LOUDSPEAKER FOR A MOTOR VEHICLE AND MOTOR VEHICLE COMPRISING SUCH A LOUDSPEAKER

Abstract

The invention relates to a loudspeaker (3) for a motor vehicle, said loudspeaker (3) being configured to be fixed to a sheet metal (5) of the vehicle opposite an opening (5a) provided in said sheet metal (5), said loudspeaker (3) comprising at least:– an electroacoustic transduction system (7);– a first membrane (9), called an active membrane, connected to said transduction system (7);– a second membrane (13), called a protective membrane, arranged at a distance from the first membrane (9), and configured to protect the first membrane (9);characterized in that said loudspeaker (3) comprises an acoustic absorbing material (17) arranged around said membranes (9; 13) and opposite the space separating said first (9) and second (13) membranes. Abstract figure: [Fig. 1]

Description

Title of the invention: LOUDSPEAKER FOR A MOTOR VEHICLE AND MOTOR VEHICLE COMPRISING A SUCH SPEAKER

[0001] The present invention relates generally to the field of audio systems for motor vehicles which comprise one or more loudspeakers. The present invention relates more particularly to the loudspeakers of such an audio system mounted on a bodywork element of a motor vehicle.

[0002] Indeed, contemporary motor vehicles are generally equipped with audio systems. Such audio systems on board a motor vehicle thus comprise several sets of loudspeakers, one of the sets being generally arranged towards the left lateral side of the vehicle and the other set towards the right lateral side thereof, this in order to provide the best possible listening area for the passengers of the vehicle by placing them substantially between the two sets of loudspeakers.

[0003] These two sets of speakers must have a reduced size to be embedded, if necessary, in one of the doors of the vehicle or any other bodywork element, for example in a trim panel. These speakers can thus be placed at the front and rear right and left of the vehicle, for example on the rear console or on the dashboard area.

[0004] These speaker sets include speakers emitting in different frequency bands. For example: - “mid-high” type loudspeakers with, in some cases, but not necessarily, a high-pass filter ensuring the attenuation of low frequency signals; - “bass” type loudspeakers, i.e. emitting in the low frequency range which forms the bass, these loudspeakers are generally formed by an acoustic enclosure, the loudspeaker-acoustic enclosure assembly being generally designated by the term “subwoofer”

[0005] This bass speaker is generally bulky and needs to be mounted in an enclosure, called an acoustic enclosure, ideally closed in order to isolate the air zones at the front and rear of the speaker. The sizing of this enclosure in fact conditions the quality of the sound produced in the low frequencies by the speaker and an infinite volume would theoretically be desirable in order to give the bass speaker a load volume large enough to allow it to reproduce the low frequencies. Usually, the volume of this enclosure, and by extension of the bass speaker, is at least 15 liters. It should be noted, however, that the volume of the speaker can be reduced at the cost of a reduction in the sensitivity of said speaker, but this results in an increase in the power required to produce the same effect (for example at the same sound intensity) as in the absence of volume reduction.

[0006] Such a volume is difficult to find in a vehicle. Such a bass speaker takes up either the space of a storage volume in the car or, most often, a part of the trunk volume.

[0007] Thus, a bass speaker is advantageously mounted on a bodywork element, for example a bodywork sheet delimiting the passenger compartment of the vehicle. More particularly, the speaker is fixed on the sheet, opposite an opening made therein, and for example in the passenger compartment, the sound waves emitted by the speaker then being able to propagate into the passenger compartment through the opening made in said bodywork sheet.

[0008] However, such an arrangement of a bass speaker on a body sheet has disadvantages. For example, there is the risk that sound waves (or noises) coming from outside will penetrate into the passenger compartment and degrade the acoustic comfort of the users of the motor vehicle. This concept is also referred to as "acoustic insulation" and must therefore be as good as possible.

[0009] Furthermore, such an arrangement must also be watertight at the junction between the sheet metal and the loudspeaker, in fact it is imperative that water cannot infiltrate into the loudspeaker to avoid damaging it and / or it becoming non-functional. The watertightness of this arrangement must also prevent water or moisture from entering the passenger compartment through the opening made in said sheet metal.

[0010] The present invention thus proposes to remedy at least one of the aforementioned drawbacks by proposing a new type of loudspeaker for a motor vehicle, said loudspeaker being configured to be fixed to a sheet metal of the vehicle, for example a bodywork sheet metal, opposite an opening made in said sheet metal, said loudspeaker comprising at least: - an electroacoustic transduction system; - a first membrane, called the active membrane, connected to said transduction system; - a second membrane, called a protective membrane, arranged at a distance from the first membrane, and configured to protect the first membrane; characterized in that said loudspeaker comprises an acoustic absorbing material arranged around said membranes and opposite the space separating said first and second membranes.

