EP3475583B1 - Hydropneumatic piston accumulator - Google Patents

Hydropneumatic piston accumulator Download PDF

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Publication number
EP3475583B1
EP3475583B1 EP17717082.6A EP17717082A EP3475583B1 EP 3475583 B1 EP3475583 B1 EP 3475583B1 EP 17717082 A EP17717082 A EP 17717082A EP 3475583 B1 EP3475583 B1 EP 3475583B1
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EP
European Patent Office
Prior art keywords
piston
housing cover
housing
measuring tube
tube
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Application number
EP17717082.6A
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German (de)
French (fr)
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EP3475583C0 (en
EP3475583A1 (en
Inventor
Horst Mannebach
Peter Kloft
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Hydac Technology GmbH
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Hydac Technology GmbH
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Publication date
Priority claimed from DE102016007824.3A external-priority patent/DE102016007824A1/en
Priority claimed from DE102016007798.0A external-priority patent/DE102016007798A1/en
Application filed by Hydac Technology GmbH filed Critical Hydac Technology GmbH
Priority to EP23162104.6A priority Critical patent/EP4230874A3/en
Publication of EP3475583A1 publication Critical patent/EP3475583A1/en
Application granted granted Critical
Publication of EP3475583C0 publication Critical patent/EP3475583C0/en
Publication of EP3475583B1 publication Critical patent/EP3475583B1/en
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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
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/04—Accumulators
    • F15B1/08—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor
    • F15B1/24—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor with rigid separating means, e.g. pistons
    • 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
    • F15B2201/00—Accumulators
    • F15B2201/30—Accumulator separating means
    • F15B2201/31—Accumulator separating means having rigid separating means, e.g. pistons
    • 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
    • F15B2201/00—Accumulators
    • F15B2201/50—Monitoring, detection and testing means for accumulators
    • F15B2201/515—Position detection for separating means

