EP0745189A1 - Device for regulating the total output of at least two hydrostatic variable displacement pumps - Google Patents

Device for regulating the total output of at least two hydrostatic variable displacement pumps

Info

Publication number
EP0745189A1
EP0745189A1 EP95908254A EP95908254A EP0745189A1 EP 0745189 A1 EP0745189 A1 EP 0745189A1 EP 95908254 A EP95908254 A EP 95908254A EP 95908254 A EP95908254 A EP 95908254A EP 0745189 A1 EP0745189 A1 EP 0745189A1
Authority
EP
European Patent Office
Prior art keywords
pressure
control
variable displacement
variable
regulating
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.)
Granted
Application number
EP95908254A
Other languages
German (de)
French (fr)
Other versions
EP0745189B1 (en
Inventor
Mikko Erkkilae
Karl-Heinz Vogl
Günter FERTIG
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
Original Assignee
Brueninghaus Hydromatik GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Brueninghaus Hydromatik GmbH filed Critical Brueninghaus Hydromatik GmbH
Publication of EP0745189A1 publication Critical patent/EP0745189A1/en
Application granted granted Critical
Publication of EP0745189B1 publication Critical patent/EP0745189B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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
    • 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
    • F04B49/08—Regulating by delivery pressure
    • 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
    • F04B2201/00—Pump parameters
    • F04B2201/12—Parameters of driving or driven means
    • F04B2201/1205—Position of a non-rotating inclined plate

