EP1293669B1 - Hydraulic vehicle steering pump driven by combustion engine - Google Patents
Hydraulic vehicle steering pump driven by combustion engine Download PDFInfo
- Publication number
- EP1293669B1 EP1293669B1 EP20020019785 EP02019785A EP1293669B1 EP 1293669 B1 EP1293669 B1 EP 1293669B1 EP 20020019785 EP20020019785 EP 20020019785 EP 02019785 A EP02019785 A EP 02019785A EP 1293669 B1 EP1293669 B1 EP 1293669B1
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- European Patent Office
- Prior art keywords
- steering
- pressure
- pump
- steering pump
- working machine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 238000002485 combustion reaction Methods 0.000 title claims description 15
- 238000006073 displacement reaction Methods 0.000 claims description 7
- 238000011144 upstream manufacturing Methods 0.000 claims description 3
- 230000001960 triggered effect Effects 0.000 claims description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000005381 potential energy Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
- F04B17/05—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by internal-combustion engines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B23/00—Pumping installations or systems
- F04B23/02—Pumping installations or systems having reservoirs
Definitions
- the invention relates to a mobile working machine, in particular industrial truck, with an internal combustion engine and a hydraulic steering pump driven therefrom for supplying a steering actuator.
- the supply of the steering system of internal combustion engine-powered forklifts with hydraulic energy is performed by a steering pump whose delivery volume is measured at the lower idle speed of the internal combustion engine. At this speed, the steering pump already promotes sufficient pressure fluid to supply the steering actuator so far that a minimum steering speed is achieved. Due to the principle, this leads to large-volume steering pumps, which have a high torque requirement. With increasing operating speed of the engine considerable energy losses occur because more pressure medium is conveyed by the steering pump than the steering actuator needed. In forklifts, in which the hydraulic pump supplies not only the steering cylinder but also a working hydraulics (priority valve switching), the entire pressure medium, including the quantity required for the working hydraulics, is always pressurized. This too leads to energy losses and to heating of the entire hydraulic system.
- the present invention is based on the object to provide a mobile machine of the type mentioned above, in which the energy losses caused by the steering system are minimized.
- a hydraulic accumulator is connected to the steering pump and the steering actuator and that the specific delivery volume of the steering pump is so dimensioned that the operation of the steering actuator at low operating speeds of the internal combustion engine, the injection of pressure medium from the steering pump and the memory requires and when a threshold speed is exceeded, the operation of the steering cylinder by solely feeding pressure medium from the steering pump is possible.
- the idea essential to the invention is therefore to significantly reduce the specific delivery volume of the steering pump, so the delivery volume per revolution and compensate to provide a sufficiently large memory that is loaded by the steering pump and from the operating conditions in certain, namely at low operating speeds of Internal combustion engine, in addition to the steering pump pressure medium is fed into the steering actuator.
- the delivery volume of the steering pump can be halved or even divided into three. This reduces the energy losses and the torque requirement of the steering pump to the same extent.
- the steering pump is smaller and requires less space in the machine.
- the torque demand on the internal combustion engine is reduced especially in the range of low operating speeds, which allows the use of small-sized turbo engines, which are rather weak in torque especially in this operating range. Overall, the energy losses in the steering circuit are significantly reduced.
- the volume of the memory is so dimensioned that with sole supply of the steering actuator by pressure medium from the full memory multiple actuation of the steering actuator from stop to stop is possible.
- a Notenergypump the steering actuator is ensured in case of failure of the engine or the steering pump. It requires no additional effort of the driver of the machine to use the emergency power supply.
- a pressure sensor in the memory directly or indirectly detected pressure sensor is provided, which is in operative connection with a brake system of the machine, which falls below a pressure limit, a positively controlled braking operation can be triggered. With pressure loss in the steering circuit, the working machine is thus brought into a safe state.
- the threshold speed of the internal combustion engine is advantageously in the range of the average operating speeds.
- the volumetric flow provided by the steering pump (product of specific delivery volume and rotational speed of the internal combustion engine) is sufficient to supply the steering actuator without the use of the accumulator.
