Vehicle seat cushion including an anti-submarining insert

Abstract

A vehicle seat assembly comprising a base frame (1), a seat frame (2), foam padding (3), and a cover (5), characterized in that it includes an anti-submarining insert (4), formed as a separate piece, mounted against a bearing area provided in the seat frame and covered by the foam padding, the foam padding itself being covered by the cover, and the choice of the anti-submarining insert is adapted according to the seat's position in the vehicle. Figure 1

Description

Title of the invention: Vehicle seat cushion comprising an anti-submarine insert

[0001] The present invention relates to motor vehicle seats. More specifically, it concerns vehicle seat cushions incorporating an anti-submarining function.

[0002] In motor vehicles, vehicle occupants must be properly restrained by the seat belt in the event of an accident. This restraint function requires preventing the occupant's pelvis from passing under the lap belt, and therefore the seat cushion must provide an anti-submarining function, which prevents the occupant's pelvis from sliding forward and passing under the lap belt.

[0003] However, the effectiveness of the anti-submarining function depends on the seat arrangement in the vehicle and, in particular, on the possible inclination of the seat relative to the horizontal. For example, in a utility vehicle, the seat frame is generally horizontal, whereas in a passenger vehicle, the seat frame is generally in a slightly upturned position.

[0004] It is known to achieve the anti-submarine function by means of a crossbar of the frame which is located under the thighs of the occupant.

[0005] However, care must be taken to ensure that the user's comfort is preserved and that the crossbar for the anti-submarining function does not present a permanent discomfort under the occupant's thighs.

[0006] There is also a tendency to use a combination of metal reinforcement and plastic frame to make a seat.

[0007] It is in this context that the inventors sought to propose a new solution that could combine modular seat manufacturing, user comfort from the occupant's point of view and the desired effectiveness of the anti-submarining function for different types of vehicles that could be equipped with the type of seat or family of seats in question.

[0008] For this purpose, a vehicle seat assembly is proposed comprising a basic frame (generally made of metal), a seat frame (generally made of plastic), a foam cushion, and a cover (generally made of fabric, or even leather), characterized in that it provides an anti-submarining insert, mounted in support on a support area provided in the seat frame and covered by the foam cushion, the foam cushion itself being covered by the cover.

[0009] It should be noted that the anti-submarine insert is a separate part from the seat frame.

[0010] Advantageously, the anti-submarine insert forms an ad hoc bump which provides the anti-submarine function.

[0011] Thanks to the provisions set out above, the anti-submarining insert can be chosen according to the application of the seat and particularly according to the inclination of the seat relative to the horizontal (here we are talking about the reference horizontal of the vehicle) in order to optimize the anti-submarining function according to the posture of the occupant.

[0012] The anti-submarine insert allows for the resumption of the forces induced by the inertial forces of a front impact and which are directed forward and downwards on the anti-submarine insert and on the support area provided in the seat frame.

[0013] It is noted that the anti-submarining insert forms a wedge working in compression under a forward crash. Different inserts can therefore be used depending on the seat's position in its host vehicle (at least two different inserts for a given seat configuration).

[0014] The seat can be equipped with a height adjustment mechanism, in a manner compatible with the characteristics described above. In this configuration, a seat mounting plane is defined (for example, the one passing through the upper ends of the height adjustment links), which may remain parallel to the plane of the longitudinal seat rails, or which may diverge slightly from the plane of the longitudinal rails depending on the kinematic solution chosen for the height adjustment mechanism.

[0015] It should also be noted that the headrest contributes to the cohesion of the seat by firmly and elastically holding the padding against the anti-submarining insert, which presses the latter against the support area provided in the seat frame.

[0016] According to one embodiment, the vehicle seat is located in an orthogonal spatial frame comprising a vertical direction (Z), a longitudinal direction (X) and a transverse direction (Y), the support area is formed as a first support plane, the first support plane generally extending along a transverse direction Y and an inclined vertical direction.

[0017] In practice, the inclined vertical direction is inclined forwards, separated from the ascending vertical by an angle 01, 01 being for example between 25° and 45°.

