EP0500419B1 - Proportional valve and control system with a plurality of actuators having each such a valve - Google Patents

Proportional valve and control system with a plurality of actuators having each such a valve Download PDF

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Publication number
EP0500419B1
EP0500419B1 EP92400358A EP92400358A EP0500419B1 EP 0500419 B1 EP0500419 B1 EP 0500419B1 EP 92400358 A EP92400358 A EP 92400358A EP 92400358 A EP92400358 A EP 92400358A EP 0500419 B1 EP0500419 B1 EP 0500419B1
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EP
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Prior art keywords
slide valve
pressure
compensator slide
compensator
piston
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EP92400358A
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German (de)
French (fr)
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EP0500419A1 (en
Inventor
Louis Marcon
André Rousset
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Marrel SA
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Marrel SA
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Classifications

    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/0416—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor with means or adapted for load sensing
    • F15B13/0417—Load sensing elements; Internal fluid connections therefor; Anti-saturation or pressure-compensation valves
    • 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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F15B2211/3053—In combination with a pressure compensating valve
    • F15B2211/30535—In combination with a pressure compensating valve the pressure compensating valve is arranged between pressure source and directional control valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5159—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a return line
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle valves
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders

Definitions

  • the invention relates to proportional hydraulic distributors.
  • distributors are devices that are available between a flow generation and a receiver to control the operation of the receiver by adapting the way it is connected to the flow generation.
  • Proportional type distributors include not only a controlled drawer whose position determines the section of a constriction, but also an automatic compensating drawer to maintain constant the pressure difference between the upstream and downstream of this constriction, so that at a given position of the controlled slide corresponds to a given flow of fluid. Consequently, when a receiver is controlled with a proportional distributor, its operating speed is fixed by the position of the controlled drawer, independently of the load that the receiver supports.
  • the circuit includes load detection means called "load-sensing" which bring the pressure of the most loaded receiver towards the generation of flow. , to which pressure responds the generation of flow by producing an operating pressure equal to the load-sensing pressure plus a constant; and secondly, where the distributor has a compensating drawer which automatically takes a position where it produces upstream of the throttle of the controlled drawer a second throttling of appropriate section, the compensating drawer comprising two opposite active surfaces, a first surface subjected to pressure upstream of the first throttle to urge the drawer in the direction of closing, and a second surface subjected to pressure downstream of the first throttle to urge the compensating drawer in the direction of opening.
  • load detection means called "load-sensing" which bring the pressure of the most loaded receiver towards the generation of flow.
  • pressure responds the generation of flow by producing an operating pressure equal to the load-sensing pressure plus a constant
  • the distributor has a compensating drawer which automatically takes a position where it produces upstream of the throttle of the controlled drawer a second
  • the invention proposes that said additional means are provided so that the compensating drawer is further urged in the closing direction by a substantially constant force, said first and second active surfaces of the compensating drawer , and said complementary means being dimensioned so that in service the pressure difference between the upstream and downstream of the first throttle, depends on the difference between the service and load-sensing pressures, according to a linear function with strictly coefficient positive and strictly negative constant.
  • the receivers each slow down in the event of excessive demand for flow, the speed ratios between the receivers each being preserved.
  • proportional distributors according to the invention are therefore particularly advantageous from the safety point of view, for example in public works vehicles where they make it possible to completely avoid the risk of accident in the event of excessive demand for flow, since the various cylinders can no longer escape the driver's control as before.
  • said first and second active surfaces of the compensating slide have a similar dimensioning
  • said first active surfaces of the first and second pistons have a similar dimensioning
  • said second active surfaces of the first and second pistons have a similar dimensioning
  • each distributor has a compensating drawer operating according to the same linear function.
  • At least one of the distributors has a compensating drawer operating according to a different linear function.
  • the distributor 70 illustrated in FIG. 1 is similar to that described in French patent FR-B-2,562,632, with the exception of its pressure compensating device.
  • stator block 1 in the bore 2 of which slides a cylindrical controlled drawer 3.
  • switching of the hydraulic circuits is effected by displacement of the grooves of the drawer 3 in front of the lights of the stator.
  • the drawer 3 is provided with a spring return device of known type, comprising a helical spring 4, compressed between the shoulders 5 and 6 of two rings 7 and 8, trapped between two shoulders of the end 9 of the drawer 3, around which they can slide.
  • a spring return device of known type, comprising a helical spring 4, compressed between the shoulders 5 and 6 of two rings 7 and 8, trapped between two shoulders of the end 9 of the drawer 3, around which they can slide.
  • the drawer 3 is spontaneously returned to a neutral rest position, while it is pushed to the right (FIG. 1) when a pilot pressure is sent into an opening 10 of the fixed cap 61.
  • a pilot pressure is sent opposite, in an opening 11 of the cap 62 at its other end.
  • the three-position slide 3 is used to control a double-acting hydraulic cylinder 12.
  • one of the sections of the cylinder 12 is connected to a first channel use 13 of the stator 1, while the opposite section of the jack 12 is connected to a second use pipe 14 of the stator 1.
  • the distributor receives in an annular chamber 15, the pressure sent by a generation of flow 71.
  • the supply chamber 15 surrounds a cylindrical compensating slide 16 provided with a radial bore 22, communicating with a blind axial bore 23.
  • the latter opens onto a seat capable of being closed off or unmasked by a ball 24 whose return spring 25 is compressed inside the compensating drawer 16.
  • the chamber containing the ball 24 and the spring 25 opens through a lateral opening 26 in an annular chamber 27 surrounding the central part of the controlled drawer 3.
  • the controlled slide 3 has an axial internal housing, 28 on the left, 29 on the right.
  • the housing 28 communicates with the outside of the drawer by two radial bores referenced respectively 30 and 31. Likewise, the housing 29 opens onto two radial bores 32 and 33.
  • the bore 30 faces a solid part 34 of the stator which closes it, between two annular chambers 35 and 36.
  • the chamber 35 communicates with the first use pipe 13, while the chamber 36 is connected to the return circuit.
  • the bore 32 is closed at rest, by a solid part 37, located between two annular chambers 38 and 39.
  • the chamber 38 communicates with the second use pipe 14, while the chamber 39 is connected to the return circuit .
  • the stator defines, in the bore, a solid part 40, in front of which is capable of moving a groove 41 of the drawer 3.
  • annular stator chamber 42 Around the drawer 3, in the zone situated around the bore 31 when the drawer 3 is pushed to the right (FIG. 1), there is an annular stator chamber 42.
  • the drawer 3 has a groove 43 movable in front of a solid part 44 of the stator.
  • a solid part 44 of the stator Around passage 33 when drawer 3 is pushed to the left, there is an annular stator chamber 45.
  • the two chambers 42 and 45 are connected by a pipe 46 called the load sensing pipe.
  • a first booster valve 52 is mounted in parallel on the first use pipe 13.
  • a booster valve 53 is mounted in parallel on the second user pipe 14. Behind the valves 52 and 53, is finds a chamber 54 connected to the oil return circuit.
  • a pressure relief valve, respectively 55 and 56, is provided on the side of each of the use pipes 13, 14, which can thus flow into the return chambers, respectively 36, 39.
  • the chambers 27, 35 and 38 are closed, so that the jack 12 is immobilized while no flow passes through the distributor.
  • the pipe 46 communicates through the grooves 41 and 43 respectively with the chamber 36 and the chamber 39, that is to say that it is connected to the return circuit.
  • the slide 3 slides to the right with an amplitude determined by the value of the pilot pressure, which is balanced with the opposing thrust of the spring 4, more or less compressed.
  • the supply pressure of the chamber 27 is sent into the line 13 through the groove 49 and the chamber 35, while the line 14 communicates with the return chamber 39 through the groove 51.
  • Each of the grooves 49 and 51 determines a constriction whose cross section is determined by the position of the drawer 3.
  • the pipe 46 communicates on the left with the pipe 13 through the passages 31, 28 and 30, while on the right it is closed. The pressure downstream of the throttle provided by the groove 49 is thus transmitted to the pipe 46.
  • the slide 3 slides to the left to a position determined by the amplitude of the pilot pressure.
  • the supply pressure of the chamber 27 is sent into the line 14 passing through the groove 50 and the chamber 38, while the line 13 communicates with the return chamber 36 through the groove 48.
  • Each of the grooves 48 and 50 determines a constriction, the section of which is determined by the position of the drawer 3.
  • the pipe 46 communicates on the right with the pipe 14 by the holes 33, 29 and 32, while on the left it is closed. The pressure downstream of the throttle provided by the groove 50 is thus transmitted to the pipe 46.
  • the circuit selector 99 (also called OR function) has one of its inputs which communicates with the pipe 46 by a channel 72, and its other input which communicates with a channel 73 connected to the output pipe of the circuit selector d '' a similar distributor.
  • the pressure in the line 46 is the highest, so that the circuit selector 99 adopts the illustrated position where it transmits by its output to the line 74 the operating pressure of the cylinder 12, which is the pressure of highest use of all receivers that feeds the flow generation 71. More generally, as is clearly seen in FIG. 2, it is always the pressure of the most loaded receiver which is applied to the pipe 74, this pressure known as load sensing being transmitted to the generation of flow 71 which produces a working pressure normally equal to the load sensing pressure plus a constant.
  • the compensating slide 16 also called a balance, is movable in a bore 80 of the stator 1 and has around the channel 22 a groove 81 which produces, depending on the position of the slide, a more or less significant constriction upstream of the constriction provided by the drawer 3 on the supply line of the jack 12, according to the position taken by the drawer 16.
  • This comprises two opposite active surfaces, on the left a surface 82 subjected to the pressure upstream of the throttle provided by the slide 3, and on the right a surface 83 subjected to the pressure prevailing in the pipe 46, that is to say that is to say the operating pressure of the jack 12.
  • This slide 16 is biased on the left in the direction of closing the throttle that it produces, and on the right in the direction of opening.
  • each piston 84 or 85 comes into contact with the compensating slide by a stud, and slides in a cylinder, respectively 86 or 87, screwed into the stator 1 coaxially with the bore 80, each cylinder being open on the inside and closed on the side. outside, the cylinder 86 sealingly crossing the pipe 46.
  • the pistons 84 and 85 are similar and each have L-shaped passages which allow the chamber located between the piston and the bottom of the cylinder to communicate with the pipe 89 or 90, respectively.
  • Line 89 is connected to the load sensing line of the flow generation, so that it is brought to the load sensing pressure, while the pipe 90 is connected to the service line so that it is brought to the service pressure.
  • the pistons 84 and 85 each have two opposite active surfaces, one of which (91 for the cylinder 84 and 92 for the cylinder 85) is opposite the corresponding active surface of the drawer 16 (respectively 82 and 83), and subjected to the same pressure.
  • the second active surface 93 of the piston 84 is subjected to the load sensing pressure, and the second active surface 94 of the piston 85 is subjected to the operating pressure.
  • a spring 95 applies the piston 84 against the drawer 16.
  • the effective value of surfaces 82 and 83 is similar (denoted S1), the same is true for the effective value of surfaces 91 and 92 (denoted S2), and also the same for the effective value of surfaces 93 and 94 (denoted S3 ).
  • conduits 89 and and 90 pass through the entire distributor 70, so that the possibility remains of making all the connections between distributors, by simply joining these latter end-to-end.
  • FIG. 2 schematically shows the distributor 70 attached to a similar distributor 70 ', all the elements relating to the latter bearing the same reference as above but assigned an index premium.
  • the distributor furthest from the pump, here 70 ′ does not receive a circuit selector with an input connected to the reservoir, but has its channel 74 directly connected to the pipe 46.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)

