EP0462853B1 - Variable amplitude device for the lift of at least one internal combustion engine valve - Google Patents

Variable amplitude device for the lift of at least one internal combustion engine valve Download PDF

Info

Publication number
EP0462853B1
EP0462853B1 EP91401347A EP91401347A EP0462853B1 EP 0462853 B1 EP0462853 B1 EP 0462853B1 EP 91401347 A EP91401347 A EP 91401347A EP 91401347 A EP91401347 A EP 91401347A EP 0462853 B1 EP0462853 B1 EP 0462853B1
Authority
EP
European Patent Office
Prior art keywords
lever
valve
cam
contact
pivot
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
EP91401347A
Other languages
German (de)
French (fr)
Other versions
EP0462853A1 (en
Inventor
Bruno Silondi
Luc Schab
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Automobiles Peugeot SA
Automobiles Citroen SA
Original Assignee
Automobiles Peugeot SA
Automobiles Citroen SA
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.)
Filing date
Publication date
Application filed by Automobiles Peugeot SA, Automobiles Citroen SA filed Critical Automobiles Peugeot SA
Publication of EP0462853A1 publication Critical patent/EP0462853A1/en
Application granted granted Critical
Publication of EP0462853B1 publication Critical patent/EP0462853B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
    • F01L13/0036—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
    • 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
    • F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
    • F01L1/265—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder peculiar to machines or engines with three or more intake valves per cylinder
    • 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
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
    • F01L13/0021—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of rocker arm ratio
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/20—SOHC [Single overhead camshaft]

Definitions

  • the present invention relates to a variable amplitude device for lifting at least one valve of an internal combustion engine.
  • Valve lifting devices have been known for a long time in which the movement of a control cam secured to a camshaft of the engine is transmitted to a valve stem by means of a rocker arm or a lever, the one end is pivotally mounted on the cylinder head and the other end of which is interposed between the control cam and the free end of the valve stem, in order to alternatively exert or not an axial thrust on the latter.
  • connection of the two pivots to the cylinder head and of the levers to the valve uses a large number of moving parts and does not make it possible to apply a force directed along its axis on the valve.
  • document DE-A-3 119 133 describes a device corresponding to the preamble of the independent claims 1, 3 and 6.
  • the invention aims to overcome these drawbacks by proposing a simple device, making it possible to act on one or more valves in their axial direction, and without having to resort to hydraulic controls or to cantilevered parts.
  • the subject of the invention is a device with variable lifting amplitude for at least one valve of an internal combustion engine, and of the type comprising a control shaft with two cams, one of which is high and the other is lower, a lever provided to the right of each control cam, the two levers extending approximately in parallel with each a portion which is articulated on the cylinder head by means of a pivot and one end which is connected to the valve so as to be able to exert an axial thrust on the latter, against a return spring of the valve, one of the pivots being mounted movable, according to operating parameters of the engine and under the effect of a selection member between an active position in which the associated lever cooperates with the corresponding cam and a retracted position, each lever being capable of movement between a working position in contact with its control cam and a pos erased ition, so that the two levers act alternately and selectively on the valve, one of them acting on the latter by means of the other lever in the erased position, cooperating by a bearing surface with the end of
  • the high cam can cooperate with a straight lever or latch which extends between two guide faces of the above-mentioned parallel branches, said latch being mounted on the cylinder head by means of a movable pivot fixed on a sliding guide. and comprising a contact finger with a bearing surface which extends on its lower face, in line with the abovementioned transverse part.
  • the invention relates to a device with variable amplitude of lift for at least one valve of an internal combustion engine, and of the type comprising a control shaft with two cams, one of which is high and l the other is low, a lever provided to the right of each control cam, the two levers extending roughly in parallel with each a portion which is articulated on the cylinder head by means of a pivot and one end which is connected to the valve so as to be able to exert an axial thrust on the latter, against a return spring of the valve, one of the pivots being mounted movable, according to operating parameters of the engine and under the effect of a selection member between an active position in which the associated lever cooperates with the corresponding cam and a retracted position, each lever being capable of movement between a working position in contact with its c control core and an erased position, so that the two levers act alternately and selectively on the valve, one of them acting on the latter by means of the other lever in the erased position, cooperating by a bearing surface with the end
  • the transverse part of the T-shaped lever may have at its lower face two contact surfaces with two valves and which are provided in line with the bearing surfaces of the catches.
  • each straight latch is mounted on a fixed pivot and has at its free end a contact finger which projects from the latch, in line with one of the abovementioned bearing surfaces.
  • the invention relates to a device with variable amplitude of lift for at least one valve of an internal combustion engine, and of the type comprising a control shaft with two cams, one of which is high and the other is low, a lever provided at the right of each control cam, the two levers extending roughly in parallel with each a portion which is articulated on the cylinder head by means of a pivot and one end which is connected to the valve so as to be able to exert an axial thrust on the latter, against a return spring of the valve, one of the pivots being mounted movable, according to engine operating parameters and under the effect of a selection member between an active position in which the associated lever cooperates with the corresponding cam and a retracted position, each lever being capable of movement between a working position in contact with ec its control cam and an erased position, so that the two levers act alternately and selectively on the valve, one of them acting on the latter by means of the other lever in the erased position, by cooperating by a bearing surface with the end of
  • an elastic member can be fixed to each fixed pivot and exert on the corresponding lever a force tending to apply said lever against the associated cam.
  • Figure 1 is a vertical sectional view along the longitudinal axis of the movable pivot lever, of a valve lifting device according to the invention.
  • FIG. 2 represents the device visible in FIG. 1 in vertical section and along the line II-II of FIG. 1.
  • Figures 3 and 4 are simplified views similar to Figure 1 of the device according to the invention, in the working positions and cleared from the movable pivot lever, respectively.
  • FIG. 5 is a view in vertical section and along the line V-V of FIG. 1.
  • FIG. 6 is a plan view and along arrow VI-VI of FIG. 5 of the levers with fixed pivot and with movable pivot of the device visible in FIGS. 1 to 5.
  • Figure 7 is a view similar to Figure 1 illustrating a second embodiment of the invention.
  • FIGS. 8 and 9 are views similar to FIGS. 3 and 4 respectively, and which represent the device visible in FIG. 7.
  • FIG. 10 is a view similar to FIG. 5 and illustrating the levers with fixed pivots and with movable pivot visible in FIGS. 7 to 9.
  • Figure 11 is a plan view and along arrow XI of Figure 10, levers with fixed pivots and movable pivot of the second embodiment of the device according to the invention.
  • Figure 12 is a sectional view along a vertical plane intersecting the longitudinal axis of the selection shaft of a device according to a third embodiment of the invention.
  • FIG. 13 is a view in vertical section and along the line XIII-XIII of FIG. 12.
  • Figures 14 and 15 are views similar to Figure 13 and in which the movable pivot lever is in the working position and in the retracted position, respectively.
  • FIG. 16 is a view in vertical section and along the line XVI-XVI of FIG. 13.
  • Figure 17 is a plan view and along arrow XVII of Figure 16, which illustrates the fixed pivot and movable pivot levers of the third embodiment of the invention.
  • Figure 18 is a schematic view illustrating a device control system according to the invention.
  • FIGS. 1 and 2 show a part of the cylinder head 1 of an internal combustion engine of any type, in which part a valve 2 is slidably mounted along the longitudinal axis of its rod 2a.
  • the lower part of the valve stem 2a is guided in a barrel 3, and its upper part has a groove 2b, on which is fixed a cup 4.
  • a second cup 5 is mounted around a part of the barrel 3 which projects of the cylinder head 1, so as to receive coaxially with the rod 2a a return spring 6 which exerts on the valve 2 a force tending to move the cup 4 away from the cup 5.
  • the lifting device with variable amplitude according to the invention makes it possible to act on two valves marked at 2 and which are each equipped with cups 4 and 5, as well as return springs 6.
  • the reference numeral 7 designates a control shaft driven in rotation, of which three eccentric cams are integral and designated by the references H and B.
  • Two cams B having identical low profiles are arranged on the shaft 7 , on either side of a cam H which has a high profile, that is to say the profile of the guide path as visible for example in Figure 1, is more strongly projecting from the shaft 7, compared to the low cams B.
  • Two levers in the form of latches and generally designated by the references F and M extend to the right of the cams B and H, respectively. Referring to Figures 5 and 6, we see that the latch F has substantially the shape of an O with two parallel branches 8 and 9 which extend in the longitudinal direction of the latch F.
  • the parallel branches 8 and 9 of the latch F are connected to each other by their ends on one side by a transverse part 10 which extends substantially parallel to the axis of rotation of the shaft 7, and on the other side by a bent part 11.
  • a dotted lever in FIGS. 6 and 7 illustrates a straight lever or latch M which extends in a direction parallel to the branches 8 and 9, and which is arranged between two guide surfaces 22 and 23 of the branches 8 and 9 , respectively.
  • the latch M has at its free end a contact finger 12 on the underside of which is formed a support surface S which extends in line with the transverse part 10 of the lever F.
  • spherical bearings 8a, 9a and Ma are formed, respectively in the branches 8, 9 and in the latch M, pivots 13, 14 and 15 being respectively housed in these bearing surfaces.
  • the reference numeral 24 designates a cylindrical guide, which is slidably mounted in a bore 1a of the cylinder head and into which the pivot 15 is screwed, using a lock nut 26.
  • the bore opens into a housing 1b of the cylinder head, which extends substantially parallel to the axis of rotation of the control shaft 7.
  • a shaft 25 is pivotally mounted in this housing 1b and comprises, with regard to the the bore 1a, a selection cam 27 of the active or retracted position of the guide assembly 24 - pivot 15.
  • a single selection shaft may comprise several selection cams, located at intervals corresponding to the location of other valve lift devices of the same engine.
  • the selection shaft can for example be connected to a stepping motor (not shown) or to a transmission mechanism such as a gear or a synchronous belt (not shown), and which is connected to the shaft control via an electromagnetic clutch.
  • the drive of the drive shaft selection is carried out by a mechanism allowing a revolution of the control shaft to correspond to a half-revolution of the selection shaft, so that the amplitude change of the valve lift takes place, as explained below -after, on a half-turn of the selection shaft and so that the first pivot actuated by the shaft has already changed state (active-retracted) when we start to change the state of the last pivot operated by the same selection shaft.
  • the drive of the selection shaft may be triggered manually, mechanically or electronically, depending on engine operating parameters. Illustrated in FIG. 18 is an example of an electronic control system for the change in amplitude of the valve lift 2.
  • This trigger system mainly consists of a housing 30 which is firstly connected to a mechanism for drive (not shown) of the selection shaft, so as to provide it with control signals, as a function of engine operating status signals, which come from sensors to which the housing 30 is also connected.
  • FIG. 3 shows the device in an active position of the movable pivot 15 around which the lever M is articulated.
  • the selection cam 27 of the shaft 25 is oriented so that the most eccentric part of this cam either in contact with the lower face of the guide 24, so that the guide 24 - pivot 15 assembly is strongly projecting from the upper face of the cylinder head 1 where the bore 1A opens.
  • the latch M With the pivot 15 in the active position, the latch M is in the working position, that is to say is in contact by its convex surface 35 with the control cam H, under the effect of the force exerted by the spring. 6 (not shown in FIGS. 3 and 4), which acts on the valves 2 and on the transverse part 10 of the lever F acting as an intermediary between the spring and the bearing surface S of the contact finger 12.
  • the housing 30 will deliver a trigger signal of the drive mechanism of the selection shaft 25, so that the latter pivots to the angular position visible in FIG. 4.
  • the device according to the invention advantageously takes advantage of the connection by simply pressing the levers M and F together to allow an "adaptation" of the lever F in the working position under the effect of the spring 6 so that the lever F cooperates with the low profile B cams.
  • each lever is capable of movement between a working position in contact with the control cam and a cleared position, so that the levers act alternately and selectively on the valves according to engine operating parameters.
  • the transverse part 10 of the lever F and the contact finger 12 of the lever M one of the latches is in the retracted position when the other is in the working position, without the two catches being articulated by means of pivots sliding in the cylinder head 1.
  • each low cam B of the shaft 7 differs mainly from the first by the fact that at the right of each low cam B of the shaft 7 are arranged straight levers 8 and 9. These levers have the form of latches and are articulated by relative to the cylinder head 1 using the fixed pivots 13 and 14, respectively.
  • Each latch 8, 9 has at its end opposite its swiveling connection, a contact finger, one of which is marked at 38 and the other at 39.
  • each of these lugs 8 and 9 has at its upper part a convex surface 20, 21, able to cooperate by contact with one of the low cams B.
  • a lever M having the shape of a T, with a convex surface 35 able to cooperate by contact with the cam H.
  • the longitudinal branch of the lever M which constitutes the vertical bar of the T is articulated on a pivot 15 - guide 24 assembly, which slides in the cylinder head 1.
  • a transverse part 10 of the lever M extends substantially parallel to the axis of rotation of the shafts 7 and 25, to the right of the contact fingers 38 and 39 straight latches 8 and 9.
  • Each end of the transverse part 10 has at its part lower a convex pad 18, 19, forming a contact surface so that each end of this part 10 of the lever M rests on one of the valves 2. It can be seen in FIG.
  • the crossbar 10 that the crossbar 10 has at its upper part and in line with the contact pads 18 and 19 of the bearing surfaces S.
  • the longitudinal part of the lever M extends between two guide faces 22 and 23 of the straight levers 8 and 9, respectively, while the contact fingers 38 and 39 are in turn positioned laterally by flanges 37 which project from the upper face of the transverse part 10 of the lever M, from an outer edge of each of the bearing surfaces S, which allows lateral positioning of all three levers.
  • the reference numeral 48 designates an elastic member which is constituted by a metal blade and elastically deformable. Although only one of these members is shown, the device visible in FIGS. 7 to 11 comprises two of these members 48, the free end of each of which bears against the underside of one of the lugs 8 or 9 , so as to exert on it a force tending to press it against the corresponding cam B. The other end of each of these members 48 is fixed to the cylinder head 1 by means of one of the locknuts 16 and 17 which is screwed onto one of the fixed pivots 13, 14.
  • FIG. 8 illustrates the device according to the invention with the lever M in the working position, under the effect on the one hand of the movable pivot 15 which is placed in the active position by the selection cam 27, and on the other hand under the effect of the high cam H which is in contact with the convex surface 35. Thanks to the force exerted by the return springs 6 (not shown), the valves 2 come to bear against the contact surfaces 18 and 19 of the transverse part 10 of the lever M. In the position illustrated in FIG. 8, a large amplitude is obtained from the lifting of the valves 2 which are directly displaced by the convex pads 18 and 19 of the lever M.
  • the change in amplitude of the lifting of the valves 2 is effected by the rotation of the shaft 25, and when the control cams B and H have their backs facing the surfaces 20, 21 and 35. This rotation places the device in the state visible in FIG. 9.
  • FIG. 9 therefore represents the device with the lever M in its erased position, that is to say with the back of the selection cam 27 facing the sliding guide 24.
  • the contact fingers 38 and 39 of the latches 8 and 9 are pressed against the effect of the cams B, against the bearing surfaces S of the transverse part 10 of the lever M, so that the latter transmits the movement of the latches 8 and 9 to the valves 2.
  • the lever M is moved away from the cam H when the shaft 7 rotates, therefore has no action on the valve stems 2.
  • FIGS. 12 to 17 show a third embodiment of the invention, for which the same reference numbers as those of the preceding embodiments designate similar or identical parts or elements, and which consequently will not need to be described again.
  • the control shaft 7 comprises a single low profile cam B and two high profile cams H which are arranged on either side of the cam B.
  • Each cam H cooperates with one of of them straight levers or latches 58 and 59 which are articulated on the cylinder head 1 by means of mobile pivots 15.
  • These pivots 15 are fixed to guides 24 which each slide in a bore 1a of the cylinder head 1 and which open at right angle a shaft 25 which is pivotally mounted and on which two cams 27 for selecting between a retracted position and an active position of the two guide 24 - pivot 15 assemblies are formed.
  • each of the latches 58 and 59 has a contact finger 38 and 39, respectively.
  • the contact fingers 38 and 39 have at their lower part convex pads 18 and 19 respectively, which allow the contact of the valves 2 with the latches 58 and 59, while allowing their displacement by sliding during changes in amplitude of the lift .
  • At the upper part of each contact finger 38, 39 extends a bearing surface S, able to cooperate with a lever F with a pivot pivoted relative to the cylinder head 1.
  • the lever F has the shape of a T and extends between two guide surfaces 22 and 23 of the latches 58 and 59 respectively, these surfaces being located facing each other and making it possible to guide the side latch F.
  • the lever F is mounted on the cylinder head 1 by means of a fixed pivot 13 and a lock nut 16.
  • a transverse part 10 of the lever F extends substantially along a direction parallel to the axis of rotation of the shafts 7 and 25, with each of its ends coming to the right of one of the contact fingers 38 or 39.
  • a single elastic member has been located at 48 which is constituted by a metal blade fixed to the cylinder head 1 using the pivot 13 and the lock nut 16, while its free end comes into contact with the underside of the longitudinal part of the lever T, so as to exert on this lever a force tending to press the latter against the corresponding cam B.
  • the latches 58 and 59 are placed, as visible in FIG. 15, in their retracted position, so that the ends of the transverse part 10 of the lever F come into contact with surfaces S support of the contact fingers 38 and 39 of the latches 58 and 59, and so that the latter transmit to the valves 2 the movement of the lever F which is caused by the low profile cam B.
  • valve lift device with variable amplitude is simple and thanks to which the change in amplitude of the lift is obtained with one of the levers articulated on a fixed pivot.
  • this device makes it easier to adjust the functional clearances and also makes it possible to act on the valves without overhang.
  • the device according to the invention can also allow the lifting of a single valve, the stem of which would preferably come into contact with the middle of the transverse part described above.

