EP1369598B1 - Electro-hydraulic lifting control device for industrial use vehicles - Google Patents

Electro-hydraulic lifting control device for industrial use vehicles Download PDF

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Publication number
EP1369598B1
EP1369598B1 EP20030002659 EP03002659A EP1369598B1 EP 1369598 B1 EP1369598 B1 EP 1369598B1 EP 20030002659 EP20030002659 EP 20030002659 EP 03002659 A EP03002659 A EP 03002659A EP 1369598 B1 EP1369598 B1 EP 1369598B1
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EP
European Patent Office
Prior art keywords
pressure
pilot
valve
flow regulator
control device
Prior art date
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Expired - Fee Related
Application number
EP20030002659
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German (de)
French (fr)
Other versions
EP1369598B2 (en
EP1369598A1 (en
Inventor
Martin Dipl.-Ing. Univ. Heusser
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Hawe Hydraulik GmbH and Co KG
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Hawe Hydraulik GmbH and Co KG
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • F15B20/008—Valve failure
    • 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
    • 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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/003—Systems with load-holding valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20538—Type of pump constant capacity
    • 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
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40576—Assemblies of multiple valves
    • 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
    • F15B2211/40—Flow control
    • F15B2211/41—Flow control characterised by the positions of the valve element
    • F15B2211/413—Flow control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional valves
    • 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
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/4159—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source, an output member and a return line
    • 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/426—Flow control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/40—Flow control
    • F15B2211/465—Flow control with pressure compensation
    • 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
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50563—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure
    • F15B2211/50581—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using counterbalance valves
    • F15B2211/5059—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using counterbalance valves using double counterbalance valves

