EP0111617B1 - Fluid-pressure actuated activating device with locking member - Google Patents

Fluid-pressure actuated activating device with locking member Download PDF

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Publication number
EP0111617B1
EP0111617B1 EP83100503A EP83100503A EP0111617B1 EP 0111617 B1 EP0111617 B1 EP 0111617B1 EP 83100503 A EP83100503 A EP 83100503A EP 83100503 A EP83100503 A EP 83100503A EP 0111617 B1 EP0111617 B1 EP 0111617B1
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EP
European Patent Office
Prior art keywords
chamber
piston
pressure
valve
pressure medium
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
Application number
EP83100503A
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German (de)
French (fr)
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EP0111617A1 (en
Inventor
Steffen Paulo Russak
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.)
Sulzer AG
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Gebrueder Sulzer AG
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Publication date
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Publication of EP0111617A1 publication Critical patent/EP0111617A1/en
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Publication of EP0111617B1 publication Critical patent/EP0111617B1/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • 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
    • 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
    • F15B15/262—Locking mechanisms using friction, e.g. brake pads

Definitions

  • the invention relates to a pressure medium-actuated servomotor arrangement according to the preamble of claim 1.
  • Such a servomotor arrangement is known from EP-A 0104272 (priority: 17.9.82; publication date: 4.4.84). Such servomotor arrangements are used in connection with steam isolation valves in nuclear plants, in which high safety requirements are placed on the functioning of the valves.
  • the invention has for its object to develop the servomotor arrangement of the type mentioned in such a way that the valve closes when a control signal indicating a malfunction occurs, regardless of whether pressure medium is present in the valve chamber or not, and that the valve - in the absence of the control signal just mentioned - in the position in which it is currently being held open, even when there is no pressure medium in the valve chamber.
  • the closure part can be held in the respective position with the aid of the locking member, since this is acted upon by the pressure medium from the further independent pressure medium source.
  • the closure part can move into its safety position in the direction of the closed position under the influence of its own weight, since the second control valve relieves the pressure chamber of the locking member under the influence of the control signal.
  • a further pressure medium-actuated, generically different servomotor arrangement in which a locking member which is displaceable transversely to the displacement direction of the piston is provided for holding the piston.
  • the piston-like locking member is in the fixed position with its cylindrical surface on a stop attached to the piston rod; the locking member thus does not protrude with a curved end face into a corresponding recess in the piston rod.
  • the locking member is acted upon not only by a pressure medium when it is to assume the holding position, but also when it is to be moved from this position into the relief position in order to release the locking position of the piston. An external energy supply is therefore necessary for the latter manipulation.
  • the known servomotor arrangement is therefore also not suitable for achieving the object on which the invention is based.
  • the design and dimensioning of the locking member according to claim 2 prevents the necessary displacement of the piston into a safety position by the locking member.
  • a particularly simple embodiment of the locking member is contained in claim 3, by which it is avoided that the locking member slides on a surface.
  • the design of the locking member according to claim 4 allows the piston to be held by only a small axial load on the locking member, since the holding force is largely absorbed by the guide of the small piston.
  • a servomotor arrangement 1 has a movable system 2 which comprises a piston 4 which can be axially displaced in a cylinder 3, a piston rod 7 and a closure part 40.
  • a cylindrical extension 5 is provided on the piston 4 on its upper side in FIG. 1, which cooperates with a locking member 10, which is accommodated in a cover 35 of the cylinder 3.
  • the locking member 10 has a surface 11 which delimits a pressure chamber 12 which is connected via a bore 13 and a pressure medium line 14 to a steam generator 16 acting as a first pressure medium source.
  • Arranged in the bore 13 are two check valves 15 connected in series, which have a strong throttling effect when the pressure medium flows towards the pressure chamber 12 and block a pressure medium flow towards the steam generator 16.
  • a bore 17, 17 ' which contains two series-connected check valves 18 and opens into a piston chamber 6 of the servomotor arrangement.
  • the bore 17, 17 ' is connected via a cranked bore 19, which branches between the check valves 15 and 18, with the atmosphere acting as a pressure medium sink.
  • the cover 35 is fastened in a gas-tight manner to an upper end face 24 of the cylinder 3 by means of screws, not shown.
  • the bore 19 is drilled from the outside, forming a valve seat 19 ', and this bore is surrounded by a threaded blind hole.
  • a connection piece 21 of a solenoid valve 20 (second control valve) is screwed into this blind hole, which lies here in the connection between the pressure chamber 12 and the pressure medium sink (atmosphere).
  • the solenoid valve 20 contains a DC coil 22 and an axially displaceable part 23, which consists of a spindle 24, a collar 25 and an armature 26.
  • a compression spring 28, which acts on the collar 25, is supported on the bottom of the threaded blind hole.
  • the DC coil 22 is connected to a control signal line 29.
  • the servomotor arrangement 1 comprises a valve which is open in the normal position and which has a housing 30 which encloses a valve chamber 33, which forms a piece with the cylinder 3 and is connected to an inlet connector 31 and an outlet connector 32.
  • the piston rod 7 on the lower piston side in FIG. 1 extends through the piston chamber 6 and a wall 8 separating this chamber from the valve chamber 33.
  • the piston rod 7 carries the closure part 40, which has a peripheral sealing surface 42, which has a Valve seat 44 cooperates in the valve chamber 33, which forms a pressure medium source that is independent of the pressure medium source 16.
  • the piston 4 is provided on its side facing away from the piston rod 7 near the circumference with a rear seat seal 36, which cooperates in a sealing manner with a counter surface on the cover 35, so that in the uppermost position of the piston 4, which corresponds to the normal operating position, a piston chamber 9 with respect to that Piston chamber 6 is sealed.
  • the piston chamber 6 and the valve chamber 33 are connected via a U-shaped bore 37 to an adjustable throttle 38 in the form of a screw.
  • the sections of the bore 37 shown in FIG. 1 in the same plane of the drawing actually run spatially, so that the throttle 38 can be adjusted from the outside.
  • the piston chamber 9 is connected to the atmosphere via a bore 48 and an adjustable throttle 49 designed as a hollow screw.
  • the bore 37 is connected to a chamber 51 in the wall of the cylinder 3 via a U-shaped bore 50, which branches off between the valve chamber 33 and the throttle 38.
  • the bore 48 is also connected to this chamber 51 via a cranked bore 50 'and 50 ".
  • the chamber 51 contains a small piston 52 which carries a support piston 57 via a conical transition piece and a cylindrical neck.
  • the piston 52 is in one cylinder chamber 53 adjoining chamber 51, which is connected via a bore 54 to the section of bore 37 leading from throttle 38 to piston chamber 6, so that there is a permanent, unthrottled connection between cylinder chamber 53 and piston chamber 6.
  • Support piston 57 is guided in a section of the bore 50 ′′ which is elongated upward in FIG. 1 and has a considerably smaller diameter than the cylinder space 53 and is connected to the atmosphere via a bore 56.
  • the conical transition piece on the piston 52 acts as a closure body against a seat which is formed on the edge between the bore 50 ′′ and the chamber 51.
  • the closure part 40 of the valve is in its normal position, ie the valve is open, and a pressure medium flows through the inlet connector 31 and the valve chamber 33 into the outlet connector 32; the valve chamber 33 is therefore under pressure.
  • the same pressure prevails in the piston chamber 6 as in the valve chamber 33, since this communicates with the piston chamber 6 via the bore 37 and the throttle 38.
  • the pressure in the piston chamber 6 also acts in the cylinder chamber 53 and thus on the piston 52.
  • the same pressure is also effective via the bore 50 in the chamber 51 and loads part of the coni see transition piece of the piston 52.
  • the piston 52 acts on a fictitious circular area with the diameter of the bore 50 ′′ on the one hand the medium pressure upwards and on the other hand the atmospheric pressure downwards.
  • the solenoid valve 20 When the solenoid valve 20 is closed, the higher of the pressures occurring in the two pressure medium sources, namely the chamber 33 and the steam generator 16, prevail in the bore 13 and in the pressure chamber 12 because of the check valves 15 and 18. As a result, the locking member 10 is pressed against the extension 5 and the movable system 2 is held in the normal position shown, for as long as at least one of the two pressure medium sources is under sufficiently high pressure. Even if the pressure of both pressure medium sources should drop, the check valves 15 and 18 still maintain the pressure and the effectiveness of the locking member 10 for a limited time, provided the solenoid valve 20 remains closed.
  • the compression spring 28 pushes the displaceable part 23 in FIG. 1 to the left, so that the blocking of the bore 19 is released, and pressure medium flows out of the piston chamber 6 and out of the pressure chamber 12 into the atmosphere. Since not enough pressure medium can flow from the valve chamber 33 into the piston chamber 6 because of the throttle 38, the pressure drops in the piston chamber 6 and in the cylinder chamber 53. However, since the full pressure of the pressure medium flowing through the housing 30 is still present in the chamber 51, the piston 52 moves downward in FIG. 1, its conical transition piece exposing its valve cross section, so that pressure medium from the valve chamber 33 via the bore 50, the chamber 51 and the bores 50 ′′, 50 ′ and 48 flow into the piston chamber 9.
  • the path to the pressure chamber 12 to the atmosphere, via the bores 13, 17 and 19, is designed such that it is shorter and has less throttle resistance than the path from the piston chamber 6 to the atmosphere via the bore 17 ′, the check valves 18 and the bore 19.
  • the volume of the pressure chamber 12 is much smaller than that of the piston chamber 6.
  • the check valves 15 have a strong throttling effect. This ensures that when the solenoid valve 20 is opened, the locking member 10 is relieved in front of the piston chamber 6 and releases the movable system 2, thereby ensuring not only the effectiveness of the entire arrangement consisting of servomotor 1 and valve 30, but also wear the locking surfaces is avoided.
  • the coil 22 is energized, whereby the solenoid valve 20 closes; the reverse process then takes place compared to that described above. It is important that the pressure increase in the piston chamber 6 takes place very slowly because the volume of the piston chamber 6 increases continuously during the upward movement of the piston 4, so that the pressure build-up in this chamber with the aid of the pressure medium supply from the valve chamber 33 via the bore 37, to to stop the rear seat seal 36 on the counter surface, is slowed down. In contrast, pressure medium must be expelled from the piston chamber 9 into the atmosphere via the throttle 49, so that the pressure in the chamber 9 decreases only slightly during the piston movement until it stops.
  • the arrangement is designed such that the locking member 10 only engages when the piston 4 is at a standstill, which also promotes effectiveness and prevents wear.
  • valve 30 has to be kept open at a very low pressure of the pressure medium, possibly less than 1 bar, which e.g. is common in the operation of steam turbines.
  • the pressure in the valve housing 30 drops.
  • the pressure in the piston chamber 6, in the cylinder chamber 53 and in the chamber 51 also drops.
  • the piston 52 moves as soon as the pressure in the cylinder chamber 53 can no longer support it and connects it Bore 50 with the bore 50 "and 50 'and 48. Through this connection, the pressure also drops in the piston chamber 9.
  • the coil 22 lies over the control signal line 29 in tension.
  • the solenoid valve 20 remains closed.
  • the check valves 18 prevent the pressure in the bores 17, 19 and 13 between the pressure chamber 12 and the solenoid valve 20 from dropping to the pressure level in the piston chamber 6, so that the pressure determined by the steam generator 16 prevails in the region mentioned.
  • the locking member 10 remains in the locking position as long as the solenoid valve 20 is under tension. This prevents the valve 30 from closing.
  • the holding effect of the locking member 10 remains for a certain time even in the event of a failure of the steam generator 16 thanks to the action of the check valves 15 and 18.
  • the locking member 10 is arranged in the pressure area of the piston chamber 6, it is possible to dimension the locking member 10 in dependence on the existing pressures in such a way that it only comes into engagement at low pressure in the piston chamber 6 , which reduces wear.
  • the locking member 10 in such a way that the safety of the servomotor arrangement remains largely free of external influences.
  • These can consist in that the external control signal line 29 or the solenoid valve 20 is destroyed or that the valve spindle 24 is torn away even in connection with a destruction of the solenoid valve 20.
  • the servomotor and thus also the closure part 40 move into the safety position.
  • two pressure medium sources are shown.
  • FIG. 2 the locking member 10 is shown in FIG. 1 in the form of a membrane on an enlarged scale.
  • the membrane 410 has on the right side in FIG. 2 the end face 11 which is exposed to the pressure medium in the pressure chamber 12.
  • the other side of the membrane 410 runs parallel to a braking surface 101 on the extension 5 of the movable system 2, a narrow gap separating these two surfaces from one another when the membrane is not in the locking position.
  • the membrane 410 is made of a flexible material, e.g. a spring steel sheet, and is tightly welded to a fixed part of the servomotor arrangement 1, but in such a way that its flexibility and the associated mobility are still sufficiently preserved.
  • the braking surface 101 is provided on an insert 102 which is attached to the movable system 2 of the servomotor arrangement and e.g. consists of a silver-plated or nickel-plated austenitic steel sheet, which has a high coefficient of friction compared to the membrane 410.
  • the pressure medium reaches the pressure chamber 12 via the bore 13.
  • the diaphragm 410 is acted upon by the pressure medium in the pressure chamber 12 and deforms so that it is pressed against the braking surface 101 and holds the movable system 2 in place by friction.
  • the connection to the pressure medium source is interrupted and switched to a pressure medium sink, the pressure in the pressure chamber 12 drops and the membrane 410 is relaxed. Due to its own elasticity, it now resumes its original shape parallel to the braking surface 101, so that the movable system 2 is released.
  • Both a single membrane and a plurality of membranes 410 can be arranged around the extension 5. It is also possible to use a single cylindrical membrane enclosing the extension 5, which in the locking position loads the extension 5 evenly over the entire circumference.
  • the example according to FIG. 3 differs from that according to FIG. 2 in that the membrane 410 has a curvature 103 which, in the locking position, bears in a corresponding depression 104 in the extension 5. Due to the fact that the curvature 103 rests in the depression 104, forces arise which act in addition to the friction, so that a smaller pressure than in the example according to FIG. 2 is required in order to lock the movable system 2 with the same dimensions of the locking member.
  • the locking member is designed as a small cup 110.
  • the little end of the cologne is tightly connected to a corrugated tube 111, so that it is slidably guided coaxially with the corrugated tube 111 in a bore in the fixed part 67 of the servomotor arrangement 1.
  • a bearing bush 112 facilitates sliding, and a plurality of ring grooves 113 in the small cup ensure peripheral pressure compensation.
  • a collar 114 of Cologne 110 limits the stroke of C perfume by striking ring seat 115 on fixed part 67.
  • the movable system 2 has a depression 104, which, with its upper section in FIG. 4, forms a shoulder 105, against which the little cap 110 rests in its locking position with a contact surface 116.
  • a cover 117 is fastened to the fixed part 67 by screws 118, an O-ring 119 sealing this connection.
  • the corrugated tube 111 is tightly connected to the cover 117 and encloses the pressure chamber 12. This space is via the bore 13 in the cover 117 and a three-way valve 61 forming the closing element with a pressure medium source (connector 60) not shown and a pressure medium sink (connector) also not shown 62) connected.
  • the force component which acts on the support surface 116 and which influences the displacement of the small basket 110 depends on the angle ⁇ between the direction of movement of the system 2 and the support surface 116.
  • two sealing surfaces 106 and 107 are provided on the collar 114, which cooperate with corresponding seats 46 and 46 ', respectively.
  • the sealing surface 106 is pressed onto the seat 46, which prevents pressure medium from flowing through the gap between the small basket 110 and the bearing bush 112, which could cause damage.
  • the basket 110 is in the position in which the movable system 2 is free, and a pressure difference acts on the basket in the direction of the pressure chamber 12, the sealing surface 107 is pressed onto the seat 46 'and no foreign medium can exist penetrate into the bore 13. Appropriate dimensioning of the effective areas on the small cap 110 depending on the pressures present is to be carried out.
  • the locking member 210 has a spherical shape, which partly delimits the pressure chamber 12 and partly - in the locking position - lies in the recess 104 of the movable system 2. This embodiment is particularly simple and inexpensive.
  • two spherical intermediate elements 70 are arranged between the small basket 310 and the movable system.
  • the claw 310 forming part of a locking member can be displaced parallel to the direction of displacement of the movable system 2 and has two sealing seats 72 and 73 as a stroke limitation, which cooperate with corresponding mating surfaces on the fixed part 67.
  • the sealing seat 72 is located on the end face 11 of the Cologne 310, while the sealing seat 73 is located on the other end of the Cologne.
  • Piston rings 74 which seal in a known manner, are accommodated in the cylindrical guide surface of the small piston 310.
  • a plurality of balls 70 are arranged as intermediate elements between the lower end face of the cilette 310 in FIG.
  • the support surface 68 which is opposite the small basket 310, has an inclination ⁇ with respect to the direction of displacement of the system 2. The magnitude of the inclination ⁇ depends on the pressure of the pressure medium and on the position of the point of attack 75 with which the movable system 2 is supported on the balls 70 when fully engaged.
  • the support surface 68 has an edge 69 which surrounds the movable system 2 and which prevents the balls 70 from falling out when the system 2 is extended. Similar to FIG. 4, the embodiment according to FIG. 7 includes a closing element, a pressure medium source and a pressure medium sink.
  • the pressure medium passes through the bore 13 in the cover 66 into the pressure chamber 12.
  • the movable system 2 loads the balls 70 by means of the shoulder 105 in the annular groove 108, specifically in the direction from the pressure chamber 12 towards the balls 70.
  • the balls 70 absorb the load on the point of attack 75 and transfer a part thereof to the support surface 68.
  • This surface divides the force exerted on them into two components: a force component perpendicular to the support surface 68, which acts as the cause of a frictional force, and one force component parallel to the support surface 68, which — contrary to the frictional force — tries to remove the balls 70 from the movable system 2.
  • the balls 70 are prevented from moving by the small piston 310, which is held in place by the pressure medium which acts on the end face 11 in the pressure chamber 12.
  • the small piece 310 lies in a sealing manner on the associated counter surface by means of the sealing seat 73, wherein pressure medium is prevented from escaping.
  • the locking is released by connecting the pressure chamber 12 to the pressure medium sink by adjusting the closing element (not shown), as a result of which the cologne is relieved of pressure and moved upwards by the balls 70. If the pressure in the vicinity of the balls 70 exceeds that in the pressure chamber 12, the sealing seat 72 and its counter surface prevent pressure medium from flowing out via the pressure chamber 12 into the bore 13.
  • balls 70 are shown as intermediate members. However, other shaped parts can be used to do this by applying force at a particular location in a predictable direction
  • the contact between the cobs and the shoulder can be point-shaped, linear or flat, depending on the design of the contact surfaces. This makes it possible to vary the size of the surface pressure at this point within wide limits, depending on the pressures, materials and coefficients of friction available.
  • the restoring force which pushes the little boy back out of the engagement position is brought about by the movable system 2 itself, which acts on the oblique contact surface 116 or the supporting surface 68 via the shoulder 105.
  • at least one spring e.g. from Shtal, move back.

