METHOD FOR MANUFACTURED UPHOLSTERY FOR A MOTOR VEHICLE SEAT

Abstract

A method (100) for manufacturing padding (10), particularly for a motor vehicle seat, the method (100) comprising: / A / providing padding (10) comprising a 3D entanglement of continuous thermoplastic fibers (11), arranged irregularly, for example randomly, forming loops heat-sealed together, and / B / cutting said padding (10) using an ultrasonic cutting device (20) so as to delimit, at least partially, a predetermined peripheral contour (13) of the padding (10) or so as to form one or more internal openings (12) in the padding (10). Abstract figure: Figure 5

Description

Title of the invention: METHOD OF MANUFACTURING PADDING FOR A MOTOR VEHICLE SEAT technical field

[0001] This disclosure relates to a method for manufacturing padding, in particular for a motor vehicle seat. The disclosure also relates to padding obtained by said method and a seat comprising padding obtained by said method. Prior art

[0002] Seat padding is generally made largely of urethane polymer foam (or polyurethane, "PU"), in particular polyurethane foam obtained from polyether / polyol type polyols (or "PUR"). It is relatively easy to shape such foams in molds to obtain different shapes of padding for different vehicle seat components, such as the seat and backrest, for example. It is also known that fastening elements, such as pins, are inserted into the mold and overmolded. These fastening elements can be used to attach a soft cover to the padding by clipping it onto the fastening elements.

[0003] Polyurethane foam padding is satisfactory, but can retain moisture, particularly in humid or wet environments. This can lead to discomfort for an occupant of a vehicle seat equipped with a component containing such padding.

[0004] Furthermore, polyurethane foam is generally produced by mixing polyols with isocyanates, among other things. However, the chemical reaction involved in the formation of the foam emits CO2, which contributes to global warming. Moreover, polyurethane foam is not recyclable. Therefore, at the end of their life cycle, the seats are dismantled and sorted to separate the recyclable components from those that are not. The recyclable elements are then ground up to form a new raw material, while the non-recyclable elements are generally sent to landfill or, if possible, incinerated to produce energy.

[0005] The prior art, and in particular application FR 3 139 025-A1, describes a breathable padding made from a 3D entanglement of continuous thermoplastic fibers, arranged irregularly, forming loops heat-welded together, the manufacture of which requires less CO2.

[0006] Such padding consisting of a 3D entanglement of continuous thermoplastic fibers is formed by a thermoforming process and initially has a rough shape which must be reworked more precisely to obtain the desired dimensions.

[0007] A band saw can be used to trim padding made of a 3D entanglement of continuous thermoplastic fibers. However, a band saw only allows cutting in a straight line and does not allow cutting along a closed contour in the padding to create an internal opening. Summary

[0008] A method for manufacturing padding, particularly for a motor vehicle seat, is proposed, the method consisting of: - / A / provide padding that comprises a 3D entanglement of continuous thermoplastic fibers, arranged irregularly, for example randomly, forming loops heat-sealed together, and - / B / cut said padding using an ultrasonic cutting device so as to delimit, at least in part, a predetermined peripheral contour of the padding or so as to form one or more internal openings in the padding.

[0009] Step / B / may consist of cutting out said padding: - along one or more internal cutting lines on the padding, each internal cutting line forming a respective closed contour so as to form one or more internal openings in the padding, and / or - along one or more external cutting lines on the padding, each external cutting line following at least part of the peripheral contour of the padding.

[0010] The ultrasonic cutting apparatus may include an ultrasonic vibrating sonotrode comprising at least one cutting edge. During the cutting step / B / , the cutting edge of the sonotrode is moved over the padding along the internal cutting line(s) and / or along the external cutting line(s) while vibrations are applied to the sonotrode, preferably in a range between 20 kHz and 70 kHz, preferably between 20 kHz and 40 kHz.

[0011] The cutting edge of the sonotrode can extend lengthwise in a straight line or extend in a curved manner, preferably in a closed curved manner.

