Motor vehicle front face with a cross member level with the main longitudinal members

A motor vehicle front face (1) can be fixed rigidly to the front ends (2) of the main longitudinal members (14) of the motor vehicle. The front face (1) includes:

The present invention relates in general to motor vehicle front faces.

More precisely, the invention relates to a motor vehicle front face that can be fixed rigidly to the front ends of the main longitudinal members of the motor vehicle, the front face being of the type comprising:

at least one cross member;

at least one lock for fastening the bonnet of the motor vehicle, the or each lock being rigidly fixed to the cross member.

BACKGROUND OF THE INVENTION

Front faces have to meet a growing number of requirements, based on regulations or imposed by motor vehicle manufacturers. They must therefore incorporate impact absorbers of various types (medium-speed compatibility impacts, low-speed repairability impacts, pedestrian impacts of the head, hip or leg type), allow easy access to the headlight housing for changing bulbs, be as small as possible, in particular in the Z direction, ensure clearances and flushness, in particular as regards the wings and bonnet of the vehicle, and allow easy adaptation of the front face to the various vehicles which constitute a single construction platform.

Front faces are known which allow some of these demands to be met. Thus, FR-A-2 890 621 discloses a front face of which the upper cross member is slightly lowered so as to accommodate an absorber provided to absorb a hip-type pedestrian impact. However, this front face does not make it possible to meet all of the demands listed above.

SUMMARY OF THE INVENTION

In this context, the object of the invention is to propose a front face having a different structure relative to the state of the art and allowing all the criteria listed above to be met.

For this purpose, the invention relates to a front face of the above-mentioned type, characterised in that the cross member is vertically located substantially level with said front ends of the main longitudinal members.

The cross member may also have one or more of the following features, taken individually or in any technically feasible combination:

the front face comprises at least two headlights, the cross member being vertically located at a level lower than that of the headlights;

the front face comprises at least two absorbers suitable for absorbing so-called medium-speed impacts, these medium-speed impact absorbers being inserted between opposite end portions of the cross member and the front ends of the main longitudinal members;

the medium-speed impact absorbers comprise a block made of a cellular material and a casing in which the block of cellular material engages, the casings being formed by the end portions of the cross member;

the cross member is a component made of an integrally moulded plastics material;

the front face comprises a rigid metal cross beam, said beam having transverse ends inserted between the medium-speed impact absorbers and the front ends of the main longitudinal members;

the cross member is a hybrid component comprising a rigid metal insert and a plastics material overmoulded onto the metal insert;

the front face comprises two headlight housings and two arms to support the headlight housings, said support arms being integral with the cross member;

the support arms are integrally moulded with the cross member;

the support arms are attached to the cross member;

the front face comprises means for mounting the support arms on upper longitudinal members of the vehicle;

the headlight housings are rigidly mounted on the support arms by lower regions, the front face comprising means for mounting upper regions of the headlight housings to the wings of the vehicle;

the front face comprises an absorber provided to absorb leg-type pedestrian impacts, fixed rigidly along a frontal face of the cross member;

the front face comprises a radiator, an upper cassette half, located above the cross member, for fixing the radiator in position and means for fixing the upper cassette half rigidly to the cross member;

the means for rigidly fixing the upper cassette half to the cross member are provided so as to be frangible in hip-type pedestrian collisions on the front of the vehicle;

the front face comprises a lower cassette half, located below the cross member and independent of the upper cassette half, for supporting the radiator, the lower cassette half being integral with the cross member;

the front face comprises means, for rigidly fixing the radiator relative to the lower cassette half, suitable for allowing the radiator to pivot together with the upper cassette half in hip-type pedestrian collisions on the front of the vehicle;

the front face comprises a low channel absorber for absorbing leg-type pedestrian impacts, rigidly fixed to the lower cassette half, at a distance below the cross member; and

the or each lock is vertically located at a distance above the cross member and is rigidly fixed to the cross member by a rigid strut.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the description that follows, the front, rear, longitudinal and transverse directions should be understood relative to the normal direction of movement of the vehicle.

