FR3086630A1 - REAR PART OF MOTOR VEHICLE COMPRISING A SYSTEM FOR PRE-MAINTAINING THE FAIRING UNDER-TRUNK ON THE REAR BEAM - Google Patents

Abstract

The invention relates to a rear part (10) of a motor vehicle comprising a rear beam (12) and a trunk fairing (14) intended to be fixed together with a rear bumper (16) of the motor vehicle, characterized in that it further comprises a pre-holding system (18) configured to maintain the underbody fairing (14) and the rear beam (12) relative to each other in an assembly position allowing the subsequent fixing of the rear bumper (16) with the underbody fairing (14) and the rear beam (12).

Description

REAR PART OF MOTOR VEHICLE COMPRISING A SYSTEM FOR PRE-MAINTAINING THE FAIRING UNDER-TRUNK ON THE REAR BEAM

The present invention relates to a rear part of a motor vehicle comprising a system for pre-holding a fairing fairing on a rear beam of the motor vehicle. The invention also relates to a method for mounting such a rear part incorporating a rear shield.

For the mounting of the rear part of a motor vehicle, a known configuration consists in fixing together the rear beam partly serving to absorb shocks undergone by the motor vehicle, the underbody fairing having the function of protecting the lower part of the motor vehicle at its trunk and the rear bumper forming a portion of the body of the motor vehicle. To do this, the underbody fairing is placed in position vis-à-vis the rear beam which has been previously mounted and is therefore integral with the structure of the motor vehicle. The shield is then positioned against the underbody fairing so as to enclose the underbody fairing between the rear shield and the rear beam. One or more screws are finally put in place to jointly fix the rear beam, the underbody fairing and the rear bumper.

It has been observed that the joint assembly of these three parts is difficult because the positioning in relative position of three parts with respect to each other requires precision and a long assembly time. In particular, the underbody fairing and the rear bumper must be manipulated simultaneously to align them with the rear beam before fixing.

There is therefore a need for a rear part of a motor vehicle, the mounting of which is made easier and faster.

For this, the invention provides a rear part of a motor vehicle comprising a rear beam and a trunk fairing intended to be fixed together with a rear bumper of the motor vehicle, characterized in that it further comprises a pre-installation system. holding configured to maintain the underbody fairing and the rear beam relative to each other in a mounting position allowing subsequent fixing of the rear bumper with the underbody fairing and the rear beam.

A rear part of a vehicle according to the invention has the advantage of allowing a pre-maintenance of the underbody fairing with respect to the rear beam in a satisfactory mounting position while waiting for a rear bumper to be put in place. and fixed to the rear beam and the underbody fairing. The rear beam and the underbody fairing are therefore secured to one another before the fixing of the rear bumper is implemented. The underbody fairing therefore no longer needs to be supported after the interlocking system has been engaged. Thus, the operator has only one piece to handle or put in place at the same time, which saves precision and assembly time.

According to a possible characteristic of the invention, the pre-support system comprises at least one pre-holding tab formed on one of the underbody fairing and the rear beam, said at least one pre-holding tab being configured to retain a portion of the other among the under-boot fairing and the rear beam in at least one pre-holding direction when the under-boot fairing and the rear beam are in the mounting position. In other words, the pre-maintenance system is integrated on the parts requiring to be maintained relative to each other. There is therefore no need to set up or to manipulate an additional mechanism to achieve this pre-maintenance. The simple manipulation of the parts allows the pre-holding system to be engaged.

According to a possible characteristic of the invention, said at least one pre-holding tab is flexible and configured to be elastically deformed under the action of the portion of one of the underbody fairing and the rear beam to allow positioning the underbody fairing and the rear beam in the mounting position. In other words, the pre-holding tabs are formed so as to behave like a return spring allowing, in a first position, the passage of the part to be pre-held under the stress of the pre-holding tab and, in a second position, the maintenance of the part to be maintained.

According to a possible characteristic of the invention, the fixing system comprises at least one flexible pre-holding tab formed on the underbody fairing and at least one fixed pre-holding tab formed on the rear beam, said at least one flexible and fixed pre-hold tab being configured to cooperate together so as to retain the underbody fairing and the rear beam in said at least one pre-maintain direction when they are in the mounting position. The fact of having a fixed pre-holding tab dedicated to the stressing of the flexible pre-holding tab makes it possible to choose a preferred position for the pre-maintenance system. In particular, the pre-maintenance system can be offset from the rear beam fixing area, the underbody fairing and the rear shield so as not to interfere with the mounting or other functions performed by these parts. In addition, the choice of geometry and orientation of the pre-holding system can be made easier with pre-holding tabs dedicated to this function.