[0018] The orientation of the first support plane is chosen so that the normal NN to the first support plane is directed towards HX, the point HX being the point in the middle of the basin of the average occupant.

[0019] Advantageously, the bearing surface is flat and optimally oriented to absorb the compressive forces generated by a front impact.

[0020] It is possible that the support area may not be planar; for example, it may be formed as a wavy surface or a continuous succession of inclined planes forming a zigzag support surface. However, these support surfaces collectively represent a planar average support surface whose normal is directed towards point HX.

[0021] According to one embodiment, the seat frame comprises a left side portion, a right side portion, a front cross member extending from the left side portion to the right side portion, and a rear cross member extending from the left side portion to the right side portion, and a bearing face forming the bearing area or the first bearing plane is provided on the front cross member.

[0022] Advantageously, such a seat frame is robust and simple to manufacture, for example by plastic molding. Its cost price is moderate and advantageous.

[0023] It is the front crossmember that absorbs the force transmitted by the anti-submarine insert in the event of a frontal impact. The front crossmember transmits the forces to the lateral portions which are connected to the seat frame.

[0024] Alternatively, the front cross member transmits the forces directly to a metallic front cross member of the base frame of the seat, located for example just behind the bearing face of the seat frame.

[0025] According to one embodiment, the seat frame is attached to the base frame, via attachment means which include in particular hooks provided on the rear cross member, and configured to cooperate with a metal rear cross member of the base frame.

[0026] These fastening means make it possible to effectively secure the seat frame and the base frame.

[0027] This results in good transmission of forces from the base frame to the base reinforcement.

[0028] According to one embodiment, the anti-submarine insert extends along Y between the left lateral portion and the right lateral portion.

[0029] This provides a natural positioning of the anti-submarine insert along the transverse direction.

[0030] Advantageously, the bearing surface between the submersible insert and the support area is substantial and allows for a wide and well-distributed absorption of forces under forward shock.

[0031] According to one embodiment, the anti-submarine insert has inclined sides, with the front part of the anti-submarine insert narrower than the rear part.

[0032] We thus have a V-shaped form, or in other words a wedge-shaped form, which naturally comes to self-center in the seat frame.

[0033] The conicity of the inclined sides can be very small, e.g. a few degrees; this is sufficient to wedge the anti-submarine insert while awaiting the complete assembly of the safety mattress and the cover.

[0034] A low taper also makes it possible to maximize the contact area between the anti-submarine insert and the front cross member of the seat frame on which the insert rests.

[0035] According to one embodiment, studs are provided on the lateral reception faces. The inclined sides hook onto the studs or grooves, which provides effective pre-retention of the anti-submarine insert before assembly of the padding and the cover.

[0036] According to one embodiment, the basic frame comprises a left flange and a right flange, the left lateral portion has an inverted U-shaped section to cover the left flange, the right lateral portion has an inverted U-shaped section to cover the right flange.

[0037] This gives cohesion and solidity to the structural elements of the base.

[0038] According to one embodiment, the seat can be equipped with a seat nose tilting system and / or a seat nose extension system.

[0039] This ensures compatibility of the aforementioned options with the proposed technical solution concerning the anti-submarining function.

[0040] According to one embodiment, the anti-submarine insert has a longitudinal vertical section in the shape of a bridge, straddling the front cross member.

[0041] In other words, the anti-submarine insert has a vertical longitudinal section in the shape of an inverted C, open at the bottom. It fits snugly onto the complementary shape formed by the front cross member of the seat frame. This provides adequate snugness along the longitudinal axis X.

[0042] According to one embodiment, the anti-submarine insert is made of expanded polypropylene (EPP), and the seat frame is made of polypropylene. This promotes the possibility of recycling all or part of the seat at the end of its life, as the aforementioned materials can be included in a recycling stream.

[0043] According to one embodiment, the seat frame is made from a recycled portion of polypropylene. Optionally, the insert material and / or the seat frame material include reinforcing fibers.

