. Das ausgeschobene Druckmittel aus dem Raum 2 wird über die andere Arbeitsleitung 4 zum Tank T geleitet. Der Aufsteuerkolben 9 bleibt ohne spürbare Beaufschlagung.The hydraulic control device is in the position shown in the neutral position. The hydro consumer Z stands. The load pressure is from the load holding valve H and from the check valve R added. If the directional control valve W from the shown neutral position to the left, then the Pressure source P with one working line 5 and the other working line 4 connected to the tank T. The hydraulic motor Z is moved in the lifting direction via the opening check valve R. The speed of movement is e.g. according to the extent the adjustment of the directional control valve W. The extended Pressure medium from room 2 is via the other working line 4 passed to the tank T. The control piston 9 remains without noticeable Impingement.

Wird das Wegesteuerventil W aus der gezeigten Neutralstellung nach rechts verstellt, dann werden die andere Arbeitsleitung 4 mit der Druckquelle P und die eine Arbeitsleitung 5 mit dem Tank verbunden. In der anderen Arbeitsleitung 4 wird am Punkt 10 ein Aufsteuerdruck AD aufgebaut, der auch im Raum 2 des Hydroverbrauchers Z wirkt. Über die Steuerdruckleitung 11 und die verstellbare Drosselanordnung A wird der Aufsteuerdruck AD auf den vom jeweiligen Lastdruck LD abhängigen Druck P9 gemindert, wobei die Verstelleinrichtung C lastdruckabhängig so betätigt wird, daß bei hohem Lastdruck ein hoher Aufsteuerdruck AD, hingegen bei niedrigem Lastdruck LD ein niedrigerer Aufsteuerdruck AD eingesteuert wird. Ist der für den jeweiligen Lastdruck vorherbestimmte Aufsteuerdruck AD erreicht, dann steuert der Aufsteuerkolben 9 das Lasthalteventil H auf, so daß das Druckmittel aus der einen Arbeitsleitung 5 abströmt und, z.B. die am Wegesteuerventil W, eingestellte Bewegungsgeschwindigkeit erreicht wird. Der Aufsteuerdruck AD wird vor Bewegungsbeginn des Hydromotors Z, d.h. vor dem Aufsteuern des Lasthalteventils H, eingestellt.The directional control valve W is from the neutral position shown adjusted to the right, then the other work line 4 with the pressure source P and the one working line 5 with the Tank connected. In the other working line 4 is at the point 10 a pilot pressure AD built up, which also in room 2 of the hydraulic consumer Z works. Via the control pressure line 11 and the adjustable throttle arrangement A, the pilot pressure AD the pressure P9 dependent on the respective load pressure LD is reduced, wherein the adjusting device C is operated depending on the load pressure is that, at high load pressure, a high pilot pressure AD, however at low load pressure LD, a lower pilot pressure AD is controlled. Is the one predetermined for the respective load pressure Control pressure AD reached, then the control piston controls 9, the load holding valve H, so that the pressure medium flows out of the one working line 5 and, e.g. the on Directional control valve W, set movement speed reached becomes. The pilot pressure AD is before the start of the movement Hydraulic motor Z, i.e. before opening the load holding valve H, set.

Aus dem Diagramm der Fig. 7 ist zu entnehmen, wie der Aufsteuerdruck AD im Verhältnis zum Lastdruck LD bei verschiedenen Lasten (vL) derart eingestellt wird, daß bei hohem Lastdruck LD ein hoher Aufsteuerdruck AD und bei jeweils kleinerem Lastdruck LD auch ein kleinerer Aufsteuerdruck eingestellt wird. Obwohl dies nicht dargestellt ist, könnte bei kleinem Lastdruck der Aufsteuerdruck sogar höher sein als der Lastdruck. Die Verstellung des Aufsteuerdrucks in Abhängigkeit vom jeweiligen Lastdruck wird zweckmäßigerweise kontinuierlich oder ggfs. stufenweise, d.h. in mindstens einer Stufe, vorgenommen. Die Fig. 2 bis 4 zeigen Ausführungsformen zur kontinuierlichen Veränderung des Aufsteuerdrucks. Die Ausführungsform der Fig. 5 und 6 ermöglichen hingegen eine stufenweise Veränderung des Aufsteuerdrucks.The diagram in FIG. 7 shows how the opening pressure AD in relation to the load pressure LD for different loads (vL) is set such that at high load pressure LD a high pilot pressure AD and a smaller load pressure LD also a smaller pilot pressure is set. Even though this is not shown, could at a low load pressure Opening pressure may even be higher than the load pressure. The adjustment the control pressure depending on the respective Load pressure is expediently continuously or, if necessary, gradually, i.e. in at least one stage. The Fig. 2-4 show embodiments for continuous change the control pressure. 5 and 6 allow, however, a gradual change in the pilot pressure.

