Seat frame for vehicle seat with anti-submarining airbag

Abstract

The invention relates to a seat frame (110) for a motor vehicle seat comprising a rigid underbody frame (111) comprising two lateral flanges (112, 113) between which a front crossmember (114) and a rear crossmember (115) extend, an elastic suspension sheet (122) extending between said crossmembers, as well as an anti-submarining airbag (127) comprising an inflatable bag (128) and a gas generator, said inflatable bag extending, in its uninflated configuration, flat so as to cover said suspension sheet and at least a portion (114A) of said front crossmember; characterized in that said inflatable bag comprises: - a primary chamber (128A) fluidly connected to the outlet of said generator and covering said at least a portion (114A) of the front crossmember (114), and, - a secondary chamber (128B) fluidly connected to said primary chamber and extending in the rear extension of this primary chamber.Figure to be published with the abstract: Fig. 1.

Description

Description Title of the invention: Seat frame for vehicle seat equipped of an inflatable anti-submarine cushion technical field

[0001] — The present invention relates generally to the field of seating for motor vehicle.

[0002] = It relates more particularly to a seat frame for such a seat equipped of an inflatable anti-submarining cushion. Previous technique

[0003] In the event of a frontal collision with the vehicle, for example during an accident, the energy The kinetic energy stored by the seat occupant tends to propel their body towards the front. The seatbelt lock helps to keep this occupant in place. seat and to prevent it from being ejected from the vehicle or thrown against the structures of the passenger compartment.

[0004] — The strong deceleration that the body undergoes at this precise moment can, however, lead to its movement relative to the waist, and in particular the sliding of its pelvis along the seat, under the pelvic part of this belt.

[0005] — This movement, which is usually called "submarining", can cause serious bodily injuries, particularly severe abdominal injuries, when the the anterior superior iliac spines of the user's pelvis pass below the pelvic part of the belt, by sliding the user's buttocks on the seat.

[0006] To avoid this phenomenon, patent application is known in particular French standard FR 2 868 997 A1 for anti-submarine devices consisting of a inverted bowl attached to the vehicle floor and whose boss is oriented trans- Versatile. Positioned under the seat's usable position, this basin allows to ensure effective restraint of the occupant in order to prevent the submarining of his pelvis in case of violent impact.

[0007] — Because the bowl is fixed to the floor, this type of solution is however not suitable for seats that are adjustable lengthwise relative to this floor.

[0008] It is also known to provide a tubular anti-submarine bar. extending transversely between two lateral flanges of the base reinforcement of the seat, under the padding.

[0009] = During a frontal collision of the vehicle, the buttocks of the seat occupant come impacting this bar, which deforms by absorbing some of the kinetic energy of the occupant which helps to limit the movement of the pelvis.

