EP0884476B1 - Pressure limiting control circuit for the safe operation of a variable displacement radial or axial hydraulic piston pump or vane cell machine - Google Patents

Pressure limiting control circuit for the safe operation of a variable displacement radial or axial hydraulic piston pump or vane cell machine Download PDF

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Publication number
EP0884476B1
EP0884476B1 EP98105057A EP98105057A EP0884476B1 EP 0884476 B1 EP0884476 B1 EP 0884476B1 EP 98105057 A EP98105057 A EP 98105057A EP 98105057 A EP98105057 A EP 98105057A EP 0884476 B1 EP0884476 B1 EP 0884476B1
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EP
European Patent Office
Prior art keywords
pressure
working machine
valve
machine
adjustable hydraulic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP98105057A
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German (de)
French (fr)
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EP0884476A2 (en
EP0884476A3 (en
Inventor
Volkmar Leutner
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP0884476A3 publication Critical patent/EP0884476A3/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/10—Other safety measures
    • 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
    • F04B2205/00—Fluid parameters
    • F04B2205/06—Pressure in a (hydraulic) circuit
    • F04B2205/061—Pressure in a (hydraulic) circuit after a throttle

Definitions

  • the invention is based on an adjustable hydraulic Working machine according to the preamble of claim 1 out.
  • a machine in the form of a Radial piston pump is for example from DE-A-3 140 397 or DE 44 10 719.6 A1 is already known.
  • This radial piston pump is equipped with a number of sensors whose signals evaluated in a control unit and to a control signal be processed for an adjustment device that on the Radial piston pump lifting device acts. Aim this The arrangement is to run as quietly as possible To reach radial piston pump. If there is one Mishandling of the adjustment device, the Radial piston pump set to maximum flow become. In extreme cases, i.e. if the pressure supply of the Adjustment device not via the pump outlet but via If an external device is used, this can be done for vacuuming of the connected hydraulic system and then through Lack of lubricant to self-destruct the Guide the radial piston pump.
  • the work machine according to the invention has the characterizing features of claim 1 the advantage a switchable hydraulic safety device on the machine in the event of a fault in emergency operation switches.
  • the Machine regulated to a constant operating pressure, in which the self-destruction of the work machine is excluded.
  • the safety device can be opened relatively simple way in the control valve Integrate adjustment device and is proportionate simple and therefore inexpensive hydraulic components built up. The required components enlarge it Construction volume of the control valve is at most insignificant. Further advantages or advantageous developments of Invention result from the dependent claims or the Description.
  • Figure 1 shows a control loop for adjustment a work machine in a schematic representation, being a single-acting 4/4 proportional control valve used and developed according to the invention.
  • figure 2 is a control loop with a double acting control valve shown.
  • Figure 3 shows the control characteristic of the Control loop according to Figure 2 using a Pressure curve diagram.
  • FIG. 1 In Figure 1 with 10 is shown schematically electrohydraulic control circuit of a conventional Designated work machine 11.
  • the well-known Working machine 11 is shown symbolically and points as Lifting device 12 has an indicated lifting ring.
  • the Lifting device 12 is in a manner not shown in the Housing of the working machine 11 and mounted works with one adjustment device from two opposing piston / cylinder units 14.1 and 14.2 together.
  • the piston / cylinder units 14.1 and 14.2 differ in the size of their piston surfaces and are hydraulically loaded.
  • the work machine according to FIG. 1 is as a radial piston machine or as a vane machine drawn, but it is not on these types limited.
  • the invention is also based on Axial piston machines transferable.
  • the invention is also regardless of whether the work machines 11 as pumps or Motors are operated.
  • Main control variable of the control loop 10 shown 1 shows the instantaneous position of the lifting device 12, to detect one of the piston / cylinder units 14.1 / 2 is provided with a displacement sensor 16.
  • the position sensor 16 is a conventionally known component, the a dependent on the position of the lifting device 12 electrical signal 18 generated.
  • This signal 18 is one Amplifier 20 supplied, the signal 18 with a Compare setpoint 22. From the discrepancies between the The amplifier 20 forms the desired value 22 and the signal 18 electrical control signal 24 for a control valve 26.
  • Das Control valve 26 converts the control signal 24 into hydraulic signal for the lifting device 12 of the Working machine 11 um.
  • the control valve 26 is a state of the art Technology essentially known 4/4 proportional control valve, which in a solenoid 28 and a hydraulic part 30 coupled thereto is structured.
  • the housing of the magnetic part 28 is a proportional magnet 32 arranged, the an anchor 34 in a spatial direction applied.
  • the armature 34 actuates one in the housing of the Hydraulic part 30 movably guided valve slide 36.
  • Der Valve slide 36 controls by means of control edges, which are transverse its longitudinal axis are arranged, the pressure medium flow of or to hydraulic channels and hydraulic connections 38, which in the Housing of the hydraulic part 30 are formed. With the Hydraulic connections 38 are connected to the lines various consumers, including to the piston / cylinder units 14.1 / 2 of the adjustment device of the Guide machine 11.
  • Valve spool 36 or the armature 34 is carried out by a Hydraulic part 30 arranged control spring 40.
  • This control spring 40 is based on the side facing away from the anchor 34 Valve spool 36 on this valve spool 36 itself and on Because of a housing-side spring chamber 42.
  • the control valve 26 is located opposite the spring chamber 42 a pressure chamber 44. The two ends of the Valve slide 36 protrude with its end faces in the Spring chamber 42 or into the pressure chamber 44.
  • connection 38.1 forms the inlet P of the control valve 26.
  • the connection 35.2 acts as work port B and is with the Piston cylinder unit 14.1 connected during the connection 38.3 connected as a return T to a reservoir 50 is.
  • the working connection designated 38.4 is in Embodiment is not required and is outward, for example by a plug, not shown locked.
  • Longitudinal channels 46.1 and 2 are formed, which interact allow between the individual connections 38.1 to 4.
  • the known hydraulic part 30 of the control valve 26 modified so that the Longitudinal channel 46.1, which is normally a connection from the Spring chamber 42 to the opposite pressure chamber 44 manufactures, is sealed pressure-tight.
  • This can for example a plug, not shown be used.
  • the control valve 26 Additional channels 48.1 and 2 formed, the spring chamber 42nd or contact the pressure chamber 44 hydraulically.
  • the Spring chamber 42 is connected to the additional channel 48.2 Storage container 50 connected and is thereby aerated, while the pressure chamber 44 with the additional channel 48.1 a pressure medium channel 52 is connected.
  • Position transducer 54 To detect the current position of the armature 34 or the Valve spool 36 is a second on the magnetic part 28 Position transducer 54 attached. This displacement sensor 54 generates in a known manner, a position signal 56, which is also the Amplifier 20 supplied and evaluated by this.
  • the described electro-hydraulic control circuit 10 is completed by a connecting channel 58 which leads from the high pressure side of the working machine 11 to the second piston / cylinder unit 14.2.
