EP0872645B1 - Dispositif d'entraínement électro-hydraulique pour commander à distance un distributeur hydraulique - Google Patents

Dispositif d'entraínement électro-hydraulique pour commander à distance un distributeur hydraulique Download PDF

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Publication number
EP0872645B1
EP0872645B1 EP19980104126 EP98104126A EP0872645B1 EP 0872645 B1 EP0872645 B1 EP 0872645B1 EP 19980104126 EP19980104126 EP 19980104126 EP 98104126 A EP98104126 A EP 98104126A EP 0872645 B1 EP0872645 B1 EP 0872645B1
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EP
European Patent Office
Prior art keywords
signal
slider
electrohydraulic device
electromagnets
joystick
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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.)
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EP19980104126
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German (de)
English (en)
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EP0872645A2 (fr
EP0872645A3 (fr
Inventor
Claudio Bovi
Renato Brevini
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Brevini Hydraulics SpA
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Brevini Hydraulics SpA
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Publication of EP0872645A3 publication Critical patent/EP0872645A3/fr
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • 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
    • F15B13/0401—Valve members; Fluid interconnections therefor
    • F15B13/0402—Valve members; Fluid interconnections therefor for linearly sliding valves, e.g. spool valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • 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
    • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
    • F15B13/043—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves
    • F15B13/0433—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves the pilot valves being pressure control valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • 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
    • F15B13/0442—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 with proportional solenoid allowing stable intermediate positions
    • 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
    • F15B13/0401—Valve members; Fluid interconnections therefor
    • F15B2013/0409—Position sensing or feedback of the valve member

