EP0010768B1 - Hydraulic backlash adjuster - Google Patents

Hydraulic backlash adjuster Download PDF

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Publication number
EP0010768B1
EP0010768B1 EP79104279A EP79104279A EP0010768B1 EP 0010768 B1 EP0010768 B1 EP 0010768B1 EP 79104279 A EP79104279 A EP 79104279A EP 79104279 A EP79104279 A EP 79104279A EP 0010768 B1 EP0010768 B1 EP 0010768B1
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EP
European Patent Office
Prior art keywords
air
hydraulic fluid
hydraulic
cylinder
piston
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
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EP79104279A
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German (de)
French (fr)
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EP0010768A1 (en
Inventor
Gerhard Ing. Grad Turlach
Diethard Ing. Grad Michel
Günter Hetterscheidt
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Kamax Werke Rudolf Kellermann GmbH and Co KG
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Kamax Werke Rudolf Kellermann GmbH and Co KG
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Priority to AT79104279T priority Critical patent/ATE980T1/en
Publication of EP0010768A1 publication Critical patent/EP0010768A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/20—Adjusting or compensating clearance
    • F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
    • F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
    • F01L1/245—Hydraulic tappets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/20—Adjusting or compensating clearance
    • F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
    • F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
    • F01L1/245—Hydraulic tappets
    • F01L1/25—Hydraulic tappets between cam and valve stem

Definitions

  • the invention relates to a hydraulic lash adjuster with a piston displaceably guided in a cylinder and a working space formed between the piston and the cylinder and a storage space arranged in the piston and / or in the cylinder and sealed to the outside in a pressure-tight manner, which is partly filled with an air cushion and partly with hydraulic fluid and in which an element preventing the foaming of air in hydraulic fluid is provided, the storage space being connected to the working space via a channel having a check valve and the working space being connected to the storage space via a throttle gap.
  • Such hydraulic lash adjusters are used in particular for the control of the valves of internal combustion engines.
  • US-A-2694388 and DE-A-2911550 show such a hydraulic lash adjuster, in which the storage space is sealed pressure-tight from the atmosphere.
  • An air cushion is arranged and provided in the storage space, which is separated from the hydraulic fluid in the storage space by a membrane, a balloon body or the like forming a chamber for the air cushion.
  • the membrane is designed to be liquid and airtight, so that the air cushion is kept effectively separate from the hydraulic fluid in the storage space at all times.
  • the enclosed air cushion is suitable for briefly absorbing pressure peaks that occur and releasing them back to the hydraulic fluid in the reservoir if the work space needs to be refilled from the reservoir with the check valve open.
  • the hydraulic fluid itself still contains a certain amount of air, which is always contained in the hydraulic fluid circuit and the disadvantages of which are not eliminated by the arrangement of the sealed air cushion.
  • This proportion of air in the hydraulic fluid can be disadvantageously particularly high if, when filling the hydraulic lash adjuster, air is included outside the membrane in the storage space, which then necessarily foams up during operation of the compensating element and also enters the work space via the check valve.
  • Another game compensation element shows the US-A-2096257.
  • This is also an element in which the storage space is under atmospheric pressure, so that the desired effect of existing air as an air cushion or pressure accumulator does not occur.
  • the storage space is deliberately partially filled with hydraulic fluid and partially with air, the hydraulic fluid being in direct, unimpeded communication with the air, so that the foaming process is in no way hindered.
  • a filter is arranged, which has the task of separating the air foamed in the hydraulic fluid and preventing it from entering the work space.
  • the filter has only a limited effectiveness with regard to its separation effect.
  • the problem in the air dissolved in the hydraulic fluid is addressed in DE-A-2517370.
  • the hydraulic fluid should flow completely into the work area and the storage room can be filled in freely.
  • the storage space is largely liquid-tight on the outside, ie sealed by a hose section made of rubber-like material against the escape of liquid.
  • the atmosphere or the oil pressure of the lubrication circuit acts on the outside of the hose section.
  • there is no possibility of briefly absorbing and releasing pressure peaks in an air cushion but on the other hand the foaming of air within the storage space is effectively avoided.
  • filling the compensating element with air-free hydraulic fluid requires certain precautions and great care.
  • the invention has for its object to provide a self-sufficient lash adjuster, which is therefore independent of the foaming of the engine oil, so that neither an inflation nor an empty pumping of the working space occurs under operating conditions, in particular at high speeds.
  • the known effect of an air cushion is to be used in an advantageous manner to absorb pressure peaks and to supplement the amount of leakage between the working space and the storage space with sufficient pressure drop during the short time available.
  • the penetration of the hydraulic fluid mixed with air into the work area must be prevented, i.e. the liquid entering the work area must be largely free of air, i.e. may only contain air up to a certain limit.
  • the element preventing the foaming is a filling made of packing elements which receive the air cushion finely distributed between them.
  • This makes it possible to easily fill the lash adjuster with hydraulic fluid that contains a certain amount of air. A separate introduction of air is avoided.
  • the arrangement of the filling made of packing elements at least some of the air is finely distributed and acts as an air cushion, between or in the filling elements, where it is largely removed in a fixed position.
  • this air cushion is effectively prevented from foaming, since it is prevented by forces within the filling material from loosening and foaming in the hydraulic fluid.
  • filling of fillers can fill the entire storage space. In general, however, it is already sufficient if part of the storage space is filled with a packing.
  • the fillers can have an airtight and liquid-tight surface, that is to say, for example, consist of glass balls, plastic beads or the like.
  • the size of the packing has a major influence on the retention of the finely divided air.
  • the fillers can also be filled very easily into the otherwise pressure-tight storage space through the channel that connects the storage space with the work space.
  • the fillers may consist of a sponge-like material which is impregnated with hydraulic fluid which forms the air cushion with its predetermined proportion of air.
  • the 'shown in FIG. 1 hydraulic clearance compensation element consists essentially of two mutually displaceable parts, namely a piston 1 and an associated cylinder 2.
  • the cylinder 2' itself is again slidably mounted to a respective housing part, which is not shown here.
  • a reservoir 3 is provided in the cylinder 2 and is filled with hydraulic fluid.
  • the storage space 3 is designed to be pressure-tight with respect to the atmosphere.
  • a working space 5 is also provided, which is also filled with hydraulic fluid.
  • a check valve 7 is switched on in the channel 6 between the storage space 3 and the working space 5.
  • the piston 1 is supported relative to the cylinder 2 by a spring 8, which can also be provided elsewhere, but with the same effect.
  • the connection from the working space 5 to the storage space 3 is established via a throttling gap 9 formed as an annular gap between the cylinder 2 and the piston 1.
  • the circuit of the hydraulic fluid is therefore clear and with the help of the check valve 7 certainly.
  • Hydraulic fluid 14 can only reach the working space 5 from the storage space 3 via the channel 6.
  • hydraulic fluid 14 displaced from the working space 5 can only reach the storage space 3 via the throttle gap 9.
  • the throttle gap 9 ends at an annular groove 10 with a bore 11 which connects to the storage space 3.
  • an indented annular plate 21 is provided, both of which ensure that the storage space 3 is pressure-tight against the atmosphere.
  • packing elements are provided either continuously or as a loose bed, which take up finely divided air in the form of an air cushion 13 between them, so that this air cannot separate from the packing elements 22 even at high acceleration forces and therefore does not foam.
  • the air cushion 13 is sufficient to absorb and release pressure peaks and thus to act as described.
  • FIG. 2 shows a hydraulic tappet, the storage space 3 of which is formed in the piston 1 and is provided with a filling of fillers 22 that completely occupies it, as has already been explained with reference to the tappet according to FIG. 1.
  • the fillers 22 can be designed with a dense surface, i.e. represent airtight bodies, for example glass spheres, plastic beads or the like.

