Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/34—Protecting non-occupants of a vehicle, e.g. pedestrians
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/34—Protecting non-occupants of a vehicle, e.g. pedestrians
  • B60R2021/343—Protecting non-occupants of a vehicle, e.g. pedestrians using deformable body panel, bodywork or components

Definitions

• TITLE Deformable tie for the maintenance of a lower cross member of a windshield bay of a motor vehicle
• the present invention relates generally to the field of design of structural elements of the body of motor vehicles, and more particularly to the problem of passive safety of motor vehicles in the event of an impact of the motor vehicle with a pedestrian.
• It relates to a deformable tie rod for maintaining a lower cross member of a collapsible windshield bay of a motor vehicle, a set of structural elements of the body of a vehicle comprising such a cross member thus maintained, as well as a motor vehicle incorporating such an assembly.
• Passive safety of a motor vehicle designates all the means that come into action in a motor vehicle during an accident in order to minimize its severity for the occupants of the vehicle and / or for people outside the vehicle and involved in the accident.
• passive safety is based on the ability of structural elements of a motor vehicle to absorb the energy of a shock when it occurs. This is particularly the case for collisions between the vehicle and a pedestrian. In the event of such a collision, the structure of the vehicle must be able to deform so as to absorb energy throughout the impact, through a programmed deformation, in order to minimize the consequences of the impact for the pedestrian struck.
• the motor vehicle approval protocol notably requires a large number of tests aimed at checking compliance with standards concerning the absorption of a vehicle shock with the legs, femur or even the head of a pedestrian.
• the European evaluation programs EuroNCAP from the English “European New Car Assessment Program”
• Chinese ChinaNCAP from the English “China New Car Assessment Program”
• the so-called "pedestrian impact - head” test thus aims, as its name suggests, to test a simulated impact between the head of a pedestrian and a motor vehicle.
• the performances associated with the impact of the head of a pedestrian which are examined both by the approval protocol and by the evaluation programs only concern the impact of the head of a pedestrian with the hood of the vehicle.
• the stiffness of the material from which the cover is made must therefore allow its deformation, which generates the most progressive deceleration. possible from the head of a pedestrian during an impact with this external structural element.
• a structural element of the vehicle which is deformable in itself can be prevented from deforming properly during an impact due to its arrangement and / or the other surrounding structural elements.
• Obtaining good performance in terms of passive safety therefore also relies on the adequate use, in the impact zone considered, of so-called “fuse” parts, that is to say parts which deform, break or eject during an impact so as not to offer a hard point.
• the homologation protocol and the evaluation programs will introduce new requirements aimed in particular at the impact of the head of a pedestrian. Shots simulating such a shock must be made specifically in the area at the bottom of the windshield located at the front of the vehicle, at the junction between the hood and the windshield. These tests must imperatively lead to results deemed admissible to obtain certification, or to obtain the maximum point during an evaluation. In other words, certain biomechanical criteria for a pedestrian impact, which until now have been optional, will probably become essential to pass the approval protocol and / or to obtain good marks in the framework of the evaluations according to the EuroNCAP and ChinaNCAP programs.
• TIB lower windscreen bay cross member
• the TIB present on current models of motor vehicles are not "collapsible". They are in themselves rigid and are, moreover, supported by mechanical reinforcing parts which are also rigid. These parts are rigidly supported on an element of the vehicle body to constitute an additional reinforcement preventing any collapse of the Tl B in the event of an impact.
• the existing Tl B are in fact designed to be rigid in order in particular to offer good performance in terms of minimizing the vibrations potentially transmitted by the TIB from the engine compartment towards the interior of the passenger compartment. They are said to offer good acoustic and vibratory performance (ACV). However, they are not compatible with the aforementioned future passive safety standards, which should soon be imposed by the approval protocol and / or the evaluation programs of motor vehicles.
• Document FR 2892019 discloses a hood structure which allows the hood to collapse, in the rear region of the hood, at the junction with the windshield, so as to close the separation hole between these two elements and thus avoid '' cause even greater damage to the pedestrian in the event of an impact.
• the target sag is that of the hood, not that of the lower windshield bay cross member. It therefore remains rigid and capable of causing a sudden deceleration of the head of a pedestrian during an impact.
• the invention aims to eliminate, or at least mitigate, all or part of the disadvantages of the aforementioned prior art.
