Vehicle seat back

Abstract

A backrest (16) of a vehicle seat (10) comprises a backrest frame (17), a rear trim element (48) attached to the backrest frame (17), two side cushions (36, 38), each side cushion (36, 38) comprising a side foam block (42, 44) covered with a respective side cover (37, 39), the side covers (37, 39) and the rear trim element (48) constituting an integral subassembly (100). Abstract Figure: [Fig. 6]

Description

Title of the invention: Vehicle seat back Technical field

[0001] The present description relates to a vehicle seat back, in particular a motor vehicle seat back. Also described is a vehicle seat comprising such a back, a method of mounting a vehicle seat back and a vehicle seat comprising such a back. Prior art

[0002] In the automotive field, in particular, it is known to produce a vehicle seat back by covering a back frame with foam. The whole is then covered with a cover.

[0003] The seat backrest can integrate numerous comfort and / or safety functions. To do this, it is known to fix a support to the backrest frame, to mount the various elements necessary for achieving the comfort and / or safety functions on the support or on the backrest frame, then to cover the assembly thus obtained with foam. A cover then covers the assembly.

[0004] Thus, depending on the number and complexity of the functions to be integrated into the back of a seat, the assembly of a back can be very different on an assembly line.

[0005] Furthermore, the assembly of such a file is generally carried out at least in part by an operator, who must therefore be capable of assembling the different variants of the same file.

[0006] There is therefore a need for a seat back that can be mounted in a substantially identical manner regardless of the functions it incorporates, with a substantially constant assembly time.

[0007] There is also a need for a seat back that is easily produced on an assembly line.

[0008] The present description aims to provide a solution to at least some of the needs mentioned above. Summary

[0009] To this end, a vehicle seat back is described comprising a back frame, a rear trim element attached to the back frame, two side cushions, each side cushion comprising a side foam block covered with a respective side cover, the side covers and the rear trim element constituting an integral subassembly.

[0010] Thus, the side cushions of such a seat back are easily produced.

[0011] According to preferred embodiments, the vehicle seat back comprises one or more of the following features, taken alone or in combination: - the rear trim element is a rear panel; - the rear panel is at least partly flexible; - the back panel is at least partly made of foam, preferably covered with a skin; - the rear panel is obtained in: — forming an outer layer by applying at least one layer of paint against a first forming surface of a forming tool; — applying a skin, preferably made of water-free synthetic material, especially water-free polyurethane, against an inner surface of the outer layer; and — applying a layer of foam against an internal surface of the skin, the layer of foam having a formulation containing water and a foaming catalyst at the time of its application to the skin; - the rear panel includes an insert overmolded with foam; - the rear upholstery element is a veil, preferably fixed to the backrest frame; - each side cover is sewn to the rear trim element, in particular on the rear panel or the veil, if applicable; - each side cover is fixed to fixing reliefs of the rear trim element, in particular of the rear panel insert where applicable; - each side cover is attached to the backrest frame fixing reliefs; - the rear panel, in particular the insert where applicable, includes reliefs for fixing to the backrest frame, in particular elastic fitting reliefs; - each side foam block is held in position around a respective upright of the backrest frame by means of the respective side cover, preferably only by means of the respective side cover; - each side foam block is folded to at least partially cover three separate faces of the associated upright of the backrest frame, in particular one face of the upright facing the front of the vehicle seat, one face of the upright facing the other upright, and one face of the upright facing in the direction opposite the other upright; - the vehicle seat backrest further comprises at least one central upholstery module, arranged between the two side cushions, the central upholstery module preferably being adapted to be fixed to the backrest frame independently of the side cushions, the central upholstery module preferably being fixed to the backrest frame independently of the side cushions; - the central trim module includes a trim independent of the side cushions; - the central upholstery module comprises at least one support, fixed to the backrest frame, and a central foam block covering all or part of the support; - at least one side cushion comprises a side airbag device, fixed to a pillar of the backrest frame and surrounded at least partially by the foam block of said side cushion; and - the rear panel comprises a skin, preferably made of synthetic material, in particular water-free polyurethane, the skin being covered on a first face with at least one layer of paint, the skin being secured, by a second face opposite the first face, to a layer of foam, the layer of foam preferably being made of polyurethane containing water.

[0012] According to another aspect, there is also described a motor vehicle seat comprising a seat with a seat frame and a backrest as described above in all its combinations, the backrest frame being fixed to the seat frame, preferably so as to be able to pivot around a transverse axis.

[0013] According to yet another aspect, there is described a method of manufacturing a motor vehicle seat backrest as described above in all its combinations, comprising the steps of: (i) provide a backrest frame; (ii) provide an integral sub-assembly, consisting of a rear trim element and two side cushion covers; iii) fix the rear trim element to the backrest frame; iv) filling each side cover with at least one block of foam at least partially surrounding an upright of the backrest frame to form two side cushions, step iv) preferably being carried out after step iii).

[0014] Step ii) may comprise the sub-steps of: a) produce a rear trim element; b) provide two side covers; c) fix the two side covers on the rear trim element.