[0012] The ultrasonic cutting device may include a multi-articulated robotic arm that defines at least six axes of rotation and is designed to move and / or orient the cutting edge of the sonotrode along six degrees of freedom. The cutting edge of the sonotrode may be moved along a cutting line on the padding by the multi-articulated robotic arm during the cutting step / B / .

[0013] The ultrasonic cutting device may include a sonotrode and a support having a cutting edge. The cutting step / B / may consist of pressing the padding made of the 3D entanglement of continuous thermoplastic fibers between the sonotrode and the cutting edge while vibrations are applied to the sonotrode, preferably in a range between 20 kHz and 70 kHz, preferably between 20 kHz and 40 kHz.

[0014] The cutting step / B / can be carried out in a stiffened non-densified area of ​​the 3D entanglement of continuous thermoplastic fibers.

[0015] The 3D entanglement of continuous thermoplastic fibers can be in a solidified state during the cutting step.

[0016] The supply step / A / may consist of: - / Al / extrude a thermoplastic polymer through an extrusion die comprising extrusion nozzles distributed lengthwise and widthwise along the die, so as to generate a continuous curtain of molten fibers falling by gravity, - / A2 / receive the curtain of continuous molten fibers falling under the effect of gravity onto one or more support elements, in particular between two counter-rotating guide elements so as to generate a continuous layer of a 3D tangle of continuous thermoplastic fibers according to an irregular random distribution, with loops fusing between the continuous fibers, in particular according to a layer whose thickness is determined by the center distance between the two counter-rotating elements, - / A3 / solidify the 3D tangle layer of continuous thermoplastic fibers, for example by immersion in a coolant.

[0017] According to another aspect, padding is proposed, in particular for a motor vehicle seat, which can be obtained by the process described above.

[0018] According to another aspect, a seat for a motor vehicle is proposed, the seat comprising padding as described above and a cover over the padding. The cover can be attached to the padding by one or more fastening elements, in particular one or more elastic fastening elements. Brief description of the drawings

[0019] Other features, details and advantages will appear in the detailed description that follows and in the figures, where:

[0020] [Fig. 1] is a functional diagram illustrating a method for manufacturing padding for a motor vehicle seat according to the description.

[0021] [Fig.2] is a functional diagram of a step / A / of the process of [Fig.1].

[0022] [Fig.3] is a schematic view of an installation suitable for providing padding.

[0023] [Fig. 4] includes figures 4a and 4b which represent padding before and after a cutting step of the process of the [Fig.l].

[0024] [Fig.5] illustrates a cutting step of the process of [Fig.1].

[0025] [Fig. 6] includes figures 6a to 6c, each of which represents an embodiment of an ultrasonic sonotrode used in a cutting step of the process of [Fig.1].

[0026] [Fig.7] schematically represents an ultrasonic device used in a step of cutting of the process of the [Fig.l]. Description of the implementation methods

[0027] A method 100 for manufacturing padding 10, in particular for a motor vehicle seat, will now be described with reference to [Fig.1].

[0028] Method 100 consists of: - / A / provide padding 10 comprising a 3D entanglement of continuous thermoplastic fibers 11, arranged irregularly, for example randomly, forming loops heat-sealed together, and - / B / cut said padding 10 using an ultrasonic cutting device 20 so as to delimit, at least in part, a predetermined peripheral contour 13 of the padding 10 or so as to form one or more internal openings 12 in the padding 10.

[0029] Unlike other cutting technologies, ultrasonic cutting eliminates product waste and increases productivity and accuracy. In other words, step / B / consists of cutting or trimming the supply so that it meets the required dimensional specification. In particular, the padding 10 supplied in step / A / may have a rough shape. Step / B / may be part of a finishing process by cutting the padding 10 supplied in step / A / , which is necessary to assemble the padding 10 into a motor vehicle seat.

[0030] As shown in [Fig. 4], the delimitation, at least in part, of the peripheral contour 13 of the padding 10 can consist of removing excess material and creating a clean edge, in particular free of burrs, thus leaving the padding 10 ready to be finished or installed. "Delimiting" the peripheral contour 13 can be understood as "clearing" the peripheral contour 13 of the padding 10.

