EP0471884A1 - Electrohydraulic servovalve - Google Patents

Electrohydraulic servovalve Download PDF

Info

Publication number
EP0471884A1
EP0471884A1 EP19900116279 EP90116279A EP0471884A1 EP 0471884 A1 EP0471884 A1 EP 0471884A1 EP 19900116279 EP19900116279 EP 19900116279 EP 90116279 A EP90116279 A EP 90116279A EP 0471884 A1 EP0471884 A1 EP 0471884A1
Authority
EP
European Patent Office
Prior art keywords
spool
pressure
servo valve
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.)
Granted
Application number
EP19900116279
Other languages
German (de)
French (fr)
Other versions
EP0471884B1 (en
Inventor
Herbert Handte
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Moog GmbH
Original Assignee
Moog GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Moog GmbH filed Critical Moog GmbH
Priority to EP19900116279 priority Critical patent/EP0471884B1/en
Priority to DE59010152T priority patent/DE59010152D1/en
Priority to JP20564991A priority patent/JPH0626501A/en
Priority to US07/749,216 priority patent/US5165448A/en
Publication of EP0471884A1 publication Critical patent/EP0471884A1/en
Application granted granted Critical
Publication of EP0471884B1 publication Critical patent/EP0471884B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • F15B13/042—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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86574—Supply and exhaust
    • Y10T137/86582—Pilot-actuated
    • Y10T137/8659—Variable orifice-type modulator
    • Y10T137/86598—Opposed orifices; interposed modulator
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86574—Supply and exhaust
    • Y10T137/86582—Pilot-actuated
    • Y10T137/86614—Electric

Definitions

  • the invention relates to an electrohydraulic proportional or servo valve according to the preamble of claim 1.
  • Control loops are increasingly being used by machine manufacturers to increase product quality and the degree of automation.
  • a typical application is the electro-hydraulic position control loop.
  • the proportional valve has an important function. It must convert an electrical signal quickly and accurately into an appropriate flow or pressure. In these applications, it is particularly important to keep the controlled variable within narrow tolerances. Therefore, a strictly linear characteristic between the electrical control signal and the flow must be requested.
  • proportional valves are characterized by the fact that constructive improvements were aimed at minimizing the so-called dead band range of the valve characteristic.
  • dead band range of the valve characteristic.
  • the present invention has for its object to provide a linear servo valve of the type mentioned, in which, despite good linearity, a standstill of the consumer is guaranteed in the rest position.
  • the present invention makes use of the knowledge that it is not so important to make the valve itself linear in terms of its mechanical structure, but that a linear valve can also be achieved by deliberately choosing a non-linear valve which again uses an electrical circuit is made linear.
  • Valves with a mechanical coverage area ensure a safe standstill of the consumer under load, since they reliably separate the pressure outlet channel from the pressure inlet channel even with the usual manufacturing tolerances when the control piston is in the neutral position.
  • the proportional valve has a cylinder 1 with a central pressure inlet channel 2, two pressure outlet channels 3 and 4 arranged offset in the axial direction and a return channel 5 which is connected to the supply tank.
  • a control piston 6 is mounted between two driver pistons 22.
  • the end faces 7 of the driver pistons 22 can be acted upon by a control pressure in the axial direction via the control chambers 9 and 10.
  • a pair of piston rings 11 are formed on the control piston above the two pressure outlet channels 3 and 4, respectively.
  • the control piston has annular recesses between the piston rings 11 so that the hydraulic fluid can flow around the piston better.
  • Corresponding (annular) chambers are formed in the opposite sections of the cylinder wall. The pressure on the piston rings 11 therefore acts on the entire circumference of the piston surface.
  • the two pressure outlet channels 3, 4 have a diameter a, which corresponds to the thickness of the annular chambers.
  • the two piston rings 11 are spaced apart in the axial direction such that the total thickness D of the two piston rings is greater than the thickness of the annular chambers (a) or the diameter of the pressure outlet openings 3 and 4 on the inside of the cylinder wall. Half of the difference between the total thickness D and the thickness of the annular chambers or the diameter of the pressure outlet channels (a) should define the positive overlap x.
  • the maximum deflection of the control piston 6 from the rest position is to be denoted by y.
  • the pressure-free outer spaces of the cylinder 1 are connected to one another via a compensating line 12 and the common return duct (5).
  • the control piston 6 is axially centered in the valve housing by means of two springs 8, which also act on the end faces 7 of the driver piston 22. With the control piston 6, an electrical position sensor 13 is connected in an axial extension, which via an elek known from the prior art tric position control loop 20 is fed back to a torque motor 14.
  • the position control loop and compensation circuit 21 according to the invention are located in an electrically insulated part of the valve housing.
  • the armature 15 of the torque motor 14 acts directly on the baffle plate 16 of a nozzle 17 baffle plate 16 system.
  • the control rooms 9 and 10 have a bypass channel 18 and an electrically operated valve 19 located in this channel in order to be connected to one another when the valve is open.
  • the circuit shows a preferred embodiment of the compensation circuit.
  • the circuit consists of an inverting amplifier with an input resistor R and a feedback circuit consisting of three feedback branches which act on the negative input of the operational amplifier.
  • One of these feedback branches only consists of an adjustable ohmic resistor R 3 , the other two each consist of a series connection of an adjustable voltage source U 1 or U 2 , a diode D 1 and D 2 and an adjustable resistor R 1 or R 2 .
  • the diodes D 1 and D 2 are switched in the reverse direction with respect to the polarities of the voltage sources U 1 and U 2 .
  • Fig. 3 the relationship between the input and the output signal is shown graphically.
  • the graph is defined in sections by the equations given above.
  • the slopes of the straight sections are determined by the ratios of the feedback resistors Ri, R 2 , and R 3 to the input resistance R. The lower the ratio, the flatter the respective straight line section.
  • variable voltage sources U and U 2 are decisive for the position of the break points of the non-linearity. Increasing or decreasing the voltage shifts the respective inflection point in the direction of the positive and negative Y-axis of the graph in Fig. 3.
  • the return duct with the resistor R 3 that is always effective, is specified in dependence on the output signal in the above- Way connected in parallel to either resistor R 1 or R 2 .
  • valve 19 located in the bypass channel 18 opens when the power supply is interrupted, the control chambers 9, 10 are hydraulically short-circuited. As a result, an existing pressure difference in the control chambers is immediately equalized and the return springs 8 move the control piston 6 into the area of positive overlap. Here the absolute safe standstill of the consumer is guaranteed, since no leakage currents can occur in the overlap area. This takes into account the need for security.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Servomotors (AREA)