• a first aspect of the invention provides a deformable tie rod for holding a lower cross member of the windshield bay of a motor vehicle, said deformable tie rod having a first end part, a second part d end and a central part which extends longitudinally between the first end part and the second end part, said tie rod comprising:
• a deformable blade extending in the longitudinal direction of the tie rod, in the central part of the tie rod, from the first end part to the second end part of the tie rod;
• a first reinforcing plate with a flat part extending substantially parallel to the blade at the level of the first end part of the tie rod and with fallen edges by which it is connected to the blade at the level of the first part d end of the tie rod to form with said blade a first stiffness box, said first plate being adapted to be connected to the crosspiece by the face of its flat part which is opposite to the blade;
• a second reinforcing plate with a flat part extending substantially parallel to the blade at the second end portion of the tie rod and with fallen edges by which it is connected to the blade at the second part d end of the tie rod to form with said blade a second stiffness box, said second plate being adapted to be connected to another structural element of the body of the motor vehicle by the face of its flat part which is opposite to the blade;
• the blade is substantially flat in the central part of the tie rod, and extends in a plane which is not parallel to the plane in which the flat part of at least one of the first and second plates extends, so that, when the lower cross member of the windshield bay collapses following an impact, the deformable tie folds at the junction between the corresponding end part and the central part of the tie.
• TIB windscreen bay
• Embodiments of the tie rod taken individually or in combination, further provide that:
• the blade has, in the central part of the tie rod, a zone of variation of width adapted so that, when the lower cross member of the windshield bay collapses following an impact, the deformable tie rod bends at said blade width variation zone;
• a rib which extends in a direction parallel to the longitudinal direction of the tie rod, from an edge of the plate which is contiguous to the central part of the blade and over a determined portion only of the length of the plate in said direction;
• the blade and the reinforcement plates of the tie rod are made of a flexible metal alloy, and in which the blade and / or the reinforcement plates of the tie rod have a thickness of approximately 1 millimeter; and,
• tie rod according to the invention to maintain the TIB of a motor vehicle makes it possible to make the TIB collapsible to meet future passive safety requirements relating to impact with the head of a pedestrian, while retaining the same level of LCA services.
• the invention also relates to a set of structural elements of the body of a motor vehicle.
• a set of structural elements of the body of a motor vehicle comprising a lower cross member of a collapsible windscreen opening and at least one deformable tie according to the first aspect above, for maintaining said cross member to another structural element of the body.
• Embodiments taken individually or in combination, further provide that:
• the other structural element of the body of the motor vehicle to which the lower cross member of the windscreen bay is held by means of the tie rod is an upper apron of the body;
• the assembly also comprises a canopy collector, and the position of the zone of variation of the width of the blade of the tie rod in the longitudinal direction of said blade is adapted to avoid, when the lower cross member collapses. windshield bay following an impact, a bracing between the deformable tie rod and the upper part of the awning collector; and,
• the lower cross member of the collapsible windshield bay is made of a metal alloy and has a thickness of less than 1 millimeter, for example equal to approximately 0.95 millimeter.
• a final aspect of the invention relates to a motor vehicle comprising at least one set of structural elements according to the second aspect above.
• FIG. 1 is a perspective view of a lower cross member of the windscreen bay held by support parts according to the prior art
• FIG. 2 is a perspective view of embodiments of a deformable tie rod according to the invention
• FIG. 3 is a perspective view of an example of the use of tie rods such as the tie rod of FIG. 2, for holding a windscreen bay cross member on a body structure element of a motor vehicle; and,
• FIG. 4 is a schematic representation of the results of a modeling illustrating the evolution, during an impact with the head of a pedestrian, of the deformation of a TIB maintained by a deformable tie rod according to FIG. 2.
• Figure 1 shows in perspective a lower cross member of a windshield bay (TIB) of a motor vehicle, which is held by support parts according to the prior art.
• this cross member 101 is designed so as to be rigid so as, in particular, not to transmit the acoustic waves and the vibrations from the engine compartment towards the passenger compartment. As a result, it cannot collapse in an impact to absorb impact energy.
• This rigid TIB is supported by also rigid mechanical parts, namely retaining brackets 103 in the example shown, which bear on another structural element of the body of the motor vehicle. More specifically, in the example shown, the brackets 103 are supported on the upper bulkhead 102 of the motor vehicle.