[0015] Step a) may comprise the sub-steps consisting of: - forming an outer layer by applying at least one layer of paint against a first forming surface of a production tool; - applying a skin, preferably made of water-free synthetic material, in particular water-free polyurethane, against an inner surface of the outer layer; and - applying a layer of foam against an internal surface of the skin, the layer of foam having a formulation containing water and a foaming catalyst time of its application to the skin.

[0016] The skin may be made of substantially non-cellular polyurethane.

[0017] The foam layer may be a cellular polyurethane foam.

[0018] A method of manufacturing a vehicle seat is also described, comprising the steps of: - provide a seat with a seat frame; - build a file by implementing the process described above in all its combinations; and - fix the backrest to the seat, preferably in such a way that the backrest can pivot around an axis transverse to the seat. Brief description of the drawings

[0019] Other characteristics and advantages will appear during the following description of one of its embodiments, given by way of non-limiting example, with reference to the attached drawings. In the drawings:

[0020] [Fig.l] schematically represents a side view of an example of a vehicle seat;

[0021] [Fig.2] schematically represents in perspective the back of the vehicle seat of [Fig.l];

[0022] [Fig.3] schematically represents an exploded view of the vehicle seat back of [Fig.2];

[0023] [Fig.4] schematically represents in perspective the frame of the vehicle seat back of [Fig.2] and [Fig.3];

[0024] [Fig.5] schematically represents a perspective view of an exemplary subassembly of a rear trim element and side covers for side cushions that can be implemented in the vehicle seat back of [Fig.2] and [Fig.3];

[0025] [Fig.6] schematically illustrates in section the subassembly of [Fig.5] mounted on the backrest frame of [Fig.4], the foam blocks of the side cushions being inserted into the side covers;

[0026] [Fig.7] schematically illustrates the subassembly of [Fig.5] fixed on the backrest frame of [Fig.4];

[0027] [Fig.8] schematically illustrates in section a detail of the subassembly of [Fig.5] mounted on the backrest frame of [Fig.4], a foam block of the illustrated side cushion being inserted into the corresponding side cover, a side airbag device being fixed on the upright of the frame;

[0028] [Fig.9] schematically illustrates in section a rear panel which can be implemented in the subassembly of [Fig.5];

[0029] [Fig. 10] illustrates a first step of an example of a method for producing the rear panel of [Fig.9];

[0030] [Fig. 11] illustrates a second step of an example of a method for producing the rear panel of [Fig.9];

[0031] [Fig.12] illustrates a third step of an example of a method for producing the rear panel of [Fig.9];

[0032] [Fig. 13] schematically illustrates a first step of a method for producing another example of a vehicle seat back; and

[0033] [Fig. 14] schematically illustrates a second step of the process, the first step of which is illustrated by [Fig. 13]. Description of the embodiments

[0034] In the various figures, the same references designate identical or similar elements. For the sake of brevity, only the elements which are useful for understanding the embodiment described are shown in the figures and are described in detail below.

[0035] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "rear", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures or of a vehicle seat in its normal position of use.

[0036] In particular, the longitudinal direction X means the longitudinal direction of the seat. The longitudinal direction of the seat is considered to be the same as the longitudinal direction of the motor vehicle in which the seat is mounted. This longitudinal direction X corresponds to the normal direction of travel of the vehicle. The longitudinal direction X is horizontal. The transverse direction Y of the seat thus corresponds to the transverse or lateral direction of the motor vehicle. This transverse direction corresponds to a direction perpendicular to the normal direction of travel of the vehicle. The transverse direction Y is horizontal. Finally, the vertical direction Z is a vertical direction of the seat, perpendicular to the longitudinal and transverse directions.

[0037] [Fig.l] schematically represents a motor vehicle seat 10 mounted on a sliding mechanism 12.

[0038] The seat 10 comprises a seat 14, with a seat frame 15, on which a backrest 16, with a backrest frame 17, is mounted. The backrest frame 17 is here pivotable about an axis 18 transverse to the seat frame 15. To do this, a hinge mechanism 20 is arranged between the seat frame 15 and the backrest frame 17.

[0039] The seat 14 is mounted on movable profiles 22, also called slides or male profiles, by means of feet 24, 26. Each movable profile 22 is part of a slide 12 and is associated with a fixed profile 28. The fixed profile 28 is also called a rail or female profile. The fixed profile 28 is fixed to the floor 30 of a motor vehicle.

[0040] The seat 10 comprises in this example a manual control element 32, called a lever, for controlling the sliding of the slides 12. This manual control element 32 makes it possible in particular to block and unlock systems for stopping the sliding of the movable profiles 22 relative to the respective fixed profiles 28. Once the stop systems are unlocked, the manual control element 32 can also be used to slide the movable profiles 22 relative to their respective fixed profiles 28 of the slide 12 in the longitudinal direction X of the slides 12. The fixed profiles 28 and movable profiles 22 of the slides 12 are generally metallic.

[0041] Alternatively, the movement of the movable profiles 22 relative to the fixed profiles 28 is controlled by means of an actuator.

[0042] According to the illustrated example, the seat 10 may also comprise a headrest 34, with a headrest frame 35, partially visible in [Fig. 2], in the form of rods 35 fixed to the backrest frame 17.

