Acoustic attenuation device

Abstract

The invention relates to an acoustic attenuation member (10), in particular configured to be assembled in an acoustic attenuation device (1) mounted on an air inlet (100) of a motor vehicle, the acoustic attenuation member (10) comprising a cavity (11) and a neck (12) communicating with the cavity (11), the acoustic attenuation member (10) being formed by two separate parts (20, 30) which are assembled, one of the parts (20) forming at least the bottom of the cavity (11) and the other part (30) forming the neck (12).

Description

Description Title of the invention: Acoustic attenuation device

[0001] The invention relates to a sound attenuation device configured to be mounted in a ventilation, heating and / or air conditioning system of a motor vehicle which includes such a sound attenuation device or in a front panel module of a motor vehicle which includes the sound attenuation device, as well as a ventilation, heating and / or air conditioning system of a motor vehicle which includes such a sound attenuation device and a front panel module of a motor vehicle which includes the sound attenuation device.

[0002] Generally, a motor vehicle includes an air intake in the form of an opening located on the front of the vehicle. The incoming air is used to facilitate heat exchange between the vehicle and its cooling system, which is located near the front of the vehicle. More specifically, the air entering the engine compartment is guided by ducts to the cooling system to allow heat exchange between the incoming air and the heat exchanger of the cooling system. It is important to minimize airflow losses between the air intake and the heat exchanger.Indeed, any airflow entering the vehicle and escaping towards the engine compartment before contributing to heat exchange inside the vehicle negatively influences the air resistance coefficient of said vehicle.

[0003] It is known to use air ducts, typically made of plastic or other flexible material, connecting the air intake to the cooling system. When air flows through these ducts, particularly when the cooling system's fan is activated to cool the batteries in an electric vehicle, noise is generated. This is because the acoustic waves produced by the fan travel along the air duct and radiate outwards towards the front of the vehicle.

[0004] To address this, it is known to equip these air ducts with at least one acoustic attenuation device to reduce the acoustic energy propagating through them and thus decrease the noise radiated from the ducts, particularly during electric vehicle charging. To reduce acoustic waves, this type of acoustic attenuation device includes a resonator of Helmholtz allows the acoustic energy radiated from the front of the vehicle to be reduced at a given frequency.

[0005] A Helmholtz resonator typically comprises a cavity and a neck connecting the cavity to an air duct oriented perpendicular to the airflow direction. The interaction between the airflow and the resonator's neck can cause acoustic disturbances and generate secondary noise, particularly whistling, which degrades the performance of the acoustic attenuation device incorporating resonators. The resonator then loses effectiveness or even becomes a source of noise.

[0006] In this context, the present invention proposes an acoustic attenuation device that can be manufactured in a relatively simple manner.

[0007] The invention relates in particular to an acoustic attenuation element, in particular configured to be assembled in an acoustic attenuation device mounted on an air intake of a motor vehicle, the acoustic attenuation element comprising a cavity and a neck communicating with the cavity, the acoustic attenuation element being formed by two separate parts which are assembled, one of the parts forming at least a bottom of the cavity and the other part forming the neck.

[0008] According to one aspect of the invention, the two parts are molded parts, in particular made of plastic, in particular by injection molding of a plastic material. The plastic material is, for example, polypropylene.

[0009] The invention allows the manufacture of a closed cavity (except for the neck) by two molded and assembled plastic pieces.

[0010] According to one aspect of the invention, the cavity is formed entirely on one of the parts, and the other part, in particular in the form of a plate, which forms the neck, is configured to close the cavity by leaving the neck opening into the cavity.

[0011] In this case, the axial dimension (or length) of the neck corresponds to the thickness of the plate (or part) that defines the neck. Specifically, the neck is formed by a hole in the plate.

[0012] Alternatively, the cavity is formed entirely on one of the pieces which includes the neck, and the other of the pieces, notably in the form of a plate, defines the bottom of the cavity.

[0013] Alternatively, the cavity is formed partly on one of the pieces which includes the neck, and partly on the other piece which defines the bottom of the cavity.

[0014] According to one aspect of the invention, at least one of the two parts includes a sealing gasket, in particular compressible, configured to ensure sealing at the interface of the junction of the two parts.

[0015] According to one aspect of the invention, the sealing gasket is overmolded onto the material of the corresponding part.

[0016] Thus, the part with the sealing gasket is of a bi-material type, with one material to form the part, notably injection-molded plastic, and another material for form the sealing joint. The joint is, for example, of the elastomer type, for example of SEBS material.

[0017] Airtightness at the interface where the two parts meet is necessary to prevent air leaks that could generate unwanted noise and degrade the acoustic performance of the sound attenuation device.

[0018] According to one aspect of the invention, the part forming the neck has at least one groove and the sealing gasket extends at least partially into this groove.

