EP0585189A1 - High performance hydraulic actuator with control of play - Google Patents

High performance hydraulic actuator with control of play Download PDF

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Publication number
EP0585189A1
EP0585189A1 EP93440067A EP93440067A EP0585189A1 EP 0585189 A1 EP0585189 A1 EP 0585189A1 EP 93440067 A EP93440067 A EP 93440067A EP 93440067 A EP93440067 A EP 93440067A EP 0585189 A1 EP0585189 A1 EP 0585189A1
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EP
European Patent Office
Prior art keywords
cylinder
rod
cylinder according
head
expansion chamber
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EP93440067A
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German (de)
French (fr)
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EP0585189B1 (en
Inventor
Patrice Neumann
René Waeffler
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Usines Quiri & Cie Ste
Usines Quiri and Cie Ste
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Usines Quiri & Cie Ste
Usines Quiri and Cie Ste
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    • 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
    • F15B13/12—Special measures for increasing the sensitivity of the system

Definitions

  • the invention relates to a high performance hydraulic cylinder with clearance control.
  • the invention applies in particular to single or double-acting cylinders intended for a control function in displacement, speed or force.
  • This type of cylinder is intended more particularly to constitute damping devices for vehicles.
  • a high-performance cylinder In general, a high-performance cylinder must have the lowest possible level of friction. It is therefore essential to minimize friction between moving parts, especially at the joints.
  • oil film prevents direct metal-to-metal contact between moving parts during operation. It improves the sliding of the piston in the cylindrical envelope. This oil film must not be interrupted, but must remain stable and of constant thickness.
  • a difficulty results from the forces exerted on the rod, in particular the transverse forces, which create disturbances at the level of the oil film interposed between the facing surfaces of the rod and of the cylinder, which can cause irregular wear of the surfaces, or even their destruction in the case of violent or repeated constraints.
  • the increase in oil pressure causes the cylinder to expand, leading to greater clearance between the piston and the cylinder, and therefore to an increase in the oil leakage rate, which affects efficiency.
  • the object of the invention is to remedy the drawbacks of hydraulic cylinders linked to the problems of functional clearance, friction, and oil leakage, so as to produce an efficient cylinder capable of undergoing significant stresses, consuming little energy. and in which the leaks are low.
  • the jack according to the invention uses means for maintaining a minimum functional clearance between the piston and the cylinder in combination with means for balancing and regulating the oil film.
  • an expansion chamber is provided in the interior volume of the piston, this chamber being connected to the interior volume of the cylinder subjected to the hydrostatic actuation pressure of the jack.
  • Balancing chambers are regularly distributed around the periphery of the exterior surface of the cylinder, these chambers also being supplied with oil under pressure.
  • balancing chambers are associated with a set of anti-sticking grooves, so as to define a sliding interface and in particular an optimal longitudinal pressure gradient for efficient hydrodynamic guidance.
  • the general inventive idea consists in providing an internal expansion chamber to the piston associated with a set of anti-sticking grooves and specific external peripheral chambers regularly distributed around the periphery in order to reduce the functional clearance, to decrease and to control leaks. oil and improve the guidance.
  • a first embodiment consisting of a single-acting cylinder 1 comprising a cylinder body or hollow cylinder 2, having a cylindrical cavity 3 in which slides a rod 4 or piston cylinder general shape also cylindrical.
  • This pressure chamber of variable volume depending on the position of the sliding rod 4 of the jack is supplied with pressurized oil through a feed orifice 9 passing through the side wall 6 of the jack body 2 against the bottom of the cavity.
  • the rod or piston 4 is a cylindrical profiled rod as mentioned.
  • the facing sliding surfaces i.e. the outer surface 10 of the rod and the inner surface 11 of the side wall of the cylinder body, are machined with precision so as to leave only a minimal functional clearance.
  • the rod 4 has at its inner end a head 12.
  • the piston comprises, on the side of its end sliding in the cylinder, that is to say at the level of its head 12, a cavity forming an internal expansion chamber 13, delimited by a perimeter wall 14.
  • this expansion chamber When pressurized, this expansion chamber is intended to fill with pressurized oil and to compensate for the expansion of the wall 6 of the cylinder by an equivalent expansion of the perimeter wall 14 of the expansion chamber, so as to maintain the functional clearance between the rod head and the cylinder.
  • the expansion chamber may be produced, as shown, by a generally cylindrical cavity with an axis coincident with that of the rod, open in the bottom thereof, the stiffness of the perimeter wall 14 being equal to that of the wall 6 of the cylinder so as to generate an identical and joint expansion.
  • This expansion chamber 13 is therefore in permanent communication with the pressure chamber through an opening 15, for example a circular opening formed at the interior end of the head of the rod in the bottom wall 5 of the rod, on the entire diameter of the expansion chamber.
  • a set of suitable means is provided for maintaining a regular film of oil for guiding, balancing and controlling the leaks provided on the outer peripheral surface of the stem head.
  • Recesses in the form of annular peripheral grooves such as 16, preferably regularly spaced longitudinally, are provided on the surface of the rod.
  • anti-sticking grooves has the effect of eliminating, during operation, the local overpressures at a point on the periphery, which would cause the rod to be pressed against the diametrically opposite part of the wall. of the cylinder, distributing the pressurized oil over the entire periphery.
  • anti-sticking grooves are associated with balancing chambers 17, also provided on the external lateral sliding surface of the head of the rod.
  • the balancing chambers are formed by cavities 18, for example four cavities, of rectangular or other outline, in regular angular arrangement around the periphery of the surface. These cavities may be more or less numerous, but a minimum number of three will be necessary.
  • Each balancing chamber is supplied with pressurized oil, for example as shown, via a connection orifice 19 with the expansion chamber of the rod, through the wall of the latter.
  • a flow restrictor nozzle 20 is disposed in this orifice, so as to obtain a lower pressure in the balancing chambers.
  • the balancing chambers thus form, by the presence of oil under pressure, absorbent shock absorbing cushions providing a constant self-centering effect.
  • the centering and the control of the forces, in particular transverse, exerted on the piston rod are thus ensured permanently.
  • the oil pressure gradient in the oil film will depend on the relative longitudinal arrangement of the anti-sticking grooves and the balancing chambers as resulting from the calculations which are carried out according to conventional formulas.
  • the balancing chambers can be distributed in a ring on the sliding surface, the anti-sticking grooves being arranged symmetrically on either side of this ring.
  • the oil leaks corresponding to the functional clearance and to the oil film controlled and regulated by the device according to the invention are evacuated at the outlet end of the cylinder body by one or more lateral drainage orifices 21, and reintroduced in the circuit by a recycling loop with filtering (not shown).
  • a transverse peripheral scraper seal 22 held by a seal ring 23 eliminates any residual trace of oil on the moving surface of the rod.
  • the rod part located outside the body of the cylinder in partial or total extension of said cylinder is not soiled by threads or oil stains.
  • the scraper prevents outside dust, debris, dirt, etc. from entering between the sliding surfaces.
  • the jack according to the invention has the joint characteristics of great transverse stiffness, minimal clearance and optimal control of leaks. Its qualities and advantages allow it to target uses in particularly difficult conditions.
  • FIG. 4 represents a double-acting cylinder 24, also formed by a cylinder body 25 and a piston rod 26 sliding in a cavity 27 of said body thus forming a pressure chamber 28, provided, near the bottom, a supply port 29.
  • the piston also has an expansion chamber 30, the sliding surface 31 of which includes a suitable guide with anti-sticking grooves 32 and balancing chambers 33.
  • a second supply orifice 34 disposed near the outlet end of the cylinder body ensures the return of the piston rod.
  • the oil pressure is exerted for this purpose on a peripheral shoulder 35 formed on said rod.
  • the sliding of the rod is also ensured by a peripheral guide ring 36 containing a groove in which is housed a scraper seal 37.
  • all of the means for guiding and controlling movement and leaks can be provided in the sliding surface of the wall of the cylinder instead of the rod.
  • the invention can also be adapted to other types or forms of hydraulic cylinders.
  • the invention makes it possible to eliminate the seals between the rod and the cylinder of the jack, it also makes it possible to improve the operating characteristics of a conventional jack with seals, further comprising a dilation chamber and chambers balancing according to the invention.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Valve Device For Special Equipments (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)

