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EP0639695B1 - Valve stem seal - Google Patents

Valve stem seal Download PDF

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Publication number
EP0639695B1
EP0639695B1 EP19940107573 EP94107573A EP0639695B1 EP 0639695 B1 EP0639695 B1 EP 0639695B1 EP 19940107573 EP19940107573 EP 19940107573 EP 94107573 A EP94107573 A EP 94107573A EP 0639695 B1 EP0639695 B1 EP 0639695B1
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EP
European Patent Office
Prior art keywords
valve stem
stem seal
sealing ring
cylindrical section
sealing
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
EP19940107573
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German (de)
French (fr)
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EP0639695A1 (en
Inventor
Claude Caillaud
Laurent Salagnac
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Carl Freudenberg KG
Original Assignee
Carl Freudenberg KG
Priority date (The priority date 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 date listed.)
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Classifications

    • 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
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L3/08—Valves guides; Sealing of valve stem, e.g. sealing by lubricant

Definitions

  • the invention relates to a valve stem seal comprising a rigid tube which is delimited at one end by a first cylinder section and at the other end by a radially outwardly projecting flange, a sealing ring being inserted in the cylinder section in a self-locking manner, one in the axial direction has protruding, radially elastic sealing lip which can be brought into engagement with the valve stem.
  • valve stem seal is known from EP A 0 380 770. It is pushed onto the end of a tubular valve guide for intended use, the sealing lip coming into sealing contact with the valve stem and a further seal with the outer circumference of the valve guide.
  • the sealing ring is delimited on the outside by a stiffening ring, which is inserted so tightly into the cylinder section of the deformation-resistant tube that it can be handled, stored, transported, assembled and used relatively easily without avoiding a relative displacement of the two parts with respect to one another. In order to meet these conditions, assembly requires the precise observance of fine manufacturing tolerances and the use of large press-in forces.
  • the latter are of the order of magnitude of 1000 to 2000 N if the play between the outer circumference of the stiffening ring and the inner circumference of the cylinder section is 30 to 60 ⁇ m. Greater forces cannot be absorbed by the two parts when they are put into one another if damage is to be avoided. Smaller forces are sufficient if the manufacturing tolerances are increased. However, it must then be taken into account that not the problem-free use of the Valve stem seals provide the desired tight fit. For this reason, it is customary to take special care in the manufacture of the pipe and the stiffening ring and to calibrate the surfaces that come into contact with one another during assembly to an exact dimension. This inevitably results in very high manufacturing costs.
  • the object of the invention is to further develop such a valve stem seal in such a way that a reliable fixing of the two parts into one another after assembly is ensured with simplified manufacture.
  • the valve stem seal according to the invention should in particular allow the tolerances to be observed during production to be increased while avoiding other disadvantages.
  • the ribs are evenly distributed in the circumferential direction.
  • the deformation forces resulting when the two parts are joined together are accordingly also uniformly distributed in the circumferential direction.
  • the implementation of the joining process is significantly simplified.
  • the valve stem seal can then be used and installed as a self-contained unit.
  • the ribs expediently have a triangular profile, which is arranged in such a way that the base reinforces the cylinder section or sealing ring on which the respective rib is arranged, and the tip touches the mating surface after assembly.
  • the height of the ribs is a few hundredths of a millimeter more than the difference between half the inner diameter of the cylinder section and half the outer diameter of the sealing ring.
  • valve stem seal according to the invention is that both the cylinder section and the stiffening ring can have large manufacturing inaccuracies without the resultant impairment of the resulting adhesive connection after the two parts have been inserted into one another.
  • the cylinder section can be delimited at the end facing away from the first flange by a second, radially inwardly projecting flange. This further increases the security against a breakup of the connection between the two parts.
  • the cylinder section and the second flange overlap the sealing ring and the sealing lip over their entire axial length and that the sealing lip is freely movable in the radial direction.
  • the sealing lip is excellently protected from damage by the cylinder section or second flange surrounding it, which is of great advantage during manufacture, storage, transport and assembly of the valve stem seal.
