WO2015090987A1

WO2015090987A1 - Dashboard cross-member with a side support having a mixed metal-plastic structure

Info

Publication number: WO2015090987A1
Application number: PCT/EP2014/076508
Authority: WO
Inventors: Jean Michel Appasamy; Eddy Pennerath
Original assignee: Peugeot Citroen Automobiles Sa; Rehau Sa
Priority date: 2013-12-18
Filing date: 2014-12-04
Publication date: 2015-06-25
Also published as: FR3014817B1; FR3014817A1

Abstract

The invention relates to a method for producing a cross-member (1) for the dashboard of a vehicle, comprising at least one cross-bar (2) and at least one side support (3) arranged to allow the cross-bar (2) to be secured to a vehicle body pillar. The method is characterised in that it comprises: a step (a) of producing the side support, comprising the production of a plate (4), from a first material, that is designed to be secured to a body pillar of the vehicle, after which a support sleeve (5) is mounted on and secured to the plate (4), said support sleeve being designed to receive the cross-bar (2) and being made from a second material different from the first and formed by a thermoplastic polymer; and an assembly step (b) during which the cross-bar (2) is secured in the support sleeve (5).

Description

TRAVERSE FOR DASHBOARD WITH SIDE SUPPORT WITH MIXED METALLO-PLASTIC STRUCTURE

The present invention relates to the general technical field of body parts of vehicles, including motor vehicles, and more particularly that of the dashboard crosspieces.

It is known to have, transversely to a vehicle, opposite the apron which separates the engine compartment from the passenger compartment, a cross member which joins a left lateral upright of the bodywork of said vehicle to a right lateral upright of said bodywork. , and which is intended to form a support for the steering column and for the various instruments and panels of the dashboard.

Usually, as described in particular in document US-2010/0176262, the sleepers are made in the form of mechanically welded structures, fixed to the vehicle by several anchoring members, among which at least two lateral supports engaging on the amounts of the vehicle, as well as at least one strut that bears on the floor.

If such sleepers are generally satisfactory, they have the disadvantage of being relatively heavy and cumbersome, and often complex and expensive to manufacture.

The objects assigned to the invention therefore aim at overcoming the aforementioned drawbacks and at proposing a new, simple and inexpensive dashboard transom manufacturing method which allows for a relief of the cross-member while at the same time retaining a good mechanical behavior of the latter, both vis-à-vis the vibrations that structural forces caused by rolling or possibly by a collision of the vehicle with an obstacle.

The objects assigned to the invention are achieved by means of a method of manufacturing a vehicle dashboard crossmember comprising at least one transverse bar and at least one lateral support arranged to allow the fixing of said crossbar to a vehicle body upright, said method being characterized in that it comprises a step (a) for manufacturing the lateral support in the course of which, in a first material, a plate designed to be fixed on a amount of vehicle body, then it is reported and fixed on said plate a support sleeve which is designed to accommodate the crossbar and which is made of a second material, distinct from the first material and formed by a thermoplastic polymer then a step (b) assembly during which the crossbar is fixed in the support sleeve.

Advantageously, the use of a mixed lateral support structure (using differentiated materials), and more particularly of a bi-material structure, preferably a metallo-pastic structure, makes it possible to lighten the lateral support, and consequently the cross-member as a whole, by the use of the second polymeric material, while maintaining the stability, the robustness, and the programmed deformation capacity in the event of impact of said lateral support, notably by the use of a first appropriate material , such as steel, to form platinum.

In addition, as will be detailed below, the use of a thermoplastic polymer makes it possible to simplify the manufacture of the sleeve of the lateral support as well as the fixing of said sleeve on the transverse bar, making particular possible quick and simple operations forming by molding and / or direct assembly by thermo-welding, which no longer require to involve an adhesive or additional fasteners.

Furthermore, the preferential use of a plate made of a first material which is denser than the second material constituting the sleeve contributes to effectively absorb low frequency vibrations, in particular less than 40 Hz.

Other objects, features and advantages of the invention will appear in more detail on reading the description which follows, and with the aid of the accompanying drawings, provided for purely illustrative and non-limiting purposes, among which:

Figure 1 illustrates, in an overall perspective view, a cross member obtained by the assembly method according to the invention.

Figure 2 illustrates, in a detail view in perspective, the end of the cross bar of the cross member of Figure 1 assembled in the sleeve of the lateral support.

