ACOUSTIC INSULATION DEVICE FOR AUTOMOTIVE GLAZING

Abstract

The present invention relates to a device for the acoustic insulation of a plate, preferably automotive glazing, comprising an acoustic insulation portion and a mounting portion, the mounting portion being configured to be fixedly mounted on an edge of the plate, the mounting portion being fixedly mounted to the acoustic insulation portion, the acoustic insulation portion comprising an acoustic black hole. Figure for the abstract: Fig. 2

Description

Title of the invention: ACOUSTIC INSULATION DEVICE FOR AUTOMOTIVE GLAZING FIELD OF INVENTION

[0001] The present invention relates to the sound insulation of glazing for a motor vehicle, and more particularly to the sound insulation of a side window. PRIOR TECHNOLOGY

[0002] Vehicle glazing is subjected to airborne noise during vehicle use. The transmission of this noise through the glazing degrades the acoustic comfort of a user.

[0003] It is known to increase the surface mass of the glazing by increasing its thickness to improve the acoustic insulation of the glazing.

[0004] However, such glazing does not effectively increase sound insulation for frequencies above 2000 hertz. Indeed, the coincidence between the frequency of an incident sound wave and the frequency of the bending waves in the glazing leads to a decrease in sound insulation for this frequency range. Furthermore, the design of a motor vehicle requires weight reduction of the various vehicle components in order to decrease the vehicle's energy consumption and CO2 emissions during operation.

[0005] With reference to [Fig. 1], document EP 0844075 B1 describes laminated glazing comprising two sheets of mineral glass 6, the two sheets of glass 6 being separated by a first layer of polyvinyl butyral 14 (acronym PVB), an interlayer film 15 of acoustic acrylic polymer, and a second layer of polyvinyl butyral 14. This glazing is referred to by those skilled in the art as “acoustic PVB glazing”. Such glazing makes it possible to increase sound insulation in a frequency range between 2000 Hz and 20000 Hz.

[0006] However, such glazing entails high manufacturing costs. Furthermore, its manufacture can be complex compared to other known glazing. Therefore, such glazing is generally not chosen as side glazing for vehicles. Description of the invention

[0007] An object of the invention is to propose a solution to enable a glazing to have acoustic insulation greater than or equal to that of a known glazing, at least in a range of audible frequencies, while limiting the costs associated with the manufacture of such glazing.

[0008] This objective is achieved within the framework of the present invention by means of a device for the acoustic insulation of a plate, comprising an acoustic insulation portion and a assembly part, - the mounting part being configured to be fixedly mounted on an edge of the plate, the mounting part being fixedly mounted to the acoustic insulation part and having a second thickness h 2 in contact with the acoustic insulation part, - the acoustic insulation part being formed of a first material, and extending along a first length l in a first principal direction, the acoustic insulation part having a first thickness h; of the first material in a direction perpendicular to the first principal direction, the first thickness h, varying, as a function of a coordinate x, along the first length / proportionally to a value of xn, where n is a real number strictly greater than 1, from a minimum thickness h lmin up to the second thickness h 2, the first length / being predetermined so that the minimum thickness h Imin is less than or equal to one third of the second thickness h 2.

[0009] The present invention is advantageously complemented by the following features, taken individually or in any of their technically possible combinations:

[0010] - n is a real number greater than or equal to 5 / 3 and preferably greater than or equal to 2, - n is strictly less than 100, - the device includes a side edge, and the sound insulation part forms a thinning of the device from the mounting part to the side edge, n being preferably a real number greater than or equal to 2, - the acoustic insulation part has at least one recess in the first material and n is preferably a real number greater than or equal to 5 / 3, - the hollow has an elliptical and preferably circular shape, - an opening is formed in the center of the recess, - the device includes a viscoelastic heat sink, the heat sink being fixedly mounted in contact with at least part of the acoustic insulation, the heat sink being formed from a material having a first loss factor i]; strictly greater than 0.05, in particular strictly greater than 0.10, and preferably strictly greater than 0.15, - the mounting part forms a housing suitable for receiving an edge of the plate.

