DE102019005910A1 - Method and device for producing a component - Google Patents

Abstract

A method and a device for producing a component, in particular a land vehicle, watercraft or aircraft or a rotor blade of a wind power plant, are specified, in which an arrangement (2) made of fibers and plastic is placed in a mold (1) and increased Pressure and elevated temperature (3) are applied, using a mold (1) which has at least one recess (8) in which a reinforcing element (4) is arranged. One would like to have freedom in the choice of a reinforcing element. This is provided that the reinforcing element (4) is arranged together with a core (11) in the recess (8).

Description

The invention relates to a method for producing a component, in particular a land vehicle, watercraft or aircraft or a rotor blade of a wind turbine, in which an arrangement of fibers and plastic is placed in a mold and subjected to increased pressure and temperature Form used which has at least one recess in which a reinforcing element is arranged.

The invention also relates to a device for producing a component, in particular a land vehicle, watercraft or aircraft or a rotor blade of a wind energy installation, with a shape that has a contact surface and a recess in the contact surface, a pressing force generating device being arranged adjacent to the contact surface.

Such a method and apparatus are off DE 10 2017 113 595 A1 known.

When the arrangement of fibers and plastic is subjected to increased pressure and temperature, the plastic melts and then forms a wall or "skin" that is formed by a fiber-reinforced plastic. If this skin is designed as a half-shell, for example, then you can use two such half-shells to build a body or a cabin of a vehicle.

The reinforcement element serves to strengthen this skin, in particular to stiffen it. The reinforcement element is also made of fibers and plastic.

If the arrangement of fibers and plastic in the mold is now subjected to increased pressure and temperature, then not only does the plastic of the arrangement melt, but the reinforcing element is also thermally applied and experiences a temperature increase that leads to softening or even melting of the plastic of the reinforcement element. This is not critical as long as the shape of the recess corresponds to the shape of the reinforcement element.

The invention is based on the object of having certain freedom when choosing a reinforcing element.

In a method of the type mentioned at the outset, this object is achieved in that the reinforcing element is arranged in the recess together with a core.

The core then supports the reinforcing element when the arrangement of fibers and plastic is acted upon and prevents the reinforcing element from being deformed beyond a certain extent. Depending on the choice of the core, a deformation of the reinforcement element can be prevented to a relatively large extent. When the production process has been completed, i.e. the temperature and pressure have been reduced, the skin with the reinforcing element can be removed from the mold and then the core can also be removed. Carbon fibers are preferably used as fibers. The use of glass fibers or other high tensile strength fibers is also possible. The plastic used is preferably a thermoplastic, in particular polyamide, for example PA6. This applies both to the arrangement of fibers and plastic and to the reinforcing element.

In a preferred embodiment, it is provided that a core is used which has a cross-sectional shape that is adapted to a free cross-section that results after the reinforcement element has been inserted into the recess. The more precisely the cross-sectional shape of the mold is adapted to the free cross-section, the lower the possible deformation. However, the correspondence between the shape of the cross-section and the free cross-section does not have to be exact.

A core with a variable volume is preferably used. In many cases, reinforcement elements, also known as “stringers”, are used, which are available as semi-finished products. Such stringers have a relatively large tolerance, i.e. their external dimensions differ noticeably. A core with a variable volume is used in order to be able to produce the components in the same way even with relatively large differences between individual stringers. Due to the variable volume of the core, tolerances in different stringers can be taken into account. Here, too, it is preferred that a core is used which has a cross-sectional shape that is adapted to a free cross-section that results after the reinforcement element has been inserted into the recess. The more precisely the cross-sectional shape of the mold is adapted to the free cross-section, the lower the possible deformation. For example, it can be preferred that the cross-sectional shape corresponds to a reduced copy of the free cross-section, with a circumferential distance being formed between the cross-sectional shape and the free cross-section which has sizes between 0.05 mm and 0.65 mm in some areas.

It is preferred here that a body with a cavity is used as the core pressurized. The body extends parallel to the reinforcement element and accordingly has a certain length. For the sake of simplicity, such a body is referred to below as a “hose”. If the hose is pressurized, it can support the reinforcing element in the recess so that deformation of the reinforcing element can largely be ruled out when the arrangement of fibers and plastic is subjected to increased pressure and temperature.

