METHOD FOR CALIBRATING A METAL PROFILE BLANK WITH AT LEAST ONE SOLID WALL

Description

[0001] The invention relates to a method for calibrating a metallic profile blank with at least one solid wall according to the preamble of patent claim 1.

[0002] In automotive and motor vehicle construction, profiles, especially hollow-chamber profiles made of aluminum or steel alloys, are used for many applications today as materials for floors and walls that must be joined together. This can, for example, provide an interior space for batteries or similar components. The interior space is sealed fluid-tight by a cover and a seal. The floor and walls, each made of one or more profiles, are also joined fluid-tight, for example, by friction stir welding or cold press joining.

[0003] Due to the large dimensions of the containers, sometimes several square meters in size, the challenge when manufacturing profiles for such applications is that manufacturing tolerances of the profiles, particularly wall thicknesses, external dimensions, and the like, from an extrusion process or, in the case of steel materials, also from the roll forming process, are relatively large, making it difficult to couple the individual parts together or to join them. As a result, the large tolerances are reduced or compensated for by time-consuming and cost-intensive machining of the joining areas, particularly in the case of frame profiles designed as hollow chamber profiles. The required oversize of the profiles also entails a higher overall weight, since the wall thickness must be greater than necessary for structural strength. This is questionable both economically and ecologically.Alternatively, it is also known that the profiles are aligned with each other in a clamping fixture, especially before joining, and the joining layer is positioned and then joined. However, this approach introduces high residual stresses, which can adversely affect the durability and crash properties of the parts produced in this way, for example, a battery container.

[0004] In many cases, tolerance compensation elements must also be arranged on such profiles that are to be joined together in order to connect the profiles, which are joined with little dimension accuracy, for example with internal transverse walls or internal longitudinal walls.

[0005] EP 1 285 705 A2, for example, discloses a hollow chamber profile in which a hollow chamber is expanded by pulling a mandrel through it, thereby defining the surfaces of the hollow chamber profile and thus easily calibrating it. In principle, hollow chamber profiles can be calibrated very well using such expansion processes. However, the equipment and process engineering required is relatively large and complex, as the mandrels used to expand the hollow chamber profile must be adapted very precisely to the respective hollow chamber of the hollow chamber profile. It should be borne in mind that the mandrel must both engage the hollow chamber of the hollow chamber profile at the start of the expansion process and ensure that the exact and calibrated shape of the hollow chamber profile is achieved at the end of the calibration.

[0006] A similar process is described in DE 10 2014 004 183 A1. It involves calibrating a hollow chamber profile using internal high-pressure forming.

[0007] CN 109 175 014 A also discloses a method for deforming purlins used in solar and photovoltaic systems in mountings for solar and photovoltaic modules. The purlins in this case are profiles that, for improved stacking after dismantling a solar and photovoltaic system for reuse, are subjected to a deformation process that has all the features of the preamble of patent claim 1.

[0008] DE 10 2005 020 727 A1 describes a multi-chamber tube designed as a heat exchanger in which the inner webs are compressed and deformed.

[0009] It is therefore an object of the invention to provide a method for calibrating a metallic profile blank having at least one solid wall according to the preamble of patent claim 1, in which no costly and process-complex tools have to be produced for calibration, wherein both plate-shaped profile blanks and hollow chamber profile blanks can be calibrated.

[0010] With regard to the method, this object is achieved by a method for calibrating a metallic profile blank with at least one solid wall with all the method steps of patent claim 1. Advantageous embodiments of the method can be found in subclaims 2 to 9.

[0011] The method according to the invention for calibrating an extruded metallic profile blank with at least one solid wall is characterized by the following process steps: a) Providing a metallic profile blank with at least one - in particular plate-shaped - element with a longitudinal extension, a transverse extension and a vertical extension b) Inserting at least one end region of the element of the profile blank into a cavity of an open pressing tool, c) Closing the pressing tool in such a way that surfaces of the pressing tool are moved in a main closing direction perpendicular to the longitudinal extension of the profile blank until they come to rest on a pair of surfaces of the at least one end region of the element of the profile blank to be calibrated, which are opposite one another at a distance, d) Further closing of the pressing tool in the main direction,e) closing the pressing tool in a secondary direction perpendicular to the main direction and to the longitudinal extent of the profile blank until surfaces of the pressing tool itself come to rest on surfaces of at least one end region of the element of the profile blank to be calibrated, f) further closing the pressing tool in the secondary direction, whereby a plastic deformation of the profile blank produced by compression takes place in the main or secondary direction with reduction or elimination of the bending produced in step d), g) opening the pressing tool, h) removal of the profile blank now calibrated to the final profile.

