EP1748194A1 - Pressure amplification device for a hydraulic actuator in an internal combustion engine and engine incorporating such device - Google Patents

Pressure amplification device for a hydraulic actuator in an internal combustion engine and engine incorporating such device Download PDF

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Publication number
EP1748194A1
EP1748194A1 EP06300590A EP06300590A EP1748194A1 EP 1748194 A1 EP1748194 A1 EP 1748194A1 EP 06300590 A EP06300590 A EP 06300590A EP 06300590 A EP06300590 A EP 06300590A EP 1748194 A1 EP1748194 A1 EP 1748194A1
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EP
European Patent Office
Prior art keywords
control
pressure
high pressure
low pressure
cylinder
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.)
Withdrawn
Application number
EP06300590A
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German (de)
French (fr)
Inventor
Emmanuel Devaud
Gwennaël Favennec
Jacques Obert
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Renault SAS
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Renault SAS
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Publication date
Application filed by Renault SAS filed Critical Renault SAS
Publication of EP1748194A1 publication Critical patent/EP1748194A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/08—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
    • F04B9/10—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid
    • F04B9/109—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers
    • F04B9/111—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers with two mechanically connected pumping members
    • F04B9/113—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers with two mechanically connected pumping members reciprocating movement of the pumping members being obtained by a double-acting liquid motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/12—Fluid oscillators or pulse generators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B3/00—Intensifiers or fluid-pressure converters, e.g. pressure exchangers; Conveying pressure from one fluid system to another, without contact between the fluids

Definitions

  • the present invention relates to a pressure amplification device for a hydraulic actuator located in a heat engine and a heat engine incorporating such a device.
  • a variable compression ratio engine whose device for adjusting the compression ratio comprises a cam control shaft, pivotable to change the position of the top dead center of the piston and thus to vary the compression ratio of the motor.
  • the rotation of the control shaft at the position corresponding to the operating conditions of the engine is controlled by a hydraulic actuator with two pressure chambers fed with hydraulic fluid under pressure from a source of hydraulic fluid under pressure.
  • pressure control means are provided for variably controlling the pressure of the hydraulic fluid supplied to the hydraulic actuator according to the operating conditions of the engine. More specifically, the hydraulic actuator is actuated by means of the hydraulic fluid under pressure supplied by a pump, driven by the motor by means of a belt coupled to a pulley secured to the crankshaft.
  • a solenoid valve controlled by the pressure control means makes it possible to supply one or the other of the two pressure chambers of the actuator in order to control the displacement of this actuator.
  • variable compression ratio control device for an internal combustion engine comprising an engine-driven accessory hydraulic pump and a two-chamber hydraulic fluid accumulator system separated by a movable piston.
  • a first chamber is supplied with high pressure hydraulic fluid by an accessory pump driven by the engine.
  • a second chamber is supplied with low pressure hydraulic fluid by a lubricating pump of the engine.
  • the low pressure hydraulic fluid is compressed in the hydraulic fluid accumulator system by means of the high pressure hydraulic fluid contained in the first chamber and feeds a hydraulic actuator via an unloading valve, controlled by an actuator control module allowing to adjust the flow of hydraulic fluid through the unloading valve.
  • the two described devices make it possible to supply high pressure hydraulic fluid to a hydraulic actuator situated in a heat engine, these have the disadvantage that the high pressure of the hydraulic fluid is, each time, provided by a hydraulic pump driven by the engine.
  • the pump must be sized to provide sufficient hydraulic fluid flow, already at low engine speed. At high engine speed, the pump is then in excess of flow, this excess flow corresponding to a lost energy.
  • the devices described, implementing high hydraulic fluid pressures have energy yields that are not satisfactory.
  • the object of the invention is therefore to provide a pressure amplification device for a hydraulic actuator located in a heat engine to correct the aforementioned drawbacks and in particular to minimize the level of pressure at the source to reduce the losses associated with the excess flow while ensuring a high level of pressure at the hydraulic actuator.
  • the pressure amplification device according to the invention can be supplied with low pressure hydraulic fluid and provide high pressure hydraulic fluid compressed by means of the differential piston, regardless of the heat engine.
  • said distributor comprises bistable means for holding said control spool in position in said first and second control positions.
  • bistable means for holding in position it is advantageous to provide a bistable behavior of the control spool, which is stable in each of its control positions, despite the action of the hydraulic control fluid passing through the dispenser.
  • said bistable means for holding said control spool in position comprise first and second position-retaining recesses formed on said control spool, and a position-keeping blasting, secured to said sleeve and cooperating with said recess holding in position.
  • bistable behavior of the slide is thus advantageously carried out mechanically. Keeping the control spool in position is thus robust and economical.
  • said mechanical coupling means comprise a support comprising first and second control fingers penetrating into said differential piston cylinder so as to be pushed by said differential piston when approaching the first and second positions respectively. end of race said piston, and first and second control projections adapted to push, under the effect of the displacement of the first and second control finger respectively, said control spool so as to bring said drawer from a control position up to the other control position.
  • the differential piston controls, during its course, the movement of the slide from its first control position to its second control position and vice versa.
  • the pressure amplification device further comprises means for rapidly switching the control position of said drawer.
  • said fast switching means comprise a tooth formed on said support and resilient support means cooperating with said tooth, so that a translation of said support under the effect of the displacement of one of said fingers control causes, during a charging time, compression of said resilient support means, said support being then, during a discharge time, pushed by the sliding of said elastic means on said tooth, so as to push said control spool by means of said first, respectively second, control projection from the first, respectively second, control position of said drawer to the second, respectively the first, control position of said drawer.
  • the fast switching means are realized in purely mechanical form and in a simple manner.
  • said first, respectively second, control projection being in contact with said first, respectively second, end of said control spool, the second, respectively first, control projection is spaced from said second, respectively first, end of said spool. control by means of a clearance, so that during said charging time of said resilient support means, said differential piston can drive said support without moving said control spool and during said discharge time said resilient support means, the sliding of said support causes the sliding of said control slide.
  • said differential piston cylinder further comprises a second high pressure cylinder made in the extension of said low pressure cylinder, opposite said first high pressure cylinder, and a second high pressure head in the extension of said low pressure head, driven by said low pressure head and slidably mounted in said second high pressure cylinder so as to delimit with said second high pressure cylinder a second high pressure chamber, said second high pressure chamber having a second low pressure hydraulic fluid inlet and a second high hydraulic fluid outlet pressure.
  • the differential piston compresses hydraulic fluid during each of its paths in the differential piston cylinder. This ensures a flow of hydraulic fluid output substantially larger than a single high pressure chamber.
  • first and second secondary outlet ducts opening respectively into said first and second high pressure chambers, and provided with a first and second non-return valve, respectively, towards the first and second high pressure chambers. , come together to form a main outlet pipe.
  • the invention also relates to a heat engine comprising a hydraulic actuator and a pressure amplification device as described above in all its variants, remarkable in that said hydraulic control fluid and / or said low pressure hydraulic fluid is the lubricating oil said engine.
  • FIGS. 1 and 2 diagrammatically show a device of FIG. pressure amplification for a hydraulic actuator located in a heat engine according to the invention, respectively in a first and a second phase of operation corresponding, respectively, to a first and a second control position of the distributor spool.
  • the pressure amplification device 10 as shown in FIG. 1 comprises a frame 11 inside which a differential piston cylinder 12 having a low-pressure cylinder 14 and first 16a and second 16b high-pressure cylinders formed has been formed.
  • the high pressure cylinders 16a, 16b being here, preferably, formed on opposite sides of said low pressure cylinder 14.
  • the differential piston cylinder 12 also comprises a differential piston 18 comprising a piston head low pressure 20 being able to slide tightly in the low pressure cylinder 14 and dividing the internal volume of the low pressure cylinder 14 into first 22a and second 22b low pressure chambers.
  • a first high-pressure piston head 24a is mounted in the extension of the low-pressure piston head 20, here, directly on the first front surface 26a (shown in dashed lines in the figures) of the low-pressure piston head 20, so as to slide, in a sealed manner, in the first high-pressure cylinder 16a so as to define with the first low-pressure cylinder 16a a first high-pressure chamber 28a.
  • a second high-pressure piston head 24b is mounted in the extension of the low-pressure piston head 20, here directly on the second end surface 26b (shown in dashed lines in the figures) of the low piston head pressure 20, so as to slide, in a sealed manner, in the second high pressure cylinder 16b so as to define with the second low-pressure cylinder 16b a second high pressure chamber 28b.
  • the first high pressure chamber 28a comprises, in this case, a single first port 29a of low pressure hydraulic fluid inlet and high pressure hydraulic fluid outlet.
  • the second high pressure chamber 28b comprises, in this case, a single second port 29b of low pressure hydraulic fluid inlet and high pressure hydraulic fluid outlet.
  • low pressure hydraulic fluid inlet ports and separate high pressure hydraulic fluid outlet ports may be provided.
  • the low-pressure chambers and the high-pressure, cylindrical chambers are substantially coaxial, here with axis x-x '.
  • the useful front surface 30 of the low-pressure piston head 20 is greater than the first useful front surface 32a of the first high-pressure piston head 24a, this first useful front surface 32a being here, preferably, substantially equal to the second useful front surface 32b of the second high-pressure piston head 24b.
  • the pressure amplification device 10 also comprises a low-pressure hydraulic control fluid distributor 34, also provided inside the frame 11, comprising a bushing 36 and a control spool 38, able to slide in the bushing 36, substantially parallel to the x-x 'axis, between the first and second control positions.
  • the distributor also comprises first 40a and second 40b control inputs, first 42a and second 42b control outputs and a discharge output 44. As shown in FIG.
  • the first low-pressure chamber 22a in fluid communication with the first control input 40a of the distributor 34 via the first control output 42a, while the second low-pressure chamber 22b is then isolated from the second control input 40b and in communication with fluid with the discharge outlet 44 of the distributor 34 via the second control output 42b.
  • the second low pressure chamber 22b In the second control position of the drawer 38 shown in FIG. 2, the second low pressure chamber 22b is in fluid communication with the second control input 40b of the distributor 34 via the second control output 42b, while the first low chamber pressure 22a, is then isolated from the first control input 40a and in fluid communication with the discharge outlet 44 of the distributor 34 via the first control output 42a.
  • first 46a and second 46b position holding recesses are made, in this case in the form of circular grooves, the first and second circular grooves 46a, 46b cooperating with a ball device 48 mounted on a solidarity spring of the frame 11 forming a holding shot in position 48 so as to maintain the slide 38 in its first, respectively second, control position.
  • means for holding the control spool 38 in position are provided.
  • other solutions are conceivable for producing these means for holding the control spool 38 in position, these allowing the distributor to operate in a bistable manner and thus escape the parasitic forces that may appear in particular at the control spool 38, such as jet forces or dynamic forces related to the environment of the device 10.
  • the pressure amplification device 10 furthermore comprises means for mechanically coupling the spool 38 and the differential piston 18 so as to control the switching of the position of the spool 38 by means of the differential piston 18.
  • these means of mechanical coupling comprise a support 50, which in this case has a shape of "U", and which comprises first 52a and second 52b lateral branches and a central branch 54, substantially parallel to the axis x-x ', first 56a and second 56b control fingers being mounted at the free end 58a, 58b of the first 52a, respectively second 52b, lateral branch so as to be substantially coaxial with each other and substantially parallel to the axis x-x '.
  • first 56a and second 56b control fingers respectively enter the first 22a and second 22b low pressure chamber of the differential piston cylinder 12, so that the differential piston 18 approaching its end positions results in , the first 56a, respectively the second 56b, control finger when the differential piston 18 moves in the direction of the arrow Fa, respectively in the direction of the arrow Fb, thus controlling the sliding substantially along the x-axis ', support 50 relative to the frame 11.
  • a first control projection 60a is produced, substantially parallel to the axis x-x ', so that the first control projection 60a can cooperate with a first end. 62a of the drawer 38 so as to push said drawer 38 from its first control position to its second control position.
  • a second control projection 60b is produced, substantially parallel to the x-x 'axis, so that the second control projection 60b can cooperate with a second end. 62b of the drawer 38 so as to push said drawer 38 from its second control position to its first control position.
  • the distributor 34 is disposed in the space delimited by the side branches 52a, 52b and central 54 of the support 50 and by the differential piston cylinder 12.
  • the first 60a and second 60b control projections are made such that when the first control projection 60a, respectively the second control projection 60b, is in contact with the first end 62a of the drawer 38, respectively the second end 62b of the drawer 38, a set 64b, respectively a set 64a, separates the second end 62b of the drawer 38 and the second control projection 60b, respectively the first end 62a of the drawer and the first control projection 60a.
  • first 66a and second 66b switching recesses are arranged, separated by a triangular tooth 68, so that the first 66a, respectively second 66b , the switching recess receives a ball of a switching shot 70 in a first, respectively second, end position of the support 50 in which the first control projection 60a, respectively the second control projection 60b, bears on the first end.
  • 62a of the drawer 38 respectively on the second end 62b of the drawer 38, the drawer 38 being in its first control position, respectively in its second control position.
  • the switching recesses 66a, 66b may be replaced, for example, by abutment devices provided on each side of the frame 11 to cooperate with the lateral branches 52a, 52b of the support 50 or, in a less favorable embodiment, removed.
  • the pressure amplification device 10 is coupled to a discharge circuit 71 comprising first 72a and second 72b secondary outlet lines, opening on the one hand, respectively in the first low pressure chamber 28a and in the second low pressure chamber 28b, and joining on the other hand so as to form a main outlet pipe 74.
  • a first exhaust check valve 76a is mounted, performing the anti-return function to the first high pressure chamber 28a.
  • a second exhaust check valve 76b is mounted, performing the anti-return function to the second high pressure chamber 28b.
  • a first supply line 78a is stitched onto the first outlet line 72a, a first supply check valve 80a being mounted on this first supply line 78a so as to fulfill the function of anti -back to the power source 82.
  • a second supply line 78b is stitched onto the second outlet line 72b, a second supply check valve 80b being mounted on this second supply line 78b so as to fulfill the function of non-return to power source 82.
  • the pressure amplification device 10 is coupled to a primary circuit 84 comprising an inlet main pipe 85 dividing upstream of the distributor 34 into first 86a and second 86b secondary inlet conduit opening at the level of the first 40a, respectively of the second 40b, control input of the distributor 34.
  • the engine lubrication circuit fulfills the function of a source of hydraulic control fluid 88, the discharge outlet 44 then preferably opening into the hydraulic fluid tank 90 of the lubricating circuit of the engine. engine.
  • the implementation of the engine lubrication circuit as a source of hydraulic control fluid advantageously, to have a relatively large source flow.
  • the maximum pressure in the first high-pressure chamber 28a is directly related to the differential piston cylinder 12 and more particularly to the ratio between the useful front surface 30 of the low-pressure piston head 20 and the useful front surface 32a of the first head high pressure piston 24a.
  • the displacement of the differential piston 18 generates a depression in the second high pressure chamber 28b, which causes the opening of the second supply check valve 80b and the aspiration of the hydraulic fluid from the supply source 82 into hydraulic fluid.
  • the second high-pressure hydraulic chamber 28b thus fills substantially at the same time as the first chamber Low pressure hydraulic 28a is empty. It may be noted that the supply of the high pressure chamber 28b is facilitated if the supply source 82 is under pressure.
  • the differential piston 18 On approaching the end-of-travel position of the differential piston 18 in the direction of arrow F0, the differential piston 18 comes into contact with the first control finger 56a and then drives it towards the right of FIG. control finger 56a being rigidly mounted on the support 50, its displacement causes the translation, along the x-x 'axis, to the right of FIG. 1, of the support 50.
  • the slide 38 the distributor 34 remains stationary thanks to the clearance 64b which prevents the second control projection 60b of the support 50 from driving the slide 34 to the right of FIG. 1.
  • the switching projection 70 is dimensioned so that from the moment where this comm billing The auger 70 passes through a discharge time, reached when the log ball 70 extends beyond the tip of the tooth 68, at which point this switching balloon 70 expands to retract the log ball 70 into the second switch recess 66b. , the energy restored by this switching shot 70 is sufficient to overcome the maintaining shot in position 48 of the control spool 38 of the distributor 34.
  • the control spool has a bistable operation, escaping any pressure equilibrium at the differential piston 18 which would have the effect of blocking the movement of the differential piston 18 and therefore also the control spool 38.
  • the drawer 38 of the dispenser 34 reaches its second control position shown in FIG. 2, pushed by the second control projection 60b until the holding beam in position 48 enters the second holding recess in position 44b. .
  • the first control input 40a of the valve 34 is closed, while the second control input 40b of the valve 34 is brought into fluid communication with the second control output. 42b of the distributor 34 and that the second control output 42a of the distributor 34 is in fluid communication with the discharge outlet 44 of the distributor.
  • the supply of the first low-pressure chamber 22a is cut off, the second low-pressure chamber 22b is fed to the contrary and the control hydraulic fluid contained in the first low-pressure chamber 22a is evacuated.
  • the displacement of the differential piston 18 in the direction of the arrow Fb generates a depression in the first high pressure chamber 28a, which causes the opening of the first supply check valve 80a and the suction of the low pressure hydraulic fluid from the supply source 82, when the pressure in the first high pressure chamber 28a becomes lower than the pressure of the supply source 82.
  • the first high pressure hydraulic chamber 28a thus fills substantially at the same time as the second low hydraulic chamber pressure 28b is empty.
  • the differential piston 18 On approaching the end position of the differential piston 18 in the direction of the arrow Fb, the differential piston 18 comes into contact with the second control finger 56b and then drives it to the left of FIG. second control finger 56b being rigidly mounted on the support 50, its displacement causes the translation, along the x-x 'axis, to the left of Figure 2, the support 50.
  • the log ball 70 exits the second switch recess 66b and the log 70 is compressed by sliding the ball on the second face of the tooth 68.
  • the slide 38 of the dispenser 34 remains stationary thanks to the clearance 64a which prevents the first control projection 60a of the support 50 from driving the slide 34 towards the left of FIG. 2.
  • the switching projection 70 dimensioned so that the energy restored by this projection of switching 70 d the time of discharge is sufficient to overcome the holding mantle in position 48 of the control spool 38 of the dispenser 34, returns the spool 38 of the dispenser 34 to its first control position.
  • the device according to the invention can be made solely mechanically and hydraulically, that is to say that it comprises for example no electronic element, which facilitates its integration into the engine.
  • the pressure amplification device according to the invention provides, at the efficiency, the energy it receives.
  • the pressure being amplified the returned flow is lower than the flow taken.
  • the flow taken is generally not constant but instead depends on the engine speed.
  • the pressure amplification device according to the invention can supply a hydraulic actuator through a hydraulic accumulator. This accumulator must have the capacity to provide the necessary flow for a complete actuation of the hydraulic actuator thus ensuring an optimal response time of the actuator.
  • a device comprising only a high pressure chamber instead of two high pressure chambers as has been presented above, or a device in which the high pressure heads and the low pressure head would not be coaxial or else a device where the high pressure heads would not be made directly on the low pressure head but only coupled to this low pressure head (via a shaft for example).
  • this tooth may have a less regular shape than the shape of a triangle.
  • this tooth has a peak tip. More preferably, this tooth is substantially symmetrical.
  • the switchgearing device that is to say the device comprising a ball mounted on a spring, may also be replaced by any resilient support means adapted to cooperate with the switching recesses and the tooth, as, for example, illustrative and nonlimiting example, an elastic metal tongue.
  • the holding shot in the drawer position is integral with the control spool and where the holding recesses in position are formed inside the bushing of the dispenser.
  • the holding shot in position can be replaced by any bistable means for holding in position, such as, by way of illustrative and non-limiting example, an elastic metal blade.
  • the dispenser may also include two discharge outlets, each of the discharge outlets being adapted to be placed in fluid communication with one of the low pressure chambers of the differential piston cylinder.
  • the pressure amplification device according to the invention can be implemented with any type of hydraulic actuator, in particular the hydraulic actuators arranged inside a heat engine, as, for illustrative example and not limiting, a hydraulic actuator for controlling the stroke of a piston in a variable compression ratio engine.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The device (10) has a differential piston cylinder (12) with a differential piston (18) sliding between low pressure chambers (22a, 22b), and a high pressure chamber (28a). A control hydraulic fluid distributor (34) present control positions selectively controlling the refilling or the emptying of the low pressure chambers. A mechanical coupling unit mechanically couples a valve spool (38) and the piston so as to control the commutation of the position of the spool using the piston. An independent claim is also included for a heat engine comprising a hydraulic actuator and a pressure amplification device.