Abstract

The invention relates to an electrohydraulic servo valve with a proportional relationship between the electric actuating signal and the deflection of the spool of the servo valve, the servo valve having a cylinder and a spool mounted therein, and the spool being situated on its two ends in pressurisable control chambers so that the spool is deflected out of its neutral position in the case of a pressure difference in these two control chambers, the cylinder having a central pressure inlet passage and two pressure outlet passages arranged offset in the axial direction, which are closed by the spool when it is in its neutral position and, when the spool is deflected, are partially or completely opened in order to free a passage cross-section dependent on the position of the spool between one of the pressure outlet passages and the pressure inlet passage, the pressure difference in the control chambers being produced by the electric actuating signal. The servo valve is characterised in that the spool is dimensioned in such a way that it begins to open one or the other pressure outlet channel only at a predetermined axial deflection (x) out of its neutral position (positive overlap) and in that an electric compensation circuit is provided to compensate the nonlinearity, caused by the positive overlap, between the electric control signal and the deflection of the spool, and in that the two control chambers can be connected to one another via a bypass passage by means of an electrically actuated valve situated in the passage in order to compensate the pressure, and in that this valve is designed in such a way that it opens in the deenergised condition. <IMAGE>

Description

Die Erfindung bezieht sich auf ein elektrohydraulisches Proportional- oder Servoventil nach dem Oberbegriff des Anspruchs 1.The invention relates to an electrohydraulic proportional or servo valve according to the preamble of claim 1.

Regelkreise werden von Maschinenherstellern zunehmend zur Steigerung von Produktqualität und des Automatisierungsgrades eingesetzt. Eine typische Anwendung ist der elektrohydraulische Lageregelkreis.Control loops are increasingly being used by machine manufacturers to increase product quality and the degree of automation. A typical application is the electro-hydraulic position control loop.

Eine wichtige Eunktion hat dabei das Proportionalventil. Es muß ein elektrisches Signal schnell und genau in einen entsprechenden Durchfluß oder Druck umwandeln. Insbesondere ist es bei diesen Anwendungen wichtig, die Regelgröße in engen Toleranzen zu halten. Deshalb ist eine streng lineare Kennlinie zwischen dem elektrischen Steuersignal und dem Durchfluß zu fordern.The proportional valve has an important function. It must convert an electrical signal quickly and accurately into an appropriate flow or pressure. In these applications, it is particularly important to keep the controlled variable within narrow tolerances. Therefore, a strictly linear characteristic between the electrical control signal and the flow must be requested.

Die Entwicklung der Proportionalventile ist dadurch gekennzeichnet, daß konstruktive Verbesserungen zum Ziel hatten, den sogenannten Totbandbereich der Ventilkennlinie zu minimieren. Dabei trat zwangsweise die Problematik auf, daß bei Ventilen, bei denen der Totbandbereich zugunsten der Linearität gering gehalten wurde, Leckströme aufgrund der mechanischen Fertigungstoleranzen auftreten.The development of proportional valves is characterized by the fact that constructive improvements were aimed at minimizing the so-called dead band range of the valve characteristic. Inevitably, the problem arose that in valves in which the dead band area was kept small in favor of linearity, leakage currents occur due to the mechanical manufacturing tolerances.

