EP1943179A1 - Hydraulic unit - Google Patents

Hydraulic unit

Info

Publication number
EP1943179A1
EP1943179A1 EP06762989A EP06762989A EP1943179A1 EP 1943179 A1 EP1943179 A1 EP 1943179A1 EP 06762989 A EP06762989 A EP 06762989A EP 06762989 A EP06762989 A EP 06762989A EP 1943179 A1 EP1943179 A1 EP 1943179A1
Authority
EP
European Patent Office
Prior art keywords
hydraulic
hydraulic system
hydraulic pump
fluid
control device
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
EP06762989A
Other languages
German (de)
French (fr)
Other versions
EP1943179B1 (en
Inventor
Herbert Baltes
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.)
Hydac Technology GmbH
Original Assignee
Hydac Technology GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hydac Technology GmbH filed Critical Hydac Technology GmbH
Publication of EP1943179A1 publication Critical patent/EP1943179A1/en
Application granted granted Critical
Publication of EP1943179B1 publication Critical patent/EP1943179B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/22—Hydraulic devices or systems
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
    • 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
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/024—Installations or systems with accumulators used as a supplementary power source, e.g. to store energy in idle periods to balance pump load
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20561—Type of pump reversible
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/212—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being accumulators
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/625—Accumulators
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/88—Control measures for saving energy