Definitions

  • the invention relates to an electro-hydraulic stroke control device specified in the preamble of claim 1 Art.
  • a known electrically controllable lifting module (Fig. 1) is the three-way flow regulator in the Senkzweig downstream connected to the tank and for energy recovery with the suction side of the pump.
  • the lifting strand since the speed of the hydraulic cylinder is controlled by the speed of the pump, only one black / white 2/2 solenoid valve is provided. From the lifting strand branches off a drain line with a 2/2-way solenoid valve to the tank, which is electrically connected to the passageway during sinking, if no additional consumer is to be supplied. If the three-way current regulator gets stuck in lowering mode as a result of pollution, the lifting cylinder will stop moving in an uncontrolled manner.
  • EP 0 546 300 A EP 0 893 607 A . US 5,701,618 A ,
  • the invention has for its object to provide an electro-hydraulic stroke control device of this type, the reliability is increased against disturbances due to contamination of the hydraulic medium or developing mechanical damage hydraulic switching elements with minimal effort.
  • an additional activatable braking function or intentional active disconnection of one or both current regulator is desirable, or should adjust the supply pressure for at least one other hydraulic consumer in a simple manner with minimal effort leave as eg for lifting control.
  • the mentioned effort relates mainly to magnets as a valve actuator.
  • the reliability of the electro-hydraulic Hub horrettivorides is increased because the redundancy switching element then actively engages when at least one other electrically actuated switching element should not work properly. Due to the active engagement of the redundancy switching element, in particular uncontrolled load movements or unintentional lowering of the load are avoided.
  • the proportional pressure control valve remains stuck in the lowering control or the lifting control, so that it can no longer be adjusted by its proportional magnet (the lifting hydraulic cylinder would then either move under the load or extend against the load), then the effective redundancy switching element is brought in the open position either the pressure compensator of the two-way flow regulator in the load-holding shut-off position (stopping the sinking Hubhydraulikzylinders) or the pressure compensator of the three-way flow regulator in the open position (deriving the flow to the tank, so that the hydraulic cylinder stops).
  • the redundancy switching element With proper function of the Proportionaldruckregelventiis the redundancy switching element has no influence in the respective pilot circuit, since it is energized with energization of the respective proportional solenoid and holds its closed position.
  • the redundancy switching element is an easy-to-integrate safety component and requires only minimal effort. For this function, only the magnet of the switching element and hydraulically a simple, small-sized valve for the pilot oil is required for the control electronics.
  • the redundancy switching element offers further advantageous possibilities, whereby it must be assumed that the electronic control provided in modern industrial trucks contains a microprocessor which offers many possibilities for individual program routines or functions.
  • the redundancy switching element By adjusting the redundancy switching element in the open position during the lowering control, for example, the lowering movement can be additionally braked individually by the pressure compensator of the two-way flow regulator is brought in another way in the closed position, as by the pressure difference of the proportional pressure control valve. A similar individual braking could also be done in the lift control via the pressure compensator of the three-way current controller.
  • the redundancy switching element can actively activate the two-way current regulator or the three-way current regulator, ie the respective pressure compensator into the closed position or full open position bring.
  • the redundancy switching element as a variable pressure limiting valve change the pilot pressure of the pressure compensator of the three-way flow regulator, which adjusts the supply pressure for at least one further hydraulic consumer, which is lower than that of the lifting hydraulic cylinder. It opens up the redundancy switching element in conjunction with the control electronics possibilities for a more universal control of the industrial truck, the inherent performance of the parent electronics is used without additional effort.
  • the redundancy switch should be located between the tank and either the opening pilot side of the pressure balance of the two-way flow regulator and / or the closing pilot side of the pressure balance of the three-way flow regulator. In this position, the redundancy switching element relieved when actuated, the pilot pressure for the respective pressure compensator, so that it forcibly goes into its closed position or passage position.
  • redundancy switching element In order to be able to set a sensitive control of the pressure relief by the redundancy switching element, it is expedient to interpret this as a 2/2-way control valve with pressure precontrol in the opening direction and a proportional solenoid as an actuator for adjusting in the closing direction.
  • This design is advantageous if the redundancy switching element as a variable pressure relief valve has to adjust the pilot pressure individually. However, for the desired safety aspect, it is sufficient to be able to change the redundancy switching element only between an open and a closed position (black / white function).
  • a 2/2-way valve with pressure pre-control in the opening direction and a black / white magnet as an actuator for adjustment in the closing direction is sufficient only for increased safety requirements as a redundancy switching element.
  • a 2/2-way valve of this type is inexpensive and reliable.
  • the redundancy switching element is here a seat valve, which is characterized by a leak-free closed position.
  • pilot pressure is applied to the respective pressure compensator, the redundancy switching element is thereby acted upon in the direction of its open position, which, however, it is only able to take if it is not actively adjusted electrically in its closed position.
  • the redundancy switching element is assigned to both current regulators and fulfills its function for the respective current regulator as a function of the pressure. That is, the shuttle valve connects each of the working pressure compensator with the redundancy switch member, in which case the selected pilot pressure or the higher pilot pressure is applied.
  • the redundancy switching element thus operates automatically in the lift control with the three-way current controller, while in the lowering control with the two-way current controller together.
  • the redundancy switching element can be arranged parallel to a control pressure-relief valve. This offers structural advantages, because in any case a pilot pressure duct runs via the pressure limiting valve to the tank or to the return line. If the redundancy switching element is designed as a pressure control valve which can be actuated by a proportional magnet and which assumes the function of a pressure-limiting valve with varying energization, the pressure-limiting valve can optionally be omitted.
  • the redundancy switching element performed by the control electronics and, as mentioned, when configured as a proportional pressure control valve, perform the function of an electrically adjustable pressure relief valve, so that the pressure compensator of the three-way flow control adjusts a lower supply pressure for other hydraulic consumers. All the aforementioned functions can be achieved with a small valve and a magnet.
  • the redundancy switching element in case of failure, for example, the three-way current regulator in the lowering control in its open position goes, as soon as the proportional solenoid of the three-way current regulator is de-energized, the stroke hydraulic cylinder could give way very slowly over the pilot circuit despite the load-holding function of the pressure compensator.
  • the redundancy switching element it is expedient to form the redundancy switching element as a 4/2-way switching valve with a solenoid as the actuator and shut off the pilot line to Senkzweig at least stacker-tight, while the opening pilot side of the pressure compensator is relieved directly to the tank. This results in a perfect load-holding function of the pressure balance, so that the lifting hydraulic cylinder remains reliably stopped even when stuck proportional-pressure relief valve.
  • the redundancy switching element In order to ensure this high safety standard even if the redundancy switching element is to perform the function of reducing the pressure for other consumers, it is expedient to form the redundancy switching element even as a 4/3-way proportional pressure control valve with a proportional solenoid as the actuator and the separate two pilot control lines from Senkzweig and from the closing pilot side of the pressure compensator of the two-way current controller separately. If the 4/3-way proportional pressure control valve de-energized when canceling the lowering control, then it assumes its shutdown, in which relieves the opening pilot side of the pressure compensator of the two-way flow controller to the tank and the pressure compensator is set to load. This shift position is also assumed when the lift control is canceled.
  • the closing pilot side of the pressure compensator of the three-way flow regulator is relieved to the tank, so that the pressure compensator, if supply pressure is present, is set in the closed position.
  • the proportional solenoid of the 4/3-way proportional pressure control valve is also fully energized. The switching position generated thereby sets the pilot line from the Senkzweig to the opening pilot side of the pressure compensator of the two-way flow regulator on passage and interrupts the connection of the pilot line to the closing pilot side of the pressure compensator of the three-way flow regulator to the tank.
  • the proportional solenoid of the 4/3-way proportional pressure control valve is subjected to a current value in accordance with the desired pressure reduction against the control spring and the pilot pressure a control function for reducing the pilot pressure for the pressure compensator of the three-way current controller is executed. All these functions are achieved with a single valve and a single proportional solenoid.
  • the 4/2-way switching valve or the 4/3-way proportional pressure control valve is designed as a slide valve in stapler-tight design. This means that the valve fulfills the requirement valid for the stacker leak criterion.
  • the redundancy switching element To get along with the smallest possible and weak and therefore cost-effective solenoids or proportional magnets for the redundancy switching element, it is expedient to provide a pressure-balanced with respect to the tank pressure valve slide in the slide valve. If the redundancy switching element also controls the pressure limit for the other consumers, it is particularly expedient to let the pilot pressure, against which the proportional solenoid operates, act only on a small partial area of the valve slide.
  • the electro-hydraulic stroke control device is usable with this design both for lift trucks with an internal combustion engine and an electric motor.
  • the Hublichvorraum can be used without or with energy recovery (Nutzsenken).
  • Nutzsenken For payload operation in which the electric motor is operated as a generator via the pump, it is only necessary to connect the Senkzweig upstream of the pressure compensator of the two-way flow regulator via a Nutztechnisch with the suction side of the pump, and to arrange a check valve between the pump and the tank , At high load pressure and without additional connected hydraulic consumers, the full amount (controlled by the pressure compensator of the two-way flow regulator) can be pumped through the pump.
  • the pressure compensator of the two-way current regulator regulates a current through the pump when it is being used, which corresponds to the current demand.
  • the redundancy switching element does not intervene in case of proper function, but only in the case of a fault, and occasionally in the pressure reduction for the other consumers.
  • the electrically operable components of the stroke control device should be connected to an electronic controller including a microprocessor or logic circuit which executes the different operating routines as needed, as selected, or according to an automated scheme.
  • a hydraulic cylinder Z for lifting control from a pressure source P (hydraulic pump) is supplied, which is driven for example by electric motor or diesel engine M and, if no further hydraulic consumers are to be supplied, in the lowering control of the hydraulic cylinder Z are can, or (Fig. 4) then runs for energy recovery as a motor.
  • the hydraulic pump sucks from a tank T and acts on a lifting strand 1, in which a three-way flow regulator R1 is provided.
  • the three-way flow regulator R1 consists of a proportional pressure control valve 3, with which the lifting speed is set by a proportional solenoid 4, and a pressure compensator 5 between the lifting strand 1 and the tank T.
  • the pressure control valve 3 is acted upon by spring loading in the direction of the shut-off position. Between the hydraulic cylinder Z and the pressure control valve 3, a pilot control line 6 branches off to the closing pilot side (at which a control spring also acts) of the pressure compensator 5. From the lifting strand 1 branches off upstream of the pressure control valve 3, a further pilot line 7 to the opening pilot side of the pressure compensator 5 from.
  • the two-way flow regulator R2 consists of a pressure control valve 8, with which the lowering speed can be adjusted by means of a proportional solenoid 9, and a pressure compensator 10.
  • the pressure control valve 8 is acted upon by spring force in the direction of the shut-off position in which it is able to keep the load pressure leak-free .
  • a pilot line 11 to closing pilot pressure side 22 of the pressure compensator 10
  • a pilot line 12 to the opening pilot side 19 of the pressure compensator 10 leads.
  • At the opening pilot pressure side also acts a control spring.
  • the two-way current controller R2 is assigned an electrically operable redundancy switching element A, which is energized when the proportional magnet 9 is energized.
  • this is a 2/2-way valve 14 in poppet design, ie with leak-free closed position, which can be brought by a black / white magnet 15 against the at its opening pilot 21 from the pilot pressure in the pilot line 12a derived pressure in the closed position shown .
  • the redundancy switching element A is arranged for example parallel to the pressure relief valve 13 in the wiring harness.
  • the load pressure is held by the pressure regulating valve 8.
  • the proportional solenoid 9 receives current whose strength corresponds to the desired lowering speed.
  • the black / white magnet 15 is energized by a higher-level control, not shown, so that the redundancy switching element A assumes its shut-off position (as shown).
  • the pressure control valve 8 can flow with the energization of the proportional solenoid 9 via a metering orifice pressure medium, the pressure compensator 10 keeps the pressure difference across the orifice and thus the lowering speed constant.
  • the pressure compensator 10 adjusts itself to a position which depends on the pilot control pressures in the pilot control lines 11 and 12 and its control spring (load independence).
  • the de-energization of the proportional solenoid 9 and the black / white magnet 15 of the redundancy switching element A is de-energized, so that the redundancy switching element A abruptly by the pilot pressure in the pilot line 12a in its open position and the pilot pressure to the tank ,
  • the pressure compensator 10 is brought from the pilot pressure in the pilot control line 11 in its closed position and holds the load pressure.
  • the hydraulic cylinder Z comes to a stop.
  • the redundancy switching element A could also be energized and de-energized once or several times in the event of the pressure compensator 10 getting stuck in order to make the pressure balance 10 common again.
  • the redundancy switching member A is assigned to the three-way current regulator R1 for lifting control.
  • the redundancy switching element A is contained in a pilot line 6a branching off from the pilot line 6 to the closing pilot side 20 of the pressure compensator 5, and offers a possibility of being able to actively intervene in the event of a fault. For example, should the pressure compensator 5 become stuck due to a malfunction in a middle position, further extension of the hydraulic cylinder Z could be prevented by bringing the pressure control valve 3 into its closed position by means of the proportional magnet 4.
  • the pressure control valve 3 should hang, then the hydraulic cylinder Z would possibly be brought to a halt by switching off the motor M, but then not reliable, if at the same time other hydraulic consumers from the pressure source must be supplied with.
  • the 2/2-way valve 14 from the pilot pressure in the pilot line 6, 6a brought quickly into its open position, so that the pilot pressure is abruptly reduced to the tank and the pressure compensator 5 is brought by the prevailing pressure in the lifting strand 1 via the pilot line 7 in the full open position in which the pressure fluid from the lifting strand 1 derived to the tank and the hydraulic cylinder Z is brought to a standstill.
  • the redundancy switching element A could be used in repeated energization and de-excitation to make the hanging pressure compensator 5 common again.
  • the electro-hydraulic stroke control device S is combined with additional controls SH, SH 'for more hydraulic consumers of the industrial truck with common supply from the pressure source P is present.
  • the control SH is used, for example, to actuate a further hydraulic consumer Z ', for example a tilting cylinder or a gripper cylinder, which requires a lower supply pressure than the hydraulic cylinder Z.
  • the load pressure is brought via a pilot line 6b to the pilot line 6 and then the Schellervormatiseite 20 of the pressure compensator 5, via a shuttle valve 16, the respective higher control pressure to the Closing pilot side 20 of the pressure compensator 5 transmits.
  • the pressure compensator 5 regulates the respectively required pressure.
  • the redundancy switch A in this embodiment is operatively associated alternately with both the two-way current regulator R2 and the three-way current regulator R1 via a shuttle valve 17 (or via two separate pilot lines, as shown in FIGS. 4 and 5).
  • a shuttle valve 17 or via two separate pilot lines, as shown in FIGS. 4 and 5.
  • From the pilot control line 12 of the two-way flow controller R2 branches off a pilot line 12 'to the shuttle valve 17.
  • a pilot line 6 ' which branches off from the pilot line 6 of the three-way current regulator R1.
  • the respective higher pilot pressure is transmitted to the pilot line 18, in which optionally the pressure relief valve 13 and the redundancy switching element A are arranged.
  • the redundancy switching element A is in Fig. 3, a 2/2-way proportional pressure control valve 14 ', which is acted upon by the pilot pressure in the pilot line 18 in the opening direction at its ⁇ réellesvor Tavernseite 21, and by a proportional solenoid 15' in the direction of the closed position shown can be adjusted.
  • the energization of the proportional magnet 15 ' takes place simultaneously with the energization of the proportional magnet 4 in the lifting control, while in the lowering control simultaneously with the energization of the proportional magnet 9.
  • the proportional solenoid 15' can not only set the closed position of the redundancy switching element A, but let Optionally, depending on a weaker energization with sole or additional actuation of the hydraulic cylinder Z 'set intermediate positions to lower the pilot pressure in the pilot line 18 for the pressure compensator 5.
  • the redundancy switching element fulfills the function of an electrically adjustable pressure relief valve for adjusting the pilot pressure at the closing pilot side 20 of the pressure compensator 5, eg to set a lower supply pressure for the further hydraulic consumer Z '.
  • the redundancy switch A of this design could also be used for intentionally reducing the pilot pressure level for the lift and / or lower control.
  • the shuttle valve 17 In the lift control, the shuttle valve 17 is in its left position, so that prevails in the pilot line 18, the pilot pressure from the pilot line 6. If the pressure control valve 3 get stuck, although the proportional solenoid 4 is de-energized, the proportional solenoid 15 'is de-energized, so that the redundancy switching element A via the pilot pressure in the pilot line 18 abruptly assumes its open position and degrades the pilot pressure to the tank.
  • the pressure compensator 5 is abruptly in its open position in which the pressure medium is discharged directly to the tank and the hydraulic cylinder Z stops its extension movement, wherein the load pressure of a check valve downstream of the pressure control valve 3 and the pressure control valve 8 is maintained.
  • the shuttle valve 17 assumes the position shown, so that in the pilot line 18, the pressure of the pilot line 12 and 12 'prevails. If the pressure control valve 8 get stuck, then, as explained above, via the going into its open position redundancy switching element A, the pressure compensator 10 is brought into its closed position and held the load pressure of the hydraulic cylinder Z.
  • the proportional electronic control unit 15' is supplied with current only to such an extent by the superordinate electronic controller CU, which expediently contains a microprocessor or another logic circuit, that the pressure regulating valve 14 'assumes an intermediate position and regulates one Part of the pressure medium from the pilot pressure line 18 to the tank discharges to reduce the pilot pressure at the closing pilot side 20 of the pressure compensator 5, so that the pressure compensator 20 now controls relatively more pressure fluid to the tank and reduces the supply pressure in the pressure line 1 '.
  • Figs. 4 and 5 each have a redundancy switching element A is provided with de-energized solenoid 15 or proportional solenoid 15 ', the pilot line 12 to Senkzweig 2 shuts off and the opening pilot side 19 of the pressure compensator 10 relieved via a pilot line 12b directly to the tank.
  • the redundancy switching element A is a 4/2-way switching valve 14 "with a solenoid 15 as an actuator against a spring 26.
  • the redundancy switching element A is not used here to set a lower supply pressure for other hydraulic consumers, but to hedge the Current controller R1, R2 in case of failure and possibly for arbitrary release of the respective pressure compensator for other reasons, eg for the purpose of individual braking or for other safety-related reasons.
  • the 4/2-way switching valve 14 is a spool valve having a spool 27 which is pressure balanced with respect to tank pressure.”
  • the switching valve 14 is between the two pilot lines 12 (from the drawstring 2) and 6a (from the closing pilot side 20) of the pressure compensator 5 and optionally the shuttle valve 16 and the tank T and the pilot control line 12b to the opening pilot side 19 of the pressure compensator 10 are arranged.
  • de-energized solenoid 15 (this may be a simple black and white solenoid) is the switching position shown in which the pilot lines 12, 12b separated from each other and the pilot lines 6a and 12b are relieved together in a bypass 24 in the valve spool 27 to the tank T.
  • a switching position is set in which the pilot line 6a separated from the tank T and the pilot lines 12, 12b are connected to each other.
  • a Nutzsenk réelle 2 a which branches off between the proportional pressure control valve 8 and the pressure compensator 10 from the Senkstrang 2 and is connected to the suction side of the pump P.
  • a check valve V is indicated, which blocks in the direction of the tank to promote the lowering of the pressure medium by the pump P and to drive this as a motor for the then working as a generator electric motor for energy recovery at Nutzsenken.
  • the pressure medium then flows via the pressure compensator 20 to the tank, or, if further hydraulic consumers are connected and supplied, on. If a speed-controllable pump P is used, the pressure compensator 10 is set in the case of the connection of further hydraulic consumers the amount just required each time by the pump P.
  • the pay reduction option can be easily integrated into any embodiment shown.
  • the redundancy switching element A is a 4/3-proportional pressure regulating valve 14 "'with the proportional solenoid 15' as an actuator of the valve spool 27 'against the force of a spring 26 and the pilot pressure in a pilot line 6c, that of the pilot control line
  • the further connection corresponds to that already shown in Fig. 4.
  • the valve spool 27 ' is pressure-balanced with respect to the tank pressure via the pilot control line 25, expediently over the full area, while the pilot pressure from the pilot control line 6c expediently only a partial area of the surface of the valve spool 27 acted upon the proportional solenoid 15 'in order to use a weak and compact or inexpensive proportional magnet 15' can.
  • pilot pressure at the closing pilot side 20 of the pressure compensator 5 in the lift control or in controlling further hydraulic consumers to reduce their supply pressure e.g. the proportional solenoid 15 'in accordance with the desired pilot pressure in the pilot line 6a energized weaker than in the protection of the respective current regulator to take between end positions with significant coverage regulating intermediate switch positions in which both the pilot lines 12, 12b are connected to each other and the pilot line 6a directly connected to the tank.

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Description

Die Erfindung betrifft eine elektrohydraulische Hubsteuervorrichtung der im Oberbegriff des Anspruchs 1 angegebenen Art.The invention relates to an electro-hydraulic stroke control device specified in the preamble of claim 1 Art.

Bei der aus DE 42 39 321 C bekannten elektrohydraulischen Hubsteuervorrichtung sind als elektrisch betätigbare Komponenten nur die Proportional-Druckregelventile für die Hebesteuerung und die Senksteuerung vorhanden. Die Sicherheitsanforderungen sind speziell bei Flurförderfahrzeugen, insbesondere Hubstaplern, sehr hoch. Verschmutzungen im Hydraulikmedium, z.B. Späne oder dgl., lassen sich nicht mit 100%iger Sicherheit vermeiden. Solche Verunreinigungen können dazu führen, dass beispielsweise das Proportional-Druckregelventil der Senksteuerung oder der Hebesteuerung hängen bleibt und sich nicht mehr verstellen lässt, so dass die vom Hydraulikzylinder getragene Last unkontrolliert absinkt oder nachläuft. Der Proportionalmagnet erzeugt eine Kraft, die dann nicht ausreicht, den erhöhten Bewegungswiderstand im Ventil zu überwinden. Dies bedeutet ein erhöhtes Sicherheitsrisiko, das es bei früheren, mechanisch betätigten hydraulischen Hubsteuervorrichtungen nicht gab, da dort nur die mechanische Kraft entsprechend erhöht zu werden brauchte, um einen solchen Widerstand zu überwinden.At the DE 42 39 321 C known electro-hydraulic stroke control device are present as electrically actuated components only the proportional pressure control valves for the lifting control and the lowering control. The safety requirements are very high especially for industrial trucks, especially forklifts. Dirt in the hydraulic medium, eg chips or the like, can not be avoided with 100% certainty. Such contaminants may cause, for example, the proportional pressure control valve of the lowering control or the lifting control to become stuck and can no longer be adjusted, so that the load borne by the hydraulic cylinder falls or runs uncontrolled. The proportional solenoid generates a force that is then insufficient to overcome the increased resistance to movement in the valve. This means an increased safety risk, which did not exist in earlier, mechanically actuated hydraulic Hubsteuervorrichtungen, since there only the mechanical force had to be increased accordingly to overcome such a resistance.

