(19)
(11)EP 3 431 780 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
15.04.2020 Bulletin 2020/16

(21)Application number: 17461572.4

(22)Date of filing:  20.07.2017
(51)International Patent Classification (IPC): 
F15B 13/043(2006.01)
F16K 11/07(2006.01)

(54)

SERVOVALVE

SERVOVENTIL

SERVO-SOUPAPE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
23.01.2019 Bulletin 2019/04

(73)Proprietor: Hamilton Sundstrand Corporation
Charlotte, NC 28277 (US)

(72)Inventors:
  • CIS, Marcin
    Lutynia (PL)
  • ZURAW, Sebastian
    45-368 Opole (PL)

(74)Representative: Dehns 
St. Bride's House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
US-A- 2 977 985
US-A- 3 698 437
US-A- 3 081 787
US-A- 4 922 964
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] The present disclosure relates to servovalves used to transfer quantities of, or manage the flow of fluid e.g. air.

    BACKGROUND



    [0002] Servovalves find a wide range of applications for controlling air or other fluid flow to effect driving or control of another part e.g. an actuator.

    [0003] A servovalve assembly includes a motor controlled by a control current which controls flow to a valve e.g. an air valve to control an actuator. Generally, a servovalve transforms an input control signal into movement of an actuator cylinder. The actuator controls e.g. an air valve. In other words, a servovalve acts as a controller, which commands the actuator, which changes the position of an air valve's (e.g. a so-called butterfly valve's) flow modulating feature.

    [0004] Such mechanisms are used, for example, in various parts of aircraft where the management of air/fluid flow is required, such as in engine bleeding systems, anti-ice systems, air conditioning systems and cabin pressure systems. Servovalves are widely used to control the flow and pressure of pneumatic and hydraulic fluids to an actuator, and in applications where accurate position or flow rate control is required.

    [0005] Conventionally, servovalve systems operate by obtaining pressurised fluid from a high pressure source which is transmitted through a load from which the fluid is output as a control fluid. Various types of servovalves are known - see e.g. GB 2104249, US 2015/0047729, US-3,081,787-A, US-3,698,437-A, US-4,922,964-A, US-2,977,985-A and US 9,309,900.

    [0006] Electrohydraulic servovalves can have a first stage with a motor, e.g. an electrical or electromagnetic force motor or torque motor, controlling flow of a hydraulic fluid to drive a valve member e.g. a spool valve of a second stage, which, in turn, can control flow of hydraulic fluid to an actuator for driving a load. The motor can operate to position a moveable member, such as a flapper, in response to an input drive signal or control current, to drive the second stage valve member e.g. a spool valve.

    [0007] Particularly in aircraft applications, but also in other applications, servovalves are often required to operate at various pressures and temperatures. For e.g. fast acting air valve actuators, relatively large flows are required depending on the size of the actuator and the valve slew rate. For such high flow rates, however, large valve orifice areas are required. For 'flapper' type servovalves, problems arise when dealing with large flows due to the fact that flow force acts in the direction of the flapper movement and the motor is forced to overcome the flow forces. For clevis-like metering valves such as described in US 4,046,061 and US 6,786,238, the flow forces, proportional to the flow, act simultaneously in opposite directions so that the clevis is balanced and centred. The clevis, however, needs to be big due to the requirement for bigger orifices to handle larger flows.

    [0008] Jet pipe servovalves provide an alternative to 'flapper'- type servovalves. Jet pipe servovalves are usually larger than flapper type servovalves but are less sensitive to contamination. In jet pipe systems, fluid is provided via a jet pipe to a nozzle which directs a stream of fluid at a receiver. When the nozzle is centred - i.e. no current from the motor causes it to turn, the receiver is hit by the stream of fluid from the nozzle at the centre so that the fluid is directed to both ends of the spool equally. If the motor causes the nozzle to turn, the stream of fluid from the nozzle impinges more on one side of the receiver and thus on one side of the spool more than the other causing the spool to shift. The spool shifts until the spring force of a feedback spring produces a torque equal to the motor torque. At this point, the nozzle is centred again, pressure is equal on both sides of the receiver and the spool is held in the centred position. A change in motor current moves the spool to a new position corresponding to the applied current.