Abstract

1. Hydraulic play-compensating element with a piston displaceably guided in a cylinder and a working chamber formed between piston and cylinder and a reservoir chamber which is arranged in the piston and/or cylinder, is closed off outwardly to the pressure-tight, is partially filled by an air cushion and partly by hydraulic fluid and in which an element hindering the foaming of air in hydraulic fluid is provided wherein the reservoir chamber stands in communication with the working chamber through a channel displaying a non-return valve and the working chamber is connected through a throttle gap, characterised thereby, that the element hindering the foaming is a filling of filler bodies (22; 23), which receive the air cushion (13) finely distributed between them.

Description

Die Erfindung bezieht sich auf ein hydraulisches Spielausgleichselement mit einem in einem Zylinder verschiebbar geführten Kolben und einem zwischen Kolben und Zylinder gebildeten Arbeitsraum und einem im Kolben und/ oder im Zylinder angeordneten nach aussen druckdicht abgeschlossenen Vorratsraum, der teilweise mit einem Luftpolster und teilweise mit Hydraulikflüssigkeit gefüllt ist und in dem ein die Verschäumung von Luft in Hydraulikflüssigkeit behinderndes Element vorgesehen ist, wobei der Vorratsraum mit dem Arbeitsraum über einen ein Rückschlagventil aufweisenden Kanal in Verbindung steht und der Arbeitsraum mit dem Vorratsraum über einen Drosselspalt verbunden ist. Derartige hydraulische Spielausgleichselemente werden insbesondere für die Steuerung der Ventile von Brennkraftmaschinen eingesetzt.The invention relates to a hydraulic lash adjuster with a piston displaceably guided in a cylinder and a working space formed between the piston and the cylinder and a storage space arranged in the piston and / or in the cylinder and sealed to the outside in a pressure-tight manner, which is partly filled with an air cushion and partly with hydraulic fluid and in which an element preventing the foaming of air in hydraulic fluid is provided, the storage space being connected to the working space via a channel having a check valve and the working space being connected to the storage space via a throttle gap. Such hydraulic lash adjusters are used in particular for the control of the valves of internal combustion engines.