Description

L'invention a trait aux distributeurs hydrauliques proportionnels.The invention relates to proportional hydraulic distributors.

On sait que les distributeurs sont des appareils qu'on dispose entre une génération de débit et un récepteur pour commander le fonctionnement du récepteur en adaptant la façon dont il est connecté à la génération de débit.We know that distributors are devices that are available between a flow generation and a receiver to control the operation of the receiver by adapting the way it is connected to the flow generation.

Les distributeurs du type proportionnel comportent non seulement un tiroir commandé dont la position détermine la section d'un étranglement, mais aussi un tiroir compensateur automatique pour maintenir constante la différence de pression entre l'amont et l'aval de cet étranglement, afin qu'à une position donnée du tiroir commandé corresponde un débit donné de fluide. Par conséquent, lorsqu'un récepteur est commandé avec un distributeur proportionnel, sa vitesse de fonctionnement est fixée par la position du tiroir commandé, indépendamment de la charge que supporte le récepteur.Proportional type distributors include not only a controlled drawer whose position determines the section of a constriction, but also an automatic compensating drawer to maintain constant the pressure difference between the upstream and downstream of this constriction, so that at a given position of the controlled slide corresponds to a given flow of fluid. Consequently, when a receiver is controlled with a proportional distributor, its operating speed is fixed by the position of the controlled drawer, independently of the load that the receiver supports.

Lorsque la génération de débit est utilisée pour alimenter une pluralité de récepteurs à chacun desquels correspond un distributeur proportionnel, il peut arriver que le débit total demandé par les récepteurs excède le débit maximal que la pompe est en mesure de fournir. Les tiroirs compensateurs respectifs ne sont alors plus en mesure de maintenir dans chacun des distributeurs la différence de pression entre l'amont et l'aval de l'étranglement à la constante préfixée, de sorte que les récepteurs les plus chargés ralentissent ou s'arrêtent alors que les moins chargés peuvent continuer à fonctionner.When the generation of flow is used to supply a plurality of receivers to each of which corresponds a proportional distributor, it can happen that the total flow requested by the receivers exceeds the maximum flow that the pump is able to supply. The respective compensating drawers are then no longer able to maintain in each of the distributors the pressure difference between the upstream and downstream of throttling to the prefixed constant, so that the most loaded receivers slow down or stop while the least loaded can continue to operate.