[0011] Another aspect of the invention is an assembly comprising a device according to an embodiment of the invention, and a plate having an edge, the mounting part being fixedly mounted on the edge of the plate.

[0012] Advantageously, the first material has a real part E' of the first Young's modulus, a first density p, and a first Poisson's ratio v, and the mounting part has a first phase velocity component y. bending wave defined by / E h ~ \1 / 4 the plate having a third thickness h 3 , a part '' 1 = ( 12p,(l - v s 2 ) ) real E'2 of the second Young's modulus, a second density p2 and a second Poisson's ratio v2, defining a second phase velocity component y2 of a bending wave defined by / £ h - \1 the difference between the first component yj and between the ''2 = second component y 2 being less than 20% of the second component y 2, and preferably being less than 10% of the second component y 2.

[0013] Advantageously, the plate is a glazing.

[0014] Advantageously, the glazing comprises at least one sheet of mineral glass.

[0015] Advantageously, the glazing is laminated glazing.

[0016] Advantageously, the plate is a glazing comprising a sheet of mineral glass, and the material of the device includes aluminium, the second thickness h 2 being equal to the third thickness h 3.

[0017] Advantageously, the plate is a glazing comprising a sheet of mineral glass, and the material of the device comprises a polymer material, the second thickness h 2 being strictly greater than the third thickness h 3.

[0018] Another aspect of the invention is a method for manufacturing an assembly comprising a device according to an embodiment of the invention, and a plate having an edge, the method comprising a step of fixing the mounting part on an edge of the plate. DESCRIPTION OF THE FIGURES

[0019] Other features, objectives and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0020] [fig. 1] - the [fig. 1] schematically illustrates a known glazing exhibiting acoustic insulation properties,

[0021] [fig.2] - Fig.2 schematically illustrates a cross-section of a device according to a mode of the embodiment of the invention, in which the device exhibits a thinning from a mounting part of the device to a lateral edge of the device,

[0022] [fig.3] - the [fig.3] schematically illustrates a cross-section of a device according to an embodiment of the invention, in which the device has a thinning from a mounting part of the device to a lateral edge of the device,

[0023] [fig.4] - [fig.4] schematically illustrates a cross-section of a device according to a mode of the realization of the invention, the device having a recess,

[0024] [fig.5] - the [fig.5] schematically illustrates a hollowing out of a device according to a top view embodiment of the invention,

[0025] [fig.6] - Fig.6 schematically illustrates an assembly according to one embodiment of the invention, comprising a device and a plate, the device being fixedly mounted to the plate,

[0026] [fig.7] - Fig.7 schematically illustrates an assembly according to one embodiment of the invention, comprising a device and a plate, the device being fixedly mounted to the plate,

[0027] [fig.8] - Fig.8 schematically illustrates a side window of a vehicle a mobile home according to an embodiment of the invention,

[0028] [fig.9] - Fig.9 schematically illustrates a side window of a vehicle a mobile home according to an embodiment of the invention,

[0029] [fig.10] - the [fig.10] is a diagram illustrating an average of the acceleration of known glazing and assemblies according to embodiments of the invention, depending on the frequency of an incident acoustic wave,

[0030] [fig.ll] - the [fig.ll] is a diagram illustrating acoustic insulation of a known glazing and assemblies according to embodiments of the invention.

[0031] Throughout the figures, similar elements bear identical reference numerals. DEFINITIONS

[0032] The term “loss factor rj” of a material, the material having a complex Young’s modulus E, is understood to be the ratio between the imaginary part E” of the Young’s modulus of the material, associated with the elasticity of the material, and the real part E’ of the Young’s modulus of the material, associated with the viscosity of the material.

[0033] The loss factor rj of a material, also designated “tan ô”, is defined by the international standard ISO 18437-2:2005 (Mechanical vibration and shock—Characterization of the dynamic mechanical properties of viscoelastic materials — Part 2: Resonance method, part 3.2).

[0034] Preferably, the loss factor rj can be defined for a predetermined frequency. In the present context, "a material has a first loss factor rj greater than a value" means that the material has a first loss factor rj greater than the value for each of the frequencies in the audible frequency range, that is to say in a frequency range extending between 20 Hz inclusive and 20,000 Hz inclusive, and preferably between 20 Hz inclusive and 10,000 Hz inclusive.