  • a control circuit 10 allows the adjustment or control of a work machine 11 according to its operating conditions.
  • practical operation has shown that, in exceptional cases, malfunctions or errors can occur in the electrical part of the control circuit 10, which in extreme cases can lead to a maximum adjustment of the machine 11.
  • the work machine 11 can empty the connected hydraulic circuit and then destroy itself due to a lack of lubricant. Helping access in such a case is only possible by timely interruption of the power supply to the drive motor.
  • the control circuit 10 has a safety device 60 according to the invention, which can be integrated into the hydraulic part 30 of the control valve 26.
  • the safety device 60 is switched on electrically after detection of a fault and sets the working machine 11 into a hydraulically controlled, uncritical operating state.
  • the safety device 60 consists of a Pressure medium channel 52, which is the high pressure side of the Machine 11 in the event of a fault with the reservoir 50 connects.
  • a switching valve 62 is located in the pressure medium channel 52 arranged that a pressure medium flow through the Pressure medium channel 52 only releases in the event of a fault. in the trouble-free operation of the working machine 11 is this Pressure medium flow blocked. Switching the switching valve 62 is caused by an electrical interference signal emitted by the Amplifier 20, for example in the event of an implausibility between the signal 18 and the target value 22 is output. At the same time, the current flow to this interference signal Solenoid coil of the proportional magnet 32 of the control valve 26 interrupted.
  • a pressure divider 64 switched in the pressure medium channel 52 is in series with the switching valve 62 a pressure divider 64 switched.
  • This pressure divider 64 will formed by two throttle devices 66.1 and 2, the first throttle device 66.1 the switching valve 62 is connected upstream. That in the area between the two Throttle devices 66.1 and 2 prevailing pressure level tapped via the additional channel 48.1 and the pressure chamber 44 of the control valve 26 supplied.
  • Valve slide 36 with a hydraulic force in the direction its longitudinal axis is applied.
  • the hydraulic power counteracts the force of the control spring 40 and is in it Size of the pressurized face of the Valve spool 36 determines.
  • the pressure divider 64 the force acts on the valve slide 36 proportional to the system pressure of the working machine 11.
  • this force becomes the valve spool 36 of the control valve 26 pressed towards the control spring 40, causing its Control edges the pressure medium flow from port 38.1 to Change connection 38.2 of hydraulic part 30.
  • the piston / cylinder unit 14.1 increases the pressure level, which a further employment of the lifting device 12 of the Working machine 11 causes.
  • the control loop described is based on each other coordinated dimensioning of the face of the Valve slide 26, the control spring 40 and the Throttle device 66.1 / 2 designed such that the Machine 11 in the event of a fault in an operating state is adjusted by setting a pressure level on your High-pressure side regulates that between the two Throttle devices 66.1 / 2 of the pressure divider 64 prevailing Pressure level corresponds.
  • This will be advantageous Pressure level regulated in the range between 10 and 20 bar.
  • Control valve 26a For some applications it is necessary double acting, i.e. in opposite directions use acting control valves 26a. Such a thing Control valve 26a is shown in Figure 2.
  • the control valve 26a has a double stroke magnet in its magnetic part 28a 70 on by an electronic control unit 72 is controlled.
  • the double stroke magnet 70 works with one Anchor 34 together, the valve spool 36 in Hydraulic part 30 actuated.
  • This valve slide 36 instructs both ends on a control spring 40, each on Valve slide 36 itself and at the base of its spring chamber 42 supported.
  • the valve spool 36 are transverse to it Longitudinal axis extending control edges formed Hydraulic channels and hydraulic connections 38 control the Housing of the hydraulic part 30 are formed.
  • the Hydraulic part 30 of the exemplary embodiment has a total of four Hydraulic connections 38.1 to 4, the inlet 38.1, as Return 38.2 and as working connections 38.3 and 38.4 Act. With regard to the contacting of the connections 38.1 to 4, reference is made to FIG. 1 in order to avoid repetitions. Is also identical to the first embodiment, that the longitudinal channel 46 connecting the spring chambers 42 is closed pressure-tight, and that the spring chambers 42nd are contacted hydraulically via additional channels 48.1 / 2.
  • the Safety device 60a This safety device 60a consists of a pressure medium channel 52a, which on the High pressure side of the work machine 11 begins. The Pressure medium channel 52a is the fault-free operation Work machine 11 shut off by a switching valve 62.
  • the switching valve 62 becomes electrical switched and releases the pressure medium flow.
  • this Switching valve 62 branches the pressure medium channel 52a in two channel branches 74.1 / 2, which are parallel to each other Guide storage container 50.
  • both channel branches 74.1 / 2 is one pressure divider 64.1 / 2 each from two in a row switched throttle devices 66.1 / 2 arranged.
  • the Pressure level in the pressure dividers 74.1 / 2 is tapped and through the additional channels 48.1 / 2 the spring chambers 42 of the Control valve 26a supplied.
  • Throttle device 66.2 has a branch channel 76, which of a pressure relief valve 78 is switched.
  • This Pressure relief valve 78 has a return spring and is controlled by the pressure in the pressure divider 64.2.
  • a safety device 60a designed in this way generates a control characteristic as shown in FIG. 3 is shown.
  • Figure 3 the pressure 80.1 / 2 in the Pressure dividers 64.1 / 2 depending on the system pressure 82 of the Work machine 11 applied.
  • the diagram shows that with increasing system pressure 82 the pressure 80.2 of the pressure divider 64.2 initially rises faster than the pressure 80.1 of the Pressure distributor 64.1. Only after passing through the pressure relief valve 78 ( Figure 2) set Pressure threshold 84, the pressure 80.2 remains in the pressure divider 64.2 at a constant level, while the pressure 80.1 in Pressure divider 64.1 continues to rise unchanged and thus that Pressure divider level exceeds 64.2.
  • the working machine 11 means this control characteristic that the lifting device 12 by the control valve 26a as long is issued as long as the pressure 80.2 in the pressure divider 64.2 is greater than the pressure prevailing in the pressure divider 64.1. If the pressures in the pressure dividers 64 are the same, that remains Issue of lifting device 12 constant while at opposite pressure conditions is withdrawn.
  • the work machine 11 is characterized by this control characteristic In the event of a fault, hydraulically into an operating state adjusted and held in the machine provides a system pressure 82 which is in the range between the 2-bis 3 times the set pressure at the pressure relief valve 78 lies.
  • Deviate invention Of course, changes or additions to the Embodiment possible without the basic idea of Deviate invention.
  • Essential to the invention is that conventionally known electrohydraulic controls for Working machines 11 by relatively easy to manufacture Measures on control valve 26 with safety devices 60 can be equipped with a self-destruction and an unintentional employment on full delivery of the Prevent machine 11 in the event of a fault.
  • the Safety device 60 can be used without the construction volume enlarge into the hydraulic part 30 of the control valve 26 integrate.
  • the safety device 60 is off affordable and maintenance-free hydraulic components built up.

