ASSISTED ASSEMBLY OF A MOTOR VEHICLE UNDERBODY

Abstract

A method for assembling a motor vehicle underbody comprising a central floor comprising a peripheral wall extended by a peripheral rebate, and a rear floor having two front side walls to which two rear side members extending forward are fixedly secured. This method comprises a step (10-40) in which the central floor is brought substantially vertically and relatively closer to the rear floor by moving free parts of each of the rear side members apart from each other, until the peripheral rebate is in contact with corresponding lower side walls of the rear side members, then moving the free parts apart is stopped so that the peripheral wall contacts corresponding central side walls of the rear side members, extended by the lower side walls. Figure 5

Description

Title of the invention: ASSISTED ASSEMBLY OF A MOTOR VEHICLE UNDERBODY Technical field of the invention

[0001] The invention relates to the underbody of motor vehicles, and in particular the assembly of such underbody. State of the art

[0002] Certain motor vehicles comprise a base comprising, on the one hand, a central floor comprising a peripheral wall (substantially vertical) extended by a peripheral rebate (substantially horizontal), and, on the other hand, a rear floor having two front side walls, right and left, to which are respectively fixedly secured two rear side members, right and left, extending forward. It will be noted that the assembly consisting of the rear floor and the two rear side members is frequently called a “rear unit”, and that the central floor is generally fixedly secured to a front structural part with which it constitutes another assembly frequently called a “front unit”.

[0003] The assembly of this type of underbody is generally carried out by vertically bringing the front unit closer to the rear unit until the central floor contacts free parts of the rear side members of the rear unit. The objective is then to achieve contact (or docking) between the peripheral wall of the central floor and corresponding central lateral walls of the rear side members (substantially vertical) and between the peripheral rebate of the central floor and corresponding lower lateral walls of the rear side members (substantially horizontal), before proceeding to weld the central floor to the rear floor (and in particular to its rear side members).

[0004] Due to the dimensional tolerances of the central floor, the rear floor and the rear side members, and the variations in the positioning of the rear side members on the front side walls of the rear floor, it frequently happens that the spacing between the free parts of the rear side members prevents the insertion of the central floor between the two rear side members, and a fortiori the aforementioned correct docking. It is then necessary to carry out a forced assembly, which can lead to deformations and / or damage to the coating, or even to look for compatible front units and rear units for an assembly without stress and without damage, which wastes time and therefore increases the manufacturing costs of the vehicles.

[0005] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0006] It proposes in particular for this purpose a method allowing the assembly of a base suitable for equipping a motor vehicle and comprising, on the one hand, a central floor comprising a peripheral wall extended by a peripheral rebate, and, on the other hand, a rear floor having two front side walls, right and left, to which are respectively fixedly secured two rear side members, right and left, extending towards the front.

[0007] This method is characterized by the fact that it comprises a step in which the central floor is brought substantially vertically and relatively closer to the rear floor by moving the free parts of each of the rear side members apart from each other, until the peripheral rebate is in contact with corresponding lower lateral walls of the rear side members, then moving these free parts apart is stopped so that the peripheral wall contacts corresponding central lateral walls of the rear side members, extended respectively by the lower lateral walls.

[0008] Thanks to the invention, there is no longer any risk of the free parts of the rear side members interfering with the relative translation of the peripheral rebate towards the corresponding lower lateral walls of the rear side members, and therefore there is no longer any risk of deformation and / or damage to the coating, or even of needing to look for compatible front units and rear units without gaps.

[0009] The method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0010] - in its step, we can use a robot comprising two arms, right and left, each equipped with an L-shaped rod to separate the free parts of the rear side members from each other;

[0011] - in the presence of the first option, in its step, each rod is capable of acting on an internal face of a downwardly folded edge of one of the lower lateral walls of the rear side members, and to pass through a lateral notch, defined in a corresponding lateral portion of the peripheral rebate of the central floor, during the relative approach of this central floor to the rear floor;

[0012] - in its stage, after the peripheral wall of the central floor has contacted the corresponding side central walls of the rear side members, the peripheral rebate of the central floor can be welded to the lower side walls of the rear side members and this peripheral wall to the side central walls of the rear side members.

[0013] The invention also proposes a base suitable for equipping a motor vehicle and comprising:

[0014] - a central floor comprising a peripheral wall extended by a rebate peripheral, and

[0015] - a rear floor having two front side walls, right and left, to which two rear side members, right and left, are respectively fixedly secured, extending forward, the peripheral rebate being in contact with corresponding lower lateral walls of the rear side members and the peripheral wall being in contact with corresponding central lateral walls of the rear side members, extended respectively by the lower lateral walls.

