EP0579919B1 - Pneumatic linear drive with locking for ends of travel - Google Patents

Pneumatic linear drive with locking for ends of travel Download PDF

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Publication number
EP0579919B1
EP0579919B1 EP93107819A EP93107819A EP0579919B1 EP 0579919 B1 EP0579919 B1 EP 0579919B1 EP 93107819 A EP93107819 A EP 93107819A EP 93107819 A EP93107819 A EP 93107819A EP 0579919 B1 EP0579919 B1 EP 0579919B1
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EP
European Patent Office
Prior art keywords
piston
control piston
spring
control
piston rod
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP93107819A
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German (de)
French (fr)
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EP0579919A1 (en
Inventor
Franz Dipl.-Ing. Sperber
Arno Dipl.-Ing. Voit
Walter Dipl.-Ing. Stich
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Airbus Defence and Space GmbH
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Daimler Benz Aerospace AG
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Publication of EP0579919A1 publication Critical patent/EP0579919A1/en
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    • 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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/26—Locking mechanisms
    • F15B15/261—Locking mechanisms using positive interengagement, e.g. balls and grooves, for locking in the end positions

Definitions

  • the invention relates to a linear drive with a single-acting, pneumatic piston / cylinder unit, with at least one spring which counteracts the pneumatic force and loads the piston rod in the direction of an end position, and each with a positive, pneumatic lock for each of the two end positions of the piston rod according to the preamble of the claim 1.
  • DE-OS 36 09 765 is in contact with the surface of the piston rod during the extension movement (from left to right) under spring force until it engages in the corresponding recess when the end position is reached. In this way, it exerts a compressive and a frictional force on the piston rod, which are suitable for damping any slight vibrations that may occur.
  • the invention has for its object a pneumatic linear drive with a single-acting piston / cylinder unit, with at least one spring counteracting the pneumatic force and with a positive, pneumatic locking for each of the two end positions
  • a pneumatic linear drive with a single-acting piston / cylinder unit, with at least one spring counteracting the pneumatic force and with a positive, pneumatic locking for each of the two end positions
  • the locks for both end positions are summarized on one of diametrical sides in a recess of the piston rod lockable locking link with two acting on this control piston, resulting in a compact arrangement of the locking mechanism.
  • the first control piston which is smaller due to the pressurized cross section, is rigidly connected to the locking link and is used for locking in the pneumatically unpressurized, i.e. responsible for the spring-actuated, end position of the piston rod. With respect to a cryogenic control valve, this would preferably be the closed position of the valve.
  • the second, from the pressurized cross section larger control piston is limited translationally movable relative to the locking link on a rigidly connected to this support tube, with a support tube fixed and a housing-fixed stop are present, and a compression spring between the control piston and the locking link is arranged.
  • the power transmission between the control piston and the locking link is thus resilient, i.e. relatively soft.
  • the second, larger control piston is for locking in the pneumatically pressurized, i.e. active, end position of the piston rod is responsible, with respect to a cryogenic control valve, this would preferably be the open position.
  • valve piston Through appropriate flow channels in the area of the valve piston, the second Control piston, the support tube and the locking link in connection with the various stops ensures that the pressurization, ie the activation, of the piston / cylinder unit takes place only after the complete release of the unpressurized end position, resulting in a material-friendly, largely jamming-free operation.
  • valve piston releases an additional flow cross-section between itself and the second control piston, so that the piston rod movement takes place relatively quickly.
  • each of the two control pistons is responsible for locking in one end position and for unlocking in the opposite end position.
  • the control pistons are activated actively by pneumatic pressure on one side.
  • the locking link rests on one side under pneumatic or spring force on the surface of the piston rod and dampens any vibrations that may occur due to the normal and frictional force exerted.
  • the sub-claims 2 to 4 contain preferred embodiments of the linear drive according to claim 1.
  • the linear drive 1 shown in its essential elements is part of a cryogenic control valve, not shown, with which the flow of a liquid, frozen rocket fuel component is blocked or released.
  • the extended (left) position of the piston rod 8 and the piston 6 shown in FIG. 1 corresponds to the closed position of the control valve
  • the retracted (right) position of the piston rod 8 shown in FIGS. 3 and 4 corresponds to the open position.
  • the terms “retracted” and “extended” refer to the part of the piston rod 8 which extends from the piston 6 to the left and which is connected to the valve body of the cryogenic control valve, which is also not shown.
  • the linear drive 1 comprises the piston / cylinder unit 2, which essentially consists of the housing parts 3 and 4, the piston 6 with the sealing ring 7 and the piston rod 8.
  • the linear drive further comprises the spring 5, which is connected at its left, invisible end directly or indirectly to the piston rod 8 and loads it against the pneumatic force in the direction of its left end position.
  • the linear drive 1 also includes the entire locking mechanism, via which the piston rod movement is also controlled.
  • the housing part 3 takes up the displacement of the piston / cylinder unit 2 and supports the right-hand part of the piston rod 8, which improves the rod and piston guidance but is not absolutely necessary in terms of its overall function.
  • the housing part 4 receives the locking mechanism and carries the right end of the spring 5.
  • the central element of the lock is formed by the locking link 14, which can be moved linearly to a limited extent in its displacement 15 transversely to the piston rod 8 and which, in the end positions of the piston rod 8, alternately engages in its recesses 9, 10 from opposite sides.
  • the locking link 14 has a recess 16 which can be closed around the piston rod or open on one side transversely to the direction of movement of the locking.
  • the displacement 15 of the locking link 14 preferably has a rectangular, possibly with rounded corners or an oval cross-section, whereas the displacements of all pistons are generally circular in cross-section.
  • the locking link 14 is rigidly connected via a piston rod 19 to a first, relatively small control piston 17, which is guided gas-tight in its career by means of a sealing ring 18.
  • the control piston can be pressurized with compressed gas, preferably helium, through the channel 20 and thereby generates a force or a movement of the locking link 14 radially towards the piston rod 8.
  • a second, larger control piston 21 is arranged, which in connection with a valve piston 28 serves not only to move the locking link but also to control the gas for the actual working piston, ie the piston 6.
  • the second control piston 21 is not rigidly connected to the locking link 14, but is mounted on a supporting tube 30 which is fixed to the locking link and is axially movably limited.
  • the end position of the control piston 21 remote from the link is defined by a rigid stop 31 on the support tube 30, which interacts with the smaller diameter of a stepped bore 23 in the control piston 21. This piston position is shown in Figure 1.
  • the movement of the control piston 21 to the locking link 14 or to the piston rod 8 is limited twice, on the one hand by striking the bottom of the valve piston 28 on the end face 32 of the support tube 30, and on the other hand by the stop 39 in the housing part 4.
  • the valve piston 28 lies usually by the force of the biased Spring fingers 27 of the spring cage 25 fixedly connected to the control piston 21 on the end face 24 of the control piston 21 in a gas-tight manner, an additional sealing element, for example an O-ring, being able to be present in this area.
  • the valve piston 28 can be lifted from the end face 24 by a corresponding pressure or force action, and at most up to the abutment against the stop lugs 26 of the spring cage 25, an open flow cross section being created between the pistons 21 and 28.
  • the spring cage 25 is not a closed, pot-like structure but a flow-permeable body with several openings.
  • the pistons 21 and 28 mostly behave like an integral body, their resilient connection only comes into effect under certain conditions.
  • the power transmission from the control piston 21 to the locking link 14 takes place elastically compliant via the spring 37.
  • a relatively hard, direct power transmission only occurs in the moments when the bottom of the valve piston 28 abuts the end face 32 of the support tube 30.
  • the compressed gas supply to the piston 6 takes place through the valve piston 28 and the control piston 21, see in particular FIGS. 2 and 3.
  • This connection begins with the openings 33 in the area of the end face 32 of the support tube 30 and continues with the flow channel 36 in the interior of the support tube and with the openings 34 and 35 in the area of the locking link 14.
  • the openings 12 and 13 in the wall element 11 belong to this flow connection.
  • the number, size and arrangement of the openings and channels can be used to influence the movements of the piston rod 8, specifically depending on the position of the locking link 14 relative to the wall element 11.
  • the flow connection mentioned is always open.
  • the flow connection is interrupted from the outside (bottom) of the valve piston 28 into the interior of the pistons 28 and 21 by contacting the bottom of the valve piston 28 on the end face 32 of the support tube 30 with the throttle channel 29 closed.
  • the valve piston 28 must also lie gas-tight on the control piston 21, the latter by means of a sealing ring 22 is performed gastight in his career.
  • the flow connection from the channel 38 in the housing part 4 to the pressure side of the piston 6 is open, as shown in FIGS. 1 to 4.
  • Figure 1 shows the extended (left) and locked end position of the piston rod 8, which is brought about by the force of the spring 5.
  • the control piston 17 is pressurized with helium (see arrow), the pistons 21, 28 and 6 are "'vented", i.e. depressurized. Due to the force of the spring 37, the control piston 21 is in its outermost (lowest) position on the support tube 30 at the stop 31.
  • the control piston 17 In order to release the lock and initiate the retracting movement of the piston rod 8, the control piston 17 is “vented” and the control piston 21 is pressurized with helium. As a result of the strong throttling action of the narrow throttle duct 29, the valve piston 28, together with the control piston 21, is pushed as far as possible against the end face 32 of the support tube 30, the throttle duct 29 being closed and the spring 37 being compressed. From then on, the pistons 21 and 28 and the support tube 30 move together with the locking link 14, the part of the locking link 14 facing the control piston 17 completely moving out of the recess 10 and thus releasing the piston rod 8.
  • FIG. 3 shows the locked, retracted position of the piston rod 8 with the spring 5 pushed together to the maximum, which corresponds to the opened state of the cryogenic control valve, not shown.
  • the locking link is engaged by the force of the spring 37 in the recess 9 of the piston rod 8, the piston 6 is under pressure.
  • the pistons 21 and 28 are “vented” and the control piston 17 is pressurized, whereby the unlocking movement of the locking link 14 begins. Due to the pressure still present in the displacement of the piston 6, which extends into the area of the pistons 21 and 28, the valve piston 28 lifts off the end face 24 of the control piston 21 and releases a relatively large flow cross section via the throttle channel 29. In this way there is a rapid reduction in pressure in the displacement of the piston 6 and, after complete unlocking, a relatively rapid extension movement of the piston rod 8.
  • Figure 4 shows the moment of transition from unlocking to extending movement.
  • the locking link 14 then rests in a damping manner on the piston rod 8 until it engages in the recess 10 in the extended end position.
  • the frictional force in the damping phase is kept at a moderate level by the small pressure cross section of the control piston 17.

