DE102013212694A1 - Method and shaping tool for producing a fiber composite hollow component - Google Patents

Abstract

The present invention relates to a method and a shaping tool for producing a hollow fiber composite component. The method comprises the steps of: a) providing an inflatable support structure (2); b) applying fiber material (4) to the carrier structure (2) to produce a preform (1); c) introducing the preform (1) on the carrier structure (2) into a shaping tool (6); d) generating an overpressure (P) within the carrier structure (2) such that the preform (1) is pressed through the carrier structure (2) on shaping surfaces (7a, 8a) of the shaping tool (6). According to the invention, the support structure (2) has a corrugated hose (3) or a corrugated hose-like element, at least in sections. The shaping tool has a fiber material (4) applied to an inflatable support structure (2), the shaping tool (6) for receiving the preform (1) on the support structure (2) and introducing excess pressure (P) into the interior of the support structure (2 ) in such a way that the fiber material (4) of the preform (1) is pressed, formed and furnished on the shaping surfaces (7a, 8a) of the shaping tool (6) under the effect of the excess pressure (P) by the carrier structure (2). According to the invention, the shaping tool (6) has a pressure connection part (9) with a pressure connection (11) for introducing the excess pressure (P), the pressure connection part (9) has a receiving structure (9c) pointing towards an interior (6a) of the shaping tool (6) ) for receiving an axial end (5) of the support structure (2), and a pressure connection line (9a) is provided, which connects the interior (6a) with the pressure connection (11) and in a surface (9c) enclosed by the receiving structure (9c) 9b) ends.

Description

The present invention relates to a method and a shaping tool for producing a fiber composite hollow component.

It is known to produce CFRP hollow components through the use of contoured three-dimensional support cores (eg, sand cores, wax cores, etc.) or inflatable tubes, tube bladders, and inflatable blow mold components. In this case, a preform is first produced by fiber material is applied to a provided support structure. The preform on the support structure is then introduced into a forming tool, and by use of the illustrated aids, the reinforcing fibers used during the process are pressed and shaped on forming surfaces of the forming tool. Depending on the type of process, the reinforcing fibers are already provided in advance with a matrix system. Alternatively, the matrix is injected into the closed forming tool (RTM method). When using support cores based on inflatable elements while the tightness of the support cores is ensured by appropriate measures. After hardening of the reinforcing matrix, the end component can then be removed from the shaping tool.

Contoured support cores with a usually three-dimensional geometry can essentially only be occupied by discontinuous processes with reinforcing fibers. For example, fiber preforms may be either placed on the cores or placed directly into the later forming tool. Alternatively, the contoured three-dimensional support cores can also be provided with reinforcing fibers by means of a braiding technology. This is initially also a discontinuous production process. An automation of the manufacturing process is possible in a first approach, for example, that several cores are positioned and braided together in a circular path.

An object of the present invention is to provide a method and a forming tool which avoids the disadvantages of the prior art. In particular, it is an object of the present invention to provide a method and a forming tool for making a fiber composite hollow member using an inflatable. To provide carrier structure, which in terms of at least one of the aspects of process safety, automation, flexibility in the dimensioning of the fiber composite hollow component, handling and contouring of the preform or the hollow component, the design effort, cleaning effort and tooling costs to improve. The above object is achieved at least in some aspects by a method according to the invention with the features of claim 1 and by a forming tool having the features of claim 10. Here are features and details that are described in connection with the inventive method, also in connection with the shaping tool according to the invention and in each case vice versa and alternately, so that with respect to the disclosure of the individual aspects of the invention is always mutually referenced or can be.

