EP1685323B1 - Device for damping pressure surges - Google Patents

Device for damping pressure surges Download PDF

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Publication number
EP1685323B1
EP1685323B1 EP04790081A EP04790081A EP1685323B1 EP 1685323 B1 EP1685323 B1 EP 1685323B1 EP 04790081 A EP04790081 A EP 04790081A EP 04790081 A EP04790081 A EP 04790081A EP 1685323 B1 EP1685323 B1 EP 1685323B1
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EP
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Prior art keywords
piston
housing
further piston
connecting piece
fluid
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EP04790081A
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German (de)
French (fr)
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EP1685323A1 (en
Inventor
Norbert Weber
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Hydac Technology GmbH
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Hydac Technology GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M37/00—Apparatus or systems for feeding liquid fuel from storage containers to carburettors or fuel-injection apparatus; Arrangements for purifying liquid fuel specially adapted for, or arranged on, internal-combustion engines
    • F02M37/0011—Constructional details; Manufacturing or assembly of elements of fuel systems; Materials therefor
    • F02M37/0041—Means for damping pressure pulsations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/04—Means for damping vibrations or pressure fluctuations in injection pump inlets or outlets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/31—Fuel-injection apparatus having hydraulic pressure fluctuations damping elements
    • F02M2200/315—Fuel-injection apparatus having hydraulic pressure fluctuations damping elements for damping fuel pressure fluctuations

