EP0505297B1 - Hydraulic actuator with piston positioning means - Google Patents

Hydraulic actuator with piston positioning means Download PDF

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Publication number
EP0505297B1
EP0505297B1 EP19920420084 EP92420084A EP0505297B1 EP 0505297 B1 EP0505297 B1 EP 0505297B1 EP 19920420084 EP19920420084 EP 19920420084 EP 92420084 A EP92420084 A EP 92420084A EP 0505297 B1 EP0505297 B1 EP 0505297B1
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EP
European Patent Office
Prior art keywords
drum
shaft
housing
encoder
actuator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP19920420084
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German (de)
French (fr)
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EP0505297A1 (en
Inventor
Jean-Paul Auvergne
Pierre Clavel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GEC Alsthom Societe DEtudes et de Montages SA
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GEC Alsthom Societe DEtudes et de Montages SA
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Publication of EP0505297A1 publication Critical patent/EP0505297A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/28—Means for indicating the position, e.g. end of stroke
    • F15B15/2815—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
    • F15B15/283—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT using a cable wrapped on a drum and attached to the piston

Definitions

  • the present invention relates to double-acting hydraulic cylinders which are fitted with a servo system capable of imposing on their movable rod a succession of displacements in accordance with a programmable setpoint of extensions and contractions.
  • FIG. 1 of the drawing appended hereto The general arrangement of this type of jack has been schematically recalled in FIG. 1 of the drawing appended hereto.
  • the reference 1 designates the end of the fixed cylinder inside which the piston slides axially, the rear face of the latter being made integral with a flexible link 2 through a double-articulated fastener.
  • the opposite end of this link 2 is wound in a helical groove made in the wall of a drive drum 3.
  • the latter is wedged on a transverse shaft 4 which, on either side of said drum, carries an absolute encoder 5 connected to an electronic management unit, and a spiral spring 6 for keeping the link 22 constant under tension, which spring is housed in a housing 7 fixed laterally to the casing 8 which supports the shaft 4.
  • the invention essentially consists in producing the drive drum in the form of a hollow cylindrical wall provided with a single transverse flange which is offset in the direction of one of the ends of said wall, so as to define in said drum a free space capable of forming housing for at least one of the two driven elements associated with it.
  • This drum 10 comprises a hollow cylindrical wall 10 a whose outer surface is hollowed out by a groove 10 b with a helical profile, while its inner surface is connected to a transverse flange 10 c pierced axially at 10 d . It is essential to observe that this flange 10 c is offset with respect to the median plane of the cylindrical wall 10 a , so as to be in fact disposed at one of the edges thereof.
  • this drum 10 is fixed, inside a casing 11, on a shaft 12 introduced through its axial opening 10 d .
  • the cylindrical wall 10 a cooperates with two bearings 13 held inside the aforementioned casing; a reinforcement bearing 14 has also been provided interposed between a shoulder of the cover 11b of the casing 11 and the end of a socket 15 keyed onto the shaft 12.
  • a longitudinal bore capable of receiving a pin 16 forming a mooring point for one of the ends of a spiral spring 17, the opposite end thereof being made integral with a pin 18 retained in a housing formed in an annular partition of the cover 11 c .
  • the shaft 12 crosses the bottom 11 a of the casing 11 by means of a seal 19 and, beyond this bottom, is joined by a flexible anti-vibration connection 20 to the shaft of an absolute encoder 21 mounted in an extension of the aforementioned background.
  • Fig. 4 illustrates a variant embodiment of the invention wherein it is the encoder 21 which is accommodated inside the drum 10, while the spring 17 is placed in a housing 22 reported laterally against the bottom 11a of the casing 11.
  • the mounting of this spring 17 is carried out in the same manner as in FIG. 3, in the sense that one of its ends is attached to a pin 16 secured to a socket 15 wedged on the shaft 12, while the pin 18 on which the opposite end moored is retained in the periphery of the housing 22.
  • the shaft 12 is supported by a bearing 11 d and a bearing 14, both mounted in the bottom 11 a of the housing 11.
  • the drum 10 which contains the encoder 21, linked by a flexible connection 20 to said shaft 12, is supported by two bearings 13 interposed between its inner face and the wall of a fixed bell or casing 23 fixed to the cover 11b of the casing 11.
  • the encoder 21 is here effectively protected from the external environment by virtue of its accommodation in the drum 10.
  • the drum 10, supported in rotation by two outer bearings 13, contains both the encoder 21 and the spring 17, arranged concentrically with respect to each other.
  • the shaft concentric with the drum 10, the spring 17 and the encoder 21 is constituted by a hollow cylindrical piece 12 'which, supported in rotation by the bottom 11 a and the cover 11 b of the casing 11 by means of a bearing 14, defines with the wall 10a of the drum an outer annular space containing the spring 17. in the interior of this part 12 'that is engaged the encoder 21 whose shaft is joined to said part by a flexible connector 20.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)

