EP2980006B1 - Hydraulic system of a mobile work machine, in particular an industrial fork-lift truck - Google Patents

Hydraulic system of a mobile work machine, in particular an industrial fork-lift truck Download PDF

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Publication number
EP2980006B1
EP2980006B1 EP15179000.3A EP15179000A EP2980006B1 EP 2980006 B1 EP2980006 B1 EP 2980006B1 EP 15179000 A EP15179000 A EP 15179000A EP 2980006 B1 EP2980006 B1 EP 2980006B1
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EP
European Patent Office
Prior art keywords
pressure medium
valve
hydraulic system
control
charging
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.)
Not-in-force
Application number
EP15179000.3A
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German (de)
French (fr)
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EP2980006A1 (en
Inventor
Peter Magsaam
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.)
Linde Material Handling GmbH
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Linde Material Handling GmbH
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Publication of EP2980006A1 publication Critical patent/EP2980006A1/en
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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
    • 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
    • B66F9/12—Platforms; Forks; Other load supporting or gripping members
    • B66F9/14—Platforms; Forks; Other load supporting or gripping members laterally movable, e.g. swingable, for slewing or transverse movements
    • B66F9/146—Side shift, i.e. both forks move together sideways relative to fork support
    • 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7135—Combinations of output members of different types, e.g. single-acting cylinders with rotary motors