Abstract

The high-performance hydraulic actuator comprises a cavity forming an expansion chamber (13) formed in the end of the rod (4) for joint expansion of the sliding walls (6, 14) of the cylinder (2) and of the said expansion chamber (13), and a set of non-stick grooves (16) and cavities (18) forming equilibrium chambers (17) formed in the sliding surface (10) of the rod (4), these means interacting for the purpose of maintaining a minimal operational clearance and of guiding the rod. <IMAGE>

Description

L'invention se rapporte à un vérin hydraulique hautes performances à contrôle du jeu.The invention relates to a high performance hydraulic cylinder with clearance control.

L'invention s'applique en particulier aux vérins à simple ou à double effet destinés à une fonction d'asservissement en déplacement, vitesse ou force.The invention applies in particular to single or double-acting cylinders intended for a control function in displacement, speed or force.

Ce type de vérin est destiné plus particulièrement à constituer des dispositifs amortisseurs pour véhicules.This type of cylinder is intended more particularly to constitute damping devices for vehicles.

De façon générale, un vérin performant doit présenter un niveau de frottement le plus faible possible. Il est donc essentiel de réduire au maximum les frottements entre les pièces en mouvement notamment au niveau des joints.In general, a high-performance cylinder must have the lowest possible level of friction. It is therefore essential to minimize friction between moving parts, especially at the joints.