Die US-A-2694388 und die DE-A-2911550 zeigen ein derartiges hydraulisches Spielausgleichselement, bei welchem der Vorratsraum druckdicht gegenüber der Atmosphäre abgeschlossen ist. Im Vorratsraum ist ein Luftpolster angeordnet und vorgesehen, welches von der Hydraulikflüssigkeit im Vorratsraum durch eine Membran, einen eine Kammer für das Luftpolster bildenden Ballonkörper od. dgl. getrennt ist. Die Membran ist dabei flüssigkeits- und luftdicht ausgebildet, so dass das Luftpolster jederzeit wirksam getrennt von der Hydraulikflüssigkeit im Vorratsraum gehalten wird. Das eingeschlossene Luftpolster ist geeignet, auftretende Druckspitzen kurzzeitig aufzunehmen und an die Hydraulikflüssigkeit im Vorratsraum wieder abzugeben, wenn bei geöffnetem Rückschlagventil ein Nachfüllen des Arbeitsraumes aus dem Vorratsraum heraus erforderlich ist. Während das von der Membran eingeschlossene Luftpolster keine Möglichkeit hat, mit der Hydraulikflüssigkeit aufzuschäumen, enthält die Hydraulikflüssigkeit selbst noch einen gewissen Luftanteil, der immer im Kreislauf der Hydraulikflüssigkeit beinhaltet bleibt und dessen Nachteile durch die Anordnung des abgeschlossenen Luftpolsters auch nicht beseitigt werden. Dieser Luftanteil in der Hydraulikflüssigkeit kann dadurch in nachteiliger Weise besonders hoch werden, wenn beim Füllen des hydraulischen Spielausgleichselementes Luft ausserhalb der Membran im Vorratsraum mit eingeschlossen wird, die dann im Betrieb des Ausgleichselementes notwendigerweise aufschäumt und auch über das Rückschlagventil in den Arbeitsraum gelangt.US-A-2694388 and DE-A-2911550 show such a hydraulic lash adjuster, in which the storage space is sealed pressure-tight from the atmosphere. An air cushion is arranged and provided in the storage space, which is separated from the hydraulic fluid in the storage space by a membrane, a balloon body or the like forming a chamber for the air cushion. The membrane is designed to be liquid and airtight, so that the air cushion is kept effectively separate from the hydraulic fluid in the storage space at all times. The enclosed air cushion is suitable for briefly absorbing pressure peaks that occur and releasing them back to the hydraulic fluid in the reservoir if the work space needs to be refilled from the reservoir with the check valve open. While the air cushion enclosed by the membrane has no possibility of foaming with the hydraulic fluid, the hydraulic fluid itself still contains a certain amount of air, which is always contained in the hydraulic fluid circuit and the disadvantages of which are not eliminated by the arrangement of the sealed air cushion. This proportion of air in the hydraulic fluid can be disadvantageously particularly high if, when filling the hydraulic lash adjuster, air is included outside the membrane in the storage space, which then necessarily foams up during operation of the compensating element and also enters the work space via the check valve.

Aus der US-A-3 025 842 oder auch der US-A-2 246 330 sind Spielausgleichselemente bekannt, deren Vorratsraum jedoch nicht druckdicht gegenüber der Atmosphäre abgeschlossen ist, sondern mit dem ölkreislauf der'Brennkraftmaschine in Verbindung steht. Auch das Öl des Ölkreislaufes neigt innerhalb desselben zum Aufschäumen, so dass beim Nachfüllen des Vorratsraumes auch Luft mit eingebracht wird. Um diesem Einschleppen von Luft entgegenzuwirken, sind am Übergang zwischen dem ölkreislauf und dem Vorratsraum ein oder mehrere filterartig wirkende Elemente, die insbesondere aus faserigem Material bestehen, angeordnet. Diese Filterelemente sollen eine Abscheidung der neu mit eingeschleppten Luft bewirken, so dass eine Luftanreicherung innerhalb des Vorratsraumes vermieden wird. Auch mit dieser Konstruktion wird auf die Luft, die innerhalb der Hydraulikflüssigkeit im Arbeitsraum und im Vorratsraum enthalten ist, kein ausreichender Einfluss genommen. Ganz abgesehen davon kann die in diesem Kreislauf enthaltene Luft ungehindert immer wieder aufschäumen und auf diese Art und Weise auch in den Arbeitsraum gelangen. Darüber hinaus besitzen derartige Ausgleichselemente aber auch den Nachteil, dass infolge des Anschlusses des Vorratsraumes an den Motorölkreislauf die Luft auch wieder entweichen kann und sodann die Möglichkeit fehlt, dass die Luft als Luftpolster wirkend Druckspitzen kurzzeitig speichern kann.From US-A-3 025 842 or also US-A-2 246 330 lash adjuster elements are known, the storage space of which, however, is not sealed off from the atmosphere in a pressure-tight manner, but is connected to the oil circuit of the internal combustion engine. The oil in the oil circuit also tends to foam within it, so that air is also introduced when the storage space is refilled. In order to counteract this entrainment of air, one or more filter-like elements, which consist in particular of fibrous material, are arranged at the transition between the oil circuit and the storage space. These filter elements are intended to separate the newly introduced air so that air accumulation within the storage space is avoided. With this construction, too, the air contained in the hydraulic fluid in the work space and in the storage space is not sufficiently influenced. Quite apart from this, the air contained in this circuit can foam up again and again and thus get into the work area. In addition, such compensating elements also have the disadvantage that the air can escape again as a result of connecting the storage space to the engine oil circuit and then there is no possibility that the air, acting as an air cushion, can briefly store pressure peaks.

