METHOD OF MAKING A FIBER-REINFORCED PLASTIC PART FOR WELDING TO A METAL PART

Abstract

The invention relates to a method for producing a component (1, 2) consisting of a fibre-reinforced plastic and prepared for the welding of a metal component (4), which comprises at least one fibre element (2) impregnated with a plastic matrix, wherein at least some portions of at least one metal joining partner (1) are integrated into a fibre element, a first section of the joining partner (1) being surrounded by the fibres of the fibre element (2) such that it is in contact therewith, and a second section of the joining partner (1) projecting over a surface of the fibre element (2) or lying at least in the surface, the joining partner (1) being connected, by at least some portions, to the liquid and hardening plastic matrix, especially at least by the first section. The invention also relates to a metal joining partner for integrating into a component consisting of fibre-reinforced plastic in order to weld a metal component (4) thereto.

Claims

1. A method of making a component of fiber-reinforced plastic for welding to a metal component and that has at least one fiber element embedded in a plastic matrix, the method comprising the steps of: integrating at least one metallic connector element having first and second parts into the fiber element at least in some areas with the first part of the connector element surrounded by fibers of the fiber element and the second part of the connector element projecting past a face of the fiber element or lying at least on the face and joining the connector element at least at the first part with the liquid and hardening plastic matrix.

2. The method defined in claim 1, further comprising the step, during the embedding of the at least one fiber element of: surrounding the integrated connector element completely by the plastic matrix; and subsequently exposing an area of the second part provided for the welding the plastic matrix after hardening of the latter.

3. The method defined in claim 1, wherein the connector element is a planar metal mesh, screen, or weave having openings through which extend unimpregnated fibers or into which project crossing woven wires on the sides of the connector element turned toward the fiber element between particularly unimpregnated fibers.

4. The method defined in claim 1, further comprising the steps of: surrounding the fiber element on both sides by two of the connector elements; engaging the two connector elements with each other through the thickness of the fiber element crossings of woven wires; and joining the connector elements through the fiber element by resistance welding.

5. The method defined in claim 1, wherein the connector element is formed by a planar metal plate having pin-shaped anchor elements each in turn having a head on an outer end and projecting from the face on at least one side of the component, the method further comprising the step of: integrating at least the anchor elements forming the first part of the connector element and into the fiber element by insertion of the anchor elements in the direction of thickness into the fiber element.

6. The method defined in claim 5, wherein a planar region of the connector element is integrated into the fiber element and is surrounded in a contacting manner on both sides by fibers, and the anchor elements extend in the direction of thickness from the planar part in the direction toward an outer face of the fiber element and end in or past the outer face, and the free anchor element ends form the second part.

7. The method defined in claim 5, wherein the planar part of the connector element is placed on an outer face of the fiber element and forms the second part, with the anchor elements inserted between fibers in the direction of thickness of the fiber element, and free anchor ends lying particularly within the thickness of the fiber element.

8. A metallic connector element for integration into a component of fiber-reinforced plastic for the purpose of the welding of a metal component, thereto, the connector element comprising: a planar metal plate having pin-shaped anchor elements each with an enlarged head on an outer end and projecting from the outer face on at least one side, the anchor elements forming a first part of the connector element that can be integrated into the fiber element by insertion of the anchor elements into the fiber element in the direction of thickness.

Description

[0027] FIG. 1 shows a first embodiment of the invention in which the connector element for a metal component to be welded (not shown) is formed by a lattice-like wire mesh 1 with mesh holes 1a. In the present case, a fiber element 2, for example a laid mesh or also woven fabric of reinforcing fibers (for example glass fibers, carbon fibers) is engaged on each side by a respective wire mesh 1. At the points of intersection of the wires, the wire mesh has a wire that passes over and a wire that passes under. By the placement, preferably pressing of the respective wire mesh 1 onto the fiber element 2, at least the wires that are passing over and turned toward the fiber element penetrate into the fiber element in the crossing areas, since these are the ones that project farthest toward the fiber element. The wire mesh is thus engaged by a plurality of fibers of the fiber element 2. However, to guide the fibers through the mesh holes 1a, particularly if the fiber element 2 is a laid fleece, in which case the fibers can be woven with the wire mesh through its mesh openings.

[0028] Here, the wire meshes 1 can contact each other through the fiber element at the wires that pass over and facing one another, for example. The possibility thus exists of interconnecting the wire meshes, for example with resistance welding. The fibers themselves can also bond to the wires, for example by integration (for example solid-state welding) or by fusing of the fibers or of a coating surrounding them in order to achieve adhesion, and/or the fibers are clamped between the wires by a frictional connection. The wire meshes 1 thus already form an integral part that can no longer be separated from the fibers, so that forces exerted on the wire meshes 1 are transmitted to the fibers.

[0029] After the joining of the wire meshes 1 to one another and preferably to the fibers of the fiber element 2 as well, the embedding with the plastic matrix, for example epoxy resin, can be performed, which also bonds to the wire meshes. After that, they form an integral part of the finished fiber-reinforced plastic component and can act as connector elements to which a metal component can be welded, preferably via welding projections, since the wires of the wire mesh 1 that pass over and project away from the fiber element 2 can be utilized as welding points. In terms of the general description of the invention, the wires that pass over and point toward the fiber element thus form the first part of the connector element integrated into the component, and the wires that pass over and face toward the later metal component form the second part, to which the metal component can be welded.

[0030] FIG. 2 shows an alternative embodiment where the connector element is a metal plate 1 that has a plurality of pin-shaped anchor elements 3 on its face turned toward the fiber element 2. These anchor elements 3 have a length that is less than a thickness D of the fiber element 2 and have larger-diameter heads 3a that do not extend completely through the fiber element 2 in the direction of thickness, i.e. they are partially embedded in the fiber element 2. The metal plate 1 is secured to the fiber element 2 at these heads alone. The metal plate 1 can be inserted into the fiber element before or also after embedding with but before hardening of the matrix material, particularly such that its outer face 1b, which is the upper outer face here, lies above the outer face 2b of the fiber element and is not covered by the matrix material. This face 1b can thus be used as a welding island in the composite component in order to join a metal component 4 therewith, for example by one-sided resistance (projection) welding, laser beam welding, or other welding methods. When resistance projection welding is used, natural, pronounced, or massive projections can be considered for use as welding projections.

[0031] FIG. 3 and FIG. 4 show an additional embodiment where the connector element is a metal plate 1 that has pin-shaped anchor elements 3 with heads 3a on both sides. In this embodiment, both the metal plate 1 and the pin regions of the anchor elements 3 and, in part, the heads 3a thereof are to be regarded as the first part, that comes to be an integral part of the component. Here, the plate 1 is preferably arranged centrally in a fiber element 2 that can be formed for example by two fiber weaves that have been pressed over the anchor elements 3 on both sides of the plate.

[0032] The anchor elements 3 have a length that is such that the heads thereof project at least partially out of the face of the fiber element. The connector element can in turn be integrated into the component by embedding with matrix material. The bilateral projecting heads can act as projections for resistance welding.

[0033] After this, a metal component 4 can be welded at any time without any difficulty, for example using resistance projections, to the outwardly facing spherical heads, particularly on both sides.

[0034] FIG. 5 shows a connector element in the form of a plate 1 in which the shape of each anchor element 3 along with its head 3 is made by punching or cutting, for example laser cutting. By bending the contoured anchor elements 3 about an axis A that lies on the plane, the anchor elements can be embodied so as to project from the plate outer face, thus enabling the plate 1 to be inserted therewith into a fiber element.