EP1752622B1 - Desmodromic valve drive - Google Patents

Desmodromic valve drive Download PDF

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Publication number
EP1752622B1
EP1752622B1 EP20060009750 EP06009750A EP1752622B1 EP 1752622 B1 EP1752622 B1 EP 1752622B1 EP 20060009750 EP20060009750 EP 20060009750 EP 06009750 A EP06009750 A EP 06009750A EP 1752622 B1 EP1752622 B1 EP 1752622B1
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EP
European Patent Office
Prior art keywords
cam
valve
base circle
drive
case
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Expired - Fee Related
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EP20060009750
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German (de)
French (fr)
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EP1752622A1 (en
Inventor
Dietmar Schwarzenthal
Joachim Grünberger
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Dr Ing HCF Porsche AG
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Dr Ing HCF Porsche AG
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Publication of EP1752622A1 publication Critical patent/EP1752622A1/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
    • F01L1/30—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of positively opened and closed valves, i.e. desmodromic valves

Definitions

  • the invention relates to a positively controlled valve drive for controlling the opening and closing movement of at least one valve device, according to the preamble of patent claim 1.
  • a positively controlled valve train of the type mentioned above which serve to control the opening and closing movement of a valve device.
  • the valve drive has a cam element with a first cam contour with a first base circle and a second cam contour with a second base circle, wherein the second base circle is arranged coaxially to the first base circle and has a smaller diameter than the first base circle.
  • the first cam contour is surrounded by a rigid enclosing element formed integrally with the cam element, so that a cam groove is formed between the enclosing element and the second base circle, into which a drive element coupled to the valve device, in this case a mounted roller, engages.
  • a spring means disposed between the valve means and the cam member.
  • a valve drive for internal combustion engines which has at least one driven cam element and a cam follower element which can be moved by the cam element against a restoring force.
  • the cam member is rotatably disposed in a flexible enclosing member which is hingedly connected to the cam follower.
  • a positive control for a valve of an internal combustion engine which comprises a rotating cam and means for establishing a positive connection between the cam and valve stem.
  • the cam is frictionally enclosed by a band, which is articulated in a plane perpendicular to the axis of rotation of the cam deformable at the free end portion of the valve stem.
  • the object of the invention is to provide a positively controlled valve train according to the preamble of claim 1, which is simple in construction and inexpensive to produce.
  • the object is with a positively controlled valve drive for controlling the opening and closing movement of at least one valve device, with at least one driven cam element having a first cam contour with a first base circle , which is wrapped by a Umsch adoptedungselement, achieved in that the cam member has a second cam contour with a second base circle having a smaller diameter than the first base circle and is arranged coaxially with the first base circle, that between the enclosing element and the second cam contour results in a cam groove, in which engages a drive element which is coupled to the valve device, and that it is a flexible band in the enclosing element.
  • the first cam contour is also referred to as the outer cam contour and the second cam contour as the inner cam contour.
  • the cam element with the two cam contours can be produced in a single-pass manufacturing process, for example by means of a profile tool, or in a primary molding process, for example by casting or sintering.
  • the drive element slides or rolls on a groove flank of the cam groove.
  • the valve device To open the valve device is accelerated by the second or inner cam contour.
  • the first or outer cam contour which is transmitted by means of the enclosing element on the drive element, the valve device is braked again.
  • the separate enclosure member is formed by a flexible band attached to the first cam contour.
  • the enclosing element is frictionally and / or positively secured to the first cam contour. That is, the enclosing member rotates with the cam member during operation.
  • the enclosing element is not articulated to the valve device.
  • a further preferred embodiment of the valve train is characterized in that the drive element has the shape of a circular cylinder whose outer diameter corresponds to the distance between the two basic circles. As a result, a play-free engagement of the drive element is ensured in the cam groove.
  • the drive element can also be referred to as a driver element.
  • a further preferred embodiment of the valve train is characterized in that the drive element is coupled via a lever device with at least one coupling element which is coupled via the lever device with a valve stem of the valve device.
  • the lever device guides both the movement of the drive element and the movement of the coupling element.
  • a further preferred embodiment of the valve drive is characterized in that the coupling element is arranged between two coils which are attached to the valve stem. Thereby, the coupling element is coupled in a simple manner with the valve stem.
  • a further preferred embodiment of the valve drive is characterized in that the lever device is pivotally mounted on an end remote from the coupling element.
  • the pivot axis of the lever means is arranged parallel to the axis of a camshaft which drives the cam member.