[0035] The loss factor rj can be defined for a predetermined temperature. The temperature range considered in the present invention is between -20°C and 60°C. In the present invention, "a material has a first loss factor greater than a value" means that the material has a first loss factor rj greater than the value for each of the temperatures between -20°C and 60°C.

[0036] The term "the real part E' of the Young's modulus of a material is greater than a value" means that the real part E' of the Young's modulus of the material is greater than the real part E' of the Young's modulus of the material for each of the frequencies in the audible frequency range, that is to say in a frequency range extending between 20 Hz inclusive and 20,000 Hz inclusive, and preferably between 20 Hz inclusive and 10,000 Hz inclusive.

[0037] The real part E' and the imaginary part E” of Young's modulus can be defined for a predetermined temperature. The temperature range considered in the present invention is between -20°C and 60°C. In this invention, "the real part E' of Young's modulus of a material is greater than a certain value" means that the material has a real part E' of Young's modulus greater than the certain value for each of the temperatures between -20°C and 60°C. In this invention, "a material has a first loss factor rj greater than a certain value" means that the material has a first loss factor rj greater than the certain value for each of the temperatures between -20°C and 60°C.

[0038] A dynamic characterization of a material is performed on a Metravib-type viscoanalyzer under the following measurement conditions. A sinusoidal load is applied to the material. A measurement sample of the material to be measured consists of two rectangular parallelepipeds, each parallelepiped having a thickness of 3.31 mm, a height of 10.38 mm, and a width of 6.44 mm. Each parallelepiped formed by the material is also referred to as a shear specimen. The excitation is implemented with a dynamic amplitude of 5 pm around the rest position, traversing the frequency range from 5 Hz to 700 Hz, and traversing a temperature range from -20°C to +60°C.

[0039] The viscoanalyzer allows each specimen (each sample) to be subjected to deformations under precise temperature and frequency conditions, and the displacements of the specimen, the forces applied to the specimen and their phase shift to be measured, which makes it possible to measure rheological quantities characterizing the material of the specimen.

[0040] The exploitation of the measurements makes it possible in particular to calculate the Young's modulus E of the material, and particularly the real part E' of the Young's modulus and the imaginary part E” of the Young's modulus of the material, and thus to calculate the tangent of the loss angle (or loss factor) rj (also designated by tan 0).

[0041] A value of the real part E' of Young's modulus and / or a loss factor rj of a material are measured without the material being prestressed.

[0042] The term "glazing" means a structure comprising at least one sheet of organic or mineral glass, preferably adapted for mounting in a vehicle, pre- referencing a motor vehicle.

[0043] The glazing may comprise a single sheet of glass or a multi-layered glazed assembly of which at least one layer is a sheet of glass.

[0044] A glazing unit may comprise a glazing assembly. The glazing assembly comprises at least one sheet of glass. The glass may be organic or mineral glass. The glass may be tempered. The glazing assembly is preferably laminated glazing. "Laminated glazing" is defined as a glazing assembly comprising at least two sheets of glass and an interlayer film made of plastic, preferably viscoelastic, separating the two sheets of glass. The plastic interlayer film may comprise one or more layers of a viscoelastic polymer such as poly(vinyl butyral) (PVB) or an ethylene-vinyl acetate (EVA) copolymer. The interlayer film is preferably made of standard PVB or acoustic PVB (such as single-layer or triple-layer acoustic PVB).Acoustic PVB can consist of three layers: two outer layers of standard PVB and an inner layer of PVB with added plasticizer to make it less rigid than the outer layers.

[0045] An “ellipse” is defined as a closed plane curve obtained by the intersection of a right circular cone with a plane, provided that the plane intersects the axis of rotation of the cone or cylinder. The ellipse is a conic section with an eccentricity strictly between 0 and 1. The ellipse is also the locus of points whose sum of distances to two fixed points, called foci, is constant. DETAILED DESCRIPTION OF THE INVENTION

[0046] General architecture and theoretical elements

[0047] With reference to [fig.2], [fig.3], and [fig.4], a device 1 for the acoustic insulation of a plate 4 comprises an acoustic insulation part 2 and a mounting part 3.

