MOTOR VEHICLE WITH ENHANCED FRONT-END IMPACT SAFETY

Abstract

The invention relates to a motor vehicle (100) comprising a chassis (20) with longitudinal frame members (30) carrying lower supports (1), comprising a movable support (50) carrying a movable accessory (40) which allows limited longitudinal recoil relative to said chassis (20) during a frontal impact, this movable support (50) comprising upper supports (2) each sliding relative to a lower support (1) by means of a longitudinal slot in this lower support (1) and an assembly screw perpendicular to the slot and arranged to push a fusible wedge against a stop surface of the slot during a frontal impact until it deforms or breaks. Abstract figure: [Fig. 7]

Description

Title of the invention: MOTOR VEHICLE WITH ENHANCED FRONT-END IMPACT SAFETY

[0001] The invention relates to a motor vehicle, capable of moving in a straight line along a longitudinal direction, perpendicular on flat ground to a vertical direction which is that of the gravitational field, a transverse direction being orthogonal to both the longitudinal direction and the vertical direction, and comprising a body with a chassis having longitudinal shafts extending along said longitudinal direction and each carrying a lower support arranged to carry, directly or indirectly, at least one movable accessory.

[0002] The technical field concerns the protection against shock of components installed on a support, via a defined kinematic.

[0003] In order to limit the intrusion of front-end components into the passenger compartment of a motor vehicle following a frontal impact, a limit on the installation of these components, along the longitudinal direction of the vehicle, is professionally referred to as the "thin impact wall." Adherence to this limit restricts intrusions into the passenger compartment to a specified value.

[0004] Deformable devices capable of absorbing the energy of an impact to protect vehicle occupants are known in the prior art. However, this arrangement generates additional constraints on the installation of the components to ensure compatibility with the thin impact wall in a crash test.

[0005] The objective of the present invention is to remedy these drawbacks by proposing the use of special components which are called "fusible wedges", to allow in the event of a frontal impact the longitudinal displacement of the support cross member (and the various components fixed to it), so that its final position (end of impact) is compatible with the specified "end of impact wall".

[0006] To achieve this objective, the invention proposes a motor vehicle, capable of moving in a straight line along a longitudinal direction, perpendicular on flat ground to a vertical direction which is that of the gravitational field, a transverse direction being orthogonal to both the longitudinal direction and the vertical direction, and comprising a body with a chassis having longitudinal shafts extending along said longitudinal direction and each carrying a lower support arranged to carry, directly or indirectly, at least one movable accessory.

[0007] According to the invention, said chassis comprises a movable support arranged to allow limited recoil, along said longitudinal direction, of said at least one movable accessory relative to said chassis during a frontal impact, said movable support comprising at least one upper support arranged to carry said at least one movable accessory and arranged to slide relative to said lower support according to a predefined sliding-type kinematic with end stops, said lower support comprising at least one longitudinal slot, extending along said longitudinal direction, and in which is movable an assembly screw extending perpendicularly to said longitudinal slot which comprises a first stop surface and a second stop surface, said chassis further comprising fusible wedges each interposed between a said assembly screw and said second stop surface, each said fusible wedge being deformable between a rest position in which said fusible wedge is free and holds said assembly screw against said first stop surface,and an end-of-impact position corresponding to the limit of the stroke of said at least one moving accessory during a frontal impact, and in which said assembly screw pushes said fusible wedge onto said second stop surface.

[0008] Thus the fusible wedges allow a limited stroke, and ensure the longitudinal stop of the mobile accessory carried by the mobile support before the end wall of impact or just at its level.

[0009] Advantageously, said at least one movable accessory is, during a frontal impact, guided along said longitudinal direction X by the cooperation between each said assembly screw and each said corresponding longitudinal slot.

[0010] The trajectory of the moving support is thus linear and controlled.

[0011] Advantageously each said assembly screw cooperates with minimal radial play with each corresponding said longitudinal slot.

[0012] The resting position is thus maintained without vibration.

[0013] Advantageously, the stiffness of each said fusible wedge is compatible with the nominal forces at its interfaces, and each said fusible wedge is arranged to exceed its elastic limit and / or to break in the event of a frontal impact above a predetermined frontal force.

