EP0158757A1 - Method and apparatus for controlling with precision the pressure drop in a fluidum - Google Patents

Method and apparatus for controlling with precision the pressure drop in a fluidum Download PDF

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Publication number
EP0158757A1
EP0158757A1 EP84402570A EP84402570A EP0158757A1 EP 0158757 A1 EP0158757 A1 EP 0158757A1 EP 84402570 A EP84402570 A EP 84402570A EP 84402570 A EP84402570 A EP 84402570A EP 0158757 A1 EP0158757 A1 EP 0158757A1
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EP
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Prior art keywords
pressure
fluid
hydraulic
valve
progressive
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Granted
Application number
EP84402570A
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German (de)
French (fr)
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EP0158757B1 (en
Inventor
Dominique Marie-B. Casset
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Mors SA
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Mors SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B1/00—Vices
    • B25B1/06—Arrangements for positively actuating jaws
    • B25B1/18—Arrangements for positively actuating jaws motor driven, e.g. with fluid drive, with or without provision for manual actuation

Definitions

  • the present invention essentially relates to a method and a device for precisely adjusting the pressure drop of a fluid initially under high pressure, such as a hydraulic fluid, for example supplying a hydraulic unit, and the application of the method or of the device. in a group or a hydraulic power station, whether or not it is integrated, in particular with a machine table, or with any tool support device.
  • a fluid initially under high pressure such as a hydraulic fluid, for example supplying a hydraulic unit
  • French patent application No. 2 411_672 of the applicant relates to an autonomous hydraulic control assembly, in particular for a movable jaw of a vice for fixing a part in a precise position on a machine tool, this assembly comprising a pump two-stage hydraulic system, one stage for rapid advance and one stage for pressure build-up, an electric motor with two directions of rotation driving the pump, an adjustable pressure switch, a single-acting cylinder and a relief valve.
  • the pump discharged into the jack which clamps the vice; the start of clamping of the part causes a rise in pressure of the jack.
  • the low pressure stage is short-circuited while the high pressure stage perfect the tightening. Then the engine is stopped or restarted to maintain the cylinder at the desired clamping pressure, determined by the adjustable pressure switch.
  • the reverse rotation of the motor opens a second relief valve, connected to the jack, so that the vice is loosened.
  • the advantage of controlling the vice as it has just been mentioned lies in the ease of coupling to an apparatus for automatic control of machining cycles, tightening and loosening being obtained respectively in response to two signals. logical.
  • this prior assembly has the drawback of a sudden drop in the pressure of the hydraulic fluid when the second relief valve is opened by reversing the rotation of the engine. Indeed, during the machining cycles, it is often desirable, after having worked in a first step at a very high clamping pressure, to reduce this clamping pressure gradually without disadvantage for the continuation of the last machining steps. On the other hand, this pressure drop must be carried out with precision in order to keep the workpiece correctly tightened and to prevent it from moving which would greatly reduce the machining precision and would lead to scrap parts.
  • the present invention therefore aims to solve a new technical problem consisting in finding a solution making it possible to achieve a gradual pressure drop of a fluid initially under pressure while adjusting this pressure drop precisely.
  • the present invention provides for the first time a solution to this new technical problem.
  • the present invention relates according to one of its aspects to a method for precisely adjusting the pressure drop of a fluid initially under high pressure, such as a hydraulic fluid, for example supplying a hydraulic unit, comprising the detection of the pressure of said fluid, characterized in that a small leakage of fluid is produced for a determined time as a function of the pressure value to be reached, so as to cause a gradual drop in pressure to a determined pressure value .
  • the low fluid leakage is achieved by passing the fluid through an orifice of small calibrated section.
  • discrete pressure drops are produced by acting by successive actions of low fluid leakage.
  • a rapid drop in pressure is then produced by producing a greater leakage of fluid.
  • a two-stage valve is used to produce the pressure drops respectively progressive and rapid.
  • the operations are programmed and controlled automatically by a control center.
  • the present invention relates to also a device for precisely adjusting the pressure drop of a fluid under high pressure, such as a hydraulic fluid, for example supplying a hydraulic unit, comprising a member for detecting the pressure of the fluid, characterized in that it includes a pressure release device provided with a means capable of achieving a low fluid leakage.
  • this means of the pressure release device comprises an orifice of small calibrated section normally closed by a non-return valve called a progressive pressure release valve, pushed unilaterally against this orifice by an elastic return means, and in communication with fluid under pressure.
  • the orifice of small calibrated section is made in the body of an element comprising a cavity in which is mounted the progressive pressure release valve, said element itself forming a check valve called rapid pressure release valve pushed unilaterally against an orifice of appreciably larger section allowing a substantially greater leakage of fluid and a rapid drop in pressure.
  • this device further comprises a device for controlled actuation of the progressive pressure release valve.
  • this device for controlled actuation of the progressive pressure release valve comprises a clutch mechanism acting on a control member for opening the progressive pressure release valve, and preferably engaged by reversing of rotation of an energy motor.
  • the clutch mechanism comprises a wheel with inclined surface, either with limited angular displacement, or with toothed sector.
  • the device comprises a high pressure hydraulic pump with a mobile or fixed cylinder.
  • the present invention also relates to an application of the method or device described above in a group or a hydraulic power station, whether or not it is integrated, in particular into a machine table, or into any tool support device such as a pallet, square, cube, vice, etc.
  • FIGS. 1 and 2 show schematically the rear end of the jack, here having the general reference number 2, which can be seen more fully at FIG. 4 and bears a reference number 200, single acting comprising a piston 4, referenced 204 in FIG. 4.
  • This hydraulic group thus constituting a hydraulic control assembly, in particular for a movable jaw of a vice, comprises application of the device for adjusting the pressure drop with precision according to the invention, identified by the general reference number 6, of a fluid under high pressure, such as a hydraulic fluid 8.
  • This device for precisely adjusting the pressure drop according to the invention 6 comprises a detection member of the pressure of the fluid 8 in the cavity 10 defined at the rear of the piston 4 and which defines the clamping pressure of the piston 4.
  • the device according to the invention is characterized in that it comprises a device 12 for releasing the pressure, provided with means 14 capable of achieving a low fluid leakage.
  • this means 14 of the pressure release device 12 comprises an orifice 16 of small calibrated section normally closed by a check valve 18 called a progressive pressure release valve, having a needle end, pushed unilaterally against this orifice 16 by an elastic return means 20, unidirectional, such as a spring, and in communication with the fluid under pressure in the cavity 10, as can be seen from FIG. 1.
  • the orifice 16 of small calibrated section is produced in the body of an element 22 comprising a cavity 24 in which is mounted the valve 18 for progressive pressure release.
  • This element 22 itself forms a check valve 26 known as a rapid pressure release valve pushed back by elastic means 50 against an orifice 28 of section substantially larger than the section of the calibrated orifice 16, allowing a substantially greater leakage. of fluid and therefore a rapid drop in the pressure of the hydraulic fluid in the cavity 10.
  • valve 18 comprises a rod 29 slidingly mounted in a member 30 integral with the element 22 forming the valve 26 for rapid pressure release, the elastic return element 20 being mounted between the needle-forming end of the valve 18 and this organ 30.
  • the invention also includes a device 34 for controlled actuation of the progressive pressure release valve 18 which will now be described in more detail.
  • This device 34 for controlled actuation of the progressive pressure release valve 18 comprises a clutch mechanism 36 acting on a member 38 for controlling the opening of the progressive pressure release valve 18.