According to a possible characteristic of the invention, said flexible premainter tab forms a hook, the fixed pre-holding tab being configured to be positioned inside the hook when the underbody fairing and the rear beam are in the position. mounting. The term hook means that the flexible pre-retaining tab has a free distal end configured to be acted upon by the fixed premainter tab and a proximal end secured to the body of the fairing serving as a support point for the elastic deformation of the flexible pre-hold tab. Advantageously, said fixed pre-holding tab can have a transverse V-shaped profile.

According to a possible characteristic of the invention, the underbody fairing and the rear beam each comprise at least one portion in shape complementarity with each other to index the underbody fairing and the rear beam relative to the other during their assembly. Positioning is thus facilitated and makes it possible to guide the parts towards the engagement of the pre-holding system and therefore the mounting position.

According to a possible characteristic of the invention, the underbody fairing and the rear beam each comprise a fixing hole configured to be arranged facing one another when the pre-maintenance system maintains the underbody fairing and the rear beam in the mounting position.

According to a possible characteristic of the invention, the rear part further comprises:

a rear bumper arranged in contact with the underbody fairing and comprising a fixing hole configured to be arranged facing each of the fixing holes for the underbody fairing and the rear beam, fixing means extending through said holes for fixing the rear bumper, the underbody fairing and the rear beam to fix them together, the underbody fairing being clamped between the rear bumper and the rear beam.

The invention also provides a motor vehicle comprising a rear part as described above.

The invention further provides a method for mounting a rear part of the vehicle as described above, comprising the following steps:

- position the underbody fairing with respect to the rear beam so that the fixing holes for the underbody fairing and the rear beam are aligned,

- place the underbody fairing in contact with the rear beam so as to engage the pre-holding system for the underbody fairing on the rear beam,

- position the rear bumper in relation to the underbody fairing and the rear beam so that the fixing holes for the rear bumper, the underbody fairing and the rear beam are aligned,

- jointly fix the rear bumper, the underbody fairing and the rear beam with the fixing means.

A detailed description is given below of a preferred embodiment of a rear part of a vehicle according to the invention, with reference to the following figures:

FIG. 1 is a perspective view from above of a rear part of a motor vehicle comprising a rear beam, a trunk fairing and a pre-retention system according to the invention,

- Figures 2 and 3 are perspective views of a first and a second detail of the pre-holding system,

FIGS. 4 and 5 are respectively sectional views of the second and first details of the pre-holding system cut at the level of means for fixing a rear bumper and the underbody fairing on the rear beam,

- Figure 6 is a perspective view of an alternative embodiment of the pre-holding system.

The detailed description which follows follows from an XYZ coordinate system conventionally used in automotive design, in which X is the front rear rearward direction directed towards the rear, Y is the transverse direction directed towards the right and Z is the direction vertical directed upwards.

As shown in FIG. 1, a rear part 10 of a motor vehicle comprises a rear beam 12 and a trunk fairing 14 intended to be fixed together with a rear shield 16. In particular, these three parts are each fixed together at the level an attachment zone so that the rear beam 12 and the rear shield 16 enclose the underbody fairing 14 at these attachment zones.

The rear beam 12 extends along the direction Y of the motor vehicle, that is to say between each lateral facade of the motor vehicle. The rear beam 12 has in particular the function of absorbing shocks undergone by the rear part 10 of the motor vehicle and of making the junction between different structural elements of the rear part 10. The rear beam 12 is preferably made of a plastic material. The area for fixing the rear beam 12 to the underbody fairing 14 and to the rear shield 16 is disposed in the lower part of the rear beam 12. In other words, the rear beam 12 is intended to be fixed to the underbody fairing trunk 14 and rear bumper 16 in the lower part of the rear beam 12.

The function of the underbody fairing 14 is to protect the lower part of the motor vehicle at the level of its trunk. The underbody fairing 14 has the general shape of a plate covering a portion of the lower rear part of the motor vehicle. The underbody fairing 14 is preferably made of plastic material. The attachment zone of the under-boot fairing 14 is arranged at a rear portion of the under-boot fairing 14, in particular at a rear end.

