Fiber composite component and methods for manufacturing a fiber composite component

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The integration of a load introduction component with beveled edges and chamfers into fiber composite components addresses the issue of stress peaks and fiber separation, ensuring efficient load distribution and cost-effective manufacturing.

DE102014210506B4Active Publication Date: 2026-05-21BAYERISCHE MOTOREN WERKE AG

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Patent Information

Authority / Receiving Office: DE · DE
Patent Type: Patents
Current Assignee / Owner: BAYERISCHE MOTOREN WERKE AG
Filing Date: 2014-06-03
Publication Date: 2026-05-21

AI Technical Summary

Technical Problem

Existing methods for creating load introduction points in hollow fiber composite components, such as CFRP, result in fiber separation and weakening, leading to stress peaks and costly, complex machining processes.

Method used

A load introduction component with beveled or rounded edges and chamfers is integrated into the fiber profile during manufacturing, allowing load distribution without significant fiber separation and providing smooth transitions, which can be made of high-strength plastic or metal.

Benefits of technology

Enables load-appropriate introduction with minimal post-processing, preventing fiber weakening and stress peaks, while maintaining structural integrity and reducing manufacturing costs.

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Abstract

Fiber composite component (10) comprising a profile part (20) that is a hollow profile part and consists of a plurality of interwoven fibers (25), a load introduction component (40) arranged between the fibers (25) of the profile part (20), and a matrix material (30) in which the fibers (25) of the profile part (20) are embedded, wherein the fiber composite component (10) has an inner contour with an undercut that hinders the removal of a core, wherein the load introduction component (40) represents the undercut when viewed in the longitudinal direction of the hollow profile part, and wherein the load introduction component (40) is provided with chamfers (42), at least one of which is provided on the inner contour of the fiber composite component (10) so that the core can be removed more easily, wherein the chamfers (42) have an angle from an angular range between 5° and 45°.

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Description

[0001] The present invention relates to a fiber composite component and a method for manufacturing a fiber composite component.

[0002] Braided profiles made from the fibers used play a major role in the development of vehicle structures in fiber composite construction, for example, CFRP. Braided profiles allow the given load paths to be efficiently covered.

[0003] After a preform has been woven over a core, it is cured with a plastic matrix and can then be further processed and installed.

[0004] The greatest weight reduction can be achieved by removing the core after the manufacturing process, resulting in a hollow profile. This can be accomplished, for example, with an inflatable plastic core that is completely withdrawn from the component after braiding. The load introduction point, where loads are introduced into such a hollow braided component, is of great importance. While operational loads within the braided component can be optimally and fiber-appropriately distributed by the carbon fibers, the load introduction point usually creates an unwanted stress peak. Examples of such load introduction points include holes for bolting points. These stress peaks can lead to component failure.

[0005] If the profile is hollow, a load application point can usually only be created after removing the core through mechanical post-processing, such as drilling or milling. However, this separates a large area of the carbon fibers that cover the load path, thus significantly weakening the overall component. In addition to the mechanical properties, subsequent machining of the CFRP component is always very expensive. Tool wear is high, and a special fixture may be required for each machining step.

[0006] From DE 10 2013 108 251 A1 a fiber composite body is known which has a layered structure of fibers as well as load introduction components which have a cylindrical inner contour.

[0007] In DE 10 2009 051 459 A1 a fiber composite part is shown which has several layers of fibers, between which reinforcing inserts are arranged.

[0008] From DE 195 24 903 A1 a fiber composite body is known which has wound fibers which, among other things, wrap a metallic end piece.

[0009] In DE 10 2011 087497 A1 a method for manufacturing a fiber composite component is described in which a blow-molded core is used.

[0010] From DE 10 2010 026 018 A1 a rotor blade is known which was manufactured using winding technology.

[0011] DE 10 2011 120 B4 discloses a threaded spindle with an inner core and an outer shell, wherein the shell has a hard-film configuration and the core has a fiber composite material.

[0012] It would therefore be desirable for fiber composite components with a hollow profile structure to have more suitable load introduction points available, while still allowing the use of a lightweight and economical hollow profile.