[0043] In the following, the backrest 16 of the vehicle seat 10 is described in more detail.

[0044] As can be seen in [Fig.2] in particular, the illustrated file 16 comprises essentially a first side cushion 36, a second side cushion 38 and a central trim module 40, such that the first and second side cushions 36, 38 are each arranged on a respective side of the central trim module 40. The central trim module 40 here comprises a foam block 46, the only visible element of the central trim module 40 in [Fig.l]. In practice, the foam block 46 may be covered with a cover. The cover of the foam block 46 is preferably independent of the cover 37, 39 of the side cushions 36, 38.

[0045] In the example illustrated, the central upholstery module 40 forms the support face of the bowl of the backrest 16, that is to say the central support part of the back of the occupant of the seat, while the side cushions 36, 38 form the lateral portions projecting relative to the bowl of this same support face of the back of the occupant of the seat.

[0046] It should be noted here that the central upholstery module 40 pre-exists its attachment to the backrest frame 17. Thus, the central upholstery module 40 is not produced by overmolding the backrest frame 17 and / or structural elements already secured to the backrest frame 17. This does not prevent the foam block 46 of the central upholstery module 40 from being produced by overmolding a possible support of the central trim module 40. However, this overmolding is carried out prior to fixing the support in question on the backrest frame 17.

[0047] The backrest 16 further comprises a rear trim element 48, defining the greater part of the rear face of the backrest 16, or even the entire rear face of the backrest 16.

[0048] The backrest 16 also comprises, according to the example illustrated, an upper finishing element 50. The finishing element 50 here surrounds the support rods 35 of the headrest 34.

[0049] The central upholstery module 40 is here fixed to the backrest frame 17, independently of the side cushions 36, 38, and vice versa. In other words, the central upholstery module 40 can be fixed to the backrest frame 17 while the side cushions 36, 38 are not fixed to the backrest frame 17, and vice versa. Thus, the central upholstery module 40 is able to be fixed to the backrest frame 17 independently of the two side cushions 36, 38. Similarly, the two side cushions 36, 38 are adapted to be fixed to the backrest frame 17, independently of the central upholstery module 40. The central upholstery module 40 can however be fixed to one and / or the other of the side cushions 36, 38.However, preferably, the central trim module 40, on the one hand, and the side cushions 36, 38, on the other hand, are independent in that there is no direct attachment of the central trim module 40 to a side cushion 36, 38 or, conversely, of a side cushion 36, 38 to the central trim module 40. The foam block 46 of the central trim module 40 can, however, be mounted clamped between the side cushions 36, 38.

[0050] The rear trim element 48 may also be directly fixed to the backrest frame 17, preferably independently of the central trim module 40. The rear trim element 48 may be fixed to the backrest frame 17 by any suitable means, in particular by screwing or riveting. According to yet another example, the rear trim element 48 is elastically fitted onto the backrest frame 17. Advantageously, the rear trim element 48 is adapted to be fixed to the backrest frame 17 before or, preferably, after fixing the central trim module 40. This may in fact allow access from the rear of the seat 10 to the various elements of the central trim module 40 to be functionally connected, after the central trim module 40 has been fixed to the backrest frame 17, before fixing the rear trim element 48.

[0051] The finishing element 50 is fixed, according to the example illustrated, on the central trim module 40. This finishing element 50 can be fixed to the central trim module 40 by any suitable means, accessible to those skilled in the art. In particular, the finishing element 50 can be elastically fitted onto the foam block 46 of the central trim module 40.

[0052] As illustrated in [Fig.4], the backrest frame 17 essentially comprises a first upright 17i, a second upright 172, a first crosspiece 173, hereinafter referred to as the “lower crosspiece 173”, and a second crosspiece 174, hereinafter referred to as the “upper crosspiece 174”. The uprights 174, 172 and the crosspieces 173, 174 form a backrest frame 17 in the form of a frame. To do this, the uprights 174, 172, and the crosspieces 173, 174 may be fixed together, in particular welded together. Alternatively, the backrest frame 17 is a single piece, for example being molded.

[0053] The central upholstery module 40 is fixed to the backrest frame 17.

[0054] The central trim module 40 essentially comprises a support 54, for example in the form of a plate. The support 54 is notably more rigid than the foam block 46 of the central trim module 40. The foam block 46 of the central trim module 40 is fixed on the support 54. In particular, the foam block 46 can be overmolded on the support 54. Alternatively, the foam block 46 can be glued or elastically fitted onto the support 54, the foam block 46 preferably having plastic inserts in the latter case, forming elastic fitting reliefs on the support 54.

[0055] The support 54 extends essentially in a longitudinal direction. The longitudinal ends of the support 54 may be curved. Thus, the upper end of the support 54 may rest on the upper crosspiece 174 of the backrest frame 17. Similarly, the lower end of the support 54 may receive the lower crosspiece 173 of the backrest frame 17. The upper and lower ends of the support 54 may have means for fixing to the lower crosspieces 173 and upper 174, respectively, of the backrest frame 17. These fixing means may in particular comprise: - additional reliefs, for example for force-fitting the central upholstery module 40 onto the backrest frame 17; and / or - corresponding holes for fixing using screws, bolts or rivets, for example; and / or - additional elastic fitting reliefs (or clips), for fixing by elastic fitting. This latter solution appears to be the most favorable, limiting the number of parts and manipulations necessary to fix the support 54 to the backrest frame 17.