Definitions

  • the invention relates to a hydraulic system of a mobile work machine, in particular of a truck, with a working hydraulics comprising a lifting drive and a side slide, wherein the hydraulic system comprises a working hydraulic pump which is provided for supplying the lifting drive with pressure medium, wherein the hydraulic system comprises a pressure fluid reservoir.
  • a hydraulic system of a truck is out of the DE 102 24 731 B4 known.
  • Work machines designed as industrial trucks have working hydraulics which, as consumers, are a lifting drive for lifting and lowering a load receiving means, for example a forklift, a tilting drive for tilting the load receiving means or a lifting frame on which the load receiving means can be raised and lowered, and one or more Additional consumer includes.
  • the additional consumers are usually formed by different attachments with which additional function of the lifting device are controllable, for example, a side slide for lateral displacement of the lifting device, or a rotating device for rotating the lifting device.
  • the additional consumers can have different demands on the pressure and the flow rate and thus the volume flow requirement.
  • a side shifter has a relatively low flow rate, whereas a rotary device requires a relatively high flow rate.
  • the lifting drive, the tilt drive and the additional consumers are each controllable by means of a control path valve which communicates with the supply line of the working hydraulic pump for the supply of pressure medium.
  • control valves for controlling the linear actuator, the tilt drive and the additional consumers are in this case installed in a control valve block, for example, a Monoventilblock cast or layered construction of brazed segment plates, the control way valve of the additional consumer is designed for the additional consumer with the largest possible flow rate.
  • the working hydraulics is usually provided with an inlet pressure compensator, which is controlled by the highest load pressure of the load of the working hydraulics and allows the working hydraulic pump promotes non-actuated consumers in a single circulation to a container and funded actuated by consumers of the working hydraulic pump Excessive volume flow that exceeds the demand of the consumers of the working hydraulics can be discharged to the container.
  • the DE 199 03 174 A1 discloses an attachment designed as a side slide, which supplies pressure medium from a pressure medium accumulator arranged in the lifting slide becomes.
  • the arranged in the lifting pressure fluid accumulator is mitaufêt during lifting of the lifting cylinder with pressure medium.
  • the present invention has for its object to provide a hydraulic system of the type mentioned is available, which is improved in terms of energy efficiency in the operation of the side shifter.
  • the accumulator is charged by means of a charging circuit of the working hydraulic pump with pressure medium, wherein the charging circuit has a biasing valve, which ensures the preferred supply of pressure fluid accumulator with pressure medium of the working hydraulic pump, the bias valve on the input side with a delivery line of the hydraulic pump in Connection stands and the biasing valve is connected on the output side to a supply line leading to control valves of the working hydraulics as well as to a charge line guided to the accumulator, wherein the side shifter is connected to the accumulator for supplying pressure medium.
  • the supply of the side slide is thus detached from the working hydraulic pump with pressure medium from the accumulator, which was charged by the working hydraulic pump with pressure medium.
  • the side shifter can be supplied as required with the required volume flow and the required amount of pressure medium, so that the sole operation of the side slide throttling an excess amount of the inlet pressure compensator and the associated energy losses are avoided.
  • the heat input into the pressure medium is also reduced in the invention, whereby further a low cooling demand for the pressure medium can be achieved.
  • the supply of the side shifter according to the invention has a high energy efficiency.
  • the side shifter is controllable by means of a control path valve which is connected to the supply of pressure fluid to supply with pressure medium.
  • a control way valve With a control way valve, the moving speed and the moving direction of the side shifter can be easily controlled.
  • the control valve to the flow rate requirement and thus the flow rate demand adapt the side shifter and interpreted accordingly, so that in the invention, an improved metering of the movement of the side shifter by the operation and deflection of a setpoint specification device, such as a joystick can be achieved.
  • the charging circuit of the pressure medium accumulator on the charging line which is connectable to charge the accumulator with the delivery line of the working hydraulic pump, wherein in the charging line a check valve, in particular, a check valve opening in the direction of the accumulator is arranged, wherein the control path valve of the side shifter is connected to the supply of pressure medium from the accumulator to the charge line between the accumulator and the check valve.
  • a check valve in particular, a check valve opening in the direction of the accumulator is arranged
  • the control path valve of the side shifter is connected to the supply of pressure medium from the accumulator to the charge line between the accumulator and the check valve.
  • control valve of the side valve is electrically actuated, wherein an electronic control device is provided for driving the control path valve of the side shifter, the input side with a set point for the side shifter, such as a joystick, is in active connection.
  • control path valve of the side slide by means of an electrical actuating device, such as electromagnets, actuated, directly actuate a spool of the control valves.
  • an electrical actuating device such as electromagnets, actuated
  • directly actuate a spool of the control valves directly actuate a spool of the control valves.
  • the charging circuit of the accumulator is installed in a storage charging section and the control path valve of the side shifter installed in the accumulator charging section.
  • the construction cost can be further reduced and it is achieved that at one the control valves of the remaining consumers the Hydraulic control valve block containing no changes to the installation of the control valves of the side valve are required.
  • the accumulator charging section is attached to a control valve block of the working hydraulics.
  • Such coding can be formed according to an advantageous embodiment of the invention of special fittings.
  • special fittings for the consumer connections of the control valves and the side valve can be achieved in a simple manner that only the side shifter can be connected to the control valves of the side valve of the hydraulic system according to the invention.
  • the hydraulic system comprises a hydraulic steering device and the pressure medium reservoir is provided for supplying the steering device with pressure medium.
  • the accumulator thus continues to serve to supply a hydraulic steering device of the working machine, whereby the energy efficiency of the hydraulic system can be further improved.
  • FIG. 1 is a hydraulic circuit diagram of a hydraulic system 1 according to the invention a mobile machine, for example, designed as a counterbalanced forklift truck illustrated.
  • the hydraulic system 1 of the industrial truck comprises a working hydraulics 2, a hydraulic steering device 3 and a hydraulic braking device 4.
  • the hydraulic system 1 of the industrial truck further comprises a hydrostatic drive 5 of the industrial truck.
  • the hydrostatic drive 5 comprises a drive pump 6, which is connected in a closed circuit to traction motors 7a, 7b which are in operative connection with the driven wheels 9a, 9b of the industrial truck.
  • the drive pump 6 is designed as a variable displacement in the variable displacement pump, to the adjustment of the delivery volume, an adjusting device 10 is provided.
  • the closed circuit of the hydrostatic drive is further provided with a feed device 11.
  • the adjusting device 10 and the feeding device 11 are connected to the supply of pressure medium with a supply line 12 in connection.
  • the hydraulic steering device 3 comprises a hydraulic steering cylinder 15 which can be actuated by means of a steering valve 16.
  • the steering valve 16 is formed in the illustrated embodiment as Lenkorbitrol, which is mechanically actuated and is for actuating with a steering actuator 17, such as a steering wheel, in mechanical operative connection.
  • the steering valve 16 is connected to the supply of pressure medium with a supply line 18 in connection.
  • An output of the steering valve 16 is connected to a guided to a container 20 drain line 19.
  • the hydraulic braking device 4 has a load 30 as a consumer, for example, a spring brake, which is associated with the driven wheels 9a, 9b and by means of a brake valve 31 is actuated.
  • the brake valve 31 is formed in the illustrated embodiment as a mechanically actuated pressure control valve which controls the brake release pressure in a brake line 32 which is connected to a force acting in the direction of a release position pressure chamber of the spring brake.
  • the brake valve 31 is for actuating with a brake actuator 33, such as a brake pedal, in mechanical operative connection.
  • the brake valve 31 is connected to a supply line 34, to a guided to the container 20 drain line 35 and to the brake pipe 32.
  • the working hydraulics 2 comprises in the illustrated embodiment, a lifting drive 40, a tilt drive 41 and a side gate 43 as hydraulic consumers. Furthermore, the working hydraulics 2 may include an additional consumer 42 as a further hydraulic consumer.
  • a working hydraulic pump 45 is provided, which is driven by a drive motor 46.
  • the drive motor 46 is formed in the illustrated embodiment as an internal combustion engine. However, it is alternatively possible to execute the drive motor 46 as an electric motor.
  • the drive motor 46 continues to drive the drive pump 6 of the hydrostatic drive 5.
  • the drive motor 46 further serves to drive an auxiliary pump 47, which serves to supply the braking device 4, the adjusting device 10 of the drive pump 6 and the feed device 11 of the hydrostatic drive 5.
  • the auxiliary pump 47 is operated in the open circuit and sucks pressure medium via a suction line 48 from the container 20 and promotes the pressure medium in a delivery line 49 to which the supply line 34 of the braking device 4 and the supply line 12 of the adjusting device 10 and the feeding device 11 are connected ,
  • the working hydraulic pump 45 is operated in an open circuit and sucks pressure medium via a suction line 48 from the container 20 and conveys the pressure medium in a delivery line 50.
  • the delivery line 50 is connected to a port P of Control valve block 51 of the working hydraulics 2 connected.
  • the working hydraulic pump 45 is formed as adjustable in the delivery volume variable displacement pump, to whose adjustment of the delivery volume, an adjusting device 45a is provided. For supply with pressure medium, the adjusting device 45a is connected to the delivery line 49 of the auxiliary pump 47.
  • the control valve block 51 of the working hydraulics 2 includes a control-way valve 52 for controlling the lifting drive 40, a control-way valve 53 for controlling the tilting drive 41, and a control-way valve 54 for controlling the optional additional consumer 42.
  • the port P is in the control valve block 51 - as in FIG. 2 can be seen - connected to a supply line 60, to which by means of appropriate prinzweig effeten the control valves 52, 53, 54 are connected.
  • a port T of the control valve block 51 to which a tank line 61 led to the tank 20 is connected, communicates in the control valve block 51 with a tank line 62 to which the control directional valves 52, 53, 54 are connected by means of tank branch lines.
  • the control travel valve 52, 53, 54 are designed as load-sensing directional control valves, wherein upon activation of the control travel valves 52, 53, 54 and thus an actuation of the consumer 40, 41, 42, the highest load pressure is reported in a load pressure reporting line 63 of the working hydraulics 2 ,
  • the control valves 52, 53, 54 are designed as pilot-operated control valves and each electro-hydraulically actuated.
  • electrically actuatable pilot valves 52a, 52b are provided for actuating the control travel valve 52
  • electrically actuatable pilot valves 53a, 53b are provided for actuating the control travel valve 53
  • electrically actuatable pilot valves 54a, 54b are provided for actuating the control travel valve 54.
  • the pilot valves 52a, 52b, 53a, 53b, 54a, 54b are designed, for example, as pressure-reducing valves which can be actuated by means of a proportional magnet.
  • the pilot valves 52a, 52b, 53a, 53b, 54a, 54b are on the input side to supply with a control pressure with a control pressure line 68 of the control valve block 51 in connection, which is guided to a port Z of the control valve block 51. Via a supply line 69 connected to the connection Z, the control pressure line 68 communicates with the delivery line 49 of the auxiliary pump 47. at an electric control and thus an operation to generate the pilot valves 52a, 52b, 53a, 53b, 54a, 54b from the pending in the control pressure line 68 control pressure an actuating pressure, the corresponding control way valve 52, 53, 54 in a corresponding control position for actuating the consumer 40th , 41, 42 charged.
  • the load pressure detection line 63 is guided to a flow control device 70 of the control valve block 51.
  • the flow control device 70 is designed as an inlet pressure balance, which is arranged in a connecting line 71 connecting the feed line 60 with the tank line 62.
  • the inlet pressure compensator is in this case acted upon in the direction of a blocking position by the load pressure of the consumers 40, 41, 42 present in the load pressure signaling line 63 and a spring 72. In the direction of a flow position, the inlet pressure compensator can be acted upon by the delivery pressure present in the feed line 60.
  • the control valve block 51 has a release valve 73 for releasing the control travel valves 52, 53, 54 and the corresponding movements of the consumers 40, 41, 42.
  • the release valve 73 controls the control pressure line 68 and the load pressure detection line 63 and is electrically actuated.
  • the hydraulic system 1 comprises a pressure medium reservoir 80, which serves to supply the side slide 43 with pressure medium and which can be connected to the working hydraulic pump 2 for charging with pressure medium to the working hydraulic pump.
  • a charging circuit 81 For loading the accumulator 50, a charging circuit 81 is provided.
  • the charging circuit 81 is installed in a accumulator charging section 82 which is attached to the control valve block 51 of the working hydraulic system 2.
  • the charging circuit 81 has a biasing valve 84, which ensures the preferred supply of the accumulator 80 with pressure medium of the working hydraulic pump 45.
  • the biasing valve 84 is the input side to the delivery line 50 of the working hydraulic pump 45 in connection.
  • the biasing valve 84 is the output side to the guided to the control directional valves 52, 53, 54 of the working hydraulics 2 Inlet line 60 and connected to a guided to the accumulator 80 charge line 83.
  • a charging valve 85 of the charging circuit 81 is arranged, by means of which the loading operation of the pressure medium accumulator 80 is controllable.
  • the charging valve 85 is formed in the illustrated embodiment as an electrically controllable pressure reducing valve.
  • the pressure reducing valve is connected at one connection to the section of the charge line 83 guided to the pretensioning valve 84 and at another connection to the section of the charge line 83 leading to the pressure medium reservoir 80.
  • a further connection of the pressure reducing valve is connected to the container line 62.
  • the charging valve 85 is connected to the control with an electronic control device 90 in operative connection.
  • a pressure sensor 91 is provided, which communicates with the electronic control device 90.
  • check valve 89 is arranged in the illustrated embodiment as a check valve, such as spring-biased check valve.
  • the side shifter 43 is controllable by means of a control valve 100 which is connected to the pressure medium accumulator 80 for supply with pressure medium.
  • the control valve 100 of the side valve 43 is connected to the supply of pressure medium from the accumulator 80 by means of a supply line 101 to the charging line 83 between the accumulator 80 and the check valve 89. Further connections of the control-way valve 100 are connected by means of a drain line 102 to the tank line 62 of the control valve block 51.
  • the side shifter 43 is designed as a double-acting consumer, to whose connection to the control-way valve 100 hydraulic connections A4, B4 are provided.
  • the control-way valve 100 is designed as a longitudinal slide valve with a spool.
  • the control-way valve 100 has a neutral position 100a in the form of a middle position, in which the supply line 101, the discharge line 102 and the hydraulic connections A4, B4 are shut off.
  • a first control position 100b the supply line 101 is connected to the hydraulic connection A4 and the discharge line 102 is connected to the hydraulic connection B4.
  • a second control position 100c the supply line 101 is connected to the hydraulic port B4 and the drain line 102 to the hydraulic port A4.
  • the control-way valve 100 is designed as a proportional valve throttling in intermediate positions.
  • the hydraulic connections A4, B4 in the invention include a coding, for example by means of special fittings, which allows only the connection of the side shifter 43 to the control-way valve 100.
  • the control-way valve 100 of the side shifter 43 is electrically operated.
  • the control-way valve 100 of the side-shifter 43 is connected to the electronic control device 90 for activation.
  • the control device 90 is on the input side with a setpoint input device 105 for the side shifter, such as a joystick in operative connection.
  • the additional consumer 42 can be controlled in a second direction of movement.
  • another setpoint input device 106 such as a joystick in combination.
  • the control travel valve 100 of the side slider 43 is acted upon by springs in the neutral position 100a.
  • two electromagnets 104a, 104b are provided in the illustrated embodiment as an electrical actuating device, which actuate and deflect the spool of the control travel valve 100 directly.
  • the control-way valve 100 of the side shifter 43 is disposed and installed in the accumulator charging section 82 together with the valves of the charging circuit 81 of the accumulator 80.
  • the pressure fluid accumulator 80 continues to supply the hydraulic steering device 3 with pressure medium.
  • the supply line 18 of the steering device 3 is connected to the charging line 83 between the check valve 89 and the accumulator 80.
  • the supply according to the invention of the side slide 43 with pressure medium from the pressure medium reservoir 80 of the hydraulic system 1 has a number of advantages.
  • the control-way valve 100 of the side-shifter 43 can be adapted and adjusted to the flow-rate requirement of the side-shifter 43, whereby a good metering of the movements of the side-shifter 43 can be achieved by deflection of the setpoint-setting device 105. Since the side slider 43 has only a small volume flow requirement, results in a small and compact design control travel valve 100, which allows a reduction in the space of the control valve block 51 compared to hydraulic systems of the prior art.
  • the side shifter 43 can be supplied with the required quantity of pressure medium from the accumulator 80 when the control travel valve 100 is activated. Restricting excess flow rate of the working hydraulic pump 45 to the input pressure compensator 70 is prevented, which results in advantages in terms of energy efficiency. In addition, the heat input is reduced in the pressure medium of the hydraulic system 1, whereby the cooling demand decreases.
  • the side shifter 43 can be operated in parallel and independently to a charging operation of the accumulator 80 by the working hydraulic pump 45.
  • control path valve 100 of the side gate 43 in the accumulator charging section 82 offers advantages in the design of the control valve block 51 of the working hydraulics 2, since the control valve block 51 remains unchanged in variants of trucks with or without sideshift 43.

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Structural Engineering (AREA)
  • Civil Engineering (AREA)
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Description

Die Erfindung betrifft eine Hydraulikanlage einer mobilen Arbeitsmaschine, insbesondere eines Flurförderzeugs, mit einer Arbeitshydraulik, die einen Hubantrieb und einen Seitenschieber umfasst, wobei die Hydraulikanlage eine Arbeitshydraulikpumpe aufweist, die zur Versorgung des Hubantriebs mit Druckmittel vorgesehen ist, wobei die Hydraulikanlage einen Druckmittelspeicher umfasst.The invention relates to a hydraulic system of a mobile work machine, in particular of a truck, with a working hydraulics comprising a lifting drive and a side slide, wherein the hydraulic system comprises a working hydraulic pump which is provided for supplying the lifting drive with pressure medium, wherein the hydraulic system comprises a pressure fluid reservoir.

