EP1588057A1 - Hydraulic system for linear drives controlled by a displacer element - Google Patents

Hydraulic system for linear drives controlled by a displacer element

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Publication number
EP1588057A1
EP1588057A1 EP04701896A EP04701896A EP1588057A1 EP 1588057 A1 EP1588057 A1 EP 1588057A1 EP 04701896 A EP04701896 A EP 04701896A EP 04701896 A EP04701896 A EP 04701896A EP 1588057 A1 EP1588057 A1 EP 1588057A1
Authority
EP
European Patent Office
Prior art keywords
hydraulic system
valve
hydraulic
pressure
pump
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP04701896A
Other languages
German (de)
French (fr)
Other versions
EP1588057B1 (en
Inventor
Monika Ivantysynova
Robert Rahmfeld
Erik Lautner
Jürgen Weber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CNH Industrial Baumaschinen GmbH
Original Assignee
CNH Baumaschinen GmbH
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Filing date
Publication date
Application filed by CNH Baumaschinen GmbH filed Critical CNH Baumaschinen GmbH
Publication of EP1588057A1 publication Critical patent/EP1588057A1/en
Application granted granted Critical
Publication of EP1588057B1 publication Critical patent/EP1588057B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/08—Servomotor systems incorporating electrically operated control means
    • F15B21/082—Servomotor systems incorporating electrically operated control means with different modes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B7/00—Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors
    • F15B7/005—With rotary or crank input
    • F15B7/006—Rotary pump input

Definitions

  • the invention relates to a hydraulic system for displacement-controlled linear drives, in particular for mobile machines with at least one differential cylinder, at least one high-pressure circuit, which contains at least one pump with an adjustable delivery rate and is connected to a low-pressure system by at least two non-return valves which can be unlocked.
  • Hydraulic systems for mobile work machines are based today mainly on valve-controlled principles.
  • the various hydraulic consumers such as drives for the working hydraulics, steering, brakes, etc., are controlled by means of hydraulically or electrohydraulically controlled valve arrangements. controlled.
  • one or more central pressure supplies often in the form of load-sensing pumps, are used that provide pressure medium flows, which are influenced by single or multi-stage valve arrangements in accordance with the desired behavior of the hydraulic consumers.
  • a disadvantage of these valve-controlled hydraulic systems is, in particular, the poor energy efficiency.
  • pressure differences are required at the throttle edges of the valves, which in principle leads to high energy losses in hydraulic valve controls. It is not possible to use excess energy at one consumer of the system in the form of potential energy or braking energy for other consumers in the system and thereby to improve the system efficiency, which further worsens the heat development in the system.
  • a central pressure medium supply also has the disadvantage that in the event that several consumers have to be operated simultaneously, the volume flows are divided, which complicates the precise regulation and operation of the individual components.
  • Safety-relevant circuits in which it must be ensured that individual consumers, such as the steering or brakes, always have sufficient pressure medium available, must always be implemented, for example, using complicated priority valve arrangements.
  • a simultaneous movement of several consumers in the system leads to a different system behavior compared to individual movements. All of this leads to very complex and therefore costly and maintenance-intensive valve arrangements, the possibilities of which are also limited with regard to controllability and energy utilization.
  • displacement-controlled systems for rotary drives are used, in which a pump with adjustable displacement is used to control or regulate the movement of the hydraulic motor (s). The consumer is thus controlled solely by the volume flow made available by the pump, without a control valve or the like being used in the main circuit.
  • the object of the invention is therefore to provide a hydraulic system for linear drives with differential cylinders, in particular for mobile machines, which avoids the various disadvantages of the prior art by using a displacement control of the drives and enables precise, energy-efficient control of linear drives with differential cylinders, inexpensively and is easy to maintain and can be easily integrated into the overall hydraulic system of such machines.
  • the invention achieves this in that the check valves are connected to an electronic control device in such a way that switching-free switching is possible between the retraction or extension of the differential cylinder and a floating position function.
  • the check valves are located between the two high-pressure lines, which run from the adjustable pump to the differential cylinder, and the common low-pressure system.
  • the positive or negative differential volume flow occurring depending on the direction of movement of the piston can flow into the low-pressure system or be sucked out of it. If the volume flow is sucked in from the low pressure system, the corresponding check valve opens automatically. In the event of a flow of volume flow to the low pressure system, the corresponding check valve is unlocked by the system high pressure. To achieve a floating position, the two sides of the Differential cylinders are hydraulically connected to each other, which enables free movement of the piston. For this purpose, the check valves are unlocked so that pressure medium can flow through them in both directions, regardless of the pump volume flow. In this case, the differential volume flow is also compensated for by the low pressure system.
  • the control device for regulating the pump delivery rate is designed electronically.
  • the delivery rate of adjustable pumps is usually controlled electro-hydraulically. It is therefore particularly advantageous if this control is applied in an integrated manner together with the control device of the check valves, so that safe and precise regulation of the complete circuit behavior is possible. This can prevent, for example, that the pump requests a volume flow when the check valves are unlocked, which would then be briefly closed by the unlocked check valves.
  • a further embodiment of the hydraulic system provides that the electronic African control device for controlling the check valves has an electro-hydraulic 4/2-way valve.
  • the unblocking connection of the check valves can be alternately connected to one or the other side of the high-pressure circuit, which corresponds to a switchover between the normal differential volume compensation and the floating position of the differential cylinder.
  • two electro-hydraulic 3/2-way valves can be used.
  • a special embodiment of the hydraulic system provides that a controllable shut-off valve is provided on at least one connection of the differential cylinder.
  • a controllable shut-off valve is provided on at least one connection of the differential cylinder.
  • Such a shut-off valve allows a connection of the cylinder to be shut off without leakage, which is particularly useful for realizing a holding function.
  • the volume flow of the pump brings the cylinder into a certain position and then the high-pressure connection of the differential cylinder is shut off, so that it remains in its position without the pump maintaining the pressure.
  • a shut-off valve is also provided on the second connection of the differential cylinder, the cylinder can be completely separated from the hydraulic circuit, while remaining in its position. In this state, the pump and the connected hydraulic circuit can be used to operate a further differential cylinder, which can then also be separated from the circuit via shut-off valves. This allows a further function in the Realize work machine that can alternatively be operated by the other existing cylinders.
  • the low-pressure system is designed as an accumulator charging circuit with an accumulator charging valve, a pump with hydraulic accumulator and a pressure limiting valve.
  • a design of the low pressure side is characterized by a particularly high energy efficiency.
  • the pump only pushes into the low-pressure system when the pressure drops below a set minimum.
  • the accumulator charging circuit ensures compliance with a low pressure level between adjustable limit values.
  • Such a low-pressure system can be designed centrally for the entire hydraulic system and can supply all displacement-controlled hydraulic circuits according to the invention.
  • a further embodiment of the hydraulic system according to the invention is characterized in that the controllable shut-off valve is designed as a seat valve with 3/2-way pilot control. It can also make sense for the controllable shut-off valve to be designed as a continuous valve. With such a valve, the corresponding blocking function of the connection can be easily implemented without the valve opening or closing too suddenly. This prevents unwanted pressure peaks in the system.
  • shut-off valves which may be continuously controllable, are provided for alternative and / or simultaneous actuation of further differential cylinders.
  • further functions can be implemented on the same high-pressure circuit by means of such valves, whereby these are always operated alternatively to one another.
  • the shut-off valves are switched so that the pump with the associated protection and compensation valves is each connected to a differential cylinder or a plurality of the same function connected in parallel and supplies them with pressure medium.
  • connections for a passive vibration damping system are provided on the high-pressure circuit.
  • damping systems consist of a hydraulic circuit with an accumulator, which reduces the vibrations of the implement, for example when driving with a raised load.
  • the vibration damping system is connected directly to at least one connection on one side of the high-pressure circuit and can be switched on and off in order to suppress the undesired vibration states in desired operating situations.
  • the electronic control device, the controllable valves and, if appropriate, other hydraulic system components present are designed with the adjustable pump as an integrated component.
  • Such an integration of the pump with a number of the valves and the control offers the advantage of an extremely compact design, which can be useful since these components are necessary for every hydraulic function driven by differential cylinder systems.
  • the integration reduces the number of individual components, the complexity of the overall system is reduced, the installation effort is reduced and the costs of such a system are reduced in comparison to conventional systems.
  • sensors are provided for detecting the system states, in particular the differential cylinder position and the hydraulic pressures. It may also make sense for an electronic control device device for controlling the controllable system components depending on the measured system state and user specifications.
  • the drive system according to the invention can also be controlled, i.e. operate in an open chain of effects.
  • the invention is also directed to a mobile work machine with at least one hydraulic system, as described in the preceding.
  • a plurality of high-pressure circuits with a common low-pressure circuit are provided.
  • this has the advantage of additional cost savings, since a single low-pressure circuit with a pump and the further components is sufficient to supply all the hydraulic systems according to the invention.
  • FIG. 1 a schematic basic circuit of a hydraulic system according to the invention
  • FIG. 2 a circuit of a hydraulic system according to the invention in an expanded version
  • FIG. 3 shows a further embodiment
  • FIG. 4 shows yet another embodiment
  • FIG. 5 shows an overall system for a mobile working machine
  • FIG. 6 shows another overall system for a mobile working machine machine.
  • a hydraulic system is used to control a hydraulic differential cylinder 2.
  • a pump 3 with an adjustable delivery volume and reversal of the delivery direction is connected to the two connections of the differential cylinder 2 via two lines 4 and 5.
  • the electronically controllable 4/2-way valve 10 also serves to implement a floating position function. If the valve 10 is switched over (floating position function), the unblocking connections of the check valves 7 and 8 are no longer connected to the opposite side, but to the side lying in their passage direction. As a result, the check valves 7 and 8 open as soon as a pressure is present in one of the two lines 4 or 5 which is slightly higher than the low pressure in the low-pressure system 9. The piston 6 can thus move freely in the differential cylinder 2.
  • the pump 3 is expediently set such that it does not require a volume flow, since this would also be compensated for by the quasi-short circuit through the check valves 7 and 8.
  • a controllable shut-off valve 11 is provided on a connection of the differential cylinder 2.
  • This side of the differential cylinder 2 can thus be shut off without leakage, as a result of which the piston 6 is fixed in this position and a load located thereon is held. As a rule, this is the more heavily loaded piston side of the differential cylinder 2.
  • There are pressure sensors 12 in the system which are used to detect the states in serve the high pressure lines.
  • a displacement sensor 13 or an angle sensor in the kinematics of the work equipment, which detects the piston position, is located on the hydraulic differential cylinder 2.
  • the signals from the sensors 12 and 13 are processed by an electronic control device 14 together with user requests specified by corresponding control elements 15, and the corresponding manipulated variable is determined therefrom, which is transmitted to the electronic control device 16. This then controls the adjustable pump 3 in its displacement volume and thus the volume flow conveyed as well as, if applicable, the switching states of the electronic valves 10 and 11.
  • FIG. 2 An extension of this basic principle is shown in more detail in FIG. 2.
  • a hydraulic differential cylinder 2 is essentially connected directly to an adjustable pump 3.
  • the differential volume flow is compensated for during delivery by the two unblockable check valves 7 and 8, the unblocking connections of which are alternately connected to the opposite or adjacent sides of the high pressure circuit by an electrohydraulic 4/2-way valve 10.
  • an electrohydraulic 4/2-way valve 10 To protect the system from overpressures, two high-pressure safeguards 27 are provided.
  • the integrated electronic control device 14 controls the control of the individual components, such as the adjustable pump 3, taking into account the measured system states and the user specifications 15.
  • the second side of the differential cylinder 2 can also be shut off by an electronically controllable shut-off valve 17.
  • an additional differential cylinder 19 is located on two further electronically controllable shut-off valves 18 High pressure circuit connected.
  • the first differential cylinder 2 is separated from the hydraulic circuit by the two shut-off valves 11 and 17 and is thereby held in its position. Then the two shut-off valves 18 are opened so that a volume flow required by the pump 3 moves the second differential cylinder 19.
  • the differential volumes that occur are compensated again via the two unlockable check valves 7 and 8 in the low-pressure circuit 9.
  • the controllable shut-off valves 11, 17 and 18 can, in some applications, also be designed as continuous valves, so that they can be controlled continuously in special situations during operation and thus simultaneous operation of the two differential cylinders 2 and 19 is possible.
  • the low pressure in the low pressure system 9 is realized with an accumulator charging circuit.
  • a constant pump 20 with an accumulator charging valve 21 and a hydropneumatic accumulator 22 is used.
  • a pressure relief valve 23 protects the system against overload.
  • the accumulator loading valve 21 ensures that the constant pump 20 only delivers into the low-pressure system 9 when the pressure falls below a set minimum value. Since the accumulator charging valve 21 ensures pure pressure maintenance, the system can be implemented in an energy-efficient manner.
  • other combinations for realizing the low pressure system 9 are also possible, for example via a simple combination of a constant pump, accumulator and pressure relief valve or by means of a variable displacement pump.
  • This low pressure is also used behind the connection 24 of the adjustable pump 3 to operate the electro-hydraulic adjustment system of this pump.
  • the connections 25 and 26 are used to connect a passive vibration damper system. stems on the differential cylinder 2.
  • FIG. 3 shows a first modification of the basic principle, in which two 3/2-way valves 28, 29 are used instead of the electrohydraulic 4/2-way valve in order to realize the floating position by switching over the unlocking connections of the unlockable check valves 7, 8 , Furthermore, the low pressure is now applied via a constant pump 20 with a hydropneumatic accumulator 22 and a pressure relief valve 23.
  • 4 shows a further modification of the basic principle.
  • the floating position is achieved via a bypass by two valves 30, 31, i.e. when the valves are energized, the two cylinder chambers are connected to the low pressure and the differential cylinder 2 can move freely.
  • the low pressure is impressed here via a variable displacement pump 20 'with a hydropneumatic accumulator 22 and secured by a pressure relief valve 23.
  • this diagram also shows another possibility of supplying the third function with the pump 3.
  • Two 3/2-way valves 32, 33 at connections 34, 35 can simply switch the pump 3 to the third function when activated.
  • FIG. 5 shows an overall system for a mobile working machine (here wheel loader) with displacement-controlled working hydraulics according to the previously described displacement-controlled linear drive principle (valveless principle) and hydrostatic travel drive.
  • the simple coupling of several actuators via the low pressure and with the hydrostatic travel drive further reduces the system effort.
  • FIG. 6 shows a further overall system (here wheel loader), a hydrostatic travel drive in the 2-motor concept with a detachable adjustment motor being present and the low pressure for all displacement-controlled ones Main functions are impressed by the return of the hydrostatic fan and a memory.
  • An accumulator charging valve connects the return of the fan to the low pressure only when low pressure volume flow is required.
  • the electro-hydraulic control of the adjustable pump 3 can be used to implement all other functionalities that are stored in the software, such as fork parallel guidance, automatic feedback control, end of stroke shutdown, variable blade stop, variable cylinder damping (soft dust), shaking or distribution functions on the blade for agricultural engineering Inserts etc.
  • the respective variable pump is addressed directly via the control of the device.
  • the displacement-controlled actuator can be operated both in position and speed control (example: parallel tool guidance) or in a controlled manner in an open control loop.
  • the control processes the operator's request as an input signal (for example via a joystick).