Description

La présente invention se rapporte à un dispositif à amplitude variable pour la levée d'au moins une soupape de moteur à combustion interne.The present invention relates to a variable amplitude device for lifting at least one valve of an internal combustion engine.

On connaît depuis longtemps des dispositifs de levée de soupape dans lesquels le mouvement d'une came de commande solidaire d'un arbre à cames du moteur est transmis à une tige de soupape par l'intermédiaire d'un culbuteur ou d'un levier dont une extrémité est montée pivotante sur la culasse et dont l'autre extrémité est interposée entre la came de commande et l'extrémité libre de la tige de soupape, afin d'alternativement exercer ou non une poussée axiale sur cette dernière.Valve lifting devices have been known for a long time in which the movement of a control cam secured to a camshaft of the engine is transmitted to a valve stem by means of a rocker arm or a lever, the one end is pivotally mounted on the cylinder head and the other end of which is interposed between the control cam and the free end of the valve stem, in order to alternatively exert or not an axial thrust on the latter.

Toutefois, ces dispositifs ne permettent pas de faire varier l'amplitude de la levée de soupape en fonction de paramètres de fonctionnement du moteur, tels que la charge et le régime de celui-ci.However, these devices do not make it possible to vary the amplitude of the valve lift as a function of engine operating parameters, such as the load and the speed thereof.

C'est pourquoi on a proposé par exemple dans le document FR-A-2 506 834 des dispositifs comprenant deux cames montées sur un même arbre de commande, l'une présentant un profil haut et l'autre présentant un profil bas.This is why, for example, in document FR-A-2 506 834, devices have been proposed comprising two cams mounted on the same control shaft, one having a high profile and the other having a low profile.

Cependant, avec ces dispositifs de l'art antérieur, la liaison des deux pivots à la culasse et des leviers à la soupape utilise un grand nombre de pièces en mouvement et ne permet pas d'appliquer sur la soupape un effort dirigé suivant son axe.However, with these devices of the prior art, the connection of the two pivots to the cylinder head and of the levers to the valve uses a large number of moving parts and does not make it possible to apply a force directed along its axis on the valve.

D'autres dispositifs connus comportent des moyens commandés de solidarisation de deux leviers ou culbuteurs respectivement associés à une came haute et à une came basse. Ces moyens, qui sont en général hydrauliques comme dans GB-A-2 199 079, sont relativement complexes et coûteux.Other known devices include controlled means for securing two levers or rockers respectively associated with a high cam and a low cam. These means, which are generally hydraulic as in GB-A-2 199 079, are relatively complex and expensive.

Pour sa part, le document DE-A-3 119 133 décrit un dispositif correspondant au préambule des revendications indépendantes 1,3 et 6.For its part, document DE-A-3 119 133 describes a device corresponding to the preamble of the independent claims 1, 3 and 6.

En outre, les documents EP-A-405 927 et WO 91/12 415 font partie de l'état de la technique antérieur à la présente invention, selon l'article 54 (3) de la CBE. Toutefois, les dispositifs décrits dans ces documents soit ne permettent pas d'agir sur les soupapes sans porte-à-faux, soit sont relativement complexes de sorte que le réglage de leurs jeux fonctionnels n'est pas aisé.In addition, documents EP-A-405 927 and WO 91/12 415 form part of the state of the art prior to the present invention, according to Article 54 (3) of the EPC. However, the devices described in these documents either do not allow acting on the valves without overhang, or are relatively complex so that the adjustment of their functional clearances is not easy.

L'invention a pour but de pallier ces inconvénients en proposant un dispositif simple, permettant d'agir sur une ou plusieurs soupapes suivant leur direction axiale, et sans avoir à recourir à des commandes hydrauliques ou à des pièces en porte-à-faux.The invention aims to overcome these drawbacks by proposing a simple device, making it possible to act on one or more valves in their axial direction, and without having to resort to hydraulic controls or to cantilevered parts.

