EP0872446B1 - Installation hydraulique pour chariot élévateur à fourche - Google Patents

Installation hydraulique pour chariot élévateur à fourche Download PDF

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Publication number
EP0872446B1
EP0872446B1 EP98107020A EP98107020A EP0872446B1 EP 0872446 B1 EP0872446 B1 EP 0872446B1 EP 98107020 A EP98107020 A EP 98107020A EP 98107020 A EP98107020 A EP 98107020A EP 0872446 B1 EP0872446 B1 EP 0872446B1
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EP
European Patent Office
Prior art keywords
valve
pressure
drive
piston
control valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP98107020A
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German (de)
English (en)
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EP0872446A3 (fr
EP0872446A2 (fr
Inventor
Eckehart Schulze
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Voith Turbo H and L Hydraulic GmbH and Co KG
Original Assignee
Hartmann and Lammle GmbH and Co KG
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Publication of EP0872446A2 publication Critical patent/EP0872446A2/fr
Publication of EP0872446A3 publication Critical patent/EP0872446A3/fr
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Publication of EP0872446B1 publication Critical patent/EP0872446B1/fr
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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
    • 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
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/05—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed specially adapted to maintain constant speed, e.g. pressure-compensated, load-responsive
    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/01—Locking-valves or other detent i.e. load-holding devices
    • F15B13/015—Locking-valves or other detent i.e. load-holding devices using an enclosed pilot flow valve
    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/044—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by electrically-controlled means, e.g. solenoids, torque-motors
    • 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
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • 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
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional 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
    • F15B2211/30—Directional control
    • F15B2211/35—Directional control combined with flow control
    • F15B2211/351—Flow control by regulating means in feed line, i.e. meter-in control
    • 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
    • F15B2211/35—Directional control combined with flow control
    • F15B2211/353—Flow control by regulating means in return line, i.e. meter-out control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6654—Flow rate control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/76—Control of force or torque of the output member
    • F15B2211/761—Control of a negative load, i.e. of a load generating hydraulic energy

Definitions

  • the invention relates to a hydraulic installation on one Forklift truck with a hydraulic lift drive for a lift, with another hydraulic drive as a tilt actuator as well as with these hydraulic drives individually assigned valve arrangements, by means of those for the different movements of the lift required operating pressures and pressure medium flow rates are controllable, and with the further in the preamble of claim 1, generic Features.
  • a hydraulic installation on one Forklift vehicle is known from EP 498610 A.
  • the linear actuator by means of whose masses can be raised and lowered must be, which can be up to a few t designed as a single-acting hydraulic cylinder, its lifting operation through valve-controlled pressure medium inflow to Drive pressure chamber and its lowering operation through valve-controlled Outflow of pressure medium from the drive pressure chamber the hydraulic cylinder is controllable.
  • the necessary for this Control valve assembly includes a stroke control valve about the pressure medium from the pressure supply unit can be fed into the drive pressure chamber of the stroke drive cylinder is, as well as a lowering control valve, by means of whose the outflow of pressure medium from the drive pressure chamber of the linear actuator and thus its lowering operation is controllable.
  • the two valves are, their basic function after designed as 2/2-way proportional valves, the one have a blocking basic position and with increasing deflection their valve piston from the basic position flow paths release with increasing flow cross section, whereby between the consumer port of the boost control valve and the drive pressure chamber of the lifting cylinder a check valve is switched by relatively higher Pressure at the consumer connection than in the drive pressure chamber is continuous and otherwise blocking, and between the consumer connection of the lowering control valve and the drive pressure chamber of the linear actuator an unlockable check valve is switched that in the blocking basic position of the lowering control valve is blocking and with whose transition to the flow position is switched.
  • control valves In an electrically controllable design of these control valves are their valve bodies with the armatures of electromagnet systems coupled with movement and when energized essentially proportional to the excitation current against the Restoring force of valve springs that move the valve body when the magnets are de-energized in the basic position of the valves hold.
  • the energization of the field windings takes place through output currents of an electronic Control unit that this according to setpoint input signals generated, e.g. by hand lever or rotary button actuation of an analog signal generator by a forklift driver can be triggered, the electronic Control unit, however, also in digital format, e.g. at Using a radio remote control can be entered and by means of this into the - analog - excitation currents can be implemented for the field windings of the control magnets.
  • the object of the invention is therefore a hydraulic installation of the type mentioned at the outset to improve that even with a small amount of a load to be lowered a comparatively high lowering speed can be used is, and that at the same time simple construction of the stroke control valve assembly an increased level of accuracy of adjustment the effective in the raising and lowering operation Flow cross sections is guaranteed.
  • the stroke control valve arrangement is a multi-way / 3-position valve trained that has a main piston which by means of an electric servomotor in his various functional positions of the stroke control valve arrangement corresponding positions is movable by positive movement coupling of the valve piston with the Output shaft of the servomotor in a defined relation to the azimuthal positions related to a reference position stand of the rotor of the servomotor, the servomotor is designed as a digitally controllable motor, the Rotor into a digital control signal, e.g. the number a sequence of control pulses, coded azimuthal position its output shaft - forcibly - reached.
  • a pressure sensor is also provided, that for the pressure in the drive pressure chamber of the stroke drive cylinder characteristic electrical output signals generated, which is fed to an electronic control unit are in accordance with this pressure and thus also load-characteristic output signals of the pressure sensor an automatic limitation of the modulation stroke of the Main piston of the stroke control valve mediated to an amount which is a maximum load and permissible load and The lowering speed of the lift corresponds to below each of which is a dynamically stable, essentially vibration-free operation of the lift is guaranteed is.
  • a design of the electronic control unit which is expedient for the lowering operation can consist in that, with decreasing load, an increase in the actuation range of the valve piston is permitted, in that the same value of the maximum lowering speed can be used for all loads.
  • Due to the mass dependency of the characteristic frequency ⁇ 0 of a hydraulic powertrain, generally by the relationship ⁇ 0 C m is given, in which the hydraulic stiffness of the drive train is denoted by C and the moving mass is denoted by m, larger speeds and accelerations or decelerations can also be used with decreasing amount of the moving mass.
  • Such a transmission is in a preferred design as Spindle nut drive formed, in which preferably the Spindle as a threaded section of the output shaft of the servomotor is trained and the spindle nut firmly with the Piston connected and preferably in one piece with the piston is executed, which in turn is secured against rotation in the valve housing is slidably guided.
  • the design of the stroke control valve arrangement provided according to claim 4 with two controllable by deflections of the main piston Seat valves, by means of which the lowering movements the lift is controllable has the advantage that all valve elements of the stroke control valve assembly in a single multi-way three-position valve with a single actuator and a simple one and space-saving construction is achieved.
  • the pulse-width-modulated solenoid valves provided according to claim 8 for the operation control of further hydraulic drives of the hydraulic installations, for the values of frequencies f m for the amplitude modulation and for the pulse repetition frequency f i of "carrier" pulses indicated by the features of claim 9 are from which the amplitude or duration-modulated pulses of the duration T 1 and T 2 are synthesized, have the advantage that from a minimum current of the time-modulated pulses the deflection of the valve body from the respective basic position regardless of the current of the Impulse is, ie only depends on the ratio T 1 / T 2 , which in turn can be controlled digitally, with the result that the reproducibility of defined deflections is considerably better in relation to conventional proportional solenoid valves.
  • Control block a multi-layer structure made of segment sheets provided that they are cohesively connected, are brazed together in practice and with recesses are provided by their contours and Arrangement to each other the cross-sectional shapes and the clear Dimensions of transverse and longitudinal channels as well as valve channels and control chambers within the control block are, which are required to form the cavities mentioned Openings e.g. in a laser cutting process or created using fineblanking or stamping technology are.
  • the manufacture of the control block is therefore essential easier than manufacturing using conventional casting technology.
  • the solder material required for the solder connection can be inserted in segment recesses in a prepared for stacking segment sheet metal in closed cavities form from which the solder passes through the capillary action of the narrow gaps between the segment sheets into the configuration connecting this large area can reach.
