DE102016209702A1 - Method and device for producing a structural component and structural component - Google Patents

Abstract

The present invention relates to a method for producing a load-optimized structural component (1) in a predefined reinforcement region with the method steps: providing a hollow component (2) with a component wall (3), at least one inner cavity (4) surrounded by the component wall (3) and at least one access opening (5) penetrating the component wall (3) from outside to the cavity (4), introducing a flowable foam material into the cavity via the at least one access opening (5), wherein the foam material is formed, in an exothermic reaction reacting a pressure-stable and / or energy-absorbing, solid foam (6), distributing the foam material at least within the reinforcement region of the cavity (4), foaming the foam material into a solid foam (6) such that the foam (6) is at least in the reinforcing region of the hollow component (2), the cavity (4) completely fills as well as in the reinforcing region, the component wall (3) continuously contacted surface, and - monitoring heating of the component wall (3) via the reinforcing region by means of a heat detection device (14). Furthermore, the invention relates to a structural component (1) and to a device (10) for producing a structural component (1) which is optimized in terms of stress in a reinforcement region.

Description

The present invention relates to a method and a device for producing a load-optimized structural component in a reinforcement region, in particular a fiber composite structural component. Furthermore, the invention relates to a load-optimized in a gain range structural component, in particular fiber composite structural component.

In many high technologies, such as In aircraft construction or automotive engineering, structural components are formed as composite components made of composite materials, since composite components combine advantageous physical properties of the individual composite materials. Composite components have, for example, a foam core, which is surrounded by a cover layer to improve a load capacity, in particular a mechanical and / or thermal and / or chemical resistance or the like. For example, the topsheet may be a scrim or braid of fibers such as fibers. Glass fibers, carbon fibers, aramid fibers or the like, coated with a curable matrix material, e.g. a resin, impregnated or interspersed. In this way, for example, a particularly lightweight structural component with high mechanical strength can be produced. The function of the foam core in such structural components is essentially the reduction of component vibrations, in particular by damping due to a somewhat resilient foam structure, and thus of driving noise to increase driving comfort.

To produce such composite components, structural foams are used, for example, since they have a relatively low density and dimensional stability. In many applications, the structural foams are therefore designed as rigid foams with only a low, in particular microscopic, compliance. The structural foam may e.g. be coated with a scrim or braid of fibers, which are impregnated or interspersed with the matrix material, for example by a Resin Transfer Molding process, which is also referred to as RTM process. According to alternative methods for reducing component vibrations of thin sheets, it is known to inject foam material components into intermediate spaces between components, in particular sheet metal. These methods are used in particular for reducing vibrations in thin sheets.

Known methods for the production of structural components with foam cores have the disadvantage that they have a very complicated process control and therefore cause very high production costs. Furthermore, only vibration-damping structural components can be produced by means of these methods. Structural components with a particularly improved energy absorption or compressive strength can not be produced by the known methods.

It is therefore an object of the present invention to remedy the disadvantages described above in a method and an apparatus for producing a structural component, in particular a fiber composite structural component, and in a structural component, in particular a fiber composite structural component, or at least partially. In particular, it is an object of the present invention to provide a method and an apparatus for producing a structural component, which ensure the production of a load-optimized structural component in a reinforcement region in a simple and inexpensive manner and thus improve an energy absorption capacity and / or pressure resistance in a fiber composite structural component , Furthermore, it is the object of the present invention to provide a structural component with an improved energy absorption capacity and / or pressure resistance.

The above problem is solved by the claims. Accordingly, the object is achieved by a method for producing a load-optimized in a gain range structural component having the features of claim 1, by a structural component having the features of claim 12 and an apparatus for producing a load-optimized in a gain range structural component having the features of claim 14. Further features and details of the invention will become apparent from the dependent claims, the description and the drawings. In this case, features and details that are described in connection with the inventive method, of course, also in connection with the structural component according to the invention and the device according to the invention and in each case vice versa, so that with respect to the disclosure of the individual aspects of the invention always reciprocal reference is or may be.

