Vehicle seat component, in particular vehicle seat backrest, and manufacturing process thereof

Abstract

The present invention relates to a vehicle seat component (13; 16; 34) comprising a frame (14; 17; 35) and padding (15; 18; 36) attached to the frame (14; 17; 35). The padding (15; 18; 36) includes a cushion. The cushion comprises a mat (56) made of an interlocking of thermoplastic fibers forming loops welded together, the fibers being made of a polymer-containing material. The mat (56) comprises a first portion (56a) extending over a first face (17A) of the frame (17), and a first and second tab (561; 562) extending over a second face (17B) of the frame (17). An overlapping portion of the first tongue (561) overlaps an overlapping portion of the second tongue (562) on the second face (17B) of the frame (17). The overlapping portion of the first tongue (561) and the overlapping portion of the second tongue (562) are fixed together. Figure for the abbreviation: [Fig. 10]

Description

Title of the invention: Vehicle seat component, in particular vehicle seat backrest, and method for manufacturing it. Technical field

[0001] This disclosure relates to a vehicle seat component for a vehicle, in particular an automobile, and a method for manufacturing it. The vehicle seat component may, in particular, be a seat back. Previous art

[0002] A vehicle seat component, particularly a backrest or seat cushion, generally comprises a frame and upholstery attached to the frame. The upholstery includes at least one layer of padding, which can be attached to a support part. The padding generally comprises one or more blocks of urethane (or polyurethane, PU) polymer foam, particularly polyurethane foam obtained from polyester / polyol (or PUR) type polyols. Such blocks can be produced and shaped in molds. These urethane polymer foam blocks can even be overmolded onto the frame or the support part for the padding. Thus, these foam blocks can easily be adapted to different shapes of a vehicle seat component. Furthermore, these blocks can easily be attached to the vehicle seat component.

[0003] Polyurethane foam padding is satisfactory, but can retain moisture, particularly in humid conditions. This can cause discomfort for an occupant of a vehicle seat, one element of which includes such padding.

[0004] Furthermore, polyurethane foam is conventionally manufactured by mixing, among other things, polyols with isocyanates. The chemical reaction carried out emits CO2 to form a foam. The CO2 emitted contributes to global warming.

[0005] In addition, polyurethane foam is not recyclable.

[0006] Thus, it appears desirable to limit the use of polyurethane in the padding of the trim elements of a vehicle.

[0007] French patent application FR-A-3139025 describes a padding for a vehicle seat component, formed from a 3D entanglement of continuous fibers, irregularly arranged and forming loops welded together. This padding is breathable and requires less CO2 to manufacture. However, this entanglement of continuous fibers cannot be fixed in a vehicle seat component using the same fastening system as those used for padding made of polyurethane foam. Summary

[0008] In this disclosure, a vehicle seat component is described, in particular a vehicle seat backrest, comprising a frame and upholstery attached directly or indirectly to the frame, the upholstery comprising padding, the padding preferably comprising a mat of an entanglement of thermoplastic fibers forming loops welded together, the fibers being made of a material comprising a polymer, the mat comprising at least a first portion extending over a first face of the frame, intended to be oriented towards an occupant of the vehicle seat, and a first and second tab extending at least partially over a second face of the frame, opposite the first face of the frame,in which at least one overlapping portion of the first tongue overlaps at least one overlapping portion of the second tongue on the second face of the frame, and in which the overlapping portion of the first tongue and the overlapping portion of the second tongue are fixed together.

[0009] Optionally, the vehicle seat element may include one or more of the following features, taken alone or in combination: - the overlapping part of the first tab and the overlapping part of the second tab are fixed together by ultrasonic welding; - the overlapping part of the first tongue and the overlapped part of the second tongue are fixed together along a fixing part, said fixing part comprising separate strips, preferably having enlarged ends; - the overlapping part of the first tongue and the overlapped part of the second tongue are fixed together along a fixing part, the fixing part being flush with the first and second tongues, outside the overlapping part of the first tongue and the overlapped part of the second tongue, on its face oriented opposite to the reinforcement; - the padding includes a quilting support fixed to the frame, the carpet being fixed around at least one end of the quilting support; - the padding support includes a part extending over the first face of the frame and a part extending over the second face of the frame; - the padding support extends in a U-shape around one end of the frame; and - The vehicle seat element is one of the following: — a vehicle seat back; — a vehicle seat base; — a headrest of a vehicle seat; — an armrest.