The front face1shown inFIG. 1is an assembly for mounting in one piece on the front ends2of the main longitudinal members4of the motor vehicle. The front ends of the main longitudinal members are situated in a vertical plane halfway up the front of the vehicle, it being possible for said vehicle to also comprise upper longitudinal members (not shown) for stiffening the vehicle wings, and lower longitudinal members situated beneath the main longitudinal members so as to support a pedestrian impact absorber, for example.

The front face1comprises a rigid support structure6, and a plurality of accessories fixed rigidly to this structure. Included among these accessories are in particular the radiator7of the engine cooling circuit (seeFIG. 3), an electric fan assembly suitable for creating forced air convection on contact with the radiator, the front headlights, the front direction indicators, the horn, one or more parking sensors, fog lights, components of the ventilation and air conditioning circuit for the vehicle interior, control sensors for the different airbags of the vehicle and impact absorbers.

All these components are usually mounted on the rigid structure of the front face in the workshop of the front face supplier and said front face, with the pre-mounted accessories, is then mounted on the main longitudinal members of the vehicle at the assembly plant of the motor vehicle constructor.

The rigid structure6comprises a transverse cross member8, a rigid transverse beam10, an upper cassette half12to immobilise the radiator7, a lower cassette half14to support the radiator7and two arms16to support the headlight housings.

The cross member8is an integrally moulded component made of a plastics material. It extends transversally substantially over the entire width of the vehicle. In the vertical direction, it is situated substantially level with the front ends2of the main longitudinal members. It therefore has opposite end portions18arranged longitudinally in the extension of the front ends2of the main longitudinal members.

Considered in a plane perpendicular to the transverse direction the cross member8is of a U-shaped section, open at the rear. Towards the front of the vehicle it has a closed frontal face20. At the top and bottom it is delimited by upper22and lower24closed faces. It is reinforced by integrally moulded struts, for example, arranged in the internal space of the U-shaped cross member, which interconnect the three faces20,22,24of the cross member.

The front face1also comprises different absorbers provided to absorb impacts between the vehicle on which said front face is fitted and another vehicle. The front face comprises in particular absorbers provided to absorb medium-speed impacts on another vehicle, that is, at a relative speed of about 16 km/h. These are known as repairability impacts. The absorbers26can be seen inFIG. 1. Absorbers of this type typically comprise a block made of a cellular material28and a casing30in which the block28engages. The block28is made of aluminium foam for example, or has a honeycomb structure made of aluminium or an aluminium alloy. To obtain good absorber behaviour under impact, these blocks must be arranged in a casing delimiting a housing formed substantially complementary to the block. The deformation of the casing under the effect of the collision makes it possible to control the behaviour of the block.

As shown inFIG. 1, each casing30consists of an end portion18of the cross member. These end portions each comprise a plurality of walls defining the reception housing of a block28.

It can also be seen inFIG. 1that the blocks28are inserted longitudinally between the front ends2of the longitudinal members and the end portions18of the cross member.

The beam10has the function of a bumper beam. It therefore constitutes the structural component of the motor vehicle bumper. Its function is also to stabilise the front portions2of the main longitudinal members of the vehicle.

The beam10is typically in the form of a plate, i.e. a metal plate. It may for example be obtained by stamping. It comprises a central zone32which extends in substantially vertical and transverse plane, and a raised edge34directed towards the rear of the vehicle relative to the central zone. The raised edge34extends over the entire periphery of the central zone32. The beam10is fixed rigidly to the front portions2of the longitudinal members by two opposite transverse ends37. It is fixed to the longitudinal members by any suitable means, for example welding points. The ends37of the beam10are inserted longitudinally between the impact absorbers26and the front ends2of the main longitudinal members.

The impact absorbers26each comprise a mounting plate38for fixing the impact absorber to the beam10. The mounting plate38is fixed rigidly to the block28by welding, for example, or is integral with said block. The mounting plate38is fixed to the corresponding end37by means of fixing bolts, as described below.

The arms16for supporting the headlight housings are of the type described in patent application EP-1 232 932. They are situated, in the vertical direction, at a distance above the cross member8. Typically, they are integrally moulded with the cross member8.

As shown inFIG. 1, the arms16are elongate in shape and extend from an inner end40towards the rear and towards the outside of the vehicle to an outer end42. Each arm16is connected to the cross member8by means of a leg44which is also integral with the cross member8.

