EP2557389B1 - Structure component for an operational missile system - Google Patents

Description

FIELD OF THE INVENTION

The invention relates to a mechanical structural component for an operational missile system, to a method for producing the structural component in connection with the use of metal foam for the structural component.

BACKGROUND OF THE INVENTION

In the military field of missile systems, numerous types of missiles are used, such as rockets and cruise missiles, some of which are also made in large numbers and for single use. In contrast to strategic missiles such as ICBMs or space launch systems, operational missile systems always require immediate operational readiness without the need for any special upgrading measures prior to deployment.

The structural concepts and manufacturing methods used, which have proven successful in missiles with high accuracy requirements and in mostly smaller numbers, can lead to high costs for missiles with low or medium accuracy requirements, which are sometimes made in very large quantities.

In connection with the associated design and layout rules in development, these production methods increasingly come up against limits with regard to the achievable unit costs, since from certain batch sizes no significant cost reductions can be made possible any more. As examples here can be "Lost Cores "for producing ribbed inner contours of castings with undercuts and the wear of pusher tools are called.

On the other hand, the complexity of supporting structural components can not be reduced arbitrarily, since they must provide, for example, all mechanical interfaces, must meet thermal and EMC requirements and / or at the same time can influence the aerodynamics of the missile outer skin.

As a rule, structural components represent weight, stiffness and accuracy-relevant components for integrated drive kinematics, which can also decisively influence the integration effort during assembly of the missile.

In the US 3,674,585 A For example, a substantially hollow wing structure is described which includes an outer skin, a layer of foam material, and a reinforcing layer of fiberglass material.

The GB 2 402 196 A describes a balloon basket having an outer member with a porous region.

SUMMARY OF THE INVENTION

It is an object of the invention to produce missiles more cost-effectively.

This object is solved by the subject matter of the independent claims. Further embodiments of the invention will become apparent from the dependent claims and from the following description.

A first aspect of the invention relates to a structural component for a missile, in particular for an operational missile system.

The missile may be an unmanned missile. The missile may have a drive, but need not include a drive. Overall, it should be understood that the term "missile" in the following with the English term "missile" equates, which can describe a rocket, a cruise missile and a projectile.

A missile in this sense can be designed to detect a potential target, to head for this goal and / or to develop a desired effect there. The missile may include means and devices to perform at least one of these tasks independently. It is also possible that the missile is remotely controlled at least temporarily.

In particular, the missile may be a military missile, so may be used to combat a target. For example, the missile may comprise an explosive device and / or be designed for single use. However, it is also possible that the missile is used for reconnaissance purposes and / or returns to its launch site.

A structural component may be a component of the missile which serves for mechanical support, mechanical vibration damping, electrical ground connection, electromagnetic shielding, as heat sink and / or for thermal shielding of at least one further component of the missile. This further component may include, for example, the drive, the controller, and / or the payload of the missile. It is also possible that another component is another structural component.

A structural component may comprise at least one mechanical interface for a further component, via which the further component is mechanically supported by the structural component. In particular, a structural component can essentially form the complete support structure of the missile or at least one segment of the missile.

According to the invention, the structural component forms a segment of the operational missile system which provides a support structure of the operational missile system and an outer surface of an outer portion of the operational missile system, wherein the segment is formed of a metal foam body. The metal foam body can serve for mechanical stiffening and / or mechanical damping and / or electrical shielding or ground connection of the structural component or the missile.

A metal foam can be described as a solid metal body, which has randomly distributed cavities (or pores) in its interior, the volume of which accounts for most of the volume filled by the solid. As the metal, for example, aluminum or an aluminum alloy can be used.

The use of metal foam can provide numerous benefits in terms of both the manufacture of the missile and the missile itself.

Numerous networked cavities and, in particular, the use of a light metal such as aluminum result in lightweight and resilient structural components for the missile. The structural components can be compared with the construction of bone, which have high strength with low weight.

