Device for assisting in folding by folding a closing flap of one end of a U-shaped section sheet metal part

Abstract

The invention relates to a device (20) for assisting in folding a closing flap (13) of a longitudinal end of a U-shaped sheet metal part (10) of the type comprising a sole (11) and two lateral panels (12) folded down opposite the latter, said flap being attached laterally to two flaps (14) folded down opposite the latter, said device comprising a spacing tool (21) comprising a head (23) provided with two lateral guide faces and mounted to move in translation in a direction perpendicular to the transverse folding axis of said flap between a retracted position and a deployed position where said guide faces are each able to cooperate with the inner face of a said corresponding flap during the folding of said flap to elastically and reversibly increase the spacing between these flaps so as to ensure that they cover an end portion of said lateral panels from the outside.Figure to be published with the abstract: Fig. 7.

Description

Title of the invention: Device for assisting in folding by folding a closing flap of one end of a sheet metal part with a U-shaped section Technical field

[0001] The present invention relates generally to manufacturing processes by cutting and folding a sheet metal part, in particular for a motor vehicle.

[0002] It relates in particular to a device for assisting in folding by folding a closing flap of one end of a sheet metal part with a U-shaped section, as well as a method for manufacturing such a part implementing this device. Prior art

[0003] The manufacturing process, from a sheet metal side, of a part such as for example a motor vehicle part, comprises a succession of steps.

[0004] Generally, such a manufacturing method comprises a first stamping step, a second trimming step and at least one folding step.

[0005] Each folding step is carried out by means of one or more folding tools each comprising in a conventional manner a folding blade which is mounted in translation between a retracted position and a deployed position where said blade cooperates with the portion of the sheet to be folded.

[0006] Certain sheet metal parts require several bending steps, in particular when the sheet metal comprises a plurality of portions to be bent which each extend in a distinct plane and which are each angularly offset.

[0007] This is the case for a rear seat cross member with a U-shaped section intended to be fixedly installed on the rear floor of a vehicle, extending between a side member and a central exhaust tunnel.

[0008] Such a part comprises a central sole, two lateral panels extending on either side of this sole and folded down in relation to the latter, as well as a closing flap attached to a longitudinal end of said sole and folded down in relation to the latter so as to close the corresponding longitudinal end of the part.

[0009] This flap is further attached laterally to two side flaps which are also folded down and each fixed by electric welding points (EWS) to an end portion of a corresponding side panel.

[0010] Conventionally, the side flaps and the shutter are folded before the two side panels are folded so that the latter cover the outside these side flaps.

[0011] In certain cases and for example to ensure better mechanical strength of such a part, it may be advantageous to fold the two side panels as well as the two side flaps before folding the shutter, so that these two side flaps cover an end portion of these side panels from the outside.

[0012] Such a manufacturing process thus makes it possible, in the event of a lateral impact on the closing flap of a floor crossmember produced in this way, to ensure that the forces experienced by this flap are absorbed by the two corresponding end edges of the side panels, so as to obtain better resistance to deformation of this crossmember.

[0013] Unfortunately, such a manufacturing process presents, in particular due to a certain elasticity of the sheet metal and the tolerances concerning the folding angles, a risk of interference between the end edges of the side flaps and those of the side panels during the folding operation of this flap.

[0014] It is easily understood that this type of interference can lead to deterioration of the production tooling and / or that of the sheet metal part. Statement of the invention

[0015] The present invention therefore aims to improve the situation.

