EP0043459B1 - Control device for a set of several pumps driven by a common energy source - Google Patents

Control device for a set of several pumps driven by a common energy source Download PDF

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Publication number
EP0043459B1
EP0043459B1 EP81104452A EP81104452A EP0043459B1 EP 0043459 B1 EP0043459 B1 EP 0043459B1 EP 81104452 A EP81104452 A EP 81104452A EP 81104452 A EP81104452 A EP 81104452A EP 0043459 B1 EP0043459 B1 EP 0043459B1
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EP
European Patent Office
Prior art keywords
pressure
control
line
valve
pump
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Expired
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EP81104452A
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German (de)
French (fr)
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EP0043459A2 (en
EP0043459A3 (en
Inventor
Dietrich Kuchenbecker
Erich Eckhardt
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Linde GmbH
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Linde GmbH
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Publication of EP0043459A3 publication Critical patent/EP0043459A3/en
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    • 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
    • F04B49/002—Hydraulic systems to change the pump delivery

Definitions

  • the invention relates to a control device for a unit comprising a plurality of pumps driven by a common primary energy source, of which at least one can be adjusted in terms of its stroke volume per revolution, the actuator of which is connected to an actuating piston which, in an actuating cylinder, increases the control pressure of the pump to a smaller stroke volume is adjustable, the control device also being provided with a control pressure auxiliary pump which is constant with respect to the delivery volume per revolution and driven by the same primary energy source and in the delivery capacity of which a throttle point is arranged, the pressure gradient upstream and downstream of this throttle point acting on the control pressure spaces of a hydraulically controlled drain valve, that is connected to a discharge line connected to the delivery line of the auxiliary control pump, an adjustable pressure valve also being provided, the setting of which depends on the sum of the delivery pressures d it is dependent on the pumps driven by the primary energy source, the flow of which is fed to the actual utility application.
  • the delivery line of the auxiliary control pressure pump branches behind the throttle point into the discharge line, which leads to the discharge valve, and a second line, which leads to the pressure valve, which is closed when the total delivery pressure of the pumps is below a limit value and throttling opens with increasing pressure, the throttling effect being reduced with increasing pressure in the delivery lines of the pumps.
  • Both the line emanating from the drain valve and the line emanating from the pressure valve are each connected to an input side of a pressure-dependent changeover valve, the output line of which is connected to the setting elements of the adjustable pump such that the higher of the two pressures, on the one hand, in the Drain line of the drain valve prevail and on the other hand prevail in the drain line of the pressure valve, which acts on the setting elements of the pump (US-A-3 841 795).
  • This device has the disadvantage that there is an unfavorable control characteristic, in particular pressure surges act on the setting members at the time of switching of the switching valve.
  • the discharge line leading to the discharge valve is connected to the delivery line of the control pressure auxiliary pump upstream of the throttle point and the control pressure line is connected, which leads to a cylinder in which a piston is displaceable, which is against a spring is supported, which is supported on the other hand against a mechanical link, act on the control piston parallel to said spring, each of which control piston is acted upon by the delivery pressure of a pump and is supported against a spring, this link being connected to the setting members of the individual adjustable pumps ist (DE-A-26 03 563 and Hydraulic, Pneumatic, Mechanical Power Band 23, No. 271, July 1977, pages 257-261, AT Clements “Power economy with hydrostatic transmission” see page 261, Fig. 6)
  • Known device is the "total power control" known per se by a speed reduction control overlaid. The mechanical part of the total power control is relatively complex here.
  • the invention has for its object to improve the control function of such a device and in particular to avoid discontinuities and vibrations.
  • the pressure valve is a pressure relief valve, which increases the pressure in the line leading to the pressure relief valve to a greater pressure as the sum of the pressures in the delivery lines of the pumps increases, this pressure relief valve in that of the Drain valve outgoing drain line is arranged and thus connected in series therewith, the drain line is further connected in the flow direction upstream of the throttle point to the control pump main line of the auxiliary control pressure pump and the control pressure line to which the setting elements of the adjustable pumps are connected is connected upstream of the drain valve.
  • the pressure in the control pressure line can act directly on the pistons connected to the actuator of a pump or can act indirectly on the actuators by the pressure acting on a control piston which controls the pressurization of the piston connected to an actuator of a pump.
  • control pistons which act on the pressure relief valve and which are displaceable in a control cylinder acted upon by the delivery pressure of the associated pump are supported against a control plate which is supported against a high pressure spring and which acts on the adjusting member of the pressure relief valve.
  • the discharge valve and the pressure relief valve are expediently arranged in a common block with the control pistons that control its setting.
  • the primary energy source is the diesel engine 1, which drives the adjustable pumps 6 and 7 and the pump 8, which is not adjustable in terms of its displacement volume per revolution, via the shaft 2 and the gear train 3, 4, 5.
  • the pump 6 delivers into the delivery line 9 and the pump 7 delivers into the delivery line 10. Both pumps 6 and 7 draw in from the pressureless container 11.
  • the pump 8 is connected in a closed circuit to the hydraulic motor 14 via the lines 12 and 13. Parts 2 to 14 are part of the main drive unit.
  • the diesel engine 1 also drives the auxiliary auxiliary pressure pump 16 via a secondary shaft 15, which also draws in from the container 11 and whose flow rate per revolution cannot be changed.