L'invention vise à éviter ces désordres, plus particulièrement dans le cas où, d'une part, le circuit comporte des moyens de détection de charge dits "Load-sensing" qui ramènent vers la génération de débit la pression du récepteur le plus chargé, à laquelle pression répond la génération de débit en produisant une pression de service égale à la pression de load-sensing plus une constante ; et d'autre part, où le distributeur comporte un tiroir compensateur qui prend automatiquement une position où il produit à l'amont de l'étranglement du tiroir commandé un deuxième étranglement de section appropriée, le tiroir compensateur comportant deux surfaces actives opposées, une première surface soumise à la pression en amont du premier étranglement pour solliciter le tiroir dans le sens de la fermeture, et une deuxième surface soumise à la pression en aval du premier étranglement pour solliciter le tiroir compensateur dans le sens de l'ouverture.The invention aims to avoid these disorders, more particularly in the case where, on the one hand, the circuit includes load detection means called "load-sensing" which bring the pressure of the most loaded receiver towards the generation of flow. , to which pressure responds the generation of flow by producing an operating pressure equal to the load-sensing pressure plus a constant; and secondly, where the distributor has a compensating drawer which automatically takes a position where it produces upstream of the throttle of the controlled drawer a second throttling of appropriate section, the compensating drawer comprising two opposite active surfaces, a first surface subjected to pressure upstream of the first throttle to urge the drawer in the direction of closing, and a second surface subjected to pressure downstream of the first throttle to urge the compensating drawer in the direction of opening.

On a déjà proposé dans l'état de la technique selon FR-A-2 548 290, correspondant au distributeur décrit par le préambule de la revendication 1, de prévoir des moyens complémentaires pour que le tiroir compensateur soit en outre sollicité dans le sens de la fermeture par la pression de load-sensing, et dans le sens de l'ouverture par la pression de service de la génération de débit.It has already been proposed in the prior art according to FR-A-2 548 290, corresponding to the dispenser described by the preamble of claim 1, to provide additional means so that the compensating drawer is further stressed in the direction of closing by the load-sensing pressure, and in the opening direction by the operating pressure of the flow generation.

Pour éviter totalement les désordres précités, l'invention propose quant à elle que lesdits moyens complémentaires soient prévus pour que le tiroir compensateur soit en outre sollicité dans le sens de la fermeture par une force sensiblement constante, lesdites première et deuxième surfaces actives du tiroir compensateur, et lesdits moyens complémentaires étant dimensionnés pour qu'en service la différence de pression entre l'amont et l'aval du premier étranglement, dépende de la différence entre les pressions de service et de load-sensing, suivant une fonction linéaire à coefficient strictement positif et à constante strictement négative.To completely avoid the abovementioned disorders, the invention proposes that said additional means are provided so that the compensating drawer is further urged in the closing direction by a substantially constant force, said first and second active surfaces of the compensating drawer , and said complementary means being dimensioned so that in service the pressure difference between the upstream and downstream of the first throttle, depends on the difference between the service and load-sensing pressures, according to a linear function with strictly coefficient positive and strictly negative constant.

Si l'on note Pi la pression en amont de l'étranglement, PUi la pression en aval de l'étranglement, P la pression de service et PU la pression de load sensing, le tiroir compensateur maintient la chute de pression Pi-PUi dans l'étranglement du tiroir commandé, selon l'équation : P i - PU i = k₁(P - PU) - k₂

Figure imgb0001
où k₁ et k₂ sont strictement positifs.If we note P i the pressure upstream of the throttle, PU i the pressure downstream of the throttle, P the operating pressure and PU the load sensing pressure, the compensating slide maintains the pressure drop P i -PU i in the throttle of the ordered drawer, according to the equation: P i - COULD i = k₁ (P - PU) - k₂
Figure imgb0001
 where k₁ and k₂ are strictly positive.

Tant que la génération de débit fonctionne normalement, P-PU reste constant et par conséquent, Pi-PUi reste constant, c'est-à-dire que le tiroir compensateur fonctionne comme dans l'art antérieur, et notamment comme dans le brevet français FR-B-2 562 632 appartenant à la Demanderesse, où le tiroir compensateur est sollicité par un ressort dans le sens de l'ouverture.As long as the flow generation operates normally, P-PU remains constant and therefore P i -PU i remains constant, i.e. the compensating slide operates as in the prior art, and in particular as in the French patent FR-B-2,562,632 belonging to the Applicant, where the compensating drawer is biased by a spring in the direction of opening.

En cas de demande de débit supérieur à celui capable d'être fourni, P-PU devient inférieur à sa valeur normale, de sorte que Pi-PUi va diminuer. Si chacun des distributeurs de l'installation est conforme à l'invention, et qu'ils ont tous été réglés avec le même coefficient k₁ et la même constante -k₂, alors dans chacun des distributeurs Pi- PUi va diminuer de la même quantité. Par conséquent, chaque distributeur se voit appliquer le même taux de réduction de débit (égal à : débit disponible à la génération de débit/débit total demandé).In the event of a demand for flow greater than that capable of being supplied, P-PU becomes less than its normal value, so that P i -PU i will decrease. If each of the distributors of the installation conforms to the invention, and they have all been adjusted with the same coefficient k₁ and the same constant -k₂, then in each of the distributors P i - PU i will decrease by the same quantity. Consequently, each distributor is applied the same rate of reduction of flow (equal to: flow available to the generation of flow / total flow requested).

Ainsi, les récepteurs ralentissent chacun en cas de demande excessive en débit, les rapports de vitesse entre les récepteurs étant chacun conservés.Thus, the receivers each slow down in the event of excessive demand for flow, the speed ratios between the receivers each being preserved.

On notera qu'il est essentiel qu'une force s'applique sur le tiroir compensateur dans le sens de la fermeture, car sans cette force on ne résoudrait que partiellement le problème technique d'éviter les désordres précités en cas de demande excessive en débit.Note that it is essential that a force is applied to the compensating slide in the closing direction, because without this force we would only partially solve the technical problem of avoiding the aforementioned disorders in the event of excessive demand for flow. .

En effet, il arrive un moment où P-PU devient trop petit pour que soit obtenu le Pi-PUi nécessaire dans certains distributeurs, notamment celui correspondant au récepteur le plus chargé. Si l'on continue alors d'alimenter les récepteurs, on se retrouve avec des désordres similaires à ceux rencontrés antérieurement.Indeed, there comes a time when P-PU becomes too small for the P i -PU i required in certain distributors to be obtained, in particular that corresponding to the most loaded receiver. If we then continue to supply the receptors, we end up with disorders similar to those encountered previously.

