WO2011138745A1 - Viscoelastic cylindrical shock absorber - Google Patents

Viscoelastic cylindrical shock absorber Download PDF

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Publication number
WO2011138745A1
WO2011138745A1 PCT/IB2011/051971 IB2011051971W WO2011138745A1 WO 2011138745 A1 WO2011138745 A1 WO 2011138745A1 IB 2011051971 W IB2011051971 W IB 2011051971W WO 2011138745 A1 WO2011138745 A1 WO 2011138745A1
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WO
WIPO (PCT)
Prior art keywords
cylindrical
viscoelastic
piece
axis
damper
Prior art date
Application number
PCT/IB2011/051971
Other languages
French (fr)
Inventor
Eduardo Beltran
Richard De Antonio
Thibaut Buffin
Original Assignee
Hutchinson
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Publication date
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Publication of WO2011138745A1 publication Critical patent/WO2011138745A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F1/00—Springs
    • F16F1/36—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers
    • F16F1/38—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers with a sleeve of elastic material between a rigid outer sleeve and a rigid inner sleeve or pin, i.e. bushing-type
    • F16F1/393—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers with a sleeve of elastic material between a rigid outer sleeve and a rigid inner sleeve or pin, i.e. bushing-type with spherical or conical sleeves
    • F16F1/3935—Conical sleeves