[0048] The mounting part 3 is fixedly mounted to the acoustic insulation part 2. Preferably, the mounting part 3 and the acoustic insulation part 2 form a single monolithic piece made of the same first material. The mounting part 3 has a second thickness h 2 in contact with the acoustic insulation part 2. The device 1 extends along a principal direction 6. Preferably, the thickness of the mounting part 3 is constant and equal to the second thickness h 2 along the principal direction 6.

[0049] The mounting part 3 is configured to be fixedly mounted on an edge of the plate 4. The edge of the plate can be a slice of the plate 4. The edge of the plate can be perpendicular to the main direction 6, so that the main direction 6 is parallel to a surface along which the plate 4 extends.

[0050] The acoustic insulation portion 2 is formed by the first material. The portion Acoustic insulation portion 2 extends along a first length l in the first principal direction 6. The acoustic insulation portion 2 has a first thickness h of the first material, in a direction perpendicular to the first principal direction 6. The first thickness h varies, as a function of a coordinate x, along the first length l proportionally to a value of xn, where n is a real number strictly greater than 1, from a minimum thickness h lmin to the second thickness A2, the first length l being predetermined such that the minimum thickness h Imin is less than or equal to one-third of the second thickness h2. The coordinate x is equal to zero when the thickness h of the acoustic insulation portion 2 is equal to h2min. When the coordinate x is equal to the first length l, the thickness hi of the acoustic insulation portion 2 is equal to the thickness h2 of the mounting portion 3.

[0051] Thus, the device 1 allows the reception of bending waves propagating from the edge of the plate 4 without reflecting them towards the plate 4. When the plate 4 is exposed to an incident acoustic wave, the propagating bending waves, once transmitted to the device 1, first in the mounting part 3 and then in the acoustic insulation part 2. The acoustic insulation part 2 prevents the reflection of the bending waves into the device 1, which makes it possible to acoustically isolate the plate 4 when the device 1 is fixedly mounted on the plate 4.

[0052] Indeed, as described in the document Mironov et al. (Mironov, MA, 1988, “Propagation of a flexural wave in a plate whose thickness decreases smoothly to zero in afinite interval”, Soviet Physics Acoustics-USSR, 34(3), 318-319), a decrease in the thickness of a thin plate at its edges can make the edges non-reflective for flexural waves in the plate material, when the decrease follows a power law, so that the thickness h of the plate is proportional to xn, where n is a real number strictly greater than 1.

[0053] The first thickness h of the acoustic insulation part 2 can be defined by the following formula (1):

[0054] h , (x) = e.xn (1)

[0055] where e is a proportionality factor.

[0056] The phase velocity cbI of the bending waves in the acoustic insulation part 2 can be defined as a function of the thickness h; (x) of the acoustic insulation part by the following formula (2):

[0057] JeW'» 2 V' 4|2 > l ' M ] Hpjl-v, 2 )]

[0058] where E'i is the real part of the Young's modulus of the first material, g² is the density of the first material, v is the Poisson's ratio of the first material, h is (x) is the thickness of the acoustic insulation part at the x coordinate and co is the angular frequency of the incident acoustic wave.

[0059] From the phase velocity cbI in the acoustic insulation section 2, a transit time of a bending wave propagating in the acoustic insulation zone 11 can be calculated. When the thickness hImin tends towards zero, the transit time tends towards infinity. Thus, the incident bending wave is not reflected by the acoustic insulation section 2, which increases the acoustic insulation of the plate 4.

[0060] The term “acoustic black hole” refers to the acoustic insulation portion 2. The device 1 comprises at least one acoustic black hole. The device 1 may also comprise a plurality, and preferably an array, of acoustic black holes.

[0061] In practice, it is not possible to manufacture a thickness hImin of zero. The inventors discovered that the sound insulation effect appears when the first length l is predetermined such that the minimum thickness hlmin is less than or equal to one-third of the second thickness h2. In particular, the first length l is predetermined such that the minimum thickness h2 mm is less than or equal to one-fifth of the second thickness h2. More preferably, the first length l is predetermined such that the minimum thickness hlmin is less than or equal to one-tenth of the second thickness h2.