[0056] The support 54 may be equipped with different elements each associated with one or more comfort functions for the occupant of the seat 10, such as a fan, to ventilate the occupant of the seat, or inflatable pockets connected to a pump, to massage the occupant of the seat. Other comfort functions may be associated with the support 54. In particular one or more loudspeakers and / or one or more vibrating devices. (from the English "exciter") and / or one or more resistive wires for heating the back of the occupant of the vehicle seat 10 can be fixed on the support 54. Preferably, the speaker(s) and / or the vibrating device(s) and / or the resistive wire(s) are arranged between the support 54 and the foam block 46 of the central trim module 40 or at least partially received in the foam block 46 of the central trim module 40.

[0057] In the following, the production of the side cushions 36, 38 is described in more detail from an integral subassembly 56, consisting of the rear trim element 48 and the respective side covers 37, 39 of the side cushions 36, 38. More precisely, the side covers 37, 39 of the side cushions 36, 38 are here fixed to the rear trim element 48, in particular are sewn to the rear trim element 48.

[0058] Here, the rear trim element 48 comprises a rigid insert 58, onto which a foam block 60 is overmolded. The foam block 60 may be more or less flexible. The rear trim element 48 thus takes the form of a rear panel 62. A skin may be provided on the rear face of the foam block 60, intended to be visible to the occupants of the motor vehicle, when the rear trim element 48 is fixed to the backrest frame 17. In particular, the skin may be present in the bottom of the mold used to overmold the foam block 60 onto the insert 58.

[0059] As can be seen in [Fig.5] and [Fig.6] in particular, the insert 58 forms first reliefs 64 for fixing the rear trim element 48 to the backrest frame 17. The insert 58 thus ensures the fixing of the rear trim element 48 to the backrest frame 17. Here, the insert 58 forms first reliefs 64 for fixing on each of the uprights 17i, 172 and on each of the crosspieces 173, 174 of the backrest frame 17. Alternatively, however, the rear trim element 48 may be fixed only to the uprights 17i, 172 or only to the crosspieces 173, 174 of the backrest frame 17. The rear trim element 48 may also be fixed to both uprights 174, 172 of the backrest frame 17 and to a single of the two crosspieces 173, 174, in particular, only to the upper crosspiece 174. The first fixing reliefs 64 may in particular be elastic fitting reliefs.

[0060] The insert 58 also forms second reliefs 66 for fixing the side covers 37, 39. The second reliefs 66 here protrude relative to the rest of the insert 58. The second reliefs 66 make it possible to stretch each side cover 37, 39 surrounding the side foam block 42, 44 of the respective cushion 36, 38.

[0061] The side covers 37, 39 are here sewn onto the rear trim element 48, more precisely here onto the foam block 60 overmolded onto the insert 58. The side covers 37, 39 are thus made integral with the rear trim element 48. Other means of fixing the side covers 37, 39 to the rear trim element 48 can be implemented. In particular, the side covers 37, 39 can be glued to the rear trim element 48.

[0062] Each side cover 37, 39 here forms reliefs 68 complementary to the second reliefs 66 of the insert 58. Here, the reliefs 68 of the covers 37, 39 take the form of holes adapted to receive the second reliefs 66 of the insert 58.

[0063] Each side cushion 36, 38 further comprises a respective foam block 42, 44. Here the foam blocks 42, 44 are distinct or independent. Advantageously, each foam block 42, 44 is in particular devoid of any means of attachment to the backrest frame 17, in particular to the respective upright 17i, 172 of the backrest frame, to the associated cover 37, 39 and / or to the rear upholstery element 48 in particular to the first and second reliefs 64, 66 of the insert 58. The foam blocks 42, 44 are also distinct and independent of the foam block 46 of the central upholstery module 40.

[0064] Each foam block 42, 44 is thus preferably held in position solely by the associated side cover 37, 39 and upright 17i, 172 of the backrest frame 17, the side cover 37, 39 being stretched around the associated foam block 42, 44. In particular, each foam block 42, 44 may be arranged to at least partially cover three faces of the associated upright 17b, 172, in particular the faces facing toward the front of the vehicle seat 10, toward the other upright 172, 17i of the backrest frame 17, and in the direction opposite to the other upright 172, 17i.

[0065] As illustrated in [Fig.8], a safety airbag device 70 may be attached to one and / or the other of the uprights 17i, 172 and be covered by the associated foam block 42, 44 of the side airbag 36, 38.

[0066] The file 16 as just described is particularly simple to manufacture.

[0067] Thus, a method of manufacturing such a backrest 16 may comprise a first step consisting of providing a backrest frame 17, an integral subassembly 56, consisting of the rear trim element 48 and the side covers 37, 39. At this step, the backrest frame 17 may possibly already be fixed to the seat frame 15 and / or have already received the headrest frame 35 in whole or in part. In particular, the support rods of the headrest may already be fixed to the backrest frame 17.

