Motor vehicle seat upholstery element

Abstract

The invention relates to a motor vehicle seat upholstery element (1), said element comprising a block (2) having a receiving face (3) and a cavity (4) having an opening (5), a plate (6) fixed to the periphery of said opening and an inertial electrodynamic transducer (9) for vibrating said plate, said element further comprising a sealed acoustic insulation wall (17) arranged over the entire external surface of said block, said wall having a receiving portion (14) extending opposite said receiving face, the remainder of said wall forming a complementary portion (15) of said receiving portion, the material of said receiving portion being elastically compressible, its Shore hardness being less than 25 Shore A and its Young's modulus in compression being less than 5 MPa. Figure 2

Description

Title of the invention: Motor vehicle seat trim element

[0001] The invention relates to a motor vehicle seat upholstery element.

[0002] It is known to produce a trim element - such as a headrest, a backrest or part of a backrest - for a motor vehicle seat, said element comprising: • a padding block made of elastically compressible air-porous material, said block having a face for receiving an occupant of said seat, said block being provided with a cavity having an opening opening towards said receiving face, • a rigid plate fixed by its periphery, by means of a decoupling means, on the periphery of said opening so as to conceal it, said plate having an internal face facing said cavity, • an inertial electrodynamic transducer comprising a coil and a magnet fixed on a support, said support being mounted by means of a suspension means integrally with said coil, so that said plate begins to vibrate when said transducer is powered, said coil being fixed on said internal face.

[0003] For the record, transduction is the operation enabling one physical quantity to be transformed into another, by means of a transducer which transforms the energy received in a given form, for example electrical energy, into usable energy in a different form, for example acoustic.

[0004] In the context of the invention, it is a question of transforming an electrical signal into an acoustic signal by using as a radiation surface the rigid plate on which the transducer is fixed, for example in order to deliver a sound audible by an occupant of the seat (music, message, etc.) or even a sound signal in phase opposition with the sound signal corresponding to the noise in the passenger compartment when the vehicle is moving.

[0005] We recall here that a transducer differs from a loudspeaker in the following way: • a loudspeaker comprises a magnet fixedly mounted on a support and a flexible membrane secured to a coil, said membrane vibrating when said loudspeaker is powered, • a transducer comprises a coil fixedly mounted on a rigid plate and a magnet mounted by means of a suspension means on said coil, so that said plate vibrates when said transducer is powered.

[0006] Ultimately, a loudspeaker is a self-contained system generating sound independently of the environment in which it is mounted, whereas a transducer uses the support on which it is fixed, in this case a rigid plate, to generate the expected sound.

[0007] Furthermore, the use of a transducer is advantageous because it takes up less space and is lighter than a loudspeaker.

[0008] However, with the embodiment of the prior art described above, the problem arises of having a closed “acoustic loading cavity” - that is to say a cavity where the acoustic waves coming from the transducer are channeled by the opening of said cavity -, in order to allow optimization of the transmission of said acoustic waves.

[0009] Furthermore, it is imperative to preserve the comfort of an occupant of the seat opposite the receiving face of the block.

[0010] The aim of the invention is to propose an arrangement making it possible to meet these expectations.

[0011] To this end, the invention proposes a motor vehicle seat upholstery element, said element comprising: • a padding block made of elastically compressible air-porous material, said block having a face for receiving an occupant of said seat, said block being provided with a cavity having an opening opening towards said receiving face, • a rigid plate fixed by its periphery, by means of a decoupling means, on the periphery of said opening so as to conceal it, said plate having an internal face facing said cavity, • an inertial electrodynamic transducer comprising a coil and a magnet fixed to a support, said support being mounted by means of a suspension means integrally with said coil, so that said plate begins to vibrate when said transducer is powered, said coil being fixed to said internal face,

[0012] said element further having the following characteristics: • it further comprises a sealed acoustic insulation wall arranged over the entire external surface of said block, so as to channel the passage of acoustic waves from said transducer through said opening, said wall having a receiving part extending opposite said receiving face, the remainder of said wall forming a complementary part of said receiving part, • the material of said receiving part is elastically compressible, its shore hardness being less than 25 shore A and its Young's modulus in compression being less than 5 MPa.

[0013] It is specified here that when it is said that the sealed acoustic insulation wall is arranged over the entire external surface of the block, it should be understood that said wall does not extend over the opening of the cavity.

[0014] With the proposed arrangement, the presence of the sealed acoustic insulation wall arranged over the entire external surface of the block makes it possible to channel the passage of acoustic waves from said transducer through the opening, in other words to close the “acoustic loading cavity”.

[0015] Furthermore, the use of a material as defined above to produce the receiving part is conducive, due to the flexibility of said material, to optimizing the comfort of an occupant of the seat.

[0016] Other features and advantages of the invention will appear in the following description, given with reference to the attached figures, in which:

[0017] [Fig.l] is a schematic sectional view according to an embodiment of a seat back provided with two upholstery elements arranged laterally on either side,

[0018] [Fig.2] is a detail view of [Fig.l],

[0019] [Fig.3] is a schematic sectional view of a transducer according to one embodiment, said transducer being fixed on a plate.