[0010] — Unfortunately, the effectiveness of such an anti-submarine bar remains often limited because, in order not to significantly impact seating comfort, it tends to be placed in front of and below the optimal position so that it often acts too late and too violently. European document EP 2 022 685 B1 discloses a seat frame for a motor vehicle seat comprising a rigid subframe including two side flanges between which extend a front cross member and a rear cross member, an elastic suspension sheet extending between said cross members, and an anti-submarining safety airbag including an inflatable bag and a gas generator to ensure the inflation and deployment of said bag. The bag, in its uninflated configuration, lies flat so as to cover the suspension system and part of the front crossbar. When the safety airbag is triggered, the deployment of the bag causes the seat surface to rise, which in turn raises the occupant's femoral area to ensure that the restraining force exerted by the pelvic part of the seat belt is applied against the occupant's pelvis and not at the level of their abdomen. The use of such an inflatable safety cushion has the advantage of not negatively impacting seating comfort (absence of hard spots) and of adapting to very different body sizes. Unfortunately, this type of airbag does not always prevent the dynamic forward movement of the occupant's pelvis under the pelvic part of the seatbelt. Description of the invention The present invention therefore aims to improve the situation. For this purpose, it proposes a seat frame for a motor vehicle seat comprising a rigid base frame including two side flanges between which extend a front cross member and a rear cross member, an elastic suspension sheet extending between said cross members, and an anti-submarining safety airbag comprising an inflatable bag and a gas generator to ensure the inflation and deployment of said bag, said inflatable bag extending, in its uninflated configuration, flat so as to cover said suspension sheet and at least part of said front cross member; characterized in that said inflatable bag comprises: - a primary chamber fluidically connected to the outlet of said generator and covering said at least a portion of the front crossmember, and, - a secondary chamber fluidically connected to said primary chamber and extending in the rear extension of this primary chamber. Such an arrangement of the airbag allows the inflation of the primary chamber to be prioritized over that of the secondary chamber. This priority inflation of the primary chamber causes the initial lifting of the front portion of the seat surface on which rests the front part of the occupant's femoral area extending behind the knees to approximately the middle of the thighs, this lifting effectively limiting the dynamic forward movement of the occupant's pelvis. According to preferred characteristics of said seat frame according to the invention: - said front cross member includes a support wall extending transversely between the two front portions of said side flanges and inclined longitudinally towards the rear and downwards, this support wall being covered by said primary chamber; - said gas generator extends transversely under the rear end of said support wall to which it is fixed; - said primary chamber also covers the front portion of said suspension sheet; - said inflatable bag is kept flat under tension by means of a plurality of connecting elements linking the four sides of this bag respectively to the front cross member, the rear cross member and the two side flanges of said underframe; - said primary and secondary chambers are fluidly connected to each other via a discontinuous transverse seam line made by stitching or laser welding; - said primary and secondary chambers are fluidically connected to each other via a porous partition; - said primary and secondary chambers are fluidically connected to each other via at least one conduit; and / or - said primary and secondary chambers are fluidically connected to each other via at least one valve-type vent, calibrated to open when the pressure in the primary chamber reaches a predetermined value. The invention also relates, in a second aspect, to a motor vehicle seat comprising a seat including such a frame and a covering attached to it. Brief description of the drawings The description of the invention will now be continued by a detailed description of several embodiments, given below by way of illustration but not limitation, with reference to the attached drawings, on which: [Fig.1] is a partial top perspective view of the structure of a vehicle seat comprising a seat frame according to the invention equipped with a safety airbag in its uninflated flat configuration; [Fig.2] represents a partial cross-sectional view along a median vertical longitudinal plane of the seat structure of [Fig.1] whose inflatable safety cushion of the seat frame is also shown in its uninflated, flat configuration; [Fig. 3] is a view similar to that of [Fig. 1] but in which the airbag is shown in its inflated configuration; and [Fig.4] represents a view similar to that of [Fig.2] but in which the airbag is shown in its inflated configuration. Description of the implementation methods Fig. 1 represents a partial perspective view of structure 1 of a front seat of a motor vehicle intended to be mounted on the floor of that vehicle. In the description that follows, and by convention, the terms "lower", "upper", "longitudinal", "lateral" and "transverse" will be defined in relation to the mounting position of such a motor vehicle seat in the passenger compartment of that vehicle. As illustrated in this [Fig.1], the seat structure 1 comprises a seat frame 110 intended to be attached to the vehicle floor and a backrest frame 210. These seat and back frames are intended to be covered each with a respective padding classically consisting of a quilting made generally of expanded foam, as well as a cover covering this quilting and made for example of woven or non-woven material. Intended to be attached to the floor of the vehicle, the seat frame 110 comprises a rigid subframe 111 formed of two sheet metal side plates 112, 113 extending opposite each other in parallel vertical planes and between which extend a front cross member 114 and a rear cross member 115. Also made from a sheet of metal, the front cross member 114 extends fixedly between the two front portions of the side flanges 112, 113 which it covers by laterally wrapping them. This front cross member 114 includes a support wall 114A extending transversely between the two front portions of these side flanges 112, 113, so as to be located vertically above the front portion of the occupant's femoral area extending behind the knees to about the middle of the thighs. Featuring a curved section with its concavity oriented downwards, this support wall 114A slopes longitudinally backwards and downwards. The rear cross member 115 is made up of a steel tube extending transversely between the rear ends of these side flanges 112, 113 and is mounted to rotate freely relative to them. The rear ends of the two side flanges 112, 113 are pivotally articulated with respect to the backrest frame 210 around a transverse axis so as to allow the backrest to tilt relative to the seat. The two flanges 112, 113 are also slidably mounted on the floor of the vehicle by means of a pair of slides 116, so as to allow adjustment of the longitudinal position of the subframe 111 relative to the floor of the motor vehicle. Each slide 116 conventionally comprises a movable rail 16A capable of sliding axially along a fixed rail 116B mounted on