Definitions

  • the invention relates to a hydraulic system, in particular for lifting and lowering of loads in forklifts with at least one working cylinder whose piston rod unit is movably guided in a housing and retractable by means of a hydraulic pump in its one drive direction and retractable in its other opposite drive direction and with a control device for controlling the traversing movements.
  • a suspension system is shown as a hydraulic system, in particular for use in a mast of a forklift, with at least one hydraulic accumulator and at least one switching valve for producing a fluid-carrying connection by means of a control line between the hydraulic accumulator and a mast operable by the mast , And with a lifting and lowering line for driving the working cylinder in a raised or lowered position, wherein the lifting and the sink line each open into a main branch, which open into parallel to each other with a connection point in front of and behind the switching valve in the control line and wherein in the main branches valves are connected, which have an opposite direction of action or drive for each main branch.
  • the prior art further discloses generic hydraulic systems in which two working cylinders connected to one another on the piston side are connected in the form of so-called plunger cylinders to a conventional hydraulic pump.
  • the hydraulic pump may have two opposite directions of rotation in the form of a fixed displacement pump and thus two opposite directions of transport for the fluid medium used.
  • a user-controllable control device in the manner of a control block allows the actuation of the hydraulic pump, to whose drive a conventional electric motor is used.
  • the hydraulic pump removes fluid from a tank supply container and pushes the removed fluid onto the piston side of said working cylinder unit.
  • the known hydraulic system To lower the load and thus to retract the working cylinder, the direction of rotation of the hydraulic pump is reversed, and the fluid displaced beyond the piston side again reaches the tank side of the known hydraulic system.
  • the known system For lifting and lowering of loads, the known system requires a high working capacity of the hydraulic pump and therefore a high drive power for the upstream electric motor. Also, the known hydraulic system, as regards the possible Verfahrgeschwindigi- th for the working cylinder, limited.
  • the present invention seeks to improve the known solutions to the effect that at low cost energetically favorable operation of a pertinent Hydraulic system is possible.
  • This object is achieved by a hydraulic system with the features of claim 1 in its entirety.
  • a memory device which undergoes a power supply in a drive direction of the hydraulic pump, and that the injected energy to support a movement in opposite direction of drive of the hydraulic pump from the storage device is retrievable, in particular, the lifting movement can be the storage device energy-assisted perform, which has a lower drive power for the hydraulic pump with its engine result.
  • the retrieved energy under high pressure level of the fluid from the storage device can also be used for faster traversing movements on the respective working cylinder, which in this respect benefits a rapid operation.
  • the use of the storage device overall a harmonious, smooth operation of the entire hydraulic system can be achieved. By simply reversing the rotation of the hydraulic pump, the amount of fluid displaced during the lowering of the load from the working cylinder can be inserted into the storage device to increase its pressure levels and retrieved from there again at the next working cycle.
  • a hydraulic accumulator for the accumulator device, in particular in the manner of a piston accumulator, and a valve unit serves as part of the operator-guided control device for producing or interrupting a fluid-conducting connection between the hydraulic pump and the accumulator device.
  • the hydraulic system is used in particular for lifting and lowering of loads not shown in forklifts, such as forklifts or other industrial trucks.
  • the plant has two working cylinders 10 of conventional design, which are also known in the trade as plunger cylinders, each working cylinder 10 has a piston-rod unit 12, the respective working cylinder 10 substantially fluid-tight in a KoI- benseite 14 and a rod side 16 divided.
  • the two piston sides 14 of the working cylinder 10 via a connecting line designated as a whole 18 in fluid communication with each other in connection and connected to an operator-controlled control device 20 in the manner of a control block.
  • the rod sides 16 are supplied in a conventional and therefore no longer shown manner with fluid in case of need, the pertinent amount of fluid is clearly removable again from the rod side 16 as an annular space.
  • the respective piston-rod unit 12 is guided in a housing 22 of the working cylinder 10 and for a lifting operation, not shown, a lifting load and / or for extending the mast of a forklift drives in the viewing direction, the piston rod unit 12 from the housing 22 upwards, and for a lowering operation, the piston-rod unit 12 moves in the direction of the piston side 14 of each working cylinder 10.
  • the pertinent lifting and lowering operations are known, so that will not be discussed in detail here at this point.
  • a commercially available hydraulic pump 26 is connected to the connecting line 18 between the control device 20 and a supply or storage tank 24 with two opposite directions of rotation, which are indicated by arrows 28 in the figure.
  • the hydraulic pump 26 fluid in two opposite directions 30, 32 transport, which are shown in the representation of the figure by the standard arrows of the standard drawing representation of the hydraulic pump 26.
  • the hydraulic pump 26 may be configured as a constant pump.
  • a valve unit 34 is connected in the manner of a 3/2-way or switching valve it, which is shown in the figure in an actuating position, in which a fluid-conducting connection between the hydraulic pump 26 and tank 24 is shown ,
  • a branch line 36 to a storage device 38 in the form of a hy- dro 1918 in the manner of a piston accumulator is shut off in this switching position.
  • a fluid-carrying connection between branch line 36 and Input side of the hydraulic pump 26 manufactured. In this case, the tank connection to the tank 24 is blocked.
  • the operator-controlled control device 20 is able to control both the hydride pump 26 and the valve unit 34 in a noticeable manner.
  • For operating the hydraulic pump 26 is a conventional, not shown electric motor, which is so far actuated by the control device 20.
  • a measuring point 40 can also be connected to monitor system states between the control device 20 and the hydraulic pump 26 in order to carry out, for example, pressure monitoring of the system. Depending on the sensors used, it is also possible to carry out further monitoring activities, also in combination with one another, based on temperature, viscosity, degree of contamination etc. of the fluid used in each case.
  • the valve unit 34 At a first start of the hydraulic system with flud nurse not filled memory 38, the valve unit 34 is in its switching position shown in the figure, and the hydraulic pump 26 takes fluid from the tank 24 and pushes the relevant amount in the direction of the piston side 14 of the working cylinder 10 for a lifting operation. Now, if the load is lowered, the valve 34 is actuated and the recirculated via the hydraulic pump 26 fluid now passes to the fluid side 42 of the storage device 38 and raises the piston against the working gas supply accordingly.
  • the separating element such as a piston or a membrane, separates the fluid side from the gas side enclosed in the storage housing, which can store energy in compressed fashion.
  • the energy stored in the storage device 38 is called up in the form of a high pressure level and supports the lifting movement, in that the rather retrieved fluid quantity is pushed to the piston side 14 of the respective working cylinder 10. In this way, a kind of energy storage can be reached, which can callably support the lifting process.
  • the hydraulic system according to the invention is characterized by the use of the storage device 38 in that short system and reaction times are possible at high extension and retraction speeds for the working cylinder 10 used, and the electric drive of the hydraulic pump 26 is relieved accordingly. Furthermore, it has been found that all working movements damped by the energy input into the memory device 38 are harmonious and therefore smooth. Despite the cost overhead for the realization of the indicated memory device, the associated energy saving is more cost-effective, especially in long-term operation than in systems without storage device. Also, the transport or capacity performance of the hydraulic pump 26 can be reduced by the use of the energy storage device 38, which in turn helps reduce the manufacturing cost.
  • the hydraulic pump used have two directions of rotation; However, the two directions of rotation can also be realized by means of the electric motor. It is also possible to replace the mentioned fixed-displacement pump with a variable displacement pump and the electric motor can also be replaced by another drive device, for example by an internal combustion engine, preferably in the form of a diesel engine, a working machine or the like.
  • the hydraulic system according to the invention is not limited to use in forklifts, but can preferably always be used where position energy is to be applied with the respective working cylinder. A more obvious Use is accordingly possible in working machines, such as excavators, but also in the area of elevators and handling equipment (manipulators).
  • the directional control valve used in the circuit of the figure is formed in the manner of a 3/2-way valve; Here is also an implementation with a 3/3-way valve conceivable that can contribute to the extent corresponding to the switching position to relieve the memory 38 with. Furthermore, the control device 20 shown in the figure need not be realized in this way and can accordingly be dispensed with. Necessarily, then, only a control device for driving the motor and / or the indicated hydraulic pump. Instead of the control device 20 shown in the figure, a pipe rupture protection or the like could be inserted into the hydraulic system at this point (not shown). In the control of the overall system, a corresponding sensor with measuring points for the hydraulic accumulator can be used. Thus, for example, by monitoring the piston position of the hydraulic accumulator as well as the degree of its filling volume and / or filling pressure, further statements could be made for controlling the overall hydraulic system.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Civil Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Forklifts And Lifting Vehicles (AREA)

Abstract

Hydraulic system has a storage device (38), which experiences an energy feed in the drive direction (32). The fed energy can be recalled from the support of a displacement movement during drive direction (30) moving in opposite directions from the storage device.