En revanche, avec la force appliquée dans le sens de la fermeture, il est possible de fermer totalement le tiroir compensateur lorsque P-PU devient trop petit. Par conséquent, avec une batterie de distributeurs proportionnels conformes à l'invention, et en cas de demande excessive en débit, on peut maintenir les rapports de vitesse entre les récepteurs tant que cela reste possible, et arrêter tous les récepteurs lorsque l'excès de demande est trop important pour que tous les rapports soient maintenus.On the other hand, with the force applied in the closing direction, it is possible to completely close the compensating drawer when P-PU becomes too small. Consequently, with a battery of proportional distributors in accordance with the invention, and in the event of excessive demand for flow, it is possible to maintain the speed ratios between the receivers as long as this remains possible, and to stop all the receivers when the excess of demand is too important for all reports to be maintained.

Les distributeurs proportionnels selon l'invention sont donc particulièrement avantageux sur le plan de la sécurité, par exemple dans les engins de travaux publics où ils permettent d'éviter totalement les risques d'accident en cas de demande excessive en débit, puisque les différents vérins ne peuvent plus échapper au contrôle du conducteur comme antérieurement.The proportional distributors according to the invention are therefore particularly advantageous from the safety point of view, for example in public works vehicles where they make it possible to completely avoid the risk of accident in the event of excessive demand for flow, since the various cylinders can no longer escape the driver's control as before.

Selon des caractéristiques préférées de l'invention, lesdits moyens complémentaires comportent :

  • de chaque côté du tiroir compensateur, un piston mobile coaxialement, venant en contact ou solidarisé avec le tiroir compensateur, comportant deux surfaces actives opposées, une première surface qui est en regard d'une desdites surfaces actives du tiroir compensateur et soumise à la même pression, et une deuxième surface soumise, pour un premier piston dont la première surface est en regard de la première surface du tiroir compensateur, à la pression de load sensing, et pour un deuxième piston dont la première surface est en regard de la deuxième surface du tiroir compensateur, à la pression de service ; et,
  • un ressort sollicitant le premier piston vers le tiroir compensateur.
According to preferred characteristics of the invention, said complementary means include:
  • on each side of the compensating drawer, a piston coaxially movable, coming into contact or integral with the compensating drawer, comprising two opposite active surfaces, a first surface which is opposite one of said active surfaces of the compensating drawer and subjected to the same pressure , and a second surface subjected, for a first piston whose first surface is facing the first surface of the compensating slide, at the load sensing pressure, and for a second piston whose first surface is facing the second surface of the compensator drawer, at operating pressure; and,
  • a spring urging the first piston towards the compensating slide.

Ces caractéristiques offrent l'avantage de permettre la mise en oeuvre de l'invention en ne réalisant que des modifications particulièrement simples sur un distributeur antérieur, tel que celui décrit dans le brevet français FR-B-2 562 632 précité.These features offer the advantage of allow the implementation of the invention by making only particularly simple modifications to an anterior distributor, such as that described in the aforementioned French patent FR-B-2,562,632.

De préférence, lesdites première et deuxième surfaces actives du tiroir compensateur ont un dimensionnement similaire, lesdites premières surfaces actives du premier et du deuxième pistons ont un dimensionnement similaire, et lesdites deuxièmes surfaces actives du premier et du deuxième pistons ont un dimensionnement similaire.Preferably, said first and second active surfaces of the compensating slide have a similar dimensioning, said first active surfaces of the first and second pistons have a similar dimensioning, and said second active surfaces of the first and second pistons have a similar dimensioning.

Ainsi, si l'on note S₁ la valeur efficace des première et deuxième surfaces du tiroir compensateur, S₂ la valeur efficace des premières surfaces des pistons, S₃ la valeur efficace des deuxièmes surfaces des pistons, et F la force procurée par le ressort, on obtient : k₁ = S₃/(S₁-S₂) k₂ = F/(S₁-S₂)

Figure imgb0002
   On notera que l'invention vise non seulement le distributeur proportionnel qui vient d'être exposé, mais aussi un ensemble de commande d'une pluralité de récepteurs hydrauliques, comportant pour chaque récepteur un distributeur tel que précédemment exposé.Thus, if we denote S₁ the effective value of the first and second surfaces of the compensating slide, S₂ the effective value of the first surfaces of the pistons, S₃ the effective value of the second surfaces of the pistons, and F the force provided by the spring, we obtains: k₁ = S₃ / (S₁-S₂) k₂ = F / (S₁-S₂)
Figure imgb0002
 It will be noted that the invention relates not only to the proportional distributor which has just been exposed, but also to a control assembly for a plurality of hydraulic receivers, comprising for each receiver a distributor as previously exposed.

De préférence, pour les raisons exposées ci-dessus, chaque distributeur comporte un tiroir compensateur fonctionnant suivant la même fonction linéaire.Preferably, for the reasons explained above, each distributor has a compensating drawer operating according to the same linear function.

En variante, au moins l'un des distributeurs comporte un tiroir compensateur fonctionnant suivant une fonction linéaire différente.As a variant, at least one of the distributors has a compensating drawer operating according to a different linear function.

On peut ainsi établir une priorité de délestage ou de maintien en fonctionnement pour un ou plusieurs récepteur(s).It is thus possible to establish a load shedding or maintenance priority for one or more receivers.

L'exposé de l'invention sera maintenant poursuivi par la description d'un exemple de réalisation, donnée ci-après à titre illustratif et non limitatif, en référence aux dessins annexés, sur lesquels :

  • la figure 1 est une vue schématique en coupe d'un distributeur proportionnel conforme à l'invention ; et
  • la figure 2 est un schéma d'un circuit hydraulique comportant un ensemble de commande avec deux distributeurs similaires à celui montré sur la figure 1, accolés bout-à-bout.
The description of the invention will now be continued with the description of an exemplary embodiment, given below by way of illustration and not limitation, with reference to the appended drawings, in which:
  • Figure 1 is a schematic sectional view of a proportional distributor according to the invention; and
  • Figure 2 is a diagram of a hydraulic circuit comprising a control assembly with two distributors similar to that shown in Figure 1, joined end-to-end.

Le distributeur 70 illustré sur la figure 1 est similaire à celui décrit dans le brevet français FR-B-2 562 632, à l'exception de son dispositif compensateur de pression.The distributor 70 illustrated in FIG. 1 is similar to that described in French patent FR-B-2,562,632, with the exception of its pressure compensating device.