[0031] Internal openings 12 can be formed in the padding 10 to insert, respectively, rods and sleeves for a headrest, a hinge mechanism, an armrest hinge pin, tubes for a pneumatic function, or also fastening elements designed to secure a cover around the padding 10, as shown in [Fig. 4]. The internal openings 12 in the padding 10 can have any shape and, in particular, a shape circular or slot-shaped. One or more of the internal openings 12 may extend partially or completely through the padding 10. In other words, one or more of the internal openings 12 may be through holes.

[0032] As shown in Figures 2 and 3, the supply step / A / may include a step / Al / which consists of extruding a thermoplastic polymer in an extrusion die 31 comprising extrusion nozzles distributed in the length direction and in the width direction of the extrusion die 31, so as to generate a curtain 32 of continuous molten fibers, falling by gravity.

[0033] The extrusion temperature of step / Al / in the extrusion die 31 can be, for example, between 180 °C and 240 °C. The extrusion die 31 can be fed with thermoplastic polymer granules, for example, from a recycling process. Therefore, the fibers can also comprise a thermoplastic polymer. The fiber composition can comprise at least 95% by weight of PET or a polyester.

[0034] The fibers may be hollow and / or solid. The fibers may have a diameter between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm. In the expression "continuous fibers," the term "continuous" indicates that the fibers have a length much greater than their diameter, by, for example, a ratio of at least 100, or even 500, or even 1000.

[0035] The extrusion nozzles can be evenly distributed along the length of the extrusion die 31 and / or across its width. In other words, the density of the number of extrusion nozzles is homogeneous along the length of the extrusion die 31. Consequently, the apparent density can be homogeneous along the length and width of the layer 34.

[0036] The supply step / A / may also include a step / Al / which consists of receiving the curtain 32 of continuous molten fibers falling under the effect of gravity onto one or more support elements, in particular between two counter-rotating guide elements 32 so as to generate a continuous layer 34 of a 3D entanglement of continuous thermoplastic fibers 11 according to an irregular random distribution, with loops fusing between the continuous fibers, in particular according to a layer 34 whose thickness is determined by the center distance between the two counter-rotating elements.

[0037] The counter-rotating guide elements 32 can be driven in rotation at a speed that is generally lower than the falling speed of the fibers, which ensures that the fibers accumulate and form loops that heat-weld each other, thus generating an irregular and random three-dimensional entanglement.

[0038] The supply step / A / may include a step / A3 / which consists of solidifying the 3D entanglement layer 34 of continuous thermoplastic fibers 11, for example by immersion in a coolant 33.

[0039] The two guide elements can be immersed in the coolant 33, preferably halfway up.

[0040] The 3D entanglement layer 34 of continuous thermoplastic fibers 11, in continuous scrolling, can then be guided out of the coolant reservoir 33 to be dried, for example, by shaking / vibrating.

[0041] The supply step / A / may include a step / A4 / consisting of cutting the layer 34 in continuous scrolling, by means of a transverse cut, which makes it possible to obtain at least one padding 10 comprising the 3D entanglement of continuous thermoplastic fibers 11. Preferably, it is possible to obtain one or more paddings 10 by means of several transverse cuts of the layer 34 in continuous scrolling of the 3D entanglement of continuous thermoplastic fibers 11.

[0042] The supply step / A / may include a step / A5 / consisting of preforming the padding 10 comprising the 3D entanglement of continuous thermoplastic fibers 11, preferably by hot pressing or thermoforming. The padding 10 may be preformed according to its end use. The padding 10 may be, but is not limited to, seat padding 10, in particular seat cushion 10, backrest padding 10, armrest padding 10, or any other seat padding 10. The padding 10 supplied in step / A / may include a central portion, designed to receive a seat occupant, and two lateral portions, inclined relative to the central portion and designed to provide lateral support to the occupant.

[0043] In particular, it is possible to form localized densified and / or rigidified areas. For example, the padding 10 can be pre-formed to include at least one groove 14 on a face intended to receive the seat occupant. Each groove 14 can separate the central part from one of the lateral parts described above.