Description

La présente invention a trait aux vérins hydrauliques à double effet qui sont équipés d'un système d'asservissement propre à imposer à leur tige mobile une succession de déplacements conforme à une consigne programmable d'extensions et de contractions.The present invention relates to double-acting hydraulic cylinders which are fitted with a servo system capable of imposing on their movable rod a succession of displacements in accordance with a programmable setpoint of extensions and contractions.

Un tel vérin hydraulique à positionnement de tige asservi a été notamment décrit dans le document EP-A-0 305 306 (SDEM), auquel on pourra avantageusement se référer pour comprendre l'état actuel de la technique en la matière.Such a hydraulic cylinder with slaved rod positioning has been described in particular in document EP-A-0 305 306 (SDEM), which may advantageously be referred to in order to understand the current state of the art in the matter.

L'agencement général de ce type de vérin a été schématiquement rappelé en fig. 1 du dessin annexé aux présentes. Sur cette figure, la référence 1 désigne l'extrémité du cylindre fixe à l'intérieur duquel coulisse axialement le piston, la face arrière de ce dernier étant rendue solidaire d'un lien souple 2 à travers une attache à double articulation. L'extrémité opposée de ce lien 2 s'enroule dans une gorge hélicoïdale pratiquée dans la paroi d'un tambour d'entraînement 3. Celui-ci est calé sur un arbre transversal 4 qui, de part et d'autre dudit tambour, porte un codeur absolu 5 relié à un boîtier électronique de gestion, et un ressort spirale 6 pour le maintien constant sous tension du lien 22, lequel ressort est logé dans un boîtier 7 fixé latéralement au carter 8 qui supporte l'arbre 4.The general arrangement of this type of jack has been schematically recalled in FIG. 1 of the drawing appended hereto. In this figure, the reference 1 designates the end of the fixed cylinder inside which the piston slides axially, the rear face of the latter being made integral with a flexible link 2 through a double-articulated fastener. The opposite end of this link 2 is wound in a helical groove made in the wall of a drive drum 3. The latter is wedged on a transverse shaft 4 which, on either side of said drum, carries an absolute encoder 5 connected to an electronic management unit, and a spiral spring 6 for keeping the link 22 constant under tension, which spring is housed in a housing 7 fixed laterally to the casing 8 which supports the shaft 4.

L'expérience a démontré qu'un tel agencement permettait bien l'obtention d'un système d'asservissement robuste, parfaitement fiable et d'une précision très élevée. Il convient néanmoins d'observer que l'ensemble du système, avec les deux éléments entraînés (boîtier du ressort et codeur absolu) disposés en saillie de part et d'autre du tambour central d'entraînement, présente un encombrement important qui est de nature à gêner en certains cas son implantation en bout du cylindre 1 du vérin hydraulique. Par ailleurs, il arrive qu'un tel vérin asservi soit monté dans une ambiance polluée ou surchauffée, ou encore soumise à des champs magnétiques importants, ladite ambiance risquant de perturber le fonctionnement de l'un ou l'autre des éléments entraînés (ressort et codeur) qui sont associés au tambour d'entraînement.Experience has shown that such an arrangement makes it possible to obtain a robust, perfectly reliable and very high precision servo system. It should nevertheless be observed that the entire system, with the two driven elements (spring housing and absolute encoder) projecting on either side of the central drive drum, has a large size which is of a nature to hinder in some cases its location at the end of the cylinder 1 of the hydraulic cylinder. Furthermore, it sometimes happens that such a servo actuator is mounted in a polluted or overheated atmosphere, or else subjected to significant magnetic fields, said atmosphere being liable to disturb the operation of one or other of the driven elements (spring and encoder) which are associated with the drive drum.

C'est à ces inconvénients qu'entend remédier la présente invention, laquelle a pour objet le vérin hydraulique à positionnement de tige mobile asservi qui est défini à la revendication 1.It is to these drawbacks that the present invention intends to remedy, which relates to the hydraulic actuator with positioning of the movable moving rod which is defined in claim 1.

