EP0856107B1 - Output regulation with load sensing - Google Patents

Output regulation with load sensing

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Publication number
EP0856107B1
EP0856107B1 EP96934569A EP96934569A EP0856107B1 EP 0856107 B1 EP0856107 B1 EP 0856107B1 EP 96934569 A EP96934569 A EP 96934569A EP 96934569 A EP96934569 A EP 96934569A EP 0856107 B1 EP0856107 B1 EP 0856107B1
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EP
European Patent Office
Prior art keywords
pressure
setting
counter
control unit
electronic control
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
EP96934569A
Other languages
German (de)
French (fr)
Other versions
EP0856107A1 (en
Inventor
Mikko Erkkilae
Karl-Heinz Vogl
Bernd Obertrifter
Felix Zu Hohenlohe
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.)
Brueninghaus Hydromatik GmbH
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Brueninghaus Hydromatik GmbH
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Publication of EP0856107A1 publication Critical patent/EP0856107A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06—Control using electricity
    • F04B49/065—Control using electricity and making use of computers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/05—Pressure after the pump outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/06—Pressure in a (hydraulic) circuit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/09—Flow through the pump

Definitions

  • the present invention relates to a device for controlling the power of at least one driven by a motor, promoting in a work line Variable pump according to the preamble of claim 1 or to a method for Regulation of the power from a motor driven into a work line promoting variable displacement pump according to the preamble of claim 6.
  • a device for power control is shown as from the generic DE-PS 44 05 234 is known.
  • hydrostatic variable pumps 1 and 2 such as axial piston pumps in Swashplate construction, are via a working line 3 to one each, not shown Consumers, such as the chassis and slewing motor of an excavator, as well connected via a suction line 4 to a tank 5.
  • Both variable pumps 1, 2 are by a common drive motor 6, such as one Internal combustion engine, driven and rotating at the same speed.
  • To adjust your Funding volume is one actuator each, consisting of two single-acting hydraulic actuating cylinders 7, 8 provided.
  • an actuating piston 9 is slidably arranged and via a Piston rod 10 with an actuator 11, 12 of the respective variable pump 1 or 2 coupled.
  • Each actuating piston 9 delimits with its larger piston rod 10 facing piston surface in the respective actuating cylinder 7 and 8 a pressure chamber 13.
  • Die Pressure chambers 13 of the actuating cylinder 7 are each via an actuating pressure line 14 to the respective variable pump 1 or 2 assigned work line 3 connected.
  • Each of these working lines 3 leads to a pressure line 15 to the pressure chambers 13 of the Actuating cylinder 8, in each of which a compression spring 16 is arranged, which if necessary supported by the respective pressure line 15 from the respective Working line 3 removed working pressure, via the piston 9, the piston rod 10 and the actuator 12 the swash plate of the variable displacement pump 1 or 2 in the direction maximum funding volume.
  • Piston areas of the actuating pistons 9 in the actuating cylinders 7 are larger than those in FIG the actuating cylinders 8 arranged actuating piston 9, so that working pressure, which during the operation of the variable pumps 1, 2 via the signal pressure lines 14 in the Pressure chambers 13 of the actuating cylinder 7 builds up as actuating pressure, via the piston 9 and the Piston rod 10 the swash plate of the respective variable displacement pump 1, 2 in the direction minimum delivery volume adjusted.
  • One adjustable stop 17 each Pressure chambers 13 of the actuating cylinder 7 serves to achieve the maximum delivery volume Limit variable pumps 1, 2 to different values.
  • One control valve 18 each is arranged in the signal pressure lines 14 and divides them into each one leading to the respective working line 3 or to the respective actuating cylinder 7 Signal pressure line section 19, 20.
  • Each control valve 18 is a continuously adjustable one 3/2-way valve and has two working connections to the Signal pressure line sections 19 and 20 as well as a working connection to a tank 5 leading relief line 21 into which a leak oil line 22 of the respective Variable pump 1 or 2 opens. In the starting position shown in Figure 1 the working connection to the signal pressure line section 19 is blocked while the remaining work connections are open. From each signal pressure line section 19 leads a control pressure line 23 to a control connection of the associated Control valve 18 and enables its adjustment in the direction of an end position in which the working connections to the signal pressure line section 20 and the relief line 21 open and the remaining work connection is blocked.
  • the device for total power control of the two variable pumps 1, 2 comprises two electrical control elements 24, two transducers 25, one electronic Control unit 26 and a setpoint adjustment device 27 associated therewith.
  • the electrical control elements 24 are as force-controlled proportional magnets trained and one of the control valves 18 for the purpose of generating a control pressure counteracting back pressure assigned. They are each via a control signal line 28 connected to the electronic control unit 26.
  • the transducers 25 are designed as Hall angle sensors, which are used to detect the set delivery volume of the variable displacement pumps 1, 2 of the piston rod 10 of the assigned to the respective actuating cylinder 7 and via a signal line 29 to each electronic control unit 26 are connected.
  • the electronic control unit 26 is designed as a microcomputer, in the The characteristic curve KLg shown in FIG. 4 is stored in the memory part.
  • This characteristic represents the working pressure p as a function of the delivery volume V of a variable displacement pump, it is below due to its for torque or power control typical course referred to as the torque characteristic.
  • the torque characteristic In the present Embodiment are both variable pumps 1, 2 and thus theirs Torque characteristics identical, so that only one of these characteristics in Memory part of the microcomputer 26 is stored.
  • the area pxV under the torque characteristic curve KL g is constant for each delivery volume V or for each working pressure p and in the present exemplary embodiment is equal to the total drive torque of the drive motor 6.
  • the point P on the torque characteristic curve KL g denotes the transition from the so-called approach range ( vertical section of KL g ) to the control range (hyperbolic section of KL g ), and its ordinate value corresponds to the target value of the back pressure at the control valve 18, which is assigned to the variable pump 1 or 2, which transmits or is to transmit the total drive torque.
  • the ordinate value of point P thus also corresponds to the maximum torque that this variable displacement pump can transmit, that is to say in the present case the total drive torque of drive motor 6.
  • the setpoint value of the counterpressure at the control valve assigned to the other variable displacement pump is set to zero in order to prevent that this variable pump overloads the drive motor 6 by driving the consumer connected to it.
  • the setpoint sum of these two counterpressure setpoints and thus the sum of the Torques of both variable pumps 1, 2, which are not greater than the total drive torque of the drive motor 6 may also be in the memory part of the microcomputer 26 stored and can be set to any desired values using the setpoint adjustment device Size.
  • the object of the present invention is therefore to include vibrations in control loops Variable pumps, especially in so-called load-sensing control systems, on simple Way to decrease.
  • a device according to the preamble of claim 1 provided that also has a pressure relief valve through which the maximum Back pressure in the control valve is adjustable.
  • An electronic control unit controls this Pressure relief valve depending on the detected position signal.
  • the electronic control unit can produce characteristic curves - working pressure p as a function of Flow rate Q- constant pump output and the associated, in the control valve calculate the acting back pressure. One corresponding to a desired pump output Characteristic curve can be selected.
  • a speed sensor can advantageously be provided, by means of which the speed of the the variable pump driving motor can be detected and if the value falls below one a predetermined limit speed, a characteristic curve can be selected that a lower Pump output than that of the previously selected characteristic curve.
  • the pressure relief valve can be designed so that in the event of a failure electronic control unit the greatest possible back pressure in the control valve becomes.
  • Eirre adaptive adjustment of the control parameters in the electronic control unit can enabled by a device for detecting the temperature of the hydraulic oil become.
  • one of the electronic control unit Position signal dependent control signal is generated.
  • the control signal is one Pressure relief valve supplied. Due to the pressure relief valve, the maximum Back pressure set in the control valve.
  • Characteristic curves - working pressure p become dependent in the electronic control unit of the flow rate Q - constant pump output and the associated, in the control valve acting back pressure calculated. One corresponding to a desired pump output Characteristic curve is then selected.
  • a speed sensor detects the speed of the motor driving the variable pump and If the speed falls below a predetermined limit, a characteristic curve is selected which a lower pump output than that of the previously selected characteristic curve.
  • the maximum back pressure in the control valve is chosen so that the time Change in back pressure while the control valve is moving does not exceed a predetermined rate of change.
  • the maximum back pressure in the control valve can be chosen so that the time Change in the performance of the variable pump does not change a predetermined rate exceeds.
  • the temperature of the hydraulic oil can be recorded and the control parameters in the electronic control unit are adapted adaptively accordingly.
  • the position of the actuating device is determined based on the position signal via a predetermined period and the control parameters are dependent on the Recording changed.
  • Figure 1 shows a motor 6 which drives a variable displacement pump 1.
  • the invention is of course also applicable to hydraulic systems in which several Variable displacement pumps are driven by a motor, as referring to FIG. 2 was explained.
  • the system shown in Figure 1 thus represents any combinable universal unit.
  • the pump control valve 18 is in one so-called load-sensing system used. It has the task of To keep the pressure difference across a directional valve 46 in front of a consumer 3 constant, to improve the efficiency of the hydraulics. If there are several consumers, the The highest load pressure is taken into account and the pressure of the variable pump 1 is adapted to this.
  • the Load sensing control works as follows: If the consumer pressure in line 45 increases, this causes the main piston of the control valve 18 to be shifted to the left. A connection is thus established between the lines 23 and 20, which is a Increases the signal pressure of the actuating device 7 and thus swings out Variable pump 1. Thus, an increase in consumer pressure45 also causes System pressure upstream of consumer directional control valve 46.
  • FIG. 1 shows a unit in which a motor 6 drives only one pump 1. How the principle of the invention can be indicated by the reference symbol however, easily on systems with several variable pumps driven by one motor apply, for example in the case of a total power control, such as from the DE-PS 44 05 234 is known.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