Definitions

  • the invention relates to a hydropneumatic piston accumulator having the features in the preamble of claim 1.
  • Hydraulic accumulators such as hydropneumatic piston accumulators
  • hydropneumatic piston accumulators are used in hydraulic systems to take up certain volumes of pressurized liquid, such as hydraulic oil, and return it to the system when required.
  • pressurized liquid such as hydraulic oil
  • the position of the piston changes so that the accumulator absorbs hydraulic oil when the pressure rises, with the gas in the other Working space is compressed.
  • the compressed gas expands, pushing stored hydraulic oil back into the hydraulic circuit.
  • the resulting changes in the volumes of the working chambers during operation result in a corresponding axial movement of the piston.
  • the pressure prevailing in the working chamber of the working gas is adapted to the pressure level in the oil-side working chamber, so that the piston is located at suitable points within the accumulator housing and thereby can carry out the working movements between piston end positions in the accumulator housing. Determining the position that the piston assumes at a given fluid pressure in the oil-side working chamber also enables the level of filling pressure of the working gas in the associated working chamber to be determined and thus allows the piston accumulator to be monitored for proper functionality.
  • the JP H07 269503 discloses a hydropneumatic piston accumulator with an accumulator housing which has a cylinder tube defining a longitudinal axis, which is closed at both ends by a respective housing cover and in which a piston can be moved longitudinally, which in the housing has a working space for a compressible medium, such as a working gas, from a Working space for an incompressible medium, such as hydraulic oil, separates, and with a non-contact position of the piston in the housing determining distance measuring device, which has a non-magnetic measuring tube, which extends through a passage formed in the piston along the longitudinal axis from one housing cover to the other housing cover and is sealed against the interior of the housing.
  • the JP S62 97307 U describes a working cylinder with a measuring tube, in which a position sensor is slidably guided, which follows the piston movements in the measuring tube by a magnetic force acting between it and a piston of the working cylinder, with a transmitter/receiver of a displacement measuring device being arranged on a housing cover of the working cylinder, which is emits measuring radiation passing through an open end of the measuring tube to the position transmitter and receives radiation reflected from it.
  • the DE 71 03 342 U discloses another hydraulic accumulator and the DE 10 2004 057 769 A1 describes another working cylinder.
  • the object of the invention is to provide a hydropneumatic piston accumulator of the type mentioned at the outset, the travel measuring device of which enables the position of the piston to be determined in a particularly simple and advantageous manner.
  • a position sensor serving for the measuring process which is slidably guided in the measuring tube, follows the movements of the piston under the influence of a magnetic force acting between the piston and position sensor in the measuring tube.
  • a transmitter/receiver of the distance measuring device located on a housing cover transmits a measurement radiation through the relevant open end of the measuring tube to the position transmitter and receives radiation reflected from it.
  • a magnetic ring is provided which is fixed to the passage of the piston and surrounds the measuring tube.
  • the position sensor has two circular disks extending in a radial plane to the longitudinal axis, which are connected to one another by a coaxial, radially inwardly offset connecting part in such a way that the axial distance between the flat end faces of the disks corresponds to the axial height of the magnetic ring on the piston.
  • the interior of the measuring tube forms a measuring zone that is independent of the physical condition of the housing interior, a space with constant medium pressure and constant medium density is available for the passage of the measuring radiation, such as ultrasound.
  • the measuring radiation such as ultrasound.
  • a distance measurement can be carried out easily and accurately by means of a distance measuring device having an ultrasonic transmitter/receiver without measures being required for error correction. It goes without saying that a laser measurement can also be carried out via the measuring tube.
  • the position sensor which is made of a ferromagnetic material or is provided with ferromagnetic components, is carried along when the piston moves.
  • a permanent magnet device for example a hard-magnetic ferrite core located in the position transmitter, can also be provided on the position transmitter to generate a particularly high attractive force acting on the position transmitter.
  • a ferrite core can advantageously be provided in the connecting part of the discs, which core has the opposite polarity in the axial direction to the magnet ring.
  • the magnet ring is connected to the piston via an intermediate body made of non-magnetic material.
  • This can be formed from a duroplastic plastic and can be fixed to the piston by screws, which are preferably also non-magnetic.
  • the arrangement can be such that the measuring tube is firmly connected at one end to a housing cover, for example by means of a soldered or welded connection, and engages with its other end in a passage located on the other housing cover and leading to the outside, in which the open end of the tube is sealed against the interior of the housing and a seat for the displacement measuring device is formed.
  • the seat of the housing cover in question can transmit and receive a transmitter/receiver through the open end of the measuring tube record optical or preferably ultrasonic-acoustic measurement radiation passing through.
  • the seat for the path measuring device can be provided on the housing cover adjacent to the oil-side working space.
  • the measuring tube can be connected to the environment on the housing cover, which is opposite the housing cover having the seat of the distance measuring device.
  • the pressure-resistant measuring tube is therefore pressureless, so that no particularly complex seal is required at the passage that forms the seat for the displacement measuring device.
  • the path measuring device can also be removed from the piston accumulator after the measurement periods have been completed without interrupting its operation.
  • the piston accumulator according to the invention shown in the drawing has an accumulator housing designated as a whole by 1, which in both exemplary embodiments shown has a cylinder tube 3 forming a round hollow cylinder as the main part. This is tightly closed at both ends by screwed-in housing covers 5 and 7, between which a piston 9 can be moved freely along the longitudinal axis 11 of the housing.
  • the piston 9 separates a working chamber 13 on the gas side, which accommodates a working gas, such as nitrogen, which is under a filling pressure, as a compressible medium, from a working chamber 15, which accommodates an incompressible medium, such as hydraulic oil.
  • a connection opening 16 is provided in the housing cover 7 adjoining the oil-side working chamber 15, which is arranged in the area between the longitudinal axis 11 and the radially outer end of the housing cover 7.
  • a filling channel 17 is provided, also offset to the longitudinal axis 11, at the outer end of which a filling valve 21 of the usual type is arranged, via which a filling quantity under a filling pressure is fed into the working chamber 13 of the working gas can be introduced.
  • a through-opening 27 is also formed in this housing cover 5 adjoining the working chamber 13 on the gas side.
  • This has the form of a stepped bore with an inner, enlarged bore section 23, which forms a suitable seat for the inserted, open end 25 of a measuring tube 29, in which the open end 25 of the measuring tube 29 is sealed off from the adjacent working space 13.
  • the measuring tube 29 engages in a coaxial through-hole 28 in the housing cover 7 adjoining the working chamber 15 on the oil side.
  • the bore 28 is, in a similar manner to the through-opening 27 on the other housing cover 5, stepped, with the end 26 of the measuring tube 29 being accommodated in a bore section to fit on the sealing elements 19 and 20 the tube end 26 against seal the working space 15.
  • the measuring tube 29 which is made of a pressure-resistant, non-magnetic metallic material, is fixed at its end 25, which sits in the bore section 23 of the housing cover 5 adjoining the gas-side working chamber 13, by means of a soldered or welded connection 24.
  • the measuring tube 29 can extend inside the accumulator housing over its entire length; However, there is also the possibility, in particular at the lower end, of measuring tube 29 to have a pressure-tight end while maintaining an axial distance from housing cover 5 .
  • a central passage 31 is formed in the piston 9 for the measuring tube 29 .
  • the piston 9 is of the type customary for such accumulator pistons and has on its outer circumference deepened annular grooves 33 and 35 for piston seals (not shown), as well as flatter annular grooves 37 and 39, offset from these in the direction of the two axial end regions guide rails not shown.
  • the piston 9 has a round pot-like depression 41 on the side of the piston that faces the gas-side working chamber 13 in the accumulator housing 1, the flat bottom 43 of which is located approximately halfway along the axial length of the piston 9.
  • the passage 31 has a through bore 51 which, coaxially to the longitudinal axis 11, extends from the base 43 to the end face of the piston.
  • the bore has a circular-cylindrical enlargement 53, which forms the seat for an annular body 45, which is fixed in the enlargement 53 by screws 47 running parallel to the bore 51.
  • Annular grooves 49 and 50 are formed in the unexpanded portion of the bore 51 for sealing rings.
  • the annular body 45 fixed in the extension 53 forms the carrier for a permanent magnet device, which generates a magnetic force whose force of attraction acts on a position transmitter 57 that can be displaced in the measuring tube 29 forces the position sensor 57 to follow the movements of the piston 9 in the measuring tube 29 .
  • the permanent magnet device of the piston 9 is formed by a magnet ring 55 which is fixed by gluing to the free surface of the annular body 45 flush with the base 43 .
  • the screws 47 and the annular body 45 are made of thermosetting plastic.
  • the position indicator 57 is made of a ferromagnetic material as a one-piece round body, which has a flat circular disk 58 at each of the two axially opposite ends, on the outer diameter of which the position indicator 57 is displaceably guided in the measuring tube 29 .
  • the discs 58 are connected to one another in one piece via a connecting part 59 which is reduced in diameter.
  • the axial spacing of the discs 58 is adapted to the axial height of the magnet ring 55 in such a way that the end faces of the discs 58 are flush with the axial end faces of the magnet ring 55 so that an optimal magnetic flux is formed with the magnet ring 55 .
  • the end surface of the disc 58 of the position transmitter 57, which faces the end 26 of the measuring tube 29, forms the reflection surface for the measuring radiation entering the measuring tube 29 from the end 26.
  • the stepped bore 28 of the housing cover 7, which accommodates the end 26 of the measuring tube 29, has a circular-cylindrical widening 54 in the same way as is the case with the bore 51 on the passage 31 of the piston 9, in which the same annular body 45 as it is also used as a plastic body on the passage 31 of the piston 9 and is secured by screws 47 .
  • the annular body 45 forms a fitting border for the inserted end section of the measuring tube 29.
  • the path measuring device has a transmitter/receiver 65 for an ultrasonic measuring method, for which the outer, expanded bore portion 67 of the bore 28 in the oil-side housing cover 7 forms a seat. Starting from this bore section 67, an ultrasonic transducer with a disc-shaped piezoceramic 68 extends into the end area of the tube 29 in order to determine the distance to the reflection surface on the facing disc 58 of the position transmitter 57.
  • the embodiment of 2 differs from Fig.1 only insofar as instead of the one-piece connection part 59 with the discs 58 of the position transmitter 57, a hard-magnetic ferrite rod 71 is used as the connection part between the discs 58. This is oriented in such a way that its polarity is opposite to the axial polarity of the magnetic ring 55 so that a strong magnetic force effect results and a particularly reliable tracking of the position transmitter 57 during the movements of the piston 9 is thereby ensured.
  • the ultrasonic measuring method instead of the ultrasonic measuring method, another type of measuring radiation can be used, for example by means of optical methods with laser light or monochromatic visible light.
  • the measuring process can be carried out from an arbitrarily selected end 25 or 26 of the measuring tube 29 .
  • the transmitter/receiver 65 could therefore also be arranged on the gas-side housing cover 5, in which case the widened, end-side bore section 73 of the through-opening 27 could form the seat for the path measuring device.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
  • Length-Measuring Devices Using Wave Or Particle Radiation (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Description

Die Erfindung betrifft einen hydropneumatischen Kolbenspeicher mit den Merkmalen im Oberbegriff des Anspruchs 1.The invention relates to a hydropneumatic piston accumulator having the features in the preamble of claim 1.

