Method for producing a flat plastic component, in particular an underfloor protection element of a motor vehicle, plastic component, and motor vehicle comprising an underfloor protection element
Patent Information
- Application Number
- EP2023821198
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-10
- Filing Date
- 2023-12-06
- Publication Date
- 2025-11-19
AI Technical Summary
Existing methods for producing flat plastic components, such as underbody protection elements for motor vehicles, face challenges in achieving a stabilizing shape during molding with the inclusion of insert elements, particularly when incorporating continuous fibers.
A method involving a compression molding process where a plastic insert element with continuous fibers is heated and arranged in a tool with channel-like recesses, allowing for local deformation and reduction in fiber density to facilitate easier flow of molding compound, which is then distributed through the insert element under increased internal pressure, creating a fiber-reinforced component with integrated ribs and fastening elements.
This method enables the production of flat plastic components with enhanced structural features, such as rib-like elements and a surrounding edge, while reducing the pressure required for molding compound flow, thus improving the shaping and design possibilities of the components.
Smart Images
Figure 1.1
Abstract
Description
[0001] Method for producing a flat plastic component, in particular an underbody protection element of a motor vehicle, plastic component and motor vehicle with an underbody protection element
[0002] DESCRIPTION:
[0003] The invention relates to a method for producing a flat plastic component, in particular an underbody protection element for covering a battery storage unit of a motor vehicle, the method comprising the following steps:
[0004] Providing at least one insert element comprising continuous fibers made of a plastic; providing a molding compound volume made of plastic; heating the at least one insert element; heating the molding compound volume; arranging the molding compound volume and the at least one insert element in a compression molding tool having a tool half facing the insert element, in which a plurality of channel-like depressions are formed; closing the compression molding tool and building up an internal pressure in the compression molding tool.
[0005] Methods for plastic forming are generally known from the prior art, for example from the following publications: DE 697 05 777 T2, DE 10 2018 117 888 A1 and DE 692 22 130 T2.
[0006] The object underlying the invention is seen in specifying a specific manufacturing method for flat plastic components, in particular for an underbody protection element for a motor vehicle, which enables a stabilizing shaping in a simple manner during the forming of the molding compound with the inclusion of an insert element.
[0007] This object is achieved by a method for producing a flat plastic component and by a flat plastic component, in particular an underbody protection element, having the features of the respective independent patent claim. Advantageous embodiments with expedient further developments are specified in the dependent patent claims.
[0008] A method is therefore proposed for producing a flat plastic component, in particular an underbody protection element for covering a battery storage unit of a motor vehicle, the method comprising the following steps:
[0009] Providing at least one plastic insert element comprising continuous fibers;
[0010] Providing a volume of plastic molding compound
[0011] Heating the at least one insert element;
[0012] Heating the molding mass volume;
[0013] Arranging the molding compound volume and the at least one insert element in a compression molding tool having a tool half facing the insert element, in which a plurality of cavities are formed;
[0014] Closing the compression mold and building up internal pressure in the compression mold.
[0015] It is provided that when the internal pressure is built up, the insert element arranged on the relevant tool half, in particular adjacent to it, is draped locally in the region of the cavities, so that the insert element is partially pressed into a relevant cavity of the tool half and deformed, with at least partial local reduction of a fiber density of the insert element; and that the internal pressure in the mold is further increased, so that molding compound in the region of the deformed insert element, which is more permeable due to the reduced fiber density, is pressed through the locally at least partially structurally weakened insert element and is distributed in the cavity, in particular along the insert element.
[0016] When the insert element is draped, it is deformed or curved in the direction of the cavity in certain areas below the cavities provided in one tool half, which can also be called depressions. This deliberately induced deformation achieves a reduction in the fiber volume content or fiber density, so that the flow or pressing through of molding compound is facilitated or can be carried out at a lower pressing pressure. Draping usually takes place over the entire length of a cavity, but can also be specifically induced at selected points in the cavity. For example, intersection areas of cavities or depressions are particularly suitable for draping, whereby molding material pressed through in the area of the intersections can then spread out into the cavities or depressions, although it is present outside the intersection area on or along the insert element.In other words, draping can bring about a greater reduction in fiber density in certain areas than in other areas, so that in those places or areas with the most pronounced reduction in fiber density or fiber volume content, the molding compound flows or passes through the insert element more easily.