[0012] According to the invention, it is provided that in step d) a deformation in at least one end region of the element of the profile blank and a bending of the plate-shaped element of the profile blank in the secondary direction perpendicular to the main direction and to the longitudinal extent of the profile blank takes place by compression and in step f) a plastic deformation of the profile blank in the main or secondary direction produced by compression takes place with reduction or cancellation of the bending produced in step d).

[0013] It should be noted that the chronological sequence of the individual process steps a) to h) represents a particularly advantageous embodiment of the invention. However, the invention is not limited to this. Rather, it is also possible, for example, to perform process steps c) and e) simultaneously.

[0014] The method according to the invention makes it possible to calibrate a wide variety of extruded metallic profile blanks, particularly in their end regions, in order to compensate for connection tolerances and to enable the finally calibrated profiles to be joined to other components.

[0015] The profile blank comprises at least one element – ​​in particular, but not necessarily, a plate-shaped element – ​​with a longitudinal extension, a transverse extension, and a vertical extension. By plastically deforming the element in both the main and secondary directions, the element is calibrated accordingly. This may also lead to an expansion of the plate-shaped element in the longitudinal direction, which can, however, already be taken into account during production of the profile blank. It is essential that the element is compressed and plastically deformed in the main and secondary directions, while simultaneously undergoing bending in the secondary direction. This bending is removed by final compression or plastic deformation. After the profile blank has been calibrated to the final profile according to the aforementioned embodiments, the pressing tool is opened and the profile is removed from the pressing tool.

[0016] A fundamental advantage of the invention is that the profile blanks can be manufactured with minimal weight, since no machining steps are necessary for calibration.

[0017] According to a first advantageous embodiment of the invention, a profile blank made of an extruded aluminum alloy is used. Such materials have proven advantageous in vehicle construction due to their light weight and the associated energy savings during operation of the motor vehicle.

[0018] To prevent or minimize abrasion on the profile blank and the press tool during the plastic deformation or calibration of the profile blank within the press tool, a particularly advantageous embodiment of the invention provides for a lubricant to be applied between the contact surfaces of the press tool and the profile blank that come into contact during compression or plastic deformation. This prevents or significantly minimizes abrasion caused by friction. The lubricant can be either a separate lubricant applied to the profile blank before calibration or a coating applied to contact surfaces of the profile tool.

[0019] According to another advantageous embodiment of the invention, during the plastic deformation of the at least one plate-shaped element, overcalibration is performed to compensate for any elastic springback of the element. This takes into account the inherent material property of springback during plastic deformation of the respective profile blanks through elastic recovery, allowing for very precise calibration. This makes it possible to calibrate profile blanks accordingly, so that only very small compensation tolerances occur during subsequent joining with other components.

[0020] According to a further concept of the invention, it is provided that a flat or plate-shaped profile blank is used as the profile blank, in particular with at least two different surface sections of opposing surfaces that define different wall thicknesses. Such a profile blank can be plastically deformed in a simple manner in the main and secondary directions or in the transverse and vertical directions using the method according to the invention, wherein the aforementioned springback can occur. Taking the springback into account, such a profile blank can be calibrated very precisely, thus enabling simple subsequent and precisely fitting joining with other components. Profiles produced in this way can be used, for example, as flange plates for bumper systems of a motor vehicle.

[0021] According to another concept of the invention, it is provided that a hollow chamber profile with at least one hollow chamber is used as the profile blank. The at least one hollow chamber of such a profile blank contains several - in particular, but not necessarily plate-shaped - elements that are plastically deformed according to the method described above, thereby enabling calibration of the entire at least one hollow chamber of the profile blank and thus of the profile blank itself. This allows hollow chambers of profile blanks or such profile blanks to be calibrated very precisely in a simple manner, without the need for expensive and complex tools to expand the hollow chamber or the need for machining processes for calibration.Advantageously, a floating mandrel is used as a tool inside the at least one hollow chamber, against which the walls of the individual plate-shaped elements of the hollow chamber rest during calibration or compression. This floating mandrel is machined with great precision, as it essentially reproduces or predetermines the calibrated shape of the hollow chamber within.