Definitions

  • the invention relates to a device for damping pressure surges in a fluid with a housing and a longitudinally movable against the biasing force of a spring accumulator in the housing piston according to the feature configuration of the preamble of claim 1.
  • the devices in question include the so-called hydraulic accumulators, one of the main tasks of hydraulic accumulators being to take up certain volumes of pressurized fluid from a hydraulic system and, if necessary, to return them to the system. Since the fluid is under pressure, the hydraulic accumulators are treated as pressure vessels and must be designed for the maximum operating pressure, taking into account the acceptance standards. For volume compensation in the hydraulic accumulator and the associated energy storage, the hydraulic fluid in the hydraulic accumulator is weighted or spring loaded or charged with gas. There is always a balance between the pressure of the pressure fluid and the weight of the spring or the back pressure generated by the gas. In most hydro plants hydropneumatic, so gas-loaded memory are used with separating element, which differs depending on the design of the separating element between bladder, piston and diaphragm accumulators.
  • the hydropneumatic accumulator mentioned have to fulfill a variety of tasks in a hydraulic system and, for example, in addition to the aforementioned energy storage for damping of mechanical shocks and pressure shock absorption in the hydraulic system to be involved.
  • hydraulic pumps such as positive displacement pumps
  • pulsations occur in the volume flow, these pulsations cause not only noise but also vibrations, which can lead to damage to the entire hydraulic system.
  • the aforementioned hydraulic, in particular positive displacement pumps are also used in the so-called.
  • Common rail technology in the field of diesel engines.
  • Newer developments of the third generation rely on the piezo technology for the injection systems for the diesel fuel.
  • the newly developed piezo inline injectors for the third common-rail generation (see VDI - News No. 33 of August 15, 2003) use piezo actuator modules that use coupler modules on switching valves and these in turn on a nozzle module of the fuel Injection system act, wherein the outstanding hydraulic speed of the system results from the high degree of integration of the inline injector, ie from the vicinity of the piezo package to the nozzle needle in the tip of the injector.
  • the moving masses of the new systems were reduced from 16g to 4g, whereby moving mass means the mass of the nozzle needle and the fuel filling the control chamber.
  • very high system pressures are necessary, which reach up to the order of 2200 bar.
  • the pertinent system pressure is from the said hydraulic pump, in particular positive displacement pump to build up with the described disadvantage of the occurring pressure and PulsationsstĂȘte. If these pressure surges are passed on to the injector system, this can be too critical System conditions lead to failure of the piezo-injector system and injection system. If one knows what is known (cf.
  • a further device for damping pressure pulsations in a fluid system in particular in a fuel system of an internal combustion engine, wherein the known device comprises a housing in which at least one working space is present. This is connected to the fluid system and is partially limited by at least one movable wall element in the form of a metal membrane, which is set stationary in the housing at the edge. This wall element is operatively connected to a first spring means and to be able to smooth pressure pulsations even with variable pressure in the fluid system, it is provided that the device comprises at least a second movable wall element, which limits a second working space and also consists of an edge fixed in the housing metal membrane.
  • the first spring device is arranged between the two wall elements in the form of the membranes and operatively connected to both. Further, a throttle device is provided, via which the second working space is connected to the fluid system.
  • a generic device for damping pressure surges in a fluid comprising a housing and a longitudinally movable piston against the biasing force of a spring accumulator in the housing, one piston cooperating with another piston, which is guided longitudinally displaceable in a connecting piece of the housing, wherein in operation of the device, the piston in each displacement position of the other piston exerts on this a compressive force and wherein the further piston is formed in the manner of a punch.
  • the two pistons are mechanically connected to each other, that is, a piston is an integral part of the other piston, to induce the damping of the guided in the housing first piston is permanently supported on the compression spring assembly. Due to the one-piece construction of the two mentioned pistons it is sufficient that for a captive for the other piston, the first piston can be supported on the front side of the fitting and insofar outside the continuous housing opening in case of need.
  • a comparable arrangement in the form of a single-piston solution with different piston diameters on opposite sides of the single piston arrangement is also due to the US 2003/183197 A1 demonstrated. As far as the damping of pressure surges at very high system pressures, these known solutions leave nothing to be desired.
  • the present invention seeks to provide a device for damping pressure surges available, with which it is possible, even at very high system pressures to 2200 bar occurring pressure surges, caused by a hydraulic pump, in particular diesel fuel pump, so To dampen and / or smooth out any harmful force discharges into a piezo injector system the common rail technology takes place.
  • This object is achieved by a device having the features of claim 1 in its entirety.
  • the one piston is larger in diameter by a multiple than the diameter of the other piston and it has been shown that an inhibiting driving operation with the piston can be achieved by the pertinent arrangement. Especially Verkantungsvortician the other piston in the connecting piece of the housing are avoided by its separate, independent guidance so.
  • the further piston is machined, in particular lapped, on the outer peripheral side such that a metallically dense gap is achieved at least between parts of the outer circumference and the further piston on the inner wall of the housing opening.
  • the further piston may be provided on the outer peripheral side with ring or lubrication grooves.
  • a leakage opening arranged in the housing opens into the fluid space between the pistons, then the diesel medium, which nevertheless penetrates the interior of the housing, can, in the form of a return bore for leak oil depressurized in the block towards the tank or leakage side.
  • At least one helical spring designed as a compression spring and / or a compressed gas as a spring accumulator.
  • the use of a pure compressed gas may entail the disadvantage that in view of the very high pressures under the influence of the compression of the first-mentioned piston, a liquefaction process of the gas in the housing region occurs. Accordingly, however, can be alternatively or additionally by using a compression spring as a spring memory, the system pressures safely dominate.
  • FIGURE shows in longitudinal section the device according to the invention for damping pressure surges with two different embodiments of cover parts.
  • the device shown in the figure is used to dampen pressure surges in a fluid, in particular in the form of diesel fuel, wherein the device has a cylindrical housing 10. Furthermore, the device has a against the biasing force of a spring accumulator 12 in the housing 10 longitudinally movable piston 14.
  • the pertinent piston 14 is formed in the manner of a cylindrical contact plate and along its outer periphery via a sliding and / or sealing ring 16 along the cylindrical Inner circumference 18 of the housing 10 out.
  • the piston 14 accordingly has on its opposite sides two substantially planar abutment surfaces 20,22 and the end-side guide of the spring accumulator 12, the piston 14 is provided on its side facing thereto with a cylindrical guide surface 22, the outer circumference also on the inner circumference 18 of Housing 10 is supported.
  • the piston 14 cooperates with a further piston 24, wherein the further piston 24 is guided in a connecting piece 26 of the housing 10 so as to be longitudinally movable. Further, as the illustration of the figure shows, the piston 14 acts in the housing with a compressive force on the further piston 24 in each operating travel position, also in its shown foremost end stop position during operation or use of the device.
  • the fitting 26 tapers towards the free end of the housing 10 and is provided on the outer peripheral side with a connecting thread 28, with which the housing 10 can be connected in the arrangement shown to a fluid system, for example to the diesel supply line for an injector system according to the common -Rail technology.
  • the housing 10 is located in a connecting line, which leads to a hydraulic pump, in particular positive displacement pump, for example in the form of a diesel fuel pump or the like.
  • a hydraulic pump in particular positive displacement pump, for example in the form of a diesel fuel pump or the like.
  • the pressure surges created during operation of the diesel fuel pump which can be considerable at system pressures of up to 2200 bar and more, are to be damped and smoothed with the device according to the invention, with high-frequency fluid pulses also being compensated.
  • the damping device according to the invention should be effective even at very high pressure amplitudes independently thereof in predeterminable limits.
  • Said connecting piece 26 merges into a length-reinforced base 30 of the housing 10 and said pistons 14, 24 and the spring accumulator 12 are oriented in their longitudinal direction on the longitudinal axis 32 of the housing 10 and connecting piece 26. Further, the piston 14 in diameter by a multiple larger than the diameter of the further piston 24, so that in view of the change in the diameter ratio, a very good impact force is introduced between further piston 24 and the first piston sixteenth
  • the further piston 24 is thus formed in the manner of a punch or plunger and guided over at least one captive 34 in the form of a locking ring in the through-housing opening 36 of the connecting piece 26.
  • the captive 34 may consist in particular of a retaining ring which closes the housing opening 36 to the outside at the front end and abuts the front end of the further piston 24 in its front boundary position at the supernatant thereof.
  • the length of the further piston 24 is dimensioned such that it maintains an axial distance from the captive 34 with a small clearance.
  • the piston 14 then exerts a pressure force on it in each displacement position of the further piston 24.
  • the further piston 24 on the outer circumference side is so finely worked, in particular lapped, that a metallically tight gap 38 is achieved at least between parts of the outer periphery of the further piston 24 and the inner wall of the housing opening 36.
  • the further piston 24 on the outer peripheral side ring or lubrication grooves 40 Such a labyrinth seal is achieved, which makes it more difficult for the diesel fuel the housing opening 36 into the space 42 within the housing 10 between the contact surface 20 and the bottom surface 44 facing the bottom 30 to penetrate.
  • a sealing system 48 is provided in the front, frontal region of the bottom 30, for example in the form of a conventional ring seal.
  • a compression spring in the form of a coil spring wherein the housing interior may also be additionally acted upon by a pressurized gas, for example in the form of a nitrogen gas.
  • the pertinent compression spring 12 extends between the piston 14 and a cover part 50, wherein the cover part 50 may be formed from a holding plate 52 which is held in the housing 10 via a securing means, in particular a securing ring 54.
  • a cover part 50 consists of a screw 56, the outer peripheral side via an external thread 58 of the housing 10 can be screwed onto this.
  • the device according to the invention it is ensured that any occurring leakage flows are safely controlled and due to the separate piston arrangement of the pistons 14 and 24 it is ensured that there is no tilting.
  • very high-frequency pressure surges acting on the punch-like further piston 24 can be in the same frequency impulsively pass on to the piston 16, which under the influence of the spring accumulator 12 and in response to the other piston 24 then performs the pulsation damping or PulsationsglĂ€ttung .
  • the system shown can be realized in particular on the housing side 10 of conventional steel materials in a cost effective manner and manufacturing technology.
  • the device according to the invention can generally be used where low volumes have to be level-regulated or displaced at high pressure. Due to the area ratios of the piston, the spring to be used can build smaller, since the required force is reduced accordingly.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Fluid-Damping Devices (AREA)
  • Actuator (AREA)

Abstract

A device for damping pressure surges in a fluid with a housing ( 10 ) and a piston ( 14 ) that can be longitudinally displaced inside the housing ( 10 ) against the pretensioning force of a spring energy store ( 12 ). The piston ( 14 ) interacts with another piston ( 24 ), which is guided in a connecting piece ( 26 ) of the housing ( 10 ) in a manner that enables it to be longitudinally displaced. During the operation of the device, the piston ( 14 ) exerts a pressure force onto the other piston ( 24 ) when the other piston is in any displacement position. Even pressure surges occurring with a high frequency can be reliably controlled in a functionally reliable manner.

Description

Die Erfindung betrifft eine Vorrichtung zum DĂ€mpfen von DruckstĂ¶ĂŸen in einem Fluid mit einem GehĂ€use und einem gegen die Vorspannkraft eines Federspeichers in dem GehĂ€use lĂ€ngsverfahrbaren Kolben gemĂ€ĂŸ der Merkmalsausgestaltung des Oberbegriffes des Patentanspruches 1.The invention relates to a device for damping pressure surges in a fluid with a housing and a longitudinally movable against the biasing force of a spring accumulator in the housing piston according to the feature configuration of the preamble of claim 1.