- the specific delivery volume of the steering pump is measured, for example, in the case of a forklift after the flow, the steering actuator at a
- the steering pump can be designed as a fixed displacement pump, which is followed by a pressure-controlled, between two switching positions pressure compensator, wherein the steering pump in the first switching position of the pressure compensator with the steering actuator and in the second switching position connected to a tank.
- the steering pump is designed as a variable displacement pump.
- a demand flow control of the variable displacement pump enables the minimization of circulation losses.
- a working hydraulics with upstream control valve assembly is connected to the steering pump and the steering actuator, under certain conditions, energy from the working hydraulics can be fed into the steering hydraulics.
- energy from the working hydraulics can be fed into the steering hydraulics.
- a forklift it is possible to use potential energy of the height-adjustable load carrier and / or the load to load the accumulator and / or actuate the steering actuator.
- the mobile work machine according to the invention can be designed for example as a forklift.
- An internal combustion engine 1 drives a steering pump 2, whose delivery line 3 is connected to a recordable as a steering cylinder hydraulic steering actuator 4, which is actuated by an upstream steering control valve 5.
- a reservoir 7 Downstream of a check valve 6 opening in the direction of the steering actuator 4, a reservoir 7 is connected to the delivery line 3 and thus to the steering pump 2 and to the steering actuator 4.
- the circuit is supplemented by a pressure relief valve 8 and a filter 9 at the output of the steering pump 2.
- a pressure sensor 10 is provided which measures the pressure in the delivery line 3 downstream of the check valve 6 and thus also the pressure in the memory 7.
- the pressure sensor 10 is in operative connection with a brake system, not shown in the figures of the machine.
- the specific delivery volume of the steering pump 2, so the delivery volume per revolution, is dimensioned so that the operation of the steering actuator 4 below a certain threshold speed of the engine 1 only by parallel injection of pressure fluid from both the steering pump 2 and from the memory 7.
- the memory 7 is charged by the steering pump 2 in this operating condition.
- the steering pump 2 Upon reaching the threshold speed, the steering pump 2 promotes a volume flow sufficient to feed the steering actuator 4 without pressure medium from the memory 7. At higher operating speeds (above the threshold speed) 2 more pressure medium is funded by the steering pump than necessary for the actuation of the steering actuator 4. The excess pressure medium loads the memory 7 or is discharged via the pressure relief valve 8 in the tank.
- the pressure signal detected by the pressure sensor 10 triggers an emergency braking of the working machine in order to ensure that no dangerous driving conditions occur.
- the steering pump 2 designed as a fixed-displacement pump is followed by a pressure compensator 11, which is controlled by the pressure in the delivery line 3 is movable between two switching positions.
- the steering pump 2 is connected in the first switching position with the steering actuator 4 and in the second switching position with a tank T.
- the losses are reduced when the steering actuator 4 is not actuated.
- the pump is always set to the lowest possible delivery volume.
- FIG. 3 shows an embodiment of the invention in which, downstream of the check valve 6, a line 12 branches off from the delivery line 3 and leads to a cylinder of a working hydraulic system 13. This may be, for example, the lifting cylinder of a forklift.
- the working hydraulics 13 is preceded by a control valve assembly 14. With this variant of the invention it is in principle possible to use energy from the working hydraulics 13 (eg potential energy of a load) to operate the steering and / or to charge the memory 7.
- energy from the working hydraulics 13 eg potential energy of a load
Description
Die Erfindung betrifft eine mobile Arbeitmaschine, insbesondere Flurförderzeug, mit einem Verbrennungsmotor und einer davon angetriebenen hydraulischen Lenkpumpe zur Speisung eines Lenkaktuators.The invention relates to a mobile working machine, in particular industrial truck, with an internal combustion engine and a hydraulic steering pump driven therefrom for supplying a steering actuator.