Eine Hydraulikanlage eines Flurförderzeugs ist aus der DE 102 24 731 B4 bekannt.A hydraulic system of a truck is out of the DE 102 24 731 B4 known.

Als Flurförderzeuge ausgebildete Arbeitsmaschinen weisen eine Arbeitshydraulik auf, die als Verbraucher einen Hubantrieb zum Heben und Senken eines Lastaufnahmemittels, beispielsweise einer Lastgabel, einen Neigeantrieb zum Neigen des Lastaufnahmemittels bzw. eines Hubgerüstes, an dem das Lastaufnahmemittel anhebbar und absenkbar angeordnet ist, und einen oder mehrere Zusatzverbraucher umfasst. Die Zusatzverbraucher sind in der Regel von unterschiedlichen Anbaugeräten gebildet, mit denen Zusatzfunktion des Lastaufnahmemittels steuerbar sind, beispielsweise ein Seitenschieber zum seitlichen Verschieben des Lastaufnahmemittels, oder ein Drehgerät zum Drehen des Lastaufnahmemittels. Die Zusatzverbraucher können hierbei unterschiedliche Anforderungen an den Druck und die Durchflussmenge und somit den Volumenstrombedarf aufweisen. Ein Seitenschieber weist eine relativ geringe Durchflussmenge auf, wohingegen ein Drehgerät eine relativ hohe Durchflussmenge benötigt. Bei bekannten Hydraulikanlagen sind der Hubantrieb, der Neigeantrieb und die Zusatzverbraucher jeweils mittels eines Steuerwegeventils steuerbar, das zur Versorgung mit Druckmittel mit der Förderleitung der Arbeitshydraulikpumpe in Verbindung steht.Work machines designed as industrial trucks have working hydraulics which, as consumers, are a lifting drive for lifting and lowering a load receiving means, for example a forklift, a tilting drive for tilting the load receiving means or a lifting frame on which the load receiving means can be raised and lowered, and one or more Additional consumer includes. The additional consumers are usually formed by different attachments with which additional function of the lifting device are controllable, for example, a side slide for lateral displacement of the lifting device, or a rotating device for rotating the lifting device. The additional consumers can have different demands on the pressure and the flow rate and thus the volume flow requirement. A side shifter has a relatively low flow rate, whereas a rotary device requires a relatively high flow rate. In known hydraulic systems, the lifting drive, the tilt drive and the additional consumers are each controllable by means of a control path valve which communicates with the supply line of the working hydraulic pump for the supply of pressure medium.

Die Steuerwegeventile zur Steuerung des Hubantriebs, des Neigeantriebs und der Zusatzverbraucher sind hierbei in einem Steuerventilblock eingebaut, beispielsweise einem Monoventilblock aus Guss oder in Schichtventilbauweise aus gelöteten Segmentblechen, wobei das Steuerwegeventil des Zusatzverbrauchers auf den Zusatzverbraucher mit dem größtmöglichen Durchflussmengenbedarf ausgelegt ist.The control valves for controlling the linear actuator, the tilt drive and the additional consumers are in this case installed in a control valve block, for example, a Monoventilblock cast or layered construction of brazed segment plates, the control way valve of the additional consumer is designed for the additional consumer with the largest possible flow rate.

Dadurch entstehen beim Anschluss eines Zusatzverbrauchers mit einem kleinen Durchflussmengenbedarf, beispielsweise eines Seitenschiebers, an das Steuerwegeventil des Zusatzverbrauchers, das auf den Zusatzverbraucher mit dem größtmöglichen Durchflussmengenbedarf ausgelegt ist, eine schlechte Dosierbarkeit der Bewegung des Seitenschiebers, da die erforderliche Durchflussmenge für den Seitenschieber bereits bei kleinen Auslenkungen des Steuerwegeventils und somit bei kleinen Auslenkungen an einer Sollwertvorgabeeinrichtung, beispielsweise einem Joystick, erreicht wird.This results in the connection of an additional consumer with a small flow requirement, such as a side valve to the control way valve of the additional consumer, which is designed for the additional consumer with the largest possible flow rate, poor metering the movement of the side slide, since the required flow for the side shifter already at small Deflections of the control valve and thus at small deflections to a setpoint input device, such as a joystick, is achieved.

Bei bekannten Hydraulikanlagen ist in der Regel die Arbeitshydraulik mit einer Eingangsdruckwaage versehen, die vom höchsten Lastdruck der Verbraucher der Arbeitshydraulik gesteuert ist und ermöglicht, dass die Arbeitshydraulikpumpe bei nicht betätigten Verbrauchern in einem Umlauf zu einem Behälter fördert und bei betätigten Verbrauchern der von der Arbeitshydraulikpumpe geförderte Überschussvolumenstrom, der den Bedarf der Verbraucher der Arbeitshydraulik übersteigt, zu dem Behälter abgeführt werden kann. Sofern bei bekannten Hydraulikanlagen, bei denen der Seitenschieber von der Arbeitshydraulikpumpe mit Druckmittel versorgt wird und das Steuerwegeventil des Seitenschiebers an die Förderleitung der Arbeitshydraulikpumpe angeschlossen ist, nur der Seitenschieber betätigt wird, wird der gesamte von der Arbeitshydraulikpumpe geförderte und im Umlauf befindliche Förderstrom, der sich aus dem Fördervolumen und der Drehzahl der Arbeitshydraulikpumpe ergibt, auf den Lastdruck des Seitenschiebers hochgezogen und der von dem Seitenschieber nicht benötigte Förderstrom der Arbeitshydraulikpumpe und somit die von der Arbeitshydraulikpumpe geförderte Überschussmenge, die den Bedarf des Seitenschiebers übersteigt, an der Eingangsdruckwaage unter Druckverlust zum Behälter abgedrosselt. Beim alleinigen Betrieb des Seitenschiebers entstehen bei bekannten Hydraulikanlagen durch das Abdrosseln des größten Teils des Förderstroms der Arbeitshydraulikpumpe zum Behälter hohe Energieverluste und ein hoher Wärmeeintrag in das Druckmittel der Hydraulikanlage, so dass sich weiterhin ein hoher Kühlbedarf mit einem entsprechenden hohen Energieverbrauch für eine Kühlereinrichtung des Druckmittels ergibt.In known hydraulic systems, the working hydraulics is usually provided with an inlet pressure compensator, which is controlled by the highest load pressure of the load of the working hydraulics and allows the working hydraulic pump promotes non-actuated consumers in a single circulation to a container and funded actuated by consumers of the working hydraulic pump Excessive volume flow that exceeds the demand of the consumers of the working hydraulics can be discharged to the container. If in known hydraulic systems in which the sideshifter is supplied by the working hydraulic pump with pressure medium and the control path valve of the side slider is connected to the delivery line of the working hydraulic pump, only the side shifter is actuated, the entire funded by the working hydraulic pump and circulating flow, the itself from the delivery volume and the speed of the working hydraulic pump, pulled up to the load pressure of the sideshift and the flow of the working hydraulic pump not required by the side shifter and thus the funded by the working hydraulic pump excess amount that exceeds the needs of the side shifter throttled at the inlet pressure compensator under pressure loss to the container , In the sole operation of the sideshift occur in known hydraulic systems by throttling most of the flow of the working hydraulic pump to container high energy losses and high heat input into the pressure medium of the hydraulic system, so that continues to be a high cooling demand with a corresponding high energy consumption for a cooler means of the pressure medium results.