Genaue Linearität und Sicherheit in der neutralen Stellung sind in Servoventilen wegen der angesprochenen Leckströme nicht vereinbar. Die geforderte Sicherheit kann nur mit zusätzlichen Mitteln realisiert werden.Exact linearity and safety in the neutral position are not compatible in servo valves due to the leakage currents mentioned. The required security can only be achieved with additional means.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, ein lineares Servoventil der eingangs genannten Art anzugeben, bei dem trotz guter Linearität ein Stillstand des Verbrauchers in der Ruhestellung gewährleistet ist.The present invention has for its object to provide a linear servo valve of the type mentioned, in which, despite good linearity, a standstill of the consumer is guaranteed in the rest position.

Diese Aufgabe wird, gemäß vorliegender Erfindung durch die Merkmale des Anspruchs 1 gelöst.This object is achieved according to the present invention by the features of claim 1.

Die vorliegende Erfindung nutzt die Erkenntnis, daß es nicht so wichtig ist, das Ventil selbst von seinem mechanischen Aufbau linear zu gestalten, sondern daß ein lineares Ventil auch dadurch erreicht werden kann, daß man bewußt ein nichtlineares Ventil wählt, das mit einer elektrischen Schaltung wieder linear gemacht wird.The present invention makes use of the knowledge that it is not so important to make the valve itself linear in terms of its mechanical structure, but that a linear valve can also be achieved by deliberately choosing a non-linear valve which again uses an electrical circuit is made linear.

Ventile mit einem mechanischen Überdekkungsbereich gewährleisten einen sicheren Stillstand des unter Last stehenden Verbrauchers, da sie auch bei den üblichen Fertigungstoleranzen den Druckauslaßkanal zuverlässig von dem Druckeinlaßkanal trennen, wenn sich der Steuerkolben in der neutralen Stellung befindet.Valves with a mechanical coverage area ensure a safe standstill of the consumer under load, since they reliably separate the pressure outlet channel from the pressure inlet channel even with the usual manufacturing tolerances when the control piston is in the neutral position.

Dadurch erhält das Ventil aber eine nicht lineare Charakteristik. Durch die elektrische Kompensationsschaltung wird die Linearität wieder vollständig erreicht, ohne aber den angesprochenen Sicherheitsvorteil aufgeben zu müssen.This gives the valve a non-linear characteristic. The linearity is completely achieved again by the electrical compensation circuit, but without having to give up the safety advantage mentioned.

Mit dem zusätzlichen Bypasskanal und dem darin gelagerten Elektroventil wird weiterhin sichergestellt, daß das Servoventil sehr schnell, beispielsweise bei Stromausfall sofort in seine Ruhestellung übergeht, in der die Last absolut stillsteht.With the additional bypass channel and the electrovalve stored in it, it is further ensured that the servo valve switches to its idle position very quickly, for example in the event of a power failure, in which the load is absolutely stationary.

Im folgenden wird die Erfindung anhand einer in der Zeichnung dargestellten Ausführungsform erläutert.

  • Fig. 1 zeigt ein Schnittbild eines Proportionalventils zweistufiger Bauart;
  • Fig. 2 zeigt eine bevorzugte Ausführung der Kompensationsschaltung.
  • Fig. 3 zeigt den Zusammenhang zwischen Ausgangs- und Eingangsspannung der Kompensationsschaltung.
The invention is explained below with reference to an embodiment shown in the drawing.
  • Fig. 1 shows a sectional view of a proportional valve of two-stage design;
  • Fig. 2 shows a preferred embodiment of the compensation circuit.
  • Fig. 3 shows the relationship between the output and input voltage of the compensation circuit.

Das Proportionalventil weist einen Zylinder 1 mit einem mittigen Druckeinlaßkanal 2, zwei in axialer Richtung versetzt angeordnete Druckauslaßkanäle 3 und 4 sowie einen Rückführkanal 5, der mit dem Versorgungstank verbunden ist, auf.The proportional valve has a cylinder 1 with a central pressure inlet channel 2, two pressure outlet channels 3 and 4 arranged offset in the axial direction and a return channel 5 which is connected to the supply tank.