  • the auxiliary control pressure pump 16 feeds into the main control pump line 17, which is secured by a pressure relief valve 18 against impermissibly high pressure.
  • a throttle point 20 is arranged, which has the task of building up a pressure in the main control pressure pump line 17 dependent on the flow rate of the auxiliary control pressure pump 16 upstream of this throttle point 20.
  • this throttle point 20 has the task of causing a pressure gradient which is dependent on the drive speed of the control pressure auxiliary pump 16 and thus on the speed of the primary energy source 1 to be generated.
  • a discharge line 27 is connected to the control pump main line 17 at a point in the flow direction upstream of the throttle point 20 at a connection point 26, in which a constant throttle point 28 is arranged and which leads to the drain valve 24. From this drain line 27 branches off the control pressure line 29 which leads to the actuating cylinders 30 and 31 of the pumps 6 and 7, wherein an actuating piston can be displaced in each of the actuating cylinders 30 and 31 and is connected to the actuator of the respectively assigned pump 6 and 7 is.
  • the line 51 emanating from the drain valve 24 leads to the pressure limiting valve 37, the setting value of which is determined by the pretension of the low-pressure spring 38, which in turn is supported against a spring plate 41, which is rigidly connected via a plunger 42 to the control plate 43, against which support the control pressure pistons 44 and 45 and which is supported on the other hand against the high pressure spring 48.
  • the control pressure piston 44 is acted upon via line 46 by the pressure prevailing in the delivery line 9 of the pump 6 and the control pressure piston 45 is acted upon by the pressure prevailing in this delivery line 10 via line 47, which is connected to the delivery line 10 of the pump 7 .
  • the throttle point 20, the relief valve 24 and the pressure relief valve 37 with the associated control members, control pistons 44 and 45 and springs 48 and 38 are arranged in a common block 52.
  • the mode of operation is as follows: If the pressure drop at the throttle point 20, i.e. between the connection points 21 and 22, is large enough to overcome the actuating force at the drain valve 24, this remains open, so that the one acting in the main control pressure line 17 upstream of the throttle point 20 Pressure also acts before the throttle point 28. The current flowing through this flows through the discharge line 27 and the opened discharge valve 24 into the line 51 and from there to the pressure relief valve 37.
  • the pressure relief valve 37 When a pressure acts on the control pistons 44 and 45, the sum of which is less than the sum of the pressures, that are required to compress the high pressure spring 48, the pressure relief valve 37 remains open and the pressure medium flows from the line 51 to the container 11 without pressure, so that the line 51 and thus also the drain line 27 and thus also the control pressure line 29 are depressurized.
  • the pressure limiting valve 37 is set to a higher pressure as a result of an increase in the sum of the pressures in the delivery lines 9 and 10 and thus in the lines 46 and 47, the pressure in the line 51 thus increases, which increases through the discharge valve 24 the drain line 27 and thus affects the control pressure line 29, so that this higher pressure also acts on the actuating cylinders 30 and 31.
  • the discharge valve 24 closes as a result of this lower pressure gradient and first determines the congestion in front of the discharge valve 24 and thus in the discharge line 27 and thus in the control pressure line 29 also through its throttling and finally through its closed position with the result that the increasing pressure in the control pressure line 29 acts on the actuating cylinders 30 and 31 and thus sets the pumps 6 and 7 to a smaller delivery volume per revolution.
  • the discharge valve 24 opens again, so that pressure medium can flow out of the discharge line 27 and since the afterflow from the main control pressure line 17 is hindered by the throttle point 28 , the pressure in the discharge line 27 and thus in the control pressure line 29 drops again.
  • the throttling effect in the discharge valve 24 determines the pressure drop between the discharge line 27 and the line 51. If, at the beginning of the closing of the discharge valve 24, there was already an increased pressure in the line 51 as a result of the setting of the pressure relief valve 37, the pressure drop in the discharge valve 24 also causes the pressure in the discharge line 27 and thus the control pressure line 29 is influenced and increased accordingly, so that a superimposition effect occurs which, however, proceeds completely continuously without vibrations. Conversely, the same applies mutatis mutandis: if the drain valve 24 is in a throttling position and the pressure limiting valve 37 then begins to throttle, the pressure rising in the line 51 also has an effect on the drain line 27 upstream of the drain valve 24.
  • the control pump main line 17 is connected via a connection part 61 in such a way that it leads to a space 62 in the part 73 of the overall housing 52.
  • a component 60 is arranged in this space 62, which contains a baffle plate, which prevents the flow flowing axially through the line 17 from exerting a dynamic effect on the control piston 56.
  • a secondary bore 63 is connected to the space 62, in which a part 54 is arranged, which has a bore, which represents the throttle point 20, behind which the drain line 55 branches off, to the other consumers of low pressure, not shown and not dealt with further leads.
  • a component 58 is screwed into the control piston 56 and contains a narrower bore, which forms the throttle point 28.
  • the control piston 56 is supported against a spring 57 which holds the control piston 56 in its closed position when the pressure drop between the pressure in the space 62 and the pressure in the line 25 is too small. If the pressure drop is sufficient, the control piston 56 in FIG. 3 is displaced upwards so far that the control cone part 65 lies in front of the mouth of the line 27. In its most upwardly displaced position, the control piston 56 bears against the support screw 66, so that the transverse bores 67 in the control piston 56 lie in front of the mouths of the line 27. This is the normal operating situation.
  • the control piston 53 of the pressure relief valve is supported against the low pressure spring 38, which is supported on the other hand against the intermediate plate 43, against which the control pistons 44 and 45 are supported and which is connected to a pot-like part 68, on the flange on the left in the drawing, the high pressure spring 48 is supported.
  • the components in FIG. 3 with an upright axis thus form the drain valve 24, while the pressure relief valve 37 is shown with an axis lying horizontally.