[0010] According to another aspect, a method for manufacturing a vehicle seat component according to any one of the preceding claims is described, comprising the steps of: - provide the frame for the vehicle seat element and the carpet for the trim; - fold the carpet of the upholstery so that at least a first part extends over a first face of the frame, intended to be oriented towards an occupant of the vehicle seat, and that a first and a second tab extend at least partially over a second face of the frame, opposite the first face of the frame, in which at least an overlapping part of the first tab overlaps at least an overlapped part of the second tab on the second face of the frame; and - fix together at least one overlapping part of the first tab with at least one overlapping part of the second tab.

[0011] The overlapping part of the first tab and the overlapping part of the second tab can be fixed together by ultrasonic welding. Brief description of the drawings

[0012] The detailed description refers in particular to the attached figures in which:

[0013] [Fig-1] schematically shows an example of a vehicle seat, seen in cross-section;

[0014] [Fig.2] is a flowchart of an example of a manufacturing process for the vehicle seat back of [Fig.1];

[0015] [Fig.3] schematically shows the backrest frame of the vehicle seat of [Fig.1];

[0016] [Fig.4] schematically illustrates a step in the process of [Fig.2];

[0017] [Fig.5] schematically illustrates the rear side of a padding support of the vehicle seat back of the [Fig.l];

[0018] [Fig.6] schematically illustrates a padding to be fixed on the padding support of [Fig.5];

[0019] [Fig.7] schematically shows part of the rear side of the padding support of [Fig.5] on which the padding of [Fig.6] is placed;

[0020] [Fig.8] schematically shows a cross-section of a detail of the padding of [Fig.6] placed on the padding support of [Fig.5];

[0021] [Fig.9] schematically illustrates a step of fixing the padding of [Fig.6] onto the padding support of [Fig.5] by ultrasonic welding;

[0022] [Fig. 10] schematically illustrates the padding of [Fig.6] fixed on the padding support of [Fig.5];

[0023] [Fig. 11] schematically illustrates a detail of [Fig. 10] in cross-section. Detailed description

[0024] In the various figures, the same reference numerals designate identical or similar elements. For the sake of brevity, only the elements that are useful for understanding the embodiment described are shown in the figures and described in detail below.

[0025] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "rear", "top", "bottom", "left", "right", etc., or to relative qualifiers, such as the terms "above", "below", "superior", "lower", etc., or to orientation qualifiers, such as "horizontal", "vertical", etc., unless otherwise indicated, these refer to the orientation of the figures or of a vehicle seat in its normal position of use.

[0026] In particular, the longitudinal direction X refers to 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 is 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.

[0027] Fig. 1 schematically shows a motor vehicle seat 10 mounted on a sliding mechanism 12.

[0028] The seat 10 comprises a seat 13 (or part of a seat), with a seat frame 14 and a seat cushion 15, on which is mounted a backrest 16, with a backrest frame 17 and a backrest cushion 18. Here, the backrest frame 17 pivots about an axis A, relative to the frame of the seat part 14. To do this, a hinge mechanism 20 is arranged between the frame of the seat part 14 and the backrest frame 17. The axis A is, for example, substantially parallel to the transverse direction Y.

[0029] The seat portion 13 is mounted on movable profiles 22, also called glides 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.

[0030] In this example, the seat 10 includes a manual control member 32, called a lever, for controlling the sliding of the slides 12. This manual control member 32 makes it possible, in particular, to lock and unlock the stop systems that prevent the sliding of the movable profiles 22 relative to the respective fixed profiles 28. Once the stop systems are released, the manual control member 32 can also be used to slide the movable profiles 22 relative to their respective fixed profiles 28 of the slide 12 along the longitudinal direction X of the slides 12. The fixed profiles 28 and movable profiles 22 of the slides 12 can be made of metal.