Definitions

  • the subject of the present invention is a viscoelastic rotary cylindrical damper providing insulation against vibrations and / or shocks, for example a drag damper for an articulated helicopter rotor or even a suspension rod, in particular for machines or for earthquake-resistant applications.
  • French patent application FR 2,818,717 discloses a cylindrical damper operating solely axially, since it is mounted on ball-ends 9, 10 which do not allow the torsional stress of the cylindrical damper and which make it possible to attaching to the connecting members of a rotor blade and a blade adjacent said rotor.
  • This concept requires, in order to function in the intended application, to provide sleeves of different lengths Li and L 2 and possibly to use different module viscoelastic materials so that the axial stiffness of the different viscoelastic sleeves is identical.
  • a viscoelastic cylindrical damper controlled by a connecting rod is known from US Patent Application 2009/110555. It consists of a bearing and a device providing stiffness and damping in rotation, which comprises planar or strongly conical stacks of viscoelastic disks working in torsion. The median plane of the discs is perpendicular to the axis of the damper bearing or forms a small angle with a plane perpendicular to the axis of the damper bearing. Damping is provided by the shearing of the layers due to the twisting movement around the axis of revolution, the stress (displacement and effort) being introduced by a connecting rod.
  • the flexibility of the layers in the direction of the force applied by the connecting rod imposes the use of a bearing between the two kinematic groups, in addition to the flat or strongly conical viscoelastic connection, in order to ensure the torsional movement while suppressing translation movements.
  • This bearing therefore aims to transfer, on the one hand, the radial forces minimizing as far as possible the radial displacements, and, on the other hand, to maintain the centering of the shock absorber during the rotational movements around the axis U z .
  • the invention proposes to simplify the concept while simultaneously ensuring the functions of stiffness, damping and bearing.
  • the present invention thus relates to a viscoelastic rotary cylindrical damper comprising an internal cylindrical piece having a cylindrical or conical outer contour and an outer cylindrical piece having a cylindrical or conical internal contour, these two cylindrical pieces having the same axis Uz, the external cylindrical part comprising a drive flange for fixing a connecting rod generating torsion movements around said axis Uz, characterized in that it comprises at least one viscoelastic element comprising at least one layer of cylindrical viscoelastic material or weakly conical coaxial with said cylindrical pieces and inclined with respect to the Uz axis of an angle ⁇ in absolute value between 0 ° and 45 ° and preferably between 0 ° and 30 °, the viscoelastic material having a damping coefficient tgô> 0.2 and preferably between 0.3 and 1, the rotary damper being devoid of an additional piece ensuring the bearing function.
  • This bearing function consists of taking up the forces passing through the connecting rod and ensuring control of the axis of rotation.
  • This cylindrical or conical arrangement makes the layer or layers have a radial stiffness sufficient to maintain the centering of the part, so that there is no longer need for an additional piece to ensure the sole bearing function.
  • the damper thus fulfills the functions of stiffness, damping and bearing.
  • the damper may comprise at least one laminated layer comprising at least one metal layer interposed between two said layers of viscoelastic material.
  • the damper may comprise at least two viscoelastic elements separated by an intermediate piece.
  • the damper is characterized in that it comprises at least one intermediate piece disposed between the inner cylindrical piece and the outer cylindrical piece and having an internal contour and a cylindrical or conical outer contour, and at least one said layer cylindrical viscoelastic or weakly conical between the outer contour of the inner part and the inner contour of the intermediate part on the one hand, and between the outer contour of the intermediate piece and the inner contour of the outer part of the other.
  • the damper may be characterized in that it comprises between the inner part and the intermediate piece and / or between the intermediate piece and the outer piece a laminated layer comprising at least one metal layer interposed between two said layers of viscoelastic material.
  • the damper may be characterized in that it comprises a first and a second set each of which comprises at least one said viscoelastic element, and which are offset axially along said axis Uz.
  • FIGS. 1a to 3c illustrate the operation of a drag damper of a drag articulation of a helicopter blade
  • FIG. 2 is a diagram of a rotary damper according to the invention
  • FIGS. 3 a and 3b show in perspective and in section an embodiment of a rotary cylindrical damper having a cylindrical laminated layer
  • FIGS. 4a and 4b are two perspective views of a rotary cylindrical damper according to the invention having two viscoelastic elements working in parallel for a higher stiffness in a limited space.