In Fig. 2 ist der Drosseldurchgang 16 in der Steuerdruckleitung 11 mit fester Durchgangsgröße eingesetzt. Hingegen ist der Ablaßdrosseldurchgang 17' als Verstelldrossel ausgebildet, die sich aus der Pilotleitung 18 bzw. 18' mit zunehmendem Lastdruck in ihrer Durchgangsgröße vergrößern läßt. Bei niedrigem Lastdruck kann die Verstelldrossel 17' sogar vollständig geschlossen werden.2, the throttle passage 16 is in the control pressure line 11 used with a fixed passage size. In contrast, the discharge throttle passage 17 'formed as an adjustment throttle from the pilot line 18 or 18 'with increasing load pressure can increase in their passage size. At low The throttle 17 'can even be completely closed under load pressure become.

In Fig. 3 ist der Drosseldurchgang 16' in der Steuerdruckleitung 11 als Verstelldrossel 16' ausgebildet, die sich über die Pilotleitung 18 bzw. 18' derart verstellen läßt, daß mit zunehmendem Lastdruck die Durchgangsgröße verkleinert wird. Der Ablaßdrosseldurchgang 17 in der Ablaßleitung 15 ist hingegen mit unveränderlicher Durchgangsgröße angeordnet.In Fig. 3, the throttle passage 16 'is in the control pressure line 11 is designed as an adjusting throttle 16 ', which extends over the Pilot line 18 or 18 'can be adjusted such that with increasing Load pressure the passage size is reduced. The drain throttle passage 17 in the drain line 15, however, is with fixed passage size arranged.

In Fig. 4 sind die Drosseldurchgänge 16' und 17' als Verstelldrosseln ausgebildet und über die Pilotleitung 18 bzw. 18' gegensinnig verstellbar, d.h. die Verstelldrossel 16 wird mit zunehmendem Lastdruck in ihrer Durchgangsgröße verkleinert, hingegen die Verstelldrossel 17' mit zunehmendem Lastdruck in ihrer Durchgangsgröße vergrößert. Die jeweilige Verstelldrossel 17', 16' könnte auch durch ein elektrisches oder mechanisches Signal verstellt werden.4, the throttle passages 16 'and 17' are variable throttles trained and via the pilot line 18 or 18 ' adjustable in opposite directions, i.e. the adjusting throttle 16 is with increasing load pressure reduced in their passage size, however, the adjusting throttle 17 'with increasing load pressure in their passage size increased. The respective variable throttle 17 ', 16' could also be electrical or mechanical Signal can be adjusted.

Bei der Ausführungsform der Fig. 5 ist (beispielsweise) der Drosseldurchgang 16 in der Steuerdruckleitung 11 mit unveränderbarer Durchgangsgröße ausgebildet. In der Ablaßleitung 15 ist der Ablaßdrosseldurchgang 17 (beispielsweise) mit unveränderbarer Durchgangsgröße ausgebildet. Der Ablaßdrosseldurchgang 17 wird von einer Leitungsschleife 19 in der Ablaßleitung 15 umgangen, in der ein Ventil 20, z.B. ein in Abströmrichtung öffnendes Rückschlagventil, sowie diesem nachgeordnet ein weiterer Drosseldurchgang 17" vorgesehen sind. Als Verstelleinrichtung C für die Drosselanordnung A ist ein Sperrelement 21 vorgesehen, das an die Pilotleitung 18 bzw. 18' angeschlossen ist und bei höherem Lastdruck das Ventil 20 entsperrt, so daß der weitere Drosseldurchgang 17" zugeschaltet wird. Es wäre auch denkbar, die Verstelleinrichtung C mittels eines elektrischen Signals oder auf mechanischem Weg (bei 24 angedeutet) entsprechend zu verstellen. Ferner könnten mehrere zusätzliche und wahlweise zu- bzw. abschaltbare Ablaßdrosseldurchgänge 17" vorgesehen sein. Zusätzlich wäre es möglich, auch die Drosseldurchgänge 16 bzw. 17 als Verstelldrosseln entsprechend den Fig. 2 bis 4 auszubilden und zu verstellen. (Drosselkombination mit Verstelldrosseln und festen Drosseln).5 is (for example) the Throttle passage 16 in the control pressure line 11 with unchangeable Passage size trained. In the drain line 15 is the discharge throttle passage 17 (for example) with unchangeable Passage size trained. The drain throttle passage 17 is a line loop 19 in the drain line 15th bypassed in which a valve 20, e.g. one in the outflow direction opening check valve, and another downstream Throttle passage 17 "are provided. As an adjusting device C for the throttle arrangement A is a blocking element 21 provided that connected to the pilot line 18 or 18 ' is and at higher load pressure, the valve 20 unlocked, so that the further throttle passage 17 "is switched on. It would be also conceivable, the adjusting device C by means of an electrical Signal or by mechanical means (indicated at 24) to adjust accordingly. There could also be several additional ones and optional cut-off throttle passages 17 " be provided. In addition, it would also be possible to use the throttle passages 16 or 17 as variable chokes according to the Fig. 2 to 4 to train and adjust. (Restrictor combination with variable throttles and fixed throttles).