Description

Die Erfindung betrifft eine druckmittelbetätigte Stellmotoranordnung nach dem Oberbegriff des Anspruchs 1.The invention relates to a pressure medium-actuated servomotor arrangement according to the preamble of claim 1.

Es ist eine solche Stellmotoranordnung aus der EP-A 0104272 (Priorität: 17.9.82; Veröffentlichungstag: 4.4.84) bekannt. Solche Stellmotoranordnungen werden in Verbindung mit Dampfisolierventilen in Nuklearanlagen verwendet, in denen an das Funktionieren der Ventile hohe Sicherheitsanforderungen gestellt werden.Such a servomotor arrangement is known from EP-A 0104272 (priority: 17.9.82; publication date: 4.4.84). Such servomotor arrangements are used in connection with steam isolation valves in nuclear plants, in which high safety requirements are placed on the functioning of the valves.

Der Erfindung liegt die Aufgabe zugrunde, die Stellmotoranordnung der eingangs genannten Art derart weiterzubilden, dass das Ventil bei Auftreten eines eine Störung anzeigenden Steuersignals schliesst, und zwar unabhängig davon, ob Druckmittel in der Ventilkammer vorhanden ist oder nicht, und dass das Ventil - bei Fehlen des eben erwähnten Steuersignals - in der Stellung, in der es sich gerade befindet, offengehalten wird, und zwar auch dann, wenn kein Druckmittel in der Ventilkammer vorhanden ist.The invention has for its object to develop the servomotor arrangement of the type mentioned in such a way that the valve closes when a control signal indicating a malfunction occurs, regardless of whether pressure medium is present in the valve chamber or not, and that the valve - in the absence of the control signal just mentioned - in the position in which it is currently being held open, even when there is no pressure medium in the valve chamber.

Diese Aufgabe wird erfindungsgemäss durch die Merkmale des kennzeichnenden Teils des Anspruchs 1 gelöst.This object is achieved according to the invention by the features of the characterizing part of claim 1.

