Abstract
A fold forming tool has a main body with a longitudinal axis and an active surface which is configured to fold over a flange, bent over from a metal sheet, onto the metal sheet by way of movement of the fold forming tool in the direction of the longitudinal axis along the flange in a working direction. The active surface extends in the direction of the longitudinal axis of the main body and is formed as a helical surface which is produced by way of a straight line being wound around a straight or curved helical axis, wherein the straight-line intersects the helical axis at an acute angle, as viewed in the working direction.
Claims
1. A method for producing a folded/bonded connection, the method comprising the steps of: providing an outer panel having a flange; arranging at least one edge region of an inner panel on the outer panel; arranging an adhesive on the edge region of the inner panel; and folding the flange over the edge region of the inner panel via a fold forming tool that is brought with its active surface into contact with the flange of the outer panel and is moved in a direction of its longitudinal axis along the flange, the fold forming tool having: a main body with a longitudinal axis; and an active surface positioned along an edge of the main body configured to fold over a flange, bent over from a metal sheet, onto the metal sheet by way of movement of the fold forming tool in a direction of the longitudinal axis along the flange in a working direction, wherein the active surface extends in the direction of the longitudinal axis of the main body and is in a form of a helical surface which is produced by a straight line helically wound around a rectilinear or a curved helical axis extending along the edge of the main body, wherein the straight line extends from the rectilinear or a curved helical axis at an acute angle, as viewed in the working direction.
2. The method according to claim 1, wherein an applied quantity of the adhesive is dimensioned in such a manner that a degree of filling of the folded/bonded connection of 200 or more is obtained, such that no adhesive emerges from the folded/bonded connection.
3. The method according to claim 1, wherein trimmed edges of the outer panel are rounded.
4. The method according to claim 3, wherein the outer panel and the inner panel are vehicle body components or add-on parts.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 is a schematic illustration of a method for producing a folded/bonded connection;
(2) FIGS. 2 to 5 show exemplary refinements of a fold forming tool;
(3) FIG. 6 is a sectional view of an exemplary folded/bonded connection;
(4) FIG. 7 is an exemplary fold forming device;
(5) FIG. 8 shows an exemplary panel arrangement during the formation of the folded/bonded connection;
(6) FIG. 9 is a sectional view of an exemplary folded/bonded connection in a vehicle;
(7) FIG. 10 shows a further exemplary folded/bonded connection in a vehicle; and
(8) FIG. 11 shows an exemplary vehicle with a folded/bonded connection.
DETAILED DESCRIPTION OF THE DRAWINGS
(9) In an exemplary method for producing a folded/bonded connection 1, first of all an outer panel 10 having a flange 12 is provided, to which an adhesive 20 is applied in the region of the folded connection to be formed. The trimmed edge of the outer panel is preferably rounded, but this is not illustrated here for illustrative reasons. An inner panel 30 is then arranged with respect to the outer panel 10 in such a manner that an edge region of the inner panel 30 comes to lie on the outer panel 10. The panels 10 and 30 are fixed with respect to each other by a fixing apparatus 40. A fold forming tool 50 is now guided with its contact surface 52 to the flange 12 and guided along the flange 12 in the direction of a longitudinal axis of the fold forming tool 50. The longitudinal axis corresponds in FIG. 1 to the z axis of the coordinate system shown.
(10) In FIG. 1, the fold forming tool 50 is moved out of the plane of the sheet. During the movement of the fold forming tool 50, the latter presses with its active surface 54 against the flange 12 and bends the latter over in the direction of the inner panel 30. The active surface 54 is configured as a helical surface according to the invention and as described above. In this case, the helical axis is a straight line and runs into the plane of the figure, and the active surface 54 is designed as a helical surface rotating to the right. The course of the active surface 54 means that the flange 12 is bent over continuously from the starting position into an end position 12A during the pass with the fold forming tool 50.
(11) FIG. 2 shows a variation of the fold forming tool 50, in which the latter also has a pressing element 58 which is arranged on the fold forming tool 50. During the use of the fold forming tool 50, the pressing element 58 presses the inner panel onto the outer panel and thus ensures that the panels are fixed with respect to each other. The pressing element 58 is designed in FIG. 2 by way of example as a pressure roller, the axis of rotation of which is arranged in the x direction, and therefore the pressure roller can roll on the panel during the folding. Alternatively, the pressing element can also be designed as a sliding runner.
(12) FIGS. 3 to 5 show three exemplary refinements of a fold forming tool. The same reference signs refer to the same features, and therefore the latter are not described again. The fold forming tools 50, 50A and 50B each have a main body 51 with a longitudinal axis L. The main body 51 also has a surface 52.