Die DE 199 03 174 A1 offenbart ein als Seitenschieber ausgebildetes Anbaugerät, das von einem im Hubschlitten angeordneten Druckmittelspeicher mit Druckmittel versorgt wird. Der im Hubschlitten angeordnete Druckmittelspeicher wird beim Heben von dem Hebenzylinder mit Druckmittel mitaufgeladen.The DE 199 03 174 A1 discloses an attachment designed as a side slide, which supplies pressure medium from a pressure medium accumulator arranged in the lifting slide becomes. The arranged in the lifting pressure fluid accumulator is mitaufgeladen during lifting of the lifting cylinder with pressure medium.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, eine Hydraulikanlage der eingangs genannten Gattung zur Verfügung zu stellen, die hinsichtlich der Energieeffizient beim Betrieb des Seitenschiebers verbessert ist.The present invention has for its object to provide a hydraulic system of the type mentioned is available, which is improved in terms of energy efficiency in the operation of the side shifter.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, dass der Druckmittelspeicher mittels einer Ladeschaltung von der Arbeitshydraulikpumpe mit Druckmittel aufladbar ist, wobei die Ladeschaltung ein Vorspannventil aufweist, das die bevorzugte Versorgung des Druckmittelspeichers mit Druckmittel der Arbeitshydraulikpumpe sicherstellt, wobei das Vorspannventil eingangsseitig mit einer Förderleitung der Arbeitshydraulikpumpe in Verbindung steht und das Vorspannventil ausgangsseitig an eine zu Steuerwegeventilen der Arbeitshydraulik geführten Zulaufleitung sowie an eine zu dem Druckmittelspeicher geführte Ladeleitung angeschlossen ist, wobei der Seitenschieber zur Versorgung mit Druckmittel an den Druckmittelspeicher angeschlossen ist. Erfindungsgemäß erfolgt somit die Versorgung des Seitenschiebers losgelöst von der Arbeitshydraulikpumpe mit Druckmittel aus dem Druckmittelspeicher, der von der Arbeitshydraulikpumpe mit Druckmittel aufgeladen wurde. Hierdurch kann der Seitenschieber bedarfsgerecht mit dem benötigten Volumenstrom und der benötigten Druckmittelmenge versorgt werden, so dass bei der alleinigen Betätigung des Seitenschiebers das Abdrosseln einer Überschussmenge an der Eingangsdruckwaage und die damit einhergehenden Energieverluste vermieden werden. Durch das Verhindern des Abdrosselns einer Überschussmenge an der Eingangsdruckwaage beim Betrieb des Seitenschiebers wird bei der Erfindung zudem der Wärmeeintrag in das Druckmittel verringert, wodurch weiterhin ein geringer Kühlbedarf für das Druckmittel erzielbar ist. Insgesamt weist somit die erfindungsgemäße Versorgung des Seitenschiebers eine hohe Energieeffizient aus.This object is achieved in that the accumulator is charged by means of a charging circuit of the working hydraulic pump with pressure medium, wherein the charging circuit has a biasing valve, which ensures the preferred supply of pressure fluid accumulator with pressure medium of the working hydraulic pump, the bias valve on the input side with a delivery line of the hydraulic pump in Connection stands and the biasing valve is connected on the output side to a supply line leading to control valves of the working hydraulics as well as to a charge line guided to the accumulator, wherein the side shifter is connected to the accumulator for supplying pressure medium. According to the invention, the supply of the side slide is thus detached from the working hydraulic pump with pressure medium from the accumulator, which was charged by the working hydraulic pump with pressure medium. As a result, the side shifter can be supplied as required with the required volume flow and the required amount of pressure medium, so that the sole operation of the side slide throttling an excess amount of the inlet pressure compensator and the associated energy losses are avoided. By preventing the throttling of an excess amount at the inlet pressure compensator during operation of the side slide, the heat input into the pressure medium is also reduced in the invention, whereby further a low cooling demand for the pressure medium can be achieved. Overall, therefore, the supply of the side shifter according to the invention has a high energy efficiency.

Gemäß einer vorteilhaften Ausgestaltungsform der Erfindung ist der Seitenschieber mittels eines Steuerwegeventils steuerbar, das zur Versorgung mit Druckmittel an den Druckmittelspeicher angeschlossen ist. Mit einem Steuerwegeventil kann auf einfache Weise die Bewegungsgeschwindigkeit und die Bewegungsrichtung des Seitenschiebers gesteuert werden. Zudem wird es bei der Erfindung ermöglicht, das Steuerwegeventil an den Durchflussmengenbedarf und somit den Volumenstrombedarf des Seitenschiebers anzupassen und entsprechend auszulegen, so dass sich bei der Erfindung eine verbesserte Dosierbarkeit der Bewegung des Seitenschiebers durch die Betätigung und Auslenkung einer Sollwertvorgabeeinrichtung, beispielsweise eines Joysticks, erzielen lässt.According to an advantageous embodiment of the invention, the side shifter is controllable by means of a control path valve which is connected to the supply of pressure fluid to supply with pressure medium. With a control way valve, the moving speed and the moving direction of the side shifter can be easily controlled. In addition, it is possible in the invention, the control valve to the flow rate requirement and thus the flow rate demand adapt the side shifter and interpreted accordingly, so that in the invention, an improved metering of the movement of the side shifter by the operation and deflection of a setpoint specification device, such as a joystick can be achieved.

Vorteilhafterweise weist die Ladeschaltung des Druckmittelspeichers die Ladeleitung auf, die zum Laden des Druckmittelspeichers mit der Förderleitung der Arbeitshydraulikpumpe verbindbar ist, wobei in der Ladeleitung ein Sperrventil, insbesondere ein in Richtung zum Druckmittelspeicher öffnendes Rückschlagventil, angeordnet ist, wobei das Steuerwegeventil des Seitenschiebers zur Versorgung mit Druckmittel aus dem Druckmittelspeicher an die Ladeleitung zwischen dem Druckmittelspeicher und dem Sperrventil angeschlossen ist. Mit einer derartigen Ladeleitung kann der Druckmittelspeicher auf einfache Weise von der Arbeitshydraulikpumpe mit Druckmittel aufgeladen werden. Das in der Ladeleitung angeordnete Sperrventil verhindert auf einfache Weise, dass sich der Druckmittelspeicher über die Ladeleitung enthalten kann. Der Anschluss des Steuerwegeventils des Seitenschiebers an die Ladeleitung zwischen dem Sperrventil und dem Druckmittelspeicher ermöglicht es, dass der Seitenschieber unabhängig von der Arbeitshydraulikpumpe und auch während des Ladevorgangs des Druckmittelspeichers und somit parallel und unabhängig zu dem Ladevorgang des Druckmittelspeichers betrieben werden kann.Advantageously, the charging circuit of the pressure medium accumulator on the charging line, which is connectable to charge the accumulator with the delivery line of the working hydraulic pump, wherein in the charging line a check valve, in particular, a check valve opening in the direction of the accumulator is arranged, wherein the control path valve of the side shifter is connected to the supply of pressure medium from the accumulator to the charge line between the accumulator and the check valve. With such a charging line, the accumulator can be charged in a simple manner by the working hydraulic pump with pressure medium. The arranged in the charging line check valve prevents in a simple manner that the accumulator can contain the charge line. The connection of the control valves of the side valve to the charging line between the check valve and the accumulator allows the side shifter can be operated independently of the working hydraulic pump and during the charging of the accumulator and thus parallel and independent to the charging of the accumulator.

Hinsichtlich eines geringen Bauaufwandes ergeben sich besondere Vorteile, wenn gemäß einer vorteilhaften Ausführungsform der Erfindung das Steuerwegeventil des Seitenschiebers elektrisch betätigbar ist, wobei zur Ansteuerung des Steuerwegeventil des Seitenschiebers eine elektronische Steuereinrichtung vorgesehen ist, die eingangsseitig mit einer Sollwertvorgabeeinrichtung für den Seitenschieber, beispielsweise einem Joystick, in Wirkverbindung steht.With regard to a low construction cost, there are special advantages if, according to an advantageous embodiment of the invention, the control valve of the side valve is electrically actuated, wherein an electronic control device is provided for driving the control path valve of the side shifter, the input side with a set point for the side shifter, such as a joystick, is in active connection.

Vorteilhafterweise ist gemäß einer zweckmäßigen Ausgestaltungsform der Erfindung das Steuerwegeventil des Seitenschiebers mittels einer elektrischen Betätigungseinrichtung, beispielsweise Elektromagneten, betätigbar, die einen Steuerschieber des Steuerwegeventils direkt betätigen. Hierdurch kann der Bauaufwand weiter verringert werden, da ein derartiges direkt elektrisch betätigtes Steuerwegeventil keine aufwändige Vorsteuerung benötigt.Advantageously, according to an expedient embodiment of the invention, the control path valve of the side slide by means of an electrical actuating device, such as electromagnets, actuated, directly actuate a spool of the control valves. As a result, the construction cost can be further reduced, since such a directly electrically actuated control valve does not require complex pilot control.

Gemäß einer vorteilhaften Ausgestaltungsform der Erfindung ist die Ladeschaltung des Druckmittelspeichers in einer Speicherladesektion eingebaut und das Steuerwegeventil des Seitenschiebers in die Speicherladesektion eingebaut. Durch den Einbau und die Integration des Steuerwegeventils des Seitenschiebers in die Speicherladesektion des Druckmittelspeichers kann der Bauaufwand weiter verringert werden und es wird erzielt, dass an einem die Steuerwegeventile der restlichen Verbraucher der Arbeitshydraulik enthaltenden Steuerventilblock keine Änderungen für den Einbau des Steuerwegeventils des Seitenschiebers erforderlich sind.According to an advantageous embodiment of the invention, the charging circuit of the accumulator is installed in a storage charging section and the control path valve of the side shifter installed in the accumulator charging section. Through the installation and integration of the control valves of the side shift valve in the accumulator charging section of the accumulator the construction cost can be further reduced and it is achieved that at one the control valves of the remaining consumers the Hydraulic control valve block containing no changes to the installation of the control valves of the side valve are required.

Zweckmäßigerweise ist die Speicherladesektion an einen Steuerventilblock der Arbeitshydraulik angebaut.Conveniently, the accumulator charging section is attached to a control valve block of the working hydraulics.

Beim Seitenschieber, der das Lastaufnahmemittel seitlich verschiebt, ist durch entsprechende Anschläge der Hub begrenzt. Sofern an das Steuerwegeventil des Seitenschiebers ein anderer hydraulischer Verbraucher ohne derartige Anschläge angeschlossen wird, kann der Betriebszustand auftreten, dass bei nicht betätigter Sollwertvorgabeeinrichtung und einem Fehler des Steuerwegeventils, beispielsweise einem in einer Durchflussstellung klemmenden Steuerschieber, die Bewegung des Verbrauchers nicht über den Druckmittelspeicher unterbunden und gestoppt werden kann. Um dies zu verhindern, ist gemäß einer vorteilhaften Weiterbildung der Erfindung vorgesehen, dass zum Anschluss des Seitenschiebers an das Steuerwegeventil Hydraulikanschlüsse vorgesehen sind und die Hydraulikanschlüsse mit einer Codierung versehen sind, die nur einen Anschluss des Seitenschiebers zulassen und einen Anschluss eines anderen Hydraulikverbrauchers verhindern.In the case of the side slide, which laterally shifts the load-carrying attachment, the stroke is limited by corresponding stops. If another hydraulic consumer without such stops is connected to the control path valve of the side shifter, the operating state may occur that, when the setpoint input device is not actuated and the control travel valve malfunctions, for example a control slide clamping in a flow position, the consumer's movement is not inhibited via the pressure medium accumulator and can be stopped. In order to prevent this, according to an advantageous development of the invention, hydraulic connections are provided for connecting the side slide to the control-way valve, and the hydraulic connections are provided with a code which permits only one connection of the side slide and prevents connection of another hydraulic consumer.