  • This mechanism 36 is preferably engaged by the reversal of rotation of an energy motor 39, the drive shaft 40 of which can be seen in FIG. 1.
  • This clutch mechanism 36 more specifically comprises a wheel 42 with an inclined surface 44 against which comes to bear a transmission element such as a ball 46 placed at the rear of the control member 38.
  • This control member 38 and l 'transmission element 46 are arranged in a displacement guide 48, such as a cylinder, in which is permanently disposed of the fluid as a hydraulic liquid.
  • the clutch mechanism 36 can be engaged so that the rotation of the wheel 42 then driven causes a displacement of the inclined surface 44 and the advance controlled in a precise manner, for example a few millimeters, of the transmission element 46 and therefore of the control member 38, thus exerting a pressure in the orifice 16 sufficient to cause a slight opening of the valve 18 for progressive pressure release by achieving low fluid leakage from cavity 10 under high pressure.
  • the rotation time of the energy motor 39 can be calculated precisely so that the wheel 42 is only rotated at a determined angle so as to cause only the opening of the valve 18 for falling progressive pressure.
  • This inclined surface can be provided so that when the wheel 42 continues to rotate, the movement of the control member 38 in the movement guide 48 causes pressure on the valve 18 so that a significant compression of the elastic return element 20 disposed on the rod 28 of the valve 18 and bearing against the member 30 integral with the element 22 forming a valve for rapid pressure drop, then causing a displacement to the left, in FIG. 1 , of the valve 22, by opening the orifice 28 of large section and then causing a rapid drop in pressure by the presence of a greater leakage of fluid.
  • an elastic return means 50 such as a spring is also provided at the rear of the element 22 to push it back into the closed position of the orifice 28.
  • FIG. 3 there is shown a particular clutch mechanism 36, which is here limited angular displacement.
  • a clutch mechanism is described in the applicant's prior French patent application No. 2,510,213 (see Figures 1 to 3 and the corresponding description). We will limit our here to recalling the structure of this clutch mechanism 36. It comprises between the shaft 40 of the energy motor 38 and the wheel 42 forming a crown, rollers 52, 54 cooperating with internal walls or housings of the wheel 42 respectively 42a, 42b which are clearly visible in FIG.
  • housings 42a, 42b are connected to a cylindrical arc 56 which defines with the shaft 40 a space in annular segment 58 of thickness less than the diameter of the rollers 52, 54 as described in the previous patent of the clutch mechanism.
  • the crown of the wheel 42 is completed between the housings 42a, 42b by a bridge 60 opposite the arc 56.
  • this bridge 60 are housed for pushers 62, 64, equipped with a spring for urging the rollers 52, 54 respectively towards the connecting ramps between the housings 42a, 42b and the cylindrical sector 56.
  • the springs are supported on an arcuate plate 66.
  • a stop finger 68 at the end of a sector fixed to the body of the device penetrates into the cylindrical segment 56 without touching either the shaft 40 or the crown 42, the latter being referenced 5a in the previous patent relating to the clutch system .
  • a low and high pressure hydraulic pump with two pistons as described in the applicant's prior patent 2,411,672 (filing No. 77 37 510), comprising a low pressure piston 24 with high flow rate and a high pressure piston 25 with low flow allowing the rise in high pressure.
  • the device according to the present invention comprises a hydraulic pump whose first low pressure stage comprises a gear pump 76 controlled by a pinion 75 connected to the shaft 40 of the motor with energy 39.
  • This gear pump 76 allows a higher flow rate with a minimum of space than the low pressure piston pump 24 described in the prior invention of the applicant 2,411,672.
  • the second stage here comprises a hydraulic pump 70 with piston which can be of the type described in detail in the prior French patent application of the Applicant No. 2,510,202.
  • essential difference between the piston pump in this earlier application by the applicant 2,510,202 and that shown in FIG. 2 lies in the fact that the cylinder 72, in which the piston 74 of the hydraulic eccentric pump 77 moves, is fixed and not oscillating like the oscillating cylinder 2 of this request from the applicant.
  • the eccentric 77 is rotated by having a common shaft 78 with a gear 79 engaged by the gear pump 76.
  • the piston pump 70 is supplied with hydraulic fluid by a supply circuit 80 comprising a non-return valve connected by a line symbolized 80a to the circuit 81 of the output of the gear pump 76 which is at low pressure and which supplies a large flow through the conduit 83 with non-return valve the cavity 10 at the rear of the piston 4 of the jack 2.
  • the output circuit of the piston pump 70 is referenced 82 and therefore constitutes a high pressure hydraulic fluid circuit. It should be noted that the coupling of the gear pump 76 to the piston pump 70 thus makes it possible to supply the piston pump with a hydraulic fluid in pre-pressure, which constitutes a radical technical advantage for increasing the overall efficiency of the pump. hydraulic (including gear pump and piston pump).
  • the hydraulic fluid is supplied from an external rigid reservoir 84 comprising an internal flexible envelope 85 containing the hydraulic fluid, the external reservoir 84 comprising an opening 88 for bringing the flexible envelope 86 to atmospheric pressure so that this envelope can contract when the hydraulic fluid is pumped into the cavity 90 hydraulic fluid reserve annex for the supply of the hydraulic pump comprising the gear pump 76 and the piston pump 70.
  • this cavity communicates with all the essential parts of the device, and in particular with the pressure release circuit formed by the valves 18 and 22 (not visible in Figure 2).
  • the large feed rate of the cavity 10 is ensured by the pump gear 76, the supply produced by the piston pump 70 being negligible at this stage.
  • FIGS. 4 to 7 another embodiment of a device according to the invention has been shown for which the device for progressive and rapid pressure release according to the invention is marked with the same references preceded by the number 2.
  • the reference 10 for example becomes 210 in FIG. 4.
  • the device according to the invention is integrated in an autonomous hydraulic control assembly for movable jaws 300 of a vice 302, of the type described in the applicant's prior French patent application 2 411 672. It will be observed with reference to FIG.
  • the clutch device 206 is formed by a toothed sector 330 which is engaged only in one direction of rotation of the motor, which is the direction of the arrow f mentioned in FIG. 6.
  • the hydraulic pump comprises a gear pump 276 driven by a gear 275 meshing with the shaft 240 of the energy motor 239 and which constitutes the low pressure hydraulic circuit as in the previous embodiment.
  • This gear pump 276 is coupled as in the previous embodiment with a piston pump 270 which is here with an oscillating cylinder like that described in the prior French patent application No. 2,510,202 of the applicant.
  • the supply of the piston pump 270 by the gear pump 276 is carried out by the conduit 280 which can be seen clearly in FIG. 5 which therefore achieves a pre-pressure of the hydraulic fluid supplied to the piston pump 270 called high pressure.
  • the overflow device 350 with valve 351 is shown in phantom line, making it possible to short-circuit most of the hydraulic fluid leaving the gear pump 276 during the pressure build-up. It is thus understood that when the pressure is too low, the valve 351 plays its role fully and prevents the return of the hydraulic fluid through the common cavity 290. When the hydraulic fluid rises in pressure, the valve 351 is opened so that the pump to gear no longer feeds the cavity 210 at the rear of the piston 202 and that the hydraulic fluid is immediately returned to the cavity forming a common reservoir 290.
  • the invention makes it possible to solve the technical problem described above in a particularly simple manner, by using, ultimately, a simple two-stage valve and that the efficiency of the hydraulic pump is improved by the combination of '' a gear pump for the low pressure circuit and a piston pump for the high pressure circuit.
  • the invention also includes all the means constituting technical equivalents of the means described as well as their various combinations.
  • the device according to the invention can be integrated into a miniature hydraulic power station with or without an integrated actuator, with or without an integrated reservoir, operating only for the time of the pressure rise or the time for the pressure to zero. , with the possibility of raising or lowering the pressure in stages with precision.
  • the unit can be either a compact assembly (cylinder + pump and clutch assembly + tank) for clamping parts, for example on a vice with machine tools, or integrated in a workpiece carrier or machine table assembly for actuating cylinder. clamping as described in the applicant's previous European patent application filed under No. 84 402 284.8.