Ces joints situés à la liaison entre la tige et le cylindre sont néanmoins soumis à des efforts répétés, tant longitudinaux que transversaux, ainsi qu'à un phénomène d'usure important. Leur détérioration s'avère particulièrement rapide dans le cas des vérins travaillant à de grandes vitesses de déplacement, ou dans un environnement soumis à des vibrations, mouvements de cisaillement, variations de température, agressions diverses, etc ...These joints located at the connection between the rod and the cylinder are nevertheless subjected to repeated forces, both longitudinal and transverse, as well as to a significant wear phenomenon. Their deterioration is particularly rapid in the case of cylinders working at high displacement speeds, or in an environment subjected to vibrations, shearing movements, temperature variations, various attacks, etc.

On réduit l'usure et la détérioration rapide des joints en créant un film d'huile entre les surfaces de coulissement.Wear and rapid deterioration of the seals are reduced by creating an oil film between the sliding surfaces.

La présence du film d'huile empêche, au cours du fonctionnement, le contact direct métal-métal entre les pièces en mouvement. Il améliore le coulissement du piston dans l'enveloppe cylindrique. Ce film d'huile ne doit pas être interrompu, mais demeurer stable et d'épaisseur constante.The presence of the oil film prevents direct metal-to-metal contact between moving parts during operation. It improves the sliding of the piston in the cylindrical envelope. This oil film must not be interrupted, but must remain stable and of constant thickness.

Une difficulté résulte des efforts exercés sur la tige, notamment les efforts transversaux, qui créent des perturbations au niveau du film d'huile interposé entre les surfaces en regard de la tige et du cylindre, pouvant provoquer une usure irrégulière des surfaces, voire leur destruction dans le cas de contraintes violentes ou répétées.A difficulty results from the forces exerted on the rod, in particular the transverse forces, which create disturbances at the level of the oil film interposed between the facing surfaces of the rod and of the cylinder, which can cause irregular wear of the surfaces, or even their destruction in the case of violent or repeated constraints.

Il est donc essentiel de connaître et de maîtriser le gradient de pression à tout instant et en tout point du film.It is therefore essential to know and control the pressure gradient at all times and at all points of the film.

Or les fuites sont inévitables en raison de la pression de fonctionnement nécessairement élevée. Afin de compenser ces pertes, on est contraint d'apporter un complément constant en huile qui permet de maintenir les caractéristiques du film d'huile, notamment sa continuité et sa régularité.Leaks are inevitable due to the necessarily high operating pressure. In order to compensate for these losses, it is necessary to provide a constant supplement of oil which makes it possible to maintain the characteristics of the oil film, in particular its continuity and regularity.

Ainsi, sur les vérins classiques, l'augmentation de la pression d'huile provoque une dilatation du cylindre conduisant à un jeu supérieur entre le piston et le cylindre, et donc à une augmentation du débit de fuite d'huile nuisant à l'efficacité du guidage et du contrôle des mouvements du piston dans le cylindre, ainsi qu'au maintien de la régularité du film d'huile entre les surfaces de coulissement en regard.Thus, on conventional cylinders, the increase in oil pressure causes the cylinder to expand, leading to greater clearance between the piston and the cylinder, and therefore to an increase in the oil leakage rate, which affects efficiency. guiding and controlling the movements of the piston in the cylinder, as well as maintaining the regularity of the oil film between the facing sliding surfaces.

A ces inconvénients, il faut ajouter le risque de décollement du joint qui peut être entraîné hors de son logement au cours du fonctionnement, en raison de l'augmentation du jeu entre la tige et le cylindre, avec pour résultat son extrusion et sa destruction.To these drawbacks, we must add the risk of detachment of the seal which can be driven out of its housing during operation, due to the increased clearance between the rod and the cylinder, resulting in its extrusion and destruction.

Le but de l'invention est de remédier aux inconvénients des vérins hydrauliques liés aux problèmes de jeu fonctionnel, de frottements, et de fuite d'huile, de manière à réaliser un vérin performant capable de subir des contraintes importantes, consommant peu d'énergie et dans lequel les fuites sont faibles.The object of the invention is to remedy the drawbacks of hydraulic cylinders linked to the problems of functional clearance, friction, and oil leakage, so as to produce an efficient cylinder capable of undergoing significant stresses, consuming little energy. and in which the leaks are low.

A cet effet, le vérin selon l'invention utilise des moyens de maintien d'un jeu fonctionnel minimal entre le piston et le cylindre en combinaison avec des moyens d'équilibrage et de régulation du film d'huile.To this end, the jack according to the invention uses means for maintaining a minimum functional clearance between the piston and the cylinder in combination with means for balancing and regulating the oil film.

Ainsi, une chambre de dilatation est ménagée dans le volume intérieur du piston, cette chambre étant reliée au volume intérieur du cylindre soumis à la pression hydrostatique d'actionnement du vérin.Thus, an expansion chamber is provided in the interior volume of the piston, this chamber being connected to the interior volume of the cylinder subjected to the hydrostatic actuation pressure of the jack.

Des chambres d'équilibrage sont régulièrement réparties sur le pourtour de la surface extérieure du cylindre, ces chambres étant également alimentées en huile sous pression.Balancing chambers are regularly distributed around the periphery of the exterior surface of the cylinder, these chambers also being supplied with oil under pressure.