[0016] This base is characterized by the fact that the peripheral rebate of its central floor comprises two lateral portions, right and left, respectively provided with two lateral notches suitable for being crossed respectively by two rods, respectively equipping two arms of a robot and suitable for acting respectively on internal faces of two edges folded downwards of the lower lateral walls of the two rear side members to separate from each other free parts of each of the rear side members, during a phase of separation of the free parts and relative approximation of the central floor of the rear floor.

[0017] The base according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0018] - the peripheral rebate of the central floor can be welded to the lower walls side walls of the rear side members and the peripheral wall of the central floor can be welded to the side central walls of the rear side members;

[0019] - it may comprise a front structural part comprising two sub-parts lateral, right and left, to which are respectively fixedly attached two front side members, right and left, extending towards the rear and to which are attached the peripheral rebate and the peripheral wall of the central floor;

[0020] - in the presence of the last option, it can include two central side members, right and left, each welded to one of the rear side members, to one of the front side members, and to corresponding lateral portions of the peripheral wall and peripheral rebate of the central floor.

[0021] The invention also provides a motor vehicle comprising a base of the type presented above.

[0022] For example, this motor vehicle may also include a rechargeable battery installed in a battery tray fixedly secured to the underbody so that the central floor defines a cover protecting this battery. Brief description of the figures

[0023] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the attached drawings (obtained in CAD / CAM (“Computer Aided Design / Computer Aided Drawing”)), in which:

[0024] [Fig.l] schematically illustrates, in a perspective view from above, a part of an exemplary embodiment of a base according to the invention of a vehicle automobile, after assembly of its components by implementing an assembly method according to the invention,

[0025] [Fig.2] schematically illustrates, in a perspective view from above, the base of [Fig.l], at the start of its assembly,

[0026] [Fig.3] schematically illustrates, in a perspective view from above, the base of [Fig.l], at the end of a first intermediate phase of its assembly consisting of positioning its front unit relatively to its rear unit by separating the free lateral parts of the rear side members,

[0027] [Fig.4] schematically illustrates, in a perspective view from below, a part of the base of [Fig.l], in a second intermediate phase of its assembly occurring after the relative positioning of the front unit with respect to the rear unit, and

[0028] [Fig.5] schematically illustrates an example of an algorithm implementing an assembly method according to the invention. Detailed description of the invention

[0029] The invention aims in particular to propose an SV base intended to equip a motor vehicle, and a method for assisted assembly of such an SV base.

[0030] In the following, it is considered, by way of non-limiting example, that the motor vehicle is a car. But the invention is not limited to this type of motor vehicle. It in fact relates to any motor vehicle comprising a base.

[0031] In Figures 1 to 4, the X direction is intended to be parallel to the longitudinal direction of the vehicle (automobile), which is substantially parallel to the lateral (or longitudinal) sides comprising the side doors, the Y direction is intended to be parallel to the transverse direction of the vehicle, which is perpendicular to the longitudinal direction X, and the Z direction is intended to be parallel to the vertical direction of the vehicle, which is perpendicular to the longitudinal directions X and transverse directions Y.

[0032] Figures 1 to 3 schematically illustrate an example of an SV base according to the invention, intended to equip a motor vehicle, once assembled by implementing an assembly method according to the invention.

[0033] As illustrated in Figures 1 to 3, a SV base, according to the invention, comprises at least a central floor PC, a rear floor PR and rear side members LRj right (j = 1) and left (j = 2).

[0034] The central floor PC comprises a peripheral wall PP extended by a peripheral rebate FP (here substantially perpendicular (here in a plane horizontal XY)). It will be noted that the central floor PC also includes an upper wall PS which is extended downwards by the peripheral wall PP and which is here substantially contained in a horizontal plane XY.

[0035] The rear floor PR has two front side walls PLVj, right (j = 1) and left (j = 2), to which are respectively fixedly secured, for example by welding, the two rear side members LRj, right and left, which extend (or project) forward.

[0036] In the above and the following, the concepts of front and rear relate to the front and rear ends of the SV underbody (and therefore of the vehicle). Consequently, the front of an element is closer to the front end of the SV underbody than to the rear end of the latter (SV), and the rear of an element is closer to the rear end of the SV underbody than to the front end of the latter (SV).

[0037] Each rear spar LRj comprises a central lateral wall PCLj, here installed substantially in a vertical and longitudinal plane ZX, and a lower lateral wall PILj extending this central lateral wall PCLj here substantially perpendicularly in order to be installed substantially in a horizontal plane XY. It will be noted that each rear spar LRj also comprises here a upper lateral wall PSLj which extends its central lateral wall PCLj, here substantially perpendicularly in order to be installed substantially in a horizontal plane XY.

[0038] It will also be noted that the assembly consisting of the rear floor PR and the two rear side members LRj is here called “rear unit UR”.