  • Pressure (P) supply channels and return channels, to the supply connections of the individual Valves can be easily bypassed of cross channels in which e.g. Sliding valve piston are arranged completely within the housing block be formed.
  • For connection to hydraulic consumers or to the connection piece provided on the pressure supply unit can be designed as prefabricated parts, which are soldered into channel openings of the control block. Compared to those made with conventional casting technology Housings are significant for the control block smaller outer dimensions and also a considerable weight reduction.
  • Fig. 1 is a total of 10, the hydraulic installation a forklift vehicle, not otherwise shown referred to, by means of which loads up to several tons, e.g. with heavy metal parts loaded transport pallets, for storing them Parts of the designated storage spaces of a high-bay warehouse parked or removed from such storage locations can be, the approach to such bearings and the storage of the goods on them or their removal is controlled by such a driver, the forklift "drives" and "controls".
  • Such a forklift truck if it is for one Use in closed storage rooms is intended to be a battery powered, electric drive and - also emission-free - hydraulic drives for additional equipment, by means of which the load in the storage position brought and stored there or in the storage position approached and picked up again can.
  • the hydraulic installation 10 includes the forklift a stroke drive cylinder 11, by means of which one - fork-shaped - lift, which take up the payload can, on a not shown, substantially vertically Move the mast of the forklift up and down can be made to go to predetermined heights of storage floors Raised or picked up from these can.
  • This stroke drive cylinder 11 is a single-acting linear hydraulic cylinder designed by valve-controlled Pressurization of a drive pressure chamber 12 in In order to raise the lift or the load works and with valve-controlled pressure relief this too Drive pressure chamber 12 by the weight of the piston 13 of the stroke drive cylinder 11 supported load Lowering mediated.
  • the lifting and lowering movements of this lifting drive cylinder 11 are controllable by means of a stroke control valve 14, which is designed as a three-position directional valve, the one functional position I assigned to the lifting operation, one to the Lowering operation of the stroke drive cylinder 11 assigned Function position II and one of the shutdown of the lifting drive cylinder 11 assigned basic position has 0, the the driver by means of a manually operated direction selector 106, e.g. a pivot lever, can specify wherein the stroke control valve is designed so that when the driver does not operate the direction selector 106 - "lets go" - automatically into the return springs 17 and 18 centered home position 0, in which the stroke drive cylinder 11 is stopped.
  • a stroke control valve 14 which is designed as a three-position directional valve, the one functional position I assigned to the lifting operation, one to the Lowering operation of the stroke drive cylinder 11 assigned Function position II and one of the shutdown of the lifting drive cylinder 11 assigned basic position has 0, the the driver by means of a manually operated direction selector 106, e.g.
  • the hydraulic installation 10 includes one Inclination adjusting cylinder 19, by means of which in the front area of the vehicle immediately in front of its front axle Lift mast within a limited angular range around a parallel to the front axle of the truck running axle close to the road to the vehicle can be tilted towards or away from the vehicle to thereby also one to the lane or to the storage area of the stored goods downward or upward orientation of the fork of the forklift, i.e. the for that Loading and unloading and good orientations for driving of the mast and the fork.
  • the tilt actuator cylinder 19 is a double-acting linear Hydraulic cylinder designed, the bottom-side drive pressure chamber 21 and its rod-side drive pressure chamber 22 by means of these individually assigned preload valves 23 and 24, which act as pressure relief valves are designed with adjustable pressure limit values, are kept under a minimum pressure.
  • Thrust actuator 26 is provided for moving the load is usable from the fork to the bearing on which the stored goods are to be parked.
  • This thrust drive is also in Fig. 1 by a double-acting represents linear hydraulic cylinder 26.
  • the lift of the forklift with a low-build, only schematically indicated rotary table 27 is equipped, the by means of a hydraulic one designated 28 overall Rotary drive by at least 180 ° clockwise and counterclockwise is rotatable so that one on the turntable 27 pallets parked in any case in one for parking desired, any orientation is rotatable before them by means of the thrust drive 26 on the respectively provided Storage space is moved.
  • this rotary drive is realized by means of two single-acting linear hydraulic cylinders 28 1 and 28 2 , which can be actuated by alternative pressurization and relief of their drive pressure chambers 29 1 and 29 2 arranged on the rod side to drive the rotary table 27 in one or the other direction of rotation ,
  • a toothed belt 32 which meshes with a gear 31 of the rotary table 27 can be provided, which adjoins the piston rods 30 1 and 30 2 which run parallel to one another Hydraulic cylinder 28 1 and 282 connects to each other and is held in a form-fitting engagement on a 180 ° circumferential area of the gear 31.
  • the Thrust cylinder 26 and the rotary drive 28 are each individually assigned proportional valves 33, 34 and 36 of the same Provided type, which is subsequently based on the Thrust cylinder 26 associated thrust control valve 34 explained becomes:
  • the thrust cylinder control valve 34 is a linear slide valve trained, the piston, corresponding to the functions mediated by the control valve 34 through a 5/3-way valve symbol 34 'is represented. Corresponding are the valve pistons of the other two control valves 33 and 36 with 33 'and 36' respectively.
  • a double-stroke magnet system is used to actuate the control valve 34 37 provided, the two by a control connection 38 or 39 represented field windings, in the non-energized state of the piston 34 'of the control valve 34 by the action of preloaded valve springs 41 and 42 occupies its centered center position, which the Home position 0 of the control valve 34 corresponds to the the shutdown of the push cylinder 26 is linked.
  • a sufficiently high modulation frequency f m of, for example, 500 Hz, with which the control windings 38 and 39 of the double-stroke magnet system 37 are driven alternately with current pulses of the same current intensity but different pulse durations T 1 and T 2 within the period T of the current pulses, is used by the Mechanical inertia of the armature of the double-stroke magnet system 37 and of the valve piston 34 'which is coupled to this in motion, that the reciprocating movements of the armature and the valve piston which occur in time with the modulation frequency f m only have amplitudes which are small compared to the deflections of the valve piston 34' from it Home position 0, so that the effective deflection from the home position 0 is determined by the ratio of the time periods T 1 and T 2 .
  • the control valve 34 is hydraulic in terms of achievable Pipe connections a 5/3-way valve that a pressure (P) supply connection 48 on the supply side has, via a pressure supply line 49 to the pressure outlet 51 of the pressure supply unit, designated overall by 52 connected, a return (T) connection 53, which is connected via a return line 54 the reservoir 56 of the pressure supply unit 52 connected and a load (x) sensing connector 57 associated with one of the connected consumers 26
  • Inlet port 58 of a shuttle valve 59 connected is, depending on whether the load sensing connection 57 prevailing pressure is lower or higher than the pending at the other inlet connection 61 of the shuttle valve 59 Pressure the load sensing port 57 of the control valve 34 blocks against the output 62 of the shuttle valve or connects to the output 62 of the shuttle valve 59.
  • control valve 34 On the consumer side, the control valve 34 has an A consumer connection 63, the one with the bottom-side drive pressure chamber 21 of the push cylinder connected as a consumer 26 is connected, and a B consumer connection 64, the with the rod-side drive pressure chamber 22 of the thrust cylinder 26 is connected.
  • the consumer connections are in the basic position 0 of the control valve 34 63 and 64 against each other and against Supply connections 48 and 53 blocked, but is the T-return port 53 "internal" with the load (x) sensing port 57 connected.
  • the pressure supply port 48 of the valve 34 connected to its B consumer connection 64 and internally with the load sensing connection 57, which is now against the return port 53 is blocked, which in turn is connected to the A consumer terminal 63.
  • the shuttle valve 59 provides a comparison of the drive pressures in the respective pressurized drive pressure chamber 21 or 22 or 29 1 or 29 2 of the thrust cylinder 26 or the rotary drive hydraulic cylinder 28 1 or 28 2 and thus a load comparison, the higher of these two operating pressures being present at the output 62 of the shuttle valve 59.
  • the output 62 of this "comparison" shuttle valve 59 is with the one inlet connection 67 of a further “comparison” shuttle valve 68 connected to the tilt actuator 19 is associated with the second inflow port 69 of this shuttle valve 68 with the load sensing connection 57 of the tilt control valve 33 connected is.