  • FIGS. 5a and 5b illustrate a variant in which the viscoelastic elements are split
  • FIGS. 6a to 6c illustrate a variant combining an addition of a layer in parallel and an axial resolution of the viscoelastic elements.
  • a flapping hinge 70 is connected by arms 71 to a drag hinge 72 connected to a blade 73 via a blade incidence control mechanism 74.
  • the joints 70 and 72 may actually be confused and the arm 71 is not imperative.
  • the rotary drag damper 75 has the function of damping the drag articulation 72 in rotation, as illustrated more particularly in FIGS. 1b and 1c, which show two positions of the blade in rotation around the drag articulation 72.
  • connecting rod 76 is articulated at 77 to the mechanism 74 and the drive flange 78 to the rotary drag damper 75 so as to pass thereto the drag rotation movements to be damped.
  • An attachment flange 79 serves to fix the damper to the structure.
  • FIGS. 1b and 1c show how the variations of the angular position of the mechanism 74 with respect to the arm 71 cause rotation of the rotary drag damper 75 via the connecting rod 76.
  • the rotation of the rotary damper of FIG. drag 75 is thus produced by the application of a force at one point of its perimeter.
  • a rotary damper according to the invention comprises a central piece 2 and an outer piece 1 between which are adhered the conical faces of an element 3 made of viscoelastic material having a damping coefficient tg0> 0.2 and more particularly between 0.3 and 1 for high damping.
  • the layers have a radial stiffness sufficient to define the axis of rotation of the part and resume the drive forces generated by the rod.
  • the viscoelastic material is, for example, silicone or polybutadiene.
  • the inner part 2 has a frustoconical outer contour 21 and the outer part 1 has a frustoconical inner contour 11.
  • the outer part 1 is generally a movable cylindrical armature, while the inner part 2 is a fixed cylindrical armature.
  • the angle ⁇ which defines the taper of the element 3 is less than or equal to 45 °, and in particular to 30 °. It is for example between 0 ° and 15 °, and preferably between 0 ° and 5 °.
  • the viscoelastic element 3 can also be cylindrical, as can the external and internal contours 21 and 11.
  • the viscoelastic element 3 may consist of a single layer of viscoelastic material.
  • the viscoelastic element 3 can be laminated one or more times.
  • One or more spacers 4 cylindrical or slightly conical with the same angle coaxial with the reinforcements allow this lamination.
  • FIGS. 3a and 3b illustrate the case of a cylindrical viscoelastic element 3 laminated once, and thus having a cylindrical spacer 4.
  • the interlayers 4 or are rigid, usually metal.
  • This abutment comprises a finger 5 secured (or made integral by a suitable assembly) of the inner part 2 and two protuberances 51 and 52 carried by the outer part 1.
  • the outer part 1 has two lugs 15 for attachment to a link 16 which is damped by the viscoelastic damping bearing.
  • each viscoelastic element performs both the function of stiffness, damping and bearing.
  • FIGS. 4a and 4b thus illustrate the case of a damper having two viscoelastic elements 31 and 32 operating in parallel and separated by a cylindrical intermediate element 6 having a cylindrical or slightly conical internal contour 62 and an outer contour 61 cylindrical or slightly conical with the same angle a.
  • the intermediate element 6 is ribbed or hollowed out (sectors 63) in order to reduce its mass, and the outer element 31 is laminated for example once.
  • one or the other of the viscoelastic elements 31 and 32 may be laminated with at least one metal insert 4, or not laminated, depending on the desired stiffness. This embodiment makes it possible to increase the stiffness while maintaining a limited space requirement.
  • FIG. 4b illustrates the damper with a driving element 7 of the inner part 2.
  • FIGS. 4a and 4b may also have a device for rotating stop as illustrated with FIGS. 2a and 2b.
  • This state can also be obtained by vulcanization of the viscoelastic material under high pressure, which in particular makes it possible to multiply the possible number of layers of the bearing and thus be able to adjust the value of stiffness with greater flexibility.
  • the invention makes it possible in all cases to avoid the addition of a conventional bearing whose sole function is to limit radial deformations.
  • the damper comprises two viscoelastic elements 33 and 34 axially offset along the Uz axis and each having a cylindrical or conical layer 3, which makes it possible to obtain a high stiffness by having a larger axial size.
  • An attachment flange 79 is integral with a central hub 80.
  • the drive flange 78 serves to attach a connecting rod such as the rod 76.
  • conical layers 3 it is preferred to have head-to-tail. layers that are axially offset.
  • FIGS. 6a to 6c combine the two previous embodiments by axially shifting along the Uz axis two groups of viscoelastic elements 31 and 32 on the one hand and 3 and 32 'on the other hand.
  • the fastening flange 79 is integral with the central hub 80 and the driving flange 78 serves for fastening a connecting rod such as 76.
  • the attachment of the rotary damper could be achieved other than by a flange such as 79.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Vibration Prevention Devices (AREA)

