DE102017113928A1 - Fiber composite component and an apparatus and a method for producing a fiber composite component - Google Patents

Abstract

The invention relates to a fiber composite component having an outer molding side, comprising an outer pipe (5) with an end-side, inner connecting element (6), wherein the pipe (5) is formed as a fiber composite pipe of fiber layers and a matrix material and the connecting element (6) has a connection region ( 14) and a connection region (7) and in that the tube (5) is connected to the connection element (6) over at least part of the connection region (7), which is characterized in that the connection region (7) of the connection element (6) Having means for positive fixing of the tube (5).

Description

The invention relates to a fiber composite component with an external molding side, in particular a fiber composite pipe with an external molding side and an internal flange connection. Furthermore, the invention relates to an apparatus and a Schlauchblasverfahren for producing the fiber composite component.

The fiber composite component preferably consists of tubes with continuous fiber-reinforced plastic laminates and contains prefabricated force introduction elements. In this case, the fiber composite tube itself is formed from fiber layers and the matrix material, which end has a connection element in the form of a sleeve and in particular a flange sleeve. The connection element is preferably formed from a rigid material, such as metal or a suitable plastic. Fiber composite pipes are predominantly produced by winding the fiber layers with the matrix material onto a mold core. The impression side is thus internal, since the shape is arranged as a core in the interior of the tube. In contrast, the invention relates to fiber composite components with an outer molding side, wherein the shaping of the outer contour of the component is effected by the externally arranged mold. Such fiber composite components are produced for example by the Schlauchblasverfahren.

In the prior art, generic fiber composite components with connection elements in the application as waves for various applications are already widely used.

So goes for example from the DE 30 07 896 A1 a connection connection for fiber plastic tubes, in particular as hollow shafts of motor vehicles. In this case, a non-fiber composite plastic connecting element is connected via a circumferential toothing in the direction of rotation form-fitting manner with the hollow shaft made of fiber plastic.

The DE 101 36 707 B4 discloses a propeller shaft and method of making the same. In this case, the toothing of the connecting element intersects by pressing into the fiber composite tube and there is a very durable positive connection.

Another application is in the DE 10 2007 018 082 A1 discloses a transmission shaft made of fiber composite materials, which is used in particular for driving the wing flaps of an aircraft and which is composed of one or more carbon fiber layers and one or more fiberglass layers.

Also known is the connection of fiber composite components with each other or with other components and in particular of fiber composite pipes with other components or pipes via flange connections.
From the DE 10 2015 112 173 A1 is a connection part for a tubular member made of fiber reinforced plastic and a process for its preparation. In this case, a connection element is positively connected using a connection element with the flange for receiving the mechanical loads on the end face of the flange.

After DE 101 48 950 A1 a CFRP structure with force introduction elements is disclosed. The force introduction elements are tubular or formed as a hollow profile with a deviating from the ring profile cross-section and are each widened at one end to a flange.

From the DE 10 2008 028 337 B4 a method for producing a hollow shaft is described with at least one integral flange made of fiber composite material. The method of manufacturing is carried out via the winding of the fiber composite material via a core to a hollow shaft, wherein an integral flange made of fiber composite material or of the material of the hollow shaft is performed.

The aforementioned embodiments of the prior art differ in their construction. The so-called fully integral design is characterized by molded force introduction elements. The partially integral construction is characterized by the connection of prefabricated flanges in the shot-in process. After the latter technology, a distinction is again made after the connection of the connection element.
In the case of an outer mold side, a flange connection with an external or internal connection of the connecting element is possible.

From the DE 10 2005 020 907 A1 goes out a hollow structure made of fiber reinforced plastic with load introduction elements, which creates an external flange connection with the outer mold side of the tube in the inflation process.

Furthermore, internal Flanschanbindungen with internal mold side, for example in überflochtenen flanges, known in the art.

All in all, it can be stated that various approaches exist for the production of fiber composite components with connection elements such as flanges. However, these approaches have inherent disadvantages.

The differential design is associated, for example, with subsequent assembly steps and the sometimes complex processing of the individual components in preparation for assembly.

The fully integrated design sometimes leads to a very complex, difficult-to-manufacture component architecture.
The inclusion of high point loads through fiber composite structures is generally difficult and sometimes not possible due to space limitations.