Abstract

Linear drive with a single-acting, pneumatic piston/cylinder unit (1), with at least one spring (5), counteracting the pneumatic force and loading the piston rod (8) in the direction of an end of travel, and one positive pneumatic locking means each for each of the two ends of travel of the piston rod (8). The locking means comprises a locking link (14) when can engage from diametral sides in one recess (9, 10) each of the piston rod (8, 10), a first control piston (17) rigidly connected to the locking link, a second, larger control piston (21) mounted in a longitudinally movable manner on a supporting tube (30) rigidly connected to the locking link (14), a spring (37) pressing the second control piston (21) in the direction of its outer end of travel, a fixed stop (39) for the second control piston (21), a valve piston (28) coupled to the second control piston in a spring-elastic and sealing manner and having a closable choke passage (29), and an open flow connection (36) from the inner space of the second control piston (21) and the valve piston (28) to the pressure space of the piston/cylinder unit (1). <IMAGE>

Description

Die Erfindung betrifft einen Linearantrieb mit einer einfachwirkenden, pneumatischen Kolben-/Zylindereinheit, mit mindestens einer der Pneumatikkraft entgegenwirkenden, die Kolbenstange in Richtung einer Endlage belastenden Feder und mit je einer formschlüssigen, pneumatischen Verriegelung für jede der beiden Endlagen der Kolbenstange gemäß dem Oberbegriff des Patentanspruches 1.The invention relates to a linear drive with a single-acting, pneumatic piston / cylinder unit, with at least one spring which counteracts the pneumatic force and loads the piston rod in the direction of an end position, and each with a positive, pneumatic lock for each of the two end positions of the piston rod according to the preamble of the claim 1.