Definitions

  • the invention relates to a device for total power control of at least two hydrostatic variable pumps according to the preamble of claim 1.
  • Such a device is known for example from DE-PS 4208925.
  • the total power control of this known device distributes the device drive power available from the drive motor between the two variable pumps. It bt t as ever. Power control on the principle of adjusting the delivery volume of the variable pumps as a function of the working pressure such that the respective maximum drive torque or, at constant drive speed, the maximum power consumption of the variable pumps remains essentially constant over the entire working range.
  • the Arb generated by each variable e its founded acts jerk flask over a ⁇ and a lever arm acted upon by that a two-armed pivot lever on the respective associated control valve.
  • the counter pressure at each control valve is generated by two adjustable pressure springs, one of which acts directly on the control valve and the other via the lever arm of the swivel lever acted upon by the control pressure.
  • a further control pressure which corresponds to the working pressure generated by the respective other variable pump, acts against the pressure of the compression spring acting on the lever arm.
  • the sum of the setting values of both pressure springs determines the maximum torque of the respective variable pump and corresponds the total drive torque of the drive motor. This torque can be transmitted by each variable pump as long as there is no second control pressure at the associated control valve, ie as long as the other variable pump does not absorb any torque.
  • each variable pump With increasing torque consumption of the latter variable pump, the back pressure at the control valve of the first variable pump, and thus its torque setting, is reduced to a minimum value, which occurs when the further control pressure is equal to or greater than the pressure, as a result of the corresponding increase in the further control pressure the compression spring acting on the lever arm.
  • the torque absorption of each variable pump is thus limited to the value (setpoint of the individual drive torque) which corresponds to the setting value of the compression spring acting directly on the respectively associated control valve.
  • a higher torque absorption of each of the two variable displacement pumps is possible, specifically if the setpoint of the respective individual drive torque is increased by a corresponding change in the setting value of the compression spring acting directly on the respective control valve and, as a result, also the setting values of the three remaining compression springs, or if the torque absorption of the other variable displacement pump falls below the setting value of the compression spring acting directly on the associated control valve.
  • the setpoint values of the individual drive torques are specified in the simplest manner by means of the setpoint value setting device, the electronic control unit dividing the setpoint value stored in its memory part, which preferably corresponds to the total drive torque of the drive motor, in accordance with the setpoint value specification and designed by actuation of the preferably magnetically controlled proportional magnets electrical control elements with control signals that meet the specified Correspond to setpoints, adjust the control valves to the corresponding back pressures and thus determine the maximum torque of each variable pump.
  • the time-consuming and comparatively imprecise setting of four compression springs required by the prior art is eliminated.
  • the device according to the invention has a considerably simpler structure than the device known from the prior art, which comprises the compression springs, the swivel levers, the pressure pistons which can be displaced in the actuating pistons of the actuating devices, and the hydraulic control lines for the others which counteract the counterpressures Control pressures required.
  • the electronic control unit which is preferably in the form of a microcomputer, the electrical control elements, the measuring sensors, which are preferably designed as inductive displacement sensors that detect the respective position of the actuating devices, and the electrical signal lines are easy to install, easy to maintain, enable uncomplicated troubleshooting and, overall, more accurate Total power control.
  • Fig. 1 is a circuit diagram of a device for total power control of two hydrostatic variable pumps
  • FIG. 2 A diagram that shows the torque characteristic of the hydrostatic adjusting pump according to FIG. 1.
  • hydrostatic regulating pumps 1 and 2 such as.
  • Axi alcohol piston pumps in swash plate design can be device 3 to a consumer, not shown, such as the chassis and the slewing motor of an excavator, and connected via a suction line 4 to a tank 5.
  • Both variable pumps 1, 2 are driven by a common drive motor 6, such as an internal combustion engine, and rotate at the same speed.
  • An adjusting device consisting of two single-acting hydraulic actuating cylinders 7, 8 is provided to adjust their delivery volume.
  • An actuating piston 9 is arranged displaceably in each actuating cylinder 7, 8 and is coupled via a piston rod 10 to an actuator 11 or 12 of the respective variable pump 1 or 2.
  • the pressure chambers 13 of the actuating cylinders 7 are each connected via an actuating pressure line 14 to the working line 3 assigned to the respective variable pump 1 or 2.
  • a pressure line 15 leads to the pressure chambers 13 of the actuating cylinders 8, in each of which a pressure spring 16 is arranged, which, if necessary supported by the working pressure taken from the respective working line 3 via the respective pressure line 15, via the piston 9, the piston rod 10 and the actuator 12 act on the swash plate of the variable displacement pump 1 or 2 in the direction of the maximum delivery volume.
  • the piston surfaces 10 facing away from the piston rods of the actuating pistons 9 in the actuating cylinders 7 are larger than those of the actuating pistons 9 arranged in the actuating cylinders 8, so that working pressure which is generated during the operation of the variable displacement pumps 1, 2 via the actuating pressure lines 14 in the pressure chambers 13 of the actuating cylinders 7 builds up as a control pressure, the swash plate of the respective variable displacement pump 1, 2 is adjusted in the direction of the minimum delivery volume via the piston 9 and the piston rod 10.
  • One adjustable stop 17 each in the pressure chambers 13 of the actuating cylinders 7 serves to limit the maximum delivery volume of the variable displacement pumps 1, 2 to different values.
  • Each control valve 18 is arranged in the actuating pressure lines 14 and divides them into a respective actuating pressure line section 19, 20 leading to the respective working line 3 or to the respective actuating cylinder 7.
  • each Control valve 18 is designed as a continuously adjustable 3/2-way valve and has two working connections to the actuating pressure line sections 19 and 20 as well as a working connection to a discharge line 21 leading to the tank 5, into which a leak oil line 22 of the respective variable pump 1 or 2 flows.
  • a control pressure line 23 leads from each signal pressure line section 19 to a control connection of the associated control valve 18 and enables its adjustment in the direction of an end position in which the work connections to the signal pressure line section 20 and the relief line 21 are open and the remaining work connection is blocked.
  • the device for total power control of the two variable displacement pumps 1, 2 comprises two electrical control elements 24, two measuring value transmitters 25, an electronic control unit 26 and a setpoint adjustment device 27 associated therewith.
  • the electrical control elements 24 are designed as force-controlled proportional magnets and are each assigned to one of the control valves 18 for the purpose of generating a counter pressure counteracting the control pressure. Are you over j? a control signal line 28 is connected to the electronic control unit 26.
  • the transducers 25 are designed as inductive displacement transducers, which are assigned to the piston rod 10 of the respective actuating cylinder 7 for the purpose of detecting the respectively set delivery volume of the variable pumps 1, 2 and are connected to the electronic control unit 26 via a signal line 29.
  • the electronic control unit 26 is designed as a microcomputer, in the memory part of which a fi g. 2 shown maps are never stored in KL.
  • this characteristic curve represents the working pressure pin as a function of the delivery volume V of an adjusting pump, it is based below on the torque and power regulation typical for the torque and power regulation. 1 characteristic curve. Both are in the present embodiment
  • the area pxV below the torque characteristic curve KL 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 denotes the transition from
  • the setpoint sum of these two counterpressure setpoints and thus the sum of the torques of the two variable pumps 1, 2, which must not be greater than the total drive torque of the drive motor 6, is likewise stored in the memory part 25 of the microcomputer 26 and can be set by means of the setpoint setting device direction into target values of any size.
  • variable pumps 1, 2 are driven by the drive motor 6 at the same speed.
  • setpoint value setting device 27 the setpoint sum of the counterpressure setpoints for both control valves 18, which is stored in the microcomputer 26 and corresponds to the total drive torque of the drive motor 6, is divided according to the desired operating mode and thus each
  • variable pump 1, 2 the maximum torque that it can generate specified, for example for variable pump 1 60% and for variable pump 2 40% of the total drive torque.
  • the microcomputer 26 sets for both variable displacement pumps 1, 2 the torque characteristic curves corresponding to the predetermined back pressure setpoints, ie those characteristic curves whose transitions from their vertical sections to their hyperbolic sections are identified by the points P, and P ⁇ , the ordinate values of which correspond to the specified back pressure setpoints. This results in the case of the variable displacement pump 1, the characteristic curve KL-, the torque corresponding to the back pressure setpoint of 60% of the setpoint total and in the case of the variable displacement pump 2, the characteristic curve KL of the torque corresponding to the backpressure setpoint of 40% of the setpoint total.
  • the microcomputer 26 takes the setting of the characteristic curves KL corresponding to the predetermined back pressure setpoints in the exemplary embodiment described here by lowering the hyperbolic section from KL to the points P ,, P ? in front;
  • the microcomputer 26 now processes each of these two predetermined setpoints into a corresponding control signal and outputs this to the proportional magnet 24 of the respectively associated control valve 18, which generates a corresponding counter pressure.
  • variable pumps 1, 2 load the drive motor 6 with the maximum torque to which they are set and in this way together with the total drive torque that the drive motor 6 applies.
  • control valve 18 responds according to the control pressure and regulates it
  • the sensors 25 record the respective position of the actuating pistons 9 of the actuating cylinders 7 and thus the delivery volume of the respectively assigned variable displacement pumps 1 and 2 and generate corresponding signals.
  • the electronic control unit 26 picks up these signals and uses them to determine for each variable pump 1, 2 that working pressure p which corresponds to the delivery volume V detected by the respective transducer 25 on the associated torque characteristic curve KL or L. This working pressure p is processed in the microcomputer 26 to produce a corresponding control signal and is output to the respectively associated proportional magnet 24 to generate a correspondingly higher back pressure at the respective control valve 18.
  • variable pumps 1, 2 are pivoted back both individually and together with an increase in the working pressure generated by them to a smaller delivery volume so that the individual drive torques corresponding to the set back pressure setpoints or the total drive torque corresponding to the setpoint total is not exceeded.
  • the setpoint sum stored in the memory part of the microcomputer 26 can also be divided with the setpoint setting device 27 into individual setpoints other than those mentioned above, so that it is possible, for example, to adjust the variable pump 1 to 100% of the total drive torque, for example for driving of the undercarriage, and accordingly to adjust the variable displacement pump 2 to zero percent total drive torque.
  • the variable pump 2 is set to 100% and the variable pump 1 accordingly to zero percent total drive torque.
  • the proportional magnets can each be assigned a compression spring, so that the back pressure at each control valve 18 results from the force of the proportional magnet and the adjusting force of this compression spring.
  • the setting force of each of these compression springs can correspond to the setpoint sum ⁇ of the counterpressure setpoints, and in this case each proportional magnet has an opposite direction of action, one of which corresponds to the direction of action of the control pressure if this control pressure is less than the counterpressure and its setpoint is less than the setpoint sum is, and the other coincides with the direction of action of the compression spring when the control pressure is greater than the back pressure.

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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)

Abstract

A device is disclosed for regulating the total output of several variable displacement pumps (1, 2) provided each with a regulating valve (18) for regulating the displaced volume. A control pressure that corresponds to the working pressure of the variable displacement pumps is applied to the regulating valves (18) against a counterpressure. The regulating valve (18) responds when the control pressure exceeds the counterpressure, regulating the variable displacement pump according to a characteristic curve (KL) of constant torque. In order to adjust the individual driving torques in a simple manner and to prevent the torques from exceeding the set values, an electronic control unit (16) is connected to the measurement sensor (25) that senses the volumes displaced by the variable displacement pumps. The electronic control unit (16) stores the sum of the set values of the counterpressures and the torque characteristic curves (KL) of the variable displacement pumps and has a set value regulator (27) that distributes the set value sum. The electronic control unit (16) further sets said torque characteristic curves (KL1, KL2), transmits control signals to the associated control element (24) that generates counterpressures corresponding to predetermined counterpressure set values, senses the working pressure (p) corresponding to the displaced volume (V) on the torque characteristic curve (KL1, KL2) when the regulating valves respond, converts said working pressure (p) into a control signal and transmits said signal to the control element that generates a counterpressure.