A body is preferably used which is expandable at least along its circumference. The body can therefore have a cross section that is slightly smaller than the free cross section. When the body is then pressurized, it expands or expands until it can pressurize the reinforcing element. For this purpose it can be preferred that the body is stretched by approximately 0.2% to approximately 2.2%, in particular reversibly.

Alternatively or in addition, it can be provided that a body is used which, before the application of pressure, has at least one fold which extends along the longitudinal extension of the body, which, however, can also include a spiral-shaped circumference, for example. The fold then allows the body to expand beyond its extensibility or, if the body itself is not expandable, the fold allows expansion at all. This can be used to ensure that the body or hose rests against the inside of the recess and against the reinforcing element and pressurizes the reinforcing element.

It is preferable to use a body which is produced by an internal high pressure forming process. In a hydroforming process, the body is placed in a mold that later defines the outer shape of the body. By applying pressure to the cavity, the body is then expanded and given the desired external shape.

A core made of a metal is preferably used. A metal is resistant to an increased temperature and is usually also pressure-resistant. If the core made of metal is to be stretched within the pressing process, i.e. during the time in which the arrangement made of fibers and plastic is subjected to increased pressure and temperature, it is preferred that the one within the mold and the one (correspondingly) within the cavity acting pressure, as well as the wall thickness of the body and its necessary expansion are coordinated in such a way that the core is deformed in the Hook area.
Alternatively, you can use a core made of a plastic, the melting temperature of which is greater than the elevated temperature. A plastic has the advantage that it is generally easier to shape and can therefore be more easily adapted to the shape of the free cross section.

A support strip is preferably arranged between the core and the arrangement made of fibers and plastic. The support bar can be non-deformable. A support strip can be used which is adapted to a geometry which results in the area of the connection between the arrangement of fibers and plastic and the reinforcing element. There is often a gusset here. Strengthening or supporting the gusset counteracts delamination, in particular if the arrangement of fibers and plastic comprises several individual layers in the unpressed state, that is to say, for example, is formed from prepregs or organic sheets arranged one above the other.

It can be preferred that the support strip is designed as a tensioning device. The support strip can be connected to the core or formed separately from the core. The tensioning device preferably has at least one spring element, which is formed, for example, from a textile material made of a heat-resistant material or alternatively comprises an elastic core sheathed with a heat-resistant material. The provision of such a support strip favors ensuring a desired pressure distribution in the component production process. It goes without saying that the device can also comprise a plurality of support strips that act in different spatial directions.

A core is preferably used which has a shape which protrudes into a gusset between the reinforcing element and the arrangement of fibers and plastic. Such a formation can also be provided on a hose, especially if it has been produced by the above-mentioned internal high-pressure forming process. The hose can then have positive and negative radii on its outer circumference.

A mold in which prepregs are placed can, for example, be used to carry out such a process. The prepregs used can be, for example, unidirectional prepregs, that is to say prepregs in which carbon fibers or other reinforcing fibers, such as glass or carbon fibers, all run in the same direction. Alternatively, you can also use prepregs in which reinforcing fibers are arranged in different directions, preferably one for each direction Fiber layer is provided. In order to arrange reinforcing fibers in different directions, one can also arrange several unidirectional prepregs on top of one another and specify a corresponding direction for the reinforcing fibers by aligning the prepregs.

In the case of a prepreg, the reinforcing fibers are pre-impregnated with a plastic. A thermoplastic material, in particular polyamide, for example PA6, is preferably used here.

To apply the increased temperature and pressure, a membrane is used, for example, which delimits an oil pressure chamber. Oil at an elevated temperature, for example in a range from 330.degree. C. to 410.degree. C., can then be fed into the oil pressure chamber. The oil can also be used, for example, to lower the temperature again after heating, for example by cooling the temperature of the oil to a temperature range of 20 ° to 40 ° C., in particular 30 ° C., for example.

The prepregs can be inserted, for example, with the help of tape layers.