[0044] The 3D interlocking of continuous thermoplastic fibers 11 can have an apparent density between 20 kg / m³ and 70 kg / m³, in particular between 45 kg / m³ and 65 kg / m³, preferably between 35 kg / m³ and 55 kg / m³, and this in a substantially homogeneous manner. The density of such padding 10 is configured to ensure the comfort and support of the occupant.

[0045] One or more fibers of the 3D entanglement of continuous thermoplastic fibers 11 can extend over the entire length and / or width of the padding 10. In other words, the fibers can extend from a first end at a first edge of the padding 10 to a second end at a second edge of padding 10, the first and second ends being opposite in length or width.

[0046] The voids between the fibers of the 3D entanglement of continuous thermoplastic fibers 11 of the padding 10 can be left free. A highly breathable padding 10 is thus obtained, thanks to the numerous interstices between the fibers which promote air circulation, unlike a molded polyurethane body 22, which is comparatively close to an air-impermeable body 22.

[0047] It should be understood that the pre-formed padding 10 may still have a rough contour, thus requiring contour finishing as explained below with reference to step / B / .

[0048] Step / B / may consist of cutting said padding 110: - along one or more internal cutting lines on the padding 10, each internal cutting line forming a respective closed contour so as to form one or more of said internal openings 12 in the padding 10, and / or - along one or more external cutting lines on the padding 10, each external cutting line following at least a part of the peripheral contour 13 or a part of a peripheral edge of the padding 10.

[0049] The 3D entanglement of continuous thermoplastic fibers 11 can be in a solidified state during the cutting step. Surprisingly, it has been observed that cutting is easier and more precise when the 3D entanglement of continuous thermoplastic fibers 11 is in a solidified state. This also means that the process 100 does not require cutting the 3D entanglement of continuous thermoplastic fibers 11 in a viscous state, which can be difficult to maintain. In other words, step / A / can consist of providing a padding 10 comprising a 3D entanglement of continuous thermoplastic fibers 11 in a solidified state (as described above with reference to step / A3 / ).

[0050] The cutting step / B / can be carried out in a stiffened, undensified area of ​​the 3D entanglement of continuous thermoplastic fibers 11. In other words, the padding can be cut while maintaining the density described above. Thus, the cutting step / B / can be carried out without compressing the padding 10, particularly along a cutting line. According to one embodiment, it is possible to perform the cutting in a densified area of ​​the 3D entanglement of continuous thermoplastic fibers 11.

[0051] The ultrasonic cutting apparatus 20 may include an ultrasonic vibrating sonotrode 21 comprising at least one cutting edge 23. Vibrations may also be applied to the sonotrode 21 during the cutting step / B / , preferably in a range between 20 kHz and 70 kHz, preferably between 20 kHz and 40 kHz. The vibration of the cutting edge 23 helps to prevent snagging and the Sealing the 3D entanglement of continuous thermoplastic fibers 11 on the cutting edge 23 ensures optimal and reproducible cutting quality. Cutting step / B / may consist of moving the cutting edge 23 of the sonotrode 21 along the padding 10 along the internal cutting line(s) and / or along the external cutting line(s).

[0052] The cutting edge 23 can have a thickness between 0.01 mm and 5 mm.

[0053] The cutting edge 23 of the sonotrode 21 can extend lengthwise, in straight line, as shown in Figures 6a and 6b. The length of the cutting edge 23 may be less than 500 mm to ensure proper vibration of the cutting edge 23 and thus proper cutting. The sonotrode 21 may include a body 22. The cutting edge 23 may be formed at one end of the body 22 (Figure 6b). The body 22 may extend in a transverse direction, preferably perpendicular, to the direction along which the cutting edge 23 extends. In one embodiment, the cutting edge 23 may be formed along the sides of the body 22 (Figure 6a). The body 22 may have a sharp end. The cutting edge 23 of the sonotrode 21 may include multiple parts extending lengthwise in a straight line. The multiple parts of the cutting edge 23 can extend along respective directions that intersect each other. The multiple parts of the cutting edge 23 can be coplanar.