Definitions

  • the present invention relates to an electrohydraulic device for driving and remotely controlling a hydraulic distributor. More particularly, the device according to the present invention is meant to be used in hydraulic systems for actuating user devices with two actuation branches which are selectively connected to a pressurized branch of the hydraulic circuit and to the discharge branch, for example in machines for lifting or moving a load.
  • Hydraulic actuation devices are known for actuating a hydraulic user device with a speed which is independent of the resisting load that affects said hydraulic user device.
  • These devices comprise, for example, as disclosed in EPA no. 97100802.4 in the name of the same Applicant, a distributor which can be actuated so as to connect a user device actuation branch to a pressurized branch of a hydraulic circuit and to connect the other user device actuation branch to a discharge branch of the hydraulic circuit.
  • the hydraulic distributor is provided with a moving slider which moves on command into the chosen position in order to connect one user device or the other to the pressurized branch or to connect them both to the discharge.
  • the slider actuation unit is constituted by a lever, through which the slider is moved along the axis of its own seat, in contrast with the action of a return spring. It is also possible to actuate the slider of the distributor by means of an automatic actuation device.
  • An example of open-loop actuation system uses two proportional valves to actuate the slider; the valves are actuated by means of a joystick and of an electronic control board, which is arranged separately from the body containing the slider.
  • a drawback of this solution is the fact that several electrical cables are required in order to connect the electronic board to the electric valves which are accommodated proximate to the slider.
  • joystick-based control does not allow to adjust the flow-rate/pressure delivered by the electric valves, but only allows to select the electric valve to be actuated.
  • An example of closed-loop actuation system instead uses four valves of the on-off type, with a position transducer adapted to detect the exact position of the slider of the pilot valve, so as to provide a feedback control (closed-loop control) aimed at substantially eliminating any slider positioning error.
  • the electronic board for controlling the valves and the position transducer is accommodated in the same module that contains the slider of the pilot valve.
  • UK Patent Application No. GB 2 248 910 discloses an electrohydraulic device for driving and remotely controlling a hydraulic distributor of a directional valve for pressurizing or connecting to the discharge a pair of user devices comprising two proportional electric valves which are fed by a pressure line, have a discharge line, and are connected respectively to opposite end chambers of a hydraulic distributor adapted to pressurize or connect to the discharge two user devices.
  • the electric valves are driven under the influence of a PWM electrical input current.
  • the aim of the present invention is to provide an electrohydraulic device for driving and remotely controlling a hydraulic distributor which uses the smallest possible number of electric valves, can also be used in an open-loop control system, and allows to minimize the wiring required to connect the electronic part of the device to said electric valves.
  • an object of the present invention is to provide an electrohydraulic device for driving and remotely controlling a hydraulic distributor which can also be used in a closed-loop control system.
  • An object of the present invention is to provide an electrohydraulic device for driving and remotely controlling a hydraulic distributor which can remotely control the flow-rate that can be delivered by the chosen electric valve.
  • Another object of the present invention is to provide an electrohydraulic device for driving and remotely controlling a hydraulic distributor offering a high degree of safety against unintentional manual actuation of the slider of the pilot valve.
  • Another object of the present invention is to provide an electrohydraulic device for driving and remotely controlling a hydraulic distributor having a short slider response time.
  • Another object of the present invention is to provide an electrohydraulic device for driving and remotely controlling a hydraulic distributor having low hysteresis and excellent sensitivity.
  • Another object of the present invention is to provide an electrohydraulic device for driving and remotely controlling a hydraulic distributor which ensures high precision in positioning the slider of the pilot valve and a high repeatability which is not affected by variations of internal parameters such as temperature, friction and elasticity of the spring of the slider.
  • an electrohydraulic device for driving and remotely controlling a hydraulic distributor of a directional valve for pressurizing or connecting to the discharge a pair of user devices, according to claim 1.
  • the electrohydraulic device comprises two proportional electric pressure reducing valves 1, 2 adapted to drive the slider 3 of a hydraulic distributor 6, which allows to pressurize or connect to the discharge two user devices A and B.
  • Figures 1 and 2 illustrate two chambers M and N, arranged respectively to the sides of the slider 3, into which pressure is fed by means of the electric valves 1 and 2 in order to move the slider in one direction or the other according to the user device which is to be driven.
  • the electric valves 1 and 2 are fed with a pressure which is introduced through a line P and the discharges thereof are collected in a discharge line T.
  • Figure 1 also schematically illustrates a control block 5a for driving the electric valves 1 and 2 by means of an electric signal that originates from control means (not shown), which are conveniently constituted for example by a joystick and are arranged remotely with respect to the hydraulic distributor 6.
  • control means not shown