Metal foam is usually easy to process and to the desired shape. Even complicated shaped parts can be produced by foaming a corresponding shape and possibly by a subsequent mechanical finishing. In combination with the low material consumption thus the total piece costs of missiles, especially for large quantities, can be reduced.

By a relatively low-cost foaming process inner and outer contours of the missile structures without weight gain can be made simpler, resulting in a manufacturability with reduced tooling costs. For example, the molds can be made simpler.

The mechanical and electrical strongly attenuating properties of metallic pore structures can be made directly usable in terms of EMC.

The mechanical interfaces to other components can be redesigned due to the use of metal foam, which can also lead to further cost reduction. For example, connections to other components or components of the missile can be created with foamed inlays and large-area adhesive surfaces.

Another non-inventive aspect relates to a use of metal foam for a structural component of a missile or the use of metal foam in a structural component of a missile.

According to one embodiment of the invention, the metal foam body comprises closed-cell metal foam. With closed-cell metal foam, a denser (ie impermeable to liquids and gases) metal foam body with smooth surfaces can be created. For a closed-cell metal foam For the most part, the pores do not communicate with each other. The metal foam body can be constructed like a bone in this case.

However, it is also possible for the metal foam body to comprise open-pored metal foam. In an open-pored metal foam, the pores can be largely crosslinked with each other. The metal foam body can thus be constructed like a sponge.

According to the invention, the structural component with an outer surface forms an outer portion of the missile. For example, a surface of the structural component may form an outer surface of the missile. Such outer or inner boundary surfaces of the foam body may additionally be provided by a (non-bearing) coating or thin-walled parts adhering thereto (such as sheet metal parts, pipes, etc.) and stiffen. In this way, the missile may for example be at least partially constructed of segments of metal foam that provide the inner support structure and the outer shell of the missile.

The outer surface may form part of the shell or the outer skin of the missile. On the other hand, the structural component can provide struts inside the missile. A part or the entire integral structure of the missile may be formed with the metal foam.

According to the invention, the missile may comprise a plurality of segments. The support structure of the missile or at least the segment may consist essentially entirely of metal foam. In this way, it is possible to dispense almost completely with further supporting structures in addition to the metal foam.

According to one embodiment of the invention, the metal foam body is formed by machining a metal foam blank. By way of example, the metal foam body can be produced within a (reusable mold) and can be partially post-machined after solidification. Especially with closed-pore metal foam, a subsequent processing by changing the surface or by the visibility of the pores can be seen.

According to one embodiment of the invention, the metal foam body is formed within a foaming mold or by foaming a mold. Possibilities for forming metal foam are described below. For example, a metal powder can be mixed with a blowing agent and then compacted into semi-finished products, which are poured into a mold and liquefied by heating. The propellant gasses in the liquid phase and creates the voids that remain after solidification of the metal.

According to one embodiment of the invention, the metal foam body has a first density at at least one first location and a second density that differs from the first density at at least one second location. For example, the bulk density of the semifinished products from this starting material and / or the structure of the casting mold can be achieved via the composition of the starting material, so that the foaming density in places via the metering of the blowing agent or via the locally introduced mass of compacted semi-finished products (according to bulk density) at the first Produces more gas than at a second location, which in the first place larger pores and the density of the metal foam at this point decreases.

In this way, a density gradient can also be generated in a targeted manner. This can be realized with a locally controlled density distribution of the metal foam targeted metering of the material used. This possibility can be achieved a minimum weight for topologically optimal lightweight structures can be used. For example, the metal foam body may have a closed shell with a porous core, which has a density distribution corresponding to the mechanical load, as it is known from the bone structure.

According to one embodiment of the invention, the structural component comprises at least one component of the missile which is completely or partially foamed or enclosed in the metal foam body. Several components at the same time can be foamed into the metal foam. In this way, complicated support structures for the component can be completely eliminated. The mechanical connection of several components can be realized in a simple manner.