Zu den dahingehenden Vorrichtungen zĂ€hlen die sog. Hydrospeicher, wobei eine der Hauptaufgaben von Hydrospeichern es ist, bestimmte Volumen unter Druck stehender FlĂŒssigkeit einer Hydroanlage aufzunehmen und diese bei Bedarf wieder an die Anlage zurĂŒck zu geben. Da sich die FlĂŒssigkeit unter Druck befindet, werden die Hydrospeicher wie DruckbehĂ€lter behandelt und mĂŒssen fĂŒr den maximalen BetriebsĂŒberdruck unter BerĂŒcksichtigung der Abnahmestandards ausgelegt sein. Zum Volumenausgleich im Hydrospeicher und der damit verbundenen Energiespeicherung wird die DruckflĂŒssigkeit im Hydrospeicher gewichts- oder federbelastet oder mit Gas beaufschlagt. Dabei herrscht zwischen dem Druck der DruckflĂŒssigkeit und dem vom Gewicht der Feder oder dem vom Gas erzeugten Gegendruck stets ein Gleichgewicht. In den meisten Hydroanlagen werden hydropneumatische, also gasbeaufschlagte Speicher mit Trennelement eingesetzt, wobei man je nach Ausbildung des Trennelementes unterscheidet zwischen Blasen-, Kolben- und Membranspeichern.The devices in question include the so-called hydraulic accumulators, one of the main tasks of hydraulic accumulators being to take up certain volumes of pressurized fluid from a hydraulic system and, if necessary, to return them to the system. Since the fluid is under pressure, the hydraulic accumulators are treated as pressure vessels and must be designed for the maximum operating pressure, taking into account the acceptance standards. For volume compensation in the hydraulic accumulator and the associated energy storage, the hydraulic fluid in the hydraulic accumulator is weighted or spring loaded or charged with gas. There is always a balance between the pressure of the pressure fluid and the weight of the spring or the back pressure generated by the gas. In most hydro plants hydropneumatic, so gas-loaded memory are used with separating element, which differs depending on the design of the separating element between bladder, piston and diaphragm accumulators.

Die genannten hydropneumatischen Speicher haben in einer Hydroanlage verschiedenste Aufgaben zu erfĂŒllen und können beispielsweise neben der genannten Energiespeicherung auch zur DĂ€mpfung mechanischer StĂ¶ĂŸe sowie zur DruckstoßdĂ€mpfung im hydraulischen System mit beigezogen werden. Insbesondere bei Einsatz von hydraulischen Pumpen, wie VerdrĂ€ngerpumpen, entstehen Pulsationen im Volumenstrom, wobei diese Pulsationen neben LĂ€rm auch Vibrationen verursachen, was zu einer SchĂ€digung der gesamten Hydroanlage fĂŒhren kann.The hydropneumatic accumulator mentioned have to fulfill a variety of tasks in a hydraulic system and, for example, in addition to the aforementioned energy storage for damping of mechanical shocks and pressure shock absorption in the hydraulic system to be involved. In particular, when using hydraulic pumps, such as positive displacement pumps, pulsations occur in the volume flow, these pulsations cause not only noise but also vibrations, which can lead to damage to the entire hydraulic system.

Die genannten Hydro-, insbesondere VerdrĂ€ngerpumpen finden auch Anwendung in der sog. Common-Rail-Technik im Bereich von Dieselmotoren. Neuere Entwicklungen der dritten Generation setzen dabei fĂŒr die Einspritzsysteme fĂŒr den Dieselkraftstoff auf die Piezotechnik. Die dabei neu entwickelten Piezo-Inline-Injektoren fĂŒr die dritte Common-Rail-Generation (vgl. VDI - Nachrichten Nr. 33 vom 15. August 2003) verwenden Piezo-Aktormodule, die ĂŒber Kopplermodule auf Schaltventile und diese wiederum auf ein DĂŒsenmodul des Kraftstoff-Einspritzsystems einwirken, wobei sich die herausragende hydraulische Schnelligkeit des Systems aus dem hohen Integrationsgrad des Inline-Injektors ergibt, d.h. aus der NĂ€he des Piezo-Paketes zur DĂŒsennadel in der Spitze des Injektors. Im Vergleich zur vorangegangenen Generation wurde dabei bei den neuen Systemen die bewegte Masse von 16g auf 4g reduziert, wobei man unter bewegter Masse die Masse der DĂŒsennadel und des Kraftstoffes versteht, der den Steuerraum fĂŒllt. FĂŒr die dahingehende technische Auslegung sind sehr hohe SystemdrĂŒcke notwendig, die bis in die GrĂ¶ĂŸenordnung von 2200 bar heranreichen. Der dahingehende Systemdruck ist von der genannten Hydropumpe, insbesondere VerdrĂ€ngerpumpe, aufzubauen mit dem beschriebenen Nachteil der auftretenden Druck- und PulsationsstĂ¶ĂŸe. Werden die dahingehenden DruckstĂ¶ĂŸe an das Injektorsystem weitergegeben, kann dies zu kritischen SystemzustĂ€nden fĂŒhren und zu einem Ausfall der Piezo-lnjektoranlage nebst Einspritzsystem. Sofern man, was bekannt ist (vgl. DE 195 39 885 A1 ), im oben skizzierten Sinne ĂŒbliche Hydrospeicher mit Trennelement (Kolben) zur Pulsations- und DruckstoßdĂ€mpfung in das Diesel-Fluidsystem mit einbezieht, finden diese jedoch regelmĂ€ĂŸig ihre Grenzen im Hinblick auf die genannten hohen SystemdrĂŒcke bis 2200 bar.The aforementioned hydraulic, in particular positive displacement pumps are also used in the so-called. Common rail technology in the field of diesel engines. Newer developments of the third generation rely on the piezo technology for the injection systems for the diesel fuel. The newly developed piezo inline injectors for the third common-rail generation (see VDI - News No. 33 of August 15, 2003) use piezo actuator modules that use coupler modules on switching valves and these in turn on a nozzle module of the fuel Injection system act, wherein the outstanding hydraulic speed of the system results from the high degree of integration of the inline injector, ie from the vicinity of the piezo package to the nozzle needle in the tip of the injector. Compared to the previous generation, the moving masses of the new systems were reduced from 16g to 4g, whereby moving mass means the mass of the nozzle needle and the fuel filling the control chamber. For the pertinent technical design very high system pressures are necessary, which reach up to the order of 2200 bar. The pertinent system pressure is from the said hydraulic pump, in particular positive displacement pump to build up with the described disadvantage of the occurring pressure and PulsationsstĂ¶ĂŸe. If these pressure surges are passed on to the injector system, this can be too critical System conditions lead to failure of the piezo-injector system and injection system. If one knows what is known (cf. DE 195 39 885 A1 ), in the sense outlined above common hydraulic accumulator with separating element (piston) for Pulsations- and pressure shock absorption in the diesel fluid system includes, but they regularly find their limits in terms of the said high system pressures up to 2200 bar.