Aus der DE-OS 36 09 765 ist ein Linearantrieb mit einer doppeltwirkenden, pneumatischen Kolben-/Zylindereinheit bekannt, welcher im Bereich beider Zylinderenden je eine formschlüssige Verriegelung für jede der beiden Endlagen der Kolbenstange aufweist. Die Verriegelung erfolgt in beiden Positionen durch Federn, welche die Verriegelungselemente in Richtung auf die Kolbenstange zu vorspannen. Die Entriegelung erfolgt pneumatisch durch Überwinden der Federkraft, wobei das Druckgas erst nach dem vollständigen Entriegeln in die Kolben-/Zylindereinheit strömen und die Kolbenstange in Bewegung setzen kann. Auf diese Weise wird eine besonders verschleiß- und geräuscharme Betätigung erzielt. Das in Fig. 1 der DE-OS 36 09 765 rechts dargestellte Verriegelungselement liegt bei der Ausfahrbewegung der Kolbenstange (von links nach rechts) unter Federkraft an deren Oberfläche an bis es bei Erreichen der Endlage in die entsprechende Ausnehmung einrastet. Auf diese Weise übt es eine Druck- und eine Reibungskraft auf die Kolbenstange aus, welche geeignet sind, ggf. auftretende, leichte Schwingungen zu dämpfen.From DE-OS 36 09 765 a linear drive with a double-acting pneumatic piston / cylinder unit is known, which has a positive lock for each of the two end positions of the piston rod in the area of both cylinder ends. The locking takes place in both positions by springs which bias the locking elements towards the piston rod. Unlocking takes place pneumatically by overcoming the spring force, whereby the compressed gas can only flow into the piston / cylinder unit after complete unlocking and can set the piston rod in motion. In this way, particularly low-wear and low-noise actuation is achieved. The locking element shown on the right in FIG. 1 of DE-OS 36 09 765 is in contact with the surface of the piston rod during the extension movement (from left to right) under spring force until it engages in the corresponding recess when the end position is reached. In this way, it exerts a compressive and a frictional force on the piston rod, which are suitable for damping any slight vibrations that may occur.

Ein gewisser Nachteil dieses Linearantriebes liegt konstruktiv bedingt in der relativ großen Baulänge.A certain disadvantage of this linear drive is the relatively large overall length due to its design.

Ausgehend von dieser bekannten Lösung für einen doppeltwirkenden, pneumatischen Linearantrieb liegt der Erfindung die Aufgabe zugrunde, einen pneumatischen Linearantrieb mit einer einfachwirkenden Kolben-/Zylindereinheit, mit mindestens einer der Pneumatikkraft entgegenwirkenden Feder und mit je einer formschlüssigen, pneumatischen Verriegelung für jede der beiden Endlagen der Kolbenstange zu schaffen, welcher besonders kompakt, leicht, unkompliziert und betriebssicher ist, welcher sich mit geringem Aufwand an unterschiedliche Betriebsanforderungen anpassen läßt und welcher in einem breiten Vibrationsspektrum, wie es insbesondere in der Umgebung von Raketentriebwerken auftritt, einsetzbar ist.Based on this known solution for a double-acting pneumatic linear drive, the invention has for its object a pneumatic linear drive with a single-acting piston / cylinder unit, with at least one spring counteracting the pneumatic force and with a positive, pneumatic locking for each of the two end positions To create a piston rod which is particularly compact, is light, uncomplicated and reliable, which can be adapted to different operating requirements with little effort and which can be used in a wide range of vibrations, as occurs in particular in the vicinity of rocket engines.

Diese Aufgabe wird durch die im kennzeichnenden Teil des Hauptanspruches genannten Merkmale gelöst.This object is achieved by the features mentioned in the characterizing part of the main claim.

Die Verriegelungen für beide Endlagen sind zu einer von diametralen Seiten in je eine Ausnehmung der Kolbenstange einrastbaren Verriegelungskulisse mit zwei an dieser angreifenden Steuerkolben zusammenfaßt, wodurch sich eine kompakte Anordnung der Verriegelungsmechanik ergibt. Der erste, vom druckbeaufschlagten Querschnitt her kleinere Steuerkolben ist starr mit der Verriegelungskulisse verbunden und ist für die Verriegelung in der pneumatisch drucklosen, d.h. in der federbetätigten, Endlage der Kolbenstange zuständig. Mit Bezug auf ein kryogenes Steuerventil wäre dies vorzugsweise die Geschlossen-Stellung des Ventils.The locks for both end positions are summarized on one of diametrical sides in a recess of the piston rod lockable locking link with two acting on this control piston, resulting in a compact arrangement of the locking mechanism. The first control piston, which is smaller due to the pressurized cross section, is rigidly connected to the locking link and is used for locking in the pneumatically unpressurized, i.e. responsible for the spring-actuated, end position of the piston rod. With respect to a cryogenic control valve, this would preferably be the closed position of the valve.

Der zweite, vom druckbeaufschlagten Querschnitt her größere Steuerkolben ist relativ zur Verriegelungskulisse auf einem starr mit dieser verbundenen Tragrohr begrenzt translatorisch beweglich, wobei ein tragrohrfester und ein gehäusefester Anschlag vorhanden sind, und eine Druckfeder zwischen dem Steuerkolben und der Verriegelungskulisse angeordnet ist. Somit erfolgt die Kraftübertragung zwischen Steuerkolben und Verriegelungskulisse federelastisch, d.h. relativ weich.The second, from the pressurized cross section larger control piston is limited translationally movable relative to the locking link on a rigidly connected to this support tube, with a support tube fixed and a housing-fixed stop are present, and a compression spring between the control piston and the locking link is arranged. The power transmission between the control piston and the locking link is thus resilient, i.e. relatively soft.