[0062] The inventors also discovered that the sound insulation effect appears for n strictly greater than 1, in particular greater than or equal to 5 / 3, and preferably greater than or equal to 2. In addition, n can be strictly less than 100, so as to avoid a reflection at the junction between the sound insulation part 2 and the mounting part 3. The sound insulation part 2 can have, along a second principal direction 16, a size greater than or equal to the first length l, the second principal direction 16 being locally perpendicular to the first principal direction 6 and perpendicular to a direction along which the thickness of the device 1 locally extends.

[0063] Acoustic insulation part 2

[0064] With reference to [Fig. 2] and [Fig. 3], the device 1 may include a side edge 9, the sound insulation portion 2 forming a taper of the device 1 from the mounting portion 3 to the side edge 9. Preferably, n is a real number greater than or equal to 2. The sound insulation portion 2 thus forms a blade or edge extending along the second principal direction 16. This makes it possible to facilitate the manufacture of the device 1, while still allowing the sound insulation of a plate 4. Preferably, the sound insulation portion 2 extending along the second principal direction 16 over a length greater than or equal to the first length 1.

[0065] With reference to [Fig. 4], the acoustic insulation portion 2 may have at least one recess 7. Preferably, n is a real number greater than or equal to 5 / 3. Preferably, the recess 7 has a minimum size Wmin, depending on the surface area in which the plate 4 extends, greater than or equal to the first length 1. The recess 7 may have an elliptical shape, and preferably a circular shape. An ellipse formed by the recess 7 may have a minimum radius rmin. Preferably, the minimum radius rmin of the ellipse is greater than or equal to the first length 1. The recess 7 may also have a square or rectangular shape.

[0066] With reference to [Fig. 4] and [Fig. 5], an opening 17 can be formed in the center of the recess 7. Thus, a part of acoustic insulation 2 having the minimum thickness hlmin can be manufactured so that the minimum thickness hlmin is as close as possible to zero thickness, which makes it possible to minimize the reflection of a bending wave propagating in the device 1 and thus to increase the acoustic insulation of the plate 4. Preferably, when the recess has an elliptical shape, the first length 1 is greater than the difference between the radius r or the minimum radius rmin of the recess 7 and the radius of the opening.

[0067] The sound insulation portion 2 can have different shapes. The first material can form an edge at the lateral border 9 of the sound insulation portion 2. Alternatively, the material can have a fork-shaped cross-section, with the sound insulation portion 2 forming two edges at the border of the sound insulation portion 2. The first thickness h can, in this case, be measured by adding the thicknesses of each of the fork's branches. The material can form a recess 7. The material can also form a cavity. In this case, the first thickness h of the sound insulation portion 2 is measured by adding the thicknesses of the material forming the cavity. The sound insulation portion 2 can also extend along a curved surface.In this case, the measurement of the first thickness h of the acoustic insulation part 2 is implemented by measuring the thickness of the material along a direction locally perpendicular to the curved surface.

[0068] Viscoelastic heat sink 8

[0069] With reference to [Fig. 2], [Fig. 3], and [Fig. 4], the device 1 may include a viscoelastic heat sink 8. The heat sink 8 may be fixedly mounted in contact with at least a portion of the acoustic insulation zone 11. The heat sink 8 may be made of a material having a first loss factor ql strictly greater than 0.05, in particular strictly greater than 0.10, and preferably strictly greater than 0.15. Thus, the energy concentrated in an acoustic insulation zone 11 by incident bending waves is dissipated viscously, thereby reducing the reflection of a bending wave in the device 1 and thus preventing the emission of waves bending in plate 4 by reflection in device 1. The material of the heat sink 8 is viscoelastic, and can have a real part E' of Young's modulus less than 100 MPa, and preferably less than 10 MPa.

[0070] With reference to [Fig. 2], [Fig. 3], and [Fig. 4], the heat sink 8 can be fixedly mounted on a portion of the acoustic insulation zone 11 having a thickness between hlmin and h2 / 2. Thus, the bending waves are dissipated by the heat sink 8 at the point where they are most concentrated. Preferably, a portion of the heat sink 8 is in contact with the acoustic insulation portion 2 having the minimum thickness hlmin.

