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

Abstract

Method for producing a fiber-plastic composite component (100) which is reinforced in at least one partial area (130, 140) by means of a textile insert (200), comprising the steps: - producing at least one textile insert (200) formed from reinforcing fibers, which comprises a net-like base reinforcement (210) and at least one local additional reinforcement (220) attached thereto; and - Placing the insert (200) in the cavity of an injection mold and carrying out an injection molding process by injecting a plastic matrix material into the closed cavity, wherein the insert (200) is completely embedded in the injected plastic matrix material; characterized in that the net-like base reinforcement (210) is a textile fabric formed from reinforcing fibers with a net structure, and in that at least one fiber roving (220) is used as additional reinforcement, wherein this fiber roving (200) is threaded or woven into the net structure of the base reinforcement (210).

Description

The invention relates to a method for producing a fiber-plastic composite component which is reinforced at least in a partial region by a textile insert according to the preamble of claim 1.DE 10 2012 010 768 A1 describes a structural component for a motor vehicle, in particular in the form of a mounting bracket which can be mounted in the front or rear region of the vehicle, and a method for producing the same. The structural component consists of plastic and is manufactured as a molded part and has at least in partial regions two or more fabric layers (GF, CF), which are injection-molded with a thermoplastic (KU) plastic. Reference is also made in particular to the prior art described in DE 10 2012 010 768 A1.DE 10 2014 201 099 A1 relates to a reinforcing structure for fiber-reinforced components with a carrier layer made of fiber material and a reinforcing system made of fiber material, wherein the reinforcing system is arranged on the carrier layer. The invention furthermore relates to a method for producing a reinforcing structure and for producing a fiber-reinforced component.DE 10 2005 034 400 A1 relates to a device for producing a fiber preform having virtually any surface geometry in the TFP method, wherein a fiber strand can be deposited on a support layer by means of a guide means in virtually any path curve, and the fiber strand can be attached to the support layer by means of at least one fixing thread by means of a sewing head.DE 10 2012 007 005 A1 relates to a steering column arrangement for a vehicle and to a method for producing components for such a steering column arrangement.More particularly, the invention relates to a steering column assembly that is adjustable in length and / or inclination.Proceeding from this prior art, the object of the present invention is to specify a method of the relevant type with which light and loadable fiber-plastic composite components can be produced in a simple manner.This object is achieved by the method according to the invention according to claim 1. Preferred refinements and embodiments of the invention are obtained analogously for both subject matter of the invention from the dependent patent claims, the following description and the figures of the drawing.The method according to the invention comprises the steps:making at least one textile insert comprising reinforcing fibers or formed from reinforcing fibers, in particular long or continuous fibers, which textile insert comprises or has a net-like base reinforcement and at least one local additional reinforcement fastened thereto; andplacing the insert in the cavity of an injection molding tool, closing the tool or the cavity and carrying out an injection molding process by injecting a plastic matrix material into the closed cavity, wherein the insert is completely embedded in the injected plastic matrix material, wherein the net-like base reinforcement is a textile fabric formed from reinforcing fibers and having a net structure, and that at least one fiber roving is used as additional reinforcement, wherein this fiber roving is threaded or woven into the net structure of the base reinforcement.After the injected plastic matrix material has cured, the tool can be opened and the fiber-plastic composite component removed. The fiber-plastic composite component is usually ready for installation, i.e. further post-processing steps are not actually provided.Preferably, all steps and substeps of the method according to the invention are carried out at least partially automatically and in particular fully automatically.A net- or grid-like base reinforcement is understood to mean a more or less coarse- or large-mesh textile fabric with uniform or else non-uniform meshes or openings formed from reinforcing fibers, in particular long- or endless fibers, or fiber roving, which fabric forms a base reinforcement in the relevant component region. These reinforcing fibers are, for example, glass or carbon fibers, although in principle other organic and inorganic fibers are also possible. Preferably, the mesh is rhombic, square or rectangular, which can have a mesh width of 3 mm to 7 mm, preferably of 4 mm to 6 mm and in particular of about 5 mm. The mesh width is the clear distance between the mesh strands or threads measured in the middle of a mesh or opening. The weight per unit area is, for example, only 50 to 100 g / m^2.In particularly stressed component regions (frequently, these are typical failure zones, which can be evaluated, for example, in tests or simulations), additional reinforcements formed from reinforcing fibers, in particular long or endless fibers, are likewise attached to this grid-like base reinforcement, as will be explained in greater detail below. These reinforcing fibers are organic or inorganic fibers, for example glass, carbon, synthetic or natural fibers.Both the net-like base reinforcement and the at least one additional reinforcement attached