Durch die erfindungsgemässe Gestaltung gelingt es, bei Ausfallen der durch die Ventilkammer gebildeten Druckmittelquelle den Verschlussteil in der jeweiligen Lage mit Hilfe des Arretiergliedes zu halten, da dieses vom Druckmittel aus der weiteren unabhängigen Druckmittelquelle beaufschlagt wird. Andererseits kann bei einem Ausfallen der durch die Ventilkammer gebildeten Druckmittelquelle und beim Auftreten eines Steuersignals infolge einer Störung der Verschlussteil unter dem Einfluss seines Eigengewichtes in Richtung der Schliessstellung in seine Sicherheitsstellung fahren, da das zweite Steuerventil unter dem Einfluss des Steuersignals den Druckraum des Arretiergliedes entlastet.As a result of the design according to the invention, if the pressure medium source formed by the valve chamber fails, the closure part can be held in the respective position with the aid of the locking member, since this is acted upon by the pressure medium from the further independent pressure medium source. On the other hand, if the pressure medium source formed by the valve chamber fails and a control signal occurs as a result of a fault, the closure part can move into its safety position in the direction of the closed position under the influence of its own weight, since the second control valve relieves the pressure chamber of the locking member under the influence of the control signal.

Aus Fig. 3 der EP-A-OO 52703 ist eine einer Kolben aufweisende Stellmotoranordnung einer anderen als der eingangs vorausgesetzten Gattung bekannt. Der Kolben in dieser Anordnung wird in der Arbeitsstellung des Verschlussteils von einem kugeligen Arretierglied festgehalten, das von einer Druckfeder dauernd belastet wird. Dadurch wird es möglich, den Verschlussteil in der Arbeitsstellung zu halten, ohne am Kolben des Stellmotors eine Druckdifferenz aufrechtzuerhalten, so dass ein dauernder Mediumabfluss entlang der Kolbengleitfläche vermieden wird. Diese Anordnung hat aber den Nachteil, dass zum Lösen des Kolbens - etwa beim Übergang von der Arbeitsstellung in eine Sicherheitsstellung - eine axiale Belastung des Kolbens nötig ist, z.B. durch Aufbringen einer Druckdifferenz am Kolben des Stellmotors. Sobald höhere Sicherheitsanforderungen gestellt werden, ist eine solche Arbeitsweise nicht mehr zulässig, da die Stellmotoranordnung imstande sein muss, auch dann in die Sicherheitsstellung zu fahren, wenn z.B. kein Druckmittel zum Antrieb des Stellmotors vorhanden ist oder das Druckmittel drucklos ist.From Fig. 3 of EP-A-OO 52703 a servomotor arrangement having a piston of a type other than that initially assumed is known. The piston in this arrangement is held in the working position of the closure part by a spherical locking member which is constantly loaded by a compression spring. This makes it possible to keep the closure part in the working position without maintaining a pressure difference on the piston of the servomotor, so that a continuous medium outflow along the piston sliding surface is avoided. However, this arrangement has the disadvantage that an axial load on the piston is necessary to loosen the piston, for example when changing from the working position to a safety position, e.g. by applying a pressure difference to the piston of the servomotor. As soon as higher safety requirements are made, such a mode of operation is no longer permissible, since the servomotor arrangement must also be able to move to the safety position if, e.g. there is no pressure medium to drive the servomotor or the pressure medium is depressurized.

Aus der FR-A 1 520 585 ist eine weitere druckmittelbetätigte, gattungsmässig verschiedene Stellmotoranordnung bekannt, bei der ein quer zur Verschieberichtung des Kolbens verschiebbares Arretierglied zum Festhalten des Kolbens vorgesehen ist. Das kolbenartig ausgebildete Arretierglied liegt in der Festhaltestellung mit seiner Zylinderfläche an einem an der Kolbenstange befestigten Anschlag; das Arretierglied ragt also nicht mit einer gewölbten Stirnfläche in eine entsprechende Vertiefung der Kolbenstange. Ausserdem wird das Arretierglied nicht nur von einem Druckmittel beaufschlagt, wenn es die Festhaltestellung einnehmen soll, sondern auch dann, wenn es aus dieser Stellung in die Entlastungsstellung verschoben werden soll, um die Sperrstellung des Kolbens freizugeben. Für die zuletztgenannte Manipulation ist also eine äussere Energiezufuhr notwendig. Die bekannte Stellmotoranordnung ist also auch nicht geeignet, die der Erfindung zugrundeliegende Aufgabe zu lösen.From FR-A 1 520 585 a further pressure medium-actuated, generically different servomotor arrangement is known, in which a locking member which is displaceable transversely to the displacement direction of the piston is provided for holding the piston. The piston-like locking member is in the fixed position with its cylindrical surface on a stop attached to the piston rod; the locking member thus does not protrude with a curved end face into a corresponding recess in the piston rod. In addition, the locking member is acted upon not only by a pressure medium when it is to assume the holding position, but also when it is to be moved from this position into the relief position in order to release the locking position of the piston. An external energy supply is therefore necessary for the latter manipulation. The known servomotor arrangement is therefore also not suitable for achieving the object on which the invention is based.

Durch die Ausbildung und Bemessung des Arretiergliedes nach Anspruch 2 wird vermieden, dass ein notwendiges Verschieben des Kolbens in eine Sicherheitsstellung durch das Arretierglied verhindert wird.The design and dimensioning of the locking member according to claim 2 prevents the necessary displacement of the piston into a safety position by the locking member.

Eine besonders einfache Ausführungsform des Arretiergliedes ist im Anspruch 3 enthalten, durch die vermieden wird, dass das Arretierglied an einer Fläche gleitet.A particularly simple embodiment of the locking member is contained in claim 3, by which it is avoided that the locking member slides on a surface.

Die Ausbildung des Arretiergliedes gemäss Anspruch 4 erlaubt, den Kolben durch nur geringe axiale Belastung des Arretiergliedes festzuhalten, da die Haltekraft zum grössten Teil von der Führung des Kölbchens aufgenommen wird.The design of the locking member according to claim 4 allows the piston to be held by only a small axial load on the locking member, since the holding force is largely absorbed by the guide of the small piston.

Durch die Anordnung eines Wellrohres nach Anspruch 5 wird eine Leckage längs des Kölbchens vermieden.By arranging a corrugated pipe according to claim 5, leakage along the Cologne is avoided.

Durch die Ausführung gemäss Anspruch 6 wird auf kostengünstige Art eine Leckage längs des Kölbchens in dessen Endstellungen vermieden.Leakage along the cologne in its end positions is avoided in a cost-effective manner.

Eine Erhöhung der Haltekraft des Arretiergliedes bringt die Anordnung eines Zwischengliedes nach Anspruch 7, da durch die Umlenkung an der Stützfläche die axiale Kraft des beweglichen Systems nur noch geschwächt auf das Kölbchen wirkt. Konstruktiv besonders einfach wird diese Ausführungsform, wenn das Zwischenglied gemäss Anspruch 8 als Rollkörper ausgebildet ist.An increase in the holding force of the locking member results in the arrangement of an intermediate member according to claim 7, since the deflection on the supporting surface means that the axial force of the movable system only acts on the little boy in a weakened manner. This embodiment becomes structurally particularly simple if the intermediate member is designed as a rolling body.

Einige Ausführungsbeispiele der Erfindung werden nun anhand der Zeichnung näher erläutert. Es zeigen:

  • Fig. 1 schematisch vereinfacht einen Axialschnitt durch eine Stellmotoranordnung und ein von ihr betätigtes Ventil,
  • Fig. 2 einen Axialschnitt durch ein als Membran ausgebildetes Arretierglied,
  • Fig. 3 einen Axialschnitt durch eine gegenüber Fig. 2 abgewandelte Membran,
  • Fig. 4 einen Axialschnitt durch ein als Kölbchen ausgebildetes Arretierglied,
  • Fig. 5 einen Axialschnitt durch eine abgewandelte Ausführungsform des Kölbchens,
  • Fig. 6 einen Axialschnitt durch ein als kugelförmiges Kölbchen ausgebildetes Arretierglied und
  • Fig. 7 einen Axialschnitt durch ein Arretierglied mit Kölbchen und Zwischengliedern.
Some embodiments of the invention will now be explained in more detail with reference to the drawing. Show it:
  • 1 schematically simplified an axial section through an actuator arrangement and a valve actuated by it,
  • 2 shows an axial section through a locking member designed as a membrane,
  • 3 shows an axial section through a membrane modified compared to FIG. 2,
  • 4 shows an axial section through a locking member in the form of a bulb,
  • 5 is an axial section through a modified embodiment of the little Cologne,
  • Fig. 6 is an axial section through a locking member formed as a spherical cupper and
  • Fig. 7 is an axial section through a locking member with Cologne and intermediate members.

Gemäss Fig. 1 weist eine Stellmotoranordnung 1 ein bewegliches System 2 auf, das einen in einem Zylinder 3 axial verschiebbaren Kolben 4, eine Kolbenstange 7 und einen Verschlussteil 40 umfasst. Am Kolben 4 ist an seiner in Fig. 1 oberen Seite ein zylindrischer Fortsatz 5 vorgesehen, der mit einem Arretierglied 10 zusammenwirkt, das in einem Deckel 35 des Zylinders 3 untergebracht ist. Das Arretierglied 10 weist eine Fläche 11 auf, die einen Druckraum 12 begrenzt, der über eine Bohrung 13 und eine Druckmittelleitung 14 mit einem als erste Druckmittelquelle wirkenden Dampferzeuger 16 verbunden ist. In der Bohrung 13 sind zwei in Serie geschaltete Rückschlagventile 15 angeordnet, die bei Druckmittelströmung zum Druckraum 12 hin eine starke Drosselwirkung aufweisen und eine Druckmittelströmung zum Dampferzeuger 16 hin sperren. Von der Bohrung 13 zweigt zwischen dem Druckraum 12 einerseits und den Rückschlagventilen 15 andererseits eine Bohrung 17, 17' ab, die zwei in Serie geschaltete Rückschlagventile 18 enthält und in einen Kolbenraum 6 der Stellmotoranordnung mündet. Die Bohrung 17, 17' ist über eine gekröpft verlaufende Bohrung 19, die zwischen den Rückschlagventilen 15 und 18 abzweigt, mit der als Druckmittelsenke wirkenden Atmosphäre verbunden. Der Deckel 35 ist mittels nichtgezeichneter Schrauben auf einer oberen Stirnfläche 24 des Zylinders 3 gasdicht befestigt.1, a servomotor arrangement 1 has a movable system 2 which comprises a piston 4 which can be axially displaced in a cylinder 3, a piston rod 7 and a closure part 40. A cylindrical extension 5 is provided on the piston 4 on its upper side in FIG. 1, which cooperates with a locking member 10, which is accommodated in a cover 35 of the cylinder 3. The locking member 10 has a surface 11 which delimits a pressure chamber 12 which is connected via a bore 13 and a pressure medium line 14 to a steam generator 16 acting as a first pressure medium source. Arranged in the bore 13 are two check valves 15 connected in series, which have a strong throttling effect when the pressure medium flows towards the pressure chamber 12 and block a pressure medium flow towards the steam generator 16. From the bore 13 branches off between the pressure chamber 12 on the one hand and the check valves 15 on the other hand, a bore 17, 17 ', which contains two series-connected check valves 18 and opens into a piston chamber 6 of the servomotor arrangement. The bore 17, 17 'is connected via a cranked bore 19, which branches between the check valves 15 and 18, with the atmosphere acting as a pressure medium sink. The cover 35 is fastened in a gas-tight manner to an upper end face 24 of the cylinder 3 by means of screws, not shown.