Eine derartige Codierung kann gemäß einer vorteilhaften Ausgestaltungsform der Erfindung von Spezialarmaturen gebildet werden. Mit Spezialarmaturen für die Verbraucheranschlüsse des Steuerwegeventils und den Seitenschieber kann auf einfache Weise erzielt werden, dass nur der Seitenschieber an das Steuerwegeventil des Seitenschiebers der erfindungsgemäßen Hydraulikanlage angeschlossen werden kann.Such coding can be formed according to an advantageous embodiment of the invention of special fittings. With special fittings for the consumer connections of the control valves and the side valve can be achieved in a simple manner that only the side shifter can be connected to the control valves of the side valve of the hydraulic system according to the invention.

Gemäß einer vorteilhaften Weiterbildung der Erfindung umfasst die Hydraulikanlage eine hydraulische Lenkungseinrichtung und ist der Druckmittelspeicher zur Versorgung der Lenkungseinrichtung mit Druckmittel vorgesehen. Der Druckmittelspeicher dient somit weiterhin zur Versorgung einer hydraulischen Lenkungseinrichtung der Arbeitsmaschine, wodurch die Energieeffizient der Hydraulikanlage weiter verbessert werden kann.According to an advantageous development of the invention, the hydraulic system comprises a hydraulic steering device and the pressure medium reservoir is provided for supplying the steering device with pressure medium. The accumulator thus continues to serve to supply a hydraulic steering device of the working machine, whereby the energy efficiency of the hydraulic system can be further improved.

Weitere Vorteile und Einzelheiten der Erfindung werden anhand des in den schematischen Figuren dargestellten Ausführungsbeispiels näher erläutert. Hierbei zeigt

Figur 1
einen Hydraulikschaltplan einer erfindungsgemäßen Hydraulikanlage und
Figur 2
einen Ausschnitt der Figur 1 in einer vergrößerten Darstellung.
Further advantages and details of the invention will be explained in more detail with reference to the embodiment shown in the schematic figures. This shows
FIG. 1
a hydraulic circuit diagram of a hydraulic system according to the invention and
FIG. 2
a section of the FIG. 1 in an enlarged view.

In der Figur 1 ist ein Hydraulikschaltplan einer erfindungsgemäßen Hydraulikanlage 1 einer mobilen Arbeitsmaschine, beispielsweise eine als Gegengewichtsgabelstapler ausgebildeten Flurförderzeugs, dargestellt.In the FIG. 1 is a hydraulic circuit diagram of a hydraulic system 1 according to the invention a mobile machine, for example, designed as a counterbalanced forklift truck illustrated.

Die Hydraulikanlage 1 des Flurförderzeugs umfasst eine Arbeitshydraulik 2, eine hydraulische Lenkungseinrichtung 3 und eine hydraulische Bremseinrichtung 4. Die Hydraulikanlage 1 des Flurförderzeugs umfasst weiterhin einen hydrostatischen Fahrantrieb 5 des Flurförderzeugs.The hydraulic system 1 of the industrial truck comprises a working hydraulics 2, a hydraulic steering device 3 and a hydraulic braking device 4. The hydraulic system 1 of the industrial truck further comprises a hydrostatic drive 5 of the industrial truck.

Der hydrostatische Fahrantrieb 5 umfasst eine Fahrpumpe 6, die im geschlossenen Kreislauf an Fahrmotoren 7a, 7b angeschlossen ist, die mit den angetriebenen Rädern 9a, 9b des Flurförderzeugs in trieblicher Verbindung stehen. Die Fahrpumpe 6 ist als im Fördervolumen verstellbare Verstellpumpe ausgebildet, zu deren Verstellung des Fördervolumens eine Stellvorrichtung 10 vorgesehen ist. Der geschlossene Kreislauf des hydrostatischen Fahrantriebs ist weiterhin mit einer Einspeisevorrichtung 11 versehen. Die Stellvorrichtung 10 und die Einspeisevorrichtung 11 stehen zur Versorgung mit Druckmittel mit einer Versorgungsleitung 12 in Verbindung.The hydrostatic drive 5 comprises a drive pump 6, which is connected in a closed circuit to traction motors 7a, 7b which are in operative connection with the driven wheels 9a, 9b of the industrial truck. The drive pump 6 is designed as a variable displacement in the variable displacement pump, to the adjustment of the delivery volume, an adjusting device 10 is provided. The closed circuit of the hydrostatic drive is further provided with a feed device 11. The adjusting device 10 and the feeding device 11 are connected to the supply of pressure medium with a supply line 12 in connection.

Die hydraulische Lenkungseinrichtung 3 umfasst einen hydraulischen Lenkzylinder 15, der mittels eines Lenkventils 16 betätigbar ist. Das Lenkventil 16 ist im dargestellten Ausführungsbeispiel als Lenkorbitrol ausgebildet, das mechanisch betätigbar ist und zur Betätigung mit einem Lenkbetätigungsorgan 17, beispielsweise einem Lenkrad, in mechanischer Wirkverbindung steht. Das Lenkventil 16 steht zur Versorgung mit Druckmittel mit einer Zulaufleitung 18 in Verbindung. Ein Ausgang des Lenkventils 16 ist an eine zu einem Behälter 20 geführte Ablaufleitung 19 angeschlossen.The hydraulic steering device 3 comprises a hydraulic steering cylinder 15 which can be actuated by means of a steering valve 16. The steering valve 16 is formed in the illustrated embodiment as Lenkorbitrol, which is mechanically actuated and is for actuating with a steering actuator 17, such as a steering wheel, in mechanical operative connection. The steering valve 16 is connected to the supply of pressure medium with a supply line 18 in connection. An output of the steering valve 16 is connected to a guided to a container 20 drain line 19.

Die hydraulische Bremseinrichtung 4 weist als Verbraucher eine Bremse 30 auf, beispielsweise eine Federspeicherbremse, die den angetriebenen Rädern 9a, 9b zugeordnet ist und mittels eines Bremsventils 31 betätigbar ist. Das Bremsventil 31 ist im dargestellten Ausführungsbeispiel als mechanisch betätigbares Druckregelventil ausgebildet, das den Bremslüftdruck in einer Bremsleitung 32 steuert, die an einen in Richtung einer Lösestellung wirkenden Druckraum der Federspeicherbremse angeschlossen ist. Das Bremsventil 31 steht zur Betätigung mit einem Bremsbetätigungsorgan 33, beispielsweise einem Bremspedal, in mechanischer Wirkverbindung. Das Bremsventil 31 ist an eine Zulaufleitung 34, an eine zu dem Behälter 20 geführte Ablaufleitung 35 und an die Bremsleitung 32 angeschlossen.The hydraulic braking device 4 has a load 30 as a consumer, for example, a spring brake, which is associated with the driven wheels 9a, 9b and by means of a brake valve 31 is actuated. The brake valve 31 is formed in the illustrated embodiment as a mechanically actuated pressure control valve which controls the brake release pressure in a brake line 32 which is connected to a force acting in the direction of a release position pressure chamber of the spring brake. The brake valve 31 is for actuating with a brake actuator 33, such as a brake pedal, in mechanical operative connection. The brake valve 31 is connected to a supply line 34, to a guided to the container 20 drain line 35 and to the brake pipe 32.

Die Arbeitshydraulik 2 umfasst im dargestellten Ausführungsbeispiel einen Hubantrieb 40, einen Neigeantrieb 41 und einen Seitenschieber 43 als hydraulische Verbraucher. Weiterhin kann die Arbeitshydraulik 2 einen Zusatzverbraucher 42 als weiteren hydraulischen Verbraucher umfassen.The working hydraulics 2 comprises in the illustrated embodiment, a lifting drive 40, a tilt drive 41 and a side gate 43 as hydraulic consumers. Furthermore, the working hydraulics 2 may include an additional consumer 42 as a further hydraulic consumer.

Zur Versorgung des Hubantriebs 40, des Neigeantriebs 41 und des gegebenenfalls vorhandenen Zusatzverbrauchers 42 mit Druckmittel ist eine Arbeitshydraulikpumpe 45 vorgesehen ist, die von einem Antriebsmotor 46 angetrieben ist.To supply the lifting drive 40, the tilt drive 41 and the optionally existing additional consumer 42 with pressure medium, a working hydraulic pump 45 is provided, which is driven by a drive motor 46.