A device is disclosed for regulating the output of at least one variable displacement pump (1) driven by a motor (6) and forcing a medium into a working line. This is done by altering the displaced volume of the pump by means of an adjusting device (7) to which an adjusting pressure (20) can be applied and which is biased in the direction of maximum displaced volume. The proposed device has a control valve (18) allocated to the adjusting device (7). The control valve can be subjected to a counter-pressure corresponding to the operating pressure in the operating line, the control valve (18) responding when the control pressure exceeds the counter-pressure, and the adjusting device (7) is acted on by the adjusting pressure to effect a reduction in the displaced volume of the variable displacement pump (1) in such a way that the product of operating pressure and displacement volume is constant. A device (25) is provided to determine the position of the adjusting device (7) and send a position signal proportional to that position to an electronic control unit (40). Also provided is a pressure limiting valve (42) by which the maximum counter-pressure in the control valve (18) can be set. The electronic control unit (40) controls the pressure limiting valve (42) in accordance with the position signal from the position sensor (25). Also disclosed is a method of controlling the output of a variable displacement pump (1) driven by a motor (6) and forcing a medium into an operating line.

Description

Die vorliegende Erfindung bezieht sich auf eine Vorrichtung zur Leistungsregelung von wenigstens einer von einem Motor angetriebenen, in eine Arbeitsleitung fördernden Verstellpumpe gemäß dem Oberbegriff des Anspruches 1 bzw. auf ein Verfahren zur Regelung der Leistung von einer von einem Motor angetriebenen, in eine Arbeitsleitung fördernden Verstellpumpe gemäß dem Oberbegriff des Anspruches 6.The present invention relates to a device for controlling the power of at least one driven by a motor, promoting in a work line Variable pump according to the preamble of claim 1 or to a method for Regulation of the power from a motor driven into a work line promoting variable displacement pump according to the preamble of claim 6.

In Figur 2 ist eine Vorrichtung zur Leistungsregelung dargestellt, wie sie aus der gattungsbildenden DE-PS 44 05 234 bekannt ist. Die in Figur 2 dargestellten hydrostatischen Verstellpumpen 1 und 2, wie zum Beispiel Axialkolbenpumpen in Schrägscheibenbauweise, sind über je eine Arbeitsleitung 3 an je einen nicht dargestellten Verbraucher, wie etwa das Fahrwerk und den Schwenkwerksmotor eines Baggers, sowie über je eine Ansaugleitung 4 an einen Tank 5 angeschlossen. Beide Verstellpumpen 1, 2 sind durch einen gemeinsamen Antriebsmotor 6, wie beispielsweise einen Brennkraftmotor, angetrieben und drehen mit gleicher Drehzahl. Zur Verstellung ihres Fördervolumens ist je eine Stelleinrichtung, bestehend aus je zwei einfachwirkenden hydraulischen Stellzylindern 7, 8 vorgesehen.In Figure 2, a device for power control is shown as from the generic DE-PS 44 05 234 is known. The shown in Figure 2 hydrostatic variable pumps 1 and 2, such as axial piston pumps in Swashplate construction, are via a working line 3 to one each, not shown Consumers, such as the chassis and slewing motor of an excavator, as well connected via a suction line 4 to a tank 5. Both variable pumps 1, 2 are by a common drive motor 6, such as one Internal combustion engine, driven and rotating at the same speed. To adjust your Funding volume is one actuator each, consisting of two single-acting hydraulic actuating cylinders 7, 8 provided.