Die Bohrung 19 ist von aussen, einen Ventilsitz 19' bildend, angebohrt, und diese Anbohrung ist von einem Gewindesackloch umgeben. In dieses Sackloch ist ein Anschlussstutzen 21 eines Magnetventils 20 (zweites Steuerventil) eingeschraubt, das hier in der Verbindung zwischen dem Druckraum 12 und der Druckmittelsenke (Atmosphäre) liegt. Das Magnetventil 20 enthält eine Gleichstromspule 22 und einen axial verschiebbaren Teil 23, der aus einer Spindel 24, einem Bund 25 und einem Anker 26 besteht. Auf dem Grunde des Gewindesackloches stützt sich eine Druckfeder 28 ab, die auf den Bund 25 einwirkt. Die Gleichstromspule 22 ist an eine Steuersignalleitung 29 angeschlossen.The bore 19 is drilled from the outside, forming a valve seat 19 ', and this bore is surrounded by a threaded blind hole. A connection piece 21 of a solenoid valve 20 (second control valve) is screwed into this blind hole, which lies here in the connection between the pressure chamber 12 and the pressure medium sink (atmosphere). The solenoid valve 20 contains a DC coil 22 and an axially displaceable part 23, which consists of a spindle 24, a collar 25 and an armature 26. A compression spring 28, which acts on the collar 25, is supported on the bottom of the threaded blind hole. The DC coil 22 is connected to a control signal line 29.

Die Stellmotoranordnung 1 umfasst ein in Normalstellung offenes Ventil, das ein eine Ventilkammer 33 umschliessendes Gehäuse 30 aufweist, das mit dem Zylinder 3 ein Stück bildet und mit einem Eintrittstutzen 31 und einem Austrittstutzen 32 verbunden ist. Die Kolbenstange 7 auf der in Fig. 1 unteren Kolbenseite erstreckt sich durch den Kolbenraum 6 und eine diesen Raum von der Ventilkammer 33 trennende Wand 8. An ihrem Ende trägt die Kolbenstange 7 den Verschlussteil 40, der eine periphere Dichtfläche 42 aufweist, die mit einem Ventilsitz 44 in der Ventilkammer 33 zusammenwirkt, die eine von der Druckmittelquelle 16 unabhängige Druckmittelquelle bildet.The servomotor arrangement 1 comprises a valve which is open in the normal position and which has a housing 30 which encloses a valve chamber 33, which forms a piece with the cylinder 3 and is connected to an inlet connector 31 and an outlet connector 32. The piston rod 7 on the lower piston side in FIG. 1 extends through the piston chamber 6 and a wall 8 separating this chamber from the valve chamber 33. At its end, the piston rod 7 carries the closure part 40, which has a peripheral sealing surface 42, which has a Valve seat 44 cooperates in the valve chamber 33, which forms a pressure medium source that is independent of the pressure medium source 16.

Der Kolben 4 ist auf seiner der Kolbenstange 7 abgewendeten Seite nahe dem Umfang mit einer Rücksitzdichtung 36 versehen, die mit einer Gegenfläche am Deckel 35 dichtend zusammenwirkt, so dass in der obersten Lage des Kolbens 4, die der Normalbetriebsstellung entspricht, ein Kolbenraum 9 gegenüber dem Kolbenraum 6 dicht abgeschlossen wird.The piston 4 is provided on its side facing away from the piston rod 7 near the circumference with a rear seat seal 36, which cooperates in a sealing manner with a counter surface on the cover 35, so that in the uppermost position of the piston 4, which corresponds to the normal operating position, a piston chamber 9 with respect to that Piston chamber 6 is sealed.

Der Kolbenraum 6 und die Ventilkammer 33 sind über eine U-förmige Bohrung 37 mit einer einstellbaren Drossel 38 in Form einer Schraube verbunden. Die in Fig. 1 in derselben Zeichenebene dargestellten Abschnitte der Bohrung 37 verlaufen in Wirklichkeit räumlich, so dass die Drossel 38 von aussen einstellbar ist.The piston chamber 6 and the valve chamber 33 are connected via a U-shaped bore 37 to an adjustable throttle 38 in the form of a screw. The sections of the bore 37 shown in FIG. 1 in the same plane of the drawing actually run spatially, so that the throttle 38 can be adjusted from the outside.

Der Kolbenraum 9 ist mit der Atmosphäre über eine Bohrung 48 und eine als Hohlschraube ausgebildete, einstellbare Drossel 49 verbunden.The piston chamber 9 is connected to the atmosphere via a bore 48 and an adjustable throttle 49 designed as a hollow screw.

Die Bohrung 37 ist über eine U-förmige Bohrung 50, die zwischen der Ventilkammer 33 und der Drossel 38 abzweigt, mit einer Kammer 51 in der Wand des Zylinders 3 verbunden. Mit dieser Kammer 51 ist auch die Bohrung 48 über eine gekröpft verlaufende Bohrung 50' und 50" verbunden. Die Kammer 51 enthält einen kleinen Kolben 52, der über ein konisches Übergangsstück und einen zylindrischen Hals einen Stützkolben 57 trägt. Der Kolben 52 ist in einem an die Kammer 51 anschliessenden Zylinderraum 53 verschiebbar, der über eine Bohrung 54 mit dem von der Drossel 38 zur Kolbenkammer 6 führenden Abschnitt der Bohrung 37 verbunden ist, so dass eine ständige, ungedrosselte Verbindung des Zylinderraumes 53 mit dem Kolbenraum 6 besteht. Der Stützkolben 57 ist in einem in Fig. 1 nach oben verlängerten Abschnitt der Bohrung 50" geführt, die einen erheblich kleineren Durchmesser als der Zylinderraum 53 aufweist und über eine Bohrung 56 mit der Atmosphäre verbunden ist. Das konische Übergangsstück am Kolben 52 wirkt als Verschlusskörper gegen einen Sitz, der an der Kante zwischen der Bohrung 50" und der Kammer 51 gebildet ist.The bore 37 is connected to a chamber 51 in the wall of the cylinder 3 via a U-shaped bore 50, which branches off between the valve chamber 33 and the throttle 38. The bore 48 is also connected to this chamber 51 via a cranked bore 50 'and 50 ". The chamber 51 contains a small piston 52 which carries a support piston 57 via a conical transition piece and a cylindrical neck. The piston 52 is in one cylinder chamber 53 adjoining chamber 51, which is connected via a bore 54 to the section of bore 37 leading from throttle 38 to piston chamber 6, so that there is a permanent, unthrottled connection between cylinder chamber 53 and piston chamber 6. Support piston 57 is guided in a section of the bore 50 ″ which is elongated upward in FIG. 1 and has a considerably smaller diameter than the cylinder space 53 and is connected to the atmosphere via a bore 56. The conical transition piece on the piston 52 acts as a closure body against a seat which is formed on the edge between the bore 50 ″ and the chamber 51.

Die Stellmotoranordnung nach Fig. 1 arbeitet wie folgt: Im Normalbetrieb liegt die Gleichstromspule 22 über die Steuersignalleitung 29 an Spannung. Der Anker 26 wird daher angezogen, wodurch die Ventilspindel 24 gegen den Ventilsitz 19' gepresst wird und die Bohrung 19 absperrt.1 operates as follows: In normal operation, the DC coil 22 is connected to voltage via the control signal line 29. The armature 26 is therefore attracted, as a result of which the valve spindle 24 is pressed against the valve seat 19 ′ and blocks the bore 19.

Der Verschlussteil 40 des Ventils ist in seiner Normalstellung, d.h. das Ventil ist geöffnet, und es strömt ein Druckmedium über den Eintrittstutzen 31 und die Ventilkammer 33 in den Austrittstutzen 32; die Ventilkammer 33 steht also unter Druck. Im Kolbenraum 6 herrscht derselbe Druck wie in der Ventilkammer 33, da diese über die Bohrung 37 und die Drossel 38 mit dem Kolbenraum 6 kommuniziert. Über die Bohrung 54 wirkt der Druck im Kolbenraum 6 auch im Zylinderraum 53 und damit auf den Kolben 52. Der gleiche Druck ist auch über die Bohrung 50 in der Kammer 51 wirksam und belastet einen Teil des konisehen Übergangsstückes des Kolbens 52. Resultierend wirkt also am Kolben 52 auf einer fiktiven Kreisfläche mit dem Durchmesser der Bohrung 50" einerseits der Mediumdruck nach oben und andererseits der Atmosphärendruck nach unten.The closure part 40 of the valve is in its normal position, ie the valve is open, and a pressure medium flows through the inlet connector 31 and the valve chamber 33 into the outlet connector 32; the valve chamber 33 is therefore under pressure. The same pressure prevails in the piston chamber 6 as in the valve chamber 33, since this communicates with the piston chamber 6 via the bore 37 and the throttle 38. Via the bore 54, the pressure in the piston chamber 6 also acts in the cylinder chamber 53 and thus on the piston 52. The same pressure is also effective via the bore 50 in the chamber 51 and loads part of the coni see transition piece of the piston 52. As a result, the piston 52 acts on a fictitious circular area with the diameter of the bore 50 ″ on the one hand the medium pressure upwards and on the other hand the atmospheric pressure downwards.

Durch diese Druckdifferenz wird das konische Übergangsstück des Kolbens 52 dichtend an seinen Sitz gepresst und ein Druckmediumfluss über die Bohrungen 50 und 50' gesperrt. Somit steht der Kolbenraum 9 über die Bohrung 48 und die Drossel 49 unter Atmosphärendruck und ist wegen der Rücksitzdichtung 36 gegen den Kolbenraum 6 abgedichtet.As a result of this pressure difference, the conical transition piece of the piston 52 is pressed tightly against its seat and a flow of pressure medium through the bores 50 and 50 'is blocked. The piston chamber 9 is thus under atmospheric pressure via the bore 48 and the throttle 49 and is sealed against the piston chamber 6 because of the rear seat seal 36.