In the case of a device of the type mentioned at the outset, the object is achieved in that a deformable core is arranged in the recess.
When the arrangement of fibers and plastic is acted on, the reinforcing element can now be supported by the core and so prevent the reinforcing element from being deformed beyond a certain extent. The core can preferably be elastically deformable, ie it can assume its original shape again after the arrangement of fibers and plastic has been acted upon, during which it is deformed or during which it is deformed.

Preferably, at least 80% of the core is formed from a metal. A metal withstands the high temperature and is usually sufficiently pressure-resistant.

The core is preferably expandable. When the arrangement of fibers and plastic is subjected to increased pressure, the core can be expanded, that is, its volume can be increased somewhat, in order to also apply pressure to the side of the reinforcing element that is otherwise not acted upon. The reinforcement element is then also acted upon with increased pressure from several or even from all sides, the pressure not necessarily having to be the same on all sides. It is important that the build-up and maintenance of effective pressure is made possible in the entire boundary area between the mold, the core and the component to be produced (arranged in between).

It is preferred here that the core has a cavity to which a pressure medium can be applied by a pressure application device. A liquid such as oil can be used as the pressure medium, for example. It is preferably an incompressible pressure medium.

It is also advantageous if the core is movable in the recess and has a pressure connection. You can then insert the core together with the semi-finished product of the reinforcing element into the mold and then establish a connection between the cavity and the pressurizing device via the pressure connection. This makes handling of the core flexible. You can also use different cores, for example with different cross-sectional shapes, that is to say provide an exchangeable core.

In addition, it can be preferred if the device has a handling device for moving the core. This can be particularly advantageous if the device is designed to produce particularly large components, for example with lengths of 10 meters to 30 meters. The core then does not necessarily have to be “inserted” into the mold when the arrangement of fibers and plastic is formed, but can also be “pushed” into the one free cross section afterwards. If the core is designed to be expandable, for example, and has small wall thicknesses, it is advantageous if the handling device is designed such that it can act on the cavity. For this purpose, it can comprise a stabilizing element such as a rod. Alternatively, it can be advantageous if the handling device comprises a control device or is in operative connection with a control device by means of which a pressure acting in the cavity of the core can be controlled in such a way that the shape of the core is stable while it is being introduced (“pushed in”) .

The pressurization device preferably has a temperature control device for the pressure medium. If the pressure medium receives an increased temperature, then the reinforcement element is also subjected to an increased temperature. This can advantageously be used to melt the plastic of the reinforcing element at the same time, for example to keep the production times short. The heat transfer from the core to the reinforcement element takes place more quickly than heat transfer from the side of the contact surface.

The pressing force generating device preferably has a pressure chamber which is delimited by a membrane on its side opposite the contact surface, a control device being provided which coordinates a pressure in the cavity and a pressure in the pressure chamber. This can be achieved, for example, by using the same pressure medium, for example oil or another liquid, for the cavity and the pressure chamber. The pressures in the cavity and in the pressure chamber do not necessarily have to be the same. For example, they can also be set to a predetermined relationship to one another. In this case, pressures in the range between approximately 1.5 bar and 50 bar, very preferably between approximately 2 bar and 30 bar, can develop in the pressure space and in the cavity.

At least one wall section delimiting the cavity preferably has a thickness in the range from 0.05 mm to 0.65 mm. Although this is a relatively small wall thickness. However, it allows sufficient deformation of the core to expand the core. The increase in volume that occurs during expansion can be relatively small. It is in the range from 0.2% to 2.2%.

In this case, it may be preferred in some cases if a first wall section delimiting the cavity and a second wall section delimiting the cavity are configured differently in terms of their thickness. The thickness of at least one wall section falls in the range from 0.05 mm to 0.65 mm. The wall thickness of the core should be stronger in the direction of a reinforcement element than in the direction of the mold.

The core can comprise a cavity or a plurality of cavities separated from one another. If several cavities separated from one another are formed, the cavities can be subjected to different pressures. Expansion of different strengths can then be set on the core in sections. It is also conceivable that an equally strong expansion of different sections of the core can be set, even if the different sections have different thicknesses of the wall sections delimiting the cavities belonging to them.