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

Description

Die Erfindung betrifft eine Regeleinrichtung für ein Aggregat aus mehreren, von einer gemeinsamen Primärenergiequelle angetriebenen Pumpen von denen mindestens eine bezüglich ihres Hubvolumens pro Umdrehung einstellbar ist, wobei deren Stellglied mit einem Stellkolben verbunden ist, der in einem Stellzylinder bei zunehmendem Steuerdruck die Pumpe auf kleineres Hubvolumen einstellend verschiebbar ist, wobei die Regeleinrichtung ferner mit einer bezüglich des Fördervolumens pro Umdrehung konstanten, von der gleichen Primärenergiequelle angetriebenen Steuerdruckhilfspumpe versehen ist, in deren Förderleistung eine Drosselstelle angeordnet ist, wobei das Druckgefälle vor und hinter dieser Drosselstelle die Steuerdruckräume eines hydraulisch gesteuerten Ablassventils beaufschlagt, das an eine an die Förderleitung der Steuerhilfspumpe angeschlossenen Ablassleitung angeschlossen ist, wobei ferner ein einstellbares Druckventil vorgesehen ist, dessen Einstellage von der Summe der Förderdrücke der von der Primärenergiequelle angetriebenen Pumpen, deren Förderstrom der eigentlichen Nutzanwendung zugeführt wird, abhängig ist.The invention relates to a control device for a unit comprising a plurality of pumps driven by a common primary energy source, of which at least one can be adjusted in terms of its stroke volume per revolution, the actuator of which is connected to an actuating piston which, in an actuating cylinder, increases the control pressure of the pump to a smaller stroke volume is adjustable, the control device also being provided with a control pressure auxiliary pump which is constant with respect to the delivery volume per revolution and driven by the same primary energy source and in the delivery capacity of which a throttle point is arranged, the pressure gradient upstream and downstream of this throttle point acting on the control pressure spaces of a hydraulically controlled drain valve, that is connected to a discharge line connected to the delivery line of the auxiliary control pump, an adjustable pressure valve also being provided, the setting of which depends on the sum of the delivery pressures d it is dependent on the pumps driven by the primary energy source, the flow of which is fed to the actual utility application.

Bei einer bekannten Einrichtung dieser Art verzweigt sich die Förderleitung der Steuerdruckhilfspumpe hinter der Drosselstelle in die Ablassleitung, die zu dem Ablassventil führt, und eine zweite Leitung, die zu dem Druckventil führt, welches bei unterhalb eines Grenzwertes liegender Summe der Förderdrücke der Pumpen geschlossen ist und bei zunehmendem Druck drosselnd öffnet, wobei die Drosselwirkung mit zunehmendem Druck in den Förderleitungen der Pumpen verringert wird. Sowohl die von dem Ablassventil ausgehende Leitung als auch die von dem Druckventil ausgehende Leitung ist an je eine Eingangsseite eines druckabhängig umschaltenden Umschaltventiles angeschlossen, dessen Ausgangsleitung mit den Einstellorganen der einstellbaren Pumpe verbunden ist derart, dass der jeweils höhere der beiden Drücke, die einerseits in der Ablaufleitung des Ablassventiles herrschen und andererseits in der Ablaufleitung des Druckventiles herrschen, auf die Einstellorgane der Pumpe einwirkt (US-A-3 841 795). Diese Einrichtung hat den Nachteil, dass sich eine ungünstige Regelcharakteristik ergibt, insbesondere im Zeitpunkt des Umschaltens des Umschaltventiles Druckstösse auf die Einstellorgane wirken.In a known device of this type, the delivery line of the auxiliary control pressure pump branches behind the throttle point into the discharge line, which leads to the discharge valve, and a second line, which leads to the pressure valve, which is closed when the total delivery pressure of the pumps is below a limit value and throttling opens with increasing pressure, the throttling effect being reduced with increasing pressure in the delivery lines of the pumps. Both the line emanating from the drain valve and the line emanating from the pressure valve are each connected to an input side of a pressure-dependent changeover valve, the output line of which is connected to the setting elements of the adjustable pump such that the higher of the two pressures, on the one hand, in the Drain line of the drain valve prevail and on the other hand prevail in the drain line of the pressure valve, which acts on the setting elements of the pump (US-A-3 841 795). This device has the disadvantage that there is an unfavorable control characteristic, in particular pressure surges act on the setting members at the time of switching of the switching valve.

Bei einer anderen bekannten Regeleinrichtung für ein Aggregat der eingangs genannten Art ist an die Förderleitung der Steuerdruckhilfspumpe vor der Drosselstelle die zu dem Ablassventil führende Ablassleitung angeschlossen und die Steuerdruckleitung angeschlossen, die zu einem Zylinder führt, in dem eine Kolben verschiebbar ist, der gegen eine Feder abgestützt ist, die andererseits gegen ein mechanisches Glied abgestützt ist, auf das parallel zu der genannten Feder Steuerkolben einwirken, von denen jeder Steuerkolben vom Förderdruck einer Pumpe beaufschlagt ist und gegen eine Feder abgestützt ist, wobei dieses Glied mit den Einstellorganen der einzelnen einstellbaren Pumpen verbunden ist (DE-A-26 03 563 und Hydraulic, Pneumatic, Mechanical Power Band 23, Nr. 271, Juli 1977, Seiten 257-261, A. T. Clements «Power economy with hydrostatic transmission» siehe Seite 261, Fig. 6) Bei dieser bekannten Einrichtung wird die an sich bekannte «Summenleistungsregelung» durch eine Drehzahldrückungssteuerung überlagert. Hier ist der mechanische Teil der Summenleistungsregelung relativ aufwendig.In another known control device for a unit of the type mentioned, the discharge line leading to the discharge valve is connected to the delivery line of the control pressure auxiliary pump upstream of the throttle point and the control pressure line is connected, which leads to a cylinder in which a piston is displaceable, which is against a spring is supported, which is supported on the other hand against a mechanical link, act on the control piston parallel to said spring, each of which control piston is acted upon by the delivery pressure of a pump and is supported against a spring, this link being connected to the setting members of the individual adjustable pumps ist (DE-A-26 03 563 and Hydraulic, Pneumatic, Mechanical Power Band 23, No. 271, July 1977, pages 257-261, AT Clements “Power economy with hydrostatic transmission” see page 261, Fig. 6) Known device is the "total power control" known per se by a speed reduction control overlaid. The mechanical part of the total power control is relatively complex here.