[0031] Alternatively, the movement of the movable profiles 22 relative to the fixed profiles 28 is controlled by means of an actuator. One or more actuator control buttons can then be arranged on the seat 10, in particular on the seating portion 13.

[0032] The seat 10 further includes a headrest 34. The headrest 34 comprises a headrest frame 35 and a headrest trim 36. The headrest frame 35 is connected to the backrest frame 17 by means of at least one headrest attachment rod 38, preferably two headrest attachment rods 38 received in sockets formed by the backrest frame 17. The headrest attachment rod(s) 38 may be of variable length to allow adjustment of the height of the headrest 34. In addition, or alternatively, the headrest frame 35 is movable relative to the headrest attachment rod(s) 38 to allow this adjustment of the height of the headrest 34. The headrest trim 36 and / or the backrest trim 18 may cover all or part of the headrest attachment rod(s) 38, for example to improve the aesthetics of the vehicle seat 10.

[0033] In what follows, the file 16 of the vehicle seat 10 and its manufacturing process 100 illustrated in [Fig.2] are described in more detail.

[0034] As illustrated in [Fig. 2], the method 100 comprises a first step 102 of supplying a backrest frame 17. As illustrated in [Fig. 3], the backrest frame 17 essentially comprises a first upright 17i, a second upright 172, a first crossbar 173, hereinafter referred to as the "lower crossbar 173", and a second crossbar 174, hereinafter referred to as the "upper crossbar 174". The uprights 17i, 172 and the crossbars 173, 174 form a backrest frame 17 in the form of a frame. To achieve this, the uprights 17i, 172 and the crossbars 173, 174 can be fastened together, in particular welded together. Alternatively, the backrest frame 17 is a single piece, for example, by being molded.

[0035] Here, the headrest attachment rods 38 are already fixed to the upper cross member 17 4 of the backrest frame 17 in this first step 102. Alternatively, however, these headrest attachment rods 38 can be attached to the upper cross member 17 4 of the backrest frame 17 in a later step.

[0036] During a second step 104 of the manufacturing process 100, a first lateral trim module 40 and a second lateral trim module 42 are fixed to the face front 17A of the backrest frame 17, visible in [Fig.3], on a respective upright 17i, 172 of the backrest frame 17. Thus, a lateral trim module 40, 42 is arranged on each side of the backrest frame 17. The front face 17A of the backrest frame 17 is the face of the backrest frame 17 intended to be oriented towards an occupant of the vehicle seat 10. The rear face 17B of the backrest frame 17 is the face opposite the front face 17A.

[0037] In the present case, the first and second trim modules 40, 42 form a support cushion on each side of the backrest 16.

[0038] Each side trim module 40, 42 here comprises a padding, each padding being fixed to a respective support 48, 50. Each support 48, 50 can be fixed to the respective upright 171, 172 of the backrest frame 17, in particular by snap-fitting and / or welding and / or screwing and / or riveting and / or forced insertion of a shaped relief into a complementary relief, in particular. Here, each support 48, 50 can comprise a respective upright with snap-fit ​​reliefs 52 allowing an airbag support, on which an airbag is fixed, to be fixed to the upright, here by snap-fitting. Each airbag is connected to a pump for inflation. Airbags thus improve lateral support for the occupant of the vehicle seat 10. In the illustrated example, each snap-in relief 52 is in the form of a U-shaped hook, into which a rod formed by the airbag support is snapped.Other forms of the 52 ratchet reliefs are accessible to those skilled in the art.

[0039] The first side trim module 40, intended to be positioned as centrally as possible in the motor vehicle equipped with the seat 10, may further include a side airbag safety device. Such an airbag device is designed to prevent direct head-to-head impacts between the occupants of two seats arranged transversely, one next to the other. The airbag system is at least partially covered by the padding of the first side trim module 40.