Description

Stand der TechnikState of the art

Die Erfindung geht von einer verstellbaren hydraulischen Arbeitsmaschine entsprechend der Gattung des Anspruchs 1 aus. Eine derartige Arbeitsmaschine in Form einer Radialkolbenpumpe ist beispielsweise aus der DE-A-3 140 397 oder DE 44 10 719.6 A1 bereits bekannt. Diese Radialkolbenpumpe ist mit einer Reihe von Sensoren ausgestattet, deren Signale in einem Steuergerät ausgewertet und zu einem Ansteuersignal für eine Verstelleinrichtung verarbeitet werden, die auf die Hubeinrichtung der Radialkolbenpumpe einwirkt. Ziel dieser Anordnung ist es, einen möglichst geräuscharmen Lauf der Radialkolbenpumpe zu erreichen. Kommt es dabei zu einem Fehlverhalten der Verstelleinrichtung, so kann die Radialkolbenpumpe auf maximale Fördermenge eingestellt werden. Im Extremfall, d.h. falls die Druckversorgung der Verstelleinrichtung nicht über den Pumpenauslaß sondern über eine externe Einrichtung erfolgt, kann dies zum Leersaugen des angeschlossenen hydraulischen Systems und danach durch Schmierstoffmangel zur Selbstzerstörung der Radialkolbenpumpe führen. The invention is based on an adjustable hydraulic Working machine according to the preamble of claim 1 out. Such a machine in the form of a Radial piston pump is for example from DE-A-3 140 397 or DE 44 10 719.6 A1 is already known. This radial piston pump is equipped with a number of sensors whose signals evaluated in a control unit and to a control signal be processed for an adjustment device that on the Radial piston pump lifting device acts. Aim this The arrangement is to run as quietly as possible To reach radial piston pump. If there is one Mishandling of the adjustment device, the Radial piston pump set to maximum flow become. In extreme cases, i.e. if the pressure supply of the Adjustment device not via the pump outlet but via If an external device is used, this can be done for vacuuming of the connected hydraulic system and then through Lack of lubricant to self-destruct the Guide the radial piston pump.

Vorteile der ErfindungAdvantages of the invention

Demgegenüber weist die erfindungsgemäße Arbeitsmaschine mit den kennzeichnenden Merkmalen des Anspruchs 1 den Vorteil einer zuschaltbaren hydraulischen Sicherheitseinrichtung auf, die die Arbeitsmaschine im Fehlerfall in Notlaufbetrieb umschaltet. In diesem Notlaufbetrieb wird die Arbeitsmaschine auf einen konstanten Betriebsdruck geregelt, bei dem die Selbstzerstörung der Arbeitsmaschine ausgeschlossen ist. Die Sicherheitseinrichtung läßt sich auf relativ einfache Weise in das Regelventil der Verstelleinrichtung integrieren und ist aus verhältnismäßig einfachen und damit preisgünstigen hydraulischen Bauteilen aufgebaut. Die erforderlichen Bauteile vergrößern das Bauvolumen des Regelventils allenfalls unwesentlich. Weitere Vorteile oder vorteilhafte Weiterbildungen der Erfindung ergeben sich aus den Unteransprüchen oder der Beschreibung.In contrast, the work machine according to the invention has the characterizing features of claim 1 the advantage a switchable hydraulic safety device on the machine in the event of a fault in emergency operation switches. In this emergency operation, the Machine regulated to a constant operating pressure, in which the self-destruction of the work machine is excluded. The safety device can be opened relatively simple way in the control valve Integrate adjustment device and is proportionate simple and therefore inexpensive hydraulic components built up. The required components enlarge it Construction volume of the control valve is at most insignificant. Further advantages or advantageous developments of Invention result from the dependent claims or the Description.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Figur 1 zeigt einen Regelkreis zur Verstellung einer Arbeitsmaschine in einer schematischen Darstellung, wobei ein einfach wirkendes 4/4-Proportionalregelventil eingesetzt und erfindungsgemäß weitergebildet ist. In Figur 2 ist ein Regelkreis mit einem doppeltwirkenden Regelventil dargestellt. Figur 3 zeigt die Regelcharakteristik des Regelkreises nach Figur 2 anhand eines Druckverlaufdiagramms. An embodiment of the invention is in the drawing shown and in the description below explained. Figure 1 shows a control loop for adjustment a work machine in a schematic representation, being a single-acting 4/4 proportional control valve used and developed according to the invention. In figure 2 is a control loop with a double acting control valve shown. Figure 3 shows the control characteristic of the Control loop according to Figure 2 using a Pressure curve diagram.