Bei geschlossenem Magnetventil 20 herrscht - wegen der Rückschlagventile 15 und 18 - in der Bohrung 13 und im Druckraum 12 jeweils der höhere der in den beiden Druckmittelquellen, nämlich Kammer 33 und Dampferzeuger 16, auftretenden Drücke. Dadurch wird das Arretierglied 10 gegen den Fortsatz 5 gepresst und das bewegliche System 2 in der gezeichneten Normalstellung festgehalten, und zwar so lange, wie mindestens eine der beiden Druckmittelquellen unter genügend hohem Druck steht. Selbst wenn der Druck beider Druckmittelquellen absinken sollte, so sorgen die Rückschlagventile 15 und 18 noch während einer beschränkten Zeit für die Erhaltung des Druckes und für die Wirksamkeit des Arretiergliedes 10, sofern das Magnetventil 20 geschlossen bleibt.When the solenoid valve 20 is closed, the higher of the pressures occurring in the two pressure medium sources, namely the chamber 33 and the steam generator 16, prevail in the bore 13 and in the pressure chamber 12 because of the check valves 15 and 18. As a result, the locking member 10 is pressed against the extension 5 and the movable system 2 is held in the normal position shown, for as long as at least one of the two pressure medium sources is under sufficiently high pressure. Even if the pressure of both pressure medium sources should drop, the check valves 15 and 18 still maintain the pressure and the effectiveness of the locking member 10 for a limited time, provided the solenoid valve 20 remains closed.

Wird die Spannung an der Spule 22 des Magnetventils 20 abgeschaltet, so schiebt die Druckfeder 28 den verschiebbaren Teil 23 in Fig. 1 nach links, so dass die Absperrung der Bohrung 19 aufgehoben wird, und es strömt Druckmedium aus dem Kolbenraum 6 sowie aus dem Druckraum 12 in die Atmosphäre. Da wegen der Drossel 38 nicht genügend Druckmedium aus der Ventilkammer 33 in den Kolbenraum 6 nachströmen kann, sinkt im Kolbenraum 6 sowie im Zylinderraum 53 der Druck. Da in der Kammer 51 jedoch noch der volle Druck des das Gehäuse 30 durchfliessenden Druckmediums ansteht, verschiebt sich der Kolben 52 in Fig. 1 nach unten, wobei dessen konisches Übergangsstück seinen Ventilquerschnitt freigibt, so dass Druckmedium aus der Ventilkammer 33 über die Bohrung 50, die Kammer 51 und die Bohrungen 50", 50' und 48 in den Kolbenraum 9 strömt. Hierdurch baut sich im Kolbenraum 9 nahezu der in der Ventilkammer 33 herrschende Druck auf, da über die Drossel 49 weniger Druckmedium abfliessen kann, als über die Bohrung 50' zuströmt. Durch die sich nun am Kolben 4 ausbildende Druckdifferenz wird dieser nach unten verschoben, bis der Verschlussteil 40 auf dem Ventilsitz 44 sitzt und das Ventil 30 geschlossen ist.If the voltage on the coil 22 of the solenoid valve 20 is switched off, the compression spring 28 pushes the displaceable part 23 in FIG. 1 to the left, so that the blocking of the bore 19 is released, and pressure medium flows out of the piston chamber 6 and out of the pressure chamber 12 into the atmosphere. Since not enough pressure medium can flow from the valve chamber 33 into the piston chamber 6 because of the throttle 38, the pressure drops in the piston chamber 6 and in the cylinder chamber 53. However, since the full pressure of the pressure medium flowing through the housing 30 is still present in the chamber 51, the piston 52 moves downward in FIG. 1, its conical transition piece exposing its valve cross section, so that pressure medium from the valve chamber 33 via the bore 50, the chamber 51 and the bores 50 ″, 50 ′ and 48 flow into the piston chamber 9. As a result, the pressure prevailing in the valve chamber 33 almost builds up in the piston chamber 9, since less pressure medium can flow off via the throttle 49 than through the bore 50 Due to the pressure difference now forming on the piston 4, the latter is shifted downwards until the closure part 40 sits on the valve seat 44 and the valve 30 is closed.

Der Weg zum Druckraum 12 zur Atmosphäre, über die Bohrungen 13, 17 und 19 ist so ausgelegt, dass er kürzer ist und weniger Drosselwiderstand aufweist als der Weg vom Kolbenraum 6 zur Atmosphäre über die Bohrung 17', die Rückschlagventile 18 und die Bohrung 19. Ausserdem ist das Volumen des Druckraumes 12 viel kleiner als dasjenige des Kolbenraumes 6. Wie oben schon erwähnt, weisen die Rückschlagventile 15 eine starke Drosselwirkung auf. Damit wird erreicht, dass beim Öffnen des Magnetventils 20 das Arretierglied 10 noch vor dem Kolbenraum 6 entlastet wird und das bewegliche System 2 freigibt, wodurch nicht nur die Wirksamkeit der gesamten, aus Stellmotor 1 und Ventil 30 bestehenden Anordnung gewährleistet wird, sondern auch ein Verschleiss der Arretierflächen vermieden wird.The path to the pressure chamber 12 to the atmosphere, via the bores 13, 17 and 19, is designed such that it is shorter and has less throttle resistance than the path from the piston chamber 6 to the atmosphere via the bore 17 ′, the check valves 18 and the bore 19. In addition, the volume of the pressure chamber 12 is much smaller than that of the piston chamber 6. As already mentioned above, the check valves 15 have a strong throttling effect. This ensures that when the solenoid valve 20 is opened, the locking member 10 is relieved in front of the piston chamber 6 and releases the movable system 2, thereby ensuring not only the effectiveness of the entire arrangement consisting of servomotor 1 and valve 30, but also wear the locking surfaces is avoided.

Zum Wiederöffnen des Ventils 30 wird die Spule 22 an Spannung gelegt, wodurch das Magnetventil 20 schliesst; es findet dann der umgekehrte Vorgang gegenüber dem oben beschriebenen statt. Wichtig ist dabei, dass die Druckzunahme im Kolbenraum 6 sehr langsam stattfindet, weil während der Aufwärtsbewegung des Kolbens 4 das Volumen des Kolbenraumes 6 kontinuierlich zunimmt, so dass der Druckaufbau in diesem Raum mit Hilfe der Druckmittelzufuhr aus der Ventilkammer 33 über die Bohrung 37, bis zum Anschlag der Rücksitzdichtung 36 an der Gegenfläche, verlangsamt wird. Aus dem Kolbenraum 9 muss dagegen Druckmittel über die Drossel 49 in die Atmosphäre ausgestossen werden, so dass während der Kolbenbewegung bis zum Anschlag der Druck im Raum 9 nur wenig abnimmt. Es folgt also, dass die Druckzunahme im Druckraum 12 - vom Kolbenraum 6 aus über die Bohrung 17', die Rückschlagventile 18, die Bohrung 17 und die Bohrung 13 - nur sehr langsam erfolgt, währenddem der Gegendruck auf das Arretierglied 10 - vom Kolbenraum 9 aus - im Verlauf der Aufwärtsbewegung des Kolbens 4 nur unwesentlich abnimmt. Entsprechend diesem Verhalten ist die Anordnung so ausgelegt, dass das Eingreifen des Arretiergliedes 10 erst bei stillstehendem Kolben 4 zustande kommt, wodurch hier ebenfalls die Wirksamkeit gefördert und der Verschleiss vermieden wird.To reopen the valve 30, the coil 22 is energized, whereby the solenoid valve 20 closes; the reverse process then takes place compared to that described above. It is important that the pressure increase in the piston chamber 6 takes place very slowly because the volume of the piston chamber 6 increases continuously during the upward movement of the piston 4, so that the pressure build-up in this chamber with the aid of the pressure medium supply from the valve chamber 33 via the bore 37, to to stop the rear seat seal 36 on the counter surface, is slowed down. In contrast, pressure medium must be expelled from the piston chamber 9 into the atmosphere via the throttle 49, so that the pressure in the chamber 9 decreases only slightly during the piston movement until it stops. It follows that the pressure increase in the pressure chamber 12 - from the piston chamber 6 via the bore 17 ' , the check valves 18, the bore 17 and the bore 13 - takes place only very slowly, while the counterpressure on the locking member 10 - from the piston chamber 9 - decreases only insignificantly in the course of the upward movement of the piston 4. In accordance with this behavior, the arrangement is designed such that the locking member 10 only engages when the piston 4 is at a standstill, which also promotes effectiveness and prevents wear.

Die besonderen Vorteile der Erfindung treten in der beschriebenen Ausführungsform besonders deutlich in Erscheinung, wenn das Ventil 30 bei sehr kleinem Druck des Druckmediums, eventuell kleiner als 1 bar, offengehalten werden muss, was z.B. im Betrieb von Dampfturbinen üblich ist. In solch einem Fall sinkt der Druck im Gehäuse 30 des Ventils. Über die Bohrungen 37, 50 und 54 sinkt auch der Druck im Kolbenraum 6, im Zylinderraum 53 und in der Kammer 51. Vom Eigengewicht getrieben, verschiebt sich der Kolben 52, sobald der Druck im Zylinderraum 53 ihn nicht mehr tragen kann, und verbindet die Bohrung 50 mit der Bohrung 50" und 50' sowie 48. Durch diese Verbindung sinkt auch im Kolbenraum 9 der Druck. Es herrscht also überall der gleiche, tiefe Druck, und es wirken weder auf den Kolben 4 noch auf den Verschlussteil 40, irgendwelche Druckdifferenzen, so dass das bewegliche System 2 das Bestreben hat, durch sein Eigengewicht in Schliessstellung zu gehen. Dies muss aber - entsprechend der Aufgabenstellung - verhindert werden, was von dem Arretierglied 10 folgendermassen bewerkstelligt wird.The particular advantages of the invention appear particularly clearly in the described embodiment if the valve 30 has to be kept open at a very low pressure of the pressure medium, possibly less than 1 bar, which e.g. is common in the operation of steam turbines. In such a case, the pressure in the valve housing 30 drops. Via the bores 37, 50 and 54, the pressure in the piston chamber 6, in the cylinder chamber 53 and in the chamber 51 also drops. Driven by its own weight, the piston 52 moves as soon as the pressure in the cylinder chamber 53 can no longer support it and connects it Bore 50 with the bore 50 "and 50 'and 48. Through this connection, the pressure also drops in the piston chamber 9. The same low pressure prevails everywhere, and there are no pressure differences on either the piston 4 or the closure part 40 , so that the movable system 2 tends to move into its closed position due to its own weight, but this must be prevented according to the task, which is accomplished by the locking member 10 as follows.