[0040] The manufacturing process 100 then continues with a step 106 of fixing a padding support 54 onto the backrest frame 17, on the front face 17A. Here, the padding support 54 is arranged between the two side trim modules 40, 42.

[0041] As illustrated in [Fig.4] and [Fig.5], the padding support 54 can be in the form of a plate.

[0042] The padding support 54 may include an upper part 54 b, a middle part 54 2, and a lower part 54 3.

[0043] The upper part 54 i can be shaped to facilitate the installation of the padding support 54 onto the backrest frame 17. To do this, the upper part 54 i of the The padding support 54 may have openings suitable for sockets fixed to the backrest frame 17 and adapted to receive the headrest attachment rod(s) 38. Thus, the upper part 54 i is placed above the upper crossbar 17 4, around the sockets. The padding support 54 thus covers the upper crossbar 17 4 of the backrest frame 17. To do this, the upper part 54 i of the central front padding support 54 can be curved so as to form a housing 60 receiving the upper crossbar 17 4 of the backrest frame 17 as well as an upper part of the first and second uprights 17 i, 17 2. The housing 60 is delimited by the front wall of the padding support 54, extending over the front face of the backrest frame 17, and a rearward curved edge 62 of the padding support 54, in particular its upper part 54 b extending essentially over the rear face 17B of the backrest frame 17.

[0044] The inner faces of the upper part 54 i of the padding support 54 and of the rearward curved edge 62, oriented towards the inside of the housing 60, may be provided with reliefs to guide the mounting of the padding support 54 on the backrest frame 17 and / or to participate in the fixing of the padding support 54 on the backrest frame 17. For example, the inner face of the upper part 54 i of the padding support 54 and of the rearward curved edge 62, oriented towards the inside of the housing 60, may be provided with snap-in reliefs adapted to cooperate with additional snap-in reliefs arranged on the backrest frame 17, in particular on the upper crossbar 17 4 and / or the uprights 17 i, 17 2.

[0045] The central portion 54 2 of the padding support 54 essentially serves to support a backrest padding 56, where the occupant of the vehicle seat 10 leans primarily against the seat back 16. The central portion 54 2 thus advantageously provides sufficient mechanical resistance to prevent the padding 56 from sinking completely when an occupant of the vehicle seat 10 leans against the seat back 16. However, the central portion 54 2 is advantageously still relatively flexible to ensure the comfort of the occupant of the vehicle seat 10. The deflection of the central portion 54 2 of the padding support 54 can be limited by ridges on the backrest frame 17 and / or on a rear shell fixed to the rear face of the backrest frame 17B.

[0046] Finally, the lower part 54 3 is formed here to ensure the attachment of the padding support 54, in this case on the backrest frame 17. Here, this lower part 54 3 is curved towards the rear and is provided with snap-in reliefs 64 suitable for engaging with complementary reliefs on the lower cross member 17 3 of the backrest frame 17 and / or on a rear shell fixed on the rear face of the backrest frame 17B.

[0047] The padding support 54, in particular its central portion 54 3, can support one or more components 55 for performing one or more comfort and / or safety functions for the occupant of the vehicle seat 10. For example, a fan can be attached to this central portion, suitable for blowing air towards the seat occupant. In other examples, a vibrator and / or pneumatic equipment for performing a massage function and / or heating equipment can be attached to the padding support 54.

[0048] The manufacturing process 100 then continues with a step 108 of supplying the backrest padding 56.

[0049] In the present case, the backrest padding 56 is composed of a mat of a mass (or entanglement) of fibers, said fibers forming loops that are heat-sealed together. The backrest padding 56 has the shape of a mat since its thickness is substantially constant over its entire surface. The thickness is the smallest dimension of the backrest padding 56. The thickness of the backrest padding 56 can be between 15 mm, preferably 50 mm, and 100 mm, preferably 60 mm. The thickness can be five times, preferably ten times, smaller than the other two dimensions of the backrest padding 56, which are its length and its width. Preferably, the thickness of the backrest padding 56 is measured in a direction that is substantially perpendicular to the padding support 54.