• – Bereitstellen eines Grundhohlbauteils mit einer Bauteilwand, mindestens eine von der Bauteilwand umgebene innere Kavität sowie mindestens eine die Bauteilwand von außen bis zur Kavität durchdringende Zugangsöffnung,
• – Einbringen eines fließfähigen Schaummaterials in die Kavität über die mindestens eine Zugangsöffnung, wobei das Schaummaterial ausgebildet ist, in einer exothermen Reaktion zu einem druckstabilen und/oder energieabsorbierenden, festen Schaum zu reagieren,
• – Verteilen des Schaummaterials zumindest innerhalb des Verstärkungsbereichs der Kavität,
• – Aufschäumen des Schaummaterials zu einem festen Schaum derart, dass der Schaum zumindest in dem Verstärkungsbereich des Grundhohlbauteils die Kavität vollständig ausfüllt sowie im Verstärkungsbereich die Bauteilwand durchgängig flächig kontaktiert, und
• – Überwachen einer Erwärmung der Bauteilwand über den Verstärkungsbereich mittels einer Wärmedetektionsvorrichtung.

According to the first aspect of the invention, the object is achieved by a method for producing a load-optimized in a predefined gain range structural component. The method comprises the following steps:

• Providing a base hollow component with a component wall, at least one inner cavity surrounded by the component wall and at least one access opening penetrating the component wall from the outside to the cavity,
• - Introducing a flowable foam material in the cavity over the at least one Access port, wherein the foam material is adapted to react in an exothermic reaction to a pressure-stable and / or energy-absorbing, solid foam,
• Distributing the foam material at least within the reinforcement area of the cavity,
• Foaming the foam material into a solid foam such that the foam completely fills the cavity at least in the reinforcing region of the base hollow component and contacts the component wall in a continuous manner in the reinforcing region, and
• - Monitoring a heating of the component wall over the gain region by means of a heat detection device.

The basic hollow component provided can, for example, consist of a plurality of individual structures that are joined together to form the base hollow component. It can be provided that during assembly individual cavities of the individual structures are combined to form the inner cavity of the base hollow component. Alternatively, the basic hollow component is also formed in one piece. The base hollow component has at least one access opening, preferably a plurality of access openings, which connect the inner cavity to an environment of the base hollow component. The access openings are preferably arranged on one side of the base hollow member, e.g. a side, which is preferably not a visible side and is preferably arranged for introducing the foam material facing upwards, so that the flowable foam material can not easily flow out of the access opening. Any further openings through which the flowable and / or the foaming foam material could escape from the cavity of the base hollow component are preferably sealed or sealed according to the invention. The base member may be formed, for example, cup-shaped, so that when filling the cavity, one side of the cavity may also be open, which is at least limited by no continuous component wall. When providing the base hollow component is preferably fixed in position, so that a position of the at least one access opening is fixed. A layer according to the invention is understood to mean a position and an orientation. The cavity has an actual shape in the reinforcement region, which corresponds to a desired shape of the foamed foam material. It may be provided according to the invention also moving the Grundhohlbauteils for better distribution of the flowable foam material. The basic hollow component or the component wall may comprise, for example, sheet metal, plastic or the like.

The structural component to be produced has in the reinforcement region a foam core made of a pressure-stable and / or energy-absorbing foam, which is surrounded by a component wall. A reinforcing region is understood according to the invention to mean a region of the structural component which is designed to be optimized for the load by the foam. It may therefore be provided according to the invention that only a part of the structural component, namely the reinforcing region, is formed in this way and another part of the structural component has a different design.

The introduction of the flowable foam material in the cavity of the base hollow member via the at least one access opening, can also be made at several access openings on several, preferably all, access openings. Thus, a uniform distribution of the foam material within the cavity can be improved. The foam material preferably comprises polyurethane (PU) or the like. The foam which can be produced with the foam material preferably has a relatively high hardness and density. Preferably, the foam material is provided with further ingredients which improve or increase, for example, a pressure stability and / or energy absorption capacity of the foam. Further, the foam material is configured to foam in an exothermic reaction to the foam. This means that the foam material can be foamed by activation with release of heat. Further preferably, it may be provided that the foam which can be produced with the foam material is additionally designed to damp vibration and / or sound-insulating.