Description

Vorrichtung zur Summenleistungsregelung von wenigstens zwei hydrostatischen VerstellpumpenDevice for total power control of at least two hydrostatic variable pumps
Die Erfindung betrifft eine Vorrichtung zur Summenleistungsregelung von wenigstens zwei hydrostatischen Verstellpumpen nach dem Oberbegriff des Anspruches 1.The invention relates to a device for total power control of at least two hydrostatic variable pumps according to the preamble of claim 1.
Eine derartige Vorrichtung ist beispielsweise aus der DE-PS 4208925 bekannt. Die Summenleistungsregelung dieser bekannten Vorrichtung verteilt die vom Antriebsmotor zur Verfügung g- eilte Ger tantriebsleistung zwischen den beiden Verstellpumpen. Sie bt t wie jeα. Leistungsregelung auf dem Prinzip der Verstellung des Fördervolumens der Verstellpumpen in Abhängigkeit vom Arbeitsdruck derart, daß das jeweils maximale Antriebsmo¬ ment bzw. bei konstanter Antriebsdrehzahl die jeweils maximale Leistungsauf¬ nahme der Verstellpumpen über den gesamten Arbeitsbereich im wesentlichen konstant bleibt.Such a device is known for example from DE-PS 4208925. The total power control of this known device distributes the device drive power available from the drive motor between the two variable pumps. It bt t as ever. Power control on the principle of adjusting the delivery volume of the variable pumps as a function of the working pressure such that the respective maximum drive torque or, at constant drive speed, the maximum power consumption of the variable pumps remains essentially constant over the entire working range.
Der von jeder Verstellpumpe erzeugte Arbeitsdruck wirkt bei der bekannten Vorrichtung als Steuerdruck über einen ^ruckkolben und einen von diesem beaufschlagten Hebelarm eines zweiarmigen Schwenkhebels auf das jeweils zugeordnete Regelventil. Der Druckkolben ist im Stellkolben der als Stellzylinder ausgebildeten, jeweils zugeordn*^ --<n Stelleinrichtung- ver¬ schiebbar angeordnet und wirkt derart auf .≤n Hebelarm, daß dessen Hebellä'nge sich bei Verschiebung des Stellkolbens im Sinne einer Verringe¬ rung des Fördervolumens der Verstellpumpe so verkürzt, daß der Arbeitsdruck im gleichen Verhältnis ansteigen kann, wie sich das Fördervolumen der Verstellpumpe verringert. Au diese Weise wird das Produkt aus Arbeitsdruck und Fördervolumen konstant gehalten.The Arb generated by each variable e itsdruck acts jerk flask over a ^ and a lever arm acted upon by that a two-armed pivot lever on the respective associated control valve. In the known apparatus as a control pressure The plunger is formed in the adjusting piston of the adjusting cylinder, respectively Settings Associated * ^ - <n Stelleinrichtung- ver¬ slidably disposed and acts on lever arm .≤n that its Hebellä 'length on displacement of the actuating piston in the sense of Verringe¬ tion of Delivery volume of the variable pump is reduced so that the working pressure can increase in the same ratio as the delivery volume of the variable pump decreases. In this way, the product of working pressure and delivery volume is kept constant.
Der Gegendruck an jedem Regelventil wird durch zwei einstellbare Druckfedern erzeugt, deren eine direkt und deren andere über den vom Steuerdruck beaufschlagten Hebelarm des Schwenkhebels auf das Regelventil wirkt. Hn weiterer Steuerdruck, der dem von der jeweils anderen Verstellpumpe erzeugten Arbeitsdruck entspricht, wirkt gegen den Druck der den Hebelarm beaufschlagenden Druckfeder. Die Summe der Einstellwerte beider Druckfedern bestimmt das maximale Drehmoment der jeweiligen Verstellpumpe und entspricht dem Gesamtantriebsdrehmoment des Antriebsmotors. Dieses Drehmoment kann von jeder Verstellpumpe so lange übertragen werden, wie kein zweiter Steuerdruck am zugeordneten Regelventil ansteht, d.h. so lange, wie die jeweils andere Verstell pumpe kein Drehmoment aufnimmt.The counter pressure at each control valve is generated by two adjustable pressure springs, one of which acts directly on the control valve and the other via the lever arm of the swivel lever acted upon by the control pressure. A further control pressure, which corresponds to the working pressure generated by the respective other variable pump, acts against the pressure of the compression spring acting on the lever arm. The sum of the setting values of both pressure springs determines the maximum torque of the respective variable pump and corresponds the total drive torque of the drive motor. This torque can be transmitted by each variable pump as long as there is no second control pressure at the associated control valve, ie as long as the other variable pump does not absorb any torque.
Mit zunehmender Drehmomentaufnahme der letzteren Verstellpumpe verringert sich infolge des entsprechenden Anstiegs des weiteren Steuerdrucks der Gegendruck am Regel ventil der ersteren Verstell pumpe und damit dessen Dreh omenteinstellung bis auf einen minimalen Wert, der sich dann einstellt, wenn der weitere Steuerdruck gleich oder größer als der Druck der auf den Hebelarm wirkenden Druckfeder ist. Damit ist die Drehmomentaufnahme jeder Verstellpumpe auf den Wert (Sollwert des Einzel antriebsdrehmoments) be¬ schränkt, der dem Einstellwert der das jeweils zugeordnete Regelventil direkt beaufschlagenden Druckfeder entspricht. Eine höhere Drehmomentaufnah¬ me jeder der beiden Verstellpumpen ist möglich, und zwar dann, wenn der Sollwert des jeweiligen Einzelantriebsdrehmomentes durch entsprechende Veränderung des Einstellwertes der das jeweilige Regelventil direkt beaufschlagenden Druckfeder und als Folge davon auch der Einstellwerte der drei verbleibenden Druckfedern erhöht wird, oder wenn die Drehmomentaufnahme der jeweils anderen Verstell pumpe unter den Einstell wert der das zugeordnete Regelventil direkt beaufschlagenden Druckfeder fällt.With increasing torque consumption of the latter variable pump, the back pressure at the control valve of the first variable pump, and thus its torque setting, is reduced to a minimum value, which occurs when the further control pressure is equal to or greater than the pressure, as a result of the corresponding increase in the further control pressure the compression spring acting on the lever arm. The torque absorption of each variable pump is thus limited to the value (setpoint of the individual drive torque) which corresponds to the setting value of the compression spring acting directly on the respectively associated control valve. A higher torque absorption of each of the two variable displacement pumps is possible, specifically if the setpoint of the respective individual drive torque is increased by a corresponding change in the setting value of the compression spring acting directly on the respective control valve and, as a result, also the setting values of the three remaining compression springs, or if the torque absorption of the other variable displacement pump falls below the setting value of the compression spring acting directly on the associated control valve.
