Head for folding the edge of a metal sheet by at least 160° with bearing roller and associated folding method

Abstract

The invention relates to a head (8) for folding an edge (2.1) of a metal sheet (2), comprising a support (10); an edge contact surface (2.1), which surface is attached to the support (10) and is capable of folding the edge (2.1) as it moves along the edge; a roller (14) bearing on a die (6), which roller is attached to the support (10); the contact surface extending along a twisted profile on a folding blade (12) and being configured to fold the edge (2.1) by at least 160° in a folding direction against another edge (4.1) of another metal sheet (4); and the bearing roller (14) being capable of being rotated about an axis that is stationary relative to the support (10).

Description

technical field

[0001] The invention relates to the field of shaping stamped parts, in particular automotive bodywork elements, more particularly by folding. Previous technique

[0002] The published patent document WO 2017 / 144791 A1 discloses a method for bending one edge of a metal sheet against another edge of a different metal sheet, for the purpose of crimping the edge and the other edge, by moving a bending head, by a robotic arm, along the edge in question. The bending head comprises a blade with a twisted contact surface configured to bend the edge against the other edge.

[0003] The cross-sectional profile of the contact surface exhibits a variation in inclination along said surface of approximately 180°, allowing the edge to be bent 180° around the edge of the other. A single pass of the blade along the edge thus allows it to be bent against the other edge.

[0004] In the crimping described above, the tilting movement of the edge around the edge of the other edge may lack precision regarding the height of the 180° fold, mainly due to differences in stiffness in different directions of the robotic arm moving the folding head.

[0005] The published patent document EP 1 685 915 A1 discloses a bending head capable of crimping two edges of sheet metal by folding one edge over the other at approximately 90°. The bending head comprises two rollers with different angles of inclination, so that the first roller performs a first fold and the second roller a second fold. The edge is thus folded against the other edge in a single pass of the bending head. The first roller is mounted to slide on a support of the head, against an elastic force or controlled by a hydraulic cylinder, so as to be able to follow a non-straight contour of the edge to be folded. A support roller is fixed to the first roller on the sliding support to ensure proper tracking of the non-straight contour.This solution is interesting but does not allow for better control of the fold position because the first and second rollers are limited to folding down the previously folded edge to approximately 90°.

[0006] The published patent document DE 10 2014 015020 A1 discloses a folding head according to the preamble of claim 1. Description of the invention

[0007] The invention aims to overcome at least one drawback of the aforementioned prior art. More specifically, the invention aims to enable the crimping of two edges of metal sheets where one edge is folded approximately 180° over the other edge, with better control of the height of the resulting 180° fold.

[0008] The invention relates to a bending head for the edge of a sheet metal part, comprising a support; a contact surface with the edge, fixed to the support and capable of bending said edge during movement along said edge; a support roller on a die, fixed to the support; notable in that the contact surface extends along a twisted profile on a bending blade and is configured to bend the edge at least 160° in a bending direction against another edge of a different sheet metal part; and the support roller is rotatable about an axis fixed relative to the support. According to the invention, the support roller is adjustable in position relative to the support in the bending direction by means of one or more shims of varying thicknesses.

[0009] According to an advantageous embodiment of the invention, the folding head comprises a coupling piece to a robotic arm, the support being movable in translation relative to the coupling piece against an elastic force.

[0010] According to an advantageous embodiment of the invention, the support is movable in translation relative to the coupling piece in the folding direction.

[0011] According to an advantageous embodiment of the invention, the coupling piece comprises a fixing flange extending in a transverse plane, preferably perpendicular, to the folding direction.

[0012] According to an advantageous embodiment of the invention, the coupling piece comprises a projecting part which engages movably in translation with an elongated portion of the support.

[0013] According to an advantageous embodiment of the invention, the protruding portion forms a cylinder and the elongated portion forms a pin that slides into said cylinder.

[0014] According to an advantageous embodiment of the invention, the support roller is oriented to bear against the die in the folding direction.

[0015] According to an advantageous embodiment of the invention, the support roller is rotatable around an axis fixed relative to the support and oriented along a direction perpendicular to the folding direction or inclined at 15° or less with respect to said perpendicular direction.