Il comporte un bloc statorique 1, dans l'alésage 2 duquel coulisse un tiroir commandé cylindrique 3. A la manière habituelle, la commutation des circuits hydrauliques s'effectue par déplacement des gorges du tiroir 3 devant des lumières du stator.It comprises a stator block 1, in the bore 2 of which slides a cylindrical controlled drawer 3. In the usual way, the switching of the hydraulic circuits is effected by displacement of the grooves of the drawer 3 in front of the lights of the stator.

A son extrémité gauche, par exemple, le tiroir 3 est pourvu d'un dispositif de rappel par ressort de type connu, comprenant un ressort hélicoïdal 4, comprimé entre les épaulements 5 et 6 de deux bagues 7 et 8, prisonnières entre deux épaulements de l'extrémité 9 du tiroir 3, autour de laquelle elles peuvent coulisser. Ainsi, le tiroir 3 est spontanément rappelé à une position neutre de repos, tandis qu'il est poussé à droite (figure 1) lorsqu'on envoie une pression de pilotage dans une ouverture 10 du chapeau fixe 61. Au contraire, il est poussé vers la gauche lorsqu'une pression de pilotage est envoyée à l'opposé, dans une ouverture 11 du chapeau 62 de son autre extrémité. Dans l'exemple illustré, on a supposé que le tiroir à trois positions 3 est utilisé pour assurer la commande d'un vérin hydraulique double effet 12. Pour cela, l'une des sections du vérin 12 est reliée à un premier canal d'utilisation 13 du stator 1, alors que la section opposée du vérin 12 est reliée à une seconde canalisation d'utilisation 14 du stator 1.At its left end, for example, the drawer 3 is provided with a spring return device of known type, comprising a helical spring 4, compressed between the shoulders 5 and 6 of two rings 7 and 8, trapped between two shoulders of the end 9 of the drawer 3, around which they can slide. Thus, the drawer 3 is spontaneously returned to a neutral rest position, while it is pushed to the right (FIG. 1) when a pilot pressure is sent into an opening 10 of the fixed cap 61. On the contrary, it is pushed to the left when a pilot pressure is sent opposite, in an opening 11 of the cap 62 at its other end. In the example illustrated, it has been assumed that the three-position slide 3 is used to control a double-acting hydraulic cylinder 12. For this, one of the sections of the cylinder 12 is connected to a first channel use 13 of the stator 1, while the opposite section of the jack 12 is connected to a second use pipe 14 of the stator 1.

Le distributeur reçoit dans une chambre annulaire 15, la pression envoyée par une génération de débit 71.The distributor receives in an annular chamber 15, the pressure sent by a generation of flow 71.

La chambre d'alimentation 15 entoure un tiroir compensateur cylindrique 16 pourvu d'un perçage radial 22, communiquant avec un perçage axial borgne 23. Ce dernier débouche sur un siège susceptible d'être obturé ou démasqué par une bille 24 dont le ressort de rappel 25 se trouve comprimé à l'intérieur du tiroir compensateur 16. La chambre contenant la bille 24 et le ressort 25 débouche par une ouverture latérale 26 dans une chambre annulaire 27 entourant la partie centrale du tiroir commandé 3.The supply chamber 15 surrounds a cylindrical compensating slide 16 provided with a radial bore 22, communicating with a blind axial bore 23. The latter opens onto a seat capable of being closed off or unmasked by a ball 24 whose return spring 25 is compressed inside the compensating drawer 16. The chamber containing the ball 24 and the spring 25 opens through a lateral opening 26 in an annular chamber 27 surrounding the central part of the controlled drawer 3.

A chacune de ses deux extrémités, le tiroir commandé 3 comporte un logement intérieur axial, 28 à gauche, 29 à droite.At each of its two ends, the controlled slide 3 has an axial internal housing, 28 on the left, 29 on the right.

Le logement 28 communique avec l'extérieur du tiroir par deux perçages radiaux référencés respectivement 30 et 31. De même, le logement 29 débouche sur deux perçages radiaux 32 et 33.The housing 28 communicates with the outside of the drawer by two radial bores referenced respectively 30 and 31. Likewise, the housing 29 opens onto two radial bores 32 and 33.

Lorsque le tiroir 3 est à sa position neutre de repos, le perçage 30 fait face à une partie pleine 34 du stator qui l'obture, entre deux chambres annulaires 35 et 36. La chambre 35 communique avec la première canalisation d'utilisation 13, alors que la chambre 36 est raccordée au circuit de retour.When the drawer 3 is in its neutral rest position, the bore 30 faces a solid part 34 of the stator which closes it, between two annular chambers 35 and 36. The chamber 35 communicates with the first use pipe 13, while the chamber 36 is connected to the return circuit.

De même, le perçage 32 est obturé au repos, par une partie pleine 37, située entre deux chambres annulaires 38 et 39. La chambre 38 communique avec la seconde canalisation d'utilisation 14, alors que la chambre 39 est reliée au circuit de retour.Similarly, the bore 32 is closed at rest, by a solid part 37, located between two annular chambers 38 and 39. The chamber 38 communicates with the second use pipe 14, while the chamber 39 is connected to the return circuit .

Entre les perçages 30 et 31, le stator définit, dans l'alésage, une partie pleine 40, devant laquelle est susceptible de se déplacer une gorge 41 du tiroir 3.Between the holes 30 and 31, the stator defines, in the bore, a solid part 40, in front of which is capable of moving a groove 41 of the drawer 3.

Autour du tiroir 3, dans la zone située autour du perçage 31 lorsque le tiroir 3 est poussé à droite (figure 1), se trouve une chambre statorique annulaire 42.Around the drawer 3, in the zone situated around the bore 31 when the drawer 3 is pushed to the right (FIG. 1), there is an annular stator chamber 42.

De même, à son extrémité opposée, le tiroir 3 possède une gorge 43 mobile devant une partie pleine 44 du stator. Autour du passage 33 lorsque le tiroir 3 est repoussé vers la gauche, se trouve une chambre statorique annulaire 45.Similarly, at its opposite end, the drawer 3 has a groove 43 movable in front of a solid part 44 of the stator. Around passage 33 when drawer 3 is pushed to the left, there is an annular stator chamber 45.

Les deux chambres 42 et 45 sont reliées par une canalisation 46 dite canalisation de load sensing.The two chambers 42 and 45 are connected by a pipe 46 called the load sensing pipe.

Des encoches de progressivité équipent les différentes gorges du tiroir, comme indiqué par exemple par les références 48, 49, 50, 51.Progressivity notches equip the different grooves of the drawer, as indicated for example by the references 48, 49, 50, 51.

Enfin, un premier clapet de gavage 52 est monté en parallèle sur la première canalisation d'utilisation 13. De même, un clapet de gavage 53 est monté en parallèle sur la seconde canalisation d'utilisation 14. Derrière les clapets 52 et 53, se trouve une chambre 54 reliée au circuit de retour d'huile.Finally, a first booster valve 52 is mounted in parallel on the first use pipe 13. Similarly, a booster valve 53 is mounted in parallel on the second user pipe 14. Behind the valves 52 and 53, is finds a chamber 54 connected to the oil return circuit.