Ces chambres d'équilibrage sont associées à un ensemble de gorges anti-collage, de façon à définir une interface de coulissement et notamment un gradient longitudinal optimal des pressions pour un guidage hydrodynamique performant.These balancing chambers are associated with a set of anti-sticking grooves, so as to define a sliding interface and in particular an optimal longitudinal pressure gradient for efficient hydrodynamic guidance.

Les avantages du vérin selon l'invention sont notamment les suivants :

  • . la réduction importante du débit de fuite d'huile due au contrôle du jeu et du gradient de pression hydrostatique au sein du film d'huile ;
  • . le maintien d'un film d'huile régulier et constant sur la totalité des surfaces en regard, dans toutes les conditions d'utilisation ;
  • . l'absence de contact mécanique et donc d'usure entre le piston et le cylindre en cours de fonctionnement ;
  • . en conséquence, l'augmentation considérable de la durée d'utilisation sans dégradation des performances initiales.
The advantages of the jack according to the invention are in particular the following:
  • . the significant reduction in the oil leakage rate due to the control of the clearance and of the hydrostatic pressure gradient within the oil film;
  • . maintaining a regular and constant oil film on all facing surfaces, under all conditions of use;
  • . the absence of mechanical contact and therefore of wear between the piston and the cylinder during operation;
  • . consequently, the considerable increase in the duration of use without degrading the initial performance.

On a ainsi la possibilité de fabriquer des vérins présentant un rapport poids/performance notablement amélioré, ainsi qu'une excellente capacité de résistance aux efforts transversaux, l'invention concernant tous types de vérins notamment les vérins à simple ou à double effet, et ceux utilisés à titre d'amortisseurs.There is thus the possibility of manufacturing cylinders having a significantly improved weight / performance ratio, as well as an excellent capacity for resistance to transverse forces, the invention relating to all types of cylinders in particular single or double acting cylinders, and those used as shock absorbers.

Les caractéristiques techniques et d'autres avantages de l'invention sont consignés dans la description qui suit, effectuée à titre d'exemple non limitatif sur un mode d'exécution en référence aux dessins accompagnants dans lesquels :

  • . la figure 1 est une vue en coupe longitudinale d'un vérin à simple effet selon l'invention ;
  • . la figure 2 est une vue en coupe longitudinale partielle d'un détail du vérin à simple effet selon l'invention au niveau des parois de coulissement en regard ;
  • . la figure 3 est une vue en coupe transversale du vérin selon la ligne III-III de la figure 1 ;
  • . la figure 4 est une vue en coupe longitudinale d'un vérin à double effet selon l'invention.
The technical characteristics and other advantages of the invention are set out in the description which follows, given by way of nonlimiting example on an embodiment with reference to accompanying drawings in which:
  • . Figure 1 is a longitudinal sectional view of a single-acting cylinder according to the invention;
  • . Figure 2 is a partial longitudinal sectional view of a detail of the single-acting cylinder according to the invention at the opposite sliding walls;
  • . Figure 3 is a cross-sectional view of the cylinder along line III-III of Figure 1;
  • . Figure 4 is a longitudinal sectional view of a double-acting cylinder according to the invention.

L'idée générale inventive consiste à prévoir une chambre de dilatation intérieure au piston associée à un ensemble de gorges anti-collage et de chambres périphériques extérieures spécifiques régulièrement réparties sur le pourtour en vue de réduire le jeu fonctionnel, de diminuer et de contrôler les fuites d'huile et d'améliorer le guidage.The general inventive idea consists in providing an internal expansion chamber to the piston associated with a set of anti-sticking grooves and specific external peripheral chambers regularly distributed around the periphery in order to reduce the functional clearance, to decrease and to control leaks. oil and improve the guidance.

On décrit ci-après en référence à la figure 1 un premier mode de réalisation consistant en un vérin à simple effet 1 comprenant un corps de vérin ou cylindre creux 2, présentant une cavité 3 cylindrique dans laquelle coulisse une tige 4 ou piston de vérin de forme générale également cylindrique.We describe below with reference to Figure 1 a first embodiment consisting of a single-acting cylinder 1 comprising a cylinder body or hollow cylinder 2, having a cylindrical cavity 3 in which slides a rod 4 or piston cylinder general shape also cylindrical.

L'espace délimité par une paroi de fond 5 que présente la tige 4 et par des parois latérale 6 et de fond 7 de la cavité 3 forme une chambre de pression 8. Cette chambre de pression, de volume variable en fonction de la position de la tige coulissante 4 du vérin, est alimentée en huile sous pression par un orifice d'alimentation 9 traversant la paroi latérale 6 du corps de vérin 2 contre le fond de la cavité.The space delimited by a bottom wall 5 presented by the rod 4 and by side walls 6 and bottom 7 of the cavity 3 forms a pressure chamber 8. This pressure chamber, of variable volume depending on the position of the sliding rod 4 of the jack is supplied with pressurized oil through a feed orifice 9 passing through the side wall 6 of the jack body 2 against the bottom of the cavity.