Ein weiteres Spielausgleichselement zeigt die US-A-2096257. Dabei handelt es sich ebenfalls um ein Element, bei dem der Vorratsraum unter Atmosphärendruck steht, so dass die erwünschte Wirkung vorhandener Luft als Luftpolster bzw. Druckspeicher nicht eintritt. Bei diesem bekannten Spielausgleichselement ist der Vorratsraum ganz bewusst teilweise mit Hydraulikflüssigkeit und teilweise mit Luft gefüllt, wobei die Hydraulikflüssigkeit in direkter ungehinderter Verbindung zu der Luft steht, so dass der Aufschäumvorgang in keiner Weise behindert wird. Am Übergang von dem Vorratsraum in den das Rückschlagventil tragenden Kanal, der zum Arbeitsraum führt, ist ein Filter angeordnet, welches die Aufgabe hat, die in der Hydraulikflüssigkeit aufgeschäumte Luft abzuscheiden und an einem Durchtritt in den Arbeitsraum zu hindern. Das Filter besitzt jedoch hinsichtlich seiner Abscheidewirkung nur eine begrenzte Wirksamkeit. Infolge der fortlaufenden ungehinderten Verschäumung im Vorratsraum wird sich ein erhöhter Luftanteil im Arbeitsraum einstellen, der die lmkompressibilität beeinträchtigt. Ausserdem behindert das Filter am Eingang des Kanals zwischen Vorratsraum und Arbeitsraum den ungehinderten schnellen Durchtritt von Hydraulikflüssigkeit in den Arbeitsraum in nachteiliger Weise. Bei hohen Drehzahlen reicht deshalb diese Behinderung schon aus, um den Nachfüllvorgang nur begrenzt ablaufen zu lassen, so dass letztlich ein Leerpumpen des Arbeitsraumes bei bestimmten Betriebsbedingungen eintritt.Another game compensation element shows the US-A-2096257. This is also an element in which the storage space is under atmospheric pressure, so that the desired effect of existing air as an air cushion or pressure accumulator does not occur. In this known lash adjuster, the storage space is deliberately partially filled with hydraulic fluid and partially with air, the hydraulic fluid being in direct, unimpeded communication with the air, so that the foaming process is in no way hindered. At the transition from the storage space into the channel carrying the check valve, which leads to the work space, a filter is arranged, which has the task of separating the air foamed in the hydraulic fluid and preventing it from entering the work space. However, the filter has only a limited effectiveness with regard to its separation effect. As a result of the continuous, unimpeded foaming in the storage room, an increased proportion of air will set in the work area, which impairs the compressibility. In addition, the filter at the entrance of the channel between the storage space and the work space disadvantageously prevents the unimpeded rapid passage of hydraulic fluid into the work space. At high speeds, this hindrance is sufficient to allow the refilling process to take place only to a limited extent, so that ultimately the working area is emptied under certain operating conditions.