Abstract

1. Method for controlling with precision the pressure drop of a hydraulic fluid, initially under high pressure, feeding a hydraulic set and comprising the detection of the pressure of the fluid, characterized in that it consists in effecting discrete pressure drops by acting with a certain number of successive actions of low fluid leakage, this number being determined as a function of the time necessary for reducing the initial fluid pressure to a desired pressure value to be obtained and in stopping the successive actions when the desired pressure value is detected.

Description

La présente invention concerne essentiellement un procédé et un dispositif de réglage avec précision de la chute de pression d'un fluide initialement sous pression élevée, tel qu'un fluide hydraulique par exemple alimentant un groupe hydraulique, et l'application du procédé ou du dispositif dans un groupe ou une centrale hydraulique, en étant intégré ou non, notamment à une table de machine, ou à tout dispositif de support d'outillage.The present invention essentially relates to a method and a device for precisely adjusting the pressure drop of a fluid initially under high pressure, such as a hydraulic fluid, for example supplying a hydraulic unit, and the application of the method or of the device. in a group or a hydraulic power station, whether or not it is integrated, in particular with a machine table, or with any tool support device.

La demande de brevet français N° 2 411_672 de la demanderesse a trait à un ensemble autonome de commande hydraulique, notamment pour mors mobile d'un étau pour la fixation d'une pièce en position précise sur une machine outil, cet ensemble comprenant une pompe hydraulique à deux étages, un étage pour l'avance rapide et un étage pour la montée en pression, un moteur électrique à double sens de rotation entraînant la pompe, un pressostat réglable, un vérin à simple effet et un clapet de décharge. Dans un sens de rotation, la pompe refoule dans le vérin qui serre l'étau; le début de serrage de la pièce entraîne une montée en pression du vérin. Lorsque la pression atteint une certaine valeur, l'étage basse pression est courtcircuité tandis que l'étage haute pression parfait le serrage. Ensuite le moteur est arrêté ou relancé pour maintenir le vérin à la pression de serrage désirée, déterminée par le pressostat réglable.French patent application No. 2 411_672 of the applicant relates to an autonomous hydraulic control assembly, in particular for a movable jaw of a vice for fixing a part in a precise position on a machine tool, this assembly comprising a pump two-stage hydraulic system, one stage for rapid advance and one stage for pressure build-up, an electric motor with two directions of rotation driving the pump, an adjustable pressure switch, a single-acting cylinder and a relief valve. In a direction of rotation, the pump discharged into the jack which clamps the vice; the start of clamping of the part causes a rise in pressure of the jack. When the pressure reaches a certain value, the low pressure stage is short-circuited while the high pressure stage perfect the tightening. Then the engine is stopped or restarted to maintain the cylinder at the desired clamping pressure, determined by the adjustable pressure switch.

La mise en rotation inverse du moteur ouvre un second clapet de décharge, branché sur le vérin, afin que l'étau soit desserré. L'intérêt de la commande de l'étau telle qu'elle vient d'être rappelée, réside dans la facilité de couplage à un appareillage de commande automatique de cycles d'usinage, les serrage et desserrage étant obtenus respectivement en réponse à deux signaux logiques.The reverse rotation of the motor opens a second relief valve, connected to the jack, so that the vice is loosened. The advantage of controlling the vice as it has just been mentioned lies in the ease of coupling to an apparatus for automatic control of machining cycles, tightening and loosening being obtained respectively in response to two signals. logical.

Cependant, cet ensemble antérieur présente l'inconvénient d'une chute brutale de la pression du fluide hydraulique lors de l'ouverture du second clapet de décharge par inversion de rotation du moteur. En effet, lors des cycles d'usinage, il est souvent souhaitable, après avoir travaillé dans une première étape à une pression de serrage très élevée, de réduire cette pression de serrage progressivement sans inconvénient pour la poursuite des dernières étapes d'usinage. D'autre part, cette chute de pression doit être réalisée avec précision afin de maintenir la pièce à usiner correctement serrée et éviter qu'elle ne bouge ce qui réduirait grandement la précision d'usinage et conduirait à des rebuts de pièces.However, this prior assembly has the drawback of a sudden drop in the pressure of the hydraulic fluid when the second relief valve is opened by reversing the rotation of the engine. Indeed, during the machining cycles, it is often desirable, after having worked in a first step at a very high clamping pressure, to reduce this clamping pressure gradually without disadvantage for the continuation of the last machining steps. On the other hand, this pressure drop must be carried out with precision in order to keep the workpiece correctly tightened and to prevent it from moving which would greatly reduce the machining precision and would lead to scrap parts.

La présente invention a donc pour but de résoudre un nouveau problème technique consistant à trouver une solution permettant de réaliser une chute de pression progressive d'un fluide initialement sous pression élevée tout en règlant cette chute de pression avec précision.The present invention therefore aims to solve a new technical problem consisting in finding a solution making it possible to achieve a gradual pressure drop of a fluid initially under pressure while adjusting this pressure drop precisely.

La présente invention fournit pour la première fois une solution à ce nouveau problème technique.The present invention provides for the first time a solution to this new technical problem.

La présente invention concerne selon l'un de ses aspects un procédé de réglage avec précision de la chute de pression d'un fluide initialement sous pression élevée, tel qu'un fluide hydraulique, par exemple alimentant un groupe hydraulique, comprenant la détection de la pression dudit fluide, caractérisé en ce qu'on réalise une faible fuite de fluide pendant un temps déterminé en fonction de la valeur de pression à at- teindre, de manière à provoquer une chute progressive de la pression jusqu'à une valeur de pression déterminée. De préférence, on réalise la faible fuite de fluide en faisant passer le fluide par un orifice de faible section calibré.The present invention relates according to one of its aspects to a method for precisely adjusting the pressure drop of a fluid initially under high pressure, such as a hydraulic fluid, for example supplying a hydraulic unit, comprising the detection of the pressure of said fluid, characterized in that a small leakage of fluid is produced for a determined time as a function of the pressure value to be reached, so as to cause a gradual drop in pressure to a determined pressure value . Preferably, the low fluid leakage is achieved by passing the fluid through an orifice of small calibrated section.

Selon un mode de réalisation préféré de ce procédé, on réalise des chutes discrètes de pression en agissant par actions successives de faible fuite de fluide.According to a preferred embodiment of this method, discrete pressure drops are produced by acting by successive actions of low fluid leakage.

Selon une autre caractéristique préférée du procédé selon l'invention, on réalise ensuite une chute rapide de pression en réalisant une plus grande fuite de fluide. Selon un mode de réalisation préféré pour réaliser ce procédé, on utilise un clapet bi-étagé pour réaliser les chutes de pression respectivement progressive et rapide.According to another preferred characteristic of the method according to the invention, a rapid drop in pressure is then produced by producing a greater leakage of fluid. According to a preferred embodiment for carrying out this method, a two-stage valve is used to produce the pressure drops respectively progressive and rapid.

Selon un mode de réalisation également préféré de ce procédé, les opérations sont programmées et commandées automatiquement par une centrale de commande.According to an equally preferred embodiment of this method, the operations are programmed and controlled automatically by a control center.

Selon un autre aspect, la présente invention concerne également un dispositif de réglage avec précision de la chute de pression d'un fluide sous pression élevée, tel qu'un fluide hydraulique, par exemple alimentant un groupe hydraulique, comprenant un organe de détection de la pression du fluide, caractérisé en ce qu'il comprend un dispositif de libération de la pression pourvu d'un moyen susceptible de réaliser une faible fuite de fluide. De préférence, ce moyen du dispositif de libération de la pression comprend un orifice de faible section calibré normalement obturé par un clapet de retenue dit clapet de libération progressive de pression, repoussé unilatéralement contre cet orifice par un moyen de rappel élastique, et en communication avec le fluide sous pression.According to another aspect, the present invention relates to also a device for precisely adjusting the pressure drop of a fluid under high pressure, such as a hydraulic fluid, for example supplying a hydraulic unit, comprising a member for detecting the pressure of the fluid, characterized in that it includes a pressure release device provided with a means capable of achieving a low fluid leakage. Preferably, this means of the pressure release device comprises an orifice of small calibrated section normally closed by a non-return valve called a progressive pressure release valve, pushed unilaterally against this orifice by an elastic return means, and in communication with fluid under pressure.

Selon une caractéristique particulière de ce dispositif, l'orifice de faible section calibré est réalisé dans le corps d'un élément comportant une cavité dans laquelle est monté le clapet de libération progressive de pression, ledit élément formant lui-même un clapet de retenue dit clapet de libération rapide de pression repoussé unilatéralement contre un orifice de section sensiblement plus grande permettant une fuite sensiblement plus grande de fluide et une chute rapide de pression.According to a particular characteristic of this device, the orifice of small calibrated section is made in the body of an element comprising a cavity in which is mounted the progressive pressure release valve, said element itself forming a check valve called rapid pressure release valve pushed unilaterally against an orifice of appreciably larger section allowing a substantially greater leakage of fluid and a rapid drop in pressure.

