Method for producing a fiber-plastic composite component and fiber-plastic composite component

Abstract

Method for producing a fiber-plastic composite component (1), the method comprising the following steps: an embedding step in which reinforcing fibers are embedded in a plastic matrix material to form the fiber-plastic composite component (1), wherein in a mounting area of ​​the component, which during the intended mounting of the component (1) is pressed force-fittingly against a surface of a mounting body by a fastening element, additional reinforcing fibers (2) are embedded in the plastic matrix material in such a way that in the mounting area of ​​the component (1) a volume fraction of the reinforcing fibers is greater than in an area of ​​the component (1) adjacent to the mounting area, wherein the reinforcing fibers are formed in the form of a semi-finished fiber product and the semi-finished fiber product is provided with the additional reinforcing fibers (2) in a section corresponding to the mounting area in such a way that after embedding the semi-finished fiber product provided with the additional reinforcing fibers (2) in the plastic matrix material, the volume fraction of the reinforcing fibers in the mounting area is greater than in the area adjacent to the mounting area, and wherein the semi-finished fiber product is provided with a corrosion protection layer (4) on the section corresponding to the assembly area on a side facing away from the assembly body as intended, by attaching the corrosion protection layer by means of the additional reinforcing fibers (2).

Description

The invention relates to a method for producing a fiber-plastic composite component and to a corresponding fiber-plastic composite component (LCV component).LCV components are generally known in the prior art and are increasingly used in the automobile industry for realizing lightweight constructions.If during assembly it is provided that such LCV components are mounted by a screw connection, measures are necessary to ensure a permanently reliable screw connection. The reason for this is that the fiber-plastic composite has a strong creep behavior, as a result of which the screw connection can lose its prestressing force-so-called setting.In order that the above-mentioned creep behavior of the fiber-plastic composite does not lead to any loosening or loosening of the screw connection, metal bushes for example are glued into the LCV component at locations intended for the assembly in the prior art for passing through the corresponding screw.The principle of such a bonded-in metal bushing is that the prestressing force of the screw connection acts on the metal bushing and the force transmission to the LCV component is taken over by the adhesive that secures the bushing.However, the use and bonding of the explained metal bushes leads to an undesired additional weight of the LCV component and to an increase in the necessary production or assembly steps. For example, the surface of the LCV component must be cleaned before the bonding of the metal bushing, then the adhesive must be applied and allowed to cure.In addition, in the case of a faulty adhesive connection, rigidity losses can occur, which lead to stability problems.DE 10 2013 220 718 A1 discloses a component with a fastening region for a screw connection, wherein the component has a surface with fiber material embedded and bound in a matrix in at least one layer. The fiber material has a fiber course substantially parallel to the surface. In addition, the surface has a fastening opening with a central axis arranged at an angle to the surface, wherein the fastening opening is provided for an internal thread. In the region of the fastening opening, the fiber material lying parallel to the surface is deflected starting from the surface in such a way that the fiber course of the fiber material after the deflection is at an angle to the surface that approaches the direction of the central axis.Further prior art is formed by DE 10 2010 054 935 A1, DE 10 2010 042 128 A1, DE 103 42 183 A1 and DE 100 05 202 A1.Against this background, it is an object of the invention to provide a method for producing an LCV component and a corresponding LCV component which permit direct and secure clamping of the LCV component.This object is achieved by a method according to claim 1 and a fiber-plastic composite component according to claim 7. Preferred embodiments are the subject matter of the dependent claims. The invention is defined by the claims. Aspects of the invention are set out below.One aspect of the invention relates to a method of manufacturing a fiber-plastic composite component as defined in claim 1, the method comprising, inter alia, an embedding step in which reinforcing fibers are embedded in a plastic matrix material to form the fiber-plastic composite component.In an assembly region of the component which, when the component is assembled as intended, is pressed / pressed in a force-fitting manner against a surface of an assembly body by a fastening element which preferably acts directly on the component or its plastic matrix material, according to one aspect of the invention additional reinforcing fibers are embedded in the plastic matrix material in such a way that a volume proportion of the reinforcing fibers is greater in the assembly region of the component than in a region of the component adjoining the assembly region.The plastic matrix material used for producing the component is in particular either a thermosetting matrix material