(13) At an angle to the surface 52, the fold forming tools 50, 50A and 50B each have active surfaces 54, 54A, 54B and 56, 56A, 56B with which the forming of the flange 12 takes place. Each of the fold forming tools 50, 50A and 50B has two active surfaces arranged one behind the other along the longitudinal axis L. Each active surface is designed as a helical surface described below, wherein the active surfaces 54, 54A and 54B are formed rotating to the right, and the active surfaces 56, 56A and 56B are formed rotating to the left. The helical surface is produced by screwing a straight line G1 or G2 about the helical axis S. In this case, the helical axis S is a curved axis and has the form of a circular arc segment. Alternatively, the helical axis S may also be a straight line which preferably runs parallel to the longitudinal axis of the main body 51. The straight lines G1 and G2 intersect the helical axis S andas viewed in the working direction A1 or A2 of the fold forming toolare inclined at an acute angle 1 or 2 in relation to the helical axis S. For example, the angle of inclination by which the straight line G1 or G2 intersects the helical axis S is in the range of 20 to 70 degrees and in particular in the range of 50 to 70 degrees and particularly preferably is 60. By this means, the resulting force vector K1 or K2 acts in the direction of the trimmed edge.
(14) The opposed active surfaces permit the use of the fold forming tool in both directions. The course of the active surfaces is in each case from the edge of the fold forming tool into the center. The active surfaces 54, 54A and 54B are therefore used when the fold forming tool is pushed to the right in the plane of the image. Conversely, the active surfaces 56, 56A and 56B are used if the fold forming tool is pushed to the left in the plane of the image. Alternatively, the fold forming tools can also be formed only with one active surface 54, 54A, 54B or 56, 56A, 56B.
(15) In the case of the fold forming tool 50 according to FIG. 3, the active surfaces 54 and 56 are designed as part of the main body 51 and are therefore a surface which is fixed with respect to the main body 51. During the folding operation, the flange 12 slides over the active surface 54 or 56. The pressing element 58 is not depicted in the illustration in FIG. 3.
(16) In the case of the fold forming tools 50A and 50B in FIGS. 4 and 5, needle rollers 540, 541, . . . and 560, 561, . . . are additionally arranged in the helical surface. The needle rollers are mounted rotatably in the control helical surface, as a result of which the friction of the active surfaces 54A, 54B, 56A and 56B with respect to the flange 12 is reduced. The needle rollers are arranged inclined with their axes of rotation in each case by an angle in relation to the longitudinal axis L of the main body 51. In each case 6 needle rollers are illustrated per active surface in FIGS. 4 and 5. This is purely by way of example; it is also possible for two or more needle rollers up to a multiplicity of needle rollers, e.g. more than 10 per active surface, to be provided.
(17) In the case of the fold forming tool 50A according to FIG. 4, the angles are standard for all of the needle rollers of an active surface. In the case of the fold forming tool 50B according to FIG. 5, the angles become smaller over the course of the active surfaces 54B or 56B. The needle rollers assist a targeted squeezing out of excess adhesive. The angle preferably lies in a range of 20 to 90 or in a range of 35 to 55. The fold forming tools 50A and 50B can likewise have a pressing element 58.
(18) FIG. 6 shows an exemplary folded/bonded connection 1 during the formation of same. The fold forming tool 50 is moved along the flange edge in working direction A, as a result of which the flange 12 is bent over in the direction of the inner panel. The angle of rotation of the active surface 54 is dimensioned in such a manner that the flange 12 is folded over completely by being passed over once by the forming tool 50. Owing to the configuration of the active surface 54 as an above-described helical surface, the adhesive (not illustrated here) emerges particularly uniformly and wets the end side of the flange 12, as a result of which good protection against corrosion is achieved.
(19) FIG. 7 shows an exemplary fold forming device 100 with a crimping bed 110 on which the outer panel 10 and the inner panel 30 are arranged and fixed by means of a fixing apparatus 115. Alternatively or additionally, in order to fix the panels, use can also be made of a fold forming tool with a pressing element 58, the pressing element 58 then acting as the fixing apparatus. Furthermore, the fold forming device 100 has a manipulator 120 in the form of an industrial robot, on the hand axis of which a fold forming tool 50 is arranged. Alternatively, the fold forming tools 50A or 50B can also be used. The fold forming device 100 furthermore has a control device 140 which is operatively connected to the manipulator 120 and to the fold forming tool 50. The control device 140 is designed, e.g. programmed, in order to move the fold forming tool relative to the fixing apparatus 115 or the panels 10 and 30 and, in the process, to bend over the flange 12 to produce the folded/bonded connection 1.
(20) FIG. 8 shows an exemplary folded/bonded connection at a time at which only part of the fold is bent over, in order to show the operative mechanisms acting in the method. The above-described fold forming tool (not illustrated here) is guided in the working direction A (illustrated by the arrow) along the fold edge and parallel to the latter. In this case, the flange 12 is continuously folded over in the direction of the inner panel 30 in accordance with the angle of rotation of the fold forming tool. In FIG. 8, the angle of rotation is by way of example 90, and the flange 12 which was previously angled at a right angle is deposited on the inner panel 30 after the pass with the fold forming tool. The angle of rotation therefore predetermines the change in angle which the flange 12 undergoes by means of the forming tool. Of course, the angle of rotation can also have different angles, preferably in a range of 30-90, or in a range of 45-90. The angle of rotation can also cover very much larger angular ranges, for example a range of 70-179.