  • valve stem seal is preferably used in a vertical position, the spray oil present in the area of the valve control reaching the space between the cylinder section, the sealing lip and the valve stem and building up.
  • the pent-up oil can linger here for a long time even when the internal combustion engine is stopped, which means that it is immediately available for lubrication when it is restarted.
  • the wear of the valve stem seal according to the invention is thereby reduced and its service life is significantly improved.
  • the sealing ring expediently consists of a stiffening ring, for example made of metal or plastic, and an elastic sealing element.
  • the latter can, in one piece, merge into one another at least one sealing lip which can be brought into engagement with the valve stem and at least one sealing rib which can be brought into engagement with the valve guide.
  • the latter is expediently molded onto the stiffening ring in such a way that after the valve stem seal has been pushed onto the outer circumference of a valve guide, there is a radial compression of the sealing rib between the valve guide and the stiffening ring.
  • the ribs 13 extend parallel to the axis 1a of the valve stem seal.
  • the surfaces delimiting them in the circumferential direction intersect one another in radially inward-pointing edges at an angle of 72 °. Depending on the requirements in the individual case, the angle can optionally be chosen to be larger or smaller.
  • the sealing ring is enclosed in the area touched by the ribs 13 by a metallic stiffening ring 11.
  • the stiffening ring 11 has half the outer diameter r in the region engaging the ribs (FIG. 2). In the usual sizes of motor vehicle engines, this is a few hundredths of a millimeter larger than the radius of an imaginary cylinder surface on which the radially inward-pointing tips of the ribs 13 are arranged in new and undeformed condition.
  • the sealing lip 8 is enclosed by the cylinder section 3 and the second flange 4 of the deformation-resistant tube 6. It is thereby protected from damage in an excellent manner, which is of considerable advantage during manufacture, storage and assembly. Nevertheless, the sealing lip 8 is also extremely mobile in the radial direction during the intended use, which is of great advantage for achieving a good sealing result.
  • the sealing lip 8 is provided on the outside with a circumferential groove in which a pressure spring 9 is embedded.
  • the deformation-resistant tube 1 has between the cylinder section 3 and the first flange 2 in a partial area a conical in the direction of the first flange 2 an enlarged inner diameter.
  • the insertion of the sealing ring 7 from the direction of the first flange 2 is greatly facilitated.
  • the sealing element 10, comprising the sealing lip 8, of the sealing ring 7 is made of rubber in the exemplary embodiment shown. Other materials used in this field can also be used in relation to its production.
  • the stiffening ring of the sealing ring 7 has a larger outside diameter 13 in the area opposite the cylinder section 3 than in the partial area 11 adjoining in the direction of the first flange 2.
  • the press-in forces required for inserting the sealing ring 7 into the deformation-resistant tube 6 are therefore due to that absolutely necessary measure reduced.
  • During the insertion there is a plastic deformation of the edges of the ribs 13 pointing inwards in the radial direction. This occurs only to the extent that the stiffening ring 11 is actually pressed into the deformation-resistant tube 6.
  • the press-in process was stopped before the ribs were completely deformed in the axial direction.
  • a step 15 has been preserved, which prevents the sealing ring 7 from being displaced further towards the second flange 4 during assembly or use of the valve stem seal and from reaching a point at which its function is impaired.
  • a further cylindrical portion of the rigid tube 1 is present between the hollow-conical portion 5 of the rigid tube and the first flange 2.
  • the first flange 2 also serves to support the valve spring on a cylinder head, not shown, of an internal combustion engine and protects it from damage by the Valve spring. It preferably includes the tube 1 from a deep-drawn sheet steel.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Sealing With Elastic Sealing Lips (AREA)
  • Multiple-Way Valves (AREA)

Description

Die Erfindung betrifft eine Ventilschaftdichtung, umfassend ein verformungssteifes Rohr, das an dem einen Ende durch einen ersten Zylinderabschnitt und an dem anderen Ende durch einen radial nach außen vorstehenden Flansch begrenzt ist, wobei in den Zylinderabschnitt ein Dichtring selbsthemmend engefügt ist, der eine in axialer Richtung vorstehende, radialelastische Dichtlippe aufweist, die mit dem Ventilschaft in Eingriff bringbar ist.The invention relates to a valve stem seal comprising a rigid tube which is delimited at one end by a first cylinder section and at the other end by a radially outwardly projecting flange, a sealing ring being inserted in the cylinder section in a self-locking manner, one in the axial direction has protruding, radially elastic sealing lip which can be brought into engagement with the valve stem.