En fait l'invention consiste essentiellement à réaliser le tambour d'entraînement sous la forme d'une paroi cylindrique creuse pourvue d'un flasque transversal unique qui est décalé en direction de l'une des extrémités de ladite paroi, de manière à définir dans ledit tambour un espace libre apte à former logement pour l'un au moins des deux éléments entraînés qui lui sont associés.In fact, the invention essentially consists in producing the drive drum in the form of a hollow cylindrical wall provided with a single transverse flange which is offset in the direction of one of the ends of said wall, so as to define in said drum a free space capable of forming housing for at least one of the two driven elements associated with it.

Les dessins annexés, donnés à titre d'exemple, permettront de mieux comprendre l'invention, les caractéristiques qu'elle présente et les avantages qu'elle est susceptible de procurer :

  • Comme indiqué au début des présentes, fig. 1 est une coupe axiale rappelant l'agencement général d'un vérin à tige asservie réalisé conformément à la technique antérieure.
  • Fig. 2 est une vue en perspective montrant le tambour d'entraînement d'un vérin établi conformément à la présente invention.
  • Fig. 3, 4 et 5 sont des coupes axiales illustrant trois modes de mise en oeuvre différents de l'invention.
The appended drawings, given by way of example, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing:
  • As indicated at the beginning of this document, fig. 1 is an axial section recalling the general arrangement of an actuator with a slave rod produced in accordance with the prior art.
  • Fig. 2 is a perspective view showing the drive drum of a jack established in accordance with the present invention.
  • Fig. 3, 4 and 5 are axial sections illustrating three different embodiments of the invention.

En fig. 2, on a montré en 10 l'ensemble du tambour destiné à l'enroulement du lien souple 2 fixé à la face arrière du piston du vérin. Ce tambour 10 comprend une paroi cylindrique creuse 10a dont la surface extérieure est creusée d'une gorge 10b à profil hélicoïdal, tandis que sa surface intérieure se raccorde à un flasque transversal 10c percé axialement en 10d. Il est essentiel d'observer que ce flasque 10c est décalé par rapport au plan médian de la paroi cylindrique 10a, de façon à se trouver en fait disposé au niveau de l'un des bords de celle-ci.In fig. 2, the whole of the drum intended for winding the flexible link 2 fixed to the rear face of the piston of the jack has been shown at 10. This drum 10 comprises a hollow cylindrical wall 10 a whose outer surface is hollowed out by a groove 10 b with a helical profile, while its inner surface is connected to a transverse flange 10 c pierced axially at 10 d . It is essential to observe that this flange 10 c is offset with respect to the median plane of the cylindrical wall 10 a , so as to be in fact disposed at one of the edges thereof.

Dans le mode de mise en oeuvre de l'invention qui a été illustré en fig. 3, ce tambour 10 est fixé, à l'intérieur d'un carter 11, sur un arbre 12 introduit à travers son ouverture axiale 10d. Afin d'assurer un centrage rigoureux de ce tambour 10 en dépit de son montage en porte-à-faux sur l'arbre 12 lui-même monté en porte-à-faux sur le fond 11a du carter 11, la paroi cylindrique 10a coopère avec deux roulements 13 maintenus à l'intérieur du carter précité ; on a par ailleurs prévu un roulement de renfort 14 interposé entre un épaulement du couvercle 11b du carter 11 et l'extrémité d'une douille 15 clavetée sur l'arbre 12.In the embodiment of the invention which has been illustrated in FIG. 3, this drum 10 is fixed, inside a casing 11, on a shaft 12 introduced through its axial opening 10 d . In order to ensure rigorous centering of this drum 10 in spite of its cantilever mounting on the shaft 12 itself mounted in cantilever on the bottom 11 a of the casing 11, the cylindrical wall 10 a cooperates with two bearings 13 held inside the aforementioned casing; a reinforcement bearing 14 has also been provided interposed between a shoulder of the cover 11b of the casing 11 and the end of a socket 15 keyed onto the shaft 12.

Dans la paroi de la douille 15 est usiné un alésage longitudinal apte à recevoir une goupille 16 formant point d'amarrage pour l'une des extrémités d'un ressort spirale 17, l'extrémité opposée de celui-ci étant rendue solidaire d'une goupille 18 retenue dans un logement ménagé dans une cloison annulaire du couvercle 11c.In the wall of the sleeve 15 is machined a longitudinal bore capable of receiving a pin 16 forming a mooring point for one of the ends of a spiral spring 17, the opposite end thereof being made integral with a pin 18 retained in a housing formed in an annular partition of the cover 11 c .

L'arbre 12 traverse le fond 11a du carter 11 moyennant un joint 19 et, au-delà de ce fond, est réuni par un raccord flexible anti-vibration 20 à l'arbre d'un codeur absolu 21 monté dans un prolongement du fond précité.The shaft 12 crosses the bottom 11 a of the casing 11 by means of a seal 19 and, beyond this bottom, is joined by a flexible anti-vibration connection 20 to the shaft of an absolute encoder 21 mounted in an extension of the aforementioned background.