    [0009] As mentioned above, jet pipe servovalves are advantageous in that they are less sensitive to contamination e.g. in the supply fluid or from the valve environment. These valves are, however, more complex and bulkier. Additional joints are required for the fluid supply pipe and the supply pipe from the fluid supply to the jet pipe is mounted outside of the servovalve body in the torque motor chamber. In the event of damage to the pipe, this can result in external leakage. The pipe, being external, adds to the overall size and is more vulnerable to damage.

    [0010] There is a need for a servovalve arrangement that can handle large fluid flows effectively, whilst retaining a compact design and being less vulnerable to contamination, damage and leakage.

    [0011] European Patent Application 16461572 teaches a jet-pipe type servovalve wherein fluid is provided to the nozzle via a connector header in fluid communication with the interior of the spool, the spool being provided with one or more openings via which fluid from the supply port enters the interior of the spool and flows into the connector header and to the nozzle.

    [0012] The servovalve includes drive means for steering the nozzle in response to the control signal. The drive means may include a motor such as a torque motor arranged to steer the nozzle by means of an induced current. Other drive means may be used to vary the position of the nozzle. The drive means may be mounted in a housing attached to the valve assembly.

    [0013] The arrangement of EP 16461572 enables the conventional outside supply pipe to be removed and allows the jet pipe to be fed with fluid via the spool and a feedback spring. To avoid clogging of the jet pipe/nozzle etc. due to contamination in the fluid, the fluid should be filtered. Conventionally, the fluid will be filtered by an external filter before it enters the jet pipe. This, however, requires filter components to be incorporated in e.g. the connector header, which is difficult to do.

    [0014] There is, therefore, a need to provide a simpler, more convenient and reliable fluid filtering in such a jet-pipe servovalve.

    [0015] In one aspect, the present disclosure provides a spool for a servovalve, the spool comprising a tubular body defining a path for fluid flow, the tubular body closed at each end by a respective end cap; the spool further being provided with openings in the tubular body via which, in use, fluid enters the interior of the spool; and characterised in that the end caps extend within the tubular body at least to an extent that they overlap the openings, and wherein the end caps are provided with filter means for filtering the fluid from the openings as it enters the interior of the spool.

    [0016] The present disclosure also provides a servovalve comprising: a fluid transfer valve assembly comprising a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a jet pipe assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow; wherein the jet pipe assembly comprises a steerable nozzle from which fluid is directed to the ends of the spool in an amount determined by the control signal; and wherein fluid is provided to the nozzle via a connector header in fluid communication with the interior of the spool, the spool comprising a tubular body defining a path for fluid flow, the tubular body closed at each end by a respective end cap; the spool further being provided with openings in the tubular body via which, in use, fluid enters the interior of the spool; and characterised in that the end caps extend within the tubular body at least to an extent that they overlap the openings, and wherein the end caps are provided with filter means for filtering the fluid from the openings as it enters the interior of the spool.

    [0017] The end cap may comprise a head part and a shaft, which is preferably a thin walled shaft, such that the head fits sealing at the end of the spool and the shaft extends along the inside

    [0018] Preferred embodiments will now be described with reference to the drawings.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0019] 

    Fig. 1 is a schematic view of a conventional jet-pipe type servovalve.

    Fig. 2 is a cut-away view of a servovalve according to e.g. EP16461572.

    Fig. 2A is a detail of the servovalve of Fig. 2.

    Fig. 3 is a partial sectional view of a servovalve according to the disclosure.

    Fig. 4 is a detailed view of an end of the servovalve of Fig. 3.