  • the pressure (P) supply connection 48 of the tilt control valve 33 is connected directly to the pressure supply line 49, which is connected to the pressure outlet of the pressure supply unit 52; however, a nonreturn valve 70 1 and 70 2 is connected between the A consumer connection 63 of the tilt control valve 33 and the rod-side drive pressure chamber 22 of the tilt actuating cylinder 19 and between the B consumer connection 64 and the bottom drive pressure chamber 21 of the tilt actuating cylinder 19 , which is blocking at higher pressure in the respective drive pressure chamber 22 or 21 than at the associated consumer connection 63 or 64, so that a set mast inclination is reliably maintained even when the inclination adjusting cylinder 19 is stopped and does not change under the mast's own load can.
  • minimum pressure values are determined and can be preset, which, when the mast inclination changes, in that of the drive pressure chambers 21 and 22 of the inclination actuating cylinder 19 are maintained from which pressure medium must flow to change the position.
  • Stroke control valve 14 is, in functional analogy to the other consumers 19, 26 and 28 of the hydraulic installation 10 associated control valves 33, 34, and 36, designed as a 5/3-way proportional valve.
  • the stroke control valve 14, as well as that for the others Consumers 19, 26 and 28 provided control valves 33, 34 and 36, a pressure (P) supply connection on the supply side 48, with the pressure supply line 49 communicating directly, a return (T) connector 53, which communicates directly with the return line 54 is connected, and a load (x) sensing terminal 57, the one with the inlet connection 71 of a functional the shuttle valves 59 and 68 corresponding others Shuttle valve 72 is connected, and, consumer side, a B consumer port 64 that is direct communicating with the drive pressure chamber 12 of the stroke drive cylinder 11 is connected, and an A consumer connection 63, the to the drive pressure chamber 12 of the stroke drive cylinder 11 is connected via a check valve 73, which by relatively higher pressure at the A consumer port 63 of the control valve 14 than its B consumer connection 64 Flow position assumes and is otherwise blocking.
  • the second inlet port 74 of the one with the load sensing port 57 of the stroke control valve 14 connected on one side Shuttle valve 52 is connected to the outlet 76 of the tilt control valve 33 associated shuttle valve 68 connected.
  • the output 77 of the stroke control valve 14 assigned Shuttle valve 72 is one with the load pressure connection 78
  • Two-way pressure compensator 79 connected, its reference pressure connection 81 to the pressure outlet 51 of the pressure supply unit 52 is connected, from which the pressure supply line 49 to which the pressure (P) supply connections 48 of the individual control valves 14, 33, 34 and 36, partly via the check valves 66, connected are.
  • a pressure relief valve 83 is located between the load pressure connection 78 of the pressure compensator 79 and the return (T) connection 82, from which the return line 54 starts, which is connected to the respective return connections 53 of the control valves 14, 33, 34 and 36 switched, which limits the operating pressure with which the individual drives 11, 19, 26 and / or 28 can be acted upon, to a predeterminable adjustable maximum value P max of 100 bar.
  • the piston represented by the 2/2-way valve symbol 84 of the pressure compensator 79 forms with its opposite one another schematically indicated end faces 86 and 87 same effective area the axially movable pressure-tight Limits of an operating pressure chamber 88, in which the Load pressure connection 78 of the respective operating pressure is coupled which is activated when one of the drives is activated Actuation of its control valve and a reference pressure chamber 89, in via the reference pressure connection 81 the outlet pressure of the hydraulic pump 91 of the pressure supply unit 52 is coupled, which means of an electric drive motor 92 is driven and in operation with a substantially constant delivery rate is working.
  • the piston 84 is the Pressure compensator 79 pushed into its locked position.
  • the Pressure compensator due to the effect of the reference pressure chamber 89 coupled output pressure of the pump 91 in their Flow position I and thus works in circulation, in the hydraulic medium from the pump 91 via the pressure compensator 79 is conveyed back into the storage container 56, whereby - because of the effect of the balance spring - above the pressure balance there is a pressure drop of 3 bar.
  • a total of 94 designated spindle drive provided the one by means of a pulse-controlled electric motor 96, e.g. a stepper motor can be driven in rotation Threaded spindle 97 and one in meshing with this Engaged spindle nut 98 which is fixed to the Valve piston 14 'of the stroke control valve 14 is connected, the by means of a housing-fixed, radial pin 95, the protrudes into a longitudinal groove 99 of the piston against rotation is secured within a housing bore 101 and in this can nevertheless be easily moved axially back and forth is led.
  • a pulse-controlled electric motor 96 e.g. a stepper motor
  • Threaded spindle 97 e.g. a stepper motor
  • the electromotive actuating device explained so far 94, 96 of the stroke control valve 14 enables one very fine "digital" graded adjustment of the deflections of the piston 14 'of the stroke control valve 14 compared to that Standstill of the lift assigned to the middle position as Home position 0, for recording an electronic 102 or electromechanical reference signal generator provided is the one for the - spring centered - middle position of the Piston 14 'characteristic electrical reference signal to one provided to control the stepper motor 96 outputs electronic control unit 103, based on which the electronic control unit 103 automatically detects when the piston 14 'is in the basic position 0 or this goes through.
  • the electronic control unit 103 is supplied with electrical output signals of a setpoint specification unit 104 1 as information inputs, by actuating them, for example by means of a hand lever 106 which can be pivoted back and forth, the forklift driver corresponds to the setpoint signals corresponding to the driver's request with regard to the operating mode - raising or lowering Hoist drive cylinder 11 and in terms of the speed at which the lifting or lowering operation is to take place.
  • individually assigned setpoint specification units 104 2 , 104 3 and 104 4 are provided for the tilt actuator 19, the thrust drive 26 and the rotary drive 28, which, analogously to that for the Control of the lifting and lowering operation of the setpoint specification unit 104 1 provided can be actuated by means of a separate hand lever 106 or a rotary knob 106 ', the setpoint output signals of the individual setpoint specification units 104 1 to 104 4 of the electronic control unit 103 being at a separate setpoint -Inputs 109 1 to 109 4 are fed.
  • Another input for information is the electronic one Control unit 103 the electrical output signal of a electronic or electromechanical pressure sensor 107 fed that is a direct measure of that in the drive pressure chamber 12 of the stroke drive cylinder 11 prevailing operating pressure and therefore also a measure of the load, which means the lift of the forklift raised or lowered shall be.
  • This function of the electronic control unit 103 is particularly important for the lowering operation of the lifting platform, in which only the load supported on the piston 13 of the lifting drive cylinder 11 is effective for developing the pressure which conveys the return flow of the hydraulic oil to the reservoir 56, so that it is around
  • it is necessary to control a larger flow cross-section of the flow path 108 of the control valve 14 which is effective in the lowering operation than with a comparatively higher load, under which a higher pressure results in the drive pressure chamber 12, which is already at lower flow cross-section of the flow path 108 of the control valve used in the lowering mode (and correspondingly stronger throttling effect of the same) is sufficient to achieve a lowering speed preselected by the setpoint specification unit 104 1 .
  • the electronic control unit 103 also generates the relatively high-frequency control pulse sequences required for the operation control of the tilt control valve 33, the thrust control valve 34 and the rotary control valve 36 for their double-stroke magnet systems 37, as well as control signals for the battery-powered drive motor 92 the high pressure pump 91 of the pressure supply unit 52, by means of which the delivery rate can be controlled as required.
  • Such control is expediently carried out in such a way that the hydraulic drive circuits controlled by one of the control valves 14, 33, 42 and / or 36, which are represented by the respective drive cylinders 11, 19, 26 and 28 1 and 28 2 , can work in a dynamically stable manner , however, to keep the hydraulic oil flow that flows through the pressure compensator 79 to the reservoir 56 in the control mode at the lowest possible value in order to keep the power loss caused by this circulating oil flow as low as possible.