Hydrospeicher, wie hydropneumatische Kolbenspeicher, kommen in Hydrauliksystemen zum Einsatz, um bestimmte Volumina unter Druck stehender Flüssigkeit, wie Hydrauliköl, aufzunehmen und bei Bedarf an das System zurückzugeben. Bei den heutzutage üblichen hydropneumatischen Kolbenspeichern, bei denen der Kolben den ölseitigen Arbeitsraum von dem ein Arbeitsgas, wie N2, aufnehmenden Arbeitsraum trennt, verändert sich die Position des Kolbens, so dass der Speicher beim Anstieg des Drucks Hydrauliköl aufnimmt, wobei das Gas im anderen Arbeitsraum komprimiert wird. Bei sinkendem Druck dehnt sich das verdichtete Gas aus und verdrängt dabei gespeichertes Hydrauliköl zurück in den Hydrokreislauf. Durch die sich dadurch im Betrieb ergebenden Veränderungen der Volumina der Arbeitsräume ergibt sich jeweils eine entsprechende Axialbewegung des Kolbens.Hydraulic accumulators, such as hydropneumatic piston accumulators, are used in hydraulic systems to take up certain volumes of pressurized liquid, such as hydraulic oil, and return it to the system when required. With the hydropneumatic piston accumulators that are common today, in which the piston separates the oil-side working chamber from the working chamber that accommodates a working gas, such as N 2 , the position of the piston changes so that the accumulator absorbs hydraulic oil when the pressure rises, with the gas in the other Working space is compressed. When the pressure drops, the compressed gas expands, pushing stored hydraulic oil back into the hydraulic circuit. The resulting changes in the volumes of the working chambers during operation result in a corresponding axial movement of the piston.

Für das gewünschte, einwandfreie Betriebsverhalten des Speichers ist Voraussetzung, dass der im Arbeitsraum des Arbeitsgases herrschende Druck an das Druckniveau im ölseitigen Arbeitsraum angepasst ist, so dass sich der Kolben an geeigneten Stellen innerhalb des Speichergehäuses befindet und dadurch die Arbeitsbewegungen zwischen Kolben-Endpositionen im Speichergehäuse durchführen kann. Die Ermittlung der Position, die der Kolben bei einem gegebenen Flüssigkeitsdruck im ölseitigen Arbeitsraum einnimmt, ermöglicht zudem eine Feststellung über die Höhe des Fülldrucks des Arbeitsgases im zugehörigen Arbeitsraum und damit eine Überwachung des Kolbenspeichers auf ordnungsgemäße Funktionsfähigkeit.For the desired, perfect operating behavior of the accumulator, it is a prerequisite that the pressure prevailing in the working chamber of the working gas is adapted to the pressure level in the oil-side working chamber, so that the piston is located at suitable points within the accumulator housing and thereby can carry out the working movements between piston end positions in the accumulator housing. Determining the position that the piston assumes at a given fluid pressure in the oil-side working chamber also enables the level of filling pressure of the working gas in the associated working chamber to be determined and thus allows the piston accumulator to be monitored for proper functionality.

Zur Positionsfeststellung des Kolbens wurden verschiedene Lösungen vorgeschlagen. Aus dem Dokument DE 10 2013 009 614 A1 ist beispielsweise ein Ultraschall-Wegmesssystem bekannt, bei dem, ausgehend von dem an den das Arbeitsgas enthaltenden Arbeitsraum angrenzenden Gehäusedeckel, mittels eines Ultraschallsensors der Abstand zur zugewandten Seite des Kolbens ermittelt wird. Diese Lösung ist insofern aufwendig, als wegen der im Betrieb sich ändernden Schallausbreitungsgeschwindigkeit im das Gas enthaltenden Arbeitsraum eine fortlaufende Fehlerkorrektur des aufgrund einer Laufzeitermittlung erhaltenen Messergebnisses durchzuführen ist. Bei einer weiteren bekannten Lösung, die in DE 103 10 427 A1 offenbart ist, sind an der Außenseite des Speichergehäuses entlang einer Reihe angeordnete Magnetfeldsensoren angeordnet, die auf das Feld einer Magnetanordnung ansprechen, die sich am Kolben des Kolbenspeichers befindet. Diese Lösung lässt insofern zu wünschen übrig, als eine die Magnetfeldsensoren enthaltende Magnetleiste als äußeres Bauteil am Speichergehäuse anzubauen ist.Various solutions have been proposed for detecting the position of the piston. From the document DE 10 2013 009 614 A1 For example, an ultrasonic distance measuring system is known in which, starting from the housing cover adjacent to the working chamber containing the working gas, the distance to the facing side of the piston is determined by means of an ultrasonic sensor. This solution is complex insofar as a continuous error correction of the measurement result obtained on the basis of a propagation time determination has to be carried out because of the speed of sound propagation in the working space containing the gas, which changes during operation. In another known solution, which is DE 103 10 427 A1 discloses magnetic field sensors arranged on the outside of the accumulator housing along a line responsive to the field of a magnet assembly located on the piston of the piston accumulator. This solution leaves a lot to be desired insofar as a magnetic strip containing the magnetic field sensors has to be attached to the storage housing as an external component.

Die JP H07 269503 offenbart einen hydropneumatischen Kolbenspeicher mit einem Speichergehäuse, das ein eine Längsachse definierendes Zylinderrohr aufweist, das an beiden Enden durch jeweils einen Gehäusedeckel geschlossen ist und in dem ein Kolben längsverfahrbar ist, der im Gehäuse einen Arbeitsraum für ein kompressibles Medium, wie ein Arbeitsgas, von einem Arbeitsraum für ein inkompressibles Medium, wie Hydrauliköl, trennt, und mit einer die Position des Kolbens im Gehäuse berührungslos ermittelnden Wegmesseinrichtung, die ein nichtmagnetisches Messrohr aufweist, das sich durch eine im Kolben gebildete Durchführung entlang der Längsachse von einem Gehäusedeckel zum anderen Gehäusedeckel hin erstreckt und gegen den Innenraum des Gehäuses abgedichtet ist.The JP H07 269503 discloses a hydropneumatic piston accumulator with an accumulator housing which has a cylinder tube defining a longitudinal axis, which is closed at both ends by a respective housing cover and in which a piston can be moved longitudinally, which in the housing has a working space for a compressible medium, such as a working gas, from a Working space for an incompressible medium, such as hydraulic oil, separates, and with a non-contact position of the piston in the housing determining distance measuring device, which has a non-magnetic measuring tube, which extends through a passage formed in the piston along the longitudinal axis from one housing cover to the other housing cover and is sealed against the interior of the housing.