Die Spule 22 liegt über die Steuersignalleitung 29 an Spannung. Das Magnetventil 20 bleibt infolgedessen geschlossen. Die Rückschlagventile 18 verhindern ein Abfallen des Druckes in den Bohrungen 17, 19 und 13 zwischen dem Druckraum 12 und dem Magnetventil 20 auf das Druckniveau im Kolbenraum 6, so dass in dem genannten Bereich der vom Dampferzeuger 16 bestimmte Druck herrscht. Infolgedessen bleibt das Arretierglied 10 wunschgemäss so lange in Arretierstellung, wie das Magnetventil 20 unter Spannung steht. Dadurch wird das Schliessen des Ventils 30 verhindert. Wie schon oben erwähnt, bleibt die Haltewirkung des Arretiergliedes 10 auch bei einem Ausfall des Dampferzeugers 16 dank der Wirkung der Rückschlagventile 15 und 18 noch eine gewisse Zeit bestehen.The coil 22 lies over the control signal line 29 in tension. As a result, the solenoid valve 20 remains closed. The check valves 18 prevent the pressure in the bores 17, 19 and 13 between the pressure chamber 12 and the solenoid valve 20 from dropping to the pressure level in the piston chamber 6, so that the pressure determined by the steam generator 16 prevails in the region mentioned. As a result, the locking member 10 remains in the locking position as long as the solenoid valve 20 is under tension. This prevents the valve 30 from closing. As already mentioned above, the holding effect of the locking member 10 remains for a certain time even in the event of a failure of the steam generator 16 thanks to the action of the check valves 15 and 18.

Wird - abweichend vom beschriebenen Beispiel nach Fig. 1 - das Arretierglied 10 im Druckbereich des Kolbenraumes 6 angeordnet, so ist es möglich, das Arretierglied 10 in Abhängigkeit der vorhandenen Drücke so zu bemessen, dass es erst bei niedrigem Druck im Kolbenraum 6 zum Eingriff kommt, wodurch der Verschleiss vermindert wird.If - in contrast to the described example according to FIG. 1 - the locking member 10 is arranged in the pressure area of the piston chamber 6, it is possible to dimension the locking member 10 in dependence on the existing pressures in such a way that it only comes into engagement at low pressure in the piston chamber 6 , which reduces wear.

Bei der Anordnung nach Fig. 1 ist es möglich, das Arretierglied 10 derart einzubauen, dass die Sicherheit der Stellmotoranordnung weitgehend von äusseren Einwirkungen frei bleibt. Diese können darin bestehen, dass die externe Steuersignalleitung 29 oder das Magnetventil 20 zerstört wird oder dass sogar im Zusammenhang mit einer Zerstörung des Magnetventils 20 die Ventilspindel 24 weggerissen wird. In jedem Fall fährt der Stellmotor und damit auch der Verschlussteil 40, in die Sicherheitsstellung.In the arrangement according to FIG. 1, it is possible to install the locking member 10 in such a way that the safety of the servomotor arrangement remains largely free of external influences. These can consist in that the external control signal line 29 or the solenoid valve 20 is destroyed or that the valve spindle 24 is torn away even in connection with a destruction of the solenoid valve 20. In any case, the servomotor and thus also the closure part 40 move into the safety position.

Im Beispiel nach Fig. 1 sind zwei Druckmittelquellen gezeigt. Es ist jedoch möglich, mehr als zwei Druckmittelquellen und/oder mehrere Druckmittelsenken an die Stellmotoranordnung anzuschliessen, wobei Auswahlschaltungen vorgesehen sein können, so dass jeweils die Druckmittelquelle mit dem höchsten Druck und die Druckmittelsenke mit dem tiefsten Druck zur Wirkung kommen.In the example according to FIG. 1, two pressure medium sources are shown. However, it is possible to connect more than two pressure medium sources and / or several pressure medium sinks to the servomotor arrangement, it being possible for selection circuits to be provided so that the pressure medium source with the highest pressure and the pressure medium sink with the lowest pressure come into effect.

In Fig. 2 ist das Arretierglied 10 nach Fig. 1 in Form einer Membran in vergrössertem Massstab gezeigt. Die Membran 410 weist auf der in Fig. 2 rechten Seite die Stirnfläche 11 auf, die dem Druckmedium im Druckraum 12 ausgesetzt ist. Die andere Seite der Membran 410 verläuft parallel zu einer Bremsfläche 101 am Fortsatz 5 des beweglichen Systems 2, wobei ein schmaler Spalt diese beiden Flächen voneinander trennt, wenn die Membran nicht in Arretierstellung ist. Die Membran 410 besteht aus einem flexiblen Material, z.B. einem Federstahlblech, und ist an einem feststehenden Teil der Stellmotoranordnung 1 dicht angeschweisst, aber so, dass ihre Flexibilität und die damit zusammenhängende Beweglichkeit noch genügend erhalten bleiben. Die Bremsfläche 101 ist auf einem Einsatz 102 vorhanden, der am beweglichen System 2 der Stellmotoranordnung befestigt ist und z.B. aus einem versilberten oder vernickelten Austenitstahlblech besteht, das gegenüber der Membran 410 einen hohen Reibungskoeffizienten aufweist. Wie im Beispiel nach Fig. 1 gelangt hier das Druckmittel über die Bohrung 13 in den Druckraum 12.In Fig. 2 the locking member 10 is shown in FIG. 1 in the form of a membrane on an enlarged scale. The membrane 410 has on the right side in FIG. 2 the end face 11 which is exposed to the pressure medium in the pressure chamber 12. The other side of the membrane 410 runs parallel to a braking surface 101 on the extension 5 of the movable system 2, a narrow gap separating these two surfaces from one another when the membrane is not in the locking position. The membrane 410 is made of a flexible material, e.g. a spring steel sheet, and is tightly welded to a fixed part of the servomotor arrangement 1, but in such a way that its flexibility and the associated mobility are still sufficiently preserved. The braking surface 101 is provided on an insert 102 which is attached to the movable system 2 of the servomotor arrangement and e.g. consists of a silver-plated or nickel-plated austenitic steel sheet, which has a high coefficient of friction compared to the membrane 410. As in the example according to FIG. 1, the pressure medium reaches the pressure chamber 12 via the bore 13.

Im Betrieb wird die Membran 410 vom Druckmittel im Druckraum 12 beaufschlagt und verformt sich dabei, so dass sie gegen die Bremsfläche 101 gedrückt wird und durch Reibung das bewegliche System 2 festhält. Wird nun, z.B. durch Umstellen eines nicht gezeigten Dreiwegventils, die Verbindung zur Druckmittelquelle unterbrochen und auf eine Druckmittelsenke umgeschaltet, sinkt der Druck im Druckraum 12, und die Membran 410 wird entspannt. Durch ihre eigene Elastizität nimmt sie nun wieder ihre ursprüngliche Form parallel zur Bremsfläche 101 ein, so dass das bewegliche System 2 freigegeben wird.In operation, the diaphragm 410 is acted upon by the pressure medium in the pressure chamber 12 and deforms so that it is pressed against the braking surface 101 and holds the movable system 2 in place by friction. Now, e.g. by changing over a three-way valve (not shown), the connection to the pressure medium source is interrupted and switched to a pressure medium sink, the pressure in the pressure chamber 12 drops and the membrane 410 is relaxed. Due to its own elasticity, it now resumes its original shape parallel to the braking surface 101, so that the movable system 2 is released.

Es können sowohl eine einzige Membran als auch mehrere Membranen 410 um den Fortsatz 5 herum angeordnet sein. Es ist auch möglich, eine einzige, den Fortsatz 5 umschliessende zylindrische Membran zu verwenden, die in der Arretierstellung den Fortsatz 5 am ganzen Umfang gleichmässig belastet.Both a single membrane and a plurality of membranes 410 can be arranged around the extension 5. It is also possible to use a single cylindrical membrane enclosing the extension 5, which in the locking position loads the extension 5 evenly over the entire circumference.

Das Beispiel gemäss Fig. 3 unterscheidet sich von dem nach Fig. 2 dadurch, dass die Membran 410 eine Wölbung 103 aufweist, die in der Arretierstellung in einer entsprechenden Vertiefung 104 im Fortsatz 5 anliegt. Durch das Anliegen der Wölbung 103 in der Vertiefung 104 entstehen Kräfte, die zusätzlich zur Reibung wirken, sodass ein kleinerer Druck als im Beispiel nach Fig. 2 erforderlich ist, um bei gleichen Abmessungen des Arretiergliedes das bewegliche System 2 zu arretieren.The example according to FIG. 3 differs from that according to FIG. 2 in that the membrane 410 has a curvature 103 which, in the locking position, bears in a corresponding depression 104 in the extension 5. Due to the fact that the curvature 103 rests in the depression 104, forces arise which act in addition to the friction, so that a smaller pressure than in the example according to FIG. 2 is required in order to lock the movable system 2 with the same dimensions of the locking member.

Gemäss Fig. 4 ist das Arretierglied als Kölbchen 110 ausgebildet. Das Kölbchen ist auf seiner Stirnfläche 11 an einem Wellrohr 111 dicht angeschlossen, so dass es koaxial mit dem Wellrohr 111 in einer Bohrung im feststehenden Teil 67 der Stellmotoranordnung 1 verschiebbar geführt ist. Um ein Festsitzen des Kölbchens 110 zu vermeiden, erleichtert eine Lagerbüchse 112 das Gleiten, und mehrere Ringnuten 113 im Kölbchen sorgen für den peripheren Druckausgleich. Ein Bund 114 des Kölbchens 110 begrenzt den Hub des Kölbchens durch Anschlagen an einen Ringsitz 115 am feststehenden Teil 67.According to FIG. 4, the locking member is designed as a small cup 110. The little end of the cologne is tightly connected to a corrugated tube 111, so that it is slidably guided coaxially with the corrugated tube 111 in a bore in the fixed part 67 of the servomotor arrangement 1. In order to prevent the small cup 110 from becoming stuck, a bearing bush 112 facilitates sliding, and a plurality of ring grooves 113 in the small cup ensure peripheral pressure compensation. A collar 114 of Cologne 110 limits the stroke of Cologne by striking ring seat 115 on fixed part 67.