• a) Bereitstellen einer aufblasbaren Trägerstruktur;
• b) Aufbringen von Fasermaterial auf die Trägerstruktur, um einen Vorformling herzustellen;
• c) Einbringen des Vorformlings auf der Trägerstruktur in ein Formgebungswerkzeug;
• d) Erzeugen eines Überdrucks innerhalb der Trägerstruktur derart, dass der Vorformling durch die Trägerstruktur an Formgebungsflächen des Formgebungswerkzeugs gedrückt wird,

vorgeschlagen. Erfindungsgemäß weist die Trägerstruktur wenigstens abschnittweise einen Wellschlauch oder ein wellschlauchartiges Element auf. Das Verfahren kann insbesondere für die Herstellung eines Faserverbund-Hohlbauteils für den Fahrzeugbau, vorzugsweise den Automobilbau oder den Motorradbau, angepasst sein. Unter einem Wellschlauch wird im Sinne der Erfindung eine schlauchartige Struktur, insbesondere aus einem Kunststoff (Thermoplast, PVC, etc.) verstanden, die eine im wertesten Sinne wellenartige bzw. gewellte Außenwand aufweist; insbesondere sind auch handelsübliche Wellschläuche zur Verwendung in dem erfindungsgemäßen Verfahren geeignet. Die Wellenform der Außenwand kann gewendelt oder ringförmig sein, und ermöglicht eine axiale Streckbarkeit der Trägerstruktur wenigstens in dem jeweiligen Abschnitt oder insgesamt, ohne dass der Außenradius des Wellschlauchs wesentlich verändert wird. Dadurch bleibt der Vorformling auf der Trägerstruktur (dem Wellschlauch) formstabil, auch wenn eine Streckung des Wellschlauchs erfolgt. Die Wellenstruktur stellt auch eine gewisse Versteifung und Tragfähigkeit trotz vergleichsweise geringer Wandstärke bereit. Daher ist die Trägerstruktur auch drucklos weitgehend formstabil. Dennoch ist der Wellschlauch so flexibel, dass bei ausreichendem, technisch sinnvollem Innendruck eine für die Zwecke des Blasformens hinreichende Expansion erreicht und der Innendruck an das Fasermaterial weitergegeben werden kann. Zusätzlich haben die Erfinder festgestellt, dass eine Konturausbildung des Vorformlings aufgrund der axialen Dehnbarkeit bei radialer Formstabilität des Wellschlauchs gegenüber herkömmlichen aufblasbaren Stützkernen verbessert ist, da unter anderem bei einseitiger Streckung des Wellschlauchs auch eine Krümmung des Vorformlings und damit des herzustellenden Hohlbauteils möglich ist. Das Aufbringen des Fasermaterials auf die Trägerstruktur kann beispielsweise, aber nicht nur, das Flechten von Langfasern, Auflegen oder Wickeln von Fasermatten und andere bekannte Techniken umfassen. Das Einbringen des Vorformlings in das Formgebungswerkzeug erfolgt vorzugsweise so, dass das Fasermaterial des Vorformlings zwischen der Trägerstruktur und Formgebungsflächen des Formgebungswerkzeugs liegt. Nach der Erzeugung des Überdrucks und dem damit verbundenen Andrücken des Vorformlings an die Formgebungsflächen des Formgebungswerkzeugs schließen sich weitere, an sich bekannte Verfahrensschritte an, wie etwa ein Aushärten des Vorformlings in der Form, ein Ablassen des Drucks, ein Öffnen der Form, ein Herausnehmen des Bauteils aus der Form und ein Entfernen der Trägerstruktur.According to a first aspect of the present invention, a method for producing a fiber composite hollow component comprising the steps:

• a) providing an inflatable support structure;
• b) applying fiber material to the support structure to produce a preform;
• c) introducing the preform on the support structure into a forming tool;
• d) generating an overpressure within the support structure such that the preform is pressed by the support structure on shaping surfaces of the forming tool,