• the TIB is in fact not likely to collapse under the effect of an impact and therefore cannot absorb, if necessary, the impact of the head of a pedestrian who would strike this area of the vehicle. .
• the design and layout of all of these parts therefore prevent any deformation of the vehicle structure in this area of the vehicle, in the event of an impact with the head of a pedestrian.
• FIG. 2 shows in perspective embodiments of a deformable tie rod 200 according to the invention, which we will then see that it allows the production of a collapsible TIB.
• the deformable tie rod 200 comprises a blade 201 which is made of a metal alloy such as for example flexible steel.
• the thickness of the blade 201 is, for example, equal to 1 millimeter. This relatively small thickness notably makes it possible to locally obtain a capacity for deformation of the tie rod at the level of the blade, to which we will return later. This thickness value is purely indicative.
• the tie may be made of synthetic material.
• the use of a plastic material capable of supporting the cataphoresis process and having the characteristics adapted to the desired deformation results in a high material cost and a manufacturing cost. This is why a preferable metal alloy construction.
• the blade 201 of the tie rod 200 has a longitudinal direction which, in FIG. 2, is oriented substantially along the vertical.
• the upper elements of the tie rod are located at the top and the lower elements are located at the bottom, in FIG. 2.
• the terms “vertical (e)” and “horizontal (e)”, “(en ) top ”and“ bottom ”,“ upper ”, and“ lower ”, etc., are used with reference to this representation of the tie rod.
• the deformable tie rod 200 comprises a central part 203 which is flexible, and two end parts which are rigid, namely an upper end part 202 and a lower end part 204, respectively. These end parts 202 and 204 are adapted for, and intended for fixing the tie rod to the structural elements of the body of the vehicle which the tie rod assists in assembling and maintaining between them.
• the central part 203 of the tie rod 200 comprises only the flexible blade 201.
• This central part 203 can therefore be the threshold of a deformation, as will be explained below.
• the upper end part 202 of the deformable tie rod 200 comprises the upper end of the blade 201. It also comprises a reinforcing plate 205 which is for example substantially rectangular and extends in a vertical plane, parallel to the plane of the blade 201 in this end portion 202 of the tie rod.
• the width of the plate 205, along the horizontal, corresponds substantially to the width of the blade 201 locally.
• the plate 205 has for example fallen edges 206, which extend longitudinally along the vertical in the configuration shown in FIG. 2.
• the fallen edges 206 correspond to a curvature or a fold of the vertical edges of the plate 205. They are oriented along the horizontal, towards the blade 201, substantially perpendicular to the plane of the plate 205 and the blade 201 in this end portion 202 of the tie rod.
• the curvature or bending of the edges 206 of the plate 205 gives this part a section in the shape of a "U" in a horizontal plane.
• the base of this "U" which corresponds to the flat part of the plate 205, is adapted to be fixed, for example by welding, to a first structural element of the vehicle to which the tie rod 200 is fixed by its upper end 202.
• the face of the plate 205 which is opposite to the face blade 201 and which is visible in FIG. 2, includes a zone 213a for receiving an electrical welding point (PSE).
• PSE electrical welding point
• the two branches of the "U" which correspond to the fallen edges 206 of the plate 205, are substantially orthogonal to the plane of the planar part of said plate 205, and orthogonal to the blade 201 in the upper end part 202 of the tie rod 200
• the blade 201 closes the box formed by the flat part of the plate 205 and its two fallen edges 206.
• the plate 205 is assembled by welding the ends of the fallen edges 206 on the blade 201 of the tie rod 200.
• This shape and this arrangement of the plate 205 give rigidity to the upper end part 202 of the tie rod 200, to prevent any deformation locally.
• the upper end portion 202 of the tie rod 200 is suitable for rigid attachment of the tie rod to a first structural element of the motor vehicle.
• the planar base of the plate 205 also includes a rib 207, which is centered horizontally between its two fallen edges 206, and which extends vertically upwards, from the lower edge of the plate 205, over a determined portion of the height of said plate along the vertical.
• the rib 207 gives rigidity to the plate 205, in order to limit its deformation capacity.
• the zone 213a intended to receive the EPS is located just above the upper end of the rib 207, in the extension of said rib.
• the lower end portion 204 of the deformable tie rod 200 also comprises a reinforcement plate 208, symmetrically comparable to the reinforcement plate 205 of the upper end part 202.