the vehicle floor. Rolling elements, not shown, are interposed between these movable and fixed rails. Each of the 116 slides also includes a means, not shown, for locking the movable rail 116A in the corresponding fixed rail 116B. Each of these locking means may, for example, consist of a movable bolt capable of engaging in regularly spaced longitudinal recesses in the rail. These locking means can be unlocked by means of a control device, not shown. Each side flange 112, 113 is also connected to a riser device, so that the base frame 111 can be adjusted in height relative to the floor. This raising device includes: - two front connecting rods 117 pivotally articulated at one end on the front portions of the side flanges 112, 113 and at the other on front support feet 118 fixedly mounted on the front portions of the movable rails 116A of the slides 116; and - two rear connecting rods 119 fixed at one end to the rear cross member 115 and pivotally articulated at the other on rear support feet 120 fixedly mounted on the rear portions of the mobile rails 116A of the slides 116. The height adjustment of the subframe 111 is thus obtained by pivoting the connecting rods 117, 118 driven by a mechanism controlled by a control lever 121 extending transversely between the two front connecting rods 117. The seat frame 110 also includes an elastic suspension web 122 supported by the front 114 and rear 15 cross members and comprising several crenellated metal wires 123 extending longitudinally between the latter and arranged at regular intervals over the width of the seat frame 111 (see [Fig.3]). The suspension mat 122 further includes a plurality of hooks 124 arranged at both ends of each of the crenellated wires 123 and allowing to secure its attachment to the front cross members 114 and rear cross members 115. These serrated wires 123 are further joined together by connecting spacers 125 allowing for better distribution of the forces exerted on them when an occupant is seated on the seat. The suspension sheet 122 is also attached to the two side flanges 112, 113 by means of fastening straps 126. The seat frame 110 also includes an anti-submarine safety inflatable cushion 127. This safety airbag 127 classically comprises an airbag 128, as well as a gas generator 129 comprising a rigid metal container of generally cylindrical shape in which are contained reagents enabling the generation of gas and an electrically controlled trigger. The gas generator 127 includes at one of its ends an electrical connector allowing the trigger to be electrically connected to the vehicle's electrical network in order to control the safety airbag 125. As illustrated in [Fig.2], the gas generator 129 extends transversely under the rear end of the support wall 114A of the front cross member 114 to which it is fixed by mounting means not shown. The 128 inflatable bag is classically formed by two superimposed sheets of fabric joined at their peripheral edges by a continuous seam line made by sewing or laser welding. Alternatively, bag 128 could be made from a single sheet of fabric folded in half lengthwise and joined on three sides of its periphery by means of a continuous joining line. With further reference to [Fig.2], this inflatable bag 128, in its uninflated configuration, lies flat so as to cover the suspension sheet 122 and the support wall 114A of the front cross member 114. This airbag 128 is thus intended to be sandwiched between, on the one hand, this suspension mat 122 and this front cross member 114, and on the other hand, the seat upholstery not shown. In order to prevent its movement or the folding of some of its portions onto each other, the inflatable bag 128 is advantageously kept flat under tension by means of a plurality of connecting elements not shown and linking the four sides of this bag respectively to the front cross member 114, the rear cross member 115 and the two side flanges 112, 113. These connecting elements are, for example, made up of straps attached at one end to one side of the bag and equipped at their other end with a hook secured to a corresponding element of the subframe. When the safety airbag 127 is triggered by the emission of an electrical signal generated during a frontal collision of the vehicle with another vehicle or an obstacle such as a pole, the gas generator 129 sends pressurized gas into the airbag 128 which inflates as illustrated in Figures 3 and 4. According to the invention and as illustrated in the figures, the inflatable bag 128 comprises: - a primary chamber 128A fluidly connected to the outlet of the gas generator 129 and covering the support wall 114A of the front crossmember 114, as well as advantageously the front portion of the suspension strut 122; and - a secondary chamber 128B extending in the rear extension of the primary chamber 128A, this secondary chamber 128B being fluidly connected to the primary chamber 128A by means of a discontinuous transverse joint line 128C (see [Fig.1]) made by stitching or laser welding. As illustrated by figures 3 and 4, such an arrangement of the inflatable bag 128 allows the inflation of the primary chamber 128A to be prioritized over that of the secondary chamber 128B. This priority inflation of the primary chamber 128A results in the initial lifting of the front portion of the seat surface on which rests the front part of the occupant's femoral area extending behind the knees to approximately the middle of the thighs, this lifting limiting the dynamic forward movement of the occupant's pelvis. It should be noted that the fact that this primary chamber 128A rests on the inclined rigid support wall 114A of the front cross member 114 allows its inflation to be guided upwards and backwards so as to optimally reduce the dynamic forward movement of the occupant's pelvis. Furthermore, it will be noted in support of [Fig.3] that the fact that this primary chamber 128A extends, in its flat uninflated configuration, beyond the wall 114A and also covers the front portion of the suspension layer 122 makes it possible to take into account the phenomenon of longitudinal retraction of the bag 128 during its inflation so as to maximize the bearing surface of this primary chamber 128A against this wall 114A. Secondly, the inflation of the secondary chamber 128B prevents the occupant's pelvis from sinking too far into the rear part of the seating surface. According to alternative embodiments not shown, the primary chamber 128A and secondary chamber 128B can be fluidly connected by a porous partition wall. According to other unrepresented embodiments, the primary chamber 128A and secondary chamber 128B can be fluidically connected by at least one conduit. Such a conduit may be made, for example, of a flexible hose advantageously made of nylon 6-6, this flexible hose preferably having an internal diameter between 5 and 10 mm, and a thickness between 1 and 1.5 mm. Such a conduit can also be made up of an inflatable tube formed by the bag 128 and delimited by two parallel longitudinal seam lines extending between these two chambers. According to yet other unrepresented embodiments, the primary chamber 128A and secondary chamber 128B can be fluidly connected via at least one valve-type vent, calibrated to open when the pressure in the primary chamber reaches a predetermined value. Finally, it is recalled that the present invention is not limited to the embodiments described and represented, but also encompasses all variants of execution within the reach of a person skilled in the art. The frame could, for example, be shaped differently and be devoid, for example, of a riser device or sliding guide means.