  • Such a type of speed or power control of the electric drive motor 92 is possible in the exemplary embodiment selected for explanation at least for the lifting and lowering operation of the lifting drive cylinder 11, in which the operating pressure prevailing in the drive pressure chamber 12 is monitored by means of the pressure sensor 107.
  • Control block shows in which the stroke control valve 14th and the pressure compensator 79 are integrated, as well as the check valve 73, which is between the A consumer connection 63 of the stroke control valve 14 and the drive pressure chamber 12 of the Hub drive cylinder 11 is switched, as well as the stroke control valve 14 assigned shuttle valve 72 and that too Shuttle valve 68, which is used to sense the operating pressure on the inclination control valve not shown in FIG. 2 33 is provided.
  • This control valve 33 and the further control valves 34 and 36 can be added to the one for the stroke control valve 14 shown in an analogous manner in the Control block 110 may be integrated.
  • the arrangement of the stroke control valve 14 and the pressure compensator 79 and the check valve 73 is taken so that their central longitudinal axes 111 and 112 and 113, along which their pistons can be pushed axially back and forth, as well the central longitudinal axes 114 and 116 of the P supply connection 48 or the T return connection 59 in the longitudinal median plane marked by the plane of the drawing of the control block 110.
  • the control block 110 has a multilayer structure made of hard-soldered segment sheets hen 122 1 to 122 14 , which are arranged in the order of their indices one above the other or side by side with
  • the segment sheets 122 1 to 122 14 are provided with punched-out and / or, for example, cut-outs in a laser cutting process, the shape of the contours and, if necessary, the coaxial arrangement of each other, predetermine cross-sectional shapes and clear dimensions of transverse and longitudinal channels within the control block 110.
  • the segment plates are provided 122 1-122 8 with circular holes 123 1 to 123 8 of the same diameter, which form a cross-channel 123 in mutually aligned arrangement, in the connection socket 48 'of the pressure (P) supply connection 48 is soldered.
  • This transverse channel 123 opens into a longitudinal slot 124 of the ninth segment plate 122 9 , which together with the segment plates 122 8 and 122 10 forms the pressure supply line 49 (FIG. 1), which connects to the pressure (P) supply connections 48 of the individual control valves 14 , 33, 34 and 36 is connected.
  • Segment sheet 122 14 are provided in a coaxial arrangement with respect to the central longitudinal axis 111 of the stroke control valve 14 with circular, mutually aligned, smoothed through post-processing recesses 126 8 , 126 10 , 126 12 and 126 14 , the sliding seats for radial flanges 127, 128 and 129 by means of of the stepper motor 96 form axially displaceably drivable valve piston 14 ', by means of which the piston is mounted in the part of the control block 110 which forms the valve housing and is pressure-tight and axially smoothly displaceable.
  • the segment sheets 122 1 to 122 5 are provided in a coaxial arrangement with respect to the central longitudinal axis 116 of the T return connection 53 with further circular recesses 131 1 to 131 5 which are aligned with one another and form a transverse channel 131 into which the connecting piece 53 'of the T -Return connection is soldered.
  • This transverse channel 131 opens into the return line 54 which runs between the fifth segment plate 122 5 and the eighth segment plate 122 8 in the exemplary embodiment shown and which extends on the one hand to the return connection region of the stroke control valve 14 and further bypasses the transverse channel 123 by - not shown - continues the area of the control block 110, in which the return connections 53 of the further control valves 33, 34 and 36 are located.
  • the shape of the recesses 132 6 and 132 7 of the segment sheets 122 6 and 122 7 , which between the segment sheets 122 5 and 122 8 determine the shape of the part of the return line 54 which extends from the transverse channel 131 to the region of the stroke control valve 14, is selected that with the central longitudinal axis 111 of the stroke control valve concentrically curved edge areas 133 6 and 133 7 of the return line recesses 132 6 and 132 7 of the two segment plates 122 6 and 122 7 at a significant radial distance from the edge of the sliding seat opening 126 8 of the segment plate 122 8 run in which the piston flange 127 is slidably sliding, which is arranged on the side of the valve piston 14 'facing away from the drive motor 96, and that the circular mouth edges 134 5 and 134 8 (FIG.
  • the one transverse channel 136 is formed by circular openings 136 2 , 136 3 , 136 4 and 136 5 of the segment sheets 122 2 to 122 5 which are aligned with one another and is closed on the outside in a pressure-tight manner by a stopper 138 which is in one with the common central longitudinal axis 112 of the segment sheet -Openings 136 2 to 136 5 coaxial recess 136 1 slightly larger diameter of the segment plate 122 1 is fixed.
  • the other transverse channel 137 is formed by aligned circular openings 137 8 and 137 10 to 137 14 of the segment sheets 122 8 and 122 10 to 122 14 and is closed on the outside by another, block-shaped, side housing end part 139 pressure-tight to the outside.
  • the segment sheets 122 1 and 122 3 to 122 10 are provided with circular recesses 141 1 and 141 3 to 141 10 , which are arranged coaxially with respect to the central longitudinal axis 113 of the check valve 73, which is between the A consumer port 63 of the stroke control valve 14 and the drive pressure chamber 12 of the stroke drive cylinder 11 is switched.
  • the second segment plate 122 2 arranged between the segment plates 122 1 and 122 3 has a recess 141 2 which has an edge region 142 which is coaxially curved with the central axis 113 of the check valve 73 and an edge region 143 which is coaxially curved with the central longitudinal axis 111 of the stroke control valve 14
  • the curved edge regions 142 and 143 of the recess 141 2 of the segment plate 122 2 which overlap with the recesses 141 1 and 141 3 and the recesses 144 1 and 144 3 of the segment plates 122 1 and 122 3 , each close with a smooth curvature and rectilinear edge regions 148 of the recess 141 2 .
  • the housing channel which is kept free by the recess 141 2 of the segment plate 122 2 and which extends between the B-consumer connection chamber 118 of the stroke control valve 11 and the connection channel coaxial with the central longitudinal axis 113 of the check valve 73 forms, as it were, the B-consumer connection 64 of the stroke control valve 14 ,
  • the transverse channel coaxial with the central longitudinal axis 113 of the check valve 73, designated overall by 141, has in the central region of the control block 110 a conical taper forming the valve set 149 for the valve body 151 of the check valve 73 shown in the shape of a truncated cone, with which it connects to the A-consumer connection channel 63 connects, which is formed by the mutually aligned recesses 141 7 to 141 10 of the segment plates 122 7 to 122 10 .
  • the A-consumer connection channel 63 opens into a "flat" -eliptically bordered recess 126 11 of the eleventh segment plate 122 11 , which, depending on the functional position of the piston 14 'of the stroke control valve, either via a throttle gap opened in the valve is connected to the pressure supply line 49 and is blocked off from the T return line 54 or is connected to it and is blocked off from the pressure supply line 49.
  • This elliptically bordered recess 126 11 of the segment plate 122 11 also mediates the communicating connection of the A consumer connection 63 of the stroke control valve 14 to its load sensing connection 57 (FIG. 1).
  • the recess 132 7 bordering part of the return line 54 of the segment plate 122 7 arranged approximately at the level of the valve seat 149 has a recess 141 7 , the edge of which forms part of the valve seat 149, with a radially spaced arcuate bulge 153 with a transverse channel 154, the central longitudinal axis 156 of which runs parallel to the central longitudinal axes 113 and 111 of the check valve 73 and the stroke control valve 14 and in their plane, is in communicating connection.
  • This transverse channel 154 is formed by circular openings 154 8 to 154 12 of the segment plates 122 8 to 122 12 which are aligned with one another; it also communicates with a "tank space" recess 126 13 of the segment plate 122 13 , which has an arcuate border area with the central longitudinal axis 111 of the stroke control valve 14 and an opening area 157 extending from it, and a slot-shaped bulge 158 extending therefrom, within the end section of which the transverse channel has 154 opens into the overall keyhole-shaped recess 126 13 of the segment plate 122 13 .
