EP0574737A1 - Véhicule à propulsion électrique à alimentation par accumulateurs, en particulier Chariot-élévateur - Google Patents

Véhicule à propulsion électrique à alimentation par accumulateurs, en particulier Chariot-élévateur Download PDF

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Publication number
EP0574737A1
EP0574737A1 EP93108385A EP93108385A EP0574737A1 EP 0574737 A1 EP0574737 A1 EP 0574737A1 EP 93108385 A EP93108385 A EP 93108385A EP 93108385 A EP93108385 A EP 93108385A EP 0574737 A1 EP0574737 A1 EP 0574737A1
Authority
EP
European Patent Office
Prior art keywords
pump
pressure
control valve
differential pressure
control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP93108385A
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German (de)
English (en)
Other versions
EP0574737B1 (fr
Inventor
Peter Dipl.-Ing. Dibbern (Fh)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jungheinrich AG
Original Assignee
Jungheinrich AG
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Filing date
Publication date
Application filed by Jungheinrich AG filed Critical Jungheinrich AG
Publication of EP0574737A1 publication Critical patent/EP0574737A1/fr
Application granted granted Critical
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Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/22—Hydraulic devices or systems

Definitions

  • the invention relates to a vehicle with a battery-electric traction drive, in particular a loader, according to the preamble of claim 1.
  • the battery feeds both the travel drive and the drive for at least one hydraulic pump that supplies the hydraulic systems.
  • this can also include a power steering assist device.
  • a hydraulic consumer is usually supplied from the pump via a directional valve, via which the volume flow flowing to the consumer is set.
  • the pump is to be driven so that a desired volume flow is actually achieved. If no special control is provided, the pump must be operated at maximum speed or maximum output. However, if the directional control valve is only partially open, considerable throttling losses occur. For secondary functions, i.e. with smaller hydraulic consumers, the throttling losses are very high due to the very low delivery rate required.
  • a load sensing signal corresponds to the pressure e.g. behind the steering valve or the directional control valve, which in turn is manually operated and represents the operator's requirement for the hydraulic system.
  • EP-A-0 251 290 has also disclosed a Signal, based on a hydraulic steering device, which is dependent on the pressure carried in a control signal line behind the steering valve, to give a signal to the pulse control of an electric motor that drives the pump.
  • Electric motors for the traction drive and / or the hydraulic pump are usually direct current motors which are controlled via a pulsed operation.
  • a good speed control can be carried out with the aid of the pulse control.
  • a constant feed pump can therefore be used to regulate the volume flow, the volume flow then being dependent on the engine speed.
  • the invention has for its object to provide a vehicle with battery-electric traction drive, in particular rear loader, in which the efficiency of the working hydraulic circuit is improved.
  • the delivery rate is adjusted to the required volume flow. Throttle losses do not occur because disturbance variables are also recorded.
  • the pressure adjusts to the pressure of the consumer plus the pressure loss. This is done according to the invention in that a pressure difference is determined from the outlet pressure of the pump and the pressure behind the control valve. This differential pressure, which is measured with the help of a suitable sensor, is converted into an actual value signal, which together is given to a controller with a predetermined setpoint. The control signal from the controller is then switched to pulse control. For a given setting of the valve, the pressure difference depends on the volume flow coming from the pump. If this is low, the pressure difference is also small and a relatively high control deviation arises in the controller, which has the consequence that the speed of the pump motor is increased via the pulse control.
  • the invention provides a control system that controls the pump only on the power that is actually queried. Excess output is no longer generated. Losses only occur as pressure losses in the lines and the valves. The invention thus enables the operation of a hydraulic system with optimal efficiency.
  • a pressure compensator is preferably assigned to the valve, which responds whenever the pump pressure is too high compared to the load pressure. This can be done, for example, by suddenly closing the directional control valve because of the pump speed cannot be reduced quickly enough.
  • a movable element acted upon by both pressures is provided, the position of which is detected and converted into an electrical differential pressure signal.
  • the movable element can e.g. be a piston which is held in a neutral position in a cylinder by means of springs. It is also possible to provide a membrane or the like which is pressurized from both sides.
  • the embodiment described below relates a battery-operated lift truck, the mast of which has at least one lift cylinder. It is designated by 10 in FIG. 3. It is used to lift a load, represented by arrow 12, for example with the aid of a suitable load handler. For example, a load is stacked on a shelf or removed from the shelf.
  • the hydraulic cylinder is supplied by a motor pump unit 14, which consists of a pulse-controlled direct current motor and a constant feed pump. Such units are known.
  • the impulse control is represented by block 16.
  • a control valve 18 is connected between the pump 14 and the lifting cylinder 10 and can be actuated, for example, by means of a hand lever on the lift truck. This is indicated by the arrow 20.
  • Fig. 1 the pressure is plotted against the delivery rate of the hydraulic pump. Due to losses in lines and valves, a reduced pressure p load occurs on the load, for example the hydraulic cylinder 10. The delivery rate actually required corresponds to Q erf . Since the disturbances such as load pressure, friction, etc. can not be readily detect the flow rate Q is control selected higher than the required flow rate Q erf. There is therefore a more or less large area in which throttle losses occur. They are only minimized when the valve 18 is fully open and the pump delivers with a maximum delivery rate Q max .
  • a differential pressure meter 22 is provided, which is connected to the outlet of the pump 14 and to the line behind the valve 18.
  • the pressure meter 22 which has, for example, a differential pressure piston or a differential pressure membrane, the displacement of the piston or the membrane being converted into an electrical signal, measures the pressure drop across the more or less open valve 18.
  • the differential pressure is compared with a setpoint 24, according to which a controller 26 outputs a control signal to the pulse controller 16 in accordance with the control deviation.
  • the setpoint is constant and corresponds, for example, to the pressure difference of the valve when the position is fully open and the maximum pump volume flow. It can be seen that the delivery rate of the pump 14 is adjusted to the required volume flow Q erf . Throttle losses do not arise because the disturbance variables are also recorded.
  • the pump pressure adjusts itself to the load pressure plus the pressure losses. In the control described, the delivery rate requested by the valve position is a system parameter. A change in the valve position is treated like a disturbance variable.