Der Antriebsmotor 46 ist im dargestellten Ausführungsbeispiel als Verbrennungsmotor ausgebildet. Es ist jedoch alternativ möglich, den Antriebsmotor 46 als Elektromotor auszuführen. Der Antriebsmotor 46 treibt weiterhin die Fahrpumpe 6 des hydrostatischen Fahrantriebs 5 an. Der Antriebsmotor 46 dient weiterhin zum Antrieb einer Zusatzpumpe 47, die zur Versorgung der Bremseinrichtung 4, der Verstelleinrichtung 10 der Fahrpumpe 6 und der Einspeisevorrichtung 11 des hydrostatischen Fahrantriebs 5 dient. Die Zusatzpumpe 47 ist im offenen Kreislauf betrieben und saugt Druckmittel über eine Ansaugleitung 48 aus dem Behälter 20 an und fördert das Druckmittel in eine Förderleitung 49, an die die Zulaufleitung 34 der Bremseinrichtung 4 und die Versorgungsleitung 12 der Stellvorrichtung 10 und der Einspeisevorrichtung 11 angeschlossen sind.The drive motor 46 is formed in the illustrated embodiment as an internal combustion engine. However, it is alternatively possible to execute the drive motor 46 as an electric motor. The drive motor 46 continues to drive the drive pump 6 of the hydrostatic drive 5. The drive motor 46 further serves to drive an auxiliary pump 47, which serves to supply the braking device 4, the adjusting device 10 of the drive pump 6 and the feed device 11 of the hydrostatic drive 5. The auxiliary pump 47 is operated in the open circuit and sucks pressure medium via a suction line 48 from the container 20 and promotes the pressure medium in a delivery line 49 to which the supply line 34 of the braking device 4 and the supply line 12 of the adjusting device 10 and the feeding device 11 are connected ,

Die Arbeitshydraulikpumpe 45 ist im offenen Kreislauf betrieben und saugt Druckmittel über eine Ansaugleitung 48 aus dem Behälter 20 an und fördert das Druckmittel in eine Förderleitung 50. Die Förderleitung 50 ist an einen Anschluss P eines Steuerventilblocks 51 der Arbeitshydraulik 2 angeschlossen. Im dargestellten Ausführungsbeispiel ist die Arbeitshydraulikpumpe 45 als im Fördervolumen verstellbare Verstellpumpe ausgebildet, zu deren Verstellung des Fördervolumens eine Stellvorrichtung 45a vorgesehen ist. Zur Versorgung mit Druckmittel ist die Stellvorrichtung 45a mit der Förderleitung 49 der Zusatzpumpe 47 verbunden.The working hydraulic pump 45 is operated in an open circuit and sucks pressure medium via a suction line 48 from the container 20 and conveys the pressure medium in a delivery line 50. The delivery line 50 is connected to a port P of Control valve block 51 of the working hydraulics 2 connected. In the illustrated embodiment, the working hydraulic pump 45 is formed as adjustable in the delivery volume variable displacement pump, to whose adjustment of the delivery volume, an adjusting device 45a is provided. For supply with pressure medium, the adjusting device 45a is connected to the delivery line 49 of the auxiliary pump 47.

Der Steuerventilblock 51 der Arbeitshydraulik 2 enthält ein Steuerwegeventil 52 zur Steuerung des Hubantriebs 40, ein Steuerwegeventil 53 zur Steuerung des Neigeantriebs 41 und ein Steuerwegeventil 54 zur Steuerung des gegebenenfalls vorhandenen Zusatzverbrauchers 42.The control valve block 51 of the working hydraulics 2 includes a control-way valve 52 for controlling the lifting drive 40, a control-way valve 53 for controlling the tilting drive 41, and a control-way valve 54 for controlling the optional additional consumer 42.

Der Anschluss P ist in dem Steuerventilblock 51 - wie in der Figur 2 näher ersichtlich ist - mit einer Zulaufleitung 60 verbindbar, an die mittels entsprechender Förderzweigleitungen die Steuerwegeventile 52, 53, 54 angeschlossen sind. Ein Anschluss T des Steuerventilblocks 51, an den eine zu dem Behälter 20 geführte Tankleitung 61 angeschlossen ist, steht in dem Steuerventilblock 51 mit einer Behälterleitung 62 in Verbindung, an die mittels Behälterzweigleitungen die Steuerwegeventil 52, 53, 54 angeschlossen sind. Die Steuerwegeventil 52, 53, 54 sind als Load-Sensing-Wegeventile ausgebildet, wobei bei einer Ansteuerung der Steuerwegeventile 52, 53, 54 und somit einer Betätigung der Verbrauchers 40, 41, 42 der höchste Lastdruck in eine Lastdruckmeldeleitung 63 der Arbeitshydraulik 2 gemeldet wird.The port P is in the control valve block 51 - as in FIG. 2 can be seen - connected to a supply line 60, to which by means of appropriate Förderzweigleitungen the control valves 52, 53, 54 are connected. A port T of the control valve block 51, to which a tank line 61 led to the tank 20 is connected, communicates in the control valve block 51 with a tank line 62 to which the control directional valves 52, 53, 54 are connected by means of tank branch lines. The control travel valve 52, 53, 54 are designed as load-sensing directional control valves, wherein upon activation of the control travel valves 52, 53, 54 and thus an actuation of the consumer 40, 41, 42, the highest load pressure is reported in a load pressure reporting line 63 of the working hydraulics 2 ,

Die Steuerwegeventile 52, 53, 54 sind als vorgesteuerte Steuerwegeventile ausgebildet und jeweils elektro-hydraulisch betätigbar. Hierzu sind zur Betätigung des Steuerwegeventils 52 elektrisch betätigbare Vorsteuerventile 52a, 52b, zur Betätigung des Steuerwegeventils 53 elektrisch betätigbare Vorsteuerventile 53a, 53b und zur Betätigung des Steuerwegeventils 54 elektrisch betätigbare Vorsteuerventile 54a, 54b vorgesehen. Die Vorsteuerventile 52a, 52b, 53a, 53b, 54a, 54b sind beispielsweise als mittels eines Proportionalmagneten betätigbare Druckminderventile ausgebildet. Die Vorsteuerventile 52a, 52b, 53a, 53b, 54a, 54b stehen eingangsseitig zur Versorgung mit einem Steuerdruck mit einer Steuerdruckleitung 68 des Steuerventilblocks 51 in Verbindung, die an einen Anschluss Z der Steuerventilblocks 51 geführt ist. Über eine an den Anschluss Z angeschlossene Versorgungsleitung 69 steht die Steuerdruckleitung 68 mit der Förderleitung 49 der Zusatzpumpe 47 in Verbindung. Bei einer elektrischen Ansteuerung und somit einer Betätigung erzeugen die Vorsteuerventile 52a, 52b, 53a, 53b, 54a, 54b aus dem in der Steuerdruckleitung 68 anstehenden Steuerdruck einen Betätigungsdruck, der das entsprechende Steuerwegeventil 52, 53, 54 in eine entsprechende Steuerstellung zur Betätigung des Verbrauchers 40, 41, 42 beaufschlagt.The control valves 52, 53, 54 are designed as pilot-operated control valves and each electro-hydraulically actuated. To this end, electrically actuatable pilot valves 52a, 52b are provided for actuating the control travel valve 52, electrically actuatable pilot valves 53a, 53b are provided for actuating the control travel valve 53, and electrically actuatable pilot valves 54a, 54b are provided for actuating the control travel valve 54. The pilot valves 52a, 52b, 53a, 53b, 54a, 54b are designed, for example, as pressure-reducing valves which can be actuated by means of a proportional magnet. The pilot valves 52a, 52b, 53a, 53b, 54a, 54b are on the input side to supply with a control pressure with a control pressure line 68 of the control valve block 51 in connection, which is guided to a port Z of the control valve block 51. Via a supply line 69 connected to the connection Z, the control pressure line 68 communicates with the delivery line 49 of the auxiliary pump 47. at an electric control and thus an operation to generate the pilot valves 52a, 52b, 53a, 53b, 54a, 54b from the pending in the control pressure line 68 control pressure an actuating pressure, the corresponding control way valve 52, 53, 54 in a corresponding control position for actuating the consumer 40th , 41, 42 charged.

Die Lastdruckmeldeleitung 63 ist an eine Förderstromregeleinrichtung 70 des Steuerventilblocks 51 geführt. Die Förderstromregeleinrichtung 70 ist als Eingangsdruckwaage ausgebildet, die in einer die Zulaufleitung 60 mit der Behälterleitung 62 verbindenden Verbindungsleitung 71 angeordnet ist. Die Eingangsdruckwaage ist hierbei in Richtung einer Sperrstellung von dem in der Lastdruckmeldeleitung 63 anstehenden Lastdruck der Verbraucher 40, 41, 42 und einer Feder 72 beaufschlagbar. In Richtung einer Durchflussstellung ist die Eingangsdruckwaage von dem in der Zulaufleitung 60 anstehenden Förderdruck beaufschlagbar.The load pressure detection line 63 is guided to a flow control device 70 of the control valve block 51. The flow control device 70 is designed as an inlet pressure balance, which is arranged in a connecting line 71 connecting the feed line 60 with the tank line 62. The inlet pressure compensator is in this case acted upon in the direction of a blocking position by the load pressure of the consumers 40, 41, 42 present in the load pressure signaling line 63 and a spring 72. In the direction of a flow position, the inlet pressure compensator can be acted upon by the delivery pressure present in the feed line 60.

Der Steuerventilblock 51 weist zur Freigabe der Steuerwegeventile 52, 53, 54 und der entsprechenden Bewegungen der Verbraucher 40, 41, 42 ein Freigabeventil 73 auf. Das Freigabeventil 73 steuert die Steuerdruckleitung 68 und die Lastdruckmeldeleitung 63 an und ist elektrisch betätigbar.The control valve block 51 has a release valve 73 for releasing the control travel valves 52, 53, 54 and the corresponding movements of the consumers 40, 41, 42. The release valve 73 controls the control pressure line 68 and the load pressure detection line 63 and is electrically actuated.