Der Erfindung liegt die Aufgabe zugrunde, die Regelfunktion einer solchen Einrichtung zu verbessern und insbesondere Unstetigkeiten und Schwingungen zu vermeiden.The invention has for its object to improve the control function of such a device and in particular to avoid discontinuities and vibrations.

Diese Aufgabe wird gemäss der vorliegenden Erfindung dadurch gelöst, dass das Druckventil ein Druckbegrenzungsventil ist, welches bei Zunehmen der Summe der Drücke in den Förderleitungen der Pumpen den Druck in der zum Druckbegrenzungsventil führenden Leitung auf einen grösseren Druck aufstaut, wobei dieses Druckbegrenzungsventil in der von dem Ablassventil ausgehenden Ablaufleitung angeordnet ist und somit mit diesem in Reihe geschaltet ist, wobei ferner die Ablassleitung in Strömungsrichtung vor der Drosselstelle an die Steuerpumpenhauptleitung der Steuerdruckhilfspumpe angeschlossen ist und die Steuerdruckleitung, an die die Einstellorgane der einstellbaren Pumpen angeschlossen sind, vor dem Ablassventil angeschlossen ist.This object is achieved according to the present invention in that the pressure valve is a pressure relief valve, which increases the pressure in the line leading to the pressure relief valve to a greater pressure as the sum of the pressures in the delivery lines of the pumps increases, this pressure relief valve in that of the Drain valve outgoing drain line is arranged and thus connected in series therewith, the drain line is further connected in the flow direction upstream of the throttle point to the control pump main line of the auxiliary control pressure pump and the control pressure line to which the setting elements of the adjustable pumps are connected is connected upstream of the drain valve.

Der Druck in der Steuerdruckleitung kann dabei unmittelbar auf die jeweilis mit dem Stellglied einer Pumpe verbundenen Kolben einwirken oder kann mittelbar auf die Stellglieder einwirken, indem der Druck auf einen Steuerkolben wirkt, der die Druckbeaufschlagung des jeweils mit einem Stellglied einer Pumpe verbundenen Kolbens steuert.The pressure in the control pressure line can act directly on the pistons connected to the actuator of a pump or can act indirectly on the actuators by the pressure acting on a control piston which controls the pressurization of the piston connected to an actuator of a pump.

In einer zweckmässigen Ausgestaltungsform ist vorgesehen, dass die auf das Druckbegrenzungsventil einwirkenden in jeweils einem vom Förderdruck der zugeordneten Pumpe beaufschlagten Steuerzylinder verschiebbaren Steuerkolben gegen eine gegen eine Hochdruckfeder abgestützte Steuerplatte abgestützt sind, die auf das Einstellorgan des Druckbegrenzungsventiles einwirkt.In an expedient embodiment, it is provided that the control pistons which act on the pressure relief valve and which are displaceable in a control cylinder acted upon by the delivery pressure of the associated pump are supported against a control plate which is supported against a high pressure spring and which acts on the adjusting member of the pressure relief valve.

Zweckmässigerweise sind das Ablassventil und das Druckbegrenzungsventil mit den dessen Einstellung steuernden Steuerkolben in einem gemeinsamen Block angeordnet.The discharge valve and the pressure relief valve are expediently arranged in a common block with the control pistons that control its setting.

Die Erfindung ist im weiteren anhand des in der Zeichnung dargestellten Ausführungsbeispieles erläutert.

  • Figur 1 zeigt ein Schaltschema der Regeleinrichtung
  • Figur 2 zeigt einen Schnitt durch eine Regeleinrichtung in einem Block.
The invention is explained below with reference to the embodiment shown in the drawing.
  • Figure 1 shows a circuit diagram of the control device
  • Figure 2 shows a section through a control device in a block.

Die Primärenergiequelle ist der Dieselmotor 1 der über die Welle 2 und das Zahnradvorgelege 3, 4,5 die einstellbaren Pumpen 6 und 7 und die bezüglich ihres Verdränungsvolumen pro Umdrehung nicht einstellbare Pumpe 8 antreibt.The primary energy source is the diesel engine 1, which drives the adjustable pumps 6 and 7 and the pump 8, which is not adjustable in terms of its displacement volume per revolution, via the shaft 2 and the gear train 3, 4, 5.

Die Pumpe 6 fördert in die Förderleitung 9 und die Pumpe 7 fördert in die Förderleitung 10. Beide Pumpen 6 und 7 saugen aus dem drucklosen Behälter 11 an. Die Pumpe 8 ist über die Leitungen 12 und 13 in geschlossenem Kreislauf mit dem Hydromotor 14 verbunden. Die Teile 2 bis 14 sind Teil des Hauptantriebsaggregates.The pump 6 delivers into the delivery line 9 and the pump 7 delivers into the delivery line 10. Both pumps 6 and 7 draw in from the pressureless container 11. The pump 8 is connected in a closed circuit to the hydraulic motor 14 via the lines 12 and 13. Parts 2 to 14 are part of the main drive unit.