Abstract

The invention relates to a viscoelastic rotary cylindrical shock absorber which comprises an internal cylindrical part having a cylindrical or tapering outer contour and an outer cylindrical part having a cylindrical or tapering inner contour, said two cylindrical parts having the same axis Uz, the outer cylindrical part comprising a drive flange intended for attaching a crankshaft generating twisting movements about said axis Uz, characterised in that the shock absorber comprises at least one viscoelastic element including at least one cylindrical or slightly tapering layer of viscoelastic material (3) coaxial with said cylindrical parts (1, 2) and tilted relative to the axis Uz by an angle a with an absolute value of 0° to 45°, preferably between 0° and 30°, the viscoelastic material having a damping coefficient tgô > 0.2, preferably between 0.3 and 1, the rotary shock absorber lacking an additional part that performs the function of a bearing. Thus, the shock absorber simultaneously performs the functions of stiffener, shock absorber and bearing.

Description

AMORTISSEUR CYLINDRIQUE VISCOELASTIQUE.  VISCOELASTIC CYLINDRICAL SHOCK ABSORBER.
La présente invention a pour objet un amortisseur cylindrique rotatif viscoélastique assurant une isolation contre les vibrations et/ou les chocs, par exemple un amortisseur de traînée pour rotor articulé d'hélicoptère ou bien encore une bielle de suspension, notamment pour des machines ou pour des applications parasismiques.  The subject of the present invention is a viscoelastic rotary cylindrical damper providing insulation against vibrations and / or shocks, for example a drag damper for an articulated helicopter rotor or even a suspension rod, in particular for machines or for earthquake-resistant applications.
On connaît de la Demande de Brevet Français FR 2 818 717 un amortisseur cylindrique fonctionnant uniquement axialement, puisqu'il est monté sur des embouts à rotule 9, 10 qui ne permettent pas la sollicitation en torsion de l'amortisseur cylindrique et qui permettent de le rattacher à des organes de liaison d'une pale de rotor et d'une pale voisine dudit rotor. Ce concept nécessite, pour fonctionner dans l'application envisagée, de prévoir des manchons de longueurs Li et L2 différentes et éventuellement d'utiliser des matériaux viscoélastiques de modules différents pour que la raideur axiale des différents manchons viscoélastiques soit identique. French patent application FR 2,818,717 discloses a cylindrical damper operating solely axially, since it is mounted on ball-ends 9, 10 which do not allow the torsional stress of the cylindrical damper and which make it possible to attaching to the connecting members of a rotor blade and a blade adjacent said rotor. This concept requires, in order to function in the intended application, to provide sleeves of different lengths Li and L 2 and possibly to use different module viscoelastic materials so that the axial stiffness of the different viscoelastic sleeves is identical.
Un amortisseur cylindrique viscoélastique commandé par une bielle est connu de la Demande de Brevet US 2009/110555. Il est constitué d'un palier et d'un dispositif assurant une raideur et un amortissement en rotation, lequel comporte des empilements plans ou fortement coniques de disques viscoélastiques travaillant en torsion. Le plan médian des disques est perpendiculaire à l'axe du palier de l'amortisseur ou forme un angle faible avec un plan perpendiculaire à l'axe du palier de l'amortisseur. L'amortissement est apporté par le cisaillement des couches dû au mouvement de torsion autour de l'axe de révolution, la sollicitation (déplacement et effort) étant introduite par une bielle. La souplesse des couches dans la direction de l'effort appliqué par la bielle impose l'utilisation d'un palier entre les deux groupes cinématiques, en supplément de la liaison viscoélastique plane ou fortement conique, afin d'assurer le mouvement de torsion tout en supprimant les mouvements de translation. Ce palier a donc pour but de transférer, d'une part, les efforts radiaux en minimisant dans la mesure du possible les déplacements radiaux, et, d'autre part, de conserver le centrage de l'amortisseur lors des mouvements de rotation autour de l'axe Uz. A viscoelastic cylindrical damper controlled by a connecting rod is known from US Patent Application 2009/110555. It consists of a bearing and a device providing stiffness and damping in rotation, which comprises planar or strongly conical stacks of viscoelastic disks working in torsion. The median plane of the discs is perpendicular to the axis of the damper bearing or forms a small angle with a plane perpendicular to the axis of the damper bearing. Damping is provided by the shearing of the layers due to the twisting movement around the axis of revolution, the stress (displacement and effort) being introduced by a connecting rod. The flexibility of the layers in the direction of the force applied by the connecting rod imposes the use of a bearing between the two kinematic groups, in addition to the flat or strongly conical viscoelastic connection, in order to ensure the torsional movement while suppressing translation movements. This bearing therefore aims to transfer, on the one hand, the radial forces minimizing as far as possible the radial displacements, and, on the other hand, to maintain the centering of the shock absorber during the rotational movements around the axis U z .
L'invention propose de simplifier le concept en assurant simultanément les fonctions de raideur, d'amortissement et de palier.  The invention proposes to simplify the concept while simultaneously ensuring the functions of stiffness, damping and bearing.
