METHOD FOR MANUFACTURING COMPONENTS WITH A BENDING PORT AND SUCH A COMPONENT

Description

[0001] The invention relates to a method for manufacturing components, in particular wheel arch liners for motor vehicles, in which the component is manufactured in a spread or unfolded form and is subsequently folded into a curved or inverted form, wherein the material thickness of the component decreases in a region of a bending point compared to the material thickness of an adjacent region. The invention further relates to a component manufactured by this method. State of the art

[0002] Such processes are already familiar from manufacturing technology; for example, plastic components are produced using injection molding or compression molding. However, if the components have strong curves or an omega shape, several parts are often required because the injected plastic cannot adequately fill molds with strong curves. Handling multiple parts leads to more complex assembly and requires more space on the processing line in the assembly hall, as well as multiple part numbers for management. The production of multi-part systems therefore results in considerable logistical effort, which is associated with costs. Furthermore, expensive slides often have to be attached to the joints of the multiple components to join them together to form a curved part.

[0003] Methods for manufacturing one-piece components with curves are also known. However, these one-piece curved components are often not stackable, or not stackable efficiently, because a significant amount of space remains unused between the outside of one component and the inside of the next, and the reduced packing density and / or the need for more or larger transport boxes greatly increase transport costs.

[0004] Alternatively, the packing density of curved components can be improved by incorporating a classic film hinge into the component. This allows the component to be opened at the film hinge, thus enabling better stacking for transport. Furthermore, the film hinge allows the component to be manufactured in one piece within a single mold. However, a common problem, especially with injection molding, is that a bottleneck often develops at the film hinge, preventing the plastic from being optimally injected into the cavity behind it. Such a bottleneck should therefore be avoided in injection molding processes through improved component design. Additionally, the classic film hinge does not exhibit optimal flexural behavior, as the material is very thin at the flex point.This often leads to material weakening, cracks or white fracture at the bending point, which can also lead to material failure and separation of the individual parts of the curved component.

[0005] From DE 10 2006 054 172 B4, a method for manufacturing curved, self-supporting components is known, in which plate-like single- or multi-layer semi-finished products are deformed, particularly in forming tools, and brought into the shapes of the curved final component, and the pre-formed individual elements are only brought into the final curved component shape at the installation site, wherein the semi-finished products are pre-formed into connected individual elements. The components of the patent specification consist of several layers, wherein the core layer is significantly thinned or omitted at the connection point of the connected individual elements.

[0006] DE 10 2009 057 939 A1 discloses an underbody panel for a motor vehicle comprising two areas designed for different underbody protection requirements. BASF: "Dimensioning of film hinges", May 30, 2014 (2014-05-30), XP055712902, deals with the dimensioning of film hinges. Description of the invention: Problem, solution, advantages

[0007] The present invention is based on the objective of manufacturing a component, in particular a curved or partially curved component, in such a way that the component can be folded or bent into its final shape in a region of the bending point without weakening the material at the bending point or even causing cracks or white fracture. Furthermore, constrictions in the curved component are to be avoided so that it can, for example, be manufactured without restrictions using conventional injection molding processes.

[0008] To solve this problem, the present invention provides a method for manufacturing components, in particular curved or partially curved components, especially wheel arch liners for motor vehicles, in which the component is manufactured in a spread or unfolded form and is subsequently folded or bent into a curved or folded shape. The component is formed such that the material thickness of the curved component decreases in a region of a bend compared to the material thickness of an adjacent region. Specifically, the material thickness in the region of the bend is reduced by 40% to 60%, preferably by 45% to 55%, and particularly by about 50%, of the material thickness of the adjacent region.The width of the bending point area is formed to be twice to thirty times, preferably five to twenty times, particularly preferably ten to twelve times, the thickness of the material of the adjacent area, wherein an area of ​​constant material thickness is formed in the bending point area, and wherein the area of ​​constant material thickness is formed with minimal material thickness.

[0009] A curved or arched component is a component that exhibits a curvature or arch in one or more directions, wherein, in the case of multiple curvatures or arches, these are preferably bent towards each other, i.e., have the same sign. The curvatures or arches may have different radii of curvature or arch radii.