The rear shield 16 forms a portion of the body of the motor vehicle. The rear bumper 16 is otherwise called the rear bumper. The attachment area of the rear bumper 16 is arranged under the rear part 10 of the motor vehicle at the bottom of the rear bumper 16.

The rear beam 12, the underbody fairing 14 and the rear shield 16 are fixed through fixing holes 20 formed on the rear beam 12, on the underbody fairing 14 and on the rear shield 16. These fixing holes 20 are formed at the fixing zone of each of the parts. The mounting hole 20 formed on the rear beam is preferably a threaded hole for engaging a screw. The fixing holes 20 formed on the underbody fairing 14 and the rear shield 16 are preferably simple through holes, i.e. without tapping. The fixing holes 20 formed on the underbody fairing 14 and the rear shield 16 are preferably oblong to facilitate their alignment and therefore the fixing of the three parts together.

The rear beam 12, the underbody fairing 14 and the rear shield 16 each comprise at least one fixing hole 20. The fixing holes 20 are positioned on the rear beam 12, the underbody fairing 14 and the rear shield 16 so as to be aligned with one another when the rear beam 12, the underbody fairing 14 and the rear shield 16 are positioned in their final mounting position, as shown in FIG. 1. Preferably , the rear beam 12, the underbody fairing 14 and the rear shield 16 each comprise a plurality of fixing holes 20 to form several distinct fixing zones on each of the parts. The fixing holes 20 are positioned on the rear beam 12, the underbody fairing 14 and the rear shield 16 so as to align three to three the fixing holes 20 at each of the fixing zones.

The rear part 10 further comprises a pre-holding system 18 configured to maintain the underbody fairing 14 and the rear beam 12 relative to each other. In particular, the pre-holding system 18 makes it possible to arrange the underbody fairing 14 and the rear beam 12 in a mounting position. This mounting position is preferably defined as a function of the alignment of fixing holes formed on the underbody fairing 14 and the rear beam 12 for fixing them. This mounting position corresponds to the position of the underbody fairing 14 and of the rear beam 12 allowing the subsequent fixing of the rear shield 16 with the underbody fairing 14 and the rear beam 12.

The pre-holding system 18 thus makes it possible to have the underbody fairing 14 and the rear beam 12 in a satisfactory mounting position while waiting for the rear shield 16 to be put in place and fixed to the rear beam 12 and to the fairing under -cafe 14. Thus, the operator responsible for mounting these elements need only handle one piece at a time when fixing these three pieces together. Indeed, the pre-maintenance system allows, before the final fixing of these three parts, to maintain the underbody fairing 14 in the mounting position without the operator having to support it. The rear shield 16 is then applied against the underbody fairing 14 and the three parts are fixed together. The assembly thus gains in precision which makes it possible to reduce its execution time.

As shown in FIGS. 2 and 3, the pre-hold system 18 comprises a first 22 and a second 24 flexible pre-hold tabs formed on the underbody fairing 14.

The first 22 and second 24 flexible pre-hold tabs are configured to be elastically deformed. In other words, the first 22 and second 24 flexible pre-holding tabs are formed so as to behave like a return spring when they are stressed by a portion of the rear beam 12.

The first 22 and second 24 flexible pre-holding tabs preferably form a hook. By hook is meant that the first 22 and second 24 flexible pre-holding lugs have a free distal end 30 configured to be urged by a portion of the rear beam 12, a proximal end 32 secured to the body of the underbody fairing 14 serving as a fulcrum for the elastic deformation of the flexible pre-holding tabs and an elbow 31 between the distal 30 and proximal 32 ends. This elbow 31 may more generally be a curvature. This hook preferably has a V-shaped transverse profile, as shown in FIGS. 3 to 5. In other words, the first 22 and second 24 flexible pre-holding tabs preferably have two substantially rectilinear sections between which is arranged the elbow 31. The two sides are therefore preferably oriented differently.

A housing 34 is formed inside the hook so as to allow the retention of a part disposed inside the housing.

According to an exemplary embodiment shown in Figure 5, the V-shaped transverse profile can be dimensioned so that the angle a separating each side of the V is about 30.5 °. The distance b separating the top of the V or elbow 31 from the first fixed pre-hold tab 26 is preferably around 18mm. The distance c separating the top of the V or elbow 31 from the free distal end 30 is approximately 18.5 mm. The distance d, taken in a direction perpendicular to the axis of attachment of the screw 44, separating the free distal end 30 from the free end 35 of the first fixed premainter tab 26 is approximately 5.5 mm.