• the plate 208 is substantially rectangular, with fallen edges 209 which are orthogonal to the plane and the plane platinum zone and which extend horizontally towards the blade 201 in the lower end part 204 of the tie rod 200.
• the end part 204 of the tie rod 200 also includes a rib 210, centered along the horizontal between the fallen edges of the plate 208, and which extends vertically downwards, from the upper edge of the plate 208, over a determined portion of its height.
• the flat face of the plate 208 is intended to come into contact with another element of the vehicle to which the tie rod 200 is fixed by its lower end 204, and for this purpose comprises a zone 213b to receive another PES.
• This zone 2013b may be located just below the lower end of the rib 2010, in the extension of said rib.
• the blade 201 remains flexible in its central part 203, that is to say between the end parts 202 and 204, which extends longitudinally (ie along its length) between the end part upper 202 and the lower end portion 204 of the deformable tie rod 200. In order to maintain this flexibility and its total deformation capacity, it preferably has neither fallen edges, nor rib, nor reinforcement.
• the flat faces of the plates 205 and 208 of the two end parts 202 and 204, respectively extend in respective planes, namely vertical planes and parallel to each other in the example considered here and shown in the Figure 2, but separate.
• the central part of the blade extends, in its longitudinal direction with a slight angle relative to the respective planes of the plates 205 and 208 of the end parts 202 and 204, respectively, of the tie rod 200.
• a force applied vertically to the pulling 200 via one or other of its end parts 202 and 204 has the effect of causing the deformation, in particular the buckling, of the central part 203 of the tie which is flexible because it only comprises the blade flexible 201.
• the blade 201 in the central part 203 of the tie may locally have a zone 21 1 of variation of its width.
• it is a linear variation in the longitudinal direction of the blade, according to a V-shaped profile, going for example from the widest to the least wide from the upper part towards the lower part of the blade 203.
• the role of this zone of variation of the width 21 1, which will be explained later with reference to FIG. 4, is to create a rupture of inertia which allows programmed deformation of the part central
• the deformable tie rod is fixed integrally with the latter, on the one hand, and with another element of the body of the motor vehicle, on the other hand.
• the deformable tie rod 200 is welded to the TIB by its upper end part 202, and to a second structural element of the chassis of the motor vehicle by its lower end part 204.
• this second structural element is the upper deck 102 of the chassis of the motor vehicle.
• the fixing of the deformable tie rod 200 with the lower cross member of the windscreen bay and with another structural element of the chassis of the motor vehicle is obtained by two points of electrical welding (PSE).
• PSE points of electrical welding
• These two EPS are located respectively on the flat part of the plate 205 of the upper end part 202 (at the level of the zone 213a) and on the planar part of the plate 208 the lower end part (at the level of the zone 213b), above or below, respectively, ribs 207 and 210, respectively, plates 205 and 208, respectively.
• Such single point fixings make it possible to locate this point in a particularly reinforced area (thanks to the rib). This prevents the fasteners from breaking during an impact and allows better control of where the deformation (s) of the tie rod will occur if necessary.
• it may be a fixing by screw or bolt, or by any other suitable fixing means.
• FIG. 3 shows an example of use of tie rods conforming to tie rod 200 of FIG. 2. More specifically, the figure illustrates an embodiment of a set of structural elements of the chassis of a motor vehicle which comprises a cross member lower windshield bay 301 and three deformable tie rods 200 which hold this TIB. The tie rods hold the TIB to another structural element of the vehicle chassis, for example to the upper bulkhead 102 in the example shown. This element separates the engine compartment from the passenger compartment of the vehicle. In Figure 3, the TIB and its tie rods are seen from the engine compartment.
• the TIB is designed to be deformable in itself, due to its thinness.
• the TIB is made of a metal alloy, for example steel, and has a thickness reduced to around 1 mm, for example 0.95 mm, in order to give it good bending capacity.
• the reinforcements of the TIB are also reduced to what is strictly necessary to guarantee good flexibility of the TIB in the event of an impact with the head of a pedestrian.
• the geometry of the TIB is such that it can, in itself, collapse and not create a hard point, while being favorable to respecting the constraints of acoustic and vibratory filtration (called constraints ACV).
• the tie rods 200 have the function of maintaining the TIB by preventing it from transmitting vibrations from the engine to the passenger compartment.