La tige ou piston 4 est une tige profilée cylindrique comme mentionné. Les surfaces de coulissement en regard, c'est-à-dire la surface extérieure 10 de la tige et la surface intérieure 11 de la paroi latérale du corps de vérin, sont usinées avec précision de façon à ne laisser subsister qu'un jeu fonctionnel minimal.The rod or piston 4 is a cylindrical profiled rod as mentioned. The facing sliding surfaces, i.e. the outer surface 10 of the rod and the inner surface 11 of the side wall of the cylinder body, are machined with precision so as to leave only a minimal functional clearance.

La tige 4 présente au niveau de son extrémité intérieure une tête 12.The rod 4 has at its inner end a head 12.

Le piston comporte, du côté de son extrémité coulissant dans le cylindre, c'est à dire au niveau de sa tête 12, une cavité formant une chambre de dilatation intérieure 13, délimitée par une paroi périmétrique 14.The piston comprises, on the side of its end sliding in the cylinder, that is to say at the level of its head 12, a cavity forming an internal expansion chamber 13, delimited by a perimeter wall 14.

Lors de la mise sous pression, cette chambre de dilatation est destinée à se remplir d'huile sous pression et à compenser la dilatation de la paroi 6 du cylindre par une dilatation équivalente de la paroi périmétrique 14 de la chambre de dilatation, de manière à maintenir le jeu fonctionnel entre la tête de la tige et le cylindre.When pressurized, this expansion chamber is intended to fill with pressurized oil and to compensate for the expansion of the wall 6 of the cylinder by an equivalent expansion of the perimeter wall 14 of the expansion chamber, so as to maintain the functional clearance between the rod head and the cylinder.

La chambre de dilatation pourra être réalisée, comme représenté, par une cavité de forme générale cylindrique d'axe confondu avec celui de la tige, ouverte dans le fond de celle-ci, la raideur de la paroi périmétrique 14 étant égale à celle de la paroi 6 du cylindre de façon à engendrer une dilatation identique et conjointe.The expansion chamber may be produced, as shown, by a generally cylindrical cavity with an axis coincident with that of the rod, open in the bottom thereof, the stiffness of the perimeter wall 14 being equal to that of the wall 6 of the cylinder so as to generate an identical and joint expansion.

Cette chambre de dilatation 13 est donc en communication permanente avec la chambre de pression par une ouverture 15, par exemple une ouverture circulaire ménagée au niveau de l'extrémité intérieure de la tête de la tige dans la paroi de fond 5 de la tige, sur la totalité du diamètre de la chambre de dilatation.This expansion chamber 13 is therefore in permanent communication with the pressure chamber through an opening 15, for example a circular opening formed at the interior end of the head of the rod in the bottom wall 5 of the rod, on the entire diameter of the expansion chamber.

Ainsi, les pressions exercées sur les parois de la chambre de pression 8 du cylindre et de la chambre de dilatation 13 de la tige étant égales, leurs dilatations correspondantes n'entraînent aucune augmentation du jeu fonctionnel.Thus, the pressures exerted on the walls of the pressure chamber 8 of the cylinder and of the expansion chamber 13 of the rod being equal, their corresponding expansions do not cause any increase in the functional clearance.

D'autre part, comme mentionné, un film d'huile permanent et constant est créé et maintenu dans l'espace fonctionnel entre les surfaces de coulissement en regard.On the other hand, as mentioned, a permanent and constant oil film is created and maintained in the functional space between the sliding surfaces opposite.

Coopérant avec le moyen de maintien d'un jeu minimal que constitue la chambre de dilatation, il est prévu un ensemble de moyens adaptés de maintien d'un film d'huile régulier pour le guidage, l'équilibrage et le contrôle des fuites ménagés sur la surface périphérique extérieure de la tête de la tige.Cooperating with the means for maintaining a minimum clearance constituted by the expansion chamber, a set of suitable means is provided for maintaining a regular film of oil for guiding, balancing and controlling the leaks provided on the outer peripheral surface of the stem head.

Des retraits en forme de gorges périphériques annulaires telles que 16, de préférence régulièrement espacées longitudinalement, sont ménagés sur la surface de la tige.Recesses in the form of annular peripheral grooves such as 16, preferably regularly spaced longitudinally, are provided on the surface of the rod.

La présence de ces gorges annulaires 16 dites gorges anti-collage a pour effet d'éliminer, en cours de fonctionnement, les surpressions locales en un point de la périphérie, ce qui amènerait la tige à se plaquer contre la partie diamétralement opposée de la paroi du cylindre, en répartissant l'huile sous pression sur l'ensemble de la périphérie.The presence of these annular grooves 16 called anti-sticking grooves has the effect of eliminating, during operation, the local overpressures at a point on the periphery, which would cause the rod to be pressed against the diametrically opposite part of the wall. of the cylinder, distributing the pressurized oil over the entire periphery.