Selon un autre mode de réalisation préféré, ce dispositif comprend en outre un dispositif d'actionnement contrôlé du clapet de libération progressive de pression. Selon un mode de réalisation préféré, ce dispositif d'actionnement contrôlé du clapet de libération progressive de pression comprend un mécanisme à embrayage agissant sur un organe de commande d'ouverture du clapet de libération progressive de pression, et de préférence embrayé par l'inversion de rotation d'un moteur à énergie. Selon un mode de réalisation particulier, le mécanisme à embrayage comprend une roue à surface inclinée, soit à déplacement angulaire limité, soit à secteur denté. Selon une autre caractéristique de l'invention, le dispositif comprend une pompe hydraulique haute pression à cylindre mobile ou fixe. Et enfin, la présente invention concerne également une application du procédé ou dispositif précédemment décrit dans un groupe ou une centrale hydraulique, en étant intégré ou non, notamment à une table de machine, ou à tout dispositif de support d'outillage tel que palette, équerre, cube, étau, etc.According to another preferred embodiment, this device further comprises a device for controlled actuation of the progressive pressure release valve. According to a preferred embodiment, this device for controlled actuation of the progressive pressure release valve comprises a clutch mechanism acting on a control member for opening the progressive pressure release valve, and preferably engaged by reversing of rotation of an energy motor. According to a particular embodiment, the clutch mechanism comprises a wheel with inclined surface, either with limited angular displacement, or with toothed sector. According to another characteristic of the invention, the device comprises a high pressure hydraulic pump with a mobile or fixed cylinder. And finally, the present invention also relates to an application of the method or device described above in a group or a hydraulic power station, whether or not it is integrated, in particular into a machine table, or into any tool support device such as a pallet, square, cube, vice, etc.

D'autres buts, caractéristiques, et avantages de l'invention apparaîtront clairement à la lumière de la description explicative qui va suivre faite en référence aux dessins annexés représentant plusieurs modes de réalisation de l'invention donnés simplement à titre d'illustration et qui ne sauraient donc aucunement en limiter la porter. Dans les dessins :

  • La figure 1 représente une vue en coupe partielle, d'un groupe ou d'une centrale hydraulique, d'une table de machine, ou de tout dispositif de support d'outillage comportant l'application du procédé ou du dispositif de réglage avec précision de la chute de pression d'un fluide initialement sous pression élevée, selon la présente invention.
  • La figure 2 est une vue en coupe selon la ligne de trace II-II de la figure 1 représentant en outre le réservoir de fluide hydraulique.
  • La figure 3 représente une vue selon la flèche III de la figure 2 avec arrachement partiel montrant le mécanisme à embrayage à déplacement angulaire limité du dispositif d'actionnement contrôlé du clapet de libération progressive de pression.
  • La figure 4 représente un autre mode de réalisation d'un groupe ou d'une centrale hydraulique formant application du procédé ou du dispositif de réglage avec précision de la chute de pression d'un fluide initialement sous pression élevée, intégré à un chariot de commande d'un mors mobile d'un étau pour la fixation d'une pièce en position précise sur une machine outil, en coupe axiale selon la ligne de trace IV-IV de la figure 5.
  • La figure 5 représente une vue en coupe selon la ligne de trace V-V de la figure 4.
  • La figure 6 représente une vue en coupe selon la ligne de trace VI-VI de la figure 4, et
  • La figure 7 représente une vue en bout d'une pompe à pression hydraulique selon la flèche VII de la . figure 5.
Other objects, characteristics and advantages of the invention will become clear in the light of the explanatory description which follows, given with reference to the appended drawings representing several embodiments of the invention given simply by way of illustration and which do not would therefore in no way limit its wearing. In the drawings:
  • FIG. 1 represents a view in partial section, of a hydraulic unit or unit, of a machine table, or of any tool support device comprising the application of the method or of the precision adjustment device the pressure drop of a fluid initially under high pressure, according to the present invention.
  • Figure 2 is a sectional view along the trace line II-II of Figure 1 further showing the hydraulic fluid reservoir.
  • 3 shows a view along arrow III of Figure 2 with partial cutaway showing the clutch mechanism with limited angular displacement of the controlled actuation device of the progressive pressure release valve.
  • FIG. 4 represents another embodiment of a group or of a hydraulic unit forming an application of the method or of the device for precisely adjusting the pressure drop of a fluid initially under high pressure, integrated into a control carriage a movable jaw of a vice for fixing a part in a precise position on a machine tool, in axial section along the trace line IV-IV of FIG. 5.
  • FIG. 5 represents a sectional view along the trace line VV of FIG. 4.
  • FIG. 6 represents a sectional view along the trace line VI-VI of FIG. 4, and
  • FIG. 7 represents an end view of a hydraulic pressure pump according to arrow VII of the. figure 5.

En référence aux figures 1 et 2, un groupe ou une centrale hydraulique ayant le numéro de référence 1 pour table de machine, ou tout dispositif de support d'outillage tel que palette, équerre, cube, ou étau est par exemple du type de celle décrite dans la demande de brevet français antérieure de la demanderesse 2 411 672. On a représenté schématiquement aux figures 1 et 2 l'extrémité arrière du vérin, ici ayant le numéro de référence général 2, que l'on voit de manière plus complète à la figure 4 et porte un numéro de référence 200, à simple effet comportant un piston 4, référencé 204 à la figure 4.With reference to FIGS. 1 and 2, a group or a hydraulic unit having the reference number 1 for a machine table, or any tool support device such as a pallet, square, cube, or vice is for example of the type of that described in the applicant's prior French patent application 2,411,672. FIGS. 1 and 2 show schematically the rear end of the jack, here having the general reference number 2, which can be seen more fully at FIG. 4 and bears a reference number 200, single acting comprising a piston 4, referenced 204 in FIG. 4.

Ce groupe hydraulique constituant ainsi un ensemble de commande hydraulique notamment pour mors mobile d'un étau, comporte application du dispositif de réglage avec précision de la chute de pression selon l'invention, repéré par le numéro de référence général 6, d'un fluide sous pression élevée, tel qu'un fluide hydraulique 8. Ce dispositif de réglage avec précision de la chute de pression selon l'invention 6 comprend un organe de détection de la pression du fluide 8 dans la cavité 10 définie à l'arrière du piston 4 et qui définit la pression de serrage du piston 4.This hydraulic group thus constituting a hydraulic control assembly, in particular for a movable jaw of a vice, comprises application of the device for adjusting the pressure drop with precision according to the invention, identified by the general reference number 6, of a fluid under high pressure, such as a hydraulic fluid 8. This device for precisely adjusting the pressure drop according to the invention 6 comprises a detection member of the pressure of the fluid 8 in the cavity 10 defined at the rear of the piston 4 and which defines the clamping pressure of the piston 4.

Le dispositif selon l'invention est caractérisé en ce qu'il comprend un dispositif 12 de libération de la pression, pourvu d'un moyen 14 susceptible de réaliser une faible fuite de fluide. Selon un mode de réalisation préféré ce moyen 14 du dispositif 12 de libération de la pression comprend un orifice 16 de faible section calibré normalement obturé par un clapet 18 de retenue dit clapet de libération progressive de pression, ayant une extrémité formant pointeau, repoussé unilatéralement contre cet orifice 16 par un moyen de rappel élastique 20, unidirectionnel, tel qu'un ressort, et en communication avec le fluide sous pression dans la cavité 10, comme cela se conçoit bien à partir de la figure 1.The device according to the invention is characterized in that it comprises a device 12 for releasing the pressure, provided with means 14 capable of achieving a low fluid leakage. According to a preferred embodiment, this means 14 of the pressure release device 12 comprises an orifice 16 of small calibrated section normally closed by a check valve 18 called a progressive pressure release valve, having a needle end, pushed unilaterally against this orifice 16 by an elastic return means 20, unidirectional, such as a spring, and in communication with the fluid under pressure in the cavity 10, as can be seen from FIG. 1.

Selon un mode de réalisation préféré de l'invention, l'orifice 16 de faible section calibré est réalisé dans le corps d'un élément 22 comportant une cavité 24 dans laquelle est monté le clapet 18 de libération progressive de pression. Cet élément 22 forme lui-même un clapet 26 de retenue dit clapet de libération rapide de pression repoussé par un moyen élastique 50 contre un orifice 28 de section sensiblement plus grande que la section de l'orifice calibré 16, permettant une fuite sensiblement plus grande de fluide et donc une chute rapide de la pression du fluide hydraulique dans la cavité 10.According to a preferred embodiment of the invention, the orifice 16 of small calibrated section is produced in the body of an element 22 comprising a cavity 24 in which is mounted the valve 18 for progressive pressure release. This element 22 itself forms a check valve 26 known as a rapid pressure release valve pushed back by elastic means 50 against an orifice 28 of section substantially larger than the section of the calibrated orifice 16, allowing a substantially greater leakage. of fluid and therefore a rapid drop in the pressure of the hydraulic fluid in the cavity 10.