Since the foam due to the pores usually has a greater specific volume or a lower specific gravity than the foam material, the reinforcing region of the cavity is preferably not completely filled with the foam material, in particular a maximum internal pressure within the cavity and thus an excessive pressure load on the Grundhohlbauteil, or to avoid the component walls of the base hollow component. Furthermore, excessive filling of the cavity could hinder complete or even foaming if necessary. Alternatively, it may be provided that excess foam material, e.g. through the access opening and / or an opening provided for this, escape from the cavity or can be displaced. Alternatively, it can be provided according to the invention that the excess foam material escapes or is displaced from the cavity of the reinforcement region into an adjacent part of the cavity.

When foaming the foam material to the solid foam, at least the reinforcement region of the cavity is completely filled with the solid foam, so that in the reinforcement region the foam contacts the component wall in a planar manner. Surface contact means in the context of the invention that the foam is applied to the component wall, wherein no larger pores or air pockets are formed as the pores of the foam on the component wall. Accordingly, in the reinforcement region, an outer contour of the foam corresponds to an outer contour of the cavity. An exerted on the outside of the component wall pressure is thus evenly on or in the foam forwarded. The foam thus provides an abutment for the component wall. In this way, a punctual overloading of the component wall due to an external force can be avoided.

Since the foaming of the foam material takes place in an exothermic reaction and the foam produced contacts the component wall or is pressed against the component wall, heat is transferred from the foam to the component wall. Ideally, this takes place uniformly, namely when the foam in the reinforcing region lies flat against the component wall. In the event that the foam in the reinforcing region is not formed correctly and the component wall is not contacted or not contacted correctly at one point, a weaker heat transfer from the foam to the component wall takes place at this point. The component wall therefore has a lower temperature at this point than at the locations which are in contact with the foam. Such a temperature difference is detectable in monitoring the heating by means of the heat detection device, such as preferably an infrared camera. Due to the detected temperature difference thus structural components are not identifiable with not properly trained foam core. With a corresponding technical effort, defects of the foam of a few square millimeters, such as 100 mm ² , are already detectable.

The method according to the invention for producing a structural component that is optimized in terms of stress in a reinforcement region has the advantage over conventional methods that it is possible to produce a structural component that is optimized by a foam with simple means and cost-effectively. By monitoring the temperature of the component wall faulty structural components are easily, reliably and inexpensively identifiable and then sorted out. This is particularly important for safety-related structural components in the automotive or aircraft construction of great importance. Elaborate x-ray techniques (such as CT) to detect faults in the foam are not required.

It is preferable that the base hollow member is provided such that at least the reinforcing portion of the base hollow member is disposed in a receiving cavity of a closable receiving mold and the receiving mold is then closed, the receiving cavity having a shape and size corresponding to a shape and size of the reinforcing portion of the base hollow member corresponds or at least substantially corresponds. Preferably, the receiving cavity is formed for accurately fitting the gain region. The receiving form is preferably stationary and can be arranged at least in two parts, so that the reinforcing region of the base hollow component can be received in a form-fitting manner by the receiving mold and can be fixed in position. Preferably, the complete basic hollow component is arranged in a form-fitting manner in the receiving cavity. The closing of the receiving mold can take place, for example, before the introduction of the liquid foam material. Alternatively it can be provided that only the foam material is introduced and then the receiving mold is closed. In this case, it is preferred that the base hollow member is fixed to the open receiving mold via fixing means prior to introducing the foam material. For monitoring the heating of the component wall, the structural component produced is preferably removed from the receiving mold or at least the receiving mold is opened. Such an arrangement of the base hollow component in the receiving form has the particular advantage that the base hollow component is easily, with simple means and well reproducible true to size fixable.

More preferably, the receiving mold is cooled to dissipate the heat generated during foaming. This is preferably done via a cooling device having at least one cooling channel, which is formed in the receiving mold and is flowed through for cooling by a cooling fluid. The heat generated during foaming is thus forwarded via the component wall to the receiving mold and the cooling fluid. A cooling is particularly advantageous if the component wall has a material which has a relatively low thermal load and could be damaged by the resulting heat during foaming. By cooling, the component wall can be easily protected against excessive thermal stress.

