METHOD FOR PRODUCING A FIBRE COMPOSITE BODY AND FIBRE COMPOSITE BODY

Abstract

The invention relates to a method for producing a fibre composite body (2), in particular at least a part of a wheel, comprising the following steps: providing a mould (4) having at least one female mould part (6) and one male mould part, introducing a fibrous raw material (8) and a binder (10) into the female mould part (6), activating the binder (10) by an energy input (p, T) into the mould (4) to form a mould element (12) which is open to diffusion, joining together the mould element (12) which is open to diffusion and a preform structure (14), supplying a resin, so that the resin infiltrates at least partially into the mould element (12) which is open to diffusion and into the preform structure (14), and curing the resin, so that in this way the fibre composite body (2) is formed without a boundary layer.

Claims

1. A method for producing a fibre composite body (2), in particular at least a part of a wheel, comprising the following steps: providing a first mould (4) having at least one female mould part (6) and one male mould part; introducing a fibrous raw material (8) and a binder (10) into the female mould part (6); activating the binder (10) by an energy input (p, T) into the mould (4) to form a mould element (12) which is open to diffusion; joining together the mould element (12) and a preform structure (14); supplying a resin, so that the resin infiltrates at least partially into the mould element (12) which is open to diffusion and into the preform structure (14); and curing the resin, so that, as a result, the fibre composite body (2) is formed without a boundary layer.

2. The method according to claim 1, wherein the binder is added to the fibrous raw material (8).

3. The method according to claim 2, wherein the binder is thermoplastic, thermoseting or a mixture of both.

4. The method according to claim 1, wherein a polyimide material is added to the fibrous raw material (8).

5. The method according to claim 1, wherein one or more textile layers are integrated into the mould element (12) which is open to diffusion.

6. The method according to claim 1, wherein one or more textile layers are integrated when joining together the mould element (12) which is open to diffusion and the preform structure (14).

7. The method according to claim 1, wherein one or more functional elements are arranged, in particular integrated, in(to) the mould element (12) which is open to diffusion and/or in(to) the preform structure (14).

8. The method according to claim 1, wherein the mould element (12) has one or more formations for the integration of coupling load elements.

9. The method according to claim 1, wherein the energy input (p, T) takes place in multiple stages.

10. The method according to claim 1, wherein the energy input (p, T) comprises vacuum pressing or over-pressure pressing or a closing force of the at least one mould (4).

11. The method according to claim 1, wherein the at least one female mould part (6) is made of a duroplastic material or of a thermoplastic material or of a mixture of duroplastic and thermoplastic material.

12. The method according to claim 1, wherein the mould element (12) which is open to diffusion is connected to a structural segment (24), in particular in a form-fitting manner.

13. A fibre composite body (2), in particular a wheel, made of a fibre composite material having a mould element (12) which is open to diffusion and a preform structure (14), wherein the mould element (12) which is open to diffusion and the preform structure (14) are connected to one another at least partially without a boundary layer.

14. A fibre composite body (2) according to claim 13, wherein the mould element (12) which is open to diffusion and the preform structure (14) are connected to one another in a form-fitting manner.

15. A fibre composite body (2) according to claim 13, wherein the mould element (12) which is open to diffusion is formed as an insert part.

16. The fibre composite body (2) according to claim 13, wherein the mould element (12) which is open to diffusion has at least one connection to a structural segment (24), which connection is formed in particular in a form-fitting manner.

17. The fibre composite body (2) according to claim 13, wherein the mould element (12) which is open to diffusion is completely integrated into the preform structure (14), in particular is completely connected to the preform structure (14) without a boundary layer.

18. The fibre composite body (2) according to claim 13, which has a plurality of mould elements (12) which are open to diffusion.

19. The method according to claim 3, wherein: a polyimide material is added to the fibrous raw material (8); and one or more textile layers are integrated into the mould element (12) which is open to diffusion.

20. The method according to claim 19, wherein: the energy input (p, T) takes place in multiple stages; and the energy input (p, T) comprises vacuum pressing or over-pressure pressing or a closing force of the at least one mould (4).

Description

[0050] In the method shown schematically in FIG. 1 for producing a fibre composite body 2 (cf. FIG. 2), a mould 4 having a female mould part 6 and a female mould part (not shown here) is provided. In this case, the male mould part is formed to correspond to or complement the female mould part 6.