[0016] The invention also relates to a method for bending the edge of a sheet metal part comprising the following steps: (a) placing the sheet metal on a die; (b) placing another sheet metal part on top of the first, with another edge adjacent to the first; (c) bending the edge against the other edge by moving a bending head along said edge; notable in that the bending head is according to the invention, and the movement of the bending head in step (c) includes continuous rolling of the support roller on the die along the edge. Advantageously, in step (c), the edge is bent at least 160°. Advantageously, the sheet metal part is an outer wall of a motor vehicle sunroof, and the edge is pre-bent at 90°, within a tolerance of ±20°, and defines the sunroof opening.Advantageously, the other metal sheet is a sunroof lining for a motor vehicle, and the other edge is pre-bent at 90°, within a tolerance of ±20°, and delimits the opening of the roof.

[0017] The measures of the invention are advantageous in that they allow for the efficient and controlled crimping of two metal sheet edges by folding and folding one edge over the other, with precise control over the height of the folded edge. The use of a bending blade with a warped and twisted contact surface is beneficial because it allows for a bend and fold of approximately 180° in a single pass, unlike bending rollers which, due to their cylindrical annular contact surfaces, only allow each edge to be bent at a limited angle, typically up to 45°. Providing a fixed support roller relative to the bending blade thus allows for control of the contact surface position on the bending blade relative to the rest of the metal sheets and, consequently, control of the geometry of the folded edge. Brief description of the drawings

[0018] [ Fig 1 ] is a cross-sectional view of two crimped metal sheet edges, according to the invention; [ Fig 2 ] is a perspective view of an exterior wall and sunroof lining of a motor vehicle, the edges of which are being crimped by moving a folding head; Fig 3 ] is a cross-sectional view of the folding head of the figure 2 . Detailed description

[0019] There figure 1 in cross-section view of two edges of metal sheets crimped by folding one of said edges against the other of said edges.

[0020] The metal sheet 2 includes an edge 2.1 that has been previously bent at approximately 90°, for example by "falling" during a forming operation on a stamping press. The other metal sheet 4 also includes an edge 4.1 that has been previously bent at approximately 90°, similarly to edge 2.1, and is positioned against said edge 2.1. The latter is bent at 180° around the edge 4.2 of the other edge 4.1 and folded over against it, thus forming a 180° bend 2.2 and a folded portion 2.3. The edge 2.1 before bending and folding is shown as a dashed line, corresponding to the 180° bend and the folded portion 2.3. The folding and folding of edge 2.1 can be done by resting on the edge 4.2 of the other edge 4.1 but this has the consequence that the height H of the folded edge 2.1 is determined by the height of the other edge 4.1. However the latter may have a variable height along its extent, leading to a non-constant height H along the edges 2.1 and 4.1 thus crimped.

[0021] It is desirable to obtain a height H of the folded edge 2.1 that is constant and controlled along its entire length. To this end, the invention provides that the edge 2.1 in question is folded around and folded against the other edge 4.1 with a gap in the bottom of the groove formed by the 180° fold 2.2, as illustrated in the figure 1 This approach makes it possible to overcome the tolerances of the height of the other edge 4.1. To this end, edge 2.1 is folded around and folded against the other edge 4.1 using a folding head and a corresponding method illustrated in figures 2 And 3 .

[0022] There figure 2 is a perspective view of an outer wall 2 and a lining 4 of a motor vehicle sunroof, the edges of which are crimped by the movement of a folding head. The outer wall corresponds to the metal sheet 2 of the figure 1 and the lining corresponding to the other metal sheet 4 of the figure 1 The respective edges 2.1 and 4.1 visible at the figure 1 are present at the figure 2 along the opening of the sunroof, although difficult to see. The metal sheet 2 is placed against a die 6 specially sized and shaped for this operation.

[0023] A folding head 8 is applied against the edge to be folded and moved along said edge in order to fold it and fold it against the other edge, so as to obtain the crimping illustrated in the figure 1 The folding head 8 is supported by a robotic arm not shown, but which is well known to those skilled in the art.