Der Dieselmotor 1 treibt weiterhin über eine Nebenwelle 15 die Steuerdruckhilfspumpe 16 an, die ebenfalls aus dem Behälter 11 ansaugt und deren Förderstrom pro Umdrehung unveränderbar ist. Die Steuerdruckhilfspumpe 16 fördert in die Steuerpumpenhauptleitung 17, die durch ein Druckbegrenzungsventil 18 gegen unzulässig hohen Druck abgesichert ist. In der Steuerpumpenhauptleitung 17 ist eine Drosselstelle 20 angeordnet die die Aufgabe hat, einen vom Förderstrom der Steuerdruckhilfspumpe 16 abhängigen Druck in der Steuerdruckpumpenhauptleitung 17 vor dieser Drosselstelle 20 aufzustauen. Anders ausgedrückt, hat diese Drosselstelle 20 die Aufgabe, zu bewirken, dass ein von der Antriebsdrehzahl der Steuerdruckhilfspumpe 16 und damit von der Drehzahl der Primärenenergiequelle 1 abhängiges Druckgefälle erzeugt wird. Dieses Druckgefälle wird an den Anschlussstellen 21 und 22 abgenommen, wobei der Druck in der Steuerpumpenhauptleitung 17 vor der Drosselstelle 20 durch die Steuerdruckleitung 23 dem einen Steuerdruckraum des Ablassventiles 24 zugeführt wird und der Druck in der Steuerpumpenhaupt- . leitung 17 hinter der Drosselstelle 20 über die Leitung 25 dem anderen Steuerdruckraum des Ablassventiles 24 zugeführt wird. Bei grossem Druckgefälle zwischen den Abzweigstellen 21 und 22 ist das Ablassventil 24 geöffnet. Hingegen bei unter einen vorbestimmten Grenzwert absinkendem Druckgefälle schliesst das Ablassventil 24 zunächst drosselnd ab.The diesel engine 1 also drives the auxiliary auxiliary pressure pump 16 via a secondary shaft 15, which also draws in from the container 11 and whose flow rate per revolution cannot be changed. The auxiliary control pressure pump 16 feeds into the main control pump line 17, which is secured by a pressure relief valve 18 against impermissibly high pressure. In the main control pump line 17, a throttle point 20 is arranged, which has the task of building up a pressure in the main control pressure pump line 17 dependent on the flow rate of the auxiliary control pressure pump 16 upstream of this throttle point 20. In other words, this throttle point 20 has the task of causing a pressure gradient which is dependent on the drive speed of the control pressure auxiliary pump 16 and thus on the speed of the primary energy source 1 to be generated. This pressure drop is taken off at the connection points 21 and 22, the pressure in the main control pump line 17 upstream of the throttle point 20 being fed through the control pressure line 23 to the one control pressure chamber of the drain valve 24 and the pressure in the main control pump. line 17 is fed behind the throttle point 20 via line 25 to the other control pressure chamber of the drain valve 24. With a large pressure drop between the branch points 21 and 22, the drain valve 24 is open. In contrast, when the pressure drop drops below a predetermined limit value, the drain valve 24 initially closes in a throttling manner.

An die Steuerpumpenhauptleitung 17 ist an einer in Strömungsrichtung vor der Drosselstelle 20 liegenden Stelle an einer Anschlussstelle 26 eine Ablassleitung 27 angeschlossen, in der eine Konstantdrosselstelle 28 angeordnet ist und die zu dem Ablassventil 24 führt. Von dieser Ablassleitung 27 zweigt die Steuerdruckleitung 29 ab, die zu den Stellzylindern 30 und 31 der Pumpen 6 und 7 führt, wobei in jedem der Stellzylinder 30 und 31 ein Stellkolben verschiebbar ist, der mit dem Stellglied der jeweils zugeordneten Pumpe 6 bzw. 7 verbunden ist.A discharge line 27 is connected to the control pump main line 17 at a point in the flow direction upstream of the throttle point 20 at a connection point 26, in which a constant throttle point 28 is arranged and which leads to the drain valve 24. From this drain line 27 branches off the control pressure line 29 which leads to the actuating cylinders 30 and 31 of the pumps 6 and 7, wherein an actuating piston can be displaced in each of the actuating cylinders 30 and 31 and is connected to the actuator of the respectively assigned pump 6 and 7 is.

Die von dem Ablassventil 24 ausgehende Leitung 51 führt zu dem Druckbegrenzungsventil 37, dessen Einstellwert durch die Vorspannung der Niederdruckfeder 38 bestimmt ist, die ihrerseits gegen einen Federteller 41 abgestützt ist, der über einen Stempel 42 starr mit der Steuerplatte 43 verbunden ist, gegen die sich die Steuerdruckkolben 44 und 45 abstützen und die andererseits gegen die Hochdruckfeder 48 abgestützt ist. Der Steuerdruckkolben 44 wird über die Leitung 46 von dem in der Förderleitung 9 der Pumpe 6 herrschenden Druck beaufschlagt und der Steuerdruckkolben 45 wird über die Leitung 47, die an die Förderleitung 10 der Pumpe 7 angeschlossen ist, von dem in dieser Förderleitung 10 herrschenden Druck beaufschlagt.The line 51 emanating from the drain valve 24 leads to the pressure limiting valve 37, the setting value of which is determined by the pretension of the low-pressure spring 38, which in turn is supported against a spring plate 41, which is rigidly connected via a plunger 42 to the control plate 43, against which support the control pressure pistons 44 and 45 and which is supported on the other hand against the high pressure spring 48. The control pressure piston 44 is acted upon via line 46 by the pressure prevailing in the delivery line 9 of the pump 6 and the control pressure piston 45 is acted upon by the pressure prevailing in this delivery line 10 via line 47, which is connected to the delivery line 10 of the pump 7 .