Preferably, the receiving cavity is designed such that, in the closed state of the receiving mold, an expansion of the basic hollow component is limited in a form-fitting manner. The receiving cavity is preferably tolerated according to a fit to the basic hollow component. By foaming an internal pressure can be increased within the cavity in the gain region. The foam is pressed from the inside against the component wall. As a result, very high tensile stresses can occur in the component wall, as a result of which the base hollow component or the structural component produced can be damaged: it can deform, break or tear, for example. By such a training of Recording form, the structure of the hollow component or the structural component in a cost-effective manner during foaming much less mechanically loaded because pressure forces are passed from the foam over the component wall directly to the receiving mold. The component wall is thus essentially loaded only on pressure, while in the component wall no or only very low tensile stresses occur.

It is inventively preferred that the entire basic hollow component is arranged in the receiving cavity. Furthermore, it can be provided that the reinforcement region extends over the entire or substantially over the entire base hollow component. The inclusion of the entire base hollow component has the particular advantage that the base hollow component is well fixable in position during the implementation of the method and protected from damage.

According to a preferred embodiment of the invention, a foam material is used which heats up to a temperature at least 20 ° C higher than the ambient temperature during the exothermic foaming. It is particularly preferred that the foam material at room temperature during the exothermic foaming warms to between about 100 ° C and 130 ° C. Such a foam material is particularly advantageous for hollow components made of a material which is particularly sensitive to temperature, in order to avoid excessive temperature loading.

Preferably, a foam material is used, which is designed for the independent formation of an adhesive bond with the component wall. Alternatively or additionally, prior to the introduction of the foam material, an adhesive can be applied to the side of the component wall that has been sent to the cavity, e.g. by spray application. An adhesive bond between the foam and the component wall has the advantage that with simple means relative movements between the foam and the component wall, in particular due to vibrations, are effectively prevented in this way. An erosive wear of the foam is thus avoided or at least reduced. A foam material, which is designed for the independent formation of an adhesive bond with the component wall has the advantage that an additional joining method, such. Gluing is no longer necessary. As a result, the manufacturing process can be simplified and thus manufacturing costs can be reduced.

It is preferred that the foam material has at least two components which are mixed together for foaming. Preferably, the foam material has two components. Such a foam material is also referred to as a two-component foam material. The two components can be stored separately from each other. By mixing the two components of the foaming process is initiated. It is preferred that the foaming process not take place directly during mixing of the components or immediately after mixing, but with a delay, so that a distribution of the foam material is ensured within the cavity. Too early solidification entails the risk that the foam material can not penetrate into some areas of the reinforcement area of the cavity, since a distribution of the foam material can be hindered by the already formed foam. With such a foam material of several components, the foaming process is easy to control.

More preferably, the foam material is injected during introduction by means of a nozzle in the cavity. For this example, a mixing nozzle can be used, in which the components are already mixed in the nozzle. Alternatively, an injection nozzle can be used, by means of which the components are injected into the cavity in such a way that the components are mixed with one another after leaving the nozzle. Injection by means of a nozzle has the advantage that a uniform distribution of the foam material within the cavity and a mixing of the components are improved.

It can be provided according to the invention that during the monitoring of the heating an actual heat distribution is determined via the component wall and compared with a desired heat distribution, wherein the generated fiber composite structure component is sorted out when exceeding a deviation threshold value. The target heat distribution describes the heat distribution over the component wall, if the foam in the reinforcement area is evenly distributed within the cavity and lies flat against the component wall. An actual heat distribution, which has colder areas than the target heat distribution, is an indication that in these areas the foam is not attached to the component wall or there is a significant mixing error. The greater the deviation, the more defective is the formation of the foam. By means of such monitoring, quality monitoring of the manufactured structural components is possible in a simple and cost-effective manner.