Bei dem aus DE 100 10 670 A bekannten elektrisch steuerbaren Hubmodul (Fig. 1) ist der Dreiwege-Stromregler im Senkzweig abströmseitig mit dem Tank und zur Energierückgewinnung mit der Saugseite der Pumpe verbunden. Im Hebestrang ist, da die Geschwindigkeit des Hydraulikzylinders über die Drehzahl der Pumpe gesteuert wird, nur ein Schwarz/Weiß-2/2-Magnetwegeventil vorgesehen. Vom Hebestrang zweigt eine Ablassleitung mit einem 2/2-Wege-Magnetschaltventil zum Tank ab, das beim Nutzsenken elektrisch auf Durchgang geschaltet wird, falls kein zusätzlicher Verbraucher zu versorgen ist. Sollte der Dreiwege-Stromregler verschmutzungsbedingt im Senkbetrieb hängen bleiben, dann fährt der Hubzylinder unkontrolliert ein.At the DE 100 10 670 A known electrically controllable lifting module (Fig. 1) is the three-way flow regulator in the Senkzweig downstream connected to the tank and for energy recovery with the suction side of the pump. In the lifting strand, since the speed of the hydraulic cylinder is controlled by the speed of the pump, only one black / white 2/2 solenoid valve is provided. From the lifting strand branches off a drain line with a 2/2-way solenoid valve to the tank, which is electrically connected to the passageway during sinking, if no additional consumer is to be supplied. If the three-way current regulator gets stuck in lowering mode as a result of pollution, the lifting cylinder will stop moving in an uncontrolled manner.

Bei der aus DE 41 40 408 A bekannten Hub-Steuervorrichtung sind zur Hebe- und Senksteuerung zwei Proportional-Druckregelventile vorgesehen. Sollte im Senkbetrieb das Proportional-Druckregelventil verschmutzungsbedingt hängen bleiben, fährt der Hubzylinder unkontrolliert unter Last ein.At the DE 41 40 408 A Known stroke control device are provided for raising and lowering control two proportional pressure control valves. Should be in lowering mode the proportional pressure control valve gets stuck due to contamination, the lifting cylinder moves uncontrollably under load.

Weiterer Stand der Technik ist enthalten in EP 0 546 300 A , EP 0 893 607 A , US 5 701 618 A .Further prior art is contained in EP 0 546 300 A . EP 0 893 607 A . US 5,701,618 A ,

Bei elektrisch gesteuerten Hubstaplern, unabhängig davon, ob sie motorbetrieben oder elektrisch betrieben sind, zeichnet sich ein Trend nach erhöhter Sicherheit dahingehend ab, für den Ausfall eines elektrisch gesteuerten Regel- oder Steuerorgans zumindest des Hubzylinders weitere elektrisch betätigbare Sicherheitseinrichtungen vorzusehen, die, u.a. zum Personenschutz, ein Herabfallen der Last verhindern sollen. Von derselben Druckquelle versorgte Nebenverbraucher arbeiten oft mit einem niedrigeren Druck als der Haupthubzylinder. Diese Forderungen lassen sich zwar mit an verschiedenen Punkten in der Steuervorrichtung platzierten, elektrisch betätigbaren Ventilen erfüllen, jedoch bedingt dies einen Mehraufwand an Ventilen und Betätigungsmagneten oder teuren Proportionalmagneten mit aufwendiger Verkabelung.In electrically controlled lift trucks, regardless of whether they are powered by engines or electrically operated, a trend towards increased safety is to provide for the failure of an electrically controlled control or control member at least the lifting cylinder further electrically actuated safety devices, which, u.a. for personal protection, to prevent the load from falling down. Secondary consumers supplied by the same pressure source often operate at a lower pressure than the main lift cylinder. Although these requirements can be fulfilled with electrically actuatable valves placed at different points in the control device, this requires an additional expenditure of valves and actuation magnets or expensive proportional solenoids with complicated wiring.

Der Erfindung liegt die Aufgabe zugrunde, eine elektrohydraulische Hubsteuervorrichtung dieser Art anzugeben, deren Betriebssicherheit gegen Störungen aufgrund von Verunreinigungen des Hydraulikmediums oder sich entwickelnder mechanischer Schäden hydraulischer Schaltglieder mit minimalem Aufwand erhöht ist.The invention has for its object to provide an electro-hydraulic stroke control device of this type, the reliability is increased against disturbances due to contamination of the hydraulic medium or developing mechanical damage hydraulic switching elements with minimal effort.

Als Nebenaspekt im Rahmen dieser Aufgabe soll ohne Mehraufwand ferner bei der Senksteuerung eine zusätzlich aktivierbare Bremsfunktion möglich sein, oder ist ein absichtliches aktives Freischalten eines oder beider Stromregler wünschenswert, oder soll sich der Versorgungsdruck für wenigstens einen weiteren Hydroverbraucher auf einfache Weise mit minimalem Aufwand niedriger einstellen lassen als z.B. für die Hebesteuerung. Der erwähnte Aufwand bezieht sich hierbei hauptsächlich auf Magneten als Ventilbetätiger.As a side aspect in the context of this task should also be possible without additional effort in the lowering control an additional activatable braking function, or intentional active disconnection of one or both current regulator is desirable, or should adjust the supply pressure for at least one other hydraulic consumer in a simple manner with minimal effort leave as eg for lifting control. The mentioned effort relates mainly to magnets as a valve actuator.

Die gestellte Aufgabe wird erfindungsgemäß mit den Merkmalen des Anspruchs 1 gelöst.The stated object is achieved with the features of claim 1.

Die Betriebssicherheit der elektrohydraulischen Hubsteuervorrichtung ist erhöht, weil das Redundanz-Schaltglied dann aktiv eingreift, wenn wenigstens ein anderes elektrisch betätigbares Schaltglied nicht mehr ordnungsgemäß funktionieren sollte. Durch den aktiven Eingriff des Redundanz-Schaltgliedes werden vor allem unkontrollierte Lastbewegungen bzw. ein ungewolltes Absenken der Last vermieden. Bleibt beispielsweise das Proportional-Druckregelventil bei der Senksteuerung oder der Hebesteuerung hängen, so dass es sich durch seinen Proportionalmagneten nicht mehr verstellen lässt (der Hubhydraulikzylinder würde dann entweder unter der Last einfahren oder gegen die Last ausfahren), dann bringt das dann wirksame Redundanz-Schaltglied in der Öffnungsstellung entweder die Druckwaage des Zweiwege-Stromreglers in die lasthaltende Absperrstellung (Anhalten des absinkenden Hubhydraulikzylinders) oder die Druckwaage des Dreiwege-Stromreglers in die Öffnungsstellung (Ableiten des Stromes zum Tank, so dass der Hubhydraulikzylinder anhält). Bei ordnungsgemäßer Funktion des Proportionaldruckregelventiis nimmt das Redundanz-Schaltglied keinen Einfluss im jeweiligen Vorsteuerkreis, da es mit Bestromung des jeweiligen Proportionalmagneten bestromt wird und seine Schließstellung hält. Das Redundanz-Schaltglied ist eine einfach zu integrierende Sicherheitskomponente und erfordert nur minimalen Aufwand. Für diese Funktion ist für die Steuerelektronik nur der Magnet des Schaltglieds und hydraulisch ein einfaches, kleinbauendes Ventil für das Vorsteueröl erforderlich.The reliability of the electro-hydraulic Hubsteuervorrichtung is increased because the redundancy switching element then actively engages when at least one other electrically actuated switching element should not work properly. Due to the active engagement of the redundancy switching element, in particular uncontrolled load movements or unintentional lowering of the load are avoided. If, for example, the proportional pressure control valve remains stuck in the lowering control or the lifting control, so that it can no longer be adjusted by its proportional magnet (the lifting hydraulic cylinder would then either move under the load or extend against the load), then the effective redundancy switching element is brought in the open position either the pressure compensator of the two-way flow regulator in the load-holding shut-off position (stopping the sinking Hubhydraulikzylinders) or the pressure compensator of the three-way flow regulator in the open position (deriving the flow to the tank, so that the hydraulic cylinder stops). With proper function of the Proportionaldruckregelventiis the redundancy switching element has no influence in the respective pilot circuit, since it is energized with energization of the respective proportional solenoid and holds its closed position. The redundancy switching element is an easy-to-integrate safety component and requires only minimal effort. For this function, only the magnet of the switching element and hydraulically a simple, small-sized valve for the pilot oil is required for the control electronics.

Das Redundanz-Schaltglied bietet dank seiner Anordnung jedoch weitere vorteilhafte Möglichkeiten, wobei vorauszusetzen ist, dass die bei modernen Flurförderfahrzeugen vorgesehene elektronische Steuerung einen Mikroprozessor enthält, der viele Möglichkeiten für individuelle Programmroutinen oder Funktionen bietet. Durch Verstellen des Redundanz-Schaltgliedes in die Öffnungsstellung während der Senksteuerung kann beispielsweise die Senkbewegung zusätzlich individuell abgebremst werden, indem die Druckwaage des Zweiwege-Stromreglers auf andere Weise in die Schließstellung gebracht wird, als durch die Druckdifferenz des Proportionaldruckregelventils. Eine ähnliche individuelle Bremsung könnte auch bei der Hebesteuerung über die Druckwaage des Dreiwege-Stromreglers erfolgen. Weiterhin kann das Redundanz-Schaltglied den Zweiwege-Stromregler oder den Dreiwege-Stromregler aktiv freischalten, d.h. die jeweilige Druckwaage in die Schließstellung bzw. volle Öffnungsstellung bringen. Schließlich kann das Redundanz-Schaltglied als variables Druckbegrenzungsventil den Vorsteuerdruck der Druckwaage des Dreiwege-Stromreglers verändern, die den Versorgungsdruck für wenigstens einen weiteren Hydroverbraucher einstellt, der niedriger ist als der des Hub-Hydraulikzylinders. Es eröffnet das Redundanz-Schaltglied im Zusammenspiel mit der Steuerelektronik Möglichkeiten für eine universellere Steuerung des Flurförderfahrzeuges, wobei die an sich gegebene Leistungsfähigkeit der übergeordneten Elektronik ohne Mehraufwand genutzt wird.However, thanks to its arrangement, the redundancy switching element offers further advantageous possibilities, whereby it must be assumed that the electronic control provided in modern industrial trucks contains a microprocessor which offers many possibilities for individual program routines or functions. By adjusting the redundancy switching element in the open position during the lowering control, for example, the lowering movement can be additionally braked individually by the pressure compensator of the two-way flow regulator is brought in another way in the closed position, as by the pressure difference of the proportional pressure control valve. A similar individual braking could also be done in the lift control via the pressure compensator of the three-way current controller. Furthermore, the redundancy switching element can actively activate the two-way current regulator or the three-way current regulator, ie the respective pressure compensator into the closed position or full open position bring. Finally, the redundancy switching element as a variable pressure limiting valve change the pilot pressure of the pressure compensator of the three-way flow regulator, which adjusts the supply pressure for at least one further hydraulic consumer, which is lower than that of the lifting hydraulic cylinder. It opens up the redundancy switching element in conjunction with the control electronics possibilities for a more universal control of the industrial truck, the inherent performance of the parent electronics is used without additional effort.