[0017] The molding compound volume can be an unformed molding compound volume that is initially distributed over a large area when the compression molding tool is closed. Alternatively, the molding compound volume and the at least one insert element can also be provided as prefabricated semi-finished products, for example, as plate-like semi-finished products. Furthermore, it is conceivable for the insert element and the molding compound volume to be connected to one another before insertion into the compression molding tool, so that they can be provided together as a prefabricated semi-finished product, in particular as a plate-like semi-finished product.
[0018] In this process, the cavities of the mold half can be designed as point-like or / and channel-like. This makes it possible, for example, to form more point-like fastening elements, support sections, and / or elongated rib sections.
[0019] In this method, during or after the closing of the compression molding tool, any air present in the channel-like cavities, in particular the channel-like cavities, can be at least temporarily extracted, creating a negative pressure in the cavities that supports the draping of the insert element and the pressing of the molding compound into the cavities. This facilitates complete filling of the cavities, especially when the molding compound is only pressed through the insert element at specific points, such as the intersection areas of cavities, and the molding compound is intended to flow into the intersecting cavities from such a point.
[0020] In the method, the molding compound can be pressed from a first side of the insert element to a second side of the insert element at several structurally weakened passage points (reduced fiber density or reduced fiber volume content) of the insert element, wherein the molding compound is distributed from a structurally weakened passage point on the second side of the insert element into a respective cavity or depression of the tool half. For example, several intersection points of cavities can be provided as passage points. In this case, a type of rib structure with intersecting rib sections can be created, in particular on the insert element, wherein the rib structure is materially bonded to the molding compound on the other side of the insert element, in particular at the passage points.
[0021] In the method, a first insert element and a second insert element with a volume of molding compound accommodated therebetween can be arranged in the compression molding tool, wherein during compression molding the first insert element and the second insert element are brought into direct contact with one another at least in sections, with the molding compound being completely displaced in sections. This makes it possible for the finished plastic component to also have regions that are formed only by the interconnected insert elements, which expands the possibilities for shaping and design. In the method, a peripheral edge of the molded plastic component can be produced from the molding compound in such a way that the at least one insert element is arranged within the peripheral edge made of molding compound material. It can also be said that the insert element is embedded peripherally in formed molding compound.
[0022] The method may also include opening the compression mold and removing the finished, formed plastic component, which has several molded plastic elements, in particular ribs and / or fastening elements, made of molding compound material on one side. The ribs present on one side of the insert element are created by the molding compound material pressed through from the other side, which has spread into the recesses starting from the penetration points.
[0023] In the process, the insert element can be a UD tape or an organic sheet or a GMT element.
[0024] Also proposed is a flat plastic component, in particular an underbody protection element for covering a battery storage unit of a motor vehicle, comprising a fiber-reinforced insert layer and formed plastic structures arranged on two sides of the insert layer, wherein the plastic structure on a first side of the insert layer is a substantially continuous, flat plastic layer, and wherein the plastic structure on a second side of the insert layer has a plurality of protruding, in particular rib-like plastic elements which are integrally formed with the flat plastic layer at a plurality of locations through the insert layer and which are arranged outside these locations on the second side of the insert layer.
[0025] Such a plastic component or underbody protection element can be manufactured, in particular, using the method described above. Furthermore, the plastic component can have structural features already mentioned above with regard to the method, such as, for example, a peripheral edge made of the same plastic as the plastic structures.
[0026] In a motor vehicle with at least partially electric drive and a battery storage device arranged below a passenger cell, the battery storage device can be covered by such an underbody protection element, the rib-like plastic elements of which face the battery storage device.
[0027] Further advantages and details of the invention will become apparent from the following description of embodiments with reference to the figures.
[0028] Fig. 1 shows a method for producing a flat plastic component using simplified and schematic sectional views in the partial figures A) to D);
[0029] Fig. 2 In the partial figures A) and B) enlarged sectional views of process steps, in particular a draping of an insert element and a beginning pressing through of molding compound;
[0030] Fig. 3 is a simplified and schematic sectional view of a plastic component with two insert elements;
[0031] Fig. 4 is a simplified plan view of an underrun protection device for a motor vehicle;
[0032] Fig. 5 a simplified and schematic perspective view of rib structures of an underbody protection element
[0033] Fig. 6 shows a simplified and schematic representation of an intersection area of cavities or depressions and a change in fiber orientation during draping of an insert element. In Fig. 1, sub-figures A) to D) illustrate, using simplified and schematic sectional views, a method 500 for producing a flat plastic component, in particular an underbody protection element for a motor vehicle.