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Servomotors (AREA)
  • Valve Device For Special Equipments (AREA)

Abstract

The invention concerns a hydraulic system for linear drives with a differential cylinder, in particular for mobile machines which through the use of displacement-control of the drives avoids the many and diverse disadvantages of the state of the art and renders possible a precise and energy-efficient control of linear drives with differential cylinders, and which is economical and simple to maintain and which can be well integrated into the total hydraulic system of such machines.

Description

Hydrauliksystem für verdrängergesteuerte LinearantriebeHydraulic system for displacement controlled linear drives
Die Erfindung betrifft ein Hydrauliksystem für verdrängergesteuerte Linearantriebe, insbesondere für mobile Arbeitsmaschinen mit wenigstens einem Diffe- rentialzylinder, wenigstens einem Hochdruckkreis, der wenigstens eine Pumpe mit verstellbarer Fördermenge beinhaltet und durch wenigstens zwei entsperr- bare Rückschlagventile mit einem Niederdrucksystem verbunden ist.The invention relates to a hydraulic system for displacement-controlled linear drives, in particular for mobile machines with at least one differential cylinder, at least one high-pressure circuit, which contains at least one pump with an adjustable delivery rate and is connected to a low-pressure system by at least two non-return valves which can be unlocked.
Hydrauliksysteme für mobile Arbeitsmaschinen beruhen heutzutage überwiegend auf ventilgesteuerten Prinzipien. Dabei werden mittels hydraulisch oder elektrohydraulisch angesteuerter Ventilanordnungen die verschiedenen hydraulischen Verbraucher, wie Antriebe der Arbeitshydraulik, Lenkung, Bremsen u.a. gesteuert. Üblicherweise finden dazu eine oder mehrere zentrale Druckversorgungen, häufig in Form von Load- sensing- Pumpen, Verwendung, die Druckmittelflüsse zur Verfügung stellen, welche über ein- oder mehrstufige Ventil-anordnungen entsprechend dem gewünschten Verhalten der hydraulischen Ver-braucher beeinflusst werden.Hydraulic systems for mobile work machines are based today mainly on valve-controlled principles. The various hydraulic consumers, such as drives for the working hydraulics, steering, brakes, etc., are controlled by means of hydraulically or electrohydraulically controlled valve arrangements. controlled. Usually, one or more central pressure supplies, often in the form of load-sensing pumps, are used that provide pressure medium flows, which are influenced by single or multi-stage valve arrangements in accordance with the desired behavior of the hydraulic consumers.
Nachteilig an diesen ventilgesteuerten Hydrauliksystemen ist insbesondere der schlechte Energienutzungsgrad. Um die benötigten Druckmittelflüsse zu erreichen, sind an den Drosselkanten der Ventile Druckdifferenzen erforderlich, was prinzipiell in hydraulischen Ventilsteuerungen zu hohen Energieverlusten führt. Es ist nicht möglich, Energieüberschüsse an einem Verbraucher des Systems in Form von potentieller Energie oder Bremsenergie für andere Verbraucher im System zu nutzen und dadurch den Systemwirkungsgrad zu verbessern, was die Wärmeentwicklung im System nochmals verschlechtert. Eine zentrale Druckmittelversorgung besitzt außerdem den Nachteil, dass im Falle, dass mehrere Verbraucher gleichzeitig betrieben werden müssen, die Volumenströme aufgeteilt werden, was die genaue Regelung und Bedienung der einzelnen Komponenten erschwert. Sicherheitsrelevante Schaltungen, bei denen dafür gesorgt werden muss, dass einzelne Verbraucher, wie z.B. die Lenkung oder Bremse, immer genügend Druckmittel zur Verfügung haben, müssen beispielsweise immer über komplizierte Prioritätsventilanordnungen realisiert werden. Eine simultane Bewegung mehrerer Verbraucher im System führt zu einem unterschiedlichen Systemverhalten im Vergleich zu Einzelbewegungen. All dies führt zu sehr komplexen und damit kosten- und wartungsintensiven Ventilanordnungen, deren Möglichkeiten auch im Hinblick auf Regelbarkeit und Energieausnutzung beschränkt sind. Vereinzelt kommen auch verdrängergesteuerte Systeme für Rotationsantriebe zum Einsatz, bei denen eine im Verdrängungsvolumen verstellbare Pumpe zur Steuerung oder Regelung der Bewegung des Hydromotors/en genutzt wird. Der Verbraucher wird damit alleine über den durch die Pumpe zur Verfügung gestellten Volumenstrom gesteuert, ohne dass ein Regelventil oder ähnliches im Hauptkreis Verwendung findet. Bei der Übertragung dieses Steuerprinzips auf Linearantriebe mit Differentialzylinder tritt das Problem auf, dass das Zylindervolumen auf beiden Seiten des Zylinderkolbens unterschiedlich ist und dadurch bei der Bewegung Differenzvolumenströme auftreten, die durch unterschiedliche bekannte Lösungen ausgeglichen werden müssen. Die bisher bekannten derartigen verdrängergesteuerten Systeme sind allerdings äußerst unflexibel, verfügen über eine hohe Anzahl an Zusatzkomponenten bzw. Verdrängereinheiten und bieten nicht den Funktionsumfang und die Systemeinfachheit, die für den Einsatz in mobilen Arbeitsmaschinen nötig ist (z.B. DE 40 08 792 AI, DE 27 06 091 AI, CA 605 046, DT 23 49 351 so- wie Rahmfeld und Ivantysynova 2000, Energiesparender geregelter Linearantrieb mit Differentialzylinder, 2. IFK, S. 191-205, Dresden).A disadvantage of these valve-controlled hydraulic systems is, in particular, the poor energy efficiency. In order to achieve the required pressure medium flows, pressure differences are required at the throttle edges of the valves, which in principle leads to high energy losses in hydraulic valve controls. It is not possible to use excess energy at one consumer of the system in the form of potential energy or braking energy for other consumers in the system and thereby to improve the system efficiency, which further worsens the heat development in the system. A central pressure medium supply also has the disadvantage that in the event that several consumers have to be operated simultaneously, the volume flows are divided, which complicates the precise regulation and operation of the individual components. Safety-relevant circuits, in which it must be ensured that individual consumers, such as the steering or brakes, always have sufficient pressure medium available, must always be implemented, for example, using complicated priority valve arrangements. A simultaneous movement of several consumers in the system leads to a different system behavior compared to individual movements. All of this leads to very complex and therefore costly and maintenance-intensive valve arrangements, the possibilities of which are also limited with regard to controllability and energy utilization. In some cases, displacement-controlled systems for rotary drives are used, in which a pump with adjustable displacement is used to control or regulate the movement of the hydraulic motor (s). The consumer is thus controlled solely by the volume flow made available by the pump, without a control valve or the like being used in the main circuit. When this control principle is transferred to linear drives with a differential cylinder, the problem arises that the cylinder volume is different on both sides of the cylinder piston and, as a result, differential volume flows occur during the movement, which have to be compensated for by different known solutions. However, the previously known displacement-controlled systems of this type are extremely inflexible, have a large number of additional components or displacement units and do not offer the functional scope and the system simplicity that are necessary for use in mobile work machines (for example DE 40 08 792 AI, DE 27 06 091 AI, CA 605 046, DT 23 49 351 so- like Rahmfeld and Ivantysynova 2000, energy-saving regulated linear drive with differential cylinder, 2nd IFK, p. 191-205, Dresden).
Aufgabe der Erfindung ist es daher, ein Hydrauliksystem für Linearantriebe mit Differentialzylinder, insbesondere für mobile Arbeitsmaschinen zu schaffen, das durch die Verwendung einer Verdrängersteuerung der Antriebe die vielfältigen Nachteile des Standes der Technik vermeidet und eine präzise energieeffiziente Steuerung von Linearantrieben mit Differentialzylindern ermöglicht, kostengünstig und einfach zu warten ist und sich gut in das Gesamthydrauliksystem von derartigen Maschinen integrieren läßt. Die Erfindung erreicht dies dadurch, dass die Rückschlagventile mit einer elektronischen Steuerungsvorrichtung derart verbunden sind, dass ein schaltstoßfreies Umschalten zwischen einem Ein- bzw. Ausfahren des Differeπti- alzylinders und einer Schwimmstellungsfunktion möglich ist. Die Rückschlagventile befinden sich zwischen den beiden Hochdruckleitungen, die von der in ihrer Fördermenge verstellbaren Pumpe zum Differentialzylinder fuhren, und dem gemeinsamen Niederdracksystem. Wenn ein Volumenstrom durch die verstellbare Pumpe erzeugt und dadurch der Differentialzylinder bewegt wird, kann der je nach Bewegungsrichtung des Kolbens auftretende, positive oder negative Differenzvolumenstrom in das Niederdrucksystem abfließen bzw. aus diesem angesaugt werden. Im Fall des An- saugens von Volumenstrom aus dem Niederdrucksystem öffnet das entsprechende Rückschlagventil selbsttätig. Im Fall des Abfließens von Volumenstrom zum Niederdrucksystem wird das entsprechende Rückschlagventil vom Systemhochdruck entsperrt. Für die Realisierung einer Schwimmstellung müssen die beiden Seiten des Differentialzylinders hydraulisch miteinander verbunden werden, wodurch eine freie Bewegung des Kolbens ermöglicht wird. Dazu werden die Rückschlagventile entsperrt, so dass Druckmittel unabhängig vom Pumpenvolu- menstrom in beide Richtungen durch sie fließen kann. Der Differenzvolumenstrom wird in diesem Fall ebenfalls durch das Niederdrucksystem ausgeglichen.The object of the invention is therefore to