Die Versorgung der Lenkanlage von verbrennungsmotorisch betriebenen Gabelstaplern mit hydraulischer Energie erfolgt durch eine Lenkpumpe, deren Fördervolumen an der unteren Leerlaufdrehzahl des Verbrennungsmotors bemessen ist. Bei dieser Drehzahl fördert die Lenkpumpe bereits ausreichend Druckmittel, um den Lenkaktuator so weit versorgen zu können, dass eine Mindestlenkgeschwindigkeit erreicht wird. Prinzipbedingt führt dies zu großvolumigen Lenkpumpen, die einen hohen Drehmomentbedarf aufweisen. Bei ansteigender Betriebsdrehzahl des Verbrennungsmotors entstehen erhebliche Energieverluste, da mehr Druckmittel von der Lenkpumpe gefördert wird als der Lenkaktuator benötigt. In Gabelstaplern, in denen die hydraulische Pumpe nicht nur den Lenkzylinder sondern auch eine Arbeitshydraulik versorgt (Prioritätsventilschaltung), wird immer das gesamte Druckmittel, also auch die für die Arbeitshydraulik benötigte Menge, unter Druck gesetzt. Auch dies führt zu Energieverlusten und zum Aufheizen des gesamten Hydrauliksystems.The supply of the steering system of internal combustion engine-powered forklifts with hydraulic energy is performed by a steering pump whose delivery volume is measured at the lower idle speed of the internal combustion engine. At this speed, the steering pump already promotes sufficient pressure fluid to supply the steering actuator so far that a minimum steering speed is achieved. Due to the principle, this leads to large-volume steering pumps, which have a high torque requirement. With increasing operating speed of the engine considerable energy losses occur because more pressure medium is conveyed by the steering pump than the steering actuator needed. In forklifts, in which the hydraulic pump supplies not only the steering cylinder but also a working hydraulics (priority valve switching), the entire pressure medium, including the quantity required for the working hydraulics, is always pressurized. This too leads to energy losses and to heating of the entire hydraulic system.
Aus der DE 199 55 312 A1 ist es bekannt, bei einem hydraulischen Getriebe für den Fahrantrieb eines Flurförderzeugs zwischen Pumpe und Motor einen Druckspeicher vorzusehen, der es ermöglicht, den hydraulischen Antrieb auch bei abgeschaltetem Verbrennungsmotor zu betreiben.From DE 199 55 312 A1 it is known to provide a hydraulic accumulator for the traction drive of a truck between the pump and motor pressure accumulator, which makes it possible to operate the hydraulic drive even when the internal combustion engine.
Der vorliegenden Erfindung liegt die Aufgabe zu Grunde, eine mobile Arbeitsmaschine der eingangs genannten Art zur Verfügung zu stellen, bei der die Energieverluste, die vom Lenksystem verursacht werden, minimiert sind.The present invention is based on the object to provide a mobile machine of the type mentioned above, in which the energy losses caused by the steering system are minimized.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, dass ein hydraulischer Speicher an die Lenkpumpe und den Lenkaktuator angeschlossen ist und dass das spezifische Fördervolumen der Lenkpumpe so bemessen ist, dass der Betrieb des Lenkaktuators bei geringen Betriebsdrehzahlen des Verbrennungsmotors das Einspeisen von Druckmittel aus der Lenkpumpe und dem Speicher erfordert und bei Überschreiten einer Schwellendrehzahl der Betrieb des Lenkzylinders durch alleiniges Einspeisen von Druckmittel aus der Lenkpumpe möglich ist.This object is achieved in that a hydraulic accumulator is connected to the steering pump and the steering actuator and that the specific delivery volume of the steering pump is so dimensioned that the operation of the steering actuator at low operating speeds of the internal combustion engine, the injection of pressure medium from the steering pump and the memory requires and when a threshold speed is exceeded, the operation of the steering cylinder by solely feeding pressure medium from the steering pump is possible.