[0039] It will also be noted that in the example illustrated non-limitingly in Figures 1 to 3, the central floor PC is part, with front side members LVj and a front structural part PSV, of another assembly here called “front unit UV”. The front structural part PSV comprises two lateral sub-parts SPj, right (j = 1) and left (j = 2), to which are respectively fixedly secured, for example by welding, the two front side members LVj, right (j = 1) and left (j = 2), which extend towards the rear and to which are fixedly secured, for example by welding, a part of the peripheral rebate FP and a part of the peripheral wall PP of the central floor PC.

[0040] The assembly of the central floor PC (and more generally of the front unit UV) to the rear floor PR and to the rear side members LRj (and more generally to the rear unit UR) is carried out by implementing the assembly method according to the invention.

[0041] As illustrated non-limitingly in [Fig. 5], the (assembly) method, according to the invention, comprises a step 10-40 which is implemented each time that a front unit UV must be fixedly secured to a rear unit UR (relatively).

[0042] Step 10-40 of the method comprises a sub-step 10 in which the following are brought together substantially vertically (along the vertical direction Z (arrow F0 of [Fig.2])): and relatively the central floor PC (and more generally the front unit UV) of the rear floor PR (and more generally of the rear unit UR) by separating from each other the free parts PLLj of each of the two rear side members LRj (opposite arrows Fl and F2 of [Fig.4]) until the peripheral rebate FP of the central floor PC is in contact with the corresponding lower lateral walls PILj of the rear side members LRj. Here, the term "free part PLLj" means a part of a rear side member LRj which is not attached to the corresponding lateral sub-part SPj of the front structural part PSV, and therefore which is located in front of the latter (PSV).

[0043] Step 10-40 of the method also comprises a sub-step 20 in which the free parts PLLj are no longer separated so that the peripheral wall PP of the central floor PC contacts the corresponding lateral central walls PCLj of the rear side members LRj (which are extended respectively by the lower lateral walls PILj).

[0044] It will be understood that by separating the free parts PLLj from each other there is no longer any risk that the latter (PLLj) interfere with the relative translation (here vertical (arrow F0)) of the peripheral rebate FP towards the corresponding lower lateral walls PILj of the rear side members LRj. Consequently, there is no longer any risk of deformation and / or damage to the coating, or even of needing to look for compatible front unit UV and rear unit UR without spacing, which makes it possible to avoid wasting time and increasing the manufacturing costs of the vehicles.

[0045] It will be noted that the relative movement (arrow F0) of the front unit UV with respect to the rear unit UR can be done automatically by means of a first robot (not shown) on an assembly line. But it could be carried out by at least one operator (possibly assisted by an exoskeleton).

[0046] For example, in sub-step 10 of step 10-40, a second robot (not shown) can be used, comprising two arms, right and left, each equipped with an L-shaped rod TE (see [Fig.4]) to separate the free parts PLLj of the rear side members LRj from each other. It will be understood that in this case, the two arms of the second robot have opposite actions (here tractions in opposite directions Flet F2 of the transverse direction Y).

[0047] Also for example, and as illustrated non-limitingly in [Fig.4], in sub-step 10 of step 10-40 each rod TE may be capable of acting on an internal face FI of an edge BP folded downwards of one of the lower lateral walls PILj of the rear side members LRj. In addition, each rod TE is capable of passing through a lateral notch ELj, which is defined in a corresponding lateral portion of the peripheral rebate FP, during the relative approach (F0) of the central floor PC of the rear floor PR.

[0048] It will be understood that thanks to these lateral notches ELj defined in the peripheral rebate FP at the transverse locations where the rods TE are positioned, the relative translation of the central floor PC towards the rear floor PR is not interrupted by the temporary presence of the rods TE, and therefore in sub-step 10 the peripheral rebate FP of the central floor PC can come into contact with the corresponding lower lateral walls PILj of the rear side members LRj.

[0049] It will also be understood that the cessation of the separation carried out in sub-step 20 results here from an action of the two arms of the second robot in directions opposite to the previous ones (i.e. oriented towards each other) in order to separate the two rods from the internal faces of the folded edges BP, then a moving away of the two arms of the rear unit UR.

[0050] Also for example, and as illustrated non-limitingly in [Fig.5], step 10-40 can also comprise a sub-step 30 in which, after the peripheral wall PP has contacted the corresponding lateral central walls PCLj of the rear side members LRj, the peripheral rebate FP can be welded to the lateral lower walls PILj and the peripheral wall PP to the lateral central walls PCLj.

[0051] Also for example, and as illustrated non-limitingly in [Fig.5], step 10-40 can also comprise a sub-step 40 in which, after the welding carried out in sub-step 30, two central side members LCj, right (j = 1) and left (j = 2), can be welded respectively on lateral portions of the central floor PC (and in particular its peripheral wall PP and peripheral rebate FP) and on the rear side members LRj and front side members LVj, so as to reinforce the strength of the underbody SV. These central side members LCj are illustrated in Figures 1 and 3.