provide a hydraulic system for linear drives with differential cylinders, in particular for mobile machines, which avoids the various disadvantages of the prior art by using a displacement control of the drives and enables precise, energy-efficient control of linear drives with differential cylinders, inexpensively and is easy to maintain and can be easily integrated into the overall hydraulic system of such machines. The invention achieves this in that the check valves are connected to an electronic control device in such a way that switching-free switching is possible between the retraction or extension of the differential cylinder and a floating position function. The check valves are located between the two high-pressure lines, which run from the adjustable pump to the differential cylinder, and the common low-pressure system. If a volume flow is generated by the adjustable pump and the differential cylinder is thereby moved, the positive or negative differential volume flow occurring depending on the direction of movement of the piston can flow into the low-pressure system or be sucked out of it. If the volume flow is sucked in from the low pressure system, the corresponding check valve opens automatically. In the event of a flow of volume flow to the low pressure system, the corresponding check valve is unlocked by the system high pressure. To achieve a floating position, the two sides of the Differential cylinders are hydraulically connected to each other, which enables free movement of the piston. For this purpose, the check valves are unlocked so that pressure medium can flow through them in both directions, regardless of the pump volume flow. In this case, the differential volume flow is also compensated for by the low pressure system.
Die Verwendung einer elektronischen Steuerung zum Schalten der Rückschlagventile ermöglicht, dass die Ventile beispielsweise auf Wunsch des Bedieners entsperren und damit die Schwimmstellung realisiert wird. Zusätzlich bietet sie aber den Vorteil, dass eine solche Umschaltung nur dann erfolgt, wenn bestimmte Druckverhältnisse im Hochdruckkreis herrschen, so dass Schaltstöße oder sonstige unerwünschte Zustände verhindert werden und ein Abstützen der am Differentialzylinder vorhandenen Last immer sicher vermieden wird. Eine solche Steuerungsvorrichtung ermöglicht außerdem weitere "Funktionen eines solchen verdrängergesteuerten Kreises, die in den folgenden Unteransprüchen näher beschrieben werden.The use of an electronic control for switching the check valves enables the valves to be unlocked, for example at the request of the operator, and thus the floating position is realized. In addition, however, it offers the advantage that such a switchover only takes place when certain pressure conditions prevail in the high-pressure circuit, so that switching surges or other undesirable conditions are prevented and support for the load on the differential cylinder is always reliably avoided. Such a control device also enables further "functions of such a displacement-controlled circuit, which are described in more detail in the following subclaims.
So kann vorgesehen sein, dass die Steuerungsvorrichtung zur Regelung der Pumpen- Fördermenge elektronisch ausgebildet ist. Die Fördermenge von verstellbaren Pumpen wird üblicherweise elektrohydraulisch gesteuert. Daher ist es besonders vorteilhaft, wenn diese Steuerung gemeinsam mit der Steuerungsvorrichtung der Rückschlagventile integriert angelegt wird, so dass eine sichere und genaue Regelung des kompletten Kreisverhaltens möglich wird. So läßt sich beispielsweise verhindern, dass die Pumpe beim Entsperren der Rückschlagventile einen Volumenstrom fordert, der dann durch die entsperrten Rückschlagventile kurz geschlossen wäre. Eine weitere Ausgestaltung des Hydrauliksystems sieht vor, dass die elektro- nische Steuerungsvorrichtung zur Ansteuerung der Rückschlagventile ein elektrohydraulisches 4/2- Wegeventil aufweist. Durch ein solches Ventil kann der Entsperr- Anschluss der Rückschlagventile wechselweise mit der einen bzw. anderen Seite des Hochdruckkreises verbunden werden, was einem Umschalten zwischen dem normalen Differenzvolumenausgleich und der Schwimmstellung des Differentialzylinders entspricht. Hierbei ergibt sich die Ventilstellung der Rückschlagventile entsprechend der Bewegungsrichtung sowie der anliegenden Last und damit den Druckverhältnissen im Zylinder. So wird eine sichere Möglichkeit geschaffen, die Betriebszustände zu wechseln, wobei die Gefahr von Druckstößen minimiert wird.Thus, it can be provided that the control device for regulating the pump delivery rate is designed electronically. The delivery rate of adjustable pumps is usually controlled electro-hydraulically. It is therefore particularly advantageous if this control is applied in an integrated manner together with the control device of the check valves, so that safe and precise regulation of the complete circuit behavior is possible. This can prevent, for example, that the pump requests a volume flow when the check valves are unlocked, which would then be briefly closed by the unlocked check valves. A further embodiment of the hydraulic system provides that the electronic African control device for controlling the check valves has an electro-hydraulic 4/2-way valve. With such a valve, the unblocking connection of the check valves can be alternately connected to one or the other side of the high-pressure circuit, which corresponds to a switchover between the normal differential volume compensation and the floating position of the differential cylinder. This results in the valve position of the check valves according to the direction of movement and the applied load and thus the pressure conditions in the cylinder. This creates a safe way of changing operating states, while minimizing the risk of pressure surges.
Alternativ können auch zwei elektrohydraulische 3/2- Wegeventile verwendet werden.Alternatively, two electro-hydraulic 3/2-way valves can be used.
Eine besondere Ausgestaltung des Hydrauliksystems sieht vor, dass an wenigstens einem Anschluss des Differentialzylinders ein steuerbares Absperrventil vorgesehen ist. Durch ein solches Absperrventil läßt sich ein Anschluss des Zylinders leckfrei absperren, was insbesondere zur Realisierung einer Haltefunktion sinnvoll ist. Dabei wird der Zylinder durch den Volumenstrom der Pumpe in eine bestimmte Position gebracht und anschließend der Hochdruck- anschluss des Differentialzylinders abgesperrt, so dass dieser in seiner Position verbleibt, auch ohne dass die Pumpe den Druck aufrechterhält. Wenn am zweiten Anschluss des Differentialzylinders ebenfalls ein Absperrventil vorgesehen ist, kann der Zylinder komplett vom Hydraulikkreis getrennt werden, wobei er in seiner Position verbleibt. Durch die Pumpe und den angeschlossenen Hydraulikkreis kann in diesem Zustand ein weiterer Differentialzylinder bedient werden, der dann ebenfalls über Absperrventile vom Kreis trennbar ist. Hierdurch läßt sich einfach und kostengünstig eine weitere Funktion in der Arbeitsmaschine realisieren, die alternativ von den weiteren vorhandenen Zylindern betrieben werden kann.A special embodiment of the hydraulic system provides that a controllable shut-off valve is provided on at least one connection of the differential cylinder. Such a shut-off valve allows a connection of the cylinder to be shut off without leakage, which is particularly useful for realizing a holding function. The volume flow of the pump brings the cylinder into a certain position and then the high-pressure connection of the differential cylinder is shut off, so that it remains in its position without the pump maintaining the pressure. If a shut-off valve is also provided on the second connection of the differential cylinder, the cylinder can be completely separated from the hydraulic circuit, while remaining in its position. In this state, the pump and the connected hydraulic circuit can be used to operate a further differential cylinder, which can then also be separated from the circuit via shut-off valves. This allows a further function in the Realize work machine that can alternatively be operated by the other existing cylinders.
Vorteilhaft kann es sein, dass das Niederdrucksystem als Speicherladeschaltung mit einem Speicherladeventil, einer Pumpe mit Hydraulikspeicher und einem Druckbegrenzungsventil ausgebildet ist. Eine solche Ausgestaltung der Niederdruckseite zeichnet sich durch eine besonders hohe Energieeffizienz aus. Die Pumpe fordert nur dann in das Niederdrucksystem, wenn ein eingestellter Minimaldruckwert unterschritten wird. Die Speicherladeschaltung sorgt für die Einhaltung eines Niederdruckniveaus zwischen einstellbaren Grenzwerten. Ein solches Niederdrucksystem kann zentral für das gesamte Hydrauliksystem ausgebildet sein und sämtliche erfindungsgemäßen verdrängergesteuerten Hydraulikkreise versorgen.It can be advantageous that the low-pressure system is designed as an accumulator charging circuit with an accumulator charging valve, a pump with hydraulic accumulator and a pressure limiting valve. Such a design of the low pressure side is characterized by a particularly high energy efficiency. The pump only pushes into the low-pressure system when the pressure drops below a set minimum. The accumulator charging circuit ensures compliance with a low pressure level between adjustable limit values. Such a low-pressure system can be designed centrally for the entire hydraulic system and can supply all displacement-controlled hydraulic circuits according to the invention.