Der erfindungswesentliche Gedanke besteht demnach darin, das spezifische Fördervolumen der Lenkpumpe, also das Fördervolumen pro Umdrehung, deutlich zu reduzieren und als Ausgleich einen ausreichend groß dimensionierten Speicher vorzusehen, der durch die Lenkpumpe geladen wird und aus dem in bestimmten Betriebszuständen, nämlich bei niedrigen Betriebsdrehzahlen des Verbrennungsmotors, zusätzlich zur Lenkpumpe Druckmittel in den Lenkaktuator eingespeist wird. Im Idealfall kann dadurch das Fördervolumen der Lenkpumpe halbiert bis gedrittelt werden. Damit werden die Energieverluste und der Drehmomentbedarf der Lenkpumpe im gleichen Maße reduziert. Die Lenkpumpe baut kleiner und benötigt weniger Platz in der Arbeitsmaschine.The idea essential to the invention is therefore to significantly reduce the specific delivery volume of the steering pump, so the delivery volume per revolution and compensate to provide a sufficiently large memory that is loaded by the steering pump and from the operating conditions in certain, namely at low operating speeds of Internal combustion engine, in addition to the steering pump pressure medium is fed into the steering actuator. Ideally, the delivery volume of the steering pump can be halved or even divided into three. This reduces the energy losses and the torque requirement of the steering pump to the same extent. The steering pump is smaller and requires less space in the machine.
Die Drehmomentanforderung an den Verbrennungsmotor sind besonders im Bereich niedriger Betriebsdrehzahlen verringert, was den Einsatz von klein bauenden Turbo-Motoren ermöglicht, die gerade in diesem Betriebsbereich eher drehmomentschwach sind. Insgesamt sind die Energieverluste im Lenkungskreislauf deutlich herabgesetzt.The torque demand on the internal combustion engine is reduced especially in the range of low operating speeds, which allows the use of small-sized turbo engines, which are rather weak in torque especially in this operating range. Overall, the energy losses in the steering circuit are significantly reduced.
Zweckmäßigerweise ist das Volumen des Speichers so bemessen, dass bei alleiniger Speisung des Lenkaktuators durch Druckmittel aus dem vollen Speicher ein mehrfaches Betätigen des Lenkaktuators von Anschlag zu Anschlag möglich ist. Dadurch ist eine Notenergieversorgung des Lenkaktuators bei Ausfall des Verbrennungsmotors oder der Lenkpumpe sichergestellt. Es bedarf dabei keiner zusätzlichen Kraftanstrengung des Fahrers der Arbeitsmaschine, um die Notenergieversorgung einzusetzen.Conveniently, the volume of the memory is so dimensioned that with sole supply of the steering actuator by pressure medium from the full memory multiple actuation of the steering actuator from stop to stop is possible. As a result, a Notenergieversorgung the steering actuator is ensured in case of failure of the engine or the steering pump. It requires no additional effort of the driver of the machine to use the emergency power supply.
Es erweist sich als günstig, wenn ein den Druck im Speicher direkt oder indirekt erfassender Drucksensor vorgesehen ist, der in Wirkverbindung mit einer Bremsanlage der Arbeitsmaschine steht, wobei bei Unterschreiten eines Druck-Grenzwertes ein zwangsgesteuerter Bremsvorgang auslösbar ist. Bei Druckverlust im Lenkungskreislauf wird die Arbeitsmaschine somit in einen sicheren Zustand gebracht.It proves to be advantageous if a pressure sensor in the memory directly or indirectly detected pressure sensor is provided, which is in operative connection with a brake system of the machine, which falls below a pressure limit, a positively controlled braking operation can be triggered. With pressure loss in the steering circuit, the working machine is thus brought into a safe state.
Die Schwellendrehzahl des Verbrennungsmotors liegt mit Vorteil im Bereich der mittleren Betriebsdrehzahlen. Hierbei reicht der von der Lenkpumpe zur Verfügung gestellte Volumenstrom (Produkt aus spezifischem Fördervolumen und Drehzahl des Verbrennungsmotors) aus, um ohne Einsatz des Speichers den Lenkaktuator zu versorgen. Das spezifische Fördervolumen der Lenkpumpe bemisst sich dabei beispielsweise im Falle eines Gabelstaplers nach dem Volumenstrom, den der Lenkaktuator bei einemThe threshold speed of the internal combustion engine is advantageously in the range of the average operating speeds. In this case, the volumetric flow provided by the steering pump (product of specific delivery volume and rotational speed of the internal combustion engine) is sufficient to supply the steering actuator without the use of the accumulator. The specific delivery volume of the steering pump is measured, for example, in the case of a forklift after the flow, the steering actuator at a
Staplerarbeitsspiel im Bereich dieser mittleren Betriebsdrehzahl des Verbrennungsmotors erfordert.Stacker working game in the range of this average operating speed of the internal combustion engine requires.