A cet effet, l'invention a pour objet un dispositif à amplitude variable de levée pour au moins une soupape de moteur à combustion interne, et du type comprenant un arbre de commande avec deux cames dont l'une est haute et l'autre est basse, un levier prévu au droit de chaque came de commande, les deux leviers s'étendant à peu près parallèlement avec chacun une portion qui est articulée sur la culasse par l'intermédiaire d'un pivot et une extrémité qui est reliée à la soupape de façon à pouvoir exercer une poussée axiale sur cette dernière, à l'encontre d'un ressort de rappel de la soupape, l'un des pivots étant monté mobile, en fonction de paramètres de fonctionnement du moteur et sous l'effet d'un organe de sélection entre une position active dans laquelle le levier associé coopère avec la came correspondante et une position escamotée, chaque levier étant susceptible d'un mouvement entre une position de travail en contact avec sa came de commande et une position effacée, de façon que les deux leviers agissent alternativement et sélectivement sur la soupape, l'un d'eux agissant sur celle-ci par l'intermédiaire de l'autre levier en position effacée, en coopérant par une surface d'appui avec l'extrémité de ce levier qui est en contact avec la soupape, caractérisé en ce que, ladite portion articulée de chaque levier sur la culasse étant son extrémité opposée à celle qui est reliée à la soupape, l'arbre de commande comporte une troisième came présentant un profil identique à celui de la came basse qui est disposée de façon que la came haute soit située entre les deux cames à profil bas, et que chaque came basse coopère respectivement avec l'une des deux branches parallèles d'un levier en forme de 0 qui est monté sur deux pivots fixes et qui comporte au moins une surface d'appui avec au moins une soupape, cette surface étant formée à la face inférieure d'une partie transversale du levier en forme de 0 et qui relie les deux branches parallèles d'un côté ainsi qu'une partie coudée les reliant de l'autre côté.To this end, the subject of the invention is a device with variable lifting amplitude for at least one valve of an internal combustion engine, and of the type comprising a control shaft with two cams, one of which is high and the other is lower, a lever provided to the right of each control cam, the two levers extending approximately in parallel with each a portion which is articulated on the cylinder head by means of a pivot and one end which is connected to the valve so as to be able to exert an axial thrust on the latter, against a return spring of the valve, one of the pivots being mounted movable, according to operating parameters of the engine and under the effect of a selection member between an active position in which the associated lever cooperates with the corresponding cam and a retracted position, each lever being capable of movement between a working position in contact with its control cam and a pos erased ition, so that the two levers act alternately and selectively on the valve, one of them acting on the latter by means of the other lever in the erased position, cooperating by a bearing surface with the end of this lever which is in contact with the valve, characterized in that, said articulated portion of each lever on the cylinder head being its end opposite to that which is connected to the valve, the control shaft comprises a third cam having a profile identical to that of the low cam which is arranged so that the high cam is located between the two low profile cams, and that each low cam cooperates respectively with one of the two parallel branches of a shaped lever from 0 which is mounted on two fixed pivots and which comprises at least one bearing surface with at least one valve, this surface being formed on the underside of a transverse part of the 0-shaped lever and which connects the two parallel branches on one side as well as a bent part connecting them on the other side.

Dans ce cas, la came haute peut coopèrer avec un levier droit ou linguet qui s'étend entre deux faces de guidage des branches parallèles précitées, ledit linguet étant monté sur la culasse par l'intermédiaire d'un pivot mobile fixé sur un guide coulissant et comportant un doigt de contact avec une surface d'appui qui s'étend sur sa face inférieure, au droit de la partie transversale précitée.In this case, the high cam can cooperate with a straight lever or latch which extends between two guide faces of the above-mentioned parallel branches, said latch being mounted on the cylinder head by means of a movable pivot fixed on a sliding guide. and comprising a contact finger with a bearing surface which extends on its lower face, in line with the abovementioned transverse part.

Suivant un autre mode de réalisation, l'invention a pour objet un dispositif à amplitude variable de levée pour au moins une soupape de moteur à combustion interne, et du type comprenant un arbre de commande avec deux cames dont l'une est haute et l'autre est basse, un levier prévu au droit de chaque came de commande, les deux leviers s'étendant à peu près parallèlement avec chacun une portion qui est articulée sur la culasse par l'intermédiaire d'un pivot et une extrémité qui est reliée à la soupape de façon à pouvoir exercer une poussée axiale sur cette dernière, à l'encontre d'un ressort de rappel de la soupape, l'un des pivots étant monté mobile, en fonction de paramètres de fonctionnement du moteur et sous l'effet d'un organe de sélection entre une position active dans laquelle le levier associé coopère avec la came correspondante et une position escamotée, chaque levier étant susceptible d'un mouvement entre une position de travail en contact avec sa came de commande et une position effacée, de façon que les deux leviers agissent alternativement et sélectivement sur la soupape, l'un d'eux agissant sur celle-ci par l'intermédiaire de l'autre levier en position effacée, en coopérant par une surface d'appui avec l'extrémité de ce levier qui est en contact avec la soupape, caractérisé en ce que, ladite portion articulée sur la culasse de chaque levier étant son extrémité opposée à celle qui est reliée à la soupape, la came haute coopère avec un levier en forme de T, dont la branche longitudinale est articulée sur un pivot coulissant et dont la partie transversale comporte à sa face supérieure deux surfaces d'appui pour deux linguets qui coopèrent respectivement avec l'une des cames basses et comporte à sa face inférieure au moins une surface de contact avec au moins une soupape.According to another embodiment, the invention relates to a device with variable amplitude of lift for at least one valve of an internal combustion engine, and of the type comprising a control shaft with two cams, one of which is high and l the other is low, a lever provided to the right of each control cam, the two levers extending roughly in parallel with each a portion which is articulated on the cylinder head by means of a pivot and one end which is connected to the valve so as to be able to exert an axial thrust on the latter, against a return spring of the valve, one of the pivots being mounted movable, according to operating parameters of the engine and under the effect of a selection member between an active position in which the associated lever cooperates with the corresponding cam and a retracted position, each lever being capable of movement between a working position in contact with its c control core and an erased position, so that the two levers act alternately and selectively on the valve, one of them acting on the latter by means of the other lever in the erased position, cooperating by a bearing surface with the end of this lever which is in contact with the valve, characterized in that, said articulated portion on the cylinder head of each lever being its end opposite to that which is connected to the valve, the high cam cooperates with a T-shaped lever, the longitudinal branch of which is articulated on a sliding pivot and the transverse part of which comprises on its upper face two bearing surfaces for two catches which cooperate respectively with one of the cams low and has on its underside at least one contact surface with at least one valve.

Dans ce cas, la partie transversale du levier en forme de T peut comporter à sa face inférieure deux surfaces de contact avec deux soupapes et qui sont prévues au droit des surfaces d'appui des linguets.In this case, the transverse part of the T-shaped lever may have at its lower face two contact surfaces with two valves and which are provided in line with the bearing surfaces of the catches.

Avantageusement, chaque linguet droit est monté sur un pivot fixe et comporte à son extrémité libre un doigt de contact qui fait saillie du linguet, au droit de l'une des surfaces d'appui précitées.Advantageously, each straight latch is mounted on a fixed pivot and has at its free end a contact finger which projects from the latch, in line with one of the abovementioned bearing surfaces.

Suivant encore un autre mode de réalisation, l'invention a pour objet un dispositif à amplitude variable de levée pour au moins une soupape de moteur à combustion interne, et du type comprenant un arbre de commande avec deux cames dont l'une est haute et l'autre est basse, un levier prévu au droit de chaque came de commande, les deux leviers s'étendant à peu près parallèlement avec chacun une portion qui est articulée sur la culasse par l'intermédiaire d'un pivot et une extrémité qui est reliée à la soupape de façon à pouvoir exercer une poussée axiale sur cette dernière, à l'encontre d'un ressort de rappel de la soupape, l'un des pivots étant monté mobile, en fonction de paramètres de fonctionnement du moteur et sous l'effet d'un organe de sélection entre une position active dans laquelle le levier associé coopère avec la came correspondante et une position escamotée, chaque levier étant susceptible d'un mouvement entre une position de travail en contact avec sa came de commande et une position effacée, de façon que les deux leviers agissent alternativement et sélectivement sur la soupape, l'un d'eux agissant sur celle-ci par l'intermédiaire de l'autre levier en position effacée, en coopérant par une surface d'appui avec l'extrémité de ce levier qui est en contact avec la soupape, caractérisé en ce que, ladite portion articulée sur la culasse de chaque levier étant son extrémité opposée à celle qui est reliée à la soupape, l'arbre de commande comporte une troisième came présentant un profil identique à celui de la came haute et qui est disposée de façon que la came basse soit située entre deux cames à profil haut, ladite came à profil bas coopérant avec l'un des leviers en forme de T qui est articulée sur un pivot fixe et dont la partie transversale s'étend jusqu'au droit de deux soupapes, selon chaque came haute coopère avec un levier droit ou linguet dont une extrémité est montée sur un pivot coulissant dans la culasse, et dont l'autre extrémité comporte un doigt de contact qui présente à sa face inférieure une surface de contact pour l'une des soupapes, et présente à sa face supérieure une surface d'appui pour l'une des extrémités de la partie transversale du levier en forme de T.According to yet another embodiment, the invention relates to a device with variable amplitude of lift for at least one valve of an internal combustion engine, and of the type comprising a control shaft with two cams, one of which is high and the other is low, a lever provided at the right of each control cam, the two levers extending roughly in parallel with each a portion which is articulated on the cylinder head by means of a pivot and one end which is connected to the valve so as to be able to exert an axial thrust on the latter, against a return spring of the valve, one of the pivots being mounted movable, according to engine operating parameters and under the effect of a selection member between an active position in which the associated lever cooperates with the corresponding cam and a retracted position, each lever being capable of movement between a working position in contact with ec its control cam and an erased position, so that the two levers act alternately and selectively on the valve, one of them acting on the latter by means of the other lever in the erased position, by cooperating by a bearing surface with the end of this lever which is in contact with the valve, characterized in that, said articulated portion on the cylinder head of each lever being its end opposite to that which is connected to the valve, the control shaft comprises a third cam having a profile identical to that of the high cam and which is arranged so that the low cam is located between two high profile cams, said low profile cam cooperating with one of the shaped levers of T which is articulated on a fixed pivot and whose transverse part extends to the right of two valves, according to each high cam cooperates with a straight lever or latch, one end of which is mounted on a pivot sliding in the cylinder head, and the other end of which has a contact finger which has on its underside a contact surface for one of the valves, and has on its upper face a bearing surface for one of the ends of the transverse part of the T-shaped lever.

Alors, un organe élastique pourra être fixé à chaque pivot fixe et exercer sur le levier correspondant une force ayant tendance à appliquer ledit levier contre la came y associée.Then, an elastic member can be fixed to each fixed pivot and exert on the corresponding lever a force tending to apply said lever against the associated cam.

Mais d'autres avantages et particularités de l'invention apparaîtront mieux dans la description détaillée qui suit et se réfère aux dessins annexés, donnés uniquement à titre d'exemple, et dans lesquels:However, other advantages and particularities of the invention will appear better in the detailed description which follows and which refers to the appended drawings, given solely by way of example, and in which:

La figure 1 est une vue en coupe verticale suivant l'axe longitudinal du levier à pivot mobile, d'un dispositif de levée de soupape suivant l'invention.Figure 1 is a vertical sectional view along the longitudinal axis of the movable pivot lever, of a valve lifting device according to the invention.

La figure 2 représente le dispositif visible sur la figure 1 en coupe verticale et suivant la ligne II-II de la figure 1.FIG. 2 represents the device visible in FIG. 1 in vertical section and along the line II-II of FIG. 1.

Les figures 3 et 4 sont des vues simplifiées et similaires à la figure 1 du dispositif suivant l'invention, dans les positions de travail et effacée du levier à pivot mobile, respectivement.Figures 3 and 4 are simplified views similar to Figure 1 of the device according to the invention, in the working positions and cleared from the movable pivot lever, respectively.

La figure 5 est une vue en coupe verticale et suivant la ligne V-V de la figure 1.FIG. 5 is a view in vertical section and along the line V-V of FIG. 1.

La figure 6 est une vue en plan et suivant la flèche VI-VI de la figure 5 des leviers à pivot fixe et à pivot mobile du dispositif visible sur les figures 1 à 5.FIG. 6 is a plan view and along arrow VI-VI of FIG. 5 of the levers with fixed pivot and with movable pivot of the device visible in FIGS. 1 to 5.

La figure 7 est une vue similaire à la figure 1 illustrant un deuxième mode de réalisation de l'invention.Figure 7 is a view similar to Figure 1 illustrating a second embodiment of the invention.