Das Problem in der der Hydraulikflüssigkeit gelösten Luft wird in der DE-A-2517370 angesprochen. Die Hydraulikflüssigkeit soll in den Arbeitsraum und in den Vorratsraum völlig luftfrei eingefüllt werden. Die Vorratsraum ist nach aussen weitgehend flüssigkeitsdicht gestaltet, d.h. von einem Schlauchabschnitt aus gummiartigem Material gegen den Austritt von Flüssigkeit gedichtet. Auf die Aussenseite des Schlauchabschnittes wirkt die Atmosphäre bzw. der Öldruck des Schmieröikreisiaufes ein. Hier fehlt die Möglichkeit, in einem Luftpolster Druckspitzen kurzzeitig aufzunehmen und wieder abzugeben, andererseits wird aber das Aufschäumen von Luft innerhalb des Vorratsraumes wirksam vermieden. Das Füllen des Ausgleichselementes mit luftfreier Hydraulikflüssigkeit erfordert aber bestimmte Vorkehrungen und eine hohe Sorgfalt. Da keinerlei Luft innerhalb der Hydraulikflüssigkeit vorhanden sein soll, ist es erforderlich, die Leckmenge im 'Drosseispait sehr genau festzulegen, damit dieses Element in einem Drehzahlbereich zufriedenstellend arbeiten kann. Wird das Element auf niedrige Drehzahlen ausgerichtet, dann versagt es bei hohen Drehzahlen und umkehrt. Es kann sowohl ein Aufpumpen als auch ein Leerpumpen eintreten, was beides schädlich ist. Ein Aufpumpen kann zur gewaltsamen Zerstörung des Ventiltriebes führen. Beim Leerpumpen wird das erforderliche Ventilspiel überhaupt nicht mehr eingehalten.The problem in the air dissolved in the hydraulic fluid is addressed in DE-A-2517370. The hydraulic fluid should flow completely into the work area and the storage room can be filled in freely. The storage space is largely liquid-tight on the outside, ie sealed by a hose section made of rubber-like material against the escape of liquid. The atmosphere or the oil pressure of the lubrication circuit acts on the outside of the hose section. Here there is no possibility of briefly absorbing and releasing pressure peaks in an air cushion, but on the other hand the foaming of air within the storage space is effectively avoided. However, filling the compensating element with air-free hydraulic fluid requires certain precautions and great care. Since no air should be present in the hydraulic fluid, it is necessary to determine the leakage quantity in the 'Drossseispait very precisely so that this element can work satisfactorily in a speed range. If the element is aligned at low speeds, it will fail at high speeds and vice versa. Both inflation and deflation can occur, both of which are harmful. Inflation can lead to the violent destruction of the valve train. When pumping empty, the required valve clearance is no longer maintained.

Der Erfindung liegt die Aufgabe zugrunde, ein autarkes Spielausgleichselement, welches also von der Aufschäumung des Motoröls unabhängig ist, so auszubilden, dass weder ein Aufpumpen noch ein Leerpumpen des Arbeitsraumes unter Betriebsbedingungen, insbesondere bei hohen Drehzahlen, auftritt. Dabei soll einerseits in vorteilhafter Weise die bekannte Wirkung eines Luftspolsters genutzt werden, um Druckspitzen aufzunehmen und mit ausreichendem Druckgefälle während der kurzen zur Verfügung stehenden Zeit jeweils die Leckmenge zwischen Arbeitsraum und Vorratsraum zu ergänzen. Dabei muss jedoch das Eindringen der mit Luft vermischten Hydraulikflüssigkeit in den Arbeitsraum verhindert werden, d.h. die in den Arbeitsraum gelangende Flüssigkeit muss weitgehend luftfrei sein, d.h. darf Luft nur bis zu einem gewissen Grenzwert enthalten.The invention has for its object to provide a self-sufficient lash adjuster, which is therefore independent of the foaming of the engine oil, so that neither an inflation nor an empty pumping of the working space occurs under operating conditions, in particular at high speeds. On the one hand, the known effect of an air cushion is to be used in an advantageous manner to absorb pressure peaks and to supplement the amount of leakage between the working space and the storage space with sufficient pressure drop during the short time available. However, the penetration of the hydraulic fluid mixed with air into the work area must be prevented, i.e. the liquid entering the work area must be largely free of air, i.e. may only contain air up to a certain limit.

Erfindungsgemäss wird dies dadurch erreicht, dass das die Verschäumung behindernde Element eine Füllung aus Füllkörpern ist, die zwischen sich feinverteilt das Luftpolster aufnehmen. Damit ist es möglich, in einfacher Weise das Spielausgleichselement mit Hydraulikflüssigkeit, die einen bestimmten Luftanteil enthält, zu füllen. Ein gesondertes Einführen von Luft wird vermieden. Durch die Anordnung der Füllung aus Füllkörpern lagert sich zumindest ein Teil der Luft feinverteilt und als Luftpolster wirkend an, zwischen bzw. in den Füllkörpern ab, wo es weitgehend ortsfest aufgehoben ist. Dieses Luftpolster ist einerseits wirksam an einem Aufschäumen gehindert, da es durch Kräfte innerhalb der Füllkörperfüllung gehindert ist, sich zu lösen und in der Hydraulikflüssigkeit aufzuschäumen. Andererseits ist es möglich, damit den Luftanteil der Hydraulikflüssigkeit im Arbeitsraum festzulegen und zu begrenzen, so dass die Inkompressibiiität der Hydraulikflüssigkeit nur in dem für das ordnungsgemässe Arbeiten des Spielausgleichselementes erforderlichen Masse beeinträchtigt wird. Wesentlich ist also dabei, durch die Füllkörper die Luft feinverteilt in den Zwischenräumen oder im Innern der Füllkörper festzuhalten, wo sie insgesamt ein Luftpolster bildet, aber andererseits keine Möglichkeit besteht, zu einem nennenswerten Teil innerhalb der Hydraulikflüssigkeit aufzuschäumen.According to the invention, this is achieved in that the element preventing the foaming is a filling made of packing elements which receive the air cushion finely distributed between them. This makes it possible to easily fill the lash adjuster with hydraulic fluid that contains a certain amount of air. A separate introduction of air is avoided. As a result of the arrangement of the filling made of packing elements, at least some of the air is finely distributed and acts as an air cushion, between or in the filling elements, where it is largely removed in a fixed position. On the one hand, this air cushion is effectively prevented from foaming, since it is prevented by forces within the filling material from loosening and foaming in the hydraulic fluid. On the other hand, it is possible to determine and limit the proportion of air in the hydraulic fluid in the work area, so that the incompressibility of the hydraulic fluid is only impaired to the extent necessary for the correct functioning of the play compensation element. It is therefore essential here to hold the air finely distributed in the interstices or in the interior of the packing, where it forms an air cushion overall, but on the other hand there is no possibility of foaming to any appreciable extent within the hydraulic fluid.