or a thermoplastic matrix material.The mounting region of the component, which is pressed in a force-fit manner against a surface of another mounting body involved by a fastening element when the component is mounted as intended, corresponds in particular to a section of the component, on which the component is clamped for mounting. The mounting region is in particular one on which a passage for a screw or rivet connection is provided.The creep behavior of the fiber-plastic composite component is attributable in particular to the plastic matrix material. Due to the fact that additional reinforcing fibers according to one aspect of the invention are embedded in the plastic matrix material in the mounting region of the component, the volume proportion of the reinforcing fibers in the mounting region is greater than in a region adjoining the mounting region.In other words, the volume proportion of the plastic matrix material is lower in the mounting region.This leads in particular to the component exhibiting a lower creep behavior in the mounting region, for which reason a prestressed fastening element, such as a screw or a rivet, for example, does not loosen in this region or loses its prestressing force only to a slight extent. This effect enables the use of smaller fastening elements or also the working with smaller prestressing forces.In addition, the production method according to one aspect of the invention can produce fiber-plastic composite components which can be fastened by clamping (force-fitting) without additional elements, such as inserts or metal bushes, by fastening elements preferably acting directly on the component or the plastic matrix material.This leads on the one hand to a saving in installation space and on the other hand to a weight reduction of the manufactured component and to a simpler and more cost-effective manufacturing method, because no additional elements need to be provided and the introduction of the additional reinforcing fibers does not require any extensive additional method or process steps.An assembly process of such a component is also simpler, wherein installation space can likewise be saved due to the possibility of using shorter screws.In the method according to the invention, in the embedding step the reinforcing fibers are provided / formed in the form of a semi-finished fiber product and provided with the additional reinforcing fibers at a section corresponding to the mounting region in such a way that after embedding the semi-finished fiber product provided with the additional reinforcing fibers in the plastic matrix material, the volume proportion of the reinforcing fibers in the mounting region is greater than in the region adjoining the mounting region.The semi-finished fibers can be, for example, woven fabrics obtained by weaving fibers, laid scrims formed from one or more layers of parallel, elongated fibers, braids, mats or nonwovens.Depending on the intended use of the fiber-plastic composite component, various types of reinforcing fibers can be used, for example inorganic reinforcing fibers (basalt, boron, glass, ceramic and silica fibers), metallic reinforcing fibers (steel, aluminum, copper, generally metal and metal alloy fibers), organic reinforcing fibers (aramid, carbon, polyester, nylon, polyethylene and plexiglass fibers) and natural fibers (wood and flax fibers).The additional reinforcing fibers can be formed from the same material or a different material as the reinforcing fibers of the semi-finished fiber product.The increase in the volume proportion of the reinforcing fibers in the mounting region of the component can be achieved by a series of measures. For example, additional reinforcing fibers can be bonded to the semi-finished fiber products, prior to their embedding in the plastic matrix material, at the section corresponding to the mounting area.Furthermore, additional fibers are preferably formed in the semi-finished fiber product as seams in the method.Alternatively, in the method according to one aspect of the invention, the additional reinforcing fibers are preferably attached to the semi-finished fiber product as seams by tufting.If the additional reinforcing fibers are attached by additional seams or by tufting the semi-finished fiber product, the additional reinforcing fibers extend in the thickness direction of the semi-finished fiber product and reinforce the component finally produced in this thickness direction.This course of the additional reinforcing fibers is advantageous in particular for the force flow of the prestressing force of a screw or rivet generated for fastening, since the fastening element (screw or rivet) is additionally supported in particular by the additional reinforcing fibers running in the thickness direction.In the method according to the invention, in the embedding step, the semi-finished fiber product is provided with a corrosion protection layer on the section corresponding to the mounting region on a side facing away from the mounting body as intended, in that the corrosion protection layer is fastened to the semi-finished fiber product by the additional reinforcing fibers.The additional corrosion protection layer leads to galvanic separation of a screw or a rivet and the reinforcing fibers of the component. This is advantageous in particular when carbon fibers are used as reinforcing fibers.Particularly preferably, in the method in the embedding step, the semi-finished fiber product is provided on both sides with a corrosion protection layer at the section