Les figures 8 et 9 sont des vues similaires aux figures 3 et 4 respectivement, et qui représentent le dispositif visible sur la figure 7.FIGS. 8 and 9 are views similar to FIGS. 3 and 4 respectively, and which represent the device visible in FIG. 7.

La figure 10 est une vue similaire à la figure 5 et illustrant les leviers à pivots fixe et à pivot mobile visibles sur les figures 7 à 9.FIG. 10 is a view similar to FIG. 5 and illustrating the levers with fixed pivots and with movable pivot visible in FIGS. 7 to 9.

La figure 11 est une vue en plan et suivant la flèche XI de la figure 10, des leviers à pivots fixes et à pivot mobile du deuxième mode de réalisation du dispositif conforme à l'invention.Figure 11 is a plan view and along arrow XI of Figure 10, levers with fixed pivots and movable pivot of the second embodiment of the device according to the invention.

La figure 12 est une vue en coupe et suivant un plan vertical coupant l'axe longitudinal de l'arbre de sélection d'un dispositif suivant un troisième mode de réalisation de l'invention.Figure 12 is a sectional view along a vertical plane intersecting the longitudinal axis of the selection shaft of a device according to a third embodiment of the invention.

La figure 13 est une vue en coupe verticale et suivant la ligne XIII-XIII de la figure 12.FIG. 13 is a view in vertical section and along the line XIII-XIII of FIG. 12.

Les figures 14 et 15 sont des vues similaires à la figure 13 et dans lesquelles le levier à pivot mobile est en position de travail et en position effacée, respectivement.Figures 14 and 15 are views similar to Figure 13 and in which the movable pivot lever is in the working position and in the retracted position, respectively.

La figure 16 est une vue en coupe verticale et suivant la ligne XVI-XVI de la figure 13.FIG. 16 is a view in vertical section and along the line XVI-XVI of FIG. 13.

La figure 17 est une vue en plan et suivant la flèche XVII de la figure 16, qui illustre les leviers à pivot fixe et à pivot mobile du troisième mode de réalisation de l'invention.Figure 17 is a plan view and along arrow XVII of Figure 16, which illustrates the fixed pivot and movable pivot levers of the third embodiment of the invention.

La figure 18 est une vue schématique et illustrant un système de contrôle du dispositif conforme à l'invention.Figure 18 is a schematic view illustrating a device control system according to the invention.

En se reportant aux figures 1 à 6, un premier mode de réalisation de la présente invention va maintenant être décrit. On voit sur les figures 1 et 2 une partie de la culasse 1 d'un moteur à combustion interne de type quelconque, dans laquelle partie une soupape 2 est montée coulissante suivant l'axe longitudinal de sa tige 2a. La partie inférieure de la tige de soupape 2a est guidée dans un canon 3, et sa partie supérieure présente une gorge 2b, sur laquelle est fixée une coupelle 4. Une deuxième coupelle 5 est montée autour d'une partie du canon 3 qui fait saillie de la culasse 1, de façon à recevoir de façon coaxiale à la tige 2a un ressort de rappel 6 qui exerce sur la soupape 2 un effort ayant tendance à éloigner la coupelle 4 de la coupelle 5. Comme on le voit bien sur la figure 5, le dispositif de levée à amplitude variable suivant l'invention permet d'agir sur deux soupapes repérées en 2 et qui sont équipées chacune de coupelles 4 et 5, ainsi que de ressorts de rappel 6.Referring to Figures 1 to 6, a first embodiment of the present invention will now be described. FIGS. 1 and 2 show a part of the cylinder head 1 of an internal combustion engine of any type, in which part a valve 2 is slidably mounted along the longitudinal axis of its rod 2a. The lower part of the valve stem 2a is guided in a barrel 3, and its upper part has a groove 2b, on which is fixed a cup 4. A second cup 5 is mounted around a part of the barrel 3 which projects of the cylinder head 1, so as to receive coaxially with the rod 2a a return spring 6 which exerts on the valve 2 a force tending to move the cup 4 away from the cup 5. As can be seen in FIG. 5 , the lifting device with variable amplitude according to the invention makes it possible to act on two valves marked at 2 and which are each equipped with cups 4 and 5, as well as return springs 6.

Sur les figures 1 à 4, la référence numérique 7 désigne un arbre de commande entraîné en rotation, duquel sont solidaires trois cames excentriques et désignées par les références H et B. Deux cames B ayant des profils bas identiques sont disposées sur l'arbre 7, de part et d'autre d'une came H qui présente un profil haut, c'est-à-dire dont le profil du chemin de guidage comme visible par exemple sur la figure 1, est plus fortement en saillie de l'arbre 7, comparé aux cames basses B. Deux leviers en forme de linguets et généralement désignés par les références F et M s'étendent au droit des cames B et H, respectivement. En se reportant aux figures 5 et 6, on voit que le linguet F a sensiblement la forme d'un O avec deux branches parallèles 8 et 9 qui s'étendent suivant la direction longitudinale du linguet F. Les branches parallèles 8 et 9 du linguet F sont raccordées l'une à l'autre par leurs extrémités d'un côté par une partie transversale 10 qui s'étend sensiblement parallèlement à l'axe de rotation de l'arbre 7, et de l'autre côté par une partie coudée 11. On a illustré en pointillés sur les figures 6 et 7 un levier droit ou linguet M qui s'étend suivant une direction parallèle aux branches 8 et 9, et qui est disposé entre deux surfaces de guidage 22 et 23 des branches 8 et 9, respectivement. Le linguet M comporte à son extrémité libre un doigt de contact 12 sur la face inférieure duquel est formé une surface d'appui S qui s'étend au droit de la partie transversale 10 du levier F.In FIGS. 1 to 4, the reference numeral 7 designates a control shaft driven in rotation, of which three eccentric cams are integral and designated by the references H and B. Two cams B having identical low profiles are arranged on the shaft 7 , on either side of a cam H which has a high profile, that is to say the profile of the guide path as visible for example in Figure 1, is more strongly projecting from the shaft 7, compared to the low cams B. Two levers in the form of latches and generally designated by the references F and M extend to the right of the cams B and H, respectively. Referring to Figures 5 and 6, we see that the latch F has substantially the shape of an O with two parallel branches 8 and 9 which extend in the longitudinal direction of the latch F. The parallel branches 8 and 9 of the latch F are connected to each other by their ends on one side by a transverse part 10 which extends substantially parallel to the axis of rotation of the shaft 7, and on the other side by a bent part 11. A dotted lever in FIGS. 6 and 7 illustrates a straight lever or latch M which extends in a direction parallel to the branches 8 and 9, and which is arranged between two guide surfaces 22 and 23 of the branches 8 and 9 , respectively. The latch M has at its free end a contact finger 12 on the underside of which is formed a support surface S which extends in line with the transverse part 10 of the lever F.

Deux patins 18 et 19 à la face inférieure de la partie transversale 10, forment respectivement une surface de contact avec une extrémité de l'une des deux soupapes 2, et s'étendent dans le prolongement des branches 8 et 9 respectivement, et symétriquement de part et d'autre du doigt de contact 12, comme visible sur les figures 5 et 6. A l'extrémité des linguets F et M qui est opposée aux soupapes 2, sont formées des portées sphériques 8a, 9a et Ma, respectivement dans les branches 8, 9 et dans le linguet M, des pivots 13, 14 et 15 étant respectivement logés dans ces portées. Ces pivots 13, 14 et 15 permettent l'articulation par liaison rotulante des linguets F et M par rapport à la culasse 1.Two pads 18 and 19 on the underside of the transverse part 10, respectively form a contact surface with one end of one of the two valves 2, and extend in the extension of the branches 8 and 9 respectively, and symmetrically of on either side of the contact finger 12, as visible in FIGS. 5 and 6. At the end of the latches F and M which is opposite to the valves 2, spherical bearings 8a, 9a and Ma are formed, respectively in the branches 8, 9 and in the latch M, pivots 13, 14 and 15 being respectively housed in these bearing surfaces. These pivots 13, 14 and 15 allow the articulation by swiveling connection of the latches F and M relative to the cylinder head 1.

On voit bien sur la figure 2 que les pivots 13 et 14 sont directement vissés dans la culasse 1 et sont verrouillés par des contre-écrous 16 et 17 respectivement, dont la face inférieure repose contre la culasse 1. La hauteur de saillie des pivots 13 et 14 est ajustée avant serrage des contre-écrous 16 et 17 de façon que des surfaces convexes 20 et 21 des branches parallèles 8 et 9 du levier F viennent sensiblement en contact, au jeu de fonctionnement près, avec la partie circulaire dite dos de l'une des cames basses B respectivement quand la soupape 2 associée est fermée par son ressort 6, la tige 2a saillant au maximum de la culasse. Il convient de noter ici que, pour assurer le réglage automatique du jeu de fonctionnement aux soupapes 2, il est possible de remplacer les pivots fixes visibles sur les figures et repérés en 13 et 14 par des compensateurs hydrauliques (non représentés).It can be seen in FIG. 2 that the pivots 13 and 14 are directly screwed into the cylinder head 1 and are locked by lock nuts 16 and 17 respectively, the lower face of which rests against the cylinder head 1. The height of the projection of the pivots 13 and 14 is adjusted before tightening the locknuts 16 and 17 so that the convex surfaces 20 and 21 of the parallel arms 8 and 9 of the lever F come substantially into contact, apart from the operating clearance, with the circular part called the back of the 'one of the low cams B respectively when the associated valve 2 is closed by its spring 6, the rod 2a projecting as far as possible from the cylinder head. It should be noted here that, to ensure the automatic adjustment of the operating clearance at the valves 2, it is possible to replace the fixed pivots visible in the figures and identified at 13 and 14 by hydraulic compensators (not shown).

Sur les figures 1 et 2, la référence numérique 24 désigne un guide de forme cylindrique, qui est monté coulissant dans un alésage la de la culasse et dans lequel est vissé le pivot 15, à l'aide d'un contre-écrou 26. L'alésage la débouche dans un logement 1b de la culasse, qui s'étend sensiblement parallèlement à l'axe de rotation de l'arbre de commande 7. Un arbre 25 est monté pivotant dans ce logement 1b et comporte, au regard de l'alésage la, une came de sélection 27 de la position active ou escamotée de l'ensemble guide 24 - pivot 15. Quelle que soit la position de cet ensemble, la face inférieure du guide 24 repose contre la périphérie de la came de sélection 27. Sous l'effet du ressort de rappel 6 qui transmet au levier M un effort de direction confondue avec l'axe longitudinal de la soupape 2, une surface d'appui 35 de ce levier tend à être plaquée contre la came H.In FIGS. 1 and 2, the reference numeral 24 designates a cylindrical guide, which is slidably mounted in a bore 1a of the cylinder head and into which the pivot 15 is screwed, using a lock nut 26. The bore opens into a housing 1b of the cylinder head, which extends substantially parallel to the axis of rotation of the control shaft 7. A shaft 25 is pivotally mounted in this housing 1b and comprises, with regard to the the bore 1a, a selection cam 27 of the active or retracted position of the guide assembly 24 - pivot 15. Whatever the position of this assembly, the underside of the guide 24 rests against the periphery of the selection cam 27 Under the effect of the return spring 6 which transmits to the lever M a steering force coincident with the longitudinal axis of the valve 2, a bearing surface 35 of this lever tends to be pressed against the cam H.