  • the radius of curvature of the arcuate opening edge region 157 'of the tank space recess 12613 is somewhat larger than the radius of the sliding fit recesses 126 8 , 126 10 , 126 12 and 126 14 , in which the piston 14 is coaxial with the central longitudinal axis 111 of the stroke control valve 14 'With its piston flanges 127, 128 and 129 is slidably arranged so that between the 12th and the 14th segment plate 122 12 there is an annular space 159 which extends over the slot-shaped bulge 158 of the tank space recess 126 13 , the transverse channel 154 and the arcuate curved bulge 153 of the "tank" recess 132 7 of the segment plate 122 7 with the T-return line 54 is in constantly communicating connection.
  • the segment plate 122 12 is provided with a circular opening 166 which is small in diameter and which forms the one inlet connection 71 of the shuttle valve 72 which is provided on the stroke control valve 14 for load comparison.
  • the 14th sheet segment 122 14 is provided with a recess 167 of somewhat larger diameter, which is coaxial with the aforementioned recess 166 and into which a valve sleeve 168 is inserted in a pressure-tight manner, which forms the second inlet connection 74 and the valve seat of the shuttle valve 72 opposite the first inlet connection 71.
  • the outlet 77 of this shuttle valve 72 which is connected to the operating pressure chamber 88 of the pressure compensator 79, is formed by a bulge 169 of the largely round recess 137 13 of the segment plate 122 13 which is coaxial with the central longitudinal axis 112 of the pressure compensator and which also extends to the valve space extending between the valve seats of this valve limited.
  • the segment plate 122 12 is provided with a further “small”, circular recess 171, which forms the one inlet connection 69 of the shuttle valve 68, which is connected to the load sensing connection 57 of the tilt control valve 33.
  • a connection channel required in this regard is represented by the recess 172 of the segment plate 122 11 .
  • a valve sleeve 174 is inserted in a pressure-tight manner, which forms the inlet connection 67 of the change-over valve 68 associated with the inclination control valve 33 and one of its two valve seats.
  • a substantially slot-shaped recess 176 of the segment plate 122 13 forms with a curved area coaxial with the recess 171 of the segment plate 122 12 the boundary of the space of the shuttle valve 68 which extends between the valve seats and which is assigned to the inclination control valve 33 and mediates the communicating connection of the valve outlet 76 with a circular connection recess 177 of the segment sheet 122 14 from which a connection channel leads to the second inlet connection 74 of the shuttle valve 72 assigned to the stroke control valve.
  • functionally analogous recesses in the segment plates 122 13 and 122 14 are designated 176 'and 177' in FIGS. 31 and 3m.
  • Stroke control valve 14 which in FIG. 2 in its load-lifting operation assigned functional position I shown is now also supplementary to FIGS. 2a, 2b and 2c Referenced in which the various functional positions I, 0 and II of the stroke control valve 14 assigned Functional positions of a total designated 14 '' Lowering valve unit in relation to the different ones Positions of the positions assigned to Main piston 14 'are shown.
  • the lowering valve unit 14 '' can be preassembled Assembly of the stroke control valve 14 in the housing part 117 integrated on the side of the multi-layer control block 110 is attached and against this by means of the seals 147 and 178 and with another ring seal 179 is sealed in the area of the consumer Connection piece 181 is arranged, which is also on the Housing part 117 is arranged.
  • This partition 182 has one with the central longitudinal axis 111 of the Stroke control valve 14 coaxial, central bore 186, in the a cylindrical-pot-shaped "outer" valve body 187 is slidably arranged in a pressure-tight sliding manner.
  • This central partition wall bore 186 is slightly larger than the diameter D2 one with this coaxial tank compartment side opening 188 of the housing part 117 formed by an inner annular rib 189 of the sleeve Extension 146 of the housing part 117 is edged, through which the B-consumer connection chamber 118 against the Tank chamber 54 'is offset by the in the area of Stroke control valve 14 extending portion of the return line 54 is formed.
  • connection chamber 191 of the opening 188 bordered by the annular rib 189 forms a circular valve seat for the cup-shaped Valve body 187 with a circular cone Sealing surface 192, over which an outer cylindrical outer surface 193 to the bottom area 194 of the valve body 187 connects, can be supported on the valve seat 191.
  • the valve body base 194 whose tank space-side boundary surface 196 extends radially within the conical sealing surface region 192 at right angles to the central longitudinal axis 111 and whose inner boundary surface 197 in the central bottom region near the axis also extends at right angles to the central longitudinal axis 111, has a central opening 198 in this region, the diameter of which d 1 is significantly smaller than the inner diameter d 2 of the nevertheless relatively thick-walled cylinder jacket 199 of the cup-shaped valve body 187.
  • the inner circular edge 201 forms the seat for a dome-shaped or frustoconical as shown Sealing body 202 of a second valve body 203 of the lowering valve unit 14 ′′, which acts as a stepped piston is formed with its larger diameter Piston stage 204 against the inner lateral surface 206 of the Cylinder jacket 199 of the cylindrical pot-shaped valve body 187 is slidingly sealed.
  • This outside cylindrical Piston stage 204 is in turn cylindrical-pot-shaped, being in communication with the outer pressure chamber 183 Connected interior 207 via a longitudinal channel 209 axially penetrating bottom region 208 and communicating with this transverse channels 211 of the Diameter after smaller piston stage 212, which in the frustoconical Sealing body 202 runs out with the the two valve bodies 187 and 203 bordered inner annular space 213 of the lowering valve unit 14 '' in constantly communicating Connection is established.
  • the - annular space - consumer connection chamber 118 is via a fixed throttle 217 with the outer pressure chamber 183 in constantly communicating connection, so that in the in the 2 and 2a shown, locking configuration of the Lowering valve unit 14 ′′ in the outer pressure chamber 183 the same pressure as in the B-consumer connection chamber 118.
  • throttle 217 which in the 2 and 2a as a stepped bore parallel to the central Longitudinal axis 111 of the stroke control valve 14 extending central Axis 218 is shown, corresponding throttle could also, as indicated by dashed lines, by a narrow longitudinal groove 217 'shallow radial depth of the outer Valve body 187 of the lowering valve unit 14 '' or a corresponding longitudinal groove 217 ′′ of the central bore 186 the intermediate wall 182 of the lowering valve unit 14 ′′ receiving housing part 117 can be realized.
  • the housing part 117 containing the lowering valve unit 14 ′′ which must be prefabricated as a separate part from the control block 110 in the exemplary embodiment of the hydraulic installation 10 selected for explanation, can be described in detail in the structure of the control block 110
  • the layering technique explained can be composed of segment sheets 1171 to 11710, if necessary, of different thicknesses, for which a possible division is indicated by dashed-line solder joints 220 (FIG. 2a), with the selection of which only minor and easy preprocessing of the segment sheets 117 4 , 177 5 and 117 6 are required before the segment sheet package 117 1 to 117 10 forming the housing part 117 can be soldered together.
  • the overall configuration of the arrangement shown in FIG. 2 of the motor-controlled main piston 14 ', the valve body 187 and 203 of the lowering valve unit 14 '' of Stroke control valve 14, the piston 84 of the pressure compensator 79, the Valve body 151 of the check valve 73, the valve ball 221 of the shuttle valve 14 associated with the stroke control valve 72 and the valve ball 222 of the tilt control valve 33 assigned shuttle valve 68 corresponds to a stationary Operating state of the hydraulic installation 10, in which the piston 13 of the stroke drive cylinder 11 with constant Speed in load-lifting mode moved upwards, while the other hydraulic drives 19, 26 and 28 have stopped, i.e. the control valves assigned to them 33, 34 and 36 in their blocking basic positions 0 are held.
  • the motor-driven is in the above-mentioned stationary operating state Main piston 14 'so far from its spring centered Middle position - away from the lowering valve unit 14 '' - disengaged that an annular groove 223 of the piston 14 ', the 128 between the central piston flange and its piston chamber-side piston flange 127 arranged is and in every possible position of the motor-driven Piston 14 'in communication with the pressure (P) supply line 49 Connection is established via the now released Throttle gap 152 also with the A consumer connection 63 is communicatively connected and pressure medium over this and the one opened against the action of its valve spring Check valve 73 in the drive pressure chamber 12 of the stroke drive cylinder 11 can flow.