Das bewegliche System 2 weist eine Vertiefung 104 auf, die mit ihrem in Fig. 4 oberen Abschnitt eine Schulter 105 bildet, an der das Kölbchen 110 in seiner Arretierlage mit einer Auflagefläche 116 anliegt. Ein Deckel 117 ist durch Schrauben 118 am feststehenden Teil 67 befestigt, wobei ein O-Ring 119 diese Verbindung dichtet. Das Wellrohr 111 ist mit dem Deckel 117 dicht verbunden und umschliesst den Druckraum 12. Dieser Raum ist über die Bohrung 13 im Dekkel 117 und ein das Abschlussorgan bildendes Dreiwegventil 61 mit einer nicht dargestellten Druckmittelquelle (Stutzen 60) und einer ebenfalls nicht dargestellten Druckmittelsenke (Stutzen 62) verbunden.The movable system 2 has a depression 104, which, with its upper section in FIG. 4, forms a shoulder 105, against which the little cap 110 rests in its locking position with a contact surface 116. A cover 117 is fastened to the fixed part 67 by screws 118, an O-ring 119 sealing this connection. The corrugated tube 111 is tightly connected to the cover 117 and encloses the pressure chamber 12. This space is via the bore 13 in the cover 117 and a three-way valve 61 forming the closing element with a pressure medium source (connector 60) not shown and a pressure medium sink (connector) also not shown 62) connected.

In Fig. 4 ist das Kölbchen 110 in der Haltelage gezeigt, wobei das Dreiwegventil 61 die gezeichnete Stellung einnimmt, in der der Druckraum 12 mit der Druckmittelquelle in Verbindung steht. Dabei wird der Bund 114 auf den Ringsitz 115 gepresst. Dreht man nun das Dreiwegventil 61 um 90° gegen den Uhrzeigersinn, so wird die Verbindung mit der Druckmittelquelle unterbrochen und über den Stutzen 62 diejenige mit der Druckmittelsenke hergestellt. Dadurch fällt der Druck im Druckraum 12 ab, und es verringert sich die auf das Kölbchen 110 wirkende Kraft, die dem Produkt aus dem Druck im Druckraum 12 mal der Grösse der Stirnfläche 11 entspricht. Es überwiegt jetzt die Kraft, die das Kölbchen 110 von der Vertiefung 104 wegschieben will, so dass das Kölbchen 110 in Richtung zum Druckraum 12 gleitet und dabei das Wellrohr 111 zusammendrückt und das bewegliche System 2 freigibt.4 shows the little cap 110 in the holding position, the three-way valve 61 assuming the position shown in which the pressure chamber 12 is connected to the pressure medium source. The collar 114 is pressed onto the ring seat 115. If the three-way valve 61 is now rotated counterclockwise by 90 °, the connection to the pressure medium source is interrupted and that to the pressure medium sink is established via the connection piece 62. As a result, the pressure in the pressure chamber 12 drops and the force acting on the piston 110, which corresponds to the product of the pressure in the pressure chamber 12 times the size of the end face 11, is reduced. The force now prevails that the little boy 110 wants to push away from the depression 104, so that the little boy 110 slides in the direction of the pressure chamber 12 and thereby compresses the corrugated tube 111 and releases the movable system 2.

Bei der Bemessung des Kölbchens 110 müssen die Druckdifferenzen, die Reibung an den Gleitflächen und die vom beweglichen System 2 auf die Auflagefläche 116 ausgeübte Kraft berücksichtigt werden. Die auf die Auflagefläche 116 wirkende Kraftkomponente, die das Verschieben des Kölbchens 110 beeinflusst, hängt vom Winkel a zwischen der Bewegungsrichtung des Systems 2 und der Auflagefläche 116 ab.When dimensioning the small basket 110, the pressure differences, the friction on the sliding surfaces and the force exerted by the movable system 2 on the bearing surface 116 must be taken into account. The force component which acts on the support surface 116 and which influences the displacement of the small basket 110 depends on the angle α between the direction of movement of the system 2 and the support surface 116.

Bei dem Arretierglied in Form eines Kölbchens 110 gemäss Fig. 5 sind anstelle des Wellrohrs 111 zwei Dichtflächen 106 und 107 am Bund 114 vorgesehen, die mit entsprechenden Sitzen 46 bzw. 46' zusammenwirken. In der Arretierstellung des Kölbchens 110 wird die Dichtfläche 106 auf den Sitz 46 gepresst, was verhindert, dass Druckmedium den Spalt zwischen dem Kölbchen 110 und der Lagerbüchse 112 durchfliesst, wodurch Schäden verursacht werden könnten. Ist dagegen das Kölbchen 110 in der Stellung, in der das bewegliche System 2 frei ist, und wirkt dabei eine Druckdifferenz auf das Kölbchen in Richtung zum Druckraum 12, so wird die Dichtfläche 107 auf den Sitz 46' gepresst, und es kann kein fremdes Medium in die Bohrung 13 eindringen. Eine entsprechende Dimensionierung der wirksamen Flächen am Kölbchen 110 in Abhängigkeit der vorhandenen Drücke ist dabei vorzunehmen.5, instead of the corrugated tube 111, two sealing surfaces 106 and 107 are provided on the collar 114, which cooperate with corresponding seats 46 and 46 ', respectively. In the locking position of the small basket 110, the sealing surface 106 is pressed onto the seat 46, which prevents pressure medium from flowing through the gap between the small basket 110 and the bearing bush 112, which could cause damage. If, on the other hand, the basket 110 is in the position in which the movable system 2 is free, and a pressure difference acts on the basket in the direction of the pressure chamber 12, the sealing surface 107 is pressed onto the seat 46 'and no foreign medium can exist penetrate into the bore 13. Appropriate dimensioning of the effective areas on the small cap 110 depending on the pressures present is to be carried out.

Im übrigen wirkt das Kölbchen nach Fig. 5 gleich wie dasjenige nach Fig. 4.5 acts the same as that of FIG. 4.

Gemäss Fig. 6 hat das Arretierglied 210 Kugelform, die zum Teil den Druckraum 12 begrenzt und zum Teil - bei Arretierstellung - in der Vertiefung 104 des beweglichen Systems 2 liegt. Diese Ausführungsform ist besonders einfach und preisgünstig.6, the locking member 210 has a spherical shape, which partly delimits the pressure chamber 12 and partly - in the locking position - lies in the recess 104 of the movable system 2. This embodiment is particularly simple and inexpensive.

Bei dem Ausführungsbeispiel nach Fig. 7 sind zwischen dem Kölbchen 310 und dem beweglichen System 2 kugelförmige Zwischenglieder 70 angeordnet. Das einen Teil eines Arretiergliedes bildende Kölbchen 310 ist hier parallel zur Verschieberichtung des beweglichen Systems 2 verschiebbar und weist als Hubbegrenzung zwei Dichtsitze 72 und 73 auf, die mit entsprechenden Gegenflächen am feststehenden Teil 67 zusammenwirken. Der Dichtsitz 72 befindet sich an der Stirnfläche 11 des Kölbchens 310, während der Dichtsitz 73 auf der anderen Stirnseite des Kölbchens liegt. In der zylindrischen Führungsfläche des Kölbchens 310 sind Kolbenringe 74 untergebracht, die auf bekannte Art dichten. Zwischen der in Fig. 7 unteren Stirnseite des Kölbchens 310 und dem beweglichen System 2 sind als Zwischenglieder mehrere Kugeln 70 kranzförmig angeordnet, die sich auf einer geneigten Stützfläche 68 des feststehenden Teils 67 quer zur Verschieberichtung des beweglichen Systems 2 bewegen können. Die Kugeln 70 greifen bei Arretierstellung in eine Ringnut 108 am beweglichen System 2 ein. Die Stützfläche 68, die dem Kölbchen 310 gegenübersteht, weist eine Neigung β gegenüber der Verschieberichtung des Systems 2 auf. Die Grösse der Neigung β hängt vom Druck des Druckmittels und von der Lage der Angriffsstelle 75 ab, mit der sich das bewegliche System 2 auf den Kugeln 70 bei vollem Eingriff abstützt.In the exemplary embodiment according to FIG. 7, two spherical intermediate elements 70 are arranged between the small basket 310 and the movable system. The claw 310 forming part of a locking member can be displaced parallel to the direction of displacement of the movable system 2 and has two sealing seats 72 and 73 as a stroke limitation, which cooperate with corresponding mating surfaces on the fixed part 67. The sealing seat 72 is located on the end face 11 of the Cologne 310, while the sealing seat 73 is located on the other end of the Cologne. Piston rings 74, which seal in a known manner, are accommodated in the cylindrical guide surface of the small piston 310. A plurality of balls 70 are arranged as intermediate elements between the lower end face of the cilette 310 in FIG. 7 and the movable system 2, which balls can move on an inclined support surface 68 of the fixed part 67 transversely to the direction of displacement of the movable system 2. When locked, the balls 70 engage in an annular groove 108 on the movable system 2. The support surface 68, which is opposite the small basket 310, has an inclination β with respect to the direction of displacement of the system 2. The magnitude of the inclination β depends on the pressure of the pressure medium and on the position of the point of attack 75 with which the movable system 2 is supported on the balls 70 when fully engaged.

Die Stützfläche 68 weist einen das bewegliche System 2 umgebenden Rand 69 auf, der verhindert, dass die Kugeln 70 bei ausgefahrenem System 2 herausfallen. Ähnlich wie in Fig. 4 gezeigt, gehören zur Ausführungsform nach Fig. 7 ein Abschlussorgan, eine Druckmittelquelle und eine Druckmittelsenke.The support surface 68 has an edge 69 which surrounds the movable system 2 and which prevents the balls 70 from falling out when the system 2 is extended. Similar to FIG. 4, the embodiment according to FIG. 7 includes a closing element, a pressure medium source and a pressure medium sink.

Ebenso gehört dazu ein nicht gezeigtes Dichtungselement zwischen dem Deckel 66 und dem feststehenden Teil 67. Das Druckmittel gelangt durch die Bohrung 13 im Deckel 66 in den Druckraum 12.This also includes a sealing element (not shown) between the cover 66 and the fixed part 67. The pressure medium passes through the bore 13 in the cover 66 into the pressure chamber 12.