    Fig. 5 is a cut-away view of the servovalve of Fig. 3


    DETAILED DESCRIPTION



    [0020] A servovalve as described below can, for example, be used in an actuator control system. The servovalve is controlled by a torque motor to control a control flow of fluid that is output via e.g. a butterfly value to control the movement of an actuator.

    [0021] A conventional jet pipe servovalve will first be described with reference to Fig. 1. The arrangement comprises a servovalve assembly have a torque motor and a moveable spool 4 mounted in a supporting block 5, or mounted in a cylinder mounted in a block. The spool is part of a spool assembly having: supply ports 14, control ports 15, and a return port 16. Flow is possible between the ports via a passage through the spool. The torque motor provides current that causes a jet pipe 18 to turn at its end closest to the spool, which end terminates in a nozzle 19. Supply fluid is provided from the supply port, via a supply pipe 25 to the top of the jet pipe - i.e. the end opposite the end with the nozzle, and the supply fluid flows through the jet pipe and out of the nozzle. A receiver 21 is provided in the block below the nozzle. The receiver provides two channels via which fluid from the nozzle 19 flows into the spool. When no current is applied by the motor to the jet pipe, the nozzle is centred relative to the receiver 21 and supply fluid exiting the nozzle flows equally through both channels and thus equally to both ends of the spool. The spool therefore remains centred - i.e. 'closed' so that no fluid flows through the control ports. When actuator control is desired, the motor provides a control current to the jet pipe causing the nozzle to turn away from the centred position. The supply fluid through the nozzle then flows predominantly through one receiver channel as compared to the other channel. More fluid flows, therefore, into the corresponding end of the spool causing axial movement of the spool with either blocks/occludes the passage between the supply port and the respective control port or opens the passage to allow flow between the two ports, depending on the axial position of the spool due to the position of the nozzle, thus modulating pressure on the control ports and controlling the actuator.

    [0022] In an example, the assembly is arranged to control an actuator based on the fluid flow from the control port e.g. via a butterfly valve. The servovalve controls an actuator which, in turn, controls an air valve such as a butterfly valve.

    [0023] Supply pressure is provided to the servovalve housing via supply port 24 and to the spool via spool supply ports 14. The pressure at return port 16 is a return pressure which will vary depending e.g. on the altitude of the aircraft in flight. Control ports 15 provide a controlled pressure, dependant on the nozzle position and resulting spool position, to be provided to an actuator. A supply pipe 25 is also connected to the supply port and routes supply fluid external to the spool and into the top end of the jet pipe. The supply fluid flows down the jet pipe to the nozzle and exits to the receiver described above. The jet pipe is preferably mounted in a flexural tube 26. While the nozzle is centred, equal amounts of fluid go to the two ends 4a,4b of the spool.

    [0024] The spool 4 is in the form of a tubular member arranged in the block 5 to be moved axially by fluid from the jet pipe via the nozzle that is directed at the spool via the receiver. End caps seal the ends of the tubular member.

    [0025] A feedback spring 27 serves to return the nozzle to the centred position.

    [0026] In more detail, to open the servovalve, control current is provided to coils of the motor (e.g. a torque motor) creating electromagnetic torque opposing the sum of mechanical and magnetic torque already 'present' in the torque motor. The bigger the electromagnetic force from the coils, the more the jet pipe nozzle 19 turns. The more it turns, the greater the linear or axial movement of the spool 4. A torque motor usually consists of coil windings, a ferromagnetic armature, permanent magnets and a mechanical spring (e.g. two torsional bridge shafts). This arrangement provides movement of the nozzle proportional to the input control current. Other types of motor could be envisaged.