Un clapet de surpression, respectivement 55 et 56, est prévu sur le côté de chacune des canalisations d'utilisation 13, 14, qui peuvent ainsi se déverser dans les chambres de retour, respectivement 36, 39.A pressure relief valve, respectively 55 and 56, is provided on the side of each of the use pipes 13, 14, which can thus flow into the return chambers, respectively 36, 39.

Le fonctionnement du tiroir commandé 3 va maintenant être décrit.The operation of the controlled drawer 3 will now be described.

En position neutre, les chambres 27, 35 et 38 sont obturés, de sorte que le vérin 12 est immobilisé alors qu'aucun débit ne passe dans le distributeur. En outre, la canalisation 46 communique par les gorges 41 et 43 respectivement avec la chambre 36 et la chambre 39, c'est-à-dire qu'elle est raccordée au circuit de retour.In the neutral position, the chambers 27, 35 and 38 are closed, so that the jack 12 is immobilized while no flow passes through the distributor. In addition, the pipe 46 communicates through the grooves 41 and 43 respectively with the chamber 36 and the chamber 39, that is to say that it is connected to the return circuit.

Lorsqu'une pression de pilotage est envoyée par l'ouverture 10, comme c'est le cas sur la figure 1, le tiroir 3 coulisse vers la droite avec une amplitude déterminée par la valeur de la pression de pilotage, qui s'équilibre avec la poussée antagoniste du ressort 4, plus ou moins comprimé. La pression d'alimentation de la chambre 27 est envoyée dans la canalisation 13 en passant par la gorge 49 et la chambre 35, alors que la canalisation 14 communique avec la chambre de retour 39 par la gorge 51. Chacune des gorges 49 et 51 détermine un étranglement dont la section est déterminée par la position du tiroir 3. En outre, la canalisation 46 communique à gauche avec la canalisation 13 par les passages 31, 28 et 30, tandis qu'à droite elle est obturée. La pression en aval de l'étranglement procuré par la gorge 49 est ainsi transmise à la canalisation 46.When a pilot pressure is sent through the opening 10, as is the case in FIG. 1, the slide 3 slides to the right with an amplitude determined by the value of the pilot pressure, which is balanced with the opposing thrust of the spring 4, more or less compressed. The supply pressure of the chamber 27 is sent into the line 13 through the groove 49 and the chamber 35, while the line 14 communicates with the return chamber 39 through the groove 51. Each of the grooves 49 and 51 determines a constriction whose cross section is determined by the position of the drawer 3. In addition, the pipe 46 communicates on the left with the pipe 13 through the passages 31, 28 and 30, while on the right it is closed. The pressure downstream of the throttle provided by the groove 49 is thus transmitted to the pipe 46.

Lorsqu'une pression de pilotage est envoyée par l'ouverture 11, le tiroir 3 coulisse vers la gauche jusqu'à une position déterminée par l'amplitude de la pression de pilotage. La pression d'alimentation de la chambre 27 est envoyée dans la canalisation 14 en passant par la gorge 50 et la chambre 38, alors que la canalisation 13 communique avec la chambre de retour 36 en passant par la gorge 48. Chacune des gorges 48 et 50 détermine un étranglement dont la section est déterminée par la position du tiroir 3. En outre, la canalisation 46 communique à droite avec la canalisation 14 par les perçages 33, 29 et 32, tandis qu'à gauche elle est obturée. La pression en aval de l'étranglement procurée par la gorge 50 est ainsi transmise à la canalisation 46.When a pilot pressure is sent through the opening 11, the slide 3 slides to the left to a position determined by the amplitude of the pilot pressure. The supply pressure of the chamber 27 is sent into the line 14 passing through the groove 50 and the chamber 38, while the line 13 communicates with the return chamber 36 through the groove 48. Each of the grooves 48 and 50 determines a constriction, the section of which is determined by the position of the drawer 3. In addition, the pipe 46 communicates on the right with the pipe 14 by the holes 33, 29 and 32, while on the left it is closed. The pressure downstream of the throttle provided by the groove 50 is thus transmitted to the pipe 46.

On voit ainsi qu'en position neutre, la canalisation 46 est mise à la pression du circuit de retour, tandis que dans chacune des positions de travail, elle est portée à la pression en aval de l'étranglement procuré par le tiroir 3 sur la ligne d'alimentation du vérin 12, c'est-à-dire à la pression d'utilisation de celui-ci.It can thus be seen that in the neutral position, the pipe 46 is put under the pressure of the return circuit, while in each of the working positions, it is brought to the pressure downstream of the throttle provided by the slide 3 on the cylinder 12 supply line, that is to say the operating pressure thereof.

Le sélecteur de circuit 99 (dit aussi fonction OU) a l'une de ses entrées qui communique avec la canalisation 46 par un canal 72, et son autre entrée qui communique avec un canal 73 relié à la canalisation de sortie du sélecteur de circuit d'un distributeur similaire. Ici, la pression dans la canalisation 46 est la plus forte, de sorte que le sélecteur de circuit 99 adopte la position illustrée où il transmet par sa sortie à la canalisation 74 la pression d'utilisation du vérin 12, qui est la pression d'utilisation la plus élevée de l'ensemble des récepteurs qu'alimente la génération de débit 71. Plus généralement, comme cela apparaît clairement sur la figure 2, c'est toujours la pression du récepteur le plus chargé qui est appliquée à la canalisation 74, cette pression dite de load sensing étant transmise à la génération de débit 71 qui produit une pression de service normalement égale à la pression de load sensing plus une constante.The circuit selector 99 (also called OR function) has one of its inputs which communicates with the pipe 46 by a channel 72, and its other input which communicates with a channel 73 connected to the output pipe of the circuit selector d '' a similar distributor. Here, the pressure in the line 46 is the highest, so that the circuit selector 99 adopts the illustrated position where it transmits by its output to the line 74 the operating pressure of the cylinder 12, which is the pressure of highest use of all receivers that feeds the flow generation 71. More generally, as is clearly seen in FIG. 2, it is always the pressure of the most loaded receiver which is applied to the pipe 74, this pressure known as load sensing being transmitted to the generation of flow 71 which produces a working pressure normally equal to the load sensing pressure plus a constant.

Le tiroir compensateur 16, dit aussi balance, est mobile dans un alésage 80 du stator 1 et comporte autour du canal 22 une gorge 81 qui produit, en fonction de la position du tiroir, un étranglement plus ou moins important en amont de l'étranglement procuré par le tiroir 3 sur la ligne d'alimentation du vérin 12, suivant la position prise par le tiroir 16.The compensating slide 16, also called a balance, is movable in a bore 80 of the stator 1 and has around the channel 22 a groove 81 which produces, depending on the position of the slide, a more or less significant constriction upstream of the constriction provided by the drawer 3 on the supply line of the jack 12, according to the position taken by the drawer 16.