Beschreibung des AusführungsbeispielsDescription of the embodiment

In Figur 1 ist mit 10 der schematisch dargestellte elektrohydraulische Regelkreis einer konventionellen Arbeitsmaschine 11 bezeichnet. Die an sich bekannte Arbeitsmaschine 11 ist symbolisch dargestellt und weist als Hubeinrichtung 12 einen angedeuteten Hubring auf. Die Hubeinrichtung 12 ist auf nicht dargestellte Weise im Gehäuse der Arbeitsmaschine 11 verschiebbar gelagert und wirkt mit einer Verstelleinrichtung aus zwei gegeneinanderwirkenden Kolben-/Zylindereinheiten 14.1 und 14.2 zusammen. Die Kolben-/Zylindereinheiten 14.1 und 14.2 unterscheiden sich in der Größe ihrer Kolbenflächen und sind hydraulisch beaufschlagt. Die Arbeitsmaschine nach Figur 1 ist als Radialkolbenmaschine bzw. als Flügelzellenmaschine gezeichnet, sie ist allerdings nicht auf diese Bauarten eingeschränkt. Beispielsweise ist die Erfindung auch auf Axialkolbenmaschinen übertragbar. Ebenso ist die Erfindung unabhängig davon, ob die Arbeitsmaschinen 11 als Pumpen oder Motoren betrieben werden.In Figure 1 with 10 is shown schematically electrohydraulic control circuit of a conventional Designated work machine 11. The well-known Working machine 11 is shown symbolically and points as Lifting device 12 has an indicated lifting ring. The Lifting device 12 is in a manner not shown in the Housing of the working machine 11 and mounted works with one adjustment device from two opposing piston / cylinder units 14.1 and 14.2 together. The piston / cylinder units 14.1 and 14.2 differ in the size of their piston surfaces and are hydraulically loaded. The work machine according to FIG. 1 is as a radial piston machine or as a vane machine drawn, but it is not on these types limited. For example, the invention is also based on Axial piston machines transferable. The invention is also regardless of whether the work machines 11 as pumps or Motors are operated.

Hauptsteuergröße des dargestellten Regelkreises 10 nach Figur 1 bildet die Momentanposition der Hubeinrichtung 12, zu deren Erfassung eine der Kolben-/Zylindereinheiten 14.1/2 mit einem Wegaufnehmer 16 versehen ist. Beim Wegaufnehmer 16 handelt es sich um ein herkömmlich bekanntes Bauteil, das ein von der Position der Hubeinrichtung 12 abhängiges elektrisches Signal 18 erzeugt. Dieses Signal 18 wird einem Verstärker 20 zugeführt, der dieses Signal 18 mit einem Sollwert 22 vergleicht. Aus den Abweichungen zwischen dem Sollwert 22 und dem Signal 18 bildet der Verstärker 20 ein elektrisches Ansteuersignal 24 für ein Regelventil 26. Das Regelventil 26 wandelt das Ansteuersignal 24 in ein hydraulisches Signal für die Hubeinrichtung 12 der Arbeitsmaschine 11 um.Main control variable of the control loop 10 shown 1 shows the instantaneous position of the lifting device 12, to detect one of the piston / cylinder units 14.1 / 2 is provided with a displacement sensor 16. At the position sensor 16 is a conventionally known component, the a dependent on the position of the lifting device 12 electrical signal 18 generated. This signal 18 is one Amplifier 20 supplied, the signal 18 with a Compare setpoint 22. From the discrepancies between the The amplifier 20 forms the desired value 22 and the signal 18 electrical control signal 24 for a control valve 26. Das Control valve 26 converts the control signal 24 into hydraulic signal for the lifting device 12 of the Working machine 11 um.

Beim Regelventil 26 handelt es sich um ein aus dem Stand der Technik im wesentlichen bekanntes 4/4-Proportionalregelventil, das in ein Magnetteil 28 und ein damit gekoppeltes Hydraulikteil 30 gegliedert ist. Im Gehäuse des Magnetteils 28 ist ein Proportionalmagnet 32 angeordnet, der einen Anker 34 in eine Raumrichtung beaufschlagt. Der Anker 34 betätigt einen im Gehäuse des Hydraulikteils 30 beweglich geführten Ventilschieber 36. Der Ventilschieber 36 steuert mittels Steuerkanten, die quer zu seiner Längsachse angeordnet sind, den Druckmittelfluß von oder zu Hydraulikkanälen und Hydraulikanschlüssen 38, die im Gehäuse des Hydraulikteils 30 ausgebildet sind. Mit den Hydraulikanschlüssen 38 sind Leitungen verbunden, die zu verschiedenen Verbrauchern, u.a. zu den Kolben/Zylindereinheiten 14.1/2 der Verstelleinrichtung der Arbeitsmaschine 11 führen. Die Rückstellung des Ventilschiebers 36 bzw. des Ankers 34 erfolgt durch eine im Hydraulikteil 30 angeordnete Regelfeder 40. Diese Regelfeder 40 stützt sich auf der vom Anker 34 abgewandten Seite des Ventilschiebers 36 an diesem Ventilschieber 36 selbst und am Grund einer gehäuseseitigen Federkammer 42 ab. Gegenüberliegend zur Federkammer 42 weist das Regelventil 26 eine Druckkammer 44 auf. Die beiden Enden des Ventilschiebers 36 ragen mit ihren Stirnseiten in die Federkammer 42 bzw. in die Druckkammer 44 hinein.The control valve 26 is a state of the art Technology essentially known 4/4 proportional control valve, which in a solenoid 28 and a hydraulic part 30 coupled thereto is structured. in the The housing of the magnetic part 28 is a proportional magnet 32 arranged, the an anchor 34 in a spatial direction applied. The armature 34 actuates one in the housing of the Hydraulic part 30 movably guided valve slide 36. Der Valve slide 36 controls by means of control edges, which are transverse its longitudinal axis are arranged, the pressure medium flow of or to hydraulic channels and hydraulic connections 38, which in the Housing of the hydraulic part 30 are formed. With the Hydraulic connections 38 are connected to the lines various consumers, including to the piston / cylinder units 14.1 / 2 of the adjustment device of the Guide machine 11. The provision of the Valve spool 36 or the armature 34 is carried out by a Hydraulic part 30 arranged control spring 40. This control spring 40 is based on the side facing away from the anchor 34 Valve spool 36 on this valve spool 36 itself and on Because of a housing-side spring chamber 42. The control valve 26 is located opposite the spring chamber 42 a pressure chamber 44. The two ends of the Valve slide 36 protrude with its end faces in the Spring chamber 42 or into the pressure chamber 44.