[0044] According to one embodiment, the seat further comprises a central fabric that extends across the middle of the seat frame. The central fabric is preferably made of synthetic material. The central fabric has a certain degree of flexibility. The central fabric receives and supports the center of the seat cushioning.

[0045] The present invention also relates to a seat comprising a seat as described above.

[0046] The present invention also relates to a motor vehicle, comprising a seat with a seat as described above.

[0047] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig. 1] schematically represents in perspective view a vehicle seat in which the present invention is implemented, the padding and the seat cover not being shown; - [Fig.2] schematically represents a cross-sectional view of the seat in a vertical median plane, according to a first embodiment of the present invention; - [Fig.3] schematically represents in exploded perspective view a lower portion of a vehicle seat, the seat upholstery cover not being shown; - [Fig.4] schematically represents, in perspective view from below, a lower portion of a vehicle seat, the padding and the seat cover not being shown; - [Fig.5] shows a detailed view of the interface between the anti-submarine insert and the seat frame; - [Fig.6] schematically represents a longitudinal vertical cross-sectional view of the seat in a vertical median plane, according to a second embodiment, with the anti-submarine insert having a bridge-shaped section; - [Fig.7] illustrates geometric construction elements representative of the effectiveness of the anti-submarine function; - [Fig.8] schematically illustrates in perspective an example of an anti-submarine insert.

[0048] In the various figures, the same reference numerals designate identical or similar elements. For the sake of clarity, some elements are not necessarily shown to scale.

[0049] Fig. 1 shows a vehicle seat, of which only the structural elements of the seat ASS and the bottom of the backrest DOS have been represented.

[0050] In the figures, the seat is located with respect to an orthogonal frame as follows: the vertical direction is noted Z, the horizontal direction of the vehicle, called longitudinal, is noted X, the horizontal direction, called transverse, is noted Y, Y is perpendicular to Z and to X.

[0051] We will see later that the longitudinal direction of the seat, and in particular the longitudinal direction of its seat, can be slightly inclined with respect to the reference longitudinal direction X.

[0052] As known per se, the DOS backrest is mounted on the seat frame with a possible adjustment in inclination, i.e. in rotation around a transverse axis denoted Y0.

[0053] As seen in [Fig.1], the seat ASS comprises a base frame 1 and a seat frame 2, which together form the essentially rigid elements of the seat.

[0054] Basic frame

[0055] The basic frame I includes a left flange 11 and a right flange 12. The basic frame 1 is made of metal, particularly steel. The basic frame 1 also includes a rear metal cross member 13 and optionally a front metal cross member 10.

[0056] The metal cross member(s) connect(s) transversely the right flange to the left flange.

[0057] According to a very common arrangement, position adjustment is provided in the longitudinal direction, by means of longitudinal adjustment slides 7

[0058] The longitudinal slides 7 can be unlocked via a control lever 72 (see figures 3 and 4). In some commercial vehicles, there is no such longitudinal adjustment, but passenger vehicles are generally equipped with it.

[0059] According to a fairly common arrangement, a raising movement of the seat relative to the vehicle floor is provided. A system of raising links is provided for this purpose; this system is known per se and therefore not described in detail here. The figures illustrate the lower axes Y1 and Y2 of the raising links and the upper axes Y3 and Y4 of the raising links.

[0060] According to an alternative arrangement, the seat is devoid of a raising movement in which case the basic frame is fixed directly to the upper profiles of the longitudinal slides, or even directly to the floor of the vehicle.

[0061] Advantageously according to the solution proposed here, the basic frame 1 supports a seat frame which carries several technical functions and which is described now.

[0062] Seat frame

[0063] The seat frame 2 includes a left side portion 21, a right side portion 22, a front cross member 20, and a rear cross member 23.

[0064] The front cross member 20 connects transversely the right lateral portion 22 to the left lateral portion 21 in the front area. The front cross member 20 extends from the right lateral portion to the left lateral portion.

[0065] Similarly, the rear cross member 23 connects transversely the right lateral portion 22 to the left lateral portion 21 in the rear area. The rear cross member 23 extends from the right lateral portion to the left lateral portion.