La présente invention concerne ainsi un amortisseur cylindrique rotatif viscoélastique comportant une pièce cylindrique interne ayant un contour externe cylindrique ou conique et une pièce cylindrique externe ayant un contour interne cylindrique ou conique, ces deux pièces cylindriques ayant un même axe Uz, la pièce cylindrique externe comportant une bride d'entraînement destinée à la fixation d'une bielle générant des mouvements de torsion autour dudit axe Uz,caractérisé en ce qu'il comporte au moins un élément viscoélastique comprenant au moins une couche de matériau viscoélastique cylindrique ou faiblement conique coaxiale auxdites pièces cylindriques et inclinés par rapport à l'axe Uz d'un angle a compris en valeur absolue entre 0° et 45° et de préférence entre 0° et 30°, le matériau viscoélastique ayant un coefficient d'amortissement tgô > 0,2 et de préférence compris entre 0.3 et 1, l'amortisseur rotatif étant dépourvu d'une pièce supplémentaire assurant la fonction de palier. Cette fonction de palier consiste à reprendre les efforts transitant par la bielle et à assurer la maîtrise de l'axe de rotation. The present invention thus relates to a viscoelastic rotary cylindrical damper comprising an internal cylindrical piece having a cylindrical or conical outer contour and an outer cylindrical piece having a cylindrical or conical internal contour, these two cylindrical pieces having the same axis Uz, the external cylindrical part comprising a drive flange for fixing a connecting rod generating torsion movements around said axis Uz, characterized in that it comprises at least one viscoelastic element comprising at least one layer of cylindrical viscoelastic material or weakly conical coaxial with said cylindrical pieces and inclined with respect to the Uz axis of an angle α in absolute value between 0 ° and 45 ° and preferably between 0 ° and 30 °, the viscoelastic material having a damping coefficient tgô> 0.2 and preferably between 0.3 and 1, the rotary damper being devoid of an additional piece ensuring the bearing function. This bearing function consists of taking up the forces passing through the connecting rod and ensuring control of the axis of rotation.
Cette disposition cylindrique ou conique fait que le ou les couches présentent une raideur radiale suffisante pour maintenir le centrage de la pièce, ce qui fait qu'il n'est plus besoin d'une pièce supplémentaire pour assurer la seule fonction de palier. L'amortisseur remplit ainsi les fonctions de raideur, d'amortissement et de palier.  This cylindrical or conical arrangement makes the layer or layers have a radial stiffness sufficient to maintain the centering of the part, so that there is no longer need for an additional piece to ensure the sole bearing function. The damper thus fulfills the functions of stiffness, damping and bearing.
L'amortisseur peut comporter au moins une couche lamifiée comprenant au moins une couche métallique interposée entre deux dites couches en matériau viscoélastique.  The damper may comprise at least one laminated layer comprising at least one metal layer interposed between two said layers of viscoelastic material.
L'amortisseur peut comporter aux moins deux éléments viscoélastiques séparées par une pièce intermédiaire. A cet effet, l'amortisseur est caractérisé en ce qu'il comporte au moins une pièce intermédiaire disposée entre la pièce cylindrique interne et la pièce cylindrique externe et ayant un contour interne et un contour externe cylindriques ou coniques, et au moins une dite couche viscoélastique cylindrique ou faiblement conique entre le contour externe de la pièce interne et le contour interne de la pièce intermédiaire d'une part, et entre le contour externe de la pièce intermédiaire et le contour interne de la pièce externe d'autre part.  The damper may comprise at least two viscoelastic elements separated by an intermediate piece. For this purpose, the damper is characterized in that it comprises at least one intermediate piece disposed between the inner cylindrical piece and the outer cylindrical piece and having an internal contour and a cylindrical or conical outer contour, and at least one said layer cylindrical viscoelastic or weakly conical between the outer contour of the inner part and the inner contour of the intermediate part on the one hand, and between the outer contour of the intermediate piece and the inner contour of the outer part of the other.
L'amortisseur peut être caractérisé en ce qu'il comporte entre la pièce interne et la pièce intermédiaire et/ou entre la pièce intermédiaire et la pièce externe une couche lamifiée comprenant au moins une couche métallique interposée entre deux dites couches en matériau viscoélastique.  The damper may be characterized in that it comprises between the inner part and the intermediate piece and / or between the intermediate piece and the outer piece a laminated layer comprising at least one metal layer interposed between two said layers of viscoelastic material.
L'amortisseur peut être caractérisé en ce qu'il comporte un premier et un deuxième ensemble dont chacun comporte au moins un dit élément viscoélastique, et qui sont décalés axialement selon ledit axe Uz.  The damper may be characterized in that it comprises a first and a second set each of which comprises at least one said viscoelastic element, and which are offset axially along said axis Uz.
D'autres caractéristiques et avantages de l'invention apparaîtront mieux à la lecture de la description ci-après, en liaison avec les dessins annexés : les figures la à le illustrent le fonctionnement d'un amortisseur de traînée d'une articulation de traînée d'une pale d'hélicoptère Other features and advantages of the invention will appear better on reading the description below, in conjunction with the appended drawings: FIGS. 1a to 3c illustrate the operation of a drag damper of a drag articulation of a helicopter blade
la figure 2 est un schéma d'un amortisseur rotatif selon l'invention  FIG. 2 is a diagram of a rotary damper according to the invention
- les figures 3 a et 3b montrent en perspective et en coupe un mode de réalisation d'un amortisseur cylindrique rotatif ayant une couche lamifiée cylindrique  FIGS. 3 a and 3b show in perspective and in section an embodiment of a rotary cylindrical damper having a cylindrical laminated layer
les figures 4a et 4b sont deux vues en perspective d'un amortisseur cylindrique rotatif selon l'invention ayant deux éléments viscoélastiques travaillant en parallèle pour une raideur plus élevée dans un encombrement limité les figures 5a et 5b illustrent une variante dans laquelle les éléments viscoélastiques sont dédoublés  FIGS. 4a and 4b are two perspective views of a rotary cylindrical damper according to the invention having two viscoelastic elements working in parallel for a higher stiffness in a limited space. FIGS. 5a and 5b illustrate a variant in which the viscoelastic elements are split
et les figures 6a à 6c illustrent une variante combinant un ajout d'une couche en parallèle et d'un dédoublement axial des éléments viscoélastiques.  and FIGS. 6a to 6c illustrate a variant combining an addition of a layer in parallel and an axial resolution of the viscoelastic elements.
Les figures la à le montrent l'articulation d'une pale d'hélicoptère 73 à un arbre rotor 7.  Figures la to show the articulation of a helicopter blade 73 to a rotor shaft 7.