[0016] To this end, it proposes a device for assisting in folding a closing flap of a longitudinal end of a U-shaped sheet metal part of the type comprising a central sole and two lateral panels extending on either side of this sole and folded down opposite the latter, said closing flap being attached to a longitudinal end of said sole and intended to be folded down opposite the latter so as to close the corresponding longitudinal end of said part, said flap being further attached laterally to two lateral flaps folded down opposite the latter and intended to cover an end portion of the outer face of said lateral panels; characterized in that said device comprises a spacing tool comprising a head provided with two lateral guide faces and mounted so as to move in translation in a direction perpendicular to the transverse folding axis of said flap between a retracted position in which it cannot interact with said flap or with said lateral flaps when folding this flap, and a deployed position where said guide faces are each able to cooperate with the inner face of a said corresponding lateral flap when folding said flap to elastically and reversibly increase the spacing between these flaps so as to ensure that the latter cover an end portion of said lateral panels from the outside.

[0017] The invention thus makes it possible to avoid any risk of interference between the end edges of the side flaps and those of the side panels during the folding operation of this flap.

[0018] According to preferred characteristics of said device according to the invention: - said lateral guide faces extend at an angle relative to the median vertical longitudinal plane of said part and so that their spacing increases according to the direction of folding of said flap; - said lateral guide faces are arranged symmetrically to one another with respect to the median vertical longitudinal plane of said part; - said head is made of a single block; - said tool comprises a mast carrying said head at one of its ends; and / or - said device also comprises actuating means capable of ensuring the translational movement of said tool and comprising a pneumatic or hydraulic cylinder acting on said mast.

[0019] The invention also relates, in a second aspect, to a method of manufacturing, from a sheet metal side, a part with a U-shaped section comprising a central sole, two lateral panels extending on either side of this sole and folded down opposite the latter, as well as a closing flap attached to a longitudinal end of said sole and folded down opposite the latter so as to close the corresponding longitudinal end of said part, said flap being further attached laterally to two lateral flaps folded down opposite the latter and covering an end portion of the outer face of said lateral panels, said method successively comprising: - a step of peripheral trimming of said sheet metal side to delimit around said sole said side panels, said flap and said flaps, - folding steps consisting of folding said side flaps opposite said flap and folding said side panels opposite said sole, and - a folding step consisting of folding said flap opposite said sole so as to close said longitudinal end of said part; characterized in that said step of folding said shutter implements such a folding assistance device.

[0020] According to preferred characteristics of said method according to the invention: - this also includes an opening step consisting of creating openings in said sole and / or said side panels by cutting; - this also comprises, after said folding steps, a step of producing electrical welding points between each said side flap and the respective end portion of a said corresponding side panel; and / or - this also comprises, before said folding steps, a step of stamping said sheet metal side in order to form stiffening ribs on said sole and / or said side panels. Brief description of the drawings

[0021] The description of the invention will now be continued by the detailed description of an exemplary embodiment, given below for illustrative but non-limiting purposes, with reference to the appended drawings, in which: - [Fig.l], [Fig.2], [Fig.3], [Fig.4], [Fig.5] and [Fig.6] illustrate the different stages of the manufacturing process, using the device according to the invention, of a sheet metal part with a U-shaped section and one longitudinal end of which is closed by a closing flap; - [Fig.7] is a perspective view illustrating a first phase of the folding step of the closing flap implementing the device according to the invention; - [Fig.8] represents a horizontal section view of the head of the spreading tool of the device according to the invention; - [Fig.9] is an elevational view illustrating a second intermediate phase of the folding step of the closing flap; and - [Fig. 10] represents an elevation view illustrating the last phase of the folding step of the closing flap. Description of the embodiments

[0022] Figures 1 to 6 illustrate the different stages of the manufacturing process, from a sheet metal flank T of geometric shape (for example, rectangular), of a sheet metal part 10 shown in [Fig.6] and consisting in this case of a rear seat crossmember for a motor vehicle.

[0023] We define with respect to this sheet side T in the plane state of [Fig.l], an orthogonal reference XYZ comprising three axes perpendicular two by two, namely: - an X axis corresponding to the longitudinal direction of the part 10 to be produced; - a Y axis, defining a transverse direction and which with the X axis defines a horizontal plane XY parallel to that of the sheet side T, and - a Z axis, defining a vertical direction, perpendicular to this sheet side T as well as to the horizontal XY plane.