Der zweite, größere Steuerkolben ist für die Verriegelung in der pneumatisch druckbeaufschlagten, d.h. aktiven, Endlage der Kolbenstange zuständig, bezüglich eines kryogenen Steuerventils wäre dies vorzugsweise die Offen-Stellung.The second, larger control piston is for locking in the pneumatically pressurized, i.e. active, end position of the piston rod is responsible, with respect to a cryogenic control valve, this would preferably be the open position.

Er ist aber außerdem für die Steuerung der Druckgaszu- und -abführung zum bzw. aus dem Druckraum der Kolben-/Zylindereinheit zuständig und zu diesem Zweck mit einem zusätzlichen Ventilkolben gekoppelt. Durch entsprechende Strömungskanäle im Bereich des Ventilkolbens, des zweiten Steuerkolbens, des Tragrohres und der Verriegelungskulisse in Verbindung mit den diversen Anschlägen wird erreicht, daß die Druckbeaufschlagung, d.h. die Aktivierung, der Kolben-/Zylindereinheit erst nach dem vollständigen Entriegeln der drucklosen Endlage erfolgt, wodurch sich eine materialschonende, weitgehend klemmungsfreie Arbeitsweise ergibt.However, he is also responsible for controlling the pressure gas supply and discharge to and from the pressure chamber of the piston / cylinder unit and for this purpose is coupled to an additional valve piston. Through appropriate flow channels in the area of the valve piston, the second Control piston, the support tube and the locking link in connection with the various stops ensures that the pressurization, ie the activation, of the piston / cylinder unit takes place only after the complete release of the unpressurized end position, resulting in a material-friendly, largely jamming-free operation.

Beim Übergang von der aktiven in die passive Stellung, nach Entriegeln der aktiven Endlage, gibt der Ventilkolben zwischen sich und dem zweiten Steuerkolben einen zusätzlichen Strömungsquerschnitt frei, so daß die Kolbenstangenbewegung relativ zügig erfolgt.During the transition from the active to the passive position, after unlocking the active end position, the valve piston releases an additional flow cross-section between itself and the second control piston, so that the piston rod movement takes place relatively quickly.

Die erfindungsgemäße Anordnung hat zur Folge, daß jeder der beiden Steuerkolben für die Verriegelung in der einen Endlage und für die Entriegelung in der entgegengesetzten Endlage zuständig ist. Die Betätigung der Steuerkolben erfolgt aktiv durch einseitige pneumatische Druckbeaufschlagung. Während jeder Kolbenbewegung zwischen den Endlagen liegt die Verriegelungskulisse einseitig unter Pneumatik- bzw. Federkraft an der Kolbenstangenoberfläche an und dämpft ggf. auftretende Schwingungen durch die ausgeübte Normal- und Reibungskraft.The result of the arrangement according to the invention is that each of the two control pistons is responsible for locking in one end position and for unlocking in the opposite end position. The control pistons are activated actively by pneumatic pressure on one side. During each piston movement between the end positions, the locking link rests on one side under pneumatic or spring force on the surface of the piston rod and dampens any vibrations that may occur due to the normal and frictional force exerted.

Die Unteransprüche 2 bis 4 enthalten bevorzugte Ausgestaltungen des Linearantriebes nach Anspruch 1.The sub-claims 2 to 4 contain preferred embodiments of the linear drive according to claim 1.

Die Erfindung wird anschließend anhand der Figuren noch näher erläutert. Dabei zeigen in schematischer Darstellung:

Fig. 1
einen Teillängsschnitt durch einen Linearantrieb mit ausgefahrener, verriegelter Kolbenstange,
Fig. 2
einen Teillängsschnitt mit einfahrender, entriegelter Kolbenstange,
Fig. 3
einen Teillängsschnitt mit eingefahrener, verriegelter Kolbenstange,
Fig. 4
einen Teillängsschnitt mit eingefahrener, in der Entriegelung unmittelbar vor dem Ausfahren befindlicher Kolbenstange.
The invention is subsequently explained in more detail with reference to the figures. The following are shown in a schematic representation:
Fig. 1
a partial longitudinal section through a linear drive with extended, locked piston rod,
Fig. 2
a partial longitudinal section with retracting, unlocked piston rod,
Fig. 3
a partial longitudinal section with the piston rod retracted and locked,
Fig. 4
a partial longitudinal section with the piston rod in the unlocking position immediately before the extension.

Der in seinen wesentlichen Elementen wiedergegebene Linearantrieb 1 ist Teil eines nicht dargestellten, kryogenen Steuerventils, mit welchem der Strom einer flüssigen, tiefgekühlten Raketentreibstoffkomponente gesperrt oder freigegeben wird.The linear drive 1 shown in its essential elements is part of a cryogenic control valve, not shown, with which the flow of a liquid, frozen rocket fuel component is blocked or released.

Die in Fig. 1 gezeigte, ausgefahrene (linke) Stellung der Kolbenstange 8 und des Kolbens 6 entspricht der Geschlossen-Stellung des Steuerventils, die in den Figuren 3 und 4 gezeigte, eingefahrene (rechte) Stellung der Kolbenstange 8 der Offen-Stellung. Die Begriffe "eingefahren" und "ausgefahren" beziehen sich auf den vom Kolben 6 aus nach links verlaufenden Teil der Kolbenstange 8, welcher mit dem - ebenfalls nicht dargestellten - Ventilkörper des kryogenen Steuerventils verbunden ist. Der Linearantrieb 1 umfaßt die Kolben-/Zylindereinheit 2, welche im wesentlichen aus den Gehäuseteilen 3 und 4, dem Kolben 6 mit Dichtring 7 und der Kolbenstange 8 besteht.The extended (left) position of the piston rod 8 and the piston 6 shown in FIG. 1 corresponds to the closed position of the control valve, the retracted (right) position of the piston rod 8 shown in FIGS. 3 and 4 corresponds to the open position. The terms "retracted" and "extended" refer to the part of the piston rod 8 which extends from the piston 6 to the left and which is connected to the valve body of the cryogenic control valve, which is also not shown. The linear drive 1 comprises the piston / cylinder unit 2, which essentially consists of the housing parts 3 and 4, the piston 6 with the sealing ring 7 and the piston rod 8.

