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EP0525284B1 - Hydraulic valve lash adjuster for internal combustion engine - Google Patents

Hydraulic valve lash adjuster for internal combustion engine Download PDF

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Publication number
EP0525284B1
EP0525284B1 EP92103236A EP92103236A EP0525284B1 EP 0525284 B1 EP0525284 B1 EP 0525284B1 EP 92103236 A EP92103236 A EP 92103236A EP 92103236 A EP92103236 A EP 92103236A EP 0525284 B1 EP0525284 B1 EP 0525284B1
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EP
European Patent Office
Prior art keywords
housing
hollow cylinder
compensating device
clearance compensating
valve clearance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP92103236A
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German (de)
French (fr)
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EP0525284A1 (en
Inventor
Volker Budde
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Carl Freudenberg KG
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Carl Freudenberg KG
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Publication of EP0525284A1 publication Critical patent/EP0525284A1/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
    • F01L1/25—Hydraulic tappets between cam and valve stem

Definitions

  • the invention relates to a hydraulic valve lash adjuster for an internal combustion engine, in which a lash adjuster in a cylindrical guide can be moved up and down in the axial direction, comprising a first and a second hollow cylinder, which are sealed against one another and axially elastically supported on one another by a compression spring and by one essentially cup-shaped housing with a flat bottom and with at least one circumferentially arranged lubricant passage opening are concentrically enclosed, the first hollow cylinder and the lubricant passage opening being connected in a liquid-conducting manner, and wherein the lubricant passage opening on the side facing the hollow cylinders is assigned a first check valve that the lubricant passage through the opening releases in the direction of the first hollow cylinder and blocks the backflow from the first hollow cylinder through the opening.
  • valve lash adjuster is known from DE-OS 31 50 083.
  • a flexible rubber seal then forms a first check valve for sealing the reservoir for a hydraulic pressure medium.
  • the valve tappet contains the amount of pressure medium required for correct operation because the return flow of the pressure medium from the tank is blocked by the flexible rubber check valve. It should be noted, however, that the valve tappet is supplied with a lubricant from the lubricant circuit through a feed hole Internal combustion engine is filled. Such a configuration requires a high production outlay due to the bores arranged in the cylinder head and is therefore unsatisfactory in economic terms.
  • the invention has for its object to further develop a device of the type mentioned in such a way that the first hollow cylinder is always filled with pressure medium, even if the valves are kept in the open position when the internal combustion engine is at a long standstill, and that no oil supply holes specially provided for this purpose are used to fill the play compensation element is provided in the cylinder head.
  • the housing has an outer diameter in at least one partial area, which is reduced in size from the opening area to the bottom, the partial area of the housing and the guide delimiting a wedge-shaped gap in the axial direction, which in the Level of the floor is open.
  • the oil used for filling is spray oil that is present in the cylinder head for the lubrication of the camshaft, cam and tappet anyway.
  • the valve When the upward stroke has ended, the valve is in the closed position and the two hollow cylinders have the greatest possible distance from one another in the axial direction, due to the compression spring.
  • the lash adjuster To open the valve, the lash adjuster is moved downwards by a cam. Both the second check valve, which separates the second hollow cylinder from the first hollow cylinder, and the first check valve, which blocks the backflow from the first hollow cylinder through the opening in the direction of the cylinder head, are closed.
  • an almost rigid connection between the camshaft and valve is established in the axial direction, and on the other hand, causes at least the first hollow cylinder to be completely filled with oil in every operating state of the engine, even after a long standstill.
  • the main advantage is the fact that the difficult to manufacture feed holes in the cylinder head, which were previously required to supply the lash adjuster with lubricant, are avoided.
  • the configuration according to the invention is particularly advantageous in economic terms.
  • the housing can have a uniformly reduced outer diameter along a circumferential line in all partial areas.
  • This form of housing can be produced in a particularly simple manner, which gives advantages in terms of economy.
  • the housing has at least one segment-like wedge-shaped section on the circumference, the boundaries of which have the same outer diameter as the housing in the region of the cylindrical guide.
  • the advantage here is that the guide surface of the housing can be supported on a cylinder head over its entire axial extent in a guide bush. The Wear of the guide surface of the housing, caused by the tilting moments when the housing is moved in the axial direction, is thereby reduced comparatively.
  • four segment-like wedge-shaped sections are arranged along the circumference at right angles to one another.
  • the outer diameter can be continuously merging or reduced in steps.
  • the shape of the housing in this area can be particularly well adapted to the particular circumstances of the application. Some of the relevant parameters, on which the gap size between the housing and the guide depends, are formed by the first check valve, the size of the lubricant passage opening and the geometric dimensions of the hollow cylinder.
  • a partition is defined on the inside in the housing, which delimits an annular channel with the bottom, and that the channel is connected to the first hollow cylinder in a liquid-conducting manner.
  • the partition wall which fixes the first check valve, which consists for example of an elastically resilient material, in the radial direction in the region of the lubricant passage opening of the housing, ensures good performance characteristics with compact dimensions of the play compensation element.
  • the partition wall is touched on the side facing away from the bottom in the axial direction by the end face of the first hollow cylinder facing the channel and only by the second hollow cylinder with the greatest possible deflection.
  • the end face of the first hollow cylinder and / or the counter surface of the partition can be a pressure limitation in the first hollow cylinder Have a roughness depth of at least 1 ⁇ m. If a certain pressure in the first hollow cylinder is exceeded, the amount of liquid contained therein can escape in the form of a leak between the first hollow cylinder and the partition. Another leak that occurs during the intended use of the valve lash adjuster arises between the outer peripheral surface of the first hollow cylinder and the inner surface of the second hollow cylinder.
  • the second hollow cylinder can be captively, but axially displaceably arranged in the housing during use as intended.
  • the fastening element ensures simple assembly of the play compensation element in the valve train of an internal combustion engine.
  • the fastening element can, for example, be arranged in a groove along the inner circumferential surface of the housing and, in addition to the second hollow cylinder, can also fix the partition wall with the first check valve arranged therein in its radial direction.
  • this can be provided with recesses in the direction of the combustion chamber.
  • the partition and the fastening element can be formed in one piece and consist of polymeric material. This is advantageous both in terms of a further simplified assembly and in terms of the smallest possible mass of the play compensation element to be accelerated.
  • the fastening element can consist of a material with a particularly low coefficient of friction or can be provided with a surface coating which ensures low friction between the parts moving relative to one another.
  • a valve lash adjuster of the type according to the invention can be used in cylinder heads of internal combustion engines which do not have separate lines for filling the lash adjuster.
  • Fig. 1 two load conditions of the hydraulic valve lash adjuster are shown.
  • the second hollow cylinder 4 delimits the smallest volume of the high-pressure space and, with its end face open in the axial direction, lies against the partition 8.
  • the high-pressure space which is essentially delimited by the second hollow cylinder 4
  • the second hollow cylinder 4 bears in the axial direction with a projection on a stop surface of the fastening element 10.
  • the load state shown in the left part occurs, for example, when the lash adjuster 1 is arranged for a long time with the internal combustion engine switched off under axial load between a cam (not shown here) and an open valve.
  • a load state of the lash adjuster 1 is shown as it results during the operation of the internal combustion engine. Without external loads, i.e. at the top dead center of the game compensation element 1, the compression spring 5 moves the first 3 and second hollow cylinders 4 away from one another until the second hollow cylinder 4, which is relatively movable, comes to bear against the fastening element 10.
  • lubricant which is in the first hollow cylinder and in the channel 9 connected to it in a liquid-conducting manner can flow into the high-pressure chamber via the second check valve 13 and thus fill up with liquid volume displaced by leakage.
  • the play compensation element 1 is filled via a gap 12 which is formed by the housing 6 and the cylindrical guide 2. It is provided that the housing 6 has an outer diameter which is reduced in the area of the opening 6.2 starting in the direction of the bottom 6.1.
  • the function is as follows:
  • the starting point of the functional sequence is the position in which the valve of the internal combustion engine is fully open, ie the cam has brought the entire play compensation element 1 to its bottom dead center.
  • this oil is pressed into the wedge-shaped gap 12 and moved over the lubricant passage openings 6.2 past the first check valve 7 into the channel 9 and the first hollow cylinder 3.
  • the upward movement of the play compensation element 1 comes to a standstill at the top dead center. In this case, the valve of the internal combustion engine is closed.
  • the cam then moves the entire play compensation element 1 downward again to open the valve.
  • the first check valve 7 prevents the oil from flowing back out of the first hollow cylinder 3 and the channel 9 back through the lubricant passage opening 6.2 into the wedge-shaped gap 12.
  • the losses due to leakage in the high-pressure chamber are caused by a subsequent flow of the lubricant the first hollow cylinder 3 and the channel 9 equalized, so that a largely rigid connection between the cam and valve is formed.
  • the first check valve 7 prevents the first hollow cylinder 3 and the channel 9 from running empty with increasing time. This ensures that there is always sufficient oil in the channel 9 and in the first hollow cylinder 3 to supply the high-pressure space within the second hollow cylinder 4.
  • a hydraulic valve lash adjuster is shown, which is very similar to that in Fig. 1. It differs primarily in that the partition 8 and the fastening element 10 are formed in one piece and consist of polymeric material. The mode of operation is similar to that described above.
  • a valve lash adjuster is shown in perspective, in which the reduction of the outer diameter in the direction of the bottom 6.1 of the housing 6 is carried out only in segments.
  • the segment-like sections 12.1 have such an outer diameter in the area of their boundaries that there is a continuously constant outer diameter in the axial direction of the housing between the wedge-shaped sections 12.1.
  • the risk of tilting in a cylinder head (not shown here) during axial movement is significantly reduced by the comparatively large expansion of the housing 6 in the axial direction.
  • the main advantage of the invention can be seen in the oil supply, which takes place automatically during the upward movement of the play compensation element 1 by the pressure arising in the gap 12. This results in a significant simplification in the design and manufacture of the cylinder heads and cylinder blocks of the internal combustion engine.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Lubrication Of Internal Combustion Engines (AREA)
  • Check Valves (AREA)
  • Valve Device For Special Equipments (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Soil Working Implements (AREA)
  • Catching Or Destruction (AREA)
  • Mechanically-Actuated Valves (AREA)