(21) By means of the use of the fold forming tool according to the invention, which is guided parallel to and along the flange edge, the force vector K acting on the flange permanently acts in the direction of the trimmed edge 14 during the folding over of the flange. Adhesive which is arranged in the region of the folded connection is thereby pressed uniformly in the direction of the trimmed edge 14, as a result of which uniform wetting of the panels with adhesive is achieved. To improve the emergence of the adhesive, the trimmed edges 14 are preferably rounded. Furthermore, excess adhesive emerges substantially uniformly at the trimmed edge 14, thus resulting in a uniform crest line. Soiling of the panels is avoided and, in addition, the trimmed edge is protected by the adhesive which has emerged. In particular, the trimmed edge which faces the folded/bonded connection is wetted with adhesive. The trimmed edge which faces away therefrom, because of its rounding, is readily protected against corrosion by the cathodic dip-paint coating and paint. It follows from this that more extensive protection against corrosion in the form, e.g., of PVC sealing of the folded connection can be dispensed with.
(22) During the folding over of the flange 12, the latter follows the helical surface form of the active surface and the material undergoes stretching, in particular at the trimmed edge 14. The stretching is shown in FIG. 8 by the dashed line at the trimmed edge and the dotted line at the bending edge 16, the lengths of which differ by the extent of the stretching. The extent of the stretching of the material which occurs is influenced by the slope of the active surface which arises from the active surface length W, the angle of rotation and the width B of the flange 12. A slope selected to be too large would excessively stretch the material and would therefore cause corrugation of the folded connection or self-locking of the tool. For a compact design of the tool, the slope should not be selected to be too small either. In tests, for a flange width of 10 mm and an angle of rotation of 90 degrees, it has proven expedient, for example, if the active surface is formed over a length W of 60 mm. For a flange width of 15 mm and an angle of rotation of 90 degrees, an active surface length W of 90 mm has been shown to be expedient.
(23) FIG. 9 shows further exemplary folded/bonded connections 1A and 1B. Both folded/bonded connections have been formed with the above-described fold forming tool 50, 50A or 50B. The outer panel 10A is in each case bent with a flange 12A, 12B around an inner panel and adhesively bonded with an adhesive, not illustrated. The trimmed edges 14A and 14B of the outer panel, which are bonded into the folded/bonded connections 1A, are preferably rounded. The inner panel 30A is, for example, a door frame of the motor vehicle. Furthermore, seals 32, 34 are provided which seal the door in relation to the body 36 and a vehicle window 38.
(24) FIG. 10 shows a further folded/bonded connection 1C for illustrating the new corrosion protection concept which is possible by means of the invention. The corner of an outer panel 10C that forms a bodyshell part is illustrated. The outer panel 10C has a folded/bonded connection 1C at each of its longitudinal sides. The folded/bonded connections are preferably formed with the fold forming tool 50 according to the invention. The outer panel 10C is bent over with a flange portion by substantially 180 degrees. An adhesive 20 is arranged between the flange portion and opposite outer panel portion. The trimmed edges 14C and 14D of the outer panel 10C are rounded. By this means, the adhesive 20 has emerged with a rectilinear crest line from the fold and has wetted the adjacent trimmed edge 14C. The narrow gap of the folded connection and the inner trimmed edge 14C are therefore protected against corrosion by the adhesive 20. The trimmed edge 14D facing away from the folded/bonded connection is protected against corrosion by a cathodic dip-paint coating and paint. This novel concept makes it possible to dispense with more extensive protection against corrosion, and the folded/bonded connection 1C can remain in particular without PVC sealing, i.e. free from PVC sealing.
(25) FIG. 11 shows an exemplary motor vehicle 200 with an exemplary folded/bonded connection 1, 1A, 1B or 1C. Since the outer panel does not have to be covered because of the high surface quality of the folded/bonded connections 1, 1A, 1B or 1C, but rather can itself be used in the manner of a decorative cover, conventional covers to be mounted retrospectively can be dispensed with. In addition, the folded/bonded connections can be in particular free from PVC sealing. The profiles of the folded/bonded connections 1, 1A, 1B, 1C can be designed to follow the strake and in particular can be part of the vehicle outer skin. Particularly preferably, the folded/bonded connection forms a vehicle outer surface in the direct visible region SB of the vehicle. The vehicle outer surface can be, by way of example, a wheel arch, a door frame, a side frame, a sill or an add-on part.
List of Reference Signs
(26) 1, 1A, 1B, 1C folded/bonded connection 10, 10A, 10C outer panel 12, 12A, 12B flange 14, 14A trimmed edges 20 adhesive 30, 30A inner panel 32, 34 seal 36 body 38 vehicle window 40 fixing apparatus 50, 50A, 50B fold forming tool 51 main body 52 surface 54, 54A, 54B, 56, 56A, 56B active surface 540, 541, . . . 560, 561 needle rollers 58 pressing element 100 fold forming device 110 crimping bed 115 fixing apparatus 120 manipulator 140 control device 200 vehicle , 1 angle A, A1, A2 working direction B flange width G1, G2 straight line K, K1, K2 force vector L longitudinal axis S helical axis SB visible region W active surface length