Eine weitere Ausgestaltung des erfindungsgemäßen Hydrauliksystems ist dadurch gekennzeichnet, dass das steuerbare Absperrventil als Sitzventil mit 3/2- Wege- Vorsteuerung ausgebildet ist. Außerdem kann es sinnvoll sein, dass das steuerbare Absperrventil als Stetigventil ausgebildet ist. Mit einem solchen Ventil läßt sich einfach die entsprechende Sperrfunktion des Anschlusses realisieren, ohne dass ein zu ruckartiges Öffnen bzw. Schließen des Ventils vorkommt. Dadurch lassen sich unerwünschte Druckspitzen im System unterbinden.A further embodiment of the hydraulic system according to the invention is characterized in that the controllable shut-off valve is designed as a seat valve with 3/2-way pilot control. It can also make sense for the controllable shut-off valve to be designed as a continuous valve. With such a valve, the corresponding blocking function of the connection can be easily implemented without the valve opening or closing too suddenly. This prevents unwanted pressure peaks in the system.
Vorteilhaft kann es sein, dass weitere ggf. stetig steuerbare Absperrventile zur alternativen und/oder gleichzeitigen Ansteuerung weiterer Differentialzylinder vorgesehen sind. Wie oben beschrieben, lassen sich durch solche Ventile weitere Funktionen am selben Hochdruckkreis realisieren, wobei diese immer alternativ zueinander in Betrieb sind. Die Absperrventile werden dabei so geschaltet, dass die Pumpe mit den zugehörigen Schutz- und Ausgleichsventilen jeweils an einem Differentialzylinder bzw. mehreren parallel geschalteten derselben Funktion angeschlossen ist und diese mit Druckmittel versorgt. Eine weitere Ausgestaltung der Erfindung sieht vor, dass am Hochdruckkeis Anschlüsse für ein passives Schwingungsdämpfüngssystem vorgesehen sind. Solche Dämpfungssysteme bestehen aus einer Hydraulikschaltung mit Speicher, die die beispielsweise beim Fahren mit angehobener Last auftretenden Schwingungen des Arbeitsgerätes mindert. Dazu wird das Schwingungsdämpfüngssystem direkt an mindestens einem Anschluss an einer Seite des Hochdruckkreises angeschlossen und ist zu- und abschaltbar, um in gewünschten Betriebssituationen die unerwünschten Schwingungszustände zu unterdrük- ken.It can be advantageous that further shut-off valves, which may be continuously controllable, are provided for alternative and / or simultaneous actuation of further differential cylinders. As described above, further functions can be implemented on the same high-pressure circuit by means of such valves, whereby these are always operated alternatively to one another. The shut-off valves are switched so that the pump with the associated protection and compensation valves is each connected to a differential cylinder or a plurality of the same function connected in parallel and supplies them with pressure medium. A further embodiment of the invention provides that connections for a passive vibration damping system are provided on the high-pressure circuit. Such damping systems consist of a hydraulic circuit with an accumulator, which reduces the vibrations of the implement, for example when driving with a raised load. For this purpose, the vibration damping system is connected directly to at least one connection on one side of the high-pressure circuit and can be switched on and off in order to suppress the undesired vibration states in desired operating situations.
In einer Ausgestaltung der Erfindung ist vorgesehen, dass die elektronische Steuerungsvorrichtung, die steuerbaren Ventile und ggf. weitere vorhandene hydraulische Systemkomponenten mit der verstellbaren Pumpe als integriertes Bauteil ausgebildet sind.In one embodiment of the invention, it is provided that the electronic control device, the controllable valves and, if appropriate, other hydraulic system components present are designed with the adjustable pump as an integrated component.
Eine solche Integration der Pumpe mit einer Reihe der Ventile und der Steuerung bietet den Vorteil einer äußerst kompakten Bauweise, was sinnvoll sein kann, da diese Komponenten für jede durch Differentialzylindersysteme angetriebene Hydraulikfunktion nötig sind. Durch die Integration vermindert sich die Zahl der Einzelkomponenten, wird die Komplexität des Gesamsy- stems reduziert, der Installationsaufwand sinkt und damit sinken die Kosten eines solchen Systems im Vergleich zu herkömmlichen Systemen. Vorteilhaft für die Steuerungs- und Regelungskonzepte kann es sein, dass Sensoren zur Erfassung der Systemzustände, insbesondere der Differentialzylinder- Position und der Hydraulikdrücke, vorgesehen sind. Außerdem kann es sinnvoll sein, dass eine elektronische Regelungseinrich- tung zur Regelung der steuerbaren Systemkomponenten abhängig vom gemessenen Systemzustand und Benutzervorgaben vorgesehen ist. Durch Messen der Systemzustände und Verarbeiten der gewonnenen Daten in einer Steuerungsvorrichtung lassen sich die Linearzylinder in einem geschlossenen Regelkreis betreiben, was die Positioniergenauigkeit und die Stabilität des Systems deutlich verbessert.Such an integration of the pump with a number of the valves and the control offers the advantage of an extremely compact design, which can be useful since these components are necessary for every hydraulic function driven by differential cylinder systems. The integration reduces the number of individual components, the complexity of the overall system is reduced, the installation effort is reduced and the costs of such a system are reduced in comparison to conventional systems. It can be advantageous for the control and regulation concepts that sensors are provided for detecting the system states, in particular the differential cylinder position and the hydraulic pressures. It may also make sense for an electronic control device device for controlling the controllable system components depending on the measured system state and user specifications. By measuring the system states and processing the data obtained in a control device, the linear cylinders can be operated in a closed control loop, which significantly improves the positioning accuracy and the stability of the system.
Das erfindungsgemäße Antriebssystem läßt sich auch gesteuert, d.h. in offener Wirkungskette betreiben.The drive system according to the invention can also be controlled, i.e. operate in an open chain of effects.
Die Erfindung richtet sich außerdem auf eine mobile Arbeitsmaschine mit wenigstens einem Hydrauliksystem, wie im vorangegangenen beschrieben ist. In einer Ausgestaltung einer solchen Arbeitsmaschine sind mehrere Hochdruckkreise mit einem gemeinsamen Niederdruckkreis vorgesehen. Dieser hat, wie bereits erläutert, den Vorteil der zusätzlichen Kostenersparnis, da ein einziger Niederdruckkreis mit einer Pumpe und den weiteren Komponenten zur Versorgung aller erfindungsgemäßen Hydrauliksysteme ausreicht.The invention is also directed to a mobile work machine with at least one hydraulic system, as described in the preceding. In one embodiment of such a working machine, a plurality of high-pressure circuits with a common low-pressure circuit are provided. As already explained, this has the advantage of additional cost savings, since a single low-pressure circuit with a pump and the further components is sufficient to supply all the hydraulic systems according to the invention.
Die Erfindung ist nachstehend anhand der Zeichnungen beispielhaft näher erläutert. Diese zeigen in: Fig. 1 : eine schematische Grundschaltung eines Hydrauliksystems nach der Erfindung, Fig. 2: eine Schaltung eines erfindungsgemäßen Hydrauliksystems in einer erweiterten Ausführung,The invention is explained in more detail below using the drawings as an example. These show in: FIG. 1: a schematic basic circuit of a hydraulic system according to the invention, FIG. 2: a circuit of a hydraulic system according to the invention in an expanded version,
Fig. 3 eine weitere Ausführung, Fig. 4 noch eine weitere Ausführung, Fig. 5 ein Gesamtsystem für eine mobile Arbeitsmaschine und in Fig. 6 ein weiteres Gesamtsystem für eine mobile Arbeitsma- schine.3 shows a further embodiment, FIG. 4 shows yet another embodiment, FIG. 5 shows an overall system for a mobile working machine and in FIG. 6 shows another overall system for a mobile working machine machine.
Ein allgemein mit 1 bezeichnetes Hydrauliksystem dient zur Ansteuerung eines hydraulischen Differentialzylinders 2.A hydraulic system, generally designated 1, is used to control a hydraulic differential cylinder 2.
Eine Pumpe 3 mit verstellbarem Fördervolumen und Umkehr der Förderrichtung ist über zwei Leitungen 4 und 5 mit den beiden Anschlüssen des Differentialzylinders 2 verbunden.A pump 3 with an adjustable delivery volume and reversal of the delivery direction is connected to the two connections of the differential cylinder 2 via two lines 4 and 5.