Description

Hydac Technology GmbH, Industriegebiet, 66280 Sulzbach/Saar Hydac Technology GmbH, industrial area, 66280 Sulzbach / Saar
Hydraulikanlagehydraulic system
Die Erfindung betrifft eine Hydraulikanlage, insbesondere zum Heben und Senken von Lasten bei Staplern mit mindestens einem Arbeitszylinder, dessen Kolben-Stangen-Einheit in einem Gehäuse bewegbar geführt und mittels einer Hydropumpe in seiner einen Antriebsrichtung ausfahrbar und in sei- ner anderen gegenläufigen Antriebsrichtung einfahrbar ist und mit einer Steuereinrichtung zum Ansteuern der dahingehenden Verfahrbewegungen.The invention relates to a hydraulic system, in particular for lifting and lowering of loads in forklifts with at least one working cylinder whose piston rod unit is movably guided in a housing and retractable by means of a hydraulic pump in its one drive direction and retractable in its other opposite drive direction and with a control device for controlling the traversing movements.
Durch die nachveröffentlichte DE 10 2004 044 244 ist als Hydraulikanlage ein Federungssystem aufgezeigt, insbesondere für den Einsatz bei einem Hubgerüst eines Gabelstaplers, mit mindestens einem Hydrospeicher sowie mindestens einem Schaltventil zum Herstellen einer fluidführenden Verbindung mittels einer Steuerleitung zwischen dem Hydrospeicher und einem das Hubgerüst betätigbaren Arbeitszylinder, und mit einer Heben- und Senkenleitung zum Ansteuern des Arbeitszylinders in eine angehobene bzw. abgesenkte Stellung, wobei die Heben- und die Senkenleitung jeweils in einen Hauptzweig münden, die parallel zueinander verlaufend jeweils mit einer Anschlussstelle vor und hinter dem Schaltventil in die Steuerleitung münden und wobei in die Hauptzweige Ventile geschaltet sind, die für jeden Hauptzweig eine entgegengesetzte Wirk- oder Ansteuerrichtung haben. Mit der aufgezeigten Lösung ist eine Art hydraulische Graetz-Schaltung realisiert und mit der aufgezeigten Lösung ist es möglich, mit nur wenigen Ein- baukomponenten und insbesondere auch nur unter Einsatz eines Hydro speichers eine wirksame Lastdämpfung oder Federung bei einem Hubgerüst eines Gabelstaplers zu erreichen. Ein energetisch sparsamer Betrieb ist jedoch mit der bekannten Lösung nicht möglich.By subsequently published DE 10 2004 044 244 a suspension system is shown as a hydraulic system, in particular for use in a mast of a forklift, with at least one hydraulic accumulator and at least one switching valve for producing a fluid-carrying connection by means of a control line between the hydraulic accumulator and a mast operable by the mast , And with a lifting and lowering line for driving the working cylinder in a raised or lowered position, wherein the lifting and the sink line each open into a main branch, which open into parallel to each other with a connection point in front of and behind the switching valve in the control line and wherein in the main branches valves are connected, which have an opposite direction of action or drive for each main branch. With the solution shown a kind of hydraulic Graetz circuit is realized and with the indicated solution it is possible, with only a few inputs. construction components and in particular only with the use of a hydraulic storage to achieve effective load damping or suspension in a mast of a forklift. An energetically economical operation is not possible with the known solution.
Durch den Stand der Technik sind ferner gattungsgemäße Hydraulikanlagen bekannt, bei denen zwei auf der Kolbenseite miteinander verbundene Arbeitszylinder in Form so genannter Plunger-Zylinder an eine konventionelle Hydropumpe angeschlossen sind. Die Hydropumpe kann in der Art einer Konstantpumpe ausgebildet zwei gegenläufige Drehrichtungen aufweisen und mithin zwei gegenläufige Transportrichtungen für das eingesetzte Fluidmedium. Eine bedienerseitig ansteuerbare Steuereinrichtung in der Art eines Steuerblockes erlaubt das Betätigen der Hydropumpe, zu deren Antrieb ein üblicher Elektromotor eingesetzt ist. Zum Ausfahren der Arbeitszy- linder und mithin zum Heben einer Last entnimmt bei der bekannten Lösung die Hydropumpe Fluid aus einem Tankvorratsbehälter und schiebt das entnommene Fluid auf die Kolbenseite der genannten Arbeitszylindereinheit. Zum Senken der Last und mithin zum Einfahren der Arbeitszylinder wird die Drehrichtung der Hydropumpe umgekehrt, und das über die KoI- benseite verdrängte Fluid gelangt wiederum auf die Tankseite der bekannten Hydraulikanlage. Zum Heben und Senken von Lasten benötigt die bekannte Anlage ein hohes Arbeitsvermögen der Hydropumpe und mithin eine hohe Antriebsleistung für den vorgeschalteten Elektromotor. Auch ist die bekannte Hydraulikanlage, was die möglichen Verfahrgeschwindigkei- ten für die Arbeitszylinder anbelangt, eingeschränkt.The prior art further discloses generic hydraulic systems in which two working cylinders connected to one another on the piston side are connected in the form of so-called plunger cylinders to a conventional hydraulic pump. The hydraulic pump may have two opposite directions of rotation in the form of a fixed displacement pump and thus two opposite directions of transport for the fluid medium used. A user-controllable