Celui-ci comporte deux surfaces actives opposées, à gauche une surface 82 soumise à la pression en amont de l'étranglement procuré par le tiroir 3, et à droite une surface 83 soumise à la pression régnant dans la canalisation 46, c'est-à-dire la pression d'utilisation du vérin 12. Ce tiroir 16 est sollicité à gauche dans le sens de la fermeture de l'étranglement qu'il produit, et à droite dans le sens de l'ouverture.This comprises two opposite active surfaces, on the left a surface 82 subjected to the pressure upstream of the throttle provided by the slide 3, and on the right a surface 83 subjected to the pressure prevailing in the pipe 46, that is to say that is to say the operating pressure of the jack 12. This slide 16 is biased on the left in the direction of closing the throttle that it produces, and on the right in the direction of opening.

De chaque côté du tiroir 16, est disposé un piston mobile coaxialement, 84 à gauche et 85 à droite. Chaque piston 84 ou 85 vient en contact avec le tiroir compensateur par un téton, et coulisse dans un cylindre, respectivement 86 ou 87, vissé dans le stator 1 coaxialement à l'alésage 80, chaque cylindre étant ouvert du côté intérieur et fermé du côté extérieur, le cyclindre 86 traversant de façon étanche la canalisation 46.On each side of the drawer 16, is arranged a piston coaxially movable, 84 on the left and 85 on the right. Each piston 84 or 85 comes into contact with the compensating slide by a stud, and slides in a cylinder, respectively 86 or 87, screwed into the stator 1 coaxially with the bore 80, each cylinder being open on the inside and closed on the side. outside, the cylinder 86 sealingly crossing the pipe 46.

Les pistons 84 et 85 sont similaires et comportent chacun des passage en L qui permettent de faire communiquer la chambre située entre le piston et le fond du cylindre avec la canalisation 89 ou 90, respectivement. La canalisation 89 est reliée à la conduite de load sensing de la génération de débit, de sorte qu'elle est portée à la pression de load sensing, tandis que la canalisation 90 est reliée à la conduite de service de sorte qu'elle est portée à la pression de service. Les pistons 84 et 85 comportent chacun deux surfaces actives opposées, dont l'une (91 pour le vérin 84 et 92 pour le vérin 85) est en regard de la surface active correspondante du tiroir 16 (respectivement 82 et 83), et soumise à la même pression.The pistons 84 and 85 are similar and each have L-shaped passages which allow the chamber located between the piston and the bottom of the cylinder to communicate with the pipe 89 or 90, respectively. Line 89 is connected to the load sensing line of the flow generation, so that it is brought to the load sensing pressure, while the pipe 90 is connected to the service line so that it is brought to the service pressure. The pistons 84 and 85 each have two opposite active surfaces, one of which (91 for the cylinder 84 and 92 for the cylinder 85) is opposite the corresponding active surface of the drawer 16 (respectively 82 and 83), and subjected to the same pressure.

La deuxième surface active 93 du piston 84 est soumise à la pression de load sensing, et la deuxième surface active 94 du piston 85 est soumise à la pression de service. Un ressort 95, dont la force est réglable avec la vis 96, applique le piston 84 contre le tiroir 16.The second active surface 93 of the piston 84 is subjected to the load sensing pressure, and the second active surface 94 of the piston 85 is subjected to the operating pressure. A spring 95, the force of which is adjustable with the screw 96, applies the piston 84 against the drawer 16.

La valeur efficace des surfaces 82 et 83 est similaire (notée S₁ ), il en est de même pour la valeur efficace des surfaces 91 et 92 (notée S₂), et également de même pour la valeur efficace des surfaces 93 et 94 (notée S₃).The effective value of surfaces 82 and 83 is similar (denoted S₁), the same is true for the effective value of surfaces 91 and 92 (denoted S₂), and also the same for the effective value of surfaces 93 and 94 (denoted S₃ ).

En adoptant les mêmes notations que précédemment on a : P i -PU i = S₃(P-PU)/(S₁-S₂) - F/(S₁-S₂)

Figure imgb0003
   Les valeurs de S₁, S₂, S₃ et F sont choisies notamment en fonction des impératifs suivants :

  • les pistons 84 et 85 doivent rester en contact en service avec le tiroir 16 ;
  • le tiroir 16 doit se fermer pour une certaine valeur minimum a de P-PU, de sorte que : S₃.a = F ;
    Figure imgb0004
  • le tiroir 16 doit assurer en service normal, ou P-PU = c, une valeur b à Pi-PUi de sorte que : b(S₁-S₂) = S₃.c-F.
    Figure imgb0005
By adopting the same notations as above, we have: P i -COULD i = S₃ (P-PU) / (S₁-S₂) - F / (S₁-S₂)
Figure imgb0003
 The values of S₁, S₂, S₃ and F are chosen in particular according to the following imperatives:
  • the pistons 84 and 85 must remain in contact in service with the slide 16;
  • the drawer 16 must close for a certain minimum value a of P-PU, so that: S₃.a = F;
    Figure imgb0004
  • the drawer 16 must ensure in normal service, or P-PU = c, a value b to P i -PU i so that: b (S₁-S₂) = S₃.cF.
    Figure imgb0005

On notera que le premier impératif susvisé n'existe pas dans une variante où les pistons 84 et 85 sont solidairisés au tiroir 16.It will be noted that the first imperative mentioned above does not exist in a variant where the pistons 84 and 85 are secured to the drawer 16.

On voit aussi qu'on peut rattraper dans une certaine mesure les différences, dues aux tolérances de fabrication, qu'il pourrait y avoir dans les différents distributeurs sur les valeurs des surfaces actives.We also see that we can make up to some extent for the differences, due to manufacturing tolerances, that there could be in the different distributors on the values of active areas.

On observera que les transformations effectuées au distributeur décrit dans le brevet français FR-B-2 562 632 pour parvenir au présent distributeur, sont particulièrement simples à mettre en oeuvre.It will be observed that the transformations carried out at the distributor described in French patent FR-B-2,562,632 to reach the present distributor are particularly simple to implement.

On notera encore, que les conduits 89 et et 90 traversent tout le distributeur 70, de sorte qu'on conserve la possibilité d'effectuer tous les raccordements entre distributeurs, en accolant simplement ces derniers bout-à-bout.It will also be noted that the conduits 89 and and 90 pass through the entire distributor 70, so that the possibility remains of making all the connections between distributors, by simply joining these latter end-to-end.