[0013] It is therefore the object of the present invention to advantageously further develop a fiber composite component and a method for producing a fiber composite component, in particular in such a way that a lightweight and economical fiber composite component, in particular a fiber composite component with a hollow profile, can be produced, wherein load introduction points are provided which enable load introduction in accordance with the load requirements at a reasonable cost and are also lightweight.

[0014] This problem is solved according to the invention by a fiber composite component with the features of claim 1.

[0015] This offers the advantage that, by using a load introduction component, a load introduction point can be created that enables load-appropriate load introduction, while simultaneously avoiding large-scale separation and destruction of fibers. A weakening of the fiber-reinforced composite component is thus prevented.

[0016] Furthermore, the use of the load introduction component makes it possible to arrange the subsequent load introduction directly within the fiber composite component.

[0017] Furthermore, only minimal post-processing is usually required. The loads from the load introduction point can thus be distributed over a large area within the fiber-reinforced composite component. The load introduction component can be woven into the fiber profile section by creating areas during the manufacturing process of the profile section that are covered with a load introduction component and then woven over. This offers the advantage that the load introduction component is encased and thus held in place by the fibers of the profile section. Consequently, the load path from the load introduction component to the profile section is characterized by few stress peaks, as the loads introduced into the structure of the fiber-reinforced composite component via the load introduction component can be distributed over a large area from the load introduction component into the areas surrounding it.

[0018] Beveled or rounded edges facilitate the positioning of the load introduction component between the fibers of the profile section. This is particularly advantageous when the load introduction component is braided with fibers, as it prevents, for example, the fibers from kinking at the edges. Furthermore, it avoids load peaks at the transition to the fiber-reinforced composite section.

[0019] Furthermore, the load introduction component may be designed to have at least one chamfer. Such a chamfer has the advantage of allowing a smooth transition from the areas of the profile section surrounding the load introduction component. The local reinforcement provided by the load introduction component, viewed in the longitudinal direction of a hollow profile, essentially represents an undercut that hinders the removal of a core. The chamfers allow the core to slide more easily through areas with cross-sectional reductions during removal. In addition, smooth transitions are created and step formation is avoided, thereby preventing load peaks and potential component failure.

[0020] Furthermore, the load introduction component may be made of a high-strength plastic or metal. This ensures high stability of the load introduction component.

[0021] Furthermore, it is possible that the load introduction component has at least one hole or at least one threaded hole. This significantly simplifies any necessary rework, as the existing hole or threaded hole only needs to be exposed during the rework process.

[0022] Furthermore, it is conceivable that the load introduction component, for example with regard to its longitudinal cross-section, is at least partially L-shaped, U-shaped, or O-shaped. Such a profile supports the stability of the entire fiber-reinforced composite component in the area of the load introduction component.

[0023] Furthermore, the chamfer can be designed to have an angle between approximately 5° and 30°. The cross-section, for example in the side view of the chamfer, can be configured to extend from one side of the load introduction component to the other, with the chamfer height being less than its length. This allows for particularly smooth transitions and the avoidance of load peaks.

[0024] It is also conceivable that the profile has its maximum height in the areas where fastening points or fasteners are attached, arranged, or, for example, screwed in, and is provided with corresponding chamfers in the adjacent areas, reducing the maximum height of the load-bearing component back to the level of the base surface. This has the advantage that the load-bearing point has sufficient material thickness. At the same time, step formation is avoided, since the material thickness is preferably provided with a smooth transition on all sides by means of the chamfers. In particular, this results in a homogeneous distribution of the force lines from the load-bearing point into the braided or wound profile.

[0025] Furthermore, the height of the load introduction component can be designed to be less than its width. This has the advantage that, after being woven into the profile section, the load introduction component does not cause steps or abrupt changes in cross-section. This also results in smooth transitions.

[0026] It is particularly preferred that the profile section is a hollow profile section. Hollow profile sections enable lightweight yet stable structures. They can therefore be advantageously used as load-bearing structures in car body construction. In this context, the smooth cross-sectional transitions facilitate the insertion and removal of a core to create the hollow profile at the point where the load-bearing component is integrated into the profile section.

[0027] Furthermore, the matrix material can be a thermoplastic or thermoset material. These materials enable a stable and strong bond with the fibers of the profile section. A thermoplastic or thermoset matrix material is advantageously well-suited to connecting or crosslinking a fiber-reinforced profile section with an insert component that is woven into the profile section.

