FR2949397A1 - Safety accidental shock dampening structure for backrest frame of rear seat of e.g. station wagon, has shock dampening zones arranged at ends of bar before blocking ends of frame of backrest to chassis by flanges integrated with chassis - Google Patents

Abstract

The structure has shock dampening zones (3) arranged at ends of a pivoting bar (2) before blocking fixation ends of a frame of a backrest (1) during rotation to a chassis of a vehicle by flanges. The flanges are integrated with the chassis of the vehicle. The pivoting bar and the frame of the backrest are formed of a fabricated single piece. The dampening zones are interposed between the pivoting bar and a connecting tube (14) secured to the backrest frame.

Description

The present invention relates to a safety structure of motor vehicle seats in case of accidental shock, by gradual absorption of energy by deformation of a plasticizing zone at the axis of articulation of the backrest on the seat.

French Patent No. 06 01148 in the name of the Society for Research, Studies and Valorization (Sorev) describes a device for damping shock by plastic deformation at the joint of the backrest on the seat of a motor vehicle seat comprising, at this level, a rigid cylindrical central bar forming a spacer of the seat seat and on which is encased, with a slight clearance, a concentric tubular bar integral with a rigid structure for protecting the backrest; twist-deformable portion under the action of a torsion force being arranged on one of these bars, one end of this deformable portion being secured to the rigid central bar, the other end being secured to the integral tubular bar the rigid structure of protection of the backrest whose pivoting under the action of a shock will be cushioned by this deformation in torsion.

The forces exerted by such a rigid structure in the event of a frontal impact of the vehicle, transmitted either by the upper anchorage of a safety belt which it is normally equipped with, or more directly for rear seats by the impact of baggage thrown against the vehicle. backrest, or in case of rear impact by placing the occupant on its backrest, are thus damped by the torsional deformation of the deformable portion. The progressiveness of the damping is ensured by the helical twist of a deformable part of the concentric tube, whose cylindrical tubular shape is maintained by its direct bearing on the rigid central bar or by means of a sleeve of support. A good regularity of damping can be reinforced by the enveloping of the deformable part, with a weak game, in a second concentric external tube limiting the radial deformations towards the outside during the twisting and which can serve as sleeve ensuring a trimming of stiffness progressive or support the backrest frame.

The present invention relates to a damping device of the same nature, but simplified in that the backrest frame and the pivot bar are made in one piece, generally in welded construction, the shock absorption zones by torsion deformation being arranged in each end of the pivot bar, shortly before the ends locked in rotation of fixing the frame of the backrest to the chassis of the vehicle.

This simplified structure ensures a distribution of the damping forces on each end of the pivot bar, and therefore on the vehicle structure by minimizing the weight of the backrest frame by removing any assembly and therefore reducing its cost of construction. From this basic structure, different adaptations are possible, depending on the type of seat and the type of vehicle to which it is intended to adapt.

However, for certain vehicles of the "break" or "minivan" type comprising three rows of seats and whose axis of the amounts of the backrest passes through the axis of the mechanisms allowing their adjustment and by the axis of the bar of absorptioin of energy, if this structure is acceptable for the seats of the third row, it is not the same for the seats of the second row and possibly the first because the rigid cylindrical central bar forming spacer seat of the seat , located in the lower part of the rear seats, does not allow the passage of the feet of the occupants of the row of rear seats. It is therefore necessary to raise it, which also involves raising the adjustment mechanisms and significantly increases the height of the seats, particularly when it is planned to fold the backrest on the seat.

This elevation will be avoided by the interposition of integral gussets of the energy absorption bar whose axis will be different from that of the amounts of the backrest and mechanisms supporting this bar. The angle thus formed will not only raise the bar height but also adjust its position along the longitudinal axis of the vehicle relative to the seat and optimize the position of comfort of the occupant compared at the bottom of the file. Adjustment of the reclining position of the backrest can be obtained either by a tilt adjustment sleeve or by mechanisms fixed on the gussets and offset axially, thus freeing the space necessary for the passage of the feet.