thereto are preferably dry fiber materials, i.e. fiber materials not preimpregnated with a matrix material. The dry fiber material can, however, be provided with a so-called sizing, which facilitates the later impregnation with plastic matrix material or improves the achievable degree of impregnation. The embedding of the fiber materials takes place in an injection molding process or process, in which the plastic matrix material is injected directly into the cavity of the injection molding tool without the need for an upstream preheating process. The at least one insert can be fixed in the cavity in a manner known per se, for example by means of mandrels or pins. The plastic matrix material is in particular a thermoplastic plastic material. The in particular thermoplastic matrix material can be enriched with short fibers. These short fibers are, for example, glass or carbon fibers, although in principle other organic and inorganic short fibers are also possible. The fiber volume fraction can be up to 30% or more.The grid-like base reinforcement enables good impregnation with the plastic matrix material, even if it is enriched with short fibers. As a result, load-bearing components with thin wall thicknesses and low weight can be produced, wherein additional reinforcement takes place in particularly loaded regions, so that there is virtually double reinforcement in these regions. Potential failure zones are thus partially reinforced. By means of such a targeted reinforcement, lightweight construction potentials can be better exploited and synergistic effects between fibers and matrix can be better utilized. With the method according to the invention, it is therefore possible to produce light and loadable fiber-plastic composite components in a simple process cycle, which also meet high safety requirements (for example in the event of crash loading).It is particularly preferably provided that a planar reinforcing structure is produced with the at least one fiber roving. This means that the one-dimensional fiber roving or roving is arranged or deposited on the net-like base reinforcement in the relevant region in such a way that a two-dimensional reinforcement structure, which functions as an additional reinforcement, is produced.A semi-finished fiber product blank (patch) can also be used as additional reinforcement. Semifinished fiber products are woven fabrics, laid scrims, nonwovens and the like containing reinforcing fibers, in particular long or endless fibers, which in particular have a higher basis weight than the textile fabric used for the net-like base reinforcement. The weight per unit area is, for example. 200 to 300 g / m^2 is preferably a dry semi-finished fibre product. An optimum blank size and shape can be determined, for example, by simulation and / or experiments. A plurality of semi-finished fibre products can be fastened to a net-like base reinforcement, which semi-finished fibre products have the same or different blank shapes and are produced from the same semi-finished fibre product or different semi-finished fibre products.The possibilities explained above for producing or generating an insert or reinforcement insert with a base reinforcement and with at least one local additional reinforcement fastened thereto can also be combined with one another within the scope of the invention. That is to say, an insert used for reinforcing the fiber-plastic composite component to be produced can have a plurality of additional reinforcements, which can also be formed or produced differently.The fiber-plastic composite component according to the invention claimed in the subordinate patent claim is produced by a method according to the invention and reinforced in at least one partial region with a textile insert which is completely embedded in plastic matrix material and formed from reinforcing fibers, wherein the textile insert has a net-like base reinforcement and at least one local additional reinforcement fastened thereto, as described above, wherein at least one fiber roving is provided as additional reinforcement, which is threaded or woven into the net structure of the base reinforcement. Complete embedding is understood to mean that the insert is surrounded by plastic matrix material substantially everywhere, i.e. at all points, and is thus ideally invisible, in particular when using a non-transparent plastic matrix material.It is preferably a mounting frame, in particular a one-piece mounting frame, for at least one heat exchanger to be arranged in the front region of a motor vehicle (such a frame can also be referred to as a motor vehicle mounting frame or as a heat exchanger mounting frame for motor vehicles), wherein the side parts or side straps of this mounting frame are each reinforced with such a textile insert, which have a net-like base reinforcement and at least one local additional reinforcement fastened thereto. Other frame parts (for example the upper chord, the lower chord or the corner regions) can also be reinforced with at least one such textile insert. Preferably, the frame parts reinforced by means of a textile insert have only a wall thickness of between 2 mm and 3 mm.The invention is explained in more detail below in a non-limiting manner on the basis of an exemplary embodiment with reference to the drawing. The features shown in the figures of the drawing and / or explained below can, even if they are separated from certain combinations of features, be general features of the invention and develop the invention. FIG. 1 shows a mounting frame produced according to the invention. FIG. 2 shows a detail of a textile insert which is used to reinforce the mounting frame from FIG. 1. FIG. 3 shows, analogously to FIG. 2, another possible embodiment, not according to the invention, for a textile insert.FIG. 1 shows a frame-like mounting support or mounting frame 100, which is arranged in the front region of a motor vehicle and is provided for receiving at least one heat