    [0027] The servovalve assembly of EP 16461572, described with reference to Figs. 2 and 2A, avoids the need for the supply pipe 25, thus avoiding many of the disadvantages of conventional jet pipe servovalves. Instead of providing supply fluid to the jet pipe externally, in the present disclosure the supply fluid is provided to the jet pipe from inside the servovalve assembly, using the flow of supply fluid provided to the spool supply ports. To do this, openings 28 are provided in the wall of the spool 4 to enable the supply fluid provided to the spool 4 via the supply port to flow inside the spool body as shown by arrows a1, a2 of Fig. 2. The jet pipe 18' extends into the interior of the spool 4 and is preferably secured in position e.g. by clamps or screws 29. The supply fluid, which is conventionally supplied at a pressure of around 10 mPa, but may of course be other pressure values including much higher pressures e.g. 21 MPa, flows into the interior of the spool 4 towards the middle (arrows b1,b2) and is drawn up, under pressure, into the end of the jet pipe 18' extending into the spool (arrow c). This end is in fluid engagement with the nozzle 19' as can best be seen in Fig. 2. Arrows d1 and d2 show how the fluid flows from the jet pipe 18' into the nozzle 19' from which it exits as in conventional systems to the receiver 21.

    [0028] Figure 2 shows, again by arrows, how the fluid flows from the supply port into the opening(s) 28 into spool 4 and then to the end of the jet pipe 18' extending into the spool. The spool body is sealed at each end by a respective end cap 100.

    [0029] With this arrangement, the jet pipe 18' can be in the form of a pipe extending into the spool with a connector header piece 30 defining a flow channel from the jet pipe to the nozzle 19'. The header piece 30 can be formed integrally with the pipe or could be formed as a separate piece and attached to the pipe by e.g. brazing or welding. As only the header piece needs to be under pressure, making it as a separate component can be advantageous in terms of manufacturing.

    [0030] Something is required to steer the nozzle 19' in response to motor current to control the valve by moving the spool. In conventional systems, this is provided by the body of the jet pipe extending out of the spool, preferably within a flexural tube. In the system of EP16461572 and of this disclosure, it is not necessary to have the externally extending jet pipe and so this could be replaced by e.g. a simple wire (not shown) which may be mounted in a flexural tube 26' and which is moved by the motor current to turn the nozzle to provide the desired flow to respective ends of the spool via the receiver.

    [0031] The jet pipe, supplied by the spool thus also functions as the feedback spring needed in the conventional system.

    [0032] Such a system has fewer component parts than conventional systems; there is less risk of leakage into the motor chamber as the supply pressure remains within the assembly; fewer connections and joints are required and the assembly can be smaller.

    [0033] According to the present disclosure, the assembly described above is improved by providing means for filtering the fluid as it flows into the interior of the spool body via the openings. The filter means is therefore provided on or in the end caps 200 which are arranged to extend within the spool body at least as far as the opening(s) 28 where the fluid enters the interior to be supplied to the jet pipe. One embodiment, is shown in Fig. 3. The end caps 200, at least where they overlap the openings 28, are made to provide a filtration surface between the openings 28 and the interior of the spool 4 across which the fluid must pass before it enters the interior of the spool. In one example, the filtration surface is provided by perforations formed in a thin wall of the end caps 200 by e.g. laser or in any other known manner.

    [0034] Fig. 4 shows the filtration surface in more detail.

    [0035] Fig. 5 shows a cross-section of the spool with the filtering end caps 200. Referring to Figs. 3, 4 and 5, the arrangement of the disclosure will be described by way of example. Where components correspond to conventional systems, the same references are used.

    [0036] As in conventional servovalves, the spool 4 is a tubular or cylindrical body defined by a wall, which defines a passage for the fluid flow. The openings 28 are formed in the spool wall with, preferably, one opening close to each end 4a,4b of the spool body such that the fluid is controlled to act against the respective spool ends 4a, 4b to appropriately move the spool as described above. This controls the flow of fluid from the control port.

    [0037] Screws 300 are provided towards the centre of the spool body to hold the end of the jet pipe in place. The screws can be adjusted if necessary in view of system tolerances.

    [0038] In conventional systems, the end caps 100 are provided as plugs or seals, made of e.g. steel, sealingly secured in the ends of the spool body to prevent leakage of fluid from those ends and to maintain the desired pressure differential across the spool.