Although the external flange connection in the shot-in process leads to good results, but requires a complex production of positive force introduction elements on the harder to process inside of the flange.

The internal flange connection with internal mold side in turn requires the combination with the stack winding method, for example according to the DE 10 2012 104 370 A1 for efficient production of the pipes. In addition, consolidation of the laminate during the heat treatment upsets the outer laminate layers, thereby limiting the load bearing capacity of the fiber composite structure.

The object of the invention is therefore to transmit material by means of a cost-effective design high loads in fiber composite pipes.

The object is achieved by an object having the features of the independent claims. Further developments are specified in the dependent claims.

The object of the invention is achieved in particular by a fiber composite component with an external molding side, which has an outer pipe with an end-side, inner connection element. The tube is formed as a fiber composite tube of fiber layers and a matrix material.

The connection element is formed from a rigid prefabricated material and has distally a connection region, for example in the form of a flange, and opposite a connection region for connection to the tube. The tube is connected to the connection element via at least part of the connection region. The connecting region of the connecting element has means for the positive fixing of the tube.

Preferably, the connection region of the connection element has external form elements for the positive connection of pipe and connection element.

Advantageously, grooves, threads, toothings or knurls in the connection region of the connection element are formed or formed or formed as external form elements.

According to a particularly advantageous embodiment of the invention, the connecting portion of the connecting element is formed radially expandable as a means of positive fixing of the tube.

According to a further advantageous embodiment, the connection element in the connection region on at least one breakthrough for receiving and the passage of matrix material as a means of positive fixing of the tube.

The connecting element in the connecting region advantageously has slots which form tabs as a means of the positive fixing of connection element and pipe after the pressurization.

As means of the positive fixing of the tube meandering slots are advantageously formed in the connecting region of the connecting element.

The invention is further achieved by a device for producing fiber composite components, which has an upper mold half and a lower mold half, which together form a cylindrical receptacle for the tube of fiber layers and matrix material and a receptacle for the connection element. The connection element is arranged at the end of the tube. Furthermore, a pressure hose is accommodated in the interior of the receptacle of the mold halves, wherein in the connection region of the connection element in the radial direction from the inside to the outside of the pressure hose, the connection element, the tube and finally the mold half are arranged completely outside. Between the connection element and the mold half, a cavity is formed in the connection region. Under a cavity in the context of the invention is to be filled cavity to be understood, which is slit-shaped or slit-shaped. Particularly preferably, the slot is designed as a cavity in the circumferential direction of the connecting element.

When the pressure is applied by means of the pressure hose, a pressure shadow in the radial direction forms behind the connection element in the cavity, which is advantageously filled in the axial direction with the liquefied matrix material of the fiber composite material. The matrix material, For example, the synthetic resin, surrounds the outside of the connection element and forms a positive connection with the mold elements on the outside of the connection element after curing of the matrix material. Thus, the developing print shadow, which is disadvantageous in methods according to the prior art, in the present case is advantageously used in order to form a three-dimensional space for positive connection via the resulting cavity filled with matrix material.

According to an alternative embodiment of the invention, the cavity is formed reducible when pressurized by means of the pressure hose by radially widening of the connecting portion and a positive connection is formed by the expansion.

Advantageously, the cavity is designed to be fillable by means of the pressure hose via recesses or slots in the radial direction with the matrix material. The liquefied matrix material passes via the recesses or slots from the outside to the inside of the connecting region of the connecting element and thus forms webs after curing, which form the positive connection for connection of connecting element and fiber composite pipe.

To improve the effect and ensure the fullest possible filling of the cavity with matrix material, a reservoir of matrix material, for example in the form of an adhesive film or adhesive ring on the inside of the connection element, is executed in the connection region of the connection element.

Particularly preferably, the individual effects for forming a three-dimensional positive connection of connection element and fiber composite pipe can be combined. In this case, for example, through slots in the connection region of the connection element, the passage of matrix materials from outside to inside and vice versa is possible. Furthermore, by suitable design of the slots in the axial direction, a widening of the connecting area with additional effect of the positive engagement of the connection. The formation of tabs in the connection region of the connection element and the arrangement of form elements on the outer circumference of the connection element further enhance the positive engagement of the connection.