[0068] In a second step, the rear trim element 48 is fixed to the backrest frame 17, here by means of the first reliefs 64 for fixing the insert 58 of the rear trim element 48.

[0069] Once the rear trim element 48 is fixed to the backrest frame 17, each foam block 42, 44 is placed around the respective upright 17i, 172 and then the foam block 42, 44 is covered with the associated side cover 37, 39. By fixing the side cover 37, 39 to the rear trim element 48 here by means of the second reliefs 66 of the insert 58, the foam block 42, 44 is held in position in the side cushion 36, 38. In fact, each side cover 37, 39 is then stretched around the associated foam block 42, 44.

[0070] The central upholstery module 40 can then be fixed to the backrest frame 17. Alternatively, the central upholstery module 40 is fixed to the backrest frame 17 before the rear upholstery element 48. It is also conceivable to fix the rear upholstery element 48, then the central upholstery module 40 before fixing the side covers 37, 39 in order to hold the foam blocks 42, 44 in position.

[0071] Finally, according to the example illustrated, the finishing element 50 is fixed.

[0072] Thus, the assembly of the seat 10, in particular the backrest, is very simple to carry out. Furthermore, it can be identical or substantially identical, whatever the functions integrated or not in the backrest 16, which are mainly carried by the central upholstery module 40. The assembly line for such a range of seats is thus simpler and easier to manage.

[0073] In the following, variants of the rear trim element 48 that can be implemented in the subassembly 56 that has just been described are described, as well as methods of manufacturing such a rear trim element 48.

[0074] [Fig. 9] illustrates a variant of the panel 62 described previously. The panel 62 comprises an inner surface 62b intended to be oriented towards the inside of the seat 10, and an outer surface 622, opposite the inner surface 62i and intended to be oriented towards the outside of the seat 10. Thus, the outer surface 622 is a surface at least partly visible from the outside of the seat 10.

[0075] The panel 62 comprises, as illustrated in [Fig.9], an outer layer 72, a skin 74 and a foam layer 76.

[0076] The outer layer 72 forms the outer surface 622 of the panel 62, that is to say, in this case, the back of the backrest 16. The outer layer 72 is for example formed by at least one layer of paint making it possible to give a particular appearance to the outer surface 622 of the panel 62. It is understood that in the present application, the term “layer of paint” means a layer of paint or varnish. In particular, it is possible to choose the color and / or the gloss of the at least one layer of paint to obtain a particular appearance. The paint used is for example a water-based paint or a paint based on another chemical solvent. The outer layer 72 has for example a thickness of between 5 μm and 120 μm, preferably between 10 μm and 80 μm, for example approximately 25 μm. It is understood that the outer layer 72 may comprise several layers of paint, depending on the appearance and / or other properties desired for the outer layer 72.Thus, the outer layer 72 may in particular have anti-abrasive properties, resistance to wear, light, and chemicals. The outer layer 72 may also have a pattern, such as graining, a logo, or other, this pattern being able to be formed on the layer. external 72 during the production of panel 62, as will be described later.

[0077] The skin 74 is for example made of synthetic material. The skin 74 extends over the inner surface of the outer layer 72. The skin 74 thus forms a support for the outer layer 72 by adhering to it. The skin 74 has an outer surface, extending over the inner surface of the outer layer 72, and an inner surface, opposite the outer surface. The skin 74 forms a substantially rigid or semi-rigid shell of the panel 62.

[0078] For this purpose, the skin 74 is here formed from a synthetic material devoid of water. More particularly, the skin 74 may be a layer of foam having few or no cells, or non-cellular foam. In other words, the skin 74 contains few or no air bubbles, which gives it a certain rigidity. In practice, the skin 74 may contain a limited number of air bubbles, called residual air bubbles, the presence of which is due to the method of applying the skin 74 which will be described later.

[0079] The skin 74 is for example made of an elastomeric material, for example a material resulting from a polyol-isocyanate reaction. According to one embodiment, the skin 74 is made of substantially non-cellular, water-free polyurethane. Thus, the skin 74 exhibits behavior similar to a plastic-coated textile (PET) or imitation leather.

[0080] The skin 74 has for example a thickness of between 0.1 mm and 3 mm, preferably between 0.5 mm and 2 mm. The skin 74 may have a variable thickness depending on the characteristics desired for the rear panel 62, in particular in terms of rigidity. The skin 74 has for example a density of between 400 kg.m3 and 1500 kg.m3, preferably between 800 kg.m3 and 1200 kg.m 3. The skin 74 may have a tensile strength of between 1 Mpa and 50 Mpa, preferably between 3 Mpa and 15 Mpa, measured according to the method DIN EN ISO 527-3 / 2 / 100. The skin 74 has, for example, a tear strength of between 0.5 N.mm 1 and 30 N.mm ', preferably greater than 4 N.mm ', preferably greater than 6 N.mm ', measured according to the DIN EN ISO 13937-2 method.