[0014] Experimentation during crash tests makes it possible to determine the physical characteristics of the fusible wedges, which guarantee reproducible behavior from one vehicle to another.

[0015] More specifically, each of said fusible wedges is arranged to break in the event of a frontal impact above a predetermined frontal force.

[0016] Thus it can absorb part of the energy of the shock.

[0017] More particularly, said assembly screw extends along said transverse direction or along said vertical direction.

[0018] Its assembly is thus facilitated.

[0019] Advantageously, said mobile support is a transverse support comprising at least two said upper supports cooperating by sliding with two said lower supports parallel to each other.

[0020] The whole is thus well balanced, and the efforts distributed, minimizing the torque effect.

[0021] More particularly, said chassis includes a front bumper connected to said longitudinal beams by damping means.

[0022] It is thus possible to absorb part of the energy of the shock.

[0023] More particularly, said chassis includes a front bumper connected to said longitudinal beams by at least one deformable area arranged to dissipate at least part of the energy of a frontal impact.

[0024] It is thus possible to absorb part of the energy of the shock.

[0025] 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 illustrates, in top view, a part of the chassis of a motor vehicle according to the invention (the front of which is in the direction of the hollowed-out arrow), comprising two shafts carrying a movable support arranged to allow limited recoil, in a longitudinal direction, of a movable accessory relative to the chassis during a frontal impact; the left part of the figure shows a lower support comprising slides in which screws attached to an upper support visible in the right part of the figure are movable; during an impact, each screw compresses a fusible wedge enclosed in the slide, and deforms or breaks it according to the intensity of this frontal impact; a reference surface of the movable accessory, represented by a dashed line, is then longitudinally distant from a limit represented by a solid line called the "end wall of impact"; - [Fig.2] schematically illustrates the detail of the mobile support of [Fig.1], the The slide has a first stop surface, on which the screw rests in the rest position, i.e. in normal operating mode of the vehicle, and a second stop surface, opposite the first, on which the fusible wedge rests, held by the screw, and against which this fusible wedge is compressed by the screw during a frontal impact; - [Fig.3] schematically illustrates, similarly to [Fig.1], the same deformed assembly during a frontal impact represented by a solid arrow; the screws have left the support on the first stop surface, and crush the fusible wedges on the second stop surface; the reference surface coincides with the "end wall of impact" limit; - [Fig.4] schematically illustrates, similarly to [Fig.2], the same deformed assembly during a frontal impact according to [Fig.3]; - [Fig. 5] schematically illustrates the mobile support, in cross-section in a plane vertical parallel to the longitudinal direction, at the top in the rest position, and at the bottom in the position following a frontal impact; - [Fig.6] schematically illustrates the front part of the vehicle, in elevation, in the resting position; - [Fig.7] schematically illustrates the vehicle, in elevation, in the position resting position in solid line, and in the recoil position of the mobile crew after a frontal collision, in dashed line.

[0026] A motor vehicle 100, capable of moving in a straight line along a longitudinal direction X, perpendicular on flat ground to a vertical direction Z which is that of the gravity field, is schematically illustrated in [Fig.1], with a transverse direction Y being orthogonal to both the longitudinal direction X and the vertical direction Z.

[0027] The invention consists of defining a movable support 50, movable along the longitudinal direction X during a frontal impact, such that the installation of the components located above it, hereinafter referred to as the "movable accessory 40," is compatible with the thin impact wall M. This movable accessory 40 has a reference surface, located in front of the thin impact wall M under normal operating conditions, and which approaches or reaches it during a frontal impact. The purpose of this boundary is to protect the vehicle's passenger compartment 90, its occupants, and its equipment during a frontal impact, by preventing the intrusion of the movable accessory 40, typically positioned at a height relative to the lower part of the chassis 20 and its frame members 30.

[0028] The invention aims to increase the architectural efficiency by installing components beyond the thin wall impact limit, and thus to allow the crushing of a more dimensioned rear stretcher area.

[0029] For this purpose, the invention implements a mobile support 50, in particular transverse, retractable during a frontal impact.

[0030] This mobile support comprises at least two parts sliding relative to each other, creating between them a defined and imposed kinematic of the sliding type.