On précisera ici que dans le cas où l'arbre de sélection 25 s'étend sensiblement parallèlement à l'arbre de commande, un arbre de sélection unique peut comporter plusieurs cames de sélection, situées à des intervalles correspondants à l'emplacement d'autres dispositifs de levée de soupape d'un même moteur. Avec un tel arbre de sélection unique pour plusieurs dispositifs, la synchronisation du changement d'amplitude de la levée de soupape de plusieurs cylindres d'un moteur est simplifiée. L'arbre de sélection peut être par exemple relié à un moteur pas-à-pas (non représenté) ou à un mécanisme de transmission tel qu'un engrenage ou une courroie synchrone (non représentés), et qui est raccordé à l'arbre de commande par l'intermédiaire d'un embrayage électromagnétique. Dans ces deux cas, il est avantageux que l'entraînement de l'arbre de sélection soit effectué par un mécanisme permettant qu'à un tour de l'arbre de commande corresponde un demi-tour de l'arbre de sélection, de façon que le changement d'amplitude de la levée des soupapes s'effectue, comme expliqué ci-après, sur un demi-tour de l'arbre de sélection et de façon que le premier pivot actionné par l'arbre a déjà changé d'état (actif-escamoté) lorsque l'on commence à faire changer l'état du dernier pivot actionné par le même arbre de sélection.It will be specified here that in the case where the selection shaft 25 extends substantially parallel to the control shaft, a single selection shaft may comprise several selection cams, located at intervals corresponding to the location of other valve lift devices of the same engine. With such a single selection shaft for several devices, the synchronization of the change in amplitude of the valve lift of several cylinders of an engine is simplified. The selection shaft can for example be connected to a stepping motor (not shown) or to a transmission mechanism such as a gear or a synchronous belt (not shown), and which is connected to the shaft control via an electromagnetic clutch. In these two cases, it is advantageous that the drive of the drive shaft selection is carried out by a mechanism allowing a revolution of the control shaft to correspond to a half-revolution of the selection shaft, so that the amplitude change of the valve lift takes place, as explained below -after, on a half-turn of the selection shaft and so that the first pivot actuated by the shaft has already changed state (active-retracted) when we start to change the state of the last pivot operated by the same selection shaft.

Il convient également de noter ici que, suivant les cas, l'entraînement de l'arbre de sélection, c'est-à-dire la variation de l'amplitude de la levée de soupape, pourra être déclenché manuellement, mécaniquement ou électroniquement, en fonction de paramètres du fonctionnement du moteur. On a illustré sur la figure 18, un exemple de système de contrôle électronique du changement d'amplitude de la levée des soupapes 2. Ce système de déclenchement est principalement constitué par un boîtier 30 qui est d'une part connecté à un mécanisme d'entraînement (non représenté) de l'arbre de sélection, de façon à lui fournir des signaux de contrôle, en fonction de signaux d'état du fonctionnement du moteur, qui proviennent de capteurs auxquels le boîtier 30 est d'autre part connecté. On a par exemple repéré en 28 un capteur sensible à la vitesse de rotation d'un vilebrequin 29, en 31 un capteur permettant de déterminer la position du "dos" des cames de commande B et H, par repérage de la position angulaire d'une roue de commande 33 des cames B et H, et en 32 un capteur sensible à l'angle d'ouverture de la vanne papillon de l'admission du moteur, les capteurs 28, 31 et 32 fournissant au boitier 30 des paramètres qui lui permettent de décider de l'opportunité d'une variation d'amplitude de la levée des soupapes, par exemple à l'aide d'un programme stocké dans une mémoire morte.It should also be noted here that, depending on the case, the drive of the selection shaft, that is to say the variation of the amplitude of the valve lift, may be triggered manually, mechanically or electronically, depending on engine operating parameters. Illustrated in FIG. 18 is an example of an electronic control system for the change in amplitude of the valve lift 2. This trigger system mainly consists of a housing 30 which is firstly connected to a mechanism for drive (not shown) of the selection shaft, so as to provide it with control signals, as a function of engine operating status signals, which come from sensors to which the housing 30 is also connected. We have for example identified at 28 a sensor sensitive to the speed of rotation of a crankshaft 29, at 31 a sensor making it possible to determine the position of the "back" of the control cams B and H, by locating the angular position of a control wheel 33 of the cams B and H, and at 32 a sensor sensitive to the opening angle of the butterfly valve of the engine intake, the sensors 28, 31 and 32 supplying the housing 30 with parameters which allow to decide on the advisability of a variation in amplitude of valve lift, for example using a program stored in a read-only memory.

En se reportant maintenant aux figures 3 et 4, le fonctionnement du mode de réalisation décrit plus haut va être expliqué.Referring now to Figures 3 and 4, the operation of the embodiment described above will be explained.

La figure 3 représente le dispositif dans une position active du pivot mobile 15 autour duquel est articulé le levier M. Dans cette position active, la came de sélection 27 de l'arbre 25 est orientée de façon que la partie la plus excentrée de cette came soit en contact avec la face inférieure du guide 24, pour que l'ensemble guide 24 - pivot 15 soit fortement en saillie de la face supérieure de la culasse 1 où débouche l'alésage 1A. Avec le pivot 15 en position active, le linguet M est en position de travail, c'est-à-dire est en contact par sa surface convexe 35 avec la came de commande H, sous l'effet de la force exercée par le ressort 6 (non représenté sur les figures 3 et 4), qui agit sur les soupapes 2 et sur la partie transversale 10 du levier F faisant office d'intermédiaire entre le ressort et la surface d'appui S du doigt de contact 12. On voit bien sur la figure 3 que lorsque le levier M est en position de travail, le levier F est éloigné des cames de commande B, sous l'effet du doigt de contact 12 du levier M, ce qui correspond à la position effacée du levier F. Ces positions effacée du levier F et active du levier M permettent la coopération de la came de commande H qui possède un profil "haut" avec le levier M, et permet ainsi d'obtenir par l'intermédiaire de la partie transversale 10 du linguet F une amplitude importante de la levée de soupape.FIG. 3 shows the device in an active position of the movable pivot 15 around which the lever M is articulated. In this active position, the selection cam 27 of the shaft 25 is oriented so that the most eccentric part of this cam either in contact with the lower face of the guide 24, so that the guide 24 - pivot 15 assembly is strongly projecting from the upper face of the cylinder head 1 where the bore 1A opens. With the pivot 15 in the active position, the latch M is in the working position, that is to say is in contact by its convex surface 35 with the control cam H, under the effect of the force exerted by the spring. 6 (not shown in FIGS. 3 and 4), which acts on the valves 2 and on the transverse part 10 of the lever F acting as an intermediary between the spring and the bearing surface S of the contact finger 12. We see indeed in FIG. 3 that when the lever M is in the working position, the lever F is distant from the control cams B, under the effect of the contact finger 12 of the lever M, which corresponds to the erased position of the lever F These positions erased from the lever F and active from the lever M allow the cooperation of the control cam H which has a "high" profile with the lever M, and thus makes it possible to obtain via the transverse part 10 of the latch F a large amplitude of the valve lift.

Dans le cas où par exemple, l'un des capteurs 28 et 32 fournit au boîtier 30 un signal correspondant à des paramètres de fonctionnement du moteur suivant lesquels il est préférable de limiter l'amplitude de la levée des soupapes 2 pour améliorer le fonctionnement du moteur, alors le boîtier 30 va délivrer un signal de déclenchement du mécanisme d'entraînement de l'arbre de sélection 25, de façon que celui-ci pivote jusqu'à la position angulaire visible sur la figure 4.In the case where, for example, one of the sensors 28 and 32 provides the housing 30 with a signal corresponding to engine operating parameters according to which it is preferable to limit the amplitude of the lifting of the valves 2 to improve the operation of the motor, then the housing 30 will deliver a trigger signal of the drive mechanism of the selection shaft 25, so that the latter pivots to the angular position visible in FIG. 4.

On précisera ici que le changement d'amplitude de la levée de soupape n'est effectué, grâce au signal du capteur 31, que lorsque le dos - c'est-à-dire la partie de rayon constant et bas- des cames de commande B et H sont au regard des surfaces convexes 20, 21 et 35 des leviers F et M, ce qui correspond à un état "fermé" des soupapes 2.It will be specified here that the change in amplitude of the valve lift is effected, thanks to the signal from the sensor 31, only when the back - that is to say the part of constant and low radius - of the control cams B and H are facing the convex surfaces 20, 21 and 35 of the levers F and M, which corresponds to a "closed" state of the valves 2.

Dans la position illustrée sur la figure 4 et qui correspond à une levée de soupape d'amplitude réduite en comparaison avec celle décrite précédemment, la face inférieure du guide 24 est en contact avec le dos de la came 27. L'ensemble guide coulissant 24 - pivot 15 est alors escamoté dans le logement 1b de la culasse 1. Avec le pivot 15 en position escamotée, le linguet M vient en position effacée, et le linguet F peut alors coopérer avec les cames basses B contre lesquelles les surfaces 20 et 21 sont plaquées sous l'effet de la force du ressort de rappel 6 (non représenté sur cette figure), et grâce au "déverrouillage" du pivot 15 qui permet au levier M "de s'adapter" à l'action de la came de commande H par l'articulation et le glissement des deux linguets M et F l'un sur l'autre.In the position illustrated in FIG. 4 and which corresponds to a valve lift of reduced amplitude in comparison with that described above, the underside of the guide 24 is in contact with the back of the cam 27. The sliding guide assembly 24 - pivot 15 is then retracted into the housing 1b of the cylinder head 1. With the pivot 15 in the retracted position, the latch M comes into the retracted position, and the latch F can then cooperate with the low cams B against which the surfaces 20 and 21 are pressed under the effect of the force of the return spring 6 (not shown in this figure), and thanks to the "unlocking" of the pivot 15 which allows the lever M "to adapt" to the action of the cam control H by the articulation and the sliding of the two latches M and F one on the other.

On comprend donc que puisque les leviers sont reliés aux soupapes 2 de façon que seul le levier F à pivot fixe est en contact direct avec les soupapes 2, le levier à pivot fixe est susceptible de venir en contact contre la surface d'appui du levier M pour qu'en position de travail du levier à pivot fixe, celui-ci soit en appui contre ladite surface S du levier mobile dans sa position effacée, et que lorsque le levier à pivot mobile est en position effacée, le déplacement du pivot 15 est tel qu'il permet au levier M d'être écarté de la came H associée quand l'arbre 7 tourne, et au levier F à pivot fixe de venir en contact avec la came B correspondante sous l'effet des ressorts de rappel 6 des soupapes.It is therefore understood that since the levers are connected to the valves 2 so that only the lever F with fixed pivot is in direct contact with the valves 2, the lever with fixed pivot is capable of coming into contact against the bearing surface of the lever M so that in the working position of the fixed pivot lever, the latter is in abutment against said surface S of the movable lever in its retracted position, and that when the movable pivot lever is in the retracted position, the displacement of the pivot 15 is such that it allows the lever M to be moved away from the associated cam H when the shaft 7 rotates, and to the lever F with fixed pivot to come into contact with the corresponding cam B under the effect of the return springs 6 valves.

Le dispositif suivant l'invention tire avantageusement parti de la liaison par simple appui des leviers M et F entre eux pour permettre une "adaptation" du levier F en position de travail sous l'effet du ressort 6 afin que le levier F coopère avec les cames B à profil bas.The device according to the invention advantageously takes advantage of the connection by simply pressing the levers M and F together to allow an "adaptation" of the lever F in the working position under the effect of the spring 6 so that the lever F cooperates with the low profile B cams.