Durch die DE 101 48 220 A1 ist eine weitere Vorrichtung zum DĂ€mpfen von Druckpulsationen in einem Fluidsystem bekannt, insbesondere in einem Kraftstoffsystem einer Brennkraftmaschine, wobei die bekannte Vorrichtung ein GehĂ€use umfaßt, in dem mindestens ein Arbeitsraum vorhanden ist. Dieser ist mit dem Fluidsystem verbunden und wird bereichsweise von mindestens einem beweglichen Wandelement in Form einer Metallmembran begrenzt, die randseitig im GehĂ€use stationĂ€r festgelegt ist. Dieses Wandelement ist mit einer ersten Federeinrichtung wirkverbunden und um Druckpulsationen auch bei variablem Druck im Fluidsystem glĂ€tten zu können, ist vorgesehen, dass die Vorrichtung mindestens ein zweites bewegliches Wandelement umfaßt, welches einen zweiten Arbeitsraum begrenzt und gleichfalls aus einer randseitig im GehĂ€use festgelegen Metallmembran besteht. Die erste Federeinrichtung ist zwischen den beiden Wandelementen in Form der Membranen angeordnet und mit beiden wirkverbunden. Ferner ist eine Drosseleinrichtung vorgesehen, ĂŒber welche der zweite Arbeitsraum mit dem Fluidsystem verbunden ist. Mit der bekannten Lösung lassen sich zwar Druckpulsationen in einem Fluidsystem bei unterschiedlichen Druckniveaus zuverlĂ€ssig und gut glĂ€tten. Aufgrund der festen Einspannung der Wandelemente (Membrane) ist aber deren Bewegbarkeit eingeschrĂ€nkt, so dass bei hohen DrĂŒcken und entsprechend großen Pulsations- und DruckstĂ¶ĂŸen ein funktionssicherer Betrieb gefĂ€hrdet sein kann. Durch die US 5 456 233 A ist bei einem Kraftstoff-Einspritzsystem mit einer Hochdruckpumpe fĂŒr eine Brennkraftmaschine eine gattungsgemĂ€ĂŸe Vorrichtung zum DĂ€mpfen von DruckstĂ¶ĂŸen in einem Fluid bekannt, mit einem GehĂ€use und einem gegen die Vorspannkraft eines Federspeichers in dem GehĂ€use lĂ€ngsverfahrbaren Kolben, wobei der eine Kolben mit einem weiteren Kolben zusammenwirkt, der in einem AnschlußstĂŒck des GehĂ€uses lĂ€ngsverfahrbar gefĂŒhrt ist, wobei beim Betrieb der Vorrichtung der Kolben in jeder Verfahrstellung des weiteren Kolbens auf diesen eine Druckkraft ausĂŒbt und wobei der weitere Kolben in der Art eines Stempels ausgebildet ist. Bei der bekannten Lösung sind die beiden Kolben mechanisch miteinander verbunden, d.h. der eine Kolben ist einstĂŒckiger Bestandteil des weiteren Kolbens, wobei zum HerbeifĂŒhren der DĂ€mpfung der im GehĂ€use gefĂŒhrte erste Kolben sich an der Druckfederanordnung permanent abstĂŒtzt. Aufgrund der einstĂŒckigen Ausbildung der beiden genannten Kolben genĂŒgt es, dass fĂŒr eine Verliersicherung fĂŒr den weiteren Kolben der erste Kolben sich an der Stirnseite des AnschlußstĂŒckes und insoweit außerhalb der durchgehenden GehĂ€useöffnung im Bedarfsfall abstĂŒtzen kann. Eine vergleichbare Anordnung in Form einer Einkolbenlösung mit unterschiedlichen Kolbendurchmessern auf gegenĂŒberliegenden Seiten der Einkolbenanordnung ist auch durch die US 2003/183197 A1 aufgezeigt. Was das DĂ€mpfen von DruckstĂ¶ĂŸen bei sehr hohen SystemdrĂŒcken anbelangt, lassen diese bekannten Lösungen noch WĂŒnsche offen.By the DE 101 48 220 A1 a further device for damping pressure pulsations in a fluid system is known, in particular in a fuel system of an internal combustion engine, wherein the known device comprises a housing in which at least one working space is present. This is connected to the fluid system and is partially limited by at least one movable wall element in the form of a metal membrane, which is set stationary in the housing at the edge. This wall element is operatively connected to a first spring means and to be able to smooth pressure pulsations even with variable pressure in the fluid system, it is provided that the device comprises at least a second movable wall element, which limits a second working space and also consists of an edge fixed in the housing metal membrane. The first spring device is arranged between the two wall elements in the form of the membranes and operatively connected to both. Further, a throttle device is provided, via which the second working space is connected to the fluid system. Although pressure pulsations in a fluid system can be smoothed reliably and well at different pressure levels with the known solution. Due to the fixed restraint of the wall elements (membrane) but their mobility is limited, so that at high pressures and correspondingly large pulsation and pressure surges a reliable operation can be compromised. By the US 5 456 233 A in a fuel injection system with a high-pressure pump for an internal combustion engine, a generic device for damping pressure surges in a fluid is known, comprising a housing and a longitudinally movable piston against the biasing force of a spring accumulator in the housing, one piston cooperating with another piston, which is guided longitudinally displaceable in a connecting piece of the housing, wherein in operation of the device, the piston in each displacement position of the other piston exerts on this a compressive force and wherein the further piston is formed in the manner of a punch. In the known solution, the two pistons are mechanically connected to each other, that is, a piston is an integral part of the other piston, to induce the damping of the guided in the housing first piston is permanently supported on the compression spring assembly. Due to the one-piece construction of the two mentioned pistons it is sufficient that for a captive for the other piston, the first piston can be supported on the front side of the fitting and insofar outside the continuous housing opening in case of need. A comparable arrangement in the form of a single-piston solution with different piston diameters on opposite sides of the single piston arrangement is also due to the US 2003/183197 A1 demonstrated. As far as the damping of pressure surges at very high system pressures, these known solutions leave nothing to be desired.