Erfindungsgemäß umfasst die Hydraulikanlage 1 einen Druckmittelspeicher 80, der zur Versorgung des Seitenschiebers 43 mit Druckmittel dient und der zum Laden mit Druckmittel mit der Arbeitshydraulikpumpe 45 der Arbeitshydraulik 2 verbindbar ist.According to the invention, the hydraulic system 1 comprises a pressure medium reservoir 80, which serves to supply the side slide 43 with pressure medium and which can be connected to the working hydraulic pump 2 for charging with pressure medium to the working hydraulic pump.

Zum Laden des Druckmittelspeichers 50 ist eine Ladeschaltung 81 vorgesehen. Die Ladeschaltung 81 ist in einer Speicherladesektion 82 eingebaut, die an den Steuerventilblock 51 der Arbeitshydraulik 2 angebaut ist.For loading the accumulator 50, a charging circuit 81 is provided. The charging circuit 81 is installed in a accumulator charging section 82 which is attached to the control valve block 51 of the working hydraulic system 2.

Die Ladeschaltung 81 weist ein Vorspannventil 84 auf, das die bevorzugte Versorgung des Druckmittelspeichers 80 mit Druckmittel der Arbeitshydraulikpumpe 45 sicherstellt. Das Vorspannventil 84 steht eingangsseitig mit der Förderleitung 50 der Arbeitshydraulikpumpe 45 in Verbindung. Das Vorspannventil 84 ist ausgangsseitig an die zu den Steuerwegeventilen 52, 53, 54 der Arbeitshydraulik 2 geführten Zulaufleitung 60 sowie an eine zu dem Druckmittelspeicher 80 geführte Ladeleitung 83 angeschlossen.The charging circuit 81 has a biasing valve 84, which ensures the preferred supply of the accumulator 80 with pressure medium of the working hydraulic pump 45. The biasing valve 84 is the input side to the delivery line 50 of the working hydraulic pump 45 in connection. The biasing valve 84 is the output side to the guided to the control directional valves 52, 53, 54 of the working hydraulics 2 Inlet line 60 and connected to a guided to the accumulator 80 charge line 83.

In der Ladeleitung 83 ist ein Ladeventil 85 der Ladeschaltung 81 angeordnet, mittels dem der Ladebetrieb des Druckmittelspeichers 80 steuerbar ist. Das Ladeventil 85 ist im dargestellten Ausführungsbeispiel als elektrisch ansteuerbares Druckminderventil ausgebildet. Das Druckminderventil steht an einem Anschluss mit dem zu dem Vorspannventil 84 geführten Abschnitt der Ladeleitung 83 in Verbindung und an einem weiteren Anschluss mit dem zu dem Druckmittelspeicher 80 geführten Abschnitt der Ladeleitung 83. Ein weiterer Anschluss des Druckminderventils ist mit der Behälterleitung 62 verbunden.In the charging line 83, a charging valve 85 of the charging circuit 81 is arranged, by means of which the loading operation of the pressure medium accumulator 80 is controllable. The charging valve 85 is formed in the illustrated embodiment as an electrically controllable pressure reducing valve. The pressure reducing valve is connected at one connection to the section of the charge line 83 guided to the pretensioning valve 84 and at another connection to the section of the charge line 83 leading to the pressure medium reservoir 80. A further connection of the pressure reducing valve is connected to the container line 62.

Das Ladeventil 85 steht zur Ansteuerung mit einer elektronischen Steuereinrichtung 90 in Wirkverbindung.The charging valve 85 is connected to the control with an electronic control device 90 in operative connection.

Zur Erfassung des in dem Druckmittelspeicher 80 vorhandenen Druckes ist ein Drucksensor 91 vorgesehen, der mit der elektronischen Steuereinrichtung 90 in Verbindung steht.For detecting the pressure present in the pressure medium accumulator 80, a pressure sensor 91 is provided, which communicates with the electronic control device 90.

In der Ladeleitung 83 ist stromab des Ladeventils 85 ein in Richtung zum Druckmittelspeicher 80 öffnenden Sperrventil 89 angeordnet. Das Sperrventil 89 ist im dargestellten Ausführungsbeispiel als Rückschlagventil, beispielsweise federvorgespanntes Rückschlagventil, ausgebildet.In the charge line 83 downstream of the charging valve 85 in the direction of the pressure medium accumulator 80 opening check valve 89 is arranged. The check valve 89 is formed in the illustrated embodiment as a check valve, such as spring-biased check valve.

Der Seitenschieber 43 ist mittels eines Steuerwegeventils 100 steuerbar, das zur Versorgung mit Druckmittel an den Druckmittelspeicher 80 angeschlossen ist. Das Steuerwegeventil 100 des Seitenschiebers 43 ist zur Versorgung mit Druckmittel aus dem Druckmittelspeicher 80 mittels einer Zulaufleitung 101 an die Ladeleitung 83 zwischen dem Druckmittelspeicher 80 und dem Sperrventil 89 angeschlossen. Weitere Anschlüsse des Steuerwegeventils 100 stehen mittels einer Ablaufleitung 102 mit der Behälterleitung 62 des Steuerventilblocks 51 in Verbindung.The side shifter 43 is controllable by means of a control valve 100 which is connected to the pressure medium accumulator 80 for supply with pressure medium. The control valve 100 of the side valve 43 is connected to the supply of pressure medium from the accumulator 80 by means of a supply line 101 to the charging line 83 between the accumulator 80 and the check valve 89. Further connections of the control-way valve 100 are connected by means of a drain line 102 to the tank line 62 of the control valve block 51.

Der Seitenschieber 43 ist als doppelt-wirkender Verbraucher ausgebildet, zu dessen Anschluss an das Steuerwegeventil 100 Hydraulikanschlüsse A4, B4 vorgesehen sind.The side shifter 43 is designed as a double-acting consumer, to whose connection to the control-way valve 100 hydraulic connections A4, B4 are provided.

Das Steuerwegeventil 100 ist als Längsschieberventil mit einem Steuerschieber ausgebildet. Das Steuerwegeventil 100 weist eine als Mittelstellung ausgebildete Neutralstellung 100a auf, in der die Zulaufleitung 101, die Ablaufleitung 102 und die Hydraulikanschlüsse A4, B4 abgesperrt sind. In einer ersten Steuerstellung 100b ist die Zulaufleitung 101 mit dem Hydraulikanschluss A4 und die Ablaufleitung 102 mit dem Hydraulikanschluss B4 verbunden. In einer zweiten Steuerstellung 100c ist die Zulaufleitung 101 mit dem Hydraulikanschluss B4 und die Ablaufleitung 102 mit dem Hydraulikanschluss A4 verbunden. Das Steuerwegeventil 100 ist als in Zwischenstellungen drosselndes Proportionalventil ausgebildet.The control-way valve 100 is designed as a longitudinal slide valve with a spool. The control-way valve 100 has a neutral position 100a in the form of a middle position, in which the supply line 101, the discharge line 102 and the hydraulic connections A4, B4 are shut off. In a first control position 100b, the supply line 101 is connected to the hydraulic connection A4 and the discharge line 102 is connected to the hydraulic connection B4. In a second control position 100c, the supply line 101 is connected to the hydraulic port B4 and the drain line 102 to the hydraulic port A4. The control-way valve 100 is designed as a proportional valve throttling in intermediate positions.

Die Hydraulikanschlüsse A4, B4 umfassen bei der Erfindung eine Codierung, beispielsweise mittels Spezialarmaturen, die nur den Anschluss des Seitenschiebers 43 an das Steuerwegeventil 100 zulässt.The hydraulic connections A4, B4 in the invention include a coding, for example by means of special fittings, which allows only the connection of the side shifter 43 to the control-way valve 100.

Das Steuerwegeventil 100 des Seitenschiebers 43 ist elektrisch betätigbar. Das Steuerwegeventil 100 des Seitenschiebers 43 steht zur Ansteuerung mit der elektronischen Steuereinrichtung 90 in Verbindung. Die Steuereinrichtung 90 steht eingangsseitig mit einer Sollwertvorgabeeinrichtung 105 für den Seitenschieber, beispielsweise einem Joystick, in Wirkverbindung.The control-way valve 100 of the side shifter 43 is electrically operated. The control-way valve 100 of the side-shifter 43 is connected to the electronic control device 90 for activation. The control device 90 is on the input side with a setpoint input device 105 for the side shifter, such as a joystick in operative connection.

Mit der Sollwertvorgabeeinrichtung 105 kann in einer zweiten Bewegungsrichtung der Zusatzverbraucher 42 gesteuert werden. Zur Steuerung des Hubantriebs 40 und des Neigeantriebs 41 steht mit der elektronischen Steuereinrichtung 90 eine weitere Sollwertvorgabeeinrichtung 106, beispielsweise ein Joystick, in Verbindung.With the desired value setting device 105, the additional consumer 42 can be controlled in a second direction of movement. To control the lifting drive 40 and the tilt drive 41 is connected to the electronic control device 90, another setpoint input device 106, such as a joystick in combination.

Das Steuerwegeventil 100 des Seitenschiebers 43 ist mittels Federn in die Neutralstellung 100a beaufschlagt. Zur Betätigung des Steuerwegeventils 100 in Richtung der Steuerstellungen 100b, 100c sind im dargestellten Ausführungsbeispiel zwei Elektromagnete 104a, 104b als elektrische Betätigungseinrichtung vorgesehen, die direkt den Steuerschieber des Steuerwegeventils 100 betätigen und auslenken.The control travel valve 100 of the side slider 43 is acted upon by springs in the neutral position 100a. For actuation of the control travel valve 100 in the direction of the control positions 100b, 100c, two electromagnets 104a, 104b are provided in the illustrated embodiment as an electrical actuating device, which actuate and deflect the spool of the control travel valve 100 directly.