[0011] The presence of an acoustic absorbing material arranged opposite the space separating said first and second membranes makes it possible in particular to dampen the acoustic resonances generated in this intermembrane space (this amplifies the transmission of sound waves). The acoustic absorbing material makes it possible, among other things, to dampen these resonances and to limit, or even prevent, sound waves coming from the outside from being transmitted to the interior of the vehicle via said loudspeaker (and the associated opening made in the sheet metal).

[0012] According to a possible characteristic, said loudspeaker comprises a chassis to which the first and second membranes are fixed by means of suspensions, said acoustic absorbing material being located outside and at the periphery of said suspensions.

[0013] According to another possible characteristic, said loudspeaker comprises a housing in which at least the first and second membranes are arranged, said acoustic absorbing material being arranged in said housing. The acoustic material is advantageously placed in said housing, in order to protect it from environmental conditions (in particular from attacks), and to prevent the acoustic absorbing material from degrading and losing its acoustic absorbing properties.

[0014] According to another possible characteristic, said loudspeaker comprises a sealing gasket configured, when said loudspeaker is in the mounted position on said sheet metal, to be arranged between said housing and the bodywork sheet metal. Thus, the seal is configured so that the loudspeaker is sealed at the level of the housing in which elements of said loudspeaker are arranged. In addition, the seal is advantageously arranged, at least partially, in said housing, in order to protect it from environmental conditions.

[0015] According to another possible characteristic, said seal and said sound-absorbing material are configured so that in the mounted position of the loudspeaker on said sheet metal, the sound-absorbing material is arranged between the housing and the seal, while the seal is arranged between said sound-absorbing material and the bodywork sheet metal. The gasket and the sound-absorbing material are thus advantageously arranged one on top of the other (or superimposed) and resting respectively on said sheet metal and on the housing, in order to minimize the volume occupied by these elements. This arrangement also makes it possible to stiffen the resulting assembly, and thus promotes the proper functioning of said loudspeaker.

[0016] According to another possible characteristic, said acoustic absorbing material has a material thickness, in a radial or transverse direction (for example relative to the axis of revolution of the membranes), of at least 10 mm, and preferably between 20 mm and 40 mm.

[0017] According to another possible characteristic, said sound-absorbing material is a open-porous material, such as polyurethane foam, textile or plastic felts, mineral fibers, etc.

[0018] According to another possible characteristic, said loudspeaker is configured to emit acoustic waves having a frequency of less than 250 Hz, and advantageously frequencies between 20 and 200 Hz. The loudspeaker according to the invention is thus advantageously a loudspeaker of the “woofer” or “subwoofer” type.

[0019] According to another possible characteristic, said acoustic absorbing material has a resistivity to the passage of air greater than 10 kPa.s.m2 (or rayl / cm), and advantageously a resistivity to the passage of air of between 20 and 50 kPa.s.m2.

[0020] The present invention also relates to an arrangement for a motor vehicle, characterized in that said arrangement comprises: - a sheet of the vehicle, for example the bodywork, in which an opening is made; - a loudspeaker as defined above which is fixed to the sheet metal and opposite said opening in the sheet metal.

[0021] According to a possible characteristic, said sheet metal comprises at least two stiffening structures, at least one part of the loudspeaker (for example a part of the housing and / or the sealing gasket) being positioned between said at least two stiffening structures of the sheet metal.

[0022] The invention also relates to a motor vehicle, for example thermal, electric or hybrid, characterized in that it comprises an arrangement for a motor vehicle as defined above.

[0023] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of a particular embodiment of the invention, given solely for illustrative and non-limiting purposes, with reference to the appended drawings, in which: - [Fig.l] illustrates a very schematic, sectional view of an arrangement according to the invention comprising a loudspeaker fixed to a body sheet.

[0024] In the following description, the term "comprise" is synonymous with "include" and is not limiting in that it allows the presence of other elements in the vehicle, or the structure to which it relates. It is understood that the term "comprise" includes the terms "consist of".

[0025] In the present application, it will be noted that "substantially parallel" means a direction deviating by at most 20°, or even by at most 10° or by at most 5° from a parallel direction. It will also be noted that "substantially orthogonal" means a direction deviating by at most 20°, or even by at most 10° or by at most 5° from an angle of a value of 90°.