Description

La présente invention se rapporte à un dispositif d'amplification de pression pour un actionneur hydraulique situé dans un moteur thermique et à un moteur thermique incorporant un tel dispositif.The present invention relates to a pressure amplification device for a hydraulic actuator located in a heat engine and a heat engine incorporating such a device.

Dans un moteur à taux de compression variable ou pour actionner un dispositif de décalage d'un arbre à cames, il est connu de mettre en oeuvre un actionneur hydraulique dans un moteur thermique. Ce type d'actionneurs doit disposer d'un niveau de pression de fluide hydraulique relativement important tout en conservant un encombrement limité.In a variable compression ratio engine or to actuate a shift device of a camshaft, it is known to implement a hydraulic actuator in a heat engine. This type of actuator must have a relatively high level of hydraulic fluid pressure while maintaining a limited size.

Ainsi, on connaît du document EP 1 418 322 , un moteur à taux de compression variable dont le dispositif pour régler le taux de compression comprend un arbre de contrôle d'une came, apte à pivoter afin de modifier la position du point mort haut du piston et donc de faire varier le taux de compression du moteur. La rotation de l'arbre de contrôle à la position correspondant aux conditions de fonctionnement du moteur est commandée par un actionneur hydraulique à deux chambres de pression alimentées en fluide hydraulique sous pression par une source de fluide hydraulique sous pression. Enfin, des moyens de contrôle de la pression sont prévus pour contrôler de manière variable la pression du fluide hydraulique fournie à l'actionneur hydraulique en fonction des conditions de fonctionnement du moteur. Plus précisément, l'actionneur hydraulique est actionné au moyen du fluide hydraulique sous pression fournie par une pompe, entraînée par le moteur au moyen d'une courroie couplée à une poulie solidaire du vilebrequin. Une électrovanne commandée par les moyens de contrôle de la pression permet d'alimenter l'une ou l'autre des deux chambres de pression de l'actionneur afin de commander le déplacement de cet actionneur.So, we know of the document EP 1 418 322 , a variable compression ratio engine whose device for adjusting the compression ratio comprises a cam control shaft, pivotable to change the position of the top dead center of the piston and thus to vary the compression ratio of the motor. The rotation of the control shaft at the position corresponding to the operating conditions of the engine is controlled by a hydraulic actuator with two pressure chambers fed with hydraulic fluid under pressure from a source of hydraulic fluid under pressure. Finally, pressure control means are provided for variably controlling the pressure of the hydraulic fluid supplied to the hydraulic actuator according to the operating conditions of the engine. More specifically, the hydraulic actuator is actuated by means of the hydraulic fluid under pressure supplied by a pump, driven by the motor by means of a belt coupled to a pulley secured to the crankshaft. A solenoid valve controlled by the pressure control means makes it possible to supply one or the other of the two pressure chambers of the actuator in order to control the displacement of this actuator.