In jedem Stellzylinder 7, 8 ist ein Stellkolben 9 verschiebbar angeordnet und über eine Kolbenstange 10 mit einem Stellglied 11, 12 der jeweiligen Verstellpumpe 1 bzw. 2 gekoppelt. Jeder Stellkolben 9 begrenzt mit seiner größeren, der Kolbenstange 10 abgewandten Kolbenfläche im jeweiligen Stellzylinder 7 bzw. 8 einen Druckraum 13. Die Druckräume 13 der Stellzylinder 7 sind über je eine Stelldruckleitung 14 an die der jeweiligen Verstellpumpe 1 bzw. 2 zugeordnete Arbeitsleitung 3 angeschlossen. Von diesen Arbeitsleitungen 3 führt je eine Druckleitung 15 zu den Druckräumen 13 der Stellzylinder 8, in denen je eine Druckfeder 16 angeordnet ist, die gegebenenfalls unterstützt durch den über die jeweilige Druckleitung 15 von der jeweiligen Arbeitsleitung 3 abgenommenen Arbeitsdruck, über den Kolben 9, die Kolbenstange 10 und das Stellglied 12 die Schrägscheibe der Verstellpumpe 1 bzw.2 in Richtung maximalen Fördervolumens beaufschlagt. Die den Kolbenstangen 10 abgewandten Kolbenflächen der Stellkolben 9 in den Stellzylindern 7 sind größer als diejenigen der in den Stellzylindern 8 angeordneten Stellkolben 9, so daß Arbeitsdruck, der sich während des Betriebs der Verstellpumpen 1, 2 iiber die Stelldruckleitungen 14 in den Druckräumen 13 der Stellzylinder 7 als Stelldruck aufbaut, über den Kolben 9 und die Kolbenstange 10 die Schrägscheibe der jeweiligen Verstellpumpe 1, 2 in Richtung minimalen Fördervolumens verstellt. Je ein verstellbarer Anschlag 17 in den Druckräumen 13 der Stellzylinder 7 dient dazu, das maximale Fördervolumen der Verstellpumpen 1, 2 auf unterschiedliche Werte zu begrenzen.In each actuating cylinder 7, 8, an actuating piston 9 is slidably arranged and via a Piston rod 10 with an actuator 11, 12 of the respective variable pump 1 or 2 coupled. Each actuating piston 9 delimits with its larger piston rod 10 facing piston surface in the respective actuating cylinder 7 and 8 a pressure chamber 13. Die Pressure chambers 13 of the actuating cylinder 7 are each via an actuating pressure line 14 to the respective variable pump 1 or 2 assigned work line 3 connected. From Each of these working lines 3 leads to a pressure line 15 to the pressure chambers 13 of the Actuating cylinder 8, in each of which a compression spring 16 is arranged, which if necessary supported by the respective pressure line 15 from the respective Working line 3 removed working pressure, via the piston 9, the piston rod 10 and the actuator 12 the swash plate of the variable displacement pump 1 or 2 in the direction maximum funding volume. The facing away from the piston rods 10 Piston areas of the actuating pistons 9 in the actuating cylinders 7 are larger than those in FIG the actuating cylinders 8 arranged actuating piston 9, so that working pressure, which during the operation of the variable pumps 1, 2 via the signal pressure lines 14 in the Pressure chambers 13 of the actuating cylinder 7 builds up as actuating pressure, via the piston 9 and the Piston rod 10 the swash plate of the respective variable displacement pump 1, 2 in the direction minimum delivery volume adjusted. One adjustable stop 17 each Pressure chambers 13 of the actuating cylinder 7 serves to achieve the maximum delivery volume Limit variable pumps 1, 2 to different values.

Je ein Regelventil 18 ist in den Stelldruckleitungen 14 angeordnet und teilt diese in je einen zur jeweiligen Arbeitsleitung 3 bzw. zum jeweiligen Stellzylinder 7 führenden Stelldruckleitungsabschnitt 19, 20 auf. Jedes Regelventil 18 ist ein als stetig verstellbares 3/2-Wegeventil ausgebildet und weist zwei Arbeitsanschlüsse an die Stelldruckleitungsabschnitte 19 bzw. 20 sowie einen Arbeitsanschluß an eine zum Tank 5 führenden Entlastungsleitung 21 auf, in die eine Leckölleitung 22 der jeweiligen Verstellpumpe 1 bzw. 2 einmündet. In der in der Figur 1 gezeigten Ausgangsstellung ist der Arbeitsanschluß an den Stelldruckleitungsabschnitt 19 gesperrt, während die verbleibenden Arbeitsanschlüsse offen sind. Von jedem Stelldruckleitungsabschnitt 19 führt eine Steuerdruckleitung 23 zu einem Steueranschluß des zugeordneten Regelventils 18 und ermöglicht dessen Verstellung in Richtung einer Endstellung, in der die Arbeitsanschlüsse an den Stelldruckleitungsabschnitt 20 und die Entlastungsleitung 21 offen und der verbleibende Arbeitsanschluß gesperrt ist.One control valve 18 each is arranged in the signal pressure lines 14 and divides them into each one leading to the respective working line 3 or to the respective actuating cylinder 7 Signal pressure line section 19, 20. Each control valve 18 is a continuously adjustable one 3/2-way valve and has two working connections to the Signal pressure line sections 19 and 20 as well as a working connection to a tank 5 leading relief line 21 into which a leak oil line 22 of the respective Variable pump 1 or 2 opens. In the starting position shown in Figure 1 the working connection to the signal pressure line section 19 is blocked while the remaining work connections are open. From each signal pressure line section 19 leads a control pressure line 23 to a control connection of the associated Control valve 18 and enables its adjustment in the direction of an end position in which the working connections to the signal pressure line section 20 and the relief line 21 open and the remaining work connection is blocked.