exchanger (radiator). Further parts, such as for example, can also be attached to the mounting frame 100. Furthermore, the cables may be fastened to headlights, sensors, cable harnesses and the like. The one-piece mounting frame 100 includes an upper frame member 110, a lower frame member 120, and side frame members 130 and 140.The mounting frame 100 is an injection-molded part formed from a fiber-plastic composite and is thus light and resistant. The plastic material used, which can be in particular a thermoplastic plastic material, is mixed with short fibers. Polypropylene (PP), polyamide (PA), polyethylene (PE) or another suitable thermoplastic is preferably used as the plastic material. In addition, textile inserts 200 (see also FIGS. 2 and 3 ) are processed in the side parts 130 and 140 that are particularly stressed in the event of a rear-end collision, as a result of which these side parts 130 and 140 are particularly stable without additional thickening. The side parts 130 and 140 have a wall thickness of only 2 mm to 3 mm, for example. In an analogous manner, the upper frame part or the upper chord 110 and / or the lower frame part or the lower chord 120 can also be formed with at least one such reinforcement.The surrounded regions B are crash-loaded regions in which crash sensors for triggering airbags are fastened. Any component fractures in these regions interfere with the crash signal transmission. These component regions B must therefore be particularly stable, which is accomplished by appropriate configuration of the inserts 200. The reinforcement concept according to the invention is a structural fiber reinforcement, i.e. one which is bound into the component structure, with additional fiber reinforcement formed in regions, which is fundamentally of subsequently applied reinforcement elements, such as, for example. This invention is distinguished from sheet metal reinforcements made of steel sheet or aluminum sheet. The invention ensures the transmission of crash signals in an optimum manner, but uses as little component weight as possible for this purpose. Only where many reinforcing fibers are used are these also required (targeted use of reinforcing fibers). Material, weight and costs are saved.FIG. 2 shows a detail of a textile insert 200. The insert 200 comprises a net-like base reinforcement 210 which is relatively coarse-mesh and which extends substantially through the complete side part 130 or 140 in the manner of a belt. Preferably, it is a glass fibre grid or glass fibre mesh which has, for example, a mesh width of 5 mm x 5 mm. Such net-like fabrics are available as semi-finished products or can optionally also be produced themselves (for example by belt weaving with corresponding distances between warp and weft threads). The insert 200 further comprises a local additional reinforcement formed from a plurality of individual rovings or roving threads 220, which is fastened to the base reinforcement 210 in the particularly stressed region B. The individual rovings 220 can absorb an initiated crash impulse. The rovings are formed, for example, from glass, carbon, synthetic or natural fibers. However, a fiber-homogeneous structure is preferred, in which only reinforcement fibers of one kind are used.The roving or roving threads 220 can be threaded or woven into the net structure of the base reinforcement 210 with aids 300, which are needles or weaving shuttles, for example, or optionally can also be hooked on, which is usually automated. The additional fibrous reinforcement is designed to meet the load. It is preferably provided that the rovings 220 are arranged in such a way that a planar reinforcing structure 230 is produced, as illustrated by the dotted outline. Instead of several rovings 220, only a single roving or roving thread 220 can be provided, which follows a defined curve. In an analogous manner, further additional reinforcements can be attached to the base reinforcement 210, for example at the connection points to a cross member on the vehicle body side (not shown).FIG. 3 shows another possible embodiment of the textile insert 200, in which the additional reinforcement in the region B is formed by a semi-finished fiber product blank 240, which does not show a representation according to the invention. The semi-finished fiber product blank 240 is fastened to the net-like base reinforcement 210 by means of a polymer stitching thread, for example. Individual stitching points of the stitching are denoted by the reference sign 250.In both possible embodiments shown in FIGS. 2 and 3, the net-like base reinforcement 210 can be formed with a variable mesh size, which is understood in particular to mean that the meshes in at least one additional reinforcement region B are formed smaller or narrower than in the other regions, so that a spider-net-like mesh structure results in this region B.To produce the mounting frame 100 from FIG. 1, inserts 200 prepared according to FIG. 2 and / or FIG. 3 are inserted into an injection molding tool and are encapsulated by injection molding with a short-fiber-containing plastic matrix material in a manner known per se. This manufacturing process is simple and cost-advantageous. In addition, the grid-like structures of the base reinforcements 210 can be completely injection-molded, enabling very good penetration of the inserts 200 with the short-fiber-containing plastic matrix material. Inserts 200 are completely embedded in the plastic matrix material and are no longer visible afterwards. Moreover, functional elements, such as a ribbing, for example, can be injection-molded and / or inserts serving as force introduction points can be integrated in a manner known per se.List of reference characters100 Mounting frame (component) 110 Upper frame part 120 Lower frame part 130 Side part 140 Side part 200 Insert 210 Base reinforcement 220 Roving 230 Reinforcement structure 240 Semi-finished fiber product blank 250 Stitching 300 Auxiliary B Region