Abstract

A hydraulic valve clearance compensator for an internal combustion engine. The compensator has a housing shaped essentially like an upside-down cup with a flat base. The housing slides up and down inside a central bore. The housing accommodates two concentric hollow cylinders sealed off from each other and separated by an axially resilient compression spring. In the wall of the housing there is at least one inlet that supplies lubricant to one cylinder. Between the inlet and the cylinders is a check valve that allows lubricant to flow through the inlet into the cylinder and prevents it from flowing out. At least the section of the housing between the inlet and the base is narrower than the rest of the housing.

Description

Die Erfindung betrifft eine hydraulische Ventilspielausgleichseinrichtung für eine Verbrennungskraftmaschine, bei der ein Spielausgleichselement in einer zylindrischen Führung in axialer Richtung auf und ab bewegbar ist, umfassend einen ersten und einen zweiten Hohlzylinder, die gegeneinander abgedichtet und durch eine Druckfeder axial elastisch aufeinander abgestützt sind und von einem im wesentlichen tassenförmigen Gehäuse mit ebenem Boden und mit zumindest einer umfangsseitig angeordneten Schmiermitteldurchtrittsöffnung konzentrisch umschlossen sind, wobei der erste Hohlzylinder und die Schmiermitteldurchtrittsöffnung flüssigkeitsleitend verbunden sind und wobei der Schmiermitteldurchtrittsöffnung auf der den Hohlzylindern zugewandten Seite ein erstes Rückschlagventil zugeordnet ist, das den Schmiermitteldurchtritt durch die Öffnung in Richtung des ersten Hohlzylinders frei gibt und den Rückfluß aus dem ersten Hohlzylinder durch die Öffnung sperrt.The invention relates to a hydraulic valve lash adjuster for an internal combustion engine, in which a lash adjuster in a cylindrical guide can be moved up and down in the axial direction, comprising a first and a second hollow cylinder, which are sealed against one another and axially elastically supported on one another by a compression spring and by one essentially cup-shaped housing with a flat bottom and with at least one circumferentially arranged lubricant passage opening are concentrically enclosed, the first hollow cylinder and the lubricant passage opening being connected in a liquid-conducting manner, and wherein the lubricant passage opening on the side facing the hollow cylinders is assigned a first check valve that the lubricant passage through the opening releases in the direction of the first hollow cylinder and blocks the backflow from the first hollow cylinder through the opening.

