ASSISTED ASSEMBLY OF A MOTOR VEHICLE UNDERBODIES

Abstract

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

Description

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

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

[0002] Certain motor vehicles include a subframe comprising, on the one hand, a central floor having 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 attached two rear longitudinal members, right and left, extending forwards. It should be noted that the assembly consisting of the rear floor and the two rear longitudinal members is frequently called the "rear unit," and that the central floor is generally fixedly attached to a front structural part with which it forms another assembly frequently called the "front unit."

[0003] The assembly of this type of subframe is generally carried out by vertically bringing the front unit closer to the rear unit until the central floor contacts the free parts of the rear side members of the rear unit. The objective is then to achieve contact (or abutment) between the peripheral wall of the central floor and the corresponding central lateral walls of the rear side members (substantially vertical) and between the peripheral rebate of the central floor and the 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 dimensional tolerances in the central floor, rear floor, and rear side members, and variations in the positioning of the rear side members on the front side walls of the rear floor, the gap between the free sections of the rear side members frequently prevents the central floor from being inserted between the two rear side members, and consequently, the aforementioned correct alignment. This necessitates forced assembly, which can lead to deformation and / or damage to the coating, or even requires finding compatible front and rear units for stress-free and damage-free assembly, resulting in wasted time and therefore increased vehicle manufacturing costs.

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

[0006] In particular, it proposes for this purpose a method for assembling a base suitable for equipping a motor vehicle and comprising, on the one hand, a central floor having 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 attached two rear longitudinal members, right and left, extending towards the front.

[0007] This method is characterized by the fact that it includes a step in which the central floor is brought substantially vertically and relatively closer to the rear floor by separating the free parts of each of the rear longitudinal members from each other, until the peripheral rebate is in contact with corresponding lower lateral walls of the rear longitudinal members, then these free parts are no longer separated so that the peripheral wall contacts corresponding central lateral walls of the rear longitudinal members, extended respectively by the lower lateral walls.

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

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

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

[0011] - in the presence of the first option, in its stage, each rod is capable of acting on an inner face of a downward-folded edge of one of the lower lateral walls of the rear longitudinal 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 central lateral walls of the rear longitudinal members, the peripheral rebate of the central floor can be welded to the lower lateral walls of the rear longitudinal members and this peripheral wall to the central lateral walls of the rear longitudinal 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 are respectively fixedly joined two rear longitudinal members, right and left, extending forward, the peripheral rebate being in contact with corresponding lower lateral walls of the rear longitudinal members and the peripheral wall being in contact with corresponding central lateral walls of the rear longitudinal 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 longitudinal members to separate the free parts of each of the rear longitudinal members from each other, during a phase of separating the free parts and of relative bringing the central floor closer to the rear floor.

[0017] The base according to the invention may include other features 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 the lateral sides of the rear longitudinal members and the peripheral wall of the central floor can be welded to the central lateral walls of the rear longitudinal members;

[0019] - it may include a front structural part comprising two sub-parts lateral, right and left, to which are respectively fixedly attached two front longitudinal 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 may include two central longitudinal members, right and left, welded each to one of the rear longitudinal members, to one of the front longitudinal members, and to corresponding lateral portions of the peripheral wall and peripheral rebate of the central floor.

[0021] The invention also proposes 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 box fixedly attached to the underbody so that the central floor defines a cover protecting this battery. Brief description of the figures

[0023] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying drawings (obtained using CAD / CAM (“Computer-Aided Design / Computer-Aided Manufacturing”)), in which:

[0024] [Fig. 1] schematically illustrates, in a perspective view from above, part of an example of an embodiment of a vehicle underbody according to the invention automobile, after assembly of its components by implementing an assembly process according to the invention,

[0025] [Fig.2] schematically illustrates, in a perspective view from above, the base of [Fig.1], at the beginning of its assembly,

[0026] [Fig.3] schematically illustrates, in a perspective view from above, the base of the [Fig.1], at the end of a first intermediate phase of its assembly consisting of positioning its front unit relative to its rear unit by separating the free lateral parts of the rear longitudinal members,

[0027] [Fig.4] schematically illustrates, in a perspective view from below, a part of the base of the [Fig.1], 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 process according to the invention. Detailed description of the invention

[0029] The invention aims in particular to provide an SV underbody for equipping a motor vehicle, and an assisted assembly method for such an SV underbody.

[0030] In what follows, a motor vehicle is considered, by way of non-limiting example, to be a car. However, the invention is not limited to this type of motor vehicle. It relates in fact to any motor vehicle comprising a chassis.

[0031] In figures 1 to 4 the direction X 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 direction Y is intended to be parallel to the transverse direction of the vehicle, which is perpendicular to the longitudinal direction X, and the direction Z is intended to be parallel to the vertical direction of the vehicle, which is perpendicular to the longitudinal direction X and the transverse direction Y.

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

[0033] As illustrated in figures 1 to 3, a subframe SV, according to the invention, comprises at least a central floor PC, a rear floor PR and rear longitudinal 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 should 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 attached, for example by welding, the two rear longitudinal members LRj, right and left, which extend (or project) forward.

[0036] In the preceding and following text, the terms "front" and "rear" refer to the front and rear extremities of the SV underbody (and therefore of the vehicle). Consequently, the front of an element is closer to the front extremity of the SV underbody than to its rear extremity (SV), and the rear of an element is closer to the rear extremity of the SV underbody than to its front extremity (SV).