In dem Zylinder 1 ist zwischen zwei Treiberkolben 22 ein Steuerkolben 6 gelagert. Die Stirnflächen 7 der Treiberkolben 22 können über die Steuerräume 9 und 10 mit einem Steuerdruck in axialer Richtung beaufschlagt werden. An dem Steuerkolben sind jeweils über den beiden Druckauslaßkanälen 3 bzw. 4 ein Paar Kolbenringe 11 ausgebildet. Der Steuerkolben besitzt zwischen den Kolbenringen 11 ringförmige Ausnehmungen, damit die hydraulische Flüssigkeit den Kolben besser umfließen kann. In den gegenüber stehenden Abschnitten der Zylinderwand sind entsprechende (ringförmige) Kammern ausgebildet. Der Druck auf die Kolbenringe 11 wirkt daher auf den gesamten Umfang der Kolbenfläche. Die beiden Druckauslaßkanäle 3, 4 besitzen einen Durchmesser a, welcher der Dicke der ringförmigen Kammern entspreche. Die beiden Kolbenringe 11 besitzen einen Anstand in axialer Richtung voneinander derart, daß die Gesamtdicke D der beiden Kolbenringe größer ist als die Dicke der ringförmigen Kammern (a) bzw. der Durchmesser der Druckauslaßöffnungen 3 bzw. 4 an der Zylinderwandinnenseite. Die Hälfte der Differenz zwischen der Gesamtdicke D und der Dicke der ringförmigen Kammern bzw. dem Durchmesser der Druckauslaßkanäle (a) soll die positive Überdekkung x definieren. Die maximale Auslenkung des Steuerkolbens 6 aus der Ruhestellung soll mit y bezeichnet werden.In the cylinder 1, a control piston 6 is mounted between two driver pistons 22. The end faces 7 of the driver pistons 22 can be acted upon by a control pressure in the axial direction via the control chambers 9 and 10. A pair of piston rings 11 are formed on the control piston above the two pressure outlet channels 3 and 4, respectively. The control piston has annular recesses between the piston rings 11 so that the hydraulic fluid can flow around the piston better. Corresponding (annular) chambers are formed in the opposite sections of the cylinder wall. The pressure on the piston rings 11 therefore acts on the entire circumference of the piston surface. The two pressure outlet channels 3, 4 have a diameter a, which corresponds to the thickness of the annular chambers. The two piston rings 11 are spaced apart in the axial direction such that the total thickness D of the two piston rings is greater than the thickness of the annular chambers (a) or the diameter of the pressure outlet openings 3 and 4 on the inside of the cylinder wall. Half of the difference between the total thickness D and the thickness of the annular chambers or the diameter of the pressure outlet channels (a) should define the positive overlap x. The maximum deflection of the control piston 6 from the rest position is to be denoted by y.

Die druckfreien Außenräume des Zylinders 1 stehen über eine Ausgleichsleitung 12 und dem gemeinsamen Rückführkanal (5) miteinander in Verbindung.The pressure-free outer spaces of the cylinder 1 are connected to one another via a compensating line 12 and the common return duct (5).

Der Steuerkolben 6 ist in axialer Richtung über zwei Federn 8, die ebenfalls auf die Stirnflächen 7 der Treiberkolben 22 wirken, in der Nullstellung mittig zentriert im Ventilgehäuse gelagert. Mit dem Steuerkolben 6 ist in axialer Verlängerung ein elektrischer Lageaufnehmer 13 verbunden, der über einen aus dem Stand der Technik bekannten elektrischen Lageregelkreis 20 auf einen Torquemotor 14 rückgekoppelt ist. Lageregelkreis und Kompensationsschaltung 21 gemäß der Erfindung befinden sich in einem elektrisch isolierten Teil des Ventilgehäuses. Der Anker 15 des Torquemotors 14 wirkt direkt auf die Prallplatte 16 eines Düse 17-Prallplatte 16-Systems.The control piston 6 is axially centered in the valve housing by means of two springs 8, which also act on the end faces 7 of the driver piston 22. With the control piston 6, an electrical position sensor 13 is connected in an axial extension, which via an elek known from the prior art tric position control loop 20 is fed back to a torque motor 14. The position control loop and compensation circuit 21 according to the invention are located in an electrically insulated part of the valve housing. The armature 15 of the torque motor 14 acts directly on the baffle plate 16 of a nozzle 17 baffle plate 16 system.

Die Steuerräume 9 und 10 weisen einen Bypasskanal 18 und ein in diesem Kanal liegendes elektrisch zu betätigendes Ventil 19 auf, um bei geöffnetem Ventil miteinander verbunden zu werden.The control rooms 9 and 10 have a bypass channel 18 and an electrically operated valve 19 located in this channel in order to be connected to one another when the valve is open.

In Fig. 2 ist eine bevorzugte Ausführungsform der Kompensationsschaltung dargestellt. Die Schaltung besteht aus einem invertierenden Verstärker mit einem Eingangswiderstand R und einer Rückkopplungsschaltung, bestehend aus drei Rückkopplungszweigen, die auf den negativen Eingang des Operationsverstärkers rückwirken. Einer dieser Rückkopplungszweige besteht lediglich aus einem einstellbaren ohmschen Widerstand R3, die beiden anderen jeweils aus der Serienschaltung einer einstellbaren Spannungsquelle U1 bzw. U2, einer Diode D1 und D2 und einem einstellbaren Widerstand R1 bzw. R2. Die Dioden D1 bzw. D2 sind in bezug auf die Polaritäten der Spannungsquellen U1 bzw. U2 in Sperrichtung geschaltet.2 shows a preferred embodiment of the compensation circuit. The circuit consists of an inverting amplifier with an input resistor R and a feedback circuit consisting of three feedback branches which act on the negative input of the operational amplifier. One of these feedback branches only consists of an adjustable ohmic resistor R 3 , the other two each consist of a series connection of an adjustable voltage source U 1 or U 2 , a diode D 1 and D 2 and an adjustable resistor R 1 or R 2 . The diodes D 1 and D 2 are switched in the reverse direction with respect to the polarities of the voltage sources U 1 and U 2 .