Ces gorges anti-collage sont associées à des chambres d'équilibrage 17, également ménagées sur la surface latérale extérieure de coulissement de la tête de la tige.These anti-sticking grooves are associated with balancing chambers 17, also provided on the external lateral sliding surface of the head of the rod.

Les chambres d'équilibrage sont constituées par des cavités 18, par exemple quatre cavités, de contour rectangulaire ou autre, en disposition angulaire régulière sur le pourtour de la surface. Ces cavités pourront être plus ou moins nombreuses, mais un nombre minimal de trois sera nécessaire.The balancing chambers are formed by cavities 18, for example four cavities, of rectangular or other outline, in regular angular arrangement around the periphery of the surface. These cavities may be more or less numerous, but a minimum number of three will be necessary.

Chaque chambre d'équilibrage est alimentée en huile sous pression, par exemple comme représenté, par l'intermédiaire d'un orifice de liaison 19 avec la chambre de dilatation de la tige, à travers la paroi de cette dernière.Each balancing chamber is supplied with pressurized oil, for example as shown, via a connection orifice 19 with the expansion chamber of the rod, through the wall of the latter.

Un gicleur 20 limiteur de débit est disposé dans cet orifice, de façon à obtenir une pression inférieure dans les chambres d'équilibrage.A flow restrictor nozzle 20 is disposed in this orifice, so as to obtain a lower pressure in the balancing chambers.

Les chambres d'équilibrage forment ainsi, par la présence de l'huile sous pression, des coussins absorbants amortisseurs apportant un effet constant d'auto-centrage. Le centrage et le contrôle des efforts, notamment transversaux, exercés sur la tige de piston sont ainsi assurés en permanence.The balancing chambers thus form, by the presence of oil under pressure, absorbent shock absorbing cushions providing a constant self-centering effect. The centering and the control of the forces, in particular transverse, exerted on the piston rod are thus ensured permanently.

Le gradient de pression d'huile dans le film d'huile sera fonction de la disposition longitudinale relative des gorges anti-collage et des chambres d'équilibrage telle que résultant des calculs qui s'effectuent selon les formules classiques.The oil pressure gradient in the oil film will depend on the relative longitudinal arrangement of the anti-sticking grooves and the balancing chambers as resulting from the calculations which are carried out according to conventional formulas.

De manière préférée, les chambres d'équilibrage pourront être réparties en anneau sur la surface de coulissement, les gorges anti-collage étant disposées symétriquement de part et d'autre de cet anneau.Preferably, the balancing chambers can be distributed in a ring on the sliding surface, the anti-sticking grooves being arranged symmetrically on either side of this ring.

Les fuites d'huile correspondant au jeu fonctionnel et au film d'huile contrôlé et régulé par le dispositif selon l'invention, sont évacuées à l'extrémité de sortie du corps de vérin par un ou plusieurs orifices de drainage 21 latéraux, et réintroduites dans le circuit par une boucle de recyclage avec filtrage (non représenté).The oil leaks corresponding to the functional clearance and to the oil film controlled and regulated by the device according to the invention are evacuated at the outlet end of the cylinder body by one or more lateral drainage orifices 21, and reintroduced in the circuit by a recycling loop with filtering (not shown).

Un joint racleur 22 périphérique transversal maintenu par une bague porte-joint 23 élimine toute trace résiduelle d'huile sur la surface en mouvement de la tige. Ainsi, la partie de tige se trouvant à l'extérieur du corps du vérin en extension partielle ou totale dudit vérin n'est pas souillée par des filets ou taches d'huile.A transverse peripheral scraper seal 22 held by a seal ring 23 eliminates any residual trace of oil on the moving surface of the rod. Thus, the rod part located outside the body of the cylinder in partial or total extension of said cylinder is not soiled by threads or oil stains.

Inversement, le racleur empêche les poussières, débris, souillures, etc, extérieurs de pénétrer entre les surfaces de coulissement.Conversely, the scraper prevents outside dust, debris, dirt, etc. from entering between the sliding surfaces.

Le vérin selon l'invention présente les caractéristiques conjointes d'une grande raideur transversale, d'un jeu minimal et d'un contrôle optimal des fuites. Ses qualités et ses avantages lui permettent de viser des utilisations dans des conditions particulièrement difficiles.The jack according to the invention has the joint characteristics of great transverse stiffness, minimal clearance and optimal control of leaks. Its qualities and advantages allow it to target uses in particularly difficult conditions.

La figure 4 représente un vérin 24 à double effet, également formé d'un corps 25 de vérin et d'une tige 26 de piston coulissant dans une cavité 27 dudit corps formant ainsi une chambre de pression 28, munie, à proximité du fond, d'un orifice d'alimentation 29.FIG. 4 represents a double-acting cylinder 24, also formed by a cylinder body 25 and a piston rod 26 sliding in a cavity 27 of said body thus forming a pressure chamber 28, provided, near the bottom, a supply port 29.