Eine solche Ventilschaftdichtung ist aus der EP A 0 380 770 bekannt. Sie wird zur bestimmungsgemäßen Verwendung auf das Ende einer rohrförmig gestalteten Ventilführung aufgeschoben, wobei die Dichtlippe mit dem Ventilschaft und eine weitere Dichtung mit dem Außenumfang der Ventilführung in dichtende Anlageberührung gelangt. Der Dichtring ist auf der Außenseite durch einen Versteifungsring begrenzt, der so fest sitzend in den Zylinderabschnitt des verformungssteifen Rohres eingefügt ist, daß dieses unter Vermeidung einer Relativverlagerung der beiden Teile in bezug zueinander relativ problemlos gehandhabt, gelagert, transportiert, montiert und verwendet werden kann. Das Zusammenfügen erfordert zur Erfüllung dieser Bedingungen die präzise Einhaltung feiner Herstelltoleranzen sowie die Anwendung großer Einpreßkräfte. Letztere liegen in der Größenordnung von 1000 bis 2000 N, wenn das Spiel zwischen dem Außenumfang des Versteifungsringes und dem Innenumfang des Zylinderabschnitts 30 bis 60 µm beträgt. Größere Kräfte können beim Ineinanderfügen der beiden Teile nicht von diesen aufgenommen werden, wenn Beschädigungen vermieden werden sollen. Kleinere Kräfte reichen aus, wenn die Herstelltoleranzen vergrößert werden. Es muß dann allerdings damit gerechnet werden, daß sich nicht der für eine problemlose Verwendung der Ventilschaftdichtungen erwünschte feste Sitz ergibt. Es ist aus diesem Grunde üblich, bei der Herstellung des Rohres und des Versteifungsringes besondere Sorgfalt walten zu lassen und die während der Montage miteinander in Eingriff gelangenden Flächen auf ein genaues Maß zu kalibrieren. Dabei ergeben sich zwangsläufig sehr hohe Herstellkosten.Such a valve stem seal is known from EP A 0 380 770. It is pushed onto the end of a tubular valve guide for intended use, the sealing lip coming into sealing contact with the valve stem and a further seal with the outer circumference of the valve guide. The sealing ring is delimited on the outside by a stiffening ring, which is inserted so tightly into the cylinder section of the deformation-resistant tube that it can be handled, stored, transported, assembled and used relatively easily without avoiding a relative displacement of the two parts with respect to one another. In order to meet these conditions, assembly requires the precise observance of fine manufacturing tolerances and the use of large press-in forces. The latter are of the order of magnitude of 1000 to 2000 N if the play between the outer circumference of the stiffening ring and the inner circumference of the cylinder section is 30 to 60 µm. Greater forces cannot be absorbed by the two parts when they are put into one another if damage is to be avoided. Smaller forces are sufficient if the manufacturing tolerances are increased. However, it must then be taken into account that not the problem-free use of the Valve stem seals provide the desired tight fit. For this reason, it is customary to take special care in the manufacture of the pipe and the stiffening ring and to calibrate the surfaces that come into contact with one another during assembly to an exact dimension. This inevitably results in very high manufacturing costs.

Der Erfindung liegt die Aufgabe zugrunde, eine solche Ventilschaftdichtung derart weiterzuentwickeln, daß bei einer vereinfachten Herstellbarkeit eine zuverlässige Festlegung der beiden Teile ineinander nach dem Zusammenfügen gewährleistet ist. Die erfindungsgemäße Ventilschaftdichtung soll es zur Erreichung dieses Zieles insbesondere gestatten, die bei der Herstellung einzuhaltenden Toleranzen unter Vermeidung anderer Nachteile zu vergrößern.The object of the invention is to further develop such a valve stem seal in such a way that a reliable fixing of the two parts into one another after assembly is ensured with simplified manufacture. In order to achieve this goal, the valve stem seal according to the invention should in particular allow the tolerances to be observed during production to be increased while avoiding other disadvantages.