[0024] In the remainder of the description and with reference to the reference defined above, the terms “longitudinal” or “longitudinally” will refer to a direction parallel to the X axis, the terms “transverse” or “transversely” will refer to a direction parallel to the Y axis, and the terms “vertical” or “vertically” will refer to a direction parallel to the Z axis.

[0025] With reference to [Fig.6] showing the sheet metal part 10 in its final conformation, this part 10 has a U-shaped section and comprises a central sole 11 as well as two side panels 12 extending on either side of this sole 11 and folded down opposite the latter.

[0026] The part 10 also comprises a closing flap 13 attached to one of the longitudinal ends of this sole 11 and folded opposite the latter so as to close the corresponding longitudinal end of this part 10.

[0027] Two side flaps 14 attached laterally to this flap 13 are further folded down with respect to the latter and cover an end portion of the outer face of the side panels 12 to which they are welded.

[0028] Part 10 further comprises: - three tabs 15, 16 extending the edges opposite the sole of the side panels 12 and the flap 13 respectively, these tabs 15, 16 being folded outwards with respect to the latter so as to allow the fixing of the part 10 on another sheet metal part such as a rear floor of a motor vehicle; and - three tabs 17 extending respectively the second end of the sole 11 and the corresponding ends of the side panels 12, these tabs 17 being folded outwards with respect to these elements 11, 12 so as to allow the fixing of the part 10 on another sheet metal part such as a central exhaust tunnel of a motor vehicle.

[0029] This part 10 finally has several stamped stiffening ribs 18 provided on the sole 11 and / or the side panels 12, as well as a plurality of openings 19 provided in the sole 11 and / or the side panels 12.

[0030] With reference to [Fig. 1], the first step of the manufacturing process of the part 10 is a step of stamping the sheet metal flank T in order to form the stiffening ribs 18, this step being carried out for example by means of a conventional stamping tool (not shown) comprising a die, a punch and possibly one or more blank holders.

[0031] The second step of this process, illustrated by [Fig.2], is a step of peripheral trimming of the sheet metal flank T, namely the cutting and removal of the peripheral portion of the latter to delimit around the sole 11 the lateral panels 12, the flap 13, the flaps 14, and the tabs 15, 16, 17.

[0032] This step is for example carried out by means of a conventional cutting tool or punch (not shown) comprising, on the one hand, a crown-shaped die, which is provided with a raised and profiled stop whose shape corresponds to the peripheral zone of the sheet flank T and, on the other hand, a member acting as a punch, provided with vertical cutting elements capable of cooperating in the manner of shears, under the action of a press, with the outer edges of the raised and profiled stop of the die to cut the peripheral zone of this sheet flank.

[0033] The third step of this process, illustrated by [Fig.3], is a first step of folding consisting of folding the flaps 14 opposite the flap 13, the tabs 15 opposite the side panels 12, the tab 16 opposite the flap 13, as well as the tabs 17 opposite the sole 11 or the side panels 12.

[0034] This step is for example carried out by means of several folding tools provided with a folding blade and each mounted in translation in a vertical direction (i.e. perpendicular to the sheet side T) between a retracted position and a deployed position where said blade cooperates with a flap 14 or a tab 15, 16, 17 so as to cause it to be folded down by folding around a transverse axis (for the tabs 15 and 17) or longitudinal axis (for the flaps 14 and the tabs 16).

[0035] The fourth step of this process, illustrated by [Fig.4], is a second folding step consisting of folding the side panels 12 opposite the sole 11, this step being for example carried out by means of two folding tools similar to those of the first folding step but each mounted in translation in a vertical direction between a retracted position and a deployed position where said blade cooperates with a side panel 12 so as to cause it to be folded down by folding around a longitudinal axis.

[0036] The fifth step of this process, illustrated by [Fig.5], is a third folding step consisting of folding the flap 13 opposite the sole 11 so as to close the corresponding longitudinal end of the part 10.