Der Linearantrieb umfaßt weiterhin die Feder 5, welche an ihrem linken, nicht sichtbaren Ende direkt oder indirekt mit der Kolbenstange 8 verbunden ist und diese entgegen der Pneumatikkraft in Richtung ihrer linken Endlage belastet.The linear drive further comprises the spring 5, which is connected at its left, invisible end directly or indirectly to the piston rod 8 and loads it against the pneumatic force in the direction of its left end position.

Der Linearantrieb 1 umfaßt ebenfalls den gesamten Verriegelungsmechanismus, über den auch die Steuerung der Kolbenstangenbewegung erfolgt. Das Gehäuseteil 3 nimmt den Hubraum der Kolben-/Zylindereinheit 2 auf und stützt den rechten Teil der Kolbenstange 8, welcher die Stangen- und Kolbenführung verbessert aber von der Gesamtfunktion her nicht zwingend erforderlich ist.The linear drive 1 also includes the entire locking mechanism, via which the piston rod movement is also controlled. The housing part 3 takes up the displacement of the piston / cylinder unit 2 and supports the right-hand part of the piston rod 8, which improves the rod and piston guidance but is not absolutely necessary in terms of its overall function.

Das Gehäuseteil 4 nimmt den Verriegelungsmechanismus auf und trägt das rechte Ende der Feder 5.The housing part 4 receives the locking mechanism and carries the right end of the spring 5.

Das zentrale Element der Verriegelung bildet die Verriegelungskulisse 14, welche in ihrem Hubraum 15 quer zur Kolbenstange 8 begrenzt linear beweglich ist und in den Endlagen der Kolbenstange 8 abwechselnd von gegenüberliegenden Seiten formschlüssig in deren Ausnehmungen 9, 10 eingreift. Zu diesem Zweck weist die Verriegelungskulisse 14 eine Aussparung 16 auf, welche rund um die Kolbenstange geschlossen oder quer zur Bewegungsrichtung der Verriegelung einseitig offen sein kann. Der Hubraum 15 der Verriegelungskulisse 14 weist vorzugsweise einen rechteckigen, ggf. mit gerundeten Ecken versehenen oder einen ovalen Querschnitt auf, wohingegen die Hubräume aller vorhandenen Kolben in aller Regel im Querschnitt kreisförmig ausgeführt sind. Die Verriegelungskulisse 14 ist über eine Kolbenstange 19 starr mit einem ersten, relativ kleinen Steuerkolben 17 verbunden, welcher mittels eines Dichtringes 18 in seiner Laufbahn gasdicht geführt ist. Der Steuerkolben kann,wie in den Figuren 1 und 4 mit weißen Pfeilen angedeutet, durch den Kanal 20 mit Druckgas, vorzugsweise Helium, beaufschlagt werden und erzeugt dadurch eine Kraft bzw. eine Bewegung der Verriegelungskulisse 14 radial zur Kolbenstange 8 hin.The central element of the lock is formed by the locking link 14, which can be moved linearly to a limited extent in its displacement 15 transversely to the piston rod 8 and which, in the end positions of the piston rod 8, alternately engages in its recesses 9, 10 from opposite sides. For this purpose, the locking link 14 has a recess 16 which can be closed around the piston rod or open on one side transversely to the direction of movement of the locking. The displacement 15 of the locking link 14 preferably has a rectangular, possibly with rounded corners or an oval cross-section, whereas the displacements of all pistons are generally circular in cross-section. The locking link 14 is rigidly connected via a piston rod 19 to a first, relatively small control piston 17, which is guided gas-tight in its career by means of a sealing ring 18. As indicated in FIGS. 1 and 4 with white arrows, the control piston can be pressurized with compressed gas, preferably helium, through the channel 20 and thereby generates a force or a movement of the locking link 14 radially towards the piston rod 8.

Auf der dem Steuerkolben 17 gegenüberliegenden, in den Figuren unteren Seite ist ein zweiter, größerer Steuerkolben 21 angeordnet, welcher in Verbindung mit einem Ventilkolben 28 nicht nur zur Bewegung der Verriegelungskulisse sondern auch zur Gassteuerung für den eigentlichen Arbeitskolben, d.h. den Kolben 6, dient. Der zweite Steuerkolben 21 ist im Unterschied zum ersten (17) nicht starr mit der Verriegelungskulisse 14 verbunden sondern auf einem verriegelungskulissenfesten Tragrohr 30 begrenzt axial beweglich gelagert. Die kulissenferne Endlage des Steuerkolbens 21 wird durch einen starren Anschlag 31 am Tragrohr 30 definiert, welcher mit dem kleineren Durchmesser einer Stufenbohrung 23 im Steuerkolben 21 zusammenwirkt. Diese Kolbenstellung ist in Figur 1 gezeigt. Die Bewegung des Steuerkolbens 21 zur Verriegelungskulisse 14 bzw. zur Kolbenstange 8 hin wird zweifach begrenzt und zwar zum einen durch Anschlagen des Bodens des Ventilkolbens 28 an der Stirnfläche 32 des Tragrohres 30, zum anderen durch den Anschlag 39 im Gehäuseteil 4. Der Ventilkolben 28 liegt normalerweise durch die Kraft der vorgespannten Federfinger 27 des fest mit dem Steuerkolben 21 verbundenen Federkäfigs 25 gasdicht an der Stirnfläche 24 des Steuerkolbens 21 an, wobei in diesem Bereich ein zusätzliches Dichtelement, z.B. ein O-Ring, vorhanden sein kann. Durch entsprechende Druck- bzw. Krafteinwirkung kann der Ventilkolben 28 von der Stirnfläche 24 abgehoben werden und zwar maximal bis zum Anliegen an den Anschlagnasen 26 des Federkäfigs 25, wobei zwischen den Kolben 21 und 28 ein offener Strömungsquerschnitt entsteht. Dieser Fall ist in Fig. 4 dargestellt. Es sei darauf hingewiesen, daß der Federkäfig 25 kein geschlossenes, topfartiges Gebilde sondern einen strömungsdurchlässigen Körper mit mehreren Durchbrüchen darstellt. Somit verhalten sich die Kolben 21 und 28 zumeist wie ein integraler Körper, nur unter bestimmten Verhältnissen kommt deren federelastische Verbindung zur Wirkung.On the opposite side of the control piston 17 in the figures, a second, larger control piston 21 is arranged, which in connection with a valve piston 28 serves not only to move the locking link but also to control the gas for the actual working piston, ie the piston 6. In contrast to the first (17), the second control piston 21 is not rigidly connected to the locking link 14, but is mounted on a supporting tube 30 which is fixed to the locking link and is axially movably limited. The end position of the control piston 21 remote from the link is defined by a rigid stop 31 on the support tube 30, which interacts with the smaller diameter of a stepped bore 23 in the control piston 21. This piston position is shown in Figure 1. The movement of the control piston 21 to the locking link 14 or to the piston rod 8 is limited twice, on the one hand by striking the bottom of the valve piston 28 on the end face 32 of the support tube 30, and on the other hand by the stop 39 in the housing part 4. The valve piston 28 lies usually by the force of the biased Spring fingers 27 of the spring cage 25 fixedly connected to the control piston 21 on the end face 24 of the control piston 21 in a gas-tight manner, an additional sealing element, for example an O-ring, being able to be present in this area. The valve piston 28 can be lifted from the end face 24 by a corresponding pressure or force action, and at most up to the abutment against the stop lugs 26 of the spring cage 25, an open flow cross section being created between the pistons 21 and 28. This case is shown in Fig. 4. It should be noted that the spring cage 25 is not a closed, pot-like structure but a flow-permeable body with several openings. Thus, the pistons 21 and 28 mostly behave like an integral body, their resilient connection only comes into effect under certain conditions.