Das Redundanz-Schaltglied sollte zwischen dem Tank und entweder der Öffnungs-Vorsteuerseite der Druckwaage des Zweiwege-Stromreglers und/oder der Schließvorsteuerseite der Druckwaage des Dreiwege-Stromreglers angeordnet sein. In dieser Position entlastet das Redundanz-Schaltglied bei aktiver Betätigung den Vorsteuerdruck für die jeweilige Druckwaage, so dass diese zwangsweise in ihre Schließstellung bzw. Durchgangsstellung geht.The redundancy switch should be located between the tank and either the opening pilot side of the pressure balance of the two-way flow regulator and / or the closing pilot side of the pressure balance of the three-way flow regulator. In this position, the redundancy switching element relieved when actuated, the pilot pressure for the respective pressure compensator, so that it forcibly goes into its closed position or passage position.

Um eine feinfühlige Regelung der Druckentlastung durch das Redundanz-Schaltglied einstellen zu können, ist es zweckmäßig, dieses als 2/2-Wege-Regelventil mit Druckvorsteuerung in Öffnungsrichtung und einem Proportionalmagneten als Aktuator zum Verstellen in Schließrichtung auszulegen. Diese Auslegung ist dann vorteilhaft, wenn das Redundanz-Schaltglied als variables Druckbegrenzungsventil den Vorsteuerdruck individuell einzustellen hat. Für den gewünschten Sicherheitsaspekt reicht es allerdings aus, das Redundanz-Schaltglied nur zwischen einer Öffnungs- und einer Schließstellung umstellen zu können (Schwarz/Weiß-Funktion).In order to be able to set a sensitive control of the pressure relief by the redundancy switching element, it is expedient to interpret this as a 2/2-way control valve with pressure precontrol in the opening direction and a proportional solenoid as an actuator for adjusting in the closing direction. This design is advantageous if the redundancy switching element as a variable pressure relief valve has to adjust the pilot pressure individually. However, for the desired safety aspect, it is sufficient to be able to change the redundancy switching element only between an open and a closed position (black / white function).

Aus diesem Grund reicht nur für erhöhte Sicherheitsanforderungen als Redundanz-Schaltglied ein 2/2-Wegeventil mit Druckvorsteuerung in Öffnungsrichtung und einem Schwarz/Weiß-Magneten als Aktuator zur Verstellung in Schließrichtung aus. Ein 2/2-Wegeventil dieser Bauart ist kostengünstig und funktionssicher. Zweckmäßigerweise ist das Redundanz-Schaltglied hier ein Sitzventil, das sich durch eine leckagefreie Schließstellung auszeichnet.For this reason, a 2/2-way valve with pressure pre-control in the opening direction and a black / white magnet as an actuator for adjustment in the closing direction is sufficient only for increased safety requirements as a redundancy switching element. A 2/2-way valve of this type is inexpensive and reliable. Conveniently, the redundancy switching element is here a seat valve, which is characterized by a leak-free closed position.

Zweckmäßig wird die Druckvorsteuerung des Redundanz-Schaltgliedes, mit der das Redundanz-Schaltglied in seine Öffnungsstellung gebracht wird, mit der Öffnungs-Vorsteuerseite der Druckwaage des Zweiwege-Stromreglers oder der Schließvorsteuerseite der Druckwaage des Dreiwege-Stromreglers verbunden. Solange Vorsteuerdruck an der jeweiligen Druckwaage ansteht, wird das Redundanz-Schaltglied dadurch in Richtung auf seine Öffnungsstellung beaufschlagt, die es allerdings nur dann einzunehmen vermag, wenn es nicht aktiv elektrisch in seine Schließstellung verstellt ist.Suitably, the pressure precontrol of the redundancy switching element, with which the redundancy switching element is brought into its open position, with the opening pilot side the pressure compensator of the two-way flow regulator or the Schließvorsteuerseite the pressure compensator of the three-way current controller connected. As long as pilot pressure is applied to the respective pressure compensator, the redundancy switching element is thereby acted upon in the direction of its open position, which, however, it is only able to take if it is not actively adjusted electrically in its closed position.

Eine weitere Erhöhung der Betriebssicherheit lässt sich erzielen, wenn das Redundanz-Schaltglied beiden Stromreglern zugeordnet ist und seine Funktion für den jeweiligen Stromregler abhängig vom Druck erfüllt. D.h., das Wechselventil verbindet jeweils die arbeitende Druckwaage mit dem Redundanz-Schaltglied, wobei dann der ausgewählte Vorsteuerdruck oder der höhere Vorsteuerdruck ansteht. Das Redundanz-Schaltglied arbeitet somit automatisch bei der Hebesteuerung mit dem Dreiwege-Stromregler, hingegen bei der Senksteuerung mit dem Zweiwege-Stromregler zusammen.A further increase in operational safety can be achieved if the redundancy switching element is assigned to both current regulators and fulfills its function for the respective current regulator as a function of the pressure. That is, the shuttle valve connects each of the working pressure compensator with the redundancy switch member, in which case the selected pilot pressure or the higher pilot pressure is applied. The redundancy switching element thus operates automatically in the lift control with the three-way current controller, while in the lowering control with the two-way current controller together.

Zweckmäßig kann das Redundanz-Schaltglied parallel zu einem Steuerdruck-Druckbegrenzungsventil angeordnet sein. Dies bietet bauliche Vorteile, weil ohnedies ein Vorsteuerdruckkanal über das Druckbegrenzungsventil zum Tank oder zur Rücklaufleitung verläuft. Wenn das Redundanz-Schaltglied als durch einen Proportionalmagneten betätigbares Druckregelventil ausgebildet ist, das bei variierender Bestromung die Funktion eines Druckbegrenzungsventils übernimmt, kann das Druckbegrenzungsventil gegebenenfalls weggelassen werden.Suitably, the redundancy switching element can be arranged parallel to a control pressure-relief valve. This offers structural advantages, because in any case a pilot pressure duct runs via the pressure limiting valve to the tank or to the return line. If the redundancy switching element is designed as a pressure control valve which can be actuated by a proportional magnet and which assumes the function of a pressure-limiting valve with varying energization, the pressure-limiting valve can optionally be omitted.

Das Redundanz-Schaltglied kann, geführt durch die Steuerelektronik und, wie erwähnt, bei Auslegung als Proportional-Druckregelventil, die Funktion eines elektrisch verstellbaren Druckbegrenzungsventils erfüllen, damit die Druckwaage des Dreiwege-Stromreglers für weitere Hydroverbraucher einen niedrigeren Versorgungsdruck einstellt. Alle vorerwähnten Funktionen lassen sich mit einem kleinen Ventil und einem Magneten erzielen.The redundancy switching element, performed by the control electronics and, as mentioned, when configured as a proportional pressure control valve, perform the function of an electrically adjustable pressure relief valve, so that the pressure compensator of the three-way flow control adjusts a lower supply pressure for other hydraulic consumers. All the aforementioned functions can be achieved with a small valve and a magnet.

Da das im Vorsteuerkreis angeordnete Redundanz-Schaltglied bei einer Störung beispielsweise des Dreiwege-Stromreglers bei der Senksteuerung in seine Öffnungsstellung geht, sobald der Proportionalmagnet des Dreiwege-Stromreglers stromlos ist, könnte der Hub-Hydraulikzylinder über den Vorsteuerkreis trotz der Lasthaltefunktion der Druckwaage sehr langsam nachgeben. Aus diesem Grund ist es zweckmäßig, das Redundanz-Schaltglied als 4/2-Wege-Schaltventil mit einem Schaltmagneten als Aktuator auszubilden und die Vorsteuerleitung zum Senkzweig zumindest staplerdicht abzusperren, während die Öffnungs-Vorsteuerseite der Druckwaage direkt zum Tank entlastet wird. Daraus resultiert eine einwandfreie Lasthaltefunktion der Druckwaage, so dass der Hub-Hydraulikzylinder selbst bei hängengebliebenem Proportional-Wegedruckregelventil zuverlässig angehalten bleibt.Since arranged in the pilot circuit redundancy switching element in case of failure, for example, the three-way current regulator in the lowering control in its open position goes, as soon as the proportional solenoid of the three-way current regulator is de-energized, the stroke hydraulic cylinder could give way very slowly over the pilot circuit despite the load-holding function of the pressure compensator. For this reason, it is expedient to form the redundancy switching element as a 4/2-way switching valve with a solenoid as the actuator and shut off the pilot line to Senkzweig at least stacker-tight, while the opening pilot side of the pressure compensator is relieved directly to the tank. This results in a perfect load-holding function of the pressure balance, so that the lifting hydraulic cylinder remains reliably stopped even when stuck proportional-pressure relief valve.

Um diesen hohen Sicherheitsstandard auch dann gewährleisten zu können, wenn das Redundanz-Schaltglied die Funktion der Druckabsenkung für weitere Verbraucher ausführen soll, ist es zweckmäßig, das Redundanz-Schaltglied sogar als 4/3-Wege-Proportionaldruckregelventil mit einem Proportionalmagneten als Aktuator auszubilden und die beiden Vorsteuerleitungen vom Senkzweig und von der Schließ-Vorsteuerseite der Druckwaage des Zweiwege-Stromreglers getrennt anzuschließen. Wird das 4/3-Wege-Proportionaldruckregelventil bei Abbruch der Senksteuerung entregt, dann nimmt es seine Abschaltstellung ein, in der die Öffnungs-Vorsteuerseite der Druckwaage des Zweiwege-Stromreglers zum Tank entlastet und die Druckwaage zum Lasthalten eingestellt wird. Diese Schaltstellung wird auch eingenommen, wenn die Hebesteuerung abgebrochen wird. Dann ist die Schließ-Vorsteuerseite der Druckwaage des Dreiwege-Stromreglers zum Tank entlastet, so dass die Druckwaage, falls Versorgungsdruck ansteht, in die Schließstellung eingestellt wird. Sobald zur Hebesteuerung oder Senksteuerung einer der Proportionalmagneten der Stromregler bestromt wird, wird auch der Proportionalmagnet des 4/3-Wege-Proportionaldruckregelventils voll bestromt. Die dadurch erzeugte Schaltstellung stellt die Vorsteuerleitung von dem Senkzweig zur Öffnungs-Vorsteuerseite der Druckwaage des Zweiwege-Stromreglers auf Durchgang und unterbricht die Verbindung der Vorsteuerleitung zur Schließ-Vorsteuerseite der Druckwaage des Dreiwege-Stromreglers zum Tank. Ist hingegen bei der Hebesteuerung ein weiterer Verbraucher zugeschaltet, dann wird der Proportionalmagnet des 4/3-Wege-Proportionaldruckregelventils nach Maßgabe der gewünschten Druckminderung gegen die Regelfeder und den Vorsteuerdruck mit einem Stromwert beaufschlagt, mit dem eine Regelfunktion zum Vermindern des Vorsteuerdrucks für die Druckwaage des Dreiwege-Stromreglers ausgeführt wird. Alle diese Funktionen werden mit einem einzigen Ventil und nur einem einzigen Proportionalmagneten erzielt.In order to ensure this high safety standard even if the redundancy switching element is to perform the function of reducing the pressure for other consumers, it is expedient to form the redundancy switching element even as a 4/3-way proportional pressure control valve with a proportional solenoid as the actuator and the separate two pilot control lines from Senkzweig and from the closing pilot side of the pressure compensator of the two-way current controller separately. If the 4/3-way proportional pressure control valve de-energized when canceling the lowering control, then it assumes its shutdown, in which relieves the opening pilot side of the pressure compensator of the two-way flow controller to the tank and the pressure compensator is set to load. This shift position is also assumed when the lift control is canceled. Then the closing pilot side of the pressure compensator of the three-way flow regulator is relieved to the tank, so that the pressure compensator, if supply pressure is present, is set in the closed position. As soon as the current controller is energized for lifting control or lowering control of one of the proportional solenoids, the proportional solenoid of the 4/3-way proportional pressure control valve is also fully energized. The switching position generated thereby sets the pilot line from the Senkzweig to the opening pilot side of the pressure compensator of the two-way flow regulator on passage and interrupts the connection of the pilot line to the closing pilot side of the pressure compensator of the three-way flow regulator to the tank. If, however, another consumer is connected in the lift control, then the proportional solenoid of the 4/3-way proportional pressure control valve is subjected to a current value in accordance with the desired pressure reduction against the control spring and the pilot pressure a control function for reducing the pilot pressure for the pressure compensator of the three-way current controller is executed. All these functions are achieved with a single valve and a single proportional solenoid.