Bei der Ausführungsform der Fig. 6, die in der Funktion der Ausführungsform der Fig. 5 entspricht, wird die Sperreinrichtung 21' durch ein elektrisches Signal in der Leitung 23 (s. Fig.1) unter Hilfe eines Schaltmagneten 25 betätigt, um das Ventil 20 bei hohem Lastdruck zu öffnen und bei niedrigem Lastdruck zu sperren. Analog zu Fig. 5 könnten auch in Fig. 6 mehrere zusätzliche Ablaßdrosseldurchgänge 17" vorgesehen sein. In den Fig. 5 und 6 kann der Drosseldurchgang 16 einen Durchmesser von 0,5 mm und jeder Drosseldurchgang 17, 17" einen Durchmesser von 0,4 mm haben.In the embodiment of Fig. 6, which in the function of 5 corresponds to the locking device 21 'by an electrical signal in line 23 (s. Fig.1) actuated with the help of a switching magnet 25 to the Open valve 20 at high load pressure and at low Lock load pressure. Analogously to FIG. 5, FIG. 6 could also several additional drain throttle passages 17 "may be provided. 5 and 6, the throttle passage 16 can have a diameter of 0.5 mm and each throttle passage 17, 17 "one Have a diameter of 0.4 mm.

Claims (12)

  1. Method for controlling a hydraulic consumer (Z), in particular a hydraulic cylinder capable of being acted upon on two sides and having a differential piston (1), which hydraulic consumer is connected to two working lines and in at least one working line (5) of which is arranged a hydraulically openable load-holding valve (H) which has a spring-loaded closing element (7), acted upon in the opening direction by the respective load pressure of the hydraulic consumer, and, for the closing element (7), an opening piston (9) which is capable of being acted upon by pressure counter to the spring load (6) and the action pressure (P9) of which is derived from an opening pressure (AD) in the other working line (4), characterized in that, before the commencement of the opening of the load-holding valve (H), the ratio between the load pressure (LD) and the opening pressure (AD) is set in proportion to the load pressure (LD) in such a way that a high opening pressure (AD) is obtained in the case of a high load pressure (LD), whereas a low opening pressure (AD) is obtained in the case of a low load pressure (LD).
  2. Method according to Claim 1, characterized in that, to set the ratio between the load pressure (LD) and the opening pressure (AD), the action pressure (P9) on the opening piston (9) is reduced in relation to the opening pressure (AD) prevailing in the other working line (4).
  3. Method according to Claim 1, characterized in that the respective pressure ratio (LD:AD) is adjusted continuously.
  4. Method according to Claim 1, characterized in that the respective pressure ratio (LD:AD) is adjusted in steps.
  5. Method according to at least one of Claims 1 to 4, characterized in that the respective pressure ratio (LD:AD) is set by means of a discharge line (15) and a throttle arrangement (A) adjustable as a function of load pressure, in that, with a higher load pressure (LD), relatively more control pressure medium is discharged.
  6. Method according to at least one of Claims 1 to 5, characterized in that the respective pressure ratio (LD:AD) is set at between 10:1 and 1:1, preferably at between 8.5:1 and 2.5:1.
  7. Hydraulic control device, in particular for carrying out the method according to Claim 1, for a hydraulic consumer (Z), in particular a hydraulic cylinder capable of being acted upon on two sides and having a differential piston, which hydraulic consumer is connected to two working lines selectively connectable to a pressure source (P) or to a return (T) via a directional control valve (W) and in at least one working line (5) of which is arranged a load-holding valve (H) which can be opened hydraulically from the other working line (4) and which has a spring-loaded closing element (7), acted upon in the opening direction by the load pressure in the hydraulic consumer counter to the spring load (6), and, for the closing element, an opening piston (9) which is likewise capable of being acted upon counter to the spring load (6) by a pressure (P9) which can be derived via a control-pressure line (11) from the opening pressure fed in the other working line (4), characterized in that at least one discharge line (15) is connected to the control-pressure line (11) between the other working line (4) and the opening piston (9), in that a throttle element (16; 16') is arranged between the other working line (4) and the branch (14) of the discharge line (15) and at least one discharge throttle element (17; 17'; 17'') is arranged in the discharge line (15), said throttle element and said discharge throttle element co-operating with one another and being designed as an adjustable throttle arrangement (A), and in that there is provided for the throttle arrangement (A) an adjusting means (C) which can be actuated as a function of load pressure and by which, with an increasing load pressure (LD), the passage size of the discharge throttle passage (17'; 17; 17'') can be enlarged and/or the passage size of the throttle passage (16'; 16) can be reduced.
  8. Hydraulic control device according to Claim 7, characterized in that the throttle element (16') and/or the discharge throttle element (17') are/is designed as an adjusting throttle/adjusting throttles, and in that the adjusting means (C) of the respective adjusting throttle (16', 17') is connected to a pilot line (18, 18') providing the load pressure (LD) or a pressure proportional to the load pressure (LD), for example the opening pressure (AD) in the other working line (4).
  9. Hydraulic control device according to Claim 8, characterized in that the discharge throttle element has a plurality of parallel throttle passages (17, 17''), and in that at least one of the throttle passages can be cut in or cut off by the adjusting means (C).
  10. Hydraulic control device according to Claim 9, characterized in that at least one throttle passage (17'') of the discharge throttle element is assigned a valve (20), preferably a non-return valve; opening in the outflow direction, and in that a shut-off element (21) capable of being actuated as a function of load pressure is provided as adjusting means (C) for the valve (20).
  11. Hydraulic control device according to at least one of Claims 7 to 10, characterized in that the adjusting means (C) can be actuated as a function of load pressure hydraulically, electrically or mechanically.
  12. Hydraulic control device according to one of Claims 7 to 11, characterized in that the adjustable throttle arrangement (A) at the same time forms, with the discharge line (15), a pressure-vibration damping device (D) for the opening piston (9).
EP96111864A 1995-08-07 1996-07-23 Method to control a hydraulic actuator and hydraulic control system for carrying out said method Expired - Lifetime EP0758056B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19528981 1995-08-07
DE19528981A DE19528981C1 (en) 1995-08-07 1995-08-07 Method for controlling double-sided activatable hydraulic cylinder with differential piston connected to two work conduits