Die Füllung aus Füllkörpern kann den gesamten Vorratsraum ausfüllen. Im allgemeinen genügt es jedoch bereits, wenn ein Teil des Vorratsraumes mit einer Füllkörperfüllung versehen ist.The filling of fillers can fill the entire storage space. In general, however, it is already sufficient if part of the storage space is filled with a packing.

Die Füllkörper können eine luft- und flüssigkeitsdichte Oberfläche aufweisen, also beispielsweise aus Glaskugeln, Kunststoffperlen od. dgl. bestehen. Die Grösse der Füllkörper ist von wesentlichem Einfluss auf das Festhaltevermögen der feinverteilten Luft. Die Füllkörper lassen sich in den ansonsten druckdicht abgeschlossenen Vorratsraum auch sehr einfach durch den Kanal einfüllen, der den Vorratsraum mit dem Arbeitsraum verbindet.The fillers can have an airtight and liquid-tight surface, that is to say, for example, consist of glass balls, plastic beads or the like. The size of the packing has a major influence on the retention of the finely divided air. The fillers can also be filled very easily into the otherwise pressure-tight storage space through the channel that connects the storage space with the work space.

Es ist aber auch möglich, dass die Füllkörper aus einem schwammartigen Material bestehen, welches mit Hydraulikflüssigkeit getränkt ist, die mit ihrem vorgegebenen Luftanteil das Luftpolster bildet.However, it is also possible for the fillers to consist of a sponge-like material which is impregnated with hydraulic fluid which forms the air cushion with its predetermined proportion of air.

Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und werden im folgenden näher beschrieben. Es zeigen:

  • Fig. 1 einen Querschnitt durch das Spielausgleichselement als hydraulischer Tassenstösse'l,
  • Fig. 2 einen Querschnitt durch das Spielausgleichselement als hydraulischer Stössel und
  • Fig. 3 einen Querschnitt durch das Spielausgleichselement als hydraulischer Stössel in einer weiteren Ausführungsform.
Embodiments of the invention are shown in the drawing and are described in more detail below. Show it:
  • 1 shows a cross section through the play compensation element as a hydraulic cup push ' 1,
  • Fig. 2 shows a cross section through the play compensation element as a hydraulic ram and
  • Fig. 3 shows a cross section through the play compensation element as a hydraulic tappet in a further embodiment.