Ein von der Pumpe 3 geforderter Volumenstrom in die eine oder andere Richtung führt zu einer Bewegung des Kolbens 6 des Differentialzylinders 2. Da die beiden Kammern des hydraulischen Differentialzylinders 2 bedingt durch die asymmetrische Gestaltung des Kolbens 6 bzw. der Kolbenstange ein unterschiedliches Volumen besitzen, wird bei einer Bewegung des Kolbens 6 eine andere Menge des Druckmittels auf der einen Seite abgegeben als von der anderen Seite aufgenommen wird. Um diesen Differenzvolumenstrom im eigentlich geschlossenen Kreislauf zwischen Pumpe 3 und Zylinder 2 auszugleichen, steht dieser Hochdruckkreis über zwei entsperrbare Rückschlagventile 7 und 8 mit einem Niederdrucksystem 9 in Verbindung. Im stationären Fall ist durch den höheren Druck, in einer der beiden Leitungen 4 bzw. 5 das gegenüberliegende Rückschlagventil 7 oder 8 zwischen Hochdruckleitung und Niederdrucksystem 9 entsperrt, so dass immer die Niederdruckseite des hydraulischen Differentialzylinders 2 mit dem Niederdrucksystem 9 verbunden ist. Wird von der verstellbaren Pumpe 3 ein Volumenstrom zum Differentialzylinder 2 gefördert, führt dies zu einer Bewegung des Kolbens 6 des Differentialzylinders 2. Der von der Bewegungsrichtung abhängige positive oder negative Differenzvolumenstrom wird dabei über eines der beiden Rückschlagventile 7 oder 8 gegenüber dem Niederdrucksystem 9 ausgeglichen. Für diese Grundstellung ist ein mit den Rückschlagventilen 7 und 8 verbundenes elektrohydraulisches 4/2- Wegeventil 10 so geschaltet, dass die Entsperranschlüsse der Rückschlagventile 7 und 8 jeweils mit dem gegenüberliegenden Teil des Hochdruckkreises verbunden sind. Dadurch ist auch bei einem Wechsel des Belastungszustandes am Differentialzylinder 2 eine Übernahme des Differenzvolumenstromausgleiches durch das jeweils andere Ventil ohne Druckspitzen gewährleistet, da die Rückschlagventile 7 und 8 immer genau dann schalten, wenn auf beiden Seiten des Rückschlagventils etwa Niederdruck anliegt.A volume flow demanded by the pump 3 in one direction or the other leads to a movement of the piston 6 of the differential cylinder 2. Since the two chambers of the hydraulic differential cylinder 2 have a different volume due to the asymmetrical design of the piston 6 or the piston rod when the piston 6 moves, a different amount of pressure medium is emitted on one side than is absorbed by the other side. In order to compensate for this differential volume flow in the actually closed circuit between pump 3 and cylinder 2, this high-pressure circuit is connected to a low-pressure system 9 via two unlockable check valves 7 and 8. In the stationary case, the opposite check valve 7 or 8 between the high-pressure line and the low-pressure system 9 is unlocked in one of the two lines 4 and 5, so that the low-pressure side of the hydraulic differential cylinder 2 is always connected to the low-pressure system 9. If a volume flow is conveyed to the differential cylinder 2 by the adjustable pump 3, this leads to a movement of the piston 6 of the differential cylinder 2. The positive or negative differential volume flow, which is dependent on the direction of movement, is compensated via one of the two check valves 7 or 8 with respect to the low-pressure system 9. For this basic position is one with the check valves 7 and 8 connected electro-hydraulic 4/2-way valve 10 switched so that the unblocking connections of the check valves 7 and 8 are each connected to the opposite part of the high pressure circuit. As a result, even when the load state on the differential cylinder 2 changes, an assumption of the differential volume flow compensation is ensured by the other valve without pressure peaks, since the check valves 7 and 8 always switch exactly when low pressure is present on both sides of the check valve.
Das elektronisch steuerbare 4/2- Wegeventil 10 dient auch zur Realisierung einer Schwimmstellungsfunktion. Wird das Ventil 10 umgeschaltet (Schwimmstellungsfunktion), werden die Entsperranschlüsse der Rückschlagventile 7 und 8 nicht mehr mit der gegenüberliegenden, sondern mit der in ihrer Durchlassrichtung liegenden Seite verbunden. Dadurch öffnen sich die Rückschlagventile 7 bzw. 8, sobald in einer der beiden Leitungen 4 oder 5 ein Druck anliegt, der geringfügig höher ist als der Niederdruck im Niederdrucksystem 9. Damit kann sich der Kolben 6 im Differentialzylinder 2 frei bewegen. Sinnvollerweise ist bei einem Schalten des 4/2- Wegeventils 10 in die Schwimmstellung die Pumpe 3 so eingestellt, dass sie keinen Volumenstrom fordert, da dieser ebenfalls durch den Quasi- Kurzschluss durch die Rückschlagventile 7 bzw. 8 ausgeglichen werden würde.The electronically controllable 4/2-way valve 10 also serves to implement a floating position function. If the valve 10 is switched over (floating position function), the unblocking connections of the check valves 7 and 8 are no longer connected to the opposite side, but to the side lying in their passage direction. As a result, the check valves 7 and 8 open as soon as a pressure is present in one of the two lines 4 or 5 which is slightly higher than the low pressure in the low-pressure system 9. The piston 6 can thus move freely in the differential cylinder 2. When the 4/2-way valve 10 is switched to the floating position, the pump 3 is expediently set such that it does not require a volume flow, since this would also be compensated for by the quasi-short circuit through the check valves 7 and 8.
An einem Anschluss des Differentialzylinders 2 ist ein steuerbares Absperrventil 11 vorgesehen. Damit kann diese Seite des Differentialzylinders 2 leck- frei abgesperrt werden, wodurch der Kolben 6 in dieser Position fixiert und eine daran befindliche Last gehalten wird. In der Regel ist dies die stärker belastete Kolbenseite des Differentialzylinders 2. Im System befinden sich Drucksensoren 12, die zur Erfassung der Zustände in den Hochdruckleitungen dienen. Am hydraulischen Differentialzylinder 2 befindet sich ein Wegsensor 13 oder ein Winkelsensor in der Kinematik der Arbeitsausrüstung, der die Kolbenstellung erfasst. Die Signale der Sensoren 12 und 13 werden von einer elektronischen Regelungseinrichtung 14 zusammen mit durch entsprechende Bedienelemente 15 vorgegebenen Benutzerwünschen verarbeitet und daraus die entsprechenden Stellgröße ermittelt, die an die elektronische Steuervorrichtung 16 weitergeleitet wird. Diese steuert dann die verstellbare Pumpe 3 in ihrem Verdrängungsvolumen und damit den geförderten Volumenstrom sowie ggf. die Schaltzustände der elektronischen Ventile 10 bzw. 11.A controllable shut-off valve 11 is provided on a connection of the differential cylinder 2. This side of the differential cylinder 2 can thus be shut off without leakage, as a result of which the piston 6 is fixed in this position and a load located thereon is held. As a rule, this is the more heavily loaded piston side of the differential cylinder 2. There are pressure sensors 12 in the system which are used to detect the states in serve the high pressure lines. A displacement sensor 13 or an angle sensor in the kinematics of the work equipment, which detects the piston position, is located on the hydraulic differential cylinder 2. The signals from the sensors 12 and 13 are processed by an electronic control device 14 together with user requests specified by corresponding control elements 15, and the corresponding manipulated variable is determined therefrom, which is transmitted to the electronic control device 16. This then controls the adjustable pump 3 in its displacement volume and thus the volume flow conveyed as well as, if applicable, the switching states of the electronic valves 10 and 11.
Eine Erweiterung dieses Grundprinzips ist in Fig. 2 näher dargestellt. Dabei wird wieder ein hydraulischer Differentialzylinder 2 im wesentlichen direkt mit einer verstellbaren Pumpe 3 verbunden. Der Differenzvolumenstrom wird bei Förderung durch die zwei entsperrbaren Rückschlagventile 7 und 8 ausgeglichen, deren Entsperranschlüsse von einem elektrohydraulischen 4/2- Wegeventil 10 jeweils wechselweise mit den gegenüberliegenden bzw. anliegenden Seiten des Hochdruckkreises verbunden werden. Zum Schutz des Systems vor Überdrücken sind zwei Hochdruckabsicherungen 27 vorgesehen. Die integrierte elektronische Regelungseinrichtung 14 regelt die Ansteuerung der einzelnen Komponenten, wie der verstellbaren Pumpe 3 unter Berücksichtigung der gemessenen Systemzustände und der Benutzervorgaben 15.An extension of this basic principle is shown in more detail in FIG. 2. Again, a hydraulic differential cylinder 2 is essentially connected directly to an adjustable pump 3. The differential volume flow is compensated for during delivery by the two unblockable check valves 7 and 8, the unblocking connections of which are alternately connected to the opposite or adjacent sides of the high pressure circuit by an electrohydraulic 4/2-way valve 10. To protect the system from overpressures, two high-pressure safeguards 27 are provided. The integrated electronic control device 14 controls the control of the individual components, such as the adjustable pump 3, taking into account the measured system states and the user specifications 15.
Zusätzlich zu dem elektronisch steuerbaren Absperrventil 11 ist die zweite Seite des Differentialzylinders 2 ebenfalls durch ein elektronisch steuerbares Absperrventil 17 absperrbar. Zusätzlich ist über zwei weitere elektronisch steuerbare Absperrventile 18 ein zusätzlicher Differentialzylinder 19 am Hochdruckkreis angeschlossen.In addition to the electronically controllable shut-off valve 11, the second side of the differential cylinder 2 can also be shut off by an electronically controllable shut-off valve 17. In addition, an additional differential cylinder 19 is located on two further electronically controllable shut-off valves 18 High pressure circuit connected.
Im Betrieb des zweiten Differentialzylinders 19 wird der erste Differentialzylinder 2 durch die beiden Absperrventile 11 und 17 vom Hydraulikkreis getrennt und dadurch in seiner Position gehalten. Anschließend werden die beiden Absperrventile 18 geöffnet, so dass ein von der Pumpe 3 geforderter Volumenstrom den zweiten Differentialzylinder 19 bewegt. Die auftretenden Differenzvolumina werden wieder über die beiden entsperrbaren Rückschlagventile 7 und 8 in den Niederdruckkreis 9 ausgeglichen. Die steuerbaren Absperrventile 11, 17 und 18 können in einigen Anwendungsfallen auch als Stetigventile ausgebildet sein, so dass diese in besonderen Situationen im Betrieb stetig angesteuert werden können und damit ein gleichzeitiger Betrieb der beiden Differentialzylinder 2 und 19 möglich ist.In the operation of the second differential cylinder 19, the first differential cylinder 2 is separated from the hydraulic circuit by the two shut-off valves 11 and 17 and is thereby held in its position. Then the two shut-off valves 18 are opened so that a volume flow required by the pump 3 moves the second differential cylinder 19. The differential volumes that occur are compensated again via the two unlockable check valves 7 and 8 in the low-pressure circuit 9. The controllable shut-off valves 11, 17 and 18 can, in some applications, also be designed as continuous valves, so that they can be controlled continuously in special situations during operation and thus simultaneous operation of the two differential cylinders 2 and 19 is possible.