FIG. 3 illustrates, in a vertical sectional view, the detail of the assembly of FIG. 2. FIG. 4 illustrates, according to an overall perspective view, a lateral support according to the invention, as implemented on the assemblies of FIGS. 1 to 3.

The present invention relates to a method of manufacturing a cross member 1 for vehicle dashboard.

As illustrated in FIG. 1, said crossmember 1 comprises at least one transverse bar 2, preferably of circular cross section.

As illustrated in FIG. 1, the transverse bar 2 extends along a director axis (ΥΥ '), preferably substantially rectilinear, and which preferably corresponds to the left-right lateral axis of the vehicle.

Said transverse bar 2 is preferably in the form of a tube, for saving weight and material.

Preferably, to further lighten the structure, the tube forming the crossbar 2 will be made of a composite material based on polymer, for example polypropylene (PP), polyamide (PA) or polyethylene terephthalate (PET) ), or thermosetting resin of epoxy or polyester type, fiber-reinforced, of continuous preference, such as glass fiber, carbon fiber, Keviar®, hemp, or by a mixture of such fibers (for example 80 % of glass fibers and 20% of carbon fibers).

The crossbar 1 also comprises at least one lateral support 3, 3 'arranged to allow the attachment of the crossbar 2 to a vehicle body post (not shown).

The "bodywork upright" is understood in the broadest sense, the lateral support 3, 3 'being able to engage in particular on a pillar "A" door or windshield, or even on the apron that separates the interior of the engine compartment.

According to the invention, the method comprises a step (a) of manufacturing the lateral support 3, 3 'during which is made, in a first material, a plate 4, 4' designed to be fixed on a body post of the vehicle, then it is reported and fixed on said plate 4, 4 'a support sleeve 5, 5' which is designed to accommodate the transverse bar 2 and which is made of a second material, distinct from the first material and formed by a thermoplastic polymer. The compliant process then comprises a step (b) of assembly during which the transverse bar 2 is fixed in the support sleeve 5.

The second material used to form the support sleeve 5 may for example be a polypropylene (PP), and may preferably be loaded with fibers, and more particularly with short fibers, of length of between 1 mm and 4 mm, such as fiberglass, carbon, Kevlar®, hemp, or a mixture of such fibers.

Of course, any other suitable thermoplastic polymer may be considered to form the sleeve 5, in part to lighten the structure of the lateral support 3, and secondly to facilitate the shaping of said sleeve 5 and / or the fixing the lateral support 3 on the transverse bar 2 via said sleeve 5.

Preferably, the cross-member 1 is provided with two lateral supports 3, 3 ', mounted in opposition to each other at each of the axial ends, respectively left and right, of the transverse bar 2, that said lateral supports, respectively left 3 and right 3 ', preferably cap by interlocking.

Of course, the elements and characteristics of the right lateral support 3 'can be deduced mutatis mutandis from the characteristics of the left lateral support 3, to which reference will be made preferably in the following, for convenience of description.

The sleeve 5, 5 'will advantageously have a shape and dimensions substantially conjugate to those of the end of the transverse bar 2 on which said sleeve is fixed.

In particular, said sleeve 5, 5 'may take the form of an annular ring of circular section.

Given the nature of the assembly of the sleeve 5 on the cross bar 2, and for convenience of description, it will be considered that the sleeve 5 and the transverse bar 2 share a same axis director (ΥΥ ').

For convenience of description, the term "axial" means an element oriented or considered along said director axis (ΥΥ '), and "radial" an element oriented or considered perpendicular to said axis director (ΥΥ').

As an indication, the outer diameter of the cross bar 2 (tube) may be of the order of 60 mm to 90 mm, and typically 80 mm. The inner diameter of the sleeve 5 may be of substantially equal value. The thickness E6 of the side wall 6 of the sleeve 5 may be between 2 mm and 3 mm.

Advantageously, the sleeve 5, 5 'offers a radial retaining rim which effectively retains the transverse bar 2 against displacements transverse to its director axis (ΥΥ'), and in particular against front-rear displacements, along the longitudinal axis (XX ') of the vehicle, or vertical, along the vertical axis (ΖΖ') of said vehicle (Figure 1).