Am Gehäuse des Hydraulikteils 30 sind vier hydraulische Anschlüsse 38.1 bis 4 ausgebildet, wobei der Anschluß 38.1 den Zulauf P des Regelventils 26 bildet. Der Anschluß 35.2 wirkt als Arbeitsanschluß B und ist mit der Kolbenzylindereinheit 14.1 verbunden, während der Anschluß 38.3 als Rücklauf T mit einem Vorratsbehälter 50 verbunden ist. Der mit A bezeichnete Arbeitsanschluß 38.4 wird im Ausführungsbeispiel nicht benötigt und ist nach außen, beispielsweise durch einen nicht dargestellten Stopfen verschlossen. Im Gehäuse des Hydraulikteils 30 sind zudem Längskanäle 46.1 und 2 ausgebildet, die eine Wechselwirkung zwischen den einzelnen Anschlüssen 38.1 bis 4 ermöglichen. Erfindungsgemäß ist das an sich bekannte Hydraulikteil 30 des Regelventils 26 dahingehend modifiziert, daß der Längskanal 46.1, der normalerweise eine Verbindung von der Federkammer 42 zur gegenüberliegenden Druckkammer 44 herstellt, druckdicht verschlossen ist. Hierzu kann beispielsweise ein nicht gezeichneter Verschlußstopfen eingesetzt werden. Desweiteren sind am Regelventil 26 Zusatzkanäle 48.1 und 2 ausgebildet, die die Federkammer 42 bzw. die Druckkammer 44 hydraulisch kontaktieren. Die Federkammer 42 ist über den Zusatzkanal 48.2 mit dem Vorratsbehälter 50 verbunden und wird dadurch belüftet, während die Druckkammer 44 über den Zusatzkanal 48.1 mit einem Druckmittelkanal 52 verbunden ist.There are four hydraulic ones on the housing of the hydraulic part 30 Connections 38.1 to 4 are formed, the connection 38.1 forms the inlet P of the control valve 26. The connection 35.2 acts as work port B and is with the Piston cylinder unit 14.1 connected during the connection 38.3 connected as a return T to a reservoir 50 is. The working connection designated 38.4 is in Embodiment is not required and is outward, for example by a plug, not shown locked. In the housing of the hydraulic part 30 are also Longitudinal channels 46.1 and 2 are formed, which interact allow between the individual connections 38.1 to 4. According to the invention, the known hydraulic part 30 of the control valve 26 modified so that the Longitudinal channel 46.1, which is normally a connection from the Spring chamber 42 to the opposite pressure chamber 44 manufactures, is sealed pressure-tight. This can for example a plug, not shown be used. Furthermore, the control valve 26 Additional channels 48.1 and 2 formed, the spring chamber 42nd or contact the pressure chamber 44 hydraulically. The Spring chamber 42 is connected to the additional channel 48.2 Storage container 50 connected and is thereby aerated, while the pressure chamber 44 with the additional channel 48.1 a pressure medium channel 52 is connected.

Zur Erfassung der Momentanposition des Ankers 34 bzw. des Ventilschiebers 36 ist am Magnetteil 28 ein zweiter Wegaufnehmer 54 angebracht. Dieser Wegaufnehmer 54 erzeugt in bekannter Weise ein Positionssignal 56, das ebenfalls dem Verstärker 20 zugeführt und von diesem ausgewertet wird.To detect the current position of the armature 34 or the Valve spool 36 is a second on the magnetic part 28 Position transducer 54 attached. This displacement sensor 54 generates in a known manner, a position signal 56, which is also the Amplifier 20 supplied and evaluated by this.

Der beschriebene elektrohydraulische Regelkreis 10 wird durch einen Verbindungskanal 58 vervollständigt, der von der Hochdruckseite der Arbeitsmaschine 11 zur zweiten Kolben/Zylindereinheit 14.2 führt.
Ein derartiger Regelkreis 10 erlaubt die Verstellung bzw. Regelung einer Arbeitsmaschine 11 entsprechend ihren Einsatzbedingungen. Der Praxisbetrieb hat allerdings gezeigt, daß es in Ausnahmefällen zu Störungen oder Fehlern im elektrischen Teil des Regelkreises 10 kommen kann, die im Extremfall zu einer Maximalverstellung der Arbeitsmaschine 11 führen können. Dabei kann die Arbeitsmaschine 11 den angeschlossenen Hydraulikkreis entleeren und sich danach aufgrund von Schmierstoffmangel selbst zerstören. Ein helfender Zugriff in einem solchen Fall ist lediglich durch eine rechtzeitige Unterbrechung der Stromversorgung des Antriebsmotors möglich. Um eine Selbstzerstörung der Arbeitsmaschine 11 im Störfall sicher ausschließen zu können, weist der Regelkreis 10 eine erfindungsgemäße Sicherheitseinrichtung 60 auf, die sich in das Hydraulikteil 30 des Regelventils 26 integrieren läßt. Die Sicherheitseinrichtung 60 wird nach Erkennung eines Fehlers elektrisch zugeschaltet und verstellt die Arbeitsmaschine 11 in einen hydraulisch geregelten unkritischen Betriebszustand.The described electro-hydraulic control circuit 10 is completed by a connecting channel 58 which leads from the high pressure side of the working machine 11 to the second piston / cylinder unit 14.2.
Such a control circuit 10 allows the adjustment or control of a work machine 11 according to its operating conditions. However, practical operation has shown that, in exceptional cases, malfunctions or errors can occur in the electrical part of the control circuit 10, which in extreme cases can lead to a maximum adjustment of the machine 11. The work machine 11 can empty the connected hydraulic circuit and then destroy itself due to a lack of lubricant. Helping access in such a case is only possible by timely interruption of the power supply to the drive motor. In order to be able to reliably rule out self-destruction of the working machine 11 in the event of a malfunction, the control circuit 10 has a safety device 60 according to the invention, which can be integrated into the hydraulic part 30 of the control valve 26. The safety device 60 is switched on electrically after detection of a fault and sets the working machine 11 into a hydraulically controlled, uncritical operating state.

Hierzu besteht die Sicherheitseinrichtung 60 aus einem Druckmittelkanal 52, der die Hochdruckseite der Arbeitsmaschine 11 im Störungsfall mit dem Vorratsbehälter 50 verbindet. Im Druckmittelkanal 52 ist ein Schaltventil 62 angeordnet, das einen Druckmittelfluß durch den Druckmittelkanal 52 erst im Störungsfall freigibt. Im störungsfreien Betrieb der Arbeitsmaschine 11 ist dieser Druckmittelfluß gespertt. Die Umschaltung des Schaltventils 62 erfolgt durch ein elektrisches Störsignal, das vom Verstärker 20 beispielsweise im Falle einer Unplausibilität zwischen dem Signal 18 und dem Sollwert 22 ausgegeben wird. Gleichzeitig wird durch dieses Störsignal der Stromfluß zur Magnetspule des Proportionalmagneten 32 des Regelventils 26 unterbrochen.For this purpose, the safety device 60 consists of a Pressure medium channel 52, which is the high pressure side of the Machine 11 in the event of a fault with the reservoir 50 connects. A switching valve 62 is located in the pressure medium channel 52 arranged that a pressure medium flow through the Pressure medium channel 52 only releases in the event of a fault. in the trouble-free operation of the working machine 11 is this Pressure medium flow blocked. Switching the switching valve 62 is caused by an electrical interference signal emitted by the Amplifier 20, for example in the event of an implausibility between the signal 18 and the target value 22 is output. At the same time, the current flow to this interference signal Solenoid coil of the proportional magnet 32 of the control valve 26 interrupted.