control device in the manner of a control block allows the actuation of the hydraulic pump, to whose drive a conventional electric motor is used. In order to extend the working cylinder and thus to lift a load, in the known solution the hydraulic pump removes fluid from a tank supply container and pushes the removed fluid onto the piston side of said working cylinder unit. To lower the load and thus to retract the working cylinder, the direction of rotation of the hydraulic pump is reversed, and the fluid displaced beyond the piston side again reaches the tank side of the known hydraulic system. For lifting and lowering of loads, the known system requires a high working capacity of the hydraulic pump and therefore a high drive power for the upstream electric motor. Also, the known hydraulic system, as regards the possible Verfahrgeschwindigi- th for the working cylinder, limited.
Ausgehend von diesem Stand der Technik liegt der Erfindung die Aufgabe zugrunde, die bekannten Lösungen dahingehend weiter zu verbessern, dass bei geringen Kosten ein energetisch günstiger Betrieb einer dahingehenden Hydraulikanlage möglich ist. Eine dahingehende Aufgabe löst eine Hydraulikanlage mit den Merkmalen des Patentanspruchs 1 in seiner Gesamtheit.Based on this prior art, the present invention seeks to improve the known solutions to the effect that at low cost energetically favorable operation of a pertinent Hydraulic system is possible. This object is achieved by a hydraulic system with the features of claim 1 in its entirety.
Dadurch dass gemäß dem kennzeichnenden Teil des Patentanspruches 1 eine Speichereinrichtung vorhanden ist, die in einer Antriebsrichtung der Hydropumpe eine Energieeinspeisung erfährt, und dass die eingespeiste Energie zur Unterstützung einer Verfahrbewegung bei gegenläufiger Antriebsrichtung der Hydropumpe aus der Speichereinrichtung abrufbar ist, lässt sich insbesondere die Lasthebebewegung aus der Speichereinrichtung energieunterstützt durchführen, was eine geringere Antriebsleistung für die Hydropumpe mit ihrem Motor zur Folge hat. Die abgerufene Energie unter hohem Druckniveau des Fluids aus der Speichereinrichtung kann auch zu schnelleren Verfahrbewegungen am jeweiligen Arbeitszylinder eingesetzt werden, was insoweit einem raschen Betriebsablauf zugute kommt. Ferner hat es sich gezeigt, dass durch den Einsatz der Speichereinrichtung insgesamt ein harmonischer, ruckfreier Betrieb der Gesamthydraulikanlage erreichbar ist. Durch einfache Drehumkehr der Hydropumpe lässt sich die beim Absenken der Last aus dem Arbeitszylinder verdrängte Fluidmenge in die Speichereinrichtung zur Erhöhung deren Druckniveaus einschieben und beim nächsten Arbeitszyklus von dort wieder abrufen.Characterized that according to the characterizing part of claim 1, a memory device is present, which undergoes a power supply in a drive direction of the hydraulic pump, and that the injected energy to support a movement in opposite direction of drive of the hydraulic pump from the storage device is retrievable, in particular, the lifting movement can be the storage device energy-assisted perform, which has a lower drive power for the hydraulic pump with its engine result. The retrieved energy under high pressure level of the fluid from the storage device can also be used for faster traversing movements on the respective working cylinder, which in this respect benefits a rapid operation. Furthermore, it has been found that the use of the storage device overall a harmonious, smooth operation of the entire hydraulic system can be achieved. By simply reversing the rotation of the hydraulic pump, the amount of fluid displaced during the lowering of the load from the working cylinder can be inserted into the storage device to increase its pressure levels and retrieved from there again at the next working cycle.
Als besonders vorteilhaft hat es sich dabei erwiesen, für die Speichereinrichtung einen Hydrospeicher insbesondere in der Art eines Kolbenspeichers einzusetzen und als Teil der bedienerseitig geführten Steuereinrichtung dient eine Ventileinheit zum Herstellen oder Unterbrechen einer fluidfüh- renden Verbindung zwischen der Hydropumpe und der Speichereinrichtung. Trotz der zu erwartenden Mehrkosten für den Aufwand einer zusätzlichen Speichereinrichtung, vorzugsweise in Form eines Hydrospeichers^ sind die zu erwartenden Einsparungen durch den energetisch günstigen Fahrbetrieb höher anzusetzen, sodass bereits bei kurzer Einsatzdauer der Energiespei- cherung die dahingehenden Mehrkosten ausgeglichen sind. Insgesamt lassen sich also durch Einsatz der Speichereinrichtung die Betriebskosten bei dahingehenden Hydraulikanlagen senken.It has proved to be particularly advantageous to use a hydraulic accumulator for the accumulator device, in particular in the manner of a piston accumulator, and a valve unit serves as part of the operator-guided control device for producing or interrupting a fluid-conducting connection between the hydraulic pump and the accumulator device. Despite the expected additional costs for the expense of an additional storage device, preferably in the form of a hydraulic accumulator ^ the expected savings due to the energetically favorable driving operation are set higher, so that even with a short period of use of energy storage the pertinent additional costs are compensated. Overall, by using the storage device, the operating costs can be reduced in the case of corresponding hydraulic systems.