    [0039] In the arrangement of this disclosure, the end caps 200 are formed with a head 600 such as the conventional end caps 100 and a longer shaft 500 that extends further into the body of the spool when the caps are in place to plug the ends. The extended shaft 500 is a thin-walled (in one realisation approx.. 0.2mm) tubular shaft, also made of e.g. steel. The thin-walled shaft extends inside the tubular body past the openings 28 in the spool body wall providing a surface between the opening and the interior of the spool. The thin-walled shaft, at least at the position where the shaft overlaps the opening (but also possibly along more or all of the shaft) provides a filtration surface 400 to filter out particulate matter from the fluid as it passes from the opening into the interior of the spool 4. Most preferably, the filtration surface 400 is provided by perforations 700 formed in the thin wall of the end cap shaft 500, the perforations sized to prevent passage of debris/particulate matter, but to allow passage of the control fluid. One way of forming such perforations is by laser cutting but other methods are also possible.

    [0040] It is important, for optimal filtering, to ensure that the radial clearance 800 between the spool body and the end cap 200 is very small - ideally smaller than the diameter of the perforations - to prevent fluid entering the opening and passing along a clearance gap between the spool and the end cap shaft and into the interior of the spool 4.

    [0041] The end caps 200 must be sized to fit inside the spool body with a very small clearance therebetween - most preferably a clearance smaller than the size of the filter perforations, to prevent debris, particulate matter etc. escaping between the inner wall of the spool and the outer wall of the end caps rather than passing through the filter.

    [0042] As compared to conventional servovalve arrangements with an additional filter component, the number of parts in the system of this disclosure is reduced, thus reducing cost, manufacturing time and complexity and scope for parts failure. A relatively large filtration area is possible providing more reliable and effective filtration. Further, no additional space is required in the valve assembly for a filter and so the overall size and weight of the assembly is minimised. The end caps are already part of the system. The filtration end caps are also easily accessible from outside the spool, easy to remove, clean and replace and so, in case of blockage or damage, it is not necessary to replace the whole assembly. It is also not necessary to undo the accurately adjusted screws 300 when removing the filter.

    [0043] Although this disclosure has been described in terms of preferred examples, it should be understood that these examples are illustrative only and modifications and alterations are possible within the scope of the claims.


    Claims

    1. A servovalve comprising: a fluid transfer valve assembly comprising a supply port and a control port; a moveable valve spool (4) arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a jet pipe assembly configured to axially move the valve spool (4) relative to the fluid transfer valve assembly in response to the control signal to regulate the fluid flow; wherein the jet pipe assembly comprises a steerable nozzle (19') from which fluid is directed to the ends (4a, 4b) of the spool (4) in an amount determined by the control signal; and wherein fluid is provided to the nozzle (19') via a connector header (30) in fluid communication with the interior of the spool (4), the spool (4) comprising a tubular body defining a path for fluid flow, the tubular body closed at each end by a respective end cap (200); the spool (4) further being provided with openings (28) in the tubular body via which, in use, fluid enters the interior of the spool (4); and characterised in that the end caps (200) extend within the tubular body at least to an extent that they overlap the openings (28), and wherein the end caps (200) are provided with filter means (201) for filtering the fluid from the openings (28) as it enters the interior of the spool (4).
     
    2. The servovalve of claim 1, wherein the filter means (201) comprises perforations (700) formed in the end cap (200) where they overlap the openings.
     
    3. The servovalve of claim 1 or 2, wherein the end caps (200) comprise a head part (600) configured to sealingly sit in the end of the spool and a shaft (500) extending from the head along the interior of the spool.
     
    4. The servovalve of and preceding claim, wherein the end caps (200) comprise a thin wall where they overlap the openings.
     
    5. The servovalve of any preceding claim, wherein the openings (28) comprise an opening provided towards each end of the spool.
     
    6. The servovalve of any preceding claim, further comprising drive means for steering the nozzle (19') in response to the control signal.
     