Es ist Aufgabe der Erfindung, eine Vorrichtung der eingangs genannten Art so weiterzubilden, daß die Sollwerte der Einzel antriebsdrehmomente der Ver¬ stellpumpen in einfacher Weise verstellt werden können und eine den jeweils eingestellten Wert übersteigende Drehmomentaufnahme verhindert wird.It is an object of the invention to develop a device of the type mentioned at the outset in such a way that the setpoints of the individual drive torques of the variable displacement pumps can be adjusted in a simple manner and a torque absorption which exceeds the respectively set value is prevented.
Diese Aufgabe wird durch die kennzeichnenden Merkmale des Anspruches 1 gelöst. Die Sollwerte der Einzel antriebsdrehmomente werden in einfachster Weise mittels der Sollwert-Einstelleinrichtung vorgegeben, wobei die elektronische Steuereinheit die in ihrem Speicherteil gespeicherte Sollwert- summe, die vorzugsweise dem Gesamtantriebsdrehmoment des Antriebsmotors entspricht, entsprechend der Sollwertvorgabe aufteilt und durch Ansteuerung der vorzugsweise als kraftgeregelte Proportionalmagneten ausgebildeten elektrischen AnSteuerelemente mit Steuersignalen, die den vorgegebenen Sollwerten entsprechen, die Regelventile auf entsprechende Gegendrücke einstellt und damit das jeweils maximale Drehmoment jeder Verstellpumpe bestimmt. Das gemäß dem Stand der Technik erforderliche zeitraubende und vergleichsweise ungenaue Einstellen von vier Druckfedern entfällt. Da der für jede Verstellpumpe vorgegebene Sollwert des Einzelantriebsdrehmomentes nur durch erneutes Aufteilen der Sollwertsumme mittels der Sollwert-Ein- stelleinrichtung verändert werden kann, ist eine den jeweils eingestellten Sollwert übersteigende Drehmomentaufnahme der Verstellpumpe im Gegensatz zu der aus dem Stand der Technik bekannten Vorrichtung nicht möglich, bei der sich eine Sollwertveränderung sozusagen automatisch bei sich ändernder Drehmomentaufnahme der jeweils anderen Verstellpumpe ergibt. Die erfindungs¬ gemäße Vorrichtung ist hinsichtlich ihres hydraulischen Systems erheblich einfacher aufgebaut als die aus dem Stand der Technik bekannte Vorrichtung, die die Druckfedern, die Schwenkhebel, die in den Stellkolben der Stelleinrichtungen verschiebbaren Druckkolben und die hydraulischen Steuer¬ leitungen für die den Gegendrücken entgegenwirkenden weiteren Steuerdrücke benötigt. Die vorzugsweise als Mikrocomputer ausgebildete elektronische Steuereinheit, die elektrischen AnSteuerelemente, die Meßwertgeber, die vorzugsweise als die jeweilige Stellung der Stelleinrichtungen erfassende induktive Wegaufnehmer ausgebildet sind, sowie die elektrischen Signallei- tungen sind einfach zu installieren, wartungsfreundlich, ermöglichen eine unkomplizierte Fehlersuche sowie insgesamt eine genauere Summenleistungsre¬ gelung.This object is achieved by the characterizing features of claim 1. The setpoint values of the individual drive torques are specified in the simplest manner by means of the setpoint value setting device, the electronic control unit dividing the setpoint value stored in its memory part, which preferably corresponds to the total drive torque of the drive motor, in accordance with the setpoint value specification and designed by actuation of the preferably magnetically controlled proportional magnets electrical control elements with control signals that meet the specified Correspond to setpoints, adjust the control valves to the corresponding back pressures and thus determine the maximum torque of each variable pump. The time-consuming and comparatively imprecise setting of four compression springs required by the prior art is eliminated. Since the setpoint of the individual drive torque specified for each variable pump can only be changed by dividing the setpoint total again by means of the setpoint adjustment device, in contrast to the device known from the prior art, it is not possible to take up the torque of the variable pump that is set in each case, in which a setpoint change occurs automatically, so to speak, when the torque consumption of the other variable pump changes. In terms of its hydraulic system, the device according to the invention has a considerably simpler structure than the device known from the prior art, which comprises the compression springs, the swivel levers, the pressure pistons which can be displaced in the actuating pistons of the actuating devices, and the hydraulic control lines for the others which counteract the counterpressures Control pressures required. The electronic control unit, which is preferably in the form of a microcomputer, the electrical control elements, the measuring sensors, which are preferably designed as inductive displacement sensors that detect the respective position of the actuating devices, and the electrical signal lines are easy to install, easy to maintain, enable uncomplicated troubleshooting and, overall, more accurate Total power control.
Die Erfindung ist nachstehend anhand eines bevorzugten Ausführungsbeispiels unter Bezugnahme auf die Zeichnung näher beschrieben. Es zeigen:The invention is described below with reference to a preferred embodiment with reference to the drawing. Show it:
Fig. 1 ein Schaltschema einer Vorrichtung zur Summenleistungsregelung von zwei hydrostatischen Verstellpumpen, undFig. 1 is a circuit diagram of a device for total power control of two hydrostatic variable pumps, and
Fig . 2 ei n Di agramm, das di e Drehmomenten-Kennl ini e der hydrostati schen Verstel l pumpe nach Fig. 1 zei gt .Fig. 2 A diagram that shows the torque characteristic of the hydrostatic adjusting pump according to FIG. 1.
Die i n Fig. 1 dargestel lten hydrostati schen Verstel lpumpen 1 und 2 , wie z .B. Axi alkol benpumpen i n Schrägschei benbauwei se, sind über je ei ne Arbeitslei- tung 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 einfach¬ wirkenden hydraulischen Stel 1Zylindern 7, 8 vorgesehen.The illustrated in Fig. 1 hydrostatic regulating pumps 1 and 2, such as. Axi alcohol piston pumps in swash plate design, can be device 3 to a consumer, not shown, such as the chassis and the slewing motor of an excavator, and connected via a suction line 4 to a tank 5. Both variable pumps 1, 2 are driven by a common drive motor 6, such as an internal combustion engine, and rotate at the same speed. An adjusting device consisting of two single-acting hydraulic actuating cylinders 7, 8 is provided to adjust their delivery volume.