Par ailleurs, le document US 6622672 divulgue un dispositif de contrôle du taux de compression variable pour un moteur à combustion interne comprenant une pompe hydraulique d'accessoire entraînée par le moteur et un système d'accumulateur de fluide hydraulique à deux chambres séparées par un piston mobile. Une première chambre est alimentée en fluide hydraulique haute pression par une pompe d'accessoires entraînée par le moteur. Une deuxième chambre est alimentée en fluide hydraulique basse pression par une pompe de lubrification du moteur. Le fluide hydraulique basse pression est comprimé dans le système d'accumulateur de fluide hydraulique au moyen du fluide hydraulique haute pression contenu dans la première chambre et alimente un actionneur hydraulique via une valve de déchargement, contrôlée par un module de contrôle de l'actionneur permettant de régler le débit de fluide hydraulique au travers de la valve de déchargement.In addition, the document US 6622672 discloses a variable compression ratio control device for an internal combustion engine comprising an engine-driven accessory hydraulic pump and a two-chamber hydraulic fluid accumulator system separated by a movable piston. A first chamber is supplied with high pressure hydraulic fluid by an accessory pump driven by the engine. A second chamber is supplied with low pressure hydraulic fluid by a lubricating pump of the engine. The low pressure hydraulic fluid is compressed in the hydraulic fluid accumulator system by means of the high pressure hydraulic fluid contained in the first chamber and feeds a hydraulic actuator via an unloading valve, controlled by an actuator control module allowing to adjust the flow of hydraulic fluid through the unloading valve.

Bien que les deux dispositifs décrits permettent de fournir du fluide hydraulique haute pression à un actionneur hydraulique situé dans un moteur thermique, ceux-ci présentent l'inconvénient que la haute pression du fluide hydraulique est, chaque fois, fournie par une pompe hydraulique entraînée par le moteur thermique. Or, la pompe doit être dimensionnée de manière à fournir suffisamment de débit de fluide hydraulique, déjà à bas régime moteur. A haut régime moteur, la pompe se trouve alors en excès de débit, cet excès de débit correspondant à une énergie perdue. Ainsi, les dispositifs décrits, mettant en oeuvre des pressions de fluide hydraulique importantes, présentent des rendements énergétiques qui ne sont pas satisfaisants.Although the two described devices make it possible to supply high pressure hydraulic fluid to a hydraulic actuator situated in a heat engine, these have the disadvantage that the high pressure of the hydraulic fluid is, each time, provided by a hydraulic pump driven by the engine. However, the pump must be sized to provide sufficient hydraulic fluid flow, already at low engine speed. At high engine speed, the pump is then in excess of flow, this excess flow corresponding to a lost energy. Thus, the devices described, implementing high hydraulic fluid pressures, have energy yields that are not satisfactory.

Le but de l'invention est donc de proposer un dispositif d'amplification de pression pour un actionneur hydraulique situé dans un moteur thermique corrigeant les inconvénients susnommés et permettant notamment de minimiser le niveau de pression à la source pour réduire les pertes liées à l'excès de débit tout en assurant un niveau de pression élevé au niveau de l'actionneur hydraulique.The object of the invention is therefore to provide a pressure amplification device for a hydraulic actuator located in a heat engine to correct the aforementioned drawbacks and in particular to minimize the level of pressure at the source to reduce the losses associated with the excess flow while ensuring a high level of pressure at the hydraulic actuator.

On atteint ce but de l'invention au moyen d'un dispositif d'amplification de pression pour un actionneur hydraulique situé dans un moteur thermique remarquable en ce qu'il comporte :

  • un vérin à piston différentiel comportant un cylindre basse pression, au moins un premier cylindre haute pression dans le prolongement dudit cylindre basse pression, et un piston différentiel comprenant une tête basse pression, pouvant coulisser de manière étanche dans ledit cylindre basse pression et divisant le volume intérieur du cylindre basse pression en des première et seconde chambres basse pression, et une première tête haute pression entraînée par ladite tête basse pression et montée coulissante dans ledit premier cylindre haute pression de manière à délimiter avec ledit premier cylindre haute pression une première chambre haute pression, ladite première chambre haute pression comportant une première entrée de fluide hydraulique basse pression et une première sortie de fluide hydraulique haute pression,
  • un distributeur de fluide hydraulique de commande comportant une douille et un tiroir de commande apte à coulisser dans ladite douille entre des première et seconde positions de commande dans lesquelles, ladite première, respectivement seconde, chambre basse pression est en communication de fluide avec une première, respectivement une seconde, entrée de commande du distributeur, la seconde, respectivement première, chambre basse pression étant alors isolée de ladite seconde, respectivement première, entrée de commande du distributeur et en communication de fluide avec une sortie de décharge dudit distributeur,
  • des moyens de couplage mécanique dudit tiroir de commande et dudit piston différentiel de manière à commander la commutation de la position dudit tiroir de commande au moyen dudit piston différentiel.
This object of the invention is achieved by means of a pressure amplification device for a hydraulic actuator located in a remarkable thermal engine in that it comprises:
  • a differential piston cylinder comprising a low pressure cylinder, at least a first high pressure cylinder in the extension of said low pressure cylinder, and a differential piston comprising a low pressure head, being able to slide in a sealed manner in said low pressure cylinder and dividing the volume inside the low pressure cylinder in first and second low pressure chambers, and a first high pressure head driven by said low pressure head and slidably mounted in said first high pressure cylinder so as to define with said first high pressure cylinder a first high pressure chamber said first high pressure chamber having a first low pressure hydraulic fluid inlet and a first high pressure hydraulic fluid outlet,
  • a control hydraulic fluid distributor comprising a bushing and a control slide slidable in said bushing between first and second control positions in which said first or second low pressure chamber is in fluid communication with a first, respectively a second control input of the distributor, the second, respectively first, low pressure chamber being then isolated from said second, respectively first control input of the distributor and in fluid communication with a discharge outlet of said distributor,
  • mechanical coupling means of said control spool and said differential piston so as to control the switching of the position of said control spool by means of said differential piston.

Comme on le verra plus en détail dans la suite de la description, avantageusement, le dispositif d'amplification de la pression selon l'invention peut être alimenté en fluide hydraulique basse pression et fournir du fluide hydraulique haute pression comprimé au moyen du piston différentiel, indépendamment du moteur thermique.As will be seen in more detail in the following description, advantageously, the pressure amplification device according to the invention can be supplied with low pressure hydraulic fluid and provide high pressure hydraulic fluid compressed by means of the differential piston, regardless of the heat engine.

De préférence, ledit distributeur comporte des moyens bistables de maintien en position dudit tiroir de commande dans lesdites première et seconde position de commande.Preferably, said distributor comprises bistable means for holding said control spool in position in said first and second control positions.

Avec de tels moyens bistables de maintien en position, on assure, avantageusement, un comportement bistable du tiroir de commande, celui-ci étant stable dans chacune de ses positions de commande, malgré l'action du fluide hydraulique de commande traversant le distributeur.With such bistable means for holding in position, it is advantageous to provide a bistable behavior of the control spool, which is stable in each of its control positions, despite the action of the hydraulic control fluid passing through the dispenser.

De manière préférée, lesdits moyens bistables de maintien en position dudit tiroir de commande comprennent des premier et second renfoncements de maintien en position ménagés sur ledit tiroir de commande, et un billage de maintien en position, solidaire de ladite douille et coopérant avec lesdits renfoncements de maintien en position.Preferably, said bistable means for holding said control spool in position comprise first and second position-retaining recesses formed on said control spool, and a position-keeping blasting, secured to said sleeve and cooperating with said recess holding in position.

On réalise ainsi, de manière avantageuse, le comportement bistable du tiroir de manière mécanique. Le maintien en position du tiroir de commande est ainsi robuste et économique.The bistable behavior of the slide is thus advantageously carried out mechanically. Keeping the control spool in position is thus robust and economical.

De manière préférée, lesdits moyens de couplage mécanique comportent un support comportant des premier et second doigts de commande pénétrant dans ledit vérin à piston différentiel de manière à être poussés par ledit piston différentiel à l'approche de la première, respectivement de la seconde, position de fin de course dudit piston, et des première et seconde saillies de commande aptes à pousser, sous l'effet du déplacement du premier, respectivement du second, doigt de commande, ledit tiroir de commande de manière à amener ledit tiroir depuis une position de commande jusqu'à l'autre position de commande.Preferably, said mechanical coupling means comprise a support comprising first and second control fingers penetrating into said differential piston cylinder so as to be pushed by said differential piston when approaching the first and second positions respectively. end of race said piston, and first and second control projections adapted to push, under the effect of the displacement of the first and second control finger respectively, said control spool so as to bring said drawer from a control position up to the other control position.

Ainsi, le piston différentiel commande, au cours de sa course, le déplacement du tiroir depuis sa première position de commande vers sa seconde position de commande et réciproquement.Thus, the differential piston controls, during its course, the movement of the slide from its first control position to its second control position and vice versa.

De préférence, le dispositif d'amplification de pression selon l'invention comporte en outre des moyens de commutation rapide de la position de commande dudit tiroir.Preferably, the pressure amplification device according to the invention further comprises means for rapidly switching the control position of said drawer.

Avec de tels moyens de commutation rapide de la position de commande du tiroir, il est possible d' échapper aux éventuels efforts parasites agissant sur le piston différentiel et le tiroir de commande qui pourraient aboutir à un blocage du dispositif.With such means of rapid switching of the control position of the slide, it is possible to escape any parasitic forces acting on the differential piston and the control spool which could result in a blockage of the device.

De manière préférée, lesdits moyens de commutation rapide comportent une dent ménagée sur ledit support et des moyens d'appui élastiques coopérant avec ladite dent, de manière à ce qu'une translation dudit support sous l'effet du déplacement d'un desdits doigts de commande provoque, durant un temps de charge, une compression desdits moyens d'appui élastiques, ledit support étant ensuite, durant un temps de décharge, poussé par le glissement desdits moyens élastiques sur ladite dent, de manière à pousser ledit tiroir de commande au moyen de ladite première, respectivement seconde, saillie de commande depuis la première, respectivement seconde, position de commande dudit tiroir jusqu'à la seconde, respectivement la première, position de commande dudit tiroir.Preferably, said fast switching means comprise a tooth formed on said support and resilient support means cooperating with said tooth, so that a translation of said support under the effect of the displacement of one of said fingers control causes, during a charging time, compression of said resilient support means, said support being then, during a discharge time, pushed by the sliding of said elastic means on said tooth, so as to push said control spool by means of said first, respectively second, control projection from the first, respectively second, control position of said drawer to the second, respectively the first, control position of said drawer.

On réalise ainsi, de manière avantageuse, les moyens de commutation rapide sous forme purement mécanique et de manière simple.Advantageously, the fast switching means are realized in purely mechanical form and in a simple manner.