Die JP S62 97307 U beschreibt einen Arbeitszylinder mit einem Messrohr, in dem ein Positionsgeber verschiebbar geführt ist, der durch eine zwischen ihm und einem Kolben des Arbeitszylinders wirkende Magnetkraft im Messrohr den Kolbenbewegungen nachfolgt, wobei an einem Gehäusedeckel des Arbeitszylinders ein Sender/Empfänger einer Wegmesseinrichtung angeordnet ist, der durch ein offenes Ende des Messrohres hindurchtretende Messstrahlung zum Positionsgeber aussendet und von diesem reflektierte Strahlung empfängt.The JP S62 97307 U describes a working cylinder with a measuring tube, in which a position sensor is slidably guided, which follows the piston movements in the measuring tube by a magnetic force acting between it and a piston of the working cylinder, with a transmitter/receiver of a displacement measuring device being arranged on a housing cover of the working cylinder, which is emits measuring radiation passing through an open end of the measuring tube to the position transmitter and receives radiation reflected from it.

Die DE 71 03 342 U offenbart einen weiteren Hydrospeicher und die DE 10 2004 057 769 A1 beschreibt einen weiteren Arbeitszylinder.The DE 71 03 342 U discloses another hydraulic accumulator and the DE 10 2004 057 769 A1 describes another working cylinder.

Ausgehend von diesem Stand der Technik stellt sich die Erfindung die Aufgabe, einen hydropneumatischen Kolbenspeicher der eingangs genannten Art zur Verfügung zu stellen, dessen Wegmesseinrichtung die Positionsermittlung des Kolbens auf besonders einfache und vorteilhafte Weise ermöglicht.Proceeding from this state of the art, the object of the invention is to provide a hydropneumatic piston accumulator of the type mentioned at the outset, the travel measuring device of which enables the position of the piston to be determined in a particularly simple and advantageous manner.

Erfindungsgemäß ist diese Aufgabe durch einen Kolbenspeicher gelöst, der die Merkmale des Patentanspruchs 1 in seiner Gesamtheit aufweist.According to the invention, this object is achieved by a piston accumulator which has the features of claim 1 in their entirety.

Entsprechend dem kennzeichnenden Teil des Anspruchs 1 folgt ein für den Messvorgang dienender Positionsgeber, der im Messrohr verschiebbar geführt ist, unter Einwirkung einer zwischen Kolben und Positionsgeber wirkenden Magnetkraft im Messrohr den Bewegungen des Kolbens nach. Ein an einem Gehäusedeckel befindlicher Sender/Empfänger der Wegmesseinrichtung sendet durch das betreffende offene Ende des Messrohres hindurch eine Messstrahlung zum Positionsgeber und empfängt von diesem reflektierte Strahlung. Zur Erzeugung der die Folgebewegungen des Positionsgebers im Messrohr erzwingenden Magnetkraft ist einen an der Durchführung des Kolbens festgelegten, das Messrohr umgebenden Magnetring vorgesehen.According to the characterizing part of claim 1, a position sensor serving for the measuring process, which is slidably guided in the measuring tube, follows the movements of the piston under the influence of a magnetic force acting between the piston and position sensor in the measuring tube. A transmitter/receiver of the distance measuring device located on a housing cover transmits a measurement radiation through the relevant open end of the measuring tube to the position transmitter and receives radiation reflected from it. In order to generate the magnetic force that forces the subsequent movements of the position transmitter in the measuring tube, a magnetic ring is provided which is fixed to the passage of the piston and surrounds the measuring tube.

Der Positionsgeber weist zwei sich in einer Radialebene zur Längsachse erstreckende kreisrunde Scheiben auf, die durch ein koaxiales, radial nach innen versetztes Verbindungsteil derart miteinander verbunden sind, dass der axiale Abstand der ebenen Endflächen der Scheiben der axialen Höhe des Magnetringes am Kolben entspricht.The position sensor has two circular disks extending in a radial plane to the longitudinal axis, which are connected to one another by a coaxial, radially inwardly offset connecting part in such a way that the axial distance between the flat end faces of the disks corresponds to the axial height of the magnetic ring on the piston.

Bei der axialen Polung des Magnetringes ergibt sich über die Scheiben des Positionsgebers eine hohe magnetische Flussdichte und eine hohe, die sichere Folgebewegung des Positionsgebers erzwingende Magnetkraftwirkung.With the axial polarity of the magnetic ring, a high magnetic flux density and a high magnetic force effect, which forces the safe subsequent movement of the position transmitter, are produced via the disks of the position transmitter.

Dadurch, dass der Innenraum des Messrohres eine vom physikalischen Zustand des Gehäuseinnenraums unabhängige Messzone bildet, steht für den Durchtritt der Messstrahlung, wie Ultraschall, ein Raum mit gleichbleibendem Mediendruck und gleichbleibender Mediendichte zur Verfügung. Bei somit konstanter Schallgeschwindigkeit ist eine Wegmessung mittels einer einen Ultraschallsender/-empfänger aufweisenden Wegmesseinrichtung, ohne dass Maßnahmen für eine Fehlerkorrektur erforderlich wären, problemlos und genau durchführbar. Es versteht sich, dass über das Messrohr gleichermaßen auch eine Lasermessung durchführbar ist.Because the interior of the measuring tube forms a measuring zone that is independent of the physical condition of the housing interior, a space with constant medium pressure and constant medium density is available for the passage of the measuring radiation, such as ultrasound. With a constant speed of sound, a distance measurement can be carried out easily and accurately by means of a distance measuring device having an ultrasonic transmitter/receiver without measures being required for error correction. It goes without saying that a laser measurement can also be carried out via the measuring tube.

Der Positionsgeber, der aus einem ferromagnetischen Werkstoff gebildet ist oder mit ferromagnetischen Bestandteilen versehen ist, ist bei den Verfahrbewegungen des Kolbens mitgenommen.The position sensor, which is made of a ferromagnetic material or is provided with ferromagnetic components, is carried along when the piston moves.