On observera que le clapet 18 comporte une tige 29 montée coulissante dans un organe 30 solidaire de l'élément 22 formant le clapet 26 de libération rapide de pression, l'élément de rappel élastique 20 étant monté entre l'extrémité formant pointeau du clapet 18 et cet organe 30.It will be observed that the valve 18 comprises a rod 29 slidingly mounted in a member 30 integral with the element 22 forming the valve 26 for rapid pressure release, the elastic return element 20 being mounted between the needle-forming end of the valve 18 and this organ 30.

L'invention comprend également un dispositif 34 d'actionnement contrôlé du clapet de libération progressive de pression 18 qui va être maintenant décrit plus en détail. Ce dispositif 34 d'actionnement contrôlé du clapet 18 de libération progressive de pression comprend un mécanisme 36 à embrayage agissant sur un organe 38 de commande d'ouverture du clapet 18 de libération progressive de pression. Ce mécanisme 36 est de préférence embrayé par l'inversion de rotation d'un moteur à énergie 39 dont on voit à la figure 1 l'arbre d'entraînement 40.The invention also includes a device 34 for controlled actuation of the progressive pressure release valve 18 which will now be described in more detail. This device 34 for controlled actuation of the progressive pressure release valve 18 comprises a clutch mechanism 36 acting on a member 38 for controlling the opening of the progressive pressure release valve 18. This mechanism 36 is preferably engaged by the reversal of rotation of an energy motor 39, the drive shaft 40 of which can be seen in FIG. 1.

Ce mécanisme 36 à embrayage comprend plus précisément une roue 42 à surface 44 inclinée contre laquelle vient prendre appui un élément de transmission tel qu'une bille 46 placée à l'arrière de l'organe de commande 38. Cet organe de commande 38 et l'élément de transmission 46 sont disposés dans un guide de déplacement 48, tel qu'un cylindre, dans lequel est en permanence disposé du fluide comme un liquide hydraulique. On comprend ainsi que par simple inversion de la rotation du moteur, le mécanisme à embrayage 36 puisse être embrayé de telle sorte que la rotation de la roue 42 alors entraînée provoque un déplacement de la surface inclinée 44 et l'avancée contrôlée de manière précise, par exemple de quelques millimètres, de l'élément de transmission 46 et donc de l'organe de commande 38, en exerçant ainsi une pression dans l'orifice 16 suffisante pour provoquer une légère ouverture du clapet 18 de libération progressive de pression en réalisant une faible fuite de fluide depuis la cavité 10 sous pression élevée. Il suffit d'inverser à nouveau le sens de rotation du moteur pour débrayer le mécanisme à embrayage qui revient alors à sa position de départ avec recul de l'élément de transmission 46, de l'organe de commande 48 et fermeture concomitante du clapet 18. Ainsi, l'ouverture de ce petit clapet est réalisée pendant un temps déterminé réglable à volonté, ce temps étant fonction de la valeur de pression à attein- dre. On comprend donc que l'on peut obtenir une chute progressive de pression jusqu'à une valeur de pression déterminée avec une très grande précision, d'autant plus que l'orifice 16 est de faible section et calibré en étant réalisé dans un élément particulier, ici l'élément 22 constituant lui-même un clapet de chute rapide de pression.This clutch mechanism 36 more specifically comprises a wheel 42 with an inclined surface 44 against which comes to bear a transmission element such as a ball 46 placed at the rear of the control member 38. This control member 38 and l 'transmission element 46 are arranged in a displacement guide 48, such as a cylinder, in which is permanently disposed of the fluid as a hydraulic liquid. It is thus understood that by simple reversal of the rotation of the motor, the clutch mechanism 36 can be engaged so that the rotation of the wheel 42 then driven causes a displacement of the inclined surface 44 and the advance controlled in a precise manner, for example a few millimeters, of the transmission element 46 and therefore of the control member 38, thus exerting a pressure in the orifice 16 sufficient to cause a slight opening of the valve 18 for progressive pressure release by achieving low fluid leakage from cavity 10 under high pressure. It is enough to reverse the direction of rotation of the motor again to disengage the clutch mechanism which then returns to its starting position with retraction of the transmission element 46, of the control member 48 and concomitant closure of the valve 18 Thus, the opening of this small valve is carried out for a determined time adjustable at will, this time being a function of the pressure value to be reached. It is therefore understood that it is possible to obtain a gradual drop in pressure up to a determined pressure value with very high precision, all the more since the orifice 16 is of small section and calibrated by being produced in a particular element. , here the element 22 itself constituting a rapid pressure drop valve.

On comprend également que l'on peut réaliser des chutes discrètes de pression en agissant par actions successives de faible fuite de fluide, ceci étant réalisé par de simples commandes d'inversion de la rotation du moteur à énergie 39. On comprend également qu'il est aisé de programmer toutes les opérations et de les commander automatiquement par une centrale de commande comme un micro-processeur, micro-ordinateur, etc.It is also understood that it is possible to produce discrete pressure drops by acting by successive actions of low fluid leakage, this being achieved by simple commands for reversing the rotation of the energy motor 39. It is also understood that is easy to program all the operations and to control them automatically by a control center such as a microprocessor, microcomputer, etc.

On comprend également que l'on peut calculer précisément le temps de rotation du moteur à énergie 39 de telle sorte que la roue 42 ne soit mise en rotation que selon un angle déterminé de manière à ne provoquer que l'ouverture du clapet 18 de chute progressive de pression. On peut prévoir cette surface inclinée de telle sorte que lors de la poursuite de la rotation de la roue 42 le déplacement de l'organe de commande 38 dans le guide de déplacement 48 provoque une pression telle sur le clapet 18 qu'il se produira une compression importante de l'élément de rappel élastique 20 disposé sur la tige 28 du clapet 18 et prenant appui contre l'organe 30 solidaire de l'élément 22 formant clapet de chute rapide de pression, provoquant alors un déplacement vers la gauche, à la figure 1, du clapet 22, en ouvrant l'orifice 28 de grande section et en provoquant alors une chute rapide de pression par la présence d'une plus grande fuite de fluide. Il a été indiqué qu'un moyen de rappel élastique 50 tel qu'un ressort est également prévu à l'arrière de l'élément 22 pour le repousser en position de fermeture de l'orifice 28.It is also understood that the rotation time of the energy motor 39 can be calculated precisely so that the wheel 42 is only rotated at a determined angle so as to cause only the opening of the valve 18 for falling progressive pressure. This inclined surface can be provided so that when the wheel 42 continues to rotate, the movement of the control member 38 in the movement guide 48 causes pressure on the valve 18 so that a significant compression of the elastic return element 20 disposed on the rod 28 of the valve 18 and bearing against the member 30 integral with the element 22 forming a valve for rapid pressure drop, then causing a displacement to the left, in FIG. 1 , of the valve 22, by opening the orifice 28 of large section and then causing a rapid drop in pressure by the presence of a greater leakage of fluid. It has been indicated that an elastic return means 50 such as a spring is also provided at the rear of the element 22 to push it back into the closed position of the orifice 28.