[0081] The foam layer 76 extends over the inner surface of the skin 74 and adheres thereto. The foam layer 76 has an outer surface, extending over the inner surface of the skin 74, and an inner surface, opposite the outer surface. The foam layer 76 forms a cushioning of the rear panel 62. The foam layer 76 thus has a certain flexibility. In particular, the foam layer 76 is more flexible than the skin 74.

[0082] The foam layer 76 is for example made of a synthetic material having a formulation containing water. More particularly, the foam layer 76 is a cellular foam layer, i.e. a foam layer containing air bubbles, in particular a large number of air bubbles. The cells of the foam layer 76 are obtained during the chemical reaction making it possible to obtain the foam layer 76 as will be described later.

[0083] The foam layer 76 is for example made of an elastomeric material, for example a material resulting from a polyol-isocyanate reaction using a foaming catalyst. The foam layer 76 is thus for example made of a polyurethane foam containing water.

[0084] The foam layer 76 may have a thickness of between 1 mm and 15 mm, preferably between 4 mm and 9 mm. It should be noted that the foam layer 76 may have a variable thickness depending on the desired characteristics of the rear panel 62, in particular in terms of flexibility. The foam layer 76 has, for example, a rigidity of between 3N / 30mm and 45N / 30mm, preferably between 3N / 30mm and 25N / 30mm.

[0085] As can be seen in [Fig.9], the foam layer 76 may be integral with the first and second fixing reliefs 64, 66 described previously. In particular, each first or second fixing relief 64, 66 may be formed from a separate insert, fixed to the foam layer 76. Each insert may be fixed to the foam layer 76 by overmolding the foam layer 76 onto the insert in question. Alternatively, the first and second fixing reliefs 64, 66, or at least some of them, may be integral with each other, in particular by being formed by a single insert.

[0086] A rear panel 62 as described above has a satisfactory appearance on its outer surface. Such a rear panel 62 may also be sufficiently flexible to allow the covers 37, 39 of the cushions 36, 38 to be fixed to the rear panel 62, in particular by sewing.

[0087] An example of a method for producing such a rear panel 62 is described below, with reference to [Fig.10], [Fig.11] and [Fig.12].

[0088] The rear panel 62 is produced in a production tool 78 shown in [Fig. 10], [Fig. 11] and [Fig. 12]. The production tool 78 is for example a mold, having two complementary parts 78i, 782.

[0089] The different steps of the method described below can be carried out while the production tool 78 is heated, in particular the first part 78i, for example to a temperature close to 70°C.

[0090] The outer layer 72 is produced by applying at least one layer of paint to a first forming surface 80 so that the outer layer 72 adopts the shape of the first forming surface 80, as shown in [Fig. 10]. The application of the layer of paint is done for example by spraying. When the outer layer 72 comprises several layers of paint, these are applied successively on the first forming surface 80 from the outside to the inside. In other words, the layer forming the outer surface, for example a first layer of paint, is applied first on the first forming surface 80 then the layer extending immediately against this first layer, for example a layer of paint defining the color of the outer surface, is applied against the first layer covering the first forming surface 80. Heating the first forming surface 80 makes it possible to obtain rapid drying of the outer layer 72.

[0091] A release agent may first be applied to the first forming surface 80, before the outer layer 72 is formed. In this case, the layer(s) of paint are applied to the release agent coating the first forming surface 80.

[0092] The skin 74 is then applied against the inner surface of the outer layer 72, as shown in [Fig.l 1]. The skin 74 is applied, for example, by spraying the material forming the skin 74 against the inner surface of the outer layer 72. The skin 74 is for example applied to the outer layer 72 while the outer layer 72 is not yet dry, in order to ensure adhesion between the skin 74 and the outer layer 72. The material of the skin 74 is maintained in a viscous state after its application and before the application of the foam layer 76, for example due to the heating of the first part 78i of the production tool 78.

[0093] The foam layer 76 is then applied to the inner surface of the skin 74.

[0094] According to the example illustrated in [Fig. 12], the foam layer 76 is previously formed on a functional film 82 before being applied with the functional film 82 to the inner surface of the skin 74. The functional film 82 is for example a transfer film. The application of the foam layer 76 to the functional film 82 is for example carried out while the functional film 82 is stretched in a frame 84 by applying a foam precursor material to one of the faces of the functional film 82. The foam precursor material makes it possible to form the foam layer 76 by chemical reaction, in particular thanks to a foaming catalyst, as described previously. The chemical reaction creates a cellular foam on the face of the functional film 82.The assembly formed by the foam layer 76 and by the functional film 82 is then applied to the inner surface of the skin 74, preferably while the foam layer 76 is in the viscous state. The foam precursor material is for example applied by spraying onto the functional film 82. When the functional film 82 is a transfer film, intended to be removed after the adhesion of the foam layer 76 to the skin 74, the inner surface of the foam layer 76 is applied to the functional film 82, as shown in [Fig. 12], and the outer surface of the foam layer 76 is applied to the inner surface of the skin 74. Alternatively, for a functional film 82 other than a transfer film, the film . functional film 82 can extend over the outer surface of the foam layer 76 and be applied to the inner surface of the skin 74 so as to be permanently fixed in the back panel 62. In any case, when the application is made while the skin 74 is in the viscous state, adhesion is ensured between the foam layer 76, also in the viscous state, or with the functional film 82.