[0010] The spread or unfolded form is the shape in which the component is manufactured, i.e., the tool position in the form of the cavity of the tool mold. In the spread or unfolded form, the component is elongated, with the direction of curvature preferably inverted in the area of ​​the bend, meaning that the center of the circle of the radius of curvature lies on the opposite side of the component than in the curved state. The component can be of any shape and, apart from the area of ​​the bend, can be formed, for example, from curved or arched sections or from at least two linear sections.

[0011] Here, the bending point refers to the area of ​​the component where the curvature changes during folding into the curved state, with the material thickness decreasing and increasing again in the bending point. The bending point encompasses the entire area of ​​the decrease and increase in material thickness along the longitudinal direction of the bend, starting from the material thickness of the adjacent area on one side and ending at the point where the material thickness of the adjacent area is reached again on the other side.

[0012] The curved or folded shape refers to the shape of the component after folding or bending at the bending point. This is preferably the final shape of the component, or the shape of the component that was originally designed, and the shape in which the component is further processed or assembled, i.e., the installation position. In the method according to the invention, the final shape of the component is therefore not produced in the forming tool, as this is only achieved at a later point in time by folding or bending the component.

[0013] Folding, inverting, or bending at a later point in time means that the change in shape of the component does not occur during or directly after its manufacture in a spread, unfolded, or stretched form, but rather that one or more process steps may take place in between, such as storage, packaging, or transport of the component in a spread, unfolded, or stretched form. Therefore, the manufacturing location is usually not the location where the component is folded or bent.

[0014] The areas adjacent to the bend are also referred to as adjacent areas. These are the parts of the component directly connected to the bend, but located outside the area of ​​decreasing and increasing material thickness. The material thickness of the adjacent areas is always greater than the material thickness at the bend. However, in more distant areas, the material thickness may again decrease and / or increase.

[0015] The material thickness refers to the thickness or height of the material (in cross-section) at the respective point. According to the invention, the minimum material thickness in the area of ​​the bend is reduced by 40% to 60%, preferably by 45% to 55%, and particularly preferably by about 50%, compared to the material thickness of the adjacent area. The comparison here is between the minimum material thickness in the area of ​​the bend, i.e., the area of ​​the bend where the thinnest material thickness is achieved, and the maximum material thickness in the adjacent areas. Beyond these adjacent areas, the material thickness can vary, for example, in other areas of the component, i.e., it can decrease or increase again. Preferably, the maximum material thickness even decreases slightly beyond these adjacent areas, since the adjacent areas are manufactured with a greater material thickness.

[0016] The decrease in material thickness from the adjacent areas to the minimum thickness at the bend is continuous, meaning there are no abrupt changes or steps in thickness. The curvature of the top and bottom surfaces of the component at the bend is formed with a similar radius of curvature, meaning that the top and bottom surfaces of the component remain almost parallel at the bend. This prevents a discontinuity in material thickness and therefore a gradual or continuous transition in thickness at the bend down to the minimum thickness.

[0017] This gradual material thickness transition from a thicker material in the adjacent areas to a material thickness in the range of 40% to 60%, preferably 45% to 55%, and particularly preferably about 50%, of the material thickness in the adjacent areas offers several advantages. A wider bending area allows for better stress distribution during bending or folding, resulting in a more harmonious stress distribution and thus a lower risk of fractures or cracks. This also prevents the white fracture often observed in plastics. Furthermore, in the inventive method, unlike conventional injection molding processes with very thin film hinges, no bottlenecks occur in the mold when injecting the plastic into the mold.This allows the plastic to flow more evenly into the mold, reducing the risk of blockages, for example at the narrowest point. This also improves the plastic's flow behavior during the injection molding process. Since a stable hinge is manufactured simultaneously, there's no need for expensive slides, which reduces assembly time and lowers the overall component cost.

[0018] According to the invention, the present method forms the width of the bending area to be two to thirty times, preferably five to twenty times, and particularly preferably ten to twelve times, the thickness of the material of the adjacent area. The bending area can either rise above the adjacent surface or be flush with it, thus forming a flat bending area. The thickness of the material is the distance between the top and bottom surfaces of the component, and therefore the height of the forming tool used to manufacture the component. The large width of the bending area improves the stress distribution when the component is folded or bent, resulting in a significantly more stable component. It is thus an important factor in reducing cracking and white fracture.