Die Vorrichtung zur Summenleistungsregelung der beiden Verstellpumpen 1, 2 umfaßt zwei elektrische Ansteuerelemente 24, zwei Meßwertgeber 25, eine elektronische Steuereinheit 26 und eine diesem zugeordnete Sollwert-Einstelleinrichtung 27.The device for total power control of the two variable pumps 1, 2 comprises two electrical control elements 24, two transducers 25, one electronic Control unit 26 and a setpoint adjustment device 27 associated therewith.

Die elektrischen Ansteuerelemente 24 sind als kraftgeregelte Proportionalmagnete ausgebildet und je einem der Regelventile 18 zwecks Erzeugung eines dem Steuerdruck entgegenwirkenden Gegendrucks zugeordnet. Sie sind über je eine Steuersignalleitung 28 mit der elektronischen Steuereinheit 26 verbunden.The electrical control elements 24 are as force-controlled proportional magnets trained and one of the control valves 18 for the purpose of generating a control pressure counteracting back pressure assigned. They are each via a control signal line 28 connected to the electronic control unit 26.

Die Meßwertgeber 25 sind als Hall-Winkelsensor ausgebildet, die zwecks Erfassung des jeweils eingestellten Fördervolumens der Verstellpumpen 1, 2 der Kolbenstange 10 des jeweiligen Stellzylinders 7 zugeordnet und über je eine Signalleitung 29 an die elektronische Steuereinheit 26 angeschlossen sind.The transducers 25 are designed as Hall angle sensors, which are used to detect the set delivery volume of the variable displacement pumps 1, 2 of the piston rod 10 of the assigned to the respective actuating cylinder 7 and via a signal line 29 to each electronic control unit 26 are connected.

Die elektronische Steuereinheit 26 ist als Mikrocomputer ausgebildet, in dessen Speicherteil die in Figur 4 gezeigte Kennlinie KLg gespeichert ist. Obwohl diese Kennlinie den Arbeitsdruck p in Abhängigkeit vom Fördervolumen V einer Verstellpumpe darstellt, ist sie nachstehend aufgrund ihres für die Drehmomenten- bzw. Leistungsregelung typischen Verlaufs als Drehmomenten-Kennlinie bezeichnet. Im vorliegenden Ausführungsbeispiel sind beide Verstellpumpen 1, 2 und damit ihre Drehmomenten-Kennlinien identisch, so daß lediglich eine dieser Kennlinien im Speicherteil des Mikrocomputers 26 gespeichert ist.The electronic control unit 26 is designed as a microcomputer, in the The characteristic curve KLg shown in FIG. 4 is stored in the memory part. Although this characteristic represents the working pressure p as a function of the delivery volume V of a variable displacement pump, it is below due to its for torque or power control typical course referred to as the torque characteristic. In the present Embodiment are both variable pumps 1, 2 and thus theirs Torque characteristics identical, so that only one of these characteristics in Memory part of the microcomputer 26 is stored.

Die Fläche pxV unter der Drehmomenten-Kennlinie KLg ist für jedes Fördervolumen V bzw. für jeden Arbeitsdruck p konstant und im vorliegenden Ausführungsbeispiel gleich dem Gesamtantriebsmoment des Antriebsmotors 6. Der Punkt P auf der Drehmomenten-Kennlinie KLg kennzeichnet den Übergang vom sogenannten Anfahrbereich (senkrechter Abschnitt von KLg) zum Regelbereich (hyperbolischer Abschnitt von KLg), und seinem Ordinatenwert entspricht der Sollwert des Gegendrucks an dem Regelventil 18, das derjenigen Verstellpumpe 1 bzw. 2 zugeordnet ist, die das Gesamtantriebsmoment überträgt bzw. übertragen soll. Der Ordinatenwert des Punktes P entspricht somit auch dem maximalen Drehmoment, das diese Verstellpumpe übertragen kann, das heißt im vorliegenden Fall dem Gesamtantriebsmoment des Antriebsmotors 6. Der Sollwert des Gegendrucks an dem der jeweils anderen Verstellpumpe zugeordneten Regelventil ist auf Null eingestellt, um zu verhindern, daß diese Verstellpumpe durch Antrieb des an sie angeschlossenen Verbrauchers den Antriebsmotor 6 überlastet.The area pxV under the torque characteristic curve KL g is constant for each delivery volume V or for each working pressure p and in the present exemplary embodiment is equal to the total drive torque of the drive motor 6. The point P on the torque characteristic curve KL g denotes the transition from the so-called approach range ( vertical section of KL g ) to the control range (hyperbolic section of KL g ), and its ordinate value corresponds to the target value of the back pressure at the control valve 18, which is assigned to the variable pump 1 or 2, which transmits or is to transmit the total drive torque. The ordinate value of point P thus also corresponds to the maximum torque that this variable displacement pump can transmit, that is to say in the present case the total drive torque of drive motor 6. The setpoint value of the counterpressure at the control valve assigned to the other variable displacement pump is set to zero in order to prevent that this variable pump overloads the drive motor 6 by driving the consumer connected to it.

Die Sollwertsumme dieser beiden Gegendruck-Sollwerte und damit die Summe der Drehmomente beider Verstellpumpen 1, 2, die nicht größer als das Gesamtantriebsmoment des Antriebsmotors 6 sein darf, ist ebenfalls im Speicherteil des Mikrocomputers 26 gespeichert und kann mittels der Sollwert-Einstellvorrichtung in Sollwerte beliebiger Größe aufgeteilt werden.The setpoint sum of these two counterpressure setpoints and thus the sum of the Torques of both variable pumps 1, 2, which are not greater than the total drive torque of the drive motor 6 may also be in the memory part of the microcomputer 26 stored and can be set to any desired values using the setpoint adjustment device Size.

Bei diesem System sowie insbesondere bei sogenannten Load-Sensing-Systemen, bei denen die Druckdifferenz über einem Wegeventil eines Verbrauchers konstant geregelt wird, tritt dabei das Problem auf, daß die Regelungen gegenüber Regelschwingungen sehr anfällig sind. Diese systembedingten Schwingungen sind mit konventionellen hydraulischen Reglersystemen nur schwer dämpfbar.In this system and in particular in so-called load-sensing systems, in which the pressure difference across a directional control valve of a consumer is constantly controlled The problem is that the regulations are very susceptible to control vibrations are. These system-related vibrations are with conventional hydraulic Controller systems are difficult to dampen.