Die Drosselstelle 20, das Ablassventil 24 und das Druckbegrenzungsventil 37 mit den zugehörigen Steuerorganen Steuerkolben 44 und 45 und Federn 48 und 38 sind in einem gemeinsamen Block 52 angeordnet.The throttle point 20, the relief valve 24 and the pressure relief valve 37 with the associated control members, control pistons 44 and 45 and springs 48 and 38 are arranged in a common block 52.

Die Wirkungsweise ist folgende: Wenn das Druckgefälle an der Drosselstelle 20, also zwischen den Anschlussstellen 21 und 22, gross genug ist, um die Stellkraft am Ablassventil 24 zu überwinden, bleibt dieses geöffnet, so dass der in der Steuerdruckhauptleitung 17 vor der Drosselstelle 20 wirkende Druck auch vor der Drosselstelle 28 wirkt. Der diese durchfliessende Strom fliesst durch die Ablassleitung 27 und das geöff= nete Ablassventil 24 in die Leitung 51 und von dieser zu dem Druckbegrenzungsventil 37. Wenn auf die Steuerkolben 44 und 45 jeweils ein Druck wirkt, dessen Summe kleiner ist als die Summe der Drücke, die erforderlich sind, die Hochdruckfeder 48 zusammenzudrücken, bleibt das Druckbegrenzungsventil 37 geöffnet und das Druckmittel fliesst aus der Leitung 51 drucklos zu dem Behälter 11 ab, so dass die Leitung 51 und damit auch die Ablassleitung 27 und damit auch die Steuerdruckleitung 29 drucklos sind. Wenn jedoch infolge eines Ansteigens der Summe der Drücke in den Förderleitungen 9 und 10 und damit in den Leitungen 46 und 47 das Druckbegrenzungsventil 37 auf einen höheren Druck eingestellt wird, steigt somit in der Leitung 51 der Druck an, der sich durch das Ablassventil 24 auf die Ablassleitung 27 und damit auf die Steuerdruckleitung 29 auswirkt, so dass dieser höhere Druck auch auf die Stellzylinder 30 und 31 wirkt.The mode of operation is as follows: If the pressure drop at the throttle point 20, i.e. between the connection points 21 and 22, is large enough to overcome the actuating force at the drain valve 24, this remains open, so that the one acting in the main control pressure line 17 upstream of the throttle point 20 Pressure also acts before the throttle point 28. The current flowing through this flows through the discharge line 27 and the opened discharge valve 24 into the line 51 and from there to the pressure relief valve 37. When a pressure acts on the control pistons 44 and 45, the sum of which is less than the sum of the pressures, that are required to compress the high pressure spring 48, the pressure relief valve 37 remains open and the pressure medium flows from the line 51 to the container 11 without pressure, so that the line 51 and thus also the drain line 27 and thus also the control pressure line 29 are depressurized. However, if the pressure limiting valve 37 is set to a higher pressure as a result of an increase in the sum of the pressures in the delivery lines 9 and 10 and thus in the lines 46 and 47, the pressure in the line 51 thus increases, which increases through the discharge valve 24 the drain line 27 and thus affects the control pressure line 29, so that this higher pressure also acts on the actuating cylinders 30 and 31.

Erreicht die Summe der in den Leitungen 46 und 47 anstehenden und damit auf die Steuerkolben 44 und 45 wirkenden Drücke nicht die Höhe des Grenzwertes, der erforderlich ist, um die Hochdruckfeder 48 zusammenzudrücken, sinkt jedoch das Druckgefälle zwischen den Anschlussstellen 21 und 22 infolge kleiner werdenden Förderstromes der Steuerdruckhilfspumpe 16 infolge eines Absinkens der Antriebsdrehzahl, so schliesst infolge dieses geringeren Druckgefälles das Ablassventil 24 und bestimmt zunächst durch seine Drosselung und schliesslich durch seine Schliessstellung den Stau vor dem Ablassventil 24 und damit in der Ablassleitung 27 und damit in der Steuerdruckleitung 29, ebenfalls mit der Folge, dass der steigende Druck in der Steuerdruckleitung 29 auf die Stellzylinder 30 und 31 einwirkt und damit die Pumpen 6 und 7 auf ein kleineres Fördervolumen pro Umdrehung einstellt. Steigt infolge eines steigenden Förderstromes der Steuerdruckhilfspumpe 16 das Druckgefälle zwischen den Anschlussstellen 21 und 22 wieder, so öffnet das Ablassventil 24 wieder, so dass durch dieses Druckmittel aus der Ablassleitung 27 abfliessen kann und da das Nachfliessen aus der Steuerdruckhauptleitung 17 durch die Drosselstelle 28 behindert wird, sinkt der Druck in der Ablassleitung 27 und damit in der Steuerdruckleitung 29 wieder.If the sum of the pressures present in the lines 46 and 47 and thus acting on the control pistons 44 and 45 does not reach the level of the limit value which is required to compress the high-pressure spring 48, the pressure drop between the connection points 21 and 22 decreases as a result of becoming smaller Delivery flow of the control pressure auxiliary pump 16 as a result of a drop in the drive speed, the discharge valve 24 closes as a result of this lower pressure gradient and first determines the congestion in front of the discharge valve 24 and thus in the discharge line 27 and thus in the control pressure line 29 also through its throttling and finally through its closed position with the result that the increasing pressure in the control pressure line 29 acts on the actuating cylinders 30 and 31 and thus sets the pumps 6 and 7 to a smaller delivery volume per revolution. If the pressure drop between the connection points 21 and 22 increases again as a result of an increasing delivery flow of the control pressure auxiliary pump 16, the discharge valve 24 opens again, so that pressure medium can flow out of the discharge line 27 and since the afterflow from the main control pressure line 17 is hindered by the throttle point 28 , the pressure in the discharge line 27 and thus in the control pressure line 29 drops again.