Der Niederdruck im Niederdrucksystem 9 wird mit einer Speicherladeschaltung realisiert. Dabei findet eine Konstantpumpe 20 mit einem Speicherladeventil 21 und einem hydropneumatischen Speicher 22 Verwendung. Ein Überdruckventil 23 schützt die Anlage vor Überlast. Dabei sorgt das Speicherladeventil 21 dafür, dass die Konstantpumpe 20 nur dann in das Niederdrucksystem 9 fördert, wenn ein eingestellter Minimalwert des Druckes unterschritten wird. Da für den reinen Druckerhalt das Speicherladeventil 21 sorgt, ist die Anlage energieeffizient zu realisieren. Aber auch andere Kombinationen zur Realisierung des Niederdrucksystems 9 sind möglich, beispielsweise über eine einfache Kombination von Konstantpumpe, Speicher und Druckbegrenzungsventil oder mittels einer Verstellpumpe. Dieser Niederdruck wird auch hinter dem Anschluss 24 der verstellbaren Pumpe 3 dazu benutzt, das elektrohydraulische Verstellsystem dieser Pumpe zu betreiben. Die Anschlüsse 25 und 26 dienen zum Anschluss eines passiven Schwingungs- Dämpfersy- stems am Differentialzylinder 2.The low pressure in the low pressure system 9 is realized with an accumulator charging circuit. Here, a constant pump 20 with an accumulator charging valve 21 and a hydropneumatic accumulator 22 is used. A pressure relief valve 23 protects the system against overload. The accumulator loading valve 21 ensures that the constant pump 20 only delivers into the low-pressure system 9 when the pressure falls below a set minimum value. Since the accumulator charging valve 21 ensures pure pressure maintenance, the system can be implemented in an energy-efficient manner. However, other combinations for realizing the low pressure system 9 are also possible, for example via a simple combination of a constant pump, accumulator and pressure relief valve or by means of a variable displacement pump. This low pressure is also used behind the connection 24 of the adjustable pump 3 to operate the electro-hydraulic adjustment system of this pump. The connections 25 and 26 are used to connect a passive vibration damper system. stems on the differential cylinder 2.
In Fig. 3 ist eine erste Abwandlung des Grundprinzips dargestellt, in welchem anstelle des elektrohydraulischen 4/2- Wegeventils zwei 3/2- Wegeventile 28, 29 eingesetzt sind, um die Schwimmstellung durch ein Umschalten der Entsperranschlüsse der entsperrbaren Rückschlagventile 7, 8 zu realisieren. Weiterhin wird der Niederdruck nun über eine Konstantpumpe 20 mit einem hydropneumatischen Speicher 22 und einem Überdruckventil 23 aufgeprägt. In Fig. 4 ist eine weitere Abwandlung des Grundprinzips dargestellt. Die Schwimmstellung wird über einen Bypass durch zwei Ventile 30, 31 realisiert, d.h. bei Bestromung der Ventile sind die beiden Zylinderkammern zum Niederdruck verbunden und der Differentialzylinder 2 kann sich frei bewegen. Der Niederdruck wird hier über eine Verstellpumpe 20' mit einem hydropneumatischen Speicher 22 aufgeprägt und über ein Überdruckventil 23 abgesichert. Zusätzlich zeigt dieses Schema auch eine andere Möglichkeit, die dritte Funktion mit der Pumpe 3 zu versorgen. Zwei 3/2- Wegeventile 32, 33 an Anschlüssen 34, 35 können die Pumpe 3 bei Aktivierung einfach zur dritten Funktion umschalten.3 shows a first modification of the basic principle, in which two 3/2-way valves 28, 29 are used instead of the electrohydraulic 4/2-way valve in order to realize the floating position by switching over the unlocking connections of the unlockable check valves 7, 8 , Furthermore, the low pressure is now applied via a constant pump 20 with a hydropneumatic accumulator 22 and a pressure relief valve 23. 4 shows a further modification of the basic principle. The floating position is achieved via a bypass by two valves 30, 31, i.e. when the valves are energized, the two cylinder chambers are connected to the low pressure and the differential cylinder 2 can move freely. The low pressure is impressed here via a variable displacement pump 20 'with a hydropneumatic accumulator 22 and secured by a pressure relief valve 23. In addition, this diagram also shows another possibility of supplying the third function with the pump 3. Two 3/2-way valves 32, 33 at connections 34, 35 can simply switch the pump 3 to the third function when activated.
Fig. 5 zeigt ein Gesamtsystem für eine mobile Arbeitmaschine (hier Radlader) mit verdrängergesteuerter Arbeitshydraulik nach dem vorbeschriebenem verdrängergesteuerten Linearantriebsprinzip (valveless- Prinzip) und hydrostatischem Fahrantrieb. Die einfache Kopplung mehrerer Aktuatoren über den Niederdruck sowie mit dem hydrostatischen Fahrantrieb reduziert den Systemaufwand nochmals.5 shows an overall system for a mobile working machine (here wheel loader) with displacement-controlled working hydraulics according to the previously described displacement-controlled linear drive principle (valveless principle) and hydrostatic travel drive. The simple coupling of several actuators via the low pressure and with the hydrostatic travel drive further reduces the system effort.
In Fig. 6 ist ein weiteres Gesamtsystem (hier Radlader) abgebildet, wobei hier ein hydrostatischer Fahrantrieb im 2- Motor- Konzept mit abkoppelbarem Verstellmotor vorliegt und der Niederdruck für alle verdrängergesteuerten Hauptfunktionen durch den Rücklauf des hydrostatischen Lüfters und einen Speicher aufgeprägt wird. Ein Speicherladeventil verbindet den Rücklauf des Lüfters nur dann mit dem Niederdruck, wenn Niederdruckvolumenstrom benötigt wird.6 shows a further overall system (here wheel loader), a hydrostatic travel drive in the 2-motor concept with a detachable adjustment motor being present and the low pressure for all displacement-controlled ones Main functions are impressed by the return of the hydrostatic fan and a memory. An accumulator charging valve connects the return of the fan to the low pressure only when low pressure volume flow is required.
Durch die elektrohydraulische Steuerung der verstellbaren Pumpe 3 können alle weiteren Funktionalitäten, die softwaretechnisch hinterlegt sind, realisiert werden, wie etwa Gabelparallelführung, Rückführautomatik, Hubendabschaltung, variabler Schaufelanschlag, variable Zylinderdämpfung (Soft- Staub), Schüttel- bzw. Verteilfunktionen an der Schaufel für landtechnische Einsätze usw. Die jeweilige Verstellpumpe wird dabei direkt über die Steuerung des Gerätes angesprochen. Dabei kann der verdrängergesteuerte Aktua- tor sowohl in Positions- als auch Geschwindigeitsregelung (Beispiel: Parallele Werkzeugführung) oder auch gesteuert im offenen Regelkreis betrieben werden. Die Steuerung verarbeitet dabei als Eingangssignal den Wunsch des Bedieners (beispielsweise über einen Joystick).The electro-hydraulic control of the adjustable pump 3 can be used to implement all other functionalities that are stored in the software, such as fork parallel guidance, automatic feedback control, end of stroke shutdown, variable blade stop, variable cylinder damping (soft dust), shaking or distribution functions on the blade for agricultural engineering Inserts etc. The respective variable pump is addressed directly via the control of the device. The displacement-controlled actuator can be operated both in position and speed control (example: parallel tool guidance) or in a controlled manner in an open control loop. The control processes the operator's request as an input signal (for example via a joystick).
Natürlich ist die Erfindung nicht auf das vorstehende Beispiel beschränkt, sondern in vielfältiger Hinsicht abänderbar, ohne den Grundgedanken zu verlassen. So sind vielfaltige Bauformen für die verwendeten Pumpen, Ventile usw. denkbar, solange sie die beanspruchten Funktionen erfüllen. Dabei ist die Auftrennung der Funktionen einzelner Ventile auf mehrere Komponenten denkbar und unter Umständen sinnvoll. Auch ist es möglich, weitere Zylinder über Absperrventile an demselben Hochdrucksystem zu betreiben. BezugszeichenlisteOf course, the invention is not limited to the example above, but can be modified in many ways without departing from the basic idea. A variety of designs for the pumps, valves, etc. used are conceivable as long as they fulfill the claimed functions. The separation of the functions of individual valves into several components is conceivable and may make sense. It is also possible to operate additional cylinders with shut-off valves on the same high-pressure system. LIST OF REFERENCE NUMBERS
1 Hydrauliksystem1 hydraulic system
2 Differentialzylinder2 differential cylinders
3 Pumpe3 pump
4 Leitung4 line
5 Leitung5 line
6 Kolben6 pistons
7 Rückschlagventil7 check valve
8 Rückschlagventil8 check valve
9 Niederdrucksystem9 low pressure system
10 4/2- Wegeventil10 4/2-way valve
11 steuerbares Absperrventil11 controllable shut-off valve
12 Drucksensor12 pressure sensor
13 Wegsensor13 displacement sensor
14 elektronische Regelungseinrichtung14 electronic control device
15 Bedienelement15 control element
16 elektronische Steuerungsvorrichtung16 electronic control device
17 Absperrventil17 shut-off valve
18 Absperrventil18 shut-off valve
19 Differentialzylinder19 differential cylinders
20 Konstantpumpe20 constant pump
20' Verstellpumpe20 'variable displacement pump
21 Speicherladeventil21 accumulator charging valve
22 hydropneumatischer Speicher22 hydropneumatic accumulator
23 Überdruckventil Anschluss23 pressure relief valve connection
Anschlussconnection
Anschlussconnection
HochdruckabsicherungHigh pressure protection
3/2- Wegeventil3/2-way valve
3/2- Wegeventil3/2-way valve
VentilValve
VentilValve
3/2- Wegeventil3/2-way valve
3/2- Wegeventil3/2-way valve
Anschlussconnection
Anschluss connection