proposed. According to the invention, the support structure at least in sections a corrugated hose or a corrugated hose-like element. The method can be adapted in particular for the production of a fiber composite hollow component for vehicle construction, preferably automobile construction or motorcycle construction. For the purposes of the invention, a corrugated tube is understood to be a tubular structure, in particular made of a plastic (thermoplastic, PVC, etc.), which has a wave-like or corrugated outer wall in the best sense possible; In particular, commercially available corrugated hoses are also suitable for use in the method according to the invention. The outer wall wave form may be coiled or annular, and allows for axial extensibility of the support structure at least in the respective portion or in total, without significantly changing the outer radius of the corrugated tube. As a result, the preform on the support structure (the corrugated hose) remains dimensionally stable, even if an extension of the corrugated hose takes place. The wave structure also provides a degree of stiffening and bearing capacity despite comparatively low wall thickness. Therefore, the support structure is also largely free of pressure, without pressure. Nevertheless, the corrugated tube is so flexible that sufficient, technically meaningful internal pressure reaches a sufficient for the purposes of blow-molding expansion and passed the internal pressure to the fiber material can be. In addition, the inventors have found that a contour formation of the preform is improved due to the axial extensibility with radial dimensional stability of the corrugated hose compared to conventional inflatable support cores, as among other things in one-sided extension of the corrugated hose and a curvature of the preform and thus the hollow component to be produced is possible. The application of the fibrous material to the support structure may include, for example, but not limited to, the braiding of long fibers, laying or winding of fiber mats, and other known techniques. The introduction of the preform in the forming tool is preferably carried out so that the fiber material of the preform is located between the support structure and shaping surfaces of the forming tool. After the generation of the overpressure and the associated pressing of the preform to the forming surfaces of the forming tool, further, known per se procedures follow, such as hardening of the preform in the mold, releasing the pressure, opening the mold, removing the mold Component from the mold and removing the support structure.

In a preferred embodiment of the method of this aspect of the invention, the support structure is held during execution of the step of applying fibrous material to the support structure such that an axial change in length of the support structure is prevented. The holding of the support structure may be realized, for example, but not limited to, by an appropriate pulling unit (which is used, for example, for a method step of stretching the support structure to be described later) or the like. This enables a stable application of the fiber material on the support structure.

In a preferred development of the method of this aspect of the invention, after the application of fiber material to the carrier structure, the carrier structure with the applied fiber material is cut to a length that at least substantially corresponds to a length of the fiber composite hollow component to be produced. This means that the support structure (the corrugated hose) can be braided with excess length to be subsequently shortened to component length. On the one hand, this can facilitate the process of applying the fiber material, such as a braiding process, on the other hand, it can improve the unit of preform with carrier structure to be introduced into the forming tool in terms of handling, space, weight, etc. In other words, it can be formed on a single corrugated tube, the preforms of several components in a single operation, which are then cut to the appropriate length. Thus, an automation of the process can be improved, and it is also a continuous meshing and lengthening possible. Alternatively, it is of course also possible to apply fiber material on a portion of the corrugated tube corresponding to an individual length of a preform, for instance between stops, in order to produce only a single preform in each case.

In a particularly preferred embodiment of the method of this aspect of the invention, after the application of the fiber material and before the introduction of the preform into the forming tool, the carrier structure is stretched in such a way that a fiber material-free end of the carrier structure is produced. In other words, the support structure is "pulled out" under the preform so that at least one free end projects beyond an axial length of the preform, but still the preform remains supported over the entire length. This free end of the support structure can be clamped for inflation in the forming tool, wherein the fiber material can remain free.

This makes it possible to carry out the blow molding so that the fiber material undergoes no excessive stresses. This can also contribute to the quality of the fiber composite hollow component.

In other words, the method of this aspect of the invention may be configured such that the overpressure is introduced into the interior of the carrier structure via an end of the carrier structure that is free of fiber material. Therefore, in the forming tool no movable sliding element for initiating the pressing force is required. The cleaning effort of the tool and the total tool costs can be reduced. In addition, process reliability is further increased.

In preferred embodiments, the method can be configured in such a way that the fiber material applied to the carrier structure is provided with a matrix material (for example impregnated or impregnated) prior to application to the carrier structure. Equally, it is possible to provide the preform with a matrix material as a whole before it is introduced into the forming tool (for example, to impregnate it). Finally, it is also possible to inject a matrix material with already inserted preform on the forming tool. In this way, a fiber-matrix composite is produced, which can harden in the forming tool to form a fiber composite hollow component.