[0034] According to Figure 1A, in a first step S501, at least one plastic insert element 10 comprising continuous fibers is provided. Furthermore, a molding compound volume 12 is provided. Figure 1 also includes a step S502 for heating the at least one insert element 10 and for heating the plastic molding compound volume 12, which is exemplary here in an unformed state. As already mentioned in the introduction, the insert element 10 and the molding compound volume can also be provided as preformed, in particular plate-like, semi-finished products.
[0035] According to a step S503 shown in Fig. 1B, the molding compound volume 12 and the at least one insert element 10 are arranged in a compression molding tool 14. The compression molding tool has two tool halves 14-1 and 14-2. A plurality of cavities 16, in particular channel-like cavities, are formed in the tool half 14-2 facing the insert element 10.
[0036] In Fig. 1 C), step S504 illustrates closing the compression molding tool 14 and building up an internal pressure in the compression molding tool 14. As the internal pressure builds up, the molding compound volume 14, which in this example is still unformed, is distributed in the compression molding tool 14. Furthermore, according to a step S505, the insert element 10 arranged on the relevant tool half 14-2, in particular adjacent thereto, is locally draped in the region of the cavities 16. In this process, the insert element 10 is partially pressed into a relevant cavity 16 of the tool half 14-2 and deformed. In particular, the insert element 10 is locally curved in the region of the cavities 16, in particular deformed convexly toward the cavity.
[0037] Fig. 1 D illustrates a step S506 in which the internal pressure in the mold 14 is further increased, so that molding compound 12 is pressed through the locally at least partially structurally weakened insert element 10 in the region of the deformed insert element 10 and is distributed in the particularly channel-like cavity 16 along the insert element 10.
[0038] Accordingly, a flat plastic component 18 or an underbody protection element has been produced in the compression molding tool 14, which is shown in simplified and schematic form in Fig. 1E. The flat plastic component 18 thus has a fiber-reinforced insert layer 10. Formed plastic structures 20 are formed on two sides of the insert layer 10. The plastic structure 20-1 on a first, here lower, side of the insert layer 10 is a substantially continuous, flat plastic layer 22. The plastic structure 20-2 on a second, here upper, side of the insert layer 10 has a plurality of protruding, in particular rib-like, plastic elements 24, which are integrally formed with the flat plastic layer 22 at a plurality of locations 26 through the insert layer 10. Outside of these locations 26, the plastic elements 24 are arranged on the second side of the insert layer 10.
[0039] A peripheral edge 28 of the molded plastic component 18 is made of the molding compound, wherein the at least one insert element 10 is arranged within the peripheral edge 28 made of molding compound material.
[0040] According to an optional step S507, during closing (S504) or after closing the compression molding tool 14, air present in the channel-like cavities 16, in particular, can be extracted, so that a negative pressure prevails in the cavities 16, which supports the draping (S505) of the insert element 10 and the pressing of molding compound 12 into the cavities 16. The extraction of air is illustrated in Figs. 2A and 2B by a white contour arrow V.
[0041] Fig. 2 shows a simplified and schematic illustration of the draping of the insert element 10 in the region of a recess 16 of the tool half 14-2. Fig. 2A shows a snapshot that corresponds approximately to step S504 in Fig. 1C. As already explained above, an internal pressure is built up in the compression molding tool 14, wherein the molding compound volume 12 is distributed in the compression molding tool 14. Furthermore, according to step S504, the insert element 10 arranged on the respective tool half 14-2, in particular resting thereon, is locally draped in the region of the cavities 16. As can be seen from the view in Fig. 2A, the insert element 10 is partially pressed into a respective cavity 16 of the tool half 14-2 and deformed. In particular, the insert element 10 is locally curved in the region of the cavities 16, in particular deformed convexly towards the cavity 16. This draping takes place with at least partial local reduction of fiber density ora fiber volume content of the insert element 10. For purely illustrative purposes, Fig. 2A also shows a thickness DE of the insert element 10, which can also change due to draping.