Nimmt man ideale Bauteile an, so gelten folgende Zusammenhänge zwischen Ausgangs (UA)-und Eingangsspannung (UE):

  • UA = - UE . R3/R für U1 < UA < U2 UA = - UE . Ri/R für UA < U1 und R3 » R1 UA = - UE . R2/R für UA > U2 und R3 » R2
Assuming ideal components, the following relationships between output (U A ) and input voltage (U E ) apply:
  • U A = - U E. R 3 / R for U 1 <U A <U 2 U A = - UE. Ri / R for U A <U 1 and R 3 »R 1 U A = - U E. R 2 / R for U A > U 2 and R 3 »R 2

In Fig. 3 ist der Zusammenhang zwischen dem Eingangs- und dem Ausgangssignal graphisch dargestellt. Der Graph ist abschnittsweise durch die obenangegebenen Gleichungen definiert.In Fig. 3 the relationship between the input and the output signal is shown graphically. The graph is defined in sections by the equations given above.

Die Steigungen der geraden Abschnitte werden durch die Verhältnisse der Rückkopplungswiderstände Ri , R2, und R3 zum Eingangswiderstand R bestimmt. Je geringer das Verhältnis, desto flacher verläuft der jeweilige Geradenabschnitt.The slopes of the straight sections are determined by the ratios of the feedback resistors Ri, R 2 , and R 3 to the input resistance R. The lower the ratio, the flatter the respective straight line section.

Maßgebend für die Lage der Knickpunkte der Nichtlinearität sind die variablen Spannungsquellen U, und U2. Ein Erhöhen bzw. Erniedrigen der Spannung verschiebt den jeweiligen Knickpunkt in Richtung der positiven bzw. negativen Y-Achse des Diagramms in Fig. 3. Der Rückführkanal mit dem Widerstand R3, der immer wirksam ist, wird in Abhängigkeit vom Ausgangssignal in der oben angegebenen Weise parallel entweder zum Widerstand R1 oder R2 geschaltet.The variable voltage sources U and U 2 are decisive for the position of the break points of the non-linearity. Increasing or decreasing the voltage shifts the respective inflection point in the direction of the positive and negative Y-axis of the graph in Fig. 3. The return duct with the resistor R 3 that is always effective, is specified in dependence on the output signal in the above- Way connected in parallel to either resistor R 1 or R 2 .

Bereits ein sehr kleines positives Signal am Eingang der Kompensationsschaltung erzeugt an dessen Ausgang ein Signal der Amplitude U1. Dieses Signal verschiebt den Steuerkolben um die Auslenkung (x) aus seiner Runelage heraus. Dadurch beginnt sich der Druckauslaßkanal 4 bei einer weiteren Erhöhung des Eingangssignals sofort zu öffnen. Von diesem Knickpunkt an besteht ein linearer Zusammenhang zwischen dem elektrischen Stellsignal und dem Durchfluß durch das Ventil.Even a very small positive signal at the input of the compensation circuit generates a signal of amplitude U 1 at its output. This signal shifts the control piston out of its runelage by the deflection (x). As a result, the pressure outlet channel 4 begins to open immediately if the input signal is increased further. From this point onwards there is a linear relationship between the electrical control signal and the flow through the valve.

Der gleiche Vorgang geschieht in umgekehrter Weise für ein negatives Signal am Eingang der Kompensationsschaltung und dem Druckauslaßkanal 3. Dabei entsprechen sich die Knickpunkte der elektrischen Nichtlinearität (Fig. 3) und die der durch die positive Überdeckung entstandene nichtlineare Ventilkennlinie. Das bedeutet aber praktisch nichts anderes als ein lineares Verhalten des Ventils nach außen hin. Der Totbandbereich wird quasi "übersprungen", ohne den Durchfluß durch das Ventil abzusperren. Damit zeigt das Ventil nach außen hin über den gesamten Arbeitsbereich lineares Verhalten.The same process takes place in reverse for a negative signal at the input of the compensation circuit and the pressure outlet channel 3. The breakpoints correspond to the electrical non-linearity (FIG. 3) and that of the non-linear valve characteristic curve resulting from the positive overlap. However, this means practically nothing other than a linear behavior of the valve towards the outside. The dead band area is practically "skipped" without blocking the flow through the valve. The valve thus shows linear behavior towards the outside over the entire working range.