According to a further aspect of the present invention is a forming tool for producing a fiber composite hollow component from a preform, which on a The shaping tool is designed and arranged for receiving the preform on the support structure and introducing overpressure into the interior of the support structure in such a way that the fiber material of the preform is pressed against shaping surfaces of the shaping tool under the effect of the overpressure by the support structure becomes. According to the invention, the shaping tool has a pressure connection part with a pressure connection for introducing the overpressure, the pressure connection part having a receiving structure pointing towards an interior of the forming tool, in particular an annular groove designed to receive an axial end of the support structure, sealing means for pressure-tight sealing of the Receiving structure may be preferably provided with the axial end of the support structure accommodated therein and wherein a pressure connection line is provided which connects the interior of the forming tool to the pressure supply port and terminates in a surface of the pressure connection part enclosed by the receiving structure.

The proposed shaping tool of this aspect of the invention is particularly suitable and designed for processing a preform made of a fiber material, which is applied to a carrier structure, which has at least a sectionally a corrugated hose or a corrugated hose-like element. In particular, it is possible or is made possible by the specially adapted design and training, one end of the support structure, which was generated by axial stretching of the corrugated hose or corrugated hose portion and is free of fiber material to receive in the receiving structure. The forming tool of this aspect of the invention is thus adapted for use in the above-described methods and therefore can realize the same advantages as well. Further features, objects and effects of the invention will become apparent from the description and the accompanying drawings.

In the drawings:

1 a schematic representation of a preform on a support structure for illustrating a method step as an embodiment of the present invention;

2 a schematic representation accordingly 1 with an axially elongated support structure for illustrating a further method step of this embodiment;

3 a schematic representation of the preform with the support structure of 2 in a forming tool for illustrating a still further process step of this embodiment, wherein the forming tool itself is another embodiment of the present invention.

Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings. The same component in several figures are each provided with the same reference numerals. Components and features, purposes, and effects described in reference to an exemplary embodiment are, unless expressly or implicitly excluded, to be deemed to be applicable in any other embodiment and are also to be deemed disclosed in relation to the other embodiment, even if they: not explicitly shown and / or described there. It is also to be understood that the drawings are to be understood as schematic and that no restrictions with regard to specific dimensions or size relationships should be taken from them, unless this is expressly so described.

Based on 1 to 3 Hereinafter, a method for producing a fiber composite hollow member as an embodiment of the present invention and a forming tool as another embodiment of the present invention will be described.

As shown in 1 becomes a fiber material 4 on a provided support structure 2 , which in this embodiment, a corrugated hose 3 is, braided to a preform 1 manufacture. The corrugated tube 3 has a longitudinal axis L. Without limitation of generality, the corrugated hose 3 a helical rotating shaft 3a on.

Thus presents 1 a method step of providing the support structure 2 and applying the fiber material 4 on the support structure 2 represents.

2 shows in a schematic representation accordingly 1 a state in which the corrugated tube 3 (the carrier structure 2 ) was stretched by tension (arrow "Z") by a predetermined amount. By stretching the corrugated hose 3 has a free end 5 formed, which of the preform 1 (the fiber material 4 ) protrudes in the axial direction.

Thus shows 2 a process step of stretching the support structure 2 such that one of fiber material 4 free end 5 the support structure 2 is produced.

3 shows a schematic representation of the preform 1 on the support structure 2 which is in a forming tool 6 is introduced.

The forming tool 6 , which is also another embodiment of the present invention, has a top 7 as a first part form and a lower part 8th as a second partial form. The top 7 and the lower part 8th each have cylinder half-shell-shaped sections, which forming surfaces 7a . 8a form. The shaping surfaces 7a . 8a thus limit an interior 6a of the forming tool 6 in the radial direction. The shaping surface 7a of the top 7 and the shaping surface 8a of the lower part 8th are in shape and size to the outer contour of the preform 1 customized.

The lower part 8th of the forming tool 6 has a pressure connection part 9 on top of the interior 6a of the forming tool 6 limited in the axial direction. The top 7 and the lower part 8th with its pressure connection part 9 are adapted to each other in shape to the closed interior 6a to enclose. At a not shown other axial end of the forming tool 6 can one or both of the shell 7 and the lower part 8th have a closure part, the interior 6a of the forming tool 6 bounded on that side in the axial direction. Alternatively, a lid (not shown in detail) may be provided for this purpose.