The pre-hold system 18 also comprises a first 26 and a second 28 fixed pre-hold tabs formed on the rear beam 12. The term "fixed" means that the rigidity of the first 26 and second 28 pre-hold tabs fixed support allows them to keep their geometry and their orientation with respect to the body of the rear beam 12 when mounting the underbody fairing 14 on the rear beam 12. To reinforce this rigidity, the first 26 and second 28 legs of fixed pre-hold preferably comprise a stiffener 36 connecting the body of the rear beam 12 to the first 26 and second 28 fixed pre-hold tabs.

The first 26 and second 28 fixed pre-holding tabs are arranged near the fixing holes 20. This improves the alignment of the three parts with each other by having the pre-holding system close to the marks to be aligned, ie the fixing holes 20. In addition, this makes it possible to simplify the design of the rear beam by taking advantage of the fixing zones already produced on the rear beam 12.

The first 22 and a second 24 flexible pre-holding lugs are formed on the underbody fairing 14 so as to be positioned respectively at the level of the first 26 and second 28 fixed pre-holding lugs. In particular, the first 22 and second 24 flexible pre-maintain tabs and the first 26 and second 28 fixed pre-hold tabs are positioned so as to be able to cooperate together when the rear beam 12 and the underbody fairing 14 are placed in the mounting position. In other words, the first 26 and second 28 fixed pre-maintain tabs are configured to be received inside the housings 34 formed by the first 22 and a second 24 flexible pre-hold tabs for engagement of the pre-hold system. 18.

To pre-hold the underbody fairing 14 and the rear beam 12, the flexible and fixed pre-hold tabs are configured to cooperate together so as to retain the underbody fairing 14 and the rear beam 12 along a pre-hold direction when put in the mounting position. The pre-holding direction is preferably merged with the direction Z of the motor vehicle. Alternatively, the pre-hold can be performed in several pre-hold directions. In the latter case, the pre-holding directions are preferably merged respectively with the direction Z as well as the direction X and / or the direction Y of the motor vehicle.

Thus, to engage the pre-holding system 18, the underbody fairing 14 is brought closer to the rear beam 12, in particular in the direction Z, so as to push back the first 22 and second 24 flexible pre-holding tabs by the solicitation of the first 26 and second 28 fixed pre-holding lugs. When the underbody fairing 14 reaches a position close enough to the rear beam 12, the first 22 and second 24 flexible pre-holding lugs are no longer stressed by the underbody fairing 14 and are therefore returned to their initial position, ie

unsolicited, in which they retain the underbody fairing 14 in the mounting position. The interlocking of the pre-holding system 18 is carried out when each fixed pre-holding tab is retained by the corresponding flexible pre-holding tab.

Once the underbody fairing 14 is maintained on the rear beam 12, the operator can put the rear shield 16 in place so that the fixing hole (s) 20 of the rear shield 16 are opposite or aligned with respect to the holes of fixing 20 of the underbody fairing 14 and of the rear beam 12, as shown in FIGS. 1 to 5. The rear shield 16, the underbody fairing 14 and the rear beam 12 are then fixed together with fixing means 44 .

As shown in Figures 4 and 5, the fixing means 44 preferably correspond to a screwed assembly comprising in particular a screw and a washer. The screw is inserted through the simple mounting holes 20 of the trunk fairing 14 and the rear bumper 16 and then engaged inside the tapped fixing hole 20 of the rear beam 12. This encloses the fairing trunk 14 between the rear beam 12 and the rear bumper 16.

The mounting of the rear part of the motor vehicle thus comprises positioning the underbody fairing 14 relative to the rear beam 12 so that the fixing holes 20 of the underbody fairing 14 and the rear beam 12 are aligned. Then, the assembly includes the arrangement of the underbody fairing 14 in contact with the rear beam 12 so as to engage the pre-holding system 18 of the underbody fairing 14 on the rear beam 12. The rear shield 16 is then positioned relative to the underbody fairing 14 and to the rear beam 12 so that the fixing holes 20 of the rear shield 16, of the underbody fairing 14 and of the rear beam 12 are aligned. Finally, the rear bumper 16, the underbody fairing 14 and the rear beam 12 are fixed together with the fixing means 44.