Ausgehend von diesem Stand der Technik liegt der Erfindung die Aufgabe zugrunde, eine Vorrichtung zum DĂ€mpfen von DruckstĂ¶ĂŸen zur VerfĂŒgung zu stellen, mit der es möglich ist, auch bei sehr hohen SystemdrĂŒcken bis 2200 bar auftretende DruckstĂ¶ĂŸe, hervorgerufen durch eine Hydropumpe, insbesondere Dieselkraftstoffpumpe, derart zu dĂ€mpfen und/oder zu glĂ€tten, dass keine schĂ€dlichen Krafteinleitungen in ein Piezo-Injektorsystem der Common-Rail-Technik erfolgt. Eine dahingehende Aufgabe löst eine Vorrichtung mit den Merkmalen des Patentanspruches 1 in seiner Gesamtheit.Based on this prior art, the present invention seeks to provide a device for damping pressure surges available, with which it is possible, even at very high system pressures to 2200 bar occurring pressure surges, caused by a hydraulic pump, in particular diesel fuel pump, so To dampen and / or smooth out any harmful force discharges into a piezo injector system the common rail technology takes place. This object is achieved by a device having the features of claim 1 in its entirety.

Dadurch, dass gemĂ€ĂŸ dem kennzeichnenden Teil des Patentanspruches 1 die beiden genannten Kolben mechanisch voneinander entkoppelt sind und dass die durchgehende GehĂ€useöffnung des AnschlußstĂŒckes die Verliersicherung aufweist, lassen sich in funktionssicherer Weise auch sehr hochfrequente DruckstĂ¶ĂŸe im Dieselkraftstoffsystem sicher beherrschen, auch wenn bedingt durch die Hydropumpe in Form der Dieselkraftstoffpumpe sehr hohe SystemdrĂŒcke von bis zu 2200 bar und mehr erzeugt sind. Durch die mechanische Entkopplung der beiden genannten Kolben und die permanente Druckkrafteinleitung des einen Kolbens auf den weiteren Kolben ist sichergestellt, dass die eingeleiteten DruckstĂ¶ĂŸe sicher aufgefangen und beherrscht werden können und insbesondere ist durch die Entkopplung der Kolben sichergestellt, dass etwaige Undichtigkeiten mit einhergehenden Leckageströmen gering gehalten sind oder dergestalt beherrscht werden, dass FunktionsausfĂ€lle im Gesamtsystem vermieden sind, wozu auch mit beitrĂ€gt, dass fĂŒr den weiteren Kolben eine eigenstĂ€ndige Verliersicherung in der durchgehenden GehĂ€useöffnung des AnschlußstĂŒckes vorgesehen ist. Auf diese Art und Weise ist die freie Verfahrbarkeit der jeweiligen Kolben zwischen vorgebbaren Verfahrschranken in der GehĂ€useanordnung erreicht.The fact that according to the characterizing part of claim 1, the two said pistons are mechanically decoupled from each other and that the continuous housing opening of the connector has the captive, can be reliably function well controlled even high-frequency pressure surges in the diesel fuel system, even if due to the hydraulic pump in Form of diesel fuel pump very high system pressures of up to 2200 bar and more are generated. The mechanical decoupling of the two mentioned piston and the permanent pressure force introduction of a piston on the other piston ensures that the introduced pressure surges can be safely collected and controlled and in particular is ensured by the decoupling of the piston that any leaks with accompanying leakage currents kept low are or are dominated in such a way that functional failures are avoided in the overall system, which also contributes to the fact that for the other piston an independent captive is provided in the through-housing opening of the connector. In this way, the free movement of the respective piston between predeterminable Verfahrschranken is achieved in the housing assembly.

Vorzugsweise ist dabei vorgesehen, dass der eine Kolben im Durchmesser um ein Mehrfaches grĂ¶ĂŸer ist als der Durchmesser des weiteren Kolbens und es hat sich gezeigt, dass durch die dahingehende Anordnung ein hemmfreier Ansteuervorgang mit den Kolben erreichbar ist. Insbesondere VerkantungsvorgĂ€nge des weiteren Kolbens im AnschlußstĂŒck des GehĂ€uses sind durch seine getrennte, eigenstĂ€ndige FĂŒhrung derart vermieden.Preferably, it is provided that the one piston is larger in diameter by a multiple than the diameter of the other piston and it has been shown that an inhibiting driving operation with the piston can be achieved by the pertinent arrangement. Especially VerkantungsvorgĂ€nge the other piston in the connecting piece of the housing are avoided by its separate, independent guidance so.

Bei einer weiteren bevorzugten AusfĂŒhrungsform der erfindungsgemĂ€ĂŸen Vorrichtung ist der weitere Kolben außenumfangsseitig derart feinstbearbeitet, insbesondere gelĂ€ppt, dass ein metallisch dichter Spalt zumindest zwischen Teilen des Außenumfanges und des weiteren Kolbens an der Innenwandung der GehĂ€useöffnung erreicht ist. In weiterer Ausgestaltung des genannten Dichtsystems kann der weitere Kolben außenumfangsseitig mit Ring- oder Schmiernuten versehen sein. Hierdurch wird trotz der hohen DrĂŒcke von bis zu 2200 bar und mehr im Diesel-Fluidsystem eine sichere Abdichtung des weiteren Kolbens gegenĂŒber dem GehĂ€useinneren mit dem ersten Kolben erreicht und insbesondere bei Einsatz der Ring- oder Schmiernuten am Außenumfang des weiteren Kolbens kann sich dergestalt eine Fluiddichtung aufbauen, die dem Fluideintritt in den metallischen Spalt entgegenwirkt.In a further preferred embodiment of the device according to the invention, the further piston is machined, in particular lapped, on the outer peripheral side such that a metallically dense gap is achieved at least between parts of the outer circumference and the further piston on the inner wall of the housing opening. In a further embodiment of said sealing system, the further piston may be provided on the outer peripheral side with ring or lubrication grooves. In this way, despite the high pressures of up to 2200 bar and more in the diesel fluid system, a secure sealing of the other piston relative to the housing interior achieved with the first piston and in particular when using the ring or lubrication grooves on the outer periphery of the other piston can thus a fluid seal build up, which counteracts the fluid entry into the metallic gap.

Sofern bei einer bevorzugten AusfĂŒhrungsform der erfindungsgemĂ€ĂŸen Vorrichtung in den Fluidraum zwischen den Kolben eine im GehĂ€use angeordnete Leckageöffnung mĂŒndet, kann dergestalt in der Art einer RĂŒcklaufbohrung fĂŒr Lecköl das dennoch in das GehĂ€useinnere eindringende Dieselmedium drucklos im Block in Richtung auf die Tank- oder Leckageseite abgegeben werden.If, in a preferred embodiment of the device according to the invention, a leakage opening arranged in the housing opens into the fluid space between the pistons, then the diesel medium, which nevertheless penetrates the interior of the housing, can, in the form of a return bore for leak oil depressurized in the block towards the tank or leakage side.