  • the electric signal arriving from the joystick has the purpose of providing proportional control of the hydraulic pressure that is generated by the two electric valves 1 and 2, energizing magnets 11 and 12, respectively, of the electric valves.
  • Figure 1 is a view of the electrohydraulic device in its first embodiment, i.e., in the open-loop configuration, while Figure 2 is a view of the device in the closed-loop configuration.
  • control block 5b receives a feedback signal which arrives from a transducer for the position of the slider 3.
  • the transducer is constituted for example by a differential transformer 7, in which a feeler 8 is connected to the magnetic core 10 of the transformer.
  • the feeler is conveniently constituted by a rod which is constantly in contact with the end of the slider 3, on the side of the chamber M, so as to detect at all times the position of the slider 3 and feed it back to the control block 5b.
  • the electrohydraulic device according to the present invention can of course be arranged both at the chamber M and at the chamber N without any constructive modification.
  • Figures 1 and 2 also illustrate an actuation lever 9, by which it is possible to manually move the slider 3. To prevent the possibility of unintentional activation, the actuation lever 9 can be removed.
  • FIG. 3 to 7 instead illustrate in detail the electronic system meant to actuate the electric valves 1 and 2 both in the open-loop configuration and in the closed-loop configuration.
  • the reference numeral 15 designates voltage stabilizing means, which are conveniently constituted by a high-frequency oscillator which stabilizes the average voltage applied to the electromagnets 11 and 12 of the proportional electric valves 1 and 2.
  • the signal in output from the high-frequency oscillator 15 is fed to a logic gate 16 (AND gate) whose second input is constituted by a signal which is output by an operational amplifier 17 (comparator).
  • the signal in output from the logic gate 16 drives a MOSFET 18 controlling the electromagnet 11 of the electric valve 1.
  • a second logic gate 19 for the second electric valve 2 and, therefore for the corresponding electromagnet 12, a second logic gate 19, a second operational amplifier 20 (comparator) and a second MOSFET 21 are provided.
  • the operational amplifier 17 has a first inverting input receiving an output signal from an oscillator 22 (80-200 Hz) with a trimmer for setting the frequency.
  • the purpose of the amplifier is to supply a variable current to the activated electromagnet.
  • a signal from an amplifier 23 of the proportional-integral type is instead sent to the non-inverting input of the operational amplifier 17.
  • the signal entering the proportional-integral amplifier 23 is the result of a plurality of signals which arrive at an adder node 24.
  • the adder node 24 receives a first signal constituted by the reference signal Rif which arrives from the control joystick and is processed appropriately so as to obtain a signal Rif 1.
  • the signal Rif 1 is obtained so that it is positive for values that are higher than the voltage used as zero (neutral position of the joystick) and can thus drive the electromagnet 11 of the proportional valve 1.
  • This processing occurs in a block 25.
  • a maximum-value trimmer 26 is arranged after the block 25 and has the purpose of setting the maximum value of the current of the electromagnet 11.
  • a minimum-value current trimmer 27 is instead meant to supply a minimum initial current value in order to overcome the resisting force of the spring 4 of the slider 3.
  • the adder node 24 thus adds the current signal, limited by the trimmer 26, and the minimum-current signal supplied by the trimmer 27, and subtracts from this sum a signal corresponding to the detected current of the electromagnet 11.
  • Detection of the current of the electromagnet 11 occurs by means of a current signal amplifier 28 and of a filter 29.
  • the signal produced in the adder node 24 is therefore the signal that is sent to the non-inverting input of the operational amplifier 17.
  • Figure 3 illustrates a second reference signal processing block 30, a second adder node 31, a second maximum-current trimmer 32 and a second threshold current trimmer 33.
  • the signal in output from the second adder node 31 is amplified by a second amplifier of the proportional-integral type 34, whose output constitutes a first non-inverting input of the operational amplifier 20; the second inverting input of said amplifier is a signal that arrives from a second oscillator 35 having a trimmer for setting the frequency.
  • Figure 4 illustrates the second embodiment of the electronic system of the device according to the invention, in which closed-loop control of the position of the slider 3 is achieved by means of the transducer 7 and the feeler 8.
  • Figure 5 is a view of the method for obtaining a signed position error signal, which is then used in the circuit portion shown in Figure 4. Accordingly, the block diagram of Figure 5 is described first.
  • a low-voltage stabilized sine-wave oscillator 35 supplies the primary winding 36 of the differential transformer 7, in which the voltage on the secondary windings 37 and 39 is a function of the position of the magnetic core 10 and is rectified and amplified, in a conditioning device 38, into a voltage signal which can vary over a given voltage interval for the maximum stroke, the minimum stroke and the neutral position of the slider 3.
  • the AC voltage read on the secondary windings 37 and 39 arranged in series is then amplified and rectified in the conditioning device 38 and added to the value of the neutral position voltage of the joystick.
  • the signal Rif arriving from the joystick is filtered by an RC network 40 and is locked by means of a resistor to the neutral position voltage, block 41, in order to maintain the slider 3 in the neutral position if the control signal from the joystick is interrupted.
  • the error signal from the adder node 42 is amplified by an amplifier 43 of the proportional-integral type and constitutes the signed position error signal.
  • the signal is used as reference for the loop for controlling the current of the electromagnets, shown in Figure 4.