Das Steuerwegeventil 100 des Seitenschiebers 43 ist zusammen mit den Ventilen der Ladeschaltung 81 des Druckmittelspeichers 80 in der Speicherladesektion 82 angeordnet und eingebaut.The control-way valve 100 of the side shifter 43 is disposed and installed in the accumulator charging section 82 together with the valves of the charging circuit 81 of the accumulator 80.

Im dargestellten Ausführungsbeispiel dient der Druckmittelspeicher 80 weiterhin zur Versorgung der hydraulischen Lenkungseinrichtung 3 mit Druckmittel. Zur Versorgung der Lenkungseinrichtung 3 mit Druckmittel aus dem Druckmittelspeicher 80 ist die Zulaufleitung 18 der Lenkungseinrichtung 3 an die Ladeleitung 83 zwischen dem Sperrventil 89 und dem Druckmittelspeicher 80 angeschlossen.In the illustrated embodiment, the pressure fluid accumulator 80 continues to supply the hydraulic steering device 3 with pressure medium. To supply the steering device 3 with pressure medium from the accumulator 80, the supply line 18 of the steering device 3 is connected to the charging line 83 between the check valve 89 and the accumulator 80.

Die erfindungsgemäße Versorgung des Seitenschiebers 43 mit Druckmittel aus dem Druckmittelspeicher 80 der Hydraulikanlage 1 weist eine Reihe von Vorteilen auf.The supply according to the invention of the side slide 43 with pressure medium from the pressure medium reservoir 80 of the hydraulic system 1 has a number of advantages.

Das Steuerwegeventil 100 des Seitenschiebers 43 kann an den Durchflussmengenbedarf des Seitenschiebers 43 angepasst und abgestimmt werden, wodurch sich eine gute Dosierbarkeit der Bewegungen des Seitenschiebers 43 durch Auslenkung der Sollwertvorgabeeinrichtung 105 erzielen lässt. Da der Seitenschieber 43 nur einen geringen Volumenstrombedarf aufweist, ergibt sich ein klein und kompakt bauendes Steuerwegeventil 100, das im Vergleich zu Hydraulikanlagen des Standes der Technik eine Verringerung des Bauraums des Steuerventilblocks 51 ermöglicht.The control-way valve 100 of the side-shifter 43 can be adapted and adjusted to the flow-rate requirement of the side-shifter 43, whereby a good metering of the movements of the side-shifter 43 can be achieved by deflection of the setpoint-setting device 105. Since the side slider 43 has only a small volume flow requirement, results in a small and compact design control travel valve 100, which allows a reduction in the space of the control valve block 51 compared to hydraulic systems of the prior art.

Der Seitenschieber 43 kann bei einer Ansteuerung des Steuerwegeventils 100 bedarfsgerecht mit der benötigten Druckmittelmenge aus dem Druckmittelspeicher 80 versorgt werden. Ein Abdrosseln von überschüssig geförderten Volumenstroms der Arbeitshydraulikpumpe 45 an der Eingangsdruckwaage 70 wird verhindert, wodurch sich Vorteile hinsichtlich der Energieeffizienz ergeben. Zudem wird der Wärmeeintrag in das Druckmittel der Hydraulikanlage 1 verringert, wodurch der Kühlbedarf sinkt.The side shifter 43 can be supplied with the required quantity of pressure medium from the accumulator 80 when the control travel valve 100 is activated. Restricting excess flow rate of the working hydraulic pump 45 to the input pressure compensator 70 is prevented, which results in advantages in terms of energy efficiency. In addition, the heat input is reduced in the pressure medium of the hydraulic system 1, whereby the cooling demand decreases.

Der Seitenschieber 43 kann parallel und unabhängig zu einem Ladevorgang des Druckmittelspeichers 80 durch die Arbeitshydraulikpumpe 45 betrieben werden.The side shifter 43 can be operated in parallel and independently to a charging operation of the accumulator 80 by the working hydraulic pump 45.

Durch die direkte elektrische Betätigung des Steuerwegeventils 100 und dem Entfall von Vorsteuerventilen ergibt sich ein verringerter Bauaufwand.The direct electrical actuation of the control valve 100 and the elimination of pilot valves results in a reduced construction cost.

Der Einbau des Steuerwegeventils 100 des Seitenschiebers 43 in die Speicherladesektion 82 bietet Vorteile bei der Ausführung des Steuerventilblocks 51 der Arbeitshydraulik 2, da der Steuerventilblock 51 bei Varianten von Flurförderzeugen mit oder ohne Seitenschieber 43 unverändert bleibt.The installation of the control path valve 100 of the side gate 43 in the accumulator charging section 82 offers advantages in the design of the control valve block 51 of the working hydraulics 2, since the control valve block 51 remains unchanged in variants of trucks with or without sideshift 43.

Claims (9)

  1. Hydraulic system (1) for a mobile work machine, in particular an industrial truck, with working hydraulics (2) comprising a lifting drive (40) and a side loader (43), wherein the hydraulic system (1) has a working hydraulics pump (45) which is provided for supplying the lifting drive (40) with pressure medium, wherein the hydraulic system (1) comprises a pressure medium reservoir (80), characterized in that the pressure medium reservoir (80) can be charged up with pressure medium from the working hydraulics pump (45) by means of a charging circuit (81), wherein the charging circuit (81) has a pretensioning valve (84) which ensures the preferred supply of the pressure medium reservoir (80) with pressure medium of the working hydraulics pump (45), wherein the pretensioning valve (84) is connected on the input side to a conveying line (50) of the working hydraulics pump (45), and the pretensioning valve (84) is connected on the output side to a feed line (60), which is guided to directional control valves (52, 53, 54) of the working hydraulics (2), and to a charging line (83) guided to the pressure medium reservoir (80), wherein the side loader (43) is connected to the pressure medium reservoir (80) for supplying with pressure medium.
  2. Hydraulic system according to Claim 1, characterized in that the side loader (43) is controllable by means of a directional control valve (100) which is connected to the pressure medium reservoir (80) for supplying with pressure medium.
  3. Hydraulic system according to Claim 2, characterized in that the charging circuit (81) of the pressure medium reservoir comprises the charging line (83) which, for charging the pressure medium reservoir (80), is connectable to the conveying line (50) of the working hydraulics pump (45), wherein a shut-off valve (89), in particular a nonreturn valve opening in the direction of the pressure medium reservoir (80), is arranged in the charging line (83), wherein the directional control valve (100) of the side loader (43) is connected to the charging line (83) between the pressure medium reservoir (80) and the shut-off valve (89) for supplying with pressure medium from the pressure medium reservoir (80) .
  4. Hydraulic system according to Claim 2 or 3, characterized in that the directional control valve (100) of the side loader (43) is electrically actuable, wherein, in order to activate the directional control valve (100) of the side loader (43), an electronic control device (90) is provided which is operatively connected on the input side to a desired-value-specifying device (105) for the side loader (43), for example a joystick.
  5. Hydraulic system according to one of Claims 2 to 4, characterized in that the directional control valve (100) of the side loader (43) is actuable by means of an electrical actuating device, for example electromagnets (104a; 104b) which directly actuate a control slide of the directional control valve (100).
  6. Hydraulic system according to one of Claims 2 to 5, characterized in that the charging circuit (81) of the pressure medium reservoir (80) is installed in a reservoir-charging section (82), and the directional control valve (100) of the side loader (43) is installed in the reservoir-charging section (82) .
  7. Hydraulic system according to Claim 6, characterized in that the reservoir-charging section (82) is fitted onto a control valve block (51) of the working hydraulics (2).
  8. Hydraulic system according to one of Claims 2 to 7, characterized in that hydraulic connections (A4, B4) are provided for connecting the side loader (43) to the directional control valve (100), wherein the hydraulic connections (A4, B4) are provided with a coding permitting only a connection of the side loader (43) and preventing a connection of a different hydraulic consumer.
  9. Hydraulic system according to one of Claims 1 to 8, characterized in that the hydraulic system (1) comprises a hydraulic steering device (3), and the pressure medium reservoir (80) is provided for supplying the steering device (3) with pressure medium.
EP15179000.3A 2014-08-01 2015-07-30 Hydraulic system of a mobile work machine, in particular an industrial fork-lift truck Not-in-force EP2980006B1 (en)

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EP2980006B1 true EP2980006B1 (en) 2018-11-21

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Family Cites Families (5)

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Publication number Priority date Publication date Assignee Title
DE2741496A1 (en) * 1977-09-15 1979-03-29 Jungheinrich Kg FLOOR CONVEYOR VEHICLE WITH A HYDRAULIC LIFTING CYLINDER PISTON DEVICE FOR A LIFTING FRAME
DE19903174C2 (en) * 1999-01-27 2001-05-31 Kaup Gmbh & Co Kg Attachment for industrial trucks, with a mast, especially for forklifts
DE10224730B4 (en) 2001-06-29 2012-09-27 Linde Material Handling Gmbh Hydraulic control device
US20110041919A1 (en) * 2009-08-21 2011-02-24 Turner Mark E System of identification fittings for hydraulic pressure lines
US9453503B2 (en) * 2012-01-09 2016-09-27 Eaton Corporation Method for obtaining a full range of lift speeds using a single input

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