Zweckmäßig wird das 4/2-Wegeschaltventil bzw. das 4/3-Wege-Proportionaldruckregelventil als Schieberventil in staplerdichter Ausführung ausgebildet. Dies bedeutet, dass das Ventil die an das Kriterium der Staplerdichtheit gültige Anforderung erfüllt.Suitably, the 4/2-way switching valve or the 4/3-way proportional pressure control valve is designed as a slide valve in stapler-tight design. This means that the valve fulfills the requirement valid for the stacker leak criterion.

Um mit einem möglichst klein bauenden und schwachen und damit kostengünstigen Schaltmagneten oder Proportionalmagneten für das Redundanz-Schaltglied auszukommen, ist es zweckmäßig, in dem Schieberventil einen bezüglich des Tankdrucks druckausgeglichenen Ventilschieber vorzusehen. Falls das Redundanz-Schaltglied auch die Druckbegrenzung für die weiteren Verbraucher steuert, ist es besonders zweckmäßig, den Vorsteuerdruck, gegen den der Proportionalmagnet arbeitet, nur auf einer kleinen Teilfläche des Ventilschiebers wirken zu lassen.To get along with the smallest possible and weak and therefore cost-effective solenoids or proportional magnets for the redundancy switching element, it is expedient to provide a pressure-balanced with respect to the tank pressure valve slide in the slide valve. If the redundancy switching element also controls the pressure limit for the other consumers, it is particularly expedient to let the pilot pressure, against which the proportional solenoid operates, act only on a small partial area of the valve slide.

Die elektrohydraulische Hubsteuervorrichtung ist mit dieser Auslegung sowohl für Hubstapler mit einem Verbrennungskraftmotor als auch einem Elektromotor verwendbar. Bei elektromotorisch angetriebenen Hubstaplern kann die Hubsteuervorrichtung ohne oder mit Energierückgewinnung (Nutzsenken) verwendet werden. Für Nutzsenkbetrieb, bei dem der Elektromotor über die Pumpe als Generator betrieben wird, ist es nur erforderlich, den Senkzweig stromauf der Druckwaage des Zweiwege-Stromreglers über eine Nutzleitung mit der Saugseite der Pumpe zu verbinden, und zwischen der Pumpe und dem Tank ein Rückschlagventil anzuordnen. Bei hohem Lastdruck und ohne zugeschaltete weitere Hydraulikverbraucher kann die volle Menge (durch die Druckwaage des Zweiwege-Stromreglers gesteuert) durch die Pumpe gefördert werden. Ist ein weiterer Hydraulikverbraucher zugeschaltet, dann regelt die Druckwaage des Zweiwege-Stromreglers beim Nutzsenken einen Strom durch die Pumpe ein, der dem momentanen Bedarf entspricht. Das Redundanz-Schaltglied greift bei ordnungsgemäßer Funktion nicht ein, sondern nur bei einer Störung, und fallweise bei der Druckminderung für die weiteren Verbraucher.The electro-hydraulic stroke control device is usable with this design both for lift trucks with an internal combustion engine and an electric motor. In electric motor driven lift trucks, the Hubsteuervorrichtung can be used without or with energy recovery (Nutzsenken). For payload operation in which the electric motor is operated as a generator via the pump, it is only necessary to connect the Senkzweig upstream of the pressure compensator of the two-way flow regulator via a Nutzleitung with the suction side of the pump, and to arrange a check valve between the pump and the tank , At high load pressure and without additional connected hydraulic consumers, the full amount (controlled by the pressure compensator of the two-way flow regulator) can be pumped through the pump. If another hydraulic consumer is switched on, then the pressure compensator of the two-way current regulator regulates a current through the pump when it is being used, which corresponds to the current demand. The redundancy switching element does not intervene in case of proper function, but only in the case of a fault, and occasionally in the pressure reduction for the other consumers.

Die elektrisch aktiv betätigbaren Komponenten der Hubsteuervorrichtung sollten mit einer einen Mikroprozessor oder eine Logikschaltung enthaltenden elektronischen Steuerung verbunden sein, die die unterschiedlichen Betätigungsroutinen nach Bedarf, wie gewählt, oder nach einem automatisierten Schema ausführt.The electrically operable components of the stroke control device should be connected to an electronic controller including a microprocessor or logic circuit which executes the different operating routines as needed, as selected, or according to an automated scheme.

Anhand der Zeichnung werden Ausführungsformen des Erfindungsgegenstandes erläutert. Es zeigen:

Fig. 1
ein Blockschaltbild einer elektrohydraulischen Hubsteuervorrichtung mit einem Redundanz-Schaltglied, das der Senksteuerung zugeordnet ist,
Fig. 2
ein Blockschaltbild einer elektrohydraulischen Hubsteuervorrichtung mit einem Redundanz-Schaltglied, das der Hebesteuerung zugeordnet ist,
Fig. 3
ein Blockschaltbild einer elektrohydraulischen Hubsteuervorrichtung mit weiteren Hydroverbraucher, mit einem Redundanz-Schaltglied, das der Hebesteuerung und der Senksteuerung zugeordnet ist, und bei Zuordnung zur Hebesteuerung zusätzlich als elektrisch verstellbares Druckbegrenzungsventil zur Druckminderung für die weiteren Hydroverbraucher dient,
Fig. 4
ein Blockschaltbild einer weiteren Ausführungsvariante, und
Fig. 5
ein Blockschaltbild einer noch weiteren Ausführungsvariante.
Reference to the drawings, embodiments of the subject invention will be explained. Show it:
Fig. 1
FIG. 2 is a block diagram of an electro-hydraulic lift control device having a redundancy switch associated with the lowering control. FIG.
Fig. 2
FIG. 2 is a block diagram of an electro-hydraulic lift control device having a redundancy switch associated with the lift control. FIG.
Fig. 3
a block diagram of an electro-hydraulic lifting control device with further hydraulic consumer, with a redundancy switching element, which is associated with the lifting control and the lowering control, and additionally serves as an electrically adjustable pressure relief valve for pressure reduction for the other hydraulic consumers when assigned to the lifting control,
Fig. 4
a block diagram of another embodiment, and
Fig. 5
a block diagram of yet another embodiment.

In der elektrohydraulischen Hubsteuervorrichtung S in Fig. 1 wird ein Hydraulikzylinder Z zur Hebesteuerung aus einer Druckquelle P (Hydraulikpumpe) versorgt, die z.B. durch Elektromotor oder Dieselmotor M angetrieben ist und, falls keine weiteren Hydroverbraucher zu versorgen sind, bei der Senksteuerung des Hydraulikzylinders Z stehen kann, oder (Fig. 4) dann zur Energierückgewinnung als Motor läuft. Die Hydraulikpumpe saugt aus einem Tank T an und beaufschlagt einen Hebestrang 1, in welchem ein Dreiwege-Stromregler R1 vorgesehen ist. Der Dreiwege-Stromregler R1 besteht aus einem Proportional-Druckregelventil 3, mit dem die Hebegeschwindigkeit durch einen Proportionalmagneten 4 eingestellt wird, und einer Druckwaage 5 zwischen dem Hebestrang 1 und dem Tank T. Das Druckregelventil 3 wird durch Federbelastung in Richtung zur Absperrstellung beaufschlagt. Zwischen dem Hydraulikzylinder Z und dem Druckregelventil 3 zweigt eine Vorsteuerleitung 6 zur Schließ-Vorsteuerseite (an der auch eine Regelfeder wirkt) der Druckwaage 5 ab. Vom Hebestrang 1 zweigt stromauf des Druckregelventils 3 eine weitere Vorsteuerleitung 7 zur Öffnungs-Vorsteuerseite der Druckwaage 5 ab.In the electrohydraulic stroke control device S in Fig. 1, a hydraulic cylinder Z for lifting control from a pressure source P (hydraulic pump) is supplied, which is driven for example by electric motor or diesel engine M and, if no further hydraulic consumers are to be supplied, in the lowering control of the hydraulic cylinder Z are can, or (Fig. 4) then runs for energy recovery as a motor. The hydraulic pump sucks from a tank T and acts on a lifting strand 1, in which a three-way flow regulator R1 is provided. The three-way flow regulator R1 consists of a proportional pressure control valve 3, with which the lifting speed is set by a proportional solenoid 4, and a pressure compensator 5 between the lifting strand 1 and the tank T. The pressure control valve 3 is acted upon by spring loading in the direction of the shut-off position. Between the hydraulic cylinder Z and the pressure control valve 3, a pilot control line 6 branches off to the closing pilot side (at which a control spring also acts) of the pressure compensator 5. From the lifting strand 1 branches off upstream of the pressure control valve 3, a further pilot line 7 to the opening pilot side of the pressure compensator 5 from.

Vom Hebestrang 1 zweigt zwischen dem Druckregelventil 3 und dem Hydraulikzylinder Z ein Senkstrang 2 zum Tank ab, in dem zur Senksteuerung ein Zweiwege-Stromregler R2 enthalten ist. Der Zweiwege-Stromregler R2 besteht aus einem Druckregelventil 8, mit dem sich die Senkgeschwindigkeit mittels eine Proportionalmagneten 9 einstellen lässt, und einer Druckwaage 10. Das Druckregelventil 8 wird durch Federkraft in Richtung auf die Absperrstellung beaufschlagt, in der es den Lastdruck leckagefrei zu halten vermag. Zwischen dem Druckregelventil 8 und dem Hydraulikzylinder Z zweigt vom Senkstrang 2 eine Vorsteuerleitung 11 zur Schließ-Vorsteuerdruckseite 22 der Druckwaage 10 ab, während zwischen der Druckwaage 10 und dem Druckregelventil 8 vom Senkstrang 2 eine Vorsteuerleitung 12 zur Öffnungs-Vorsteuerseite 19 der Druckwaage 10 führt. An der Öffnungs-Vorsteuerdruckseite wirkt auch eine Regelfeder. Von der Vorsteuerleitung 12 zweigt eine Vorsteuerleitung 12a zum Tank T ab, in der z. B. ein Druckbegrenzungsventil 13 enthalten ist.From the lifting rope 1 branches off between the pressure control valve 3 and the hydraulic cylinder Z a Senkstrang 2 from the tank, in which the lowering control a two-way flow regulator R2 is included. The two-way flow regulator R2 consists of a pressure control valve 8, with which the lowering speed can be adjusted by means of a proportional solenoid 9, and a pressure compensator 10. The pressure control valve 8 is acted upon by spring force in the direction of the shut-off position in which it is able to keep the load pressure leak-free , Between the pressure control valve 8 and the hydraulic cylinder Z branches from the Senkstrang 2 a pilot line 11 to closing pilot pressure side 22 of the pressure compensator 10, while between the pressure compensator 10 and the pressure control valve 8 from the Senkstrang 2 a pilot line 12 to the opening pilot side 19 of the pressure compensator 10 leads. At the opening pilot pressure side also acts a control spring. From the pilot control line 12 branches off a pilot line 12a to the tank T, in the z. B. a pressure relief valve 13 is included.