[0050] The fibers in the fiber bundle forming the backrest padding 56 can be described herein as "continuous" in the sense that their length is much greater than their diameter. For example, the ratio between the fiber length and their diameter can be at least 100, preferably 500, and more preferably 1000. Preferably, the fibers extend from a first end on a first edge of the bundle to a second end on a second edge of the bundle, opposite the first edge. Furthermore, the diameter of the fibers can be between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm. The fibers can be hollow and / or solid.

[0051] The fiber cluster can be described as "three-dimensional" because the thickness of the resulting fiber cluster is not negligible, in that it is preferably much greater than the diameter of the fibers. In particular, the thickness of the resulting fiber cluster is at least 10 times, preferably at least 30 times, and more preferably at least 50 times, greater than the diameter of the fibers in the fiber cluster.

[0052] The fibers comprise a thermoplastic polymer, the fiber composition preferably comprising at least 95% by weight of PET. For example, the fiber composition, or even the cushion composition, comprises: - 95% to 99% by weight of a first polymer from the polyester family such as PET (polyethylene terephthalate), - 1% to 5% by weight of a second polymer from the polyester family, such as PTT (polyethylene terephthalate) or PBT (polybutylene terephthalate). The sum of PET and PTT (or PBT) can be 100% by weight of fibers, or even of the backrest padding 56. The backrest padding 56 can have an apparent density between 20 kg / m3 and 70 kg / m3, or even between 45 kg / m3 and 65 kg / m3.

[0053] Preferably, the gaps between the fibers of the fiber cluster of the backrest padding 56 are left free. A highly breathable backrest padding 56 is obtained, due to the numerous gaps between the fibers which promote air circulation.

[0054] An example of a method for producing the backrest padding 56 is briefly described below.

[0055] The process, which can be continuous, comprises a first step of extruding a plastic material containing at least one thermoplastic polymer through an extrusion die comprising a plurality of extrusion nozzles. For this purpose, the extrusion die can be supplied with polymer granules. The extrusion die can, for example, be adapted to heat the plastic material, in particular the polymer granules, to a temperature between 180 °C and 240 °C. The extrusion nozzles can be evenly distributed in two perpendicular directions to form an extrusion nozzle matrix. The extrusion die thus forms a curtain of continuous, molten fibers, the fiber density of which is substantially constant in cross-section (i.e., in a plane perpendicular to the direction of advancement of the extruded fibers). The extrusion nozzles can be distributed in a horizontal plane.Similarly, to maintain a substantially constant fiber density in the cross-section of the fiber curtain, the fibers are driven by gravity at the exit of the extrusion die. The term "fiber curtain" here refers to a configuration of fibers extending substantially parallel to each other, the fibers being contained, in a plane perpendicular to their direction of travel, within an envelope curve corresponding substantially to the cross-section of the extrusion die, for example, substantially rectangular.

[0056] In a second step of the process, the molten fibers are drawn towards two counter-rotating guide elements. The guide elements may be identical rollers, in particular rollers of the same constant diameter. Preferably, the minimum distance between the two rollers is less than the smaller dimension (or width) of the cross-section of the fiber curtain, while the other dimension of the cross-section of the fiber curtain, the larger one (or length), is substantially equal to or less than the length of the rollers. Preferably, at the exit of the die Upstream of the extrusion die and rollers, the temperature of the plastic material from which the fibers are formed is greater than or equal to 150 °C, preferably greater than or equal to 160 °C, and / or less than or equal to 190 °C, preferably less than or equal to 180 °C. Preferably, both rollers rotate at the same speed. The speed of the two rollers is chosen to create a bottleneck of molten fibers upstream of the two rollers. This can be achieved, in particular, by choosing a roller speed such that the product of the smallest surface area between the two rollers and the roller rotation speed is less than the surface flow rate of the extrusion die. As a specific example, this can be achieved by choosing a roller rotation speed lower than the speed of the fiber curtain upstream of the two rollers.