Une articulation de battement 70 est reliée par des bras 71 à une articulation de traînée 72 reliée à une pale 73 par l'intermédiaire d'un mécanisme 74 de commande d'incidence de la pale. Les articulations 70 et 72 peuvent en réalité être confondues et le bras 71 n'est donc pas impératif.  A flapping hinge 70 is connected by arms 71 to a drag hinge 72 connected to a blade 73 via a blade incidence control mechanism 74. The joints 70 and 72 may actually be confused and the arm 71 is not imperative.
L'amortisseur rotatif de traînée 75 a pour fonction d'amortir en rotation l'articulation de traînée 72, comme illustré plus particulièrement aux figures lb et le qui montrent deux positions de la pale en rotation autour de l'articulation de traînée 72. Une bielle 76 est articulée en 77 au mécanisme 74 et par la bride d'entraînement 78 à l'amortisseur rotatif de traînée 75 de manière à répercuter vers celui-ci les mouvements de rotation de traînée à amortir. Une bride de fixation 79 permet de fixer l'amortisseur à la structure. On voit aux figures lb et le comment les variations de la position angulaire du mécanisme 74 par rapport au bras 71 entraînent la rotation de l'amortisseur rotatif de traînée 75 par l'intermédiaire de la bielle 76. La rotation de l'amortisseur rotatif de traînée 75 est ainsi produite par l'application d'un effort en un point de son périmètre.  The rotary drag damper 75 has the function of damping the drag articulation 72 in rotation, as illustrated more particularly in FIGS. 1b and 1c, which show two positions of the blade in rotation around the drag articulation 72. connecting rod 76 is articulated at 77 to the mechanism 74 and the drive flange 78 to the rotary drag damper 75 so as to pass thereto the drag rotation movements to be damped. An attachment flange 79 serves to fix the damper to the structure. FIGS. 1b and 1c show how the variations of the angular position of the mechanism 74 with respect to the arm 71 cause rotation of the rotary drag damper 75 via the connecting rod 76. The rotation of the rotary damper of FIG. drag 75 is thus produced by the application of a force at one point of its perimeter.
Comme illustré à la figure 2, un amortisseur rotatif selon l'invention comporte une pièce centrale 2 et une pièce extérieure 1 entre lesquelles sont adhérisées les faces coniques d'un élément 3 en matériau viscoélastique ayant un coefficient d'amortissement tgô > 0,2, et plus particulièrement comprise entre 0,3 et 1 pour un amortissement élevé. De la sorte, les couches ont une raideur radiale suffisante pour définir l'axe de rotation de la pièce et reprendre les efforts d'entraînement générés par la bielle. As illustrated in FIG. 2, a rotary damper according to the invention comprises a central piece 2 and an outer piece 1 between which are adhered the conical faces of an element 3 made of viscoelastic material having a damping coefficient tg0> 0.2 and more particularly between 0.3 and 1 for high damping. In this way, the layers have a radial stiffness sufficient to define the axis of rotation of the part and resume the drive forces generated by the rod.
Le matériau viscoélastique est par exemple du silicone ou du polybutadiène. La pièce interne 2 présente un contour externe tronconique 21 et la pièce externe 1 présente un contour interne tronconique 11.  The viscoelastic material is, for example, silicone or polybutadiene. The inner part 2 has a frustoconical outer contour 21 and the outer part 1 has a frustoconical inner contour 11.
La pièce externe 1 constitue en général une armature cylindrique mobile, alors que la pièce interne 2 constitue une armature cylindrique fixe.  The outer part 1 is generally a movable cylindrical armature, while the inner part 2 is a fixed cylindrical armature.
L'angle a qui définit la conicité de l'élément 3 est inférieur ou égal à 45°, et en particulier à 30°. Il est par exemple compris entre 0° et 15°, et de préférence entre 0° et 5°.  The angle α which defines the taper of the element 3 is less than or equal to 45 °, and in particular to 30 °. It is for example between 0 ° and 15 °, and preferably between 0 ° and 5 °.
L'élément viscoélastique 3 peut être également cylindrique, de même que les contours externes 21 et interne 11.  The viscoelastic element 3 can also be cylindrical, as can the external and internal contours 21 and 11.
Cette disposition cylindrique ou conique fait que la ou les couches présentent une raideur radiale suffisante pour maintenir le centrage de la pièce, ce qui fait que la mise en œuvre d'une pièce supplémentaire pour assurer la seule fonction de palier n'est plus nécessaire.  This cylindrical or conical arrangement that the layer or layers have sufficient radial stiffness to maintain the centering of the workpiece, so that the implementation of an additional piece to ensure the sole bearing function is no longer necessary.
L'élément viscoélastique 3 peut être constitué d'une simple couche de matériau viscoélastique.  The viscoelastic element 3 may consist of a single layer of viscoelastic material.
Pour augmenter la raideur radiale suivant un axe radial, l'élément viscoélastique 3 peut être lamifié une ou plusieurs fois.  To increase the radial stiffness along a radial axis, the viscoelastic element 3 can be laminated one or more times.
Un ou plusieurs intercalaires 4 cylindriques ou faiblement coniques avec le même angle a coaxiaux avec les armatures permettent de réaliser cette lamification.  One or more spacers 4 cylindrical or slightly conical with the same angle coaxial with the reinforcements allow this lamination.
Les figures 3a et 3b illustrent le cas d'un élément viscoélastique 3 cylindrique lamifié une fois, et présentant donc un intercalaire 4 cylindrique.  FIGS. 3a and 3b illustrate the case of a cylindrical viscoelastic element 3 laminated once, and thus having a cylindrical spacer 4.
Le ou les intercalaires 4 sont rigides, généralement en métal.  The interlayers 4 or are rigid, usually metal.
On notera la présente d'une butée bi-directionnelle limitant l'amplitude des mouvements de rotation.  Note the presence of a bi-directional stop limiting the amplitude of the rotational movements.
Cette butée comporte un doigt 5 solidaire (ou rendu solidaire par un montage adapté) de la pièce interne 2 et deux excroissances 51 et 52 portées par la pièce externe 1.  This abutment comprises a finger 5 secured (or made integral by a suitable assembly) of the inner part 2 and two protuberances 51 and 52 carried by the outer part 1.