Öffnet sich bei einer Unterbrechung der Stromzufuhr das im Bypasskanal 18 liegende Ventil 19, werden die Steuerkammern 9, 10 hydraulisch kurzgeschlossen. Dadurch gleicht sich ein bestehender Druckunterschied in den Steuerkammern sofort aus und die Rückstellfedern 8 verschieben den Steuerkolben 6 in den Bereich positiver Überdeckung. Hier ist der absolute sichere Stillstand des Verbrauchers gewährleistet, da keine Leckströme im Überdeckungsbereich auftreten können. Damit wird dem Sicherheitsbedürfnis Rechnung getragen.If the valve 19 located in the bypass channel 18 opens when the power supply is interrupted, the control chambers 9, 10 are hydraulically short-circuited. As a result, an existing pressure difference in the control chambers is immediately equalized and the return springs 8 move the control piston 6 into the area of positive overlap. Here the absolute safe standstill of the consumer is guaranteed, since no leakage currents can occur in the overlap area. This takes into account the need for security.

Claims (4)

1. Elektrohydraulisches Servoventil, mit einem proportionalen Zusammenhang zwischen dem elektrischen Stellsignal und der Auslenkung des Steuerkolbens (6) des Servoventils, wobei das Servoventil einen Zylinder (1) und einen darin gelagerten Steuerkolben (6) aufweist, und der Steuerkolben auf seinen beiden Stirnseiten (7) in druckbeaufschlagbaren Steuerkammern (9, 10) liegt, um den Kolben (6) bei einem Druckunterschied in diesen beiden Steuerkammern (9, 10) aus seiner neutralen Stellung auszulenken, wobei der Zylinder einen mittigen Druckeinlaßkanal (2) und zwei in axialer Richtung versetzt angeordnete Druckauslaßkanäle (3, 4) aufweist, die durch den Steuerkolben (6) verschlossen sind, wenn er sich in seiner neutralen Lage befindet und bei ausgelenktem Steuerkolben (6) teilweise bis ganz geöffnet werden, um einen von der Lage des Steuerkolbens abhängigen Durchlaßquerschnitt zwischen einem der Druckauslaßkanäle (3, 4) und dem Druckeinlaßkanal (2) freizugeben, wobei der Druckunterschied in den Steuerkammern (9, 10) durch das elektrische Stellsignal erzeugt wird, dadurch gekennzeichnet, daß der Steuerkolben (6) derart dimensioniert ist, daß er den einen oder den anderen Druckauslaßkanal (3, 4) erst bei einer vorgegebenen axialen Auslenkung (x) aus seiner neutralen Stellung zu öffnen beginnt (positive Überdekkung), und daß zum Ausgleich der durch die positive Überdeckung entstandenen Nichtlinearität zwischen dem elektrischen Steuersignal und der Auslenkung des Steuerkolbens (6) eine elektrische Kompensationsschaltung (21) vorgesehen ist und daß die beiden Steuerräume (9, 10) über einen Bypasskanal (18) miteinander zum Druckausgleich über ein in dem Kanal liegendes elektrisch zu betätigendes Ventil (19) verbindbar sind, und daß das Ventil (19) derart ausgebildet ist, daß es im stromlosen Zustand öffnet.1. Electro-hydraulic servo valve, with a proportional relationship between the electrical control signal and the deflection of the control piston (6) of the servo valve, the servo valve having a cylinder (1) and a control piston (6) mounted therein, and the control piston on its two end faces ( 7) in pressurizable control chambers (9, 10) to deflect the piston (6) at a pressure difference in these two control chambers (9, 10) from its neutral position, the cylinder having a central pressure inlet channel (2) and two in the axial direction has staggered pressure outlet channels (3, 4) which are closed by the control piston (6) when it is in its neutral position and partially or fully opened when the control piston (6) is deflected, by a passage cross-section dependent on the position of the control piston to release between one of the pressure outlet channels (3, 4) and the pressure inlet channel (2), the pressure being below departed in the tax chambers (9, 10) is generated by the electrical control signal, characterized in that the control piston (6) is dimensioned such that it only presses one or the other pressure outlet channel (3, 4) at a predetermined axial deflection (x) from its neutral Position begins to open (positive overlap), and that an electrical compensation circuit (21) is provided to compensate for the non-linearity between the electrical control signal and the deflection of the control piston (6), and that the two control spaces (9, 10) can be connected to one another via a bypass duct (18) for pressure equalization via an electrically operated valve (19) located in the duct, and that the valve (19) is designed such that it opens when de-energized. 2. Servoventil nach Anspruch 1, dadurch gekennzeichnet, daß die vorgegebene axiale Auslenkung (x) vorzugsweise 10% des maximalen Stellweges (y) beträgt.2. Servo valve according to claim 1, characterized in that the predetermined axial deflection (x) is preferably 10% of the maximum travel (y). 3. Servoventil nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die elektrische Kompensationsschaltung (21) in das Ventilgehäuse integriert ist.3. Servo valve according to claim 1 or 2, characterized in that the electrical compensation circuit (21) is integrated in the valve housing. 4. Servoventil nach wenigstens einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die elektrische Kompensationsschaltung (21) wenigstens einen Operationsverstärker aufweist, daß der Operationsverstärker mit einer Rückkoppelschaltung versehen ist, die ihm eine Nichtlinearität verleiht, die die durch die positive Überdeckung entstandende Nichtlinearität ausgleicht.4. Servo valve according to at least one of claims 1 to 3, characterized in that the electrical compensation circuit (21) has at least one operational amplifier, that the operational amplifier is provided with a feedback circuit which gives it a non-linearity which the non-linearity created by the positive overlap compensates.
EP19900116279 1990-08-24 1990-08-24 Electrohydraulic servovalve Expired - Lifetime EP0471884B1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP19900116279 EP0471884B1 (en) 1990-08-24 1990-08-24 Electrohydraulic servovalve
DE59010152T DE59010152D1 (en) 1990-08-24 1990-08-24 Electro-hydraulic servo valve
JP20564991A JPH0626501A (en) 1990-08-24 1991-07-23 Electronic hydraulic servo valve
US07/749,216 US5165448A (en) 1990-08-24 1991-08-23 Two-stage servovalve with compensatoin circuit to accommodate "dead zone" du