[0071] The heat sink 8 can be formed from a material selected from silicone, nitrile, and polyurethane. The viscoelastic properties of known materials can be measured by the methods described herein. The heat sink material can have a glass transition temperature between -80°C and -50°C inclusive. For example, the heat sink material can comprise methyl vinyl silicone (MVQ) crosslinked with benzoyl peroxide. The heat sink material can also be a porous material. The loss factor of the material can also be adjusted by a tackifying agent, for example, a glycerin ester, calcium carbonate, or carbon nanotubes. For example, Weber's Weberseal PU 40 polyurethane sealant (registered trademark) has a loss factor of 0.41 and an imaginary part E' value of Young's modulus of 7.2 MPa.For example, Sikaflex PRO-11 FC polyurethane sealant (registered trademark) from the Sika brand has a loss factor / / equal to 0.20 and a value of the imaginary part E' of Young's modulus equal to 1.2 MPa.

[0072] Assembly part 3

[0073] With reference to [fig.6] and [fig.7], the mounting part 3 is configured to be fixedly mounted on an edge 11 of the plate 4. The mounting part 3 includes a termination suitable for being fixedly mounted on the edge 11.

[0074] The mounting portion 3 can form a housing 10 suitable for receiving the edge 11 of the plate 4. The housing 10 can form a clamp configured to surround the edge 11. Thus, the housing 10 can be in contact with an edge of the plate 4 and simultaneously with an upper and a lower face of the plate 4. Therefore, the device 1 can be fixedly mounted to the plate 4 without any rotational or translational degrees of freedom relative to the plate 4. This configuration allows for the efficient transmission of bending waves from the plate 4 to the device 1. An end of the mounting portion 3 can also be bonded to the edge 11. The mounting portion 3 can also be configured to be fixedly and removably mounted to the plate 4.

[0075] Set 13

[0076] An assembly 13 comprises a device 1 and a plate 4 having an edge 11, in which the mounting part 3 is fixedly mounted on the edge 11 of the plate 4. The plate 4 has a third thickness h 3 at the edge 11. The third thickness h 3 is preferably constant in the plate 4.

[0077] One aspect of the invention is a method for manufacturing the assembly 13. The method includes a step of fixing the mounting part 3 onto an edge of the plate 4. Preferably, the mounting part 3 can be recessed, clipped or removably mounted on the edge of the plate 4. The mounting part 3 can also be glued to the edge of the plate 4. The glue can be chosen from at least one single- or multi-component structural adhesive, such as epoxy, methacrylate, polyurethane, acrylic, or vinyl.

[0078] Preferably, the difference between a first phase velocity cb of the bending waves in the mounting part 3 and between a second phase velocity ch2 of the bending waves in the plate 4 is less than 20% of the second phase velocity c, and preferably is less than 10% of the second phase velocity ch2 when the plate 4 is exposed to an acoustic wave of determined pulsation co.

[0079] The first phase velocity c hi of the bending waves in the mounting part 3 is defined by the following formula (3):

[0080] Ch^ yx.wU2 (3)

[0081] where co is a pulsation of the acoustic wave incident on the plate 4, and yi is a first phase velocity component defined by the following formula (4):

[0082] U2p,(l-vr)

[0083] where E' i is the real part of the first Young's modulus of the first material, q ; is a first density of the first material, and v 7 a first Poisson's ratio of the first material.

[0084] The second phase velocity c h2 of the bending waves in the plate 4 is defined by the following formula (5):

[0085] cb2 = (5)

[0086] where co is a pulsation of the acoustic wave incident on the plate 4, and y2 is a first phase velocity component defined by the following formula (4):

[0087] , 1 (6) E2hE r F 2- (12^(1-^) /

[0088] where E' 2 is the real part of the second Young's modulus of the material of plate 4, q 2 is a second density of the material of plate 4, and v 2 is a second Poisson's ratio of the material of plate 4.