Im Folgenden wird die erfindungsgemäße Hydraulikanlage anhand eines Ausführungsbeispieles nach der Zeichnung näher erläutert. Dabei zeigt die einzige Figur in prinzipieller und nicht maßstäblicher Darstellung in der Art eines Blockschaltbildes die erfindungsgemäße Hydraulikanlage.In the following, the hydraulic system according to the invention is explained in more detail using an exemplary embodiment according to the drawing. The single figure in a schematic and not to scale representation in the form of a block diagram shows the hydraulic system according to the invention.
Die Hydraulikanlage dient insbesondere dem Heben und Senken von nicht näher dargestellten Lasten bei Staplern, wie Gabelstaplern oder sonstigen Flurförderfahrzeugen. Die Anlage weist zwei Arbeitszylinder 10 auf üblicher Bauart, die man in der Fachsprache auch mit Plunger-Zylinder bezeichnet, jeder Arbeitszylinder 10 weist eine Kolben-Stangen-Einheit 12 auf, die den jeweiligen Arbeitszylinder 10 im Wesentlich fluiddicht in eine KoI- benseite 14 und eine Stangenseite 16 unterteilt. Wie des Weiteren die Figur zeigt, sind die beiden Kolbenseiten 14 der Arbeitszylinder 10 über eine als Ganzes mit 18 bezeichnete Verbindungsleitung fluidführend miteinander in Verbindung und dergestalt an eine bedienergeführte Steuereinrichtung 20 in der Art eines Steuerblockes angeschlossen. Die Stangenseiten 16 werden in üblicher und daher nicht mehr näher dargestellter Weise mit Fluid im Bedarfsfall versorgt, wobei die dahingehende Fluidmenge sinnfällig auch wieder aus der Stangenseite 16 als Ringraum abtransportierbar ist. Die jeweilige Kolben-Stangen-Einheit 12 ist in einem Gehäuse 22 des Arbeitszylinders 10 geführt und für einen nicht näher dargestellten Anhebevorgang einer Hublast und/oder zum Ausfahren des Hubgerüstes eines Gabelstaplers fährt in Blickrichtung gesehen die Kolbenstangeneinheit 12 aus dem Gehäuse 22 nach oben aus, und für einen Absenkvorgang bewegt sich die Kolben-Stangen-Einheit 12 in Richtung auf die Kolbenseite 14 eines jeden Arbeitszylinders 10. Die dahingehenden Hebe- und Absenkvorgänge sind bekannt, sodass an dieser Stelle hierauf nicht mehr detailliert eingegangen wird.The hydraulic system is used in particular for lifting and lowering of loads not shown in forklifts, such as forklifts or other industrial trucks. The plant has two working cylinders 10 of conventional design, which are also known in the trade as plunger cylinders, each working cylinder 10 has a piston-rod unit 12, the respective working cylinder 10 substantially fluid-tight in a KoI- benseite 14 and a rod side 16 divided. As further shown in the figure, the two piston sides 14 of the working cylinder 10 via a connecting line designated as a whole 18 in fluid communication with each other in connection and connected to an operator-controlled control device 20 in the manner of a control block. The rod sides 16 are supplied in a conventional and therefore no longer shown manner with fluid in case of need, the pertinent amount of fluid is clearly removable again from the rod side 16 as an annular space. The respective piston-rod unit 12 is guided in a housing 22 of the working cylinder 10 and for a lifting operation, not shown, a lifting load and / or for extending the mast of a forklift drives in the viewing direction, the piston rod unit 12 from the housing 22 upwards, and for a lowering operation, the piston-rod unit 12 moves in the direction of the piston side 14 of each working cylinder 10. The pertinent lifting and lowering operations are known, so that will not be discussed in detail here at this point.
In die Verbindungsleitung 18 ist des Weiteren zwischen Steuereinrichtung 20 und einem Versorgungs- oder Vorratstank 24 eine marktübliche Hydro- pumpe 26 geschaltet mit zwei gegenläufigen Drehrichtungen, die in der Figur mit Pfeilen 28 angedeutet sind. Im Hinblick auf die gegenläufigen Drehrichtungen 28 kann die Hydropumpe 26 Fluid in zwei gegenläufige Richtungen 30, 32 transportieren, die gemäß der Darstellung nach der Figur durch die Normpfeile der genormten Zeichnungsdarstellung der Hydropumpe 26 wiedergegeben sind. Die Hydropumpe 26 kann als Konstantpumpe ausgestaltet sein.Furthermore, a commercially available hydraulic pump 26 is connected to the connecting line 18 between the control device 20 and a supply or storage tank 24 with two opposite directions of rotation, which are indicated by arrows 28 in the figure. With regard to the opposite directions of rotation 28, the hydraulic pump 26 fluid in two opposite directions 30, 32 transport, which are shown in the representation of the figure by the standard arrows of the standard drawing representation of the hydraulic pump 26. The hydraulic pump 26 may be configured as a constant pump.