Zusätzlich zu den beiden aktiv elektrisch betätigbaren Komponenten (Proportionalmagneten 4, 9) ist dem Zweiwege-Stromregler R2ein elektrisch betätigbares Redundanz-Schaltglied A zugeordnet, das bei Bestromen des Proportional-Magneten 9 bestromt wird. Bei der gezeigten Ausführungsform ist dies ein 2/2-Wegeventil 14 in Sitzventilbauweise, d.h. mit leckagefreier Schließstellung, das durch einen Schwarz/Weiß-Magneten 15 gegen den an seiner Öffnungsvorsteuerseite 21 vom Vorsteuerdruck in der Vorsteuerleitung 12a abgeleiteten Druck in die gezeigte Schließstellung bringbar ist. Das Redundanz-Schaltglied A ist z.B. parallel zum Druckbegrenzungsventil 13 in dessen Leitungsstrang angeordnet.In addition to the two components (proportional magnets 4, 9) which can be actively actuated electrically, the two-way current controller R2 is assigned an electrically operable redundancy switching element A, which is energized when the proportional magnet 9 is energized. In the embodiment shown, this is a 2/2-way valve 14 in poppet design, ie with leak-free closed position, which can be brought by a black / white magnet 15 against the at its opening pilot 21 from the pilot pressure in the pilot line 12a derived pressure in the closed position shown , The redundancy switching element A is arranged for example parallel to the pressure relief valve 13 in the wiring harness.

Funktion:Function:

Vor Beginn der Senksteuerung wird der Lastdruck vom Druckregelventil 8 gehalten. Nun erhält der Proportionalmagnet 9 Strom, dessen Stärke mit der gewünschten Senkgeschwindigkeit korrespondiert. Gleichzeitig wird von einer nicht dargestellten übergeordneten Steuerung der Schwarz/Weiß-Magnet 15 bestromt, so dass das Redundanz-Schaltglied A seine Absperrstellung (wie gezeigt) einnimmt. Das Druckregelventil 8 lässt mit der Bestromung des Proportionalmagneten 9 über eine Messblendenöffnung Druckmittel abströmen, wobei die Druckwaage 10 die Druckdifferenz über die Messblendenöffnung und damit die Senkgeschwindigkeit konstant hält. Die Druckwaage 10 stellt sich in eine Position ein, die abhängt von den Vorsteuerdrücken in den Vorsteuerleitungen 11 und 12 und seiner Regelfeder (Lastunabhängigkeit).Before the lowering control starts, the load pressure is held by the pressure regulating valve 8. Now, the proportional solenoid 9 receives current whose strength corresponds to the desired lowering speed. At the same time, the black / white magnet 15 is energized by a higher-level control, not shown, so that the redundancy switching element A assumes its shut-off position (as shown). The pressure control valve 8 can flow with the energization of the proportional solenoid 9 via a metering orifice pressure medium, the pressure compensator 10 keeps the pressure difference across the orifice and thus the lowering speed constant. The pressure compensator 10 adjusts itself to a position which depends on the pilot control pressures in the pilot control lines 11 and 12 and its control spring (load independence).

Sollte beim Abbrechen der Senkbewegung aufgrund einer Verunreinigung oder eines mechanischen Schadens die Druckwaage 10 hängen bleiben, dann kann durch Entregen des Proportionalmagneten 9 das Druckregelventil 8 in seine Schließstellung gebracht werden, so dass der Hydraulikzylinder Z stehen bleibt. Die Störung der Druckwaage 10 ist damit ohne Belang. Sollte jedoch das Druckregelventil 8 selbst aufgrund einer Verunreinigung oder eines mechanischen Schadens hängen bleiben, und trotz Entregens des Proportionalmagneten 9 nicht in die Schließstellung kommen, dann würde der Hydraulikzylinder Z unter der Last weiter absinken, weil mit dem Proportionalmagneten 9 aktiv nicht mehr auf das Druckregelventil 8 eingewirkt werden kann und auch die Druckwaage 10 offen bleibt. In diesem Fall wird mit der Entregung des Proportionalmagneten 9 auch der Schwarz/Weiß-Magnet 15 des Redundanz-Schaltgliedes A entregt, so dass das Redundanz-Schaltglied A durch den Vorsteuerdruck in der Vorsteuerleitung 12a schlagartig in seine Öffnungsstellung geht und den Vorsteuerdruck zum Tank ablässt. Die Druckwaage 10 wird vom Vorsteuerdruck in der Vorsteuerleitung 11 in ihre Schließstellung gebracht und hält den Lastdruck. Der Hydraulikzylinder Z kommt zum Stillstand. Das Redundanz-Schaltglied A könnte im Falle eines Hängenbleibens der Druckwaage 10 auch einmal oder mehrfach bestromt und entregt werden, um die Druckwaage 10 wieder gängig zu machen.If, when canceling the lowering movement due to contamination or mechanical damage, the pressure compensator 10 remain stuck, then by de-energizing the proportional solenoid 9, the pressure control valve 8 can be brought into its closed position, so that the hydraulic cylinder Z stops. The disorder of the pressure compensator 10 is therefore irrelevant. However, should the pressure control valve 8 itself get stuck due to contamination or mechanical damage, and not come in the closed position despite de-energizing the proportional solenoid 9, then the hydraulic cylinder Z would continue to fall under the load, because active with the proportional solenoid 9 is no longer on the pressure control valve 8 can be acted on and the pressure compensator 10 remains open. In this case, the de-energization of the proportional solenoid 9 and the black / white magnet 15 of the redundancy switching element A is de-energized, so that the redundancy switching element A abruptly by the pilot pressure in the pilot line 12a in its open position and the pilot pressure to the tank , The pressure compensator 10 is brought from the pilot pressure in the pilot control line 11 in its closed position and holds the load pressure. The hydraulic cylinder Z comes to a stop. The redundancy switching element A could also be energized and de-energized once or several times in the event of the pressure compensator 10 getting stuck in order to make the pressure balance 10 common again.

In der elektrohydraulischen Hubsteuervorrichtung S in Fig. 2 ist das Redundanz-Schaltglied A dem Dreiwege-Stromregler R1 zur Hebesteuerung zugeordnet. D.h., das Redundanz-Schaltglied A ist in einer von der Vorsteuerleitung 6 zur Schließvorsteuerseite 20 der Druckwaage 5 abzweigenden Vorsteuerleitung 6a zum Tank enthalten und bietet eine Möglichkeit, im Fall einer Störung aktiv eingreifen zu können. Sollte beispielsweise die Druckwaage 5 aufgrund einer Störung in einer Mittelstellung hängen bleiben, so könnte ein weiteres Ausfahren des Hydraulikzylinders Z dadurch verhindert werden, dass das Druckregelventil 3 mittels des Proportionalmagneten 4 in seine Schließstellung gebracht wird. Wenn jedoch das Drucksteuerventil 3 hängen bleiben sollte, dann würde der Hydraulikzylinder Z allenfalls durch Abschalten des Motors M allmählich zum Anhalten gebracht werden können, jedoch dann nicht zuverlässig, wenn gleichzeitig andere Hydroverbraucher aus der Druckquelle mit versorgt werden müssen. In diesem Fall wird bei mit Entregen des Proportionalmagneten 4 ebenfalls entregtem Schwarz/Weiß-Magneten 15 das 2/2-Wege-Ventil 14 vom Vorsteuerdruck in der Vorsteuerleitung 6, 6a rasch in seine Öffnungsstellung gebracht, so dass der Vorsteuerdruck schlagartig zum Tank abgebaut wird und die Druckwaage 5 durch den im Hebestrang 1 herrschenden Druck über die Vorsteuerleitung 7 in die volle Öffnungsstellung gebracht wird, in der das Druckmittel aus dem Hebestrang 1 zum Tank abgeleitet und der Hydraulikzylinder Z zum Stillstand gebracht wird. Das Redundanz-Schaltglied A könnte bei mehrmaliger Bestromung und Entregung benutzt werden, die hängen gebliebene Druckwaage 5 wieder gängig zu machen.In the electro-hydraulic stroke control apparatus S in Fig. 2, the redundancy switching member A is assigned to the three-way current regulator R1 for lifting control. In other words, the redundancy switching element A is contained in a pilot line 6a branching off from the pilot line 6 to the closing pilot side 20 of the pressure compensator 5, and offers a possibility of being able to actively intervene in the event of a fault. For example, should the pressure compensator 5 become stuck due to a malfunction in a middle position, further extension of the hydraulic cylinder Z could be prevented by bringing the pressure control valve 3 into its closed position by means of the proportional magnet 4. However, if the pressure control valve 3 should hang, then the hydraulic cylinder Z would possibly be brought to a halt by switching off the motor M, but then not reliable, if at the same time other hydraulic consumers from the pressure source must be supplied with. In this case, with de-energizing the proportional solenoid 4 also de-energized black / white magnet 15, the 2/2-way valve 14 from the pilot pressure in the pilot line 6, 6a brought quickly into its open position, so that the pilot pressure is abruptly reduced to the tank and the pressure compensator 5 is brought by the prevailing pressure in the lifting strand 1 via the pilot line 7 in the full open position in which the pressure fluid from the lifting strand 1 derived to the tank and the hydraulic cylinder Z is brought to a standstill. The redundancy switching element A could be used in repeated energization and de-excitation to make the hanging pressure compensator 5 common again.

In Fig. 3 ist die elektrohydraulische Hubsteuervorrichtung S kombiniert mit Zusatzsteuerungen SH, SH' für weitere Hydroverbraucher des Flurförderfahrzeuges mit gemeinsamer Versorgung aus der Druckquelle P vorliegt. Die Steuerung SH dient beispielsweise zum Betätigen eines weiteren Hydroverbrauchers Z', beispielsweise eines Neigezylinders oder eines Greiferzylinders, der einen niedrigeren Versorgungsdruck braucht, als der Hydraulikzylinder Z. Die Versorgung der weiteren Hydroverbraucher Z' erfolgt über eine Druckleitung 1', die vom Hebestrang 1 stromauf des Druckregelventils 3 des Dreiwege-Stromreglers R1 abzweigt. Um auch in der Steuerung SH lastunabhängig zu arbeiten, wird der Lastdruck über eine Vorsteuerleitung 6b zur Vorsteuerleitung 6 und dann zur Schließvorsteuerseite 20 der Druckwaage 5 gebracht, und zwar über ein Wechselventil 16, das den jeweils höheren Steuerdruck an die Schließ-Vorsteuerseite 20 der Druckwaage 5 überträgt. Die Druckwaage 5 regelt den jeweils benötigten Druck ein.In Fig. 3, the electro-hydraulic stroke control device S is combined with additional controls SH, SH 'for more hydraulic consumers of the industrial truck with common supply from the pressure source P is present. The control SH is used, for example, to actuate a further hydraulic consumer Z ', for example a tilting cylinder or a gripper cylinder, which requires a lower supply pressure than the hydraulic cylinder Z. The supply of the further hydraulic consumer Z' via a pressure line 1 ', the upstream of the lifting strand 1 of the pressure control valve 3 of the three-way current regulator R1 branches off. In order to work independently of load in the control SH, the load pressure is brought via a pilot line 6b to the pilot line 6 and then the Schließvorsteuerseite 20 of the pressure compensator 5, via a shuttle valve 16, the respective higher control pressure to the Closing pilot side 20 of the pressure compensator 5 transmits. The pressure compensator 5 regulates the respectively required pressure.

Das Redundanz-Schaltglied A ist bei dieser Ausführungsform funktionell wechselweise sowohl dem Zweiwege-Stromregler R2 als auch dem Dreiwege-Stromregler R1 zugeordnet, und zwar über ein Wechselventil 17 (oder, wie in Fig. 4 und 5 gezeigt über zwei getrennte Vorsteuerleitungen). Von der Vorsteuerleitung 12 des Zweiwege-Stromreglers R2 zweigt eine Vorsteuerleitung 12' zum Wechselventil 17 ab. Zur anderen Seite des Wechselventils 17 führt eine Vorsteuerleitung 6', die von der Vorsteuerleitung 6 des Dreiwege-Stromreglers R1 abzweigt. Der jeweils höhere Vorsteuerdruck wird in die Vorsteuerleitung 18 übertragen, in der gegebenenfalls das Druckbegrenzungsventil 13 und das Redundanz-Schaltglied A angeordnet sind.The redundancy switch A in this embodiment is operatively associated alternately with both the two-way current regulator R2 and the three-way current regulator R1 via a shuttle valve 17 (or via two separate pilot lines, as shown in FIGS. 4 and 5). From the pilot control line 12 of the two-way flow controller R2 branches off a pilot line 12 'to the shuttle valve 17. To the other side of the shuttle valve 17 performs a pilot line 6 ', which branches off from the pilot line 6 of the three-way current regulator R1. The respective higher pilot pressure is transmitted to the pilot line 18, in which optionally the pressure relief valve 13 and the redundancy switching element A are arranged.