[0028] It is possible that the fibers are carbon fibers. The use of carbon fibers has the advantage that they are ideally suited for creating lightweight structures with high strength.

[0029] Furthermore, the present invention relates to a method for manufacturing a fiber-reinforced composite component. According to this invention, a method for manufacturing a fiber-reinforced composite component is carried out such that the method comprises at least the following steps: - a core is provided, which is a blow-up core; - a load introduction component is arranged on the core, which is provided with chamfers, at least one of which will be provided on an inner contour of the manufactured fiber composite component which has an undercut, wherein the chamfers have an angle from an angular range between 5° and 45°; - the core is braided with fibers to form a profile part, whereby the load introduction component is also braided, such that the load introduction component, viewed in the longitudinal direction of the hollow profile part, represents the undercut; - the fibers of the profile part are embedded in a matrix material; - the core is removed.

[0030] In principle, the same features and advantages as described above in connection with the fiber composite component according to the invention can also be provided or achieved in the inventive method for producing a fiber composite component.

[0031] Furthermore, it is conceivable that the load introduction component is fixed to the core. This is achieved in particular by gluing. By fixing the load introduction component before braiding it into the profile section, it can advantageously be ensured that the load introduction component does not slip during braiding and thus remains in position and exhibits sufficient handling strength for subsequent processes. This allows for higher manufacturing accuracy.

[0032] Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. The drawings show: - Fig. 1 in schematic view a manufacturing process according to the invention for a fiber composite component according to the invention in a schematic sectional view; - Fig. 2 a schematic view of a fiber composite component according to the invention obtained by a method according to the invention for producing a fiber composite component; - Fig. 3 a perspective view of a load introduction component for a fiber composite component according to the invention; and - Fig. 4 an embodiment of a fiber composite component according to the invention obtained by a method according to the invention for producing a fiber composite component.

[0033] Fig. Figure 1 shows in schematic representation the manufacturing process according to the invention of a fiber composite component 10 according to the invention.

[0034] The fiber composite component 10 has a profile part 20 which is embedded in a matrix material 30.

[0035] The profile section 20 consists of fibers 25. In the embodiment of the invention shown here, the fibers 25 are carbon fibers. However, it is generally conceivable that any type of suitable fiber, e.g., glass fibers, could be used for the profile section.

[0036] The matrix material 30 is a thermoplastic material. However, it is also conceivable that the matrix material is a thermosetting material.

[0037] To reinforce the structure of the fiber composite component 10, a load introduction component 40 is provided at a load introduction point. The load introduction component 40 consists of a high-strength plastic or metal and has beveled or rounded edges.

[0038] The height of the load introduction component 40 is less than its width.

[0039] To produce the fiber-reinforced composite component 10, a core, in particular a blow-molded core, is first provided. A load introduction component 40 is then attached to the core. This component can be glued to the core for temporary fixation.

[0040] The core, with the load introduction component 40 attached to it, is then braided with fibers. The load introduction component is thereby integrated into the fiber braid.

[0041] The profile part 20 with the load introduction component 40 woven into it is then overmolded with a matrix material 30, so that the profile part 20 and the load introduction component 40 are connected by the matrix material 30 and are embedded in the matrix material 30.

[0042] The core can then be removed.

[0043] As in Fig. As can be seen in Figure 1, the fiber composite component 10 is a hollow profile, which is created by inserting a core into the hollow profile during the manufacturing of the profile.

[0044] Therefore, the load introduction component 40 is also designed in such a way that the insertion of the core for the creation of the hollow profile is not hindered.

[0045] The core can be, for example, a blow core. To prevent the blow core from being drawn into the blow core tool, the following procedure is used: The insertion of the load introduction component 40 creates an undercut at the local reinforcement point. The transitions from the undisturbed inner contour of the fiber composite component 10 to the disturbed inner contour in the area of the load introduction component 40 are designed with smooth transitions. This is achieved through the special shape of the load introduction component 40.

[0046] To achieve these smooth transitions, the load introduction component 40 has a height h that is less than the width b and the length l of the load introduction component 40. In addition, the load introduction component 40 has rounded corners and edges.