On a ainsi obtenu un dispositif de levée de soupape à amplitude variable dans lequel chaque levier est susceptible d'un mouvement entre une position de travail en contact avec la came de commande et une position effacée, de façon que les leviers agissent alternativement et sélectivement sur les soupapes en fonction de paramètres de fonctionnement du moteur. En effet, grâce au mouvement relatif de la partie transversale 10 du levier F et du doigt de contact 12 du levier M, l'un des linguets est en position effacée lorsque l'autre est en position de travail, sans pour autant que les deux linguets soient articulés par l'intermédiaire de pivots coulissant dans la culasse 1.There was thus obtained a valve lift device with variable amplitude in which each lever is capable of movement between a working position in contact with the control cam and a cleared position, so that the levers act alternately and selectively on the valves according to engine operating parameters. Indeed, thanks to the relative movement of the transverse part 10 of the lever F and the contact finger 12 of the lever M, one of the latches is in the retracted position when the other is in the working position, without the two catches being articulated by means of pivots sliding in the cylinder head 1.

En se reportant maintenant aux figures 7 à 11, un deuxième mode de réalisation de la présente invention va être décrit. Sur ces figures, les pièces et éléments similaires ou identiques à ceux décrits et illustrés plus haut seront désignés par les mêmes références numériques, et leur description ne sera donc pas nécessaire.Referring now to Figures 7 to 11, a second embodiment of the present invention will be described. In these figures, parts and elements similar or identical to those described and illustrated above will be designated by the same reference numerals, and their description will therefore not be necessary.

Ce mode de réalisation de l'invention se distingue principalement du premier par le fait qu'au droit de chaque came basse B de l'arbre 7 sont disposés des leviers droits 8 et 9. Ces leviers présentent la forme de linguets et sont articulés par rapport à la culasse 1 à l'aide des pivots fixes 13 et 14, respectivement. Chaque linguet 8, 9 comporte à son extrémité opposée à sa liaison rotulante, un doigt de contact dont l'un est repéré en 38 et l'autre en 39. De plus, chacun de ces linguets 8 et 9 comporte à sa partie supérieure une surface convexe 20, 21, apte à coopérer par contact avec l'une des cames basses B.This embodiment of the invention differs mainly from the first by the fact that at the right of each low cam B of the shaft 7 are arranged straight levers 8 and 9. These levers have the form of latches and are articulated by relative to the cylinder head 1 using the fixed pivots 13 and 14, respectively. Each latch 8, 9 has at its end opposite its swiveling connection, a contact finger, one of which is marked at 38 and the other at 39. In addition, each of these lugs 8 and 9 has at its upper part a convex surface 20, 21, able to cooperate by contact with one of the low cams B.

Au droit de la came haute H, est prévu un levier M présentant la forme d'un T, avec une surface convexe 35 apte à coopérer par contact avec la came H. La branche longitudinale du levier M qui constitue la barre verticale du T est articulée sur un ensemble pivot 15 - guide 24, qui coulisse dans la culasse 1. Une partie transversale 10 du levier M s'étend sensiblement parallèlement à l'axe de rotation des arbres 7 et 25, jusqu'au droit des doigts de contact 38 et 39 des linguets droits 8 et 9. Chaque extrémité de la partie transversale 10 comporte à sa partie inférieure un patin convexe 18, 19, formant surface de contact pour que chaque extrémité de cette partie 10 du levier M repose sur l'une des soupapes 2. On voit bien sur la figure 10 que la barre transversale 10 comporte à sa partie supérieure et au droit des patins de contact 18 et 19 des surfaces d'appui S. Sur la figure 11, on voit que la partie longitudinale du levier M s'étend entre deux faces de guidage 22 et 23 des leviers droits 8 et 9, respectivement, tandis que les doigts de contact 38 et 39 sont quant à eux positionnés latéralement par des rebords 37 qui font saillie de la face supérieure de la partie transversale 10 du levier M, depuis un bord extérieur de chacune des surfaces d'appui S, ce qui permet le positionnement latéral de l'ensemble des trois leviers.To the right of the high cam H, there is provided a lever M having the shape of a T, with a convex surface 35 able to cooperate by contact with the cam H. The longitudinal branch of the lever M which constitutes the vertical bar of the T is articulated on a pivot 15 - guide 24 assembly, which slides in the cylinder head 1. A transverse part 10 of the lever M extends substantially parallel to the axis of rotation of the shafts 7 and 25, to the right of the contact fingers 38 and 39 straight latches 8 and 9. Each end of the transverse part 10 has at its part lower a convex pad 18, 19, forming a contact surface so that each end of this part 10 of the lever M rests on one of the valves 2. It can be seen in FIG. 10 that the crossbar 10 has at its upper part and in line with the contact pads 18 and 19 of the bearing surfaces S. In FIG. 11, it can be seen that the longitudinal part of the lever M extends between two guide faces 22 and 23 of the straight levers 8 and 9, respectively, while the contact fingers 38 and 39 are in turn positioned laterally by flanges 37 which project from the upper face of the transverse part 10 of the lever M, from an outer edge of each of the bearing surfaces S, which allows lateral positioning of all three levers.

La référence numérique 48 désigne un organe élastique qui est constitué par une lame métallique et élastiquement déformable. Bien qu'un seul de ces organes soit représenté, le dispositif visible sur les figures 7 à 11 comporte deux de ces organes 48, dont l'extrémité libre de chacun vient en appui contre la face inférieure de l'un des linguets 8 ou 9, de façon à exercer sur celui-ci une force ayant tendance à le plaquer contre la came B correspondante. L'autre extrémité de chacun de ces organes 48 est fixée à la culasse 1 à l'aide de l'un des contre-écrous 16 et 17 qui est vissé sur l'un des pivots fixes 13, 14.The reference numeral 48 designates an elastic member which is constituted by a metal blade and elastically deformable. Although only one of these members is shown, the device visible in FIGS. 7 to 11 comprises two of these members 48, the free end of each of which bears against the underside of one of the lugs 8 or 9 , so as to exert on it a force tending to press it against the corresponding cam B. The other end of each of these members 48 is fixed to the cylinder head 1 by means of one of the locknuts 16 and 17 which is screwed onto one of the fixed pivots 13, 14.

Nous allons maintenant brièvement expliquer le fonctionnement du mode de réalisation de l'invention décrit ci-dessus.We will now briefly explain the operation of the embodiment of the invention described above.

La figure 8 illustre le dispositif conforme à l'invention avec le levier M en position de travail, sous l'effet d'une part du pivot mobile 15 qui est placé en position active par la came de sélection 27, et d'autre part sous l'effet de la came haute H qui est en contact avec la surface convexe 35. Grâce à la force exercée par les ressorts de rappel 6 (non représentés), les soupapes 2 viennent en appui contre les surfaces de contact 18 et 19 de la partie transversale 10 du levier M. Dans la position illustrée sur la figure 8, on obtient une amplitude importante de la levée des soupapes 2 qui sont directement déplacées par les patins convexes 18 et 19 du levier M. Dans cette position de travail du levier M, les linguets 8 et 9 sont respectivement plaqués en position effacée contre l'une des cames B, sous l'effet des organes élastiques 48 et de façon qu'un espace "e" se forme entre la face inférieure de chaque doigt de contact 38 et 39 et la surface d'appui S du levier M. Cet espace "e" permet d'éviter que les linguets 8 et 9 portent sur la partie transversale 10 du levier M et en conséquence, appliquent un poids mort sur les soupapes 2, ce qui permet d'améliorer les réactions dynamiques des ressorts de rappel 6 des soupapes 2, à haut régime du moteur.FIG. 8 illustrates the device according to the invention with the lever M in the working position, under the effect on the one hand of the movable pivot 15 which is placed in the active position by the selection cam 27, and on the other hand under the effect of the high cam H which is in contact with the convex surface 35. Thanks to the force exerted by the return springs 6 (not shown), the valves 2 come to bear against the contact surfaces 18 and 19 of the transverse part 10 of the lever M. In the position illustrated in FIG. 8, a large amplitude is obtained from the lifting of the valves 2 which are directly displaced by the convex pads 18 and 19 of the lever M. In this working position of the lever M, the latches 8 and 9 are respectively pressed in the erased position against one of the cams B, under the effect of the elastic members 48 and so that a space "e" is formed between the underside of each contact finger 38 and 39 and the bearing surface S of the lever M. This space "e" makes it possible to prevent the latches 8 and 9 from bearing on the transverse part 10 of the lever M and consequently apply a dead weight to the valves 2, which makes it possible to improve the dynamic reactions of the return springs 6 of valves 2, at high engine speed.

Comme pour le mode de réalisation précédent, le changement d'amplitude de la levée des soupapes 2 est effectué grâce à la rotation de l'arbre 25, et lorsque les cames de commande B et H présentent leurs dos face aux surfaces 20, 21 et 35. Cette rotation place le dispositif dans l'état visible sur la figure 9.As for the previous embodiment, the change in amplitude of the lifting of the valves 2 is effected by the rotation of the shaft 25, and when the control cams B and H have their backs facing the surfaces 20, 21 and 35. This rotation places the device in the state visible in FIG. 9.

La figure 9 représente donc le dispositif avec le levier M dans sa position effacée, c'est-à-dire avec le dos de la came de sélection 27 au regard du guide coulissant 24. Les doigts de contact 38 et 39 des linguets 8 et 9 sont quant à eux plaqués sous l'effet des cames B, contre les surfaces d'appui S de la partie transversale 10 du levier M, afin que ce dernier transmette le mouvement des linguets 8 et 9 aux soupapes 2. Comme pour le mode de réalisation prédédent, lors du "déverrouillage" du pivot 15, en position escamotée, le levier M est écarté de la came H quand l'arbre 7 tourne, donc est sans action sur les tiges des soupapes 2. Cette position dans laquelle le levier M à pivot mobile est effacé et où les leviers 8 et 9 sont en appui contre les surfaces S du levier M, permet d'obtenir une amplitude limitée de la levée des soupapes, en comparaison avec l'amplitude obtenue dans l'état du dispositif visible sur la figure 8. On rappellera ici qu'il convient que le coulissement du pivot mobile 15 soit tel qu'il permette aux leviers 8 et 9 qui sont montés sur des pivots fixes 13 et 14, de venir en contact avec les cames B correspondantes, sous l'effet des ressorts de rappel 6 de chaque soupape 2.FIG. 9 therefore represents the device with the lever M in its erased position, that is to say with the back of the selection cam 27 facing the sliding guide 24. The contact fingers 38 and 39 of the latches 8 and 9 are pressed against the effect of the cams B, against the bearing surfaces S of the transverse part 10 of the lever M, so that the latter transmits the movement of the latches 8 and 9 to the valves 2. As for the mode previous embodiment, during the "unlocking" of the pivot 15, in the retracted position, the lever M is moved away from the cam H when the shaft 7 rotates, therefore has no action on the valve stems 2. This position in which the lever M with movable pivot is erased and where the levers 8 and 9 are pressed against the surfaces S of the lever M, makes it possible to obtain a limited amplitude of the lifting of the valves, in comparison with the amplitude obtained in the state of the device visible in Figure 8. It will be recalled here that the co ulissement of the movable pivot 15 is such that it allows the levers 8 and 9 which are mounted on fixed pivots 13 and 14, to come into contact with the corresponding cams B, under the effect of the return springs 6 of each valve 2 .

On a représenté sur les figures 12 à 17 un troisième mode de réalisation de l'invention, pour lequel les mêmes références numériques que celles des modes de réalisation précédents désignent des pièces ou éléments similaires ou identiques, et qui n'auront par conséquent pas besoin d'être décrits à nouveau.FIGS. 12 to 17 show a third embodiment of the invention, for which the same reference numbers as those of the preceding embodiments designate similar or identical parts or elements, and which consequently will not need to be described again.