The core preferably has an outwardly protruding projection. In some cases, when the semi-finished product of the reinforcement element comes into contact with the arrangement of fibers and plastic, a gusset results in which the projection can enter in order to support the reinforcement element here as well. Strengthening or supporting the gusset counteracts delamination, in particular if the arrangement of fibers and plastic comprises several individual layers in the unpressed state, that is, for example, is formed from prepregs or orange sheets arranged one above the other. The hose can then have positive and negative radii on its outer circumference. As already mentioned, it is important that the build-up and maintenance of effective pressure is made possible in the entire boundary area between the mold, the core and the component to be produced (arranged in between).

It is also advantageous if the core has a non-deformable support strip. In this context, this means that the support strip is deformed by less than 0.05% when pressure is applied to the pressure in the pressure space or in the cavity and at a temperature with which the arrangement of fibers and plastic is applied.

• 1 eine erste Ausführungsform eines Kerns,
• 2 eine zweite Ausführungsform eines Kerns,
• 3 eine dritte Ausführungsform eines Kerns mit Stützleiste,
• 4 eine zweite Form eines Verstärkungselements mit einer vierten Form eines Kerns,
• 5 die zweite Ausführungsform des Verstärkungselements mit einer fünften Form eines Kerns und
• 6 eine schematische Darstellung zur Erläuterung der Vorgehensweise beim Einführen und Entnehmen des Kerns.

The invention is described below on the basis of preferred exemplary embodiments in conjunction with the drawing. Show here:

• 1 a first embodiment of a core,
• 2 a second embodiment of a core,
• 3 a third embodiment of a core with a support strip,
• 4th a second shape of a reinforcement element with a fourth shape of a core,
• 5 the second embodiment of the reinforcement element with a fifth shape of a core and
• 6th a schematic representation to explain the procedure for inserting and removing the core.

1 schematically shows a shape 1 into which you can put an arrangement 2 made of fibers and plastic and this arrangement is then subjected to increased pressure and temperature. This is through arrows 3 indicated.

In the arrangement 2 fibers and plastic are preferably one or more prepregs, ie fibers made of carbon (carbon fibers) or other high tensile strength fibers, which are provided with a plastic, preferably a thermoplastic, in particular polyamide, eg PA6. The fibers can be arranged unidirectionally, that is to say they can all run in the same direction. But it is also possible to use prepregs in which there are several fiber layers, the fibers of which run in different directions. You can also use unidirectional prepregs, i.e. prepregs in which all fibers run in the same direction and the multiple prepregs in different directions in the mold 1 arrange. The fiber direction depends on the later desired load capacity of the Component. For example, the component can be used to produce a fuselage or a cabin for a land, water or aircraft.

Form 1 has a contact surface 1a on where the arrangement 2 made of fibers and plastic. In many cases it will be appropriate to use the contact surface 1a in the direction of gravity below the arrangement 2 made of fibers and plastic. The contact surface 1a has a recess 1b on, in which a reinforcing element 4th is arranged. Such a reinforcement element 4th is also known as a "stringer". In the present case, the 1 the reinforcement element is Z-shaped.

The application of the order 2 made of fibers and plastic with increased pressure and temperature is expediently carried out via a membrane 8th , which delimits a pressure chamber (not shown in detail) into which a pressure medium, for example oil, can be fed at an increased pressure and an increased temperature. The membrane 8th is on the contact surface 1a opposite side of the arrangement 2 arranged from fibers and plastic. The membrane 8th is only in 1 shown, but can also be present in the other embodiments.

The reinforcement element 4th has a first leg 5 on who at the arrangement 2 made of fibers and plastic. To simplify the explanation, this arrangement becomes 2 short as "skin 2a " designated. The reinforcement element 4th has a footbridge 6th on that is perpendicular to the skin 2a extends. On the skin 2a remote end of the web 6th is another leg 7th arranged. The recess in the form 1 has a depth equal to the distance between the outer sides of the legs 5 , 7th corresponds. The recess 1a has depressions 9 , 10 on that to the thighs 5 , 7th are adapted.

If now the skin 2a is applied with increased pressure and temperature, then the reinforcing element 4th heated, which can mean that it no longer remains dimensionally stable, but becomes flowable. To avoid deformation is a core 11 with a cavity 12 provided, which can be subjected to a pressure p. The pressure is expediently applied from one end 13 of the core 11 like this in 6th is shown.