[0031] More particularly the mobile support 50 includes a lower support 1, arranged to be fixed on a stretcher 30 which comprises the vehicle 100. It also includes an upper support 2, which is mounted to slide on or in the lower support 1, under the application of a longitudinal force greater than a predetermined threshold.

[0032] In a first variant, the upper support 2 is mounted with clamping on or in the lower support 1, and is only mobile relative to it beyond the application of a first predetermined force.

[0033] In a second variant, the upper support 2 is mounted sliding just on or in the lower support 1, and is only mobile relative to it beyond the application of a second predetermined force, which is less than the first predetermined force.

[0034] Advantageously, the movable support includes at least one fusible wedge 5 interposed between a first bearing surface of the lower support 1 and a second bearing surface of the upper support 2.

[0035] Advantageously, the mobile support 50 is substantially symmetric with respect to a median plane PM, which passes through the center of inertia of the vehicle 100, and which is parallel to the longitudinal direction X and the vertical direction Z.

[0036] More particularly, the lower support 1 includes at least one lower arm which is arranged to slide on or in an upper arm which is included in the upper support.

[0037] More particularly, the movable support 50 comprises at least one pair of such lower arms cooperating by sliding with as many upper arms. More particularly still, these lower arms on the one hand, and these upper arms on the other hand, are symmetrical with respect to the median plane PM.

[0038] Advantageously, each sliding assembly, comprising a lower arm and an upper arm, includes at least one fusible wedge 50 interposed between a first bearing surface of the lower arm and a second bearing surface of the upper arm.

[0039] Each fusible wedge 50 is calculated with a stiffness compatible with nominal forces at its interfaces, and is designed to break during a frontal impact, beyond the first predetermined force, or the second predetermined force depending on the type of assembly chosen.

[0040] More particularly, the mobile support 50 comprises a plurality of such sliding assemblies, each comprising a lower arm and an upper arm enclosing such a fusible wedge, and each sliding assembly comprises a wedge of different stiffness, so as to allow successive rupture of the different wedges depending on the frontal force applied.

[0041] The breaking of the fusible wedges releases the longitudinal movement of the upper support along the longitudinal direction X, via longitudinal light slides present in the lower support.

[0042] Fixing screws 4 create a screwed assembly of the supports together.

[0043] More particularly, as illustrated by the figures, such a motor vehicle 100 is capable of moving in a straight line along a longitudinal direction X, perpendicular on flat ground to a vertical direction Z which is that of the gravity field, a transverse direction Y being orthogonal to both the longitudinal direction X and the vertical direction Z, and comprises a body 10 with a chassis 20.

[0044] This chassis 20 includes longitudinal stretchers 30 extending along the longitudinal direction X, and each carrying a lower support 1 arranged to carry, directly or indirectly, at least one movable accessory 40.

[0045] According to the invention, the chassis 20 comprises a movable support 50, which is arranged to allow limited recoil, along the longitudinal direction X, of at least one movable accessory 40 relative to the chassis 20 during a frontal impact. To this end, the movable support 50 comprises at least one upper support 2, which is arranged to carry such a movable accessory 40, and which is arranged to slide relative to a corresponding lower support 1, according to a predefined sliding-type kinematic arrangement with end stops.

[0046] The lower support 1 has at least one longitudinal slot 3, extending along the longitudinal direction X, and in which is movable an assembly screw 4 extending perpendicularly to the longitudinal slot 3, which has a first stop surface 31 and a second stop surface 32, opposite each other along the longitudinal direction X.

[0047] The chassis 20 also includes fusible wedges 5, each interposed between an assembly screw 4 and the second stop surface 32, each fusible wedge 5 being deformable between a rest position in which the fusible wedge 5 is said to be free and maintains the assembly screw 4 in contact with the first stop surface 31, and an end-of-impact position corresponding to the limit of the stroke of the movable accessory 40 during a frontal impact and in which the assembly screw 4 pushes the fusible wedge 5 onto the second stop surface 32.

[0048] More particularly, the movable accessory 40 is, during a frontal impact, guided along the longitudinal direction X by the cooperation between each assembly screw 4 and each corresponding longitudinal slot 3.

[0049] More specifically, each assembly screw 4 cooperates with minimal radial play with each corresponding longitudinal slot 3.