Das 'in Fig. 1 dargestellte hydraulische Spielausgleichselement besteht im wesentlichen aus zwei gegeneinander verschiebbaren Teilen, nämlich einem Kolben 1 und einem zugehörigen Zylinder 2. Der Zylinder '2 selbst ist auch wieder gleitend mit einem entsprechenden Gehäuseteil, welches hier nicht dargestellt ist, gelagert. Im Zylinder 2 ist ein Vorratsraum 3 vorgesehen, der mit Hydraulikflüssigkeit gefüllt ist. Der Vorratsraum 3 ist druckdicht gegenüber der Atmosphäre ausgebildet. Zwischen Kolben 1 und Zylinder 2 ist weiterhin ein Arbeitsraum 5 vorgesehen, der ebenfalls mit Hydraulikflüssigkeit gefüllt ist. In den Kanal 6 zwischen Vorratsraum 3 und Arbeitsraum 5 ist ein Rückschlagventil 7 eingeschaltet. Der Kolben 1 ist gegenüber dem Zylinder 2 über eine Feder 8 abgestützt, die auch an anderer Stelle, jedoch gleichwirkend, vorgesehen sein kann. Die Verbindung von dem Arbeitsraum 5 zu dem Vorratsraum 3 ergibt sich über einen als Ringspalt ausgebildeten Drosselspalt 9 zwischen Zylinder 2 und Kolben 1. Der Kreislauf der Hydraulikflüssigkeit ist also damit und mit Hilfe des Rückschlagventils 7 eindeutig bestimmt. Hydraulikflüssigkeit 14 kann vom Vorratsraum 3 nur über den Kanal 6 in den Arbeitsraum 5 gelangen. Andererseits kann aus dem Arbeitsraum 5 verdrängte Hydraulikflüssigkeit 14 nur über den Drosselspalt 9 in den Vorratsraum 3 gelangen. Zu diesem Zweck endet der Drosselspalt 9 an einer Ringnut 10 mit Bohrung 11, die an den Vorratsraum 3 anschliesst. Neben einer Dichtung 4 zwischen Zylinder und Kolben ist eine eingedrückte Kreisringplatte 21 vorgesehen, die beide für eine druckdichte Ausbildung des Vorratsraumes 3 gegenüber der Atmosphäre sorgen. Im Vorratsraum 3 sind Füllkörper entweder zusammenhängend oder als lose Schüttung vorgesehen, die zwischen sich feinverteilt Luft in Form eines Luftpolsters 13 aufnehmen, so dass diese Luft sich von den Füllkörpern 22 auch bei hohen Beschleunigungskräften nicht lösen kann und daher auch nicht aufschäumt. Andererseits aber ist das Luftpolster 13 ausreichend, um Druckspitzen aufzunehmen und wieder abzugeben und damit so zu wirken, wie dies beschrieben wurde.The 'shown in FIG. 1 hydraulic clearance compensation element consists essentially of two mutually displaceable parts, namely a piston 1 and an associated cylinder 2. The cylinder 2' itself is again slidably mounted to a respective housing part, which is not shown here. A reservoir 3 is provided in the cylinder 2 and is filled with hydraulic fluid. The storage space 3 is designed to be pressure-tight with respect to the atmosphere. Between the piston 1 and cylinder 2, a working space 5 is also provided, which is also filled with hydraulic fluid. A check valve 7 is switched on in the channel 6 between the storage space 3 and the working space 5. The piston 1 is supported relative to the cylinder 2 by a spring 8, which can also be provided elsewhere, but with the same effect. The connection from the working space 5 to the storage space 3 is established via a throttling gap 9 formed as an annular gap between the cylinder 2 and the piston 1. The circuit of the hydraulic fluid is therefore clear and with the help of the check valve 7 certainly. Hydraulic fluid 14 can only reach the working space 5 from the storage space 3 via the channel 6. On the other hand, hydraulic fluid 14 displaced from the working space 5 can only reach the storage space 3 via the throttle gap 9. For this purpose, the throttle gap 9 ends at an annular groove 10 with a bore 11 which connects to the storage space 3. In addition to a seal 4 between the cylinder and piston, an indented annular plate 21 is provided, both of which ensure that the storage space 3 is pressure-tight against the atmosphere. In the storage space 3, packing elements are provided either continuously or as a loose bed, which take up finely divided air in the form of an air cushion 13 between them, so that this air cannot separate from the packing elements 22 even at high acceleration forces and therefore does not foam. On the other hand, however, the air cushion 13 is sufficient to absorb and release pressure peaks and thus to act as described.

Fig. 2 zeigt einen hydraulischen Stössel, dessen im Kolben 1 ausgebildeter Vorratsraum 3 mit einer diesen ganz einnehmenden Füllung aus Füllkörpern 22 versehen ist, wie sie anhand des Tassenstössels gemäss Fig. 1 bereits erläutert wurden. Die Füllkörper 22 können mit dichter Oberfläche ausgebildet sein, also luftdichte Körper darstellen, beispielsweise Glaskugeln, Kunststoffperlen od. dgl. Es ist aber auch möglich, gemäss Fig. 3 als Schwellkörper ausgebildete Füllkörper 23 aus schwammartigem Material einzubringen, die zumindest teilweise in ihrem Innern die Luft bzw. insgesamt das Luftpolster 13 aufnehmen und binden.FIG. 2 shows a hydraulic tappet, the storage space 3 of which is formed in the piston 1 and is provided with a filling of fillers 22 that completely occupies it, as has already been explained with reference to the tappet according to FIG. 1. The fillers 22 can be designed with a dense surface, i.e. represent airtight bodies, for example glass spheres, plastic beads or the like. However, it is also possible, according to FIG. 3, to introduce fillers 23 made of sponge-like material, which at least partially inside the Air and collect the air cushion 13 and bind.