The sleeve 5 may advantageously be relatively short, and in particular have an axial length, measured along the directional axis (ΥΥ '), and more particularly an axial length L5 projecting from the plate 4, which will be less than or equal to 50 mm, at 40 mm or even 30 mm, which makes the support 3 particularly light and compact.

In particular, the sleeve 5 will be interrupted preferably axially away from the fasteners 7 for fastening the steering column, as can be seen in FIG.

Preferably, the support sleeve 5 is formed by overmolding on the plate 4.

The use of a thermoplastic polymer, optionally filled with fibers, makes it possible in fact simply and rapidly to manufacture, in large series, the sleeve 5 by injection into a mold, said mold containing the plate 4, or being attached to all or part of of the latter.

Preferably, as is clearly visible in FIG. 3, the support sleeve 5 passes through the thickness E4 of the plate 4 and is provided with a retaining collar 1 0 in which an anchor groove 1 is hollowed radially. 1 whose edges 1 2, 1 3 provide a rebate engagement of said plate 4.

Such a coupling ensures a simple and robust attachment of the support sleeve 5 to the plate 4, since the peripheral retaining collar 1, radially outwardly protruding from the sleeve 5, and preferably formed by a disk, advantageously offers, thanks to at its two edges 1 2, 1 3 placed on either side of the plate 4 and axially gripping said plate in the anchor groove 1 1, a bi-directional axial stop that opposes both the tearing that 'at the depression of the sleeve 5 along the axis director (ΥΥ').

The transverse bar 2 is thus effectively maintained along its director axis (ΥΥ '), in particular against lateral compression forces (approximation) or lateral spacing transmitted along said steering axis (ΥΥ ') by the uprights of the vehicle body.

Preferably, the first constituent material of the plate 4 is a metallic material, such as a steel, an aluminum alloy or a magnesium alloy.

Such materials are indeed easy to form, recyclable, and have good ductility and good resilience, which allows to benefit from a programmed deformation of the plate in particular collision of the vehicle with an obstacle.

Such a choice therefore improves the passive safety of the passenger compartment.

In addition, the use of a first metallic material, denser than the second constituent polymer material of the support sleeve 5, improves the antivibration behavior of the lateral support 3, and therefore the comfort of the occupants of the vehicle.

As an indication, the thickness E4 of the plate 4, and more particularly the thickness of the metal sheet for producing said plate 4, may be substantially between 1, 2 mm and 2.5 mm.

According to a preferred embodiment, the plate 4 is made by stamping.

Such a method is indeed particularly simple and inexpensive to implement, especially since the plate 4 has a relatively uncomplicated shape.

Of course, the plate 4 may be made of any suitable material, preferably denser than the second constituent polymer material of the support sleeve 5.

Thus, according to an alternative embodiment, the plate 4 may be made of a thermosetting resin.

Of course, said resin, and more generally the first constituent material of the plate 4, will be advantageously chosen (e) to withstand the overmolding temperature of the second material.

The shape of the plate 4 may naturally vary depending on particular fixing requirements.

This being the case, according to a variant of preferential arrangement corresponding to that of FIGS. 1 to 4, the plate 4 may have, in projection in a plane normal to the director axis (ΥΥ '), a shape substantially triangular, with a rounded top inside which the sleeve 5 comes to register. Thus, thanks to this spread in "crow's feet" from the sleeve 5, the plate 4 will offer a wide and rigid seat for attachment to the body post, while remaining relatively compact.

Preferably, the support sleeve 5 of thermoplastic polymer material comprises a bottom 14 which forms a stop transverse to the axis (ΥΥ ') of said sleeve 5, against which the crossbar 2, and more particularly the end of said bar 2, comes axially in support.

Such an arrangement advantageously makes it possible to obtain precise, stable and reproducible positioning of the transverse bar 2 in the sleeve 5.

More particularly, it will be possible to fit the transverse bar 2 in the sleeve 5 until the free end of said bar 2 comes into contact with the bottom 14.

In addition, the bottom 14 will provide the crossbar 2 a solid base, which opposes the compression of the transverse 1 along the steering axis (ΥΥ ') and thus the axial approximation of the amounts of the body.

Preferably, for convenience of manufacture and for reasons of robustness, the bottom 14 is formed in one piece with the side wall 6 of the sleeve 5.