Eine solche Ventilspielausgleichseinrichtung ist aus der DE-OS 31 50 083 bekannt. Danach bildet eine flexible Gummidichtung ein erstes Rückschlagventil zur Abdichtung des Vorratsbehälters für ein hydraulisches Druckmittel. Selbst nach längerem Stillstand des Motors enthält der Ventilstößel die für den ordnungsgemäßen Betrieb notwendige Druckmittelmenge da der Rückfluß des Druckmittels aus dem Behälter durch das flexible Rückschlagventil aus Gummi gesperrt ist. Dabei ist allerdings zu beachten, daß der Ventilstößel durch eine Zuführbohrung mit einem Schmiermittel aus dem Schmiermittelkreislauf der Verbrennungskraftmaschine befüllt wird. Eine derartige Ausgestaltung bedingt durch die in Zylinderkopf angeordneten Bohrungen einen hohen Herstellungsaufwand und ist daher in wirtschaftlicher Hinsicht wenig befriedigend.Such a valve lash adjuster is known from DE-OS 31 50 083. A flexible rubber seal then forms a first check valve for sealing the reservoir for a hydraulic pressure medium. Even after the engine has been idle for a long time, the valve tappet contains the amount of pressure medium required for correct operation because the return flow of the pressure medium from the tank is blocked by the flexible rubber check valve. It should be noted, however, that the valve tappet is supplied with a lubricant from the lubricant circuit through a feed hole Internal combustion engine is filled. Such a configuration requires a high production outlay due to the bores arranged in the cylinder head and is therefore unsatisfactory in economic terms.

Der Erfindung liegt die Aufgabe zugrunde, eine Einrichtung der eingangs genannten Art derart weiterzuentwickeln, daß der erste Hohlzylinder stets mit Druckmittel gefüllt ist, selbst wenn die Ventile bei längerem Stillstand der Brennkraftmaschine in Offenstellung gehalten werden und daß zur Befüllung des Spielausgleichselement keine speziell dafür vorgesehene Ölzuführungsbohrungen im Zylinderkopf vorgesehen ist.The invention has for its object to further develop a device of the type mentioned in such a way that the first hollow cylinder is always filled with pressure medium, even if the valves are kept in the open position when the internal combustion engine is at a long standstill, and that no oil supply holes specially provided for this purpose are used to fill the play compensation element is provided in the cylinder head.

Diese Aufgabe wird mit den kennzeichnenden Merkmalen von Patentanspruch 1 gelöst. Auf vorteilhafte Ausgestaltungen nehmen die Unteransprüche bezug.This object is achieved with the characterizing features of patent claim 1. The subclaims refer to advantageous configurations.

Bei der erfindungsgemäßen hydraulischen Ventilspielausgleichseinrichtung für eine Verbrennungskraftmaschine weist das Gehäuse in zumindest einem Teilbereich einen Außendurchmesser auf, der im Bereich der Öffnung beginnend bis zum Boden verkleinert ist, wobei der Teilbereich des Gehäuses und die Führung einen in axialer Richtung keilförmigen Spalt begrenzen, der in der Ebene des Bodens offen ist. Eine Zuführung von Öl in den zweiten Hohlzylinder, der als Hochdruckraum ausgebildet ist, erfolgt im Aufwärtshub des Gehäuses dadurch, daß zwischen der zylindrischen Führung und dem im Durchmesser verkleinerten Bereich des Außendurchmessers ein Spalt gebildet ist, wodurch das Öl durch die Schmiermitteldurchtrittsöffnung, am ersten Rückschlagventil vorbei in den ersten Hohlzylinder und von dort über ein zweites Rückschlagventil in den zweiten Hohlzylinder gelangt. Bei dem zur Füllung verwendeten Öl handelt es sich um Spritzöl, das im Zylinderkopf zur Schmierung von Nockenwelle, Nocken und Stößel ohnehin vorhanden ist.In the hydraulic valve lash adjuster for an internal combustion engine according to the invention, the housing has an outer diameter in at least one partial area, which is reduced in size from the opening area to the bottom, the partial area of the housing and the guide delimiting a wedge-shaped gap in the axial direction, which in the Level of the floor is open. A supply of oil into the second hollow cylinder, which is designed as a high-pressure chamber, takes place in the upward stroke of the housing in that a gap is formed between the cylindrical guide and the reduced-diameter area of the outer diameter, as a result of which the oil passes through the lubricant passage opening at the first check valve past in the first hollow cylinder and from there via a second check valve into the second hollow cylinder. The oil used for filling is spray oil that is present in the cylinder head for the lubrication of the camshaft, cam and tappet anyway.