Such a backrest frame structure fixed on a bar with energy absorption interposed allows the use of a curved backrest shell of the type used for the seats of the seat which allows to separate the stress constraints supported by the frame of a seat likely to accommodate any occupant in any vehicle of the "comfort & design" part that can be adopted to customize the seat in the best conditions according to its destination, without however question its structure.

The implementation of this new structure according to the invention with a view to a generalized application has made it necessary to solve problems of weight and bulk.

First, in terms of safety, it is imperative to differentiate the rear impact of the front impact and limit forward / backward strokes of the folder. Currently, according to the state of the art with regard to the force limiters integrated in the seat belt retractors, when a force greater than the setting of the force limiter is exerted, in the event of an accident, on the safety belt, the passenger moves as long as the force he exerts on the belt is greater than the stress limiter setting (and can reach up to 40 cm) hence the need to remedy this displacement by airbags.

According to the invention, jaw claws that can be obtained directly by laser cutting in a single piece such as a tube supporting the two parts of the clutch in the form of a complete subassembly easy to make and insert into the structure, these remaining parts indexed and linked to each other by breakable points, will differentiate the rear impact of the front impact and limit forward / backward strokes of the folder.

While the mechanisms currently used for seat belt, with a diameter of about 120 mm and a weight of 1 kg, pose a problem of space, especially for the flattening of the backrest and the passage of the gluteus occupying the narrow seats, the compact mechanisms according to the invention, of the order of 43 mm in diameter and a weight of 0.7 Kg can retain efforts of the order of 2000 Nm by freeing the passage of the feet .

The control of the mechanism according to the invention is provided by a coaxial traction control arranged axially inside the pivot bar.

Various embodiments of a seat back reinforcement safety device according to the invention will be described hereinafter with reference to the appended drawings of which: FIG. 1 represents in axial section a damping structure according to FIG. invention for a central beam seat seat and seat belt reinforcement, - Figure 1a shows a locking profile in rotation of the end of the pivot bar. FIG. 2 shows, in axial section, an alternative embodiment of a damping structure according to the invention for a seat back frame with a side girder onboard belt with a lined tubular pivoting bar and deformation damping zones in FIG. torsion reported at the end, 15 - Figure 3a schematically shows the need for elevation of the mechanism and the pivot bar of the current seats to fold the backrest horizontally given the volume of its upholstery, - Figure 3b, shows a variant of pivoting diagram of a backrest according to the invention for folding it horizontally without having to raise its pivot axis, because of an inclined and appropriate offset of its attachment ends, - Figure 4 shows in partial axial section an exemplary embodiment of a backrest frame according to the invention with pivot axis at the ends shifted and inclined selo 3 is a partial sectional view according to FIG. 4a; FIG. 5 shows a variant of the preceding structure, applied to backrest frames with lateral beams fixed at the ends offset from the pivot bar; FIG. 6 is an axial sectional view of an example of a central beam reinforcement pivot bar that can accommodate thrust trimming jaws, as shown in partial section 6a for back end limit limitations according to examples of angular values. 6 shows an axial section of an embodiment of a structure with angular stop dogs according to FIG. 6a, FIG. 8 shows in axial section an alternative embodiment of a structure. FIG. with angular stop dogs according to FIGS. 6a and 7 above with discontinuous mechanism for trimming angular positions arranged in an end offset from the bar pivoting reel formed of a section connected to the central bar by a welded perpendicular gusset; - FIG. 8a shows a developed view of the cleats that can be used with the mechanism of FIG. 8; FIGS. 9, 9a and 9b show in FIG. axial and transverse section an alternative embodiment of the offset end of the pivot bar formed of a section connected to the central bar by two longitudinal gussets, - Figure 10 shows in axial section an example of discontinuous mechanism trimming of angular positions arranged in the offset ends of the pivot bar formed of a section connected to the central bar by two longitudinal gussets according to the structure of Figure 9, - Figure 11 shows in axial section an alternative embodiment of a mechanism angular position control of the type described in FIG. 8, controlled with multidirectional output by traction cable. FIG. 12 shows a variant of the mechanism of the type of FIGS. 8 and 11 with rigid traction pull control. - Figures 13, 14, 15 and 16 show, in axial and transverse sections, an embodiment 20 of jaw clutches. In Figure 1, the backrest frame 1 and the pivot bar 2 are formed in one piece, welded construction, torsion deformation damping zones 3 being arranged in each end of the bar 2, shortly before the ends 4 locked in rotation of fixing the backrest frame 1 by the flange 5 to the chassis of the vehicle. FIG. 1a shows an example of a rotational locking profile of the end of the pivot bar that can be obtained by cold kneading of the end of bar 4. In a manner known per se, rings 6 may be provided. of limitation of the dampings by torsional deformations and including jaws 7 of abutting end of travel forward and rear and attenuated protection against the rear impact, covering the deformation zones 3. In this basic example, an absorption 1700 Nm of energy will result for each damping zone 3, thus distributing the forces, the energy absorption of the rear impact being identical to that of the front impact.