[0095] As illustrated in [Fig. 12], the foam layer 76 may be overmolded onto the first and / or second fixing reliefs 64, 66. If necessary, the functional transfer film 82 may extend around the first and / or second fixing reliefs 64, 66.

[0096] According to the embodiment shown in [Fig. 12], the assembly formed by the foam layer 76, the first and / or second fixing reliefs 64, 66 and the functional film 82, if applicable, is preformed before application to the internal surface of the skin 74 to acquire the shape of the inner surface of the rear panel 62. In this case, this assembly is placed against a second forming surface 86 of the second part 782 of the production tool 78. The second forming surface 86 here has the shape of the inner surface of the rear panel 62. The second part 782 of the production tool 78, in particular the second forming surface 86, can be heated.

[0097] The rear panel 62 is then produced by bringing the second part 782 closer to the tool 78 for producing the first part 78i so as to make the foam layer 76 adhere to the internal surface of the skin 74. After cooling and hardening of the skin 74 and the foam layer 76, the rear panel 62 forms a coherent assembly.

[0098] The first and second parts 78i, 782 of the production tool 78 can then be separated and the rear panel 62 can be removed from the production tool 78. This operation is facilitated when a release agent has been applied to the first forming surface 80. When the functional film 82 is a transfer film, this is removed from the inner surface of the foam layer 76 after the outer surface of the foam layer 76 has been applied to the inner surface of the skin 74.

[0099] The covers 37, 39 can then be fixed, in particular sewn, onto the rear panel 62.

[0100] As an alternative to the example illustrated in [Fig. 12], the foam layer 76 may be first applied to the internal surface of the skin 74 then the second part 782 of the production tool 78 is brought closer to the first part 78i so as to apply the second forming surface 86 to the internal surface of the foam layer 76 or of the functional film 82, as the case may be, in order to give its shape to the foam layer 76 to secure this foam layer 76 to the skin 74.

[0101] The production method described above thus makes it possible to obtain a finished rear panel 62 in one operating cycle of the production tool 78. The production method However, this method is susceptible to numerous variations accessible to those skilled in the art.

[0102] [Fig. 13] and [Fig. 14] illustrate a variant, in which the rear trim element 48 is constituted by a web 88, in particular a textile web (or curtain), and fixing supports 90 for the web 88. The web 88 is fixed to the backrest frame 17, in particular to the uprights 17i, 172, by means of the fixing supports 90, themselves fixed to the web 88. For example, the web 88 is sewn or glued to the fixing supports 90. Alternatively, the web 88 defines housings for receiving the fixing supports 90. Each fixing support 90 forms for example a fixing relief, for example an elastic fitting relief, to the backrest frame 17, in particular to an upright 17i, 172 of the backrest frame 17.

[0103] Here, the side covers 37, 39 are also fixed to the fixing supports 90. Alternatively, the side covers 37, 39 are fixed to the web 88, in particular are sewn or glued to the web 88.

[0104] In order to hold each foam block 42, 44 in position, the associated side cover 37, 39 here comprises hooks 92 received in holes in the fixing supports 90. Each side cover 37, 39 is thus stretched around the associated foam block 42, 44.

[0105] The present invention is not limited to the examples described above. On the contrary, the invention is susceptible to numerous variants accessible to those skilled in the art.

[0106] Thus, in the example illustrated, the central upholstery module 40 comprises a support and a foam block fixed to the support. Alternatively, the central upholstery module may be without a support, or even only comprise a foam block. When the central upholstery module is without a support as described above, it may comprise rigid inserts, incorporated into the foam block, to facilitate its attachment to the backrest frame. Such inserts may be incorporated by overmolding the corresponding foam block onto these inserts. By “rigid” is meant here that the inserts are in particular more rigid than the foam.

[0107] The support 54 of the central trim module 40 may also take other forms than that described above. In particular, the support 54 may be a frame comprising two crosspieces, preferably rigid, and two uprights, rigid or flexible, spring elements, in particular elastic wires extending between the crosspieces and / or between the uprights.

[0108] The order of fixing of the central trim module 40 and of the subassembly formed by the rear trim element 48 and the side covers 37, 39 may depend on the geometry of the backrest frame 17, of the support 54 of the central trim module 40 and of their fixings on the backrest frame 17, in particular.

[0109] The rear trim element 48 may take other shapes than those indicated previously. In particular, the rear trim element 48 may take the form of a shell.

[0110] The side covers 37, 39 may be attached to the rear trim element by any means accessible to those skilled in the art, other than the gluing or sewing already mentioned previously.

Claims

Claims

1. A backrest (16) of a vehicle seat (10) comprising a backrest frame (17), a rear trim element (48) attached to the backrest frame (17), two side cushions (36, 38), each side cushion (36, 38) comprising a side foam block (42, 44) covered with a respective side cover (37, 39), the side covers (37, 39) and the rear trim element (48) constituting an integral subassembly (100).