De manière préférée, ladite première, respectivement seconde, saillie de commande étant en contact avec ladite première, respectivement seconde, extrémité dudit tiroir de commande, la seconde, respectivement première, saillie de commande est espacée de ladite seconde, respectivement première, extrémité dudit tiroir de commande au moyen d'un jeu, de manière à ce que, durant ledit temps de charge desdits moyens d'appui élastiques, ledit piston différentiel puisse entraîner ledit support sans déplacer ledit tiroir de commande et à ce que, durant ledit temps de décharge desdits moyens d'appui élastiques, le coulissement dudit support entraîne le coulissement dudit tiroir de commande.Preferably, said first, respectively second, control projection being in contact with said first, respectively second, end of said control spool, the second, respectively first, control projection is spaced from said second, respectively first, end of said spool. control by means of a clearance, so that during said charging time of said resilient support means, said differential piston can drive said support without moving said control spool and during said discharge time said resilient support means, the sliding of said support causes the sliding of said control slide.

Ainsi, de manière avantageuse, il est possible de réaliser, avantageusement, une commutation rapide de la position du tiroir de commande, en échappant aux éventuels efforts parasites agissant sur le piston différentiel et le tiroir de commande.Thus, advantageously, it is possible to achieve, advantageously, rapid switching of the position of the control spool, escaping any parasitic forces acting on the differential piston and the control spool.

De préférence, ledit vérin à piston différentiel comporte en outre un second cylindre haute pression réalisé dans le prolongement dudit cylindre basse pression, opposé audit premier cylindre haute pression, et une seconde tête haute pression dans le prolongement de ladite tête basse pression, entraînée par ladite tête basse pression et montée coulissante dans ledit second cylindre haute pression de manière à délimiter avec ledit second cylindre haute pression une seconde chambre haute pression, ladite seconde chambre haute pression comportant une seconde entrée de fluide hydraulique basse pression et une seconde sortie de fluide hydraulique haute pression.Preferably, said differential piston cylinder further comprises a second high pressure cylinder made in the extension of said low pressure cylinder, opposite said first high pressure cylinder, and a second high pressure head in the extension of said low pressure head, driven by said low pressure head and slidably mounted in said second high pressure cylinder so as to delimit with said second high pressure cylinder a second high pressure chamber, said second high pressure chamber having a second low pressure hydraulic fluid inlet and a second high hydraulic fluid outlet pressure.

Ainsi, de manière avantageuse, le piston différentiel comprime du fluide hydraulique au cours de chacun de ses trajets dans le vérin à piston différentiel. On assure ainsi un débit de fluide hydraulique en sortie sensiblement plus important qu'avec une seule chambre haute pression.Thus, advantageously, the differential piston compresses hydraulic fluid during each of its paths in the differential piston cylinder. This ensures a flow of hydraulic fluid output substantially larger than a single high pressure chamber.

De manière préférée, des première et seconde conduites secondaires de sortie débouchant respectivement dans lesdites première et seconde chambres haute pression, et pourvues d'un premier, respectivement d'un second, clapet d'anti-retour vers les première et seconde chambres haute pression, se rejoignent pour former une conduite principale de sortie.Preferably, first and second secondary outlet ducts opening respectively into said first and second high pressure chambers, and provided with a first and second non-return valve, respectively, towards the first and second high pressure chambers. , come together to form a main outlet pipe.

On assure de la sorte l'isolation des chambres haute pression où la pression est inférieure à la pression du fluide hydraulique dans la conduite principale de sortie.This ensures the insulation of high pressure chambers where the pressure is lower than the pressure of the hydraulic fluid in the main outlet pipe.

L'invention concerne également un moteur thermique comprenant un actionneur hydraulique et un dispositif d'amplification de pression tel que décrit ci-avant dans toutes ses variantes, remarquable en ce que ledit fluide hydraulique de commande et/ou ledit fluide hydraulique basse pression est de l'huile lubrifiant ledit moteur.The invention also relates to a heat engine comprising a hydraulic actuator and a pressure amplification device as described above in all its variants, remarkable in that said hydraulic control fluid and / or said low pressure hydraulic fluid is the lubricating oil said engine.

De la sorte, on évite avantageusement tout problème de compatibilité d'huile dans le moteur thermique.In this way, any problem of oil compatibility in the heat engine is advantageously avoided.

D'autres avantages et caractéristiques de l'invention apparaîtront de la description qui va suivre, présentée uniquement à titre d'exemple illustratif et non limitatif, en regard des figures ci-annexées, sur lesquelles les figures 1 et 2 représentent schématiquement un dispositif d'amplification de pression pour un actionneur hydraulique situé dans un moteur thermique selon l'invention, respectivement dans une première et une deuxième phase de fonctionnement correspondant, respectivement, à une première et une seconde position de commande du tiroir du distributeur.Other advantages and characteristics of the invention will emerge from the description which follows, presented solely by way of illustrative and non-limiting example, with reference to the appended figures, in which FIGS. 1 and 2 diagrammatically show a device of FIG. pressure amplification for a hydraulic actuator located in a heat engine according to the invention, respectively in a first and a second phase of operation corresponding, respectively, to a first and a second control position of the distributor spool.

Le dispositif d'amplification de pression 10 tel que représenté sur la figure 1 comporte un bâti 11 à l'intérieur duquel on a ménagé un vérin à piston différentiel 12 comportant un cylindre basse pression 14 et des premier 16a et second 16b cylindres haute pression formés dans le prolongement du cylindre basse pression 14, les cylindres haute pression 16a, 16b étant ici, de préférence, réalisés sur des côtés opposés dudit cylindre basse pression 14. Le vérin à piston différentiel 12 comporte également un piston différentiel 18 comprenant une tête de piston basse pression 20 pouvant coulisser de manière étanche dans le cylindre basse pression 14 et divisant le volume intérieur du cylindre basse pression 14 en des première 22a et seconde 22b chambres basse pression. Une première tête de piston haute pression 24a est montée dans le prolongement de la tête de piston basse pression 20, ici, directement sur la première surface frontale 26a (représentée partiellement en pointillés sur les figures) de la tête de piston basse pression 20, de manière à pouvoir coulisser, de manière étanche, dans le premier cylindre haute pression 16a de manière à délimiter avec le premier cylindre basse pression 16a une première chambre haute pression 28a. De manière équivalente, une seconde tête de piston haute pression 24b est montée dans le prolongement de la tête de piston basse pression 20, ici, directement sur la seconde surface frontale 26b (représentée partiellement en pointillés sur les figures) de la tête de piston basse pression 20, de manière à pouvoir coulisser, de manière étanche, dans le second cylindre haute pression 16b de manière à délimiter avec le second cylindre basse pression 16b une seconde chambre haute pression 28b.The pressure amplification device 10 as shown in FIG. 1 comprises a frame 11 inside which a differential piston cylinder 12 having a low-pressure cylinder 14 and first 16a and second 16b high-pressure cylinders formed has been formed. in the extension of the low pressure cylinder 14, the high pressure cylinders 16a, 16b being here, preferably, formed on opposite sides of said low pressure cylinder 14. The differential piston cylinder 12 also comprises a differential piston 18 comprising a piston head low pressure 20 being able to slide tightly in the low pressure cylinder 14 and dividing the internal volume of the low pressure cylinder 14 into first 22a and second 22b low pressure chambers. A first high-pressure piston head 24a is mounted in the extension of the low-pressure piston head 20, here, directly on the first front surface 26a (shown in dashed lines in the figures) of the low-pressure piston head 20, so as to slide, in a sealed manner, in the first high-pressure cylinder 16a so as to define with the first low-pressure cylinder 16a a first high-pressure chamber 28a. Equivalently, a second high-pressure piston head 24b is mounted in the extension of the low-pressure piston head 20, here directly on the second end surface 26b (shown in dashed lines in the figures) of the low piston head pressure 20, so as to slide, in a sealed manner, in the second high pressure cylinder 16b so as to define with the second low-pressure cylinder 16b a second high pressure chamber 28b.

La première chambre haute pression 28a comporte, en l'espèce, un unique premier orifice 29a d'entrée de fluide hydraulique basse pression et de sortie de fluide hydraulique haute pression.The first high pressure chamber 28a comprises, in this case, a single first port 29a of low pressure hydraulic fluid inlet and high pressure hydraulic fluid outlet.

De même, la seconde chambre haute pression 28b comporte, en l'espèce, un unique second orifice 29b d'entrée de fluide hydraulique basse pression et de sortie de fluide hydraulique haute pression.Similarly, the second high pressure chamber 28b comprises, in this case, a single second port 29b of low pressure hydraulic fluid inlet and high pressure hydraulic fluid outlet.

Bien entendu, d'autres modes de réalisation des chambres sont possibles. On peut notamment prévoir des orifices d'entrée de fluide hydraulique basse pression et de sortie de fluide hydraulique haute pression distincts.Of course, other embodiments of the chambers are possible. In particular, low pressure hydraulic fluid inlet ports and separate high pressure hydraulic fluid outlet ports may be provided.

De préférence, comme cela est représenté sur les figures, les chambres basse pression et les chambres haute pression, cylindriques, sont sensiblement coaxiales, ici, d'axe x-x'.Preferably, as shown in the figures, the low-pressure chambers and the high-pressure, cylindrical chambers are substantially coaxial, here with axis x-x '.

Il est à noter que la surface frontale utile 30 de la tête de piston basse pression 20 est supérieure à la première surface frontale utile 32a de la première tête de piston haute pression 24a, cette première surface frontale utile 32a étant ici, de préférence, sensiblement égale à la seconde surface frontale utile 32b de la seconde tête de piston haute pression 24b.It should be noted that the useful front surface 30 of the low-pressure piston head 20 is greater than the first useful front surface 32a of the first high-pressure piston head 24a, this first useful front surface 32a being here, preferably, substantially equal to the second useful front surface 32b of the second high-pressure piston head 24b.

Le dispositif d'amplification de pression 10 comporte également un distributeur 34 de fluide hydraulique de commande, à basse pression, également ménagé à l'intérieur du bâti 11, comportant une douille 36 et un tiroir de commande 38, apte à coulisser dans la douille 36, sensiblement parallèlement à l'axe x-x', entre les première et seconde positions de commande. Le distributeur comporte également des première 40a et seconde 40b entrées de commande, des première 42a et seconde 42b sorties de commande et une sortie de décharge 44. Comme cela est représenté à la figure 1, dans la première position de commande du tiroir 38, la première chambre basse pression 22a est en communication de fluide avec la première entrée de commande 40a du distributeur 34 via la première sortie de commande 42a, tandis que la seconde chambre basse pression 22b est alors isolée de la seconde entrée de commande 40b et en communication de fluide avec la sortie de décharge 44 du distributeur 34 via la seconde sortie de commande 42b. Dans la seconde position de commande du tiroir 38 représentée à la figure 2, la seconde chambre basse pression 22b est en communication de fluide avec la seconde entrée de commande 40b du distributeur 34 via la seconde sortie de commande 42b, tandis que la première chambre basse pression 22a, est alors isolée de la première entrée commande 40a et en communication de fluide avec la sortie de décharge 44 du distributeur 34 via la première sortie de commande 42a.The pressure amplification device 10 also comprises a low-pressure hydraulic control fluid distributor 34, also provided inside the frame 11, comprising a bushing 36 and a control spool 38, able to slide in the bushing 36, substantially parallel to the x-x 'axis, between the first and second control positions. The distributor also comprises first 40a and second 40b control inputs, first 42a and second 42b control outputs and a discharge output 44. As shown in FIG. 1, in the first control position of the drawer 38, the first low-pressure chamber 22a is in fluid communication with the first control input 40a of the distributor 34 via the first control output 42a, while the second low-pressure chamber 22b is then isolated from the second control input 40b and in communication with fluid with the discharge outlet 44 of the distributor 34 via the second control output 42b. In the second control position of the drawer 38 shown in FIG. 2, the second low pressure chamber 22b is in fluid communication with the second control input 40b of the distributor 34 via the second control output 42b, while the first low chamber pressure 22a, is then isolated from the first control input 40a and in fluid communication with the discharge outlet 44 of the distributor 34 via the first control output 42a.

