Method for connecting components which have a fibre-reinforced thermoplastic plastic

Abstract

A method for connecting components having a fibre-reinforced thermoplastic plastic includes provision of a first component with a first joining surface, provision of a second component with a second joining surface, flush placement of the first joining surface against the second joining surface in order to form a connection joint, placement of a friction stir welding tool against the connection joint, or a surface directly adjacent thereto, of at least one of the components, softening of the first component and the second component, in each case in a region adjacent to the connection joint, by rotation of the tool, such that the thermoplastic plastic of the two components locally fuses, and movement of the tool along the connection joint for the purposes of connecting the two components by formation of a fusion seam, wherein portions of reinforcement fibres are stirred in to increase the strength of the fusion seam.

Claims

1. A method for connecting components which have a fibre-reinforced thermoplastic plastic, the method comprising: providing a first component with a first joining surface; providing a second component with a second joining surface; flush placement of the first joining surface against the second joining surface in order to form a connection joint; placing a friction stir welding tool against the connection joint, or a surface directly adjacent thereto, of at least one of the components; softening the first component and the second component, in each case in a region adjacent to the connection joint, by rotation of the tool, such that the thermoplastic plastic of the two components locally fuses; and moving the tool along the connection joint for the purposes of connecting the two components by formation of a fusion seam, wherein portions of reinforcement fibres are stirred into the fusion seam in order to increase the strength of the fusion seam wherein the first and second components comprise reinforcement fibres, and portions of the reinforcement fibres are separated from the respectively adjacent regions of the components, and stirred into the fusion seam, as a result of the rotation of the tool, wherein the tool has a frustoconical tip with a lateral surface on which radial projections, channels or indentations are arranged, and wherein the tool cuts the reinforcement fibres.

2. The method according to claim 1, wherein, during the movement along the connection joint, the tool is pressed on in order to generate a targeted surface friction.

3. The method according to claim 1, wherein the connection joint is a butt joint, wherein the first joining surface and the second joining surface are in each case end surfaces and lie against one another in butting fashion, and wherein the tool is moved along the connection joint transversely with respect to the first and second components and an axis of rotation of the tool runs parallel to the joining surfaces.

4. The method according to claim 1, wherein the connection joint is a corner, T or oblique joint, and the first and second components form an inside edge, and wherein the tool is placed against the inside edge and an axis of rotation of the tool encloses a substantially equal angle with both components.

5. The method according to claim 1, wherein the connection joint is an overlap joint, and wherein the tool is placed onto one of the first and second components and is oriented transversely with respect to the joining surface, wherein the tool generates a fusion seam extending from one of the first and second components directly adjacent to the tool into the adjacent other of the first and second components.

6. The method according to claim 5, wherein two or more mutually spaced-apart fusion seams are generated on the same joining surface.

7. The method according to claim 1, wherein the connection joint is formed along a closed contour.

8. The method according to claim 1, wherein the thermoplastic plastic is selected from a group of plastics, the group consisting of: polypropylene styrene (PPS); polyether ether ketone (PEEK); polyether ketone ketone (PEKK); polyetherimide (PEI); and polyaryl ether ketone (PAEK).

9. The method according to claim 1, wherein the reinforcement fibres are carbon fibres or glass fibres.

10. The method according to claim 1, wherein, in addition to the portions of reinforcement fibres, an additive is mixed in in order to improve the strength of the fusion seam.

11. The method according to claim 1, wherein the first and second components are in the form of fuselage or structural components of an aircraft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features, advantages and possible uses of the present invention will emerge from the following description of the exemplary embodiments and from the figures. Here, all of the features described and/or illustrated in the figures form the subject matter of the invention individually and in any desired combination, even independently of the combination of said features in the individual claims or the back-references thereof. Furthermore, in the figures, the same reference signs are used for identical or similar objects.

(2) FIGS. 1 to 3 show two components which form a butt joint and which are connected to one another.

(3) FIGS. 4a to 4i show further connection joints.

(4) FIG. 5 shows a schematic block-based illustration of a method for connecting two components.

DETAILED DESCRIPTION

(5) FIG. 1 shows, in highly schematic form, a first component 2 with a first joining surface 4, reinforcement fibres 6 contained therein, and a matrix material 8, surrounding the reinforcement fibres 6, in the form of a thermoplastic plastic. The first component 2 may extend over a considerably larger area, and be of a different construction, than illustrated here. The present illustration is intended merely to illustrate the individual method steps. FIG. 1 furthermore shows a second component 10 with a second joining surface 12, reinforcement fibres 6, and a matrix material 8 in which the reinforcement fibres 6 are embedded.

(6) By way of example, the matrix material of the two components 2 and 10 is polypropylene styrene (PPS), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyetherimide (PEI), polyaryl ether ketone (PAEK), or some other thermoplastic material. It may be expedient for the reinforcement fibres 6 to be realized for example as carbon fibres, though glass fibres could also be expedient for components for which lower loads are to be expected.

(7) For the connection of the two components 2 and 10, the two joining surfaces 4 and 12 are placed against one another. The joining surfaces then butt against one another in a flush manner, such that no gap is situated in between. This yields a connection joint 14, which in this case is a butt joint.