Zwischen Hydropumpe 26 und Tank 24 ist eine Ventileinheit 34 geschaltet in der Art eines 3/2-Wege- oder Schaltventil es, das gemäß der Darstellung nach der Figur in einer Betätigungsstellung wiedergegeben ist, bei der eine fluidführende Verbindung zwischen Hydropumpe 26 und Tank 24 besteht. Eine Abzweigleitung 36 zu einer Speichereinrichtung 38 in Form eines Hy- drospeichers in der Art eines Kolbenspeichers ist in dieser Schaltstellung abgesperrt. In der anderen Schaltsperrung des Wegeventiles wird hingegen dergestalt eine fluidführende Verbindung zwischen Abzweigleitung 36 und Eingangsseite der Hydropumpe 26 hergestellt. Im dahingehenden Fall ist der Tankanschluss zum Tank 24 gesperrt.Between the hydraulic pump 26 and the tank 24, a valve unit 34 is connected in the manner of a 3/2-way or switching valve it, which is shown in the figure in an actuating position, in which a fluid-conducting connection between the hydraulic pump 26 and tank 24 is shown , A branch line 36 to a storage device 38 in the form of a hy- drospeicher in the manner of a piston accumulator is shut off in this switching position. In contrast, in the other switching blocking the directional control valve, a fluid-carrying connection between branch line 36 and Input side of the hydraulic pump 26 manufactured. In this case, the tank connection to the tank 24 is blocked.
Die bedienergeführte Steuereinrichtung 20 ist in der Lage, sowohl die Hy- dropumpe 26 als auch die Ventileinheit 34 sinnfällig anzusteuern. Zum Betrieb der Hydropumpe 26 dient ein üblicher, nicht näher dargestellter Elektromotor, der insoweit von der Steuereinrichtung 20 betätigbar ist. Ferner kann noch zur Überwachung von Systemzuständen zwischen der Steuereinrichtung 20 und der Hydropumpe 26 eine Messstelle 40 geschaltet sein, um dergestalt beispielsweise eine Drucküberwachung des Systems durchzuführen. In Abhängigkeit der eingesetzten Sensorik lassen sich auch weitergehende Überwachungstätigkeiten durchführen, auch in Kombination miteinander, bezogen auf Temperatur, Viskosität, Verschmutzungsgrad etc. des jeweils eingesetzten Fluids.The operator-controlled control device 20 is able to control both the hydride pump 26 and the valve unit 34 in a noticeable manner. For operating the hydraulic pump 26 is a conventional, not shown electric motor, which is so far actuated by the control device 20. Furthermore, a measuring point 40 can also be connected to monitor system states between the control device 20 and the hydraulic pump 26 in order to carry out, for example, pressure monitoring of the system. Depending on the sensors used, it is also possible to carry out further monitoring activities, also in combination with one another, based on temperature, viscosity, degree of contamination etc. of the fluid used in each case.
Bei einem Erstanlauf der Hydraulikanlage bei fludseitig nicht befülltem Speicher 38 ist die Ventileinheit 34 in ihrer in der Figur gezeigten Schaltstellung, und die Hydropumpe 26 entnimmt Fluid aus dem Tank 24 und schiebt die diesbezügliche Menge in Richtung der Kolbenseite 14 der Ar- beitszylinder 10 für einen Hebevorgang. Wird nun die Last abgesenkt, wird das Ventil 34 betätigt und die über die Hydropumpe 26 rückgeführte Fluidmenge gelangt nun auf die Fluidseite 42 der Speichereinrichtung 38 und hebt den Kolben gegen den Arbeitsgasvorrat entsprechend an. Bekanntermaßen trennt bei einem Hydrospeicher das Trennelement wie ein KoI- ben oder eine Membran die Fluidseite von der im Speichergehäuse eingeschlossenen Gasseite, die komprimiert dergestalt Energie speichern kann. Wird nun ein erneuter Lasthebevorgang ausgelöst, wird die in der Speichereinrichtung 38 eingespeicherte Energie in Form eines hohen Druckniveaus abgerufen und unterstützt die Hebebewegung, indem die vom Spei- eher abgerufene Fluidmenge zur Kolbenseite 14 des jeweiligen Arbeitszylinders 10 geschoben wird. Dergestalt ist eine Art Energiespeicherung erreichbar, die abrufbar den Lasthebevorgang unterstützen kann.At a first start of the hydraulic system with fludseitig not filled memory 38, the valve unit 34 is in its switching position shown in the figure, and the hydraulic pump 26 takes fluid from the tank 24 and pushes the relevant amount in the direction of the piston side 14 of the working cylinder 10 for a lifting operation. Now, if the load is lowered, the valve 34 is actuated and the recirculated via the hydraulic pump 26 fluid now passes to the fluid side 42 of the storage device 38 and raises the piston against the working gas supply accordingly. As is known, in the case of a hydraulic accumulator, the separating element, such as a piston or a membrane, separates the fluid side from the gas side enclosed in the storage housing, which can store energy in compressed fashion. If a new load lifting process is now triggered, the energy stored in the storage device 38 is called up in the form of a high pressure level and supports the lifting movement, in that the rather retrieved fluid quantity is pushed to the piston side 14 of the respective working cylinder 10. In this way, a kind of energy storage can be reached, which can callably support the lifting process.