In den Druckmittelkanal 52 ist in Reihe mit dem Schaltventil 62 ein Druckteiler 64 geschaltet. Dieser Druckteiler 64 wird von zwei Drosseleinrichtungen 66.1 und 2 gebildet, wobei die erste Drosseleinrichtung 66.1 dem Schaltventil 62 vorgeschaltet ist. Das im Bereich zwischen den beiden Drosseleinrichtungen 66.1 und 2 herrschende Druckniveau wird über den Zusatzkanal 48.1 abgegriffen und der Druckkammer 44 des Regelventils 26 zugeführt.In the pressure medium channel 52 is in series with the switching valve 62 a pressure divider 64 switched. This pressure divider 64 will formed by two throttle devices 66.1 and 2, the first throttle device 66.1 the switching valve 62 is connected upstream. That in the area between the two Throttle devices 66.1 and 2 prevailing pressure level tapped via the additional channel 48.1 and the pressure chamber 44 of the control valve 26 supplied.

Dadurch wird es erreicht, daß im Fehlerfall der Ventilschieber 36 mit einer hydraulischen Kraft in Richtung seiner Längsachse beaufschlagt wird. Die hydraulische Kraft wirkt der Kraft der Regelfeder 40 entgegen und wird in ihrer Größe von der druckbeaufschlagten Stirnfläche des Ventilschiebers 36 bestimmt. Aufgrund des Druckteilers 64 verhält sich die Kraft auf den Ventilschieber 36 proportional zum Systemdruck der Arbeitsmaschine 11. Infolge dieser Kraft wird der Ventilschieber 36 des Regelventils 26 in Richtung der Regelfeder 40 gedrückt, wodurch seine Steuerkanten den Druckmittelfluß vom Anschluß 38.1 zum Anschluß 38.2 des Hydraulikteils 30 verändern. Damit wird in der Kolben-/Zylindereinheit 14.1 das Druckniveau erhöht, was eine weitere Anstellung der Hubeinrichtung 12 der Arbeitsmaschine 11 bewirkt.It is thereby achieved that the Valve slide 36 with a hydraulic force in the direction its longitudinal axis is applied. The hydraulic power counteracts the force of the control spring 40 and is in it Size of the pressurized face of the Valve spool 36 determines. Because of the pressure divider 64 the force acts on the valve slide 36 proportional to the system pressure of the working machine 11. As a result this force becomes the valve spool 36 of the control valve 26 pressed towards the control spring 40, causing its Control edges the pressure medium flow from port 38.1 to Change connection 38.2 of hydraulic part 30. With that, in the piston / cylinder unit 14.1 increases the pressure level, which a further employment of the lifting device 12 of the Working machine 11 causes.

Der beschriebene Regelkreis ist durch die aufeinander abgestimmte Dimensionierung der Stirnfläche des Ventilschiebers 26, der Regelfeder 40 und der Drosseleinrichtung 66.1/2 derart ausgelegt, daß die Arbeitsmaschine 11 im Fehlerfall in einen Betriebszustand verstellt wird, in dem sie ein Druckniveau auf ihrer Hochdruckseite einregelt, das dem zwischen den beiden Drosseleinrichtungen 66.1/2 des Druckteilers 64 herrschenden Druckniveau entspricht. Vorteilhafterweise wird dieses Druckniveau im Bereich zwischen 10 und 20 bar geregelt.The control loop described is based on each other coordinated dimensioning of the face of the Valve slide 26, the control spring 40 and the Throttle device 66.1 / 2 designed such that the Machine 11 in the event of a fault in an operating state is adjusted by setting a pressure level on your High-pressure side regulates that between the two Throttle devices 66.1 / 2 of the pressure divider 64 prevailing Pressure level corresponds. This will be advantageous Pressure level regulated in the range between 10 and 20 bar.