  • the flow path required in this regard, to which the reference pressure connection 81 corresponds in the circuit diagram in FIG. 1, is through a transverse channel 224 which is in constant communication with the pressure (P) pressure supply line 49 and also with this and with the reference pressure chamber 89 of the pressure compensator 79 formed in a continuously communicating longitudinal channel 226 of the pressure compensator piston 84.
  • the pressure compensator piston 84 Due to the positive pressure difference ⁇ p between the reference pressure p R coupled into the reference pressure chamber 89 in the stationary operating state and the operating pressure p B coupled into the operating pressure chamber 88 of the pressure compensator 79, the pressure compensator piston 84 has an equilibrium position deflected against the restoring force of the balance spring 93 compared to its basic position, in which a throttle gap 229 is released between a piston-side control edge 227 and a housing-side control edge 228 of the control block 110, via which pressure medium can flow back from the pressure (P) supply line 49 to the unpressurized tank space 54 ′ or to the reservoir 56 of the pressure supply unit 52.
  • the pressure p B prevailing in the drive pressure chamber 12 of the stroke drive cylinder 11 is also coupled into the B consumer connection chamber and prevails - in the stationary operating state - also in the outer pressure chamber 183 of the lowering valve unit 14 '', the valve bodies 187 and 203 of which are thereby additionally Force against their associated valve seats 191 and 201 are pushed.
  • the main piston 14 'of the stroke control valve 14, controlled by the stepping motor 96 is set to the basic position 0, in which, due to the position of the main piston 14', the pressure (P) supply line 49 is shut off from the a consumer terminal 63, this, however, 128 of the main piston and that arranged adjacent the edge 126 '12 due to a shared in this basic position gap between the central flange at the central longitudinal axis 111 of the lift control valve 14 coaxial recess 126 12 of the segment plate 122 12 of the control block 110 released annular gap communicates with the unpressurized return (T) connection 48.
  • P pressure
  • the starting position 0 of the main piston 14 ' the stroke control valve 14 is expediently motor-controlled, controlled by the electronic control unit 103 to ensure that the lifting platform gently runs in to ensure the standstill and unwanted vibrations or to avoid vibrations.
  • the necessary for this Load information is characteristic of the pressure Output signal of the pressure sensor 107 provided.
  • the stop surface 233 'for the support ring 233 of the motor-side valve spring 17 is formed by a radial inner shoulder of the housing part 119, which forms the housing-fixed boundary of the tank connection chamber 121, within which the spindle drive 94 for driving coupling of the stepping motor 96 to the main piston 14' is arranged ;
  • the stop surface 234 ', on which - in the basic position 0 of the main piston 14' - that support ring 232 is supported, on which the other valve spring 18, which is arranged in the tank space 54 ', acts on the inner ring rib 189 of the lowering valve unit 14'' Housing part 117 is supported, is formed by the edge of the tank chamber side of the circular opening 1268 coaxial with the central longitudinal axis 111 of the stroke control valve 14 of the segment plate 122 8 which delimits the tank chamber 54 'from the pressure (P
  • the main piston 14 'of the stroke control valve 14 has on its side facing the lowering valve unit 14''a cylindrical extension 236 which passes through the support ring 232 arranged in the tank space 54' and whose diameter is slightly smaller than the inside diameter of the support ring 232.
  • This extension tapers over a truncated cone-shaped chamfer 237 to a cylindrical actuating section 238, the diameter d 3 of which is slightly larger than the diameter d 1 of the central opening 198 of the bottom 194 of the cylindrical cup-shaped valve body 187 of the lowering valve unit 14 ′′.
  • This cylindrical actuation section 238 is followed by a slender, tappet-shaped end section 239, the diameter d 4 (FIG. 2b) of which is significantly smaller than the diameter d1 of the central bottom opening 198 of the cup-shaped valve body 187.
  • Pressure medium in the drive pressure chamber 12 of the stroke drive cylinder 11 under one supported by the piston 13 Load and by which the drive pressure chamber 12 is movable limiting piston area is certain pressure now via the B consumer connection 64, the B consumer connection chamber 118, the fixed throttle 217, the outer pressure chamber 183 of the housing part 117, the interior 207, the Longitudinal channel 209 and the transverse channels 211 in the inner annulus 213 of the piston arrangement 187, 203 and over the now released valve gap 242 (Fig. 2b) in the unpressurized Tank space 54 'of the stroke control valve 14 and via this to Outflow the reservoir 56 of the pressure supply unit 52, with the result that the lift of the forklift is lowered becomes.
  • valve gap 242 is significantly smaller than the free flow cross section of the throttle 217, is the Sinking speed essentially due to the throttling effect of the inner seat valve 201, 203 at the given Load determined and by motor-controlled adjustment the valve gap width can be selected.
  • the throttling effect of valve gap 242 is significantly smaller than that of the fixed throttle 217 is at a given load the lowering speed by the fixed throttle 217 determined and limited to a load-dependent maximum value.
  • the load to be lowered is comparatively low and consequently also the pressure under which the hydraulic medium in the drive pressure chamber 12 of the stroke drive cylinder 11 stands, with the possible consequence that the only by Opening of the pre-relief valve 201, 203 achievable lowering speed would be undesirably low, the effective outflow cross-section of the lowering valve unit 14 '' can be enlarged by further deflection of the main piston 14 'also the further, through the cup-shaped Valve body 187 and the associated Valve seat 191 formed valve of the lowering valve unit 14 '' is opened and thereby the qualitatively in 2c shows the configuration of the valve body 187 and 203 is reached in the print medium from both the by the two valve bodies 187 and 203 bordered annulus 213 as well as the outer one, by lifting the Pot-shaped valve body 187 from the valve seat 191 released valve gap 243 directly from the B consumer connection chamber 118 flow into the unpressurized tank space 54 ' can.
  • the cylindrical actuating section 238 of the piston extension 236 is on its level with the tank side Boundary surface 196 of the valve body bottom 194 in Provide notches 244 on the end face reaching the system, then also via the pressure medium from the annular space 213 can flow out sufficiently freely if the cylindrical Actuating section 238 at which the central floor opening 198 surrounding edge area is supported.