FIG. 2 shows, in axial section, an alternative embodiment of a damping structure according to the invention for a seatback reinforcement with an onboard lateral beam belt 1 integral with a lightened tubular pivot bar 2 and comprising zones torsion deformation damping 3 reported at the end.

These zones requiring a more massive tubular structure than the lightened tube 2 are arranged in a tubular part 8 made integral with the tube 2 by a plug-type weld 9 and having at its other end 4 locked in rotation for fixing the backrest frame. 1 to the chassis 5. The distribution of the lines of force in the structure thus produced is indicated by a set of reinforced continuous lines and arrows 10.

FIG. 3a schematically shows, for seats of seats of the state of the art, the need for elevation at 13 of the axis 11 of the pivoting bar of the seat and of the mechanism for folding the backrest horizontally taking into account the volume of its upholstery 12,

FIG. 3b shows that such an elevation is not necessary by using a backrest frame 1 according to the invention, the pivoting bar 2 of which has angularly offset ends providing a space for housing the upholstery 12 when the backrest 1 is folded down. in horizontal position.

FIG. 4 shows an example of backrest frame 1 and its pivoting bar 2 according to the invention, constituted in a single piece, in welded construction, the ends of the pivot bar being offset along bent arms A and B and inclined according to the diagram of Figure 3b, in partial section according to Figure 4a. In this example, the torsionally deformable parts 3 are interposed between the pivot bar 2 and a connection tube 14 integral with the backrest frame 1.

FIG. 5 shows in greater detail this connection at the end of the central bar 2 with a backrest frame side beam 1, the tubular deformable part 3 being interposed between the pivot bar 2 and a connection tube 14 integral with the backrest frame 1, the opposite ends of this deformable tubular portion 3 being respectively secured by circular weld seams 15 of the pivot bar 2 and the connecting tube 14, thus connecting the backrest frame 1 to the bar of pivoting 2 through the deformable tubular portion 3. FIG. 6 shows an assembly between the backrest frame 1 and the pivot bar 2 of the type of the structure described in FIG. 4, 4a having torsionally deformable portions 3 interposed between the pivot bar 2 and a connection tube 14 integral with the backrest frame 1. In a variant according to FIG. 6a, the deformable tubular portion 3 is provided with jaw angular trimming device 16, as indicated in partial section for modulating the rear impact and back end limit limitations according to examples of angular values indicated in FIGS. 6b and 6c. FIG. 7 shows in axial section an exemplary embodiment of FIG. a structure with angular stop dogs according to Figure 6a above. The circular weld 18 assembly of two sections of the pivot bar 2 is made accessible by axial sliding of the tube 14 in position 17, clearing the weld area. It is then brought back into position to effect the weld 19 ensuring the immobilization connection of the backrest between the tube 14, base of the backrest frame 1 and the pivot bar 2, through the deformable tubular portions 3.