(8) For the connection of the two joining surfaces 4 and 12, a tool 16 is placed on and is moved along the connection joint 14. This yields the fusion seam 18 shown in FIG. 3. Said fusion seam extends all the way through both components 2 and 10, wherein, as a result of action of the tool 16, matrix material from adjacent regions 20 and 22 of the two components 2 and 10 is fused and stirred. This leads to a materially bonded connection with high load-bearing capacity.

(9) As is illustrated in highly schematic form in FIG. 2, the tool 16 is a friction stir welding tool, which is formed with radial projections 24 or channels and/or indentations on a circumferential surface and which thereby leads to stirring of the softened material. The projections 24 furthermore have the effect that, in the adjacent regions 20 and 22, portions of the reinforcement fibres 6 are cut off and stirred into the fusion seam 18 by the tool 16. This consequently leads to reinforcement of the fusion seam 18 by means of short fibres, which further increases the strength.

(10) As illustrated in FIGS. 4a to 4e, it is self-evidently also possible for other forms of seam and connection joints to be taken into consideration. For example, FIG. 4a shows a connection joint 30 in the case of which the first component 2 and the second component 10 enclose a right angle. A fusion seam 26 is arranged at an inside edge 28 and could be realized for example by means of the rotating tool 16 if the axis of rotation thereof encloses the same angle with both components 2 and 10, that is to say forms an angular bisector. The connection joint 30 is known for example as a corner joint.

(11) FIG. 4b shows a connection joint 32 in the case of which the first component 2 forms a much larger first joining surface 34 than in the other examples. The second component 10 has a second joining surface 36 which corresponds to said first joining surface and which is placed against the first joining surface 34. The two components 2 and 10 overlap, and the connection joint 32 is therefore an overlap joint. A fusion seam 38 extends from an outer, first component surface 40 in the direction of the connection joint 32 and partially also extends into the second component 10.

(12) FIG. 4c likewise shows the overlap joint 32, wherein two fusion seams 38 are however provided in order to realize a higher tensile strength.

(13) FIG. 4d shows an arrangement of a first component 2, a second component 10 and a web 40 as further component. Here, two overlap joints 32 are formed. A fusion seam 38 extends through each of the overlap joints 32.

(14) FIG. 4e shows a further variant, which is a combination of the illustration in FIG. 4d and FIG. 3. Here, it is consequently the case that two fusion seams 38 and one fusion seam 18 is arranged at one butt joint 14.

(15) FIG. 4f shows a connection joint 31 at an L-shaped first component 2 and a flat second component 10. The fusion seam 26 corresponds to that from FIG. 4a.

(16) FIG. 4g shows a connection joint 30 similar to that in FIG. 4a, wherein, however, additional material has been applied and fused at the inside edges 28, such that no cutting-off of fibres has taken place.

(17) FIG. 4h is a modification of FIG. 4a, wherein two inside edges 28 are provided with a fusion seam 26.

(18) FIG. 4i shows a fusion seam 41 formed along a closed contour 39. The first component 2 may for example lie flat on the second component 10 and be welded in a flat manner to the second component 10 by movement of the tool 16 along the contour 39.

(19) FIG. 5 shows, for the sake of completeness, a schematic block-based illustration of a method 42 according to an aspect of the invention, having the steps of provision 44 of a first component with a first joining surface, of provision 46 of a second component with a joining surface, of flush placement 48 of the first joining surface against the second joining surface in order to form a connection joint, of placement 50 of a friction stir welding tool against the connection joint, or a surface directly adjacent thereto, of at least one of the components, of softening 52 of the first component and of the second component, in each case in a region adjacent to the connection joint, by rotation of the tool, such that the thermoplastic plastic of the two components locally fuses, and of movement 54 of the tool along the connection joint for the purposes of connecting the two components by formation of a fusion seam. As a result of the rotation of the tool, portions of reinforcement fibres are cut off 56 from the respectively adjacent regions and are stirred into 58 the fusion seam in order to increase the strength of the fusion seam.

(20) It is additionally pointed out that “having” or “comprising” does not rule out other elements or steps, and “a” or “an” does not rule out a multiplicity. It is also pointed out that features that have been described with reference to one of the above exemplary embodiments may also be used in combination with other features of other exemplary embodiments described above. Reference signs in the claims are not to be regarded as limiting.

(21) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

REFERENCE SIGNS

(22) 2 First component

(23) 4 First joining surface

(24) 6 Reinforcement fibre

(25) 8 Matrix material

(26) 10 Second component

(27) 12 Second joining surface

(28) 14 Connection joint

(29) 16 Tool

(30) 18 Fusion seam

(31) 20 Adjacent region

(32) 22 Adjacent region

(33) 24 Projection

(34) 26 Fusion seam

(35) 28 Inside edge

(36) 30 Connection joint

(37) 31 Connection joint

(38) 32 Connection joint, overlap joint

(39) 34 First joining surface

(40) 36 Second joining surface

(41) 38 Fusion seam

(42) 39 Contour

(43) 40 Component surface

(44) 41 Fusion seam

(45) 42 Method

(46) 44 Provision of first component

(47) 46 Provision of second component

(48) 48 Flush placement

(49) 50 Placement of the tool

(50) 52 Softening

(51) 54 Movement

(52) 56 Separation

(53) 58 Stirring-in