Das Redundanz-Schaltglied A ist in Fig. 3 ein 2/2-Wege-Proportionaldruckregelventil 14', das durch den Vorsteuerdruck in der Vorsteuerleitung 18 in Öffnungsrichtung an seiner Öffnungsvorsteuerseite 21 beaufschlagt wird, und sich durch einen Proportionalmagneten 15' in Richtung zur gezeigten Schließstellung verstellen lässt.The redundancy switching element A is in Fig. 3, a 2/2-way proportional pressure control valve 14 ', which is acted upon by the pilot pressure in the pilot line 18 in the opening direction at its Öffnungsvorsteuerseite 21, and by a proportional solenoid 15' in the direction of the closed position shown can be adjusted.

Die Bestromung des Proportionalmagneten 15' erfolgt bei der Hebesteuerung gleichzeitig mit der Bestromung des Proportionalmagneten 4, hingegen bei der Senksteuerung gleichzeitig mit der Bestromung des Proportionalmagneten 9. Mit dem Proportionalmagneten 15' lässt sich nicht nur die Schließstellung des Redundanz-Schaltglieds A einstellen, sondern lassen sich gegebenenfalls abhängig von einer schwächeren Bestromung bei alleiniger oder zusätzlicher Betätigung des Hydraulikzylinders Z' Zwischenstellungen einstellen, um den Vorsteuerdruck in der Vorsteuerleitung 18 für die Druckwaage 5 zu senken. So erfüllt das Redundanz-Schaltglied die Funktion eines elektrisch verstellbaren Druckbegrenzungsventils zum Einstellen des Vorsteuerdrucks an der Schließ-Vorsteuerseite 20 der Druckwaage 5, z.B. um für den weiteren Hydroverbraucher Z' einen niedrigeren Versorgungsdruck einzustellen. Es könnte das Redundanz-Schaltglied A mit dieser Auslegung auch zum gewollten Reduzieren des Vorsteuerdruck-Niveaus für die Hebe- und/oder Senksteuerung benutzt werden.The energization of the proportional magnet 15 'takes place simultaneously with the energization of the proportional magnet 4 in the lifting control, while in the lowering control simultaneously with the energization of the proportional magnet 9. The proportional solenoid 15' can not only set the closed position of the redundancy switching element A, but let Optionally, depending on a weaker energization with sole or additional actuation of the hydraulic cylinder Z 'set intermediate positions to lower the pilot pressure in the pilot line 18 for the pressure compensator 5. Thus, the redundancy switching element fulfills the function of an electrically adjustable pressure relief valve for adjusting the pilot pressure at the closing pilot side 20 of the pressure compensator 5, eg to set a lower supply pressure for the further hydraulic consumer Z '. The redundancy switch A of this design could also be used for intentionally reducing the pilot pressure level for the lift and / or lower control.

Funktion:Function:

Bei der Hebesteuerung ist das Wechselventil 17 in seiner linken Stellung, so dass in der Vorsteuerleitung 18 der Vorsteuerdruck aus der Vorsteuerleitung 6 herrscht. Sollte das Druckregelventil 3 hängen bleiben, obwohl der Proportionalmagnet 4 entregt ist, ist auch der Proportionalmagnet 15' entregt, so dass das Redundanz-Schaltglied A über den Vorsteuerdruck in der Vorsteuerleitung 18 schlagartig seine Öffnungsstellung einnimmt und den Vorsteuerdruck zum Tank abbaut. Die Druckwaage 5 geht schlagartig in ihre Öffnungsstellung, in der das Druckmittel direkt zum Tank abgeleitet wird und der Hydraulikzylinder Z seine Ausfahrbewegung abbricht, wobei der Lastdruck von einem Rückschlagventil stromab des Druckregelventils 3 und dem Druckregelventil 8 gehalten wird. Gegebenenfalls wird der Proportionalmagnet 15' dann aber nur nach einer Programmroutine entregt, bei der festgestellt wird, dass der Hubzylinder Z nicht ordnungsgemäß angehalten hat.In the lift control, the shuttle valve 17 is in its left position, so that prevails in the pilot line 18, the pilot pressure from the pilot line 6. If the pressure control valve 3 get stuck, although the proportional solenoid 4 is de-energized, the proportional solenoid 15 'is de-energized, so that the redundancy switching element A via the pilot pressure in the pilot line 18 abruptly assumes its open position and degrades the pilot pressure to the tank. The pressure compensator 5 is abruptly in its open position in which the pressure medium is discharged directly to the tank and the hydraulic cylinder Z stops its extension movement, wherein the load pressure of a check valve downstream of the pressure control valve 3 and the pressure control valve 8 is maintained. Optionally, the proportional solenoid 15 'but then de-energized only after a program routine in which it is determined that the lifting cylinder Z has not stopped properly.

Bei der Senksteuerung nimmt das Wechselventil 17 die gezeigte Position ein, so dass in der Vorsteuerleitung 18 der Druck der Vorsteuerleitung 12 bzw. 12' herrscht. Sollte das Druckregelventil 8 hängen bleiben, dann wird, wie eingangs erläutert, über das in seine Öffnungsstellung gehende Redundanz-Schaltglied A die Druckwaage 10 in ihre Schließstellung gebracht und so der Lastdruck des Hydraulikzylinders Z gehalten.In the lowering control, the shuttle valve 17 assumes the position shown, so that in the pilot line 18, the pressure of the pilot line 12 and 12 'prevails. If the pressure control valve 8 get stuck, then, as explained above, via the going into its open position redundancy switching element A, the pressure compensator 10 is brought into its closed position and held the load pressure of the hydraulic cylinder Z.

Um bei Betätigung des Hydroverbrauchers Z' einen niedrigeren Versorgungsdruck einzustellen, wird von der übergeordneten elektronischen Steuerung CU, die zweckmäßigerweise einen Mikroprozessor oder eine anderen Logikschaltung enthält, der Proportionalmagnet 15' nur so stark bestromt, dass das Druckregelventil 14' eine Zwischenstellung einnimmt und regelnd einen Teil des Druckmittels aus der Vorsteuerdruckleitung 18 zum Tank ablässt, um den Vorsteuerdruck an der Schließ-Vorsteuerseite 20 der Druckwaage 5 zu verringern, so dass die Druckwaage 20 nun relativ mehr Druckmittel zum Tank steuert und den Versorgungsdruck in der Druckleitung 1' vermindert.In order to set a lower supply pressure upon actuation of the hydraulic consumer Z ', the proportional electronic control unit 15' is supplied with current only to such an extent by the superordinate electronic controller CU, which expediently contains a microprocessor or another logic circuit, that the pressure regulating valve 14 'assumes an intermediate position and regulates one Part of the pressure medium from the pilot pressure line 18 to the tank discharges to reduce the pilot pressure at the closing pilot side 20 of the pressure compensator 5, so that the pressure compensator 20 now controls relatively more pressure fluid to the tank and reduces the supply pressure in the pressure line 1 '.

Um sicherzustellen, dass bei in die Öffnungsstellung verstelltem Redundanz-Schaltglied A nach Abbrechen der Senksteuerung bei hängen gebliebenem Proportional-Druckregelventil 8 keine ganz langsame Senkbewegung des Hydraulikzylinders Z erfolgt, ist in den Fig. 4 und 5 jeweils ein Redundanz-Schaltglied A vorgesehen, das bei entregtem Schaltmagneten 15 oder Proportionalmagneten 15' die Vorsteuerleitung 12 zum Senkzweig 2 absperrt und die Öffnungs-Vorsteuerseite 19 der Druckwaage 10 über eine Vorsteuerleitung 12b direkt zum Tank entlastet.To ensure that in the open position displaced redundancy switch A after canceling the lowering control with stuck proportional pressure control valve 8 is not a very slow lowering of the hydraulic cylinder Z takes place, in Figs. 4 and 5 each have a redundancy switching element A is provided with de-energized solenoid 15 or proportional solenoid 15 ', the pilot line 12 to Senkzweig 2 shuts off and the opening pilot side 19 of the pressure compensator 10 relieved via a pilot line 12b directly to the tank.

In Fig. 4 ist das Redundanz-Schaltglied A ein 4/2-Wegeschaltventil 14" mit einem Schaltmagneten 15 als Aktuator gegen eine Feder 26. Das Redundanz-Schaltglied A dient hier nicht zum Einstellen eines niedrigeren Versorgungsdruckes für weitere Hydraulikverbraucher, sondern zur Absicherung der Stromregler R1, R2 im Falle einer Störung und gegebenenfalls zum willkürlichen Freischalten der jeweiligen Druckwaage aus anderen Gründen, z.B. zwecks einer individuellen Abbremsung oder aus anderen sicherheitsbedingten Gründen.In Fig. 4, the redundancy switching element A is a 4/2-way switching valve 14 "with a solenoid 15 as an actuator against a spring 26. The redundancy switching element A is not used here to set a lower supply pressure for other hydraulic consumers, but to hedge the Current controller R1, R2 in case of failure and possibly for arbitrary release of the respective pressure compensator for other reasons, eg for the purpose of individual braking or for other safety-related reasons.

Das 4/2-Wegeschaltventil 14" ist ein Schieberventil mit einem Ventilschieber 27, der bezüglich des Tankdrucks druckausgeglichen ist. Das Schaltventil 14" ist zwischen den beiden Vorsteuerleitungen 12 (vom Senkstrang 2) und 6a (von der Schließ-Vorsteuerseite 20) der Druckwaage 5 und gegebenenfalls dem Wechselventil 16 sowie dem Tank T und der Vorsteuerleitung 12b zur Öffnungs-Vorsteuerseite 19 der Druckwaage 10 angeordnet. Bei entregtem Schaltmagneten 15 (dies kann ein einfacher Schwarz/Weiß-Schaltmagnet sein) liegt die gezeigte Schaltstellung vor, in der die Vorsteuerleitungen 12, 12b voneinander getrennt und die Vorsteuerleitungen 6a und 12b gemeinsam in einer Überbrückung 24 im Ventilschieber 27 zum Tank T entlastet sind. Bei erregtem Schaltmagneten 15 wird eine Schaltstellung eingestellt, in der die Vorsteuerleitung 6a vom Tank T getrennt und die Vorsteuerleitungen 12, 12b miteinander verbunden sind.The 4/2-way switching valve 14 "is a spool valve having a spool 27 which is pressure balanced with respect to tank pressure." The switching valve 14 "is between the two pilot lines 12 (from the drawstring 2) and 6a (from the closing pilot side 20) of the pressure compensator 5 and optionally the shuttle valve 16 and the tank T and the pilot control line 12b to the opening pilot side 19 of the pressure compensator 10 are arranged. With de-energized solenoid 15 (this may be a simple black and white solenoid) is the switching position shown in which the pilot lines 12, 12b separated from each other and the pilot lines 6a and 12b are relieved together in a bypass 24 in the valve spool 27 to the tank T. , When energized solenoid 15, a switching position is set in which the pilot line 6a separated from the tank T and the pilot lines 12, 12b are connected to each other.

Sollte das Proportional-Druckregelventil 8 beim Abbrechen der Senksteuerung hängen bleiben, dann wird in der gezeigten Schaltstellung die Öffnungs-Vorsteuerseite 19 der Druckwaage 10 zum Tank entlastet, so dass die Druckwaage 10 in ihre Schließstellung geht und die Last hält. Der Hydraulikzylinder bleibt stehen. Die Funktion bei der Hebesteuerung ist gleich wie anhand Fig. 2 erläutert.If the proportional pressure control valve 8 get stuck when canceling the lowering control, then the opening pilot side 19 of the pressure compensator 10 is relieved to the tank in the switching position shown, so that the pressure compensator 10 goes into its closed position and holds the load. The hydraulic cylinder stops. The function in the lift control is the same as explained with reference to FIG.