Für manche Anwendungsfälle ist es erforderlich, doppeltwirkende, d.h. in gegenüberliegende Richtungen wirkende Regelventile 26a einzusetzen. Ein derartiges Regelventil 26a ist in Figur 2 dargestellt. Das Regelventil 26a weist in seinem Magnetteil 28a einen Doppelhubmagneten 70 auf, der von einem elektronischen Steuergerät 72 angesteuert wird. Der Doppelhubmagnet 70 wirkt mit einem Anker 34 zusammen, der den Ventilschieber 36 im Hydraulikteil 30 betätigt. Dieser Ventilschieber 36 weist an beiden Enden eine Regelfeder 40 auf, die sich jeweils am Ventilschieber 36 selbst und am Grund ihrer Federkammer 42 abstützt. Am Ventilschieber 36 sind quer zu seiner Längsachse verlaufende Steuerkanten ausgebildet, die Hydraulikkanäle und Hydraulikanschlüsse 38 steuern, die im Gehäuse des Hydraulikteils 30 ausgebildet sind. Das Hydraulikteil 30 des Ausführungsbeispiels hat insgesamt vier Hydraulikanschlüsse 38.1 bis 4, die als Zulauf 38.1, als Rücklauf 38.2 und als Arbeitsanschlüsse 38.3 und 38.4 wirken. Bezüglich der Kontaktierung der Anschlüsse 38.1 bis 4 sei auf Figur 1 verwiesen, um Wiederholungen zu vermeiden. Ebenfalls identisch mit dem ersten Ausführungsbeispiel ist, daß der die Federkammern 42 verbindende Längskanal 46 druckdicht verschlossen ist, und daß die Federkammern 42 hydraulisch über Zusatzkanäle 48.1/2 kontaktiert sind. Aufwendiger ausgebildet ist demgegenüber die Sicherheitseinrichtung 60a. Diese Sicherheitseinrichtung 60a besteht aus einem Druckmittelkanal 52a, der auf der Hochdruckseite der Arbeitsmaschine 11 beginnt. Der Druckmittelkanal 52a ist bei störungsfreiem Betrieb der Arbeitsmaschine 11 durch ein Schaltventil 62 abgesperrt. Im Störungsfall wird das Schaltventil 62 elektrisch umgeschaltet und gibt den Druckmittelfluß frei. Nach dem Schaltventil 62 verzweigt sich der Druckmittelkanal 52a in zwei Kanalzweige 74.1/2, die parallel zueinander zum Vorratsbehälter 50 führen. In beiden Kanalzweigen 74.1/2 ist jeweils ein Druckteiler 64.1/2 aus zwei hintereinander geschalteten Drosseleinrichtungen 66.1/2 angeordnet. Das Druckniveau in den Druckteilern 74.1/2 wird abgegriffen und durch die Zusatzkanäle 48.1/2 den Federkammern 42 des Regelventils 26a zugeführt. Der Kanalzweig 74.2, dessen Druck im Druckteiler 64.2 der dem Anker 34 zugewandten Federkammer 42 zugeführt wird, weist im Bereich zwischen dem Druckabgriff und der dem Vorratsbehälter 50 zugewandten Drosseleinrichtung 66.2 einen Stichkanal 76 auf, der von einem Druckbegrenzungsventil 78 geschaltet wird. Dieses Druckbegrenzungsventil 78 weist eine Rückstellfeder auf und wird vom Druck im Druckteiler 64.2 angesteuert.For some applications it is necessary double acting, i.e. in opposite directions use acting control valves 26a. Such a thing Control valve 26a is shown in Figure 2. The control valve 26a has a double stroke magnet in its magnetic part 28a 70 on by an electronic control unit 72 is controlled. The double stroke magnet 70 works with one Anchor 34 together, the valve spool 36 in Hydraulic part 30 actuated. This valve slide 36 instructs both ends on a control spring 40, each on Valve slide 36 itself and at the base of its spring chamber 42 supported. The valve spool 36 are transverse to it Longitudinal axis extending control edges formed Hydraulic channels and hydraulic connections 38 control the Housing of the hydraulic part 30 are formed. The Hydraulic part 30 of the exemplary embodiment has a total of four Hydraulic connections 38.1 to 4, the inlet 38.1, as Return 38.2 and as working connections 38.3 and 38.4 Act. With regard to the contacting of the connections 38.1 to 4, reference is made to FIG. 1 in order to avoid repetitions. Is also identical to the first embodiment, that the longitudinal channel 46 connecting the spring chambers 42 is closed pressure-tight, and that the spring chambers 42nd are contacted hydraulically via additional channels 48.1 / 2. In contrast, the Safety device 60a. This safety device 60a consists of a pressure medium channel 52a, which on the High pressure side of the work machine 11 begins. The Pressure medium channel 52a is the fault-free operation Work machine 11 shut off by a switching valve 62. in the In the event of a fault, the switching valve 62 becomes electrical switched and releases the pressure medium flow. After this Switching valve 62 branches the pressure medium channel 52a in two channel branches 74.1 / 2, which are parallel to each other Guide storage container 50. In both channel branches 74.1 / 2 is one pressure divider 64.1 / 2 each from two in a row switched throttle devices 66.1 / 2 arranged. The Pressure level in the pressure dividers 74.1 / 2 is tapped and through the additional channels 48.1 / 2 the spring chambers 42 of the Control valve 26a supplied. The channel branch 74.2, the Pressure in the pressure divider 64.2 facing the armature 34 Spring chamber 42 is supplied points in the area between the Pressure tap and the one facing the reservoir 50 Throttle device 66.2 has a branch channel 76, which of a pressure relief valve 78 is switched. This Pressure relief valve 78 has a return spring and is controlled by the pressure in the pressure divider 64.2.

Eine derartig ausgebildete Sicherheitseinrichtung 60a erzeugt eine Regelcharakteristik, wie sie in Figur 3 dargestellt ist. In Figur 3 ist dazu der Druck 80.1/2 in den Druckteilern 64.1/2 in Abhängigkeit vom Systemdruck 82 der Arbeitsmaschine 11 aufgetragen. Das Diagramm zeigt, daß mit steigendem Systemdruck 82 der Druck 80.2 des Druckteilers 64.2 zunächst schneller steigt, als der Druck 80.1 des Druckverteilers 64.1. Erst nach Überschreiten einer durch das Druckbegrenzungsventil 78 (Figur 2) festgelegten Druckschwelle 84 verbleibt der Druck 80.2 im Druckteiler 64.2 auf einem konstanten Niveau, während der Druck 80.1 im Druckteiler 64.1 unverändert weiter ansteigt und damit das Niveau des Druckteilers 64.2 übersteigt. Für die Arbeitsmaschine 11 bedeutet diese Regelcharakteristik, daß deren Hubeinrichtung 12 durch das Regelventil 26a solange ausgestellt wird, solange der Druck 80.2 im Druckteiler 64.2 größer ist als der im Druckteiler 64.1 herrschende Druck. Bei Gleichheit der Drücke in den Druckteilern 64 bleibt die Ausstellung der Hubeinrichtung 12 konstant, während sie bei entgegengesetzten Druckverhältnissen zurückgenommen wird. Durch diese Regelcharakteristik wird die Arbeitsmaschine 11 im Störungsfall hydraulisch in einen Betriebszustand verstellt und darin gehalten, in dem die Arbeitsmaschine einen Systemdruck 82 liefert, der im Bereich zwischen dem 2-bis 3-fachen des Einstelldrucks am Druckbegrenzungsventil 78 liegt.A safety device 60a designed in this way generates a control characteristic as shown in FIG. 3 is shown. In Figure 3, the pressure 80.1 / 2 in the Pressure dividers 64.1 / 2 depending on the system pressure 82 of the Work machine 11 applied. The diagram shows that with increasing system pressure 82 the pressure 80.2 of the pressure divider 64.2 initially rises faster than the pressure 80.1 of the Pressure distributor 64.1. Only after passing through the pressure relief valve 78 (Figure 2) set Pressure threshold 84, the pressure 80.2 remains in the pressure divider 64.2 at a constant level, while the pressure 80.1 in Pressure divider 64.1 continues to rise unchanged and thus that Pressure divider level exceeds 64.2. For the Working machine 11 means this control characteristic that the lifting device 12 by the control valve 26a as long is issued as long as the pressure 80.2 in the pressure divider 64.2 is greater than the pressure prevailing in the pressure divider 64.1. If the pressures in the pressure dividers 64 are the same, that remains Issue of lifting device 12 constant while at opposite pressure conditions is withdrawn. The work machine 11 is characterized by this control characteristic In the event of a fault, hydraulically into an operating state adjusted and held in the machine provides a system pressure 82 which is in the range between the 2-bis 3 times the set pressure at the pressure relief valve 78 lies.