Die Kraftübertragung vom Steuerkolben 21 zur Verriegelungskulisse 14 hin erfolgt elastisch nachgiebig über die Feder 37. Eine relativ harte, direkte Kraftübertragung ergibt sich nur in den Momenten, in denen der Boden des Ventilkolbens 28 an der Stirnfläche 32 des Tragrohres 30 anliegt.The power transmission from the control piston 21 to the locking link 14 takes place elastically compliant via the spring 37. A relatively hard, direct power transmission only occurs in the moments when the bottom of the valve piston 28 abuts the end face 32 of the support tube 30.

Die Druckgasversorgung des Kolbens 6 erfolgt durch den Ventilkolben 28 und den Steuerkolben 21 hindurch, siehe hierzu insbesondere die Figuren 2 und 3. Es besteht eine ständig offene Strömungsverbindung vom Innenraum der Kolben 21 und 28 zum Hubraum 15 der Verriegelungskulisse 14 und von dort weiter durch das Wandelement 11 hindurch zur Druckseite (links) des Kolbens 6. Diese Verbindung beginnt mit den Öffnungen 33 im Bereich der Stirnfläche 32 des Tragrohres 30 und setzt sich fort mit dem Strömungskanal 36 im Tragrohrinneren sowie mit den Öffnungen 34 und 35 im Bereich der Verriegelungskulisse 14. Weiterhin gehören die Öffnungen 12 und 13 im Wandelement 11 zu dieser Strömungsverbindung. Über Anzahl, Größe und Anordnung der Öffnungen und Kanäle lassen sich die Bewegungsabläufe der Kolbenstange 8 beeinflussen und zwar auch gezielt in Abhängigkeit von der Stellung der Verriegelungskulisse 14 relativ zum Wandelement 11. Wesentlich ist aber nur, daß die genannte Strömungsverbindung immer offen ist. Unterbrochen wird jedoch in bestimmten Betriebszuständen die Strömungsverbindung von der Außenseite (Unterseite) des Ventilkolbens 28 in den Innenraum der Kolben 28 und 21 und zwar durch Anlage des Boden des Ventilkolbens 28 an der Stirnfläche 32 des Tragrohres 30 unter Verschluß des Drosselkanales 29. Dabei muß der Ventilkolben 28 auch am Steuerkolben 21 gasdicht anliegen, wobei letzterer mittels eines Dichtringes 22 in seiner Laufbahn gasdicht geführt ist. In der Mehrzahl der Betriebszustände ist die Strömungsverbindung vom Kanal 38 im Gehäuseteil 4 bis zur Druckseite des Kolbens 6 jedoch offen, wie in den Fig. 1 bis 4 gezeigt.The compressed gas supply to the piston 6 takes place through the valve piston 28 and the control piston 21, see in particular FIGS. 2 and 3. There is a constantly open flow connection from the interior of the pistons 21 and 28 to the displacement 15 of the locking link 14 and from there through the Wall element 11 through to the pressure side (left) of the piston 6. This connection begins with the openings 33 in the area of the end face 32 of the support tube 30 and continues with the flow channel 36 in the interior of the support tube and with the openings 34 and 35 in the area of the locking link 14. Furthermore, the openings 12 and 13 in the wall element 11 belong to this flow connection. The number, size and arrangement of the openings and channels can be used to influence the movements of the piston rod 8, specifically depending on the position of the locking link 14 relative to the wall element 11. It is only essential, however, that the flow connection mentioned is always open. However, in certain operating states, the flow connection is interrupted from the outside (bottom) of the valve piston 28 into the interior of the pistons 28 and 21 by contacting the bottom of the valve piston 28 on the end face 32 of the support tube 30 with the throttle channel 29 closed. The valve piston 28 must also lie gas-tight on the control piston 21, the latter by means of a sealing ring 22 is performed gastight in his career. In the majority of the operating states, however, the flow connection from the channel 38 in the housing part 4 to the pressure side of the piston 6 is open, as shown in FIGS. 1 to 4.

Zum besseren Verständnis wird anschließend noch näher auf die Betriebszustände gemäß den Figuren 1 bis 4 sowie auf deren Zusammenhänge eingegangen.For a better understanding, the operating states according to FIGS. 1 to 4 and their relationships are discussed in more detail below.