[0024] There figure 3 is a cross-sectional view of the folding head 8.

[0025] The bending head 8 comprises a support 10 to which a bending blade 12 and a support roller 14 are attached. The bending blade 12 may be as disclosed in published patent document WO 2017 / 144791 A1, that is, essentially formed of a solid body having a contact surface with the edge, said surface being warped and twisted essentially in a direction generally parallel to the working direction of the blade. The surface in question may correspond to a surface formed by a preferably straight generatrix that moves in translation along the edge of the bending blade 12 while undergoing a rotation corresponding to the bending and folding of the edge. The variation in inclination of the cross-sectional profile of the contact surface, from an entry zone to an exit zone, essentially corresponds to the folding angle that must be applied to the edge.

[0026] The bending head 8 also includes a coupling piece 16 for the robotic arm. The coupling piece 16 includes a flange 16.1 for fixing to the robotic arm and a cylindrical portion 16.2 projecting from the fixing flange 16.1. The support 10 is mounted to move in translation against an elastic force on the coupling piece 16. In this case, the support 10 comprises a central part 10.1 on which the blade 12 and the support roller 14 are fixed, and an elongated part 10.2, forming a spindle, which slides into the cylindrical part 16.2 of the coupling piece 16. It can be observed that the spindle comprises a proximal portion with a cylindrical outer surface that slides in a guide ring 16.3 mounted on the distal end of the cylindrical part 16.2 of the coupling piece 16, and a distal, end portion supporting a slide 10.3 that slides in a bore of said cylindrical part 16.2 of the coupling piece 16. A compression spring 18 is housed in the cylindrical portion 16.2 of the coupling piece 16, with one end against a bearing surface 16.4 of said cylindrical portion 16.2 and the other end against a support ring 10.4 fixed to the spindle formed by the elongated portion 10.2 of the support 10. In this embodiment, the spindle forms a shoulder against which the support ring 10.4 abuts. The spring 18 thus exerts an elastic force on the support 10, via the support ring 10.4 and the elongated portion 10.2 of said support 10.

[0027] With reference to the detailed view of the figure 3It can be observed that the folding blade 12 has its contact surface against the folded portion 2.3 of the edge 2.1 of the metal sheet 2, corresponding in this case to an outer roof skin, and against the other edge 4.1 of the other metal sheet 4, corresponding in this case to a roof lining. The folding direction is therefore vertical and parallel to the other edge 4.1. The support roller 14 is adjacent to the folding blade 12 and is configured to bear against the die 6 in a direction corresponding to the folding direction. More precisely, the axis of rotation of the support roller 14, represented by the generally horizontal center line, is perpendicular to the folding direction, which is in this case vertical, or at least forms an angle of 15° or less with said perpendicular.

[0028] During the movement of the bending head 8 along the edge 2.1 to be bent and folded against the other edge 4.1, the support roller is applied against a reference surface of the die 6, adjacent to said edges 2.1 and 4.1, so as to control and regulate the height of the bending blade 12 and therefore its contact surface with the edge 2.1. This contact is facilitated by the sliding mounting against an elastic force of the support 10 on the coupling piece 16. The robotic arm to which the coupling piece 16 is attached can thus, during the movement of the bending head 8 along the edge 2.1, exert a force on the support 10 via the spring 18, this force then being absorbed by the support roller 14 rolling on the die 6. This elastic force then ensures permanent contact of the support roller 14 on the die during the movement of the bending head 8 along the edge 2.1.1 to fold and fold, and, therefore, an exact positioning, in the folding direction, of the contact surface of the folding blade 12. These measures thus make it possible to make a groove bottom clearance in the fold 2.2 at 180° to the edge 2.1, and thus to make a constant height H of the edge 2.1, as discussed above in relation to the . figure 1 .

[0029] It should be noted that the sliding against an elastic force in the bending head 8, as described above, is optional, as the movement by the robotic arm can be sufficiently precise to ensure continuous contact of the support roller 14 against the die. The robotic arm also possesses intrinsic elasticity that can replace or supplement the sliding assembly against an elastic force described above.