La pièce externe 1 présente deux pattes 15 de fixation à une biellette 16 qui est amortie par le palier-amortisseur viscoélastique.  The outer part 1 has two lugs 15 for attachment to a link 16 which is damped by the viscoelastic damping bearing.
Pour augmenter la raideur radiale et bénéficier de davantage de raideur de rotation autour de l'axe Uz, on peut utiliser plusieurs éléments viscoélastiques 3 travaillant en parallèle, sans adjonction d'un élément faisant fonction de palier. Chaque élément viscoélastique remplit à la fois la fonction de raideur, d'amortisseur et de palier. To increase the radial stiffness and to benefit from more stiffness of rotation around the Uz axis, it is possible to use several viscoelastic elements 3 working in parallel, without the addition of a functioning element. bearing. Each viscoelastic element performs both the function of stiffness, damping and bearing.
Les figures 4a et 4b illustrent ainsi le cas d'un amortisseur ayant deux éléments viscoélastiques 31 et 32 fonctionnant en parallèle et séparés par un élément intermédiaire cylindrique 6 ayant un contour interne 62 cylindrique ou faiblement conique et un contour externe 61 cylindrique ou faiblement conique avec le même angle a. Dans l'exemple représenté, l'élément intermédiaire 6 est nervuré ou évidé (secteurs 63) afin d'en réduire la masse, et l'élément extérieur 31 est lamifié par exemple une fois. On notera que l'un ou l'autre des éléments viscoélastiques 31 et 32 peuvent être lamifiés avec au moins un insert métallique 4, ou non lamifiés, en fonction de la raideur souhaitée. Ce mode de réalisation permet d'augmenter la raideur tout en maintenant un encombrement limité.  FIGS. 4a and 4b thus illustrate the case of a damper having two viscoelastic elements 31 and 32 operating in parallel and separated by a cylindrical intermediate element 6 having a cylindrical or slightly conical internal contour 62 and an outer contour 61 cylindrical or slightly conical with the same angle a. In the example shown, the intermediate element 6 is ribbed or hollowed out (sectors 63) in order to reduce its mass, and the outer element 31 is laminated for example once. It will be noted that one or the other of the viscoelastic elements 31 and 32 may be laminated with at least one metal insert 4, or not laminated, depending on the desired stiffness. This embodiment makes it possible to increase the stiffness while maintaining a limited space requirement.
La figure 4b illustre l'amortisseur avec un élément 7 d'entraînement de la pièce interne 2.  FIG. 4b illustrates the damper with a driving element 7 of the inner part 2.
Les modes de réalisation des figures 4a et 4b peuvent également présenter un dispositif de butée en rotation comme illustré avec les figures 2a et 2b.  The embodiments of FIGS. 4a and 4b may also have a device for rotating stop as illustrated with FIGS. 2a and 2b.
Pour optimiser la raideur radiale, il est souhaitable d'éliminer les contraintes résiduelles de traction dans le matériau viscoélastique. Ces contraintes résiduelles de traction sont issues du retrait généré lors de la phase de refroidissement menant de la température de vulcanisation à la température ambiante.  To optimize the radial stiffness, it is desirable to eliminate the residual tensile stresses in the viscoelastic material. These residual tensile stresses result from the shrinkage generated during the cooling phase leading from the vulcanization temperature to room temperature.
Pour éliminer ces contraintes résiduelles de traction, on peut mettre en œuvre de manière connue en soi, une pré-contrainte axiale par dudgeormage sur la bague intérieure 2, et/ou un rétreint sur la bague extérieure 1.  To eliminate these residual tensile stresses, it is possible to implement, in a manner known per se, an axial pre-stress by degewing on the inner ring 2, and / or a necking on the outer ring 1.
On peut aussi obtenir cet état par vulcanisation du matériau viscoélastique sous haute pression, ce qui permet notamment de multiplier le nombre possible de couches du palier et de pouvoir ainsi régler avec plus de flexibilité la valeur des raideurs.  This state can also be obtained by vulcanization of the viscoelastic material under high pressure, which in particular makes it possible to multiply the possible number of layers of the bearing and thus be able to adjust the value of stiffness with greater flexibility.
L'invention permet dans tous les cas d'éviter l'ajout d'un palier classique dont la seule fonction est de limiter les déformations radiales.  The invention makes it possible in all cases to avoid the addition of a conventional bearing whose sole function is to limit radial deformations.
Dans le mode de réalisation des figures 5a et 5b, l'amortisseur comporte deux éléments viscoélastiques 33 et 34 décalés axialement selon l'axe Uz et comportant chacun une couche cylindrique ou conique 3, ce qui permet d'obtenir une raideur élevée en disposant d'un encombrement axial plus important. Une bride de fixation 79 est solidaire d'un moyeu central 80. La bride d'entraînement 78 sert à la fixation d'une bielle telle que la bielle 76. Dans le cas des couches 3 coniques, il est préféré de disposer tête-bêche les couches qui sont décalées axialement. Les figures 6a à 6c combinent les deux modes de réalisation précédents en décalant axialement selon l'axe Uz deux groupes d'éléments viscoélastiques 31 et 32 d'une part et 3 et 32' d'autre part. Comme dans le cas des figures 5a et 5b, la bride de fixation 79 est solidaire du moyeu central 80 et la bride d'entraînement 78 sert à la fixation d'une bielle telle que 76. In the embodiment of FIGS. 5a and 5b, the damper comprises two viscoelastic elements 33 and 34 axially offset along the Uz axis and each having a cylindrical or conical layer 3, which makes it possible to obtain a high stiffness by having a larger axial size. An attachment flange 79 is integral with a central hub 80. The drive flange 78 serves to attach a connecting rod such as the rod 76. In the case of conical layers 3, it is preferred to have head-to-tail. layers that are axially offset. FIGS. 6a to 6c combine the two previous embodiments by axially shifting along the Uz axis two groups of viscoelastic elements 31 and 32 on the one hand and 3 and 32 'on the other hand. As in the case of FIGS. 5a and 5b, the fastening flange 79 is integral with the central hub 80 and the driving flange 78 serves for fastening a connecting rod such as 76.
Dans tous les cas, la fixation de l'amortisseur rotatif pourrait être réalisée autrement que par une bride telle que 79.  In all cases, the attachment of the rotary damper could be achieved other than by a flange such as 79.