Claims

Patentansprüche claims
1. Hydrauliksystem für verdrängergesteuerte Linearantriebe, insbesondere für mobile Arbeitsmaschinen mit wenigstens einem Differentialzylinder, wenigstens einem Hochdruckkreis, der wenigstens eine Pumpe mit verstellbarer Fördermenge und Umkehr der Förderrichtung beinhaltet und durch wenigstens zwei entsperrbare Rückschlagventile mit einem Niederdrucksystem verbunden ist, dadurch gekennzeichnet, dass die Rückschlagventile (7,8) mit einer elektronischen Steuerungsvorrichtung (16) derart verbunden sind, dass ein schaltstoßfreies Umschalten zwischen einem Ein- bzw. Ausfahren des Differentialzylinders (2) und einer Schwimmstellung möglich ist.1.Hydraulic system for displacement-controlled linear drives, in particular for mobile machines with at least one differential cylinder, at least one high-pressure circuit, which contains at least one pump with adjustable delivery volume and reversal of the direction of delivery and is connected to a low-pressure system by at least two unlockable check valves, characterized in that the check valves (7,8) are connected to an electronic control device (16) in such a way that switching-shock-free switching between retracting and extending the differential cylinder (2) and a floating position is possible.
2. Hydrauliksystem nach Anspruch 1, dadurch gekennzeichnet, dass die elektronische Steuerungsvorrichtung (16) zur Regelung der Pumpen- Fördermenge und Förderrichtung ausgebildet ist.2. Hydraulic system according to claim 1, characterized in that the electronic control device (16) is designed to regulate the pump delivery rate and delivery direction.
3. Hydrauliksystem nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass zur Ansteuerung der Rückschlagventile (7,8) ein elektrohydraulisches 4/2- Wegeventil (10) vorgesehen ist.3. Hydraulic system according to claim 1 or 2, characterized in that an electro-hydraulic 4/2-way valve (10) is provided for controlling the check valves (7, 8).
4. Hydrauliksystem nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass zur Ansteuerung der Rückschlagventile (7,8) zwei elektrohydraulische 3/2- Wegeventile (28,29) vorgesehen sind. 4. Hydraulic system according to claim 1 or 2, characterized in that two electro-hydraulic 3/2-way valves (28, 29) are provided for controlling the check valves (7, 8).
5. Hydrauliksystem nach einem der vorangehenden Ansprüche, dadurch ge- kennzeichnet, dass an wenigstens einem Anschluss des Differentialzylinders (2) ein steuerbares Absperrventil (11) vorgesehen ist.5. Hydraulic system according to one of the preceding claims, characterized in that a controllable shut-off valve (11) is provided on at least one connection of the differential cylinder (2).
6. Hydrauliksystem nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass das Niederdrucksystem (9) als Speicherladeschaltung mit einem Speicherladeventil (21), einer Pumpe (20) mit Hydraulikspeicher (22) und einem Druckbegrenzungsventil (23) ausgebildet ist.6. Hydraulic system according to one of the preceding claims, characterized in that the low-pressure system (9) is designed as an accumulator charging circuit with an accumulator charging valve (21), a pump (20) with hydraulic accumulator (22) and a pressure relief valve (23).
7. Hydrauliksystem nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass das Niederdrucksystem (9) mit einer Pumpe (20) mit Hydraulikspeicher (22) und einem Druckbegrenzungsventil (23) ausgebildet ist.7. Hydraulic system according to one of the preceding claims, characterized in that the low pressure system (9) with a pump (20) with hydraulic accumulator (22) and a pressure relief valve (23) is formed.
8. Hydrauliksystem nach Anspruch 4, dadurch gekennzeichnet, dass das steuerbare Absperrventil (11) als Sitzventil mit 3/2- Wege- Vorsteuerung ausgebildet ist.8. Hydraulic system according to claim 4, characterized in that the controllable shut-off valve (11) is designed as a seat valve with 3/2-way pilot control.
9. Hydrauliksystem nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass das steuerbare Absperrventil (11) als Stetigventil ausgebildet ist.9. Hydraulic system according to one of the preceding claims, characterized in that the controllable shut-off valve (11) is designed as a continuous valve.
lO.Hydrauliksystem nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass weitere ggf. stetig steuerbare Absperrventile (17,18) zur alternativen und/oder gleichzeitigen Ansteuerung weiterer Differentialzylinder (19) vorgesehen sind. 10. Hydraulic system according to one of the preceding claims, characterized in that further, possibly continuously controllable shut-off valves (17, 18) are provided for the alternative and / or simultaneous actuation of further differential cylinders (19).
11. Hydrauliksystem nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass am Hochdruckkreis Anschlüsse (25,26) für ein passives Schwingungsdämpfungssystem vorgesehen sind.11. Hydraulic system according to one of the preceding claims, characterized in that connections (25, 26) are provided on the high pressure circuit for a passive vibration damping system.
12.Hydrauliksystem nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die elektronische Steuerungsvorrichtung (16), die steuerbaren Ventile (10,11) und ggf. weitere vorhandene hydraulische Systemkomponenten mit der verstellbaren Pumpe (3) als integriertes Bauteil ausgebildet sind.12.Hydraulic system according to one of the preceding claims, characterized in that the electronic control device (16), the controllable valves (10, 11) and possibly other hydraulic system components with the adjustable pump (3) are designed as an integrated component.
13. Hydrauliksystem nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass Sensoren (12,13) zur Erfassung der Systemzustände, insbesondere der Differentialzylinder- Position und der Hydraulikdrücke vorgesehen sind.13. Hydraulic system according to one of the preceding claims, characterized in that sensors (12, 13) are provided for detecting the system states, in particular the differential cylinder position and the hydraulic pressures.
14.Hydrauliksystem nach Anspruch 13, dadurch gekennzeichnet, dass eine elektronische Regelungseinrichtung (14) zur Regelung der steuerbaren Systemkomponenten abhängig vom gemessenen Systemzustand und Benutzervorgaben vorgesehen ist.14. Hydraulic system according to claim 13, characterized in that an electronic control device (14) is provided for controlling the controllable system components depending on the measured system state and user specifications.
15.Mobile Arbeitsmaschine mit wenigstens einem Hydrauliksystem nach einem der Ansprüche 1 bis 14.15.Mobile work machine with at least one hydraulic system according to one of claims 1 to 14.
lό.Mobile Arbeitsmaschine nach Anspruch 15, dadurch gekennzeichnet, dass mehrere Hochdruckkreise mit einem gemeinsamen Niederdruckkreis vorgesehen sind. Mobile machine according to claim 15, characterized in that several high pressure circuits are provided with a common low pressure circuit.
EP04701896A 2003-01-29 2004-01-14 Hydraulic system for linear drives controlled by a displacer element Expired - Lifetime EP1588057B1 (en)