[0057] Thus, an accumulation of molten fibers forms upstream of the rollers. The fibers then tend to form continuous loops, which, due to the fiber temperature, fuse together. In particular, the fibers can fuse with each other.

[0058] A mass of molten fibers can thus be obtained, which is then guided between the rollers to have a substantially rectangular cross-section. In particular, the thickness of the fiber mass can be defined by the distance between the two rollers, the thickness of the fiber mass being in particular substantially equal to the distance between the two rollers. The fibers can be distributed irregularly within the fiber entanglement, in particular according to a distribution that may appear random to an observer. The volume of fibers passing through the area between the two rollers can be substantially constant per unit of time. In other words, the fiber mass can be continuous at the exit of the rollers.

[0059] In a third step of the process, the fibers are solidified. To do this, the fiber tangle can be guided into a cooling bath, for example a coolant bath such as water, after passing through the passage between the two rollers. For example, the two rollers can be half-immersed.

[0060] In a fourth step of the process, the fiber bundle is guided out of the cooling bath, specifically to be dried. Drying can be carried out by agitating / vibrating the fiber bundle. The fiber bundle can then be shaped, specifically cut, to form the backrest padding 56 as illustrated in [Fig. 6].

[0061] The backrest padding 56 can be substantially homogeneous, having similar fibers and a homogeneous apparent density, in substantially the entire volume of the backrest padding 56.

[0062] As can be seen in [Fig. 6], the backrest padding 56 comprises a main part 56a designed to extend over the front face 54A of the padding support 54, here between the two supports on the backrest 16, and fastening tabs 56i, 562 designed to extend at least partially over the rear face of the backrest frame 17B. As illustrated, the backrest padding 56 comprises a central fastening tab 56i, and two lateral fastening tabs 562 extending on each side of the central fastening tab 56b as illustrated in [Fig. 6], i.e., before being fixed in the backrest 16.

[0063] The manufacturing process 100 then continues with a step 110 of fixing the backrest padding 56 onto the backrest frame 17.

[0064] To do this, the main part 56a of the backrest padding 56 is placed against the main part 542 of the padding support 54, on the front face 54A of the padding support 54. Then, the fastening tabs 56i, 562 are bent so as to extend at least partially towards the rear side of the backrest frame 17B, as illustrated in [Fig. 7]. As can be seen more clearly in [Fig. 8], the fastening tabs 56i, 562 overlap each other on the rear side of the backrest frame 17B. More specifically, the central fastening tab 56i here comprises two overlapping parts, each overlapping a corresponding overlapping part of a lateral fastening tab 562.

[0065] In the present case, the fixing tabs 56 i, 56 2 face the external face of the rearward curved edge 62 of the padding support 54, opposite the housing 60. According to another embodiment, the tabs 56 i, 56 2 could further face the internal face of the rearward curved edge 62 of the padding support 54, oriented towards the housing 60, the fixing tabs 56 i, 56 2 then being folded around the free end 62a of the rearward curved edge 62 of the padding support 54.

[0066] The fixing tabs 56 i, 56 2 then extend away from the rearward curved edge 62 of the padding support 54 or in contact with the rearward curved edge 62 of the padding support 54. In addition, in the present case, the fixing tabs 56 i, 56 2, when folded, together with the main part 56a of the back padding 56, form corners around the padding support 54.

[0067] The overlapping parts of the fixing tabs 56 i, 56 2 are then fixed together. As a result, the backrest padding 56 is fixed to the padding support 54, the corners formed by the fixing tabs 56 i, 56 2 and the main part 56a of the backrest padding 56 preventing movement of the backrest padding 56 relative to the padding support 54.

[0068] In the present case, the overlapping portion of the central fixing tab 56 i and the overlapping portion of a lateral fixing tab 56 2 are joined together by ultrasonic welding, as schematically illustrated in [Fig. 9]. An ultrasonic welding system 66 is used for this purpose. Ultrasonic welding is preferred because it does not involve any third-party parts or products for joining the fixing tabs 56 b and 56 2 together. Other advantages of ultrasonic welding include its speed, the fact that it can be easily automated, produces clean and precise joints, and leaves a very clean weld area.