Claims

Demands

1. Seat frame (110) for motor vehicle seat comprising a rigid base frame (111) comprising two flanges lateral (112, 113) between which extends a front cross member (114) and a rear crossmember (115), an elastic suspension sheet (122) extending between the said crossbeams (114, 115), as well as a cushion inflatable anti-submarine safety life jacket (127) including a bag inflatable (128) and a gas generator (129) to ensure inflation and the deployment of said bag, said inflatable bag (128) extending, in its uninflated configuration, flat so as to cover said tablecloth suspension (122) and at least a portion (114A) of said front crossmember (114); characterized in that said inflatable bag (128) comprises: - a primary chamber (128 A) fluidically connected to the outlet of said generator nerator (129) and covering said at least a part (114A) of the front cross member (114), and, - a secondary chamber (128B) fluidly connected to said chamber primary (128A) and extending in the rear extension of this primary chamber (128A).

2. Seat reinforcement (110) according to claim 1, characterized in that said front cross member (114) includes a support wall (114A) extending transversely between the two front portions of said lateral flanges (112, 113) and inclined longitudinally towards rearward and downwards, this supporting wall (114A) being covered by said primary chamber (128A).

3. Seat reinforcement (110) according to claim 2, characterized in that said gas generator (129) extends transversely under the end rear of said support wall (114A) to which it is fixed.

4. Base reinforcement (110) according to any one of claims 1 to 3, ca- characterized in that said primary chamber (128A) also covers the front portion of said suspension sheet (122).

5. Seat frame (110) according to any one of claims 1 to 4, ca- characterized in that said inflatable bag (128) is kept flat under tension via a plurality of connecting elements the four sides of this bag respectively to the front crossbar (114), to the rear cross member (115) and to the two side flanges (112, 113) of said base frame (111).

6. Seat frame (110) according to any one of claims 1 to 5, ca- characterized in that said primary (128A) and secondary chambers {128B) are fluidly connected to each other via of a discontinuous transverse seam line (128C) made by sewing or laser welding.

7. Seat frame (110) according to any one of claims 1 to 5, ca- characterized in that the said primary and secondary chambers are connected fluidly to one another via a partition wall porous lining,

8. Seat frame (110) according to any one of claims 1 to 5, ca- characterized in that the said primary and secondary chambers are connected fluidly to one another through at least one conduct.

9. Seat frame (110) according to any one of claims 1 to 5, ca- characterized in that the said primary and secondary chambers are connected fluidly to one another via at least one vent of valve type, calibrated to open when the pressure in the primary chamber reaches a predetermined value.

10. Motor vehicle seat comprising a seat including a frame (110) and a fitting attached thereto, characterized in that said frame (110) conforms to any one of claims 1 to 9,