2. A vehicle seat back according to claim 1, wherein the rear trim member (48) is a rear panel (62).

3. A vehicle seat back according to claim 2, wherein the rear panel (62) is at least partly flexible.

4. A vehicle seat back according to claim 3, wherein the rear panel (62) is at least partly made of foam, preferably covered with a skin.

5. A vehicle seat backrest according to claim 4, wherein the rear panel (62) is obtained by: - forming an outer layer (72) by applying at least one layer of paint against a first forming surface (80) of a forming tool (78); - applying a skin (74), preferably made of water-free synthetic material, in particular water-free polyurethane, against an inner surface of the outer layer (72); and - applying a foam layer (76) against an inner surface of the skin (74), the foam layer (76) having a formulation containing water and a foaming catalyst at the time of its application to the skin (74).

6. Vehicle seat backrest according to one of claims 2 to 5, in which the rear panel (62) comprises an insert (58) overmolded with foam (60; 76).

7. A vehicle seat backrest according to claim 1, wherein the rear trim element (48) is a web (88), preferably attached to the backrest frame (17).

8. A vehicle seat back according to any preceding claim, wherein each side cover (37, 39) is sewn to the rear trim element (48), in particular to the rear panel (62) or the veil (88), if applicable.

9. Vehicle seat backrest according to one of the preceding claims, in which each side cover (37, 39) is fixed to fixing reliefs (66) of the rear trim element (48), in particular of the insert (58) of the rear panel (62) if applicable.

10. A vehicle seat backrest according to any preceding claim, wherein each side cover (37, 39) is attached to attachment reliefs of the backrest frame (17).

11. Vehicle seat backrest according to any one of the preceding claims in combination with claim 2, wherein the rear panel (62), in particular the insert (58) if applicable, comprises reliefs (64) for attachment to the backrest frame (17), in particular elastic fitting reliefs.

12. A vehicle seat backrest according to any preceding claim, wherein each side foam block (42, 44) is held in position around a respective upright (17b 172) of the backrest frame (17) by means of the respective side cover (37, 39), preferably only by means of the respective side cover (37, 39).

13. A vehicle seat backrest according to any preceding claim, wherein each lateral foam block (42, 44) is folded to at least partially cover three separate faces of the associated upright (17i, 172) of the backrest frame (17), in particular one face of the upright (17i, 172) facing the front of the vehicle seat (10), one face of the upright (17i, 172) facing the other upright (172, 17J, and one face of the upright (17i, 172) facing in the direction opposite to the other upright (172, 17J.

14. A vehicle seat backrest according to any preceding claim, further comprising at least one central upholstery module (40), disposed between the two side cushions (36, 38), the central upholstery module (40) preferably being adapted to be fixed to the backrest frame (17) independently of the side cushions (36, 38), the central upholstery module (40) preferably being fixed to the backrest frame (17) independently of the side cushions (36, 38).

15. A vehicle seat back according to claim 14, wherein the central upholstery module (40) comprises upholstery independent of the side cushions (36, 38).

16. A vehicle seat backrest according to claim 14 or 15, in wherein the central upholstery module (40) comprises at least one support (54), fixed to the backrest frame (17), and a central foam block (46) covering all or part of the support (54).

17. A vehicle seat backrest according to any preceding claim, wherein at least one side cushion (36, 38) comprises a side airbag device (70), attached to a post (17b 172) of the backrest frame (17) and at least partially surrounded by the foam block (42, 44) of said side cushion (36, 38).

18. Motor vehicle seat (10) comprising a seat (14) with a seat frame (15) and a backrest (16) according to any one of the preceding claims, the backrest frame (17) being fixed to the seat frame (15), preferably so as to be able to pivot about a transverse axis.

19. A method of manufacturing a backrest (16) of a motor vehicle seat (10) according to any one of claims 1 to 17, comprising the steps of: i) providing a backrest frame (17); ii) providing an integral subassembly (56), consisting of a rear trim element (48) and two side covers (37, 39) of side cushions (36, 38); iii) fixing the rear trim element (48) to the backrest frame (17); iv) filling each side cover (37, 39) with at least one block of foam (42, 44) at least partially surrounding an upright (17b 172) of the backrest frame (17) to form two side cushions (36, 38), step iv) preferably being carried out after step iii).

20. A method according to claim 19, wherein step ii) comprises the substeps of: a) providing a rear trim element (48); b) providing two side covers (37, 39); c) securing the two side covers (37, 39) to the rear trim element (48).

21. A method according to claim 20, wherein step a) comprises the substeps of: - forming an outer layer (72) by applying at least one layer of paint against a first forming surface (80) of a forming tool (78); - applying a skin (74), preferably made of water-free synthetic material, in particular water-free polyurethane, against an inner surface of the outer layer (72); and - applying a foam layer (76) against an inner surface of the skin (74), the foam layer (76) having a formulation containing water and a foaming catalyst at the time of its application to the skin (74).

22. The method of claim 21, wherein the skin (74) is substantially non-cellular polyurethane.

23. A method according to claim 21 or 22, wherein the foam layer is a cellular polyurethane foam.

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