Le fonctionnement d'un tel vérin est identique à celui décrit dans le Brevet Français mentionné au début des présentes. On conçoit cependant que la disposition du ressort 17 à l'intérieur du logement défini par l'espace interne du tambour 10 réduit l'encombrement général et met ledit ressort à l'abri d'une ambiance polluée.The operation of such a jack is identical to that described in the French Patent mentioned at the beginning of this document. It is understood, however, that the arrangement of the spring 17 inside the housing defined by the internal space of the drum 10 reduces the overall dimensions and protects said spring from a polluted environment.

Fig. 4 illustre une variante de mise en oeuvre de l'invention dans laquelle c'est le codeur 21 qui est logé à l'intérieur du tambour 10, alors que le ressort 17 trouve place dans un boîtier 22 rapporté latéralement contre le fond 11a du carter 11. Le montage de ce ressort 17 est réalisé de la même manière qu'en fig. 3, en ce sens que l'une de ses extrémités est attachée à une goupille 16 solidaire d'une douille 15 calée sur l'arbre 12, tandis que la goupille 18 sur laquelle s'amarre l'extrémité opposée est retenue dans la périphérie du boîtier 22.Fig. 4 illustrates a variant embodiment of the invention wherein it is the encoder 21 which is accommodated inside the drum 10, while the spring 17 is placed in a housing 22 reported laterally against the bottom 11a of the casing 11. The mounting of this spring 17 is carried out in the same manner as in FIG. 3, in the sense that one of its ends is attached to a pin 16 secured to a socket 15 wedged on the shaft 12, while the pin 18 on which the opposite end moored is retained in the periphery of the housing 22.

L'arbre 12 est supporté par un palier 11d et un roulement 14, tous deux montés dans le fond 11a du carter 11. Le tambour 10 qui renferme le codeur 21, lié par un raccord flexible 20 audit arbre 12, est supporté par deux roulements 13 interposés entre sa face intérieure et la paroi d'une cloche fixe ou enveloppe 23 fixée au couvercle 11b du carter 11.The shaft 12 is supported by a bearing 11 d and a bearing 14, both mounted in the bottom 11 a of the housing 11. The drum 10 which contains the encoder 21, linked by a flexible connection 20 to said shaft 12, is supported by two bearings 13 interposed between its inner face and the wall of a fixed bell or casing 23 fixed to the cover 11b of the casing 11.

Le codeur 21 est ici efficacement protégé de l'ambiance extérieure par suite de son logement dans le tambour 10.The encoder 21 is here effectively protected from the external environment by virtue of its accommodation in the drum 10.

Enfin, dans la forme de réalisation suivant fig. 5, le tambour 10, supporté en rotation par deux roulements extérieurs 13, renferme à la fois le codeur 21 et le ressort 17, disposés concentriquement l'un par rapport à l'autre. L'arbre concentrique au tambour 10, au ressort 17 et au codeur 21 est constitué par une pièce cylindrique creuse 12' qui, supportée en rotation par le fond 11a et le couvercle 11b du carter 11 à l'aide d'un roulement 14, définit avec la paroi 10a du tambour un espace annulaire extérieur renfermant le ressort 17. C'est dans l'espace intérieur de cette pièce 12′ qu'est engagé le codeur 21 dont l'arbre est réuni à ladite pièce par un raccord flexible 20.Finally, in the embodiment according to fig. 5, the drum 10, supported in rotation by two outer bearings 13, contains both the encoder 21 and the spring 17, arranged concentrically with respect to each other. The shaft concentric with the drum 10, the spring 17 and the encoder 21 is constituted by a hollow cylindrical piece 12 'which, supported in rotation by the bottom 11 a and the cover 11 b of the casing 11 by means of a bearing 14, defines with the wall 10a of the drum an outer annular space containing the spring 17. in the interior of this part 12 'that is engaged the encoder 21 whose shaft is joined to said part by a flexible connector 20.

On obtient de la sorte un montage ramassé qui présente un encombrement très réduit et qui met à l'abri de l'ambiance extérieure aussi bien le ressort 17 que le codeur 21, et ce sans nuire en aucune façon à la robustesse de l'ensemble et à la précision du système d'asservissement.This results in a picked up assembly which has a very small footprint and which shelters from the outside environment both the spring 17 and the encoder 21, without in any way detracting from the robustness of the assembly. and the precision of the servo system.