Ist der Aufwärtshub beendet, befindet sich das Ventil in Geschlossenstellung und die beiden Hohlzylinder weisen in axialer Richtung, durch die Druckfeder bedingt, den größtmöglichen Abstand voneinander auf. Zum Öffnen des Ventils wird das Spielausgleichselement durch eine Nocke in eine Abwärtsbewegung versetzt. Sowohl das zweite Rückschlagventil, das den zweiten Hohlzylinder vom ersten Hohlzylinder trennt, als auch das erste Rückschlagventil, das den Rückfluß aus dem ersten Hohlzylinder durch die Öffnung in Richtung Zylinderkopf sperrt, sind geschlossen. Dadurch wird einerseits eine in axialer Richtung nahezu unnachgiebige Verbindung zwischen Nockenwelle und Ventil hergestellt und andererseits bewirkt, daß zumindest der erste Hohlzylinder bei jedem Betriebszustand des Motors, auch nach längerem Stillstand vollständig mit Öl gefüllt ist. Eine Gefahr des Klapperns dadurch, daß Luft vom ersten in den zweiten Hohlzylinder gelangt, besteht nicht. Der wesentliche Vorteil ist darin zu sehen, daß die schwierig zu fertigenden Zuführungsbohrungen im Zylinderkopf, die bisher zur Versorgung der Spielausgleichselementes mit Schmiermittel benötigt wurden, vermieden werden. Die erfindungsgemäße Ausgestaltung ist in wirtschaftlicher Hinsicht besonders vorteilhaft.When the upward stroke has ended, the valve is in the closed position and the two hollow cylinders have the greatest possible distance from one another in the axial direction, due to the compression spring. To open the valve, the lash adjuster is moved downwards by a cam. Both the second check valve, which separates the second hollow cylinder from the first hollow cylinder, and the first check valve, which blocks the backflow from the first hollow cylinder through the opening in the direction of the cylinder head, are closed. As a result, on the one hand, an almost rigid connection between the camshaft and valve is established in the axial direction, and on the other hand, causes at least the first hollow cylinder to be completely filled with oil in every operating state of the engine, even after a long standstill. There is no risk of rattling as a result of air entering the second hollow cylinder from the first. The main advantage is the fact that the difficult to manufacture feed holes in the cylinder head, which were previously required to supply the lash adjuster with lubricant, are avoided. The configuration according to the invention is particularly advantageous in economic terms.

Das Gehäuse kann entlang einer Umfangslinie in allen Teilbereichen einen gleichmäßig verringerten Außendurchmesser aufweisen. Diese Gehäuseform kann besonders einfach hergestellt werden, was Vorteile bezüglich der Wirtschaftlichkeit bedingt.The housing can have a uniformly reduced outer diameter along a circumferential line in all partial areas. This form of housing can be produced in a particularly simple manner, which gives advantages in terms of economy.

Nach einer anderen Ausgestaltung ist es vorgesehen, daß das Gehäuse umfangsseitig zumindest einen segmentartig keilförmigen Abschnitt aufweist, dessen Begrenzungen den selben Außendurchmesser aufweisen wie das Gehäuse im Bereich der zylindrischen Führung. Hierbei ist von Vorteil, daß sich die Führungsfläche des Gehäuses über ihre gesamte axiale Ausdehnung in einer Führungsbuchse eine Zylinderkopfes abstützen kann. Der Verschleiß der Führungsfläche des Gehäuses, bedingt durch die Kippmomente bei der Bewegung des Gehäuses in axialer Richtung, sind dadurch vergleichsweise erringert. Nach eine bevorzugten Ausführungsform ist es vorgesehen, daß umfangsseitig jeweils rechtwinklig zueinander vier segmentartig keilförmige Abschnitte entlang des Umfangs angeordnet sind.According to another embodiment, it is provided that the housing has at least one segment-like wedge-shaped section on the circumference, the boundaries of which have the same outer diameter as the housing in the region of the cylindrical guide. The advantage here is that the guide surface of the housing can be supported on a cylinder head over its entire axial extent in a guide bush. The Wear of the guide surface of the housing, caused by the tilting moments when the housing is moved in the axial direction, is thereby reduced comparatively. According to a preferred embodiment, it is provided that four segment-like wedge-shaped sections are arranged along the circumference at right angles to one another.

Der Außendurchmesser kann kontinuierlich ineinander übergehend oder stufenförmig verkleinert sein. Die Form des Gehäuses in diesem Bereich kann den jeweiligen Gegebenheiten des Anwendungsfalles dadurch besonders gut angepaßt werden. Einige der relevanten Parameter, von denen die Spaltgröße zwischen Gehäuse und Führung abhängt, werden durch das erste Rückschlagventil, die Größe der Schmiermitteldurchtrittsöffnung sowie die geometrischen Abmessungen der Hohlzylinder gebildet.The outer diameter can be continuously merging or reduced in steps. The shape of the housing in this area can be particularly well adapted to the particular circumstances of the application. Some of the relevant parameters, on which the gap size between the housing and the guide depends, are formed by the first check valve, the size of the lubricant passage opening and the geometric dimensions of the hollow cylinder.

Gemäß einer vorteilhaften Ausgestaltung ist es vorgesehen, daß im Gehäuse innenseitig eine Trennwand festgelegt ist, die mit dem Boden einen ringförmigen Kanal begrenzt und daß der Kanal mit dem ersten Hohlzylinder flüssigkeitsleitend verbunden ist. Die Trennwand, die das erste Rückschlagventil, das beispielsweise aus einem elastisch nachgiebigen Werkstoff besteht, in radialer Richtung im Bereich der Schmiermitteldurchtrittsöffnung des Gehäuses fixiert, gewährleistet gute Gebrauchseigenschaften bei kompakten Abmessungen des Spielausgleichselementes.According to an advantageous embodiment, it is provided that a partition is defined on the inside in the housing, which delimits an annular channel with the bottom, and that the channel is connected to the first hollow cylinder in a liquid-conducting manner. The partition wall, which fixes the first check valve, which consists for example of an elastically resilient material, in the radial direction in the region of the lubricant passage opening of the housing, ensures good performance characteristics with compact dimensions of the play compensation element.