[0037] This step is for example carried out in particular by means of a folding tool similar to those of the first folding step and mounted in translation in a vertical direction between a retracted position and a deployed extended position where said blade cooperates with this flap 13 so as to cause it to be folded down by folding around a transverse axis. The invention relating to it more particularly, this step will be described in more detail below with reference to FIGS. 7 to 10.

[0038] The sixth step of this process, illustrated by [Fig.6], is a cutting step consisting of producing by cutting the openings 19 in the sole 11 and / or the side panels 12. This step is for example carried out using several conventional cutting tools or punches similar to those used during the second cutting step.

[0039] A final step, not illustrated, finally consists of making electrical welding points between an end portion of each side panel 12 and a corresponding side flap 14, so as to rigidly secure the closing flap 13 to these two side panels 12.

[0040] Let us now return to the step of folding the flap 13 with respect to the sole 11, with reference to figures 7 to 10.

[0041] As illustrated by these figures, this step involves a device 20 according to the invention for assisting in folding this flap 13, comprising a tool spacer 21 provided with a vertical mast 22 carrying at its upper end a head 23.

[0042] This head 23 is provided with two lateral guide faces 23A each intended to cooperate with the inner face of a corresponding lateral flap 14 when folding the closing flap 13.

[0043] As is clearly visible in [Fig.8], the two lateral guide faces 23A of the head 23 extend at an angle relative to the median vertical longitudinal plane of the part 10, and so that their spacing increases according to the direction of folding by folding the closing flap 13.

[0044] Still with reference to [Fig.8], these two lateral guide faces 23A are preferably arranged symmetrically to one another with respect to the median vertical longitudinal plane of the part 10.

[0045] The head 23 is advantageously made up of a single block having a flared profile in horizontal section and preferably made from a metallic material having a hardness greater than that of the sheet constituting the part 10 (for example, a carbon steel of grade Z160).

[0046] The tool 21 is mounted in translation in a vertical direction, perpendicular to the transverse folding axis of the flap 13, between: - a retracted position illustrated by [Fig. 10] in which it cannot interact with the flap 13 or with the side flaps 14 when folding this closing flap 13; and - a deployed position illustrated by figures 7 to 9 where the guide faces 23A of its spreading head 23 are each able to cooperate with the inner face of a corresponding lateral flap 14 when folding this closing flap 13 to elastically and reversibly increase the spacing between these flaps 14 so that the latter cover an end portion of the outer face of the lateral panels 12.

[0047] In order to ensure the translational movement of the tool 21, the device 20 also comprises actuating means not shown and comprising for example a pneumatic or hydraulic cylinder of the double-acting type, comprising a cylindrical body as well as a rod carrying at one of its ends a piston (mounted mobile with longitudinal sliding in the body and the second end of which protrudes from this body and is rigidly coupled to the mast 22 of the tool 21.

[0048] The two chambers of the cylinder separated by the piston are each fluidically connected by means of a respective pipe to an electro-distributor managing the operation of the cylinder and itself connected to a compressed air supply circuit.

[0049] When the step of folding the flap 13 starts, the spreading tool 21 occupies its raised extended position so that the internal faces of the two side flaps 14 will come at a time into contact with the two guide faces 23A of the spreading head 23 of this tool 21 as illustrated by [Fig.7].

[0050] Continuing this folding of the flap 13 will then cause a slight elastically reversible increase in the spacing between the side flaps 14, making it possible to avoid any risk of interference between the end edges of these flaps 14 and those of the side panels 12 and to ensure that these same flaps 14 cover an end portion of these side panels 12 from the outside (see [Fig.9]).

[0051] As soon as the flaps 14 begin to cover these side panels 12, the spacing tool 21 is no longer useful and it is then automatically returned to the low retracted rest position so as not to interfere with the flap 13 at the end of the folding step 500 as illustrated by [Fig.9].