Cette possibilité est illustrée de façon un peu plus complète sur la figure 2, qui montre schématiquement le distributeur 70 accolé à un distributeur similaire 70', tous les éléments se rapportant à celui-ci portant la même référence que précédemment mais affectée d'un indice prime.This possibility is illustrated in a slightly more complete manner in FIG. 2, which schematically shows the distributor 70 attached to a similar distributor 70 ', all the elements relating to the latter bearing the same reference as above but assigned an index premium.

On observera notamment la disposition en cascade des sélecteurs de circuit qui permet de ramener à la génération de débit 71 la pression du récepteur la plus élevée.In particular, the cascade arrangement of the circuit selectors will be observed, which allows the highest receiver pressure to be reduced to the generation of flow 71.

Dans un variante visant la simplification maximum, le distributeur le plus éloigné de la pompe, ici 70', ne reçoit pas de sélecteur de circuit avec une entrée reliée au réservoir, mais a son canal 74 directement connecté à la canalisation 46.In a variant aimed at maximum simplification, the distributor furthest from the pump, here 70 ′, does not receive a circuit selector with an input connected to the reservoir, but has its channel 74 directly connected to the pipe 46.

Claims (9)

  1. Proportional distributor for controlling a hydraulic receiver (12) by connecting it appropriately to a flow generator (71) producing a working pressure normally equal to a regulation pressure, so-called load sensing, applied to it plus a constant pressure; comprising: a controlled slide valve (3) whose position determines the cross-section of a flow restriction and a compensator slide valve (16) for regulating the pressure difference between the upstream and downstream sides of said flow restriction, the compensator slide valve automatically assuming a position in which it produces on the upstream side of said flow restriction a second flow restriction of appropriate cross-section, the compensator slide valve comprising two opposite active surfaces, a first surface (82) exposed to the pressure on the upstream side of the first flow restriction to urge the slide valve (16) in the closing direction and a second surface (83) exposed to the pressure on the downstream side of the first flow restriction to urge the compensator slide valve in the opening direction; and additional means whereby the compensator slide valve (16) is additionally urged in the closing direction by the load sensing pressure and in the opening direction by the working pressure; characterised in that said additional means are such that the compensator slide valve is also urged in the closing direction by a substantially constant force, said first and second active surfaces (82, 83) of the compensator slide valve and said additional means (84, 85, 95) being rated so that in service the pressure difference between the upstream and the downstream sides of the first flow restriction depends on the difference between the working pressure and the load sensing pressure according to a linear function with a strictly positive coefficient and a strictly negative constant.
  2. Distributor according to claim 1 characterised in that said additional means comprise:
    - on each side of the compensator slide valve (16), a piston (84, 85) movable coaxially and adapted to come into contact with or attached to the compensator slide valve, comprising two opposite active surfaces, a first surface (91, 92) which faces one of said active surfaces (82, 83) of the compensator slide valve and is exposed to the same pressure and a second surface (93, 94) exposed, for a first piston (84) whose first surface (91) faces the first surface (82) of the compensator slide valve, to the load sensing pressure and for a second piston (85) whose first surface (92) faces the second surface (83) of the compensator slide valve, to the working pressure; and
    - a spring (95) urging the first piston towards the compensator slide valve.
  3. Distributor according to claim 2 characterised in that said first and second active surfaces (82, 83) of the compensator slide valve are of similar size, said first active surfaces (91, 92) of the first and second pistons are of similar size and said second active surfaces (93, 94) of the first and second pistons are of similar size.
  4. Distributor according to claim 2 or claim 3 characterised in that it comprises a stator body (1) comprising a bore (80) in which the compensator slide valve (16) moves, said first and second pistons (84, 85) each moving in a cylinder (86, 87) attached coaxially to said body.
  5. Distributor according to claim 4 characterised in that it comprises transverse pipes (89, 90) respectively connected to the load sensing pipe and to the working pipe and each piston (84, 85) comprises a bore in order respectively to convey the load sensing pressure and the working pressure to a chamber situated between the piston (84, 85) and the back of the cylinder (86, 87).
  6. Distributor according to any one of claims 2 to 5 characterised in that the pistons (84, 85) and compensator slide valve (16) come into contact through lugs.
  7. Control system for a plurality of hydraulic receivers comprising for each of said receivers a distributor according to any one of claims 1 to 6.
  8. System according to claim 7 characterised in that each compensator slide valve operates according to the same linear function.
  9. System according to claim 7 characterised in that at least one of the distributors comprises a compensator slide valve operating according to a different linear function.
EP92400358A 1991-02-15 1992-02-11 Proportional valve and control system with a plurality of actuators having each such a valve Expired - Lifetime EP0500419B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9101848 1991-02-15
FR9101848A FR2672944A1 (en) 1991-02-15 1991-02-15 PROPORTIONAL DISTRIBUTOR AND CONTROL ARRANGEMENT OF A PLURALITY OF HYDRAULIC RECEIVERS COMPRISING FOR EACH RECEIVER SUCH A DISTRIBUTOR.

Publications (2)

Publication Number Publication Date
EP0500419A1 EP0500419A1 (en) 1992-08-26
EP0500419B1 true EP0500419B1 (en) 1995-11-22

Family

ID=9409779

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92400358A Expired - Lifetime EP0500419B1 (en) 1991-02-15 1992-02-11 Proportional valve and control system with a plurality of actuators having each such a valve

Country Status (5)

Country Link
US (1) US5222426A (en)
EP (1) EP0500419B1 (en)
JP (1) JPH04312202A (en)
DE (1) DE69206170T2 (en)
FR (1) FR2672944A1 (en)

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FR2694605B1 (en) * 1992-08-04 1994-11-10 Bennes Marrel Control assembly for a plurality of hydraulic receivers.
FR2694606B1 (en) * 1992-08-04 1994-11-04 Bennes Marrel Control assembly for a plurality of hydraulic receivers.
SE501289C2 (en) * 1993-06-24 1995-01-09 Voac Hydraulics Boraas Ab Controls for a hydraulic motor
US5715865A (en) * 1996-11-13 1998-02-10 Husco International, Inc. Pressure compensating hydraulic control valve system
US5878647A (en) * 1997-08-11 1999-03-09 Husco International Inc. Pilot solenoid control valve and hydraulic control system using same
US5890362A (en) * 1997-10-23 1999-04-06 Husco International, Inc. Hydraulic control valve system with non-shuttle pressure compensator
US5950429A (en) * 1997-12-17 1999-09-14 Husco International, Inc. Hydraulic control valve system with load sensing priority
JPH11201107A (en) * 1998-01-12 1999-07-27 Hitachi Constr Mach Co Ltd Pressure compensation valve
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Also Published As

Publication number Publication date
EP0500419A1 (en) 1992-08-26
JPH04312202A (en) 1992-11-04
FR2672944A1 (en) 1992-08-21
FR2672944B1 (en) 1995-01-27
DE69206170D1 (en) 1996-01-04
US5222426A (en) 1993-06-29
DE69206170T2 (en) 1996-08-22

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