[0051] First, a fibrous raw material 8, such as carbon, glass or natural fibres, and a binder 10 are introduced into the mould 4, specifically into the female mould part 6. The binder 10 is, for example, a duroplastic or thermoplastic binder powder, or a mixture of both. After closing the mould 4, the binder 10 is activated. This takes place by means of an energy input in the form of an application of pressure p and an application of temperature T on the mould 4. The application of pressure p can be understood in this case to mean that the mould 4 and in particular the female mould part 6 and the male mould part are pressed together with a pressure in the range between 0.1 MPa and 10 MPa. In this context, the application of temperature T can be understood to mean that the mould 4 is heated to a temperature having a value between 70° C. and 180° C.

[0052] A mould element 12 which is open to diffusion is formed as a result, which mould element is then joined together with the preform structure 14 (not shown in FIG. 1). After supplying a resin which infiltrates, i.e. flows around, both the mould element which is open to diffusion and the preform structure, a second application of pressure p and an optional second application of temperature T take place. As a result, the resin is cured, so that the mould element 12 and the preform structure 14 form a fibre composite body 2.

[0053] A fibre composite body 2 of this type is shown, for example, in FIG. 2 in a perspective view. FIG. 2 shows part of a fibre composite body 2 formed as a wheel rim, which fibre composite body has a preform structure 14 and a mould element 12. The mould element 12 is formed as a spoked rim, while the preform structure 14 is formed as a rim base having spokes 18 arranged thereon.

[0054] The mould element 12 is thus formed according to FIG. 2 as a spoked rim-shaped insert part and fully meets the mechanical requirements of the structure, especially in the region of the wheel hub mount 20 and the wheel nut bushings 22. Forces usually occur in the region of the wheel hub mount 20 and the wheel nut bushings 22 for which an arrangement of a mould element 12 formed as an insert part has proven to be suitable.

[0055] In this case, the forces are transmitted between the wheel hub mount 20 and the rim base 16. Alternatively, in the embodiment according to FIG. 2, the mould element 12 formed as a spoked rim can also be enclosed by further (fabric) layers.

[0056] Also, as an alternative or in addition, further functional elements (not shown) can be arranged and in particular integrated in(to) the mould element and, for example, can form the wheel hub mount 20 and/or the wheel nut bushings 22. In this case, sleeves are usually used, which are inserted into the mould element 12.

[0057] FIG. 3 shows a sketch of a mould element 12 having structural segments 24 arranged thereon in a form-fitting manner. The arrangement of the structural segments 24 on the mould element 12 takes place in the embodiment according to FIG. 3 in the manner of a tongue-and-groove connection and thus in a form-fitting manner. However, the form fit can also be achieved by means of the infiltration of the resin into the mould element 12 which is open to diffusion, so that micro-interlocking takes place between the mould element 12 and the structural segments 24. In the embodiment, the structural segments 24 are arranged on the mould element 12 oriented radially outwards, so that the mould element 12 having the structural segments 24 arranged thereon forms at least part of a spoked rim.

[0058] The structural segments 24 can thus also be referred to as spoke connections. The form-fitting arrangement of the structural segments 24 means that, on the one hand, a simple arrangement on the mould element 12 is achieved and at the same time a sufficiently high degree of dimensional stability is ensured.

[0059] FIG. 4 is a perspective representation of a fibre composite body 2, also formed as a wheel rim. The mould element 12 having the structural segments 24 arranged thereon is arranged inside the fibre composite body 2. The mould element 12 having structural segments 24 arranged thereon is substantially the mould element 12 already shown in FIG. 3. It is easy to see here that the structural segments 24 form part of the spokes 18 and the increased dimensional stability achieved by the mould element 12 is therefore not just limited to the wheel hub mount 20 but extends into the spokes 18.

[0060] Both the mould element 12 formed as an insert part and the structural segments 24 are completely surrounded by the preform structure 14 and, in particular, are connected thereto without a boundary layer, so that complete micro-interlocking of the preform structure 14 with the mould element 12 and the structural segments 26 results by means of the infiltration. The preform structure 14 is divided into an outer cover layer 26 and an inner cover layer 28. The two cover layers 26, 28 are made of carbon and/or aramid fibres, for example.