The pressure connection part 9 has a pressure connection line 9a on that the interior 6a of the forming tool 6 connects with an environment and in one the interior 6a in the axial direction limiting surface 9b of the pressure connection part 9 to the interior 6a opens. In the area 9b is also a receiving structure 9c formed, which is formed in this embodiment as an annular groove. The recording structure 9c is to receive the free end 5 of the corrugated tube 3 (the carrier structure 2 ) customized. A sealant 10 which is an O-ring in the present embodiment is in the receiving structure 9c used to the free end 5 of the corrugated tube 3 elastically absorb and so an inside of the support structure 2 from the rest of the interior 6a of the forming tool 6 seal (ie, gas-tight to complete).

At an outer end of the pressure connection line 9a is a pressure connection 11 provided, which is connected to a compressed air source.

Thus presents 3 a method step of introducing the preform 1 standing on the support structure 2 is arranged in the forming tool 6 In this case, an arrow "P" symbolizes a further method step of generating an overpressure within the support structure 2 such that the preform 1 through the support structure 2 to the shaping surfaces 7a . 8a of the forming tool 6 is pressed.

In not further illustrated, further process steps of the preform 1 within the forming tool 6 allowed to cure. It should be understood that the fiber material 4 of the preform 1 with a matrix material (not shown in detail) is soaked. In this case, the matrix material via channels not shown in the sub-forms 7 . 8th of the forming tool 6 be injected in the manner of the known RTM method. Alternatively, the matrix material may be applied to the support structure in an intermediate step 2 applied fiber material 4 can be applied or in a preparatory step, which is still before the in 1 the process steps to be performed, the fiber material 4 be provided with the matrix material.

The invention has been described above with reference to preferred embodiments, variants, alternatives and modifications and illustrated in the figures. These descriptions and illustrations are purely schematic and do not limit the scope of the claims, but are merely illustrative of them. It is understood that the invention can be embodied and modified in many ways without departing from the scope of the claims.

For example, the illustration in FIG 1 be understood that the fiber material 4 on the the support structure 2 forming corrugated pipe 3 is applied with a length corresponding to a component length. However, it is equally conceivable and preferred, the fiber material 4 on a corrugated pipe 3 any length to apply and then cut the arrangement to a desired length. This can also be done in a continuous process, for example, fiber material 4 continuously on a quasi endless corrugated hose 3 is braided and of the braided corrugated pipe 3 each pieces of desired length are cut off.

It is further preferred that the corrugated tube 3 is held axially during the Beflechendes or occupancy with the fiber material so that the corrugated tube 3 does not lengthen in this process step.

Although in the figures, the support structure 2 as completely out of the corrugated pipe 3 is shown, it is also readily conceivable that only one end portion has a corrugated tube-like structure. This end section can then analogously to the representation in 2 be pulled out in the direction of Z and a free end 5 form. A central portion, which does not necessarily have to be in the form of a corrugated tube, can also have any three-dimensional shape and does not have to be continuously cylindrical, as shown in the figures.

In the figures, the corrugated tube 3 represented with a wave-shaped pointed wave. It should be understood that this illustration is purely schematic and does not limit the inventive concept in any way. The profile of the wave 3a may also be rounded and may particularly preferably be designed so that in the compressed state of the corrugated pipe 3 a flat or nearly flat outer surface results while the shaft 3a extends bulging or bellows-like inward or bulges. Also, the wave can 3 , Instead of a continuous helix, a plurality of individual annular waves in the outer surface of the corrugated tube or in a portion of the support structure 2 are formed.

While in 3 only one axial end of the arrangement according to the invention is shown, it is to be understood that at the other, in the figure not shown axial end of the corrugated hose 3 by suitable means such as a plug, a weld, a lid or the like or corresponding shape features of the forming tool 6 can also be completed gas-tight.

As far as in the figures, a radial gap between the fiber material 4 and the support structure 2 is shown, this serves primarily the illustration and clarity of representation. In practice, the support structure 2 tight with the fiber material 4 to be occupied.

It is understood that the skilled person can make various modifications, variations and developments on the basis of the drawings illustrated and described above, without departing from the scope of the invention defined by the appended claims.