[0054] According to one embodiment, as shown in Figures 5 and 6c, the cutting edge 23 of the sonotrode 21 can extend in a curved manner, and preferably in a closed curved manner. Such a sonotrode 21 is particularly suitable for forming an internal opening 12 in the padding 10. More specifically, the cutting edge 23 of the sonotrode 21 can have a circular shape. The sonotrode 21 can also include a tubular body 22. The tubular body 22 of the sonotrode 21 can include at one end an opening that defines a passage inside the body 22 and that is delimited by the cutting edge 23. According to this embodiment, the cutting edge 23 can extend in a closed curved manner.The cutting step / B / may consist of lowering the sonotrode 21 onto the padding 10 (see arrow F1) to cut a hole in the padding 10 and remove a volume V of the 3D tangle of continuous thermoplastic fibers 11 (see arrow F2), for example, comparable to a cylindrical sample core. The tubular sonotrode 21 may be designed to maintain the volume of the 3D tangle of continuous thermoplastic fibers 11 after its removal from the padding 10 by cutting. The internal opening 12 may be coaxial with the tubular body 22 of the sonotrode 21. Remarkably, the removal of the volume of the 3D tangle of continuous thermoplastic fibers 11 may be carried out on the same side of the sonotrode 21 relative to the padding. This may... proves particularly useful if the internal opening 12 does not extend completely through the padding 10.

[0055] The sonotrode 21 may comprise several bodies each comprising at least one cutting edge 23 such as that described above, the bodies being structurally separated from each other.

[0056] With reference to [Fig. 7], the ultrasonic cutting apparatus 20 may include a multi-jointed robotic arm 24 defining at least six axes of rotation AR. The multi-jointed robotic arm 24 may be designed to move and / or orient the cutting edge 23 of the sonotrode 21 along six degrees of freedom. To this end, the sonotrode 21 (in particular the body 22) may be mounted at a free end of the multi-jointed robotic arm 24. The cutting edge 23 of the sonotrode 21 may be moved along a cutting line on the padding 10 by the multi-jointed robotic arm 24 during the cutting step / B / .

[0057] A logic processing unit may be provided and may include a control module comprising a microprocessor and memory containing instructions for, in step / B / , controlling the multi-articulated robotic arm 24 so as to move the cutting edge 23 of the sonotrode 21 along the cutting line. The cutting line on the padding 10 may be stored in the memory. More specifically, several cutting lines may be stored in the memory and one of them may be selected for step / B / , depending on the cut to be made and the type of cutting edge 23 used.

[0058] According to one embodiment, the sonotrode 21 can be mounted on a manual device. Therefore, the cutting step / B / can be carried out by manually moving the sonotrode 21 along a cutting line on the padding 10.

[0059] According to an alternative embodiment, the ultrasonic cutting device 20 may include a sonotrode and a support having a cutting edge. The cutting step / B / may consist of pressing the 3D entanglement of continuous thermoplastic fibers 11 between the sonotrode and the cutting edge while vibrations are applied to the sonotrode, preferably in a range between 20 kHz and 70 kHz, and more preferably between 20 kHz and 40 kHz. A preferred vibration frequency may be 30 kHz. In other words, the sonotrode and the cutting edge of the support are brought relative to each other to come to either side of the padding 10 in order to perform the cutting. In one embodiment, the sonotrode may be moved towards the support, while the latter may remain fixed or static.The sonotrode may have a face, preferably flat, which is brought into contact with one side of the padding 10 to press it onto the cutting edge of the support.

[0060] The ultrasonic cutting apparatus 20 may include an ultrasonic generator 25 and a converter 26 (visible in [Fig. 5]) which is coupled to said generator and which generates ultrasonic vibrations from the sonotrode 21. Optionally, the ultrasonic cutting device 20 may also include an electrical amplifier.