Die Trennwand wird auf der in axialer Richtung dem Boden abgewandten Seite von der dem Kanal zugewandten Stirnseite des ersten Hohlzylinders anliegend berührt und von dem zweiten Hohlzylinder nur bei größtmöglicher Einfederung. Als Druckbegrenzung im ersten Hohlzylinder kann die Stirnseite des ersten Hohlzylinders und/oder die Gegenfläche der Trennwand eine Rautiefe von wenigstens 1 µm aufweisen. Bei Überschreitung eines bestimmten Druckes im ersten Hohlzylinder kann die darin enthaltene Flüssigkeitsmenge in Form einer Leckage zwischen dem ersten Hohlzylinder und der Trennwand entweichen. Eine weitere Leckage, die während der bestimmungsgemäßen Verwendung der Ventilspielausgleichseinrichtung auftritt, entsteht zwischen der Außenumfangsfläche des ersten Hohlzylinders und der Innenfläche des zweiten Hohlzylinders. Dadurch, daß diese beiden Teile in axialer Richtung beweglich ineinander geführt sind, und der zweite Hohlzylinder als Hochdruckraum ausgebildet ist, wird die Passung zwischen den beiden Teilen von Schmiermittel durchdrungen. Diese geringe Menge bewirkt eine einwandfreie Schmierung zwischen den beiden Teilen und einen verschleißarmen Betrieb sowie einen permanenten Austausch und eine Auffrischung des Schmiermittels.The partition wall is touched on the side facing away from the bottom in the axial direction by the end face of the first hollow cylinder facing the channel and only by the second hollow cylinder with the greatest possible deflection. The end face of the first hollow cylinder and / or the counter surface of the partition can be a pressure limitation in the first hollow cylinder Have a roughness depth of at least 1 µm. If a certain pressure in the first hollow cylinder is exceeded, the amount of liquid contained therein can escape in the form of a leak between the first hollow cylinder and the partition. Another leak that occurs during the intended use of the valve lash adjuster arises between the outer peripheral surface of the first hollow cylinder and the inner surface of the second hollow cylinder. The fact that these two parts are movably guided one inside the other in the axial direction and the second hollow cylinder is designed as a high-pressure chamber, the fit between the two parts is penetrated by lubricant. This small amount ensures perfect lubrication between the two parts and low-wear operation, as well as permanent replacement and refreshing of the lubricant.

Der zweite Hohlzylinder kann während der bestimmungsgemäßen Verwendung durch ein Befestigungselement unverlierbar, aber axial verschieblich im Gehäuse angeordnet sein. Das Befestigungselement gewährleistet eine einfache Montage des Spielausgleichselementes im Ventiltrieb einer Verbrennungskraftmaschine. Das Befestigungselement kann beispielsweise in einer Nut entlang der innenseitigen Umfangsfläche des Gehäuses angeordnet sein und neben dem zweiten Hohlzylinder auch die Trennwand mit dem darin angeordneten ersten Rückschlageventil in ihrer radialen Richtung fixieren.The second hollow cylinder can be captively, but axially displaceably arranged in the housing during use as intended. The fastening element ensures simple assembly of the play compensation element in the valve train of an internal combustion engine. The fastening element can, for example, be arranged in a groove along the inner circumferential surface of the housing and, in addition to the second hollow cylinder, can also fix the partition wall with the first check valve arranged therein in its radial direction.

Zur einfacheren Montage und Demontage des Befestigungselementes sowie zum Ableiten der durch Leckage entstandenen Schmiermittelverluste aus den Hohlzylindern kann dieses mit Ausnehmungen in Richtung des Brennraumes versehen sein.For easier assembly and disassembly of the fastening element and for deriving the lubricant losses caused by leakage from the hollow cylinders, this can be provided with recesses in the direction of the combustion chamber.

Gemäß einer weiteren vorteilhaften Ausgestaltung können die Trennwand und das Befestigungselement einstückig ausgebildet sein und aus polymerem Werkstoff bestehen. Sowohl im Hinblick auf eine weiter vereinfachte Montage als auch im Hinblick auf eine möglichst geringe zu beschleunigende Masse des Spielausgleichselementes ist dies von Vorteil. Zur weiteren Verbesserung der Gebrauchseigenschaften sowie zur weiteren Verringerung des Verschleißes kann das Befestigungselement aus einem Werkstoff mit besonders geringem Reibungskoeffizienten bestehen oder mit einer Oberflächenbeschichtung versehen sein, die eine geringe Reibung zwischen den relativ zueinander bewegten Teilen gewährleistet.According to a further advantageous embodiment, the partition and the fastening element can be formed in one piece and consist of polymeric material. This is advantageous both in terms of a further simplified assembly and in terms of the smallest possible mass of the play compensation element to be accelerated. To further improve the usage properties and to further reduce wear, the fastening element can consist of a material with a particularly low coefficient of friction or can be provided with a surface coating which ensures low friction between the parts moving relative to one another.

Eine Ventilspielausgleichseinrichtung der erfindungsgemäßen Art kann in Zylinderköpfen von Verbrennungskraftmaschinen zur Anwendung gelangen, die keine separaten Leitungen zur Befüllung des Spielausgleichselementes aufweisen.A valve lash adjuster of the type according to the invention can be used in cylinder heads of internal combustion engines which do not have separate lines for filling the lash adjuster.

Der Gegenstand der vorliegenden Erfindung wird nachfolgend anhand der Zeichnungen weiter erläutert. Diese zeigen die zu berücksichtigenden Einzelkomponenten teilweise in schematischer Darstellung.The object of the present invention is explained in more detail below with reference to the drawings. These show the individual components to be taken into account, partly in a schematic representation.

Es zeigen:

  • Fig. 1 die hydraulische Ventilspielausgleichseinrichtung, wobei die Trennwand und das Befestigungselement zweiteilig ausgebildet sind.
  • Fig. 2 eine andere Ausgestaltung der hydraulischen Ventilspielausgleichseinrichtung, bei der die Trennwand und das Befestigungselement einstückig ausgebildet sind.
  • Fig. 3 zeigt eine Darstellung der umfangsseitig angeordneten, segmentartig keilförmigen Abschnitte.
Show it:
  • Fig. 1 shows the hydraulic valve lash adjuster, the partition and the fastener are formed in two parts.
  • Fig. 2 shows another embodiment of the hydraulic valve lash adjuster, in which the partition and the fastening element are integrally formed.
  • 3 shows a representation of the circumferentially arranged, segment-like wedge-shaped sections.