Figur 1 zeigt die ausgefahrene (linke) und verriegelte Endlage der Kolbenstange 8, welche durch die Kraft der Feder 5 herbeigeführt wird. Zur Sicherung der Verriegelung wird der Steuerkolben 17 mit Druckhelium beaufschlagt (siehe Pfeil), die Kolben 21, 28 und 6 sind "'entlüftet", d.h. drucklos. Durch die Kraft der Feder 37 befindet sich der Steuerkolben 21 in seiner äußersten (untersten) Stellung auf dem Tragrohr 30 am Anschlag 31.Figure 1 shows the extended (left) and locked end position of the piston rod 8, which is brought about by the force of the spring 5. To secure the locking, the control piston 17 is pressurized with helium (see arrow), the pistons 21, 28 and 6 are "'vented", i.e. depressurized. Due to the force of the spring 37, the control piston 21 is in its outermost (lowest) position on the support tube 30 at the stop 31.

Um die Verriegelung zu lösen und die Einfahrbewegung der Kolbenstange 8 einzuleiten, wird der Steuerkolben 17 "'entlüftet", und der Steuerkolben 21 mit Druckhelium beaufschlagt. Infolge der starken Drosselwirkung des engen Drosselkanals 29 wird der Ventilkolben 28, zusammen mit dem Steuerkolben 21, bis zum Anschlag an die Stirnfläche 32 des Tragrohres 30 geschoben, wobei der Drosselkanal 29 verschlossen, die Feder 37 zusammengedrückt wird. Ab dann bewegen sich die Kolben 21 und 28 und das Tragrohr 30 mit der Verriegelungskulisse 14 gemeinsam, wobei der dem Steuerkolben 17 zugewandte Teil der Verriegelungskulisse 14 vollständig aus der Ausnehmung 10 herausfährt und somit die Kolbenstange 8 freigibt. Der Steuerkolben 21 stößt schließlich an den gehäusefesten Anschlag 39 und bleibt stehen, das Tragrohr 30 bewegt sich zusammen mit der Verriegelungskulisse 14 weiter bis zum Anschlag an der Kolbenstange 8, wobei der Drosselkanal 29 wieder freigegeben wird und Druckhelium zum Kolben 6 strömen und die Einfahrbewegung einleiten kann. Dieser Zustand ist in Figur 2 dargestellt.In order to release the lock and initiate the retracting movement of the piston rod 8, the control piston 17 is “vented” and the control piston 21 is pressurized with helium. As a result of the strong throttling action of the narrow throttle duct 29, the valve piston 28, together with the control piston 21, is pushed as far as possible against the end face 32 of the support tube 30, the throttle duct 29 being closed and the spring 37 being compressed. From then on, the pistons 21 and 28 and the support tube 30 move together with the locking link 14, the part of the locking link 14 facing the control piston 17 completely moving out of the recess 10 and thus releasing the piston rod 8. The control piston 21 finally abuts the stop 39 fixed to the housing and stops, the support tube 30 moves together with the locking link 14 as far as the stop on the piston rod 8, the throttle channel 29 being released again and pressure helium to the piston 6 can flow and initiate the entry movement. This state is shown in Figure 2.

Bis zum Anschlag des Steuerkolbens 21 im Gehäuseteil 4 ist noch kaum Druckhelium zum Kolben 6 geströmt, so daß die Entriegelung weitgehend klemmungsfrei erfolgt.Up to the stop of the control piston 21 in the housing part 4, hardly any pressure helium has flowed to the piston 6, so that the unlocking takes place largely without jamming.

Figur 3 zeigt die verriegelte, eingefahrene Stellung der Kolbenstange 8 mit maximal zusammengeschobener Feder 5, welche dem geöffneten Zustand des nicht dargestellten kryogenen Steuerventils entspricht. Die Verriegelungskulisse ist durch die Kraft der Feder 37 in die Ausnehmung 9 der Kolbenstange 8 eingerastet, der Kolben 6 steht unter Druck.FIG. 3 shows the locked, retracted position of the piston rod 8 with the spring 5 pushed together to the maximum, which corresponds to the opened state of the cryogenic control valve, not shown. The locking link is engaged by the force of the spring 37 in the recess 9 of the piston rod 8, the piston 6 is under pressure.

Um nun wiederum diese Verriegelung zu lösen und die Ausfahrbewegung einzuleiten, werden die Kolben 21 und 28 "entlüftet", und der Steuerkolben 17 mit Druck beaufschlagt, wodurch die Entriegelungsbewegung der Verriegelungskulisse 14 beginnt. Durch den im Hubraum des Kolbens 6 noch vorhandenen Druck, welcher sich bis in den Bereich der Kolben 21 und 28 ausbreitet, hebt der Ventilkolben 28 von der Stirnfläche 24 des Steuerkolbens 21 ab und gibt über den Drosselkanal 29 hinaus einen relativ großen Strömungsquerschnitt frei. Auf diese Weise erfolgt ein zügiger Druckabbau im Hubraum des Kolbens 6 und, nach vollständiger Entriegelung, eine relativ schnelle Ausfahrbewegung der Kolbenstange 8.In order to release this lock again and initiate the extension movement, the pistons 21 and 28 are “vented” and the control piston 17 is pressurized, whereby the unlocking movement of the locking link 14 begins. Due to the pressure still present in the displacement of the piston 6, which extends into the area of the pistons 21 and 28, the valve piston 28 lifts off the end face 24 of the control piston 21 and releases a relatively large flow cross section via the throttle channel 29. In this way there is a rapid reduction in pressure in the displacement of the piston 6 and, after complete unlocking, a relatively rapid extension movement of the piston rod 8.

Figur 4 zeigt den Moment des Überganges von der Entriegelung zur Ausfahrbewegung.Figure 4 shows the moment of transition from unlocking to extending movement.

Im weiteren Verlauf legt sich die Verriegelungskulisse 14 dann wieder dämpfend an die Kolbenstange 8 an, bis sie in der ausgefahrenen Endlage in die Ausnehmung 10 einrastet. Die Reibungskraft in der Dämpfungsphase wird durch den kleinen Druckquerschnitt des Steuerkolbens 17 auf einem mäßigen Niveau gehalten.In the further course, the locking link 14 then rests in a damping manner on the piston rod 8 until it engages in the recess 10 in the extended end position. The frictional force in the damping phase is kept at a moderate level by the small pressure cross section of the control piston 17.