  • An absolute position error is extracted from the signed position error E by means of a processing block 44, from which the absolute position error signal
  • the signal produced by the adder node 45 is therefore the current error signal obtained by subtracting the amplified and filtered current signal from the absolute position error signal.
  • the signal in output from the adder node 45 is then sent to a proportional-integral amplifier 46, whose output is the inverting input for an operational amplifier 47, the non-inverting input whereof is constituted by a signal arriving from an oscillator 48.
  • the electromagnets 11 and 12 are never driven simultaneously; for this purpose, two comparators 49 and 50 are provided, the input of which is the signed position error signal E and the neutral reference signal Rif neutro of the joystick, so as to activate the chosen electromagnet as a function of the sign of the slider position error E, detected by means of the position transducer 7.
  • the instantaneous value changes at the frequency of the oscillator 48 (at low frequency), so as to keep the magnetic core 10 under constant oscillation, avoiding the problems linked to initial separation friction.
  • Figure 6 illustrates the logic system of the safeties of the electronic part of the device according to the invention.
  • Said figure illustrates a first window comparator 8, whose task is to monitor the position error arriving from the comparator node 42 of Figure 5. If the error E remains high in absolute value for longer than a given preset time, set by a delay device 55, the device enters the safe mode. The controls are disabled and the output driving transistor 56, which normally actuates an electric valve 57 for connection to the discharge, is switched off.
  • a second window comparator 57 determines whether the position reference signal Rif is or not within acceptable limits, i.e., whether it is not lower than the minimum allowable value and not higher than the maximum allowable value. If one of these two abnormal situations occurs, the window comparator 57 locks off the system.
  • the electronic system described so far is integrated in the housing of the hydraulic distributor, thus minimizing the wiring.
  • the figure illustrates three mutually identical schematic portions, which are dedicated respectively to actuation along three Cartesian coordinated axes x, y and z.
  • Power is supplied to the joystick circuit from a DC source with a voltage which can vary between 10 and 30V and supplies the circuits of the joystick after passing through a noise filter and a circuit for protecting against polarity reversal.
  • a reference source 60 supplies a stabilized DC voltage ensuring a constant output which is exclusively a function of the position and is not affected by the construction tolerance of the potentiometers of the joystick, which will be described hereinafter.
  • the reference numerals 61 designate polarity switches, while the reference numerals 62 designate the respective potentiometers for the three coordinated axes.
  • Said potentiometers supply in output a voltage which is proportional to the movement of the lever of the joystick (not shown), which is then limited by suitable trimmers 63 in order to limit the maximum flow-rate of oil to the electric valves 1 and 2.
  • the potentiometers 62 have a central neutral region with zero resistance, so that when the actuation lever is in the inactive position the output control voltage has an assuredly unique value (neutral value of the control voltage) which is not affected by any instabilities of the inactive position.
  • Additional trimmers 64 are provided in order to adjust the acceleration ramp, i.e., the relation between the movement of the lever of the joystick and the output voltage.
  • the signal in output from the trimmer 64 is sent to an adder node 65 and then to an amplifier 66.
  • the signal in output from the joystick is differential (Rif+, Rif-) so as to allow to avoid the influence of live voltage drops and of noise: in this case, therefore, two conductors dedicated to the output signal are used.
  • the positioning of the slider 3 of the distributor 6 is driven and controlled remotely by the joystick, which has its own electronic system which combines with the electronic control board that is integrated in the body that accommodates the slider 3.
  • the electric output signal of the joystick energizes the electromagnets 11 and 12 of the electric proportional valves and said electric valves, supplied by the low-pressure line P, generate a pressure which is proportional to the electric signal arriving from the joystick; the pressure moves the slider 3 to pressurize or connect to the discharge the chosen user device.
  • the joystick provides in output a voltage which can vary between a minimum value and a maximum value, with an intermediate value corresponding to a zero hydraulic flow rate on the user devices A and B.
  • the output signal of the joystick can be used in two different modes: in closed-loop mode and in open-loop mode.
  • the electric signal emitted by the joystick is compared with the signal of the position transducer 7, so as to obtain the position of the slider 3 as a function of the joystick control voltage, thus eliminating any imprecisions that may be present in the electric valves or in the mechanical system for moving the slider.
  • the pressure of the actuation oil (pressure line P) is a function of the energization current of the electromagnets 11 and 12 and the position of the slider 3 is an almost linear function of the current.
  • the outlets U of the electric valves 1 and 2 connect the chambers M and N to the discharge T: in this inactive configuration, the slider 3 moves into the central position and the two users A and B are connected to the discharge.
  • the voltage in output from the transducer is compared in the node 42 with the electric reference signal Rif arriving from the joystick and the difference between the two signals is amplified by the amplifier 43 and used as a signed position error signal E, which is used as reference for the control loop of the current of the electromagnets 11 and 12 (see figures 4 and 5).