The front face also comprises means46for connecting the outer end42of the arm16to one of the upper longitudinal members of the vehicle. The means46typically comprise indexing means of the arm16relative to the vehicle wing and positive fixing means of said arm to the corresponding upper longitudinal member. The indexing means may comprise a pin, for example. The positive fixing means may comprise one or more bolts, for example.

The means46rigidly attach the arm16to said upper longitudinal member.

The upper cassette half12is positioned above the cross member8. It is generally in the shape of a bow which is open downwards, that is, towards the cross member8. It is integrally moulded using a plastics material. It comprises a central transverse portion48and two legs50extending perpendicular to the central portion48from the two opposite ends thereof. The legs50are fixed rigidly to the cross member8by frangible fixing means52.

The cross member8, as shown inFIG. 6, has angles54on its two end portions18. Each angle54has a substantially vertical and transverse flange56integral with the cross member8, and a substantially horizontal flange58extending towards the rear from the vertical flange56. The angles54are integrally moulded with the cross member8. The vertical flange56has two orifices60. The orifices60are placed facing corresponding orifices61and62provided in the mounting plate38and in the end37of the beam corresponding to the angle54respectively. Bolts engage through the orifices60,61,62placed so as to correspond, in such a way that the beam10, the mounting plate38and the end37of the cross member are pressed together and interlock.

The frangible fixing means52comprise sole plates63integral with the free ends of the legs50and applied above the horizontal flanges58of the angles. The sole plates63and the flanges58have orifices64and66arranged so as to correspond. Bolts for fixing the upper cassette half to the cross member engage in the orifices64and66. The legs50extend substantially perpendicular to the sole plates63. The legs50are connected to the sole plates63by a plurality of fins68made of a plastics material. Recesses (not shown) are provided in the sole plate63at the base of the fins68. The sole plates63, the fins68and the recesses form the frangible fixing means52. As detailed below, the means52make it possible for the upper cassette half to be retractable in a hip-type pedestrian collision, in accordance with the principles of applications FR 06 04571 and FR 06 04577 filed by the applicant.

The lower cassette half14is arranged beneath the cross member8. It is in a bow shape similar to that of the upper cassette half. The bow is open at the top, that is, towards the cross member8. The lower cassette half has no direct connection with the upper cassette half. The lower cassette half14is typically integrally moulded with the cross member18. The connection means between the lower cassette half14and the cross member8are not frangible in a pedestrian collision. The lower cassette half14comprises two eyelets69to support and immobilise the lower portion of the radiator. The eyelets69project towards the rear of the vehicle relative to the central transverse portion70of the lower cassette half.

The front face1comprises an absorber72suitable for absorbing leg-type pedestrian impacts. The absorber72is a plastic material foam bar fixed rigidly to the frontal face20of the cross member8. The absorber72extends over most of the transverse length of the cross member8, substantially from one main longitudinal member to the other.

The front face comprises another absorber74, provided to absorb leg-type pedestrian impacts, fixed rigidly to the central portion70of the lower cassette half. This so-called low channel absorber has the form of a substantially horizontal tray made of a plastic material foam. It extends towards the front from the central portion70of the lower cassette half.

The front face also comprises a lock76for fastening the bonnet of the motor vehicle. This lock76is fixed rigidly to the upper face22of the cross member, transversely substantially halfway between the two longitudinal members4, in other words in the centre of the cross member8.

Each of the mounting plates38for fixing the absorbers to the beam10comprises an extension78serving as a stiffener for a vertical leg80of the lower cassette half. The stiffeners78extend downwards from the mounting plate38and are integral therewith. They are laid flat against the legs80, at the rear thereof.

In the assembled state of the front face, shown inFIG. 2, the blocks made of cellular material28engage inside the cross member8, the mounting plate38resting against the vertical flanges56of the angles. The mounting plate38is sandwiched between the flange56and the end37of the beam. The beam10is applied to the open rear face of the cross member8and closes said rear face. The lower14and upper12cassette halves are arranged substantially in the same transverse and vertical plane, above and beneath the cross member8.

As shown inFIG. 2, the upper transverse edge81of the beam projects above the upper face22of the cross member. The lock76rests on said edge81.