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DE10303360 2003-01-29
DE10303360A DE10303360A1 (en) 2003-01-29 2003-01-29 Hydraulic system for displacement-controlled linear drives
PCT/DE2004/000032 WO2004067969A1 (en) 2003-01-29 2004-01-14 Hydraulic system for linear drives controlled by a displacer element

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010054149A2 (en) 2008-11-06 2010-05-14 Purdue Research Foundation Displacement-controlled hydraulic system for multi-function machines
WO2010054155A2 (en) 2008-11-06 2010-05-14 Purdue Research Foundation System and method for pump-controlled cylinder cushioning

Families Citing this family (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7325398B2 (en) * 2004-03-05 2008-02-05 Deere & Company Closed circuit energy recovery system for a work implement
US7516613B2 (en) 2004-12-01 2009-04-14 Haldex Hydraulics Corporation Hydraulic drive system
US7234298B2 (en) * 2005-10-06 2007-06-26 Caterpillar Inc Hybrid hydraulic system and work machine using same
US7191593B1 (en) 2005-11-28 2007-03-20 Northrop Grumman Corporation Electro-hydraulic actuator system
CN100424361C (en) * 2006-03-07 2008-10-08 太原理工大学 Closed electrohydraulic controlling system
US7467514B2 (en) * 2006-07-17 2008-12-23 Caterpillar Inc. System and method for controlling shakability of a work tool
US7707829B2 (en) * 2007-09-07 2010-05-04 Caterpillar S.A.R.L. Flushing system having a single charge relief valve
EP2055951B1 (en) * 2007-11-01 2019-03-27 Danfoss Power Solutions Aps Charged hydraulic system
US9410544B2 (en) 2007-11-01 2016-08-09 Danfoss Power Solutions Aps Charged hydraulic system
DE102008049181A1 (en) * 2008-09-26 2010-04-01 Schaeffler Kg Electrohydraulic valve control
US8474254B2 (en) 2008-11-06 2013-07-02 Purdue Research Foundation System and method for enabling floating of earthmoving implements
US7942208B2 (en) 2008-11-06 2011-05-17 Purdue Research Foundation System and method for blade level control of earthmoving machines
WO2011041410A2 (en) 2009-09-29 2011-04-07 Purdue Research Foundation Regenerative hydraulic systems and methods of use
WO2011075813A1 (en) 2009-12-23 2011-06-30 Husky Injection Molding Systems Ltd. Injection molding system having a digital displacement pump
DE102010040755A1 (en) * 2010-09-14 2012-03-15 Zf Friedrichshafen Ag drive arrangement
WO2012145401A1 (en) * 2011-04-18 2012-10-26 Concentric Rockford, Inc Engine augmentation of hydraulic control system
US8887499B2 (en) * 2011-06-29 2014-11-18 Caterpillar Inc. Electronic high hydraulic pressure cutoff to improve system efficiency
US9683585B2 (en) * 2011-08-24 2017-06-20 Komatsu Ltd. Hydraulic drive system
JP5752526B2 (en) * 2011-08-24 2015-07-22 株式会社小松製作所 Hydraulic drive system
US9057389B2 (en) * 2011-09-30 2015-06-16 Caterpillar Inc. Meterless hydraulic system having multi-actuator circuit
US20130081382A1 (en) * 2011-09-30 2013-04-04 Bryan E. Nelson Regeneration configuration for closed-loop hydraulic systems
US9096115B2 (en) 2011-11-17 2015-08-04 Caterpillar Inc. System and method for energy recovery
DE102012101231A1 (en) * 2012-02-16 2013-08-22 Linde Material Handling Gmbh Hydrostatic drive system
CN102588358B (en) * 2012-02-20 2015-01-21 北京理工大学 High-performance energy saving type electro-hydraulic servo control oil line
CN102606562A (en) * 2012-03-20 2012-07-25 王凡 Positioning control mechanism of vertical load for double-acting cylinder
JP6021144B2 (en) * 2012-07-17 2016-11-09 株式会社小松製作所 Hydraulic drive system
JP6053828B2 (en) * 2013-01-08 2016-12-27 日立建機株式会社 Hydraulic system of work machine
CN103307060B (en) * 2013-06-18 2016-02-03 南京埃斯顿自动化股份有限公司 The oil hydraulic cylinder control system of directly driving type servo-pump control electricity liquid combination drive and controlling method
KR20160130231A (en) * 2014-02-04 2016-11-10 다나 이탈리아 에스피에이 Travel and work functions integrated into a hydraulic hybrid system
CN103899316B (en) * 2014-03-21 2016-06-08 中铁工程装备集团有限公司 Shaft drilling method shaft drilling machine
GB2529909B (en) 2014-09-30 2016-11-23 Artemis Intelligent Power Ltd Industrial system with synthetically commutated variable displacement fluid working machine
US10927856B2 (en) * 2016-11-17 2021-02-23 University Of Manitoba Pump-controlled hydraulic circuits for operating a differential hydraulic actuator
CN112128153B (en) * 2020-09-03 2022-08-05 徐州重型机械有限公司 Novel variable-pressure-difference load sensing system of constant delivery pump and control method thereof

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2706091A1 (en) * 1977-02-12 1978-08-17 Orenstein & Koppel Ag DRIVE WITH A DIFFERENTIAL CYLINDER CONNECTED TO A CLOSED HYDRAULIC CIRCUIT
JPS57144344A (en) * 1981-03-02 1982-09-06 Hitachi Constr Mach Co Ltd Flushing valve
SE437861B (en) * 1983-02-03 1985-03-18 Goran Palmers DEVICE FOR MEDIUM HYDRAULIC CYLINDER OPERATED MACHINERY WITH ONE OF A DRIVE CELL THROUGH AN ENERGY CUMULATOR DRIVE PUMP
JPS6081502A (en) 1983-10-11 1985-05-09 Hitachi Constr Mach Co Ltd Driving device of closed circuit of hydraulic actuator
US5819574A (en) * 1996-06-07 1998-10-13 Kabushiki Kaisha Opton Hydraulic device for bending work and a bending device with the hydraulic device mounted thereon
DE19755120A1 (en) * 1997-02-27 1998-09-03 Mannesmann Rexroth Ag Pilot operated check valve
DE19716081C1 (en) 1997-04-17 1998-08-13 Hydac Technology Gmbh Hydraulic differential cylinder drive
WO2002004820A1 (en) 2000-07-10 2002-01-17 Kobelco Construction Machinery Co., Ltd. Hydraulic cylinder circuit

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2004067969A1 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010054149A2 (en) 2008-11-06 2010-05-14 Purdue Research Foundation Displacement-controlled hydraulic system for multi-function machines
WO2010054155A2 (en) 2008-11-06 2010-05-14 Purdue Research Foundation System and method for pump-controlled cylinder cushioning
EP2361334A2 (en) * 2008-11-06 2011-08-31 Purdue Research Foundation Displacement-controlled hydraulic system for multi-function machines
EP2361334A4 (en) * 2008-11-06 2014-03-05 Purdue Research Foundation Displacement-controlled hydraulic system for multi-function machines

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WO2004067969A1 (en) 2004-08-12
ES2285408T3 (en) 2007-11-16
ATE358777T1 (en) 2007-04-15
EP1588057B1 (en) 2007-04-04
US20060218913A1 (en) 2006-10-05
DE502004003395D1 (en) 2007-05-16
DE112004000521D2 (en) 2005-12-15

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