  • the two electromagnets 11 and 12 are never driven simultaneously: the comparators 49 and 50 are used to select one or the other of the two electromagnets, depending on the sign of the position error E.
  • the energization current of the electromagnets 11 and 12 is also detected (this detection is also performed in the open-loop configuration described hereinafter).
  • the amplifier 28 used for this detection acquires only at periodic intervals the actual current of the electromagnet and the missing part of the current is reconstructed by means of the RC circuit 29, having the same time constant as the L/R coil.
  • the value of the current thus detected is compared in the node 45 with the absolute position error
  • the signal in output from the comparator 47 (square wave) activates and deactivates the involved electromagnet 11 or 12.
  • the only control loop that is present is the one related to the activation current of the two electromagnets 11 and 12.
  • the input signal Rif arriving from the joystick follows two separate but mirror-symmetrical paths for the two electromagnets 11 and 12.
  • the processing performed on the signal in the blocks 25 and 30 causes the first block to have, as output, a signal Rif 1 which is positive for values that are higher than the voltage corresponding to the neutral voltage region of the joystick, and is therefore capable of activating the electromagnet 11, while it causes the second block to have as output a signal Rif 2 which is positive for voltage values that are lower than the neutral voltage value (inactive position of the joystick control rod), so as to activate the electromagnet 12.
  • the signals Rif 1 and Rif 2 are then compared respectively with the detected value of the current of the electromagnets, nodes 24 and 31, and the resulting difference signals (current error signals) are respectively compared with the output voltages of the low-frequency oscillators 22 and 35 to then supply the electromagnets 11 and 12 of the proportional electric valves 1 and 2.
  • oscillators 15 are provided for stabilizing the supply voltage so as to make the operation of the device independent of the particular external supply voltage.
  • the generation of the electric output signal of the joystick can follow in a substantially linear manner the position of the actuation lever of said joystick, with a neutral central region corresponding to the inactive position of the actuation lever, or the output signal can be linked adjustably (by means of the trimmers 64) to the movement of the actuation lever; i.e., the slope of the output signal of the joystick can be altered at will.
  • the voltage value of the output signal can be changed though the same stroke is performed with the joystick actuation lever.
  • the electronic system of the joystick includes a device for protection in case of lack of supply voltage; if this case occurs, the output signal is automatically placed in a high-impedance condition in order to make the slider 3 return to the neutral position.
  • a device for protection against short circuits on the output a device for protection against the breakdown of a potentiometer 62, and a device for protection against power supply noise.
  • the device for protection against power supply noise includes a double filtering system to limit overvoltages.
  • a varistor contains high-value pulsed voltages, while an LC circuit with a high-value capacitor limits the overvoltages having a modest amplitude but a longer duration (sudden disconnection of loads, opening and closing of circuits).
  • the pressure in input to the electric valve 1 is always constant, while the pressure at the outlet U is exclusively a function of, and proportional to, the amount of current acting on the electromagnet 11 at that time.
  • the reduced pressure of the outlet U passes, by means of the line F, into the chamber M, in which it acts on the area of the slider 3, pushing the slider to the left in the drawing and thus allowing the flow of pressure towards the user device A.
  • the chamber N by means of the connection line Z, is connected to the outlet U of the electric valve 2, which connects it to the discharge T by means of its position 300.
  • the position 400 of the electric valve 2 moves into the position 300, allowing to connect the outlet U to the pressure line P.
  • the reduced pressure of the outlet U then passes, through the line Z, to the chamber N, pressurizing it and thus acting on the slider 3 so as to move it to the right in the figure, thus allowing the inflow of pressure to the user device B of the distributor 6.
  • the chamber M is connected to the discharge T.
  • the probe 8 of the position transducer 7 detects, in each instant, the position of the slider 3 and converts it into an electric voltage, which is compared to the reference voltage arriving from the joystick, as explained hereinafter.
  • the fault reporting system allows to lock the device very quickly, while indicating visually the fault state.
  • the electrohydraulic device according to the present invention fully achieves the intended aim, since it allows to drive and control remotely a hydraulic distributor, moving the slider according to requirements so as to activate or deactivate the user devices connected to the distributor.
  • Remote control by means of the joystick allows to actuate the two proportional electric valves, which in turn generate a hydraulic pressure which is proportional to the electric signal sent by the joystick, in order to actuate the movement of the slider.
  • the duty cycle of the low modulating frequency remains constant, while in the previously described case it varies according to the current and therefore with high current values the ability of the magnetic core 10 to vibrate may disappear.
  • the above described embodiment allows to independently adjust the modulating frequencies for the two electromagnets 11 and 12, so as to adapt the frequency to the characteristics of the electric valve and of the hydraulic circuit.
  • the materials employed may be any according to requirements and the state of the art.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Servomotors (AREA)
  • Mechanical Control Devices (AREA)
  • Valve Device For Special Equipments (AREA)
  • Magnetically Actuated Valves (AREA)