Diese Aufgabe wir erfindungsgemäß bei einer Ventilschaftdichtung der eingangs genannten Art dadurch gelöst, daß auf dem Zylinderabschnitt radial in Richtung des Dichtrings und/oder auf dem Dichtring radial in Richtung des Zylinderabschnitts vorstehende, in Umfangsrichtung verteilte Rippen vorgesehen sind und daß der Dichtring und der Zylinderabschnitt einander nur im Bereich der Rippen berühren. Die sich beim Ineinanderfügen der beiden Teile ineinander ergebenden plastischen und/oder elastischen Verformungen sind auf den Bereich der Rippen beschränkt. Die für das Einfügen des Dichtringes in das verformungssteife Rohr benötigten Einpreßkräfte sind dadurch deutlich reduziert. Dennoch wird nach dem Zusammenfügen der Teile ein so zuverlässiger Preßsitz der Teile ineinander erhalten, daß sich während der Montage und der bestimmungsgemäßen Verwendung zwischen diesen keine Relativverlagerung ergeben kann.This object is achieved according to the invention in the case of a valve stem seal of the type mentioned at the outset in that on the cylinder section radially in the direction of the sealing ring and / or on the sealing ring radially in the direction of the cylinder section protruding ribs distributed in the circumferential direction are provided and that the sealing ring and the cylinder section each other touch only in the area of the ribs. The plastic and / or elastic deformations which result when the two parts are fitted into one another are limited to the region of the ribs. This significantly reduces the press-in forces required to insert the sealing ring into the rigid tube. Nevertheless, after the parts have been joined together, such a reliable press fit of the parts into one another is obtained that there can be no relative displacement between them during assembly and the intended use.

Nach einer vorteilhaften Ausgestaltung ist es vorgesehen, daß die Rippen gleichmäßig in Umfangsrichtung verteilt sind. Die sich beim Zusammenfügen der beiden Teile ergebenden Verformungskräfte sind dementsprechend ebenfalls gleichmäßig in Umfangsrichtung verteilt. Die Durchführung des Fügeprozesses wird dadurch wesentlich vereinfacht. Anschließend läßt sich die Ventilschaftdichtung als in sich geschlossene Baueinheit verwenden und montieren.According to an advantageous embodiment, it is provided that the ribs are evenly distributed in the circumferential direction. The deformation forces resulting when the two parts are joined together are accordingly also uniformly distributed in the circumferential direction. The implementation of the joining process is significantly simplified. The valve stem seal can then be used and installed as a self-contained unit.

Die Rippen haben zweckmäßig ein dreieckiges Profil, das so angeordnet ist, daß die Basis den Zylinderabschnitt bzw. Dichtring, auf dem die jeweilige Rippe angeordnet ist, verstärkt und die Spitze die Gegenfläche nach dem Zusammenfügen anliegend berührt.The ribs expediently have a triangular profile, which is arranged in such a way that the base reinforces the cylinder section or sealing ring on which the respective rib is arranged, and the tip touches the mating surface after assembly.

Als zweckmäßig hat es sich erwiesen, wenn die Höhe der Rippen, gemessen in radialer Richtung, einige Hundertstel Millimeter mehr als die Differenz zwischen dem halben Innendurchmesser des Zylinderabschnitts und dem halben Außendurchmesser des Dichtrings beträgt.It has proven expedient if the height of the ribs, measured in the radial direction, is a few hundredths of a millimeter more than the difference between half the inner diameter of the cylinder section and half the outer diameter of the sealing ring.

Ein Vorteil der erfindungsgemäßen Ventilschaftdichtung besteht darin, daß sowohl der Zylinderabschnitt als auch der Versteifungsring große Herstellungenauigkeiten haben können, ohne daß sich nach dem Ineinandereinfügen beider Teile eine nennenswerte Beeinträchtigung der resultierenden Haftverbindung ergibt.An advantage of the valve stem seal according to the invention is that both the cylinder section and the stiffening ring can have large manufacturing inaccuracies without the resultant impairment of the resulting adhesive connection after the two parts have been inserted into one another.

Der Zylinderabschnitt kann an dem von dem ersten Flansch abgewandten Ende durch einen zweiten, radial nach innen vorstehenden Flansch begrenzt sein. Die Sicherheit gegen eine Auflösung der Verbindung zwischen beiden Teilen wird dadurch weiter vergrößert.The cylinder section can be delimited at the end facing away from the first flange by a second, radially inwardly projecting flange. This further increases the security against a breakup of the connection between the two parts.