[0042] When the insert element 10 is draped in the region of a cavity 16, fibers 10f of the insert element 10 can be deformed and displaced from their original position in a substantially planar insert element 10. This creates one or more structurally weakened passages 26 locally on the insert element 10. Accordingly, the molding compound 12 can be pressed through these passages 26 to a second side of the insert element 10, wherein the molding compound 12 is distributed starting from a structurally weakened passage 26 on the second side of the insert element in the respective cavity 16 of the tool half 14-2. This can also be understood as step S506 of the method, which is shown in simplified form in Fig. 2B.
[0043] Fig. 3 illustrates, in a simplified sectional view, a plastic component 18 having an optional structure. According to this option, at the beginning of the method 500, a first insert element 10-1 and a second insert element 10-2 with a molding compound volume 12 accommodated therebetween can be arranged in the compression molding tool 14. During compression molding, which was described above with reference to Figs. 1 and 2, the first insert element 10-1 and the second insert element 10-2 are brought into direct contact with one another at least in sections, with the molding compound 12 being completely displaced in sections. This can be referred to as the connecting region 30 of the two insert elements 10-1 and 10-2. For the plastic component 18 with the connecting section 30, reference can also be made to the above description of Fig. 1E, since identical structural parts have already been described there.
[0044] The draping of the insert element 10 can be carried out particularly well if the cavity 16 has a sufficiently large clear width, so that the insert element 10 has sufficient space to be deformed or curved in the direction of the recess 16. It has been shown that a clear width of, for example, 4 to 8 millimeters is sufficient to enable the draping of the insert element 10. If the cavity 16 has a smaller clear width, the deformation of the insert element 10 occurring during draping is not sufficient to press the molding compound through the insert element 10, especially in the case of flat plastic components.
[0045] It should be noted that a cavity 16 does not need to have a sufficient clear width along its entire length. Rather, in a cavity 16 with a length of several centimeters, the clear width can be selected to be sufficiently large in a central area so that the molding compound material can be pressed through the draped insert element 10. Starting from this central area, the molding compound material can then be distributed within the cavity 16, even if it has a smaller clear width. The molding compound material pressed through the central area is then distributed over the insert element 10.
[0046] Fig. 4 shows a simplified and schematic plan view of an underbody protection element 40 as an example of a finished, flat plastic component 18 produced by the method 500 described above. The illustration shows the plastic structures 20-2 described above with reference to Fig. 1E, particularly in the form of ribs 24. The ribs 24 can be aligned differently relative to one another, for example, orthogonally or star-shaped. The insert element 10 is illustrated in this view of Fig. 4 as a dotted surface. The ribs 24 protrude from this surface. The insert element 10 is enclosed by a peripheral edge 28 made of the same plastic material as the ribs 24.
[0047] Fig. 5 shows a simplified and schematic perspective view as a section of an underbody protection element 40. The ribs 24 arranged on the insert element 10 are visible. With such a structure with longitudinal ribs 24I and transverse ribs 24q, the draping of the insert element 10 during the method 500 described above can take place in particular in the intersection areas of the longitudinal and transverse ribs 24I, 24q. In order to be able to produce such rib structures, the mold half 14-2 described above has correspondingly designed, i.e., intersecting, longitudinal and transverse recesses, wherein the passage points 26 for the molding compound material are created in particular in the intersection areas of the longitudinal and transverse recesses, in which the insert element 10 has sufficient space to deform.
[0048] Such an intersection region of a longitudinal recess 161 and a transverse recess 16q is shown in simplified form in Fig. 6. The view of Fig. 6A shows the intersection region with the non-draped insert element 10 and a simplified illustration of the course of fibers 10f in the insert element 10 as an orthogonal grid. The fiber density or the fiber volume content is essentially constant in such a state.
[0049] The view in Fig. 6B shows the insert element 10 after and during draping due to the internal pressure in the mold. The deformation or bulging of the insert element 10 under the cavity 16 leads to a lower fiber volume content or a reduced fiber density. Maximum deformation of the insert element 10 occurs in the intersection area, so that the molding compound material is pressed through in this area at a lower internal pressure.