The form elements, recesses or slots in the connection region of the connection element are preferably made by punching, milling or laser treatment.

The invention is further achieved by a tubular blowing process for the production of fiber composite components, wherein a scrim of fiber layers is placed with a matrix material in a mold, a connection element is introduced into the mold such that a cavity between the connection element and the mold can be formed, a pressure hose is introduced into the mold such that upon pressurization of the pressure hose, the scrim of fiber layers with the matrix material presses against the mold and the cavity is subsequently reduced in size and / or filled with matrix material.
Advantageously, an adhesive film of matrix material, for example as a resin layer, as an additional matrix material on the inside of the connection element in the connection region for filling the cavity after melting of the adhesive film is further positioned.

The concept of the invention consists essentially in the fact that in the production of fiber composite pipes with an external mold side, a blank made of fiber layers and pressed during the heat treatment step by means of the tubular blowing against the outer mold halves. As the blank, a pressure-elastic or thermoplastic prepreg, hybrid yarn or the like can be used. Likewise usable is a semifinished product premixed with a matrix material. Optionally, the pressing process can be carried out with the pressure hose with a support by vacuum, for which the mold must be prepared according to vacuum-tight.

As a result of the pressing process, the fiber layers of the blank are set from the inside to the outside, whereby the fiber layers are consolidated to form a nonporous laminate. Particularly advantageously, the tube produced is connected to a sleeve as a connection element, which rests against the inner surface of the fiber composite and thus can transfer loads into the tube. However, an internal sleeve has the disadvantage that it hampers the setting process for the consolidation of the fiber layers by the formation of a print shadow in the radial direction.
However, this effect is advantageously used according to the invention to produce a three-dimensional form-fitting composite of connection element and fiber composite pipe.
Particularly advantageous in the proposed method and the device and the fiber composite component itself is that a liberated by the setting cavity between the connection element, the sleeve or the flange, and the outer mold halves is filled by additional matrix material, which is the composite of connecting element and fiber composite pipe significantly improved.
Alternatively or in addition to this effect, the connection element, the sleeve or the flange For example, designed even radially expandable. Again alternatively or cumulatively, in the region of the connection element, backward-looking molded parts are provided from outside to inside. The fiber volume content may change locally. The additional matrix material either comes from the regions of the fiber composite tube adjacent to the flange and is pressed into the region between flange and mold halves by an axial flow movement.
Furthermore, the additional matrix material can be positioned as additional material within the connection element and can be pressed radially outward through the openings through openings in the connection region of the connection element by means of the pressure hose, which is also referred to as blow hose.

The connection element can alternatively or additionally be designed by a design with slots such that it is radially expandable. This supports the effect of filling the volume released. In addition, a fine toothing between the connection element in the connection region and the tube is created. Through the slots also a radial feed additional matrix material can be realized.
As a further advantageous option, the volume of the cavity can be filled by movable moldings, which are pressed in the region of the flange during the heat treatment step from outside to inside. The sleeve is designed in an advantageous embodiment so that it has cylindrical and non-cylindrical shape elements at its contact surface to the fiber composite tube. In the heat treatment step, these mold elements are then enclosed with the matrix material and the fiber layers and, after curing of the matrix, lead to a non-detachable, form-fitting joining connection between fiber composite pipe and flange, the connection element.
As a form of elements grooves, threads, gears, knurls and the like can be performed, which are particularly easy and inexpensive to produce on the outer contact surface.

The advantages of the invention are very diverse. The fiber composite component as a fiber composite tube with a form-fitting connected connection element improves the failure safety of the connection. Especially for flange connections, the improvement of the force introduction characteristic is of high value.

The inner flange is advantageously used in tight spaces and the Schlauchblasverfahren generally supports the stretched fiber flow without upsetting, resulting in very good structural properties of the fiber composite component.
The heat input for the heat treatment step is advantageously possible via an external, temperable mold. This allows the simple application of the hot pressing process with comparatively low cycle times and excellent efficiency.

• 1: Vorrichtung zur Herstellung eines Faserverbundbauteils im Querschnitt
• 2: Vorrichtung mit Faserverbundbauteil im Längsschnitt
• 3: Vorrichtung und Faserverbundbauteil mit Ausnehmungen im Erfindungsbereich des Anschlusselementes im Querschnitt
• 4: Anschlusselement mit Verbindungsbereich und Anschlussbereich.