[0026] [Fig.l] thus illustrates a very schematic, partial and sectional view of an arrangement 1 comprising a loudspeaker 3 and a sheet metal 5 of the motor vehicle, for example of the bodywork, on which said loudspeaker 3 is mounted (or fixed). Said sheet metal 5 comprises in particular at least one opening 5a opening into the passenger compartment of said vehicle (not shown), said loudspeaker 3 being arranged opposite said opening 5a so that the sound waves generated by the loudspeaker 3 can pass through said opening 5a to enter the passenger compartment of the vehicle.

[0027] Said loudspeaker 3 is advantageously configured to emit acoustic waves having a frequency of less than 250 Hz, and advantageously frequencies of between 20 and 200 Hz. The loudspeaker 3 according to the invention is for example a loudspeaker of the “woofer” or “subwoofer” type.

[0028] Thus, the loudspeaker 3 is a device intended to produce sounds from an electrical signal, and this comprises in particular: - an electroacoustic transduction system 7 configured to transform an electrical signal into an acoustic wave; - a first membrane 9, called the active membrane, connected to the transduction system 7 so as to move with and / or under the effect of said system 7, in order to move and “make the air vibrate” to generate acoustic waves; - a frame 10 (also referred to as a “salad bowl”), advantageously of substantially truncated cone shape, allowing, among other things, by means of a suspension 11, the active membrane 7 to be connected and fixed to said frame 10; - a second membrane 13, called the protective membrane, arranged opposite the active membrane 9 and fixed to said frame 9 by means of another suspension 11; - a housing 15, for example made of plastic, in which are arranged at least the transduction system 7, the chassis 9 and said first and second membranes 9 and 13.

[0029] It will be noted that by electroacoustic transduction system 7 is meant a set of elements, such as a magnet, a moving coil, a core, field plates, etc. configured to transform an electrical signal into a mechanical signal (or even into changes in air pressure).

[0030] The first and second membranes 9 and 13 are generally arranged coaxially with respect to each other. In addition, said membranes 9 and 13 are arranged at a distance from each other, thus forming a space called “intermembrane space” delimited and closed axially by each of the membranes 9 and 13. It will be noted that the axis of revolution of said membranes 9 and 13 is advantageously orthogonal to the main extension plane of the opening 5a.

[0031] Said second membrane 13 is configured to protect the first membrane 9 from projections or any other element coming from the passenger compartment and which may pass through the opening 5a made in the sheet 5, this in order to avoid any damage to the first membrane 9.

[0032] Furthermore, said loudspeaker 3 comprises an acoustic absorbing material 17 arranged around said first and second membranes 9 and 13, opposite the intermembrane space. Said acoustic absorbing material 17 therefore closes the radial (and annular) periphery of the intermembrane space defined by the membranes 9 and 13.

[0033] The sound-absorbing material 17 has, for example, an annular shape and surrounds (or encircles) the space between the membranes 9 and 13 (and therefore said membranes), the sound-absorbing material advantageously extending at least over the entire distance separating said membranes 9 and 13 (therefore at least respectively from the suspensions 11 of the first membrane 9 to the suspensions 11 of the second membrane 13). In addition, said sound-absorbing material 17 is therefore advantageously located outside said intermembrane space and at the periphery of said suspensions 11.

[0034] Said loudspeaker 3 further comprises a sealing gasket 19 configured to provide sealing between the housing 15 and the sheet metal 5 on which the loudspeaker 3 is fixed.

[0035] Thus, the sound-absorbing material 17 and the seal 19 are advantageously arranged in the housing 15, and for example one in contact with the other, that is to say that when the loudspeaker 3 is in the mounted position (therefore fixed on the sheet metal 5), the sound-absorbing material 17 is located between the housing 15 (in particular a wall of the housing) and the seal 19, while the seal 19 is located between said sound-absorbing material 17 and the bodywork sheet metal 5.

[0036] The sound-absorbing material 17 is therefore interposed between a wall of the housing 15 and the seal 19, each of the ends of the sound-absorbing material 17 thus bears respectively on the housing 15 and the seal 19.

[0037] Furthermore, said sound-absorbing material 17 is a material with open porosity, such as polyurethane foam, textile or plastic felts, mineral fibers, etc. Said sound-absorbing material 17 has, for example, a resistivity to the passage of air greater than 10 kPa.s.m2 (or rayl / cm), and advantageously a resistivity to the passage of air of between 20 and 50 kPa.s.m2.