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19900116279 EP0471884B1 (en) 1990-08-24 1990-08-24 Electrohydraulic servovalve

Publications (2)

Publication Number Publication Date
EP0471884A1 true EP0471884A1 (en) 1992-02-26
EP0471884B1 EP0471884B1 (en) 1996-02-21

Family

ID=8204370

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900116279 Expired - Lifetime EP0471884B1 (en) 1990-08-24 1990-08-24 Electrohydraulic servovalve

Country Status (4)

Country Link
US (1) US5165448A (en)
EP (1) EP0471884B1 (en)
JP (1) JPH0626501A (en)
DE (1) DE59010152D1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2694617A1 (en) * 1992-08-06 1994-02-11 Hr Textron Inc Electro-hydraulic servo valve with gain compensation.
DE4227563A1 (en) * 1992-08-20 1994-02-24 Rexroth Mannesmann Gmbh Electrohydraulic position regulator with two-stage proportional valve - has pilot electrohydraulic stage used to drive main fluid power stage with both having displacement sensors

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5884894A (en) * 1996-08-20 1999-03-23 Valtek, Inc. Inner-loop valve spool positioning control apparatus
US6318182B1 (en) * 1999-06-04 2001-11-20 Eaton Corporation Measurement of transmission oil pressure by monitoring solenoid current
CN1295441C (en) * 2004-11-05 2007-01-17 宁波华液机器制造有限公司 Proportional differential pressure control valve
RU2346187C2 (en) * 2007-03-30 2009-02-10 Валерий Иванович Разинцев Three-stage electrohydraulic power amplifier
RU2489607C1 (en) * 2011-12-09 2013-08-10 Валерий Иванович Разинцев Two-stage electrohydraulic amplifier with electric flow feedback
RU2467215C1 (en) * 2011-09-27 2012-11-20 Валерий Иванович Разинцев Three-stage electrohydraulic amplifier with electric flow feedback
WO2013048283A1 (en) * 2011-09-27 2013-04-04 Razintsev Valery Ivanovich Electrohydraulic amplifier with electrical feedback on consumption
RU2482341C1 (en) * 2011-12-01 2013-05-20 Валентин Григорьевич Жарков Servo valve with jet control
RU2488719C1 (en) * 2011-12-09 2013-07-27 Валерий Иванович Разинцев One-stage hydraulic booster with flow rate electric feedback
DE102014205041A1 (en) * 2014-03-19 2015-09-24 Robert Bosch Gmbh Pressure reducing valve
JP6775288B2 (en) * 2015-10-08 2020-10-28 株式会社堀場エステック Fluid control valve and its control program
US10753376B2 (en) * 2016-01-29 2020-08-25 Komatsu Ltd. Hydraulic cylinder spool valve device
US10927866B2 (en) 2017-12-15 2021-02-23 Eaton Intelligent Power Limited Leakage modulation in hydraulic systems containing a three-way spool valve
JP7008499B2 (en) * 2017-12-27 2022-01-25 株式会社堀場エステック Calibration data creation device, calibration data creation method, and flow control device
GB2581160B (en) * 2019-02-05 2022-10-19 Domin Fluid Power Ltd Rotary servo valve
EP3921550B1 (en) 2019-02-05 2025-06-18 Domin Limited Rotary servo valve
CN110109348B (en) * 2019-05-13 2023-03-10 河南工学院 Depth-based hydraulic proportional valve bidirectional dead zone compensation method
US11473598B2 (en) 2019-10-25 2022-10-18 Woodward, Inc. Failsafe electro-hydraulic servo valve
US11852250B2 (en) 2022-04-11 2023-12-26 Fisher Controls International Llc Adjustable spool valve for a digital valve controller
CN119934105A (en) * 2025-04-03 2025-05-06 苏州海卓伺服驱动技术有限公司 Electro-hydraulic servo valve with rotary direct drive valve as pilot and control method thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2439920A1 (en) * 1978-10-17 1980-05-23 Bosch Gmbh Robert Electrohydraulic valve with pre- and main control stages - uses only one proportional magnet and only one spring to load pre-control slide
EP0376023A2 (en) * 1988-12-30 1990-07-04 Robert Bosch Gmbh Electrohydraulic proportional valve