Für die Erzeugung einer besonders hohen, am Positionsgeber wirkenden Anziehungskraft kann auch am Positionsgeber eine Permanentmagneteinrichtung vorgesehen sein, beispielsweise ein im Positionsgeber befindlicher, hartmagnetischer Ferritkern.A permanent magnet device, for example a hard-magnetic ferrite core located in the position transmitter, can also be provided on the position transmitter to generate a particularly high attractive force acting on the position transmitter.

Als Permanentmagneteinrichtung am Positionsgeber kann mit Vorteil im Verbindungsteil der Scheiben ein Ferritkern vorgesehen sein, der in Axialrichtung umgekehrt zum Magnetring gepolt ist.As a permanent magnet device on the position transmitter, a ferrite core can advantageously be provided in the connecting part of the discs, which core has the opposite polarity in the axial direction to the magnet ring.

Für die magnetische Entkopplung des Magnetringes gegenüber dem Kolbenwerkstoff ist bei vorteilhaften Ausführungsbeispielen der Magnetring mit dem Kolben über einen aus nichtmagnetischem Werkstoff bestehenden Zwischenkörper verbunden. Dieser kann aus einem duroplastischen Kunststoff gebildet sein und durch Schrauben, die vorzugsweise ebenfalls nicht magnetisch sind, am Kolben festgelegt sein.For the magnetic decoupling of the magnet ring from the piston material, in advantageous exemplary embodiments, the magnet ring is connected to the piston via an intermediate body made of non-magnetic material. This can be formed from a duroplastic plastic and can be fixed to the piston by screws, which are preferably also non-magnetic.

Mit Vorteil kann die Anordnung so getroffen sein, dass das Messrohr an einem Ende mit einem Gehäusedeckel fest verbunden ist, beispielsweise mittels einer Löt- oder Schweißverbindung, und mit seinem anderen Ende in einen am anderen Gehäusedeckel befindlichen, nach außen führenden Durchgang eingreift, in dem das offene Ende des Rohres gegen den Gehäuseinnenraum abgedichtet und ein Sitz für die Wegmesseinrichtung gebildet ist.Advantageously, the arrangement can be such that the measuring tube is firmly connected at one end to a housing cover, for example by means of a soldered or welded connection, and engages with its other end in a passage located on the other housing cover and leading to the outside, in which the open end of the tube is sealed against the interior of the housing and a seat for the displacement measuring device is formed.

Dabei kann der Sitz des betreffenden Gehäusedeckels den Sender/Empfänger für Abgabe und Empfang einer durch das offene Ende des Messrohres hindurchtretenden optischen oder vorzugsweise ultraschall-akustischen Messstrahlung aufnehmen.The seat of the housing cover in question can transmit and receive a transmitter/receiver through the open end of the measuring tube record optical or preferably ultrasonic-acoustic measurement radiation passing through.

Der Sitz für die Wegmesseinrichtung kann an dem an den ölseitigen Arbeitsraum angrenzenden Gehäusedeckel vorgesehen sein. In vorteilhafter Weise befinden sich dadurch die Anschlussverbindungen der Wegmesseinrichtung und auch die zum zugeordneten Hydrauliksystem führende Rohrleitung, die mit einer Anschlussöffnung verbunden ist, die sich an diesem Gehäusedeckel befindet, auf ein und derselben Seite des Speichergehäuses.The seat for the path measuring device can be provided on the housing cover adjacent to the oil-side working space. As a result, the connections of the travel measuring device and also the pipeline leading to the associated hydraulic system, which is connected to a connection opening located on this housing cover, are advantageously located on one and the same side of the accumulator housing.

An dem Gehäusedeckel, der dem den Sitz der Wegmesseinrichtung aufweisenden Gehäusedeckel gegenüberliegt, kann das Messrohr mit der Umgebung in Verbindung sein. Das druckfest ausgebildete Messrohr ist somit drucklos, so dass an dem Durchgang, der den Sitz für die Wegmesseinrichtung bildet, keine besonders aufwendige Abdichtung erforderlich ist. Bei drucklosem Messrohr kann auch die Wegmesseinrichtung nach Abschluss durchgeführter Messperioden aus dem Kolbenspeicher herausgenommen werden, ohne dessen Betrieb zu unterbrechen.The measuring tube can be connected to the environment on the housing cover, which is opposite the housing cover having the seat of the distance measuring device. The pressure-resistant measuring tube is therefore pressureless, so that no particularly complex seal is required at the passage that forms the seat for the displacement measuring device. When the measuring tube is depressurized, the path measuring device can also be removed from the piston accumulator after the measurement periods have been completed without interrupting its operation.

Nachstehend ist die Erfindung anhand von in der Zeichnung dargestellten Ausführungsbeispielen im Einzelnen erläutert.The invention is explained in detail below with reference to exemplary embodiments illustrated in the drawing.

Es zeigen:

Fig. 1
einen verkürzt dargestellten Längsschnitt eines Ausführungsbeispiels des erfindungsgemäßen Kolbenspeichers; und
Fig. 2
einen ebenfalls verkürzt dargestellten Längsschnitt eines zweiten Ausführungsbeispiels.
Show it:
1
a shortened longitudinal section of an embodiment of the piston accumulator according to the invention; and
2
a longitudinal section of a second embodiment, also shown in abbreviated form.