FIG. 8 shows, in axial section, an alternative embodiment of a structure with angular abutment jaws 16 according to FIGS. 6a and 7 above with a discontinuous mechanism for setting angular positions 20, with traction cable control 21 and return spring 22 arranged in an offset end 23 of the pivot bar 2 formed of the housing of the mechanism connected to the central bar 2 by a welded perpendicular gusset 24. FIG. 8a shows a developed view of the cleats, for example at a 30 ° pitch allowing a memorized return and can be used with this mechanism. The cleats can be replaced by fine grooves to obtain a fine trimming step of between 6 and 3 °. Such an angular position trimming mechanism 20 is installed in each of the ends of the pivot bar 2. The opening of these two mechanisms are controlled simultaneously by a single handle.

Figures 9, 9a and 9b show in axial and transverse section an alternative embodiment of the structure of Figure 8 in which the offset end 23 of the pivot bar 2 is formed of a section connected to the central bar 2 by two longitudinal gussets 25.

As indicated in FIG. 10, this structure can receive a discontinuous mechanism for trimming angular positions 20 according to the structure of FIG. 9 arranged in this offset end of the pivot bar 2 formed of the section connected to the central bar 2 by two gussets longitudinal 25 as shown in Figure 10a. This type of assembly by longitudinal welds will have the advantage of not soaking the pivot bar 2 only locally in the axial direction and not on its periphery as in the case of a circular weld. Figure 10b shows a developed view of the cleats that can be used with this mechanism.

Figures 11 and 12 show in axial section alternative embodiments of the structure of the discontinuous mechanism for trimming angular positions 20 as described for Figures 8 and 10 and arranged in the offset end of the central pivot bar 2 and connected to this central bar, not shown, by two longitudinal gussets 25. The sleeve 39 forming the offset end of the central bar is fixed to the chassis of the vehicle by the flange 5. In these mechanisms 20, immobilization in rotation of the shifted housing 23 is ensured by the displacement of a sleeve-shaped nut 33 pulled by a pin 26 under the action of a connecting head 27 controlled either by a cable 21 against a spring 22 (FIG 11), or by a control rod 36 (FIG 12), centered by a centering ring 32 sliding in the bore of the sleeve 39 and whose end exiting through a cover 30 has a thread 34 for connection to a linkage coaxial control by traction.

The displacement of the nut 33, ensuring the angular immobilization of the housing 23 is obtained by the pin 26 which bears on the ends of the lights 35 arranged in the axis for, on the one hand, with the stop 29, to avoid the compression of contiguous turns of the spring 22 and secondly, with the stop 28, maintain the assembled mechanism, ready to be put in place in the housing 23.

The disengagement of the mechanisms is ensured, in the example of Figure 11, a cable traction with multidirectional output 31 over 360 ° with the possibility of traction up to 180 ° relative to the axis of the mechanism. The end of the cable 21 is connected to the pin 26 by a connecting piece 27, preferably made of Zamak alloy comprising two perpendicular cylindrical portions, one tubular with a clearance allowing the passage of the pin 26, the other being overmolded on the cable 21.

In the example of FIG. 12, the mechanism is disengaged by rigid traction consisting of a pull tab 36 having a threaded exit end 34, a centering ring 32 and a polar keying head 27 pierced for the passage of the pin 26.

The jaws of abutment angular adjustment 16 are used, independently and complementarily, for performing two functions: - The first is intended to modulate the increase in load of the front (AV) and rear (AR). - The second aims to limit the angular displacement AV and AR of the folder.