Die erfindungsgemäße Hydraulikanlage zeichnet sich durch Einsatz der Speichereinrichtung 38 dadurch aus, dass kurze System- und Reaktionszeiten möglich sind bei hohen Aus- und Einfahrgeschwindigkeiten für die eingesetzten Arbeitszylinder 10, und der Elektroantrieb der Hydropumpe 26 ist entsprechend entlastet. Ferner hat es sich gezeigt, dass alle Arbeitsbewe- gungen gedämpft durch den Energieeintrag in die Speichereinrichtung 38 harmonisch und mithin ruckfrei erfolgen. Trotz des Kostenmehraufwandes für die Realisierung der aufgezeigten Speichereinrichtung ist insbesondere im langfristigen Betrieb die damit einhergehende Energieeinsparung kosteneffizienter als bei Anlagen ohne Speichereinrichtung. Auch kann die Transport- oder Kapazitätsleistung der Hydropumpe 26 durch den Einsatz der Energiespeichereinrichtung 38 zurückgefahren werden, was wiederum die Herstell kosten senken hilft.The hydraulic system according to the invention is characterized by the use of the storage device 38 in that short system and reaction times are possible at high extension and retraction speeds for the working cylinder 10 used, and the electric drive of the hydraulic pump 26 is relieved accordingly. Furthermore, it has been found that all working movements damped by the energy input into the memory device 38 are harmonious and therefore smooth. Despite the cost overhead for the realization of the indicated memory device, the associated energy saving is more cost-effective, especially in long-term operation than in systems without storage device. Also, the transport or capacity performance of the hydraulic pump 26 can be reduced by the use of the energy storage device 38, which in turn helps reduce the manufacturing cost.
Die eingesetzte Hydropumpe kann, wie dargelegt, zwei Drehrichtungen aufweisen; die beiden Drehrichtungen können aber auch mittels des Elektromotors realisiert sein. Auch ist es möglich, die angesprochene Konstantpumpe durch eine Verstellpumpe sinnfällig zu ersetzen und der Elektromotor kann auch durch eine andere Antriebsvorrichtung ersetzt sein, beispielsweise durch einen Verbrennungsmotor, vorzugsweise in Form eines Dieselmotors, einer Arbeitsmaschine oder dergleichen. Die erfindungsgemäße Hydraulikanlage ist nicht auf den Einsatz bei Staplern beschränkt, sondern kann vorzugsweise immer dort eingesetzt werden, wo mit dem jeweiligen Arbeitszylinder Lageenergie aufzubringen ist. Ein sinnfälliger Einsatz ist demgemäß bei Arbeitsmaschinen möglich, wie Baggern, aber auch im Bereich von Aufzügen und Handhabungsgeräten (Manipulatoren).The hydraulic pump used, as set forth, have two directions of rotation; However, the two directions of rotation can also be realized by means of the electric motor. It is also possible to replace the mentioned fixed-displacement pump with a variable displacement pump and the electric motor can also be replaced by another drive device, for example by an internal combustion engine, preferably in the form of a diesel engine, a working machine or the like. The hydraulic system according to the invention is not limited to use in forklifts, but can preferably always be used where position energy is to be applied with the respective working cylinder. A more obvious Use is accordingly possible in working machines, such as excavators, but also in the area of elevators and handling equipment (manipulators).
Das in der Schaltung nach der Figur eingesetzte Wegeventil ist in der Art eines 3/2-Wege-Ventils ausgebildet; hier ist auch eine Realisierung mit einem 3/3-Wege-Ventil denkbar, das insoweit entsprechend der Schaltstellung zum Entlasten des Speichers 38 mit beitragen kann. Ferner braucht die in der Figur dargestellte Steuereinrichtung 20 dergestalt nicht realisiert zu sein und kann demgemäß entfallen. Notwendig ist dem Grunde nach dann nur eine Steuereinrichtung zum Ansteuern des Motors und/oder der aufgezeigten Hydropumpe. Anstelle der in der Figur gezeigten Steuereinrichtung 20 könnte an dieser Stelle auch eine Rohrbruchsicherung oder dergleichen in die Hydraulikanlage eingesetzt sein (nicht dargestellt). In die Ansteuerung des Gesamtsystems kann auch eine entsprechende Sensorik mit Meßstellen für den Hydrospeicher eingesetzt sein. So ließen sich beispielsweise durch die Überwachung der Kolbenposition des Hydrospeichers sowie über den Grad seines Füllvolumens und/oder Fülldruckes weitere Aussagen für die Ansteuerung der Gesamthydraulikanlage treffen. The directional control valve used in the circuit of the figure is formed in the manner of a 3/2-way valve; Here is also an implementation with a 3/3-way valve conceivable that can contribute to the extent corresponding to the switching position to relieve the memory 38 with. Furthermore, the control device 20 shown in the figure need not be realized in this way and can accordingly be dispensed with. Necessarily, then, only a control device for driving the motor and / or the indicated hydraulic pump. Instead of the control device 20 shown in the figure, a pipe rupture protection or the like could be inserted into the hydraulic system at this point (not shown). In the control of the overall system, a corresponding sensor with measuring points for the hydraulic accumulator can be used. Thus, for example, by monitoring the piston position of the hydraulic accumulator as well as the degree of its filling volume and / or filling pressure, further statements could be made for controlling the overall hydraulic system.