[0022] When using profile blanks with at least one hollow chamber, it has proven advantageous for the at least one - in particular solid or hollow - internal tool, in particular in the form of a floating mandrel, to be inserted, prior to compression, preferably at least 50 mm into the end region of the at least one hollow chamber of the profile blank. This ensures that the end regions of the hollow chamber intended for subsequent joining with other components are calibrated accordingly. Calibration of other regions of the hollow chamber is not necessary for joining and can therefore be omitted. This provides a particularly advantageous process both economically and ecologically, since calibration only takes place in the necessary regions of the hollow chamber and no complex tools are required.

[0023] It is particularly advantageous to use a profile blank with at least one hollow chamber that has a polygonal, particularly square, profile cross-section. Such profiles are widely used in automotive construction, and their further processing is integrated into many processes during the manufacture of a motor vehicle.

[0024] Furthermore, it has proven more sensible for both the height and the width of the end region of the hollow chamber profile blank to decrease by at least 0.2%, in particular between 0.3% and 5%, during calibration or during plastic deformation. It is particularly advantageous that the profile blank can be easily manufactured with appropriate tolerances and adjusted to the necessary dimensions for subsequent joining with other components during the calibration process. Springback can also be easily taken into account as a material property during the production of the profile blank, thus enabling very precise production and calibration of the profile blank. It is particularly advantageous if the wall thickness of the hollow chamber is maintained during calibration.As a result, the wall thicknesses of the hollow chamber are identical for both the profile blank and the calibrated profile.

[0025] Further objects, advantages, features and possible applications of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0026] They show: Figure 1: an embodiment of a first profile blank for producing a profile calibrated according to the invention, Figure 2: a first embodiment of a pressing tool for calibrating the profile blank according to Figure 1 , Figures 3 to 5: Representation of individual process steps of a process according to the invention for calibrating the profile blank according to Figure 1 in the pressing tool according to Figure 2, Figure 6: a second embodiment of a profile blank for producing a Figure 7: calibrated profile according to the invention, an embodiment of a pressing tool for calibrating the profile blank according to Figure 6 , Figures 8 to 10: individual process steps of a process according to the invention for calibrating a profile blank according to Figure 6 with a pressing tool according to Figure 7 , Figure 11: a third embodiment of a profile blank for producing a profile calibrated according to the invention, Figure 12: an embodiment of a tool for calibrating a profile blank to a profile according to Figure 11 , Figures 12 to 17: Representation of individual process steps for calibrating a profile blank to a profile according to Figure 10 with a pressing tool according to Figure 11, each with a detailed representation.

[0027] In the Figure 1a plate-shaped element 3 is shown, which consists as a profile blank 101 made of an aluminum alloy and was produced in an extrusion process and essentially consists of a solid wall 2. The plate-shaped element 3 of the profile blank 1 has a longitudinal extent, a vertical extent and a transverse extent. The profile blank 1 is cuboid-shaped and has surfaces 8, 9 and 12, 13 which extend along the longitudinal extent of the cuboid, plate-shaped element 3 of the profile blank 1 in its longitudinal extent. The profile blank 101 can also have at least two surface sections of different wall thickness in cross-section; this can be implemented particularly easily by extrusion, even with relatively large thickness jumps and even in the tightest of spaces or with a small cross-sectional width.

[0028] In the Figure 2A pressing tool 5 is now shown, which has a cavity 4 for inserting the profile blank 1 and has a lower punch 14, an upper punch 15, a left punch 16, and a right punch 17. The punches 14 to 17 have surfaces 6, 7 and 10, 11, which, in the calibration process described below, come into contact with the surfaces 9, 8 and 12, 13 of the profile blank 1 designed as a plate-shaped element 3 or solid wall 2.

[0029] In the Figure 3 a process step of the method according to the invention is shown, after which the profile blank 1 according to Figure 1 into the cavity 4 of the pressing tool 5 according to Figure 2was inserted. In this case, surface 7 of the upper punch 15 and surface 6 of the lower punch 14 of the pressing tool 5 come to rest on surfaces 9 and 8, respectively, of the profile blank 1. Surface 10 of the left punch 16 and surface 11 of the right punch 17 are not yet in contact with surfaces 12 and 13, respectively, of the profile blank 1, which is designed as a plate-shaped element 3. Rather, there is still a gap between these surfaces.