[0061] The process 100 may include a step / C / in which a cover is placed over the padding 10 and attached to the padding 10 by means of one or more fasteners. The material of the padding 10 and the material of said cover and fasteners may be the same material, or two different materials, but having similar physicochemical properties, in particular the same chemical composition. Advantageously, this allows the padding 10, the cover, and the fastener to be recycled simultaneously without being separated.

Claims

Demands

1. A method (100) for manufacturing padding (10), in particular for a motor vehicle seat, the method (100) consisting of: - / A / providing padding (10) which comprises a 3D entanglement of continuous thermoplastic fibers (11), arranged irregularly, for example randomly, forming loops that are heat-welded together, and - / B / cutting said padding (10) using an ultrasonic cutting device (20) so as to delimit, at least in part, a predetermined peripheral contour (13) of the padding (10) or so as to form one or more internal openings (12) in the padding (10).

2. A method (100) according to the preceding claim, wherein step / B / consists of cutting said padding (110): - along one or more internal cutting lines on the padding (10), each internal cutting line forming a respective closed contour so as to form one of said one or more internal openings (12) in the padding (10), and / or - along one or more external cutting lines on the padding (10), each external cutting line following at least a part of the peripheral contour (13) of the padding (10).

3. A method (100) according to the preceding claim, wherein the ultrasonic cutting apparatus (20) comprises an ultrasonic vibrating sonotrode (21) comprising at least one cutting edge (23), and wherein during the cutting step / B / the cutting edge (23) of the sonotrode (21) is moved on the padding (10) along the internal cutting line(s) and / or along the external cutting line(s) while vibrations are applied to the sonotrode (21), preferably in a range between 20 kHz and 70 kHz, preferably between 20 kHz and 40 kHz.

4. Method (100) according to the preceding claim, wherein the cutting edge (23) of the sonotrode (21) extends lengthwise in a straight line or extends in a curved manner, preferably in a closed curved manner.

5. A method (100) according to claim 3 or 4, wherein the ultrasonic cutting apparatus (20) comprises a multi-articulated robotic arm (24) that defines at least six axes of rotation (AR) and that is designed to move and / or orient the cutting edge (23) of the sonotrode (21) according to six degrees of freedom, the cutting edge (23) of the sonotrode (21) being moved along a cutting line on the padding (10) by the multi-articulated robotic arm (24) during the cutting step / R /

6. D / . Method (100) according to any one of claims 1 and 2, wherein the ultrasonic cutting apparatus (20) comprises a sonotrode (21) and a support having a cutting edge (23), and wherein the cutting step / B / consists of pressing the padding (10) made up of the 3D entanglement of continuous thermoplastic fibers (11) between the sonotrode (21) and the cutting edge (23) while vibrations are applied to the sonotrode (21), preferably in a range between 20 kHz and 70 kHz, preferably between 20 kHz and 40 kHz.

7. A method (100) according to any one of the preceding claims, wherein the cutting step / B / is carried out in a stiffened, non-densified area of ​​the 3D entanglement of continuous thermoplastic fibers (11).

8. A method (100) according to any one of the preceding claims, wherein the 3D entanglement of continuous thermoplastic fibers (11) is in a solidified state during the cutting step.

9. A method (100) according to any one of the preceding claims, wherein the supply step / A / consists of: - / A1 / extruding a thermoplastic polymer in an extrusion die (31) comprising extrusion nozzles distributed along the length and width of the extrusion die (31), so as to generate a curtain (32) of continuous molten fibers, falling by gravity, - / A2 / receiving the curtain (32) of continuous molten fibers falling under the effect of gravity onto one or more support elements, in particular between two counter-rotating guide elements (32) so as to generate a continuous layer (34) of a 3D entanglement of continuous thermoplastic fibers (11) in an irregular random distribution, with loops fusing between the continuous fibers, in particular in a layer (34) whose thickness is determined by the center distance between the two counter-rotating elements,

10. - / A3 / solidify the 3D tangle layer (34) of continuous thermoplastic fibers (11), for example by immersion in a coolant (33). Padding (10), in particular for a motor vehicle seat, which can be obtained by the process (100) according to any one of the preceding claims.

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