[0019] The groove(s) on the surface of the part forming the neck allow the sealing material to be channeled during injection into the manufacturing mold.

[0020] According to one aspect of the invention, the groove or grooves are formed by molding the part forming the neck.

[0021] According to one aspect of the invention, the sealing gasket runs all around the perimeter of the interface where the two parts meet.

[0022] The invention offers, in particular, the following advantages: - Compared to a separate gasket, there is no risk of the overmolded gasket moving during assembly. - elimination of the step of mounting the seal onto the plate, - Removal of the gasket groove on the plate, which reduces the overall size, - Compared to a welded solution, there is no weld bead, which reduces bulk and simplifies the two plastic parts. - A bi-injected part requires only one tooling.

[0023] The invention also relates to an acoustic attenuation device configured to be mounted on an air intake of a motor vehicle, said device comprising: - at least one airflow duct intended to channel said airflow along a flow direction of said airflow in the airflow duct, - at least one acoustic attenuation device as above, said acoustic attenuation device comprising a cavity and a neck connecting said cavity to said airflow duct, the acoustic attenuation device being formed by two separate pieces which are assembled, one of the pieces forming at least a bottom of the cavity and the other piece forming the neck.

[0024] According to one aspect of the invention, the part forming the neck is interposed (being sandwiched) between the part forming at least the bottom of the cavity and a rim of the flow conduit.

[0025] According to one aspect of the invention, the two assembled parts form a plurality of cavities and a plurality of necks. Thus, the two assembled parts form a plurality of acoustic attenuation devices.

[0026] For example, the part forming the necks is a plate with a plurality of holes to form the plurality of necks.

[0027] For example, the other piece forms the plurality of cavities, and is for example a piece with boxes to form these cavities.

[0028] According to one aspect of the invention, the cavities of the acoustic attenuation devices can all be of the same volume, or alternatively of different volumes.

[0029] According to one aspect of the invention, the cavities of the acoustic attenuation devices can all be of the same depth, or alternatively of different depths.

[0030] According to one aspect of the invention, a sealing gasket is present between the part forming the neck and the rim of the flow conduit.

[0031] According to one aspect of the invention, the part forming the neck has on each of its faces a sealing gasket, in particular overmolded, one of the sealing gaskets being intended for sealing with the part forming at least the bottom of the cavity and the other sealing gasket being intended for sealing with the rim of the flow conduit.

[0032] For example, the part forming the neck is provided with one or more orifices to allow the material forming the seals to flow, during manufacturing, on both sides to form the seals.

[0033] According to one aspect of the invention, when the assembled parts form a plurality of cavities and necks, the sealing gasket runs around the perimeter of all the cavities.

[0034] According to one aspect of the invention, the two parts forming the acoustic attenuation device(s) are not directly assembled with each other.

[0035] According to one aspect of the invention, the two pieces forming the acoustic attenuation element(s) are assembled with the rim of the flow duct, for example by means of screws which pass through the three pieces placed against each other, with in particular the piece forming the neck(s) in an intercalated position.

[0036] According to one aspect of the invention, the rim of the flow conduit has studs to receive the screws.

[0037] It is this assembly that allows the three pieces to be held together.

[0038] The three parts could be assembled using snap-fit ​​tabs.

[0039] According to one aspect of the invention, at least one of the parts and the rim of the flow conduit has one or more alignment pins configured to allow alignment of the parts with each other, for example during pre-positioning during assembly operations.

[0040] According to one aspect of the invention, the part forming the cavity or cavities is configured to serve as a support for pivoting shutters of an air inlet, in particular an air inlet of an AGS-type front panel module for "Air Grille Shutter" in English, including rotation axes for shutters arranged in row(s) in one or more windows of this support.

[0041] The invention also relates to a method for manufacturing a sound attenuation device which comprises the following steps: - place the part forming the neck(s) on an edge of the flow duct, - place the piece forming the cavity(es) against the piece forming the neck(s), - fix these two pieces to the rim of the drainage duct.

[0042] In one aspect of the invention, the necks opening in the airflow duct are aligned with each other. In other words, the necks opening in the airflow duct are substantially parallel to each other.

[0043] The present invention also relates to a ventilation, heating and / or air conditioning system for a motor vehicle which includes an acoustic attenuation device as described above, the acoustic attenuation device being installed at an air outlet or inlet of the ventilation, heating and / or air conditioning system.

[0044] Other features and advantages of the present invention will become more apparent upon reading the following description, provided by way of illustration and not limitation, and the accompanying drawings in which:

[0045] [Fig.1] Fig.1 is a schematic, perspective representation of an acoustic attenuation device according to the invention, configured to be mounted on an air intake of a motor vehicle;

[0046] [Fig.2] The [Fig.2] is a schematic, cross-sectional representation of the acoustic attenuation device of the [Fig.1];

[0047] [Fig.3] The [Fig.3] is a schematic, perspective representation of the cavity-forming part of the acoustic attenuation device of the [Fig.1];

[0048] [Fig.4] The [Fig.4] is a schematic representation of the cavity-forming part and the neck-forming part of the acoustic attenuation device of the [Fig.1].