Claims (4)

1. Hydraulic play-compensating element with a piston displaceably guided in a cylinder and a working chamber formed between piston and cylinder and a reservoir chamber which is arranged in the piston and/or cylinder, is closed off outwardly to the pressure-tight, is partially filled by an air cushion and partly by hydraulic fluid and in which an element hindering the foaming of air in hydraulic fluid is provided, wherein the reservoir chamber stands in communication with the working chamber through a channel displaying a non-return valve and the working chamber is connected through a throttle gap, characterised thereby, that the element hindering the foaming is a filling of filler bodies (22; 23), which receive the air cushion (13) finely distributed between them.
2. Hydraulic play-compensating element according to claim 1, characterised thereby, that the filling of filler bodies (22, 23) fills out the entire reservoir chamber (3).
3. Hydraulic play-compensating element according to claim 1 or 2, characterised thereby, that the filler bodies (22) display a surface tight to air and fluid.
4. Hydraulic play-compensating element according to claim 1 or 2, characterised thereby, that the filler bodies (23) consist of a sponge- like material which is impregnated with hydraulic fluid (14), which by its predetermined air component forms the air cushion (13).
EP79104279A 1978-11-03 1979-11-02 Hydraulic backlash adjuster Expired EP0010768B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT79104279T ATE980T1 (en) 1978-11-03 1979-11-02 HYDRAULIC PLAY COMPENSATION.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2847699A DE2847699C3 (en) 1978-11-03 1978-11-03 Hydraulic lash adjuster
DE2847699 1978-11-03

Publications (2)

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EP0010768A1 EP0010768A1 (en) 1980-05-14
EP0010768B1 true EP0010768B1 (en) 1982-05-05

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EP79104279A Expired EP0010768B1 (en) 1978-11-03 1979-11-02 Hydraulic backlash adjuster

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EP (1) EP0010768B1 (en)
AT (1) ATE980T1 (en)
DE (1) DE2847699C3 (en)

Cited By (1)

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US20100282194A1 (en) * 2008-08-28 2010-11-11 Toyota Jidosha Kabushiki Kaisha Sealed-type lash adjuster

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DE3072169D1 (en) * 1979-12-05 1990-01-18 Eaton Corp HYDRAULIC VALVE TUNEL FOR A DIRECTLY DRIVED VALVE CONTROL.
IT1129888B (en) * 1980-11-21 1986-06-11 Riv Officine Di Villar Perosa HYDRAULIC TAPPETS WITH AUTOMATIC RESUME OF GAME FOR ENDOTHERMAL ENGINES
AU8851382A (en) * 1981-12-28 1983-07-07 Stanadyne Inc. Hydraulic valve lifters
GB2185549B (en) * 1985-10-15 1990-01-24 Honda Motor Co Ltd Hydraulic lash adjuster for use in a valve operating mechanism
US4917059A (en) * 1988-03-31 1990-04-17 Nippon Seiko Kabushiki Kaisha Valve lash adjuster
DE4026793A1 (en) * 1990-08-24 1992-03-05 Freudenberg Carl Fa HYDRAULIC VALVE COMPENSATION COMPENSATION ELEMENT FOR INTERNAL COMBUSTION ENGINES
FR2677704B1 (en) * 1991-06-14 1995-02-17 Renault HYDRAULIC GAME RETRIEVAL DEVICE FOR DISTRIBUTION OF INTERNAL COMBUSTION ENGINE.
DE4203897C2 (en) * 1992-02-11 1994-01-27 Freudenberg Carl Fa Hydraulic valve lash adjuster
DE4442932A1 (en) * 1994-12-02 1996-06-05 Schaeffler Waelzlager Kg Hydraulic clearance compensation element for valve control of IC engine
DE10010597A1 (en) * 2000-03-03 2001-09-06 Mahle Ventiltrieb Gmbh Hydraulic tappet clearance compensation element esp. for gas exchange valve control in IC engines has volume-varying adjuster piston sealed via sliding seal ring
JP4680155B2 (en) 2005-11-08 2011-05-11 トヨタ自動車株式会社 Sealed lash adjuster and method for adjusting liquid filling amount of sealed lash adjuster

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DE1911550A1 (en) * 1969-03-07 1970-09-24 Hanning Elektro Werke Heating circulation pump
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US3025842A (en) * 1961-02-06 1962-03-20 Gen Motors Corp Self-contained hydraulic lash adjuster
DE2911550C2 (en) * 1978-03-23 1982-12-23 Aisin Seiki K.K., Kariya, Aichi Valve clearance compensation device

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US2096257A (en) * 1935-06-17 1937-10-19 Moorhouse Alfred Hydraulic valve tappet
US2246330A (en) * 1940-03-14 1941-06-17 Eaton Mfg Co Hydraulic tappet construction
DE1911550A1 (en) * 1969-03-07 1970-09-24 Hanning Elektro Werke Heating circulation pump
DE2517370A1 (en) * 1975-04-19 1976-10-28 Volkswagenwerk Ag Hydraulic clearance compensating device for IC engine valves - has hydraulic medium filled pre-chamber sealed with elastic membrane

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100282194A1 (en) * 2008-08-28 2010-11-11 Toyota Jidosha Kabushiki Kaisha Sealed-type lash adjuster

Also Published As

Publication number Publication date
EP0010768A1 (en) 1980-05-14
DE2847699C3 (en) 1982-03-04
DE2847699B2 (en) 1981-07-02
DE2847699A1 (en) 1980-05-14
ATE980T1 (en) 1982-05-15

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