In Fig. 1 sind zwei Belastungszustände der hydraulischen Ventilspielausgleichseinrichtung dargestellt. Im linken Teil der Darstellung begrenzt der zweite Hohlzylinder 4 das geringste Volumen des Hochdruckraumes und liegt mit seiner in axialer Richtung geöffneten Stirnfläche an der Trennwand 8 an. Im rechten Teil der Darstellung weist der Hochdruckraum, der im wesentlichen von dem zweiten Hohlzylinder 4 begrenzt ist, sein größtes Volumen auf. Der zweite Hohlzylinder 4 liegt in axialer Richtung mit einem Vorsprung an einer Anschlagfläche des Befestigungselementes 10 an. Der im linken Teil dargestellte Belastungszustand tritt beispielsweise dann ein, wenn das Spielausgleichselement 1 bei abgeschalteter Verbrennungskraftmaschine längerer Zeit unter axialer Belastung zwischen einem hier nicht dargestellten Nocken und einem geöffneten Ventil angeordnet ist. In diesem Fall entweicht über die Passung zwischen dem ersten Hohlzylinder 3 und dem zweiten Hohlzylinder 4 das im Hochdruckraum befindliche Öl allmählich und bewirkt gleichzeitig eine allmähliche Lageveränderung des angrenzenden Ventiles in Richtung Geschlossenstellung. Diese Verschiebung des zweiten Hohlzylinders relativ zum ortsfesten ersten Hohlzylinder 3 und dem Gehäuse 6 ist dann beendet, wenn dieser wie beispielsweise hier dargestellt an der Trennwand 8 anliegt.In Fig. 1 two load conditions of the hydraulic valve lash adjuster are shown. In the left part of the illustration, the second hollow cylinder 4 delimits the smallest volume of the high-pressure space and, with its end face open in the axial direction, lies against the partition 8. In the right part of the illustration, the high-pressure space, which is essentially delimited by the second hollow cylinder 4, has its largest volume. The second hollow cylinder 4 bears in the axial direction with a projection on a stop surface of the fastening element 10. The load state shown in the left part occurs, for example, when the lash adjuster 1 is arranged for a long time with the internal combustion engine switched off under axial load between a cam (not shown here) and an open valve. In this case, the oil in the high-pressure chamber gradually escapes via the fit between the first hollow cylinder 3 and the second hollow cylinder 4 and at the same time brings about a gradual change in position of the adjacent valve in the direction of the closed position. This displacement of the second hollow cylinder relative to the stationary first hollow cylinder 3 and the housing 6 is ended when the latter rests on the partition 8, as shown here, for example.

Im rechten Teil der Darstellung ist ein Belastungszustand des Spielausgleichselementes 1 dargestellt, wie er sich während des Betriebes der Verbrennungskraftmaschine ergibt. Ohne von außen angreifende Belastung, also im oberen Todpunkt des Spielausgleichselementes 1 bewegt die Druckfeder 5 den ersten 3 und zweiten Hohlzylinder 4 voneinander weg, bis der zweite Hohlzylinder 4, der relativ beweglich ist, an dem Befestigungselement 10 zu Anlage gelangt. In diesem Stadium, also bei entspanntem Hochdruckraum, kann Schmiermittel, das sich im ersten Hohlzylinder und im damit flüssigkeitsleitend verbundenen Kanal 9 befindet, über das zweite Rückschlagventil 13 in den Hochdruckraum nachströmen und so durch Leckage verdrängtes Flüssigkeitsvolumen auffüllen. Die Befüllung des Spielausgleichselementes 1 erfolgt über einen Spalt 12, der durch das Gehäuse 6 und die zylindrische Führung 2 gebildet ist. Dabei ist es vorgesehen, daß das Gehäuse 6 einen Außendurchmesser aufweist, der im Bereich der Öffnung 6.2 beginnend in Richtung des Bodens 6.1 verkleinert ist.In the right part of the illustration, a load state of the lash adjuster 1 is shown as it results during the operation of the internal combustion engine. Without external loads, i.e. at the top dead center of the game compensation element 1, the compression spring 5 moves the first 3 and second hollow cylinders 4 away from one another until the second hollow cylinder 4, which is relatively movable, comes to bear against the fastening element 10. At this stage, that is, when the high-pressure chamber is relaxed, lubricant which is in the first hollow cylinder and in the channel 9 connected to it in a liquid-conducting manner can flow into the high-pressure chamber via the second check valve 13 and thus fill up with liquid volume displaced by leakage. The play compensation element 1 is filled via a gap 12 which is formed by the housing 6 and the cylindrical guide 2. It is provided that the housing 6 has an outer diameter which is reduced in the area of the opening 6.2 starting in the direction of the bottom 6.1.