[0049] Fig. 1 represents an acoustic attenuation device 1 configured to be mounted on an air intake 100 of a motor vehicle.

[0050] Air intake 100 belongs to a front panel module 110 of type AGS for "Air Grille Shutter" in English.

[0051] This front face module 110 includes rotation bearings 112 for shutters 114 arranged in rows in two windows 115.

[0052] The acoustic attenuation device 1 includes an airflow duct 50 intended to channel said airflow along a flow direction Fl of said airflow in the airflow duct 50.

[0053] The duct 50 is delimited, at least partially, by a shell 51 connected to the front face 110, this duct 50 extending from the air inlet 100. The shell 51 is for example made of plastic.

[0054] The acoustic attenuation device 1 comprises a plurality of acoustic attenuation members 10, each acoustic attenuation member 10 comprising a cavity 11 and a neck 12 connecting said cavity 11 to said airflow conduit 50, as can be clearly seen in Figures 2 and 3.

[0055] Each acoustic attenuation element 10 is formed by two separate pieces which are assembled, one of the pieces 20 forming at least one bottom of each cavity 11 and the other piece 30 forming the necks 12.

[0056] The neck 12 extends along a main extension axis AP parallel to the direction Fl of the airflow in the airflow duct 50, as can be clearly seen in [Fig.2].

[0057] Part 20 forms the plurality of cavities 11 of acoustic attenuation organs 10, and is configured to serve as a support for the pivoting shutters 114.

[0058] Parts 20 and 30 are molded plastic parts, produced by injection molding. The plastic material is, for example, polypropylene.

[0059] The invention allows the manufacture of a closed cavity 11 (except for the neck 12) by two plastic pieces 20 and 30 which are assembled.

[0060] In the example described, each cavity 11 is formed entirely on the part 20, and the other of the parts 30, in the form of a plate, which forms the necks 12, is configured to close the cavities 11 by leaving the neck 12 opening into the cavity 11.

[0061] Thus the volume of each cavity 11 is formed by the part 20.

[0062] In the example described, each cavity 11 is a box roughly shaped like a rectangular prism (i.e., a parallelepiped). Of course, other shapes are possible, for example with trapezoidal or rounded sections.

[0063] The axial dimension (or length) of the neck 12 corresponds to the thickness of the plate-shaped part 30 which defines the necks 12. Here the neck 12 is formed by a hole in the plate 30.

[0064] In an alternative (not shown), the cavity 11 is formed entirely on one of the parts which includes the neck 12, and the other of the parts, in particular in the form of a plate, defines the bottom of the cavity 11.

[0065] In a further variant (not shown), the cavity 11 is formed partly on one of the pieces which includes the neck 12, and partly on the other of the pieces which defines the bottom of the cavity 11.

[0066] In the example described, the plate-shaped part 30 has a compressible sealing gasket 40 configured to ensure sealing at the interface of the junction of the two parts 20 and 30.

[0067] The sealing gasket 40 is mounted on the material of the corresponding part 30.

[0068] Thus the part with the sealing gasket 40 is of the bi-material type with one material to form the part 30, in particular in injection molded plastic, and one material to form the sealing gasket 40. The gasket 40 is for example of the elastomer type, for example of SEBS material.

[0069] The part 30 forming the necks 12 has grooves 41 and the sealing gasket 40 extends at least partially into these grooves 41, as illustrated in particular in [Fig.4],

[0070] The grooves 41 on the face 32 of the part 30 forming the neck 12 allow the material of the sealing gasket 40 to be channeled at the time of injection into the manufacturing mold.

[0071] The grooves 41 are derived from the molding of part 30.

[0072] The sealing gasket 40 runs all around the junction interface of the two parts 20 and 30.

[0073] In addition, the sealing gasket runs around the perimeter of all the cavities 11, forming sealing bands 44 around each cavity 11.

[0074] In the example described, the cavities 11 are arranged on one long side of the part 20 in a row, and on the two opposite short sides.

[0075] The part 30 forming the necks 12 is interposed (being sandwiched) between the part 20 forming the cavities 11 and a rim 52 of the flow conduit 50.

[0076] The cavities 11 of the acoustic attenuation devices 10 can all be of the same volume, or alternatively of different volumes, as is the case in the example described.

[0077] Similarly, the cavities 11 of the acoustic attenuation devices can all be of the same depth, or alternatively of different depths.