    7. The servovalve of any preceding claim, wherein the nozzle (19') is provided at an end of a jet pipe (18') closest to the valve assembly and fluid from the nozzle (19') is directed into the valve assembly via a receiver.
     
    8. The servovalve of Claim 7, wherein the receiver is configured such that when the nozzle (19') is in a central position, fluid enters the fluid transfer valve assembly evenly via both sides of the receiver when the nozzle (19') is steered to an off-centre position, more fluid flows to one side of the fluid transfer valve assembly than the other via the receiver.
     
    9. The servovalve of Claim 7, wherein the receiver comprises lateral receiver channels to provide flow to each side of the fluid transfer valve assembly.
     
    10. The servovalve of any preceding claim, wherein the connector header (30) is formed integrally with the nozzle (19') or wherein the connector header (30) is formed as a separated component and attached to the nozzle (19').
     
    11. The servovalve of any preceding claim, wherein the connector header (30) comprises an inlet to receive supply fluid and an outlet in fluid communication with the nozzle (19').
     
    12. The servovalve of any preceding claim, wherein the nozzle (19') is provided on a jet pipe (18') mounted within a flexible tube (26'), wherein the flexible tube (26') imparts movement to the jet pipe (18') to steer the nozzle (19') in response to the control signal.
     
    13. The servovalve of Claim 12, wherein the jet pipe (18') comprises a nozzle portion and a main body portion (20').
     
    14. The servovalve of Claim 13, wherein the main body portion (20') is in the form of a tube or wherein the main body portion (20') is in the form of a rod or wire.
     


    Ansprüche

    1. Servoventil, das Folgendes umfasst: eine Fluidübertragungsventilvorrichtung, die eine Zuführöffnung und eine Steueröffnung umfasst; einen beweglichen Ventilschieber (4), der dazu angeordnet ist, den Fluidstrom von der Zuführöffnung zu der Steueröffnung als Reaktion auf ein Steuersignal zu regulieren; und eine Strahlrohrvorrichtung, die dazu konfiguriert ist, den Ventilschieber (4) als Reaktion auf das Steuersignal zum Regulieren des Fluidstroms axial im Verhältnis zu der Fluidübertragungsventilvorrichtung zu bewegen; wobei die Strahlrohrvorrichtung eine lenkbare Düse (19') umfasst, von der Fluid in einer durch das Steuersignal bestimmten Menge an die Enden (4a, 4b) des Schiebers (4) geleitet wird; und wobei Fluid über einen Verbinder (30), der in Fluidkommunikation mit dem Innenraum des Schiebers (4) steht, an die Düse (19') bereitgestellt wird, wobei der Schieber (4) einen röhrenförmigen Körper umfasst, der einen Weg für den Fluidstrom definiert, wobei der röhrenförmige Körper an jedem Ende durch eine entsprechende Endkappe (200) verschlossen ist; wobei der Schieber (4) ferner mit Öffnungen (28) in dem röhrenförmigen Körper bereitgestellt ist, über welche bei Nutzung Fluid in den Innenraum des Schiebers (4) eintritt; und dadurch gekennzeichnet, dass sich die Endkappen (200) innerhalb des röhrenförmigen Körpers zumindest in einem solchen Umfang erstrecken, dass sie die Öffnungen (28) überlappen, und wobei die Endkappen (200) mit einem Filtermittel (201) bereitgestellt sind, das das Fluid von den Öffnungen (28) filtert, wenn es in den Innenraum des Schiebers (4) eintritt.
     
    2. Servoventil nach Anspruch 1, wobei das Filtermittel (201) Perforationen (700) umfasst, die in der Endkappe (200) gebildet sind, wo sie die Öffnungen überlappen.
     
    3. Servoventil nach Anspruch 1 oder 2, wobei die Endkappen (200) einen Kopfteil (600), der dazu konfiguriert ist, dichtend in dem Ende des Schiebers zu sitzen, und eine Welle (500) umfassen, die sich von dem Kopf entlang des Innenraums des Schiebers erstreckt.
     