Claims (15)

  1. Dispositif électro-hydraulique pour entraíner et commander à distance un distributeur hydraulique (6) d'une valve directionnelle pour mettre en pression ou connecter à la décharge deux dispositifs utilisateurs (A, B) comprenant :
    deux valves piézo-électriques proportionnelles (1, 2), qui sont alimentées par une ligne de pression (P), ont une ligne de décharge (T) et sont connectées hydrauliquement respectivement à des chambres d'extrémité opposées (M, N) d'un distributeur hydraulique (6) adapté pour mettre en pression ou connecter à la décharge (T) deux dispositifs utilisateurs (A, B) ;
    des moyens de commande à distance adaptés pour générer un signal de commande électrique pour exciter des électroaimants (11, 12) desdites valves piézo-électriques (1, 2) ; et
    un circuit électronique (5a, 5b) adapté pour commander et régler le courant d'excitation desdits électroaimants (11, 12) en fonction dudit signal de commande électrique ; ledit courant d'excitation entraínant lesdits électroaimants (11, 12) pour l'alimentation sélective desdits chambres (M, N) avec une pression prédéterminée ou leur connexion à la décharge à travers lesdites valves piézo-électriques (1, 2) de manière à déplacer le bloc coulissant (3) dudit distributeur (6) proportionnellement audit courant d'excitation ;
       caractérisé en ce qu'il comprend un transducteur de position (7) adapté pour détecter la position du bloc coulissant (3) dudit distributeur (6) et pour la convertir en signal de tension analogique et ledit circuit électronique (5a, 5b) comprend des moyens pour détecter le courant desdits électroaimants (11, 12) et des moyens de comparaison (45) adaptés pour comparer un signal d'erreur de position du bloc coulissant (E) avec le signal de sortie desdits moyens pour détecter le courant des électroaimants, ledit circuit électronique (5a, 5b) étant incorporé dans le corps qui loge ledit distributeur hydraulique (6).
  2. Dispositif électro-hydraulique selon la revendication 1, caractérisé en ce que ledit circuit électronique (5a, 5b) comprend des moyens (24, 31) pour comparer le courant détecté desdits électroaimants avec un signal de commande (RIF) arrivant des moyens de commande à distance de manière à générer un signal d'erreur de courant.
  3. Dispositif électro-hydraulique selon la revendication 1, caractérisé en ce que ledit circuit électronique . (5a, 5b) comprend des moyens de comparaison adaptés pour comparer ledit signal de tension analogique avec ledit signal de commande (RIF) qui arrive des moyens de commande à distance de manière à générer ledit signal d'erreur de position du bloc coulissant (E), ledit signal d'erreur de position (E) étant réinjecté sur lesdites valves piézo-électriques (1, 2).
  4. Dispositif électro-hydraulique selon la revendication 3, caractérisé en ce qu'il comprend des moyens d'oscillateur basse tension (22, 35) adaptés pour générer un signal qui peut être comparé avec ledit signal d'erreur de courant de manière à commander lesdits électroaimants (11, 12).
  5. Dispositif électro-hydraulique selon la revendication 3, caractérisé en ce que lesdits moyens pour détecter le courant desdits électroaimants comprennent un amplificateur (28) avec un filtre connecté en cascade (29).
  6. Dispositif électro-hydraulique selon une ou plusieurs des revendications précédentes, caractérisé en ce que ledit circuit électronique (5a, 5b) comprend un oscillateur stabilisateur de tension (15) qui est adapté pour stabiliser la tension aux bornes desdits électroaimants (11, 12).
  7. Dispositif électro-hydraulique selon la revendication 1, caractérisé en ce que ledit transducteur de position (7) comprend un transformateur différentiel (7) ayant un noyau magnétique (10) et auquel un palpeur (8) est connecté, ledit palpeur (8) étant destiné à être en contact, à tout instant, avec ledit bloc coulissant (3) pour détecter sa position.
  8. Dispositif électro-hydraulique selon la revendication 3, caractérisé en ce qu'il comprend un comparateur à fenêtre (8) pour le signal d'erreur de position du bloc coulissant (E) de manière à maintenir le mouvement dudit bloc coulissant (3) dans des limites prédéterminées.
  9. Dispositif électro-hydraulique selon la revendication 1, caractérisé en ce qu'il comprend un deuxième comparateur à fenêtre (57) pour le signal de commande provenant desdits moyens de commande à distance, de manière à maintenir la valeur de tension dudit signal de commande dans des valeurs prédéterminées.
  10. Dispositif électro-hydraulique selon la revendication 1, caractérisé en ce qu'il comprend un circuit de protection contre le bruit d'alimentation électrique.
  11. Dispositif électro-hydraulique selon les revendications 8 et 9, caractérisé en ce qu'il comprend une valve piézo-électrique pour connecter le dispositif à la décharge, adapté pour désactiver le dispositif à la suite d'un signal d'erreur provenant desdits comparateurs à fenêtre (8, 57).
  12. Dispositif électro-hydraulique selon la revendication 1, caractérisé en ce que lesdits moyens de commande à distance comprennent un manche à balai ayant un circuit électronique qui lui est propre.
  13. Dispositif électro-hydraulique selon la revendication 12, caractérisé en ce que ledit manche à balai comprend, pour le mouvement suivant chacun des trois axes cartésiens de coordonnées, un commutateur de polarité (61) pour inverser le mouvement, un potentiomètre (62) avec une tension de sortie qui est proportionnelle au mouvement du levier de commande dudit manche à balai et un trimmer (63) pour ajuster le signal de commande de sortie de manière à limiter le débit maximal de ladite ligne de pression (P) desdits valves piézo-électriques (1, 2).
  14. Dispositif électro-hydraulique selon la revendication 12, caractérisé en ce que ledit manche à balai comprend en outre un trimmer (64) pour ajuster la rampe d'accélération dudit signal de commande de sortie de manière à varier la tension fournie comme sortie pour un même mouvement dudit levier de commande.
  15. Dispositif électro-hydraulique selon la revendication 12, caractérisé en ce que le signal de commande de sortie (RIF) dudit manche à balai est un signal de tension différentielle.
EP19980104126 1997-04-14 1998-03-09 Dispositif d'entraínement électro-hydraulique pour commander à distance un distributeur hydraulique Expired - Lifetime EP0872645B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT97MI000862A IT1291564B1 (it) 1997-04-14 1997-04-14 Dispositivo elettroidraulico per il pilotaggio ed il controllo a distanza di un distributore idraulico
ITMI970862 1997-04-14