In jedem Stellzylinder 7, 8 ist ein Stellkolben 9 verschiebbar angeordnet und über eine Kolbenstange 10 mit einem Stellglied 11 bzw. 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 zuordnete 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, ggfs. 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 Verstell¬ pumpe 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 über 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.An actuating piston 9 is arranged displaceably in each actuating cylinder 7, 8 and is coupled via a piston rod 10 to an actuator 11 or 12 of the respective variable pump 1 or 2. Each actuating piston 9, with its larger piston surface facing away from the piston rod 10, delimits a pressure chamber 13 in the respective actuating cylinder 7 or 8. The pressure chambers 13 of the actuating cylinders 7 are each connected via an actuating pressure line 14 to the working line 3 assigned to the respective variable pump 1 or 2. From each of these working lines 3, a pressure line 15 leads to the pressure chambers 13 of the actuating cylinders 8, in each of which a pressure spring 16 is arranged, which, if necessary supported by the working pressure taken from the respective working line 3 via the respective pressure line 15, via the piston 9, the piston rod 10 and the actuator 12 act on the swash plate of the variable displacement pump 1 or 2 in the direction of the maximum delivery volume. The piston surfaces 10 facing away from the piston rods of the actuating pistons 9 in the actuating cylinders 7 are larger than those of the actuating pistons 9 arranged in the actuating cylinders 8, so that working pressure which is generated during the operation of the variable displacement pumps 1, 2 via the actuating pressure lines 14 in the pressure chambers 13 of the actuating cylinders 7 builds up as a control pressure, the swash plate of the respective variable displacement pump 1, 2 is adjusted in the direction of the minimum delivery volume via the piston 9 and the piston rod 10. One adjustable stop 17 each in the pressure chambers 13 of the actuating cylinders 7 serves to limit the maximum delivery volume of the variable displacement 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 ^telldruckleitungsabschnitt 19, 20 auf. Jedes Regelventil 18 ist ein als st ig verstellbares 3/2-Wegeventil ausgebildet und weist zwei Arbeitsanschlüsse an die Stel ldruckleitungsabschnitte 19 bzw. 20 sowie einen Arbeitsanschluß an eine zum Tank 5 führenden Entlastungslei¬ tung 21 auf, in die eine Leckölleitung 22 der jeweiligen Verstellpumpe 1 bzw. 2 einmündet. In de in der Fig. 1 gezeigten Ausgangsstellung ist der Arbeitsanschluß an den Stelldruckleitungsabschnitt 19 gesperrt, während die verbleibenden Arbeitsanschlüsse offen sind. Von jedem Stelldruckleitungsab¬ schnitt 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 Stelldrucklei¬ tungsabschnitt 20 und die Entlastungsleitung 21 offen und der verbleibende Arbeitsanschluß gesperrt ist.One control valve 18 each is arranged in the actuating pressure lines 14 and divides them into a respective actuating pressure line section 19, 20 leading to the respective working line 3 or to the respective actuating cylinder 7. each Control valve 18 is designed as a continuously adjustable 3/2-way valve and has two working connections to the actuating pressure line sections 19 and 20 as well as a working connection to a discharge line 21 leading to the tank 5, into which a leak oil line 22 of the respective variable pump 1 or 2 flows. In the starting position shown in FIG. 1, the working connection to the signal pressure line section 19 is blocked, while the remaining working connections are open. A control pressure line 23 leads from each signal pressure line section 19 to a control connection of the associated control valve 18 and enables its adjustment in the direction of an end position in which the work connections to the signal pressure line section 20 and the relief line 21 are 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-Ein- stelleinrichtung 27.The device for total power control of the two variable displacement pumps 1, 2 comprises two electrical control elements 24, two measuring value transmitters 25, an electronic control unit 26 and a setpoint adjustment device 27 associated therewith.
Die elektrischen AnSteuerelemente 24 sind als kraftgeregelte Proporti- onalmagnete ausgebildet und je einem der Regelventile 18 zwecks Erzeugung eines dem Steuerdruck entgegenwirkenden Gegendrucks zugeordnet. Sie sind über j? eine Steuersignalleitung 28 mit der elektronischen Steuereinheit 26 verbunden.The electrical control elements 24 are designed as force-controlled proportional magnets and are each assigned to one of the control valves 18 for the purpose of generating a counter pressure counteracting the control pressure. Are you over j? a control signal line 28 is connected to the electronic control unit 26.
Die Meßwertgeber 25 sind als induktive Wegaufnehmer 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 inductive displacement transducers, which are assigned to the piston rod 10 of the respective actuating cylinder 7 for the purpose of detecting the respectively set delivery volume of the variable pumps 1, 2 and are connected to the electronic control unit 26 via a signal line 29.
Die elektroni sche Steuereinheit 26 i st al s Mikrocomputer ausgebi ldet, i n dessen Speichertei l di e i n Fi g. 2 gezei gte Kennl i nie KL gespeichert i st . Obwohl diese Kennl i ni e den Arbeitsdruck p i n Abhängigkeit vom Fördervol umen V einer Verstel l pumpe darstel lt, i st sie nachstehend aufgrund i hres für die Drehmomenten- bzw. Lei stungsregel ung typi schen Verl aufs al s Drehmomenten- 1 Kennlinie bezeichnet. Im vorliegenden Ausführungsbeispiel sind beideThe electronic control unit 26 is designed as a microcomputer, in the memory part of which a fi g. 2 shown maps are never stored in KL. Although this characteristic curve represents the working pressure pin as a function of the delivery volume V of an adjusting pump, it is based below on the torque and power regulation typical for the torque and power regulation. 1 characteristic curve. Both are in the present embodiment
Verstellpumpen 1, 2 und damit ihre Drehmomenten-Kennlinien identisch, so daßVariable pumps 1, 2 and thus their torque characteristics identical, so that
. lediglich eine dieser Kennlinien im Speicherteil des Mikrocomputers 26' gespeichert ist. 5, only one of these characteristics is stored in the memory part of the microcomputer 26 ' . 5