[0038] The sound-absorbing material 17 has substantially the shape of a ring or a torus which surrounds the intermembrane space. Furthermore, said sound-absorbing material 17 has a material thickness, in a radial direction (i.e. along an axis substantially parallel to the main extension planes of said membranes, or along an axis orthogonal to the axis of revolution of the membranes) of the housing 15 or according to the thickness of the ring, of at least 10 mm, and preferably between 20 mm and 40 mm.

[0039] Furthermore, the bodywork sheet 5 in which the opening 5a is arranged comprises at least two stiffening structures 5b. Said stiffening structures 5b are for example ribs, bosses, stampings, etc. which are configured to define a receiving housing for the seal 19 and the housing 15 of the loudspeaker 3, in particular when said loudspeaker 3 is fixed to said sheet 5, for example by means of screws. Advantageously, the receiving housing of the seal 19 is therefore a flat (and rigid) surface, arranged in the sheet 5, framed by said stiffening structures 5b.

[0040] Said structures 5b are therefore arranged concentrically with respect to one another, and can be continuous or intermittent, as long as the sheet 5 is sufficiently rigid to guarantee the contact of said seal 19 against the sheet 5 (and thus guarantee the sealing of said assembly).

[0041] In alternative embodiments not shown, the bodywork sheet 5 in which the opening 5a is arranged comprises a single stiffening structure 5b, for example a boss, a stamping, a rib, etc., said seal 19 bearing on the stiffening structure 5b, or on the sheet 5 in the immediate vicinity, or even in contact, with said structure 5b.

[0042] In another variant embodiment, said seal 19 is arranged concentrically around the absorbent acoustic material 17. Said seal 19 is then interposed between the absorbent material 17 and the wall of the housing 15, and is for example in contact with said material 17 and the wall of the housing 15.

Claims

Claims

1. Loudspeaker (3) for a motor vehicle, said loudspeaker (3) being configured to be fixed on a sheet metal (5) of the vehicle, opposite an opening (5a) arranged in said sheet metal (5), said loudspeaker (3) comprising at least: - an electroacoustic transduction system (7); - a first membrane (9), called active membrane, connected to said transduction system (7); - a second membrane (13), called protective membrane, arranged at a distance from the first membrane (9), and configured to protect the first membrane (9); characterized in that said loudspeaker (3) comprises an acoustic absorbing material (17) arranged around said membranes (9; 13) and opposite the space separating said first (9) and second (13) membranes.

2. Loudspeaker (3) according to the preceding claim, characterized in that said loudspeaker (3) comprises a housing (15) in which at least the first and second membranes (9, 13) are arranged, said acoustic absorbing material (17) being arranged in said housing (15).

3. Loudspeaker (3) according to the preceding claim, characterized in that said loudspeaker (3) comprises a sealing gasket (19) configured, when said loudspeaker (3) is in the mounted position on said sheet metal (5), to be arranged between said housing (15) and the bodywork sheet metal (5).

4. Loudspeaker (3) according to the preceding claim, characterized in that said seal (19) and said sound-absorbing material (17) are configured so that in the mounted position of the loudspeaker (3) on said sheet metal (5), the sound-absorbing material (17) is arranged between the housing (15) and the seal (19), while the seal (19) is arranged between said sound-absorbing material (17) and the body sheet metal (5).

5. Loudspeaker (3) according to any one of the preceding claims, characterized in that said acoustic absorbing material (17) has a thickness, in a radial direction, of at least 10 mm.

6. Loudspeaker (3) according to any one of the preceding claims, characterized in that said acoustic absorbing material (17) is an open porosity material.

7. Loudspeaker (3) according to any one of the preceding claims, characterized in that said sound-absorbing material (17) has an air flow resistivity greater than 10 kPa.s.m2.

8. Arrangement (1) for a motor vehicle, characterized in that said arrangement (1) comprises: - a sheet metal (5) of the vehicle in which an opening (5a) is arranged - a loudspeaker (3) according to any one of the preceding claims which is fixed to the sheet metal (5) and opposite said opening (5a) of the sheet metal (5).

9. Arrangement (1) according to the preceding claim, characterized in that said sheet metal (5) comprises at least two stiffening structures (5b), at least a part of the loudspeaker (3) being positioned between said at least two stiffening structures (5b) of the sheet metal (5).

10. Motor vehicle, characterized in that it comprises an arrangement according to claim 8 or 9.

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