The jaws 16 / 1-16 / 1 'and 16 / 2-16 / 2' according to Figure 14 are composed of a movable part and a fixed part connected by breakable points 38, each of these parts can be indifferently secured to either a plasticizing zone 3 or 3 'or the backrest support tube 14, as shown in FIGS. 13 and 14, either simultaneously of the two at a time, or of the pivot bar 2, and form a subset constituted of a single piece of preferentially tubular, cylindrical and uniform section, the jaw being made in the interlocked position by laser cutting to obtain by means of breakable points 38 a perfect indexing of the fixed and movable parts.

In the example of FIG. 13, more specifically reserved for third row seats, a single dog 16 / 1-16 / 1 'is used to modulate the front and rear shocks as shown in FIG. A of Figure 14.

For the AV impact, the dog clutch 16/1 moves clockwise and is already in abutment on the clutch 16/1 ', the plasticizing zone 3' is therefore requested at the same time as the zone 3, which corresponds to the fastest scalability.

Taking into account the biomechanical criteria, it is possible to soften the initial shock by shifting the abutment 16/1 'represented at 0 ° to, for example, 7 or 8 ° to initially leave the only zone of plastification 3, the zone 3 'intervening in a deferred manner.

For the shock AR, the mobile clutch 16/1 moves counterclockwise, the lamination zone 3 working alone for 20 °, as shown in FIG. 15, the zone 3 'starting from this angle coming, if necessary, in complement.

In the example of FIG. 14, two claws are used which perform different functions.

The first clutch 16 / 1-16 / 1 'provides AV and AR boost modulation as described for FIG. 13. It also makes it possible to solve the problem of the shock AR, Low speed 16 km / h, using the plasticizing zone 3 on an angular displacement angle 15 of the backrest, as an example of 20 °, then for the shock AR High speed 34 km / h having a limit stop obtained with the clutch 16/2 at a programmed angle of 30 °.

The second clutch 16 / 2-16 / 2 'as shown in Figure 16 in a cross section B of Figure 14 ensures the limitation of the angular displacement of the folder. For the AV impact, the movable clutch 16/2 moves clockwise and abuts on the fixed clutch 16/2 'after, for example, a stroke of 50 ° backrest. For the shock AR, the movable clutch 16/2 moves counterclockwise and abuts on the fixed claw 16/2 ', after, for example, an angular displacement stroke of 30 ° backrest.

Claims (17)