[0089] The relationship described above between the phase velocities of the bending waves can thus be expressed as follows: the difference between the first component y; and between the second component y 2 is less than 20% of the second component y 2, and preferably is less than 10% of the second component y 2 ■ Thus, the reflection of a bending wave propagating from the plate 4 towards the device 1 can be limited or cancelled.

[0090] Preferably, the plate 4 is a glazing unit 12. Machining a glazing unit 12 is a complex and costly operation. In particular, machining an acoustic black hole can be complex, especially due to the profile of the acoustic insulation portion 2 of the acoustic black hole. Thus, it is possible to improve the acoustic insulation of the glazing unit 12 by mounting it fixed to a device 1, without having to machine the glazing unit 12. Preferably, the glazing unit 12 comprises at least one sheet of mineral glass. Indeed, a sheet of mineral glass may be required in many types of glazing units 12, although it is difficult to machine. The glazing unit 12 may be laminated or monolithic.

[0091] When the glazing 12 comprises a sheet of mineral glass, the first material can be aluminum, and the second thickness h2 is equal to the third thickness h3. Indeed, the real part of Young's modulus E', the Poisson's ratio v7, and the density q of aluminum allow, in relation to the real part of Young's modulus E'2, the Poisson's ratio v2, and the density q2 of the mineral glass, verification of the relationship between the first component y7 and the second component y2 for a second thickness h2 equal to a third thickness h3. Thus, it is possible to manufacture a device 1 in aluminum and thereby facilitate the machining of the acoustic black hole(s) while limiting the increase in the mass of the assembly 13.

[0092] When the glazing 12 comprises a sheet of mineral glass, the first material can be a polymer material, preferably resin, and the second thickness h2 is strictly greater than the third thickness h3. Indeed, the real part of Young's modulus E', the Poisson's ratio v7, and the density q of the polymer materials allow, with regard to the real part of Young's modulus E'2, the Poisson's ratio v2, and the density q2 of the mineral glass, verification of the relationship between the first component y1 and the second component y2 for a second thickness h2 strictly greater than a third thickness h3. Thus, it is possible to fabricate a device 1 in a first polymer material and thereby facilitate the machining of the acoustic black hole(s), while limiting the increase in the mass of the assembly 13.

[0093] Plate 4 can also be chosen from a ceiling and a partition, preferably a gypsum partition. Thus, it is possible to improve the sound insulation of a ceiling or a partition without modifying them.

[0094] With reference to [Fig. 8] and [Fig. 9], the glazing 12 may be a side window 12 of a motor vehicle. Preferably, the assembly 13 includes means for attaching it to a door of the motor vehicle, such that the device 1 is arranged in the door outside the belt portion when the assembly 13 is attached to the door. In this case, the device 1 is configured to be arranged under a door seal. With reference to [Fig. 8], the sound insulation portion 2 may form a taper of the device 1 from the mounting portion 3 to the side edge 9. With reference to [Fig. 9], the sound insulation portion 2 may include a grid of recesses 7 in the first material.

[0095] Figure 10 illustrates the average acceleration of a glazing unit 12 along a direction corresponding to the thickness of the glazing unit 12, as a function of the frequency of an acoustic wave incident on the glazing unit 12. The glazing unit 12 is made of mineral glass. The glazing unit 12 has a thickness h3 of 4 mm, a length along the principal direction 6 of 300 mm, and a width of 60 mm. Curve (a) illustrates an average acceleration of the glazing 12 in the absence of device 1. Curve (b) illustrates an average acceleration of the glazing 12, the glazing 12 being fixedly mounted to a device 1 according to an embodiment of the invention, made of resin, in the absence of a heat sink 8. Curve (c) illustrates an average acceleration of the glazing 12, the glazing 12 being fixedly mounted to a device 1 according to an embodiment of the invention, made of resin, comprising a heat sink 8.

