Headrest for a car seat

Abstract

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

Description

Detailed Description of the Invention

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

[0002] It is known to manufacture a headrest for a seat of a motor vehicle, said headrest comprising a rigid structure for mounting said headrest on top of the backrest of the seat.

[0003] It is also known that head restraints are fitted with at least one loudspeaker designed to emit a sound signal in the vicinity of the head of a seat occupant.

[0004] In particular, the sound signal may be of the "anti-noise" type, so as to emit a sound in anti-phase with respect to the noise generated within the passenger compartment.

[0005] However, a drawback of loudspeakers is that they take up a lot of space, are difficult to fit into small components such as headrests, and the headrests they are fitted into can be quite heavy.

[0006] The object of the present invention is to provide a headrest which overcomes these drawbacks.

[0007] To this end, the invention relates to a headrest for a seat of a motor vehicle, comprising: the headrest comprises a rigid structure for mounting the headrest to an upper portion of the seat back; The structure is provided with at least one acoustically transmitting plate, The plate is An electrodynamic transducer is provided; It is proposed that the headrest is connected to the structure via acoustic decoupling means made of an elastically deformable material so as to prevent the transmission of vibrations from the plate to the structure.

[0008] In this specification, terms referring to positioning in space (lateral, lateral, upper, rearward, ...) refer to the head restraint positioned within the vehicle in the situation of use.

[0009] By the way, transduction is the operation of converting one physical quantity into another by a transducer that converts energy received in a given form, such as electrical energy, into energy that can be used in another form, such as acoustic energy.

[0010] The present invention involves converting an electrical signal into an acoustic signal using a rigid plate with a transducer attached as the radiating surface.

[0011] Incidentally, transducers differ from loudspeakers in the following ways: The loudspeaker comprises a magnet fixedly attached to a support and a flexible diaphragm attached to a coil, the diaphragm vibrating when power is supplied to the loudspeaker; The transducer comprises a coil fixedly attached to a rigid plate and a magnet attached to the coil via a suspension means such that the plate vibrates when power is supplied to the transducer.

[0012] Ultimately, a loudspeaker is an autonomous system that produces sound independent of the environment in which it is mounted, whereas a transducer produces the expected sound using the support to which it is mounted, in this case a rigid plate.

[0013] In the proposed arrangement, loudspeakers are replaced by transducers, which, as is well known, take up less space and are lighter in weight.

[0014] According to another aspect, the invention proposes an assembly for generating anti-noise in the passenger compartment of said vehicle.

[0015] Further features and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings.

[0016] 1a and 1b are a schematic exploded perspective view (FIG. 1a) and a schematic non-exploded perspective view (FIG. 1b) of a headrest according to a first embodiment.

[0017] 2a and 2b are schematic exploded perspective view (FIG. 2a) and non-exploded perspective view (FIG. 2b) of a headrest according to a second embodiment.

[0018] 3a, 3b, 3c and 3d are schematic partial cross-sectional views of headrests according to four variations of the third embodiment.

[0019] With reference to the figures, a headrest 1 for a vehicle seat is described.

[0020] the headrest comprises a rigid structure for mounting the headrest to an upper portion of the seat back; The structure is provided with at least one acoustic transmission plate 6, The plate is an electrodynamic transducer 7 is provided which is fixed, for example by gluing, by welding or by fitting into receiving means provided on said plate for this purpose, The plate is connected to the structure via acoustic decoupling means 8 made of an elastically deformable material, in particular a molded elastomeric material, for example ethylene propylene diene monomer (EPDM), or a foam, in particular polyurethane, so as to prevent the transmission of vibrations from the plate to the structure.

[0021] In one embodiment, the plate 6 has a thickness of 3 to 8 mm.

[0022] In one embodiment, the plate 6 has a resistance of 100 to 500 kg / m 3 has a density of

[0023] Such thickness and / or density characteristics result in a plate 6 with a low mass that can be easily vibrated by a connected transducer.

[0024] In one embodiment, the plate 6 has a Young's modulus greater than 100 MPa.

[0025] In one embodiment, the decoupling means 8 has a Young's modulus of less than 20 kPa.