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4192551A (en) * 1978-10-10 1980-03-11 Bethlehem Steel Corporation Remote control system for mining machines
US4466337A (en) * 1982-01-25 1984-08-21 Sundstrand Corporation Electro hydraulic control with dead zone compensation
US4766921A (en) * 1986-10-17 1988-08-30 Moog Inc. Method of operating a PWM solenoid valve

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2439920A1 (en) * 1978-10-17 1980-05-23 Bosch Gmbh Robert Electrohydraulic valve with pre- and main control stages - uses only one proportional magnet and only one spring to load pre-control slide
EP0376023A2 (en) * 1988-12-30 1990-07-04 Robert Bosch Gmbh Electrohydraulic proportional valve

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
OLHYDRAULIK UND PNEUMATIK. vol. 33, no. 10, Oktober 1989, MAINZ DE Seiten 786 - 789; berthold klug: "neue stetigventile zum steuern und regeln von plastverarbeitungsmachinen" *
ZEITSCHRIFT DES VEREINES DEUTSCHER INGENIEURE. vol. 128, no. 7, April 1986, DUSSELDORF DE Seiten 235 - 238; von gerd scheffel: "stetige richtungssteuerung" *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2694617A1 (en) * 1992-08-06 1994-02-11 Hr Textron Inc Electro-hydraulic servo valve with gain compensation.
DE4227563A1 (en) * 1992-08-20 1994-02-24 Rexroth Mannesmann Gmbh Electrohydraulic position regulator with two-stage proportional valve - has pilot electrohydraulic stage used to drive main fluid power stage with both having displacement sensors
DE4227563C2 (en) * 1992-08-20 2000-04-13 Mannesmann Rexroth Ag Controlled hydraulic feed drive

Also Published As

Publication number Publication date
JPH0626501A (en) 1994-02-01
EP0471884B1 (en) 1996-02-21
DE59010152D1 (en) 1996-03-28
US5165448A (en) 1992-11-24

Similar Documents

Publication Publication Date Title
EP0471884A1 (en) Electrohydraulic servovalve
DE3688598T2 (en) Devices for damping piston movements.
DE2446963C2 (en) Hydraulic control device
DE3114437C2 (en) Pressure control valve
DE3130056A1 (en) CONTROL VALVE ARRANGEMENT FOR A PRESSURE WORKING CYLINDER
EP0620371B1 (en) Hydraulic system for supply of open or closed hydraulic functions
EP0864794A2 (en) Proportional throttle valve
EP0681128A1 (en) Solenoid valve
DE2305798B2 (en) Hydraulic control device for a servomotor, in particular for vehicle steering
DE2921030A1 (en) CONTROL VALVE ARRANGEMENT
DE102007054137A1 (en) Hydraulic valve device
EP0342410A2 (en) Safety valve
DE3205860C2 (en)
DE2303286A1 (en) HYDRAULIC CONTROL DEVICE
EP0238782B1 (en) 5/3-way valve unit
DE2349620C2 (en) Remote control system for a hydraulic power transmission device
DE2602381A1 (en) TWO-STAGE FLOW RATE CONTROL VALVE ARRANGEMENT
EP0041247A2 (en) Pilot-operated device for load-independent flow control
EP1342597B2 (en) Assembly for active roll stabilisation of a motor vehicle
DE4417153C1 (en) Position regulation circuit for hydraulic setting element in automobile
EP0044518A1 (en) Displacement control system for a variable displacement pump
DE4418514B4 (en) Electrohydraulic directional valve
EP0376023B1 (en) Electrohydraulic proportional valve
WO2004020840A1 (en) Hydraulic drive for a control valve
DE3106532C2 (en)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LI LU NL SE

RBV Designated contracting states (corrected)

Designated state(s): DE GB IT

17P Request for examination filed

Effective date: 19920824

17Q First examination report despatched

Effective date: 19940301

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE GB IT

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19960221

REF Corresponds to:

Ref document number: 59010152

Country of ref document: DE

Date of ref document: 19960328

ITF It: translation for a ep patent filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20030730

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040824

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20040824

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050824

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20051020

Year of fee payment: 16

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20070301