Um die Energieverluste weiter zu minmieren, kann gemäß einer vorteilhaften Ausgestaltung der Erfindung die Lenkpumpe als Konstantpumpe ausgebildet sein, der eine förderdruckgesteuerte, zwischen zwei Schaltstellungen bewegliche Druckwaage nachgeschaltet ist, wobei die Lenkpumpe in der ersten Schaltstellung der Druckwaage mit dem Lenkaktuator und in der zweiten Schaltstellung mit einem Tank verbunden ist.In order to further minimize the energy losses, according to an advantageous embodiment of the invention, the steering pump can be designed as a fixed displacement pump, which is followed by a pressure-controlled, between two switching positions pressure compensator, wherein the steering pump in the first switching position of the pressure compensator with the steering actuator and in the second switching position connected to a tank.
Eine andere, nicht minder günstige Ausgestaltung der Erfindung sieht vor, dass die Lenkpumpe als Verstellpumpe ausgebildet ist. Hierbei ermöglicht eine Bedarfsstromregelung der Verstellpumpe die Minimierung von Umlaufverlusten.Another, no less favorable embodiment of the invention provides that the steering pump is designed as a variable displacement pump. In this case, a demand flow control of the variable displacement pump enables the minimization of circulation losses.
Sofern eine Arbeitshydraulik mit vorgeschalteter Steuerventilanordnung an die Lenkpumpe und den Lenkaktuator angeschlossen ist, kann unter bestimmten Bedingungen Energie aus der Arbeitshydraulik in die Lenkhydraulik einspeist werden. So ist es beispielsweise bei einem Gabelstapler möglich, potentielle Energie des höhenbeweglichen Lastträgers und/oder der Last zu nutzen, um den Speicher zu laden und/oder den Lenkaktuator zu betätigen..If a working hydraulics with upstream control valve assembly is connected to the steering pump and the steering actuator, under certain conditions, energy from the working hydraulics can be fed into the steering hydraulics. For example, in a forklift, it is possible to use potential energy of the height-adjustable load carrier and / or the load to load the accumulator and / or actuate the steering actuator.
Weitere Vorteile und Einzelheiten der Erfindung werden anhand des in den schematischen Figuren dargestellten Ausführungsbeispieles näher erläutert. Dabei zeigt:
Figur 1- einen Schaltplan einer hydraulischen Lenkanlage einer erfindungsgemäßen mobilen Arbeitsmaschine,
Figur 2- eine erste Variante der Schaltung gemäß
Figur 1 und Figur 3- eine zweite Variante der Schaltung gemäß
Figur 1.
- FIG. 1
- a circuit diagram of a hydraulic steering system of a mobile work machine according to the invention,
- FIG. 2
- a first variant of the circuit according to Figure 1 and
- FIG. 3
- a second variant of the circuit according to FIG. 1
Die erfindungsgemäße mobile Arbeitsmaschine kann beispielsweise als Gabelstapler ausgebildet sein. Ein Verbrennungsmotor 1 treibt eine Lenkpumpe 2 an, deren Förderleitung 3 ein bespielsweise als Lenkzylinder ausgebildeter hydraulischer Lenkaktuator 4 angeschlossen ist, der durch ein vorgeschaltetes Lenksteuerventil 5 betätigbar ist.The mobile work machine according to the invention can be designed for example as a forklift. An
Stromab eines in Richtung zum Lenkaktuator 4 öffnenden Rückschlagventils 6 ist ein Speicher 7 an die Förderleitung 3 und somit an die Lenkpumpe 2 und an den Lenkaktuator 4 angeschlossen. Die Schaltung wird durch ein Druckbegrenzungsventil 8 und ein Filter 9 am Ausgang der Lenkpumpe 2 ergänzt. Ferner ist im vorliegenden Ausführungsbeispiel ein Drucksensor 10 vorgesehen, der den Druck in der Förderleitung 3 stromab des Rückschlagventils 6 misst und damit auch den Druck im Speicher 7. Der Drucksensor 10 steht mit einer in den Figuren nicht dargestellten Bremsanlage der Arbeitsmaschine in Wirkverbindung.Downstream of a