Zur Funktion ist folgenden auszuführen: Ausgangspunkt des Funktionsablaufes ist die Stellung, in der das Ventil der Brennkraftmaschine vollständig geöffnet ist, d.h. der Nocken hat das gesamte Spielausgleichselement 1 in seinen unteren Totpunkt gebracht. Oberhalb des Gehäuses 6 und an der Wandung der Führung 2 befindet sich Öl, das als Spritzöl zur Schmierung der Nockenwelle, der Nocken und der Lauffläche zwischen Nocken und Gehäuse 6 benötigt wird. Dieses Öl wird bei der nun folgenden Aufwärtsbewegung des Gehäuses 6 in den keilförmigen Spalt 12 gedrückt und über die Schmiermitteldurchtrittsöffnungen 6.2 an dem ersten Rückschlagventil 7 vorbei in den Kanal 9 und den ersten Hohlzylinder 3 bewegt. Die Aufwärtsbewegung des Spielausgleichselementes 1 gelangt im oberen Todpunkt zum Stillstand. In diesem Fall ist das Ventil der Brennkraftmaschine geschlossen. Danach bewegt der Nocken das gesamte Spielausgleichselement 1 wieder abwärts zur Öffnung des Ventils. Dabei verhindert das erste Rückschlagventil 7 das Rückströmen des Öls aus dem ersten Hohlzylinder 3 und dem Kanal 9 zurück durch die Schmiermitteldurchtrittsöffnung 6.2 in den keilförmigen Spalt 12. Im betriebsbedingten, hier rechts dargestellten Zustand werden die Verluste durch Leckage im Hochdruckraum durch ein Nachströmen des Schmiermittels aus dem ersten Hohlzylinder 3 und dem Kanal 9 ausgeglichen, so daß eine weitgehend unnachgiebige Verbindung zwischen Nocken und Ventil entsteht. Auch bei Stillstand des Motors verhindert das erste Rückschlagventil 7 daß der erste Hohlzylinder 3 sowie der Kanal 9 mit zunehmender Zeit leerlaufen. Damit ist sichergestellt, daß sich im Kanal 9 sowie im ersten Hohlzylinder 3 immer ausreichend Öl befindet zur Versorgung des Hochdruckraumes innerhalb des zweiten Hohlzylinders 4.The function is as follows: The starting point of the functional sequence is the position in which the valve of the internal combustion engine is fully open, ie the cam has brought the entire play compensation element 1 to its bottom dead center. Above the housing 6 and on the wall of the guide 2 there is oil which is required as spray oil for lubricating the camshaft, the cams and the running surface between the cam and the housing 6. During the now upward movement of the housing 6, this oil is pressed into the wedge-shaped gap 12 and moved over the lubricant passage openings 6.2 past the first check valve 7 into the channel 9 and the first hollow cylinder 3. The upward movement of the play compensation element 1 comes to a standstill at the top dead center. In this case, the valve of the internal combustion engine is closed. The cam then moves the entire play compensation element 1 downward again to open the valve. The first check valve 7 prevents the oil from flowing back out of the first hollow cylinder 3 and the channel 9 back through the lubricant passage opening 6.2 into the wedge-shaped gap 12. In the operational condition, shown here on the right, the losses due to leakage in the high-pressure chamber are caused by a subsequent flow of the lubricant the first hollow cylinder 3 and the channel 9 equalized, so that a largely rigid connection between the cam and valve is formed. Even when the engine is at a standstill, the first check valve 7 prevents the first hollow cylinder 3 and the channel 9 from running empty with increasing time. This ensures that there is always sufficient oil in the channel 9 and in the first hollow cylinder 3 to supply the high-pressure space within the second hollow cylinder 4.

Die Gefahr, daß bei Inbetriebnahme der Verbrennungskraftmaschine Luft in den Hochdruckraum einströmt, besteht damit nicht.There is therefore no risk that air will flow into the high-pressure chamber when the internal combustion engine is started up.

In Fig. 2 ist eine hydraulische Ventilspielausgleichseinrichtung dargestellt, die der in Fig. 1 sehr ähnlich ist. Sie unterscheidet sich primär dadurch, daß die Trennwand 8 und das Befestigungselement 10 einstückig ausgebildet sind und aus polymerem Werkstoff bestehen. Die Funktionsweise ist der vorstehend beschriebenen ähnlich.In Fig. 2, a hydraulic valve lash adjuster is shown, which is very similar to that in Fig. 1. It differs primarily in that the partition 8 and the fastening element 10 are formed in one piece and consist of polymeric material. The mode of operation is similar to that described above.

In Fig.3 ist eine Ventilspielausgleichseinrichtung in perspektivischer Darstellung gezeigt, bei der die Verkleinerung des Außendurchmessers in Richtung des Bodens 6.1 des Gehäuses 6 nur segmentartig ausgeführt ist. Die segmentartigen Abschnitte 12.1 weisen im Bereich ihrer Begrenzungen einen derartigen Außendurchmesser auf, daß sich umfangsseitig zwischen den keilförmigen Abschnitten 12.1 ein durchgehend konstanter Außendurchmesser in axialer Richtung des Gehäuses ergibt. Neben guten Gebrauchseigenschaften ist die Gefahr einer Verkantung in einem hier nicht dargestellten Zylinderkopf bei axialer Bewegung durch die vergleichsweise große Ausdehnung des Gehäuses 6 in axialer Richtung deutlich verringert.In Figure 3, a valve lash adjuster is shown in perspective, in which the reduction of the outer diameter in the direction of the bottom 6.1 of the housing 6 is carried out only in segments. The segment-like sections 12.1 have such an outer diameter in the area of their boundaries that there is a continuously constant outer diameter in the axial direction of the housing between the wedge-shaped sections 12.1. In addition to good performance properties, the risk of tilting in a cylinder head (not shown here) during axial movement is significantly reduced by the comparatively large expansion of the housing 6 in the axial direction.

Der wesentliche Vorteil der Erfindung ist in der Ölzuführung zu sehen, die während der Aufwärtsbewegung des Spielausgleichselementes 1 selbsttätig durch den im Spalt 12 entstehenden Druck erfolgt. Eine wesentliche Vereinfachung bei der Konstruktion und Herstellung der Zylinderköpfe und Zylinderblöcke der Verbrennungskraftmaschine wird hierdurch bedingt.The main advantage of the invention can be seen in the oil supply, which takes place automatically during the upward movement of the play compensation element 1 by the pressure arising in the gap 12. This results in a significant simplification in the design and manufacture of the cylinder heads and cylinder blocks of the internal combustion engine.

Claims (12)