• the tie rods are arranged on the side of the engine compartment.
• the fact that the tie rods are also deformable makes it possible to obtain a flexibility of the connection between the TIB and the upper deck 102.
• the TIB thus designed and maintained thus becomes collapsible, which will enable vehicles to be approved when the new requirements passive safety systems will come into effect.
• the TIB can advantageously not only collapse under the effect of an impact so as to absorb the shock, but it is also held firmly enough to allow limit the transmission of acoustic waves and vibrations from the vehicle engine to the passenger compartment.
• the use of such an assembly therefore does not entail any additional noise or vibration nuisance compared to the prior art in which the TIB is rigid and non-deformable.
• the number of deformable tie rods used, as well as their arrangement and their distribution along the TIB, can be chosen in order to optimize the compromise between maintaining the TIB by the tie rods which guarantees compliance with the constraints. on the one hand, and the effect shock absorption with the head of a pedestrian in the TIB area, on the other hand, according to the specifics of each application.
• FIG. 4 there will now be described a sequence of images illustrating the deformation as a function of time of a TIB maintained by a deformable tie rod according to FIG. 2 at the time of an impact with the head of a pedestrian. .
• These images correspond to the results obtained from a finite element calculation method making it possible to model the behavior of the different mechanical parts involved, under the effect of such an impact.
• the four images shown in Figure 4 illustrate the chronological evolution of the state of each element, respectively at the initial instant (0 milliseconds), that is to say at the precise moment when the impact of the head d 'a pedestrian with the TIB zone, then respectively at 6, 10 and 20 milliseconds (ms) after this impact.
• This chronological evolution is done in the order indicated by the arrows 307 in FIG. 4.
• the head of a pedestrian 303 strikes the windshield 302 supported by the lower cross member of the windshield bay 301 which is itself held by the deformable tie 200 visible in the figure.
• the central blade of the tie rod locally has a zone of variation of its width results in a second programmed deformation of the tie rod, with a fold of the blade 201 in a specific place along its longitudinal direction.
• the central part 203 of the blade 201 of the deformable tie rod 200 bends, firstly, at the junction 212 and between its part d 'upper end 202 and this central part 203, secondly, at the level of the zone 21 1 of variation of the width of the blade 201 under the effect of the impact with the head of the pedestrian.
• the zone 21 1 of variation of the width of the blade 201 in the central part 203 of the tie rod 200 is located at two thirds of the length of the blade starting from its lower end part, in the upper half of the central part of the tie rod.
• the TIB used in this context is a TIB itself designed to be flexible enough to be able to crash into response to the impact.
• the TIB is made of steel 0.95 millimeters thick, which is weak enough to allow its deformation.
• a person skilled in the art will know how to adapt the deformable tie rod to avoid, when the lower cross member of the windscreen bay collapses, a bracing between the deformable tie rod and another structural element of the chassis of the motor vehicle. Such bracing can indeed occur, for example, between the deformable tie rod and the upper part of a canopy collector 306 of the chassis.
• This element of the vehicle body structure has the function, as a person skilled in the art is aware of, of collecting and discharging rainwater which trickles from the windshield.
• the dimensions and the shape of the tie rod are adapted to avoid that, during its deformation following a collapse of the TIB, part of the tie rod comes to bear on the upper part of the awning collector, which could stop its deformation.
• tie rods in accordance with embodiments as described in the foregoing makes it possible to propose a collapsible TIB to withstand the so-called “pedestrian-head” impact but also to satisfy the ACV constraints. Indeed, the fixing of the TIB by these tie rods improves the acoustics in the bottom area of the windshield and provides a certain torsional stiffness, which reduces the transmission of vibrational phenomena.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Body Structure For Vehicles (AREA)
• Vibration Dampers (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=65951794

Family Applications (1)

Country Status (5)

Family Cites Families (10)

• 2018
  • 2018-12-06 FR FR1872412A patent/FR3089471B1/fr active Active
• 2019
  • 2019-11-22 EP EP19839640.0A patent/EP3891026A1/de active Pending
  • 2019-11-22 CN CN201980080359.5A patent/CN113165596A/zh active Pending
  • 2019-11-22 WO PCT/FR2019/052786 patent/WO2020115392A1/fr unknown
  • 2019-11-22 US US17/298,403 patent/US20210402951A1/en not_active Abandoned

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