In addition, the underbody fairing 14 and the rear beam 12 may each comprise at least one portion in complementary shape with one another to index the underbody fairing 14 and the rear beam 12 relative to one another. to the other during their assembly. To achieve this indexing, the underbody fairing 14 may include a wall 40 forming a double stop in the direction Y of the motor vehicle. The wall 40 is intended to be received inside a space 42 formed by the rear beam 12. This indexing 5 advantageously makes it possible to facilitate the positioning of the underbody fairing 14 on the rear beam 12, in particular for the alignment of the fixing holes 20 and of the pre-holding system 18.

Alternatively, the pre-hold system 18 can be provided so that the first 22 and second 24 flexible pre-hold tabs 10 are formed on the rear beam 12 and that the first 26 and second 28 pre-hold tabs fixed are formed on the underbody fairing 14.

Claims (11)

1. Rear part (10) of a motor vehicle comprising a rear beam (12) and a trunk fairing (14) intended to be fixed together with a rear shield (16) of the motor vehicle, characterized in that it comprises in addition to a pre-support system (18) configured to maintain the underbody fairing (14) and the rear beam (12) relative to each other in an assembly position allowing the subsequent fixing of the rear bumper (16) with the underbody fairing (14) and the rear beam (12). 2. Rear part (10) according to claim 1, in which the pre-holding system (18) comprises at least one pre-holding tab (22, 24, 26, 28) formed on one of the fairing under -box (14) and the rear beam (12), said at least one pre-holding tab (22, 24, 26, 28) being configured to retain a portion of the other among the underbody fairing (14) and the rear beam (12) in at least one pre-holding direction when the underbody fairing (14) and the rear beam (12) are in the mounting position. 3. Rear part (10) according to claim 2, wherein said at least one pre-holding tab (22, 24) is flexible and configured to be elastically deformed under the action of the portion of one of the fairing trunk (14) and the rear beam (12) to allow the positioning of the trunk fairing (14) and the rear beam (12) in the mounting position. 4. Rear part (10) according to claim 2 or 3, wherein the fixing system comprises at least one flexible pre-holding tab (22, 24) formed on the underbody fairing (14) and at least one tab fixed pre-hold (26, 28) formed on the rear beam (12), said at least one flexible (22, 24) and fixed (26, 28) pre-hold tab being configured to cooperate together so as to retain the underbody fairing (14) and the rear beam (12) in said at least one pre-holding direction when they are in the mounting position. 5. Rear part (10) according to claim 4, in which said flexible pre-holding tab (22, 24) forms a hook, the fixed pre-retaining tab (26, 28) being configured to be positioned inside the hook when the underbody fairing (14) and the rear beam (12) are in the mounting position. 6. Rear part (10) according to any one of the preceding claims, in which the underbody fairing (14) and the rear beam (12) each comprise at least one portion (40, 42) in complementary form. one with the other to index the underbody fairing (14) and the rear beam (12) relative to one another during their assembly. 7. Rear part (10) according to any one of the preceding claims, in which the underbody fairing (14) and the rear beam (12) each include a fixing hole (20) configured to be arranged opposite the one from the other when the pre-support system (18) keeps the under-boot fairing (14) and the rear beam (12) in the mounting position. 8. Rear part (10) according to claim 7, further comprising: - a rear shield (16) disposed in contact with the underbody fairing (14) and comprising a fixing hole (20) configured to be arranged opposite each of the fixing holes (20) of the underbody fairing (14) and the rear beam (12), - fixing means (44) extending through said fixing holes (20) of the rear shield (16), of the underbody fairing (14) and of the rear beam (12) to fix them together, the fairing trunk (14) being sandwiched between the rear bumper (16) and the rear beam (12). 9. Motor vehicle comprising a rear part (10) according to any one of the preceding claims. 10. A method of mounting a rear part (10) of a vehicle according to any one of the preceding claims in combination with the 5 claim 8, comprising the following steps: - position the underbody fairing (14) relative to the rear beam (12) so that the fixing holes (20) of the underbody fairing (14) and the rear beam (12) are aligned, - place the underbody fairing (14) in contact with the rear beam 10 (12) so as to engage the pre-holding system (18) of the underbody fairing (14) on the rear beam (12), - position the rear bumper (16) relative to the underbody fairing (14) and to the rear beam (12) so that the fixing holes (20) of the rear bumper (16), of the underbody fairing (14) 15 and the rear beam (12) are aligned, - jointly fix the rear bumper (16), the underbody fairing (14) and the rear beam (12) with the fixing means (44).