LIST OF REFERENCE NUMBERS

1

preform

2

support structure

3

corrugated hose

3a

wave

4

fiber material

5

free end

6

shaping tool

6a

inner space

7

Upper part (part form)

7a

shaping surface

8th

Lower part (part form)

8a

shaping surface

9

Pressure connector

9a

Pressure connection line (bore)

9b

area

9c

Receiving structure (annular groove)

10

sealant

11

pressure connection

L

longitudinal axis

P

overprint

Z

tensile direction

The above list of reference numbers and abbreviations is an integral part of the description.

Claims (10)

Method for producing a fiber composite hollow component, in particular for vehicle construction, comprising the steps of: a) providing an inflatable support structure ( 2 ); b) application of fiber material ( 4 ) on the support structure ( 2 ) to a preform ( 1 ) to produce; c) introduction of the preform ( 1 ) on the support structure ( 2 ) into a forming tool ( 6 ); d) generating an overpressure (P) within the support structure ( 2 ) such that the preform ( 1 ) through the support structure ( 2 ) at forming surfaces ( 7a . 8a ) of the forming tool ( 6 ) is pressed; characterized in that the support structure ( 2 ) at least in sections a corrugated hose ( 3 ) or a corrugated-like element. A method according to claim 1, characterized in that during the execution of step b) the support structure ( 2 ) is held so that an axial change in length of the support structure ( 2 ) is prevented. Method according to claim 1 or 2, further characterized by the step: b-1) cutting the support structure ( 2 ) with the applied fiber material ( 4 ) after step b) and before step c) to a length which at least substantially corresponds to a length of the fiber composite hollow component to be produced. Method according to one of the preceding claims, further characterized by the step: b-2) stretching of the support structure ( 2 ) after step b) and before step c) before introduction into the forming tool ( 6 ) such that one of Fiber material ( 4 ) free end ( 5 ) of the support structure ( 2 ) is produced. Method according to one of the preceding claims, characterized in that in step c) a fiber material-free end ( 5 ) of the support structure ( 2 ) in a pressure connection part ( 9 ) of the forming tool ( 6 ) is taken pressure-tight. Method according to one of the preceding claims, characterized in that the overpressure (P) via a fiber material ( 4 ) free end ( 5 ) of the support structure ( 2 ) in the interior of the support structure ( 2 ) is initiated. Method according to one of the preceding claims, characterized in that on the support structure ( 2 ) applied fiber material ( 4 ) is provided with a matrix material before step b). Method according to one of the preceding claims, characterized in that the preform is provided with a matrix material before step c). Method according to one of the preceding claims, characterized in that a matrix material via the forming tool ( 6 ) is injected. Shaping tool ( 6 ) for producing a fiber composite hollow component from a preform ( 1 ) mounted on an inflatable support structure ( 2 ) applied fiber material ( 4 ), wherein the forming tool ( 6 ) for receiving the preform ( 1 ) on the support structure ( 2 ) and introducing overpressure (P) into the interior of the support structure ( 2 ) such that the fiber material ( 4 ) of the preform ( 1 ) under the effect of the overpressure (P) by the carrier structure ( 2 ) at forming surfaces ( 7a . 8a ) of the forming tool ( 6 ), is formed and arranged, characterized in that the forming tool ( 6 ) a pressure connection part ( 9 ) with a pressure connection ( 11 ) for introducing the overpressure (P), wherein the pressure connection part ( 9 ) one to an interior ( 6a ) of the forming tool ( 6 ) recording structure ( 9c ), in particular annular groove, which for receiving an axial end ( 5 ) of the support structure ( 2 ) is formed, wherein preferably sealing means ( 10 ) for pressure-tight sealing of the receiving structure ( 9a ) with the axial end received therein ( 5 ) of the support structure ( 2 ) are provided, and wherein a pressure connection line ( 9a ) is provided, which the interior ( 6a ) of the forming tool ( 6 ) with the pressure feed connection ( 11 ) and in one of the receiving structure ( 9c ) enclosed area ( 9b ) ends.

Images