Claims (14)

  1. Installation hydraulique pour chariot élévateur à fourche avec un groupe moteur hydraulique de levage pour une plate-forme de levage, avec un au moins un autre groupe moteur hydraulique, en particulier un groupe moteur hydraulique de réglage d'inclinaison, avec des ensembles de vannes attribuées individuellement aux groupes moteurs hydrauliques et pouvant être activés électriquement, à l'aide desquels les pressions de service et les débits de passage de fluide sous pression nécessaires pour les différents mouvements de la plate-forme de levage peuvent être pilotés, le groupe moteur de levage étant conçu comme vérin hydraulique à simple action, dont le fonctionnement en levage et en abaissement est commandable par un flux de fluide sous pression vers la chambre de pression d'actionnement du vérin hydraulique, respectivement par un reflux hors de cette chambre de pression d'actionnement pilotés par des vannes et un ensemble de vannes de pilotage du levage étant prévu pour cela, qui peut être piloté, à partir d'une position de base (0), dans laquelle la chambre de pression d'actionnement du vérin d'entraínement du levage fait l'objet d'un barrage aussi bien par rapport à la sortie sous pression du groupe de production de pression que par rapport à son raccord de retour (T), jusque dans une position de fonctionnement (I) attribuée au mode de levage, dans laquelle la chambre de pression d'actionnement du vérin d'entraínement du levage est reliée avec la sortie d'alimentation en pression (P) du groupe de production de pression mais est fermée par rapport son raccord de retour (T) et qui, en variante par rapport à cela, peut être piloté dans une position de fonctionnement (II) attribuée au mode d'abaissement du vérin d'entraínement du levage, dans laquelle la chambre de pression d'actionnement du vérin d'entraínement du levage est reliée par l'intermédiaire d'un trajet d'écoulement de la vanne, qui est libéré dans cette position, avec le raccord de retour (T) du groupe de production de pression mais est fermée par rapport à sa sortie d'alimentation en pression (P), les valeurs des sections de trajets d'écoulement libérés dans les positions de fonctionnement I et II pouvant être pilotées par commande et des valeurs croissantes des excursions d'un piston de l'ensemble de vannes de pilotage du levage à partir d'une position médiane correspondant à des valeurs croissantes des sections d'écoulement des trajets d'écoulement libérés dans la position de fonctionnement respective (I ou II), caractérisée par les particularités suivantes :
    a) l'ensemble de vannes de pilotage du levage est conçu comme vanne à plusieurs voies et à 3 positions (14), qui comprend un piston principal (14') pouvant être déplacé à l'aide d'un servomoteur électrique (96) dans ses positions correspondant aux différentes positions de fonctionnement (0, I et II) de l'ensemble de vannes de pilotage du levage (14), lesquelles positions ont, par le couplage en complémentarité de forme des mouvements du piston de vanne (14') avec l'arbre de sortie du servomoteur (96), une relation définie avec les positions azimutales du rotor du servomoteur se rapportant à une position de référence ;
    b) le servomoteur (96) est conçu comme moteur pouvant être piloté en mode digital, dont le rotor atteint obligatoirement une position azimutale de son arbre de sortie, qui est codée en un signal digital de pilotage ;
    c) il est prévu un capteur de pression (107), qui produit des signaux électriques de sortie caractéristiques pour la pression dans la chambre de pression d'actionnement (12) du vérin d'entraínement du levage (11), qui sont transmis à une unité de commande électronique (103) qui, en fonction des signaux de sortie du capteur de pression (107) caractéristiques de la pression et de ce fait aussi de la charge, détermine une limitation automatique de la course de réglage du piston principal (14') de la vanne de pilotage du levage (14) à une valeur, à laquelle correspond une vitesse maximale admissible en fonction de la charge pour la levée ou pour l'abaissement de la plate-forme de levage et en-dessous de laquelle un mode de levage et d'abaissement sensiblement exempt de vibrations de la plate-forme de levage est garanti.
  2. Installation hydraulique selon la revendication 1, caractérisée en ce que pour le couplage mécanique d'entraínement du servomoteur (96) et du piston principal (14') de l'ensemble de vannes de pilotage du levage (14) il est prévu une transmission non autobloquante et en ce que la position de base (0) du piston principal (14') est centrée par des ressorts de rappel (17 et 18).
  3. Installation hydraulique selon la revendication 2, caractérisée en ce que la transmission mécanique est conçue comme transmission à écrou et broche (94), dans le cas de laquelle la broche (97) est de préférence conçue comme section de filetage de l'arbre de sortie du servomoteur (96) et l'écrou de broche (98) est relié de manière fixe avec le piston (14') et est de préférence réalisé en une seule pièce avec le piston, qui est guidé de manière coulissante dans le boítier de vanne en étant protégé contre la rotation.
  4. Installation hydraulique selon l'une des revendications 1 à 3, caractérisée en ce que, dans le cas d'une excursion du piston principal de la vanne (14') hors de sa position médiane dans le sens d'un passage dans la position de fonctionnement (II) de l'ensemble de vannes de pilotage du levage (14) attribuée au mode d'abaissement du vérin d'entraínement du levage (11), une première vanne à siège (201, 203) arrive d'abord dans sa position ouverte, dans laquelle une chambre de pression (183) de l'ensemble de vannes de pilotage du levage (14) qui, par l'intermédiaire d'un élément d'étranglement fixe (217) est en liaison de communication permanente avec une chambre de raccordement de consommateurs B (118), qui est en liaison de communication permanente avec la chambre de pression d'actionnement (12) du vérin hydraulique d'entraínement (11), arrive en liaison de communication avec le compartiment de raccordement du réservoir (54') de la vanne de pilotage du levage (14) par l'intermédiaire de la fente de vanne qui s'ouvre progressivement (242) de cette première vanne à siège, et en ce que dans le cas d'une poursuite de l'excursion du piston principal (14') dans le sens d'un accroissement de la section du trajet d'écoulement (108) de l'ensemble de vannes de pilotage du levage (14), une deuxième vanne à siège (187, 191) arrive en outre dans sa position ouverte, par la fente de vanne (243) de laquelle la chambre de raccordement de consommateurs B (118) et avec celle-ci la chambre de pression d'actionnement (12) du vérin d'entraínement du levage (11) arrivent en liaison de communication directe avec le compartiment de réservoir (54') de l'ensemble de vannes de pilotage du levage (14).
  5. Installation hydraulique selon la revendication 4, caractérisée en ce que la première vanne à siège (201, 203) est conçue comme vanne anti-retour intégrée dans la deuxième vanne à siège (187, 191) et pouvant être déverrouillée par le déplacement d'excursion du piston principal de pilotage (14').
  6. Installation hydraulique selon la revendication 5, caractérisée en ce que la deuxième vanne à siège (187, 191) est conçue comme vanne anti-retour pouvant être déverrouillée par le mouvement d'excursion du piston principal (14') et qui, à partir d'une excursion minimale du piston, par l'effet d'impact de ce dernier avec le corps de vanne (187) de la deuxième vanne à siège (187, 191) arrive dans sa position ouverte, dans laquelle, avec la poursuite croissante de l'excursion du piston (14'), la section d'ouverture de la fente de vanne (243) de la deuxième vanne à siège (187, 191) continue à augmenter, la section d'ouverture de la fente de vanne (242) de la première vanne à siège (201, 203) restant toutefois constante.
  7. Installation hydraulique selon l'une des revendications 4 à 6, caractérisée en ce que la deuxième vanne à siège (187, 191) est conçue comme vanne à siège conique, ayant un corps de vanne en tant que douille en forme de pot (187), qui forme avec une section de corps de vanne en forme d'enveloppe cylindrique (199) le boítier pour le corps de vanne (203) de la première vanne à siège (201, 203) étant réalisée en tant que douille en forme de pot, qui possède également un corps d'étanchéité en forme de cône tronqué (202), qui est appuyé à l'aide d'un ressort de vanne (216) contre un siège de vanne (201) de forme circulaire se trouvant sur le fond (194) du corps de vanne (187) de la deuxième vanne à siège, à l'intérieur de laquelle une chambre annulaire (213) est délimitée par une section proche du siège du corps de vanne (187) de la deuxième vanne à siège (187, 191) et par un palier de piston (212), plus petit en ce qui concerne le diamètre, du corps de vanne (203) de la première vanne à siège (201, 203), laquelle chambre annulaire étant, par l'intermédiaire de canaux transversaux (211) du corps de vanne (203) de la première vanne à siège (201, 203), en liaison de communication permanente avec la chambre de pression extérieure (183) de l'ensemble de vannes de pilotage du levage (14).
  8. Installation hydraulique selon l'une des revendications 1 à 7, dans le cas de laquelle l'autre(les autres) vérin(s) hydraulique(s) est(sont) réalisé(s) respectivement à l'aide d'un vérin hydraulique à double action ou à l'aide d'une paire de vérins hydrauliques pouvant être exploités en symétrie, qui peut (peuvent) être piloté(s) au moyen d'une vanne à plusieurs voies et à 3 positions, dont le système magnétique de pilotage est conçu comme système à double levage avec deux enroulements d'excitation, la mise sous tension alternée duquel permettant d'exercer sur le corps de vanne des forces de réglage agissant dans des directions alternées, le piston de la vanne ayant une position médiane centrée par des ressorts et correspondant à la position de base 0 de la vanne, qui correspond à l'état d'arrêt du vérin correspondant, et dans le cas de laquelle des directions alternées de l'excursion du piston sont attribuées aux positions de fonctionnement alternées (I et II), qui correspondent aux directions d'entraínement alternées du vérin respectif, caractérisée en ce que la vanne (33, 34, 36) est conçue comme vanne à modulation de la largeur d'impulsion, dans le cas de laquelle les enroulements d'excitation peuvent être activés selon une chronologie continue rapide et alternée pour différentes périodes de temps T1 et T2, de sorte que la direction et la valeur de l'excursion du piston de vanne, pour lesquels il convient, pour une position de fonctionnement sélectionnée de la vanne, de régler une section et une résistance d'écoulement définie, sont déterminées par le rapport des temps d'excitation T1 et T2, le rapport T1/T2 = 1 étant attribué à la position de base du piston mobile et la somme T1 + T2 des périodes d'excitation, pendant lesquelles les enroulements d'excitation (38 et 39) sont mis périodiquement sous tension, étant choisie suffisamment petite, de sorte que les amplitudes d'excursion des mouvements du piston de vanne se produisant dans les états d'équilibre effectifs, sont plus petites de manière significative que la course maximale de réglage de celui-ci, la somme des temps de réglage T1 + T2 correspondant à une valeur constante T pouvant être imposée, c'est à dire à une fréquence de modulation fm = 1/T, en ce que, comme courants d'excitation pour les deux enroulements d'excitation, on utilise par ailleurs des courants continus pulsés, dont la fréquence de répétition des impulsions fi est au moins de 10 fois, et de préférence de 50 à 100 fois, plus grande que la fréquence de modulation fm, et en ce que le rapport T1/T2 peut être modifié entre 1/100 et 100/1.