[0050] More particularly, the stiffness of each fusible wedge 5 is compatible with the nominal forces at its interfaces, and each fusible wedge 5 is arranged to exceed its elastic limit and / or to break in the event of a frontal impact above a predetermined frontal force.

[0051] More specifically, each fusible wedge 5 is arranged to break in the event of a frontal impact above a predetermined frontal force.

[0052] More specifically, the assembly screw 4 extends along the transverse direction Y or along the vertical direction Z.

[0053] More particularly, the mobile support 50 is a transverse support comprising at least two upper supports 2 cooperating by sliding with two lower supports 1 parallel to each other.

[0054] More particularly, the chassis 20 includes a front bumper 60 connected to the longitudinal beams 30 by damping means 70, such as shock absorbers, springs, or others.

[0055] More particularly, the chassis 20 includes a front bumper 60 connected to the longitudinal beams 30 by at least one deformable zone 80 arranged to dissipate at least part of the energy of a frontal impact.

Claims

1.

2. Demands Motor vehicle (100), capable of moving in a straight line along a longitudinal direction (X), perpendicular on flat ground to a vertical direction (Z) which is that of the gravity field, a transverse direction (Y) being orthogonal to both the longitudinal direction (X) and the vertical direction Z, and comprising a body (10) with a chassis (20) comprising longitudinal shafts (30) extending along said longitudinal direction (X) and each carrying a lower support (1) arranged to carry, directly or indirectly, at least one movable accessory (40), characterized in that said chassis (20) comprises a movable support (50) which is arranged to allow limited recoil, along said longitudinal direction (X), of said at least one movable accessory (40) relative to said chassis (20) during a frontal collision,said movable support (50) comprising at least one upper support (2) arranged to carry said at least one movable accessory (40) and arranged to slide relative to said lower support (1) according to a predefined sliding kinematic with end stops, said lower support (1) comprising at least one longitudinal slot (3), extending along said longitudinal direction (X), and in which is movable an assembly screw (4) extending perpendicularly to said longitudinal slot (3) which comprises a first stop surface (31) and a second stop surface (32), said chassis (20) further comprising fusible wedges (5) each interposed between said assembly screw (4) and said second stop surface (32), each said fusible wedge (5) being deformable between a rest position in which said fusible wedge (5) is free and holds said assembly screw (4) against said first stop surface (31),and an end-of-impact position corresponding to the limit of the stroke of said at least one moving accessory (40) during a frontal impact and in which said assembly screw (4) pushes said fusible wedge (5) onto said second stop surface (32). Motor vehicle (100) according to claim 1 characterized in that said at least one movable accessory (40) is, during a frontal collision, guided along said longitudinal direction (X) by the cooperation between each said assembly screw (4) and each corresponding said longitudinal light (3).

3. Motor vehicle (100) according to claim 1 or 2 characterized in that each said assembly screw (4) cooperates with minimal radial clearance with each corresponding said longitudinal slot (3).

4. Motor vehicle (100) according to any one of claims 1 to 3 characterized in that the stiffness of each said fusible wedge (5) is compatible with the nominal forces at its interfaces, and in that each said fusible wedge (5) is arranged to exceed its elastic limit and / or to break in the event of a frontal impact above a predetermined frontal force.

5. Motor vehicle (100) according to any one of claims 1 to 4 characterized in that said assembly screw (4) extends along said transverse direction (Y) or along said vertical direction (Z).

6. Motor vehicle (100) according to any one of claims 1 to 5 characterized in that said movable support (50) is a transverse support comprising at least two said upper supports (2) cooperating by sliding with two said lower supports (1) parallel to each other.

7. Motor vehicle (100) according to claim 6, characterized in that the transverse support is substantially symmetric with respect to a median plane (PM), which passes through the center of inertia of said motor vehicle (100), and which is parallel to said longitudinal direction (X) and to said vertical direction (Z).

8. Motor vehicle (100) according to any one of claims 1 to 7 characterized in that said chassis (20) comprises a front bumper (60) connected to said longitudinal shafts (30) by damping means (70).

9. Motor vehicle (100) according to any one of claims 1 to 8 characterized in that said chassis (20) comprises a front bumper (60) connected to said longitudinal beams (30) by at least one deformable zone (80) arranged to dissipate at least part of the energy of a frontal impact.

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