As illustrated in FIG. 3, the bottom 14 will preferably be substantially coplanar with the plate 4, and more particularly substantially coplanar with the anchor groove 1 1 and with the platinum portion 4 which is engaged in rebate in said anchor groove 1 1.

Thus, the bottom 14 will contribute to support the retaining flange 10 and to avoid the deformation, and in particular the ovalization, of said retaining flange 10, and more generally of the support sleeve 5, which will improve the holding of said sleeve 5 in platinum 4, and more generally the resistance of said sleeve 5 to crushing.

Furthermore, according to an alternative embodiment, and as shown in Figures 2, 3 and 4, the bottom 14 which cross bar the inside of the sleeve 5 may be pierced with a gripping port 1 5 facilitating handling of the crossbar 1 by a robotic arm.

Said gripping orifice 1 5 may for example take the form of a rectangular cut, of the crevice type, preferably framed by upright edges 1 6 and / or reinforced ribs 1 7 to stiffen the bottom 14 and the orifice 1 5.

For the sake of compactness, upright edges 1 6 and ribs 1 7 are preferably oriented projecting towards the transverse bar 2, so that it can be housed, once the assembly is made, inside the tube forming said cross bar 2, as shown in Figure 3.

According to a preferred embodiment, the assembly of the transverse bar 2 in the support sleeve 5 is performed by laser welding, the material constituting said sleeve 5 being chosen for this purpose to be transparent to the wavelength of the laser beam, and the material constituting the transverse bar 2 being chosen opaque to the same wavelength of the laser beam.

Thus, the laser beam can pass through the transparent side wall 6 of the sleeve 5, but not the opaque material of the bar 2, which will therefore absorb the energy and allow the welding interface to be heated, that is to say, the contact zone between the inner face of the sleeve 5 and the outer face of the bar 2.

Of course, it is conceivable to use other thermal processes for adhering the crossbar 2 to the sleeve, such as for example a mirror welding process (during which is inserted between the sleeve 5 and the bar 2 , a heating blade that is removed once the welding temperature reached).

Preferably, the assembly step (b) is carried out by a welding method and comprises a sub-step (b1) of clamping during which the support sleeve 5 is tightened on the transverse bar 2, during the welding operation, by means of an external constrictor device (not shown), of mandrel or clamp type.

In the case of laser welding, the constrictor device will advantageously be transparent (at least at the wavelength of the laser beam) and may for example be formed by a set of jaws or a PMMA or glass ring.

Advantageously, the constrictor device will temporarily exert, during welding, and especially during or after the heating operation of the welding interface, a centripetal radial compressive force promoting contact, and therefore adhesion and taken between the sleeve 5 and the transverse bar 2. Although it is not excluded that the support sleeve 5 has an uninterrupted side wall around the steering axis (ΥΥ '), said sleeve 5 will preferably, according to an alternative embodiment not shown, formed by a split ring , so as to facilitate its tightening around the transverse bar 2.

The "slot", which improves the deformation capacity, and more particularly the constriction capacity of the sleeve 5, may possibly cover, around the steering axis (ΥΥ '), a relatively large angular (empty) sector of the sleeve, which can for example, to reach 90 degrees (the sleeve 5 then presenting itself as three quarters of a cylinder).

According to a variant of preferential implementation of the process, which may constitute a fully-fledged invention, platinum 4 and transverse bar 2 (initially), which are distinct from each other, are first put in place in a mold. , then the support sleeve 5 is produced by overmoulding by injecting the second material into said mold so as to simultaneously perform the formation of the support sleeve 5, the junction of said support sleeve 5 with said plate 4, and the assembly of the cross bar 2 with said support sleeve 5.

In other words, according to an alternative embodiment which can constitute an invention in its own right, the steps (a) of manufacturing and (b) assembly can be carried out simultaneously by a single overmolding operation, during which the support sleeve 5 is directly overmolded both on the plate 4 and on the transverse bar 2.

Thus, said transverse bar 2, and plate 4, which have been previously formed and then reported and pre-positioned in the mold in the manner of cores, are simultaneously wetted by the second thermoplastic polymer material when it is injected into said mold, which allows to obtain directly, quickly and cheaply, an operational subassembly comprising the crossbar 2 and the lateral support 3 which is integral with said bar 2.