Further details, features and advantages of embodiments of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Show it:

• 1 : Device for producing a fiber composite component in cross section
• 2 : Device with fiber composite component in longitudinal section
• 3 : Device and fiber composite component with recesses in the invention range of the connection element in cross section
• 4 : Connection element with connection area and connection area.

In 1 a device for producing a fiber composite component according to the invention is shown in cross section. The forms of the device are composed of an upper mold half 1 , a lower half of the mold 2 as well as two moldings 3 , The mold halves 1 . 2 and the moldings 3 the outer mold form a hollow cylindrical interior, in which, adjacent to the mold halves, the tube 5 is lined with fiber layers and matrix material as a scrim. Central to the inside of the hollow cylindrical interior is the pressure hose 4 arranged from a flexible material over which the pressing process is carried out in the tubular blowing process. Between the pressure hose 4 and the tube 5 with fiber layers and the matrix material is the connection element 6 arranged, which is referred to as a rigid, partially cylindrical body, also called a sleeve or flange sleeve, is inserted into the mold. In relation to the pipe 5 is the connection element 6 arranged on the inside.
The pressure hose 4 is indicated by small arrows in the radial direction, acted upon by pressure and can increase in volume radially, whereby the fiber layers of the tube 5 to the shape 1 . 2 . 3 pressed, consolidated and consolidated.

In 2 is the in 1 shown device shown in longitudinal section, with only the lower mold half 2 the shape and the lower part of the pressure hose 4 was shown in principle.
The pipe 5 with the fiber layers and the matrix material is completely shown in longitudinal section and in the lower half of the device is the pressure hose 4 shown with the radial pressure acting on it. The connection element 6 is as a rigid, load-bearing part with a connection area 14 and a connection area 7 designed and shaped 1 . 2 . 3 inserted. In the connection area 7 of the connection element 6 forms between the connection element 6 and the lower half of the mold 2 as shown, a cavity 8th , This rigid cavity is located in the pressure shadow of the connection element 6 , After heating and pressurization of the device and the fiber layers, there is now a resin flow in the resin flow direction 9 in the axial direction, through which the cavity 8th with resin from the adjoining the connection region areas of the tube 5 is filled. At the connection element 6 are in the connection area 7 arranged on the outer circumference form elements, which in the matrix material of the fiber composite tube 5 , the resin, embedded and thus anchored form-fitting. Thus, after hardening of the matrix material, a form-fitting, firm connection is produced, which is extremely resilient both in the circumferential direction and in the axial direction.

In 3 is a further embodiment of the anchoring of the connection element 6 with the pipe 5 shown. Here are in the connection element 6 in the area of the connection area 7 breakthroughs 10 , Also referred to as recesses, in the Flanschhülse or in the connection element 6 executed. Through these recesses, which are preferably carried out several times in the circumferential direction, the resin enters in both directions, depending on the circumstances. In a radially rigid connection element 6 can the liquefied matrix material from the outside after filling the cavity 8th into the breakthroughs 10 enter. Furthermore, it is intended to provide additional matrix material so that matrix material can also flow from the inside to the outside. This is an adhesive film 11 as a resin layer on the inner circumference of the connecting element 6 in the connection area 7 formed, which after melting and by the pressure in the interior in the radial direction through the recess 10 into the cavity 8th is pressed into it.

In 4 is a connection element 6 shown which with a connection area 14 and a connection area 7 is equipped, wherein the two areas have different diameters and are interconnected by a conical intermediate piece. In the connection area 7 are slots 12 formed, which the connection element 6 in the connection area 7 to tabs 13 profile, which move through the pressure in the manufacturing process of the fiber composite components in the radial direction, so that by appropriate undercuts and the recording and the passage of matrix material in the connection area 7 a positive connection in the connection area 7 with the pipe, not shown here 5 he follows.

The individual measures for producing the positive locking, which are described above in various exemplary embodiments, are preferably combined with one another. Particularly advantageous is the design of the outer surface of the connection element 6 in the connection area 7 with shaper elements, such as a knurl, a serration, a thread or grooves.