Selbstverständlich sind Änderungen oder Ergänzungen am Ausführungsbeispiel möglich ohne vom Grundgedanken der Erfindung abzuweichen. Erfindungswesentlich dabei ist, daß herkömmlich bekannte elektrohydraulische Regelungen für Arbeitsmaschinen 11 durch relativ einfach herzustellende Maßnahmen am Regelventil 26 mit Sicherheitseinrichtungen 60 ausgestattet werden können, die eine Selbstzerstörung und eine unbeabsichtigte Anstellung auf volle Fördermenge der Arbeitsmaschine 11 im Fehlerfall sicher verhindern. Die Sicherheitseinrichtung 60 läßt sich ohne das Bauvolumen zu vergrößern in das Hydraulikteil 30 des Regelventil 26 integrieren. Zudem ist die Sicherheitseinrichtung 60 aus preisgünstigen und wartungsfreien Hydraulikbauteilen aufgebaut.Of course, changes or additions to the Embodiment possible without the basic idea of Deviate invention. Essential to the invention is that conventionally known electrohydraulic controls for Working machines 11 by relatively easy to manufacture Measures on control valve 26 with safety devices 60 can be equipped with a self-destruction and an unintentional employment on full delivery of the Prevent machine 11 in the event of a fault. The Safety device 60 can be used without the construction volume enlarge into the hydraulic part 30 of the control valve 26 integrate. In addition, the safety device 60 is off affordable and maintenance-free hydraulic components built up.

Claims (7)

  1. Adjustable hydraulic working machine (11) with an adjusting device (14.1/2) which acts on a lifting device (12) and which is activated by an electrohydraulic regulating valve (26) having a valve slide (36), characterized in that the regulating valve (26) cooperates with a safety device (60) which, in the event of faults in the activation of the adjusting device (14.1/2), acts upon the valve slide (36) of the regulating valve (26) with a hydraulic force, in such a way that the regulating valve (26) brings the connected adjusting device (14.1/2) into a position, and regulates it in that position, in which the working machine (11) generates an at least approximately constant system pressure.
  2. Adjustable hydraulic working machine (11) according to Claim 1, characterized in that the safety device (60) has a switching valve (62) and at least one pressure divider (64) consisting of at least two throttle devices (66), and in that the switching valve (62) and the pressure divider (64) are connected in series in a pressure-medium duct (52) which connects the high-pressure side of the working machine (11) to the low-pressure side.
  3. Adjustable hydraulic working machine (11) according to one of Claims 1 or 2, characterized in that the safety device (60) is integrated into the housing of the regulating valve (26).
  4. Adjustable hydraulic working machine (11) according to one of Claims 1 to 3, characterized in that the regulating valve (26) has formed in it chambers (42, 44), into which the valve slide (36) projects with the end faces of its ends, in that these chambers (42, 44) are uncoupled hydraulically from one another, and in that, in the event of a fault, at least one of the chambers (42, 44) is filled with pressure medium.
  5. Adjustable hydraulic working machine (11) according to Claim 4, characterized in that the pressure medium filling the at least one chamber (42, 44) is under a pressure which corresponds to the pressure in the divider (64).
  6. Adjustable hydraulic working machine (11) according to one of Claims 1 to 5, characterized in that the working machine (11) is a piston machine, in particular a radial-piston or an axial-piston machine.
  7. Adjustable hydraulic working machine (11) according to one of Claims 1 to 5, characterized in that the working machine (11) is a vane-cell machine.
EP98105057A 1997-06-12 1998-03-20 Pressure limiting control circuit for the safe operation of a variable displacement radial or axial hydraulic piston pump or vane cell machine Expired - Lifetime EP0884476B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19724870 1997-06-12
DE19724870A DE19724870A1 (en) 1997-06-12 1997-06-12 Adjustable hydraulic work machine

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EP0884476A2 EP0884476A2 (en) 1998-12-16
EP0884476A3 EP0884476A3 (en) 1999-02-03
EP0884476B1 true EP0884476B1 (en) 2003-10-22

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EP (1) EP0884476B1 (en)
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Publication number Priority date Publication date Assignee Title
CN100485196C (en) * 2006-02-11 2009-05-06 中国矿业大学 Electrohydraulic unloading valve with both hydraulic control mode and electrohydraulic control mode
WO2013037582A1 (en) 2011-09-16 2013-03-21 Robert Bosch Gmbh Adjustment device for a hydrostatic machine and hydrostatic machine
FR2993940B1 (en) * 2012-07-24 2018-11-09 Poclain Hydraulics Industrie HYDRAULIC CONTROL CIRCUIT WITH SAFETY IN CASE OF COMMAND BREAK
DE102016014361A1 (en) 2016-12-02 2018-06-07 Alpha Fluid Hydrauliksysteme Müller GmbH Proportional valve in hydraulic systems
DE102017222355A1 (en) * 2017-12-11 2019-06-13 Robert Bosch Gmbh Control device with electro-proportional control behavior and double solenoid
DE102021118806B3 (en) 2021-07-21 2022-10-13 Pierburg Pump Technology Gmbh Method for controlling an electrically driven fluid pump for a vehicle and an electrically driven fluid pump for a vehicle

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Publication number Priority date Publication date Assignee Title
DE3140397C2 (en) * 1981-10-10 1993-10-21 Bosch Gmbh Robert Pilot-controlled device for load-independent regulation of a pressure medium flow proportional to an electrical input signal
US4801247A (en) * 1985-09-02 1989-01-31 Yuken Kogyo Kabushiki Kaisha Variable displacement piston pump
DE4115606A1 (en) * 1991-05-14 1992-11-19 Putzmeister Maschf OVERLOAD PROTECTION DEVICE FOR A DRIVE ENGINE DESIGNED AS AN INTERNAL COMBUSTION ENGINE OF A MAIN PUMP OF A HYDRAULIC PRESSURE SUPPLY UNIT
DE4327313C2 (en) * 1993-08-13 2001-07-05 Mannesmann Rexroth Ag Process for regulating the pressure of a hydrostatic machine with an adjustable delivery volume
DE4410719A1 (en) 1994-03-28 1995-10-05 Bosch Gmbh Robert Electrohydraulically adjustable pump

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EP0884476A2 (en) 1998-12-16
DE19724870A1 (en) 1998-12-17
EP0884476A3 (en) 1999-02-03
DE59809947D1 (en) 2003-11-27
JPH1150968A (en) 1999-02-23

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