Die Fläche pxV unter der Drehmomenten-Kennlinie KL ist für jedes Fördervo¬ lumen V bzw. für jeden Arbeitsdruck p konstant und im vorliegenden Ausführungsbeispiel gleich dem Gesamtantriebsmoment des Antriebsmotors 6. Der Punkt P auf der Drehmomenten-Kennlinie KL kennzeichnet den Übergang vomThe area pxV below the torque characteristic curve KL 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 denotes the transition from
* sog. Anfahrbereich (senkrechter Abschnitt von KL ) zum Regelbereich (hyperbolischer Abschnitt von KL ), 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* So-called approach area (vertical section of KL) to the control area (hyperbolic section of KL), and its ordinate value corresponds to the setpoint value of the back pressure at the control valve 18, which is assigned to the variable pump 1 or 2 that transmits or is to transmit the total drive torque . The ordinate value of point P thus corresponds to that
15 maximalen Drehmoment, das diese Verstellpumpe übertragen kann, d.h. im vorliegenden Fall dem Gesamtantriebsmoment des Antriebsmotors 6. Der Sollwert des Gegendrucks an dem der jeweils anderen Verstellpumpe zugeordne¬ ten Regelventil ist auf Null eingestellt, um zu verhindern, daß diese Verstellpumpe durch Antrieb des an sie angeschlossenen Verbrauchers den 15 maximum torque that this variable pump can transmit, ie in the present case the total drive torque of the drive motor 6. The setpoint of the counter pressure at the control valve assigned to the other variable pump is set to zero in order to prevent this variable pump from being driven by the they connected the consumer
20 Antriebsmotor 6 überlastet.20 Drive motor 6 overloaded.
Die Sollwertsumme dieser beiden Gegendruck-Sollwerte und damit die Summe der Drehmomente beider Verstellpumpen 1, 2, die nicht größer als das Gesamtan¬ triebsmoment des Antriebsmotors 6 sein darf, ist ebenfalls im Speicherteil 25 des Mikrocomputers 26 gespeichert und kann mittels der Sollwert-EinstellVor¬ richtung in Sollwerte beliebiger Größe aufgeteilt werden.The setpoint sum of these two counterpressure setpoints and thus the sum of the torques of the two variable pumps 1, 2, which must not be greater than the total drive torque of the drive motor 6, is likewise stored in the memory part 25 of the microcomputer 26 and can be set by means of the setpoint setting device direction into target values of any size.
Die Funktion der erfindungsgemäßen Vorrichtung ist wie folgt:The function of the device according to the invention is as follows:
Beide durch die Druckfedern 16 auf maximales Fördervolumen eingestelltenBoth set to maximum delivery volume by the compression springs 16
30 Verstellpumpen 1, 2 werden durch den Antriebsmotor 6 mit gleicher Drehzahl angetrieben. Mit der Sollwert-EinstellVorrichtung 27 wird die im Mikrocompu¬ ter 26 gespeicherte, dem Gesamtantriebsmoment des Antriebsmotors 6 entspre¬ chende Sollwertsumme der Gegendruck-Sollwerte für beide Regelventile 18 entsprechend dem gewünschten Betriebsmodus aufgeteilt und somit jeder30 variable pumps 1, 2 are driven by the drive motor 6 at the same speed. With the setpoint value setting device 27, the setpoint sum of the counterpressure setpoints for both control valves 18, which is stored in the microcomputer 26 and corresponds to the total drive torque of the drive motor 6, is divided according to the desired operating mode and thus each
35 Verstellpumpe 1, 2 das maximale Drehmoment, das sie erzeugen kann, vorgegeben, beispielsweise für die Verstellpumpe 1 60% und für die Verstellpumpe 2 40% des Gesamtantriebsmomentes. Der Mikrocomputer 26 stellt für beide Verstellpumpen 1, 2 die den vorgegebenen Gegendruck-Sollwerten entsprechenden Drehmomenten-Kennlinien ein, d.h. diejenigen Kennlinien, deren Übergänge von ihren senkrechten Abschnitten zu ihren hyperbolischen Abschnitten durch die Punkte P, und P~ gekennzeichnet sind, deren Ordinatenwerte den vorgegebenen Gegendruck-Sollwerten entsprechen. Es ergeben sich somit im Fall der Verstellpumpe 1 die Kennlinie KL-, des dem Gegendruck-Sollwert von 60% der Sollwertsumme entsprechenden Drehmoments und im Falle der Verstellpumpe 2 die Kennlinie KL des dem Gegendruck-Sollwert von 40% der Sollwertsumme entsprechenden Drehmoments. Der Mikrocomputer 26 nimmt die Einstellung der den vorgegebenen Gegendruck-Sollwerten entspre¬ chenden Kennlinien KL im hier beschriebenen Ausführungsbeispiel durch Absenken des hyperbolischen Abschnitts von KL bis zu den Punkten P,, P? vor; es sind jedoch auch andere Möglichkeiten denkbar, wie etwa das Auswählen aus einer gespeicherten Kennlinienschar, die sämtliche, den möglichen ' Aufteilungen der Sollwertsumme entsprechende Kennlinien umfaßt. Der Mikrocomputer 26 verarbeitet nun jeden dieser beiden vorgegebenen Sollwerte zu einem entsprechenden Steuersignal und gibt dieses an den Proportionalmagneten 24 des jeweils zugeordneten Regelventils 18 aus, der einen entsprechenden Gegendruck erzeugt.35 variable pump 1, 2 the maximum torque that it can generate specified, for example for variable pump 1 60% and for variable pump 2 40% of the total drive torque. The microcomputer 26 sets for both variable displacement pumps 1, 2 the torque characteristic curves corresponding to the predetermined back pressure setpoints, ie those characteristic curves whose transitions from their vertical sections to their hyperbolic sections are identified by the points P, and P ~, the ordinate values of which correspond to the specified back pressure setpoints. This results in the case of the variable displacement pump 1, the characteristic curve KL-, the torque corresponding to the back pressure setpoint of 60% of the setpoint total and in the case of the variable displacement pump 2, the characteristic curve KL of the torque corresponding to the backpressure setpoint of 40% of the setpoint total. The microcomputer 26 takes the setting of the characteristic curves KL corresponding to the predetermined back pressure setpoints in the exemplary embodiment described here by lowering the hyperbolic section from KL to the points P ,, P ? in front; However, there are other possibilities are conceivable, such as selecting from a stored family of characteristics that all the possible 'splits the target value sum of respective characteristics comprises. The microcomputer 26 now processes each of these two predetermined setpoints into a corresponding control signal and outputs this to the proportional magnet 24 of the respectively associated control valve 18, which generates a corresponding counter pressure.