Le piston présente également une chambre de dilatation 30, dont la surface de coulissement 31 comprend un guidage adapté avec gorges anti-collage 32 et des chambres d'équilibrage 33.The piston also has an expansion chamber 30, the sliding surface 31 of which includes a suitable guide with anti-sticking grooves 32 and balancing chambers 33.

Un second orifice d'alimentation 34 disposé à proximité de l'extrémité de sortie du corps de vérin assure le retour de la tige de piston. La pression de l'huile s'exerce à cet effet sur un épaulement périphérique 35 ménagé sur ladite tige.A second supply orifice 34 disposed near the outlet end of the cylinder body ensures the return of the piston rod. The oil pressure is exerted for this purpose on a peripheral shoulder 35 formed on said rod.

Le coulissement de la tige est en outre assuré par un anneau de guidage 36 périphérique contenant une gorge dans laquelle se loge un joint racleur 37.The sliding of the rod is also ensured by a peripheral guide ring 36 containing a groove in which is housed a scraper seal 37.

Les avantages et le fonctionnement de ce type de vérin selon l'invention sont similaires.The advantages and the operation of this type of jack according to the invention are similar.

On notera qu'à titre de variante, l'ensemble des moyens de guidage et de contrôle du mouvement et des fuites peut être prévu dans la surface de coulissement de la paroi du cylindre au lieu de la tige.It will be noted that, as a variant, all of the means for guiding and controlling movement and leaks can be provided in the sliding surface of the wall of the cylinder instead of the rod.

L'invention peut également être adaptée à d'autres types ou formes de vérins hydrauliques.The invention can also be adapted to other types or forms of hydraulic cylinders.

Notamment, si l'invention permet de supprimer les joints entre la tige et le cylindre du vérin, elle permet également d'améliorer les caractéristiques de fonctionnement d'un vérin classique à joints, comportant en outre une chambre de dilatation et des chambres d'équilibrage selon l'invention.In particular, if the invention makes it possible to eliminate the seals between the rod and the cylinder of the jack, it also makes it possible to improve the operating characteristics of a conventional jack with seals, further comprising a dilation chamber and chambers balancing according to the invention.

Il est en outre bien entendu qu'au-delà des moyens décrits, diverses modifications évidentes et variantes simples entrent dans le cadre de la présente invention.It is further understood that beyond the means described, various obvious modifications and simple variants fall within the scope of the present invention.

Claims (13)