[0030] In the now Figure 4 In the process step shown, the upper punch 15 and the lower punch 14 of the pressing tool 5 have now already moved against each other, whereby the profile blank 1 designed as a plate-shaped element 3 or solid wall 2 has already been deformed in its vertical direction and has also undergone bending into the free spaces between the walls 10 and 11 of the left and right punches 16, 17 and the walls 12, 13 of the profile blank.

[0031] In a further process step, the left punch 16 and the right punch 17 of the pressing tool 5 are now moved against each other in such a way that the profile blank 1 is now plastically deformed in its transverse extent, eliminating the previously generated bending.

[0032] The profile blank 1 now arranged in the pressing tool 5 is shown in the illustration according to Figure 5 Overcalibrated. This overcalibration is compensated for after the pressing tool 5 is opened and the overcalibrated profile blank 1 is removed by the material's inherent springback, which occurs during compression and plastic deformation, so that the profile blank 1 is then finally calibrated to the desired profile. The now finally calibrated profile can now be forwarded to further processing.

[0033] In the Figure 6A second embodiment of a profile blank 101 for producing a profile is now shown. The profile blank 101 is designed as a two-chamber hollow profile with hollow chambers 120 and 121 arranged one above the other, which are separated from each other by a partition wall 122. The two-chamber hollow profile of the profile blank 101 has a lower surface 108 and an upper surface 109, as well as a left surface 112 and a right surface 113. These surfaces 108, 109, 112, and 113 each belong to a flat element 103 designed as a solid wall 102.

[0034] In the Figure 7 A pressing tool 105 is now shown, with which a profile blank 1 designed as a two-chamber hollow profile according to Figure 6can be calibrated. All elements are shown here with the exception of the floating mandrels provided for the hollow chambers 120 and 121. These are a lower punch 114, an upper punch 115 as well as a left punch 116 and right punch 117. The upper punch 115 and the lower punch 114 can be moved relative to each other, for example, via a hydraulic system not shown here. The left punch 116 and the right punch 117 are slightly wedge-shaped in the present case, so that a drive element 123 with likewise wedge-shaped legs 124 and 125 can be moved relative to each other under support on support elements 126 and 127. The profile blank 101 is inserted into the cavity 104 arranged between the punches 114 to 117 according to Figure 6for calibration. The punches 114 to 117 again have surfaces 106, 107, 110, and 111, which come into contact with the surfaces 108, 109, and 112 and 113 of the profile blank 101 during calibration.

[0035] In the Figure 8The profile blank 101 is now shown inserted into the cavity 104 of the pressing tool 105. In this illustration, the pressing tool 105 is still in its open position, with the previously mentioned floating mandrels 118 and 119 already inserted into the hollow chambers 120 and 121. These floating mandrels 118 and 119 are designed as solid internal tools and have an outer contour that corresponds to the inner contour of the hollow chambers 120 and 121 to be calibrated of the profile finally produced from the calibrated profile blank 101. The surface 108 of the profile blank 101 is already in contact with the surface 110 of the lower punch 114. Between the other surfaces 112, 113 and 109 of the profile blank 101 there is still a gap to the surfaces 110, 111 and 107 of the punches 115, 116 and 117.

[0036] As now in Figure 9As shown, the upper punch 115 is moved against the lower punch 114 of the pressing tool 105. Surface 107 of the upper punch 115 now comes to rest against surface 109 of the profile blank 101, and as the punches 115 and 114 continue to move against each other, the walls of the profile blank 101 having surfaces 112 and 113 are compressed, whereby these walls are both deformed and bent. The compression occurs in such a way that the floating mandrels 118 and 119 now abut against the walls of the profile blank 101 having surfaces 106 and 107, and come to rest there, while the profile blank 101 continues to undergo plastic deformation.