Sur le tiroir 38, des premier 46a et second 46b renfoncements de maintien en position sont réalisés, en l'espèce sous forme de rainures circulaires, les première et seconde rainures circulaires 46a, 46b coopérant avec un dispositif 48 de bille montée sur un ressort solidaire du bâti 11 formant un billage de maintien en position 48 de manière à maintenir le tiroir 38 dans sa première, respectivement seconde, position de commande. On réalise ainsi des moyens de maintien en position du tiroir de commande 38. Bien entendu, d'autres solutions sont envisageables pour réaliser ces moyens de maintien en position du tiroir de commande 38, ceux-ci permettant au distributeur de fonctionner de manière bistable et d'échapper ainsi aux efforts parasites pouvant apparaître notamment au niveau du tiroir de commande 38, comme les forces de jet ou les forces dynamiques liées à l'environnement du dispositif 10.On the slide 38, first 46a and second 46b position holding recesses are made, in this case in the form of circular grooves, the first and second circular grooves 46a, 46b cooperating with a ball device 48 mounted on a solidarity spring of the frame 11 forming a holding shot in position 48 so as to maintain the slide 38 in its first, respectively second, control position. Thus, means for holding the control spool 38 in position are provided. Of course, other solutions are conceivable for producing these means for holding the control spool 38 in position, these allowing the distributor to operate in a bistable manner and thus escape the parasitic forces that may appear in particular at the control spool 38, such as jet forces or dynamic forces related to the environment of the device 10.

Le dispositif d'amplification de pression 10 comporte par ailleurs, des moyens de couplage mécanique du tiroir 38 et du piston différentiel 18 de manière à commander la commutation de la position du tiroir 38 au moyen du piston différentiel 18. De préférence, ces moyens de couplage mécanique comportent un support 50, qui, en l'espèce présente une forme de « U », et qui comprend des première 52a et seconde 52b branches latérales et une branche centrale 54, sensiblement parallèle à l'axe x-x', des premier 56a et second 56b doigts de commande étant montés à l'extrémité libre 58a, 58b de la première 52a, respectivement seconde 52b, branche latérale de manière à être sensiblement coaxiaux entre eux et sensiblement parallèles à l'axe x-x'. Ces premier 56a et second 56b doigts de commande pénètrent respectivement dans la première 22a et la seconde 22b chambre basse pression du vérin à piston différentiel 12, de manière à ce que le piston différentiel 18 à l'approche de ses positions de fin de course entraîne, le premier 56a, respectivement le second 56b, doigt de commande lorsque le piston différentiel 18 se déplace dans le sens de la flèche Fa, respectivement dans le sens de la flèche Fb, commandant ainsi le coulissement, sensiblement selon l'axe x-x', du support 50 par rapport au bâti 11.The pressure amplification device 10 furthermore comprises means for mechanically coupling the spool 38 and the differential piston 18 so as to control the switching of the position of the spool 38 by means of the differential piston 18. Preferably, these means of mechanical coupling comprise a support 50, which in this case has a shape of "U", and which comprises first 52a and second 52b lateral branches and a central branch 54, substantially parallel to the axis x-x ', first 56a and second 56b control fingers being mounted at the free end 58a, 58b of the first 52a, respectively second 52b, lateral branch so as to be substantially coaxial with each other and substantially parallel to the axis x-x '. These first 56a and second 56b control fingers respectively enter the first 22a and second 22b low pressure chamber of the differential piston cylinder 12, so that the differential piston 18 approaching its end positions results in , the first 56a, respectively the second 56b, control finger when the differential piston 18 moves in the direction of the arrow Fa, respectively in the direction of the arrow Fb, thus controlling the sliding substantially along the x-axis ', support 50 relative to the frame 11.

Par ailleurs, sur la première branche latérale 52a du support 50, une première saillie de commande 60a est réalisée, sensiblement parallèle à l'axe x-x', de manière à ce que la première saillie de commande 60a puisse coopérer avec une première extrémité 62a du tiroir 38 de manière à pousser ledit tiroir 38 depuis sa première position de commande jusqu'à sa seconde position de commande.Furthermore, on the first lateral branch 52a of the support 50, a first control projection 60a is produced, substantially parallel to the axis x-x ', so that the first control projection 60a can cooperate with a first end. 62a of the drawer 38 so as to push said drawer 38 from its first control position to its second control position.

De même, sur la seconde branche latérale 52b du support 50, une seconde saillie de commande 60b est réalisée, sensiblement parallèle à l'axe x-x', de manière à ce que la seconde saillie de commande 60b puisse coopérer avec une seconde extrémité 62b du tiroir 38 de manière à pousser ledit tiroir 38 depuis sa seconde position de commande jusqu'à sa première position de commande.Similarly, on the second lateral branch 52b of the support 50, a second control projection 60b is produced, substantially parallel to the x-x 'axis, so that the second control projection 60b can cooperate with a second end. 62b of the drawer 38 so as to push said drawer 38 from its second control position to its first control position.

Ainsi, le distributeur 34 est disposé dans l'espace délimité par les branches latérales 52a, 52b et centrale 54 du support 50 et par le vérin à piston différentiel 12.Thus, the distributor 34 is disposed in the space delimited by the side branches 52a, 52b and central 54 of the support 50 and by the differential piston cylinder 12.

Les première 60a et seconde 60b saillies de commande sont réalisées de telle sorte que lorsque la première saillie de commande 60a, respectivement la seconde saillie de commande 60b, est en contact avec la première extrémité 62a du tiroir 38, respectivement la seconde extrémité 62b du tiroir 38, un jeu 64b, respectivement un jeu 64a, sépare la seconde extrémité 62b du tiroir 38 et la seconde saillie de commande 60b, respectivement la première extrémité 62a du tiroir et la première saillie de commande 60a.The first 60a and second 60b control projections are made such that when the first control projection 60a, respectively the second control projection 60b, is in contact with the first end 62a of the drawer 38, respectively the second end 62b of the drawer 38, a set 64b, respectively a set 64a, separates the second end 62b of the drawer 38 and the second control projection 60b, respectively the first end 62a of the drawer and the first control projection 60a.

Comme cela est représenté sur les figures, au niveau de la branche centrale 54 du support 50, des premier 66a et second 66b renfoncements de commutation sont ménagés, séparés par une dent triangulaire 68, de manière à ce que le premier 66a, respectivement second 66b, renfoncement de commutation reçoive une bille d'un billage de commutation 70 dans une première, respectivement seconde, position extrême du support 50 dans laquelle la première saillie de commande 60a, respectivement la seconde saillie de commande 60b, est en appui sur la première extrémité 62a du tiroir 38, respectivement sur la seconde extrémité 62b du tiroir 38, le tiroir 38 se trouvant dans sa première position de commande, respectivement dans sa seconde position de commande. Par billage, on entend un dispositif de bille montée sur un ressort qui, en l'espèce, est solidaire du bâti 11.As shown in the figures, at the central branch 54 of the support 50, first 66a and second 66b switching recesses are arranged, separated by a triangular tooth 68, so that the first 66a, respectively second 66b , the switching recess receives a ball of a switching shot 70 in a first, respectively second, end position of the support 50 in which the first control projection 60a, respectively the second control projection 60b, bears on the first end. 62a of the drawer 38, respectively on the second end 62b of the drawer 38, the drawer 38 being in its first control position, respectively in its second control position. By blasting means a ball device mounted on a spring which, in this case, is integral with the frame 11.

Les renfoncements de commutation 66a, 66b peuvent être remplacés, par exemple, par des dispositifs de butée ménagés de chaque côté du bâti 11 pour coopérer avec les branches latérales 52a, 52b du support 50 voire, dans un mode de réalisation moins favorable, supprimés.The switching recesses 66a, 66b may be replaced, for example, by abutment devices provided on each side of the frame 11 to cooperate with the lateral branches 52a, 52b of the support 50 or, in a less favorable embodiment, removed.

Par ailleurs, le dispositif d'amplification de pression 10 est couplé à un circuit d'évacuation 71 comportant des première 72a et seconde 72b conduites secondaires de sortie, débouchant d'une part, respectivement dans la première chambre basse pression 28a et dans la seconde chambre basse pression 28b, et se rejoignant d'autre part de manière à former une conduite principale de sortie 74.Furthermore, the pressure amplification device 10 is coupled to a discharge circuit 71 comprising first 72a and second 72b secondary outlet lines, opening on the one hand, respectively in the first low pressure chamber 28a and in the second low pressure chamber 28b, and joining on the other hand so as to form a main outlet pipe 74.

Sur la première conduite secondaire de sortie 72a, un premier clapet anti-retour d'évacuation 76a est monté, remplissant la fonction d'anti-retour vers la première chambre haute pression 28a.On the first secondary outlet pipe 72a, a first exhaust check valve 76a is mounted, performing the anti-return function to the first high pressure chamber 28a.

De même, sur la seconde conduite secondaire de sortie 72b, un second clapet anti-retour d'évacuation 76b est monté, remplissant la fonction d'anti-retour vers la seconde chambre haute pression 28b.Similarly, on the second secondary outlet pipe 72b, a second exhaust check valve 76b is mounted, performing the anti-return function to the second high pressure chamber 28b.

Par ailleurs, une première conduite d'alimentation 78a est piquée sur la première conduite secondaire de sortie 72a, un premier clapet anti-retour d'alimentation 80a étant monté sur cette première conduite d'alimentation 78a de manière à remplir la fonction d'anti-retour vers la source d'alimentation 82.Furthermore, a first supply line 78a is stitched onto the first outlet line 72a, a first supply check valve 80a being mounted on this first supply line 78a so as to fulfill the function of anti -back to the power source 82.

De manière similaire, une seconde conduite d'alimentation 78b est piquée sur la seconde conduite secondaire de sortie 72b, un second clapet anti-retour d'alimentation 80b étant monté sur cette seconde conduite d'alimentation 78b de manière à remplir la fonction d'anti-retour vers la source d'alimentation 82.Similarly, a second supply line 78b is stitched onto the second outlet line 72b, a second supply check valve 80b being mounted on this second supply line 78b so as to fulfill the function of non-return to power source 82.

De préférence, la source d'alimentation 82 en fluide hydraulique à basse pression pour les chambres haute pression 28a, 28b peut être constitué par :

  • la source de fluide hydraulique du circuit de lubrification du moteur thermique ;
  • la source d'alimentation en fluide hydraulique de commande des chambres basse pression 22a, 22b.
Preferably, the low-pressure hydraulic fluid supply source 82 for the high-pressure chambers 28a, 28b may consist of:
  • the hydraulic fluid source of the lubrication circuit of the heat engine;
  • the control hydraulic fluid supply source for the low pressure chambers 22a, 22b.

Avec cette dernière solution, il est possible d'augmenter sensiblement le débit du fluide hydraulique en sortie des chambres haute pression par rapport à la solution consistant à alimenter les chambres haute pression avec la source de fluide hydraulique du circuit de lubrification du moteur thermique. Cependant, cette solution nécessite également d'augmenter le débit de fluide hydraulique prélevé du circuit de lubrification du moteur.With this latter solution, it is possible to substantially increase the flow rate of the hydraulic fluid at the outlet of the high pressure chambers relative to the solution of supplying the high pressure chambers with the source of hydraulic fluid of the lubrication circuit of the engine. However, this solution also requires increasing the flow of hydraulic fluid taken from the engine lubrication circuit.