According to one embodiment of the invention, the structural component comprises at least one insert (also called inlay), which is connected to the metal foam body and which serves for fastening a further component of the missile. The insert can be foamed during the production of the metal foam body or can be glued into a corresponding recess of the metal foam body. Such inserts can form reference and contact surfaces and at the same time form elements such as threads, adhesive surfaces, etc. record.

Another aspect of the invention relates to a method for producing a structural component of a missile with metal foam.

On the one hand, a metal foam body of the structural component can be formed by machining a metal foam blank. However, the metal foam body can also be produced in the desired shape (for example by forming the metal foam body contour corresponding to the mold to be foamed out) and subsequently optionally be reworked. Also, a plurality of metal foam bodies can be connected or foamed together by means of other methods within a common mold. In particular mechanically processed foam surfaces can form ideal conditions for solid potting to be integrated components by their open porosity. Subsequently, a segment of the operational missile system is formed from the metal foam body, wherein the segment provides a support structure of the operational missile system and an outer side of an outer portion of the operational missile system.

According to one embodiment of the invention, the method comprises the steps of providing a hollow body blank and reshaping the hollow body blank by means of a hydroforming process to form a hollow body with a desired contour, which can represent an outer skin and / or inner skin of the missile. This is also a bulkhead, z. B. as thermal protection against an engine duct, feasible. In this step, a deliberately introduced, thermal bias for selectively influencing the thermal expansion and deformation properties of the later structural component can be generated.

According to one embodiment of the invention, the method comprises the steps of coating at least one inner surface of a hollow body or bodies with an adhesive layer, for example nickel, and forming the metal foam body by foaming the hollow body. In other words, the casting mold can be a later component of the missile. It is also possible that a hollow body is foamed, which then forms an inner contour of the metal foam body.

Thus, the structural component can be formed as a hybrid structure of a metal foam body and an example thin-walled hollow body.

Due to the adhesion of the metal foam on nickel-plated surfaces, there is an almost unlimited possibility of expansion to hybrid structures in connection with thin-walled profiles, which can be attached and integrated in a kink-resistant and buckling-free manner. For this purpose, both outer and inner contours come into question, which can be produced by hydroforming process.

According to one embodiment of the invention, the method comprises the step of: lathering and / or foaming a component of the missile into the metal foam body. For example, components of drive, control and / or payload can be firmly connected to the support structure in this way.

According to one embodiment of the invention, the method comprises the steps of coating the metal foam body with a coating for protecting outer surfaces, inner surfaces and / or interface surfaces of the missile.

Embodiments of the invention will now be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

• Fig. 1 shows a schematic external view of a missile according to a first embodiment of the invention.
• Fig. 2 shows a schematic view of the missile Fig. 1 in cross section.
• Fig. 3 shows a flowchart for a method for producing a structural component according to an embodiment of the invention.
• Fig. 4 shows a flowchart for a method for producing a structural component according to another embodiment of the invention.
• Fig. 5 shows a flowchart for a method for producing a structural component according to another embodiment of the invention.

The reference numerals used in the figures and their meaning are listed in summary form in the list of reference numerals. Basically, identical or similar parts are provided with the same reference numerals.

DETAILED DESCRIPTION OF EMBODIMENTS

The Fig. 1 shows an operational missile system 10 in the form of a cruise missile 10 with elevation and Leitruder 12, which has a substantially torpedo-shaped outer contour. The cruise missile 10 is divided into a plurality of sections or segments 14a, 14b, 14c, 14d in the longitudinal direction, which can be manufactured separately from each other and finally connected to each other.

Like in the Fig. 2 is indicated, each of the segments 14a, 14b, 14c, 14 comprises a structural component 18a, 18b, 18c, 18d.

The structural component 18a comprises a metal foam body 20a, 20a ', in which a plurality of inserts 24 are incorporated, which have connecting elements such as a thread, an adhesive surface or a spring tongue. A component 22a, for example a camera system, is partially surrounded by the metal foam body 20a, 20a 'and connected via the inserts 24 to the metal foam body 20a, 20a'. The part of the metal foam body 20a has a higher density than the part of the metal foam body 20a '. Instead of the component 22a, a payload 22a, such as an explosive device, may also be fastened in the metal foam body 20a, 20a '.