Aufgabe der vorliegenden Erfindung ist es daher, Schwingungen in Regelkreisen mit Verstellpumpen, insbesondere in sogenannten Load-Sensing-Regelsystemen, auf einfache Weise zu verringern.The object of the present invention is therefore to include vibrations in control loops Variable pumps, especially in so-called load-sensing control systems, on simple Way to decrease.

Diese Aufgabe wird durch die Merkmale der Ansprüche 1 bzw. 6 gelöst.This object is solved by the features of claims 1 and 6, respectively.

Erfindungsgemäß ist also eine Vorrichtung gemäß dem Oberbegriff des Anspruches 1 vorgesehen, die weiterhin ein Druckbegrenzungsventil aufweist, durch das der maximale Gegendruck in dem Regelventil einstellbar ist. Eine elektronische Steuereinheit steuert das Druckbegrenzungsventil in Abhängigkeit von dem erfaßten Stellungssignal an.According to the invention is therefore a device according to the preamble of claim 1 provided that also has a pressure relief valve through which the maximum Back pressure in the control valve is adjustable. An electronic control unit controls this Pressure relief valve depending on the detected position signal.

Die elektronische Steuereinheit kann Kennlinien - Arbeitsdruck p in Abhängigkeit vom Förderstrom Q- konstanter Pumpenleistung und den zugehörigen, in dem Regelventil wirkenden Gegendruck berechnen. Eine einer gewünschten Pumpenleistung entsprechende Kennlinie ist auswählbar.The electronic control unit can produce characteristic curves - working pressure p as a function of Flow rate Q- constant pump output and the associated, in the control valve calculate the acting back pressure. One corresponding to a desired pump output Characteristic curve can be selected.

Vorteilhafterweise kann ein Drehzahlsensor vorgesehen sein, durch den die Drehzahl des die Verstellpumpe antreibenden Motors erfaßbar ist und bei Unterschreiten einer vorbestimmten Grenzdrehzahl eine Kennlinie auswählbar ist, die einer niedrigeren Pumpenleistung als die der zuvor gewählten Kennlinie entspricht.A speed sensor can advantageously be provided, by means of which the speed of the the variable pump driving motor can be detected and if the value falls below one a predetermined limit speed, a characteristic curve can be selected that a lower Pump output than that of the previously selected characteristic curve.

Das Druckbegrenzungsventil kann so ausgeführt sein, daß bei einem Ausfall der elektronischen Steuereinheit der größtmögliche Gegendruck in dem Regelventil zugelassen wird.The pressure relief valve can be designed so that in the event of a failure electronic control unit the greatest possible back pressure in the control valve becomes.

Eirre adaptive Anpassung der Regelparameter in der elektronischen Steuereinheit kann durch eine Vorrichtung zur Erfassung der Temperatur des Hydrauliköls ermöglicht werden.Eirre adaptive adjustment of the control parameters in the electronic control unit can enabled by a device for detecting the temperature of the hydraulic oil become.

Gemäß einem weiteren Aspekt der Erfindung ist ein Verfahren gemäß dem Oberbegriff des Anspruches 6 vorgesehen, wobei von der elektronischen Steuereinheit ein von dem Stellungssignal abhängiges Ansteuersignal erzeugt wird. Das Ansteuersignal wird einem Druckbegrenzungsventil zugeführt. Durch das Druckbegrenzungsventil wird der maximale Gegendruck in dem Regelventil eingestellt.According to a further aspect of the invention is a method according to the preamble of claim 6, wherein one of the electronic control unit Position signal dependent control signal is generated. The control signal is one Pressure relief valve supplied. Due to the pressure relief valve, the maximum Back pressure set in the control valve.

In der elektronischen Steuereinheit werden Kennlinien - Arbeitsdruck p in Abhängigkeit vom Förderstrom Q - konstanter Pumpenleistung und der zugehörige, in dem Regelventil wirkende Gegendruck berechnet. Eine einer gewünschten Pumpenleistung entsprechende Kennlinie wird dann ausgewählt.Characteristic curves - working pressure p become dependent in the electronic control unit of the flow rate Q - constant pump output and the associated, in the control valve acting back pressure calculated. One corresponding to a desired pump output Characteristic curve is then selected.

Ein Drehzahlsensor erfaßt die Drehzahl des die Verstellpumpe antreibenden Motors und bei Unterschreiten einer vorbestimmten Grenzdrehzahl wird eine Kennlinie ausgewählt, die einer niedrigeren Pumpenleistung als die der zuvor gewählten Kennlinie entspricht.A speed sensor detects the speed of the motor driving the variable pump and If the speed falls below a predetermined limit, a characteristic curve is selected which a lower pump output than that of the previously selected characteristic curve.

Bei einer Fehlfunktion des Drehzahlsensors wird automatisch eine einer niedrigeren Pumpenleistung entsprechende Kennlinie ausgewählt. In the event of a malfunction of the speed sensor, one of the lower ones will automatically be changed Pump performance corresponding characteristic selected.

Der maximale Gegendruck in dem Regelventil wird so gewählt, daß die zeitliche Änderung des Gegendrucks während des Wegevorgangs des Regelventils eine vorbestimmte Änderungsrate nicht überschreitet.The maximum back pressure in the control valve is chosen so that the time Change in back pressure while the control valve is moving does not exceed a predetermined rate of change.

Bei einem Ausfall der elektronischen Steuereinheit kann der größtmögliche Gegendruck in dem Regelventil zugelassen werden.In the event of a failure of the electronic control unit, the greatest possible back pressure in the control valve.

Der maximale Gegendruck in dem Regelventil kann so gewählt werden, daß die zeitliche Änderung der Leistung der Verstellpumpe eine vorbestimmte Änderungsrate nicht überschreitet.The maximum back pressure in the control valve can be chosen so that the time Change in the performance of the variable pump does not change a predetermined rate exceeds.

Die Temperatur des Hydrauliköls kann erfaßt werden und die Regelparameter in der elektronischen Steuereinheit werden dementsprechend adaptiv angepaßt.The temperature of the hydraulic oil can be recorded and the control parameters in the electronic control unit are adapted adaptively accordingly.