[0037] Each rear longitudinal member 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 so as to be installed substantially in a horizontal plane XY. It should be noted that each rear longitudinal member LRj also comprises here an upper lateral wall PSLj which extends its central lateral wall PCLj, here substantially perpendicularly so as to be installed substantially in a horizontal plane XY.

[0038] It should also be noted that the assembly consisting of the rear floor PR and the two rear longitudinal members LRj is here referred to as the "rear unit UR".

[0039] It should also be noted that in the example illustrated, but not limited to, in Figures 1 to 3, the central floor PC forms part of another assembly, here referred to as the "front unit UV", along with the front longitudinal members LVj and a front structural part PSV. The front structural part PSV comprises two lateral sub-parts SPj, right (j = 1) and left (j = 2), to which are respectively fixedly attached, for example by welding, the two front longitudinal members LVj, right (j = 1) and left (j = 2), which extend towards the rear and to which are fixedly attached, for example by welding, a portion of the peripheral rebate FP and a portion 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 longitudinal members LRj (and more generally to the rear unit UR) is carried out by means of the implementation of the assembly method according to the invention.

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

[0042] Step 10-40 of the process includes a substep 10 in which the material is brought substantially closer vertically (along the vertical direction Z (arrow F0 of [Fig.2])) and relatively the central floor PC (and more generally the front unit UV) from the rear floor PR (and more generally the rear unit UR) by separating the free portions PLLj of each of the two rear side members LRj (opposite arrows Fl and F2 in [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, "free portion PLLj" means a portion of a rear side member LRj that is not attached to the corresponding lateral sub-section SPj of the front structural section PSV, and is therefore located in front of the latter (PSV).

[0043] Step 10-40 of the process also includes a substep 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 central lateral walls PCLj of the rear longitudinal 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 these parts (PLLj) will 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 the need to search for compatible front UV and rear UR units without the separation, thus avoiding wasted time and increased vehicle manufacturing costs.

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

[0046] For example, in substep 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 spars LRj. It will be understood that in this case, the two arms of the second robot have opposing actions (here, pulls in opposite directions Flet F2 of the transverse direction Y).

[0047] Also, for example, and as illustrated without limitation in [Fig. 4], in substep 10 of step 10-40 each rod TE can be adapted to act on an inner face FI of a downward-folded edge BP of one of the lower lateral walls PILj of the rear side members LRj. In addition, each rod TE is adapted to pass through a lateral notch ELj, which is defined in a corresponding lateral portion of the peripheral rebate FP, during the relative approximation (F0) of the central floor PC to 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 longitudinal members LRj.

[0049] It will also be understood that the cessation of the spacing carried out in substep 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 inner faces of the folded edges BP, then a separation of the two arms of the rear unit UR.

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

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

[0052] It should also be noted, although not shown in Figures 1 to 4, that the SV underbody can subsequently accommodate, beneath its central floor PC, a battery tray housing a rechargeable battery with its control electronics. In this case, the central floor PC acts as a protective cover 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 it to the peripheral rebate FP of the central floor PC.

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

Claims

Demands

1. Method of assembling a subframe (SV) suitable for equipping a motor vehicle and comprising i) a central floor (PC) having 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 attached two rear longitudinal members (LRj), right and left, extending forwards, 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 separating from each other the free parts (PLLj) of each of said rear longitudinal members (LRj), until said peripheral rebate (FP) is in contact with corresponding lower lateral walls (PILj) of said rear longitudinal members (LRj),then we cease to separate the said free parts (PLLj) so that the said peripheral wall (PP) contacts the corresponding central lateral walls (PCLj) of the said rear longitudinal 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 comprising two arms, right and left, each equipped 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 adapted to act on an inner face (FI) of an edge (BP) folded down of one of said lower lateral walls (PILj), and to pass 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. A method according to any 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 stringers (LRj), said peripheral rebate (FP) is welded to said lower lateral walls (PILj) and said peripheral wall (PP) to said lateral central walls (PCLj).

5. Underbody (SV) suitable for equipping a motor vehicle and comprising i) a central floor (PC) having 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 attached two rear longitudinal members (LRj), right and left, extending forward, said peripheral rebate (FP) being in contact with corresponding lower lateral walls (PILj) of said rear longitudinal members (LRj) and said peripheral wall (PP) being in contact with corresponding central lateral walls (PCLj) of said rear longitudinal members (LRj), extended respectively by said lower lateral walls (PILj), characterized in that said peripheral rebate (FP) comprises two lateral portions, right and left, respectively provided with two lateral notches (ELj) adapted to be crossed respectively by two rods (TE),equipping respectively two arms of a robot and adapted to act respectively on internal faces (FI) of two edges (BP) folded downwards of said lower lateral walls (PILj) to separate from each other the free parts (PLLj) of each of said rear longitudinal members (LRj), during a phase of separation of said free parts (PLLj) and relative bringing together of said central floor (PC) and 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) having two lateral sub-parts (SPj), right and left, to which are respectively fixedly attached two front longitudinal members (LVj), right and left, extending towards the rear and to which are attached said peripheral rebate (FP) and said peripheral wall (PP).

8. Base according to claim 7, characterized in that it comprises two central longitudinal members (LCj), right and left, each welded to one of said rear longitudinal members (LRj), to one of said front longitudinal 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 subframe (SV) according to any 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 attached to said underbody (SV) so that said central floor (PC) defines a cover protecting said battery.

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