The structural component 18b comprises two metal foam bodies 20b, 20b '. The tubular metal foam body 20b has been foamed, for example, in a recyclable form, the metal foam body 20b ', for example, cut out of a blank. The metal foam body 20b, 20b 'have been connected to one another and to a component 22b, for example a control computer, and the resulting structural component 18b has been coated with a coating 28 intended to protect the missile 10 from the effects of the weather.

In general, the individual metal foam bodies 20b, 20b 'may either be milled out of a metal foam blank or foamed in a reusable form. Thereafter, the two bodies 20b, 20b 'may be joined together (e.g. by gluing, soldering or welding) and coated with a coating 28.

The structural component 18c comprises a thin-walled tubular hollow body 26 in the interior of which a component 18c, for example a tank, is arranged. The component 18 c is foamed into a metal foam body 20 c, which in turn was produced by foaming the hollow body 26.

The structural component 18d comprises a metal foam body 20d, which has been produced from a metal foam blank by reworking. Into the cylindrical opening in the metal foam body 20d, a member 22d such as an electromechanical adjusting system was inserted and bonded to the metal foam body 20d.

The electromechanical actuating system 22d can be foamed in metal foam analogously to 18c.

Regarding the Fig. 3 to 5 Production methods for the structural components 18a to 18d are given. It should be understood that an entire missile 10, and not just the sections or segments, may be manufactured by the described methods. The methods can be combined. Steps of the methods may be omitted.

Metal foam can generally be made in the following manner: First, a starting material comprising a metal and a blowing agent is provided. Subsequently, the starting material is heated, wherein the metal is liquefied and the propellant releases a gas, so that pores are formed in the metal and the metal foam is formed. The starting material can be placed in a mold and then heated. Also, the starting material may be first heated and then filled in liquid form into the mold. After solidification of the liquid metal, the pores remain in the metal.

However, there are known other methods in which, for example, a matrix of small bodies with liquid metal is poured over, which are dissolved out of the resulting body after the solidification of the metal. The remaining metal material can also be considered as a metal foam.

The Fig. 3 shows a flowchart for a method for producing the structural component 18d from a blank, which is reworked.

In a step S10, a metal foam blank is provided, which in the present case may have substantially the shape of a cylinder.

In a step S12, the blank is machined, for example, by milling a cylinder opening and / or by removing material on the outside) to form the metal foam body 20d.

In a step S14, the component 22d is inserted into the metal foam body 20d and glued.

In a step S16, the outer surface of the metal foam body 20d is coated with a coating, for example to form a circumferentially resistant outer surface.

The Fig. 3 shows a flowchart for a method for producing the structural component 18c by foaming.

In a step S30, a metal blank, for example a pipe, is provided.

In a step S32, a base component 26 is formed by hydroforming the metal blank. In hydroforming, a blank is placed in a reusable form which, for example, in a tube, can form an internal cavity mold with two punches at the end. Thereafter, a pressure is built up on the (or in) the blank, so that the blank is applied to a surface of the mold. In the present case, the metal blank is subjected to high pressure in the interior, which presses it against the inside of the mold.

In a step S34, the base component 26 is coated on the inside with nickel.

In a step S36, the component 22c is inserted into the base component 26.

In a step S38, the component 22c is foamed in the base component 26, so that the metal foam body 20c is formed. Due to the nickel coating, the metal foam body connects to the base component 26.

The Fig. 3 shows a flowchart for a method for producing the structural component 18a by foaming or foaming.

In a step S50, a reusable form is provided. The mold can be provided on its inner surfaces with a release agent.

In a step S52, a first quantity of primary material is arranged at a first position of the mold and a second quantity of primary material is arranged at a second position of the mold.