[0020] With reference to the figures, a motor vehicle seat upholstery element 1 is described, said element comprising: • a block 2 of padding made of elastically compressible air-porous material, said block having a receiving face 3 for an occupant of said seat, said block being provided with a cavity 4 having an opening 5 opening towards said receiving face, • a rigid plate 6 fixed by its periphery, by means of a decoupling means 7 - for example in the form of a rubber or flexible foam seal -, on the periphery of said opening so as to conceal it, said plate having an internal face 8 facing said cavity, • an inertial electrodynamic transducer 9 comprising a coil 10 and a magnet 11 fixed to a support 12 - in particular made of molded plastic material -, said support being mounted by means of a suspension means 13 integrally with said coil, so that said plate begins to vibrate when said transducer is powered, said coil being fixed to said internal face,

[0021] said element further having the following characteristics: • it further comprises a sealed acoustic insulation wall 17 arranged over the entire external surface of said block - said wall being for example glued to said block or inserted between said block and a cover as described below - so as to channel the passage of acoustic waves from said transducer through said opening, said wall having a receiving part 14 extending opposite said receiving face, the rest of said wall forming a complementary part 15 of said receiving part, • the material of said receiving part is elastically compressible, its shore hardness being less than 25 shore A and its Young's modulus in compression being less than 5 MPa.

[0022] The measurement of the Shore A hardness is carried out in particular according to the ISO 7619-1 standard.

[0023] According to various embodiments, the material of the complementary part 15 is chosen from: • identical to that of the receiving part 14, • or partly identical to that of said receiving part and partly different - being for example based on thermoplastic elastomer - from that of said receiving part, • or different - for example being based on thermoplastic elastomer - from that of said receiving part.

[0024] According to one embodiment, the receiving part 14 has a thickness of between 1 and 20 mm, so as to ensure comfort adapted to an occupant of the seat.

[0025] According to one embodiment, the material of the receiving part 14 is a closed-cell foam.

[0026] According to one embodiment, the foam forming the material of the receiving part 14 has a density of between 100 and 1500 kg / m3.

[0027] According to an embodiment not shown, the padding block 2 provided with the waterproof wall 17 is covered at least in part by a covering cap - for example based on textile or leather provided with a soft foam underlayer -, said cap having, at least opposite the plate 6, a resistance to the passage of air of less than 200 Nsrn3, so as to allow the propagation of acoustic waves.

[0028] According to the embodiment shown, the plate 6 is covered with a layer of comfort foam 16 with a resistance to the passage of air of less than 200 Nsrn3, so as to allow the propagation of acoustic waves; such a layer of comfort foam 16 can in particular be inserted between the plate 6 and a cover as described above.

[0029] According to one embodiment, the padding block 2 is made of foam - in particular polyurethane - molded with a density of between 30 and 80 kg / m3.

Claims

Claims

1. Element (1) for upholstering a motor vehicle seat, said element comprising: • a block (2) of padding made of elastically compressible air-porous material, said block having a receiving face (3) for an occupant of said seat, said block being provided with a cavity (4) having an opening (5) opening towards said receiving face, • a rigid plate (6) fixed by its periphery, by means of a decoupling means (7), on the periphery of said opening so as to conceal it, said plate having an internal face (8) facing said cavity, • an inertial electrodynamic transducer (9) comprising a coil (10) and a magnet (11) fixed to a support (12), said support being mounted by means of a suspension means (13) integrally with said coil, so that said plate begins to vibrate when said transducer is powered, said coil being fixed to said internal face, said element being characterized in that: • it further comprises a sealed acoustic insulation wall (17) arranged over the entire external surface of said block, so as to channel the passage of acoustic waves from said transducer through said opening, said wall having a receiving part (14) extending opposite said receiving face, the remainder of said wall forming a complementary part (15) of said receiving part, • the material of said receiving part is elastically compressible, its shore hardness being less than 25 shore A and its Young's modulus in compression being less than 5 MPa.

2. Element (1) according to claim 1, characterized in that the material of the complementary part (15) is either: • identical to that of the receiving part (14), • or partly identical to that of said receiving party and partly different from that of said receiving party, • or different from that of said receiving party.

3. Element (1) according to one of the preceding claims, characterized in that the receiving part (14) has a thickness of between 1 and 20 mm.

4. Element (1) according to any one of the preceding claims, characterized in that the material of the receiving part (14) is a closed-cell foam.

5. Element (1) according to the preceding claim, characterized in that the foam forming the material of the receiving part (14) has a density of between 100 and 1500 kg / m3.

6. Element (1) according to any one of the preceding claims, characterized in that the padding block (2) provided with the sealed wall (17) is covered at least in part by a covering cap, said cap having, at least opposite the plate (6), a resistance to the passage of air of less than 200 Nsm 3, so as to allow the propagation of acoustic waves.

7. Element (1) according to any one of the preceding claims, characterized in that the plate (6) is covered with a layer of comfort foam (16) with resistance to the passage of air of less than 200 Nsm3, so as to allow the propagation of acoustic waves.

8. Element (1) according to any one of the preceding claims, characterized in that the padding block (2) is made of molded foam with a density of between 30 and 80 kg / m3.

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