  • a further preferred embodiment of the valve train is characterized in that the cam element on both sides in each case a first cam contour with a first base circle, wherein the two first cam contours are looped by the enclosing element, and each having a second cam contour with a second base circle having a smaller Diameter as the first Base circle and is arranged coaxially to the first base circle, that in each case a cam groove results between the enclosing element and the two second cam contours, in each of which engages a drive element which is coupled to a valve device.
  • a further preferred exemplary embodiment of the valve drive is characterized in that the drive elements are connected via the lever device to at least one coupling element, which is in each case coupled to a valve stem of one of the valve devices.
  • the pivot axis of the lever device is arranged parallel to the common axis of the drive elements.
  • FIGS. 1 to 4 is a positively controlled valve train 1 of an internal combustion engine, in particular a motor vehicle engine, shown in different views.
  • the positively controlled valve train 1 serves to control the opening and closing movement of two valves 4, 5.
  • the two valves 4, 5 each have a valve disk 6, 7, which serves to close a (not shown) opening in a working space of an internal combustion engine and specifically release.
  • the closing movement direction of the valve disks 6, 7 is indicated by an arrow 9.
  • the opening movement direction of the valve disks 6, 7 is indicated by an arrow 10.
  • the valve disks 6, 7 are each integrally connected to a valve stem 12, 13.
  • the valve stems 12, 13 are each guided back and forth in the longitudinal direction.
  • the collars 15, 16 each have a contact surface on their mutually facing end faces. The two contact surfaces are spaced apart. Between the two contact surfaces of the collars 15, 16 two coupling elements 18, 19 are arranged, which surround the valve stem 13 like a fork. The coupling elements 18, 19 are integrally connected to a lever device 20.
  • the lever device 20 has two lever arms 21, 22, which originate from a base body 23 of the lever device 20.
  • the coupling elements 18, 19 formed.
  • the coupling elements 18, 19 each have the shape of a circular disk provided with a through hole, which is cut off at the end facing away from the lever arm 21.
  • two bearing journals 24, 25 extend from the base body 23 of the lever device 20, which serve to pivotally mount the lever device 20 about a pivot axis 26.
  • the coupling element 19 has a projection 29, from which approximately at the level of the collar 16 on the collar 16 side facing away from a drive element 30, which is also referred to as a driver element and has the shape of a circular cylindrical pin.
  • the drive element 30 is arranged a cam groove 32.
  • the cam groove 32 has a groove bottom 33, which from an end face 34 of a Cam member 35 is formed.
  • the cam element 35 comprises a first cam 36, on whose circumference a first or outer cam contour 41 is formed with a first base circle.
  • a second or inner cam contour 42 having a second base circle coaxially or concentric with the first base circle of the first cam contour 41 and having a smaller diameter than the first base circle is formed on a second cam 44 which is integral with and elevated to the second cam 44 first cam 36 of the cam member 35 is formed.
  • cam stub 46 goes out from second cam 44.
  • cam stub 47 goes out, which is arranged coaxially with the camshaft stub 46.
  • the two cam stub 46, 47 may be part of a camshaft through which the positively controlled valve train 1 is driven.
  • the axis of rotation of the camshaft stubs 46, 47 is in FIG. 3 designated 45.
  • the first outer cam contour 41 of the cam element 35 is looped around by an enclosing element 48, which is also referred to as a looping element.
  • the enclosing member 48 is a flexible band wrapped around the first cam 36, also referred to as an outer cam or outer cam, and secured thereto by frictional engagement or positive engagement on this cam.
  • the enclosing element projects beyond the outer cam 36 in the axial direction.
  • the enclosing member 48 projects beyond the outer cam 36 as far as the second inner cam 44 extends in that direction.
  • the projection of the enclosing element 48 thus corresponds to the thickness of the inner cam 44 in the axial direction.
  • the second cam contour 42 of the inner cam 44 forms a groove flank of the cam groove 32. The other groove flank is formed by the protruding portion of the enclosing element 48.
  • the encircling element 48 is not formed by an endless belt, but has two ends that pass through a closing element 55 attached to each other.
  • two collars 65, 66 are provided in the region of the free end of the valve stem 12 in the same way as on the valve stem 13.
  • the coupling element 69 has a projection 79 from which, in the same way as in the projection 29, a drive element extends, which engages in a cam groove which is provided analogously to the cam groove 32 on the opposite end face of the cam member 35.
  • valve drive according to the invention By means of the valve drive according to the invention, it is possible to achieve performance increases with respect to the valve time cross section and / or a higher end speed.
  • a significant advantage of the valve drive according to the invention is that the friction of the valve train can be reduced. As a result, fuel consumption can be reduced, in particular at low engine speeds.
  • the two cam contours of the cam element 35 are produced, for example, with a profile tool or in another shaping method, such as casting or sintering, in one operation.
  • the base circle difference of the two cam contours 41, 42 corresponds exactly to the outer diameter of the drive element 30, which can be formed by a roller.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)

Description

Die Erfindung betrifft einen zwangsgesteuerten Ventiltrieb zum Steuern der Öffnungs- und Schließbewegung mindestens einer Ventileinrichtung, gemäß Oberbegriff des Patentanspruchs 1.The invention relates to a positively controlled valve drive for controlling the opening and closing movement of at least one valve device, according to the preamble of patent claim 1.