[0019] According to the invention, the present method forms a region of constant material thickness in the area of ​​the bend. This region of constant material thickness is an area in which the material thickness does not change, but remains constant at the level of the minimum material thickness. This region of constant material thickness is preferably twice as long as to half as long as the material thickness of the bend. Particularly preferably, the region of constant material thickness has the same width as the thickness of the material in the bend.

[0020] According to the invention, when manufacturing the curved component, the area of ​​constant material thickness is formed with the minimum material thickness. The minimum material thickness is the thinnest material thickness in the area of ​​the bend, i.e., the area where the material thickness has decreased by 40% to 60%, preferably by 45% to 55%, and particularly preferably by about 50%, of the material thickness of the adjacent area. The area with the minimum material thickness is particularly preferably formed in the middle of the bend area. Preferably, the bend area is formed symmetrically, and particularly preferably axially symmetrically, with the area of ​​minimum material thickness lying on the axis of symmetry, i.e., the axis of symmetry passing through the middle of the area of ​​minimum material thickness.

[0021] Preferably, when folded or bent into its curved or folded shape, the component remains open in at least one direction. Thus, the component is not closed in all directions, but preferably open in at least two directions. That is to say, even in its curved or folded shape, the component preferably does not form a closed shape, but remains open.

[0022] Preferably, when bent or folded into its curved or folded shape, the component remains open in the direction opposite the bend. Preferably, however, the component also has further openings that are not opposite the bend. This does not preclude the component from also having an opening on the side of the bend.

[0023] In a preferred process step, when the component is folded or bent into its curved or folded shape, an opening width is created that is shorter than the component's greatest internal width parallel to the opening. The opening width is defined as the distance between opposite sides of the component lying in the plane of the opening. For example, at the end of the component, i.e., where the opening begins, the distance is measured from one edge to the opposite edge. The greatest internal width is determined parallel to the component's opening width, but not in the plane of the opening; rather, it is measured at the level of the component's maximum extent, preferably its maximum internal extent. For circular or elliptical components, this greatest internal width would, for example, correspond to the diameter or twice the major semi-axis, respectively.The crucial factor is that the opening width and the largest internal width are parallel to each other in the component in order to be comparable.

[0024] Preferably, when folding or bending the component into its curved or folded shape, the component is folded or bent in such a way that an undercut, preferably of at least 7°, is created on one side of the component. Particularly preferably, an undercut, preferably of at least 7°, is created on each of the now opposite sides of the component. An undercut is an area of ​​the component which, starting from the edge of the greatest internal width (i.e., the line of the plane of the greatest internal width), is inclined with a curvature towards the opposite side, thus reducing the width of the planes parallel to the plane of the greatest internal width with increasing distance from it. That is, the component curves towards the plane of the greatest internal width, preferably with the previously existing curvature or bulge, whereby the distance between opposite sides decreases in the area of ​​the undercut.The undercut, which extends from the plane of the greatest inner width to the opening, is preferably curved or straight and inclined towards the opposite side of the component, such that the opening width is shorter than the greatest inner width. The component thus tapers again from the plane of the inner width towards the opening and preferably has an omega shape when considering the entire curved or folded form.

[0025] If one now considers a section through the component produced using a preferred process step, which includes both the extent of the largest internal width and is perpendicular to the plane of the internal width and the plane of the opening, the angle of the undercut can be determined. By drawing a straight line in the section plane on one side of the component through the endpoint of the component, i.e., the edge at the opening of the component or its intersection with the section plane, and extending this line to the endpoint of the largest internal width, i.e., the point on the inner wall of the component that is part of the largest internal width and is closest to the previously determined end of the opening, one leg of the angle is obtained. The angle itself is formed by the straight line described above and the tangent to the endpoint of the internal width on the inner wall of the component.The vertex of the angle therefore lies at the endpoint of the inner width, i.e., the point on the inner wall of the component from which the greatest inner width can be measured. This angle described above is preferably at least 7°, but preferably larger.

[0026] Preferably, the spread or unfolded shape of the component is produced by injection molding. In this process, the mold is filled with a suitable thermoplastic or thermoplastic granules. The component is therefore preferably made of plastic, particularly preferably of thermoplastic. The injection molding process offers a significant advantage, especially during injection of the thermoplastic, due to the thicker minimum material thickness of the component produced using the preferred method. This results in considerably less clumping and prevents bottlenecks in the mold, unlike with a conventional film hinge.