Die Drosselwirkung im Ablassventil 24 bestimmt das Druckgefälle zwischen der Ablassleitung 27 und der Leitung 51. Hat bei Beginn des Schliessens des Ablassventiles 24 bereits infolge der Einstellung des Druckbegrenzungsventils 37 ein erhöhter Druck in der Leitung 51 geherrscht, so wird durch das Druckgefälle im Ablassventil 24 auch der Druck in der Ablassleitung 27 und damit der Steuerdruckleitung 29 beeinflusst und entsprechend erhöht, so dass ein Überlagerungseffekt entsteht, der jedoch vollkommen stufenlos ohne Schwingungen abläuft. Umgekehrt gilt sinngemäss das Gleiche: Befindet sich das Ablassventil 24 in einer drosselnden Stellung und beginnt dann das Druckbegrenzungsventil 37 zu drosseln, so wirkt sich der in der Leitung 51 steigende Druck auch auf die Ablassleitung 27 vor dem Ablassventil 24 aus.The throttling effect in the discharge valve 24 determines the pressure drop between the discharge line 27 and the line 51. If, at the beginning of the closing of the discharge valve 24, there was already an increased pressure in the line 51 as a result of the setting of the pressure relief valve 37, the pressure drop in the discharge valve 24 also causes the pressure in the discharge line 27 and thus the control pressure line 29 is influenced and increased accordingly, so that a superimposition effect occurs which, however, proceeds completely continuously without vibrations. Conversely, the same applies mutatis mutandis: if the drain valve 24 is in a throttling position and the pressure limiting valve 37 then begins to throttle, the pressure rising in the line 51 also has an effect on the drain line 27 upstream of the drain valve 24.

In Figur 2 sind in einer Schnittdarstellung die in dem Block 52 enthaltenden Teile dargestellt.In Figure 2, the parts contained in block 52 are shown in a sectional view.

Die Steuerpumpenhauptleitung 17 ist über ein Anschlussteil 61 derart angeschlossen, dass sie zu einem Raum 62 in dem Teil 73 des Gesamtgehäuses 52 führt. In diesem Raum 62 ist ein Bauteil 60 angeordnet, welches eine Prallplatte enthält, die verhindert, dass die durch die Leitung 17 axial anströmende Strömung eine dynamische Wirkung auf den Regelkolben 56 ausübt. An den Raum 62 ist eine Nebenbohrung 63 angeschlossen, in dem ein Teil 54 angeordnet ist, welches eine Bohrung aufweist, welches die Drosselstelle 20 darstellt, hinter der die Ablaufleitung 55 abzweigt, die zu den nicht weiter dargestellten und nicht weiter behandelten weiteren Verbrauchern von Niederdruck führt.The control pump main line 17 is connected via a connection part 61 in such a way that it leads to a space 62 in the part 73 of the overall housing 52. A component 60 is arranged in this space 62, which contains a baffle plate, which prevents the flow flowing axially through the line 17 from exerting a dynamic effect on the control piston 56. A secondary bore 63 is connected to the space 62, in which a part 54 is arranged, which has a bore, which represents the throttle point 20, behind which the drain line 55 branches off, to the other consumers of low pressure, not shown and not dealt with further leads.

In den Regelkolben 56 ist ein Bauteil 58 eingeschraubt, das eine engere Bohrung enthält, welche die Drosselstelle 28 bildet. Der Regelkolben 56 ist gegen eine Feder 57 abgestützt, die den Regelkolben 56 in seiner Schliessstellung hält, wenn das Druckgefälle zwischen dem Druck in dem Raum 62 und dem Druck in der Leitung 25 zu gering ist. Reicht das Druckgefälle aus, ist der Regelkolben 56 in Figur 3 so weit nach oben verschoben, dass der Regelkegelteil 65 vor der Mündung der Leitung 27 liegt. In seiner am weitesten nach oben verschobenen Lage liegt der Regelkolben 56 gegen die Stützschraube 66 an, so dass die Querbohrungen 67 in dem Regelkolben 56 vor den Mündungen der Leitung 27 liegen. Das ist die Normalbetriebslage.A component 58 is screwed into the control piston 56 and contains a narrower bore, which forms the throttle point 28. The control piston 56 is supported against a spring 57 which holds the control piston 56 in its closed position when the pressure drop between the pressure in the space 62 and the pressure in the line 25 is too small. If the pressure drop is sufficient, the control piston 56 in FIG. 3 is displaced upwards so far that the control cone part 65 lies in front of the mouth of the line 27. In its most upwardly displaced position, the control piston 56 bears against the support screw 66, so that the transverse bores 67 in the control piston 56 lie in front of the mouths of the line 27. This is the normal operating situation.