Der in der Zeichnung dargestellte, erfindungsgemäße Kolbenspeicher weist ein als Ganzes mit 1 bezeichnetes Speichergehäuse auf, das bei beiden gezeigten Ausführungsbeispielen als Hauptteil ein einen runden Hohlzylinder bildendes Zylinderrohr 3 aufweist. Dieses ist an beiden Enden durch jeweils einen eingeschraubten Gehäusedeckel 5 und 7 dicht verschlossen, zwischen denen ein Kolben 9 entlang der Gehäuselängsachse 11 frei verfahrbar ist. Der Kolben 9 trennt einen gasseitigen Arbeitsraum 13, der als kompressibles Medium ein Arbeitsgas, wie Stickstoff das unter einem Fülldruck steht, aufnimmt, von einem Arbeitsraum 15, der ein inkompressibles Medium, wie Hydrauliköl, aufnimmt. Für die Verbindung dieses Arbeitsraumes 15 mit einem zugeordneten Hydrauliksystem, das nicht dargestellt ist, ist in dem an den ölseitigen Arbeitsraum 15 angrenzenden Gehäusedeckel 7 eine Anschlussöffnung 16 vorgesehen, die im Bereich zwischen der Längsachse 11 und dem radial außenliegenden Ende des Gehäusedeckels 7 angeordnet ist. Am gegenüberliegenden Gehäusedeckel 5, der an den gasseitigen Arbeitsraum 13 angrenzt, ist, zur Längsachse 11 ebenfalls versetzt, ein Füllkanal 17 vorgesehen, an dessen äußerem Ende ein Füllventil 21 üblicher Art angeordnet ist, über das in den Arbeitsraum 13 eine unter einem Fülldruck stehende Füllmenge des Arbeitsgases einbringbar ist. In zur Längsachse 11 koaxialer Anordnung ist in diesem an den gasseitigen Arbeitsraum 13 angrenzenden Gehäusedeckel 5 auch eine Durchgangsöffnung 27 ausgebildet. Diese hat die Form einer gestuften Bohrung mit einem inneren, erweiterten Bohrungsabschnitt 23, der einen passenden Sitz für das eingesteckte, offene Ende 25 eines Messrohres 29 bildet, in dem das offene Ende 25 des Messrohres 29 gegenüber dem angrenzenden Arbeitsraum 13 abgedichtet ist. Mit seinem gegenüberliegenden Ende 26 greift das Messrohr 29 in eine koaxiale Durchgangsbohrung 28 in dem an den ölseitigen Arbeitsraum 15 angrenzenden Gehäusedeckel 7 ein. Die Bohrung 28 ist, in ähnlicher Weise wie die Durchgangsöffnung 27 am anderen Gehäusedeckel 5, gestuft, wobei das Ende 26 des Messrohres 29 in einem Bohrungsabschnitt passend aufgenommen ist, an dem Dichtelemente 19 und 20 das Rohrende 26 gegen den Arbeitsraum 15 abdichten. Das Messrohr 29, das aus einem druckfesten, nichtmagnetischen metallischen Werkstoff gebildet ist, ist an seinem Ende 25, das in dem Bohrungsabschnitt 23 des an den gasseitigen Arbeitsraum 13 angrenzenden Gehäusedeckels 5 sitzt, an diesem mittels einer Löt- oder Schweißverbindung 24 festgelegt. Das Messrohr 29 kann sich im Innern des Speichergehäuses über dessen gesamte Länge erstrecken; es besteht aber auch die Möglichkeit, insbesondere am unteren Ende das Messrohr 29 unter Beibehalten eines axialen Abstandes zum Gehäusedeckel 5 dieses druckdicht enden zu lassen.The piston accumulator according to the invention shown in the drawing has an accumulator housing designated as a whole by 1, which in both exemplary embodiments shown has a cylinder tube 3 forming a round hollow cylinder as the main part. This is tightly closed at both ends by screwed-in housing covers 5 and 7, between which a piston 9 can be moved freely along the longitudinal axis 11 of the housing. The piston 9 separates a working chamber 13 on the gas side, which accommodates a working gas, such as nitrogen, which is under a filling pressure, as a compressible medium, from a working chamber 15, which accommodates an incompressible medium, such as hydraulic oil. For the connection of this working chamber 15 with an associated hydraulic system, which is not shown, a connection opening 16 is provided in the housing cover 7 adjoining the oil-side working chamber 15, which is arranged in the area between the longitudinal axis 11 and the radially outer end of the housing cover 7. On the opposite housing cover 5, which adjoins the gas-side working chamber 13, a filling channel 17 is provided, also offset to the longitudinal axis 11, at the outer end of which a filling valve 21 of the usual type is arranged, via which a filling quantity under a filling pressure is fed into the working chamber 13 of the working gas can be introduced. In an arrangement coaxial to the longitudinal axis 11 , a through-opening 27 is also formed in this housing cover 5 adjoining the working chamber 13 on the gas side. This has the form of a stepped bore with an inner, enlarged bore section 23, which forms a suitable seat for the inserted, open end 25 of a measuring tube 29, in which the open end 25 of the measuring tube 29 is sealed off from the adjacent working space 13. With its opposite end 26 , the measuring tube 29 engages in a coaxial through-hole 28 in the housing cover 7 adjoining the working chamber 15 on the oil side. The bore 28 is, in a similar manner to the through-opening 27 on the other housing cover 5, stepped, with the end 26 of the measuring tube 29 being accommodated in a bore section to fit on the sealing elements 19 and 20 the tube end 26 against seal the working space 15. The measuring tube 29, which is made of a pressure-resistant, non-magnetic metallic material, is fixed at its end 25, which sits in the bore section 23 of the housing cover 5 adjoining the gas-side working chamber 13, by means of a soldered or welded connection 24. The measuring tube 29 can extend inside the accumulator housing over its entire length; However, there is also the possibility, in particular at the lower end, of measuring tube 29 to have a pressure-tight end while maintaining an axial distance from housing cover 5 .

Für das Messrohr 29 ist im Kolben 9 eine zentrale Durchführung 31 gebildet. Ansonsten ist der Kolben 9 in der bei derartigen Speicherkolben üblichen Art ausgebildet und weist an seinem Außenumfang vertiefte Ringnuten 33 und 35 für nicht gezeigte Kolbendichtungen auf, sowie, zu diesen in Richtung auf die beiden axialen Endbereiche hin versetzt, flachere Ringnuten 37 und 39 für ebenfalls nicht gezeigte Führungsleisten auf. Wie ebenfalls bei derartigen Kolben üblich, weist der Kolben 9 an der Kolbenseite, die im Speichergehäuse 1 dem gasseitigen Arbeitsraum 13 zugewandt ist, eine runde topfartige Vertiefung 41 auf, deren ebener Boden 43 auf etwa halber axialer Länge des Kolbens 9 gelegen ist. Die Durchführung 31 weist eine Durchgangsbohrung 51 auf, die sich, zur Längsachse 11 koaxial, vom Boden 43 ausgehend bis zur Kolbenstirnseite erstreckt. An dem an den Boden 43 angrenzenden Bohrungsbereich weist die Bohrung eine kreiszylindrische Erweiterung 53 auf, die den Sitz für einen Ringkörper 45 bildet, der durch zur Bohrung 51 parallel verlaufende Schrauben 47 in der Erweiterung 53 festgelegt ist. Ringnuten 49 und 50 sind im nicht erweiterten Teil der Bohrung 51 für Dichtringe ausgebildet.A central passage 31 is formed in the piston 9 for the measuring tube 29 . Otherwise, the piston 9 is of the type customary for such accumulator pistons and has on its outer circumference deepened annular grooves 33 and 35 for piston seals (not shown), as well as flatter annular grooves 37 and 39, offset from these in the direction of the two axial end regions guide rails not shown. As is also usual with pistons of this type, the piston 9 has a round pot-like depression 41 on the side of the piston that faces the gas-side working chamber 13 in the accumulator housing 1, the flat bottom 43 of which is located approximately halfway along the axial length of the piston 9. The passage 31 has a through bore 51 which, coaxially to the longitudinal axis 11, extends from the base 43 to the end face of the piston. In the bore area adjacent to the base 43, the bore has a circular-cylindrical enlargement 53, which forms the seat for an annular body 45, which is fixed in the enlargement 53 by screws 47 running parallel to the bore 51. Annular grooves 49 and 50 are formed in the unexpanded portion of the bore 51 for sealing rings.