Claims (4)

  1. Linear drive, in particular for cryogenic control valves in liquid fuel lines of rocket engines, having a single-action, pneumatic piston/cylinder unit, having at least one spring which counteracts the pneumatic force and loads the piston rod in the direction of an end position, and having in each case a positive-locking, pneumatic interlock for each of the two end positions of the piston rod, characterized by an interlock link (14) which is movable transversely to the piston rod (8) and can be engaged from diametrically opposite sides in each case in a recess (9, 10) in the piston rod (8), by a first control piston (17) rigidly connected to the interlock link (14), by a second control piston (21) which is mounted so as to be longitudinally movable on a bearing tube (30) rigidly connected to the interlock link (14) and whose pressurized cross-section is greater than that of the first control piston (17), by at least one spring (37), which presses the second control piston (21) in the direction of its outer end position determined by a stop (31) on the bearing tube (30), between the control piston (21) and the interlock link (14), by a stop (39) which is fixed to the housing and limits the movement of the second control piston (21) towards the piston rod (8) of the piston/cylinder unit (2), by a valve piston (28) which is coupled to the second control piston (21), is longitudinally movable between the outer end face (24) of said second control piston and a stop (stop lugs 26) fixed to the control piston, provided with at least one central throttle channel (29), and brought by at least one spring (spring finger 27) to rest on the end face (24) of the control piston (21), by an end face (32), provided for temporary closure of the throttle channel (29) of the valve piston (28) on the outer end of the bearing tube (30), by at least one flow channel (36) inside the bearing tube (30) with in each case at least one opening (33, 34, 35) in the region of the control piston (21) and in the region of the interlock link (14), and by at least one flow connection (openings 12, 13) between the stroke space (15) of the interlock link (14) and the pressure space of the piston/cylinder unit (2).
  2. Linear drive according to Claim 1, characterized by at least one elastic sealing element in the contact region of the valve piston on the second control piston.
  3. Linear drive according to Claim 1 or 2, characterized by in each case at least one elastic sealing element (sealing rings 7, 18, 22) for sealing the piston (6) of the piston/cylinder unit (2) and the first (17) and the second control piston (21) in their cylindrical running surfaces.
  4. Linear drive according to one or more of Claims 1 to 3, characterized by an integral design of the stop (stop lugs 26) fixed to the control piston and the spring (spring finger 27) for the valve piston (28) as a spring cage (25).
EP93107819A 1992-06-27 1993-05-13 Pneumatic linear drive with locking for ends of travel Expired - Lifetime EP0579919B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4221230 1992-06-27
DE4221230A DE4221230C1 (en) 1992-06-27 1992-06-27

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EP0579919B1 true EP0579919B1 (en) 1995-12-20

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Publication number Priority date Publication date Assignee Title
DE4323846C1 (en) * 1993-07-16 1994-11-10 Deutsche Aerospace Pneumatic linear drive with end-position locking
FR2735539B1 (en) * 1995-06-16 1997-08-22 Henri Berthier DOUBLE-ACTING PRESSURE FLUID CYLINDER HAVING A LOCK OF THE ROD OF ITS PISTON
FR2743518B1 (en) * 1996-01-12 1998-04-17 Robotic Sa IMPROVEMENT FOR MOBILE PILOT HOLDER
DE19828199C2 (en) * 1998-06-25 2000-04-20 Daimler Chrysler Ag Shut-off valve
DE19841631C2 (en) * 1998-09-11 2002-02-28 Daimler Chrysler Ag Pneumatic linear actuator for cryogenic control valves
IT1391300B1 (en) * 2008-10-17 2011-12-01 Biesse Spa POLISHING GROUP FOR A MACHINE FOR WORKING EDGES IN GLASS, MARBLE AND SIMILAR STONE MATERIALS
CN101858371B (en) * 2010-05-25 2013-08-21 中航飞机起落架有限责任公司 Actuator cylinder with in-built manual-operated emergent unlocking device
CN102400973B (en) * 2011-11-18 2015-07-08 北京市三一重机有限公司 Hydraulic cylinder
US20140352289A1 (en) * 2012-01-13 2014-12-04 Norgen Gmbh Position adjustment and position locking of a fluid operated actuator
DE102017126196A1 (en) * 2017-11-09 2019-05-09 Arianegroup Gmbh Spring-supported, lockable linear drive and a valve equipped with it
CN111636979B (en) * 2020-06-08 2021-05-25 安徽九州云箭航天技术有限公司 Switch and flow regulating valve for liquid oxygen main circuit of pump pressure variable thrust liquid rocket engine
DE102021108820A1 (en) 2021-04-08 2022-10-13 Fte Automotive Gmbh Hydraulic parking lock actuator

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US2130618A (en) * 1936-09-03 1938-09-20 Westinghouse Air Brake Co Fluid pressure motor and locking means therefor
US2908251A (en) * 1955-05-13 1959-10-13 Gratzmuller Jean Louis Single acting hydraulic motor
CH353428A (en) * 1957-06-04 1961-04-15 Sprecher & Schuh Ag Pressure medium-operated drive for electrical switching devices
DE2146592A1 (en) * 1971-09-17 1973-03-22 Westinghouse Bremsen Apparate PRESSURIZED WORK CYLINDER WITH END-POSITIONING LOCK
DE3609765A1 (en) * 1986-03-22 1987-09-24 Colt Int Holdings PRESSURE-OPERATING LIFT CYLINDER FOR PREFERRED VENTILATION DEVICES
DE3913009C2 (en) * 1989-04-20 1994-08-11 Wolfgang Dipl Ing Niemann Pneumatic cylinder with end position locking

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DE4221230C1 (en) 1993-07-08
JP2929568B2 (en) 1999-08-03
JPH06159140A (en) 1994-06-07
EP0579919A1 (en) 1994-01-26
ATE131910T1 (en) 1996-01-15

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