Nach einer vorteilhaften Ausgestaltung ist es vorgesehen, daß der Zylinderabschnitt und der zweite Flansch den Dichtring und die Dichtlippe auf ihrer gesamten axialen Länge übergreifen und daß die Dichtlippe in radialer Richtung frei beweglich ist. Die Dichtlippe ist durch den sie umschließenden Zylinderabschnitt bzw. zweiten Flansch in ausgezeichneter Weise vor Beschädigungen geschützt, was während der Herstellung, der Lagerung, des Transports und der Montage der Ventilschaftdichtung von großem Vorteil ist.According to an advantageous embodiment, it is provided that the cylinder section and the second flange overlap the sealing ring and the sealing lip over their entire axial length and that the sealing lip is freely movable in the radial direction. The sealing lip is excellently protected from damage by the cylinder section or second flange surrounding it, which is of great advantage during manufacture, storage, transport and assembly of the valve stem seal.

Während der bestimmungsgemäßen Verwendung in einer Verbrennungskraftmaschine gelangt die Ventilschaftdichtung bevorzugt in einer senkrechten Lage zur Anwendung, wobei das im Bereich der Ventilsteuerung vorhandene Sprühöl in den Zwischenraum zwischen dem Zylinderabschnitt, der Dichtlippe und dem Ventilschaft gelangt und sich aufstaut. Das aufgestaute Öl kann hier auch bei einer Stillsetzung der Verbrennungskraftmaschine eine längere Zeit verweilen, wodurch es bei einer erneuten Inbetriebnahme sofort schmierend zur Verfügung steht. Der Verschleiß der erfindungsgemäßen Ventilschaftdichtung ist dadurch reduziert und deren Gebrauchsdauer deutlich verbessert.During the intended use in an internal combustion engine, the valve stem seal is preferably used in a vertical position, the spray oil present in the area of the valve control reaching the space between the cylinder section, the sealing lip and the valve stem and building up. The pent-up oil can linger here for a long time even when the internal combustion engine is stopped, which means that it is immediately available for lubrication when it is restarted. The wear of the valve stem seal according to the invention is thereby reduced and its service life is significantly improved.

Der Dichtring besteht zweckmäßig aus einem Versteifungsring, beispielsweise aus Metall oder Kunststoff, sowie einem elastischen Dichtelement. Letzteres kann einstückig ineinander übergehend zumindest eine mit dem Ventilschaft in Eingriff bringbare Dichtlippe umfassen und zumindest eine mit der Ventilführung in Eingriff bringbare Dichtrippe. Letztere ist zweckmäßig so an den Versteifungsring angeformt, daß sich nach dem Aufschieben der Ventilschaftdichtung auf den Außenumfang einer Ventilführung eine radiale Verpressung der Dichtrippe zwischen der Ventilführung und dem Versteifungsring ergibt.The sealing ring expediently consists of a stiffening ring, for example made of metal or plastic, and an elastic sealing element. The latter can, in one piece, merge into one another at least one sealing lip which can be brought into engagement with the valve stem and at least one sealing rib which can be brought into engagement with the valve guide. The latter is expediently molded onto the stiffening ring in such a way that after the valve stem seal has been pushed onto the outer circumference of a valve guide, there is a radial compression of the sealing rib between the valve guide and the stiffening ring.

Der Gegenstand der Erfindung wird nachfolgend anhand der Zeichnung weiter verdeutlicht. Es zeigen:

Fig. 1
eine beispielhafte Ausführung der erfindungsgemäßen Ventilschaftdichtung in halbgeschnittener Darstellung.
Fig. 2
die Ventilschaftdichtung gemäß Fig. 1 in quergeschnittener Darstellung.
The object of the invention is illustrated below with reference to the drawing. Show it:
Fig. 1
an exemplary embodiment of the valve stem seal according to the invention in half-section.
Fig. 2
the valve stem seal of FIG. 1 in a cross-sectional view.