[0027] In a preferred method, the component is formed from only one material and / or with a single layer. In contrast to multi-layered forms or the use of multiple materials, this allows for significantly simpler handling and manufacturing of the component. The material itself does not need to be homogeneous, but it is not formed from multiple layers, and / or no film is applied to the top or bottom of the material. Likewise, a reinforcing or filler layer in the middle of the component is not required.

[0028] Preferably, the component is packaged and transported in a spread or unfolded form after manufacturing, and the bending, creasing, or folding of the component into the curved or folded shape is carried out subsequently. Several steps can occur between manufacturing and bending, creasing, or folding the component, such as transporting, packaging, storing, or stacking. In this way, the component can be packaged very efficiently in a spread or unfolded form, and despite this, the significant material thickness in the bending area provides high stability and a low probability of damage at the bending point.

[0029] The invention also relates to a process-formed component, in particular a curved, arched, or partially curved component, specifically a wheel arch liner for motor vehicles. The component has a bending point and, in the area of ​​the bending point, a material thickness that is less than that of an adjacent area. According to the invention, the minimum material thickness in the area of ​​the bending point is 40% to 60%, preferably 45% to 55%, and particularly about 50%, less than the material thickness of the adjacent area. The width of the bending point is formed to be two to thirty times, preferably five to twenty times, and most preferably ten to twelve times, the thickness of the material of the adjacent area.In the area of ​​the bending point, a region of constant material thickness is formed, whereby the region of constant material thickness is formed with minimal material thickness.

[0030] According to the invention, the component has a region of constant material thickness, which is preferably located centrally in the area of ​​the bending point. The material thickness in this region of constant thickness is the minimum material thickness.

[0031] In a preferred embodiment, the component, in its curved or folded form, has an opening in at least one direction, preferably on the side opposite the bend. Preferably, the component, in its curved or folded form, also has an undercut, preferably of at least 7°. Description of the drawings

[0032] Preferred embodiments of a component manufactured using the present method are explained in more detail below with reference to the drawings. They show, in purely schematic form: Figure 1 shows a component in spread or unfolded and curved or folded form, Figure 2 shows a sectional view through the component according to section line AA or A1-A1, Figure 3 shows a sectional view through the component in curved or folded form.

[0033] In Figure 1A component in its spread or unfolded form 100 and a component in its curved or folded form 110 are shown schematically. The bend 10 of the component is located at its midpoint. In its curved or folded form 110, the opening width 11 extends from one edge of the opening 15 to the opposite edge of the opening 15. The largest inner width 12 of the component in its curved or folded form 110 connects the two inner edges of the largest inner width 14 at the point of the component's largest diameter in its curved or folded form 110. The arrows in the diagram show the folding or bending of the component from its spread or unfolded form 100 to its curved or folded form 110. In the curved or folded form, the opening of the width 11 is located on the opposite side of the bend 10.

[0034] Figure 2shows a section according to the section line AA of the component in spread or unfolded form 100 or the section line A1-A1 of the component in curved or folded form 110. Figure 1In the center of the axially symmetric section is the area of ​​a bend 20, with the adjacent area 21 to its right and left. The component has a material thickness 22, which varies along the section. The minimum material thickness 22a is located in the center of the area of ​​a bend 20 in the longitudinal direction of the bend, whereby at the location of the minimum material thickness 22a there exists an area of ​​constant material thickness 24 in which the material thickness 22 does not change. The material thickness of the adjacent area 22b is greater than the minimum material thickness 22a in the center of the area of ​​a bend. The material thickness transition from the material thickness of the adjacent area 22b to the minimum material thickness 22a is continuous. The area of ​​a bend has a similar radius of curvature 25 on its top and bottom surfaces in the component in its curved or folded form 110.The top and bottom surfaces of the area of ​​a bend 20 are therefore similarly curved, with the radius of curvature 25 being constant across the area of ​​the bend. The area of ​​constant material thickness 24 is located in the center of the area of ​​a bend 20 at the point of minimum material thickness 22a. The area of ​​constant material thickness 24 is half as wide as the minimum material thickness 22a is thick. Twice the radius of curvature 25 is 10 times the material thickness of the adjacent area 22b. The minimum material thickness 22a is half the material thickness of the adjacent area 22b. Beyond the adjacent area 21, the material thickness 22 can then decrease or increase again, depending on what is required for the curved component.