A la figure 3, on a représenté un mécanisme à embrayage 36 particulier, qui est ici à déplacement angulaire limité. Un tel mécanisme à embrayage est décrit dans la demande de brevet français antérieure de la demanderesse N° 2 510 213 (voir les figures 1 à 3 et la description correspondante). On se bornera ici à rappeler la structure de ce mécanisme à embrayage 36. Celui-ci comprend entre l'arbre 40 du moteur à énergie 38 et la roue 42 formant une couronne, des galets 52,54 coopérant avec des parois ou logements internes de la roue 42 respectivement 42a, 42b qui sont clairement visibles à la figure 1 du brevet français antérieur 2 510 213 où ils sont référencés 41 et 42 respectivement Ces logements 42a, 42b se raccordent à un arc cylindrique 56 qui définit avec l'arbre 40 un espace en segment annulaire 58 d'épaisseur inférieure au diamètre des galets 52, 54 comme cela est décrit dans le brevet précédent du mécanisme à embrayage. La couronne de la roue 42 se complète entre les logements 42a, 42b par un pont 60 à l'opposé de l'arc 56. Dans ce pont 60 sont ménagés des logements pour des poussoirs 62, 64, équipés de ressort pour solliciter les galets 52, 54 respectivement vers les rampes de jonction entre les logements 42a, 42b et le secteur 56 cylindrique. Les ressorts prennent appui sur une plaque arquée 66. Un doigt de butée 68 à l'extrémité d'un secteur fixé au corps du dispositif pénètre dans le segment cylindrique 56 sans toucher ni l'arbre 40 ni la couronne 42, celui-ci étant référencé 5a dans le brevet précédent relatif au système à embrayage.In Figure 3, there is shown a particular clutch mechanism 36, which is here limited angular displacement. Such a clutch mechanism is described in the applicant's prior French patent application No. 2,510,213 (see Figures 1 to 3 and the corresponding description). We will limit ourselves here to recalling the structure of this clutch mechanism 36. It comprises between the shaft 40 of the energy motor 38 and the wheel 42 forming a crown, rollers 52, 54 cooperating with internal walls or housings of the wheel 42 respectively 42a, 42b which are clearly visible in FIG. 1 of the prior French patent 2,510,213 where they are referenced 41 and 42 respectively These housings 42a, 42b are connected to a cylindrical arc 56 which defines with the shaft 40 a space in annular segment 58 of thickness less than the diameter of the rollers 52, 54 as described in the previous patent of the clutch mechanism. The crown of the wheel 42 is completed between the housings 42a, 42b by a bridge 60 opposite the arc 56. In this bridge 60 are housed for pushers 62, 64, equipped with a spring for urging the rollers 52, 54 respectively towards the connecting ramps between the housings 42a, 42b and the cylindrical sector 56. The springs are supported on an arcuate plate 66. A stop finger 68 at the end of a sector fixed to the body of the device penetrates into the cylindrical segment 56 without touching either the shaft 40 or the crown 42, the latter being referenced 5a in the previous patent relating to the clutch system .

Selon la présente invention, on peut utiliser une pompe hydraulique basse et haute pression à deux pistons telle que décrite dans le brevet antérieur de la demanderesse 2 411 672 (dépôt N° 77 37 510), comprenant un piston basse pression 24 à grand débit et un piston haute pression 25 à petit débit permettant la montée en haute pression.According to the present invention, it is possible to use a low and high pressure hydraulic pump with two pistons as described in the applicant's prior patent 2,411,672 (filing No. 77 37 510), comprising a low pressure piston 24 with high flow rate and a high pressure piston 25 with low flow allowing the rise in high pressure.

Cependant, de préférence et en référence à la coupe de la figure 2, le dispositif selon la présente invention comprend une pompe hydraulique dont le premier étage basse pression comprend une pompe à engrenage 76 commandée par un pignon 75 relié à l'arbre 40 du moteur à énergie 39. Cette pompe à engrenage 76 permet un débit plus important avec un minimum d'encombrement que la pompe à piston 24 basse pression décrite dans l'invention antérieure de la demanderesse 2 411 672.However, preferably and with reference to the section of FIG. 2, the device according to the present invention comprises a hydraulic pump whose first low pressure stage comprises a gear pump 76 controlled by a pinion 75 connected to the shaft 40 of the motor with energy 39. This gear pump 76 allows a higher flow rate with a minimum of space than the low pressure piston pump 24 described in the prior invention of the applicant 2,411,672.

Une autre caractéristique essentielle de la pompe hydraulique selon la présente invention est que le deuxième étage comprend ici une pompe hydraulique 70 à piston qui peut être du type décrit en détail dans la demande de brevet français antérieure de la demanderesse N° 2 510 202. Une différence essentielle entre la pompe à piston dans cette demande antérieure de la demanderesse 2 510 202 et celle représentée à la figure 2 réside dans le fait que le cylindre 72, dans lequel se déplace le piston 74 de la pompe hydraulique à excentrique 77, est fixe et non pas oscillant comme le cylindre oscillant 2 de cette demande de la demanderesse. L'excentrique 77 est commandé en rotation en ayant un arbre 78 commun avec un engrenage 79 engrené par la pompe à engrenage 76. En outre, la pompe à piston 70 est alimentée en fluide hydraulique par un circuit d'alimentation 80 comportant un clapet anti-retour relié par une conduite symbolisée 80a au circuit 81 de sortie de la pompe à engrenage 76 qui est en basse pression et qui alimente en grand débit par le conduit 83 avec clapet anti-retour la cavité 10 à l'arrière du piston 4 du vérin 2. Le circuit de sortie de la pompe à piston 70 est référencé 82 et constitue donc un circuit de fluide hydraulique haute pression. On doit noter que le couplage de la pompe à engrenage 76 à la pompe à piston 70 permet ainsi d'alimenter la pompe à piston avec un fluide hydraulique en pré-pression ce qui constitue un avantage technique radical pour augmenter le rendement global de la pompe hydraulique (comprenant la pompe à engrenage et la pompe à piston).Another essential characteristic of the hydraulic pump according to the present invention is that the second stage here comprises a hydraulic pump 70 with piston which can be of the type described in detail in the prior French patent application of the Applicant No. 2,510,202. essential difference between the piston pump in this earlier application by the applicant 2,510,202 and that shown in FIG. 2 lies in the fact that the cylinder 72, in which the piston 74 of the hydraulic eccentric pump 77 moves, is fixed and not oscillating like the oscillating cylinder 2 of this request from the applicant. The eccentric 77 is rotated by having a common shaft 78 with a gear 79 engaged by the gear pump 76. In addition, the piston pump 70 is supplied with hydraulic fluid by a supply circuit 80 comprising a non-return valve connected by a line symbolized 80a to the circuit 81 of the output of the gear pump 76 which is at low pressure and which supplies a large flow through the conduit 83 with non-return valve the cavity 10 at the rear of the piston 4 of the jack 2. The output circuit of the piston pump 70 is referenced 82 and therefore constitutes a high pressure hydraulic fluid circuit. It should be noted that the coupling of the gear pump 76 to the piston pump 70 thus makes it possible to supply the piston pump with a hydraulic fluid in pre-pressure, which constitutes a radical technical advantage for increasing the overall efficiency of the pump. hydraulic (including gear pump and piston pump).

Le fluide hydraulique est alimenté à partir d'un réservoir 84 rigide externe comportant une enveloppe 85 souple interne renfermant le fluide hydraulique, le réservoir externe 84 comportant une ouverture 88 de mise à la pression atmosphérique de l'enveloppe souple 86 de telle sorte que cette enveloppe puisse se contracter lorsque le fluide hydraulique est pompé dans la cavité 90 annexe de réserve de fluide hydraulique pour l'alimentation de la pompe hydraulique comprenant la pompe à engrenage 76 et la pompe à piston 70. On voit à la figure 2 que cette cavité communique avec toutes les parties essentielles du dispositif, et en particulier avec le circuit de libération de pression formé par les clapets 18 et 22 (non visibles à la figure 2). Pour le fonctionnement de cette pompe hydraulique pour la montée en pression en vue d'effectuer le serrage, le grand débit d'alimentation de la cavité 10 est assuré par la pompe à engrenage 76, l'alimentation réalisée par la pompe à piston 70 étant à ce stade négligeable. Lorsque la cavité 10 est pratiquement remplie de fluide hydrau- lique, on arrive à monter en pression dans la cavité, ce qui a pour effet de court-circuiter le circuit basse pression 81 de la pompe à engrenage 76, la majeure partie de ce débit étant retournée au réservoir général 90 tandis que la partie restante alimente par le circuit 80a, 80 la pompe à piston 70 qui remplit alors pleinement son rôle de montée en pression en vue d'effectuer le serrage.The hydraulic fluid is supplied from an external rigid reservoir 84 comprising an internal flexible envelope 85 containing the hydraulic fluid, the external reservoir 84 comprising an opening 88 for bringing the flexible envelope 86 to atmospheric pressure so that this envelope can contract when the hydraulic fluid is pumped into the cavity 90 hydraulic fluid reserve annex for the supply of the hydraulic pump comprising the gear pump 76 and the piston pump 70. We see in Figure 2 that this cavity communicates with all the essential parts of the device, and in particular with the pressure release circuit formed by the valves 18 and 22 (not visible in Figure 2). For the operation of this hydraulic pump for the pressure increase in order to carry out the tightening, the large feed rate of the cavity 10 is ensured by the pump gear 76, the supply produced by the piston pump 70 being negligible at this stage. When the cavity 10 is substantially filled with fluid the hydraulically ic, we come to increase the pressure in the cavity, thereby to short-circuit the low pressure circuit 81 to effect the gear pump 76, the majority of this flow being returned to the general reservoir 90 while the remaining part supplies by the circuit 80a, 80 the piston pump 70 which then fully fulfills its role of pressure build-up in order to perform the tightening.