Der in der Erweiterung 53 festgelegte Ringkörper 45 bildet den Träger für eine Permanentmagneteinrichtung, die eine Magnetkraft erzeugt, deren auf einen im Messrohr 29 verschiebbaren Positionsgeber 57 einwirkende Anziehungskraft den Positionsgeber 57 zwingt, im Messrohr 29 den Verfahrbewegungen des Kolbens 9 zu folgen. Erfindungsgemäß ist die Permanentmagneteinrichtung des Kolbens 9 durch einen Magnetring 55 gebildet, der an der mit dem Boden 43 fluchtenden freien Fläche des Ringkörpers 45 durch Kleben festgelegt ist. Für die magnetische Entkopplung des Magnetringes 55 vom metallischen Kolben 9 sind die Schrauben 47 und der Ringkörper 45 aus duroplastischem Kunststoff.The annular body 45 fixed in the extension 53 forms the carrier for a permanent magnet device, which generates a magnetic force whose force of attraction acts on a position transmitter 57 that can be displaced in the measuring tube 29 forces the position sensor 57 to follow the movements of the piston 9 in the measuring tube 29 . According to the invention, the permanent magnet device of the piston 9 is formed by a magnet ring 55 which is fixed by gluing to the free surface of the annular body 45 flush with the base 43 . For the magnetic decoupling of the magnet ring 55 from the metallic piston 9, the screws 47 and the annular body 45 are made of thermosetting plastic.

Bei dem Ausführungsbeispiel von Fig. 1 ist der Positionsgeber 57 aus einem ferromagnetischen Werkstoff als einstückiger Rundkörper ausgebildet, der an beiden axial einander entgegengesetzten Enden je eine ebene Kreisscheibe 58 aufweist, an deren Außendurchmesser der Positionsgeber 57 im Messrohr 29 verschiebbar geführt ist. Die Scheiben 58 sind über ein im Durchmesser verringertes Verbindungsteil 59 einstückig miteinander verbunden. Der axiale Abstand der Scheiben 58 ist der axialen Höhe des Magnetringes 55 derart angepasst, dass die Endflächen der Scheiben 58 mit den axialen Endflächen des Magnetringes 55 fluchten, so dass ein optimaler Magnetfluss mit dem Magnetring 55 gebildet ist. Die Endfläche der Scheibe 58 des Positionsgebers 57, die dem Ende 26 des Messrohres 29 zugewandt ist, bildet die Reflexionsfläche für vom Ende 26 her in das Messrohr 29 eintretende Messstrahlung.In the embodiment of 1 the position indicator 57 is made of a ferromagnetic material as a one-piece round body, which has a flat circular disk 58 at each of the two axially opposite ends, on the outer diameter of which the position indicator 57 is displaceably guided in the measuring tube 29 . The discs 58 are connected to one another in one piece via a connecting part 59 which is reduced in diameter. The axial spacing of the discs 58 is adapted to the axial height of the magnet ring 55 in such a way that the end faces of the discs 58 are flush with the axial end faces of the magnet ring 55 so that an optimal magnetic flux is formed with the magnet ring 55 . The end surface of the disc 58 of the position transmitter 57, which faces the end 26 of the measuring tube 29, forms the reflection surface for the measuring radiation entering the measuring tube 29 from the end 26.

Die das Ende 26 des Messrohres 29 aufnehmende gestufte Bohrung 28 des Gehäusedeckels 7 weist in gleicher Weise, wie dies bei der Bohrung 51 an der Durchführung 31 des Kolbens 9 der Fall ist, eine kreiszylindrische Erweiterung 54 auf, in der der gleiche Ringkörper 45, wie er auch an der Durchführung 31 des Kolbens 9 als Kunststoffkörper benutzt wird, aufgenommen und durch Schrauben 47 gesichert ist. Der Ringkörper 45 bildet am Gehäusedeckel 7 eine passende Einfassung des eingesteckten Endabschnitts des Messrohres 29. Die Wegmesseinrichtung weist für ein Ultraschall-Messverfahren einen Sender/Empfänger 65 auf, für den der äußere, erweiterte Bohrungsabschnitt 67 der Bohrung 28 im ölseitigen Gehäusedeckel 7 einen Sitz bildet. Von diesem Bohrungsabschnitt 67 ausgehend, erstreckt sich ein Ultraschallwandler mit einer scheibenförmigen Piezokeramik 68 in den Endbereich des Rohres 29 hinein, um die Abstandsbestimmung zur Reflexionsfläche an der zugewandten Scheibe 58 des Positionsgebers 57 durchzuführen.The stepped bore 28 of the housing cover 7, which accommodates the end 26 of the measuring tube 29, has a circular-cylindrical widening 54 in the same way as is the case with the bore 51 on the passage 31 of the piston 9, in which the same annular body 45 as it is also used as a plastic body on the passage 31 of the piston 9 and is secured by screws 47 . On the housing cover 7, the annular body 45 forms a fitting border for the inserted end section of the measuring tube 29. The path measuring device has a transmitter/receiver 65 for an ultrasonic measuring method, for which the outer, expanded bore portion 67 of the bore 28 in the oil-side housing cover 7 forms a seat. Starting from this bore section 67, an ultrasonic transducer with a disc-shaped piezoceramic 68 extends into the end area of the tube 29 in order to determine the distance to the reflection surface on the facing disc 58 of the position transmitter 57.