[0026] In one embodiment, the decoupling means 8 has a loss factor greater than 0.2.

[0027] According to the embodiment shown, the structure is provided with two plates 6 arranged laterally on either side so as to place a transducer 7 on each side of the seat occupant's head.

[0028] Next, a first embodiment and a second embodiment shown in FIG. 1 and FIG. 2, respectively, will be described.

[0029] According to the embodiment shown in Figures 1 and 2, the structure comprises: a frame 2 comprising two parallel metal rods 3; a part 4 made of a specially moulded plastic material for receiving the cushion 5 and absorbing energy in the event of an impact of the occupant's head, The rods are each telescopically housed in a respective housing 16 provided in the part, here at the rear, said part has a lateral profile generally defining an inverted U-shaped cross section in side view so as to define a cavity 18; At least one transducer 7 is housed within said cavity.

[0030] According to the embodiment shown, the part 4 is provided with a network of ribs 12 to reinforce its bending stiffness.

[0031] In the embodiment shown, the ribs 12 are arranged in a grid.

[0032] According to one embodiment, the cushion 5 is in the form of a block of foam with a molded skin, said foam skin being disposed on the outside, said foam having a Shore A hardness of greater than 25.

[0033] In particular, the foam may have a Shore A hardness of the order of 30.

[0034] In one embodiment, the foam of the block has a density of 0.20 to 0.30, in particular of the order of 0.25.

[0035] According to the embodiment shown, the cavity 18 opens outwards when vibrated by the transducer 7 to which the plate 6 is connected, forming a "bass reflex" system (adjustable by the size of the vent provided to allow the cavity to open outwards).

[0036] According to a first embodiment, shown in FIGS. 1a and 1b, said decoupling means 8 are integral, in particular obtained by moulding, and extend transversely on both sides of said cavity 18, Two plates 6, each equipped with a transducer 7, are fixed to the lateral ends of said means.

[0037] According to this embodiment, the plate 6 laterally conceals a cavity 18 .

[0038] In an embodiment not shown, the plate 6 can be tilted to point the transducer 7 towards the ears of the seat occupant.

[0039] According to a second embodiment, shown in figures 2a and 2b, said rods 3 each receive a respective decoupling means 8 arranged in said cavity 18, which is particularly shaped, Said decoupling means 8 each receive a plate 6 on which a transducer 7 is mounted.

[0040] According to this embodiment, the plate 6 is arranged in front of the decoupling means 8, the perforated part 4 facing said plate so as to allow sound propagation in the direction of the seat occupant.

[0041] In a variant not shown, the plate 6 can be arranged laterally on the decoupling means 8 .

[0042] Next, a third embodiment will be described, as shown in Figures 3a to 3d.

[0043] According to this variant of the third embodiment, the structure is formed by a metal frame 2, At least one plate 6 on which a transducer 7 is mounted is connected to said frame via decoupling means 8 .

[0044] According to this third embodiment, the headrest is provided with a padding block 10 made of elastically compressible foam, The block is provided with at least one cavity 11, said cavity has an opening 22 which is closed at its periphery by a plate 6 which is fixed, in particular by gluing, by said periphery 13; The decoupling means 8 are formed by the foam of the block interposed between the frame 2 and the plate.

[0045] Although not shown, the cavity 11 can be drilled to form a "bass reflex" system as described above.

[0046] According to the variant shown in figures 3a, 3b and 3d, the plate 6 is covered, facing the cavity 11, by a layer of foam 23 which merges into the entire volume of the block 10; The layer comprises: As shown in Figures 3a and 3d, the block is molded or molded with a porosity of more than 0.95 and a resistance of 5000 N·s·m to improve the passage of acoustic waves. -4 3b, as shown by a foam pad having a resistance to the passage of air of less than 100 .mu.m.

[0047] According to the variant shown in FIG. 3 c , the plate 6 is not covered by a layer of foam that merges into the entire volume of the block 10 .

[0048] According to the variant shown in FIG. 3 d, the plate 6 is arranged between the cavity 11 and the auxiliary cavity 20, said plate being fixed by its peripheral edge 13 to a lip 21 molded from the block 10, said lip surrounding said plate so as to allow an accentuated decoupling between said plate and the frame 2.