Before loading the cavity 12 with pressure there is a wall 14th of the core more or less uncontrolled in the recess 1a , ie it has no defined position. When the cavity 12 however, pressure p has been applied, then the wall rests against the reinforcing element 4th as indicated by the reference number 14a is shown.

The core 11 so has a variable volume. This makes it possible to use the same procedure, even when reinforcing elements 4th different from each other. There are construction tolerances in the range of 5 to 10%.

The core 11 is designed here as a “tube”, ie as a body with a cavity 12 , which is stretchable at least in the circumferential direction. As an alternative or in addition, a fold (not shown in more detail) can also be provided, which extends along the longitudinal extent of the body. The core 11 can be formed from a thin metal which is elastically extensible to some extent according to Hook's law. Such a hose can be produced by an internal high pressure forming process. In the present case, “elastic” means that the volume of the core increases when pressure is applied and decreases again when the pressure p is reduced.

In one area 15th has the reinforcing element 4th a head start 16 on that in a gusset between the wall 14a and the skin 2a protrudes. With such a reinforcing element 4th one can achieve that the reinforcing element 4th through the core 11 is fully pressurized. However, such a reinforcing element is 4th with molding 16 can only be produced with a certain amount of effort and therefore correspondingly expensive.

2 shows an alternative embodiment in which identical and functionally identical elements have been provided with the same reference numerals.

In this case the core points 11 in the area 15th a formation 17th on that in the gusset between the reinforcing element 4th and the skin 2a protrudes. Otherwise the procedure is the same. The tube with its cavity 12 is shared with the reinforcement element 4th into the recess 8th the form 1 inserted. After that the arrangement 2 Made of fibers and plastic inserted into the mold to later make the skin 2a to form and skin 2a is subjected to increased pressure and temperature. At the same time the cavity becomes 12 applied to the pressure p, so that the reinforcing element 4th is supported and practically cannot deform.

3 shows a third variant, in which the same and functionally identical elements are provided with the same reference numerals. Here is between the core 11 and the skin 2a a support bar 18th arranged. The support bar 18th can be designed to be non-deformable. It has a formation 19th on that in the gusset between the reinforcing element 4th and the skin 2a protrudes.

In the 1 to 3 is a Z-shaped reinforcement element 4th shown. The 4th and 5 show an Ω-shaped reinforcing element 4th that shares with the skin 2a encloses a cavity in which the core 11 is arranged. Here, too, the core points 11 again a cavity 12 to which a pressure p can be applied in order to heat and press the skin 2a deformation of the reinforcement element 4th to prevent.

4b shows an enlarged section of the area 15th out 4a . One can see that the reinforcing element 4th is provided with a molding that is in a gusset between the core 11 and the skin 2a protrudes.

5b shows an enlargement of the area 15th out 5a . You can see here that the core 11 a formation 17th having in the gusset between the reinforcing element 4th and the skin 2a protrudes.

Since it is in the refinements 4th and 5 two areas of contact between a reinforcement element 4th and the skin 2a there, the other contact area can be designed accordingly.

6th shows schematically the procedure how to get the core 11 introduces into the reinforcement element. For this purpose, for example, a handling rod 19th provided along with the core 11 into the cavity 12 is introduced. The handling stick 19th can then from the core 11 be pulled out. The core 11 points at the end 13 a threaded connection 14th so that it can be connected to a pressure source in a pressure-tight manner as soon as it is completely in the reinforcing element 4th has been introduced. The pressure p can then be applied to this end.

At the end of the manufacturing process, i.e. when the temperature and pressure have been lowered and the component is out of the mold 1 has been taken, you can see the core 11 pull out.

The component can definitely have a length of several meters, for example a length in the range from 10 to 15 m or more.

The application of increased pressure and increased temperature is preferably carried out via an oil which is introduced into an oil pressure chamber. The oil pressure chamber is of the arrangement 2 made of fibers and plastic, i.e. the skin 2a , separated by a membrane not shown. The oil can have a temperature in the range of 350 ° C to 410 ° C if the elevated temperature is desired. After pressing, i.e. after the application of pressure, the temperature can be reduced to around 30 ° C.