Beispielsweise aus der US 1 280 912 A oder GB 19 193 A ist ein zwangsgesteuerter Ventiltrieb eingangs genannter Art bekannt, der der Steuerung der Öffnungs- und Schließbewegung einer Ventileinrichtung dienen. Der Ventiltrieb weist ein Nockenelement mit einer ersten Nockenkontur mit einem ersten Grundkreis und eine zweite Nockenkontur mit einem zweiten Grundkreis auf, wobei der zweite Grundkreis koaxial zum ersten Grundkreis angeordnet ist und einen kleineren Durchmesser als der erste Grundkreis aufweist. Die erste Nockenkontur ist von einem einteilig mit dem Nockenelement ausgebildeten starren Umschließungselement umgeben, so dass zwischen Umschließungselement und dem zweiten Grundkreis eine Nockennut gebildet ist, in die ein mit der Ventileinrichtung gekoppeltes Antriebselement, hier eine gelagerte Rolle, eingreift. Um das Ventilspiel ausgleichen zu können, ist gemäß GB 19 193 A eine Federeinrichtung zwischen der Ventileinrichtung und dem Nockenelement angeordnet.For example, from the US Pat. No. 1 280 912 A or GB 19 193 A is a positively controlled valve train of the type mentioned above, which serve to control the opening and closing movement of a valve device. The valve drive has a cam element with a first cam contour with a first base circle and a second cam contour with a second base circle, wherein the second base circle is arranged coaxially to the first base circle and has a smaller diameter than the first base circle. The first cam contour is surrounded by a rigid enclosing element formed integrally with the cam element, so that a cam groove is formed between the enclosing element and the second base circle, into which a drive element coupled to the valve device, in this case a mounted roller, engages. To be able to compensate for the valve clearance is according to GB 19 193 A a spring means disposed between the valve means and the cam member.

Zwangsgesteuerte Ventiltriebe oder Ventilsteuerungen werden auch als desmodromische Ventilsteuerungen bezeichnet. Aus der EP 1 247 946 A2 ist ein Ventiltrieb für Brennkraftmaschinen bekannt, der mindestens ein angetriebenes Nockenelement und ein vom Nockenelement gegen eine Rückstellkraft bewegbares Nockenfolgeelement aufweist. Das Nockenelement ist drehbar in einem flexiblen Umschließungselement angeordnet, das mit dem Nockenfolgeelement gelenkig verbunden ist. Aus der DE 37 00 715 A1 ist eine Zwangssteuerung für ein Ventil einer Brennkraftmaschine bekannt, das einen rotierenden Nocken und Mittel zur Herstellung einer formschlüssigen Verbindung zwischen Nocken und Ventilschaft umfasst. Der Nocken ist von einem Band reibungsarm eng umschlossen, das in einer zur Rotationsachse des Nockens senkrechten Ebene verformbar am freien Endbereich des Ventilschafts angelenkt ist. Diese bekannten zwangsgesteuerten Ventiltriebe sind aufgrund der großen Anzahl der verwendeten Bauteile oder aufgrund von hohen Toleranzanforderungen sehr komplex.Forced-control valve trains or valve controls are also referred to as desmodromic valve controls. From the EP 1 247 946 A2 For example, a valve drive for internal combustion engines is known which has at least one driven cam element and a cam follower element which can be moved by the cam element against a restoring force. The cam member is rotatably disposed in a flexible enclosing member which is hingedly connected to the cam follower. From the DE 37 00 715 A1 a positive control for a valve of an internal combustion engine is known which comprises a rotating cam and means for establishing a positive connection between the cam and valve stem. The cam is frictionally enclosed by a band, which is articulated in a plane perpendicular to the axis of rotation of the cam deformable at the free end portion of the valve stem. These known positively controlled valve trains are very complex due to the large number of components used or due to high tolerance requirements.

Aufgabe der Erfindung ist es, einen zwangsgesteuerten Ventiltrieb gemäß dem Oberbegriff des Anspruchs 1 zu schaffen, der einfach aufgebaut und kostengünstig herstellbar ist.The object of the invention is to provide a positively controlled valve train according to the preamble of claim 1, which is simple in construction and inexpensive to produce.