[0049] Although not shown, in all variations of the third embodiment, an ultra-compressible gasket (having higher compressibility than the foam of block 10) can be fitted between the periphery 13 of plate 6 and the periphery of opening 22 for improved decoupling at very low frequencies, especially below 100 Hz.

[0050] Finally, an assembly for generating anti-noise in a passenger compartment of a motor vehicle is described; The assembly comprises the headrest 1 as described above and an anti-noise generating system connected to at least one transducer 7 .

[0051] In one variant, the transducer 7 can be used to generate conventional noise, such as music, instead of anti-noise. [Brief description of the drawings]

[0052] [Figure 1a] FIG. 1 is a schematic exploded perspective view of a headrest according to a first embodiment. [Figure 1b] FIG. 1 is a schematic non-exploded perspective view of a headrest according to a first embodiment. [Figure 2a] FIG. 11 is a schematic exploded perspective view of a headrest according to a second embodiment. [Figure 2b] FIG. 11 is a schematic non-exploded perspective view of a headrest according to a second embodiment. [Figure 3a] FIG. 11 is a schematic partial cross-sectional view of a headrest according to a modified example of the third embodiment. [Figure 3b] FIG. 11 is a schematic partial cross-sectional view of a headrest according to a modified example of the third embodiment. [Figure 3c] FIG. 11 is a schematic partial cross-sectional view of a headrest according to a modified example of the third embodiment. [Figure 3d] FIG. 11 is a schematic partial cross-sectional view of a headrest according to a modified example of the third embodiment.

Claims

1. A headrest (1) for a motor vehicle seat, comprising: the headrest comprises a rigid structure for mounting the headrest to an upper portion of the seat back; The headrest has at least one sound transmitting plate (6) attached to the structure, The plate is An electrodynamic transducer (7) is provided, A headrest connected to said structure via acoustic decoupling means (8) made of an elastically deformable material so as to prevent the transmission of vibrations from said plate to said structure.

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

3. The structure comprises: A frame (2) comprising two parallel metal rods (3); a part (4) for receiving a cushion (5) and absorbing energy upon impact of said head of an occupant, The rods are each telescopically housed in a respective housing (16) provided within the component; the part has a general profile defining an inverted U-shaped cross section in side view so as to define a cavity (18); 3. A headrest according to claim 1 or 2, characterized in that at least one transducer (7) is housed in the cavity.

4. The decoupling means (8) are integral and extend laterally on both sides within the cavity (18); 4. A headrest according to claim 2 or 3, characterized in that two plates (6), each equipped with a transducer (7), are fixed to the lateral ends of said means.

5. said rods (3) each receiving a respective decoupling means (8) disposed in said cavity (18); A headrest according to claim 2 or 3, characterized in that the decoupling means (8) each receive a plate (6) on which a transducer (7) is mounted.

6. The structure is formed by a metal frame (2), 3. Headrest according to claim 1 or 2, characterized in that at least one plate (6) on which a transducer (7) is provided is connected to the frame via decoupling means (8).

7. A pad block (10) made of resiliently compressible foam is provided; The block is provided with at least one cavity (11), said cavity has an opening (22) which is closed at its periphery by a plate (6) fixed by said periphery (13); A headrest according to any one of the preceding claims, characterized in that the decoupling means (8) are formed by the foam of the block interposed between the frame (2) and the plate.

8. said plate (6) is covered, facing said cavity (11), by a layer of foam (23) that blends into the entire volume of said block (10); The layer comprises: The block is molded or molded with a porosity of greater than 0.95 and a strength of 5000 N·s·m to improve the passage of acoustic waves. －４ 8. Headrest according to claim 1, characterized in that it is formed by a foam pad having a resistance to the passage of air of less than 0.1 mm.

9. 1. An assembly for generating anti-noise in a passenger compartment of a motor vehicle, comprising: The assembly comprises a headrest (1) according to any one of claims 1 to 8 and an anti-noise generating system connected to at least one transducer (7).

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