Suivant ce mode de réalisation, l'arbre de commande 7 comporte une seule came B à profil bas et deux cames H à profil haut qui sont disposées de part et d'autre de la came B. Chaque came H coopère avec l'un de deux leviers droits ou linguets 58 et 59 qui sont articulés sur la culasse 1 par l'intermédiaire de pivots mobiles 15. Ces pivots 15 sont fixés à des guides 24 qui coulissent chacun dans un alésage la de la culasse 1 et qui débouchent au droit d'un arbre 25 qui est monté pivotant et sur lequel sont formées deux cames 27 de sélection entre une position escamotée et une position active des deux ensembles guide 24 - pivot 15.According to this embodiment, the control shaft 7 comprises a single low profile cam B and two high profile cams H which are arranged on either side of the cam B. Each cam H cooperates with one of of them straight levers or latches 58 and 59 which are articulated on the cylinder head 1 by means of mobile pivots 15. These pivots 15 are fixed to guides 24 which each slide in a bore 1a of the cylinder head 1 and which open at right angle a shaft 25 which is pivotally mounted and on which two cams 27 for selecting between a retracted position and an active position of the two guide 24 - pivot 15 assemblies are formed.

A l'extrémité opposée au pivot 15, chacun des linguets 58 et 59 possède un doigt de contact 38 et 39, respectivement. Les doigts de contact 38 et 39 présentent à leur partie inférieure des patins convexes 18 et 19 respectivement, qui permettent le contact des soupapes 2 avec les linguets 58 et 59, tout en autorisant leur déplacement par glissement lors des changements d'amplitude de la levée. A la partie supérieure de chaque doigt de contact 38, 39, s'étend une surface d'appui S, apte à coopérer avec un levier F à pivot fixe par rapport à la culasse 1. En se reportant aux figures 16 et 17, on voit que le levier F présente la forme d'un T et s'étend entre deux surfaces de guidage 22 et 23 des linguets 58 et 59 respectivement, ces surfaces étant situées au regard l'une de l'autre et permettant de guider latéralement le linguet F. Comme on vient de le dire, le levier F est monté sur la culasse 1 à l'aide d'un pivot fixe 13 et d'un contre-écrou 16. Une partie transversale 10 du levier F s'étend sensiblement suivant une direction parallèle à l'axe de rotation des arbres 7 et 25, avec chacune de ses extrémités venant jusqu'au droit de l'un des doigts de contact 38 ou 39. On a repéré en 48 un organe élastique unique qui est constitué par une lame métallique fixée à la culasse 1 à l'aide du pivot 13 et du contre-écrou 16, alors que son extrémité libre vient en contact avec la face inférieure de la partie longitudinale du levier T, de façon à exercer sur ce levier une force ayant tendance à plaquer ce dernier contre la came B correspondante.At the end opposite the pivot 15, each of the latches 58 and 59 has a contact finger 38 and 39, respectively. The contact fingers 38 and 39 have at their lower part convex pads 18 and 19 respectively, which allow the contact of the valves 2 with the latches 58 and 59, while allowing their displacement by sliding during changes in amplitude of the lift . At the upper part of each contact finger 38, 39, extends a bearing surface S, able to cooperate with a lever F with a pivot pivoted relative to the cylinder head 1. Referring to Figures 16 and 17, we sees that the lever F has the shape of a T and extends between two guide surfaces 22 and 23 of the latches 58 and 59 respectively, these surfaces being located facing each other and making it possible to guide the side latch F. As we have just said, the lever F is mounted on the cylinder head 1 by means of a fixed pivot 13 and a lock nut 16. A transverse part 10 of the lever F extends substantially along a direction parallel to the axis of rotation of the shafts 7 and 25, with each of its ends coming to the right of one of the contact fingers 38 or 39. A single elastic member has been located at 48 which is constituted by a metal blade fixed to the cylinder head 1 using the pivot 13 and the lock nut 16, while its free end comes into contact with the underside of the longitudinal part of the lever T, so as to exert on this lever a force tending to press the latter against the corresponding cam B.

Le fonctionnement du dispositif décrit ci-dessus est similaire à celui des modes de réalisation précédents et permet d'obtenir une levée de soupape à amplitude importante à l'aide des cames hautes H qui actionnent directement les linguets 58 et 59 qui sont en appui contre les tiges 2a des soupapes 2. Comme visible sur la figure 14, en position de travail des leviers mobiles 58 et 59 et effacée du levier fixe F, le levier F en forme de T est maintenu en contact avec la came B sous l'effet de la force appliquée par l'organe élastique 48, ce qui permet la formation d'un espace "e" grâce auquel la partie 10 du levier F est éloignée des doigts 38, 39 des linguets 58, 59.The operation of the device described above is similar to that of the previous embodiments and makes it possible to obtain a valve lift with a large amplitude using the high cams H which directly actuate the catches 58 and 59 which are pressed against the rods 2a of the valves 2. As visible in FIG. 14, in the working position of the movable levers 58 and 59 and erased from the fixed lever F, the T-shaped lever F is kept in contact with the cam B under the effect of the force applied by the elastic member 48, which allows the formation of a space "e" by which the part 10 of the lever F is distant from the fingers 38, 39 of the latches 58, 59.

Ici encore la variation d'amplitude de la levée de soupape s'effectue de façon identique à celle décrite plus haut.Here again the variation in amplitude of the valve lift takes place in an identical manner to that described above.

Pour obtenir une levée de soupape à amplitude plus faible, les linguets 58 et 59 sont placés, comme visible sur la figure 15, dans leur position effacée, de façon que les extrémités de la partie transversale 10 du levier F viennent en contact avec des surfaces d'appui S des doigts de contact 38 et 39 des linguets 58 et 59, et afin que ces derniers transmettent aux soupapes 2 le mouvement du levier F qui est provoqué par la came B à profil bas.To obtain a valve lift at lower amplitude, the latches 58 and 59 are placed, as visible in FIG. 15, in their retracted position, so that the ends of the transverse part 10 of the lever F come into contact with surfaces S support of the contact fingers 38 and 39 of the latches 58 and 59, and so that the latter transmit to the valves 2 the movement of the lever F which is caused by the low profile cam B.

Ici encore, c'est grâce à la liaison par simple contact entre les leviers, les deux leviers 58 et 59 servant d'intermédiaire au levier F pour transmettre le mouvement des cames, ainsi que grâce à l'utilisation judicieuse des ressorts de rappel de la soupape et au choix approprié du déplacement par coulissement du guide 24 dans la culasse 1 que l'on a obtenu un dispositif avantageux et efficace comparé à l'art antérieur.Here again, it is thanks to the connection by simple contact between the levers, the two levers 58 and 59 serving as an intermediary for the lever F to transmit the movement of the cams, as well as thanks to the judicious use of the return springs of the valve and the appropriate choice of displacement by sliding of the guide 24 in the cylinder head 1 that an advantageous and effective device has been obtained compared to the prior art.

On a par conséquent réalisé un dispositif de levée de soupape à amplitude variable qui est simple et grâce auquel le changement d'amplitude de la levée est obtenu avec l'un des leviers articulés sur un pivot fixe. En outre, ce dispositif permet de faciliter le réglage des jeux fonctionnels et permet également d'agir sur les soupapes sans porte-à-faux.Consequently, a valve lift device with variable amplitude is simple and thanks to which the change in amplitude of the lift is obtained with one of the levers articulated on a fixed pivot. In addition, this device makes it easier to adjust the functional clearances and also makes it possible to act on the valves without overhang.

On précisera ici que le dispositif conforme à l'invention peut également permettre la levée d'une soupape unique, dont la tige viendrait de préférence en contact avec le milieu de la partie transversale décrite plus haut.It will be specified here that the device according to the invention can also allow the lifting of a single valve, the stem of which would preferably come into contact with the middle of the transverse part described above.

Claims (7)

  1. Device with a variable lift amplitude for at least one valve of an internal combustion engine and of the type comprising a control shaft (7) with two cams one (H) of which is high and the other one(B) is low, a lever provided at each control cam, both levers extending in nearly parallel relationship with each one having one portion which is pivotally connected to the cylinder head (1) through the medium of a pivot and one end which is connected to the valve (2) so that it may exert an axial thrust upon the latter against a spring (6) for returning the valve (2), one of the pivots being mounted to be movable in accordance with operating parameters of the engine and under the effect of a selecting member (27) between an active position in which the associated lever co-operates with the corresponding cam (H) and a retracted position, each lever being capable of a movement between a working position in contact with its control cam (B, H) and a retracted position so that both levers act alternately and selectively upon the valve (2), one of them acting upon the latter through the medium of the other lever (F ; M ; 58, 59) in the retracted position while co-operating through a bearing surface (S) with the end of this lever which is in contact (18, 19) with the valve, characterized in that the said portion of each lever which is pivotally connected to the cylinder head being its end opposite to that which is connected to the valve, the control shaft (7) comprises a third cam (B) exhibiting a profile identical with that of the low cam (B) which is disposed so that the high cam (H) be located between both cams (B) with a low profile and that each low cam (B) co-operates respectively with one of the two parallel legs (8, 9) of an O-shaped lever (F) which is mounted onto stationary pivots (13, 14) and which comprises at least one surface (18, 19) bearing upon at least one valve (2), this surface being formed at the bottom face of a transverse part (10) of the O-shaped lever and which connects both parallel legs (8, 9) on the one side as well as one bent part (11) connecting them on the other side.
  2. Device according to claim 1, characterized in that the high cam (H) co-operates with a straight lever or pawl (M) which extends between two guiding faces (22, 23) of the aforesaid parallel legs, the said pawl (M) being mounted onto the cylinder head (1) through the medium of a movable pivot (15) fastened onto a sliding guide (24) and comprising a finger (12) for contact with a bearing surface (S) which extends on its lower face plumb with the aforesaid transverse part (10).
  3. Device with a variable lift amplitude for at least one valve of an internal combustion engine and of the type comprising a control shaft (7) with two cams one (H) of which is high and the other one (B) is low, a lever provided at each control cam, both levers extending in nearly parallel relationship with each one having a portion which is pivotally connected to the cylinder head (1) through the medium of a pivot and one end which is connected to the valve (2) so that it may exert an axial thrust upon the latter against a spring (6) for the return of the valve (2), one of the pivots being mounted to be movable in accordance with operating parameters of the engine and under the effect of a selecting member (27) between an active position in which the associated lever co-operates with the corresponding cam (H) and a retracted position, each lever being capable of a movement between a working position in contact with its control cam (B, H) and a retracted position so that both levers act alternately and selectively upon the valve (2), one of them acting upon the latter through the medium of the other lever (F ; M ; 58, 59) in the retracted position while co-operating through a bearing surface (S) with that end of this lever which is in contact (18, 19) with the valve, characterized in that with the said portion pivotally connected to the cylinder head of each lever being its end opposite to that which is connected to the valve, the high cam (H) co-operates with a T-shaped lever (M) the longitudinal leg of which is pivotally connected to a sliding pivot (15) and the transverse part (10) of which comprises at its top face two bearing surfaces (S) for two pawls (8, 9) which cooperate respectively with one of the low cams (B) and comprises at its bottom face at least one surface (18, 19) of contact with at least one valve (2).
  4. Device according to claim 3, characterized in that the transverse part of the T-shaped lever comprises at its lower face two surfaces (18, 19) of contact with two valves (2) and which are provided at the bearing surfaces (S) of the pawls.
  5. Device according to one of claims 3 or 4, characterized in that each straight pawl (8, 9) is mounted onto a stationary pivot (13, 14) and comprises at its free end a contact finger (38, 39) which projects from the pawl at one of the aforesaid bearing surfaces (S).
  6. Device with a variable lift amplitude for at least one valve of an internal combustion engine and of the type comprising a control shaft (7) with two cams one (H) of which is high and the other one (B) is low, a lever provided at each control cam, both levers extending in nearly parallel relationship with each one having a portion which is pivotally connected to the cylinder head (1) through the medium of a pivot and one end which is connected to the valve (2) so that it may exert an axial thrust upon the latter against a spring (6) for the return of the valve (2), one of the pivots being mounted to be movable in accordance with operating parameters of the engine and under the effect of a selecting member (27) between an active position in which the associated lever co-operates with the corresponding cam (H) and a retracted position, each lever being capable of a movement between a working position in contact with its control cam (B, H) and a retracted position so that both levers act alternately and selectively upon the valve (2), one of them acting upon the latter through the medium of the other lever (F ; M ; 58, 59) in the retracted position while co-operating through a bearing surface (S) with that end of this lever which is in contact (18, 19) with the valve, characterized in that with the said portion pivotally connected to the cylinder head of each lever being its end opposite to that which is connected to the valve, the control shaft (7) comprises a third cam (B) exhibiting a profile identical with that of the high cam (H) and which is disposed so that the low cam (B) be located between two cams with a high profile, the said cam with a low profile (B) cooperating with one of the T-shaped levers (F) which is pivotally connected to a stationary pivot (13) and the transverse part (10) of which extends up to be plumb with two valves (2) whereas each high cam (H) co-operates with a straight lever or pawl (58, 59) one end of which is mounted onto a pivot (15) sliding within the cylinder head (1) and the other end of which comprises a contact finger (38, 39) which exhibits at its bottom face a contact surface (18, 19) for one of the valves (2) and exhibits at its top face a bearing surface (S) for one of the ends of the transverse part (10) of the T-shaped lever(F).
  7. Device according to claim 6, characterized in that an elastic member (48) is fastened to each stationary pivot (13, 14) and exerts upon the corresponding lever (8, 9, F) a force having a tendency to apply the said lever (F, 8, 9) upon the cam (B) associated therewith.
EP91401347A 1990-06-21 1991-05-24 Variable amplitude device for the lift of at least one internal combustion engine valve Expired - Lifetime EP0462853B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9007799A FR2663682B1 (en) 1990-06-21 1990-06-21 VARIABLE AMPLITUDE DEVICE FOR LIFTING AT LEAST ONE VALVE OF AN INTERNAL COMBUSTION ENGINE.
FR9007799 1990-06-21