Of course, the invention also relates to a lateral support 3 for a dashboard cross member, said lateral support 3 having a mixed structure comprising on the one hand a plate 4, made of a first material, preferably metal, and designed to to be fixed on a body of the vehicle body, and secondly a support sleeve 5, designed to accommodate the crossbar 2 and secured to said plate, said sleeve of support 5 being made of a second thermoplastic polymer material, distinct from the first material.

The invention also relates to a cross member 1 provided with such a lateral support 3, and preferably two lateral supports 3, 3 'with a mixed structure, preferably interlocked and fixed at each end of its crossbar.

Where appropriate, the left lateral support 3 and the right lateral support 3 'may be substantially symmetrical to each other, with respect to the median plane of the crossmember 1 which crosses the latter perpendicularly to the director axis (ΥΥ ').

The invention naturally relates to a motor vehicle equipped with such a crossbar 1.

Finally, the invention is of course in no way limited to the embodiments described, the skilled person being able to isolate or combine freely between them one or the other of the characteristics described in the foregoing, or substitute them for equivalents where appropriate.

In particular, it would be conceivable, mutatis mutandis, to use the sleeve 5 as a male part (radially internal) and the tube forming the transverse bar 2 as a female part (radially outer), the sleeve 5 being thus nested and attached to the inside the cross tube during assembly, rather than the other way around.

Claims

1. A method of manufacturing a cross member (1) for a vehicle dashboard comprising at least one transverse bar (2) and at least one lateral support (3, 3 ') arranged to allow the fixing of said cross bar (2) to an amount of vehicle body, said method being characterized in that it comprises a step (a) for manufacturing the lateral support during which a platen (4, 4 ') designed to come into a first material is produced to be fixed on a body post of the vehicle, then it is reported and fixed on said plate (4, 4 ') a support sleeve (5, 5') which is designed to accommodate the crossbar (2) and which is made of a second material, distinct from the first material and formed by a thermoplastic polymer, and a step (b) of assembly during which the crossbar (2) is fixed in the support sleeve (5).

2. Method according to claim 1 characterized in that the support sleeve (5) is formed by overmolding on the plate (4).

3. Method according to claim 1 or 2 characterized in that the support sleeve (5) passes through the thickness (E4) of the plate (4) and is provided with a retaining collar (10) in which is hollowed radially an anchor groove (1 1) whose edges (12, 13) provide a rebate engagement of said plate (4).

4. Method according to one of the preceding claims characterized in that the first material constituting the plate (4) is a metallic material, such as a steel, an aluminum alloy or a magnesium alloy.

5. Method according to one of claims 1 to 3 characterized in that the plate (4) is made of a thermosetting resin.

6. Method according to one of the preceding claims characterized in that the support sleeve (5) of thermoplastic polymer material comprises a bottom (14), preferably substantially coplanar with the plate (4), said bottom (14) forming a stop, transverse to the axis (ΥΥ ') of the sleeve (5), against which stop the transverse bar (2) bears axially.

7. Method according to one of the preceding claims characterized in that the assembly of the transverse bar (2) in the support sleeve (5) is performed by laser welding, the constituent material said sleeve (5) being selected for this purpose transparent to the wavelength of the laser beam, and the constituent material of the transverse bar (2) being chosen opaque to the same wavelength of the laser beam.

8. Method according to one of the preceding claims characterized in that the support sleeve (5) is formed by a split ring, and in that the step (b) of assembly is performed by a welding process and comprises a sub-step (b1) of clamping during which said support sleeve (5) is tightened on the transverse bar (2), during the welding operation, by means of an external constrictor device, of mandrel-type or clamp.

9. Process according to one of Claims 1 to 7, characterized in that the platen (4) and the transverse bar (2), which are distinct from one another, are put in place beforehand in a mold. then the support sleeve (5) is formed by overmolding by injecting the second material into said mold so as to simultaneously form the formation of the support sleeve (5), the junction of said support sleeve (5) with said platen ( 4), and the assembly of the transverse bar (2) with said support sleeve (5).

10. Lateral support (3, 3 ') for dashboard cross member, characterized in that said lateral support (3) has a mixed structure comprising on the one hand a plate (4, 4') made of a first material , preferably metal, and adapted to be fixed on a body post of the vehicle, and secondly a support sleeve (5, 5 '), designed to accommodate the transverse bar (2) and secured to said plate ( 4, 4 '), said support sleeve (5, 5') being made of a second thermoplastic polymer material, distinct from the first material.