Claims

Method for producing a fiber-plastic composite component (100) reinforced at least in a partial region (130, 140) by means of a textile insert (200), comprising the steps of: - manufacturing at least one textile insert (200) formed from reinforcing fibers, which textile insert comprises a net-like base reinforcement (210) and at least one local additional reinforcement (220) fastened thereto; and - placing the insert (200) in the cavity of an injection molding tool and carrying out an injection molding process by injecting a plastic matrix material into the closed cavity, wherein the insert (200) is completely embedded in the injected plastic matrix material; characterized in that the net-like base reinforcement (210) is a textile fabric formed from reinforcing fibers and having a net structure, and that at least one fiber roving (220) is used as an additional reinforcement, wherein this fiber roving (200) is threaded or woven into the net structure of the base reinforcement (210).Method according to Claim 1, characterized in that the fibre roving (220) produces a planar reinforcing structure (230).Method according to one of the preceding claims, characterized in that the net-like base reinforcement (210) has a mesh width of 3 mm to 7 mm, preferably of 4 mm to 6 mm and in particular of 5 mm.Method according to one of the preceding claims, characterized in that the plastic matrix material is a thermoplastic material enriched with short fibres.Fiber-plastic composite component (100) produced by a method according to one of the preceding claims and reinforced in at least one partial region (130, 140) with a textile insert (200) which is completely embedded in plastic matrix material and formed from reinforcing fibers, wherein the textile insert (200) has a net-like base reinforcement (210) and at least one local additional reinforcement (220) fastened thereto, wherein at least one fiber roving (220) is provided as additional reinforcement, which is threaded or woven into the net structure of the base reinforcement (210).Fiber-plastic composite component (100) according to Claim 5, characterized in that it is designed as a mounting frame for at least one heat exchanger to be arranged in the front region of a motor vehicle, the side parts (130, 140) of this mounting frame (100) being reinforced in each case with such a textile insert (200).The fiber-plastic composite component (100) according to claim 6, characterized in that the side parts (130, 140) have a wall thickness of 2 mm to 3 mm.

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