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Structural Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Civil Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Operation Control Of Excavators (AREA)
EP93108385A 1992-06-17 1993-05-25 Véhicule à propulsion électrique à alimentation par accumulateurs, en particulier Chariot-élévateur Expired - Lifetime EP0574737B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4219787 1992-06-17
DE4219787A DE4219787C1 (de) 1992-06-17 1992-06-17 Fahrzeug mit batterie-elektrischem Fahr-Antrieb, insbesondere Hublader

Publications (2)

Publication Number Publication Date
EP0574737A1 true EP0574737A1 (fr) 1993-12-22
EP0574737B1 EP0574737B1 (fr) 1996-09-04

Family

ID=6461187

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93108385A Expired - Lifetime EP0574737B1 (fr) 1992-06-17 1993-05-25 Véhicule à propulsion électrique à alimentation par accumulateurs, en particulier Chariot-élévateur

Country Status (2)

Country Link
EP (1) EP0574737B1 (fr)
DE (2) DE4219787C1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0669281A1 (fr) * 1994-01-29 1995-08-30 Jungheinrich Aktiengesellschaft Dispositif de levage hydraulique pour chariots de manutention actionnés par batterie

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19612582A1 (de) * 1996-03-29 1997-10-02 Miag Fahrzeugbau Gmbh Antriebseinheit für ein Fahrzeug
DE19744429A1 (de) * 1997-10-08 1999-04-22 Still Wagner Gmbh & Co Kg Flurförderfahrzeug mit einer Lastaufnahmevorrichtung und Verfahren zum Absenken der Lastaufnahmevorrichtung
DE10033223A1 (de) * 2000-07-07 2002-01-17 Dambach Lagersysteme Gmbh Verfahren zur Steuerung einer hydraulischen Antriebseinheit in einem Regalbediengerät

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0190703A1 (fr) * 1985-02-04 1986-08-13 Hitachi Construction Machinery Co., Ltd. Système de commande pour un circuit hydraulique
EP0379595A1 (fr) * 1988-07-08 1990-08-01 Hitachi Construction Machinery Co., Ltd. Appareil hydrodynamique
DE4026695A1 (de) * 1989-08-25 1991-03-14 Toyoda Automatic Loom Works Hydraulikfluid-durchflusssteuervorrichtung fuer industrie-fahrzeuge
DE4036860A1 (de) * 1989-11-20 1991-07-04 Toyoda Automatic Loom Works Belastung-/entlastung-steuervorrichtung fuer einen hydraulikkreis
EP0462589A2 (fr) * 1990-06-19 1991-12-27 Hitachi Construction Machinery Co., Ltd. Système de commande pour un entraînement hydraulique indépendamment de la charge
WO1992010684A1 (fr) * 1990-12-15 1992-06-25 Barmag Ag Systeme hydraulique
WO1992014944A1 (fr) * 1991-02-15 1992-09-03 Caterpillar Inc. Circuit hydraulique et systeme de commande associe

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3270266D1 (en) * 1981-08-10 1986-05-07 Clark Equipment Co Vehicle and hydraulic system with single pump therefor
DE3622218A1 (de) * 1986-07-02 1988-01-14 Still Gmbh Kraftfahrzeug, vorzugsweise flurfoerderzeug, mit einer hydraulischen arbeitseinrichtung und mit einer hydraulischen lenkhilfskraftunterstuetzungseinrichtung

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0190703A1 (fr) * 1985-02-04 1986-08-13 Hitachi Construction Machinery Co., Ltd. Système de commande pour un circuit hydraulique
EP0379595A1 (fr) * 1988-07-08 1990-08-01 Hitachi Construction Machinery Co., Ltd. Appareil hydrodynamique
DE4026695A1 (de) * 1989-08-25 1991-03-14 Toyoda Automatic Loom Works Hydraulikfluid-durchflusssteuervorrichtung fuer industrie-fahrzeuge
DE4036860A1 (de) * 1989-11-20 1991-07-04 Toyoda Automatic Loom Works Belastung-/entlastung-steuervorrichtung fuer einen hydraulikkreis
EP0462589A2 (fr) * 1990-06-19 1991-12-27 Hitachi Construction Machinery Co., Ltd. Système de commande pour un entraînement hydraulique indépendamment de la charge
WO1992010684A1 (fr) * 1990-12-15 1992-06-25 Barmag Ag Systeme hydraulique
WO1992014944A1 (fr) * 1991-02-15 1992-09-03 Caterpillar Inc. Circuit hydraulique et systeme de commande associe

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0669281A1 (fr) * 1994-01-29 1995-08-30 Jungheinrich Aktiengesellschaft Dispositif de levage hydraulique pour chariots de manutention actionnés par batterie

Also Published As

Publication number Publication date
DE4219787C1 (de) 1994-01-05
EP0574737B1 (fr) 1996-09-04
DE59303622D1 (de) 1996-10-10

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