Das spezifische Fördervolumen der Lenkpumpe 2, also das Fördervolumen pro Umdrehung, ist so dimensioniert, dass der Betrieb des Lenkaktuators 4 unterhalb einer bestimmten Schwellendrehzahl des Verbrennungsmotors 1 nur durch parallele Einspeisung von Druckmittel sowohl aus der Lenkpumpe 2 als auch aus dem Speicher 7 erfolgt. Bei nicht betätigter Lenkung wird in diesem Betriebszustand der Speicher 7 von der Lenkpumpe 2 geladen.The specific delivery volume of the
Bei Erreichen der Schwellendrehzahl fördert die Lenkpumpe 2 einen Volumenstrom, der ausreicht, um den Lenkaktuator 4 ohne Druckmittel aus dem Speicher 7 zu speisen. Bei höheren Betriebsdrehzahlen (oberhalb der Schwellendrehzahl) wird von der Lenkpumpe 2 mehr Druckmittel gefördert als zur Betätigung des Lenkaktuators 4 nötig. Das überschüssige Druckmittel lädt den Speicher 7 oder wird über das Druckbegrenzungsventil 8 in den Tank abgelassen.Upon reaching the threshold speed, the
Fällt die Lenkpumpe 2 aus, so ist es bei vollem Speicher 7 noch möglich, den Lenkaktuator 4 mehrmals von Anschlag zu Anschlag zu betätigen. Aus Sicherheitsgründen ist es auch empfehlenswert, wie in Figur 1 dargestellt, die Energieversorgung des elektromagnetisch betätigbaren Lenksteuerventils 4 durch den Einsatz von Doppelmagneten M1, M2 zweikreisig auszuführen.If the
Sofern ein bestimmtes Druckniveau in der Förderleitung 3 unterschritten wird, löst das von dem Drucksensor 10 erfasste Drucksignal eine Zwangsbremsung der Arbeitsmaschine aus, um sicher zu stellen, dass keine gefährlichen Fahrzustände entstehen.If a certain pressure level in the
Bei der Variante gemäß Figur 2 ist der als Konstantpumpe ausgebildeten Lenkpumpe 2 eine vom Druck in der Förderleitung 3 gesteuerte Druckwaage 11 nachgeschaltet, die zwischen zwei Schaltstellungen beweglich ist. Hierbei ist die Lenkpumpe 2 in der ersten Schaltstellung mit dem Lenkaktuator 4 und in der zweiten Schaltstellung mit einem Tank T verbunden. Dadurch werden bei nicht betätigtem Lenkaktuator 4 die Verluste reduziert. Alternativ dazu ist es auch möglich, die Lenkpumpe 2 als Verstellpumpe auszubilden und mit einer Bedarfsstromregelung zu versehen. Hierbei wird die Pumpe stets auf ein möglichst geringes Fördervolumen eingestellt.In the variant according to FIG. 2, the
Figur 3 zeigt eine Ausgestaltung der Erfindung, bei der stromab des Rückschlagventils 6 von der Förderleitung 3 eine Leitung 12 abzweigt, die zu einem Zylinder einer Arbeitshydraulik 13 führt. Dabei kann es sich beispielsweise um den Hubzylinder eines Gabelstaplers handeln. Der Arbeitshydraulik 13 ist eine Steuerventilanordnung 14 vorgeschaltet. Mit dieser Variante der Erfindung ist es im Prinzip möglich, Energie aus der Arbeitshydraulik 13 (z. B. potentielle Energie einer Last) zum Betreiben der Lenkung und/oder zum Laden des Speichers 7 zu nutzen.FIG. 3 shows an embodiment of the invention in which, downstream of the
Claims (7)
- Mobile working machine, in particular industrial truck, having an internal combustion engine and a hydraulic steering pump driven thereby for feeding at least one steering actuator, characterized in that a hydraulic accumulator (7) is connected to the steering pump (2) and the steering actuator (4), and in that the specific delivery volume of the steering pump (2) is dimensioned such that the operation of the steering actuator (4) at low operating speeds of the internal combustion engine (1) requires pressure medium to be fed in from the steering pump (2) and the accumulator (7) and, when a threshold speed is exceeded, the operation of the steering actuator (4) is possible merely by feeding in pressure medium from the steering pump (2).