En référence aux figures 4 à 7, on a représenté un autre mode de réalisation d'un dispositif selon l'invention pour lequel le dispositif de libération progressive et rapide de pression selon l'invention est repéré avec les mêmes repères précédés du chiffre 2. Ainsi, le repère 10 par exemple devient 210 à la figure 4. On observera simplement que selon ce mode de réalisation, le dispositif selon l'invention est intégré dans un ensemble autonome de commande hydraulique pour mors mobile 300 d'un étau 302, du type décrit dans la demande de brevet français antérieure de la demanderesse 2 411 672. On observera en référence à la figure 5 qu'il est prévu des réservoirs 304, 306 intégrés de fluide hydraulique dans lesquels est prévu respectivement un soufflet 308, 310 en communication avec la pression atmosphérique par la présence d'un orifice 312, 314 en vue de compenser le volume de fluide hydraulique prélevé pour réaliser la montée en pression dans la cavité 210 en vue d'actionner le mors mobile 300 par la poussée du piston 204. D'autre part, selon ce mode de réalisation, le dispositif à embrayage 206, représenté à la figure 6, est formé par un secteur denté 330 qui n'est engrené que dans un sens de rotation du moteur, qui est le sens de la flèche f mentionnée à la figure 6. Naturellement la même roue 202 à surface inclinée est présente de telle sorte que lors de l'engrènement du secteur denté 330, il se produit un actionnement du dispositif de libération progressive de pression de la même manière que celle décrite pour le mode de réalisation des figures 1 à 3, comme cela se conçoit bien dans la structure représentée également à la figure 4. Selon également ce mode de réalisation, la pompe hydraulique comprend une pompe à engrenage 276 entraînée par un engrenage 275 engrenant avec l'arbre 240 du moteur à énergie 239 et qui constitue le circuit hydraulique basse pression comme dans le mode de réalisation précédent. Cette pompe à engrenage 276 est couplée comme dans le mode de réalisation précédent avec une pompe à piston 270 qui est ici à cylindre oscillant comme celle décrite dans la demande de brevet français antérieure N° 2 510 202 de la demanderesse. Aussi, l'alimentation de la pompe à piston 270 par la pompe à engrenage 276 est réalisée par le conduit 280 que l'on voit bien à la figure 5 ce qui réalise donc une pré-pression du fluide hydraulique alimenté à la pompe à piston 270 dite haute pression.With reference to FIGS. 4 to 7, another embodiment of a device according to the invention has been shown for which the device for progressive and rapid pressure release according to the invention is marked with the same references preceded by the number 2. Thus, the reference 10 for example becomes 210 in FIG. 4. It will simply be observed that according to this embodiment, the device according to the invention is integrated in an autonomous hydraulic control assembly for movable jaws 300 of a vice 302, of the type described in the applicant's prior French patent application 2 411 672. It will be observed with reference to FIG. 5 that there are provided tanks 304, 306 integrated with hydraulic fluid in which a bellows 308, 310 respectively are provided in communication with atmospheric pressure by the presence of an orifice 312, 314 in order to compensate for the volume of hydraulic fluid withdrawn to achieve the pressure increase in the cavity 210 in order to actuate the jaw mob ile 300 by the pushing of the piston 204. On the other hand, according to this embodiment, the clutch device 206, represented in FIG. 6, is formed by a toothed sector 330 which is engaged only in one direction of rotation of the motor, which is the direction of the arrow f mentioned in FIG. 6. Naturally the same wheel 202 inclined surface is present so that during the engagement of the toothed sector 330, there is an actuation of the progressive pressure release device in the same manner as that described for the embodiment of Figures 1 to 3, as this can be easily seen in the structure also shown in FIG. 4. According to this embodiment also, the hydraulic pump comprises a gear pump 276 driven by a gear 275 meshing with the shaft 240 of the energy motor 239 and which constitutes the low pressure hydraulic circuit as in the previous embodiment. This gear pump 276 is coupled as in the previous embodiment with a piston pump 270 which is here with an oscillating cylinder like that described in the prior French patent application No. 2,510,202 of the applicant. Also, the supply of the piston pump 270 by the gear pump 276 is carried out by the conduit 280 which can be seen clearly in FIG. 5 which therefore achieves a pre-pressure of the hydraulic fluid supplied to the piston pump 270 called high pressure.

A la figure 7 on a représenté en trait fantôme le dispositif de trop plein 350 à clapet 351, permettant de court-circuiter la majeure partie du fluide hydraulique sortant de la pompe à engrenage 276 lors de la montée en pression. On comprend ainsi que lorsque la pression est trop faible, le clapet 351 joue pleinement son rôle et empêche le retour du fluide hydraulique par la cavité commune 290. Lorsque le fluide hydraulique monte en pression, le clapet 351 est ouvert de sorte que la pompe à engrenage n'alimente plus la cavité 210 à l'arrière du piston 202 et que le fluide hydraulique est immédiatement retourné à la cavité formant réservoir commun 290.In FIG. 7, the overflow device 350 with valve 351 is shown in phantom line, making it possible to short-circuit most of the hydraulic fluid leaving the gear pump 276 during the pressure build-up. It is thus understood that when the pressure is too low, the valve 351 plays its role fully and prevents the return of the hydraulic fluid through the common cavity 290. When the hydraulic fluid rises in pressure, the valve 351 is opened so that the pump to gear no longer feeds the cavity 210 at the rear of the piston 202 and that the hydraulic fluid is immediately returned to the cavity forming a common reservoir 290.

On voit également qu'on obtient les mêmes avantages que dans le mode de réalisation précédent.We also see that we get the same advantages than in the previous embodiment.

On comprend ainsi que l'invention permet de résoudre le problème technique précédemment décrit de manière particulièrement simple, par utilisation, en définitive, d'un simple clapet bi-étagé et que l'on améliore le rendement de la pompe hydraulique par la combinaison d'une pompe à engrenage pour le circuit basse pression et d'une pompe à piston pour le circuit haute pression.It is thus understood that the invention makes it possible to solve the technical problem described above in a particularly simple manner, by using, ultimately, a simple two-stage valve and that the efficiency of the hydraulic pump is improved by the combination of '' a gear pump for the low pressure circuit and a piston pump for the high pressure circuit.

Naturellement, l'invention comprend également tous les moyens constituant des équivalents techniques des moyens décrits ainsi que leurs diverses combinaisons. Ainsi, le dispositif selon l'invention peut être intégré à une centrale hydraulique miniature avec ou sans vérin intégré, avec ou sans réservoir intégré, ne fonctionnant que le temps de la montée de pression ou que le temps de la mise à zéro de la pression, avec la possibilité de monter ou descendre la pression par palier avec précision. Aussi, la centrale peut être soit un ensemble compact (vérin + ensemble pompe et embrayage + réservoir) pour brider des pièces par exemple sur un étau aux machines outils, ou intégré dans un ensemble porte-pièces ou tables de machine pour actionner des vérins de bridage comme décrit dans la demande de brevet européenne antérieure de la demanderesse déposée sous le n° 84 402 284.8.Naturally, the invention also includes all the means constituting technical equivalents of the means described as well as their various combinations. Thus, the device according to the invention can be integrated into a miniature hydraulic power station with or without an integrated actuator, with or without an integrated reservoir, operating only for the time of the pressure rise or the time for the pressure to zero. , with the possibility of raising or lowering the pressure in stages with precision. Also, the unit can be either a compact assembly (cylinder + pump and clutch assembly + tank) for clamping parts, for example on a vice with machine tools, or integrated in a workpiece carrier or machine table assembly for actuating cylinder. clamping as described in the applicant's previous European patent application filed under No. 84 402 284.8.