  1. A hydraulic valve clearance compensating device for an internal combustion engine, in which a clearance compensating element (1) is movable up and down in the axial direction in a cylindrical guide (2), comprising a first (3) and a second hollow cylinder (4) which are sealed off relative to one another and are supported in an axially elastic manner on one another by a compression spring (5) and are surrounded concentrically by an essentially cup-shaped housing (6) with a flat top (6.1) and with at least one circumferentially arranged lubricant opening (6.2), the first hollow cylinder (3) and the lubricant opening (6.2) being connected to one another in a fluid-carrying manner, and the lubricant opening (6.2) being assigned, on the side facing the hollow cylinders (3, 4), a first non-return valve (7), which allows the passage of lubricant through the opening (6.2) in the direction of the first hollow cylinder (3) and blocks backflow from the first hollow cylinder (3) through the opening (6.2), characterised in that, in at least a partial area, the housing (6) has an outside diameter which, from the area of the opening (6.2) to the top (6.1), is reduced, and in that the partial area of the housing (6) and the guide (2) delimit an axially wedge-shaped gap (12) which is open in the plane of the top (6.1).
  2. A valve clearance compensating device according to claim 1, characterised in that the housing (6) has a constantly reduced outside diameter along a circumferential line in all partial areas.
  3. A valve clearance compensating device according to claim 1, characterised in that, on the circumference, the housing (6) has at least one section (12.1) in the form of a wedge-shaped segment, the boundaries of which have the same outside diameter as the housing (6) in the area of the cylindrical guide.
  4. A valve clearance compensating device according to any of claims 1 to 3, characterised in that the outside diameter is reduced continuously with a continuous transition.
  5. A valve clearance compensating device according to any of claim 1 to 3, characterised in that the outside diameter is reduced stepwise.
  6. A valve clearance compensating device according to any of claims 1 to 5, characterised in that fixed internally in the housing (6) is a dividing wall (8) which, together with the top (6.1), delimits an annular passage (9) which is connected in a fluid-carrying manner to the first hollow cylinder (3).
  7. A valve clearance compensating device according to claim 6, characterised in that the end face of the first hollow cylinder (3), which face faces the passage (9), touches the dividing wall (8) on the side facing away axially from the top (6.1), resting against it, while the second hollow cylinder (4) touches it only at maximum deflection.
  8. A valve clearance compensating device as claimed in claim 7, characterised in that the end face of the first hollow cylinder (3) and/or the corresponding surface of the dividing wall (8) has a peak-to-valley height of at least 1 µm.
  9. A valve clearance compensating device as claimed in any of claims 1 to 8, characterised in that, during its use as intended, the second hollow cylinder (4) is arranged in a manner held captive by a securing element (10) but axially displaceable in the housing (6).
  10. A valve clearance compensating device according to claim 9, characterised in that the securing element (10) has at least one recess (11) in the direction of the combustion chamber.
  11. A valve clearance compensating device according to any of claims 6 to 10, characterised in that the dividing wall (18) and the securing element (10) are of integral design.
  12. A valve clearance compensating device according to any of claims 1 to 11, characterised by use in a cylinder head which does not have a separate conduit for the filling of the clearance compensating (1).
EP92103236A 1991-07-24 1992-02-26 Hydraulic valve lash adjuster for internal combustion engine Expired - Lifetime EP0525284B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4124484A DE4124484C1 (en) 1991-07-24 1991-07-24
DE4124484 1991-07-24

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EP0525284A1 EP0525284A1 (en) 1993-02-03
EP0525284B1 true EP0525284B1 (en) 1994-08-24

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EP92103236A Expired - Lifetime EP0525284B1 (en) 1991-07-24 1992-02-26 Hydraulic valve lash adjuster for internal combustion engine

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US (1) US5183016A (en)
EP (1) EP0525284B1 (en)
JP (1) JP2584569B2 (en)
AT (1) ATE110440T1 (en)
BR (1) BR9202047A (en)
CA (1) CA2074414C (en)
DE (2) DE4124484C1 (en)
ES (1) ES2059169T3 (en)
MX (1) MX9204313A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19503699A1 (en) * 1995-02-04 1996-08-08 Schaeffler Waelzlager Kg First filling of hydraulic valve drive tappet with hydraulic oil
DE19617669A1 (en) * 1996-05-03 1997-11-06 Schaeffler Waelzlager Kg Hydraulic lash adjuster for a valve train of an internal combustion engine
GB9707387D0 (en) * 1997-04-11 1997-05-28 Clancy Limited G Hydraulic tappet assembly
KR100486846B1 (en) * 1997-11-29 2005-08-24 국방과학연구소 Check Valve Structure for Oil Filling of Line Array Sound Detector
DE102006037816A1 (en) * 2006-08-12 2008-02-14 Schaeffler Kg Valve lift transmission device for actuating combustion engine gas-exchange valve, has compensating space connected via beads in recessed position of valve play compensator
DE102019105607A1 (en) * 2019-03-06 2020-01-09 Schaeffler Technologies AG & Co. KG Hydraulic support element for a valve train of an internal combustion engine

Citations (1)

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Publication number Priority date Publication date Assignee Title
DE8902780U1 (en) * 1989-03-08 1989-04-20 INA Wälzlager Schaeffler KG, 8522 Herzogenaurach Self-adjusting hydraulic valve tappet

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US2595583A (en) * 1949-09-26 1952-05-06 Johnson Products Inc Oil supply for hydraulic tappets
IT7853889V0 (en) * 1978-11-15 1978-11-15 Fiat Spa HYDRAULIC PUNTERS WITH AUTOMATIC BACKLASH FOR INTERNAL COMBUSTION ENGINES WITH CAMSHAFTS IN THE HEAD
US4392462A (en) * 1980-12-22 1983-07-12 Stanadyne, Inc. Inverted bucket tappet with seal
US4463713A (en) * 1981-09-02 1984-08-07 Riv-Skf Officine Di Villar Perosa S.P.A. Hydraulic tappet with automatic taking up of the clearance for endothermic engines
IT8453964V0 (en) * 1984-10-25 1984-10-25 Fiat Auto Spa HYDRAULIC VALVE IN PARTICULAR FOR A HYDRAULIC TAPPET

Patent Citations (1)

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Publication number Priority date Publication date Assignee Title
DE8902780U1 (en) * 1989-03-08 1989-04-20 INA Wälzlager Schaeffler KG, 8522 Herzogenaurach Self-adjusting hydraulic valve tappet

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JPH05195724A (en) 1993-08-03
MX9204313A (en) 1992-11-01
ATE110440T1 (en) 1994-09-15
JP2584569B2 (en) 1997-02-26
CA2074414C (en) 1994-10-25
BR9202047A (en) 1993-10-05
DE4124484C1 (en) 1993-01-14
DE59200407D1 (en) 1994-09-29
CA2074414A1 (en) 1993-01-25
ES2059169T3 (en) 1994-11-01
US5183016A (en) 1993-02-02
EP0525284A1 (en) 1993-02-03

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