Das Ausführungsbeispiel von Fig. 2 unterscheidet sich gegenüber Fig.1 lediglich insofern, als anstelle des mit den Scheiben 58 des Positionsgebers 57 einstückigen Verbindungsteils 59 als Verbindungsteil zwischen die Scheiben 58 ein hartmagnetischer Ferritstab 71 eingesetzt ist. Dieser ist so orientiert, dass seine Polung der axialen Polung des Magnetringes 55 entgegengesetzt ist, so dass eine starke Magnetkraftwirkung resultiert und dadurch eine besonders sichere Nachführung des Positionsgebers 57 bei den Verfahrbewegungen des Kolbens 9 gewährleistet ist.The embodiment of 2 differs from Fig.1 only insofar as instead of the one-piece connection part 59 with the discs 58 of the position transmitter 57, a hard-magnetic ferrite rod 71 is used as the connection part between the discs 58. This is oriented in such a way that its polarity is opposite to the axial polarity of the magnetic ring 55 so that a strong magnetic force effect results and a particularly reliable tracking of the position transmitter 57 during the movements of the piston 9 is thereby ensured.

Es versteht sich, dass anstelle des Ultraschall-Messverfahrens mit andersartiger Messstrahlung gearbeitet werden kann, beispielsweise mittels optischer Verfahren mit Laserlicht oder monochromatischem sichtbaren Licht. Bei gegenüber dem Gehäuseinnenraum isolierter, im Messrohr 29 eingeschlossener Messzone kann der Messvorgang von einem beliebig gewählten Ende 25 oder 26 des Messrohres 29 her durchgeführt werden. Anders als gezeigt könnte daher der Sender/Empfänger 65 auch am gasseitigen Gehäusedeckel 5 angeordnet sein, wobei der erweiterte, endseitige Bohrungsabschnitt 73 der Durchgangsöffnung 27 den Sitz für die Wegmesseinrichtung bilden könnte.It goes without saying that, instead of the ultrasonic measuring method, another type of measuring radiation can be used, for example by means of optical methods with laser light or monochromatic visible light. With the measuring zone enclosed in the measuring tube 29 and isolated from the interior of the housing, the measuring process can be carried out from an arbitrarily selected end 25 or 26 of the measuring tube 29 . In contrast to what is shown, the transmitter/receiver 65 could therefore also be arranged on the gas-side housing cover 5, in which case the widened, end-side bore section 73 of the through-opening 27 could form the seat for the path measuring device.

Claims (7)

  1. Hydropneumatic piston accumulator, having an accumulator housing (1) which comprises a cylinder tube (3), defining a longitudinal axis (11), which cylinder tube is closed at both ends by a housing cover (5, 7) in each case and in which a piston (9) is longitudinally movable in the housing, which piston separates a working chamber (13) for a compressible medium, such as a working gas, from a working chamber for an incompressible medium, such as hydraulic oil, and having a displacement measuring device, which contactlessly determines the position of the piston (9) in the housing, which displacement measuring device comprises a non-magnetic measuring tube (29) which extends through a lead-through (31) formed in the piston (9) along the longitudinal axis (11) from one housing cover (5) to the other housing cover (7) and is sealed off from the interior of the housing (1), characterised in that a position generator (57) is displaceably guided in the tube (29) and follows the piston movements in the measuring tube (29) by magnetic force acting between it and the piston (9), whereby a transmitter/receiver (65) of the displacement measuring device is arranged at one end of the housing cover (5, 7), which transmitter/receiver transmits measuring radiation passing through the relevant open end (25, 26) of the measuring tube (29) to the position generator (57) and receives reflected radiation from the latter, wherein a magnetic ring (55) fixed to the lead-through (31) of the piston (9) and surrounding the measuring tube (29) is provided for generating the magnetic force compelling the following movements of the position generator (57) in the measuring tube (29), wherein the position generator (57) comprises two circular discs (58) extending in a radial plane to the longitudinal axis (11), which circular discs are connected together by a coaxial connecting part (59; 71), offset radially inwards, in such a manner that the axial spacing of the flat end surfaces of the discs (58) corresponds to the axial height of a magnetic ring (55) on the piston (9).
  2. Piston accumulator according to claim 1, characterised in that a permanent magnet device (71) is also provided on the position generator (57) to compel the magnetic force compelling the following movements of the position generator (57) in the measuring tube (29).
  3. Piston accumulator according to claim 1 or 2, characterised in that the magnetic ring (55) is connected to the piston (9) via an intermediate body (45) consisting of non-magnetic material.
  4. Piston accumulator according to one of the preceding claims, characterised in that the measuring tube (29) is fixedly connected at one end (25) to a housing cover (5) and engaged with its other end (26) in an outwardly leading passage (28) located on the other housing cover (7), in which passage the open end (26) of the tube (29) is sealed off from the housing interior and a seat (67) for the displacement measuring device is formed.
  5. Piston accumulator according to claim 4, characterised in that the seat (67) of the relevant housing cover (7) accommodates the transmitter/receiver (65) for emitting and receiving optical or preferably acoustic measuring radiation which passes through the open end (26) of the measuring tube (29).
  6. Piston accumulator according to claim 4 or 5, characterised in that the seat (67) for the displacement measuring device is provided on the housing cover (7) adjoining the oil-side working chamber (15).
  7. Piston accumulator according to one of claims 4 to 6, characterised in that the measuring tube (29) is in communication with the environment at the housing cover (5) which opposes the housing cover (7) that has the seat (67) of the displacement measuring device.
EP17717082.6A 2016-06-25 2017-04-11 Hydropneumatic piston accumulator Active EP3475583B1 (en)

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DE102016007798.0A DE102016007798A1 (en) 2016-06-25 2016-06-25 Hydropneumatic piston accumulator
PCT/EP2017/000469 WO2017220179A1 (en) 2016-06-25 2017-04-11 Hydropneumatic piston accumulator

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CN112762028B (en) * 2021-01-18 2022-07-05 国家石油天然气管网集团有限公司华南分公司 Voltage-stabilizing closed oil tank

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EP3475583C0 (en) 2023-06-07
EP3475584B1 (en) 2022-08-10
EP4230874A3 (en) 2023-08-30
EP3475583A1 (en) 2019-05-01
WO2017220196A1 (en) 2017-12-28
WO2017220179A1 (en) 2017-12-28
EP3475584A1 (en) 2019-05-01
JP2019521294A (en) 2019-07-25
US10941789B2 (en) 2021-03-09
JP2019519739A (en) 2019-07-11
US20200309158A1 (en) 2020-10-01
US10781830B2 (en) 2020-09-22
EP4230874A2 (en) 2023-08-23
US20190120257A1 (en) 2019-04-25

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