[0052] No longer being acted upon by this spacing tool 21, the flaps 14 thus return to their folded position with respect to the shutter 13, so as to come to rest almost flat against the first end of the side panels 12.

[0053] Numerous variant embodiments are conceivable and it is recalled in this regard that the present invention is not limited to the embodiments described and shown, but also encompasses all variant embodiments within the reach of those skilled in the art.

Claims

Claims

1. Device (20) for assisting in folding a closing flap (13) of a longitudinal end of a U-shaped sheet metal part (10) of the type comprising a central sole (11) and two lateral panels (12) extending on either side of this sole (11) and folded down opposite the latter, said closing flap (13) being attached to a longitudinal end of said sole (11) and intended to be folded down opposite the latter so as to close the corresponding longitudinal end of said part (10), said flap (13) being further attached laterally to two lateral flaps (14) folded down opposite the latter and intended to cover an end portion of the outer face of said lateral panels (12);characterized in that said device (20) comprises a spacing tool (21) comprising a head (23) provided with two lateral guide faces (23A) and mounted movable in translation in a direction perpendicular to the transverse folding axis of said flap (13) between a retracted position in which it cannot interact with said flap (13) or with said lateral flaps (14) during the folding of this flap (13), and a deployed position where said guide faces (23A) are each able to cooperate with the inner face of a said corresponding lateral flap (14) during the folding of said flap (13) to elastically reversibly increase the spacing between these flaps (14) so ​​as to ensure that the latter cover from the outside an end portion of said lateral panels (12).;

2. Assistance device (20) according to claim 1, characterized in that said lateral guide faces (23A) extend at an angle relative to the median vertical longitudinal plane of said part (10) and so that their spacing increases according to the direction of folding by folding of said flap (13).

3. Assistance device (20) according to one of claims 1 or 2, characterized in that said lateral guide faces (23A) are arranged symmetrically to one another with respect to the median vertical longitudinal plane of said part (10).

4. Assistance device (20) according to one of claims 1 to 3, characterized in that said head (23) consists of a single block.

5. Assistance device (20) according to one of claims 1 to 4, ca- characterized in that said tool (21) comprises a mast (22) carrying at one of its ends said head (23).

6. Assistance device (20) according to claim 5, characterized in that it also comprises actuating means capable of ensuring the translational movement of said tool (21) and comprising a pneumatic or hydraulic cylinder acting on said mast (22).

7. Method for manufacturing from a sheet metal flank (T) a U-shaped section part (10) comprising a central sole (11), two lateral panels (12) extending on either side of this sole (11) and folded down opposite the latter, as well as a closing flap (13) attached to a longitudinal end of said sole (13) and folded down opposite the latter so as to close the corresponding longitudinal end of said part (10), said flap (13) being further attached laterally to two lateral flaps (14) folded down opposite the latter and covering an end portion of the outer face of said lateral panels (12), said method successively comprising: - a step of peripheral trimming of said sheet metal flank (T) to delimit around said sole (11) said lateral panels (12), said flap (13) and said flaps (14),- folding steps consisting of folding said side flaps (14) opposite said flap (13) and folding said side panels (12) opposite said sole (11), and - a folding step consisting of folding said flap (13) opposite said sole (11) so as to close said longitudinal end of said part (10); characterized in that said step of folding said flap (13) implements a device according to one of claims 1 to 6.,

8. Method according to claim 7, characterized in that it also comprises a perforating step consisting of producing by cutting openings in said sole (11) and / or said side panels (12).

9. Method according to one of claims 7 or 8, characterized in that it also comprises, after said folding steps, a step of producing electrical welding points between each said lateral flap (14) and the respective end portion of a said corresponding lateral panel (12).

10. Method according to one of claims 7 to 9, characterized in that it also comprises, before said folding steps, a step of stamping said sheet metal flank (T) in order to form ribs of stiffening (18) on said sole (11) and / or said side panels (12).

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