[0061] The mould element 12 arranged here in the region of the wheel hub mount 20 is formed rotationally symmetrical in the embodiment according to FIG. 4. Alternatively, the mould element 12 can also be non-rotationally symmetrical.

[0062] FIG. 5 is a perspective representation of a fibre composite body 2 formed as a wheel rim having two mould elements 12 arranged in the rim base edge 30. Here, in each case a mould element 12 is arranged in an outer rim base edge 30a and an inner rim base edge 30b. The inner rim base edge 30b can be understood to mean the rim base edge 30 that is oriented in the direction of the wheel suspension (not shown), while the outer rim base edge 30a can be understood to mean the rim base edge 30 that is oriented away from the wheel suspension.

[0063] The two mould elements 12 are also completely enclosed by the preform structure 14 and are connected thereto in a form-fitting and material-locking manner. The two mould elements 12 also serve in this case as insert parts for mechanical stabilisation and thus increase the mechanical resilience of the rim base.

[0064] The embodiment according to FIG. 5 having the mould element 12 arranged within the rim base edge 30 can also be used in a so-called hybrid wheel. A hybrid wheel can be understood to mean a wheel rim that is made from at least two different materials. For example, a hybrid wheel can have a metal wheel centre and a rim base made of a fibre composite material.

[0065] Furthermore, variable wall thicknesses in the region of the wheel hub on the rim base edge 30 are made possible by the mould elements 12 formed as insert parts.

[0066] A cross section of a fibre composite body 2 is shown in FIG. 6. Specifically, FIG. 6 shows a cross section through a spoke 18. Connection geometries are formed as pockets in the fibre composite body 2. Load elements 32a for tension-compression stresses and load elements 32b for shear stresses are inserted into these pockets.

[0067] FIG. 7 shows part of the spoke 18 shown in FIG. 6 and its connection to a rim base 16 as an exploded representation. In this case, the load elements 32a, 32b are introduced into the rim base 16. In order to achieve a fitting arrangement of the load elements 32a, 32b in the rim base 16, said rim base has recesses 34 in the embodiment according to FIG. 7, in which recesses an upper part or upper end of the respective load elements 32a, 32b is arranged. In the embodiment according to FIG. 7, the spoke 18 is formed to be substantially rectangular. At least one load element 32a for tension-compression stresses and/or one load element 32b for shear stresses is expediently arranged on each side of the spoke 18. Alternatively, a plurality of load elements 32a, 32b can also be arranged on one side of the spoke 18 in each case.

[0068] Preferably, the upper parts of the load elements 32a, 32b lie flush in the recesses 34, so that a planar and level outer rim base edge 30a of the rim base 16 is formed. The load elements 32a, 32b arranged in this way in the rim base 16 serve to increase the mechanical resistance of the spoke 18 against tensile and compression stresses. All the spokes 18 of a fibre composite body 2 formed as a vehicle wheel preferably have load elements 32a, 32b of this type.

[0069] The free upper part or end of the respective load elements 32a, 32b is inclined or curved outwards. The corresponding recess 34 is adapted so that the load element 32a, 32b, in particular the free upper end of the corresponding load element 32a, 32b, is received flat in the recess 34.

[0070] The invention is not limited to the embodiments described above. On the contrary, other variants of the invention can also be derived from this by a person skilled in the art without departing from the subject matter of the invention. In particular, all of the individual features described in connection with the embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

LIST OF REFERENCE SIGNS

[0071] 2 Fibre composite body

[0072] 4 Mould

[0073] 6 Female mould part

[0074] 8 Fibrous raw material

[0075] 10 Binder

[0076] 12 Mould element

[0077] 14 Preform structure

[0078] 16 Rim base

[0079] 18 Spoke

[0080] 20 Wheel hub mount

[0081] 22 Wheel nut mount

[0082] 24 Structural segment

[0083] 26 Outer cover layer

[0084] 28 Inner cover layer

[0085] 30a Outer rim base edge

[0086] 30b Inner rim base edge

[0087] 32a Load element for tension-compression stress

[0088] 32b Load element for shear stress

[0089] 34 Recesses in the rim base

[0090] p Application of pressure

[0091] T Application of temperature