Claims (4)

  1. Hydraulic actuator with automatically controlled positioning of a moving rod, of the sort comprising a shaft (12) which is oriented transversely to the axis of the cylinder (1) of the actuator and which carries three elements, namely a driving drum (10) connected by a flexible link (2) to the piston of the actuator, a flat spiral spring (17) for constantly keeping the said link under tension, and an absolute encoder (21) associated with an electronic management unit, characterized in that the drum (10) consists of a hollow cylindrical wall (10a) provided with a single transverse flange (10c) which is offset in the direction of one of the ends of the said cylindrical wall, so as to define within the said drum an empty space able to form a housing for at least one of the said other two driven elements (17, 21) which are associated with it.
  2. Actuator according to Claim 1, characterized in that one of the ends of the spring (17), housed in the drum (10), is anchored to an annular partition (11c) of the fixed casing (11) which carries the shaft (12), while the opposite end is rendered integral with a bushing (15) keyed onto the said shaft.
  3. Actuator according to Claim 1, characterized in that the shaft of the absolute encoder (21), housed in the drum (10), is connected to the shaft (12) by a flexible coupling (20), the body of the said encoder being enveloped inside a fixed bell housing (23) integral with the casing (11).
  4. Actuator according to Claim 1, characterized in that the shaft (12') is designed in the form of a tubular component so that it can define an external annular space between the opposing faces of the said tubular piece and of the drum (10), this space forming a housing for the spring (17), and an internal space forming a housing for the encoder (21).
EP19920420084 1991-03-22 1992-03-20 Hydraulic actuator with piston positioning means Expired - Lifetime EP0505297B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9103747A FR2674294B1 (en) 1991-03-22 1991-03-22 HYDRAULIC CYLINDER WITH MOVABLE ROD POSITIONING.
FR9103747 1991-03-22

Publications (2)

Publication Number Publication Date
EP0505297A1 EP0505297A1 (en) 1992-09-23
EP0505297B1 true EP0505297B1 (en) 1995-05-10

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Application Number Title Priority Date Filing Date
EP19920420084 Expired - Lifetime EP0505297B1 (en) 1991-03-22 1992-03-20 Hydraulic actuator with piston positioning means

Country Status (4)

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EP (1) EP0505297B1 (en)
DE (1) DE69202375T2 (en)
ES (1) ES2072120T3 (en)
FR (1) FR2674294B1 (en)

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Publication number Priority date Publication date Assignee Title
FR2741400B1 (en) * 1995-11-22 1998-01-09 Valeo HYDRAULIC CYLINDER PROVIDED WITH MEANS FOR DETECTING THE AXIAL POSITION OF ITS PISTON
US6234061B1 (en) 1998-10-20 2001-05-22 Control Products, Inc. Precision sensor for a hydraulic cylinder
US6694861B2 (en) 1998-10-19 2004-02-24 Control Products Inc. Precision sensor for a hydraulic cylinder
EP1443218B1 (en) * 1998-10-20 2007-01-03 Control Products Inc. Precision sensor for a hydraulic cylinder
FR2794196B1 (en) 1999-05-31 2002-04-26 Pierre Clavel DEVICE FOR MEASURING AND CONTINUOUSLY DISPLAYING THE POSITION OR POSITION CONTROL OF A CYLINDER ROD
US7093361B2 (en) 2002-01-23 2006-08-22 Control Products, Inc. Method of assembling an actuator with an internal sensor
US6866545B2 (en) 2003-03-10 2005-03-15 Control Products, Inc., (Us) Electrical cordset with integral signal conditioning circuitry
CN100359190C (en) * 2003-08-07 2008-01-02 北京欧特科新技术有限公司 Built-in hydraulic oil-cylinder displacement sensor
US7197974B2 (en) 2004-01-15 2007-04-03 Control Products Inc. Position sensor
US7609055B2 (en) 2004-07-21 2009-10-27 Control Products, Inc. Position sensing device and method
DE102005058178A1 (en) * 2005-12-05 2007-06-06 Sick Stegmann Gmbh locking device
CN107218267B (en) * 2017-06-01 2019-06-21 武汉船用机械有限责任公司 It is a kind of for detecting the device of hydraulic cylinder displacement

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US4969274A (en) * 1988-10-11 1990-11-13 Chang Fu Rong Displacement measuring and remote control apparatus with a sheave and a flexible belt

Also Published As

Publication number Publication date
FR2674294B1 (en) 1993-12-17
FR2674294A1 (en) 1992-09-25
ES2072120T3 (en) 1995-07-01
DE69202375D1 (en) 1995-06-14
DE69202375T2 (en) 1995-10-05
EP0505297A1 (en) 1992-09-23

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