- Mobile working machine according to Claim 1, characterized in that the volume of the accumulator (7) is dimensioned such that, when the steering actuator (4) is fed alone by pressure medium from the full accumulator (7), it is possible to actuate the steering actuator (4) a plurality of times from stop to stop.
- Mobile working machine according to Claim 1 or 2, characterized in that a pressure sensor (10), which senses the pressure in the accumulator (7) directly or indirectly and is operatively connected to a braking system of the working machine, is provided, it being possible for a positively controlled braking operation to be triggered when the pressure falls below a pressure limit value.
- Mobile working machine according to one of Claims 1 to 3, characterized in that the threshold speed of the internal combustion engine (1) is in the region of the mean operating speeds.
- Mobile working machine according to one of Claims 1 to 4, characterized in that the steering pump (2) is in the form of a fixed displacement pump, downstream of which a pressure balance (11), which is controlled by delivery pressure and can move between two switching positions, is connected, the steering pump (2) being connected to the steering actuator (4) in the first switching position of the pressure balance (11) and to a tank (T) in the second switching position.
- Mobile working machine according to one of Claims 1 to 4, characterized in that the steering pump (2) is in the form of a variable displacement pump.
- Mobile working machine according to one of Claims 1 to 6, characterized in that working hydraulics (13) with an upstream control valve arrangement (14) are connected to the steering pump (2) and the steering cylinder (4).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2001145992 DE10145992A1 (en) | 2001-09-18 | 2001-09-18 | Mobile work machine with an internal combustion engine and a hydraulic steering pump driven by it |
| DE10145992 | 2001-09-18 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP1293669A2 EP1293669A2 (en) | 2003-03-19 |
| EP1293669A3 EP1293669A3 (en) | 2005-04-13 |
| EP1293669B1 true EP1293669B1 (en) | 2007-04-11 |
Family
ID=7699435
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP20020019785 Expired - Lifetime EP1293669B1 (en) | 2001-09-18 | 2002-09-04 | Hydraulic vehicle steering pump driven by combustion engine |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP1293669B1 (en) |
| DE (2) | DE10145992A1 (en) |
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| CN102305222B (en) * | 2011-08-24 | 2014-03-26 | 天津大学 | Electro-hydraulic variable valve device with energy accumulator buffer function and energy storage method thereof |
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| CN105644620A (en) * | 2016-04-05 | 2016-06-08 | 南京林业大学 | Energy-saving constant pressure type hydraulic power steering system |
| CN107246420A (en) * | 2017-07-20 | 2017-10-13 | 南京讯联智能科技有限公司 | It is a kind of to carry the integrated valve group of guide for blocking sender |
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Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB876727A (en) * | 1958-10-29 | 1961-09-06 | Clark Equipment Co | Hydraulic power transmission systems |
| US5222875A (en) * | 1991-05-31 | 1993-06-29 | Praxair Technology, Inc. | Variable speed hydraulic pump system for liquid trailer |
| DE19955312B4 (en) * | 1999-11-17 | 2005-10-27 | Jungheinrich Ag | Drive system for industrial trucks |
-
2001
- 2001-09-18 DE DE2001145992 patent/DE10145992A1/en not_active Withdrawn
-
2002
- 2002-09-04 DE DE50209903T patent/DE50209903D1/en not_active Expired - Fee Related
- 2002-09-04 EP EP20020019785 patent/EP1293669B1/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105545135A (en) * | 2015-02-28 | 2016-05-04 | 北京航空航天大学 | New principle cabin door transient actuating system based on constant displacement motor |
Also Published As
| Publication number | Publication date |
|---|---|
| DE10145992A1 (en) | 2003-04-03 |
| DE50209903D1 (en) | 2007-05-24 |
| EP1293669A2 (en) | 2003-03-19 |
| EP1293669A3 (en) | 2005-04-13 |
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