[0047] Furthermore, the load introduction component 40 is provided with chamfers 42, the chamfers being located at the edges and corners of the load introduction component 40. In this context, it is conceivable, for example, that the load introduction component 40 has a circumferential chamfer 42.

[0048] The chamfer 42 has an angle within an angular range of approximately 5° to 45°, here approximately 20°.

[0049] At the same time, the minimum diameter of the blow mold core is not undercut; this can be, for example, on the order of approximately 20 mm. This depends on the profile and nominal diameter.

[0050] The load introduction component 40 can be made of stainless steel and have a load introduction point. This load introduction point can, for example, be in the form of a bore or a threaded bore. Furthermore, the load introduction component 40 can be made of plastic.

[0051] Fig. Figure 2 shows a perspective view of a fiber composite component 10 according to the invention in a detailed view. As shown from Fig. As can be seen in Figure 2, a load introduction component 40, with respect to its longitudinal cross-section in the form of an L-shaped profile, is already embedded in the profile part 20 and the matrix material 30. The load introduction component 40 has several chamfers 42, which enable a smooth transition from the areas of the fiber composite component 10 to the area in which the load introduction component 40 is inserted. However, it is also conceivable that the load introduction component 40 has an essentially U-shaped or O-shaped cross-section with respect to its longitudinal cross-section.

[0052] The load introduction component 40 made of Fig. 2 is shown in perspective in closer detail. Fig. Figure 3 shows the load introduction component 40, which has a total of four load introduction areas 45 into which bores can be drilled. The load introduction component 40 is designed here as an L-shaped profile with several chamfers 42, which have an angle selected from a range of approximately 5° to 30°, here approximately 20°.

[0053] Between the load introduction areas 45, a further section 47 is provided, which serves as a connection between the two load introduction areas 45. Here, a chamfer 42 is also provided in order to reduce the load introduction component 40 from a first height h in the area of the load introduction areas to a reduced height h1.

[0054] As from Fig. As can be seen in Figure 4, the fiber composite component 10 can be a door frame for a motor vehicle. Door hinges or other body parts can be attached to the load introduction component 40. In the Fig. In the case shown in Figure 4, a door frame 50 for a motor vehicle with a hinged door is attached to the door frame 50 in the area of the load introduction component 40 with its pivoting mechanism.

Claims

[1] Fiber composite component (10) comprising a profile part (20) that is a hollow profile part and consists of a plurality of interwoven fibers (25), a load introduction component (40) arranged between the fibers (25) of the profile part (20), and a matrix material (30) in which the fibers (25) of the profile part (20) are embedded, wherein the fiber composite component (10) has an inner contour with an undercut that hinders the removal of a core, wherein the load introduction component (40) represents the undercut when viewed in the longitudinal direction of the hollow profile part, and wherein the load introduction component (40) is provided with chamfers (42), at least one of which is provided on the inner contour of the fiber composite component (10) so that the core can be removed more easily, wherein the chamfers (42) have an angle from an angular range between 5° and 45°. [2] Fiber composite component (10) according to claim 1, characterized by , that the load introduction component (40) is made of a high-strength plastic or of metal. [3] Fiber composite component (10) according to any one of the preceding claims, characterized by , that the height of the load introduction component (40) is less than its width. [4] Fiber composite component (10) according to any one of the preceding claims, characterized by , that the profile part (20) is a hollow profile part. [5] Fiber composite component (10) according to any one of the preceding claims, characterized by , that the matrix material (30) is a thermoplastic or thermosetting material. [6] Fiber composite component (10) according to any one of the preceding claims, characterized by , that the fibers (25) are carbon fibers. [7] Method for producing a fiber composite component (10) by the following steps: - a core is provided, which is a blow-up core, - a load introduction component (40) is arranged on the core, which is provided with chamfers (42), at least one of which will be provided on an inner contour of the manufactured fiber composite component (10) which has an undercut, wherein the chamfers (42) have an angle from an angular range between 5° and 45°, - the core is braided with fibers (25) to form a hollow profile part (20), whereby the load introduction component (40) is also braided, such that the load introduction component (40) represents the undercut when viewed in the longitudinal direction of the hollow profile part, - the fibers (25) of the profile part (20) are embedded in a matrix material (30), - the core is removed. [8] Method according to claim 7, characterized by , that the load introduction component (40) is fixed to the core, in particular by being glued on.