Solange die von den Arbeitsdrücken in den Arbeitsleitungen 3 abgenommenen Steuerdrücke kleiner als die an den Regelventilen eingestellten Gegendruck- Sollwerte sind, bleiben die Regelventile 18 in ihrer Ausgangsstellung und damit die Verstellpumpen 1, 2 auf maximales Fördervolumen eingestellt. Sobald die Steuerdrücke gleich den eingestellten Gegendruck-Sollwerten sind, belasten beide Verstellpumpen 1, 2 den Antriebsmotor 6 mit dem maximalen Drehmoment, auf das sie eingestellt sind und auf diese Weise gemeinsam mit dem Gesamtantriebsmoment, das der Antriebsmotor 6 aufbringt.As long as the control pressures taken from the working pressures in the working lines 3 are lower than the back pressure setpoints set on the control valves, the control valves 18 remain in their starting position and thus the variable pumps 1, 2 are set to the maximum delivery volume. As soon as the control pressures are equal to the set back pressure setpoints, both variable pumps 1, 2 load the drive motor 6 with the maximum torque to which they are set and in this way together with the total drive torque that the drive motor 6 applies.
Überschreiten die Steuerdrücke die eingestellten Gegendrücke, so spricht das jeweilige Regelventil 18 entsprechend dem Steuerdruck an und regelt dieIf the control pressures exceed the set back pressures, the respective control valve 18 responds according to the control pressure and regulates it
Stell druckbeauf schlagung der zugeordneten Stelleinrichtung in Richtung Verringerung des Fördervolumens der zugeordneten Verstellpumpe entlang dem hyperbolischen Abschnitt der jeweiligen Drehmomenten-Kennlinie KL, bzw. KL?. Dabei erfassen die Meßwertgeber 25 die jeweilige Stellung der Stellkolben 9 der Stellzylinder 7 und damit das Fördervolumen der jeweils zugeordneten Verstellpumpe 1 bzw. 2 und erzeugen entsprechende Signale. Die elektronische Steuereinheit 26 nimmt diese Signale auf und ermittelt daraus für jede Verstellpumpe 1, 2 denjenigen Arbeitsdruck p, der auf der zugeordneten Drehmomenten-Kennlinie KL, bzw. L dem vom jeweiligen Meßwertgeber 25 erfaßten Fördervolumen V entspricht. Dieser Arbeitsdruck p wird im Mikrocomputer 26 zu einem entsprechenden Steuersignal verarbeitet und an den jeweils zugeordneten Proportionalmagneten 24 zur Erzeugung eines entspre¬ chend höheren Gegendrucks am jeweiligen Regel ventil 18 ausgegeben. Auf diese Weise werden beide Verstellpumpen 1, 2 sowohl einzeln als auch gemeinsam mit Zunahme des von ihnen erzeugten Arbeitsdrucks so auf kleineres Fördervolumen zurückgeschwenkt, daß die den eingestellten Gegendruck-Sollwerten entspre- chenden Einzel antriebsdrehmomente bzw. das der Sollwertsumme entsprechende Gesamtantriebsdrehmoment nicht überschritten wird.Set pressurization of the associated actuating device in the direction of reducing the delivery volume of the associated variable displacement pump along the hyperbolic section of the respective torque characteristic curve KL or KL ? , The sensors 25 record the respective position of the actuating pistons 9 of the actuating cylinders 7 and thus the delivery volume of the respectively assigned variable displacement pumps 1 and 2 and generate corresponding signals. The electronic control unit 26 picks up these signals and uses them to determine for each variable pump 1, 2 that working pressure p which corresponds to the delivery volume V detected by the respective transducer 25 on the associated torque characteristic curve KL or L. This working pressure p is processed in the microcomputer 26 to produce a corresponding control signal and is output to the respectively associated proportional magnet 24 to generate a correspondingly higher back pressure at the respective control valve 18. In this way, both variable pumps 1, 2 are pivoted back both individually and together with an increase in the working pressure generated by them to a smaller delivery volume so that the individual drive torques corresponding to the set back pressure setpoints or the total drive torque corresponding to the setpoint total is not exceeded.
Selbstverständlich kann die im Speicherteil des Mikrocomputers 26 gespei¬ cherte Sollwertsumme mit der Sollwert-Einstellvorrichtung 27 auch auf andere als die vorstehend erwähnten Einzelsollwerte aufgeteilt werden, so daß es beispielsweise möglich ist, die Verstellpumpe 1 auf 100 % des Gesamtan¬ triebsdrehmomentes, beispielsweise zum Antrieb des Fahrwerks, und dement¬ sprechend die Verstellpumpe 2 auf null Prozent Gesamtantriebsdrehmoment einzustellen. Für den Fall, daß lediglich der Schwenkwerksmotor angetrieben werden soll, wird die Verstellpumpe 2 auf 100 % und die Verstellpumpe 1 dementsprechend auf null Prozent Gesamtantriebsdrehmoment eingestellt.Of course, the setpoint sum stored in the memory part of the microcomputer 26 can also be divided with the setpoint setting device 27 into individual setpoints other than those mentioned above, so that it is possible, for example, to adjust the variable pump 1 to 100% of the total drive torque, for example for driving of the undercarriage, and accordingly to adjust the variable displacement pump 2 to zero percent total drive torque. In the event that only the swivel mechanism motor is to be driven, the variable pump 2 is set to 100% and the variable pump 1 accordingly to zero percent total drive torque.
In einer alternativen Ausführung kann den Proportionalmagneten je eine Druckfeder zugeordnet sein, so daß der Gegendruck an jedem Regelventil 18 aus der Kraft des Proporcionalmagneten und der Einstellkraft dieser Druckfeder resultiert. Die Einstellkraft jeder dieser Druckfedern kann dabei der Sollwertsumme όer Gegendruck-Sollwerte entsprechen, und in diesem Fall weist jeder Proportionalmagnet entgegengesetzte Wirkrichtung auf, deren eine mit der Wirkrichtung des Steuerdrucks übereinstimmt, wenn dieser Steuerdruck kleiner als der Gegendruck und dessen eingestellter Sollwert kleiner als die Sollwertsumme ist, und deren anderer mit der Wirkrichtung der Druckfeder übereinstimmt, wenn der Steuerdruck- größer als der Gegendruck ist. In an alternative embodiment, the proportional magnets can each be assigned a compression spring, so that the back pressure at each control valve 18 results from the force of the proportional magnet and the adjusting force of this compression spring. The setting force of each of these compression springs can correspond to the setpoint sum ό of the counterpressure setpoints, and in this case each proportional magnet has an opposite direction of action, one of which corresponds to the direction of action of the control pressure if this control pressure is less than the counterpressure and its setpoint is less than the setpoint sum is, and the other coincides with the direction of action of the compression spring when the control pressure is greater than the back pressure.