Strichpunktiert ist eine Nutzsenkleitung 2a gezeigt, die zwischen dem Proportional-Druckregelventil 8 und der Druckwaage 10 vom Senkstrang 2 abzweigt und an die Saugseite der Pumpe P angeschlossen ist. Zwischen dem Anschluss der Nutzsenkleitung 2a und dem Tank ist ein Rückschlagventil V angedeutet, das in Richtung zum Tank sperrt, um beim Nutzsenken das ausgeschobene Druckmittel durch die Pumpe P zu fördern und diese als Motor für den dann als Generator arbeitenden Elektromotor zur Energierückgewinnung anzutreiben. Das Druckmittel strömt dann über die Druckwaage 20 zum Tank, oder, falls weitere Hydraulikverbraucher angeschlossen und versorgt werden, weiter. Falls eine drehzahlregelbare Pumpe P verwendet wird, wird beim Nutzsenken die Druckwaage 10 im Falle der Zuschaltung weiterer Hydraulikverbraucher die jeweils gerade erforderliche Menge durch die Pumpe P einstellen. Die Option der Nutzsenkung lässt sich problemlos bei jeder gezeigten Ausführungsform integrieren.Dash-dotted lines a Nutzsenkleitung 2 a is shown, which branches off between the proportional pressure control valve 8 and the pressure compensator 10 from the Senkstrang 2 and is connected to the suction side of the pump P. Between the connection of the Nutzsenkleitung 2a and the tank, a check valve V is indicated, which blocks in the direction of the tank to promote the lowering of the pressure medium by the pump P and to drive this as a motor for the then working as a generator electric motor for energy recovery at Nutzsenken. The pressure medium then flows via the pressure compensator 20 to the tank, or, if further hydraulic consumers are connected and supplied, on. If a speed-controllable pump P is used, the pressure compensator 10 is set in the case of the connection of further hydraulic consumers the amount just required each time by the pump P. The pay reduction option can be easily integrated into any embodiment shown.

In Fig. 5 ist das Redundanz-Schaltglied A ein 4/3-Proportional-Druckregelventil 14"' mit dem Proportionalmagneten 15' als Aktuator des Ventilschiebers 27' gegen die Kraft einer Feder 26 und den Vorsteuerdruck in einer Vorsteuerleitung 6c, die von der Vorsteuerleitung 6a abzweigt. Die weitere Verschaltung entspricht der in Fig. 4 gezeigten und bereits erläuterten. Der Ventilschieber 27' ist bezüglich des Tankdrucks über die Vorsteuerleitung 25 druckausgeglichen, zweckmäßigerweise vollflächig, während der Vorsteuerdruck aus der Vorsteuerleitung 6c zweckmäßig nur einen Teilbereich der Fläche des Ventilschiebers 27 gegen den Proportionalmagneten 15' beaufschlagt, um einen schwachen und kompakten bzw. kostengünstigen Proportionalmagneten 15' verwenden zu können.In Fig. 5, the redundancy switching element A is a 4/3-proportional pressure regulating valve 14 "'with the proportional solenoid 15' as an actuator of the valve spool 27 'against the force of a spring 26 and the pilot pressure in a pilot line 6c, that of the pilot control line The further connection corresponds to that already shown in Fig. 4. The valve spool 27 'is pressure-balanced with respect to the tank pressure via the pilot control line 25, expediently over the full area, while the pilot pressure from the pilot control line 6c expediently only a partial area of the surface of the valve spool 27 acted upon the proportional solenoid 15 'in order to use a weak and compact or inexpensive proportional magnet 15' can.

Zum Verringern des Vorsteuerdrucks an der Schließ-Vorsteuerseite 20 der Druckwaage 5 bei der Hebesteuerung oder beim Steuern weiterer Hydraulikverbraucher zwecks Verringerung deren Versorgungsdrucks wird z.B. der Proportionalmagnet 15' nach Maßgabe des gewünschten Vorsteuerdrucks in der Vorsteuerleitung 6a schwächer bestromt als bei der Absicherung des jeweiligen Stromreglers, um zwischen Endstellungen mit deutlicher Überdeckung regelnde Zwischenschaltstellungen einzunehmen, in denen sowohl die Vorsteuerleitungen 12, 12b miteinander verbunden sind und auch die Vorsteuerleitung 6a direkt mit dem Tank verbunden ist.For reducing the pilot pressure at the closing pilot side 20 of the pressure compensator 5 in the lift control or in controlling further hydraulic consumers to reduce their supply pressure, e.g. the proportional solenoid 15 'in accordance with the desired pilot pressure in the pilot line 6a energized weaker than in the protection of the respective current regulator to take between end positions with significant coverage regulating intermediate switch positions in which both the pilot lines 12, 12b are connected to each other and the pilot line 6a directly connected to the tank.

Claims (14)

  1. An electrohydraulic lifting control device (S) for industrial trucks, in particular for stacker trucks, comprising a lifting branch (1) provided between a pressure source (P) and a hydraulic cylinder (Z) and including a three-way flow regulator (R1), which is provided with a proportional magnet and a pressure balance (5) and which is adapted to be electrically operable at least for the purpose of lifting control, and further comprising a lowering branch (2) branching off from the lifting branch (1) towards the reservoir and including, for the purpose of lowering control, an electrically operable two-way flow regulator (R2) provided with a proportional magnet and a pressure balance (10) characterised in that a redundancy switching element (A), which is actively electrically operable between closed and open positions, is provided between the pilot pressure circuit of the two-way flow regulator (R2) and/or the pilot pressure circuit of the three-way flow regulator (R1) and the reservoir (T).
  2. An electrohydraulic lifting control device according to claim 1, characterised in that the redundancy switching element (A) is arranged between the reservoir (T) and an opening pilot side (19) of the pressure balance (10) of the two-way flow regulator (R2) and/or a closing pilot side (20) of the pressure balance (5) of the three-way flow regulator (R1).
  3. An electrohydraulic lifting control device according to claim 1, characterised in that the redundancy switching element (A) is a 2/2 way regulating control valve (14') with pilot pressure control (21) in opening direction and with a proportional magnet (15') as an actuator for the closing direction.
  4. An electrohydraulic lifting control device according to claim 1, characterised in that the redundancy switching element (A) is a 2/2-way control valve (14) with pilot pressure control (21) in opening direction and with a black-and-white switching magnet (15') as an actuator for the closing direction.
  5. An electrohydraulic lifting control device according to claim 3 or 4, characterised in that the pilot pressure control (21) of the redundancy switching element (A) is connected to the opening pilot side (19) of the pressure balance (10) of the two-way flow regulator (R2) or the closing pilot side (20) of the pressure balance (5) of the three-way flow regulator (R1).
  6. An electrohydraulic lifting control device according to claim 5, characterised in that the pilot pressure control (21) of the redundancy switching element (A) is adapted to be connected in a pressure-dependent manner via a change-over valve (17) either to the opening pilot side (19) of the pressure balance (10) of the two-way flow regulator (R2) or to the closing side (20) of the pressure balance (5) of the three-way flow regulator (R1).
  7. An electrohydraulic lifting control device according to claim 2, characterised in that the pressure balance (5) of the three-way flow regulator (R1) additionally is adapted for a load-independent control of at least one additional hydroconsumer (Z') which is supplied from the same pressure source (P), and that the redundancy switching element (A) and the pressure balance (5) of the three-way flow regulator (R1) are adapted to be used for adjusting a supply pressure for said additional hydroconsumer (Z') which is at least lower than the supply pressure adjusted for the lifting control of the hydraulic cylinder (Z).
  8. An electrohydraulic lifting control device according to claim 2, characterised in that the redundancy switching element (A) is a 4/2-way switching valve (14"), which is inserted between separate pilot lines (12, 6a) leading to the lowering branch (2) and the closing pilot side (20) of the pressure balance (5) of the three-way flow regulator (R1) and to the reservoir (T) and a pilot line (12b) leading to the opening pilot side (19) of the pressure balance (10) of the two-way flow regulator (R2), and which valve (14") is provided with a black-and-white switching magnet (15) as an actuator for one switching direction, and which, in one switching position, separates the pilot line (6a) from the reservoir (T) and interconnects the pilot lines (12, 12b) and in another switching position, separates the pilot lines (12, 12b) and connects the pilot lines (6a, 12b) to the reservoir.
  9. An electrohydraulic lifting control device according to claims 2 and 7, characterised in that the redundancy switching element is a 4/3-way proportional pressure regulating control valve (14"'), which is inserted between separate pilot lines (12, 6a) leading to the lowering branch (2) and to the closing pilot side (20) of the pressure balance (5) of the three-way flow regulator (R1) and the reservoir (T) and a pilot line (12b) leading to the opening pilot side (19) of the pressure balance (10) of the two-way flow regulator (R2), and which valve (14"') is provided with a proportional magnet (15') as an actuator for one switching direction counter to the both the force of the spring (26) an the pilot pressure in the pilot line (6a), and which, in one final switching position, separates the pilot line (6a) from the reservoir and interconnects the pilot lines (12, 12b) and in another final switching position, separates the pilot lines (12, 12b) and connects the pilot lines (6a, 12b) to the reservoir (T), and which, in variable intermediate switching positions between said end switching positions as adjusted by the pilot pressure and varied by the value of the current supplied to the proportional magnet in pilot line (6a) interconnects the pilot lines (12, 12b) and connects the pilot line (6a) to the reservoir (T).
  10. An electrohydraulic lifting control device according to claim 8 or 9, characterised in that the 4/2-way switching valve (14") or the 4/3-way proportional pressure regulating control valve (14"') is a slider valve whose leakproofness satisfies the requirements for industrial trucks.
  11. An electrohydraulic lifting control device according to claim 8, characterised in that the 4/2-way switching valve (14") comprises a valve slide member (27) which is pressure-compensated at both ends at large pressure receiving areas to the reservoir (T).
  12. An electrohydraulic lifting control device according to claim 9, characterised in that the 4/3-way proportional pressure control valve (14"') comprises a valve slide member (27) which is pressure-compensated at both ends on full pressure receiving areas to the reservoir (T) while only a part of the full pressure receiving rea of the said valve slide member (27) is acted upon by the pilot pressure in the pilot line (6a) counter to the proportional magnet (15').
  13. An electrohydraulic lifting control device according to at least one of the claims 1 to 12, characterised in that the pressure source (B) comprises a speed-controlled pump having an electric motor (M) which is adapted to be operated by the pump as a generator for recovering energy during load lowering control, that a check valve (V) blocking towards the reservoir (T) is provided between the pump and the reservoir (T), and that a recovering lowering line (2a) branching off from the lowering branch (2) at a point upstream of the pressure balance (10) of the two-way flow regulator (R2) is connected to the pump at a point downstream of the check valve (V).
  14. An electrohydraulic lifting control device according to at least one of the preceding claims, characterised in that the electrically actively operable components, (4, 9, 15, 15', M) of the lifting control device (S) are connected to an electronic control unit (SU) comprising a microprocessor or a logic circuit.
EP03002659.5A 2002-06-03 2003-02-11 Electro-hydraulic lifting control device for industrial use vehicles Expired - Fee Related EP1369598B2 (en)

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DE20208577U DE20208577U1 (en) 2002-06-03 2002-06-03 Electro-hydraulic lift control device for industrial trucks
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EP1369598B1 true EP1369598B1 (en) 2007-09-26
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Also Published As

Publication number Publication date
JP3785159B2 (en) 2006-06-14
US20030221548A1 (en) 2003-12-04
EP1369598B2 (en) 2015-08-19
EP1369598A1 (en) 2003-12-10
US6837045B2 (en) 2005-01-04
DE50308262D1 (en) 2007-11-08
DE20208577U1 (en) 2003-12-11
JP2004044795A (en) 2004-02-12

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