Motor vehicle seat headrest

Abstract

The invention relates to a headrest (1) for a motor vehicle seat, said headrest comprising a rigid structure for mounting said headrest at the top of the back of said seat, said structure being provided with at least one sound transmission plate (6), said plate being provided with an electrodynamic transducer (7), and being associated with said structure by means of an acoustic decoupling means (8) made of elastically deformable material, so as to prevent transmission of vibrations from said plate to said structure. Figure 1a

Description

Title of the invention: Headrest for a motor vehicle seat

[0001] The invention relates to a headrest for a motor vehicle seat and an assembly for generating anti-noise in the passenger compartment of said vehicle.

[0002] It is known to produce a headrest for a motor vehicle seat, said headrest comprising a rigid structure for mounting said headrest at the top of the back of said seat.

[0003] It is also known that the headrest is provided with at least one loudspeaker intended to emit an audible signal near the head of an occupant of the seat.

[0004] The sound signal may in particular be of the “anti-noise” type, so as to emit a sound in phase opposition with the noise generated inside the passenger compartment.

[0005] However, a loudspeaker has the disadvantages of taking up a significant amount of space, which makes it difficult to accommodate in a small room such as a headrest, and of significantly increasing the weight of the headrest which is equipped with it.

[0006] The aim of the invention is to propose a headrest making it possible to overcome these drawbacks.

[0007] To this end, the invention proposes a headrest for a motor vehicle seat, said headrest comprising a rigid structure for mounting said headrest at the top of the back of said seat, said structure being provided with at least one sound transmission plate, said plate being: • equipped with an electrodynamic transducer, • associated with said structure by means of an acoustic decoupling means made of elastically deformable material, so as to avoid transmission of vibrations from said plate to said structure.

[0008] In this description, the terms of positioning in space (lateral, transverse, high, rear, etc.) are taken with reference to the headrest arranged in the vehicle in use.

[0009] 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.

[0010] 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 plate on which the transducer is fixed.

[0011] With the proposed arrangement, the loudspeaker is replaced by a transducer which, as is known, takes up less space and is lighter.

[0012] According to another aspect, the invention provides an anti-noise generation assembly in the passenger compartment of said vehicle.

[0013] Other features and advantages of the invention will appear in the following description, given with reference to the attached figures in which:

[0014] [Fig.1a] and

[0015] [Fig.lb] are schematic exploded perspective views ([Fig. la]) and non-exploded ([Fig.lb]) of a headrest according to a first embodiment,

[0016] [Fig.2a] and

[0017] [Fig.2b]] are schematic views in exploded perspective ([Fig.2a]) and non-exploded ( [Fig.2b]) of a headrest according to a second embodiment,

[0018] [Fig.3a],

[0019] [Fig.3b],

[0020] [Fig.3c] and

[0021] [Fig.3d] are schematic views in partial section of a headrest according to four variants of a third embodiment.

[0022] With reference to the figures, a headrest 1 for a motor vehicle seat is described, said headrest comprising a rigid structure for mounting said headrest at the top of the back of said seat, said structure being provided with at least one sound transmission plate 6, said plate being: • equipped with an electrodynamic transducer 7, • associated with said structure by means of an acoustic decoupling means 8 made of elastically deformable material - in particular made of elastomeric material, in particular molded -, so as to avoid transmission of vibrations from said plate to said structure.

[0023] According to the embodiments shown, the structure is provided with two plates 6 arranged laterally on either side, so as to arrange a transducer 7 on each side of the head of an occupant of the seat.

[0024] The first and second embodiments relating respectively to Figures 1 and 2 are now described.

[0025] According to the embodiments shown in figures 1 and 2, the structure comprises: • a frame 2 comprising two parallel metal rods 3, • a part 4 - in particular made of molded plastic material - for receiving a cushion 5 and absorbing energy in the event of an impact to the head of an occupant, said rods each being fitted into a respective housing 16 provided in said part - here in the rear part -, said part having a general profile shape defining in lateral view an inverted U-shaped section, so as to define a cavity 18, at least one transducer 7 being housed in said cavity.

[0026] According to the embodiments shown, the part 4 is provided with a network of ribs 12, in order to strengthen its bending rigidity.

[0027] According to the embodiments shown, the ribs 12 are arranged in cross-hatches.

[0028] According to one embodiment, the cushion 5 is in the form of a block of foam with molded skin, the skin of said foam being arranged on the outside, said foam having a hardness greater than 25 shore A.

[0029] In particular, the foam may have a hardness of the order of 30 shore A.

[0030] According to one embodiment, the foam of the block has a density of between 0.20 and 0.30, and in particular of the order of 0.25.

[0031] According to the embodiments shown, the cavity 18 opens outwards, so as to form a “bass-reflex” system (adjustable by the size of the vent which is provided to allow said cavity to open outwards) when the plate 6 is vibrated by the transducer 7 associated with it.

[0032] According to the first embodiment shown in figures 1a and 1b, the decoupling means 8 is a single piece - being in particular produced by molding - and extends transversely on either side in the cavity 18, two plates 6 each provided with a transducer 7 being respectively fixed at the lateral ends of said means.

[0033] According to this embodiment, the plates 6 laterally conceal the cavity 18.

[0034] According to an embodiment not shown, the plates 6 can be inclined so as to orient the transducers 7 towards the ears of an occupant of the seat.