Die Aufgabe ist bei einem zwangsgesteuerten Ventiltrieb zum Steuern der Öffnungs- und Schließbewegung mindestens einer Ventileinrichtung, mit mindestens einem angetriebenen Nockenelement, das eine erste Nockenkontur mit einem ersten Grundkreis aufweist, die von einem Umschließungselement umschlungen ist, dadurch gelöst, dass das Nockenelement eine zweite Nockenkontur mit einem zweiten Grundkreis aufweist, der einen kleineren Durchmesser als der erste Grundkreis aufweist und koaxial so zu dem ersten Grundkreis angeordnet ist, dass sich zwischen dem Umschließungselement und der zweiten Nockenkontur eine Nockennut ergibt, in die ein Antriebselement eingreift, das mit der Ventileinrichtung gekoppelt ist, und dass es sich bei dem Umschließungselement um ein flexibles Band handelt. Die erste Nockenkontur wird auch als äußere und die zweite Nockenkontur als innere Nockenkontur bezeichnet. Das Nockenelement mit den beiden Nockenkonturen kann in einem trennenden Fertigungsverfahren, zum Beispiel mit Hilfe eines Profilwerkzeugs, oder in einem Urformverfahren, zum Beispiel durch Gießen oder Sintern, in einem Arbeitsgang erzeugt werden. Das Antriebselement gleitet oder wälzt sich an einer Nutflanke der Nockennut. Aus der US 1 238 175 A ist zwar ein zwangsgesteuerter Ventiltrieb bekannt, der ein Nockenelement mit einer Nockennut aufweist, allerdings ist das bekannte Nockenelement inklusive der Nockennut mit zwei Nutflanken aus einem Stück hergestellt. Durch dieses US-Patent wird weder offenbart noch nahe gelegt, eine der Nutflanken der Nockennut mit Hilfe eines separaten Umschließungselements zu realisieren. Der erfindungsgemäße Ventiltrieb liefert unter anderem den Vorteil, dass die Nockennut fertigungstechnisch relativ einfach herstellbar ist. Zum Öffnen wird die Ventileinrichtung durch die zweite oder innere Nockenkontur beschleunigt. Durch die erste oder äußere Nockenkontur, die mit Hilfe des Umschließungselements auf das Antriebselement übertragen wird, wird die Ventileinrichtung wieder gebremst. Das separate Umschließungselement ist von einem flexiblen Band gebildet, das an der ersten Nockenkontur befestigt ist. Vorzugsweise ist das Umschließungselement reib- und/oder formschlüssig an der ersten Nockenkontur befestigt. Das heißt, das Umschließungselement dreht sich im Betrieb mit dem Nockenelement. Im Unterschied zu den bekannten zwangsgesteuerten Ventiltrieben ist das Umschließungselement nicht an die Ventileinrichtung angelenkt.The object is with a positively controlled valve drive for controlling the opening and closing movement of at least one valve device, with at least one driven cam element having a first cam contour with a first base circle , which is wrapped by a Umschließungselement, achieved in that the cam member has a second cam contour with a second base circle having a smaller diameter than the first base circle and is arranged coaxially with the first base circle, that between the enclosing element and the second cam contour results in a cam groove, in which engages a drive element which is coupled to the valve device, and that it is a flexible band in the enclosing element. The first cam contour is also referred to as the outer cam contour and the second cam contour as the inner cam contour. The cam element with the two cam contours can be produced in a single-pass manufacturing process, for example by means of a profile tool, or in a primary molding process, for example by casting or sintering. The drive element slides or rolls on a groove flank of the cam groove. From the US Pat. No. 1,238,175 A Although a positively controlled valve train is known which has a cam element with a cam groove, however, the known cam element including the cam groove is produced with two groove flanks in one piece. By this US patent is neither disclosed nor suggested to realize one of the groove flanks of the cam groove by means of a separate enclosing element. The valve train according to the invention provides, inter alia, the advantage that the cam groove can be produced relatively easily in terms of production engineering. To open the valve device is accelerated by the second or inner cam contour. By the first or outer cam contour, which is transmitted by means of the enclosing element on the drive element, the valve device is braked again. The separate enclosure member is formed by a flexible band attached to the first cam contour. Preferably, the enclosing element is frictionally and / or positively secured to the first cam contour. That is, the enclosing member rotates with the cam member during operation. In contrast to the known positively controlled valve trains, the enclosing element is not articulated to the valve device.

Ein weiteres bevorzugtes Ausführungsbeispiel des Ventiltriebs ist dadurch gekennzeichnet, dass das Antriebselement die Gestalt eines Kreiszylinders aufweist, dessen Außendurchmesser dem Abstand zwischen den beiden Grundkreisen entspricht. Dadurch wird ein spielfreier Eingriff des Antriebselements in die Nockennut gewährleistet. Das Antriebselement kann auch als Mitnehmerelement bezeichnet werden.A further preferred embodiment of the valve train is characterized in that the drive element has the shape of a circular cylinder whose outer diameter corresponds to the distance between the two basic circles. As a result, a play-free engagement of the drive element is ensured in the cam groove. The drive element can also be referred to as a driver element.

Ein weiteres bevorzugtes Ausführungsbeispiel des Ventiltriebs ist dadurch gekennzeichnet, dass das Antriebselement über eine Hebeleinrichtung mit mindestens einem Kopplungselement gekoppelt ist, das über die Hebeleinrichtung mit einem Ventilschaft der Ventileinrichtung gekoppelt ist. Durch die Hebeleinrichtung werden sowohl die Bewegung des Antriebselements als auch die Bewegung des Kopplungselements geführt.A further preferred embodiment of the valve train is characterized in that the drive element is coupled via a lever device with at least one coupling element which is coupled via the lever device with a valve stem of the valve device. The lever device guides both the movement of the drive element and the movement of the coupling element.

Ein weiteres bevorzugtes Ausführungsbeispiel des Ventiltriebs ist dadurch gekennzeichnet, dass das Kopplungselement zwischen zwei Bunden angeordnet ist, die an dem Ventilschaft angebracht sind. Dadurch wird das Kopplungselement auf einfache Art und Weise mit dem Ventilschaft gekoppelt.A further preferred embodiment of the valve drive is characterized in that the coupling element is arranged between two coils which are attached to the valve stem. Thereby, the coupling element is coupled in a simple manner with the valve stem.