Der Regelkolben 53 des Druckbegrenzungsventiles ist gegen die Niederdruckfeder 38 abgestützt, die andererseits gegen die Zwischenplatte 43 abgestützt ist, gegen die sich die Steuerkolben 44 und 45 abstützen und die mit einem topfartigen Teil 68 verbunden ist, an dessen in der Zeichnung linken Flansch die Hochdruckfeder 48 abgestützt ist. Die Bauteile in Figur 3 mit aufrechter Achse bilden somit das Ablassventil 24 während das Druckbegrenzungsventil 37 mit waagrecht liegender Achse abgebildet ist.The control piston 53 of the pressure relief valve is supported against the low pressure spring 38, which is supported on the other hand against the intermediate plate 43, against which the control pistons 44 and 45 are supported and which is connected to a pot-like part 68, on the flange on the left in the drawing, the high pressure spring 48 is supported. The components in FIG. 3 with an upright axis thus form the drain valve 24, while the pressure relief valve 37 is shown with an axis lying horizontally.

Claims (3)

1. A control device for an assembly consisting of a plurality of pumps (6, 7, 8) which are driven by a common primary energy source (1) and at least one of which as adjustable as regards its stroke volume per revolution, wherein the adjusting element thereof is connected to an adjusting piston which is displaceable in an adjusting cylinder (30, 31), which increasing control pressure, to adjust the pump to a smaller stroke volume per revolution, wherein the control device is furthermore provided with an auxiliary control pressure pump (16) which is driven by the same primary energy source (1), and is constant with regard to the volume conveyed per revolution, and in whose output line (17) a restriction (20) is arrang- . ed, wherein the pressure drop before and after the restriction (20) acts on the control pressure chambers of a hydraulically controlled discharge valve (24) which is inserted into a discharge line (27) connected to the output line (27) of the auxiliary control pressure pump (16), wherein furthermore an adjustable pressure valve (37) is provided, the adjusted position of which is dependent upon the sum of the output pressures of the pumps (6, 7, 8) which are driven by the primary energy source (1), characterised in that the pressure valve is a pressure limiting valve (37) which when the sum of the pressures in the conveyor lines (9, 10) of the pumps (6, 7) increases, builds up the pressure in the line (51), which leads to the pressure relief control valve (37), so as to reach a higher pressure, and that this pressure relief control valve is arranged in the outlet line (51) from the discharge valve (24) and is thus connected in series thereto; and that the discharge line (27) is connected to the main control pump line (17) of the auxiliary control pressure pump (16) upstream of the restriction (20) in the direction of flow; and that a control pressure line (29), to which all the adjusting elements (30, 31), of the adjustable pumps (6 and 7) are connected, branches from the discharge line (27) upstream of the discharge valve (24).
2. A control device according to Claim 1, characterised in that the control pistons (44, 45), which act on the pressure relief control valve (37) and are displaceable in a control cylinder, which is acted on by the output pressure of the assignea pump (6 or 7), are supported against a control plate, which is supported against a high pressure spring (48) and which acts on the adjusting element of the pressure relief control valve (37).
3. A control device according to Claim 1 or Claim 2, characterised in that the discharge valve (24) and the pressure control relief valve (37), together with the control cylinders, in which the control pistons (44 and 45) controlling the adjustment of the pressure relief control valve (37) are displaceable are arranged in a common block (52).
EP81104452A 1980-06-28 1981-06-10 Control device for a set of several pumps driven by a common energy source Expired EP0043459B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19803024399 DE3024399A1 (en) 1980-06-28 1980-06-28 CONTROL DEVICE FOR A UNIT COMPOSED OF SEVERAL PUMP DRIVEN BY A COMMON PRIMARY ENERGY SOURCE
DE3024399 1980-06-28

Publications (3)

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EP0043459A2 EP0043459A2 (en) 1982-01-13
EP0043459A3 EP0043459A3 (en) 1982-01-20
EP0043459B1 true EP0043459B1 (en) 1984-09-12

Family

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Application Number Title Priority Date Filing Date
EP81104452A Expired EP0043459B1 (en) 1980-06-28 1981-06-10 Control device for a set of several pumps driven by a common energy source

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US (1) US4405287A (en)
EP (1) EP0043459B1 (en)
JP (1) JPS5746082A (en)
BR (1) BR8104068A (en)
DE (1) DE3024399A1 (en)

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US4739616A (en) * 1985-12-13 1988-04-26 Sundstrand Corporation Summing pressure compensation control
JPH01220706A (en) * 1988-02-25 1989-09-04 Komatsu Ltd Hydraulic control device for hydraulic excavator
US4984427A (en) * 1989-09-01 1991-01-15 Kabushiki Kaisha Kobe Seiko Sho Control circuit for hydraulic actuator
US5600952A (en) * 1995-09-26 1997-02-11 Aurora Technology Corporation Auxilliary drive apparatus
JPH10141310A (en) * 1996-11-13 1998-05-26 Komatsu Ltd Pressure oil feeder
US8117837B1 (en) * 2003-12-17 2012-02-21 Sauer-Danfoss Inc. Hydrostatic transmission having integrated pressure compensated load sensing auxiliary pump
CN102305204A (en) * 2011-08-22 2012-01-04 广西玉柴重工有限公司 Rotating speed induction type variable constant flow pump
US11725647B2 (en) * 2021-05-18 2023-08-15 Hamilton Sundstrand Corporation On-demand dual variable displacement positive displacement pumping system

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Also Published As

Publication number Publication date
EP0043459A2 (en) 1982-01-13
US4405287A (en) 1983-09-20
EP0043459A3 (en) 1982-01-20
BR8104068A (en) 1982-03-16
JPS5746082A (en) 1982-03-16
DE3024399A1 (en) 1982-01-21

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