Preferably, a base hollow member is provided, which is formed as a fiber composite structural component, wherein the component wall having a matrix material impregnated fibers. Such basic hollow components have high strength and high load capacity with low weight.

According to a second aspect of the invention, the object is achieved by a structural component. The structural component has a component wall, a cavity surrounded by the component wall, and a reinforcement region. The cavity is filled in the gain region with a pressure-stable and / or energy-absorbing, solid foam, which contacts the component wall in the reinforcing region surface. The structural component according to the invention has the same advantages as already described above for the method according to the invention for producing a load-optimized structural component in a reinforcement region according to the first aspect of the invention. Accordingly, the structural component according to the invention is particularly pressure-stable and / or has a particularly high energy absorption capacity. Furthermore, the structural component has a low density and is inexpensive and can be produced by simple means.

Preferably, the structural component is produced by means of a method according to the invention. The process can be carried out with simple means and inexpensively. It is also possible to economically produce large-scale structural components in mass production by means of the method.

According to a third aspect of the invention, the object is achieved by a device for producing a load-optimized structural component in a reinforcement region. The device has a closable receiving mold with a receiving cavity for receiving at least one reinforcement region of a base hollow component, a delivery unit for introducing flowable foam material into at least one access opening of the base hollow component and a heat detection device for monitoring a heating of a component wall of the generated structural component. The device is designed for carrying out a method according to the invention. The device according to the invention has the same advantages as already described above for the method according to the invention for producing a load-optimized structural component in a gain region according to the first aspect of the invention.

A device according to the invention and a structural component according to the invention are explained in more detail below with reference to drawings. Each show schematically:

1 in a side view a basic hollow component,

2 in a sectional view of the base hollow component 1 .

3 in a side view from the Grundhohlbauteil 1 manufactured structural component,

4 in a sectional view of the structural component 3 , and

5 in a side view of an inventive device.

Elements with the same function and mode of action are in the 1 to 5 each provided with the same reference numerals.

In 1 and 2 is schematically a Grundhohlbauteil 2 shown in different views. The basic hollow component 2 is formed in this embodiment, a hollow cylinder and has a component wall 3 on that a cavity 4 surrounds. In the component wall 3 is an access opening 5 designed for filling liquid foam material. The basic hollow component 3 is designed as a fiber composite component. In the Grundhohlbauteil shown here 2 it is just an example for illustration. Basic hollow components 2 According to the invention, they can have virtually any shape, in particular with curvatures, edges, curves or the like.

In 3 and 4 is a structural component 1 shown in different views, wherein the structural component 1 from the basic hollow component 2 out 1 and 2 is made. The cavity 4 the basic hollow component 2 is with a foam 6 filled. In this example is the access opening 5 also with foam 6 filled. According to the invention can also be provided that the access opening 5 with another material, eg a material of the component wall 3 is closed. The foam 6 contacts the component wall 3 flat and consistent.

5 schematically shows a side view of an inventive device 10 for producing a load-optimized structural component in a reinforcement region 1 , The device 10 has a recording form 11 with a shell 11a and a lower part 11b on that over a hinge 17 connected to each other, so that the top 11a relative to the lower part 11b is pivotally held on this. In the recording form 11 is a recording cavity 12 formed, the shape and size of the Grundhohlbauteils 2 out 1 corresponds and thus for receiving the Grundhohlbauteils 2 is trained. The receiving cavity 12 is evenly on the upper part in this embodiment 11a and lower part 11b distributed. At the top 11a is a delivery unit 13 with a nozzle 16 for introducing the liquid foam material into the cavity 4 of the base hollow body 2 arranged. In the shell 11a and lower part 11b each are several coolant channels 15 for cooling the recording form 11 and thus the component wall 3 of the base hollow body 2 arranged. About the recording form 11 is a heat detection device 14 , For example, an infrared camera, to monitor the heating of the component wall 3 arranged.