Im Hinblick auf die angesprochenen sehr hohen DrĂŒcke hat es sich als vorteilhaft erwiesen, als Federspeicher mindestens eine als Druckfeder ausgebildete Schraubenfeder und/oder ein Druckgas vorzusehen. Der Einsatz eines reinen Druckgases bringt gegebenenfalls den Nachteil mit sich, dass im Hinblick auf die sehr hohen DrĂŒcke es unter dem Einfluß der Kompression des erstgenannten Kolbens zu einem VerflĂŒssigungsvorgang des Gases in dem GehĂ€usebereich kommt. DemgemĂ€ĂŸ lassen sich aber alternativ oder zusĂ€tzlich durch Einsatz einer Druckfeder als Federspeicher die genannten SystemdrĂŒcke sicher beherrschen.In view of the above-mentioned very high pressures, it has proved to be advantageous to provide at least one helical spring designed as a compression spring and / or a compressed gas as a spring accumulator. The use of a pure compressed gas may entail the disadvantage that in view of the very high pressures under the influence of the compression of the first-mentioned piston, a liquefaction process of the gas in the housing region occurs. Accordingly, however, can be alternatively or additionally by using a compression spring as a spring memory, the system pressures safely dominate.

Weitere vorteilhafte AusfĂŒhrungsformen der erfindungsgemĂ€ĂŸen Vorrichtung sind Gegenstand der sonstigen UnteransprĂŒche.Further advantageous embodiments of the device according to the invention are the subject of the other dependent claims.

Im folgenden wird die erfindungsgemĂ€ĂŸe Vorrichtung anhand eines AusfĂŒhrungsbeispiels nach der Zeichnung nĂ€her erlĂ€utert. Dabei zeigt in prinzipieller und nicht maßstĂ€blicher Darstellung die einzige Figur im LĂ€ngsschnitt die erfindungsgemĂ€ĂŸe Vorrichtung zum DĂ€mpfen von DruckstĂ¶ĂŸen mit zwei verschiedenen AusfĂŒhrungsformen an Deckelteilen.In the following the device according to the invention will be explained in more detail with reference to an embodiment of the drawing. In a schematic and not to scale representation, the single FIGURE shows in longitudinal section the device according to the invention for damping pressure surges with two different embodiments of cover parts.

Die in der Figur gezeigte Vorrichtung dient dem DĂ€mpfen von DruckstĂ¶ĂŸen in einem Fluid, insbesondere in Form von Dieselkraftstoff, wobei die Vorrichtung ein zylindrisches GehĂ€use 10 aufweist. Ferner weist die Vorrichtung einen gegen die Vorspannkraft eines Federspeichers 12 in dem GehĂ€use 10 lĂ€ngsverfahrbaren Kolben 14 auf. Der dahingehende Kolben 14 ist in der Art einer zylindrischen Anlageplatte ausgebildet und entlang seines Außenumfanges ĂŒber einen Gleit- und/oder Dichtring 16 lĂ€ngs des zylindrischen Innenumfanges 18 des GehĂ€uses 10 gefĂŒhrt. Der Kolben 14 weist demgemĂ€ĂŸ an seinen einander gegenĂŒberliegenden Seiten zwei im wesentlichen plane AnlageflĂ€chen 20,22 auf und zur endseitigen FĂŒhrung des Federspeichers 12 ist der Kolben 14 an seiner dahingehend gerichteten Seite mit einer zylindrischen FĂŒhrungsflĂ€che 22 versehen, die sich außenumfangsseitig gleichfalls am Innenumfang 18 des GehĂ€uses 10 abstĂŒtzt.The device shown in the figure is used to dampen pressure surges in a fluid, in particular in the form of diesel fuel, wherein the device has a cylindrical housing 10. Furthermore, the device has a against the biasing force of a spring accumulator 12 in the housing 10 longitudinally movable piston 14. The pertinent piston 14 is formed in the manner of a cylindrical contact plate and along its outer periphery via a sliding and / or sealing ring 16 along the cylindrical Inner circumference 18 of the housing 10 out. The piston 14 accordingly has on its opposite sides two substantially planar abutment surfaces 20,22 and the end-side guide of the spring accumulator 12, the piston 14 is provided on its side facing thereto with a cylindrical guide surface 22, the outer circumference also on the inner circumference 18 of Housing 10 is supported.

Der Kolben 14 wirkt mit einem weiteren Kolben 24 zusammen, wobei der dahingehend weitere Kolben 24 in einem AnschlußstĂŒck 26 des GehĂ€uses 10 lĂ€ngsverfahrbar gefĂŒhrt ist. Ferner wirkt, wie die Darstellung nach der Figur zeigt, der Kolben 14 in jeder Betriebs-Verfahrstellung, auch in seiner gezeigten vordersten Endanschlagstellung beim Betrieb oder Gebrauch der Vorrichtung, im GehĂ€use mit einer Druckkraft auf den weiteren Kolben 24 ein. Das AnschlußstĂŒck 26 verjĂŒngt sich zum freien Ende des GehĂ€use 10 hin absatzartig und ist außenumfangsseitig mit einem Anschlußgewinde 28 versehen, mit dem sich das GehĂ€use 10 in der gezeigten Anordnung an ein Fluidsystem anschließen lĂ€ĂŸt, beispielsweise an die Diesel-Versorgungsleitung fĂŒr ein Injektorsystem nach der Common-Rail-Technik. Das GehĂ€use 10 befindet sich dabei in einer Anschlußleitung, die zu einer Hydropumpe, insbesondere VerdrĂ€ngerpumpe, fĂŒhrt, beispielsweise in Form einer Dieselkraftstoffpumpe oder dergleichen. Die beim Betrieb der Dieselkraftstoffpumpe entstehenden DruckstĂ¶ĂŸe, die bei SystemdrĂŒcken von bis zu 2200 bar und mehr erheblich sein können, sollen mit der erfindungsgemĂ€ĂŸen Vorrichtung gedĂ€mpft und geglĂ€ttet werden, wobei auch hochfrequente FluidstĂ¶ĂŸe ausgeglichen werden sollen. Ferner soll die erfindungsgemĂ€ĂŸe DĂ€mpfungsvorrichtung auch bei sehr hohen Druckamplituden unabhĂ€ngig hiervon in vorgebbaren Grenzbereichen wirksam sein.The piston 14 cooperates with a further piston 24, wherein the further piston 24 is guided in a connecting piece 26 of the housing 10 so as to be longitudinally movable. Further, as the illustration of the figure shows, the piston 14 acts in the housing with a compressive force on the further piston 24 in each operating travel position, also in its shown foremost end stop position during operation or use of the device. The fitting 26 tapers towards the free end of the housing 10 and is provided on the outer peripheral side with a connecting thread 28, with which the housing 10 can be connected in the arrangement shown to a fluid system, for example to the diesel supply line for an injector system according to the common -Rail technology. The housing 10 is located in a connecting line, which leads to a hydraulic pump, in particular positive displacement pump, for example in the form of a diesel fuel pump or the like. The pressure surges created during operation of the diesel fuel pump, which can be considerable at system pressures of up to 2200 bar and more, are to be damped and smoothed with the device according to the invention, with high-frequency fluid pulses also being compensated. Furthermore, the damping device according to the invention should be effective even at very high pressure amplitudes independently thereof in predeterminable limits.