[0066] The seat frame 2 is made of polypropylene material (PP). The polypropylene material can be reinforced with fiberglass, at a rate of 10 to 25%. This material is rigid and exhibits good resistance to alternating stresses and good overall resistance to fatigue.

[0067] The seat frame 2 is made by molding, through which the seat frame can include complex shapes, in particular elements for fixing to the metal frame.

[0068] The right lateral portion 22 of the seat frame has an inverted U-shaped section to cover the left flange 11 of the base frame 1. The right lateral portion 22 has an inverted U-shaped section to cover the right flange 12 of the base frame.

[0069] The seat frame is attached to the base frame 1 via attachment means. In the example shown in the figures, the attachment means include, in particular, hooks 27 provided on the rear cross member 23. The hooks 27, once assembled on the base frame 1, surround the rear metal cross member 13. These may be clip-on hooks.

[0070] Other attachment links may also be provided on the front portion to secure each lateral portion of the seat frame with the corresponding flange of the base frame.

[0071] In the configuration where there is a front crossbar 10 of the base frame as illustrated in [Fig. 6], the seat frame 2 can be attached to the front metal crossbar 10 of the base frame via clip-on hooks. For example, the seat frame 2 can be mounted on the base frame 1 using clips, without screws.

[0072] The front crossmember 20 includes stiffening ribs 28, which gives good strength to the front crossmember 20 which can withstand the stresses suffered during a front impact with a heavy occupant on the seat.

[0073] A bearing surface 25 is arranged on the front crossmember 20, forming a bearing area for a part called an "anti-submarine insert," which will be discussed below. The crossmember 20 includes a concave shape 29 suitable for receiving and housing the anti-submarine insert 4.

[0074] It should be noted that several variants of the seat frame can be provided depending on the seat options.

[0075] For example, the seat can be equipped with a function for extending the seat nose. According to another example, the seat can be equipped with a function for adjusting the height of the seat nose.

[0076] In the middle of the seat frame, a central fabric 6 is provided. The central fabric 6 has a certain flexibility to give a good degree of softness to the seat padding.

[0077] The central fabric is preferably made of synthetic material. The central fabric receives and supports the center of the seat cushion 3. Preferably, the peripheral edge of the central fabric is attached to the seat frame by any means of fastening.

[0078] Anti-submarining insert

[0079] For the anti-submarine function, an anti-submarine insert 4 is provided. The anti-submarine insert 4 is made of expanded polypropylene material.

[0080] The anti-submarine insert 4 is rigid, its Young's modulus is preferably on the order of several hundred MPa, or even more than 1 GPa. It compresses moderately upon the occurrence of a frontal impact and where it prevents the lower part of the occupant's body from sliding.

[0081] The anti-submarine insert 4 is mounted to rest on a support area provided in the seat frame is covered by the foam padding discussed later.

[0082] In the example illustrated according to the first embodiment, the support area is formed as a plane called hereinafter the first support plane PI. The first support plane generally extends along a transverse direction Y and an inclined vertical direction Al as seen in Figures 2 and 7.

[0083] As shown in Figures 2, 6, 7, and 8, the cross-section S4 in a longitudinal vertical plane of the anti-submarine insert is typically a polygon, in particular a quadrilateral. It may be a rectangle, a trapezoid, or any other quadrilateral, as in the illustrated example. The cross-section S4 in question is constant over a substantial length L4 of the insert along the direction; for example, typically the cross-section is constant over at least 25 cm, or even 30 cm.

[0084] As seen in [Fig.8], the anti-submarine insert 4 has long faces, in particular a front face 4A, a rear face 4B, a top face 40 and a bottom face 42. The anti-submarine insert 4 has a left transverse end 4G and a right transverse end 4D.

[0085] The anti-submarine insert 4 has an edge 41 which is closest to point HX. This edge may be slightly beveled and forms a stop ridge along X to prevent the occupant's pelvis from moving forward and to restrain the thighs. The length of the front face 4A of the insert is denoted L4, the height of the front face 4A of the insert is denoted H4, and the height of the rear face 4B of the insert is denoted H3. The The depth of the insert in the longitudinal direction is noted as D4. H4 can be between 3 cm and 6 cm, without the values ​​given here being limiting.