[0035] In Figure 3A section through the component in a curved or folded form is shown. The length of the largest internal width 12 extends from one internal edge of the largest internal width 14 to the opposite side of the internal edge of the largest internal width 14. The opening width 11 connects the two edges of the opening 15 on opposite sides. Between the internal edge of the largest internal width 14 and the edge of the opening 15, the distance between the two sides of the component decreases, making the opening width 11 shorter than the largest internal width 12. A so-called undercut is therefore created in this area. The line through the internal edge of the largest internal width 14 and the edge of the opening 15 forms an angle of at least 7° with the tangent at the internal edge of the largest internal width on each side. This angle is the angle of the undercut 17. Reference symbol list

[0036] 100 Component in spread or unfolded form 110 Component in curved or folded form 10 Bending point 11 Opening width 12 Largest inside width 13 Undercut 14 Inner edge of the largest inside width 15 Edge of the opening 16 Tangent at the inner edge of the largest inside width 17 Angle of the undercut 20 Area of ​​a bend 21 Adjacent area 22 Material thickness 22a Minimum material thickness 22b Material thickness of the adjacent area 23 Width of the bend area 24 Area of ​​constant material thickness 25 Radius of curvature of the bend area

Claims

1. Method for manufacturing components, in particular curved or partially curved components, in particular wheel housing liners for motor vehicles, in which the component is manufactured in a spread-out or unfolded form (100) and at a later point in time is formed into a curved or folded form (110), wherein the component has a bending point (10) and, in a region of the bending point (20), a material thickness (22) of the component is reduced or made thinner compared to a material thickness of an adjacent region (22b), characterized in that the minimum material thickness (22a) in the region of the bending point (20) is molded to be 40% to 60%, preferably 45% to 55%, and in particular approximately 50%, thinner than the material thickness of the adjacent region (22b), wherein the width of the region of the bending point (20) is molded to be between twice and thirty times, preferably between five and twenty times, and most preferably between ten and twelve times, of the thickness of the material in the adjacent region (22b), wherein a region of constant material thickness is molded in the region of the bending point (20), and wherein the region of constant material thickness is molded with a minimum material thickness (22a).

2. Method according to claim 1, characterized in that the component is molded in an open state in at least one direction when curved or folded into the curved or folded form (110).

3. Method according to claim 2, characterized in that the component remains open in the direction opposite the bending point (10) when curved or folded into the curved or folded form (110).

4. Method according to claim 2 or 3, characterized in that when the component is curved or folded into the curved or folded form (110), an opening width (11) is formed that is shorter than a maximum inner width (12) of the component parallel to the opening.

5. Method according to claim 4, characterized in that when the component is curved or folded into the curved or folded form (110), the component now has an undercut (13) of at least 7°.

6. Method according to one of the preceding claims, characterized in that the spread or unfolded shape (100) of the component is produced by injection molding.

7. Method according to one of the preceding claims, characterized in that the component is molded from a single material and / or with a single layer.

8. Method according to one of the preceding claims, characterized in that the component is packaged and transported in a spread-out or unfolded form or position (100) after manufacture, and that the curving or folding of the component into the curved or folded form (110) is performed only prior to installation.

9. Component, in particular a curved or partially curved component, in particular a wheel housing liner of motor vehicles, wherein the component has a bending point (10) and, in a region of the bending point (20), a material thickness (22) of the component is reduced compared to a material thickness of an adjacent region (22b), characterized in that, the minimum material thickness (22a) in the region of the bending point (20) has a material thickness (22) that is 40% to 60%, preferably 45% to 55%, and in particular approximately 50%, thinner than the material thickness of the adjacent region (22b), wherein the width of the region of the bending point (20) is molded to be between twice and thirty times, preferably between five and twenty times, and most preferably between ten and twelve times, of the thickness of the material thickness of the adjacent region (22b), wherein a region of constant material thickness is molded in the region of the bending point (20), and wherein the region of constant material thickness is molded with a minimum material thickness (22a).

10. Component according to claim 9, characterized in that the component has a region of constant material thickness, which preferably has a minimum material thickness (22a), and / or that the component has an opening in a curved or folded form (110) in at least one direction, preferably in the direction opposite the bending point (10).

11. Component according to claims 9 to 10, characterized in that the component, in a curved or folded form (110), has an undercut (13), preferably of at least 7°.