Enfin, le dispositif d'amplification de pression 10 est couplé à un circuit primaire 84 comportant une conduite principale d'entrée 85 se divisant en amont du distributeur 34 en des première 86a et seconde 86b conduite secondaire d'entrée débouchant au niveau de la première 40a, respectivement de la seconde 40b, entrée de commande du distributeur 34.Finally, the pressure amplification device 10 is coupled to a primary circuit 84 comprising an inlet main pipe 85 dividing upstream of the distributor 34 into first 86a and second 86b secondary inlet conduit opening at the level of the first 40a, respectively of the second 40b, control input of the distributor 34.

Le fonctionnement et les avantages du dispositif d'amplification de pression 10 qui vient d'être décrit, résultent directement de la description qui précède.The operation and advantages of the pressure amplification device 10 which has just been described result directly from the foregoing description.

Dans l'exemple présenté ci-après, le circuit de lubrification du moteur remplit la fonction de source de fluide hydraulique de commande 88, la sortie de décharge 44 débouchant alors, de préférence, dans le réservoir 90 de fluide hydraulique du circuit de lubrification du moteur.In the example presented hereinafter, the engine lubrication circuit fulfills the function of a source of hydraulic control fluid 88, the discharge outlet 44 then preferably opening into the hydraulic fluid tank 90 of the lubricating circuit of the engine. engine.

La mise en oeuvre du circuit de lubrification du moteur en tant que source de fluide hydraulique de commande, permet, avantageusement, d'avoir un débit de la source relativement important.The implementation of the engine lubrication circuit as a source of hydraulic control fluid, advantageously, to have a relatively large source flow.

Sur la figure 1, le tiroir 38 du distributeur 34 est dans sa première position de commande.In Figure 1, the drawer 38 of the distributor 34 is in its first control position.

Dans cette première position de commande du tiroir 38, la première chambre basse pression 22a peut se remplir de fluide hydraulique de commande. Dans ces conditions, et tant qu'aucun débit n'est débité en sortie du dispositif d'amplification de la pression, la pression du fluide hydraulique dans la première chambre haute pression 28a augmente afin d'assurer l'équilibre du piston différentiel 18. Dans cette situation d'équilibre du piston différentiel 18 et en négligeant les contre-efforts du fait de la présence de fluide hydraulique dans la seconde chambre haute pression 28b et dans la seconde chambre basse pression 22b, qui est en communication de fluide avec la sortie de décharge 44 du distributeur 34, la pression maximale dans la première chambre haute pression 28a vaut sensiblement : P HP_ max = P com ⋅ S s

Figure imgb0001

où :

  • PHP_max représente la pression maximale dans la première chambre haute pression 28a,
  • Pcom la pression du fluide hydraulique de commande dans la première chambre basse pression 22a,
  • S la surface frontale utile 30 de la tête de piston basse pression 20, et
  • s la surface frontale utile 32a de la première tête de piston haute pression 24a.
In this first control position of the slide 38, the first low-pressure chamber 22a can be filled with hydraulic control fluid. Under these conditions, and as long as no flow is output from the amplification device of the pressure, the pressure of the hydraulic fluid in the first high pressure chamber 28a increases to ensure the equilibrium of the differential piston 18. In this equilibrium situation of the differential piston 18 and neglecting the counter-forces due to the presence of hydraulic fluid in the second high pressure chamber 28b and in the second low pressure chamber 22b, which is in fluid communication with the discharge outlet 44 of the distributor 34, the maximum pressure in the first high pressure chamber 28a is substantially: P HP_ max = P com ⋅ S s
Figure imgb0001
or :
  • P HP_max represents the maximum pressure in the first high pressure chamber 28a,
  • P com the pressure of the control hydraulic fluid in the first low pressure chamber 22a,
  • S the useful front surface 30 of the low pressure piston head 20, and
  • s the useful front surface 32a of the first high-pressure piston head 24a.

Ainsi, la pression maximale dans la première chambre haute pression 28a est directement lié au vérin à piston différentiel 12 et plus particulièrement au rapport entre la surface frontale utile 30 de la tête de piston basse pression 20 et la surface frontale utile 32a de la première tête de piston haute pression 24a.Thus, the maximum pressure in the first high-pressure chamber 28a is directly related to the differential piston cylinder 12 and more particularly to the ratio between the useful front surface 30 of the low-pressure piston head 20 and the useful front surface 32a of the first head high pressure piston 24a.

Cependant, tant qu'aucun débit n'apparaît dans la conduite principale de sortie 74, c'est-à-dire tant que l'actionneur hydraulique (non représenté) ne consomme pas de fluide hydraulique haute pression et que donc il n'est pas actionné, le piston différentiel 18 est immobilisé du fait de l'augmentation de la pression dans première chambre haute pression 28a et le dispositif d'amplification de pression 10 ne consomme par conséquent aucune énergie.However, as long as no flow appears in the main outlet pipe 74, that is to say as long as the hydraulic actuator (not shown) does not consume high pressure hydraulic fluid and therefore it is not not actuated, the differential piston 18 is immobilized due to the increase of the pressure in the first high pressure chamber 28a and the pressure amplification device 10 therefore consumes no energy.

Lorsque un débit apparaît dans la conduite principale de sortie 74, c'est-à-dire lorsque l'actionneur hydraulique consomme du fluide hydraulique, une légère chute de pression dans la première chambre haute pression 28a apparaît, ce qui, sous l'effet de la pression dans la première chambre basse pression 22a, engendre le déplacement du piston différentiel 18 vers la droite de la figure 1, comme cela est indiqué par la flèche Fa sur cette figure 1, ce mouvement du piston différentiel 18 tendant à maintenir la pression PHP_max dans la première chambre haute pression 28a, tandis que la seconde chambre basse pression 22b se vide.When a flow occurs in the main outlet line 74, that is to say when the hydraulic actuator consumes hydraulic fluid, a slight pressure drop in the first high pressure chamber 28a appears, which, under the effect the pressure in the first low-pressure chamber 22a causes the differential piston 18 to move to the right of FIG. 1, as indicated by the arrow F 0 in this FIG. 1, this movement of the differential piston 18 tending to maintain the pressure P HP_max in the first high pressure chamber 28a, while the second low pressure chamber 22b empties.

Le déplacement du piston différentiel 18 engendre une dépression dans la seconde chambre haute pression 28b, ce qui provoque l'ouverture du second clapet anti-retour d'alimentation 80b et l'aspiration du fluide hydraulique depuis la source d'alimentation 82 en fluide hydraulique pour les chambres haute pression 28a, 28b, lorsque la pression dans la seconde chambre haute pression 28b devient inférieure à la pression de la source d'alimentation 82. La seconde chambre hydraulique haute pression 28b se remplit donc sensiblement en même temps que la première chambre hydraulique basse pression 28a se vide. On peut noter que l'alimentation de la chambre haute pression 28b est facilitée si la source d'alimentation 82 est sous pression.The displacement of the differential piston 18 generates a depression in the second high pressure chamber 28b, which causes the opening of the second supply check valve 80b and the aspiration of the hydraulic fluid from the supply source 82 into hydraulic fluid. for the high-pressure chambers 28a, 28b, when the pressure in the second high-pressure chamber 28b becomes lower than the pressure of the supply source 82. The second high-pressure hydraulic chamber 28b thus fills substantially at the same time as the first chamber Low pressure hydraulic 28a is empty. It may be noted that the supply of the high pressure chamber 28b is facilitated if the supply source 82 is under pressure.

A l'approche de la position de fin de course du piston différentiel 18 dans la direction de la flèche Fa, le piston différentiel 18 entre en contact avec le premier doigt de commande 56a puis l'entraîne vers la droite de la figure 1. Le doigt de commande 56a étant monté rigidement sur le support 50, son déplacement provoque la translation, selon l'axe x-x', vers la droite de la figure 1, du support 50. Pendant un premier temps de cette translation, dit « temps de charge », la bille du billage 70 sort du premier renfoncement de commutation 66a et le billage 70 est comprimé par glissement de la bille sur une première face de la dent 68. Durant ce temps de charge du billage de commutation 70, le tiroir 38 du distributeur 34 reste immobile grâce au jeu 64b qui empêche la seconde saillie de commande 60b du support 50 d'entraîner le tiroir 34 vers la droite de la figure 1. Le billage de commutation 70 est dimensionné de telle sorte qu'à partir du moment où ce billage de commutation 70 passe dans un temps de décharge, atteint lorsque la bille du billage 70 dépasse la pointe de la dent 68, point à partir duquel ce billage de commutation 70 se détend pour faire rentrer la bille du billage 70 dans le second renfoncement de commutation 66b, l'énergie restituée par ce billage de commutation 70 est suffisante pour vaincre le billage de maintien en position 48 du tiroir de commande 38 du distributeur 34.On approaching the end-of-travel position of the differential piston 18 in the direction of arrow F0, the differential piston 18 comes into contact with the first control finger 56a and then drives it towards the right of FIG. control finger 56a being rigidly mounted on the support 50, its displacement causes the translation, along the x-x 'axis, to the right of FIG. 1, of the support 50. During a first stage of this translation, referred to as "time the logging ball 70 exits the first switching recess 66a and the blasting 70 is compressed by sliding the ball on a first face of the tooth 68. During this charging time of the switching blasting 70, the slide 38 the distributor 34 remains stationary thanks to the clearance 64b which prevents the second control projection 60b of the support 50 from driving the slide 34 to the right of FIG. 1. The switching projection 70 is dimensioned so that from the moment where this comm billing The auger 70 passes through a discharge time, reached when the log ball 70 extends beyond the tip of the tooth 68, at which point this switching balloon 70 expands to retract the log ball 70 into the second switch recess 66b. , the energy restored by this switching shot 70 is sufficient to overcome the maintaining shot in position 48 of the control spool 38 of the distributor 34.

Grâce au billage de commutation 70, associé au jeu 64, le tiroir de commande a un fonctionnement bistable, échappant à d'éventuels équilibres de pression au niveau du piston différentiel 18 qui auraient pour effet de bloquer le mouvement du piston différentiel 18 et donc également le tiroir de commande 38.Thanks to the switching jet 70, associated with the game 64, the control spool has a bistable operation, escaping any pressure equilibrium at the differential piston 18 which would have the effect of blocking the movement of the differential piston 18 and therefore also the control spool 38.

Ainsi, le tiroir 38 du distributeur 34 atteint sa seconde position de commande représentée sur la figure 2, poussé par la seconde saillie de commande 60b jusqu'à ce que le billage de maintien en position 48 pénètre dans le second renfoncement de maintien en position 44b.Thus, the drawer 38 of the dispenser 34 reaches its second control position shown in FIG. 2, pushed by the second control projection 60b until the holding beam in position 48 enters the second holding recess in position 44b. .

Lors de cette commutation de la position de commande du tiroir de commande 38, la première entrée de commande 40a du distributeur 34 est obturée, tandis que la seconde entrée de commande 40b du distributeur 34 est mise en communication de fluide avec la seconde sortie de commande 42b du distributeur 34 et que la seconde sortie de commande 42a du distributeur 34 est mise en communication de fluide avec la sortie de décharge 44 du distributeur. On coupe ainsi l'alimentation de la première chambre basse pression 22a, on alimente au contraire la seconde chambre basse pression 22b et on permet l'évacuation du fluide hydraulique de commande contenu dans la première chambre basse pression 22a.Upon this switching of the control slide control position 38, the first control input 40a of the valve 34 is closed, while the second control input 40b of the valve 34 is brought into fluid communication with the second control output. 42b of the distributor 34 and that the second control output 42a of the distributor 34 is in fluid communication with the discharge outlet 44 of the distributor. Thus, the supply of the first low-pressure chamber 22a is cut off, the second low-pressure chamber 22b is fed to the contrary and the control hydraulic fluid contained in the first low-pressure chamber 22a is evacuated.