Das genannte AnschlußstĂŒck 26 geht in einen in der LĂ€nge verstĂ€rkten Boden 30 des GehĂ€uses 10 ĂŒber und die genannten Kolben 14,24 sowie der Federspeicher 12 orientieren sich in ihrer LĂ€ngsausrichtung an der LĂ€ngsachse 32 von GehĂ€use 10 und AnschlußstĂŒck 26. Des weiteren ist der Kolben 14 im Durchmesser um ein Mehrfaches grĂ¶ĂŸer als der Durchmesser des weiteren Kolbens 24, so dass im Hinblick auf die Änderung des DurchmesserverhĂ€ltnisses eine sehr gute Stoßkrafteinleitung erfolgt zwischen weiterem Kolben 24 und erstem Kolben 16.Said connecting piece 26 merges into a length-reinforced base 30 of the housing 10 and said pistons 14, 24 and the spring accumulator 12 are oriented in their longitudinal direction on the longitudinal axis 32 of the housing 10 and connecting piece 26. Further, the piston 14 in diameter by a multiple larger than the diameter of the further piston 24, so that in view of the change in the diameter ratio, a very good impact force is introduced between further piston 24 and the first piston sixteenth

Der weitere Kolben 24 ist mithin in der Art eines Stempels oder StĂ¶ĂŸels ausgebildet und ĂŒber mindestens eine Verliersicherung 34 in Form eines Sicherungsringes in der durchgehenden GehĂ€useöffnung 36 des AnschlußstĂŒckes 26 gefĂŒhrt. Die Verliersicherung 34 kann dabei insbesondere aus einem Sicherungsring bestehen, der am vorderen Ende die GehĂ€useöffnung 36 nach außen hin abschließt und an dessen Überstand das vordere Ende des weiteren Kolbens 24 in seiner vorderen Begrenzungslage anstĂ¶ĂŸt. Im unbetĂ€tigten Zustand ist die LĂ€nge des weiteren Kolbens 24 derart bemessen, dass dieser mit einem geringen Spiel einen axialen Abstand zu der Verliersicherung 34 einhĂ€lt. Sobald jedoch ĂŒber den Kraftstoff ein vorgebbares Druckniveau aufgebaut ist, ist das Spiel beseitigt und im dahingehenden Betriebs- oder Gebrauchszustand der Vorrichtung ĂŒbt dann der Kolben 14 in jeder Verfahrstellung des weiteren Kolbens 24 auf diesen eine Druckkraft aus. Um eine gute Abdichtung zu erreichen, ist der weitere Kolben 24 außenumfangsseitig derart feinstbearbeitet, insbesondere gelĂ€ppt, dass ein metallisch dichter Spalt 38 zumindest zwischen Teilen des Außenumfanges des weiteren Kolbens 24 und der Innenwandung der GehĂ€useöffnung 36 erreicht ist. Zur weiteren Verbesserung des Dichtsystems weist der weitere Kolben 24 außenumfangsseitig Ring- oder Schmiernuten 40 auf. Derartig ist eine Labyrinthdichtung erreicht, die es dem Dieselkraftstoff erschwert, ĂŒber die GehĂ€useöffnung 36 in den Zwischenraum 42 innerhalb des GehĂ€uses 10 zwischen AnlageflĂ€che 20 und der ihr zugewandten BodenflĂ€che 44 des Bodens 30 einzudringen.The further piston 24 is thus formed in the manner of a punch or plunger and guided over at least one captive 34 in the form of a locking ring in the through-housing opening 36 of the connecting piece 26. The captive 34 may consist in particular of a retaining ring which closes the housing opening 36 to the outside at the front end and abuts the front end of the further piston 24 in its front boundary position at the supernatant thereof. In the unactuated state, the length of the further piston 24 is dimensioned such that it maintains an axial distance from the captive 34 with a small clearance. However, as soon as a predeterminable pressure level is built up over the fuel, the play is eliminated and in the pertinent operating or operating state of the device, the piston 14 then exerts a pressure force on it in each displacement position of the further piston 24. In order to achieve a good seal, the further piston 24 on the outer circumference side is so finely worked, in particular lapped, that a metallically tight gap 38 is achieved at least between parts of the outer periphery of the further piston 24 and the inner wall of the housing opening 36. To further improve the sealing system, the further piston 24 on the outer peripheral side ring or lubrication grooves 40. Such a labyrinth seal is achieved, which makes it more difficult for the diesel fuel the housing opening 36 into the space 42 within the housing 10 between the contact surface 20 and the bottom surface 44 facing the bottom 30 to penetrate.

In den genannten Fluid- oder Zwischenraum 42 zwischen den Kolben 14,24 mĂŒndet eine im GehĂ€use 10 angeordnete Leckageöffnung 46 in der Art einer Bohrung und dergestalt kann ein bewußt vorgesehener Spalt- oder Leckagestrom ĂŒber das Dichtsystem in Form der Ring- oder Schmiernuten 40, den metallischen Spalt 38 sowie den Zwischenraum 42 ĂŒber die Leckageöffnung 46 auf die drucklose Leck- oder Tankseite des Gesamtsystems abgefĂŒhrt werden. Als weiteres Dichtsystem ist im vorderen, stirnseitigen Bereich des Bodens 30 ein Dichtsystem 48 vorgesehen, beispielsweise in Form einer ĂŒblichen Ringdichtung. Bei eingeschraubtem GehĂ€use 10 ĂŒber das AnschlußstĂŒck 26 mit seinem Anschlußgewinde 28 lĂ€ĂŸt sich dergestalt eine Abdichtung, insbesondere in Form der Leckageöffnung 46, gegenĂŒber dem gesamt hydraulischen- oder Fluidsystem (Dieselleitungsnetz) erreichen.In the said fluid or space 42 between the pistons 14,24 opens a arranged in the housing 10 leakage opening 46 in the manner of a bore and such a deliberately provided gap or leakage flow through the sealing system in the form of annular or lubrication grooves 40, the metallic gap 38 and the gap 42 are discharged via the leakage opening 46 to the non-pressurized leak or tank side of the overall system. As a further sealing system a sealing system 48 is provided in the front, frontal region of the bottom 30, for example in the form of a conventional ring seal. When the housing 10 is screwed in via the connecting piece 26 with its connecting thread 28, a seal, in particular in the form of the leakage opening 46, can be achieved in relation to the entire hydraulic or fluid system (diesel pipeline network).