LIST OF REFERENCE NUMBERS

1

upper mold half

2

lower mold half

3

engageable moldings

4

pressure hose

5

Tube with fiber layers and matrix material

6

Connection element, sleeve, flange sleeve

7

connecting area

8th

Rigid cavity in the print shadow

9

Resin flow direction

10

Breakthrough, recess in flange sleeve

11

Adhesive film, resin layer

12

slot

13

flap

14

terminal area

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3007896 A1 [0004]
• DE 10136707 B4 [0005]
• DE 102007018082 A1 [0006]
• DE 102015112173 A1 [0007]
• DE 10148950 A1 [0008]
• DE 102008028337 B4 [0009]
• DE 102005020907 A1 [0011]
• DE 102012104370 A1 [0017]

Claims (13)

Fiber composite component with external molding side, comprising an outer tube (5) with an end, inner connection element (6), wherein the tube (5) is formed as fiber composite tube of fiber layers and a matrix material and the connection element (6) has a connection region (14) and a Has connecting region (7) and that the tube (5) at least over a part of the connection region (7) with the connection element (6) is connected, characterized in that the connection region (7) of the connection element (6) means for positive fixing of the tube (5). Fiber composite component after Claim 1 , characterized in that the connecting region (7) of the connecting element (6) has outer mold elements for the positive connection of the tube (5) and connecting element (6). Fiber composite component after Claim 2 , characterized in that formed as external form elements grooves, threads, teeth or knurls in the connecting region (7) of the connecting element (6). Fiber composite component according to one of Claims 1 to 3 , characterized in that the connecting region (7) of the connecting element (6) is designed to be radially expandable as a means of the positive fixing of the tube (5). Fiber composite component according to one of Claims 1 to 4 , characterized in that the connecting element (6) in the connecting region (7) has at least one opening (10) for the reception and passage of matrix material as a means of positive fixing of the tube (5). Fiber composite component according to one of Claims 1 to 5 , characterized in that the connecting element (6) in the connecting region (7) has slots (12), the tabs (13) as a means of positive fixing of connection element (6) and tube (5) form after pressurization. Fiber composite component according to one of Claims 1 to 6 , characterized in that meander-shaped slots (12) in the connecting region (7) of the connecting element (6) are formed as a means of positive fixing of the tube (5). Device for the production of fiber composite components according to one of the preceding claims, characterized in that an upper mold half (1) and a lower mold half (2) a cylindrical receptacle for the tube (5) of fiber layers and matrix material and a receptacle for the connecting element (6) form, wherein the connecting element (6) end to the tube (5) is arranged and that in the connection region (7) in the radial direction from the inside to the outside a pressure hose (4), the connecting element (6), the tube (5) and the mold half (1, 2) are arranged and that between the connection element (6) and the mold half (1, 2) in the connection region (7) has a cavity (8) is formed. Device after Claim 8 , characterized in that in the cavity (8) upon pressurization by means of the pressure hose (4) a pressure shadow can be formed and filled in the axial direction with matrix material. Device after Claim 8 , characterized in that the cavity (8) when pressurized by means of the pressure hose (4) by radial expansion of the connecting portion (7) is made smaller in size. Device according to one of Claims 8 to 10 , characterized in that the cavity (8) upon pressurization by means of the pressure hose (4) via recesses (10) or slots (12) in the radial direction with matrix material can be filled. Hose blowing method for the production of fiber composite components according to one of the preceding claims by means of a device according to one of the preceding claims, characterized in that - a scrim made of fiber layers with a matrix material in a mold (1,2,3) is inserted, - a connection element (6) is introduced into the mold (1, 2, 3) in such a way that a cavity (8) can be formed between the connection element (6) and the mold (1, 2, 3), - a pressure hose (4) into the mold (1 , 2,3) is introduced such that upon pressurization of the pressure hose (4) presses the scrim of fiber layers with the matrix materials against the mold (1,2,3) and - the cavity (8) subsequently reduced and / or with matrix material is completed. Schlauchblasverfahren after Claim 12 , characterized in that an adhesive film (11) as a resin layer as an additional matrix material on the inside of the connecting element (6) in the connection region (7) for filling the cavity (8) after melting of the adhesive film (11) is positioned.

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