In a step S54, the inserts 24 are arranged in the mold.

In a step S56, the starting material is heated in the mold so that a metal foam 20a having a first pore size is formed at the first location and a metal foam 20a 'having a second pore size is formed at the second location.

In a step S58, the reusable mold is removed after cooling the metal foam.

In a step S60, the component 22a is inserted into the metal foam body 20a, 20a 'and the component 22a is connected to the metal foam body 20a, 20a' via the inserts 24.

In a step S62, the structural component 18a is coated with a coating 28.

The openings in the metal foam body 20a, 20a 'for the inserts 24 can also be milled in the metal foam body 20a, 20a' or provided during casting. The inserts 24 can then be glued into these openings in this case.

In addition, it should be noted that "encompassing" does not exclude other elements or steps, and "a" or "an" does not exclude a multitude. It should also be appreciated that features or steps described with reference to any of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be considered as limiting.

LIST OF REFERENCE SIGNS

10

Cruise missiles

12

Height / Leitruder

14a, 14b, 14c, 14d

Section of the missile

18a, 18b, 18c, 18d

structural component

20a, 20a ', 20b, 20b'

Metal foam / metal foam body

20c, 20d

Metal foam / metal foam body

22a, 22b, 22c, 22d

component

24

Insert (inlay)

26

hollow body

28

coating

Claims (11)

1. Structural component (18a, 18b, 18c, 18d) of an operational missile system (10),
   wherein the structural component (18a, 18b, 18c, 18d) forms one segment (14a, 14b, 14c, 14d) of the operational missile system (10) which provides a supporting structure of the operational missile system (10) and an external surface of an external portion of the operational missile system (10),
   wherein the segment (14a, 14b, 14c, 14d) is provided from a metallic foam body (20a, 20a', 20b, 20c, 24d),
2. Structural component (18a, 18b, 18c, 18d) according to claim 1,
   wherein the metallic foam body comprises closed-cell metallic foam, and/or
   wherein the metallic foam body comprises aluminium or an aluminium alloy.
3. Structural component (18d) according to any one of the preceding claims,
   wherein the metallic foam body (20d) is provided by means of machining a metallic foam blank.
4. Structural component (18c) according to any one of the preceding claims,
   wherein the metallic foam body (20c) is provided by means of packing a mould with foam.
5. Structural component (18a) according to any one of the preceding claims,
   wherein the metallic foam body (20a, 20a') has at least at a first location a first density and at a second location a second density which differs from the first density.
6. Structural component (18c) according to any one of the preceding claims, wherein the structural component comprises at least a component (22c) of the missile which is enclosed in the metallic foam body (20c).
7. Structural component (18a) according to any one of the preceding claims, wherein the structural component comprises at least an inlay (24) which is connected to the metallic foam body (20a, 20a') and serves to affix an additional component (22a) of the missile.
8. Method for manufacturing a structural component of an operational missile system, comprising the steps:

   production of a metallic foam body by means of machining a metallic foam blank or by means of forming the metallic foam body contour corresponding to a mould which is to be packed with foam;

   formation of a segment (14a, 14b, 14c, 14d) of the operational missile system (10) from the metallic foam body, wherein the segment provides a supporting structure of the operational missile system (10) and an external surface of an external portion of the operational missile system (10).
9. Method according to claim 8, additionally comprising the steps:

   provision of a hollow body blank;

   reforming a hollow body blank by means of an internal high-pressure forming process to make a hollow body;

   coating at least one surface of the hollow body with an adhesive coating;

   forming the metallic foam body by means of packing the hollow body with foam and/or enveloping a hollow body in foam which forms an internal contour of the metallic foam body.
10. Method according to any one of claims 8 to 9, additionally comprising the steps:

    filling and/or packing with foam a component of the missile into the metallic foam body.
11. Method according to any one of claims 8 to 10, additionally comprising the step:

    applying a coating to a metallic foam body for the protection at least of an external surface, internal surface or sectional surface of the missile.

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