[0035] According to the second embodiment shown in figures 2a and 2b, each of the rods 3 receives a respective decoupling means 8 - in particular molded - arranged in the cavity 18, each of the decoupling means 8 receiving a plate 6 provided with a transducer 7.

[0036] According to this embodiment, the plates 6 are arranged in front of the decoupling means 8, the part 4 being perforated opposite said plates so as to allow the propagation of sound towards the occupant of the seat.

[0037] In a variant not shown, the plates 6 can be arranged laterally on the decoupling means 8.

[0038] The third embodiment relating to Figures 3a to 3d will now be described.

[0039] According to the variants of this third embodiment, the structure is formed by a metal frame 2, at least one plate 6 provided with a transducer 7 being associated with said frame by means of a decoupling means 8.

[0040] According to this third embodiment: • the headrest is provided with a padding block 10 made of elastically compressible foam, • said block is provided with at least one cavity 11, • said cavity has an opening 22 closed by a plate 6 fixed by its periphery 13 - in particular by gluing - on the periphery of said opening, • the decoupling means 8 is formed by the foam of said block interposed between the frame 2 and said plate.

[0041] In a manner not shown, the cavity 11 can be perforated so as to form a “bass-reflex” system as mentioned above.

[0042] According to the variants shown in figures 3a, 3b and 3d, the plate 6 is covered, opposite the cavity 11, by a layer of foam 23 integrated into the general volume of the block 10, said layer being: • either from molding said block, as shown in figures 3a and 3d, • or formed, as shown in [Fig.3b], by a foam block having a porosity greater than 0.95 and a resistivity to the passage of air less than 5000 Nsnr4, so as to improve the passage of acoustic waves.

[0043] According to the variant shown in [Fig.3c], the plate 6 is not covered by a layer of foam integrated into the general volume of the block 10.

[0044] According to the variant shown in [Fig.3d], the plate 6 is arranged between the cavity 11 and an annex cavity 20, said plate being fixed by its periphery 13 on a lip 21 resulting from molding of the block 10, said lip surrounding said plate, so as to allow an accentuated decoupling between said plate and the frame 2.

[0045] In a manner not shown, it is possible to provide, in all the variants of the third embodiment, to have between the periphery 13 of the plate 6 and the periphery of the opening 22 an ultra-compressible seal (of compressibility greater than that of the foam of the block 10) allowing improved decoupling for very low frequencies, in particular below 100 Hz.

[0046] Finally, a noise reduction generation assembly is described in a motor vehicle passenger compartment, said assembly comprising a headrest 1 as described previously and a noise reduction production system connected to at least one transducer 7.

[0047] According to a variant, the transducer 7 can be used to generate a conventional noise, such as music, instead of an anti-noise.

Claims

Claims

1. Headrest (1) for a motor vehicle seat, said headrest comprising a rigid structure for mounting said headrest at the top of the back of said seat, said headrest being characterized in that said structure is provided with at least one sound transmission plate (6), said plate being: • provided with an electrodynamic transducer (7), • associated with said structure by means of an acoustic decoupling means (8) made of elastically deformable material, so as to prevent transmission of vibrations from said plate to said structure.

2. Headrest according to claim 1, characterized in that the structure is provided with two plates (6) arranged laterally on either side, so as to arrange a transducer (7) on each side of the head of an occupant of the seat.

3. Headrest according to one of claims 1 or 2, characterized in that the structure comprises: • a frame (2) comprising two parallel metal rods (3), • a part (4) for receiving a cushion (5) and absorbing energy in the event of an impact to the head of an occupant, said rods each being fitted into a respective housing (16) provided in said part, said part having a general profile shape defining in lateral view an inverted U-shaped section, so as to define a cavity (18), at least one transducer (7) being housed in said cavity.

4. Headrest according to claims 2 and 3, characterized in that the decoupling means (8) is in one piece and extends transversely on either side in the cavity (18), two plates (6) each provided with a transducer (7) being respectively fixed at the lateral ends of said means.

5. Headrest according to claims 2 and 3, characterized in that each of the rods (3) receives a respective decoupling means (8) arranged in the cavity (18), each of the decoupling means (8) receiving a plate (6) provided with a transducer (7).

6. Headrest according to one of claims 1 or 2, characterized in that the structure is formed by a metal frame (2), at least one plate (6) provided with a transducer (7) being associated with said frame by means of a decoupling means (8).

7. Headrest according to the preceding claim, characterized in that: • it is provided with a padding block (10) made of elastically compressible foam, • said block is provided with at least one cavity (11), • said cavity has an opening (22) closed by a plate (6) fixed by its periphery (13) at the periphery of said opening, • the decoupling means (8) is formed by the foam of said block interposed between the frame (2) and said plate.

8. Headrest according to the preceding claim, characterized in that the plate (6) is covered, opposite the cavity (11), by a layer of foam (23) integrated into the general volume of the block (10), said layer being: • either produced by molding said block, • or formed by a block of foam having a porosity greater than 0.95 and a resistivity to the passage of air less than 5000 Nsnr4, so as to improve the passage of acoustic waves.

9. An assembly for generating anti-noise in a motor vehicle passenger compartment, said assembly comprising a headrest (1) according to any one of the preceding claims and an anti-noise production system connected to at least one transducer (7).

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