Das bewegliche System 2 belastet die Kugeln 70 mittels der Schulter 105 in der Ringnut 108, und zwar in Richtung vom Druckraum 12 auf die Kugeln 70 zu. Die Kugeln 70 nehmen die Belastung auf der Angriffsstelle 75 auf und übertragen einen Teil davon auf die Stützfläche 68. Diese Fläche zerlegt die auf sie ausgeübte Kraft in zwei Komponenten: Eine zur Stützfläche 68 senkrechte Kraftkomponente, die als Ursache einer Reibungskraft wirksam ist, und eine zur Stützfläche 68 parallele Kraftkomponente, die - der Reibungskraft entgegen - die Kugeln 70 vom beweglichen System 2 zu entfernen versucht. Während der Arretierphase wird eine Bewegung der Kugeln 70 durch das Kölbchen 310 verhindert, wobei dieses vom Druckmittel festgehalten wird, das im Druckraum 12 auf die Stirnfläche 11 wirkt. In dieser Lage liegt das Kölbchen 310 mittels dem Dichtsitz 73 dichtend auf der zugehörigen Gegenfläche, wobei ein Entweichen von Druckmittel vermieden wird. Wie im Fall entsprechend Fig. 4 wird die Arretierung dadurch gelöst, dass durch Verstellen des nicht gezeichneten Abschlussorgans der Druckraum 12 mit der Druckmittelsenke verbunden wird, wodurch das Kölbchen vom Druck entlastet und durch die Kugeln 70 aufwärtsbewegt wird. Falls der Druck in der Umgebung der Kugeln 70 denjenigen im Druckraum 12 übersteigt, verhindern der Dichtsitz 72 und seine Gegenfläche einen Druckmittelabfluss über den Druckraum 12 in die Bohrung 13.The movable system 2 loads the balls 70 by means of the shoulder 105 in the annular groove 108, specifically in the direction from the pressure chamber 12 towards the balls 70. The balls 70 absorb the load on the point of attack 75 and transfer a part thereof to the support surface 68. This surface divides the force exerted on them into two components: a force component perpendicular to the support surface 68, which acts as the cause of a frictional force, and one force component parallel to the support surface 68, which — contrary to the frictional force — tries to remove the balls 70 from the movable system 2. During the locking phase, the balls 70 are prevented from moving by the small piston 310, which is held in place by the pressure medium which acts on the end face 11 in the pressure chamber 12. In this position, the small piece 310 lies in a sealing manner on the associated counter surface by means of the sealing seat 73, wherein pressure medium is prevented from escaping. As in the case according to FIG. 4, the locking is released by connecting the pressure chamber 12 to the pressure medium sink by adjusting the closing element (not shown), as a result of which the cologne is relieved of pressure and moved upwards by the balls 70. If the pressure in the vicinity of the balls 70 exceeds that in the pressure chamber 12, the sealing seat 72 and its counter surface prevent pressure medium from flowing out via the pressure chamber 12 into the bore 13.

Im Ausführungsbeispiel nach Fig. 7 werden Kugeln 70 als Zwischenglieder gezeigt. Es können jedoch anders geformte Teile dazu verwendet werden, die durch Kraftanwendung an einer bestimmten Stelle in eine voraussehbare Richtung7 balls 70 are shown as intermediate members. However, other shaped parts can be used to do this by applying force at a particular location in a predictable direction

ausgleiten, wie das z.B. bei Klemmgesperren der Fall ist. Es ist auch die Verwendung von Winkelhebeln denkbar. Bei den Ausführungsformen mit Kölbchen als Arretierglied kann der Kontakt zwischen dem Kölbchen und der Schulter punkt-, linien- oder flächenförmig ausgebildet sein, je nach Gestaltung der Kontaktflächen. Dies erlaubt, die Grösse der Flächenpressung an dieser Stelle innerhalb weiter Grenzen zu variieren, entsprechend den vorhandenen Drücken, Materialien und Reibungskoeffizienten.slip out like that e.g. is the case with locking mechanisms. The use of angle levers is also conceivable. In the embodiments with cobs as locking elements, the contact between the cobs and the shoulder can be point-shaped, linear or flat, depending on the design of the contact surfaces. This makes it possible to vary the size of the surface pressure at this point within wide limits, depending on the pressures, materials and coefficients of friction available.

In allen Ausführungsformen mit einem Kölbchen wird die Rückstellkraft, die das Kölbchen aus der Eingriffsstellung zurückschiebt, durch das bewegliche System 2 selbst hervorgebracht, das über die Schulter 105 auf die schräge Auflagefläche 116 bzw. die Stützfläche 68 wirkt. Es ist aber möglich, das Kölbchen mittels mindestens einer Feder, z.B. aus Shtal, zurückzuverschieben.In all embodiments with a little cup, the restoring force which pushes the little boy back out of the engagement position is brought about by the movable system 2 itself, which acts on the oblique contact surface 116 or the supporting surface 68 via the shoulder 105. However, it is possible to use at least one spring, e.g. from Shtal, move back.

Es ist auch denkbar, das Kölbchen nicht senkrecht, sondern schräg zur Verschieberichtung des beweglichen Systems 2 verschiebbar anzuordnen.It is also conceivable to arrange the cupper so that it cannot be displaced vertically but at an angle to the direction of movement of the movable system 2.

Die Kompaktheit der verschiedenen Ausführungsformen der Erfindung und die Einfachheit ihrer Betätigungssysteme erlauben den Einbau von mehreren Arretiergliedern, die gleichzeitig oder unabhängig voneinander eingreifen können. Im ersten Fall erreicht man eine zusätzliche Sicherheit durch Redundanz, eine bessere Verteilung der Kräfte und eine Verminderung der Flächenpressung. Im zweiten Fall wird die Durchführung von Reparaturen oder Revisionen ohne Beeinträchtigung der Sicherheit der Anordnung ermöglicht, da ein Teil der Arretierglieder stets in Betrieb bleiben kann.The compactness of the various embodiments of the invention and the simplicity of their actuation systems allow the installation of several locking members that can intervene simultaneously or independently of one another. In the first case, additional security is achieved through redundancy, a better distribution of forces and a reduction in surface pressure. In the second case, repairs or revisions can be carried out without affecting the safety of the arrangement, since some of the locking elements can always remain in operation.

Es ist ebenfalls möglich, das bewegliche System 2 - ausser in den Endstellungen - auch in mindestens einer Zwischenstellung zu arretieren. Dies kann sowohl durch eine Schulterebene und mehrere, gegenüber verschiedenen Hubstellungen des beweglichen Systems 2 angeordneten Arretiergliedern 10 als auch durch mehrere Schulterebenen gegenüber einer einzigen Ebene der Anordnung, in der mindestens ein Arretierglied angebracht ist, erreicht werden.It is also possible to lock the movable system 2 - in addition to the end positions - in at least one intermediate position. This can be achieved both by means of a shoulder plane and a plurality of locking members 10 arranged in relation to different stroke positions of the movable system 2, and also by a plurality of shoulder levels in relation to a single level of the arrangement in which at least one locking member is attached.

Claims (8)

1. A pressure-medium-operated servomotor arrangement (1) having a piston (4) sliding in a cylinder (3) which communicates with a valve body (30) extending around a valve chamber (33), the piston (4) being connected to a valve lid (40) movable in the valve body (30) between a normally open position and a closed safety position, the piston (4) subdividing the cylinder (3) into two cylinder chambers (6, 9), one such chamber (6) being near the lid (4) while the other such chamber (9) is remote therefrom, each cylinder chamber (6, 9) communicating by way of its own connecting line (50, 50'; 37) with the valve chamber (33) as pressure medium source and by way of another independent connecting line (48; 17', 19) with a pressure medium sink, a first control valve (52) being disposed in the connecting line (50, 50') via which the valve chamber (33) communicates with the cylinder chamber (9) remote from the valve lid (40) while a second control valve (20) is disposed in the connecting line (17', 19) via which the cylinder chamber (6) near the valve chamber (33) communicates with the pressure medium sink, whereas a restrictor (49, 38) is disposed in each of the other connecting lines, the second control valve (20) being connected to an external control line (29) and the first control valve (52), which is operable by pressure medium, communicates by way of an internal control line (54) with the cylinder chamber (6) near the valve lid (40), characterised in that at least one retaining member (10) movable transversely to the direction of piston movement is provided to retain the piston and is in operative engagement with at least one end face (11) bounding a pressure chamber (12); the same communicates both with one other pressure medium source (16) independent of the pressure medium source formed by the valve chamber (33) and also, at a place between the cylinder chamber (6) near the lid (4) and the second control valve (20), with the connecting line (17', 19) extending to the pressure medium sink; and at least one check valve (15) is disposed between the pressure chamber (12) and the other pressure medium source (16) and prevents a pressure drop in the pressure chamber (12) when the second control valve (20) is in a position in which the retaining member (10) is retaining the piston (4).
2. An arrangement according to claim 1, characterised in that the retaining member (10) is so devised that even when the highest possible pressure of the other pressure medium source is acting on the end face (11), the piston (4) overcomes the retaining force of the retaining member (10) in response to a predetermined axial critical loading of the piston being exceeded.
3. An arrangement according to claim 1 or 2, characterised in that the retaining member is a diaphragm (10), one side of which is operative as the end face (11) bounding the pressure chamber (12) while the other side engages as a brake member with a braking surface, either the diaphragm being disposed on a stationary part (35) of the servomotor arrangement and the braking surface being disposed on the piston (4) or the diaphragm being disposed on the piston (4) and the braking surface being disposed on a stationary part of the servomotor arrangement.
4. An arrangement according to claim 1 or 2, characterised in that the retaining member comprises a plunger (110), one end face of which is the end face bounding the pressure chamber.
5. An arrangement according to claim 4, characterised in that the plunger (110) is sealingly connected to the servomotor arrangement by way of a corrugated tube (111).
6. An arrangement according to claim 4, characterised in that the plunger forms a sealing set with the servomotor arrangement at least in one of its end positions.
7. An arrangement according to any of claims 4-6, characterised in that the operative engagement between the plunger (310) and the piston (4) is by way of at least one intermediate member (70) which bears movingly on a bearing or support surface (68) of the servomotor arrangement.
8. An arrangement according to claim 7, characterised in that the intermediate element (70) is a rolling member and the bearing or support surface (68) makes an angle of other than 0° with the direction of movement of the piston (4).
EP83100503A 1982-12-15 1983-01-21 Fluid-pressure actuated activating device with locking member Expired EP0111617B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH7288/82 1982-12-15
CH7288/82A CH659111A5 (en) 1982-12-15 1982-12-15 PRESSURE-ACTUATED ACTUATOR ARRANGEMENT WITH LOCKING MEMBER.

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EP0111617A1 EP0111617A1 (en) 1984-06-27
EP0111617B1 true EP0111617B1 (en) 1987-12-09

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EP (1) EP0111617B1 (en)
JP (1) JPS59131080A (en)
CA (1) CA1221283A (en)
CH (1) CH659111A5 (en)
DE (1) DE3374891D1 (en)
ES (1) ES527633A0 (en)

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Also Published As

Publication number Publication date
CH659111A5 (en) 1986-12-31
ES8501071A1 (en) 1984-11-16
ES527633A0 (en) 1984-11-16
EP0111617A1 (en) 1984-06-27
DE3374891D1 (en) 1988-01-21
US4700925A (en) 1987-10-20
CA1221283A (en) 1987-05-05
JPS59131080A (en) 1984-07-27

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