LIST OF REFERENCE NUMBERS

1

structural component

2

Basic hollow component

3

component wall

4

cavity

5

access opening

6

foam

10

contraption

11

receiving mold

11a

top

11b

lower part

12

receiving cavity

13

inserting unit

14

Heat detection device

15

Coolant channel

16

jet

17

hinge

Claims (14)

Method for producing a load-optimized structural component in a predefined reinforcement region ( 1 ), comprising the steps: - providing a base hollow component ( 2 ) with a component wall ( 3 ), at least one of the component wall ( 3 ) surrounded inner cavity ( 4 ) as well as at least one the component wall ( 3 ) from the outside to the cavity ( 4 ) penetrating access opening ( 5 ), - introducing a flowable foam material into the cavity via the at least one access opening ( 5 ), wherein the foam material is formed, in an exothermic reaction to a pressure-stable and / or energy-absorbing, solid foam ( 6 ), - distributing the foam material at least within the reinforcement region of the cavity ( 4 ), - foaming the foam material into a solid foam ( 6 ) such that the foam ( 6 ) at least in the reinforcing region of the base hollow component ( 2 ) the cavity ( 4 ) and in the reinforcement area the component wall ( 3 ) contacted flat over the entire area, and - monitoring of heating of the component wall ( 3 ) over the reinforcement region by means of a heat detection device ( 14 ). Method according to claim 1, characterized in that the base hollow component ( 2 ) is provided such that at least the reinforcing region of the hollow component ( 2 ) in a receiving cavity ( 12 ) a closable recording form ( 11 ) and the recording form ( 11 ) is subsequently closed, wherein the receiving cavity ( 12 ) has a shape and size which corresponds to a shape and size of the reinforcing region of the base hollow component (FIG. 2 ) corresponds or at least substantially corresponds. Method according to claim 2, characterized in that the receiving form ( 11 ) is cooled to dissipate the heat generated during foaming. Method according to claim 2 or 3, characterized in that the receiving cavity ( 12 ) is formed in such a way, in the closed state of the receiving form ( 11 ) an expansion of the base hollow component ( 2 ) form-fitting limit. Method according to one of claims 2 to 4, characterized in that the entire basic hollow component ( 2 ) in the receiving cavity ( 12 ) is arranged. Method according to at least one of the preceding claims, characterized in that a foam material is used which heats up during the exothermic foaming to a temperature which is at least 20 ° C higher than the ambient temperature. Method according to at least one of the preceding claims, characterized in that a foam material is used, which is used for the independent formation of an adhesive bond with the component wall ( 3 ) is trained. Method according to at least one of the preceding claims, characterized in that the foam material has at least two components which are mixed together for foaming. Method according to at least one of the preceding claims, characterized in that the foam material when introduced by means of a nozzle ( 16 ) into the cavity ( 4 ) is injected. Method according to at least one of the preceding claims, characterized in that during the monitoring of the heating an actual heat distribution over the component wall ( 3 ) and compared with a desired heat distribution, wherein when a deviation threshold value is exceeded, the produced fiber composite structural component ( 1 ) is sorted out. Method according to at least one of the preceding claims, characterized in that a base hollow component ( 2 ) provided as a fiber composite structural member, wherein the component wall ( 3 ) having a matrix material impregnated fibers. Structural component ( 1 ), comprising a component wall ( 3 ), one of the component wall ( 3 ) surrounded cavity ( 4 ) and a reinforcement region, characterized in that the cavity ( 4 ) in the reinforcement region with a pressure-stable and / or energy-absorbing, solid foam ( 6 ), which covers the component wall ( 3 ) contacted flat in the gain area. Structural component ( 1 ) according to claim 12, characterized in that the structural component ( 1 ) is produced by a method according to any one of claims 1 to 11. Contraption ( 10 ) for producing a load-optimized structural component in a reinforcement region ( 1 ), comprising a closable recording form ( 11 ) with a receiving cavity ( 12 ) for the positive reception of at least one reinforcement region of a base hollow component ( 2 ), a feed unit ( 13 ) for introducing flowable foam material into at least one access opening ( 5 ) of the hollow component ( 2 ) and a heat detection device ( 14 ) for monitoring a heating of a component wall ( 3 ) of the generated structural component ( 1 ), characterized in that the device ( 10 ) is designed for carrying out a method according to one of claims 1 to 11.

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