Die in Fig. 1 in halbgeschnittener Darstellung wiedergegebene Ventilschaftdichtung umfaßt ein verformungssteifes Rohr 6, das an dem einen Ende durch einen ersten Zylinderabschnitt 3 und an dem anderen Ende durch einen radial nach außen vorstehenden Flansch 2 begrenzt ist, wobei in dem Zylinderabschnitt 3 ein Dichtring 7 unverrückbar eingefügt ist, der eine in axialer Richtung vorstehende, radialelastische Dichtlippe 9 aufweist, die mit einem in der Zeichnung nicht dargestellten Ventilschaft in Eingriff bringbar ist. Auf dem Innenumfang des Zylinderabschnitts 3 sind fünf gleichmäßig in Umfangsrichtung verteilte Rippen 13 vorgesehen, die ein dreieckiges Profil haben (Fig. 2) und radial in Richtung des Dichtringes vorstehen. Die Rippen 13 erstrecken sich parallel zu der Achse 1a der Ventilschaftdichtung. Die sie in Umfangsrichtung begrenzenden Flächen durchschneiden einander in radial nach innen weisenden Kanten unter einem Winkel von 72°. Der Winkel kann in Abhängigkeit von den im Einzelfall gegebenen Erfordernissen gegebenenfalls größer oder kleiner gewählt werden. Der Dichtring ist in dem von den Rippen 13 berührten Bereich von einem metallischen Versteifungsring 11 umschlossen. Der Versteifungsring 11 hat in dem mit den Rippen in Eingriff gelangenden Bereich den halben Außendurchmesser r (Fig. 2). Dieser ist bei üblichen Baugrößen von KFZ-Motoren um einige Hundertstel Millimeter größer als der Radius einer gedachten Zylinderfläche, auf dem die radial nach innen weisenden Spitzen der Rippen 13 im neuwertigen und unverformten Zustand angeordnet sind. Zweckmäßigerweise beträgt der diesbezügliche Unterschied etwa 100 µm. Zum Einfügen des Dichtringes 7 in das verformungssteife Rohr sind aus diesem Grunde nur relativ geringe Kräfte nötig. Dennoch wird nach dem Zusammenfügen beider Teile ein so fester Preßsitz erzielt, daß sich während der Lagerung und der bestimmungsgemäßen Verwendung keine Relativverlagerung zwischen beiden Teilen mehr ergeben kann.The valve stem seal shown in FIG. 1 in a half-section comprises a deformation-resistant tube 6 which is delimited at one end by a first cylinder section 3 and at the other end by a flange 2 projecting radially outwards, a sealing ring 7 being provided in the cylinder section 3 is inserted immovably, one in the axial direction projecting, radially elastic sealing lip 9, which can be brought into engagement with a valve stem, not shown in the drawing. On the inner circumference of the cylinder section 3, five ribs 13 are provided which are uniformly distributed in the circumferential direction and have a triangular profile (FIG. 2) and protrude radially in the direction of the sealing ring. The ribs 13 extend parallel to the axis 1a of the valve stem seal. The surfaces delimiting them in the circumferential direction intersect one another in radially inward-pointing edges at an angle of 72 °. Depending on the requirements in the individual case, the angle can optionally be chosen to be larger or smaller. The sealing ring is enclosed in the area touched by the ribs 13 by a metallic stiffening ring 11. The stiffening ring 11 has half the outer diameter r in the region engaging the ribs (FIG. 2). In the usual sizes of motor vehicle engines, this is a few hundredths of a millimeter larger than the radius of an imaginary cylinder surface on which the radially inward-pointing tips of the ribs 13 are arranged in new and undeformed condition. The difference in this regard is expediently about 100 μm. For this reason, only relatively small forces are required to insert the sealing ring 7 into the rigid tube. Nevertheless, after the two parts have been joined together, such a tight press fit is achieved that there can no longer be a relative displacement between the two parts during storage and the intended use.

Die Dichtlippe 8 wird bei dem gezeigten Ausführungsbeispiel umschlossen von dem Zylinderabschnitt 3 und dem zweiten Flansch 4 des verformungssteifen Rohres 6. Sie wird dadurch in ausgezeichneter Weise vor Beschädigungen geschützt, was während der Herstellung, der Lagerung und der Montage von erheblichem Vorteil ist. Dennoch ist die Dichtlippe 8 auch während der bestimmungsgemäßen Verwendung in radialer Richtung ausgezeichnet beweglich, was für die Erzielung eines guten Abdichtungsergebnisses von großem Vorteil ist. Die Dichtlippe 8 ist außenseitig mit einer umlaufenden Nut versehen, in die eine Andrückfeder 9 eingebettet ist.In the exemplary embodiment shown, the sealing lip 8 is enclosed by the cylinder section 3 and the second flange 4 of the deformation-resistant tube 6. It is thereby protected from damage in an excellent manner, which is of considerable advantage during manufacture, storage and assembly. Nevertheless, the sealing lip 8 is also extremely mobile in the radial direction during the intended use, which is of great advantage for achieving a good sealing result. The sealing lip 8 is provided on the outside with a circumferential groove in which a pressure spring 9 is embedded.