Claims

REVENDICATIONS
1) Amortisseur cylindrique rotatif viscoélastique comportant une pièce cylindrique interne ayant un contour externe cylindrique ou conique et une pièce cylindrique externe ayant un contour interne cylindrique ou conique, ces deux pièces cylindriques ayant un même axe Uz, la pièce cylindrique externe comportant une bride d'entraînement destinée à la fixation d'une bielle générant des mouvements de torsion autour dudit axe Uz, caractérisé en ce qu'il comporte au moins un élément viscoélastique comprenant au moins une couche (3) de matériau viscoélastique cylindrique ou faiblement conique coaxiale auxdites pièces cylindriques (1, 2) et inclinés par rapport à l'axe Uz d'un angle a compris en valeur absolue entre 0° et 45°, et de préférence entre 0° et 30°, le matériau viscoélastique ayant un coefficient d'amortissement tgô > 0,2 et de préférence compris entre 0.3 et 1, l'amortisseur rotatif étant dépourvu d'une pièce supplémentaire assurant la fonction de palier.  1) viscoelastic rotary cylindrical damper comprising an inner cylindrical piece having a cylindrical or conical outer contour and an outer cylindrical piece having a cylindrical or conical inner contour, these two cylindrical pieces having a same axis Uz, the outer cylindrical piece having a flange of drive for fixing a connecting rod generating torsion movements about said axis Uz, characterized in that it comprises at least one viscoelastic element comprising at least one layer (3) of viscoelastic material cylindrical or slightly conical coaxial with said cylindrical parts (1, 2) and inclined with respect to the axis Uz of an angle α in absolute value between 0 ° and 45 °, and preferably between 0 ° and 30 °, the viscoelastic material having a damping coefficient tgô > 0.2 and preferably between 0.3 and 1, the rotary damper being devoid of an additional piece providing the function of he landing.
2) Amortisseur selon la revendication 1, caractérisé en ce que l'élément viscoélastique comporte une couche lamifiée comprenant au moins un insert métallique (4) délimitant deux dites couches (3) en matériau viscoélastique.  2) Damper according to claim 1, characterized in that the viscoelastic element comprises a laminated layer comprising at least one metal insert (4) defining two said layers (3) of viscoelastic material.
3) Amortisseur selon la revendication 1, caractérisé en ce qu'il comporte au moins une pièce intermédiaire (6) disposée entre la pièce cylindrique interne (2) et la pièce cylindrique externe (1) et ayant un contour interne (62) et un contour externe (61) cylindriques ou coniques, et au moins une dite couche (3) viscoélastique cylindrique ou faiblement conique entre le contour externe (21) de la pièce interne (1) et le contour interne (62) de la pièce intermédiaire (6) d'une part, et entre le contour externe (61) de la pièce intermédiaire (6) et le contour interne (11) de la pièce externe (1) d'autre part.  3) damper according to claim 1, characterized in that it comprises at least one intermediate piece (6) disposed between the inner cylindrical piece (2) and the outer cylindrical piece (1) and having an inner contour (62) and a outer contour (61) cylindrical or conical, and at least one said viscoelastic layer (3) cylindrical or slightly conical between the outer contour (21) of the inner part (1) and the inner contour (62) of the intermediate piece (6) ) on the one hand, and between the outer contour (61) of the intermediate piece (6) and the inner contour (11) of the outer piece (1) on the other hand.
4) Amortisseur selon la revendication 3, caractérisé en ce qu'il comporte entre la pièce interne (2) et la pièce intermédiaire (6) et/ou entre la pièce intermédiaire (6) et la pièce externe (1) une couche lamifiée comprenant au moins une couche métallique (4) entre deux dites couches (3) en matériau viscoélastique.  4) Damper according to claim 3, characterized in that it comprises between the inner part (2) and the intermediate piece (6) and / or between the intermediate piece (6) and the outer piece (1) a laminated layer comprising at least one metal layer (4) between two said layers (3) of viscoelastic material.
5) Amortisseur selon l'une des revendications précédentes, caractérisé en ce qu'il comporte un premier et un deuxième ensemble dont chacun comporte au moins un dit élément viscoélastique (31, 32, 3 Γ, 32', 33, 34), et qui sont décalés axialement selon ledit axe Uz.  5) Damper according to one of the preceding claims, characterized in that it comprises a first and a second set each of which comprises at least one said viscoelastic member (31, 32, 3 Γ, 32 ', 33, 34), and which are offset axially along said axis Uz.
PCT/IB2011/051971 2010-05-06 2011-05-04 Viscoelastic cylindrical shock absorber WO2011138745A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1001959 2010-05-06
FR1001959A FR2959790B1 (en) 2010-05-06 2010-05-06 VISCOELASTIC CYLINDRICAL SHOCK ABSORBER.

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2050235A1 (en) * 1969-07-04 1971-04-02 Sud Aviation Expanded polystyrene shock absorbant - instrument mounting for space craft
FR2818717A1 (en) 2000-12-26 2002-06-28 Eurocopter France Elastic shock absorbing coupling e.g. for helicopter rotor blades has viscoelastic sleeves between inner, outer and intermediate rigid cylinders
US20090110555A1 (en) 2007-09-04 2009-04-30 Peter Jones Helicopter aircraft vehicle rotor damper

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2050235A1 (en) * 1969-07-04 1971-04-02 Sud Aviation Expanded polystyrene shock absorbant - instrument mounting for space craft
FR2818717A1 (en) 2000-12-26 2002-06-28 Eurocopter France Elastic shock absorbing coupling e.g. for helicopter rotor blades has viscoelastic sleeves between inner, outer and intermediate rigid cylinders
US20090110555A1 (en) 2007-09-04 2009-04-30 Peter Jones Helicopter aircraft vehicle rotor damper

Also Published As

Publication number Publication date
FR2959790B1 (en) 2013-04-26
FR2959790A1 (en) 2011-11-11

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