The above prepregs can be made into the mold by hand or by layers of tape 1 be inserted. The thickness of the skin 2a can be adjusted by using more or less prepregs.

The membrane mentioned above can have an R _z value of less than 0.1 μm, so that the skin is extremely smooth 2 results.

The pressure and temperature curve when the arrangement of fibers and plastic is applied in the mold 1 should rise as parallel as possible and decrease again as parallel as possible.

You can now use the arrows 3 symbolized pressure and temperature application of the arrangement 2 Made of fibers and plastic with the pressurization of the cavity 12 control by a common control device not shown. For example, one can see the pressures in the cavity 12 and make the same size in the above-mentioned pressure space or you can set a certain predetermined ratio between these pressures. For example, you can ensure that the pressure in the pressure chamber is always at least 5% greater than the pressure in the cavity 12 .

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• DE 102017113595 A1 [0003]

Claims (21)

Method for producing a component, in particular a land vehicle, watercraft or aircraft or a rotor blade of a wind turbine, in which an arrangement (2) made of fibers and plastic is placed in a mold (1) and subjected to increased pressure and temperature (3) applied, using a mold (1) which has at least one recess (8) in which a reinforcing element (4) is arranged, characterized in that the reinforcing element (4) together with a core (11) in the recess (8) orders. Procedure according to Claim 1 , characterized in that a core (11) is used which has a cross-sectional shape which is adapted to a free cross-section which results after the reinforcement element (4) has been inserted into the recess (8). Procedure according to Claim 1 or 2 , characterized in that a core (11) with a variable volume is used. Procedure according to Claim 3 , characterized in that a body with a cavity (12) is used as core (11), to which pressure (p) is applied. Procedure according to Claim 4 , characterized in that one uses a body which is stretchable at least along its circumference. Procedure according to Claim 4 or 5 , characterized in that a body is used which, before the application of pressure, has at least one fold which extends along the longitudinal extent of the body. Method according to one of the Claims 4 to 6th , characterized in that a body is used which is produced by an internal high pressure forming process. Method according to one of the Claims 1 to 7th , characterized in that a core (11) made of a metal is used. Method according to one of the Claims 1 to 7th , characterized in that a core (11) made of a plastic is used, the melting temperature of which is greater than the elevated temperature. Method according to one of the Claims 1 to 9 , characterized in that a support strip (18) is arranged between the core (11) and the arrangement (2) made of fibers and plastic. Method according to one of the Claims 1 to 10 , characterized in that a core (11) is used which has a recess (17) which protrudes into a gusset between the reinforcing element (4) and the arrangement (2) made of fibers and plastic. Device for producing a component, in particular a land vehicle, watercraft or aircraft or a rotor blade of a wind turbine, with a shape (1) which has a contact surface (1a) and a recess (1b) in the contact surface (1a), the A pressing force generating device (3) is arranged adjacent to the contact surface (1a), characterized in that a deformable core (11) is arranged in the recess (1b). Device according to Claim 12 , characterized in that the core (11) is formed to at least 80% of a metal. Device according to Claim 12 or 13 , characterized in that the core (11) is expandable. Device according to Claim 14 , characterized in that the core (11) has a cavity (12) to which a pressure medium can be applied by a pressure application device. Device according to Claim 15 , characterized in that the core (11) is movable in the recess (1b) and has a pressure connection. Device according to Claim 15 or 16 , characterized in that the pressure application device has a temperature control device for the pressure medium. Device according to one of the Claims 15 to 17th , characterized in that the pressing force generating device (3) has a pressure chamber which is delimited on its side opposite the contact surface by a membrane (8), a control device being provided which applies a pressure in the cavity (12) and a pressure in the pressure chamber to one another votes. Device according to one of the Claims 15 to 18th , characterized in that at least one wall section delimiting the cavity (12) has a thickness in the range from 0.05 mm to 2.5 mm. Device according to one of the Claims 12 to 19th , characterized in that the core (11) has an outwardly protruding projection (17). Device according to one of the Claims 12 to 20th , characterized in that the core (11) has a non-deformable support strip (18).

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