Die Stellung der Stelleinrichtung wird anhand des Stellungssignals über einen vorgegebenen Zeitraum aufgezeichnet und die Regelparameter werden abhängig von der Aufzeichnung verändert.The position of the actuating device is determined based on the position signal via a predetermined period and the control parameters are dependent on the Recording changed.

Die Erfindung wird aus der folgenden Beschreibung eines Ausführungsbeispiels bezugnehmend auf die begleitenden Zeichnungen näher ersichtlich. Es zeigen:

Figur 1
ein Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung bzw. eine Vorrichtung zur Ausführung des erfindungsgemäßen Verfahrens,
Figur 2
ein bekanntes Leistungsregelungssystem für Verstellpumpen,
Figur 3
eine Kennlinie eines Druckbegrenzungsventils, und
Figuren 4 und 5
ein Kennfeld bzw. eine Kennlinie, die in der elektronischen Steuereinheit gespeichert sind.
The invention will become more apparent from the following description of an embodiment with reference to the accompanying drawings. Show it:
Figure 1
an embodiment of a device according to the invention or a device for performing the method according to the invention,
Figure 2
a known power control system for variable pumps,
Figure 3
a characteristic of a pressure relief valve, and
Figures 4 and 5
a map or a characteristic curve, which are stored in the electronic control unit.

In Figur ist ein Ausführungsbeispiel der Erfindung dargestellt. Die Bauteile, die denen entsprechen, die bezugnehmend auf Figur 2 erläutert wurden, sind dabei mit denselben Bezugszeichen versehen. Figur 1 zeigt einen Motor 6, der eine Verstellpumpe 1 antreibt. Die Erfindung ist selbstverständlich auch Hydrauliksysteme anwendbar, bei dem mehrere Verstellpumpen von einem Motor angetrieben werden, wie bezugnehmend auf Figur 2 erläutert wurde. Das in Figur 1 dargestellte System stellt somit eine beliebig kombinierbare Universaleinheit dar. In the figure, an embodiment of the invention is shown. The components that those correspond, which were explained with reference to FIG. 2, are with the same Provide reference numerals. Figure 1 shows a motor 6 which drives a variable displacement pump 1. The invention is of course also applicable to hydraulic systems in which several Variable displacement pumps are driven by a motor, as referring to FIG. 2 was explained. The system shown in Figure 1 thus represents any combinable universal unit.

In dem in Figur 1 dargestellten Ausführungsbeispiel ist das Pumpenregelventil 18 in einem sogenannten Load-Sensing-System eingesetzt. Es hat dabei die Aufgabe, die Druckdifferenz über einem Wegeventil 46 vor einem Verbraucher 3 konstant zu halten, um den Wirkungsgrad der Hydraulik zu verbessern. Bei mehreren Verbrauchern wird der höchste Lastdruck berücksichtigt und der Druck der Verstellpumpe 1 diesem angepaßt. Die Load-Sensing-Regelung arbeitet wie folgt: Wenn der Verbraucherdruck in der Leitung 45 ansteigt, bewirkt dies ein Verschieben des Hauptkolbens des Regelventils 18 nach links. Somit wird eine Verbindung zwischen den Leitungen 23 und 20 hergestellt, was eine Erhöhung des Stelldrucks der Stelleinrichtung 7 bewirkt und somit ein Ausschwenken der Verstellpumpe 1. Somit bewirkt ein Ansteigen des Verbraucherdrucks45 auch ein Ansteigen des Systemdrucks vor dem Verbraucher-Wegeventil 46.In the embodiment shown in Figure 1, the pump control valve 18 is in one so-called load-sensing system used. It has the task of To keep the pressure difference across a directional valve 46 in front of a consumer 3 constant, to improve the efficiency of the hydraulics. If there are several consumers, the The highest load pressure is taken into account and the pressure of the variable pump 1 is adapted to this. The Load sensing control works as follows: If the consumer pressure in line 45 increases, this causes the main piston of the control valve 18 to be shifted to the left. A connection is thus established between the lines 23 and 20, which is a Increases the signal pressure of the actuating device 7 and thus swings out Variable pump 1. Thus, an increase in consumer pressure45 also causes System pressure upstream of consumer directional control valve 46.

Umgekehrt wird, wenn der Verbraucherdruck in der Leitung 45 absinkt, der Hauptkolben des Regelventils 18 nach rechts verschoben. Somit wird eine Verbindung der Leitungen 21 und 20 bewirkt, wodurch die Verstellpumpe 1 einschwenkt und der Systemdruck vor dem Wegeventil 46 des Verbrauchers 3 fällt. Somit bleibt das Druckgefälle über das Wegeventil 46 konstant.Conversely, when the consumer pressure in line 45 drops, the main piston of the control valve 18 shifted to the right. A connection of the lines 21 and 20 causes, whereby the variable pump 1 swivels and the system pressure before Directional control valve 46 of consumer 3 falls. Thus the pressure drop remains above that Directional control valve 46 constant.

Erfindungsgemäß ist weiterhin ein Schwenkwinkelaufnehmer 25 vorgesehen, der den Schwenkwinkel der Verstellpumpe 1 erfaßt und ein diesem proportionales Signal an eine elektronische Steuereinheit 40 abgibt. Die elektronische Steuereinheit 40 berechnet ein Kennfeld der Verstellpumpe 1, das heißt eine Vielzahl von Kennlinien (Fig. 4) - Arbeitsdruck p in Abhängigkeit vom Förderstrom Q - konstanter Pumpenleistung sowie der zugehörige, in dem Regelventil 18 wirkende Gegendruck und speichert es gegebenenfalls ab. Dieses Kennfeld ist, wie in Figur 4 dargestellt, beliebig verschiebbar, das heißt eine einer gewünschten Pumpenleistung entsprechende Kennlinie ist in der elektronischen Steuereinheit auswählbar. Wie in Figur 4 gezeigt wird die Auswahl einer bestimmten Kennlinie durch Variierung des in dem Regelventil 18 maximal zulässigen Gegendrucks. Die elektronische Steuereinheit 40 gibt ein Ansteuersignal an ein Druckbegrenzungsventil 42. Wenn der Druck im Steuerraum des Regelventils 18 den durch das Druckbegrenzungsventil 42 vorgewählten Maximaldruck übersteigt, so öffnet sich ein Kegel in dem Druckbegrenzungsventil 42 und es wird Öl von der Leitung 45 zum Tank 5 abgelassen. Somit wird der Druck im Steuerraum des Regelventils 18 begrenzt. Der Hauptkolben des Regelventils 18 verschiebt sich somit nach rechts, es wird eine Verbindung der Leitungen 23 und 20 geschaffen, die Verstellpumpe 1 schwenkt zurück und es stellt sich der gewünschte maximale Systemdruck am Eingang des Wegeventils 46 des Verbrauchers 3 ein. Es ist also eine Pumpensteuerung vorgesehen, bei der der Load-Sensing-Regelung eine elektrisch ansteuerbare Druckabschneidung überlagert wurde, wobei durch die elektronische Steuereinheit 40 verschiedenartige Funktionen realisiert werden können:

  • Die Leistung der Verstellpumpe 1 ist durch Wahl einer Kennlinie variabel.
  • Die Druckabschneidung durch das Druckbegrenzungsventil 42 ist variabel. So kann zum Beispiel mit 250 bar gearbeitet und mit 280 bar gefahren werden.
  • Durch Vorsehen eines Sensors 43, der die Drehzahl des die Verstellpumpe 1 antreibenden Motors 6 erfaßt und Zuführen dieses Drehzahlsignals zu der elektronischen Steuereinheit 40 kann für den Fall, daß der Motor 6 überlastet wird, durch die elektronische Steuereinheit 40 das Druckbegrenzungsventil 42 so angesteuert werden, daß die Leistung der Stellpumpe 1 herabgesetzt wird und der Antriebsmotor 6 somit in einen günstigeren Drehzahlbereich gebracht wird.
  • Bei einer Fehlfunktion des Drehzahlsensors 43 kann automatisch eine geringere Leistung der Pumpe 1 angesteuert werden.
  • Die Anstiegsgeschwindigkeit des Systemdrucks vor dem Wegeventil 46 kann auf einen vorgewählten Wert begrenzt werden.
  • Für den Fall, daß die elektronische Steuereinheit 40 eine Fehlfunktion aufweist, geht die Verstellpumpe automatisch auf einen Maximaldruck, der nur durch die Stellung einer Einstellschraube 47 an dem Druckbegrenzungsventil bedingt ist.
  • Das Stellungssignal von dem Schwenkwinkelsensor 25 kann beispielsweise in einem Speicher 41 der elektronischen Steuereinheit 40 über einen vorwählbaren Zeitraum aufgezeichnet werden. Für den Fall, daß aus der Aufzeichnung Schwingungen der Regelung zu erkennen sind, können somit die Regelparameter der elektronischen Steuereinheit 40 adaptiv verändert werden.
  • Alternativ oder zusätzlich kann die Temperatur des Hydrauliköls, beispielsweise in einem Tank 5, durch einen Temperatursensor 44 erfaßt werden und bei einer unzulässigen Erhöhung der Temperatur des Hydrauliköls in dem Tank 5 entsprechend die Regelparameter in der elektronischen Steuereinheit 40 adaptiv verändert werden.
According to the invention, a swivel angle sensor 25 is also provided, which detects the swivel angle of the variable pump 1 and outputs a signal proportional to this to an electronic control unit 40. The electronic control unit 40 calculates a characteristic diagram of the variable displacement pump 1, that is to say a large number of characteristic curves (FIG. 4) - working pressure p as a function of the flow rate Q - constant pump output and the associated counterpressure acting in the control valve 18 and, if necessary, stores it. As shown in FIG. 4, this characteristic diagram can be moved as desired, that is to say a characteristic curve corresponding to a desired pump output can be selected in the electronic control unit. As shown in FIG. 4, the selection of a specific characteristic curve is made by varying the maximum back pressure permitted in the control valve 18. The electronic control unit 40 gives a control signal to a pressure relief valve 42. When the pressure in the control chamber of the control valve 18 exceeds the maximum pressure preselected by the pressure relief valve 42, a cone in the pressure relief valve 42 opens and oil is drained from the line 45 to the tank 5 . The pressure in the control chamber of the control valve 18 is thus limited. The main piston of the control valve 18 thus moves to the right, a connection of the lines 23 and 20 is created, the variable pump 1 swivels back and the desired maximum system pressure at the input of the directional valve 46 of the consumer 3 is set. A pump control is therefore provided, in which an electrically controllable pressure cut-off was superimposed on the load-sensing control, wherein various functions can be implemented by the electronic control unit 40:
  • The performance of the variable displacement pump 1 can be varied by selecting a characteristic curve.
  • The pressure cutoff by the pressure relief valve 42 is variable. For example, you can work at 250 bar and drive at 280 bar.
  • By providing a sensor 43 which detects the speed of the motor 6 driving the variable displacement pump 1 and supplying this speed signal to the electronic control unit 40, in the event that the motor 6 is overloaded, the pressure control valve 42 can be controlled by the electronic control unit 40 so that the output of the control pump 1 is reduced and the drive motor 6 is thus brought into a more favorable speed range.
  • In the event of a malfunction of the speed sensor 43, a lower output of the pump 1 can be controlled automatically.
  • The rate of increase of the system pressure upstream of the directional valve 46 can be limited to a preselected value.
  • In the event that the electronic control unit 40 malfunctions, the variable pump automatically goes to a maximum pressure which is only due to the position of an adjusting screw 47 on the pressure relief valve.
  • The position signal from the swivel angle sensor 25 can be recorded, for example, in a memory 41 of the electronic control unit 40 over a preselectable period. In the event that oscillations of the regulation can be recognized from the recording, the regulation parameters of the electronic control unit 40 can thus be changed adaptively.
  • Alternatively or additionally, the temperature of the hydraulic oil, for example in a tank 5, can be detected by a temperature sensor 44 and, in the event of an inadmissible increase in the temperature of the hydraulic oil in the tank 5, the control parameters in the electronic control unit 40 are changed accordingly.

In Figur 1 ist eine Einheit dargestellt, bei der ein Motor 6 nur eine Pumpe 1 antreibt. Wie durch das Bezugszeichen indessen angedeutet ist, läßt sich das erfindungsgemäße Prinzip indessen leicht auf Systeme mit mehrere von einem Motor angesteuerten Verstellpumpen anwenden, beispielsweise für den Fall einer Summenleistungsregelung, wie sie aus der DE-PS 44 05 234 bekannt ist.1 shows a unit in which a motor 6 drives only one pump 1. How the principle of the invention can be indicated by the reference symbol however, easily on systems with several variable pumps driven by one motor apply, for example in the case of a total power control, such as from the DE-PS 44 05 234 is known.