Publications (2)

Publication Number Publication Date
EP0462853A1 EP0462853A1 (en) 1991-12-27
EP0462853B1 true EP0462853B1 (en) 1994-06-22

Family

ID=9397879

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91401347A Expired - Lifetime EP0462853B1 (en) 1990-06-21 1991-05-24 Variable amplitude device for the lift of at least one internal combustion engine valve

Country Status (3)

Country Link
EP (1) EP0462853B1 (en)
DE (1) DE69102591T2 (en)
FR (1) FR2663682B1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006031945A1 (en) * 2006-07-11 2008-01-24 Schaeffler Kg Adjustable rocker arm for valve train of internal combustion engine, has coupler located in recess of levers and brought in contact with levers for case of coupling in sectionwise, and lost-motion spring directly mounted on supporting unit

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2674287B1 (en) * 1991-03-19 1993-07-23 Peugeot HYDRAULIC CONTROL FOR LIFTING MECHANISM WITH VARIABLE AMPLITUDE OF AT LEAST ONE VALVE OF INTERNAL COMBUSTION ENGINE.
DE4212844A1 (en) * 1992-04-16 1993-10-21 Audi Ag Valve actuation mechanism for an internal combustion engine
EP0638706A1 (en) * 1993-08-05 1995-02-15 Bayerische Motoren Werke Aktiengesellschaft Valve actuating mechanism of an internal combustion engine
FR2731043B1 (en) * 1995-02-24 1997-04-04 Renault VARIABLE DISTRIBUTION DEVICE FOR INTERNAL COMBUSTION ENGINE
NL1001267C2 (en) * 1995-09-22 1997-03-25 Netherlands Car Bv Combustion engine.
DE19730814A1 (en) * 1997-07-18 1999-01-21 Schaeffler Waelzlager Ohg Periodically actuated valve gear for gas or fluid exchange
DE19930573A1 (en) * 1999-07-02 2001-01-04 Schaeffler Waelzlager Ohg Valve drive for internal combustion engine, which can be coupled to provide three different stroke runs and has switching rod intersecting support element radially
DE19930574A1 (en) * 1999-07-02 2001-01-04 Schaeffler Waelzlager Ohg Valve drive for internal combustion engine, which can be coupled to provide three different stroke runs for gas exchange valves
FR2815377B1 (en) * 2000-10-13 2003-02-07 Peugeot Citroen Automobiles Sa MULTIPLE CONFIGURATION VALVE DISTRIBUTION CONTROL DEVICE
DE10137490A1 (en) * 2001-07-31 2003-02-13 Ina Schaeffler Kg Valve control device for internal combustion engine has a multi-part drag lever with primary lever and a secondary lever on each side of same and actuated by second cam
AUPR723501A0 (en) * 2001-08-23 2001-09-13 G.P. Embelton & Co. Pty. Ltd. Sound insulation product
AU2002328657C1 (en) * 2001-08-23 2009-01-08 G.P. Embelton & Co. Pty. Ltd. Sound insulation panel
DE102005033018A1 (en) 2005-07-15 2007-01-25 Schaeffler Kg Valve train for an internal combustion engine
DE102009037496A1 (en) * 2009-08-13 2011-02-17 Schaeffler Technologies Gmbh & Co. Kg Valve gear of an internal combustion engine
GB2526554A (en) 2014-05-27 2015-12-02 Eaton Srl Valvetrain with variable valve actuation
DE102018204450B4 (en) 2018-03-22 2021-12-23 Vitesco Technologies GmbH Method for testing a variable valve lift control of an internal combustion engine
CN109184845A (en) * 2018-11-06 2019-01-11 吉林大学 Magnetoelectricity drives rotating variable valve assembly

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2199079A (en) * 1986-12-27 1988-06-29 Honda Motor Co Ltd Multiple cylinder i.c. engine valve gear
EP0405927A1 (en) * 1989-06-30 1991-01-02 Suzuki Kabushiki Kaisha Valve moving mechanism for four-cycle engine
EP0442460A1 (en) * 1990-02-16 1991-08-21 FERRARI S.p.A. Variable timing system, particularly for an internal combustion engine
WO1991012415A1 (en) * 1990-02-16 1991-08-22 Group Lotus Plc Cam mechanisms

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2753197A1 (en) * 1976-12-15 1978-06-22 Eaton Corp VALVE CONTROL DEVICE
DE3119133A1 (en) * 1981-05-14 1982-12-02 Anton Ing.(grad.) 8492 Furth Pfeifer Valve control device for four-stroke internal combustion engines
US4475489A (en) * 1981-05-27 1984-10-09 Honda Giken Kogyo Kabushiki Kaisha Variable valve timing device for an internal combustion engine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2199079A (en) * 1986-12-27 1988-06-29 Honda Motor Co Ltd Multiple cylinder i.c. engine valve gear
EP0405927A1 (en) * 1989-06-30 1991-01-02 Suzuki Kabushiki Kaisha Valve moving mechanism for four-cycle engine
EP0442460A1 (en) * 1990-02-16 1991-08-21 FERRARI S.p.A. Variable timing system, particularly for an internal combustion engine
WO1991012415A1 (en) * 1990-02-16 1991-08-22 Group Lotus Plc Cam mechanisms

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
BUSSIEN, "Automobiltechnisches Handbuch", pp.161-165 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006031945A1 (en) * 2006-07-11 2008-01-24 Schaeffler Kg Adjustable rocker arm for valve train of internal combustion engine, has coupler located in recess of levers and brought in contact with levers for case of coupling in sectionwise, and lost-motion spring directly mounted on supporting unit

Also Published As

Publication number Publication date
FR2663682B1 (en) 1992-10-16
EP0462853A1 (en) 1991-12-27
FR2663682A1 (en) 1991-12-27
DE69102591T2 (en) 1995-02-09
DE69102591D1 (en) 1994-07-28

Similar Documents

Publication Publication Date Title
EP0462853B1 (en) Variable amplitude device for the lift of at least one internal combustion engine valve
FR2822419A1 (en) VEHICLE SEAT HAVING A JOINT MECHANISM
FR2750186A1 (en) CONTROL MECHANISM OF A ROTATING MEMBER BY MEANS OF A PIVOTING HANDLE, AND SEAT EQUIPPED WITH SUCH A MECHANISM
FR2700580A1 (en) Variable control system for valves in an internal combustion engine.
EP0265316A1 (en) Locking system of a linear device for the rapid adjustment and blocking of a mobile part with respect to a fixed part
FR2766139A1 (en) Hinge assembly for vehicle seat
FR2589545A1 (en) PARKING DEVICE FOR AUTOMATIC TRANSMISSION
FR2649942A1 (en) ARTICULATING FERRULE FOR SEATS, ESPECIALLY FOR SEATS OF MOTOR VEHICLES COMPRISING AN ADJUSTABLE BACKREST AND CAPABLE OF PIVOTING FREELY
EP0488857B1 (en) Internal control device for gearbox
EP0298056A2 (en) Bending press for sheets
FR2910082A1 (en) HYDRAULIC LOCKING DEVICE FOR LIFT ARMS
EP0025786B1 (en) Retractable ski brake
FR2663078A1 (en) Device for the moving arm and variable amplitude for lifting an internal combustion engine valve
FR2884191A1 (en) Motor vehicle`s seat articulation mechanism, has rising step in shape of wedge pushing back locking step in locking position when rising step is in active position and unlocking position when rising step is in pitch position
EP0216647B1 (en) Valve control system for an internal-combustion engine with disconnectable rockers
EP0505231B1 (en) Hydraulic control for variable amplitude lift mechanism of at least one internal combustion engine valve
FR2724975A1 (en) IC engine variable valve lift device
EP0154584B1 (en) Device for automatic recovery of play for clutch
FR2566836A1 (en) VALVE OPERATION MECHANISM FOR INTERNAL COMBUSTION ENGINE
FR2630068A1 (en) DEVICE FOR DRIVING A WINDSCREEN WIPER BLADE FOR PUTTING INTO THE WITHDRAWAL POSITION
FR2583105A1 (en) Variable control device for an internal combustion engine valve with a stem
FR2731043A1 (en) Variable valve control for vehicle IC-engine
FR2728936A1 (en) Variable distribution valve control mechanism for IC engine
FR2570123A1 (en) Device for the variable control of a valve with a stem for an internal combustion engine
EP0739767B1 (en) Automatic and manual level control device for a motor vehicle axle with hydropneumatic suspension or analog

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE GB IT

17P Request for examination filed

Effective date: 19920215

17Q First examination report despatched

Effective date: 19930316

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE GB IT

REF Corresponds to:

Ref document number: 69102591

Country of ref document: DE

Date of ref document: 19940728

ITF It: translation for a ep patent filed

Owner name: DE DOMINICIS & MAYER S.R.L.

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19940927

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19950515

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19950523

Year of fee payment: 5

26N No opposition filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19960524

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19960524

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19970201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050524