The radiator8rests on the eyelets69of the lower cassette half. It comprises spigots projecting downwards, these spigots engaging in the eyelets69. The spigots cooperate with the eyelets69to immobilise the lower portion of the radiator in translation in a horizontal plane.

In addition, the upper cassette half comprises traversing orifices82with vertical axes. Pins engage through the orifices82. Their ends engage in reception housings provided on the upper portion of the radiator. The pins are locked in position relative to the upper cassette half by removable keys. The means for immobilising the radiator relative to the upper and lower cassette halves are known per se and will not be described in more detail here.

By their lower portion100, the headlight housings96of headlights91rest on the arms16and are fixed rigidly to these arms16. Moreover, the front face comprises means, which are not shown, for fixing the upper portions102of the headlight housings96to the vehicle wings104.

In a pedestrian collision, the hip or head of the pedestrian may hit the vehicle bonnet substantially in the region of the upper cassette half12. If the energy transmitted by the impact to the upper cassette half exceeds a predetermined limit, the connection means52break and the cassette half12tilts rearwards and downwards about a transverse axis X1passing substantially through the sole plates63. As shown inFIG. 3, the tilting of the upper cassette half causes the radiator7to tilt about a transverse axis X2passing substantially through the eyelets69. For its part, the lower cassette half does not move. The pivoting of the radiator relative to the lower cassette half is made possible by the fact that the lower portion of the radiator is immobilised simply by the spigots of the radiator engaging in the eyelets69of the lower cassette half. Similarly, a relative pivoting of the radiator7in relation to the upper cassette half12occurs, which is made possible by the fact that the upper cassette half is connected to the radiator by pins which simply engage in housings provided on the radiator.

The front face described above has many advantages.

Since the cross member is vertically located substantially level with the front ends of the main longitudinal members, it is possible to provide the front face with an entirely novel structure, allowing the various legal requirements and the requirements imposed by motor vehicle manufacturers to be met. In particular, the front face no longer comprises an upper cross member passing above the headlight housings96to provide the connection to the upper longitudinal members98of the vehicle. For this reason, access to the headlight housings96to change the bulbs is facilitated considerably.

The cross member does not reduce the air flow for cooling the radiator, as it is incorporated into the impact absorption zone occupied in the known art by the bumper beam.

The upper cassette half is not a structural component, since neither the stability between the main longitudinal members nor that between the upper longitudinal members98and the main longitudinal members is provided by said upper cassette half. The upper cassette half may therefore be made of a less rigid material which is more suitable with regard to the requirements for absorbing pedestrian impacts involving the hips and head.

By contrast, the lower cassette half needs to be stiffened in such a way as to support the radiator, any other cooling components, and the low absorber.

The front face elements, which vary from one vehicle to another within the same constructor range, are brought together on the cross member. These elements are basically the position of the headlight supports, the location of the lock and the location of the connection points to the upper longitudinal members of the wing.

The front face disclosed above may have many variants.

The cross member8may not be an integrally moulded component made of a plastics material, but comprise a metal insert and a plastics material94moulded over the insert (seeFIG. 5). In a variant, the beam10may form the metal insert. In this case, the beam10is placed in front of the medium-speed impact absorbers, which are fixed directly to the front ends of the main longitudinal members.

The portion of the cross member forming a reception casing of the block made of cellular material for the medium-speed impact absorbers may be reinforced by a metal insert.

The support arms of the headlight housings96may not be integral with the cross member, but be components attached to the cross member8.

The lower cassette half14may not be integral with the cross member8, but, like the upper cassette half, be attached to the cross member.

The integral impact absorber of the lower cassette half may be integrally moulded with said lower cassette half. This absorber may also serve to absorb so-called compatibility impacts between vehicles, that is, impacts at a low speed between 2.5 km/h and 4 km/h.

As shown inFIG. 4, the lock76is not necessarily located on the upper face22of the cross member. For stylistic reasons, the lock76may be arranged at a distance above the cross member18and be made integral with said cross member8by a strut90. The strut90may be a rigid metal component. The strut90may also be a plastics material component and may, in a variant, comprise weakening means in such a way that in collisions on the bonnet in the region of the lock76, the strut90can retract in such a way as not to injure the pedestrian.

The front face may comprise not one, but two or more locks for fastening the bonnet, the locks being distributed along the cross member and all being integral with the cross member.