corresponding to the mounting region, in that both corrosion protection layers are fastened to the semi-finished fiber product by the additional reinforcing fibers.The corrosion protection layer(s) is(are) preferably formed from a glass fibre layer.In the method, a through opening is preferably formed in the mounting region, through which a screw or a rivet can be guided when the component is mounted as intended.A further aspect of the invention relates to a fiber-plastic composite component as defined in claim 7, which comprises, inter alia, reinforcing fibers embedded in a plastic matrix material, wherein the component comprises a mounting region which is pressed against a surface of a mounting body when the component is mounted as intended.The reinforcing fibers are embedded in the plastic matrix material in such a way that a volume proportion of the reinforcing fibers in the mounting region of the component is higher / greater than in a region adjoining the mounting region.A preferred embodiment of the method according to the invention and of a corresponding fiber-plastic composite component are explained below. FIG. 1 schematically shows a sectional view of a component obtained by the method according to the invention; and FIG. 2 schematically shows the manufactured component in its assembled state, wherein the component is fastened to another body via a screw connection.FIG. 1 schematically shows a sectional view of a fiber-plastic composite component 1 according to the invention.The component 1 is produced by embedding reinforcing fibers in a plastic matrix material in an embedding step. The reinforcing fibers can be present, for example, in the form of laid scrims, mats or fabrics, as semi-finished fibers.Before the plastic matrix material is applied for embedding the reinforcing fibers or the reinforcing fibers are impregnated with the plastic matrix material, additional reinforcing fibers 2 are provided on the semi-finished fiber product in a region / section which corresponds to a mounting region of the finally produced component. The section / region of the semi-finished fiber product can in particular be a section / region at which, after completion of the fiber-plastic composite component, a clamping connection in the form of, for example, a rivet connection or screw connection is formed.FIG. 1 shows a through-opening 3 for such a screw or rivet connection. However, this through-opening 3 can also be set by a drill only shortly before assembly and does not necessarily already have to be present or formed during the production of the component.The additional reinforcing fibers 2 can be provided in particular by providing the semi-finished fiber product with additional seams before it is embedded in the plastic matrix material, i.e. by an additional sewing of the semi-finished fiber product.Preferably, these additional reinforcing fibers can also be applied by tufting the semi-finished fiber product.If the additional reinforcing fibers are attached to the semi-finished fiber product by tufting the semi-finished fiber product or by forming additional seams, the additional reinforcing fibers extend in the thickness direction of the semi-finished fiber product and consequently also of the finally produced fiber-plastic composite component 1.Overall, by providing the additional reinforcing fibers 2, the volume proportion of the reinforcing fibers in the fiber-plastic composite component 1 in the mounting region is increased. This has the result that the proportion by volume of the plastic matrix material in the mounting region is lower and the fiber-plastic composite component 1 thus has a lower creep behavior in the mounting region.The additional reinforcing fibers also secure a corrosion protection layer 4 in the mounting region. The corrosion protection layer 4 is preferably a glass fibre layer which is provided in particular when the semi-finished fibre product is produced from carbon fibres.In this case, the corrosion protection layer 4 is preferably provided on a side of the semi-finished fiber product or of the component 1 which, when the component 1 is mounted as intended, faces away from the surface of the mounting body on which the component 1 is mounted as intended.Preferably, however, as shown in FIG. 1, corrosion protection layers 4 can be provided on both sides of the fiber-plastic composite component 1.FIG. 2 shows an arrangement of fiber-plastic composite components according to the invention, which are fastened to one another by means of a screw connection 5.Both components 1, 1' are of identical construction and correspond to the component explained with reference to FIG. 1 and produced by the production method according to the invention.In each of the two components 1, 1' a through-opening 3 is formed, into which a screw 5 is inserted and provided with a nut 6 for mounting the component 1, 1'. In addition, washers can also be provided on both sides of the arrangement between a screw head of the screw 5 or between the nut 6 and the components 1, 1'.When the screw 5 is tightened, both components 1, 1' are fastened to one another by a frictional connection (clamping) by the prestressing force of the screw 5.Because a corrosion protection layer 4 is provided on the surfaces of the components 1 facing the screw 5 or the nut 6, corrosion of the screw 5 does not occur.Moreover, the configuration of the components 1 according to the invention ensures that the screw does not loosen because of the reduced creep behavior of the plastic matrix material used.