[0069] As illustrated, the ultrasonic welding system 66 is composed of: - of an electronic ultrasound generator 68 delivering an electrical signal; - a converter 70, for example a piezoelectric transducer, to convert the electrical signal into a mechanical vibration using a piezoelectric effect; - an optional amplifier 72 to mechanically modify the amplitude of the vibration; and - of a sonotrode 74 (or horn) to mechanically modify the amplitude and apply the mechanical vibration to the fixing tabs 56 i, 56 2 to be welded.

[0070] The converter 70, the amplifier 72, if applicable, and the sonotrode 74 form a stack. They are specifically tuned to resonate at the same ultrasonic frequency, for example 20 kHz, 30 kHz or 40 kHz.

[0071] A press 76 and an anvil 78 can also be associated with the ultrasonic welding system 66 to hold the sonotrode 74 pressed against the upper tab among the fixing tabs 56b 562. The anvil 78 can also allow high-frequency vibrations to be directed towards the interface between the fixing tabs 56i, 562 to be fixed together.

[0072] Thanks to the ultrasonic welding system 66, in particular the sonotrode 74, high-frequency, low-amplitude ultrasonic acoustic vibrations are applied locally to the overlapping portion of the lateral retaining tab 562, which is clamped with the overlapping portion of the central retaining tab 56i between the press 76 and the anvil 78. The absorption of the ultrasonic acoustic vibrations causes local melting and mixing of the thermoplastic material of the retaining tabs 56i, 562 along a bond 80. In other words, the ultrasonic energy melts points of contact between the overlapping portion of the lateral retaining tabs 562 and the overlapping portion of the central retaining tab 56i, creating a bond 80 by local melting and / or mixing of the thermoplastic material of the retaining tabs 56i, 562. 2.

[0073] The linkage 80 between the fixing tabs 56 i, 56 2 can have different designs. The shape of the sonotrode 74, in particular, can influence the shape of the linkage between the fixing tabs 56 i, 56 2.

[0074] As can be seen in [Fig. 10], the link 80 may comprise several segments 82 (or strips) having enlarged ends 84. The segments 82 of the link 80 may be parallel. Such a form of the link 80 allows for effective fastening of the fastening tabs 56 i, 56 2 together while maintaining satisfactory flexibility of the backrest padding 56. Flexibility of the backrest padding is preferred for the comfort of the seat occupant as well as for an aesthetic installation of the backrest padding 56 on the padding support 54, particularly on its rearward curved edge 62.

[0075] As can be seen in [Fig. 11], the connection 80 is preferably flush with the fixing tabs 56 i, 56 2 on their outer surfaces 56 i °, 56 2 °. The outer surfaces 56 i °, 56 2 0 of the fixing tabs 56 i, 56 2 are free, unlike the inner surfaces 56 x 1; 56 21 opposite and, in the present case, in contact with the padding support 54. Since ultrasonic welding involves melting at least one of the fixing tabs 56 i, 56 2, a gap 83 may appear between the padding support 54 and the connection 80. It is preferred that this gap 83 does not appear on the free face of the padding 56, but rather on the face of the padding in contact with the padding support 54 and / or opposite the frame 17 of the backrest.

[0076] The attachment of the backrest padding 56 to the top of the padding support 54 is described above. The backrest padding 56 can be attached in the same way to the lower end of the padding support 54. In this case, the backrest padding 56 includes fixing tabs at its lower end, opposite its upper end from which the fixing tabs 56 i, 56 2 previously described extend.

[0077] The method 100 then includes a step 112 of attaching at least one cover to the padding 56. One cover can cover the entire backrest padding. Alternatively, several covers can cover separate parts of the backrest padding.

[0078] The invention is not limited solely to the examples described above. On the contrary, the invention may have many variations accessible to a person skilled in the art.