Vérin hydrostatique à contrôle du jeu comprenant un cylindre (2) et une tige (4) de piston comportant à son extrémité intérieur une tête (12) coulissant dans le cylindre (2) délimitant une cavité (3) ménageant une chambre de pression (8), la tête (12) de la tige (4) comportant des moyens de création et de maintien d'un film d'huile, caractérisé en ce que : . une chambre de dilatation (13) est conformée dans la tête (12) de la tige (4), ladite chambre (13) communiquant avec la chambre de pression (8) par au moins une ouverture (15) d'alimentation ; . les moyens de création et de maintien d'un film d'huile régulier comprennent des cavités (18) formant des chambres d'équilibrage (17) alimentées en huile sous pression, ménagées dans la surface de coulissement (10) de la tête (12) de la tige (4). Hydrostatic cylinder with clearance control comprising a cylinder (2) and a piston rod (4) comprising at its inner end a head (12) sliding in the cylinder (2) delimiting a cavity (3) providing a pressure chamber (8 ), the head (12) of the rod (4) comprising means for creating and maintaining an oil film, characterized in that: . an expansion chamber (13) is formed in the head (12) of the rod (4), said chamber (13) communicating with the pressure chamber (8) by at least one supply opening (15); . the means for creating and maintaining a regular oil film comprise cavities (18) forming balancing chambers (17) supplied with oil under pressure, formed in the sliding surface (10) of the head (12 ) of the rod (4). Vérin selon la revendication 1, caractérisé en ce que l'ouverture (15) de la chambre de dilatation (13) est ménagée sur la totalité du fond de la tête de tige.Cylinder according to claim 1, characterized in that the opening (15) of the expansion chamber (13) is formed over the entire bottom of the rod head. Vérin selon les revendications 1 ou 2, caractérisé en ce que la chambre de dilatation (13) est de forme cylindrique.Cylinder according to claims 1 or 2, characterized in that the expansion chamber (13) is of cylindrical shape. Vérin selon l'une des revendications 1, 2 ou 3, caractérisé en ce que la chambre de dilatation (13) et le cylindre (2) ont des parois respectives (14,6) de raideurs sensiblement égales.Cylinder according to one of claims 1, 2 or 3, characterized in that the expansion chamber (13) and the cylinder (2) have respective walls (14,6) of substantially equal stiffness. Vérin selon l'une quelconque des revendications précédentes, caractérisé en ce que les chambres d'équilibrage (17) sont disposées en anneau sur la surface de coulissement (10) de la tige (4).Cylinder according to any one of the preceding claims, characterized in that the balancing chambers (17) are arranged in a ring on the sliding surface (10) of the rod (4). Vérin selon l'une quelconque des revendications précédentes, caractérisé en ce que les cavités (18) formant les chambres d'équilibrage (17) sont de contour rectangulaire.Cylinder according to any one of the preceding claims, characterized in that the cavities (18) forming the balancing chambers (17) are of rectangular contour. Vérin selon l'une quelconque des revendications précédentes, caractérisé en ce que les chambres d'équilibrage (17) sont alimentées à partir de la chambre de dilatation (13), chacune par l'intermédiaire d'un gicleur (20) limiteur de débit.Cylinder according to any one of the preceding claims, characterized in that the balancing chambers (17) are supplied from the expansion chamber (13), each via a nozzle (20) flow limiter . Vérin selon l'une quelconque des revendications précédentes, caractérisé en ce que des gorges (16) anti-collage sont ménagées dans la surface de coulissement (10) de la tête (12) de tige, de part et d'autre des chambres d'équilibrage (17).Cylinder according to any one of the preceding claims, characterized in that anti-sticking grooves (16) are provided in the sliding surface (10) of the rod head (12), on either side of the chambers d 'balancing (17). Vérin selon la revendication 8, caractérisé en ce que les gorges (16) anti-collage sont disposées symétriquement de part et d'autre de l'emplacement des chambres d'équilibrage (17).Cylinder according to claim 8, characterized in that the anti-sticking grooves (16) are arranged symmetrically on either side of the location of the balancing chambers (17). Vérin selon l'une quelconque des revendications précédentes, caractérisé en ce que les chambres d'équilibrage (17) sont ménagées, non dans la surface de coulissement (10) de la tête (12) de tige, mais dans la surface de coulissement (11) du cylindre (2).Cylinder according to any one of the preceding claims, characterized in that the balancing chambers (17) are provided, not in the sliding surface (10) of the rod head (12), but in the sliding surface ( 11) of the cylinder (2). Vérin selon l'une quelconque des revendications 8 à 10, caractérisé en ce que les gorges (16) anti-collage sont ménagées, non dans la surface (10) de la tête (12) de tige mais dans la surface de coulissement (11) du cylindre (2).Cylinder according to any one of Claims 8 to 10, characterized in that the anti-sticking grooves (16) are provided, not in the surface (10) of the rod head (12) but in the sliding surface (11 ) of the cylinder (2). Vérin selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit vérin est à simple effet.Cylinder according to any one of the preceding claims, characterized in that said cylinder is single acting. Vérin selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit vérin est à double effet.Cylinder according to any one of the preceding claims, characterized in that said cylinder is double-acting.
EP93440067A 1992-08-25 1993-08-25 High performance hydraulic actuator with control of play Expired - Lifetime EP0585189B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9210341 1992-08-25
FR9210341A FR2695170B1 (en) 1992-08-25 1992-08-25 High performance hydraulic cylinder with clearance control.

Publications (2)

Publication Number Publication Date
EP0585189A1 true EP0585189A1 (en) 1994-03-02
EP0585189B1 EP0585189B1 (en) 1996-05-29

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Application Number Title Priority Date Filing Date
EP93440067A Expired - Lifetime EP0585189B1 (en) 1992-08-25 1993-08-25 High performance hydraulic actuator with control of play

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EP (1) EP0585189B1 (en)
AT (1) ATE138725T1 (en)
DE (1) DE69302873T2 (en)
FR (1) FR2695170B1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2907304A (en) * 1957-04-04 1959-10-06 Macks Elmer Fred Fluid actuated mechanism
GB986585A (en) * 1962-04-19 1965-03-17 David Theodore Nelson Williams Improvements in or relating to hydraulic systems
DE1236877B (en) * 1960-04-29 1967-03-16 Goerlitzer Maschb Veb Control piston
GB1206068A (en) * 1968-05-31 1970-09-23 Kampf Maschf Erwin Fluid operated, low frictional actuator
JPS599305A (en) * 1982-07-05 1984-01-18 Toyooki Kogyo Co Ltd Hydraulic cylinder

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2907304A (en) * 1957-04-04 1959-10-06 Macks Elmer Fred Fluid actuated mechanism
DE1236877B (en) * 1960-04-29 1967-03-16 Goerlitzer Maschb Veb Control piston
GB986585A (en) * 1962-04-19 1965-03-17 David Theodore Nelson Williams Improvements in or relating to hydraulic systems
GB1206068A (en) * 1968-05-31 1970-09-23 Kampf Maschf Erwin Fluid operated, low frictional actuator
JPS599305A (en) * 1982-07-05 1984-01-18 Toyooki Kogyo Co Ltd Hydraulic cylinder

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 8, no. 94 (M - 293)<1581> 28 April 1984 (1984-04-28) *

Also Published As

Publication number Publication date
EP0585189B1 (en) 1996-05-29
ATE138725T1 (en) 1996-06-15
DE69302873D1 (en) 1996-07-04
FR2695170A1 (en) 1994-03-04
FR2695170B1 (en) 1994-10-14
DE69302873T2 (en) 1997-01-02

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