[0037] In the Figure 10The final step of the pressing or compression process with an overcalibration of the profile blank 101 is now shown. Here, the left punch 116 and the right punch 117 are now moved against each other by the drive element 123 and its legs 124 and 125 with the counter elements 126 and 127 in such a way that the gap between the walls 110 and 111 of the punches 116 and 117 and the walls 112 and 113 of the profile blank 109 disappears again, and the profile blank is further plastically deformed, eliminating the previously created bending and thus overcalibrated. This overcalibration is eliminated after the profile blank 101 is removed from the cavity 104 after the pressing tool 105 is opened, due to the springback property inherent in the material, so that the finally calibrated profile is created.It should also be noted that the calibration of profile blank 101 does not change its wall thickness. The thickness of the walls of the profile blank corresponds to the wall thickness of the calibrated profile. The now calibrated profile can then be used for further applications.

[0038] Figure 11 now shows a third embodiment of a profile blank to be calibrated using the method according to the invention. In the profile blank 201 of the Figure 11This is a multi-chamber profile with a very complex design, comprising six different hollow chambers 220, 221, 228, 229, 230, and 231. The individual hollow chambers are separated from one another by partition walls 221, 232, 233, 234, and 235. The multi-chamber hollow profile of the profile blank 201 has a lower surface 208, an upper surface 209, a left surface 212, and a right surface 213. These surfaces 208, 209, 212, and 213 each belong to a flat element 203 formed as a solid wall 202.

[0039] Calibration using conventional hydroforming methods would be difficult due to the complex tool design. However, the calibration method according to the invention allows for simple calibration.

[0040] The pressing tool 205, with which the profile blank 201 of the Figure 11 is calibrated is essentially in the Figure 12shown, wherein the profile blank 201 is already inserted into the cavity 204 of the pressing tool 205.

[0041] The structure of the pressing tool 205 essentially corresponds to that of the pressing tool 105 of the Figures 7 to 10 , whereby only the upper punch 215 and the left and right punches 216 and 217 are adapted to the geometry of the profile blank 201 and the punch 215, respectively. For the six cavities 220, 221, 228, 229, 230, 231 of the profile blank 201 used here, six different floating mandrels 218, 219, 236, 237, 238 and 239 are used, which are inserted into these cavities 220, 221, 228, 229, 230, 231 during calibration. A detailed representation of the profile blank 201 inserted into the pressing tool 205 is shown in Figure 13 shown.

[0042] As now in Figure 14 and Figure 15As shown, the upper punch 215 is moved against the lower punch 214 of the pressing tool 205. The surfaces 207 of the upper punch 215 now come to rest against the surfaces 209 of the profile blank 201, and as the punches 215 and 214 continue to move against each other, the walls of the profile blank 201 having the surfaces 212 and 213 are compressed, whereby these walls are both plastically deformed and bent. The compression occurs in such a way that the floating mandrels 218, 219, 236, 237, 238, and 239 now abut against the walls of the profile blank 201 having the surfaces 208 and 209 and come to rest there, while the profile blank 201 continues to be plastically deformed.

[0043] In the Figures 16 and 17The final step of the pressing or compression process with an overcalibration of the profile blank 201 is now shown. Here, the left punch 216 and the right punch 217 are now moved against each other by the drive element 223 and its legs 224 and 225 as well as the counter-elements 226 and 227 in such a way that the gap between the walls 210 and 211 of the punches 116 and 117 and the walls 212 and 213 of the profile blank 209 disappears again, and the profile blank 201 is further plastically deformed, eliminating the previously created bending and is thereby overcalibrated. This overcalibration is eliminated after the profile blank 201 is removed from the cavity 204 after the pressing tool 205 is opened, due to the springback property inherent in the material, so that the finally calibrated profile is created.It should also be noted that the calibration of profile blank 201 does not involve any change in its wall thickness. The thickness of the walls of the profile blank corresponds to the wall thickness of the calibrated profile. The now calibrated profile can then be used for further applications. List of reference symbols