Claims (15)

1. Procédé de réglage avec précision de la chute de pression d'un fluide initialement sous pression élevée, tel qu'un fluide hydraulique, par exemple alimentant un groupe hydraulique comprenant la détection de la pression dudit fluide, caractérisé en ce que l'on réalise une faible fuite de fluide pendant un temps déterminé en fonction de la valeur de pression à at- teindre de manière à provoquer une chute progressive de la pression jusqu'à une valeur de pression déterminée.1. Method for precisely adjusting the pressure drop of a fluid initially under high pressure, such as a hydraulic fluid, for example supplying a hydraulic unit comprising the detection of the pressure of said fluid, characterized in that one achieves a low fluid leakage for a determined time as a function of the pressure value to be reached so as to cause a gradual drop in pressure to a determined pressure value. 2. Procédé selon la revendication 1, caractérisé en ce qu'on réalise cette faible fuite de fluide en faisant passer le fluide par un orifice de faible section calibré.2. Method according to claim 1, characterized in that this low fluid leakage is achieved by passing the fluid through an orifice of small calibrated section. 3. Procédé selon la revendication 1 ou 2, caractérisé en ce que l'on réalise des chutes discrètes de pression en agissant par actions successives de faible fuite de fluide.3. Method according to claim 1 or 2, characterized in that a discrete pressure drop is achieved by acting by successive actions of low fluid leakage. 4. Procédé selon l'une des revendications 1 à 3, caractérisé en ce que l'on réalise ensuite une chute rapide de pression en réalisant une plus grande fuite de fluide.4. Method according to one of claims 1 to 3, characterized in that a rapid pressure drop is then achieved by achieving a greater fluid leakage. 5. Procédé selon l'une des revendications 1 à 4, caractérisé en ce que l'on utilise un clapet bi-étagé pour réaliser les chutes de pression respectivement progressive et rapide.5. Method according to one of claims 1 to 4, characterized in that one uses a two-stage valve to achieve the pressure drops respectively progressive and rapid. 6. Procédé selon l'une quelconque des revendications 1 à 5, caractérisé en ce que les opérations sont programmées et commandées automatiquement par une centrale de commande.6. Method according to any one of claims 1 to 5, characterized in that the operations are programmed and controlled automatically by a control center. 7. Dispositif de réglage avec précision de la chute de pression d'un fluide sous pression élevée, tel qu'un fluide hydraulique, par exemple alimentant un groupe hydraulique, comprenant un organe de détection de la pression du fluide, caractérisé en ce qu'il comprend un dispositif (12) de libération de la pression pourvu d'un moyen (14) susceptible de réaliser une faible fuite de fluide.7. Device for precisely adjusting the pressure drop of a fluid under high pressure, such as a hydraulic fluid, for example supplying a hydraulic unit, comprising a fluid pressure detection member, characterized in that it comprises a device (12) for releasing the pressure provided with means (14) capable of producing a low leakage of fluid. 8. Dispositif selon la revendication 7, caractérisé en ce que le moyen (14) précité comprend un orifice (16) de faible section calibré normalement obturé par un clapet de retenue (18) dit clapet de libération progressive de pression, repoussé unilatéralement contre cet orifice (16) par un moyen de rappel élastique (20) et en communication avec le fluide sous pression.8. Device according to claim 7, characterized in that the above-mentioned means (14) comprises an orifice (16) of small calibrated section normally closed by a non-return valve (18) said progressive pressure release valve, pushed unilaterally against this orifice (16) by an elastic return means (20) and in communication with the pressurized fluid. 9. Dispositif selon la revendication 8, caractérisé en ce que l'orifice (16) de faible section calibré est réalisé dans le corps d'un élément (22) comportant une cavité (24) dans laquelle est monté le clapet (18) de libération progressive de pression, ledit élément (22) formant lui-même un clapet de retenue dit clapet de libération rapide de pression, repoussé unilatéralement contre un orifice (28) de section sensiblement plus grande permettant une fuite sensiblement plus grande de fluide.9. Device according to claim 8, characterized in that the orifice (16) of small calibrated section is produced in the body of an element (22) comprising a cavity (24) in which is mounted the valve (18) of progressive pressure release, said element (22) itself forming a check valve called rapid pressure release valve, pushed unilaterally against an orifice (28) of substantially larger section allowing a substantially greater leakage of fluid. 10. Dispositif selon l'une des revendications 7 à 9, caractérisé en ce qu'il comprend un dispositif (34) d'actionnement contrôlé du clapet de libération progressive de pression.10. Device according to one of claims 7 to 9, characterized in that it comprises a device (34) for controlled actuation of the progressive pressure release valve. 11.- Dispositif selon la revendication 10, caractérisé en ce que le dispositif d'actionnement contrôlé du clapet de libération progressive de pression comprend un mécanisme (36) à embrayage agissant sur un organe (38) de commande d'ouverture du clapet de libération progressive de pression, et de préférence embrayé par l'inversion de rotation d'un moteur à énergie (39).11.- Device according to claim 10, characterized in that the controlled actuation device of the progressive pressure release valve comprises a clutch mechanism (36) acting on a member (38) for controlling the opening of the progressive pressure release valve, and preferably engaged by the reversal of rotation of an energy motor (39). 12. Dispositif selon la revendication 11, caractérisé en ce que le mécanisme à embrayage (36) comprend une roue (42) à surface inclinée (44), soit à déplacement angulaire limité, soit à secteur denté.12. Device according to claim 11, characterized in that the clutch mechanism (36) comprises a wheel (42) with inclined surface (44), either with limited angular displacement, or with toothed sector. 13. Dispositif selon l'une des revendications 7 à 12, caractérisé en ce qu'il comprend une pompe hydraulique à piston haute pression à cylindre mobile ou fixe, de préférence fixe.13. Device according to one of claims 7 to 12, characterized in that it comprises a hydraulic high pressure piston pump with mobile or fixed cylinder, preferably fixed. 14. Dispositif selon la revendication 13, caractérisé en ce qu'il comprend une pompe hydraulique basse pression à engrenage couplée à la pompe hydraulique à piston de manière à délivrer à la pompe à piston un fluide hydraulique en pré-pression.14. Device according to claim 13, characterized in that it comprises a low pressure hydraulic pump with gear coupled to the hydraulic piston pump so as to deliver to the piston pump a hydraulic fluid in pre-pressure. 15. Application du procédé selon l'une quelconque des revendications 1 à 6, ou du dispositif selon l'une quelconque des revendications 7 à 14, dans un groupe ou une centrale hydraulique, étant intégré ou non, notamment à une table de machine, à tout dispositif de support d'outillage tel que palette, équerre, cube, étau.15. Application of the method according to any one of claims 1 to 6, or of the device according to any one of claims 7 to 14, in a group or a hydraulic power station, being integrated or not, in particular in a machine table, any tool support device such as pallet, square, cube, vice.
EP19840402570 1984-02-28 1984-12-12 Method and apparatus for controlling with precision the pressure drop in a fluidum Expired EP0158757B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8403062A FR2560298B1 (en) 1984-02-28 1984-02-28 METHOD AND DEVICE FOR ADJUSTING THE PRECISION OF THE PRESSURE DROP OF A FLUID INITIALLY AT HIGH PRESSURE, SUCH AS A HYDRAULIC FLUID FOR EXAMPLE SUPPLYING A HYDRAULIC GROUP, AND APPLICATION OF THE METHOD TO THE DEVICE IN A HYDRAULIC GROUP OR PLANT INTEGRATED OR NOT, ESPECIALLY IN A MACHINE TABLE OR ANY TOOL SUPPORT DEVICE
FR8403062 1984-02-28

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EP0158757A1 true EP0158757A1 (en) 1985-10-23
EP0158757B1 EP0158757B1 (en) 1989-03-15

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EP19840402570 Expired EP0158757B1 (en) 1984-02-28 1984-12-12 Method and apparatus for controlling with precision the pressure drop in a fluidum

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EP (1) EP0158757B1 (en)
DE (1) DE3477148D1 (en)
FR (1) FR2560298B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8503597A (en) * 1985-01-02 1986-08-01 Orion Yhtymae Oy METHOD FOR IDENTIFYING NUCLEIC ACIDS.
FR2651707A1 (en) * 1989-09-11 1991-03-15 Baudot Hardoll Limited-deformation vice

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2596853A (en) * 1950-06-08 1952-05-13 Helstrom Julmer Hydraulic vise having reservoir, pump, and cylinder carried by movable jaw

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2596853A (en) * 1950-06-08 1952-05-13 Helstrom Julmer Hydraulic vise having reservoir, pump, and cylinder carried by movable jaw

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8503597A (en) * 1985-01-02 1986-08-01 Orion Yhtymae Oy METHOD FOR IDENTIFYING NUCLEIC ACIDS.
FR2651707A1 (en) * 1989-09-11 1991-03-15 Baudot Hardoll Limited-deformation vice

Also Published As

Publication number Publication date
DE3477148D1 (en) 1989-04-20
FR2560298B1 (en) 1988-07-15
EP0158757B1 (en) 1989-03-15
FR2560298A1 (en) 1985-08-30

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