Ein weiteres bevorzugtes Ausführungsbeispiel des Ventiltriebs ist dadurch gekennzeichnet, dass die Hebeleinrichtung an einem dem Kopplungselement abgewandten Ende schwenkbar gelagert ist. Vorzugsweise ist die Schwenkachse der Hebeleinrichtung parallel zu der Achse einer Nockenwelle angeordnet, die das Nockenelement antreibt.A further preferred embodiment of the valve drive is characterized in that the lever device is pivotally mounted on an end remote from the coupling element. Preferably, the pivot axis of the lever means is arranged parallel to the axis of a camshaft which drives the cam member.

Ein weiteres bevorzugtes Ausführungsbeispiel des Ventiltriebs ist dadurch gekennzeichnet, dass das Nockenelement auf zwei Seiten jeweils eine erste Nockenkontur mit einem ersten Grundkreis, wobei die beiden ersten Nockenkonturen von dem Umschließungselement umschlungen sind, und jeweils eine zweite Nockenkontur mit einem zweiten Grundkreis aufweist, der einen kleineren Durchmesser als der erste Grundkreis aufweist und koaxial so zu dem ersten Grundkreis angeordnet ist, dass sich zwischen dem Umschließungselement und den beiden zweiten Nockenkonturen jeweils eine Nockennut ergibt, in die jeweils ein Antriebselement eingreift, das mit jeweils einer Ventileinrichtung gekoppelt ist. Dadurch wird auf einfache Art und Weise ein zwangsgesteuerter Ventiltrieb für zwei Ventileinrichtungen geschaffen.A further preferred embodiment of the valve train is characterized in that the cam element on both sides in each case a first cam contour with a first base circle, wherein the two first cam contours are looped by the enclosing element, and each having a second cam contour with a second base circle having a smaller Diameter as the first Base circle and is arranged coaxially to the first base circle, that in each case a cam groove results between the enclosing element and the two second cam contours, in each of which engages a drive element which is coupled to a valve device. As a result, a positively controlled valve drive for two valve devices is created in a simple manner.

Ein weiteres bevorzugtes Ausführungsbeispiel des Ventiltriebs ist dadurch gekennzeichnet, dass die Antriebselemente über die Hebeleinrichtung mit jeweils mindestens einem Kopplungselement verbunden sind, das jeweils mit einem Ventilschaft einer der Ventileinrichtungen gekoppelt ist. Vorzugsweise ist die Schwenkachse der Hebeleinrichtung parallel zu der gemeinsamen Achse der Antriebselemente angeordnet.A further preferred exemplary embodiment of the valve drive is characterized in that the drive elements are connected via the lever device to at least one coupling element, which is in each case coupled to a valve stem of one of the valve devices. Preferably, the pivot axis of the lever device is arranged parallel to the common axis of the drive elements.

Weitere Vorteile, Merkmale und Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung, in der unter Bezugnahme auf die Zeichnung ein Ausführungsbeispiel im Einzelnen beschrieben ist. Dabei können die in den Ansprüchen und in der Beschreibung erwähnten Merkmale jeweils einzeln für sich oder in beliebiger Kombination erfindungswesentlich sein. Es zeigen:

Figur 1
eine perspektivische Darstellung eines erfindungsgemäßen Ventiltriebs;
Figur 2
den Ventiltrieb aus Figur 1 in der Vorderansicht;
Figur 3
den Ventiltrieb aus Figur 1 in der Draufsicht und
Figur 4
den Ventiltrieb aus Figur 1 in der Seitenansicht von rechts.
Further advantages, features and details of the invention will become apparent from the following description in which, with reference to the drawings, an embodiment is described in detail. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination. Show it:
FIG. 1
a perspective view of a valve gear according to the invention;
FIG. 2
the valvetrain off FIG. 1 in front view;
FIG. 3
the valvetrain off FIG. 1 in plan view and
FIG. 4
the valvetrain off FIG. 1 in the side view from the right.

In den Figuren 1 bis 4 ist ein zwangsgesteuerter Ventiltrieb 1 einer Brennkraftmaschine, insbesondere eines Kraftfahrzeugmotors, in verschiedenen Ansichten dargestellt. Der zwangsgesteuerte Ventiltrieb 1 dient dazu, die Öffnungs- und Schließbewegung von zwei Ventilen 4, 5 zu steuern. Die beiden Ventile 4, 5 weisen jeweils einen Ventilteller 6, 7 auf, der dazu dient, eine (nicht dargestellte) Öffnung in einem Arbeitsraum einer Brennkraftmaschine zu verschließen und gezielt freizugeben. Für den Ladewechsel der Brennkraftmaschine sind die Steuerzeitquerschnitte maßgeblich, die sich aus dem Produkt von geöffneter Durchtrittsfläche und Öffnungszeit ergeben. Die Schließbewegungsrichtung der Ventilteller 6, 7 ist durch einen Pfeil 9 angegeben. Die Öffnungsbewegungsrichtung der Ventilteller 6, 7 ist durch einen Pfeil 10 angegeben. Die Ventilteller 6, 7 sind jeweils einstückig mit einem Ventilschaft 12, 13 verbunden. Die Ventilschäfte 12, 13 sind jeweils in Längsrichtung hin und her bewegbar geführt.In the FIGS. 1 to 4 is a positively controlled valve train 1 of an internal combustion engine, in particular a motor vehicle engine, shown in different views. The positively controlled valve train 1 serves to control the opening and closing movement of two valves 4, 5. The two valves 4, 5 each have a valve disk 6, 7, which serves to close a (not shown) opening in a working space of an internal combustion engine and specifically release. For the change of charge of the internal combustion engine, the control time cross sections are decisive, resulting from the product of open passage area and opening time. The closing movement direction of the valve disks 6, 7 is indicated by an arrow 9. The opening movement direction of the valve disks 6, 7 is indicated by an arrow 10. The valve disks 6, 7 are each integrally connected to a valve stem 12, 13. The valve stems 12, 13 are each guided back and forth in the longitudinal direction.