Claims

P a t e n t a n s p r ü c h e Patent claims
1. Hydraulikanlage, insbesondere zum Heben und Senken von Lasten bei Staplern mit mindestens einem Arbeitszylinder (10), dessen Kolben- Stangen-Einheit (12) in einem Gehäuse (22) bewegbar geführt und mittels einer Hydropumpe (26) in seiner einen Antriebsrichtung (30) aus- fahrbar und in seiner anderen gegenläufigen Antriebsrichtung (32) einfahrbar ist und mit einer Steuereinrichtung (20) zum Ansteuern der dahingehenden Verfahrbewegungen, dadurch gekennzeichnet, dass eine Speichereinrichtung (38) vorhanden ist, die in einer Antriebsrichtung (32) eine Energieeinspeisung erfährt, und dass die eingespeiste Energie zur Unterstützung einer Verfahrbewegung bei gegenläufiger Antriebsrichtung (30) aus der Speichereinrichtung (38) abrufbar ist.1. Hydraulic system, in particular for lifting and lowering loads in forklifts with at least one working cylinder (10) whose piston rod unit (12) in a housing (22) movably guided and by means of a hydraulic pump (26) in its one drive direction ( 30) extendable and in its other opposite drive direction (32) is retractable and with a control device (20) for controlling the traversing movements, characterized in that a memory device (38) is provided, in a drive direction (32) a power supply learns, and that the injected energy to support a movement in opposite direction drive (30) from the memory device (38) is retrievable.
2. Hydraulikanlage nach Anspruch 1, dadurch gekennzeichnet, dass beim Absenken der Kolben-Stangen-Einheit (12) die Energieeinspeisung er- folgt und beim Anheben die eingespeiste Energie zur Unterstützung dient.2. Hydraulic system according to claim 1, characterized in that when lowering the piston-rod unit (12), the energy is fed in and used when lifting the injected energy to support.
3. Hydraulikanlage nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Speichereinrichtung (38) aus mindestens einem Hydrospeicher, insbesondere einem Kolbenspeicher gebildet ist, der mittels einer über die Steuereinrichtung (20) betätigbaren Ventileinheit (34) zu- oder abschaltbar ist.3. Hydraulic system according to claim 1 or 2, characterized in that the storage device (38) from at least one hydraulic accumulator, in particular a piston accumulator is formed, which can be switched on or off by means of a via the control device (20) operable valve unit (34).
4. Hydraulikanlage nach Anspruch 3, dadurch gekennzeichnet, dass die Ventileinheit (34) ein Wegeventil ist, das in einer Schaltstellung den fluidführenden Weg freigibt zwischen einem Tankanschluss T und der Hydropumpe (26) und in der anderen Schaltstellung eine fluidführende Verbindung zwischen Hydropumpe (26) und Speichereinrichtung (38) herstellt.4. Hydraulic system according to claim 3, characterized in that the valve unit (34) is a directional control valve which releases the fluid-carrying path in a switching position between a tank port T and the hydraulic pump (26) and in the other switching position a fluid-carrying Connection between the hydraulic pump (26) and memory device (38) manufactures.
5. Hydraulikanlage nach einem der Ansprüche 1 bis 4, dadurch gekenn- zeichnet, dass die Steuereinrichtung (20) in eine fluidführende Verbindung zwischen dem jeweiligen Arbeitszyiinder (10) und der Ausgangsseite der Hydropumpe (26) geschaltet ist.5. Hydraulic system according to one of claims 1 to 4, characterized in that the control device (20) in a fluid-conducting connection between the respective Arbeitszyiinder (10) and the output side of the hydraulic pump (26) is connected.
6. Hydraulikanlage nach Anspruch 5, dadurch gekennzeichnet, dass eine Messstelle (40), insbesondere Druckmessstelle in die Verbindungsleitung (18) zwischen der Steuereinrichtung (20) und der Ausgangsseite der Hydropumpe (26) geschaltet ist.6. Hydraulic system according to claim 5, characterized in that a measuring point (40), in particular pressure measuring point in the connecting line (18) between the control device (20) and the output side of the hydraulic pump (26) is connected.
7. Hydraulikanlage nach einem der Ansprüche 1 bis 6, dadurch gekenn- zeichnet, dass eine Doppel-Arbeitszylinderanordnung (10) eingesetzt ist, die kolbenseitig (14) an die Ausgangsseite der Steuereinrichtung (20) fluidführend angeschlossen ist. 7. Hydraulic system according to one of claims 1 to 6, characterized in that a double-working cylinder arrangement (10) is used, the piston side (14) to the output side of the control device (20) is connected fluid leading.
EP06762989A 2005-11-02 2006-08-05 Hydraulic unit Not-in-force EP1943179B1 (en)

Applications Claiming Priority (2)

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DE102005052108A DE102005052108A1 (en) 2005-11-02 2005-11-02 Hydraulic system for lifting and lowering loads with stacks, has fed energy which can be recalled from support of displacement movement during drive direction moving in opposite directions from storage device
PCT/EP2006/007768 WO2007051502A1 (en) 2005-11-02 2006-08-05 Hydraulic unit

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US7891181B2 (en) 2011-02-22
JP2009515100A (en) 2009-04-09
EP1943179B1 (en) 2012-03-21
WO2007051502A1 (en) 2007-05-10
ATE550290T1 (en) 2012-04-15
DE102005052108A1 (en) 2007-05-03
US20090120084A1 (en) 2009-05-14

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