[0086] As illustrated in figures 6 to 8, a beveled face may be provided on the part that is closest to point HX or in other words on the opposite part that comes into the hollow 29 formed in the front cross member of the seat frame.

[0087] The beveled face reduces the feeling of the presence of the anti-submarining insert under the occupant's thighs and contributes to the comfort of the seat while ensuring anti-submarining safety.

[0088] Only the extremities on the right side 4D and the left side 4G have a particularity, which in this case is an inclination giving a wedge shape to the anti-submarine insert.

[0089] As illustrated in [Fig. 5], the front portion of the insert is shorter than the rear portion. The sides of the insert converge towards the front. The resulting taper can be a few degrees, say between 3° and 10°. As already mentioned, this allows the anti-submarine insert 4 to be wedged in place when it is positioned on the front cross member of the seat frame.

[0090] In addition, 8 small studs, also called ribs, may be provided on the receiving sides of the seat frame. This increases the wedging and pre-support effect when the anti-submarining insert is placed in position before the padding is assembled.

[0091] The bearing surface L4 x H4 between the submersible insert 4 and the support area 25 is substantial and allows for a wide and well distributed absorption of forces under forward impact.

[0092] Mattress and cover

[0093] Furthermore, the seat cushion ASS includes a foam padding 3 visible in figures 2 and 3, and a cover 5, shown only in [Fig.2].

[0094] The padding 3 can be made of polyurethane foam. The padding material is preferably cellular. The padding 3 is compressible and returns to its reference shape when no stress is applied.

[0095] The headrest 5 is attached either to the seat frame 2 or to the base frame 1 via a plurality of hooks which allow the headrest to be kept in tension against the padding as known in itself and therefore not described in detail here.

[0096] Regarding the anti-submarining function, we will now illustrate with the help of figures 2 and 7 how the choice of an anti-submarining insert 4 allows to optimize the anti-submarining function.

[0097] The X direction corresponds to the horizontal in the vehicle's frame of reference.

[0098] The W7 direction corresponds to the sliding axis of the slide system. It passes through axes marked Y1 and Y2, which are the lower pivot axes of the lifting links.

[0099] The angle

[31] which separates the directions X and W7 may be zero or may be a few degrees depending on the architecture of the vehicle floor.

[0100] The direction W2 corresponds to the reference plane of the seat, it passes through the axes Y3 and Y4, which are the upper pivot axes of the lifting links.

[0101] The angle (32) separating directions W7 and W2 can vary by a few degrees depending on the vehicle floor design. During a lifting movement, the angle

[32] can change by a few degrees during the lifting stroke, for example.

[0102] The anti-submarine insert 4 is located in the reference frame of the seat here with respect to the direction W2.

[0103] Starting from the basic construction of the seat base as described in the preceding paragraphs, the ideal position of the support plane for the anti-submarine insert is determined. In particular, the normal NN to this support plane at the location of the anti-submarine insert passes through the central point of the occupant's pelvis HX.

[0104] Another criterion, in addition or in combination, may be the position of the vertex 41 of the section of the insert which must be such that the line which passes through this vertex and the point HX makes an angle 02 with respect to the horizontal X.

[0105] Another criterion, in addition to or in combination with the previous ones, may be the forward inclination Al of the support plane which makes an angle 01 with respect to the vertical Z. The normal NN makes an angle 0N with respect to the horizontal X, which is equal to 01.

[0106] In practice, configurations are aimed for where angle 01 is between 25° and 35°. More generally, angle 01 is between 20° and 40°, preferably in the vicinity of 30°.

[0107] Referring to [Fig. 2], a position criterion for point HX relative to the nearest vertex of the anti-submarine insert can be advantageously chosen; thus, dimensions L1 and L2 are target dimensions for optimized operation of the anti-submarine function. The various crash test results accumulated over a wide range of scenarios have helped to refine the target values ​​for the angles and / or distances L1 and L2.