[0050] In other words, by draping in certain areas, such as an intersection area, a greater reduction in fiber density can be brought about than in other areas, so that in those places or areas with the most pronounced reduction in fiber density or fiber volume content, the molding compound flows or passes through the insert element more easily.
Claims
PATENT CLAIMS:
1. A method (500) for producing a flat plastic component (18), in particular an underbody protection element (40) for covering a battery storage unit of a motor vehicle, the method (500) comprising the following steps: Providing (S501) at least one insert element (10) made of plastic comprising continuous fibers; Providing (S501) a molding compound volume (12) made of plastic; heating (S502) the at least one insert element (10); heating (S502) the molding compound volume (12); Arranging (S503) the molding compound volume (12) and the at least one insert element (10) in a compression molding tool (14) which has a tool half (14-2) facing the insert element (10) and in which a plurality of cavities (16) are formed; Closing (S504) the compression molding tool (14) and building up an internal pressure in the compression molding tool (14); characterized in that, when the internal pressure is built up, the insert element (10) arranged on the respective tool half (14-2), in particular resting thereon, is locally draped (S505) in the region of the cavities (16), so that the insert element (10) is partially pressed into a respective cavity (16) of the tool half (14-2) and deformed, with at least partial local reduction of a fiber density of the insert element (10); Increasing the internal pressure in the mold (14) so that molding compound (12) in the region of the deformed insert element (10), which is more permeable due to the reduced fiber density, is pressed (S506) through the locally at least partially structurally weakened insert element (10) and is distributed in the cavity (16), in particular along the insert element (10).
2. Method (500) according to claim 1, wherein the cavities (16) of the respective tool half (14-2) are designed in a point-like and / or channel-like manner.
3. Method (500) according to claim 1 or 2, wherein during the closing (S504) or after the closing (S504) of the compression molding tool (14) air present in the in particular channel-like cavities (16) is sucked out (S507), so that a negative pressure prevails in the cavities (16), which supports the draping of the insert element (10) and the pressing of molding compound (12) into the cavities (16).
4. Method (500) according to one of the preceding claims, wherein the molding compound (12) is pressed (S506) from a first side of the insert element (10) at a plurality of structurally weakened passage points (26) of the insert element (10) to a second side of the insert element (10), wherein the molding compound (12) is distributed in a respective cavity (16) of the tool half (14-2) from a structurally weakened passage point (26) on the second side of the insert element (10).
5. Method (500) according to one of the preceding claims, wherein a first insert element (10-1) and a second insert element (10-2) with a pressing compound volume (12) accommodated therebetween are arranged in the compression molding tool (14), and wherein during compression molding the first insert element (10-1) and the second insert element (10-2) are brought into direct contact with one another at least in sections, with the pressing compound (12) being completely displaced in sections.
6. Method (500) according to one of the preceding claims, wherein a peripheral edge (28) of the molded plastic component (18) is made from the molding compound (12) such that the at least one insert element (10) is arranged within the peripheral edge (28) made of molding compound material (12).
7. The method (500) according to any one of the preceding claims, further comprising opening the compression molding tool (14) and removing taking the finished, formed plastic component (18) which has on one side a plurality of formed plastic elements (24), in particular ribs (24) and / or fastening elements, made of molding compound material (12).
8. Method (500) according to one of the preceding claims, wherein the insert element (10) is a UD tape or an organic sheet or a GMT element.
9. Flat plastic component (18), in particular an underbody protection element (40) for covering a battery storage unit of a motor vehicle, with a fiber-reinforced insert layer (10) and formed plastic structures (20-1, 20-2) arranged on two sides of the insert layer (10), wherein the plastic structure (20-1) on a first side of the insert layer (10) is a substantially continuous, flat plastic layer (22), and wherein the plastic structure (20-2) has on a second side of the insert layer (10) a plurality of projecting, in particular rib-like plastic elements (24) which are integrally formed with the flat plastic layer (22) at a plurality of locations (26) through the insert layer (10) and which are arranged outside these locations (26) on the second side of the insert layer (10).
10. Motor vehicle with at least partially electric drive and a battery storage device arranged below a passenger compartment, wherein the battery storage device is covered by an underbody protection element (40) according to claim 9, the rib-like plastic elements (24) of which face the battery storage device.