    4. Servoventil nach einem der vorhergehenden Ansprüche, wobei die Endkappen (200) eine dünne Wand umfassen, wo sie die Öffnungen überlappen.
     
    5. Servoventil nach einem der vorhergehenden Ansprüche, wobei die Öffnungen (28) eine Öffnung umfassen, die in Richtung jedes Endes des Schiebers bereitgestellt ist.
     
    6. Servoventil nach einem der vorhergehenden Ansprüche, ferner umfassend ein Antriebsmittel zum Lenken der Düse (19') als Reaktion auf das Steuersignal.
     
    7. Servoventil nach einem der vorhergehenden Ansprüche, wobei die Düse (19') an einem Ende eines Strahlrohrs (18') bereitgestellt ist, das der Ventilvorrichtung am nächsten ist und wobei Fluid von der Düse (19') über einen Empfänger in die Ventilvorrichtung geleitet wird.
     
    8. Servoventil nach Anspruch 7, wobei der Empfänger so konfiguriert ist, dass Fluid gleichmäßig über beide Seiten des Empfängers in die Fluidübertragungsventilvorrichtung eintritt, wenn sich die Düse (19') in einer mittigen Position befindet und dass mehr Fluid über den Empfänger zu einer Seite der Fluidübertragungsventilvorrichtung als zu der anderen fließt, wenn die Düse (19') in eine nichtmittige Position gelenkt wird.
     
    9. Servoventil nach Anspruch 7, wobei der Empfänger laterale Empfängerkanäle umfasst, um einen Strom zu jeder Seite der Fluidübertragungsventilvorrichtung bereitzustellen.
     
    10. Servoventil nach einem der vorhergehenden Ansprüche, wobei der Verbinder (30) integral mit der Düse (19') gebildet ist oder wobei der Verbinder (30) als separate Komponente gebildet und an die Düse (19') angebracht ist.
     
    11. Servoventil nach einem der vorhergehenden Ansprüche, wobei der Verbinder (30) einen Einlass zum Empfangen von Zuführfluid und einen Auslass in Fluidverbindung mit der Düse (19') umfasst.
     
    12. Servoventil nach einem der vorhergehenden Ansprüche, wobei die Düse (19') auf einem Strahlrohr (18') bereitgestellt ist, das innerhalb einer flexiblen Röhre (26') montiert ist, wobei die flexible Röhre (26') Bewegungen an das Strahlrohr (18') übermittelt, um die Düse (19') als Reaktion auf das Steuersignal zu lenken.
     
    13. Servoventil nach Anspruch 12, wobei das Strahlrohr (18') einen Düsenabschnitt und einen Hauptkörperabschnitt (20') umfasst.
     
    14. Servoventil nach Anspruch 13, wobei der Hauptkörperabschnitt (20') röhrenförmig ist oder wobei der Hauptkörperabschnitt (20') stangen- oder drahtförmig ist.
     


    Revendications

    1. Servo-soupape comprenant : un ensemble de soupape de transfert de fluide comprenant un orifice d'alimentation et un orifice de commande ; un tiroir de soupape mobile (4) conçu pour réguler l'écoulement de fluide depuis l'orifice d'alimentation vers l'orifice de commande en réponse à un signal de commande ; et un ensemble de tuyau de pulvérisation configuré pour déplacer axialement le tiroir de soupape (4) par rapport à l'ensemble de soupape de transfert de fluide en réponse au signal de commande pour réguler l'écoulement de fluide ; dans laquelle l'ensemble de tuyau de pulvérisation comprend une buse orientable (19') à partir de laquelle le fluide est dirigé vers les extrémités (4a, 4b) du tiroir (4) en une quantité déterminée par le signal de commande ; et dans laquelle le fluide est fourni à la buse (19') par l'intermédiaire d'une embase de connecteur (30) en communication fluidique avec l'intérieur du tiroir (4), le tiroir (4) comprenant un corps tubulaire définissant un chemin pour l'écoulement de fluide, le corps tubulaire étant fermé à chaque extrémité par un capuchon d'extrémité respectif (200) ; le tiroir (4) étant en outre pourvu d'ouvertures (28) dans le corps tubulaire par lesquels, en cours d'utilisation, du fluide pénètre à l'intérieur du tiroir (4) ; et caractérisée en ce que les capuchons d'extrémité (200) s'étendent à l'intérieur du corps tubulaire au moins dans la mesure où ils chevauchent les ouvertures (28), et dans laquelle les capuchons d'extrémité (200) sont pourvus de moyens de filtrage (201) pour filtrer le fluide provenant des ouvertures (28) lorsqu'il pénètre à l'intérieur du tiroir (4).
     