Das verformungssteife Rohr 1 weist zwischen dem Zylinderabschnitt 3 und dem ersten Flansch 2 in einem Teilbereich einen kegelig in Richtung des ersten Flansches 2 einen erweiterten Innendurchmesser auf. Das Einfügen des Dichtringes 7 aus der Richtung des ersten Flansches 2 ist dadurch stark erleichtert. Das die Dichtlippe 8 umfassende Dichtelement 10 des Dichtringes 7 besteht bei dem gezeigten Ausführungsbeispiel aus Gummi. Andere einschlägig verwendete Werkstoffe können in bezug auf seine Erzeugung ebenfalls zur Anwendung gelangen.The deformation-resistant tube 1 has between the cylinder section 3 and the first flange 2 in a partial area a conical in the direction of the first flange 2 an enlarged inner diameter. The insertion of the sealing ring 7 from the direction of the first flange 2 is greatly facilitated. The sealing element 10, comprising the sealing lip 8, of the sealing ring 7 is made of rubber in the exemplary embodiment shown. Other materials used in this field can also be used in relation to its production.

Der Versteifungsring des Dichtringes 7 weist in dem dem Zylinderabschnitt 3 gegenüberliegenden Bereich einen größeren Außendurchmesser 13 auf, als in dem in Richtung des ersten Flansches 2 anschließenden Teilbereich 11. Die für das Einfügen des Dichtringes 7 in das verformungssteife Rohr 6 erforderlichen Einpreßkräfte sind dadurch auf das absolut notwendige Maß reduziert. Während des Einfügens ergibt sich eine plastische Deformierung der in radialer Richtung nach innen weisenden Kanten der Rippen 13. Diese tritt nur so weitgehend in Erscheinung, wie der Versteifungsring 11 tatsächlich in das verformungssteife Rohr 6 eingepreßt wird. Bei dem gezeigten Ausführungsbeispiel wurde der Einpreßvorgang abgebrochen, bevor die Rippen in axialer Richtung völlig deformiert sind. Hierdurch ist eine Stufe 15 erhalten geblieben, die verhindert, daß der Dichtring 7 während der Montage oder Verwendung der Ventilschaftdichtung noch weiter in Richtung des zweiten Flansches 4 verlagert wird und an eine Stelle gelangt, an der seine Funktion beeinträchtigt ist.The stiffening ring of the sealing ring 7 has a larger outside diameter 13 in the area opposite the cylinder section 3 than in the partial area 11 adjoining in the direction of the first flange 2. The press-in forces required for inserting the sealing ring 7 into the deformation-resistant tube 6 are therefore due to that absolutely necessary measure reduced. During the insertion there is a plastic deformation of the edges of the ribs 13 pointing inwards in the radial direction. This occurs only to the extent that the stiffening ring 11 is actually pressed into the deformation-resistant tube 6. In the embodiment shown, the press-in process was stopped before the ribs were completely deformed in the axial direction. As a result, a step 15 has been preserved, which prevents the sealing ring 7 from being displaced further towards the second flange 4 during assembly or use of the valve stem seal and from reaching a point at which its function is impaired.