[0096] Figure 11 illustrates a numerical simulation using the finite element method of the sound insulation of a glazing unit 12, as a function of the frequency of an incident acoustic wave. Curve (d) illustrates the sound insulation of a laminated glazing unit 12, comprising a damping layer with a loss factor of 1%, in the absence of a device 1. Curve (e) illustrates the sound insulation of a laminated glazing unit 12, comprising a damping layer with a loss factor of 15%, in the absence of a device 1. Curve (f) illustrates the sound insulation of a laminated glazing unit 12, comprising a damping layer with a loss factor of 1%, the glazing unit 12 being fixedly mounted to an aluminum device 1. Curve (g) illustrates the acoustic insulation of a laminated glazing 12, comprising a damping layer with a loss factor of 1%, the glazing 12 being fixedly mounted to a resin device 1.

Claims

Demands

1. Device (1) for the acoustic insulation of a plate (4), comprising an acoustic insulation part (2) and a mounting part (3), the device being characterized in that: - the mounting part (3) is configured to be fixedly mounted on an edge (11) of the plate (4), the mounting part (3) being fixedly mounted to the acoustic insulation part (2) and having a second thickness h 2 in contact with the acoustic insulation part (2), - the acoustic insulation part (2) is formed of a first material, and extends along a first length l in a first principal direction (6), the acoustic insulation part (2) having a first thickness h;of the first material in a direction perpendicular to the first principal direction (6), the first thickness h, varying, as a function of a coordinate x, along the first length / proportionally to a value of xn, where n is a real number strictly greater than 1, from a minimum thickness h lmin to the second thickness h 2, the first length / being predetermined so that the minimum thickness h Imin is less than or equal to one third of the second thickness h 2.;

2. Device (1) according to the preceding claim, the device comprising a side border (9), in which the sound insulation part (2) forms a thinning of the device (1) from the mounting part (3) to the side border (9), and in which n is preferably a real number greater than or equal to 2.

3. Device (1) according to any one of the preceding claims, wherein the sound insulation part (2) has at least one recess (7) in the first material, and n is preferably a real number greater than or equal to 5 / 3, an opening (17) being preferably formed at the center of the recess (7).

4. Device (1) according to any one of the preceding claims, comprising a viscoelastic heat sink (8), in which the heat sink (8) is fixedly mounted in contact with at least a part of the acoustic insulation part (2), the heat sink (8) being formed of a material having a first loss factor / / ; strictly greater than 0.05, in particular strictly greater than 0.10, and preferably strictly greater than 0.

15.

5. Device according to any one of the preceding claims, in which the mounting part (3) forms a housing (10) suitable for receiving an edge (11) of the plate (4).

6. Assembly (13) comprising a device (1) according to any one of claims 1 to 5, and a plate (4) having an edge (11), in which the mounting part (3) is fixedly mounted on the edge (11) of the plate (4).

7. Assembly (13) according to claim 6, wherein the first material has a real part of the first Young's modulus E'j, a first density p7, and a first Poisson's ratio v;, and wherein the mounting part (3) has a first component y; of phase velocity of a bending wave defined by / E h-.2 \1 and wherein the plate (4) has a third thickness h3, a real part of the second Young's modulus E'2, a second density p2 and a second Poisson's ratio v2, defining a second component y2 of phase velocity of a bending wave defined by / E Jl2 \1 / 4 and wherein the difference between the first component y; and between the second component y2 is less than 20% of the second component y2, and preferably is less than 10% of the second component y2.

8. Assembly (13) according to claim 6 or 7, wherein the plate (4) is a glazing (12).

9. Assembly (13) according to claim 8, wherein the glazing (12) comprises at least one sheet of mineral glass.

10. Assembly (13) according to claim 9, wherein the glazing (12) is laminated glazing.

11. Assembly (13) according to any one of claims 6 to 10, wherein the plate (4) is a glazing (12) comprising a sheet of mineral glass, and wherein the material of the device (1) comprises aluminum, the second thickness h 2 being equal to the third thickness h 3.

12. Assembly (13) according to any one of claims 6 to 10, wherein the plate (4) is a glazing (12) comprising a mineral glass sheet, and wherein the material of the device (1) comprises a polymer material, the second thickness h 2 being strictly greater than the third thickness h 3.

13. Method of manufacturing an assembly (13) comprising a device (1) according to any one of claims 1 to 5, and a plate (4) having an edge (11), the method comprising a step of fixing the mounting part (3) onto an edge of the plate (4).

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