    2. Servo-soupape selon la revendication 1, dans laquelle le moyen de filtrage (201) comprend des perforations (700) formées dans le capuchon d'extrémité (200) où elles chevauchent les ouvertures.
     
    3. Servo-soupape selon les revendications 1 ou 2, dans laquelle les capuchons d'extrémité (200) comprennent une partie de tête (600) configurée pour être logée de manière étanche dans l'extrémité du tiroir et un arbre (500) s'étendant depuis la tête le long de l'intérieur du tiroir.
     
    4. Servo-soupape selon une quelconque revendication précédente, dans laquelle les capuchons d'extrémité (200) comprennent une paroi mince où ils chevauchent les ouvertures.
     
    5. Servo-soupape selon une quelconque revendication précédente, dans laquelle les ouvertures (28) comprennent une ouverture fournie vers chaque extrémité du tiroir.
     
    6. Servo-soupape selon une quelconque revendication précédente, comprenant en outre un moyen d'entraînement pour orienter la buse (19') en réponse au signal de commande.
     
    7. Servo-soupape selon une quelconque revendication précédente, dans laquelle la buse (19') est prévue à une extrémité d'un tuyau de pulvérisation (18') le plus proche de l'ensemble de soupape et le fluide de la buse (19') est dirigé dans l'ensemble de soupape par l'intermédiaire d'un récepteur.
     
    8. Servo-soupape selon la revendication 7, dans laquelle le récepteur est configuré de sorte que lorsque la buse (19') est dans une position centrale, le fluide pénètre uniformément dans l'ensemble de soupape de transfert de fluide par les deux côtés du récepteur lorsque la buse (19') est orientée vers une position décentrée, davantage de fluide s'écoule d'un côté de l'ensemble de soupape de transfert de fluide que de l'autre par l'intermédiaire du récepteur.
     
    9. Servo-soupape selon la revendication 7, dans laquelle le récepteur comprend des canaux de réception latéraux pour fournir un écoulement de chaque côté de l'ensemble de soupape de transfert de fluide.
     
    10. Servo-soupape selon une quelconque revendication précédente, dans laquelle l'embase de connecteur (30) est formée d'un seul tenant avec la buse (19') ou dans laquelle l'embase de connecteur (30) est formée en tant que composant séparé et fixée à la buse (19').
     
    11. Servo-soupape selon une quelconque revendication précédente, dans laquelle l'embase de connecteur (30) comprend une entrée pour recevoir le fluide d'alimentation et une sortie en communication fluidique avec la buse (19').
     
    12. Servo-soupape selon une quelconque revendication précédente, dans laquelle la buse (19') est prévue sur un tuyau de pulvérisation (18') monté à l'intérieur d'un tube flexible (26'), dans laquelle le tube flexible (26') confère un mouvement au tuyau de pulvérisation (18') pour orienter la buse (19') en réponse au signal de commande.
     
    13. Servo-soupape selon la revendication 12, dans laquelle le tuyau de pulvérisation (18') comprend une partie de buse et une partie de corps principal (20').
     
    14. Servo-soupape selon la revendication 13, dans laquelle la partie de corps principal (20') se présente sous la forme d'un tube ou dans laquelle la partie de corps principal (20') se présente sous la forme d'une tige ou d'un câble.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description