[0078] If necessary, the part 30 forming the necks 12 has on each of these faces, a sealing gasket 40, in particular overmolded, one of the sealing gaskets 40 being intended for sealing with the part 20 forming at least the bottom of the cavity 11 and the other sealing gasket being intended for sealing with the rim 52 of the flow conduit 50.

[0079] For example, the part forming the neck 12 is provided with one or more orifices (not shown) to allow the material forming the sealing joints to flow, during manufacturing, on both faces to form the sealing joints.

[0080] The two parts 20, 30 forming the acoustic attenuation elements 10 are not directly assembled with each other.

[0081] The two pieces 20, 30 forming the acoustic attenuation elements 10 are assembled with the rim 52 of the flow conduit 50, here using screws 59 which pass through the three pieces placed against each other, with in particular the piece 30 forming the necks 12 in an intercalated position.

[0082] The rim 52 of the flow conduit has studs 56 to receive the screws 59, as illustrated in [Fig.1].

[0083] The two pieces 20, 30 forming the acoustic attenuation organs 10 are provided with openwork ears 29, 39 for the passage of the screws 59.

[0084] It is this assembly that allows the three pieces to be held together.

[0085] Where applicable, at least one of the parts and the rim of the flow conduit has one or more alignment pins configured to allow alignment of the parts with each other, for example during pre-positioning during assembly operations.

[0086] The manufacture of a sound attenuation device 1 involves the following steps: - place part 30, forming the necks 12, onto the rim 52 of the flow conduit, - place part 20, which forms the cavities 11, against part 30, which forms the necks 12. - fix these two pieces 20, 30 with the rim 52 of the drainage conduit.

Claims

Demands

1. Acoustic attenuation element (10), in particular configured to be assembled in an acoustic attenuation device (1) mounted on an air intake (100) of a motor vehicle, the acoustic attenuation element (10) comprising a cavity (11) and a neck (12) communicating with the cavity (11), the acoustic attenuation element (10) being formed by two separate parts (20, 30) which are assembled, one of the parts (20) forming at least one bottom of the cavity (11) and the other part (30) forming the neck (12).

2. Component according to the preceding claim, wherein the two parts (20, 30) are molded parts, in particular made of plastic, in particular by injection molding of a plastic material, the plastic material being for example polypropylene.

3. A component according to any one of the preceding claims, wherein the cavity (11) is formed entirely on one of the parts (20), and the other of the parts (30), in particular in the form of a plate, which forms the neck (12) is configured to close the cavity (11) by leaving the neck (12) opening into the cavity (11).

4. A component according to any one of claims 1 and 2, wherein the cavity (11) is formed entirely on one of the parts which includes the neck (12), and the other of the parts, in particular in the form of a plate, defines the bottom of the cavity (11).

5. A component according to any one of the preceding claims, wherein at least one of the two parts comprises a sealing gasket (40), in particular compressible, configured to ensure sealing at the interface of joining the two parts.

6. Component according to the preceding claim, in which the sealing gasket (40) is overmolded onto the material of the corresponding part, the gasket being for example of elastomer type, for example of SEBS material.

7. A component according to the preceding claim, wherein the part forming the neck (12) has at least one groove (41) and the sealing gasket (40) extends at least partially into this groove (41).

8. A sound attenuation device (1) configured to be mounted on a motor vehicle air intake, said device comprising: - at least one airflow duct (50) for channeling said airflow along a direction flow (Fl) of said airflow in the airflow duct, - at least one acoustic attenuation element (10) according to any one of the preceding claims, said acoustic attenuation element comprising a cavity (11) and a neck (12) connecting said cavity (11) to said airflow duct, the acoustic attenuation element being formed by two separate parts (20, 30) which are assembled, one of the parts forming at least one bottom of the cavity (11) and the other part forming the neck (12).

9. Device according to the preceding claim, wherein the part forming the neck (12) is interposed between the part (20) forming at least one bottom of the cavity (11) and an edge of the flow duct, and are in particular assembled with the edge of the flow duct (50), for example by means of screws which pass through the three parts placed against each other.

10. Device according to claim 8 or 9, wherein the two assembled parts form a plurality of cavities (11) and a plurality of necks (12).

11. Device according to any one of claims 8 to 10, wherein the part forming the cavity or cavities (11) is configured to serve as a support for pivoting flaps (114) of an air inlet, in particular an air inlet of a front panel module (110), in particular with axes of rotation for flaps arranged in row(s) in one or more windows of this support.

12. A method for manufacturing a sound attenuation device according to any one of claims 8 to 11, comprising the steps: - place the part (20) forming the neck(s) (12) on a rim (52) of the flow conduit (50), - place the part (30) forming the cavity(es) (11) against the part forming the neck(s), - fix these two pieces (20, 30) with the rim (52) of the drainage conduit.

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