Claims1- Motor vehicle seat safety structure in which the backrest frame (1) and its pivoting bar (2) consist of a single piece of welded construction, characterized in that damping zones to shocks by torsional deformation are arranged in each end of the pivot bar (2), shortly before the ends (4) locked in rotation of attachment of the backrest frame (1) to the chassis of the vehicle by flanges (5) secured to the chassis of the vehicle .. 2- motor vehicle seat safety structure according to claim 1 characterized in that a seat back frame with side girder belt is integral with a lightened tubular pivot bar (2) having damping zones by torsional deformation reported at the end. 3- safety structure of motor vehicle seat according to claims 1 and 2 characterized in that end torsion damping zones (3) reported at the end consist of a tubular structure more massive than the lightened tube (2). ) and arranged in a tubular piece (8) secured to the tube (2) and having an end (4) locked in rotation for fixing the backrest frame (1) to the chassis (5) of the vehicle. 4- motor vehicle seat safety structure according to claims 1, 2 and 3 characterized in that the ends of the pivot bar (2) are offset in angled arms (A, B) inclined, the parts deformable by torsion (3) being interposed between the pivot bar (2) and a connecting tube (14) integral with the backrest frame (1). 5- safety structure motor vehicle seat according to claims 1, 2, 3 and 4 characterized in that an offset end (23) extends the pivot bar (2). Motor vehicle seat safety structure according to Claims 1, 2, 3, 4 and 5, characterized in that a discontinuous adjustment mechanism for angular positions (20) with traction cable control (21) and return spring (22) is arranged in an offset end (23) of the pivot bar (2). 7- motor vehicle seat safety structure according to claims 1, 2, 3 ,, 4, 5 and 6 characterized in that the offset end (23) of the pivot bar (2) is formed of a housing (23) connected to the central bar (2) by two longitudinal gussets (25), said housing receiving a discontinuous mechanism for setting angular positions (20) arranged in this offset end (23) of the pivot bar (2) and whose central sleeve (39) is connected to a flange (5) integral with the chassis of the vehicle. 8- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6 and 7 characterized in that in the discontinuous mechanism for trimming angular positions (20), controlled by traction cable ( 21) and return spring (22) arranged in an offset end (23) of the pivot bar (2), immobilization of the casing of the offset end (23) is ensured by the displacement of a shaped nut. sleeve (33) pulled by a pin (26) under the action of a connecting head (27) controlled by a cable (21) against a spring (22). 9- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7 and 8 characterized in that, in the discontinuous mechanism for setting angular positions (20), with cable control traction (21) and return spring (22) arranged in an offset end (23) of the pivot bar (2), immobilization of the housing of the shifted abutment (23) is ensured by the displacement of a nut in the form of a sleeve (33) pulled by a control rod (36), centered by a centering ring (32) sliding in the bore of the sleeve (39) and whose end exiting through a lid (30) comprises a thread (34) for connection to a traction coaxial control linkage. 10- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7, 8 and 9 characterized in that the pivot bar (2) of central beam frame (1) is provided with angular trimming jaws (16) for end-of-travel file limitations. 11- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 characterized in that the jaw (16 / 1-16 / 1 ', 16 / 2-16 / 2 ') are composed of a movable part and a fixed part connected to breakable points (38), each of these parts being integral with a plasticizing zone (3) or (3') and comprising a sub-assembly consisting of a single piece of preferentially tubular, cylindrical and uniform section, the jaw being made by simultaneous laser cutting of the fixed and movable parts whose axial and angular relative positions are fixed by the breakable points (38). ). 12- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 characterized in that the claws (16 / 1-16 / 1 ', 16 / 2-16 / 2 ') are composed of a movable part and a fixed part connected to breakable points (38), each of these parts being secured to the support tube of the backrest and forming a subassembly consisting of a only piece of preferably tubular, cylindrical and uniform section, the jaw being made by simultaneous laser cutting of the fixed and movable parts whose axial and angular relative positions are fixed by the breakable points (38). 13- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 characterized in that the jaw (16 / 1-16 / 1 ', 16 / 2-16 / 2 ') are composed of a movable part and a fixed part connected to breakable points (38), each of these parts being integral with the pivoting bar (2) and constituting a subset constituted by of a single piece of preferentially tubular, cylindrical and uniform section, the jaw being made by simultaneous laser cutting of the fixed and movable parts whose relative axial and angular positions are fixed by the breakable points (38). 14- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 characterized in that the connecting tube (14) is integral with one of its ends of a first damping zone (3) whose end is fixed to the pivot bar (2), the other end of the connecting tube (14) being integral with a second damping zone ( 3 ') secured to the movable part (16/1) of a clutch, the fixed part (16/1') of the same clutch being fixed to the pivot bar (2). 15 15- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 and 14 characterized in that the connecting tube (14 ) is integral with one of its ends of the movable part (16/1) of a clutch, the fixed part (16/1 ') of the same clutch being fixed at one end of the damping zone (3). ') whose other end is fixed to the pivot bar (2), the second end of the connecting tube (14) being fixed to the movable part (16/2) of a clutch integral with the damping zone (3) fixed at its end to the pivot bar (2), the fixed part (16/2 ') of the clutch being connected to the pivot bar (2). 16- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7, 8 and 9 characterized in that the discontinuous mechanism (20) of angular position setting is equipped with cleats allowing a memorized return. 17- motor vehicle seat safety structure according to claims 1, 2, 3, 4, 5, 6, 7, 8 and 9 characterized in that the discontinuous mechanism (20) of angular position adjustment is equipped with small grooves allowing a fine trimming. 20