Publications (3)

Publication Number Publication Date
EP0872645A2 EP0872645A2 (fr) 1998-10-21
EP0872645A3 EP0872645A3 (fr) 2000-04-05
EP0872645B1 true EP0872645B1 (fr) 2003-11-12

Family

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Country Link
EP (1) EP0872645B1 (fr)
DE (1) DE69819587T2 (fr)
DK (1) DK0872645T3 (fr)
IT (1) IT1291564B1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10034033A1 (de) 2000-07-13 2002-01-24 Nass Magnet Gmbh Magnetventil
DE102005032588A1 (de) 2005-07-11 2007-01-25 Bosch Rexroth Ag Elektrohydraulische Steuerungsvorrichtung
DE102006029623A1 (de) * 2006-06-28 2008-01-03 Robert Bosch Gmbh Elektrohydraulisches System, sowie Vorrichtung und Verfahren zum Betätigen eines solchen
CN102384118B (zh) * 2011-08-31 2013-05-08 中联重科股份有限公司 电液比例阀调速控制方法、装置、系统以及工程机械设备
CN102392914B (zh) * 2011-10-31 2013-01-23 常德中联重科液压有限公司 电液比例方向阀控制方法及其控制系统
DE102012024333B4 (de) * 2012-12-13 2022-11-03 Festo Se & Co. Kg Ventileinrichtung

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2132717A1 (de) * 1971-07-01 1973-01-18 Bosch Gmbh Robert Ansteuerschaltung fuer magnetventile hoher schaltgeschwindigkeit, insbesondere einer hydraulischen stelleinrichtung
DE3245259A1 (de) * 1982-12-07 1984-06-07 Mannesmann Rexroth GmbH, 8770 Lohr Elektrohydraulisches wegeventil
US4659969A (en) * 1984-08-09 1987-04-21 Synektron Corporation Variable reluctance actuator having position sensing and control
JP2658432B2 (ja) * 1988-12-01 1997-09-30 ダイキン工業株式会社 油圧制御装置
GB9018771D0 (en) * 1990-08-28 1990-10-10 Trans Nordic Hydraulics Limite Electrical operation of hydraulic control spool valves
AT400634B (de) * 1992-12-09 1996-02-26 Hoerbiger Ventilwerke Ag Proportionalventil mit wegaufnehmer

Also Published As

Publication number Publication date
EP0872645A2 (fr) 1998-10-21
DE69819587D1 (de) 2003-12-18
DE69819587T2 (de) 2004-09-16
EP0872645A3 (fr) 2000-04-05
IT1291564B1 (it) 1999-01-11
DK0872645T3 (da) 2004-02-16
ITMI970862A1 (it) 1998-10-14

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