Im Bereich des freien Endes des Ventilschafts 13 sind zwei Bunde 15, 16 ausgebildet. Die Bunde 15, 16 weisen an ihren einander zugewandten Stirnseiten jeweils eine Anlagefläche auf. Die beiden Anlageflächen sind voneinander beabstandet. Zwischen den beiden Anlageflächen der Bunde 15, 16 sind zwei Kopplungselemente 18, 19 angeordnet, die den Ventilschaft 13 gabelartig umgreifen. Die Kopplungselemente 18, 19 sind einstückig mit einer Hebeleinrichtung 20 verbunden.In the region of the free end of the valve stem 13, two coils 15, 16 are formed. The collars 15, 16 each have a contact surface on their mutually facing end faces. The two contact surfaces are spaced apart. Between the two contact surfaces of the collars 15, 16 two coupling elements 18, 19 are arranged, which surround the valve stem 13 like a fork. The coupling elements 18, 19 are integrally connected to a lever device 20.

In Figur 3 sieht man, dass die Hebeleinrichtung 20 zwei Hebelarme 21, 22 aufweist, die von einem Grundkörper 23 der Hebeleinrichtung 20 ausgehen. An dem freien Ende des Hebelarms 21 sind, wie auch in Figur 4 zu sehen ist, die Kopplungselemente 18, 19 ausgebildet. Die Kopplungselemente 18, 19 haben jeweils die Gestalt einer mit einem Durchgangsloch versehenen Kreisscheibe, die an dem dem Hebelarm 21 abgewandten Ende abgeschnitten ist. In Figur 3 sieht man auch, dass von dem Grundkörper 23 der Hebeleinrichtung 20 zwei Lagerzapfen 24, 25 ausgehen, die dazu dienen, die Hebeleinrichtung 20 um eine Schwenkachse 26 herum schwenkbar zu lagern.In FIG. 3 it can be seen that the lever device 20 has two lever arms 21, 22, which originate from a base body 23 of the lever device 20. At the free end of the lever arm 21, as well as in FIG. 4 can be seen, the coupling elements 18, 19 formed. The coupling elements 18, 19 each have the shape of a circular disk provided with a through hole, which is cut off at the end facing away from the lever arm 21. In FIG. 3 it can also be seen that two bearing journals 24, 25 extend from the base body 23 of the lever device 20, which serve to pivotally mount the lever device 20 about a pivot axis 26.

Das Kopplungselement 19 weist einen Ansatz 29 auf, von dem etwa in Höhe des Bundes 16 auf der dem Bund 16 abgewandten Seite ein Antriebselement 30 ausgeht, das auch als Mitnehmerelement bezeichnet wird und die Gestalt eines kreiszylinderförmigen Zapfens aufweist. Das Antriebselement 30 ist einer Nockennut 32 angeordnet. Die Nockennut 32 weist einen Nutgrund 33 auf, der von einer Stirnfläche 34 eines Nockenelements 35 gebildet wird. Das Nockenelement 35 umfasst einen ersten Nocken 36, an dessen Umfang eine erste oder äußere Nockenkontur 41 mit einem ersten Grundkreis ausgebildet ist. Eine zweite oder innere Nockenkontur 42 mit einem zweiten Grundkreis, der koaxial beziehungsweise konzentrisch zu dem ersten Grundkreis der ersten Nockenkontur 41 angeordnet ist und einen kleineren Durchmesser als der erste Grundkreis aufweist, ist an einem zweiten Nocken 44 ausgebildet, der einstückig mit und erhaben zu dem ersten Nocken 36 des Nockenelements 35 ausgebildet ist.The coupling element 19 has a projection 29, from which approximately at the level of the collar 16 on the collar 16 side facing away from a drive element 30, which is also referred to as a driver element and has the shape of a circular cylindrical pin. The drive element 30 is arranged a cam groove 32. The cam groove 32 has a groove bottom 33, which from an end face 34 of a Cam member 35 is formed. The cam element 35 comprises a first cam 36, on whose circumference a first or outer cam contour 41 is formed with a first base circle. A second or inner cam contour 42 having a second base circle coaxially or concentric with the first base circle of the first cam contour 41 and having a smaller diameter than the first base circle is formed on a second cam 44 which is integral with and elevated to the second cam 44 first cam 36 of the cam member 35 is formed.