[0079] Thus, in the illustrated example, the front part of the backrest trim 18 comprised modules, in particular side modules 40, 42. Alternatively, however, the backrest trim 18, in particular its front part intended to be in contact with a The vehicle seat occupant 10 can be produced in another form, in particular as a single unit without separate modules. Specifically, the backrest trim 18 may not include any side modules 40, 42.

[0080] Furthermore, the description refers specifically to the attachment of padding to a backrest frame 17. However, a person skilled in the art understands that the teaching of this description applies to the attachment of padding to a frame of any vehicle seat element, such as a seat part, a headrest or an armrest.

Claims

Demands

1. A vehicle seat element (13; 16; 34), in particular a backrest (16) of a vehicle seat (10), comprises a frame (14; 17; 35) and upholstery (15; 18; 36) attached directly or indirectly to the frame (14; 17; 35), the upholstery (15; 18; 36) comprising padding, the padding comprising, preferably, a mat (56) of an entanglement of thermoplastic fibers forming loops welded together, the fibers being made of a material comprising a polymer, the mat (56) comprising at least a first portion (56a) extending over a first face (17A) of the frame (17), intended to be oriented towards an occupant of the vehicle seat (10), and a first and second tabs (56i;562) extending at least partially over a second face (17B) of the frame (17), opposite the first face (17A) of the frame (17), wherein at least one overlapping part of the first tongue (56i) overlaps at least one overlapped part of the second tongue (562) on the second face (17B) of the frame (17) and wherein the overlapping part of the first tongue (56i) and the overlapped part of the second tongue (562) are fixed together.;

2. Vehicle seat element according to claim 1, wherein the overlapping part of the first tongue (560) and the overlapping part of the second tongue (562) are fixed together by ultrasonic welding.

3. Vehicle seat element according to claim 1 or 2, wherein the overlapping portion of the first tongue (561) and the overlapped portion of the second tongue (562) are fixed together along a fastening portion (80), said fastening portion (80) comprising separate strips (82), preferably having enlarged ends (84).

4. A vehicle seat element according to any one of claims 1 to 3, wherein the overlapping portion of the first tongue (561) and the overlapping portion of the second tongue (562) are fixed together along a fastening portion (80), wherein the fastening portion (80) is flush with the first and second tongues (561, 562), outside the overlapping portion of the first tongue (561). i) and the overlapping part of the second tongue (562), on its face oriented opposite to the armature (17).

5. Vehicle seat element according to any one of claims 1 to 4, wherein the upholstery comprises a padding support (54) fixed to the frame (17), the carpet (56) being fixed around at least one end of the padding support (54).

6. Vehicle seat element according to claim 5, wherein the padding support (54) comprises a portion extending over the first face (17A) of the frame (17) and a portion (62) extending over the second face (17B) of the frame (17).

7. Vehicle seat element according to claim 6, wherein the padding support (54) extends in a U-shape around one end (174) of the frame (17).

8. Vehicle seat element according to any one of the preceding claims, wherein the vehicle seat element is one of: - a backrest (16) of a vehicle seat (10); - a seat (13) of a vehicle seat (10); - a headrest (34) of a vehicle seat (10); - an armrest.

9. Method of manufacturing a vehicle seat element (13; 16; 34) according to any one of the preceding claims, comprising the steps of: - providing the frame (14; 17; 35) of the vehicle seat element (13; 16; 34) and the carpet of the trim (56); - fold the carpet of the trim (56) so that at least a first part (56a) extends over a first face (17A) of the frame (17), intended to be oriented towards an occupant of the vehicle seat (10), and that a first and a second tab (56i; 562) extend at least partially over a second face (17B) of the frame (17), opposite the first face (17A) of the frame (17), in which at least an overlapping part of the first tab (561) overlaps at least an overlapped part of the second tab (562) on the second face (17B) of the frame (17);and - fix together at least one overlapping part of the first tab (560) with at least one overlapping part of the second tab (562).;

10. Method according to claim 9, wherein the overlapping part of the first tab (56i) and the overlapping part of the second tab (562) are fixed together by ultrasonic welding.

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