Claims (14)

  1. Device for the output regulation of at least one variable displacement pump (1), delivering into a working line, driven by a motor, through adjustment of its displacement by means of a setting device (7) biased in the direction of maximum displacement and which can be acted upon with a setting pressure (20), having a regulation valve (18) associated with the setting device, which regulation valve is acted upon by a counter-pressure corresponding to the working pressure in the working line, whereby the regulation valve (18) responds when the control pressure is greater than the counter-pressure, and so regulates the setting pressure action on the setting device (7) in the direction of a reduction of the displacement of the variable displacement pump (1) that the product of working pressure and output corresponds to a predetermined value,
    whereby a device (25) is provided through which the setting of the setting device (7) can be detected and which delivers to an electronic control unit (40) a setting signal proportional to the setting, characterised in that a pressure limiting valve (42) is provided by means of which the maximum counter-pressure in the regulation valve (18) can be set,
    whereby the electronic control unit (40) controls the pressure limiting valve (42) in dependence upon the detected setting signal.
  2. Device according to claim 1, characterised in that there can be calculated in the electronic control unit (40) characteristic lines - working pressure p in dependence upon flow Q - of constant pump output, and the associated counter-pressure effective in the regulation valve (18), and a characteristic line corresponding to a desired pump output can be selected.
  3. Device according to claim 2, characterised in that there is provided a speed of rotation sensor by means of which the speed of rotation of the motor driving the variable displacement pump (1) can be detected, and when a predetermined limit speed of rotation is undershot, a characteristic line can be selected which corresponds to a lesser pump output than the previously selected characteristic line.
  4. Device according to any preceding claim, characterised in that the pressure limiting valve is so constituted that in the case of a failure of the electronic control unit (40) the maximum possible counter-pressure in the regulation valve (18) is permitted.
  5. Device according to any preceding claim, characterised in that for adaptive alteration of the regulation parameters there is provided a device for detecting the temperature of the hydraulic oil.
  6. Method of regulating the output of a variable displacement pump (1), delivering into a working line, driven by a motor, through adjustment of its displacement by means of a respective setting device (7) biased in the direction of maximum displacement, which can be acted upon with a setting pressure (20), having a regulation valve (18) associated with the setting device, which regulation valve is acted upon by a counter-pressure corresponding to the working pressure in the working line, whereby the regulation valve (18) responds when the control pressure is greater than the counter-pressure, and so regulates the setting pressure action on the setting device (7) in the direction of a reduction of the displacement of the variable displacement pump (1) that the product of working pressure and output corresponds to a predetermined value, whereby the setting of the setting device is detected and there is delivered to an electronic control unit (40) a setting signal proportional to the detected setting,
    characterised in that
    there is generated by the electronic control unit (40) a control signal dependent upon the setting signal,
    the control signal is delivered to a pressure limiting valve (42) and
    by means of the pressure limiting valve (42) the maximum counter-pressure in the regulation valve (18) is set.
  7. Method according to claim 6, characterised in that there are calculated in the electronic control unit (40) characteristic lines - working pressure p in dependence upon flow Q - of constant pump output, and the associated counter-pressure effective in the regulation valve (18), and a characteristic line corresponding to the desired pump output is selected.
  8. Method according to claim 7, characterised in that a speed of rotation sensor detects the speed of rotation of the motor driving the variable displacement pump, and upon a predetermined limit speed of rotation being exceeded a characteristic line is selected which corresponds to a lesser output than the previously selected characteristic line.
  9. Method according to claim 8, characterised in that in the case of a fault of the speed of rotation sensor a characteristic line corresponding to a lesser pump output is automatically selected.
  10. Method according to any of claims 6 to 9, characterised in that the maximum counter-pressure in the regulation valve (18) is so selected that the temporal change of the counter-pressure during the regulation action of the regulation valve (18) does not exceed a predetermined rate of change.
  11. Method according to any of claims 6 to 10, characterised in that in the case of a failure of the electronic control unit (40) the maximum possible counter-pressure in the regulation valve (18) is permitted.
  12. Method according to any of claims 6 to 11, characterised in that the maximum counter-pressure in the regulation valve (18) is so selected that the temporal change of the output of the variable displacement pump (1) does not exceed a predetermined rate of change.
  13. Method according to any of claims 6 to 12, characterised in that the temperature of the hydraulic oil in a tank is detected and the regulation parameters in the electronic control unit (40) are adaptively altered.
  14. Method according to any of claims 6 to 13, characterised in that the setting of the setting device (7) is recorded over a predetermined period of time by means of the setting signal, and in dependence upon the recording the regulation parameters are altered.
EP96934569A 1995-10-17 1996-10-08 Output regulation with load sensing Expired - Lifetime EP0856107B1 (en)

Applications Claiming Priority (3)

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DE19538649A DE19538649C2 (en) 1995-10-17 1995-10-17 Power control with load sensing
DE19538649 1995-10-17
PCT/EP1996/004355 WO1997014889A1 (en) 1995-10-17 1996-10-08 Output regulation with load sensing

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EP0856107A1 EP0856107A1 (en) 1998-08-05
EP0856107B1 true EP0856107B1 (en) 1999-09-08

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JP (1) JP3909356B2 (en)
KR (1) KR100337565B1 (en)
DE (2) DE19538649C2 (en)
WO (1) WO1997014889A1 (en)

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DE4405234C1 (en) * 1994-02-18 1995-04-06 Brueninghaus Hydraulik Gmbh Arrangement for the cumulative power regulation of at least two hydrostatic variable-displacement pumps

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10006659B4 (en) 2000-02-15 2018-06-28 Brueninghaus Hydromatik Gmbh Control device for a hydraulic pump
CN104989692A (en) * 2015-07-20 2015-10-21 圣邦集团有限公司 Compound control-type variable pump and control method thereof

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US6048177A (en) 2000-04-11
DE59603019D1 (en) 1999-10-14
JP3909356B2 (en) 2007-04-25
KR100337565B1 (en) 2002-07-18
DE19538649A1 (en) 1997-04-24
DE19538649C2 (en) 2000-05-25
JPH11513771A (en) 1999-11-24
KR19990036160A (en) 1999-05-25
EP0856107A1 (en) 1998-08-05
WO1997014889A1 (en) 1997-04-24

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