  9. Installation hydraulique selon la revendication 8, caractérisée en ce que la fréquence fm, avec laquelle peuvent être générées les impulsions de modulation des différentes durées T1 et T2, est d'au moins de 200 Hz et est située de préférence entre 400 Hz et 1000 Hz et en ce que la fréquence de répétition des impulsions fi est située entre 5 et 10 kHz.
  10. Installation hydraulique selon l'une des revendications 1 à 9, caractérisée en ce que la vanne de pilotage du levage (14) et l'autre(les autres) vanne(s) de pilotage (33, 34, 36) est(sont) munie(s) respectivement d'un raccord de captage de la charge (x) (57), qui est relié dans la position de base (0) de la vanne respective (14, 33, 34, 36) avec le raccord de retour (T) (53) de la vanne de pilotage respective (14, 33, 34, 36) et dans les positions de fonctionnement alternées (I et II) de la vanne de pilotage respective (14, 33, 34, 36) soit avec l'un des raccords de consommateurs (63) soit avec l'autre des raccords de consommateurs (64) de la vanne de pilotage respective (14, 33, 34, 36), et en ce que ces raccords de captage de la charge (x) (57) sont reliés avec des raccords d'alimentation (58, 61, 69, 71) de respectivement une vanne à altemance (59, 68, 72), qui forment un ensemble de comparaison de la pression, par l'intermédiaire duquel la pression de service respectivement la plus élevée qui a été captée est amenée au raccord de pression (78) d'une balance de pression (79), dont le raccord de pression de référence (81) est branché sur la sortie de pression (51) du groupe de production de pression (52).
  11. Installation hydraulique selon l'une des revendications 1 à 10, caractérisée en ce qu'un bloc de commande (110) formant le boítier pour au moins la vanne de pilotage du levage (14) et de préférence aussi pour d'autres vannes de commande (33, 34, 36) dispose d'une conception en plusieurs couches formées de tôles de segments (1221 à 12214), qui sont brasées ensemble sur leurs surfaces de délimitation longitudinales larges et qui sont munies d'évidements, par l'évolution des contours et par la disposition réciproque desquels sont imposées, à l'intérieur du bloc de commande (110) les formes de sections et les dimensions intérieures de canaux transversaux et de canaux longitudinaux ainsi que de canaux de vannes et de chambres de commande.
  12. Installation hydraulique selon la revendication 11, caractérisée en ce que la "première" tôle de segment extérieure (1221) et d'autres tôles de segments (1222 à 1228) disposées à l'intérieur du bloc de commande (110) sont munies de forures circulaires (1231 à 1238) de même diamètre, qui forment, dans une disposition en alignement réciproque, un canal transversal (132) servant de raccord d'alimentation en pression (P), qui aboutit dans une fente longitudinale (124) de la tôle de segment (1229) placée à la suite dans le sens allant vers l'intérieur, qui forme la conduite d'alimentation en pression (49), qui conduit aux raccords d'alimentation en pression (P) (48) des différentes vannes de commande (11, 13, 34, 36).
  13. Installation hydraulique selon la revendication 11 ou la revendication 12, caractérisée en ce que la "première" tôle de segment extérieure (1221) et d'autres tôles de segments (1222 à 1225) disposées à l'intérieur du bloc de commande (110) sont munies de forures circulaires (1311 à 1315), qui forment, dans une disposition en alignement réciproque, le canal de raccordement de retour (T) (131), qui aboutit dans la conduite de retour (54) délimitée de son côté par des évidements en forme de fentes et à laquelle sont raccordées les vannes de pilotage (14, 33, 34 et 36).
  14. Installation hydraulique selon l'une des revendications 11 à 13, caractérisée en ce que la tubulure de raccordement d'alimentation en pression (P) (48') et/ou la tubulure de raccordement de retour (T) (53') est(sont) brasée(s) dans une section extérieure du canal transversal d'alimentation (P) (123) ou du canal de retour (T) (131) du bloc de commande (110).
EP98107020A 1997-04-20 1998-04-17 Installation hydraulique pour chariot élévateur à fourche Expired - Lifetime EP0872446B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19716442A DE19716442A1 (de) 1997-04-20 1997-04-20 Hydraulik-Installation an einem Gabelstapler-Fahrzeug
DE19716442 1997-04-20

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EP0872446A2 EP0872446A2 (fr) 1998-10-21
EP0872446A3 EP0872446A3 (fr) 2000-05-03
EP0872446B1 true EP0872446B1 (fr) 2003-10-22

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Publication number Priority date Publication date Assignee Title
JP3558861B2 (ja) † 1998-03-16 2004-08-25 日立建機株式会社 トーナメント油路構成装置
DE19909713A1 (de) 1999-03-05 2000-09-07 Linde Ag Steuerventileinrichtung
DE102011116113A1 (de) * 2011-10-15 2013-04-18 Jungheinrich Aktiengesellschaft Flurförderzeug mit einer Arbeitshydraulik
DE102012024647A1 (de) * 2012-12-17 2014-06-18 Jungheinrich Aktiengesellschaft Hydraulische Hubvorrichtung für ein batteriebetriebenes Flurförderzeug
DE102013206319A1 (de) * 2013-04-10 2014-10-16 Deere & Company Hubvorrichtung
US11613453B2 (en) * 2019-08-29 2023-03-28 The Raymond Corporation Variable hydraulic pressure relief systems and methods for a material handling vehicle

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BG37431A1 (en) * 1983-09-27 1985-06-14 Lazarov Hydraulic scheme for tipping lifting device of electrocar for high- lifting
DE3441946A1 (de) * 1984-11-16 1986-05-28 Robert Bosch Gmbh, 7000 Stuttgart Hydraulische steuereinrichtung
US5036886A (en) * 1988-12-12 1991-08-06 Olson Controls, Inc. Digital servo valve system
JPH03159879A (ja) * 1989-11-20 1991-07-09 Toyota Autom Loom Works Ltd 産業車両の荷役制御装置
JP2877257B2 (ja) * 1991-02-05 1999-03-31 三菱重工業株式会社 作業機械の制御装置
DE4140409A1 (de) * 1991-12-07 1993-06-09 Robert Bosch Gmbh, 7000 Stuttgart, De Elektrohydraulische steuereinrichtung
DE4140408A1 (de) * 1991-12-07 1993-06-09 Robert Bosch Gmbh, 7000 Stuttgart, De Elektrohydraulische steuereinrichtung
DE4241846C2 (de) * 1992-12-11 1996-09-26 Danfoss As Hydraulisches System
DE29508394U1 (de) * 1995-05-19 1995-08-03 Heilmeier & Weinlein Elektrohydraulisches Hubmodul

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Publication number Publication date
EP0872446A3 (fr) 2000-05-03
EP0872446A2 (fr) 1998-10-21
DE19716442A1 (de) 1998-10-22
DE59809944D1 (de) 2003-11-27

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