Von zweiten Nocken 44 geht ein Nockenwellenstummel 46 aus. Von der entgegengesetzten Stirnseite des Nockenelements 35 geht ein weiterer Nockenwellenstummel 47 aus, der koaxial zu dem Nockenwellenstummel 46 angeordnet ist. Die beiden Nockenwellenstummel 46, 47 können Teil einer Nockenwelle sein, durch welche der zwangsgesteuerte Ventiltrieb 1 angetrieben wird. Die Drehachse der Nockenwellenstummel 46, 47 ist in Figur 3 mit 45 bezeichnet.From second cam 44, a cam stub 46 goes out. From the opposite end face of the cam member 35 is another cam stub 47 goes out, which is arranged coaxially with the camshaft stub 46. The two cam stub 46, 47 may be part of a camshaft through which the positively controlled valve train 1 is driven. The axis of rotation of the camshaft stubs 46, 47 is in FIG. 3 designated 45.

Die erste äußere Nockenkontur 41 des Nockenelements 35 ist von einem Umschließungselement 48 umschlungen, das auch als Umschlingungselement bezeichnet wird. Bei dem Umschließungselement 48 handelt es sich um ein flexibles Band, das um den ersten Nocken 36, der auch als Außennocken oder äußerer Nocken bezeichnet wird, herum geschlungen und durch Reibschluss oder durch Formschluss auf diesem Nocken befestigt ist. Das Umschließungselement ragt in axialer Richtung über den äußeren Nocken 36 hinaus. Das Umschließungselement 48 steht soweit über den äußeren Nocken 36 hinaus, wie sich der zweite innere Nocken 44 in diese Richtung erstreckt. Der Überstand des Umschließungselements 48 entspricht also der Dicke des inneren Nockens 44 in axialer Richtung. Die zweite Nockenkontur 42 des inneren Nockens 44 bildet eine Nutflanke der Nockennut 32. Die andere Nutflanke wird von dem überstehenden Abschnitt des Umschließungselements 48 gebildet.The first outer cam contour 41 of the cam element 35 is looped around by an enclosing element 48, which is also referred to as a looping element. The enclosing member 48 is a flexible band wrapped around the first cam 36, also referred to as an outer cam or outer cam, and secured thereto by frictional engagement or positive engagement on this cam. The enclosing element projects beyond the outer cam 36 in the axial direction. The enclosing member 48 projects beyond the outer cam 36 as far as the second inner cam 44 extends in that direction. The projection of the enclosing element 48 thus corresponds to the thickness of the inner cam 44 in the axial direction. The second cam contour 42 of the inner cam 44 forms a groove flank of the cam groove 32. The other groove flank is formed by the protruding portion of the enclosing element 48.

In Figur 2 sieht man, dass das Umschließungselement 48 nicht von einem Endlosband gebildet wird, sondern zwei Enden aufweist, die durch ein Verschlusselement 55 aneinander befestigt sind. In Figur 2 sieht man auch, dass im Bereich des freien Endes des Ventilschafts 12 in gleicher Weise wie an dem Ventilschaft 13 zwei Bunde 65, 66 vorgesehen sind. Zwischen den Bunden 65, 66 sind zwei Kopplungselemente 68, 69 angeordnet, die einstückig mit der Hebeleinrichtung 20 verbunden sind. Das Kopplungselement 69 weist einen Ansatz 79 auf, von dem in gleicher Weise wie bei dem Ansatz 29 ein Antriebselement ausgeht, das in eine Nockennut eingreift, die analog zu der Nockennut 32 auf der entgegengesetzten Stirnseite des Nockenelements 35 vorgesehen ist.In FIG. 2 it can be seen that the encircling element 48 is not formed by an endless belt, but has two ends that pass through a closing element 55 attached to each other. In FIG. 2 one also sees that two collars 65, 66 are provided in the region of the free end of the valve stem 12 in the same way as on the valve stem 13. Between the collars 65, 66 two coupling elements 68, 69 are arranged, which are integrally connected to the lever device 20. The coupling element 69 has a projection 79 from which, in the same way as in the projection 29, a drive element extends, which engages in a cam groove which is provided analogously to the cam groove 32 on the opposite end face of the cam member 35.

Durch den erfindungsgemäßen Ventiltrieb können Performance-Steigerungen in Bezug auf den Ventilzeitquerschnitt und/oder eine höhere Enddrehzahl erreicht werden. Ein wesentlicher Vorteil des erfindungsgemäßen Ventiltriebs liegt darin, dass die Reibleistung des Ventiltriebs verringert werden kann. Dadurch kann insbesondere bei niedrigen Drehzahlen der Brennkraftmaschine der Kraftstoffverbrauch gesenkt werden. Die beiden Nockenkonturen des Nockenelements 35 werden zum Beispiel mit einem Profilwerkzeug oder in einem anderen formgebenden Verfahren, wie Gießen oder Sintern, in einem Arbeitsgang hergestellt. Der Grundkreisunterschied der beiden Nockenkonturen 41, 42 entspricht gerade dem Außendurchmesser des Antriebselements 30, das von einer Rolle gebildet werden kann.By means of the valve drive according to the invention, it is possible to achieve performance increases with respect to the valve time cross section and / or a higher end speed. A significant advantage of the valve drive according to the invention is that the friction of the valve train can be reduced. As a result, fuel consumption can be reduced, in particular at low engine speeds. The two cam contours of the cam element 35 are produced, for example, with a profile tool or in another shaping method, such as casting or sintering, in one operation. The base circle difference of the two cam contours 41, 42 corresponds exactly to the outer diameter of the drive element 30, which can be formed by a roller.