Publications (3)

Publication Number Publication Date
EP0758056A2 EP0758056A2 (en) 1997-02-12
EP0758056A3 EP0758056A3 (en) 1999-08-18
EP0758056B1 true EP0758056B1 (en) 2002-12-18

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EP96111864A Expired - Lifetime EP0758056B1 (en) 1995-08-07 1996-07-23 Method to control a hydraulic actuator and hydraulic control system for carrying out said method

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EP (1) EP0758056B1 (en)
AT (1) ATE230071T1 (en)
DE (2) DE19528981C1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19745489B4 (en) * 1997-10-15 2004-07-22 O & K Orenstein & Koppel Aktiengesellschaft System for load-pressure-independent control and load holding of several rotary and / or translatory consumers
DE102004017786B4 (en) * 2004-04-02 2007-05-24 Schunk Gmbh & Co. Kg Spann- Und Greiftechnik Adapter device for a fluidic working means of a machine tool

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2559029C2 (en) * 1975-12-29 1985-10-31 Heilmeier & Weinlein Fabrik für Oel-Hydraulik GmbH & Co KG, 8000 München Brake valve
US4244275A (en) * 1979-01-15 1981-01-13 Abex Corporation Counterbalance valve
DE2946765C2 (en) * 1979-11-20 1986-04-30 Thyssen Industrie Ag, 4300 Essen Releasable check valve
DE3216580A1 (en) * 1981-05-07 1983-02-24 Hiab-Foco AB, 82401 Hudiksvall Load-holding and load-lowering brake valve
DE3201546C2 (en) * 1982-01-20 1986-03-27 Mannesmann Rexroth GmbH, 8770 Lohr Device for controlling a hydraulic motor
DE3911022A1 (en) * 1987-10-05 1990-10-11 Rexroth Mannesmann Gmbh Control circuit for a hydraulic power lift operated with a variable-displacement pump
JPH01133503U (en) * 1988-03-03 1989-09-12
DE3929466A1 (en) * 1989-09-05 1991-03-21 Rexroth Mannesmann Gmbh CONTROL CIRCUIT FOR A HYDRAULIC POWER LIFT OPERATED WITH A PUMP
DE4021347A1 (en) * 1990-07-05 1992-01-16 Heilmeier & Weinlein HYDRAULIC CONTROL DEVICE

Also Published As

Publication number Publication date
EP0758056A2 (en) 1997-02-12
DE19528981C1 (en) 1996-10-02
DE59609991D1 (en) 2003-01-30
ATE230071T1 (en) 2003-01-15
EP0758056A3 (en) 1999-08-18

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