[0108] In any event, it is possible to determine the desired position of the anti-submarine insert, as well as its longitudinal vertical section with respect to point HX in the vehicle frame.

[0109] From the geometric configuration of the seat, the best anti-submarine insert can be chosen in terms of vertical section as well as in terms of size and position relative to point HX.

[0110] Fig. 2 illustrates a first underwater insert marked 4 and a second underwater insert marked 4'. In the illustrated example, the insert marked 4' is larger than the insert marked 4, because the seat is flatter, for example.

[0111] In a very simple geometric configuration we have pl= p2 = 0. 01 is then taken directly with respect to the longitudinal direction.

[0112] In a typical geometric configuration where pl+ p2 is non-zero, the geometric construction of the position of the anti-submarine insert in the seat must take into account the inclination of the seat reference plane W2 with respect to X as illustrated in [Fig.7].

[0113] Figure 6 illustrates an alternative embodiment with a larger anti-submarine insert 4. The anti-submarine insert covers the front cross member 20 of the seat frame, including the frontal portion, up to the front edge 24 of the front cross member 20.

[0114] The anti-submarine insert 4 has a bridge-shaped section, straddling the forward cross member 20.

[0115] The anti-submarining insert 4 is made of EPP which is more recyclable than foam padding.

[0116] In other words, the anti-submarine insert has a vertical longitudinal section in the shape of an inverted C, open at the bottom. It fits snugly onto the complementary shape of the front cross member of the seat frame. This provides adequate snugness along the longitudinal axis X.

[0117] More specifically, the vertical longitudinal section of the insert comprises an anterior portion 44, a main body 45 located above the cross member of the seat frame and a posterior portion 47. A support plane 46 aligned with the axis Al is also provided. The anterior and posterior portions of the insert frame the front cross member of the seat frame.

[0118] As already mentioned, the anti-submarining insert can be chosen according to the application case of the seat and in particular the orientation of its seat relative to the vehicle horizontal.

Claims

Demands

1. Vehicle seat comprising a basic frame (1), a seat frame (2), a foam cushion (3), and a cover (5), characterized in that it provides an anti-submarining insert (4), mounted in support on a support area provided in the seat frame and covered by the foam cushion, the foam cushion being itself covered by the cover.

2. Seat according to claim 1, wherein the vehicle seat is located in an orthogonal spatial frame comprising a vertical direction (Z), a longitudinal direction (X) and a transverse direction (Y), and wherein the support area is formed as a first support plane (PI), the first support plane generally extending along a transverse direction (Y) and an inclined vertical direction (Al).

3. Seat according to claim 2, wherein the seat frame comprises a left side portion (21), a right side portion (22), a front cross member (20) extending from the left side portion (21) to the right side portion (22), and a rear cross member (23) extending from the left side portion (21) to the right side portion, characterized in that a bearing face (25) forming the bearing area or the first bearing plane (PI) is provided on the front cross member.

4. Seat according to claim 3, wherein the anti-submarine insert extends along (Y) between the left lateral portion (21) and the right lateral portion (22).

5. Seat according to any one of claims 1 to 4, wherein the anti-submarine insert (4) has inclined sides, with the front part of the anti-submarine insert narrower than the rear part.

6. Seat according to any one of claims 1 to 5, wherein the seat frame is attached to the base frame (1), via attachment means which include in particular hooks (27) provided on the rear cross member, and configured to cooperate with a metal rear cross member (13) of the base frame.

7. Seat according to any one of claims 1 to 6, wherein the basic frame comprises a left flange (11) and a right flange (12), the left lateral portion has an inverted U-shaped section to cover the left flange (11), the right lateral portion has an inverted U-shaped section to cover the right flange (12).

8. Seat according to any one of claims 3 to 4, wherein the anti-submarine insert (4) has a longitudinal vertical section (S4) in the shape of a bridge, straddling the front cross member (20).

9. Seat according to any one of claims 1 to 8, wherein the anti-submarine insert (4) is made of expanded polypropylene material, and the seat frame (2) is made of polypropylene material.

10. Vehicle comprising a seat with a seat according to any one of claims 1 to 9.

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