[0044] 1 Profile blank 2 Wall 3 Element 4 Cavity 5 Press tool 6 Surface 7 Surface 8 Surface 9 Surface 10 Surface 11 Surface 12 Surface 13 Surface 14 Punch 15 Punch 16 Punch 17 Punch 101 Profile blank 102 Wall 103 Element 104 Cavity 105 Press tool 106 Surface 107 Surface 108 Surface 109 Surface 110 Surface 111 Surface 112 Surface 113 Surface 114 Punch 115 Punch 116 Punch 117 Punch 118 Mandrel 119 Mandrel 120 Hollow chamber 121 Hollow chamber 122 Partition wall 123Drive element 124Leg 125Leg 126Support element 127Support element 201Profile blank 202Wall 203Element 204Cavity 205Press tool 206Surface 207Surface 208Surface 209Surface 210Surface 211Surface 212Surface 213Surface 214Punch 215Punch 216Punch 217Punch 218Mandrel 219Mandrel 220Hollow chamber 221Hollow chamber 222Partition wall 223Drive element 224Leg 225Leg 226Counter element 227Counter element 228Hollow chamber 229Hollow chamber 230Hollow chamber 231Hollow chamber 232Partition 233Partition 234Partition 235Partition 236Thorn 237Thorn 238Thorn 239Thorn

Claims

1. Method for calibrating a metal profile blank (1; 101; 201) which has at least one solid wall (2; 102; 202), having the following method steps: a) providing a metal profile blank (1; 101; 201) which has at least one element (3; 103; 203) with a longitudinal extent, a transverse extent and a vertical extent, b) inserting at least one end region of the element of the profile blank (1; 101; 201) into a cavity (4; 104; 204) of an open pressing tool (5; 105; 205), c) closing the pressing tool (5; 105; 205) in such a way that surfaces (6, 7; 106, 107; 206, 207) of the pressing tool (5; 105; 205) are displaced in a main closing direction perpendicular to the longitudinal extent of the profile blank (1; 101; 201) until they come to lie against a pair of surfaces (8, 9; 108, 109; 208, 209), which are situated opposite one another at a distance, of the at least one end region of the element (3; 103; 203) of the profile blank (1; 101; 201) to be calibrated, d) closing the pressing tool (5; 105; 205) further in the main direction, e) closing the pressing tool (5; 105; 205) in a secondary direction perpendicular to the main direction and to the longitudinal extent of the profile blank (1; 101; 201) until surfaces (10, 11; 110, 111; 210, 211) of the pressing tool come to lie against surfaces (12, 13; 112, 113; 212, 213) of the at least one end region of the element (3; 103; 203) of the profile blank (1; 101; 201) to be calibrated, f) closing the pressing tool (5; 105; 205) further in the secondary direction, g) opening the pressing tool (5; 105; 205), h) removing the profile blank (1; 101; 201) which has now been calibrated to the final profile, characterized in that, in step d), as a result of compression, deformation takes place in the at least one end region of the element (3; 103; 203) of the profile blank (1; 101; 201) and bending of the element of the profile blank (1; 101; 201) takes place in the secondary direction perpendicular to the main direction and to the longitudinal extent of the profile blank (1; 101; 201) and, in step f), plastic deformation, generated by compression, of the profile blank (1; 101; 201) takes place in the main direction or secondary direction so as to reduce or eliminate the bending generated in step d).

2. Method according to Claim 1, characterized in that a profile blank (1; 101; 201) composed of an extruded aluminium alloy is used.

3. Method according to Claim 1 or 2, characterized in that a lubricant is applied between the surfaces of the pressing tool that make contact during the compression and the surfaces of the profile blank (1; 101; 201).

4. Method according to Claims 1 to 3, characterized in that during the plastic deformation of the at least one element, overcalibration is performed which compensates for an elastic spring-back action of the element.

5. Method according to Claims 1 to 4, characterized in that the profile blank (1) used is a flat or platelike profile blank, in particular with at least two different surface portions of oppositely situated surfaces, which define different wall thicknesses.

6. Method according to Claims 1 to 4, characterized in that the profile blank (1) used is a hollow chamber profile having at least one hollow chamber, wherein the pressing tool used is a pressing tool with at least one inner tool.

7. Method according to Claim 6, characterized in that a profile blank (1) with at least one hollow chamber having a polygonal, in particular rectangular profile cross section is used.

8. Method according to Claim 6 or 7, characterized in that the at least one inner tool is introduced preferably at least 50 mm into the end region of the at least one hollow chamber of the profile blank (1) prior to the compression.

9. Method according to one of Claims 6 to 8, characterized in that both the height and the width of the end region of the hollow-chamber profile blank decreases by at least 0.2%, in particular by between 0.3% and 5%, during the calibration.