Zwischen dem hohlkegeligen Teilbereich 5 des verformungssteifen Rohres und dem ersten Flansch 2 ist ein weiterer zylindrischer Teilbereich des verformungssteifen Rohres 1 vorhanden. Dieser verleiht einer in der Zeichnung nicht wiedergegebenen Ventilfeder die in bezug auf die Gewährleistung einer guten Funktion wünschenswerte Führung. Der erste Flansch 2 dient im übrigen zur Abstützung der Ventilfeder auf einem nicht gezeigten Zylinderkopf einer Verbrennungskraftmaschine und schützt diesen vor einer Beschädigung durch die Ventilfeder. Er besteht einschließlich des Rohres 1 bevorzugt aus einem tiefgezogenen Stahlblech.A further cylindrical portion of the rigid tube 1 is present between the hollow-conical portion 5 of the rigid tube and the first flange 2. This gives a valve spring which is not shown in the drawing the guidance which is desirable with regard to ensuring a good function. The first flange 2 also serves to support the valve spring on a cylinder head, not shown, of an internal combustion engine and protects it from damage by the Valve spring. It preferably includes the tube 1 from a deep-drawn sheet steel.

Claims (8)

  1. A valve stem seal comprising a tube (1) resistant to deformation which is bounded at one end by a first cylindrical section (3) and at the other end by a flange (2) which projects radially outwards, the cylindrical section (3) having inserted into it in a self-locking manner a sealing ring (7) which has a radially flexible sealing lip (9) which projects in the axial direction and can be brought into engagement with the valve stem, characterized in that circumferentially distributed ribs (13) which project radially in the direction of the sealing ring (7) are provided on the cylindrical section (3) and/or circumferentially distributed ribs (13) which project radially in the direction of the cylindrical section (9) are provided on the sealing ring (7), and in that the sealing ring (7) and the cylindrical section (3) touch one another only in the region of the ribs (13).
  2. A valve stem seal according to claim 1, characterized in that the ribs (13) are distributed uniformly in the circumferential direction.
  3. A valve stem seal according to either of claims 1 and 2, characterized in that the ribs (13) have a triangular profile which tapers from the base in the direction of the tip.
  4. A valve stem seal according to any of claims 1 to 3, characterized in that the height of the ribs (13), measured in the radial direction, amounts to a few hundreds of a millimetre more than the difference between half the inside diameter of the cylindrical section and half the outside diameter of the sealing ring.
  5. A valve stem seal according to any of claims 1 to 4, characterized in that the cylindrical section (3) is bounded at the end remote from the first flange (2) by a second flange (4) projecting radially inwards.
  6. A valve stem seal according to claim 5, characterized in that the cylindrical section (3) and the second flange (4) overlap the sealing ring (7) and the sealing lip (8) axially over their entire length and in that the sealing lip (8) is freely movable in the radial direction.
  7. A valve stem seal according to any of claims 1 to 6, characterized in that the sealing ring (7) comprises a reinforcing ring (11) and a flexible sealing element.
  8. A valve stem seal according to claim 7, characterized in that the sealing element comprises at least one sealing lip (8) which can be brought into engagement with the valve stem and at least one sealing rib which can be brought into engagement with the valve guide, the said lip and rib merging integrally into one another.
EP19940107573 1993-07-20 1994-05-17 Valve stem seal Expired - Lifetime EP0639695B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9308898A FR2708037B1 (en) 1993-07-20 1993-07-20 Valve stem seal.
FR9308898 1993-07-20

Publications (2)

Publication Number Publication Date
EP0639695A1 EP0639695A1 (en) 1995-02-22
EP0639695B1 true EP0639695B1 (en) 1996-07-24

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19940107573 Expired - Lifetime EP0639695B1 (en) 1993-07-20 1994-05-17 Valve stem seal

Country Status (4)

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EP (1) EP0639695B1 (en)
DE (1) DE59400451D1 (en)
ES (1) ES2091067T3 (en)
FR (1) FR2708037B1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1276427B1 (en) * 1995-06-21 1997-10-31 Corcos Ind Spa SEAL FOR A VALVE OF AN INTERNAL COMBUSTION ENGINE.
DE19945348C2 (en) * 1999-09-22 2003-07-10 Freudenberg Carl Kg Seal for reciprocating machine parts

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3902518A1 (en) * 1989-01-28 1990-08-02 Goetze Ag VALVE SEAL
US5174256A (en) * 1991-11-25 1992-12-29 Dana Corporation Variable guide height valve seal

Also Published As

Publication number Publication date
FR2708037B1 (en) 1995-09-01
DE59400451D1 (en) 1996-08-29
FR2708037A1 (en) 1995-01-27
ES2091067T3 (en) 1996-10-16
EP0639695A1 (en) 1995-02-22

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