Claims

Method for producing a fiber-plastic composite component (1), the method having the following steps: an embedding step in which reinforcing fibers are embedded in a plastic matrix material for forming the fiber-plastic composite component (1), wherein in an assembly region of the component which is pressed in a force-fitting manner against a surface of a mounting body by a fastening element when the component (1) is mounted as intended, additional reinforcing fibers (2) are embedded in the plastic matrix material in such a way that in the assembly region of the component (1) a volume proportion of the reinforcing fibers is greater than in a region of the component (1) adjoining the assembly region, wherein the reinforcing fibers are formed in the form of a semi-finished fiber product and the semi-finished fiber product is provided with the additional reinforcing fibers (2) at a section corresponding to the mounting region in such a way that after embedding the semi-finished fiber product provided with the additional reinforcing fibers (2) in the plastic matrix material, the proportion by volume of the reinforcing fibers in the mounting region is greater than in the region adjoining the mounting region, and wherein the semi-finished fiber product is provided with a corrosion protection layer (4) on a side facing away from the mounting body as intended, at the section corresponding to the mounting region, by fastening the corrosion protection layer by the additional reinforcing fibers (2).Method according to claim 1, wherein the additional reinforcing fibers (2) are formed as seams in the semi-finished fiber product.Method according to claim 1, wherein the additional reinforcing fibers (2) are attached to the semi-finished fiber product as seams by tufting.The method according to any one of claims 1 to 3, wherein in the embedding step, the semi-finished fiber product is provided with a corrosion protection layer (4) on both sides at the portion corresponding to the mounting area by attaching both the corrosion protection layers (4) by the additional reinforcing fibers (2).Method according to one of Claims 1 to 4, wherein the corrosion protection layer (4) is a glass fibre layer.Method according to one of the preceding claims, wherein a through-opening (3) is formed in the mounting region, through which a screw or a rivet can be guided when the component is mounted as intended.Fiber-plastic composite component (1) which has reinforcing fibers embedded in a plastic matrix material, wherein the component (1) has a mounting region which, when the component (1) is mounted as intended, is pressed in a force-fitting manner by a fastening element against a surface of a mounting body, the reinforcing fibers are embedded in the plastic matrix material in such a way that a proportion by volume of the reinforcing fibers in the mounting region of the component (1) is greater than in a region adjoining the mounting region, the reinforcing fibers in the form of a semi-finished fiber product are embedded in the plastic matrix material, and the semi-finished fiber product is provided with the additional reinforcing fibers (2) at a portion corresponding to the mounting region in such a way that, in the plastic matrix material, the proportion by volume of the reinforcing fibers in the mounting region is greater than in the region adjoining the mounting region, the semi-finished fiber product is provided on the section corresponding to the mounting region on a side facing away from the mounting body as intended with a corrosion protection layer (4), and wherein the corrosion protection layer is fastened by the additional reinforcing fibers (2).

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