[0052] It will also be noted, although this does not appear in Figures 1 to 4, that the SV base can subsequently receive, under its central floor PC, a battery tray housing a rechargeable battery with its control electronics. In this case, the central floor PC provides a protective cover function for the battery tray, and the battery tray, the rechargeable battery with its control electronics, and the central floor PC constitute a battery assembly (or pack) EB. This cover thus protects at least the rechargeable battery.

[0053] Preferably, the battery tray is fixedly secured by screwing to the peripheral rebate FP of the central floor PC.

[0054] Also for example, the rechargeable battery may comprise at least one cellular module comprising at least two electrical energy storage cells. Here, the term "electrical energy storage cell" means a rechargeable and possibly electrochemical cell (for example of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type).

Claims

Claims

1. Method for assembling a subframe (SV) suitable for equipping a motor vehicle and comprising i) a central floor (PC) comprising a peripheral wall (PP) extended by a peripheral rebate (FP), and ii) a rear floor (PR) having two front side walls (PLVj), right and left, to which are respectively fixedly secured two rear side members (LRj), right and left, extending forward, characterized in that it comprises a step (10-40) in which said central floor (PC) is brought substantially vertically and relatively closer to said rear floor (PR) by moving the free parts (PLLj) of each of said rear side members (LRj) apart from each other, until said peripheral rebate (FP) is in contact with corresponding lower side walls (PILj) of said rear side members (LRj),then the said free parts (PLLj) are stopped being separated so that the said peripheral wall (PP) contacts the corresponding central lateral walls (PCLj) of the said rear side members (LRj), extended respectively by the said lower lateral walls (PILj).,

2. Method according to claim 1, characterized in that in said step (10-40) a robot is used comprising two arms, right and left, each provided with an L-shaped rod (TE) to separate said free parts (PLLj) from each other.

3. Method according to claim 2, characterized in that in said step (10-40) each rod (TE) is capable of acting on an internal face (FI) of an edge (BP) folded downwards of one of said lower lateral walls (PILj), and of passing through a lateral notch (ELj), defined in a corresponding lateral portion of said peripheral rebate (FP), during the relative approach of said central floor (PC) to said rear floor (PR).

4. Method according to one of claims 1 to 3, characterized in that in said step (10-40), after said peripheral wall (PP) has contacted said corresponding lateral central walls (PCLj) of said rear side members (LRj), said peripheral rebate (FP) is welded to said lower lateral walls (PILj) and said peripheral wall (PP) is welded to said lateral central walls (PCLj).

5. Base (SV) suitable for equipping a motor vehicle and comprising i) a central floor (PC) comprising a wall peripheral (PP) extended by a peripheral rebate (FP), and ii) a rear floor (PR) having two front side walls (PLVj), right and left, to which are respectively fixedly secured two rear side members (LRj), right and left, extending forward, said peripheral rebate (FP) being in contact with corresponding lower side walls (PILj) of said rear side members (LRj) and said peripheral wall (PP) being in contact with corresponding central side walls (PCLj) of said rear side members (LRj), extended respectively by said lower side walls (PILj), characterized in that said peripheral rebate (FP) comprises two lateral portions, right and left, respectively provided with two lateral notches (ELj) suitable for being crossed respectively by two rods (TE),respectively equipping two arms of a robot and suitable for acting respectively on internal faces (FI) of two edges (BP) folded downwards of said lower lateral walls (PILj) to separate from each other free parts (PLLj) of each of said rear side members (LRj), during a phase of separation of said free parts (PLLj) and relative approach of said central floor (PC) to said rear floor (PR).,

6. Base according to claim 5, characterized in that said peripheral rebate (FP) is welded to said lower lateral walls (PILj) and said peripheral wall (PP) is welded to said central lateral walls (PCLj).

7. Base according to claim 5 or 6, characterized in that it comprises a front structural part (PSV) comprising two lateral sub-parts (SPj), right and left, to which are respectively fixedly secured two front side members (LVj), right and left, extending towards the rear and to which are secured said peripheral rebate (FP) and said peripheral wall (PP).

8. Base according to claim 7, characterized in that it comprises two central side members (LCj), right and left, each welded to one of said rear side members (LRj), to one of said front side members (LVj), and to corresponding lateral portions of said peripheral wall (PP) and peripheral rebate (FP).

9. Motor vehicle, characterized in that it comprises a base (SV) according to one of claims 5 to 8.

10. Vehicle according to claim 9, characterized in that it comprises a rechargeable battery installed in a battery tray fixedly secured to said underbody (SV) so that said central floor (PC) defines a cover protecting said battery.

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