Claims

PATENTANSPRÜCHE PATENT CLAIMS
1. Vorrichtung zur Summenleistungsregelung von wenigstens zwei durch einen gemeinsamen Antriebsmotor angetriebenen, in jeweils eine Arbeitsleitung fördernden hydrostatischen Verstellpumpen durch Verstellung ihres Förder¬ volumens mittels je einer mit einem Stelldruck beaufschlagbaren, in Richtung maximalen Fördervolumens vorgespannten Stelleinrichtung, mit je einem jeder Stelleinrichtung zugeordneten Regelventil, das von einem dem Arbeitsdruck in der Arbeitsleitung der durch die Stelleinrich¬ tung zu verstellenden Verstellpumpe entsprechenden Steuerdruck gegen einen Gegendruck beaufschlagt ist, wobei das Regelventil dann, wenn der Steuerdruck größer als der Gegendruck ist, anspricht und die Stelldruck- beaufschlεgung der Stelleinrichtung in Richtung einer Verringerung des Fördervolumens der Verstellpumpe so regelt, daß das Produkt aus Arbeitsdruck und Fördervolumen konstant ist, dadurch gekennzeichnet, daß1. Device for total power control of at least two hydrostatic variable displacement pumps driven by a common drive motor and each conveying to a working line by adjusting their delivery volume by means of an actuating device that can be biased with an actuating pressure and biased in the direction of maximum conveying volume, with a control valve assigned to each actuating device. the control pressure corresponding to the working pressure in the working line of the adjusting pump to be adjusted by the actuating device is acted against a counter pressure, the control valve responding when the control pressure is greater than the counter pressure and the actuating pressure acting on the actuating device in the direction of a Reduction of the delivery volume of the variable pump regulates so that the product of the working pressure and delivery volume is constant, characterized in that
- eine elektronische Steuereinheit (26) mit einem Speicherteil vorgesehen ist, in dem für die Verstellpumpen (1, 2) Kennlinien (KL) - Arbeitsdruck p in Abhängigkeit vom Fördervolumen V - konstanten Drehmoments sowie die Sollwertsumme von Sollwerten der an den Regelventilen (18) wirkenden Gegendrücke gespeichert sind,- An electronic control unit (26) with a memory part is provided, in which for the variable pumps (1, 2) characteristic curves (KL) - working pressure p as a function of the delivery volume V - constant torque and the setpoint sum of setpoints of the control valves (18) acting back pressures are stored,
- daß die elektronische Steuereinheit (26) eine Sollwert-Einstell- - That the electronic control unit (26) a setpoint adjustment
1 einrichtung (27) zum Aufteilen der Sollwertsumme in jeder Verstellpumpe zugeordnete Sollwerte beliebiger Größe aufweist, entsprechend den auf diese Weise vorgegebenen Gegendruck-Sollwerten die jeweils zugeordnete Kennlinie (KL,, KL-)) einstellt, jeden dieser vorgegebenen Sollwerte zu 1 device (27) for dividing the setpoint sum in each variable pump has assigned setpoints of any size, in accordance with the counterpressure setpoints specified in this way, sets the respectively assigned characteristic curve (KL ,, KL-) to each of these setpoints
^ einem entsprechenden Steuersignal verarbeitet und dieses Steuersignal an das zugeordnete elektrische Ansteuerelement (24) zur Erzeugung eines entsprechenden Gegendrucks am Regelventil (18) ausgibt,^ processes a corresponding control signal and outputs this control signal to the associated electrical control element (24) to generate a corresponding back pressure at the control valve (18),
- daß die elektronische Steuereinheit (26) an Meßwertgeber (25) angeschlossen ist, die die jeweils eingestellten Fördervolumina der Verstellpumpen (1, 2) erfassen, und- That the electronic control unit (26) is connected to transducers (25) which detect the respectively set delivery volumes of the variable pumps (1, 2), and
- daß die elektronische Steuereinheit (26) beim Ansprechen jedes Regelventils (18) denjenigen Arbeitsdruck (p) ermittelt, der auf der eingestellten Kennlinie (KL-,, KLp) der jeweiligen Verstellpumpe (1 bzw. 2) dem vom zugeordneten Meßwertgeber (25) erfaßten Fördervolumen (V) entspricht, diesen Arbeitsdruck (p) zu einem entsprechenden Steuersignal verarbeitet und dieses Steuersignal an das zugeordnete Ansteuerelement (24) zur Erzeugung eines entsprechenden Gegendrucks am Regelventil (18) ausgibt.- That the electronic control unit (26), when each control valve (18) responds, determines that working pressure (p) which, on the set characteristic curve (KL-, KLp) of the respective variable displacement pump (1 or 2), is assigned to the associated sensor (25) corresponds to the detected delivery volume (V), processes this working pressure (p) into a corresponding control signal and outputs this control signal to the assigned control element (24) to generate a corresponding back pressure at the control valve (18).
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die elektronische Steuereinheit (26) als Mikrocomputer ausgebildet ist.2. Device according to claim 1, characterized in that the electronic control unit (26) is designed as a microcomputer.
3. Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Meßwertgeber (25) induktive Wegaufnehmer sind, die die jeweilige Stellung der Stelleinrichtungen (4, 7) erfassen.3. Apparatus according to claim 1 or 2, characterized in that the sensors (25) are inductive displacement sensors which detect the respective position of the actuating devices (4, 7).
4. Vorrichtung nach wenigstens einem vorhergehenden Anspruch, dadurch gekennzeichnet, daß die elektrischen AnSteuerelemente (24) kraftgeregelte Proporti¬ onalmagnete sind. 4. The device according to at least one preceding claim, characterized in that the electrical control elements (24) are force-controlled proportional magnets.
EP95908254A 1994-02-18 1995-02-02 Device for regulating the total output of at least two hydrostatic variable displacement pumps Expired - Lifetime EP0745189B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4405234A DE4405234C1 (en) 1994-02-18 1994-02-18 Arrangement for the cumulative power regulation of at least two hydrostatic variable-displacement pumps
DE4405234 1994-02-18
PCT/EP1995/000382 WO1995022694A1 (en) 1994-02-18 1995-02-02 Device for regulating the total output of at least two hydrostatic variable displacement pumps

Publications (2)

Publication Number Publication Date
EP0745189A1 true EP0745189A1 (en) 1996-12-04
EP0745189B1 EP0745189B1 (en) 1997-12-29

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EP95908254A Expired - Lifetime EP0745189B1 (en) 1994-02-18 1995-02-02 Device for regulating the total output of at least two hydrostatic variable displacement pumps

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US (1) US5913663A (en)
EP (1) EP0745189B1 (en)
JP (1) JPH09508951A (en)
DE (2) DE4405234C1 (en)
WO (1) WO1995022694A1 (en)

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Also Published As

Publication number Publication date
EP0745189B1 (en) 1997-12-29
DE4405234C1 (en) 1995-04-06
JPH09508951A (en) 1997-09-09
US5913663A (en) 1999-06-22
DE59501169D1 (en) 1998-02-05
WO1995022694A1 (en) 1995-08-24

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