Sous l'effet de cette nouvelle configuration correspondant à la seconde position de commande du tiroir de commande 38, le mouvement du piston différentiel 18 est inversé, le piston différentiel 18 se déplaçant alors vers la gauche de la figure 2, comme cela est indiqué par la flèche Fb sur cette figure 2.Under the effect of this new configuration corresponding to the second control position of the control spool 38, the movement of the differential piston 18 is reversed, the differential piston 18 then moving to the left of FIG. 2, as indicated by FIG. the arrow Fb in this figure 2.

Le déplacement du piston différentiel 18 dans la direction de la flèche Fb engendre une dépression dans la première chambre haute pression 28a, ce qui provoque l'ouverture du premier clapet anti-retour d'alimentation 80a et l'aspiration du fluide hydraulique basse pression depuis la source d'alimentation 82, lorsque la pression dans la première chambre haute pression 28a devient inférieure à la pression de la source d'alimentation 82. La première chambre hydraulique haute pression 28a se remplit donc sensiblement en même temps que la seconde chambre hydraulique basse pression 28b se vide.The displacement of the differential piston 18 in the direction of the arrow Fb generates a depression in the first high pressure chamber 28a, which causes the opening of the first supply check valve 80a and the suction of the low pressure hydraulic fluid from the supply source 82, when the pressure in the first high pressure chamber 28a becomes lower than the pressure of the supply source 82. The first high pressure hydraulic chamber 28a thus fills substantially at the same time as the second low hydraulic chamber pressure 28b is empty.

A l'approche de la position de fin de course du piston différentiel 18 dans la direction de la flèche Fb, le piston différentiel 18 entre en contact avec le second doigt de commande 56b puis l'entraîne vers la gauche de la figure 2. Le second doigt de commande 56b étant monté rigidement sur le support 50, son déplacement provoque la translation, selon l'axe x-x', vers la gauche de la figure 2, du support 50. Pendant un temps de charge au cours de cette translation, la bille du billage 70 sort du second renfoncement de commutation 66b et le billage 70 est comprimé par glissement de la bille sur le seconde face de la dent 68. Durant ce temps de charge du billage de commutation 70, le tiroir 38 du distributeur 34 reste immobile grâce au jeu 64a qui empêche la première saillie de commande 60a du support 50 d'entraîner le tiroir 34 vers la gauche de la figure 2. Le billage de commutation 70, dimensionné de telle sorte que l'énergie restituée par ce billage de commutation 70 durant le temps de décharge soit suffisante pour vaincre le billage de maintien en position 48 du tiroir de commande 38 du distributeur 34, ramène le tiroir 38 du distributeur 34 dans sa première position de commande.On approaching the end position of the differential piston 18 in the direction of the arrow Fb, the differential piston 18 comes into contact with the second control finger 56b and then drives it to the left of FIG. second control finger 56b being rigidly mounted on the support 50, its displacement causes the translation, along the x-x 'axis, to the left of Figure 2, the support 50. During a load time during this translation the log ball 70 exits the second switch recess 66b and the log 70 is compressed by sliding the ball on the second face of the tooth 68. During this charging time of the switching shot 70, the slide 38 of the dispenser 34 remains stationary thanks to the clearance 64a which prevents the first control projection 60a of the support 50 from driving the slide 34 towards the left of FIG. 2. The switching projection 70, dimensioned so that the energy restored by this projection of switching 70 d the time of discharge is sufficient to overcome the holding mantle in position 48 of the control spool 38 of the dispenser 34, returns the spool 38 of the dispenser 34 to its first control position.

Dès lors, tant qu'il y a un débit de fluide hydraulique dans la conduite principale de sortie 74, c'est-à-dire tant que l'actionneur hydraulique consomme du fluide hydraulique ou tant que la pression dans la conduite principale de sortie 74 est inférieure à la pression PHP_max, le piston différentiel 18 effectue des allers-retours dans le vérin à piston différentiel 12.Therefore, as long as there is a flow of hydraulic fluid in the main outlet pipe 74, that is to say as long as the hydraulic actuator consumes hydraulic fluid or as the pressure in the main outlet pipe 74 is lower than the pressure P HP_max , the differential piston 18 travels back and forth in the differential piston cylinder 12.

Il est à noter que le dispositif selon l'invention peut être réalisé de manière uniquement mécanique et hydraulique, c'est-à-dire qu'il ne comporte par exemple aucun élément électronique, ce qui facilite son intégration dans le moteur.It should be noted that the device according to the invention can be made solely mechanically and hydraulically, that is to say that it comprises for example no electronic element, which facilitates its integration into the engine.

Il est remarquable que l'alimentation des chambres haute pression prélève uniquement l'énergie utile pour la mise en oeuvre de l'actionneur hydraulique et compenser les fuites éventuelles.It is remarkable that the supply of the high pressure chambers takes only the useful energy for the implementation of the hydraulic actuator and compensate for any leaks.

Par ailleurs, le dispositif d'amplification de pression selon l'invention fournit, au rendement près, l'énergie qu'il reçoit. La pression étant amplifiée, le débit restitué est plus faible que le débit prélevé. De plus, le débit prélevé n'est généralement pas constant mais dépend au contraire du régime moteur. Pour palier à ces contraintes, le dispositif d'amplification de pression selon l'invention peut alimenter un actionneur hydraulique au travers d'un accumulateur hydraulique. Cet accumulateur doit avoir la capacité de fournir le débit nécessaire pour un actionnement complet de l'actionneur hydraulique garantissant ainsi un temps de réponse optimal de l'actionneur.Moreover, the pressure amplification device according to the invention provides, at the efficiency, the energy it receives. The pressure being amplified, the returned flow is lower than the flow taken. In addition, the flow taken is generally not constant but instead depends on the engine speed. To overcome these constraints, the pressure amplification device according to the invention can supply a hydraulic actuator through a hydraulic accumulator. This accumulator must have the capacity to provide the necessary flow for a complete actuation of the hydraulic actuator thus ensuring an optimal response time of the actuator.

L'invention ne se réduit pas au seul exemple de mode de réalisation décrit ici à titre d'exemple illustratif et non limitatif et de nombreux modes de réalisation sont possibles sans sortir du cadre de l'invention.The invention is not limited to the only exemplary embodiment described here by way of illustrative and nonlimiting example and many embodiments are possible without departing from the scope of the invention.

On peut par exemple envisager un dispositif ne comprenant qu'une chambre haute pression au lieu de deux chambres haute pression comme cela a été présenté ci-avant, ou un dispositif où les têtes haute pression et la tête basse pression ne seraient pas coaxiales ou encore un dispositif où les têtes haute pression ne seraient pas réalisées directement sur la tête basse pression mais uniquement couplées à cette tête basse pression (via un arbre par exemple).For example, it is possible to envisage a device comprising only a high pressure chamber instead of two high pressure chambers as has been presented above, or a device in which the high pressure heads and the low pressure head would not be coaxial or else a device where the high pressure heads would not be made directly on the low pressure head but only coupled to this low pressure head (via a shaft for example).

On peut également envisager que le billage de commutation soit solidaire du support et que les renfoncements de commutation et la dent qui coopèrent avec ce billage soient alors solidaires du bâti. Par ailleurs, cette dent peut avoir une forme moins régulière que la forme d'un triangle. De préférence, cette dent présente un sommet en pointe. De préférence encore, cette dent est sensiblement symétrique. Le dispositif de billage de commutation, c'est-à-dire le dispositif comportant une bille montée sur un ressort, peut également être remplacé par tout moyen d'appui élastique apte à coopérer avec les renfoncements de commutation et la dent, comme, à titre d'exemple illustratif et non limitatif, une languette métallique élastique.It is also conceivable that the switching shotage is integral with the support and that the switching recesses and the tooth cooperating with this projection are then integral with the frame. Moreover, this tooth may have a less regular shape than the shape of a triangle. Preferably, this tooth has a peak tip. More preferably, this tooth is substantially symmetrical. The switchgearing device, that is to say the device comprising a ball mounted on a spring, may also be replaced by any resilient support means adapted to cooperate with the switching recesses and the tooth, as, for example, illustrative and nonlimiting example, an elastic metal tongue.

De même, on peut concevoir un dispositif d'amplification de pression où le billage de maintien en position du tiroir est solidaire du tiroir de commande et où les renfoncements de maintien en position sont réalisés à l'intérieur de la douille du distributeur. Là encore, le billage de maintien en position peut être remplacé par tout moyen bistable de maintien en position, comme, à titre d'exemple illustratif et non limitatif, une lame métallique élastique.Similarly, one can design a pressure amplification device where the holding shot in the drawer position is integral with the control spool and where the holding recesses in position are formed inside the bushing of the dispenser. Again, the holding shot in position can be replaced by any bistable means for holding in position, such as, by way of illustrative and non-limiting example, an elastic metal blade.

De plus, le distributeur peut également comporter deux sorties de décharge, chacune des sorties de décharge étant apte à être mise en communication de fluide avec une des chambres basse pression du vérin à piston différentiel.In addition, the dispenser may also include two discharge outlets, each of the discharge outlets being adapted to be placed in fluid communication with one of the low pressure chambers of the differential piston cylinder.

Enfin, il est noter que les applications pour un tel dispositif d'amplification de pression sont nombreuses. En effet, le dispositif d'amplification de pression selon l'invention peut être mis en oeuvre avec tout type d'actionneur hydraulique, notamment les actionneurs hydrauliques disposés à l'intérieur d'un moteur thermique, comme, à titre d'exemple illustratif et non limitatif, un actionneur hydraulique de contrôle de la course d'un piston dans un moteur à taux de compression variable.Finally, it should be noted that the applications for such a pressure amplification device are numerous. Indeed, the pressure amplification device according to the invention can be implemented with any type of hydraulic actuator, in particular the hydraulic actuators arranged inside a heat engine, as, for illustrative example and not limiting, a hydraulic actuator for controlling the stroke of a piston in a variable compression ratio engine.