[0030] Again, referring to the detailed view of the figure 3It can be observed that the bending blade 12 is mounted on an intermediate piece 20 with an L-shaped profile, allowing the support roller 14 to be housed in the hollow of the L, directly adjacent to the bending blade 12, which is itself fixed to one end of the shorter arm of the L. The support roller 14 is mounted on the intermediate piece 20 via a shim of thickness 22, ensuring precise and rigid positioning. This shim of thickness 22 can thus be supplemented or replaced by one or more other shims of thickness.

[0031] Still referring to the detailed view of the figure 3It can be observed that the die 6 comprises two distinct parts, namely an inner part 6.1 and an outer part 6.2 adjacent to the inner part 6.1, although it may also be a single piece. The rolling surface 6.2.1 of the die 6, on which the support roller 14 rolls, is directly adjacent to the lateral bearing surface 6.2.2 of the edge 2.1 and is vertically aligned with the frontal bearing surface 6.1.1 of the metal sheet 2. The rolling surface 6.2.1 is advantageously perpendicular to the lateral bearing surface 6.2.2 or inclined at 15° or less with respect to said perpendicular. It is understood, however, that the rolling surface 6.2.1 may be at different heights relative to the frontal bearing surface 6.1.1.

[0032] In the description of the invention given above, the bending and folding angle of the edge of the sheet metal is approximately 180°. However, it is understood that this angle can be smaller, for example, down to 160°. In this case, the edge of the sheet metal in its unfolded state can be pre-bent at a small angle, for example, up to 20°. Similarly, the bending and folding angle can be larger, in which case the edge in its unfolded state can be pre-bent in the opposite direction to the folding. In both cases, the advantages of the invention are present, given the small value of the pre-bending angle.

Claims

1. Bending head (8) of an edge (2.1) of a metal sheet (2), comprising: - a support (10); - a surface for contact with the edge (2.1), fixed to the support (10) and capable of folding said edge (2.1) during a movement along said edge; - a roller (14) for bearing on a die (6), fixed to the support (10); the contact surface extends in a twisted profile on a folding blade (12) and is configured to fold down the rim (2.1) by at least 160° in a folding management against another rim (4.1) of another metal sheet (4); and the bearing roller (14) is rotatable about an axis fixed by report to the support (10), Characterised in that the support roller (14) is adjustable in position by report with the support (10) in the folding management, by means of one or more shims (22).

2. Folding head (8) according to claim 1, comprising a component (16) for coupling to a robotic arm, the support (10) being movable in translation by report with the coupling component (16) against an elastic force.

3. Folding head (8) according to claim 2, in which the support (10) is movable in translation by report with the coupling component (16) in the folding management.

4. Folding head (8) according to one of Claims 2 and 3, in which the coupling component (16) comprises a fixing flange (16.1) extending in a drawing perpendicular to the folding management.

5. Folding head (8) according to one of Claims 2 to 4, in which the coupling component (16) comprises a protruding part (16.2) engaging in translational motion with an elongate portion (10.2) of the support (10).

6. Folding head (8) according to claim 5, in which the projecting portion (16.2) forms a cylinder and the elongated portion (10.2) forms a pin slidably engaging in said cylinder.

7. Folding head (8) according to one of Claims 1 to 6, in which the bearing roller (14) is orientated so as to bear on the die in the folding management.

8. Folding head (8) according to one of Claims 1 to 7, in which the bearing roller (14) is rotatable about an axis which is stationary by report with the support (10) and orientated in a management perpendicular to the folding management or inclined by 15° or less by report with the said perpendicular management.

9. Process for folding an edge (2.1) of metal sheet (2) comprising the following steps: (a) depositing the metal sheet (2) on a die (6); (b) placing another metal sheet (4) on the metal sheet (2), with another edge (4.1) adjacent to the edge (2.1); (c) folding the edge (2.1) against the other edge (4.1) by moving a folding head (8) along said edge (2.1); characterised in that the folding head (8) is according to one of claims 1 to 8, and the movement of the folding head (8) in step (c) comprises a continuous rolling of the bearing roller (14) on the die (6) along the edge (2.1).

Images