Claims (7)

  1. Desmodromic valve drive (1) for controlling the opening and closing movement of at least one valve device (4, 5), having at least one driven cam element (35) which has a first cam contour (41), with a first base circle around which is wrapped a wraparound element (48), and a second cam contour (42) with a second base circle which has a smaller diameter than the first base circle and which is arranged coaxially with respect to the first base circle in such a way that a cam groove (32) is formed between the wraparound element (48) and the second cam contour (42), into which cam groove (32) engages a drive element (30) which is coupled to the valve device (5), characterized in that the wraparound element (48) is formed separately as a flexible band which is fastened to the first cam contour (41).
  2. Desmodromic valve drive according to Claim 1, characterized in that the drive element (30) has the shape of a circular cylinder whose outer diameter corresponds to the spacing between the two base circles.
  3. Desmodromic valve drive according to one of the preceding claims, characterized in that the drive element (30) is coupled by means of a lever device (20) to at least one coupling element (18, 19) which is coupled by means of the lever device (20) to a valve shank (13) of the valve device (5).
  4. Desmodromic valve drive according to Claim 3, characterized in that the coupling element (18, 19) is arranged between two collars (15, 16) which are attached to the valve shank (13).
  5. Desmodromic valve drive according to Claim 3 or 4, characterized in that the lever device (20) is pivotably mounted at an end remote from the coupling element (18, 19).
  6. Desmodromic valve drive according to one of the preceding claims, characterized in that the cam element (35) has, on two sides, in each case one first cam contour (41) with a first base circle, with the wraparound element (48) being wrapped around the two first cam contours, and in each case one second cam contour (42) with a second base circle which has a smaller diameter than the first base circle and which is arranged coaxially with respect to the first base circle in such a way that in each case one cam groove (32) is formed between the wraparound element (48) and the two second cam contours (42), into which cam groove (32) engages in each case one drive element (30) which is coupled to in each case one valve device (5, 4).
  7. Desmodromic valve drive according to Claim 6, characterized in that the drive elements (30) are connected by means of the lever device (20) to in each case at least one coupling element (18, 19, 68, 69) which is coupled in each case to a valve shank (13, 12) of the valve devices (5, 4).
EP20060009750 2005-08-13 2006-05-11 Desmodromic valve drive Expired - Fee Related EP1752622B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE200510038505 DE102005038505B3 (en) 2005-08-13 2005-08-13 Forced-control valve train

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EP1752622A1 EP1752622A1 (en) 2007-02-14
EP1752622B1 true EP1752622B1 (en) 2009-07-22

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110303174A1 (en) * 2009-03-06 2011-12-15 Toyota Jidosha Kabushiki Kaisha Variable valve apparatus of internal combustion engine

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Publication number Priority date Publication date Assignee Title
GB191319193A (en) * 1913-08-23 1914-06-18 Samuel White And Company Ltd J Improvements in Means for Operating Valves of Internal Combustion Engines.
US1280912A (en) * 1916-08-01 1918-10-08 Floyd Waterman Cam for internal-combustion engines.
US1238175A (en) * 1917-04-09 1917-08-28 Hulbert S Clark Elastic puppet-valve.
US1644059A (en) * 1921-08-01 1927-10-04 Holle Joseph Valve-actuating mechanism
GB516746A (en) * 1938-07-07 1940-01-10 Cecil Newman James Glass Improvements in or relating to valve actuating mechanisms for internal combustion engines
GB741831A (en) * 1953-02-03 1955-12-14 Kelston Engineering Company Lt An improved operating mechanism for lift valves
DE1203538B (en) * 1959-02-21 1965-10-21 Luigi Zanini Inevitably cam operated valve control for internal combustion engines
DE3700715A1 (en) * 1986-01-22 1987-07-23 Volkswagen Ag Positive control for a valve
JPS63129109A (en) * 1986-11-17 1988-06-01 Tsuneaki Takahashi Valve system for engine
GB2237324A (en) * 1989-10-28 1991-05-01 Raymond Joseph Huber Desnodromic valve-actuation mechanism
EP1247946A3 (en) * 2001-03-26 2002-12-04 Stefan Battlogg Valve drive

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110303174A1 (en) * 2009-03-06 2011-12-15 Toyota Jidosha Kabushiki Kaisha Variable valve apparatus of internal combustion engine
US8813698B2 (en) * 2009-03-06 2014-08-26 Toyota Jidosha Kabushiki Kaisha Variable valve apparatus of internal combustion engine

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DE102005038505B3 (en) 2007-03-22
DE502006004287D1 (en) 2009-09-03
EP1752622A1 (en) 2007-02-14

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