Claims (10)

Dispositif d'amplification de pression (10) pour un actionneur hydraulique situé dans un moteur thermique caractérisé en ce qu'il comporte : - un vérin à piston différentiel (12) comportant un cylindre basse pression (14), au moins un premier cylindre haute pression (16a) dans le prolongement dudit cylindre basse pression (14), et un piston différentiel (18) comprenant une tête basse pression (20), pouvant coulisser de manière étanche dans ledit cylindre basse pression (14) et divisant le volume intérieur du cylindre basse pression (14) en des première (22a) et seconde (22b) chambres basse pression, et une première tête haute pression (24a) entraînée par ladite tête basse pression (20) et montée coulissante dans ledit premier cylindre haute pression (24a) de manière à délimiter avec ledit premier cylindre haute pression (16a) une première chambre haute pression (28a), ladite première chambre haute pression comportant une première entrée de fluide hydraulique basse pression (29a) et une première sortie de fluide hydraulique haute pression (29a), - un distributeur (34) de fluide hydraulique de commande comportant une douille (36) et un tiroir de commande (38) apte à coulisser dans ladite douille (36) entre des première et seconde positions de commande dans lesquelles, ladite première (22a), respectivement seconde (22b), chambre basse pression est en communication de fluide avec une première (40a), respectivement une seconde (40b), entrée de commande du distributeur (34), la seconde (22b), respectivement première (22a), chambre basse pression étant alors isolée de ladite seconde (40b), respectivement première (40a), entrée de commande du distributeur (34) et en communication de fluide avec une sortie de décharge (44) dudit distributeur (34), - des moyens de couplage mécanique dudit tiroir de commande (38) et dudit piston différentiel (18) de manière à commander la commutation de la position dudit tiroir de commande (38) au moyen dudit piston différentiel (18). Pressure amplification device (10) for a hydraulic actuator located in a heat engine characterized in that it comprises: a differential piston cylinder (12) comprising a low pressure cylinder (14), at least a first high pressure cylinder (16a) in the extension of said low pressure cylinder (14), and a differential piston (18) comprising a low head pressure (20), sealingly slidable in said low pressure cylinder (14) and dividing the interior volume of the low pressure cylinder (14) into first (22a) and second (22b) low pressure chambers, and a first head upwards pressure (24a) driven by said low pressure head (20) and slidably mounted in said first high pressure cylinder (24a) so as to define with said first high pressure cylinder (16a) a first high pressure chamber (28a), said first chamber high pressure device comprising a first low pressure hydraulic fluid inlet (29a) and a first high pressure hydraulic fluid outlet (29a), a distributor (34) for hydraulic control fluid comprising a bushing (36) and a control spool (38) slidable in said bushing (36) between first and second control positions in which said first (22a) , respectively second (22b), low pressure chamber is in fluid communication with a first (40a), respectively a second (40b), distributor control input (34), the second (22b), respectively first (22a), low pressure chamber being then isolated from said second (40b), respectively first (40a), distributor control input (34) and in fluid communication with a discharge outlet (44) of said distributor (34), - Mechanical coupling means of said control spool (38) and said differential piston (18) so as to control the switching of the position of said control spool (38) by means of said differential piston (18). Dispositif d'amplification de pression (10) selon la revendication 1, caractérisé en ce que ledit distributeur (34) comporte des moyens bistables de maintien en position dudit tiroir de commande (38) dans lesdites première et seconde position de commande.Pressure amplifying device (10) according to claim 1, characterized in that said distributor (34) comprises bistable means for holding said control spool (38) in position in said first and second control positions. Dispositif d'amplification de pression (10) selon la revendication 2, caractérisé en ce que lesdits moyens bistables de maintien en position dudit tiroir de commande (38) comprennent des premier (46a) et second (46b) renfoncements de maintien en position ménagés sur ledit tiroir de commande (38), et un billage de maintien en position (48), solidaire de ladite douille (36) et coopérant avec lesdits renfoncements de maintien en position (46a, 46b).Pressure amplification device (10) according to claim 2, characterized in that said bistable means for holding in position said drawer of control (38) includes first (46a) and second (46b) position-holding recesses provided on said control spool (38), and a position-keeping blast (48) integral with said spool (36) and cooperating with with said position-retaining recesses (46a, 46b). Dispositif d'amplification de pression (10) selon l'une des revendications 1 à 3, caractérisé en ce que lesdits moyens de couplage mécanique comportent un support (54) comportant des premier (56a) et second (56b) doigts de commande pénétrant dans ledit vérin à piston différentiel (12) de manière à être poussés par ledit piston différentiel (18) à l'approche de la première, respectivement de la seconde, position de fin de course dudit piston (18), et des première (60a) et seconde (60b) saillies de commande aptes à pousser, sous l'effet du déplacement du premier (56a), respectivement du second (56b), doigt de commande, ledit tiroir de commande (38) de manière à amener ledit tiroir (38) depuis une position de commande jusqu'à l'autre position de commande.Pressure amplification device (10) according to one of claims 1 to 3, characterized in that said mechanical coupling means comprise a support (54) having first (56a) and second (56b) control fingers penetrating into said differential piston cylinder (12) so as to be urged by said differential piston (18) towards the first and second end position of said piston (18) and the first (60a) and second (60b) control projections adapted to push, under the effect of the displacement of the first (56a), respectively the second (56b), control finger, said control spool (38) so as to bring said drawer (38 ) from one control position to the other control position. Dispositif d'amplification de pression (10) selon la revendication 4, caractérisé en ce qu'il comporte en outre des moyens de commutation rapide de la position de commande dudit tiroir (34).Pressure amplification device (10) according to claim 4, characterized in that it further comprises means for rapid switching of the control position of said drawer (34). Dispositif d'amplification de pression selon la revendication 5, caractérisé en ce que lesdits moyens de commutation rapide comportent une dent (68) ménagée sur ledit support (54) et des moyens d'appui élastiques (70) coopérant avec ladite dent (68), de manière à ce qu'une translation dudit support (54) sous l'effet du déplacement d'un desdits doigts de commande (56a, 56b) provoque, durant un temps de charge, une compression desdits moyens d'appui élastiques (70), ledit support (54) étant ensuite, durant un temps de décharge, poussé par le glissement desdits moyens élastiques (70) sur ladite dent (68), de manière à pousser ledit tiroir de commande (38) au moyen de ladite première (60a), respectivement seconde (60b), saillie de commande depuis la première, respectivement seconde, position de commande dudit tiroir (38) jusqu'à la seconde, respectivement la première, position de commande dudit tiroir (38).Pressure amplification device according to claim 5, characterized in that said fast switching means comprise a tooth (68) provided on said support (54) and resilient support means (70) cooperating with said tooth (68) , so that a translation of said support (54) under the effect of the displacement of one of said control fingers (56a, 56b) causes, during a charging time, a compression of said elastic bearing means (70 ), said support (54) being then, during a discharge time, pushed by the sliding of said elastic means (70) on said tooth (68), so as to push said control spool (38) by means of said first ( 60a), respectively second (60b), control projection from the first, respectively second, control position of said drawer (38) to the second, respectively the first, control position of said drawer (38). Dispositif d'amplification de pression (10) selon la revendications 6, caractérisé en ce que, ladite première (60a), respectivement seconde (60b), saillie de commande étant en contact avec ladite première (62a), respectivement seconde (62b), extrémité dudit tiroir de commande (38), la seconde (60b), respectivement première (60a), saillie de commande est espacée de ladite seconde (62b), respectivement première (62a), extrémité dudit tiroir de commande (38) au moyen d'un jeu (64a, 64b), de manière à ce que, durant ledit temps de charge desdits moyens d'appui élastiques (70), ledit piston différentiel (18) puisse entraîner ledit support (50) sans déplacer ledit tiroir de commande (38) et à ce que, durant ledit temps de décharge desdits moyens d'appui élastiques (70), le coulissement dudit support (50) entraîne le coulissement dudit tiroir de commande (38).A pressure amplification device (10) according to claim 6, characterized in that said first (60a), respectively second (60b), control projection being in contact with said first (62a), respectively second (62b), end of said control spool (38), the second (60b), respectively first (60a), control projection is spaced from said second (62b), respectively first (62a), end of said control spool (38) by means of a set (64a, 64b) so that, during said load time of said resilient support means (70), said differential piston (18) can drive said support (50) without moving said control spool (50) (38) and during said discharge time of said resilient support means (70), sliding of said support (50) causes said control spool (38) to slide. Dispositif d'amplification de pression selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit vérin à piston différentiel (12) comporte en outre un second cylindre haute pression (16b) réalisé dans le prolongement dudit cylindre basse pression (14), opposé audit premier cylindre haute pression (16a), et une seconde tête haute pression (24b) dans le prolongement de ladite tête basse pression (20), entraînée par ladite tête basse pression (20) et montée coulissante dans ledit second cylindre haute pression (16b) de manière à délimiter avec ledit second cylindre haute pression (16b) une seconde chambre haute pression (28b), ladite seconde chambre haute pression (28b) comportant une seconde entrée de fluide hydraulique basse pression (29b) et une seconde sortie de fluide hydraulique haute pression (29b).Pressure amplification device according to any one of the preceding claims, characterized in that said differential piston cylinder (12) further comprises a second high pressure cylinder (16b) formed in the extension of said low pressure cylinder (14), opposite said first high pressure cylinder (16a), and a second high pressure head (24b) in the extension of said low pressure head (20), driven by said low pressure head (20) and slidably mounted in said second high pressure cylinder ( 16b) for defining with said second high pressure cylinder (16b) a second high pressure chamber (28b), said second high pressure chamber (28b) having a second low pressure hydraulic fluid inlet (29b) and a second fluid outlet hydraulic high pressure (29b). Dispositif d'amplification de pression selon l'une quelconque des revendications précédentes, caractérisé en ce que des première (72a) et seconde (72b) conduites secondaires de sortie débouchant respectivement dans lesdites première (28a) et seconde (28b) chambres haute pression, et pourvues d'un premier (76a), respectivement d'un second (76b), clapet d'anti-retour vers les première (28a) et seconde (28b) chambres haute pression, se rejoignent pour former une conduite principale de sortie (74).Pressure amplification device according to any one of the preceding claims, characterized in that first (72a) and second (72b) secondary outlet ducts opening respectively into said first (28a) and second (28b) high pressure chambers, and provided with a first (76a), respectively a second (76b), non-return valve to the first (28a) and second (28b) high pressure chambers, join to form a main outlet pipe ( 74). Moteur thermique comprenant un actionneur hydraulique et un dispositif d'amplification de pression (10) selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit fluide hydraulique de commande et/ou ledit fluide hydraulique basse pression est de l'huile lubrifiant ledit moteur.A thermal engine comprising a hydraulic actuator and a pressure amplification device (10) according to any one of the preceding claims, characterized in that said hydraulic control fluid and / or said low pressure hydraulic fluid is lubricating oil said engine.
EP06300590A 2005-07-27 2006-06-14 Pressure amplification device for a hydraulic actuator in an internal combustion engine and engine incorporating such device Withdrawn EP1748194A1 (en)

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FR0508007A FR2889265A1 (en) 2005-07-27 2005-07-27 PRESSURE AMPLIFICATION DEVICE FOR A HYDRAULIC ACTUATOR LOCATED IN A THERMAL MOTOR AND MOTOR INCORPORATING SUCH A DEVICE

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Cited By (5)

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WO2011051661A1 (en) * 2009-10-28 2011-05-05 Keith Donald Woodford Pressure control system
NL2005668C2 (en) * 2010-11-11 2012-05-14 Arif Yilmaz DEVICE FOR COMPRESSING A FLUID FOR ENERGY GENERATION.
CN105626600A (en) * 2016-03-04 2016-06-01 中国矿业大学 Successive pressurization type hydraulic pressurizer
CN108571480A (en) * 2018-05-18 2018-09-25 宁波真格液压科技有限公司 A kind of hydraulic booster pump
CN108591138A (en) * 2018-05-04 2018-09-28 东莞海特帕沃液压科技有限公司 A kind of four plunger hydraulic boosters

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FR3009849B1 (en) 2013-08-20 2016-03-11 Vianney Rabhi REVERSIBLE HYDRAULIC PRESSURE CONVERTER WITH TUBULAR VALVES
US9695840B2 (en) 2013-08-20 2017-07-04 Vianney Rabhi Reversible hydraulic pressure converter employing tubular valves

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011051661A1 (en) * 2009-10-28 2011-05-05 Keith Donald Woodford Pressure control system
NL2005668C2 (en) * 2010-11-11 2012-05-14 Arif Yilmaz DEVICE FOR COMPRESSING A FLUID FOR ENERGY GENERATION.
CN105626600A (en) * 2016-03-04 2016-06-01 中国矿业大学 Successive pressurization type hydraulic pressurizer
CN108591138A (en) * 2018-05-04 2018-09-28 东莞海特帕沃液压科技有限公司 A kind of four plunger hydraulic boosters
CN108571480A (en) * 2018-05-18 2018-09-25 宁波真格液压科技有限公司 A kind of hydraulic booster pump

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