Als Federspeicher 12 dient im vorliegenden Fall eine Druckfeder in Form einer Schraubenfeder, wobei das GehĂ€useinnere auch zusĂ€tzlich noch mit einem Druckgas, beispielsweise in Form eines Stickstoffgases, beaufschlagt sein kann. Die dahingehende Druckfeder 12 erstreckt sich zwischen dem Kolben 14 und einem Deckelteil 50, wobei das Deckelteil 50 aus einer Halteplatte 52 gebildet sein kann, die ĂŒber ein Sicherungsmittel, insbesondere einen Sicherungsring 54, im GehĂ€use 10 gehalten ist. Eine alternative AusfĂŒhrungsform ist in der Figur in einer quadratischen Umrahmung wiedergegeben und im dahingehenden Fall besteht das Deckelteil 50 aus einem Schraubdeckel 56, der außenumfangsseitig ĂŒber ein Außengewinde 58 des GehĂ€uses 10 auf dieses aufschraubbar ist.As a spring accumulator 12 is used in the present case, a compression spring in the form of a coil spring, wherein the housing interior may also be additionally acted upon by a pressurized gas, for example in the form of a nitrogen gas. The pertinent compression spring 12 extends between the piston 14 and a cover part 50, wherein the cover part 50 may be formed from a holding plate 52 which is held in the housing 10 via a securing means, in particular a securing ring 54. An alternative embodiment is shown in the figure in a square frame and in this case, the cover part 50 consists of a screw 56, the outer peripheral side via an external thread 58 of the housing 10 can be screwed onto this.

Mit der erfindungsgemĂ€ĂŸen Vorrichtung ist sichergestellt, dass etwaig auftretende Leckageströme sicher beherrscht werden und aufgrund der getrennten Kolbenanordnung der Kolben 14 und 24 ist sichergestellt, dass es nicht zu Verkantungen kommt. Insbesondere sehr hochfrequente DruckstĂ¶ĂŸe, die auf den stempelartigen weiteren Kolben 24 einwirken, lassen sich dergestalt in derselben Frequenz stoßartig an den Kolben 16 weitergeben, der unter dem Einfluß des Federspeichers 12 und unter RĂŒckwirkung auf den weiteren Kolben 24 dann derart die PulsationsdĂ€mpfung bzw. PulsationsglĂ€ttung vornimmt. Das gezeigte System lĂ€ĂŸt sich insbesondere auf der GehĂ€useseite 10 aus ĂŒblichen Stahlwerkstoffen in kostengĂŒnstiger Weise und fertigungstechnisch einfach realisieren. Die erfindungsgemĂ€ĂŸe Vorrichtung kann generell dort eingesetzt werden, wo geringe Volumen bei hohem Druck niveaugedĂ€mpft bzw. verschoben werden mĂŒssen. Durch die FlĂ€chenverhĂ€ltnisse der Kolben kann die einzusetzende Feder kleiner aufbauen, da die erforderliche Kraft entsprechend reduziert wird.With the device according to the invention it is ensured that any occurring leakage flows are safely controlled and due to the separate piston arrangement of the pistons 14 and 24 it is ensured that there is no tilting. In particular, very high-frequency pressure surges acting on the punch-like further piston 24 can be in the same frequency impulsively pass on to the piston 16, which under the influence of the spring accumulator 12 and in response to the other piston 24 then performs the pulsation damping or PulsationsglĂ€ttung , The system shown can be realized in particular on the housing side 10 of conventional steel materials in a cost effective manner and manufacturing technology. The device according to the invention can generally be used where low volumes have to be level-regulated or displaced at high pressure. Due to the area ratios of the piston, the spring to be used can build smaller, since the required force is reduced accordingly.

Claims (9)

  1. An apparatus for damping pressure surges in a fluid comprising a housing (10) and a piston (14) that can be displaced longitudinally within the housing (10) against the pretensioning force of a spring accumulator (12), the piston (14) interacting with a further piston (24) which is guided with longitudinal displacement within a connecting piece (26) of the housing (10), during operation of the apparatus the piston (14) exerting a compressive force upon the further piston (24) in every displacement position of the latter which interacts with a securing device, the further piston (24) being in the form a stamp, and the further piston being guided within a continuous housing opening (36) of the connecting piece (26), characterised in that the two aforementioned pistons (14, 24) are decoupled from one another mechanically and that the continuous housing opening (36) of the connecting piece (26) has the securing device (34).
  2. The apparatus according to Claim 1, characterised in that the diameter of the piston (14) is greater by one multiple than the diameter of the further piston (24).
  3. The apparatus according to Claim 1 or 2, characterised in that the further piston (24) is finely machined on the outer circumference, and in particular is lapped such that a metallically tight gap (38) is achieved at least between parts of the outer circumference of the further piston (24) and the inner wall of the housing opening (36).
  4. The apparatus according to any of Claims 1 to 3, characterised in that the further piston (24) is provided on the outer circumference with annular or lubrication grooves (40).
  5. The apparatus according to any of Claims 1 to 4, characterised in that a leakage opening (46) disposed in the housing (10) opens out into the fluid space (42) between the pistons (14, 24).
  6. The apparatus according to any of Claims 1 to 5, characterised in that at least one helical spring in the form of a compression spring and/or a compressed gas acts as a spring accumulator (12).
  7. The apparatus according to Claim 6, characterised in that the compression spring (12) extends between the piston (14) and a cover part (50) within the housing.
  8. The apparatus according to any of Claims 1 to 7, characterised in that the cover part (50) is formed from a holding plate (52) which is held in the housing (10) by a securing means, in particular a retaining ring (54), or that the cover part (50) consists of a screw-on cover (56) which can be screwed onto the housing (10) by means of an external thread (58) of the latter on the outer circumference.
  9. The apparatus according to any of Claims 1 to 8, characterised in that the connecting piece (26) of the housing (10) in which the further piston (24) is guided has a reduced outer diameter in relation to the outer diameter of the housing (10).
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JP2007511695A (en) 2007-05-10
EP1685323A1 (en) 2006-08-02
ATE472053T1 (en) 2010-07-15
DE502004011318D1 (en) 2010-08-05
US7308910B2 (en) 2007-12-18
WO2005052348A1 (en) 2005-06-09
DE10350941A1 (en) 2005-06-02

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